California El Nino and La Nina Precipitation Climatology

This is a catalog of California precipitation anomalies for previous la Niña events based upon their strength and the 10 state hydrologic regions. It has the average for all events, weak events, moderate events, strong and very strong events and the wide range of the individual seasons that went into making up each of the averages.

It cannot be stressed strongly enough that this is a climatological analysis and NOT a forecasting tool. This is especially true for the averages of different strength events which are made up of what are a very broad range of conditions; some that are decidedly atypical.

The Oceanic Niño Index (ONI) is used to identify El Niño (warm) and La Niña (cool) events in the tropical Pacific. The ONI is the running 3-month mean SST anomaly for the Niño 3.4 region (i.e., 5°N-5°S, 120°-170°W). Events are defined as 5 consecutive months at or above the +0.5° anomaly for warm (El Niño) events and at or below the -0.5 anomaly for cold (La Niña) events. The threshold is further broken down into Weak (with a 0.5° to 0.9° SST anomaly), Moderate (1.0° to 1.4°), Strong (1.5° to 1.9°) and Very Strong (≥ 2.0°) events. For the purpose of this report for an event to be weak, moderate, strong or very strong it much have equaled or exceeded the threshold for at least 3 months.

La Niña Events:
     Weak: 1954-55, 1964-65, 1971-72, 1974-75, 1983-84, 1984-85, 2000-01, 2005-06, 2008-09, 2016-17, 2017-18, 2022-23
     Moderate: 1955-56, 1970-71, 1995-96, 2011-12, 2020-21, 2021-2022
     Strong: 1973-74, 1975-76, 1988-89, 1998-99, 1999-00, 2007-08, 2010-11

ALL La Niña Events

		Table 1. All La Niña Events - Average Percent of Normal Seasonal Precipitation (25 events)
ENSO Type	N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
All La NIña	102%	98%	103%	95%	99%	91%	95%	89%	84%	80%	97%
Weak La NIña	101%	100%	108%	100%	107%	97%	102%	102%	90%	95%	101%
Moderate La NIña	102%	93%	101%	92%	89%	81%	83%	65%	71%	52%	90%
Strong La NIña	105%	98%	97%	91%	95%	90%	94%	86%	84%	77%	96%

All La NIña		Table 2. All La Niña - Years by Percent of Normal Categories (25 events)
% of Normal	N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
<80%	7	10	6	10	10	10	9	12	13	15	10
80-100%	6	3	6	6	4	5	8	7	9	5	5
100-120%	4	5	6	2	5	7	3	2	0	2	4
120-140%	5	5	3	5	3	1	2	1	1	1	5
>140%	3	2	4	2	3	2	3	2	2	2	1

Average - ALL La Niña
ONI ≤ -0.5

1954-55	1955-56	1964-65	1970-71

1971-72	1973-74	1974-75	1975-76

1983-84	1984-85	1988-89	1995-96

1998-99	1999-00	2000-01	2005-06

2007-08	2008-09	2010-11	2011-12

2016-17	2017-18	2020-21	2021-2022

2022-23

WEAK La Niña Events

Weak La NIña		Table 3. Weak La Niña - Years by Percent of Normal Categories (12 events)
% of Normal	N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
<80%	4	5	2	5	4	5	3	3	5	5	5
80-100%	2	2	4	3	2	2	5	4	5	3	2
100-120%	2	2	2	1	2	3	1	2	0	1	2
120-140%	3	1	2	1	2	0	1	1	1	1	2
>140%	1	2	2	2	2	2	2	2	1	2	1

Average - WEAK El Niño
ONI ≤ -0.5 to -0.9

1954-55	1964-65	1971-72	1974-75

1983-84	1984-85	2000-01	2005-06

2008-09	2016-17	2017-18	2022-23

MODERATE La Niña Events

Moderate La NIña		Table 4. Moderate La Niña - Years by Percent of Normal Categories (6 events)
% of Normal	N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
<80%	2	3	2	2	3	3	3	5	4	6	3
80-100%	1	0	0	2	1	1	1	1	2	0	0
100-120%	0	1	2	0	1	2	1	0	0	0	2
120-140%	2	2	1	2	1	0	1	0	0	0	1
>140%	1	0	1	0	0	0	0	0	0	0	0

