Forecast track record

How the forecasts have done, GSA by GSA. Readings through Sep 2026. Two records, kept apart: the backtest (the model given the real precipitation and water supply) and the live record (what this site published under NOAA's outlook).

Backtest: of the forecasts made 12 months ago (Sep 2025), 164 of 192 GSAs landed inside their 80 % range in Sep 2026; typical miss 3.0 ft, about as often too deep as too shallow.

57 of the 192 had wells read in Sep 2026; for the others, the average holds their latest readings.

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How this is scored

Actual is the kriged average of the GSA or subbasin for that month, the line the map's charts draw, as of the latest refresh. Late readings can still move recent months a little.
Miss = forecast minus actual. Plus means the forecast was too deep, minus too shallow.
80 % range is the band the map draws: sized from backtest errors per area and month ahead, so about 8 in 10 months fall inside (cross-validated). In the backtest the ranges are partly in-sample; the live record is the real test. Live editions saved before the range was stored with them use today's range.
Typical miss in the table: the mean absolute miss over every scored month at 1, 6 or 12 months ahead. In the headline: the median miss across GSAs. Bias: the mean miss at 12 months.
Wells read: monitoring wells in the area with a reading that month. With none, the average is held from recent readings; months with no average are not scored.
Backtest: rolled forward from each month after the training cut-off; three seeds averaged. Live: the forecast published under NOAA's outlook each month, so its misses include the outlook's own misses. A retrain mark shows where the model changed between editions.
Grayed subbasins (too few wells to forecast) are left out.

Backtest

The model trained only on readings through Sep 2024, then given the precipitation and water supply that actually came. It tests the model, not the outlook. The GSA panel's "A year ago" chart shows the same numbers.

By month the forecast was made, 12 months ahead

Bar: share of GSAs inside their 80 % range.