Average - MODERATE El Niño
ONI ≤ -1.0 to 1.5

1955-56	1970-71	1995-96	2011-12

2020-21	2021-2022

STRONG La Niña Events

Strong La NIña		Table 5. Strong La Niña - Years by Percent of Normal Categories (7 events)
% of Normal	N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
<80%	1	2	2	3	3	2	3	4	4	4	2
80-100%	3	1	2	1	1	2	2	2	2	2	3
100-120%	2	2	2	1	2	2	1	0	0	1	0
120-140%	0	2	0	2	0	1	0	0	0	0	2
>140%	1	0	1	0	1	0	1	1	1	0	0

Average - STRONG El Niño
ONI ≤ -1.5 TO -2.0

1973-74	1975-76	1988-89	1998-99

1999-00	2007-08	2010-11

Table 6. Percent of Normal (1991-2020) California Rainfall for All ENSO Types

Normal 52.80 36.33 19.45 25.28 27.45 19.96 15.86 6.94 17.39 5.11 23.61

ENSO Type Rain Season N Coast Sacramento N Lahontan SF Bay S Joaquin C Coast Tulare Lk S Lahontan S Coast Colo River CALIFORNIA

1950 - 1951 110% 109% 115% 105% 118% 73% 94% 66% 54% 49% 106%

Mod. El Niño 1951 - 1952 118% 126% 131% 130% 129% 136% 136% 138% 161% 151% 134%

Weak El Niño 1952 - 1953 115% 101% 97% 92% 82% 75% 83% 67% 70% 74% 100%

Weak El Niño 1953 - 1954 106% 90% 79% 74% 81% 76% 83% 75% 90% 72% 94%

Weak La Niña 1954 - 1955 71% 67% 65% 70% 75% 78% 79% 67% 73% 65% 74%

Mod. La Niña 1955 - 1956 138% 132% 139% 130% 130% 109% 117% 79% 80% 62% 130%

1956 - 1957 89% 82% 89% 73% 80% 71% 78% 67% 77% 52% 85%

Stg. El Niño 1957 - 1958 146% 140% 126% 151% 131% 159% 142% 121% 156% 127% 147%

Weak El Niño 1958 - 1959 80% 69% 71% 56% 61% 62% 53% 56% 50% 52% 70%

1959 - 1960 87% 80% 70% 74% 74% 70% 68% 64% 68% 95% 82%

1960 - 1961 97% 78% 67% 64% 61% 53% 58% 55% 37% 47% 77%

1961 - 1962 80% 85% 95% 81% 93% 106% 106% 98% 111% 74% 93%

1962 - 1963 115% 119% 132% 120% 109% 102% 96% 69% 53% 42% 112%

Mod. El Niño 1963 - 1964 80% 67% 81% 61% 69% 62% 72% 75% 76% 90% 76%

Weak La Niña 1964 - 1965 116% 110% 118% 101% 116% 94% 103% 86% 79% 78% 112%

Stg. El Niño 1965 - 1966 88% 73% 78% 73% 73% 78% 73% 104% 117% 116% 86%

1966 - 1967 107% 120% 131% 134% 133% 133% 142% 102% 130% 72% 124%

1967 - 1968 78% 75% 78% 70% 65% 61% 66% 84% 77% 97% 78%

Mod. El Niño 1968 - 1969 120% 127% 142% 126% 153% 168% 180% 150% 174% 104% 143%

Weak El Niño 1969 - 1970 110% 110% 111% 99% 96% 74% 77% 57% 59% 73% 102%

Mod. La Niña 1970 - 1971 118% 103% 116% 92% 87% 78% 82% 72% 77% 55% 103%

Weak La Niña 1971 - 1972 95% 68% 79% 51% 64% 48% 52% 57% 51% 58% 75%

Stg. El Niño 1972 - 1973 90% 107% 97% 135% 111% 139% 129% 118% 120% 111% 112%

Stg. La Niña 1973 - 1974 150% 134% 110% 122% 109% 107% 98% 69% 78% 57% 128%

Weak La Niña 1974 - 1975 100% 95% 98% 92% 101% 95% 91% 84% 86% 63% 99%

Stg. La Niña 1975 - 1976 68% 49% 57% 39% 49% 43% 56% 67% 61% 77% 60%

Weak El Niño 1976 - 1977 41% 43% 69% 46% 47% 66% 63% 102% 84% 112% 56%

Weak El Niño 1977 - 1978 128% 133% 120% 134% 140% 169% 170% 190% 212% 199% 151%

1978 - 1979 73% 80% 80% 83% 97% 97% 101% 116% 129% 143% 92%

Weak El Niño 1979 - 1980 107% 114% 130% 120% 121% 123% 127% 152% 178% 192% 128%

1980 - 1981 74% 74% 77% 65% 69% 75% 73% 73% 60% 65% 75%

1981 - 1982 143% 145% 146% 157% 149% 118% 124% 110% 103% 91% 143%

V. Stg. El Niño 1982 - 1983 155% 163% 159% 187% 180% 196% 186% 190% 195% 187% 177%

Weak La Niña 1983 - 1984 117% 108% 118% 93% 104% 74% 88% 98% 70% 134% 110%

Weak La Niña 1984 - 1985 78% 70% 80% 79% 73% 70% 80% 128% 83% 146% 83%

1985 - 1986 111% 126% 140% 131% 131% 119% 130% 110% 117% 110% 127%

Mod. El Niño 1986 - 1987 78% 64% 66% 58% 58% 61% 67% 81% 62% 87% 72%

Stg. El Niño 1987 - 1988 78% 72% 62% 67% 63% 75% 79% 101% 95% 116% 80%

Stg. La Niña 1988 - 1989 89% 86% 95% 66% 71% 54% 71% 64% 60% 62% 83%

1989 - 1990 74% 76% 76% 64% 73% 54% 63% 50% 56% 45% 73%

1990 - 1991 63% 67% 78% 66% 72% 87% 81% 94% 95% 113% 76%

Stg. El Niño 1991 - 1992 67% 71% 62% 81% 71% 98% 77% 132% 123% 164% 83%

1992 - 1993 118% 125% 123% 123% 131% 145% 136% 160% 206% 213% 139%

1993 - 1994 62% 63% 64% 65% 60% 70% 71% 53% 73% 65% 66%

Mod. El Niño 1994 - 1995 139% 161% 162% 150% 156% 176% 161% 145% 174% 137% 160%

Mod. La Niña 1995 - 1996 119% 115% 124% 119% 109% 97% 98% 67% 71% 32% 112%

1996 - 1997 119% 117% 132% 104% 123% 107% 120% 79% 86% 49% 118%

V. Stg. El Niño 1997 - 1998 145% 158% 128% 173% 152% 203% 179% 180% 198% 169% 166%

Stg. La Niña 1998 - 1999 111% 96% 109% 90% 89% 80% 79% 74% 54% 60% 98%

Stg. La Niña 1999 - 2000 93% 97% 86% 98% 100% 100% 90% 70% 69% 54% 96%

Weak La Niña 2000 - 2001 58% 65% 54% 72% 75% 103% 81% 89% 89% 82% 73%

2001 - 2002 93% 86% 76% 89% 82% 63% 76% 41% 32% 25% 82%

Mod. El Niño 2002 - 2003 111% 104% 90% 103% 89% 96% 94% 92% 105% 76% 106%

2003 - 2004 92% 90% 82% 81% 73% 66% 71% 87% 60% 93% 88%

Weak El Niño 2004 - 2005 98% 108% 108% 122% 130% 151% 132% 187% 209% 212% 129%

Weak La Niña 2005 - 2006 135% 138% 135% 134% 129% 111% 119% 99% 86% 72% 132%

Weak El Niño 2006 - 2007 78% 61% 57% 56% 56% 40% 48% 35% 29% 30% 62%

Stg. La Niña 2007 - 2008 83% 70% 73% 74% 71% 83% 72% 81% 88% 82% 80%

Weak La Niña 2008 - 2009 75% 79% 81% 76% 83% 64% 71% 74% 66% 83% 80%

Mod. El Niño 2009 - 2010 102% 95% 90% 107% 103% 111% 108% 99% 109% 117% 106%

Stg. La Niña 2010 - 2011 115% 124% 141% 118% 145% 130% 147% 129% 136% 96% 132%

Mod. La Niña 2011 - 2012 87% 71% 62% 67% 62% 61% 65% 52% 64% 61% 75%