Oct 24163/192

Nov 24171/192

Dec 24170/192

Jan 25172/192

Feb 25168/192

Mar 25175/193

Apr 25171/192

May 25171/192

Jun 25164/192

Jul 25161/192

Aug 25165/192

Sep 25164/192

By GSA

GSA	Subbasin	Made	For	Forecast	80 % range	Actual	Miss	Inside	Wells read	Typical miss 1 mo	6 mo	12 mo	Bias 12 mo
Tehama County Flood Control and Water Conservation District GSA	Antelope	Sep 25	Sep 26	39.2	36.6–41.6	41.0	−1.8	yes	5	0.9	1.4	1.5	−0.4
Tehama County Flood Control and Water Conservation District GSA	Bend	Sep 25	Sep 26	43.4	36.7–49.4	46.0	−2.6	yes	0	2.8	3.5	4.1	−4.1
Biggs-West Gridley Water District GSA	Butte	Sep 25	Sep 26	8.4	6.3–10.3	9.4	−1.0	yes	1	0.7	1.0	0.9	−0.5
Butte Water District GSA - Butte	Butte	Sep 25	Sep 26	17.3	14.9–19.5	18.8	−1.5	yes	0	1.0	1.1	1.0	−0.9
City of Biggs GSA	Butte	Sep 25	Sep 26	9.4	7.3–11.3	11.5	−2.1	no	0	0.7	0.7	0.9	−0.4
City of Gridley GSA	Butte	Sep 25	Sep 26	10.0	7.9–11.9	10.3	−0.3	yes	0	0.8	0.9	0.8	+0.2
Colusa Groundwater Authority GSA - Butte	Butte	Sep 25	Sep 26	6.2	4.1–8.1	7.4	−1.2	yes	1	0.6	0.8	0.7	−0.0
County of Butte GSA - Butte 1	Butte	Sep 25	Sep 26	20.9	18.8–22.8	22.2	−1.3	yes	0	0.8	0.8	0.7	−0.2
County of Butte GSA - Butte 2	Butte	Sep 25	Sep 26	20.9	18.8–22.8	22.2	−1.3	yes	0	0.8	0.8	0.7	−0.2
County of Glenn GSA - Butte	Butte	Sep 25	Sep 26	13.9	11.7–15.9	14.6	−0.7	yes	0	0.9	1.4	0.7	−0.4
Reclamation District No. 1004 GSA - Butte 1	Butte	Sep 25	Sep 26	11.3	9.2–13.2	12.3	−1.0	yes	7	0.9	1.0	0.6	−0.1
Reclamation District No. 1004 GSA - Butte 2	Butte	Sep 25	Sep 26	15.2	11.5–18.6	14.9	+0.3	yes	0	2.1	2.8	1.6	+1.5
Reclamation District No. 2106 GSA	Butte	Sep 25	Sep 26	14.7	12.6–16.6	16.8	−2.1	no	0	0.7	0.8	0.9	−0.2
Richvale Irrigation District GSA	Butte	Sep 25	Sep 26	6.3	4.2–8.2	7.4	−1.1	yes	2	0.7	0.8	0.9	−0.6
Western Canal Water District GSA	Butte	Sep 25	Sep 26	13.1	11.0–15.0	14.1	−1.0	yes	6	0.5	0.5	0.6	−0.2
Chowchilla Water District GSA	Chowchilla	Sep 25	Sep 26	234.7	228.8–240.0	238.7	−4.0	yes	0	2.8	2.2	3.8	−3.8
County of Madera GSA - Chowchilla	Chowchilla	Sep 25	Sep 26	191.5	179.1–202.7	178.5	+13.0	no	0	5.1	7.3	8.0	+4.0
County of Merced GSA - Chowchilla	Chowchilla	Sep 25	Sep 26	300.8	294.3–306.7	298.6	+2.2	yes	0	3.8	3.9	2.9	+2.9
Triangle T Water District GSA	Chowchilla	Sep 25	Sep 26	116.2	105.5–125.8	121.2	−5.0	yes	0	3.6	5.1	6.4	−6.4
Colusa Groundwater Authority GSA - Colusa	Colusa	Sep 25	Sep 26	56.6	46.5–65.7	65.6	−9.0	yes	51	3.6	5.5	6.7	−6.7
County of Glenn GSA - Colusa	Colusa	Sep 25	Sep 26	17.7	14.9–20.2	19.2	−1.5	yes	0	1.2	1.5	1.6	−0.1
Glenn Groundwater Authority GSA	Colusa	Sep 25	Sep 26	88.2	85.8–90.4	89.8	−1.6	yes	40	1.2	1.3	1.0	+0.0
Reclamation District No. 1004 GSA - Colusa	Colusa	Sep 25	Sep 26	12.1	9.7–14.3	13.4	−1.3	yes	0	1.3	1.4	0.9	−0.5
Corning Subbasin GSA	Corning	Sep 25	Sep 26	75.3	70.6–79.5	76.4	−1.1	yes	16	1.6	2.3	3.4	+3.2
County of Glenn GSA - Corning	Corning	Sep 25	Sep 26	19.3	17.2–21.2	19.6	−0.3	yes	0	0.8	0.7	0.6	+0.2
Tehama County Flood Control and Water Conservation District GSA	Corning	Sep 25	Sep 26	120.1	116.3–123.6	116.1	+4.0	no	32	2.0	2.2	1.8	+1.4
Amador County Groundwater Management Authority GSA	Cosumnes	Sep 25	Sep 26	54.9	42.3–66.3	36.4	+18.5	no	0	4.3	9.9	11.9	+11.9
City of Galt GSA	Cosumnes	Sep 25	Sep 26	100.3	97.7–102.7	101.8	−1.5	yes	0	0.7	1.3	1.5	+0.5
Clay Water District GSA	Cosumnes	Sep 25	Sep 26	182.2	179.2–184.9	183.6	−1.4	yes	0	1.2	2.1	0.9	−0.5
Galt Irrigation District GSA	Cosumnes	Sep 25	Sep 26	137.0	134.9–138.9	136.8	+0.2	yes	2	0.5	0.7	0.7	+0.7
Omochumne-Hartnell Water District GSA - Cosumnes	Cosumnes	Sep 25	Sep 26	91.8	86.1–96.9	88.9	+2.9	yes	0	2.5	2.8	3.0	+3.0
Sacramento County GSA - Cosumnes	Cosumnes	Sep 25	Sep 26	45.1	41.1–48.7	42.2	+2.9	yes	1	1.7	1.9	3.0	+3.0
Sloughhouse Resource Conservation District GSA - Cosumnes	Cosumnes	Sep 25	Sep 26	131.6	125.1–137.5	125.4	+6.2	yes	4	1.8	4.3	4.4	+4.4
Aliso Water District GSA	Delta-Mendota	Sep 25	Sep 26	115.3	107.1–122.7	121.4	−6.1	yes	0	6.3	7.5	4.0	+1.4
Central Delta-Mendota GSA	Delta-Mendota	Sep 25	Sep 26	201.0	187.9–212.8	191.7	+9.3	yes	2	3.7	7.5	7.9	+7.9
City of Dos Palos GSA	Delta-Mendota	Sep 25	Sep 26	18.6	15.2–21.7	17.9	+0.7	yes	0	1.5	1.7	2.4	+2.4
City of Firebaugh GSA	Delta-Mendota	Sep 25	Sep 26	42.4	27.1–56.2	54.9	−12.5	yes	0	7.6	7.9	10.3	−5.5
City of Gustine GSA	Delta-Mendota	Sep 25	Sep 26	29.8	20.6–38.0	32.6	−2.8	yes	0	2.8	5.4	6.7	−1.9
City of Los Banos GSA	Delta-Mendota	Sep 25	Sep 26	39.6	36.4–42.5	41.6	−2.0	yes	0	1.8	1.7	1.4	−1.2
City of Mendota GSA	Delta-Mendota	Sep 25	Sep 26	104.8	92.0–116.4	118.0	−13.2	no	0	5.8	9.6	6.0	−1.7
City of Newman GSA	Delta-Mendota	Sep 25	Sep 26	47.6	36.4–57.7	53.3	−5.7	yes	0	5.0	9.8	7.9	−7.6
City of Patterson GSA	Delta-Mendota	Sep 25	Sep 26	97.9	84.7–109.8	90.3	+7.6	yes	0	5.6	6.5	6.6	+6.6
County of Fresno GSA - Delta-Mendota Management Area A	Delta-Mendota	Sep 25	Sep 26	94.7	84.5–103.9	99.3	−4.6	yes	0	4.6	6.5	4.1	−0.6
County of Fresno GSA - Delta-Mendota Management Area B	Delta-Mendota	Sep 25	Sep 26	111.0	100.8–120.2	113.8	−2.8	yes	0	8.1	8.7	3.8	+1.5
County of Madera GSA - Delta-Mendota	Delta-Mendota	Sep 25	Sep 26	92.2	88.8–95.3	94.9	−2.7	yes	0	2.8	2.5	1.5	−0.2
County of Merced GSA - Delta-Mendota	Delta-Mendota	Sep 25	Sep 26	40.2	37.8–42.4	40.2	+0.0	yes	0	1.0	1.1	0.8	+0.7
DM-II GSA	Delta-Mendota	Sep 25	Sep 26	114.7	97.6–130.1	104.6	+10.1	yes	0	6.4	8.8	9.0	+9.0
Farmers Water District GSA	Delta-Mendota	Sep 25	Sep 26	83.7	63.4–102.0	100.8	−17.1	yes	1	6.6	9.7	9.0	+3.4
Grasslands GSA	Delta-Mendota	Sep 25	Sep 26	42.4	39.6–44.9	42.1	+0.3	yes	0	1.6	1.5	1.1	+0.8
Northwestern Delta-Mendota GSA	Delta-Mendota	Sep 25	Sep 26	92.6	77.9–105.8	82.4	+10.2	yes	0	6.3	7.2	6.7	+6.7
Oro Loma Water District GSA	Delta-Mendota	Sep 25	Sep 26	120.1	99.1–139.0	102.0	+18.1	yes	0	8.7	11.5	11.0	+11.0
Patterson Irrigation District GSA	Delta-Mendota	Sep 25	Sep 26	48.3	41.8–54.2	43.5	+4.8	yes	0	2.9	2.7	3.5	+3.5
San Joaquin River Exchange Contractors GSA	Delta-Mendota	Sep 25	Sep 26	45.3	42.7–47.7	48.6	−3.3	no	0	2.0	1.3	1.3	−1.1
Turner Island Water District GSA - Delta-Mendota	Delta-Mendota	Sep 25	Sep 26	44.3	28.1–58.9	69.9	−25.6	no	0	6.4	10.3	11.1	−10.3
West Stanislaus Irrigation District GSA	Delta-Mendota	Sep 25	Sep 26	110.7	93.6–126.1	99.3	+11.4	yes	2	8.8	9.0	7.1	+7.1
Widren Water District GSA	Delta-Mendota	Sep 25	Sep 26	129.8	113.9–144.1	117.9	+11.9	yes	0	13.7	8.6	7.7	+3.2
Byron-Bethany Irrigation District GSA - East Contra Costa	East Contra Costa	Sep 25	Sep 26	15.9	5.0–25.7	23.4	−7.5	yes	0	3.0	4.9	6.5	−6.5
City of Antioch GSA	East Contra Costa	Sep 25	Sep 26	24.0	20.2–27.5	26.9	−2.9	yes	0	1.6	2.1	2.0	−0.9
City of Brentwood GSA	East Contra Costa	Sep 25	Sep 26	48.0	44.2–51.5	48.7	−0.7	yes	0	1.9	2.2	1.8	−0.1
County of Contra Costa GSA	East Contra Costa	Sep 25	Sep 26	9.6	7.4–11.6	12.4	−2.8	no	0	0.6	1.0	1.4	−1.4
Diablo Water District GSA	East Contra Costa	Sep 25	Sep 26	29.7	27.1–32.1	29.0	+0.7	yes	0	1.3	1.4	1.5	+0.6
Discovery Bay Community Services District GSA	East Contra Costa	Sep 25	Sep 26	14.8	12.0–17.3	19.1	−4.3	no	0	0.7	1.9	2.4	−2.1