2012 - 2013 83% 78% 83% 71% 67% 54% 47% 53% 48% 78% 75%

2013 - 2014 57% 56% 65% 53% 50% 39% 43% 54% 45% 63% 56%

Weak El Niño 2014 - 2015 82% 74% 84% 79% 57% 59% 51% 65% 58% 86% 75%

V. Stg. El Niño 2015 - 2016 112% 104% 121% 95% 103% 82% 98% 96% 72% 74% 107%

Weak La Niña 2016 - 2017 150% 156% 185% 159% 168% 138% 146% 134% 115% 115% 158%

Weak La Niña 2017 - 2018 75% 76% 108% 69% 77% 61% 65% 60% 43% 37% 74%

Weak El Niño 2018 - 2019 113% 130% 132% 134% 127% 127% 132% 141% 139% 140% 125%

2019 - 2020 64% 63% 75% 57% 66% 82% 78% 100% 112% 147% 72%

Mod. La Niña 2020 - 2021 57% 44% 59% 39% 50% 51% 44% 31% 39% 25% 48%

Mod. La Niña 2021 - 2022 75% 76% 100% 82% 72% 69% 63% 67% 70% 54% 73%

Weak La Niña 2022 2023 106% 127% 157% 155% 169% 183% 184% 161% 177% 119% 138%

Stg. El Niño 2023 2024 110% 96% 92% 102% 94% 123% 103% 138% 139% 122% 106%

ENSO Type Rain Season N Coast Sacramento N Lahontan SF Bay S Joaquin C Coast Tulare Lk S Lahontan S Coast Colo River CALIFORNIA


Table 7. Percent of Normal (1991-2020) California Rainfall - Sorted by ENSO Type
			Normal	52.66	36.01	19.32	25.03	27.22	19.70	15.64	6.77	17.04	4.95	23.61
ENSO Type	Rain Season			N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
Weak El Niño	1952	-	1953	119%	105%	98%	96%	86%	79%	89%	72%	74%	79%	100%
Weak El Niño	1953	-	1954	110%	93%	80%	77%	85%	80%	88%	80%	95%	77%	94%
Weak El Niño	1958	-	1959	83%	71%	72%	59%	64%	65%	57%	60%	53%	56%	70%
Weak El Niño	1969	-	1970	114%	114%	113%	104%	100%	77%	82%	61%	63%	78%	102%
Weak El Niño	1976	-	1977	43%	44%	70%	48%	49%	69%	67%	109%	89%	121%	56%
Weak El Niño	1977	-	1978	132%	138%	121%	140%	147%	176%	180%	204%	224%	214%	151%
Weak El Niño	1979	-	1980	111%	119%	131%	126%	127%	128%	135%	163%	188%	206%	128%
Weak El Niño	2004	-	2005	102%	112%	109%	127%	136%	157%	141%	201%	221%	227%	129%
Weak El Niño	2006	-	2007	81%	63%	58%	59%	59%	42%	51%	37%	30%	32%	62%
Weak El Niño	2014	-	2015	85%	77%	85%	83%	59%	62%	54%	70%	61%	92%	75%
Weak El Niño	2018	-	2019	113%	129%	131%	133%	127%	126%	130%	138%	136%	136%	125%

Mod. El Niño	1951	-	1952	122%	130%	132%	135%	135%	142%	145%	148%	170%	162%	134%
Mod. El Niño	1963	-	1964	83%	70%	82%	64%	73%	64%	77%	80%	81%	97%	76%
Mod. El Niño	1968	-	1969	125%	132%	144%	132%	160%	176%	191%	161%	184%	112%	143%
Mod. El Niño	1986	-	1987	81%	67%	67%	60%	61%	63%	71%	86%	65%	94%	72%
Mod. El Niño	1994	-	1995	144%	167%	164%	157%	163%	184%	172%	156%	184%	148%	160%
Mod. El Niño	2002	-	2003	116%	108%	91%	107%	93%	100%	100%	99%	111%	82%	106%
Mod. El Niño	2009	-	2010	106%	99%	91%	112%	108%	116%	115%	106%	115%	125%	106%