East Contra Costa Irrigation District GSA	East Contra Costa	Sep 25	Sep 26	25.5	23.4–27.4	25.1	+0.4	yes	0	1.0	0.8	0.9	+0.1
Central Delta Water Agency GSA	Eastern San Joaquin	Sep 25	Sep 26	12.0	9.6–14.2	14.2	−2.2	yes	0	1.0	1.0	1.3	+0.9
Central San Joaquin Water Conservation District GSA	Eastern San Joaquin	Sep 25	Sep 26	127.6	124.2–130.7	127.4	+0.2	yes	1	2.2	1.9	1.3	+1.3
City of Lodi GSA	Eastern San Joaquin	Sep 25	Sep 26	51.6	48.4–54.5	51.6	+0.0	yes	0	1.8	1.5	1.5	+1.5
City of Manteca GSA	Eastern San Joaquin	Sep 25	Sep 26	25.6	23.4–27.6	28.3	−2.7	no	1	0.7	0.9	1.7	−1.5
City of Stockton GSA	Eastern San Joaquin	Sep 25	Sep 26	34.2	30.8–37.3	31.2	+3.0	yes	1	1.8	1.6	2.0	+2.0
County of San Joaquin GSA - Eastern San Joaquin 1	Eastern San Joaquin	Sep 25	Sep 26	43.2	41.1–45.1	43.4	−0.2	yes	4	0.7	0.9	1.4	+1.4
County of San Joaquin GSA - Eastern San Joaquin 2	Eastern San Joaquin	Sep 25	Sep 26	39.6	37.2–41.8	38.6	+1.0	yes	0	1.8	0.8	1.1	+0.3
Eastside San Joaquin GSA	Eastern San Joaquin	Sep 25	Sep 26	150.7	142.0–158.6	155.0	−4.3	yes	0	3.7	5.3	4.6	−2.6
Linden County Water District GSA	Eastern San Joaquin	Sep 25	Sep 26	162.8	154.9–169.9	156.3	+6.5	yes	0	2.6	4.0	5.1	+5.1
Lockeford Community Service District GSA	Eastern San Joaquin	Sep 25	Sep 26	138.0	125.9–148.9	148.2	−10.2	yes	0	2.3	6.2	7.4	−0.4
North San Joaquin Water Conservation District GSA	Eastern San Joaquin	Sep 25	Sep 26	141.3	129.9–151.6	129.3	+12.0	no	1	2.8	8.4	16.4	+16.4
Oakdale Irrigation District GSA	Eastern San Joaquin	Sep 25	Sep 26	110.8	99.2–121.3	117.3	−6.5	yes	0	1.4	5.7	7.2	+0.5
South Delta Water Agency GSA	Eastern San Joaquin	Sep 25	Sep 26	25.0	22.2–27.5	24.4	+0.6	yes	0	1.9	1.1	0.8	+0.1
South San Joaquin GSA	Eastern San Joaquin	Sep 25	Sep 26	58.3	56.2–60.2	59.7	−1.4	yes	8	0.8	0.5	0.9	−0.5
Stockton East Water District GSA	Eastern San Joaquin	Sep 25	Sep 26	149.3	143.8–154.2	145.8	+3.5	yes	4	2.3	2.8	2.9	+2.2
Woodbridge Irrigation District GSA	Eastern San Joaquin	Sep 25	Sep 26	30.7	27.7–33.4	33.5	−2.8	no	0	1.6	1.9	1.2	+0.4
East Kaweah GSA	Kaweah	Sep 25	Sep 26	90.1	78.9–100.2	84.7	+5.4	yes	0	5.8	6.6	5.9	+5.9
Greater Kaweah GSA	Kaweah	Sep 25	Sep 26	126.8	118.1–134.7	123.1	+3.7	yes	7	5.0	4.8	3.9	+3.8
Mid-Kaweah GSA	Kaweah	Sep 25	Sep 26	168.9	163.2–174.0	170.0	−1.1	yes	8	3.1	3.0	2.9	−1.3
Arvin GSA	Kern County	Sep 25	Sep 26	338.7	332.8–344.0	343.1	−4.4	yes	0	2.5	2.6	3.4	−3.4
Buena Vista Water Storage District GSA	Kern County	Sep 25	Sep 26	152.3	139.9–163.5	144.2	+8.1	yes	0	4.1	7.6	7.0	+7.0
Cawelo Water District GSA	Kern County	Sep 25	Sep 26	518.8	506.8–529.6	520.0	−1.2	yes	0	7.9	7.1	2.0	−1.3
Greenfield County Water District GSA	Kern County	Sep 25	Sep 26	229.2	221.7–236.0	226.9	+2.3	yes	0	4.8	4.6	4.1	+1.0
Henry Miller Water District GSA	Kern County	Sep 25	Sep 26	134.5	79.4–184.2	101.4	+33.1	yes	0	20.9	32.2	37.8	+37.8
Kern Non-Districted Land Authority GSA	Kern County	Sep 25	Sep 26	433.7	419.2–446.7	434.5	−0.8	yes	0	6.0	7.3	2.5	−1.9
Kern River GSA	Kern County	Sep 25	Sep 26	206.6	200.1–212.5	210.0	−3.4	yes	0	3.4	5.0	4.6	+2.0
Kern Water Bank GSA	Kern County	Sep 25	Sep 26	154.6	126.6–179.8	137.6	+17.0	yes	0	12.7	16.5	19.9	+19.9
Kern-Tulare Water District GSA - Kern County	Kern County	Sep 25	Sep 26	559.1	515.4–598.5	532.7	+26.4	yes	0	18.7	20.9	25.1	−7.9
North Kern Water Storage District GSA	Kern County	Sep 25	Sep 26	337.2	328.9–344.7	334.5	+2.7	yes	0	4.4	6.1	1.7	+0.5
Olcese Water District GSA	Kern County	Sep 25	Sep 26	114.1	106.2–121.2	119.7	−5.6	yes	0	4.1	4.4	2.7	−1.5
Pioneer GSA	Kern County	Sep 25	Sep 26	147.8	133.3–160.8	137.8	+10.0	yes	0	6.7	10.0	12.7	+12.7
Rosedale-Rio Bravo Water Storage District GSA	Kern County	Sep 25	Sep 26	238.1	221.7–252.9	232.4	+5.7	yes	0	5.8	9.3	10.3	+10.3
Semitropic Water Storage District GSA	Kern County	Sep 25	Sep 26	272.5	252.7–290.3	260.5	+12.0	yes	0	11.1	12.4	11.5	+11.5
Shafter-Wasco Irrigation District GSA	Kern County	Sep 25	Sep 26	353.5	347.6–358.8	350.9	+2.6	yes	0	2.8	3.9	2.2	+1.7
Southern San Joaquin Municipal Utility District - GSA	Kern County	Sep 25	Sep 26	335.8	309.7–359.3	322.5	+13.3	yes	0	12.4	12.6	11.2	+11.2
Tejon-Castac Water District GSA	Kern County	Sep 25	Sep 26	357.5	345.3–368.5	351.5	+6.0	yes	0	4.7	6.5	5.9	+5.9
West Kern Water District GSA	Kern County	Sep 25	Sep 26	128.0	82.7–168.8	113.6	+14.4	yes	0	12.1	29.2	37.3	+37.3
Westside District Water Authority GSA	Kern County	Sep 25	Sep 26	205.5	192.5–217.2	211.3	−5.8	yes	0	7.4	5.8	6.9	−6.9
Wheeler Ridge-Maricopa GSA	Kern County	Sep 25	Sep 26	279.8	242.7–313.3	265.2	+14.6	yes	0	11.6	15.3	16.2	+16.2
Central Kings GSA	Kings	Sep 25	Sep 26	101.9	99.3–104.3	103.3	−1.4	yes	6	1.1	1.7	1.0	+0.5
James GSA	Kings	Sep 25	Sep 26	150.5	135.6–163.9	141.0	+9.5	yes	3	4.4	6.9	6.3	+6.3
Kings River East GSA	Kings	Sep 25	Sep 26	72.5	68.7–76.0	69.0	+3.5	yes	0	1.9	2.4	2.8	+1.6
McMullin Area GSA	Kings	Sep 25	Sep 26	181.5	170.9–191.0	173.0	+8.5	yes	3	2.8	4.9	6.2	+6.2
North Fork Kings GSA	Kings	Sep 25	Sep 26	191.9	182.3–200.5	187.7	+4.2	yes	0	4.3	5.1	3.5	+2.1
North Kings GSA	Kings	Sep 25	Sep 26	104.5	101.7–107.0	104.0	+0.5	yes	0	1.2	1.8	1.0	+0.8
South Kings GSA	Kings	Sep 25	Sep 26	71.6	68.4–74.5	72.2	−0.6	yes	0	1.2	2.1	1.8	+1.7
Tehama County Flood Control and Water Conservation District GSA	Los Molinos	Sep 25	Sep 26	77.1	75.0–79.0	78.1	−1.0	yes	7	0.8	1.1	1.6	−1.6
City of Madera GSA	Madera	Sep 25	Sep 26	263.3	251.1–274.3	271.5	−8.2	yes	0	5.9	7.0	4.7	−4.6
County of Madera GSA - Madera	Madera	Sep 25	Sep 26	265.8	229.0–299.0	276.5	−10.7	yes	0	5.1	7.8	13.2	−13.2
Gravelly Ford Water District GSA	Madera	Sep 25	Sep 26	148.9	142.8–154.4	146.1	+2.8	yes	0	2.6	3.5	3.3	+3.3
Madera Irrigation District GSA	Madera	Sep 25	Sep 26	224.5	219.6–228.9	229.7	−5.2	no	0	2.3	1.7	3.6	−3.6
Madera Water District GSA	Madera	Sep 25	Sep 26	372.2	363.7–379.9	370.9	+1.3	yes	0	4.2	4.6	4.6	−3.6
New Stone Water District GSA	Madera	Sep 25	Sep 26	155.5	150.2–160.2	153.4	+2.1	yes	0	2.6	3.7	1.9	+1.6
Root Creek Water District GSA	Madera	Sep 25	Sep 26	210.1	198.9–220.2	221.9	−11.8	no	0	3.7	7.5	12.6	−11.9
Merced Irrigation-Urban GSA	Merced	Sep 25	Sep 26	100.7	95.2–105.6	97.9	+2.8	yes	0	2.3	3.2	2.9	+2.9
Merced Subbasin GSA	Merced	Sep 25	Sep 26	119.5	111.0–127.2	114.6	+4.9	yes	0	3.7	5.3	4.8	+4.8
Turner Island Water District GSA - Merced	Merced	Sep 25	Sep 26	44.7	36.2–52.4	51.6	−6.9	yes	0	3.1	5.5	3.9	−3.3
County of Tuolumne GSA	Modesto	Mar 25	Mar 26	144.3	134.8–152.9	145.6	−1.3	yes	0	1.8	7.5	1.3	−1.3
Stanislaus and Tuolumne Rivers Groundwater Basin Association GSA	Modesto	Sep 25	Sep 26	99.0	95.6–102.1	98.1	+0.9	yes	0	1.2	2.0	2.0	+1.8
County of Sutter GSA - North American	North American	Sep 25	Sep 26	25.5	22.9–27.9	26.3	−0.8	yes	0	1.0	1.0	1.3	−1.2
Reclamation District No. 1001 GSA	North American	Sep 25	Sep 26	13.2	10.4–15.7	14.7	−1.5	yes	4	0.7	1.1	1.1	−1.1
Sacramento Groundwater Authority GSA	North American	Sep 25	Sep 26	75.7	73.6–77.6	74.9	+0.8	yes	6	0.7	0.7	0.6	+0.6
South Sutter Water District GSA	North American	Sep 25	Sep 26	44.1	40.1–47.7	42.4	+1.7	yes	2	1.3	2.1	2.6	−0.4
West Placer GSA	North American	Sep 25	Sep 26	73.9	71.8–75.8	71.5	+2.4	no	1	0.9	1.3	1.6	+1.2
City of Marysville GSA	North Yuba	Sep 25	Sep 26	24.5	20.3–28.3	20.4	+4.1	yes	0	1.8	2.3	1.7	+1.6
Cordua Irrigation District GSA	North Yuba	Sep 25	Sep 26	24.7	21.9–27.2	23.4	+1.3	yes	1	1.2	1.4	1.7	+1.6
Yuba Water Agency GSA - North Yuba	North Yuba	Sep 25	Sep 26	25.9	23.7–27.9	23.6	+2.3	no	1	1.1	1.3	1.6	+1.2
City of Coalinga GSA	Pleasant Valley	Sep 25	Sep 26	413.3	385.0–438.8	428.6	−15.3	yes	0	16.0	17.9	31.1	−31.1
County of Fresno GSA - Pleasant Valley	Pleasant Valley	Sep 25	Sep 26	444.4	396.5–487.5	470.2	−25.8	yes	0	26.1	28.4	50.6	−50.6
Pleasant Valley GSA	Pleasant Valley	Sep 25	Sep 26	403.9	389.2–417.1	419.9	−16.0	no	0	14.6	13.3	22.4	−22.4
Tehama County Flood Control and Water Conservation District GSA	Red Bluff	Sep 25	Sep 26	84.8	81.6–87.7	85.6	−0.8	yes	10	1.2	1.4	2.1	−2.1
City of Vacaville GSA	Solano	Sep 25	Sep 26	134.3	131.5–136.8	135.3	−1.0	yes	0	1.3	1.5	0.9	−0.6
Reclamation District No. 349 GSA	Solano	Sep 25	Sep 26	10.9	4.4–16.8	15.1	−4.2	yes	0	2.6	3.2	3.6	+0.1
Reclamation District No. 501 GSA - Northern Delta GSA	Solano	Sep 25	Sep 26	10.4	2.8–17.3	15.2	−4.8	yes	0	2.8	3.3	3.3	+0.2
Sacramento County GSA - Solano	Solano	Sep 25	Sep 26	10.9	7.1–14.4	13.6	−2.7	yes	1	1.6	2.1	1.7	−0.1
Solano Irrigation District GSA	Solano	Sep 25	Sep 26	85.4	80.7–89.6	91.4	−6.0	no	3	1.5	2.6	3.7	−3.7
Solano Subbasin GSA	Solano	Sep 25	Sep 26	34.4	31.6–36.9	37.1	−2.7	no	7	0.9	1.5	1.4	−0.8
County of Sacramento GSA - South American	South American	Sep 25	Sep 26	15.7	13.6–17.6	16.0	−0.3	yes	0	0.6	0.7	0.3	+0.1
Franklin Drainage District GSA - Northern Delta GSA	South American	Sep 25	Sep 26	15.3	12.9–17.5	17.3	−2.0	yes	0	1.1	1.4	0.9	−0.3
Omochumne-Hartnell Water District GSA - South American	South American	Sep 25	Sep 26	77.4	71.1–83.1	72.9	+4.5	yes	2	2.0	3.1	3.6	+3.6
Reclamation District No. 1002 GSA - Northern Delta GSA	South American	Sep 25	Sep 26	17.2	15.1–19.1	17.3	−0.1	yes	0	0.7	1.1	0.6	−0.3
Reclamation District No. 2110 GSA - Northern Delta GSA	South American	Sep 25	Sep 26	10.2	8.1–12.1	10.3	−0.1	yes	0	0.5	0.7	0.5	−0.3
Reclamation District No. 369 GSA - Northern Delta GSA	South American	Sep 25	Sep 26	7.6	5.5–9.5	8.1	−0.5	yes	0	0.7	1.0	0.6	−0.6
Reclamation District No. 551 GSA	South American	Sep 25	Sep 26	9.7	6.5–12.6	12.3	−2.6	yes	0	1.5	1.8	1.4	−0.1
Reclamation District No. 744 GSA - Northern Delta GSA	South American	Sep 25	Sep 26	12.8	10.4–15.0	14.9	−2.1	yes	0	1.0	1.3	1.0	−0.5
Reclamation District No. 813 GSA - Northern Delta GSA	South American	Sep 25	Sep 26	16.4	14.0–18.6	18.5	−2.1	yes	0	1.3	1.8	1.0	−0.2
Sacramento Central Groundwater Authority GSA - 1	South American	Sep 25	Sep 26	70.7	66.7–74.3	68.5	+2.2	yes	7	1.6	2.0	2.3	+2.3
Yuba Water Agency GSA - South Yuba	South Yuba	Sep 25	Sep 26	28.8	25.2–32.1	27.0	+1.8	yes	9	1.3	1.7	2.2	+2.2
Butte Water District GSA - Sutter	Sutter	Sep 25	Sep 26	19.7	17.5–21.7	13.2	+6.5	no	0	1.6	2.5	3.4	+3.3
City of Live Oak GSA	Sutter	Sep 25	Sep 26	22.8	20.0–25.3	16.8	+6.0	no	0	2.1	2.4	3.2	+2.9
City of Yuba City GSA	Sutter	Sep 25	Sep 26	24.6	18.7–29.9	20.3	+4.3	yes	0	2.0	3.3	3.2	+3.2
County of Sutter GSA - Sutter	Sutter	Sep 25	Sep 26	14.3	12.2–16.2	13.3	+1.0	yes	5	0.5	0.8	1.1	+1.0
Reclamation District No. 1500 GSA	Sutter	Sep 25	Sep 26	9.4	6.8–11.8	11.3	−1.9	yes	0	0.8	1.3	1.1	−1.1
Reclamation District No. 1660 GSA	Sutter	Sep 25	Sep 26	7.0	4.9–8.9	8.8	−1.8	yes	0	0.7	0.8	0.7	−0.6
Reclamation District No. 70 GSA	Sutter	Sep 25	Sep 26	12.8	8.8–16.4	10.8	+2.0	yes	0	1.8	2.9	1.7	+1.7
Sutter Community Service District GSA	Sutter	Sep 25	Sep 26	7.7	4.5–10.6	8.8	−1.1	yes	0	0.9	1.6	2.6	+2.4
Sutter Extension Water District GSA	Sutter	Sep 25	Sep 26	9.6	7.0–12.0	9.6	+0.0	yes	9	0.8	1.3	2.3	+2.3
Banta-Carbona Irrigation District GSA	Tracy	Sep 25	Sep 26	111.1	103.0–118.4	105.2	+5.9	yes	9	3.8	4.1	4.0	+3.0
Byron-Bethany Irrigation District GSA - Tracy	Tracy	Sep 25	Sep 26	90.9	81.5–99.3	68.9	+22.0	no	4	3.2	9.4	20.2	+20.2
City of Lathrop GSA	Tracy	Sep 25	Sep 26	17.7	15.6–19.6	17.0	+0.7	yes	1	0.7	1.0	1.6	+1.6
City of Tracy GSA	Tracy	Sep 25	Sep 26	134.1	124.3–142.9	125.3	+8.8	yes	1	3.8	5.7	8.0	+4.6
County of San Joaquin GSA - Tracy	Tracy	Sep 25	Sep 26	48.9	43.3–53.9	44.2	+4.7	yes	4	1.7	2.5	4.1	+3.9
Stewart Tract GSA	Tracy	Sep 25	Sep 26	21.0	18.9–22.9	20.3	+0.7	yes	1	0.6	0.8	0.9	+0.9
El Rico GSA	Tulare Lake	Sep 25	Sep 26	249.5	213.7–281.8	228.7	+20.8	yes	0	41.8	28.7	20.2	+20.2
Mid-Kings River GSA	Tulare Lake	Sep 25	Sep 26	151.6	144.3–158.2	146.8	+4.8	yes	0	4.4	4.2	4.2	+2.8
South Fork Kings GSA	Tulare Lake	Sep 25	Sep 26	208.1	182.8–230.9	200.3	+7.8	yes	0	18.6	14.7	7.1	+7.1
Southwest Kings GSA	Tulare Lake	Sep 25	Sep 26	207.2	183.4–228.6	233.1	−25.9	no	0	8.5	15.0	17.9	−14.2
Tri-County Water Authority GSA - Tulare Lake	Tulare Lake	Sep 25	Sep 26	244.3	202.1–282.3	213.5	+30.8	yes	0	28.2	27.7	34.1	+34.1
Alpaugh GSA	Tule	Sep 25	Sep 26	279.4	261.5–295.6	242.0	+37.4	no	0	50.1	38.1	41.6	+41.6
County of Tulare GSA - Tule	Tule	Sep 25	Sep 26	207.1	86.8–315.5	258.8	−51.7	yes	0	34.7	59.1	69.4	−69.4
Delano-Earlimart Irrigation District GSA	Tule	Sep 25	Sep 26	273.7	264.8–281.8	273.2	+0.5	yes	0	6.7	3.4	3.5	−1.4
Kern-Tulare Water District GSA - Tule	Tule	Sep 25	Sep 26	451.2	414.9–483.9	406.2	+45.0	no	0	14.5	20.0	20.4	+20.4
Lower Tule River Irrigation District GSA	Tule	Sep 25	Sep 26	168.3	160.2–175.6	175.3	−7.0	yes	3	5.3	4.1	4.2	−1.6
Pixley Irrigation District GSA	Tule	Sep 25	Sep 26	242.3	230.3–253.1	250.8	−8.5	yes	2	5.6	5.7	6.7	−6.6
Porterville Irrigation District GSA	Tule	Sep 25	Sep 26	86.4	60.1–110.1	75.0	+11.4	yes	0	13.7	13.9	13.4	+13.4
Saucelito Irrigation District GSA	Tule	Sep 25	Sep 26	211.5	181.5–238.5	201.2	+10.3	yes	0	14.0	14.7	14.3	+14.3
Tea Pot Dome Water District GSA	Tule	Sep 25	Sep 26	86.5	46.1–122.9	71.9	+14.6	yes	0	19.9	18.4	19.8	+19.8
Terra Bella Irrigation District GSA	Tule	Sep 25	Sep 26	178.5	84.1–263.5	141.1	+37.4	yes	0	50.6	45.4	47.4	+47.4
Tri-County Water Authority GSA - Tule	Tule	Sep 25	Sep 26	255.5	242.6–267.2	225.3	+30.2	no	0	37.8	27.7	24.0	+24.0
Tule East GSA JPA	Tule	Sep 25	Sep 26	293.5	181.0–394.9	245.8	+47.7	yes	0	55.8	55.2	54.4	+54.4
Vandalia Water District GSA	Tule	Sep 25	Sep 26	69.6	39.9–96.3	60.8	+8.8	yes	1	14.1	13.1	14.5	+14.5
East Turlock Subbasin GSA	Turlock	Sep 25	Sep 26	169.9	159.1–179.6	164.9	+5.0	yes	9	4.6	7.1	7.6	+7.6
West Turlock Subbasin GSA	Turlock	Sep 25	Sep 26	53.4	47.9–58.3	50.3	+3.1	yes	0	2.4	2.8	3.1	+3.1
Rock Creek Reclamation District GSA	Vina	Sep 25	Sep 26	36.9	32.7–40.7	34.8	+2.1	yes	0	1.8	2.2	2.4	+2.0
Vina GSA	Vina	Sep 25	Sep 26	63.3	57.6–68.4	60.7	+2.6	yes	9	1.8	2.5	3.1	−2.7
County of Fresno GSA - Westside	Westside	Sep 25	Sep 26	458.5	401.1–510.2	387.9	+70.6	no	0	53.1	64.3	59.3	+59.3
Westlands Water District GSA	Westside	Sep 25	Sep 26	285.0	258.4–309.0	263.5	+21.5	yes	0	25.2	26.4	19.7	+19.7
White Wolf GSA	White Wolf	Sep 25	Sep 26	505.7	496.5–513.9	508.9	−3.2	yes	0	7.4	6.3	8.2	−8.2
Wyandotte Creek GSA	Wyandotte Creek	Sep 25	Sep 26	53.8	51.4–56.0	54.5	−0.7	yes	3	1.4	1.4	1.2	−0.8
Yolo Subbasin GSA	Yolo	Sep 25	Sep 26	60.9	57.9–63.6	62.3	−1.4	yes	35	1.2	2.2	0.8	+0.0

By subbasin

Subbasin	Region	Made	For	Forecast	80 % range	Actual	Miss	Inside	Wells read	Typical miss 1 mo	6 mo	12 mo	Bias 12 mo
Antelope	Sacramento Valley	Sep 25	Sep 26	39.2	36.4–41.7	41.0	−1.8	yes	5	1.0	1.4	1.5	−0.3
Bend	Sacramento Valley	Sep 25	Sep 26	42.9	36.0–49.2	46.0	−3.1	yes	0	2.6	3.7	3.9	−3.9
Butte	Sacramento Valley	Sep 25	Sep 26	12.0	9.7–14.0	13.1	−1.1	yes	17	0.5	0.7	0.6	−0.3
Chowchilla	Friant east side	Sep 25	Sep 26	210.2	203.5–216.3	209.4	+0.8	yes	0	3.1	3.2	3.1	−2.0
Colusa	Sacramento Valley	Sep 25	Sep 26	70.3	65.1–75.0	75.8	−5.5	no	91	1.9	2.8	3.6	−3.6
Corning	Sacramento Valley	Sep 25	Sep 26	110.9	107.0–114.4	108.3	+2.6	yes	48	1.7	1.7	1.7	+1.5
Cosumnes	Northern and eastern San Joaquin	Sep 25	Sep 26	105.8	99.1–111.9	98.3	+7.5	no	6	1.9	4.6	5.2	+5.2
Delta-Mendota	Westside (CVP south of Delta)	Sep 25	Sep 26	89.5	84.5–94.0	88.3	+1.2	yes	5	2.1	2.7	1.8	+1.8
East Contra Costa	Northern and eastern San Joaquin	Sep 25	Sep 26	18.7	15.9–21.2	21.0	−2.3	yes	0	0.9	1.2	1.3	−1.3
Eastern San Joaquin	Northern and eastern San Joaquin	Sep 25	Sep 26	101.0	95.8–105.7	99.2	+1.8	yes	20	1.7	3.0	4.5	+4.5
Kaweah	Friant east side	Sep 25	Sep 26	126.8	119.4–133.5	124.2	+2.6	yes	15	3.9	4.0	2.8	+2.8
Kern County	Kern and Tulare Lake (SWP)	Sep 25	Sep 26	285.1	275.0–294.2	281.9	+3.2	yes	0	3.2	7.0	6.3	+6.3
Kings	Friant east side	Sep 25	Sep 26	123.5	118.1–128.4	120.9	+2.6	yes	12	1.8	2.7	2.0	+1.9
Los Molinos	Sacramento Valley	Sep 25	Sep 26	77.1	74.8–79.1	78.1	−1.0	yes	7	0.8	1.1	1.6	−1.6
Madera	Friant east side	Sep 25	Sep 26	245.2	222.7–265.5	252.7	−7.5	yes	0	3.2	4.0	8.2	−8.2
Merced	Northern and eastern San Joaquin	Sep 25	Sep 26	108.5	103.3–113.2	107.2	+1.3	yes	0	2.4	3.2	2.3	+2.3
Modesto	Northern and eastern San Joaquin	Sep 25	Sep 26	99.1	95.5–102.4	98.1	+1.0	yes	0	1.2	2.0	1.9	+1.7
North American	Sacramento Valley	Sep 25	Sep 26	62.7	60.4–64.7	61.4	+1.3	yes	13	0.6	0.8	1.1	+0.4
North Yuba	Sacramento Valley	Sep 25	Sep 26	25.9	23.6–28.0	23.6	+2.3	yes	1	1.2	1.3	1.6	+1.2
Pleasant Valley	Westside (CVP south of Delta)	Sep 25	Sep 26	412.2	389.7–432.5	430.2	−18.0	yes	0	16.5	17.2	28.6	−28.6
Red Bluff	Sacramento Valley	Sep 25	Sep 26	84.8	81.4–87.9	85.6	−0.8	yes	10	1.2	1.4	2.1	−2.1
Solano	Sacramento Valley	Sep 25	Sep 26	39.3	36.1–42.2	42.4	−3.1	no	11	1.1	1.7	1.4	−1.0
South American	Sacramento Valley	Sep 25	Sep 26	65.8	62.2–69.1	64.0	+1.8	yes	10	1.4	1.7	2.0	+2.0
South Yuba	Sacramento Valley	Sep 25	Sep 26	28.8	24.9–32.3	27.0	+1.8	yes	9	1.3	1.7	2.2	+2.2
Sutter	Sacramento Valley	Sep 25	Sep 26	12.9	10.6–14.9	12.3	+0.6	yes	14	0.5	0.7	0.9	+0.8
Tracy	Westside (CVP south of Delta)	Sep 25	Sep 26	62.2	57.5–66.5	55.8	+6.4	no	20	1.4	2.7	4.6	+4.1
Tulare Lake	Kern and Tulare Lake (SWP)	Sep 25	Sep 26	214.5	197.5–229.9	205.8	+8.7	yes	0	19.9	13.6	8.5	+8.5
Tule	Friant east side	Sep 25	Sep 26	233.4	220.8–244.8	221.8	+11.6	yes	6	6.9	8.0	8.0	+5.6
Turlock	Northern and eastern San Joaquin	Sep 25	Sep 26	98.9	90.7–106.4	95.1	+3.8	yes	9	3.3	4.5	4.8	+4.8
Vina	Sacramento Valley	Sep 25	Sep 26	62.8	57.2–67.9	60.0	+2.8	yes	9	1.7	2.4	2.9	−2.4
Westside	Westside (CVP south of Delta)	Sep 25	Sep 26	285.3	261.5–306.8	265.2	+20.1	yes	0	23.0	24.0	17.7	+17.7
White Wolf	Kern and Tulare Lake (SWP)	Sep 25	Sep 26	505.3	495.3–514.3	508.9	−3.6	yes	0	7.5	6.4	8.5	−8.5
Wyandotte Creek	Sacramento Valley	Sep 25	Sep 26	53.8	51.3–56.1	54.5	−0.7	yes	3	1.4	1.4	1.2	−0.9
Yolo	Sacramento Valley	Sep 25	Sep 26	60.7	57.5–63.6	62.3	−1.6	yes	35	1.3	2.2	0.8	−0.2

Live record: what the site published

Each month the map publishes a forecast under NOAA's outlook. It is frozen at publication and scored here as the readings for its months come in.

The first edition (Sep 2026 readings) is scored as readings arrive: 1 month ahead with the Oct 2026 readings; 6 months ahead with the Mar 2027 readings; 12 months ahead with the Sep 2027 readings. The page fills in at each monthly refresh.

Monthly editions

Hits at the longest lead scored so far. Bar: share of GSAs inside their 80 % range. Orange outline: the model was retrained before that edition.

Sep 26not yet

Cite

Gray, W. (2026). Central Valley Groundwater Map and Forecast, release 2026-09.5cdfad9c (readings through Sep 2026) [Data set]. CC BY 4.0. https://groundwater-map-175591637760.us-west1.run.app/release/2026-09.5cdfad9c

Built 2026-10-29 22:43. Central Valley Groundwater Map and Forecast (Gray, W.). CC BY-NC 4.0: the CSV has every scored month.