Stg. El Niño	1957	-	1958	151%	145%	127%	158%	138%	167%	152%	129%	165%	137%	147%
Stg. El Niño	1965	-	1966	91%	76%	79%	76%	76%	81%	77%	112%	124%	124%	86%
Stg. El Niño	1972	-	1973	94%	111%	98%	141%	117%	145%	137%	126%	127%	119%	112%
Stg. El Niño	1987	-	1988	81%	75%	63%	69%	65%	78%	84%	108%	100%	125%	80%
Stg. El Niño	1991	-	1992	69%	73%	63%	84%	74%	102%	81%	141%	130%	176%	83%
Stg. El Niño	2023	-	2024	110%	96%	92%	102%	94%	123%	103%	138%	139%	122%	106%

V. Stg. El Niño	1982	-	1983	161%	169%	160%	195%	189%	205%	198%	203%	207%	201%	177%
V. Stg. El Niño	1997	-	1998	150%	164%	129%	180%	159%	212%	190%	193%	209%	181%	166%
V. Stg. El Niño	2015	-	2016	116%	108%	122%	99%	107%	86%	104%	103%	76%	80%	107%

ENSO Type	Rain Season			N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
Weak La Niña	1954	-	1955	73%	70%	66%	74%	78%	81%	84%	71%	77%	70%	74%
Weak La Niña	1964	-	1965	120%	115%	119%	105%	122%	98%	110%	92%	83%	83%	112%
Weak La Niña	1971	-	1972	99%	71%	80%	53%	67%	50%	56%	61%	54%	62%	75%
Weak La Niña	1974	-	1975	104%	99%	99%	96%	105%	100%	97%	89%	91%	68%	99%
Weak La Niña	1983	-	1984	121%	113%	120%	97%	109%	77%	94%	105%	74%	144%	110%
Weak La Niña	1984	-	1985	81%	73%	80%	82%	76%	73%	85%	137%	88%	156%	83%
Weak La Niña	2000	-	2001	60%	68%	55%	75%	78%	108%	87%	95%	94%	88%	73%
Weak La Niña	2005	-	2006	140%	143%	137%	139%	135%	116%	127%	106%	91%	77%	132%
Weak La Niña	2008	-	2009	78%	82%	82%	79%	87%	67%	75%	79%	70%	90%	80%
Weak La Niña	2016	-	2017	156%	162%	187%	166%	176%	144%	156%	143%	122%	123%	158%
Weak La Niña	2017	-	2018	77%	79%	108%	72%	81%	63%	67%	64%	45%	40%	74%
				106%	127%	158%	155%	169%	183%	183%	159%	178%	115%	138%

Mod. La Niña	1955	-	1956	143%	137%	141%	136%	136%	114%	124%	84%	84%	66%	130%
Mod. La Niña	1970	-	1971	122%	106%	117%	96%	91%	81%	87%	77%	82%	59%	103%
Mod. La Niña	1995	-	1996	123%	119%	126%	124%	114%	101%	105%	72%	76%	35%	112%
Mod. La Niña	2011	-	2012	90%	74%	63%	70%	65%	64%	69%	56%	68%	65%	75%
Mod. La Niña	2020	-	2021	57%	44%	59%	39%	50%	51%	44%	31%	39%	25%	48%
Mod. La Niña	2021	-	2022	75%	77%	99%	82%	72%	68%	64%	63%	69%	52%	73%

Stg. La Niña	1973	-	1974	156%	139%	111%	127%	114%	112%	104%	74%	82%	61%	128%
Stg. La Niña	1975	-	1976	71%	51%	58%	41%	52%	45%	60%	72%	65%	83%	60%
Stg. La Niña	1988	-	1989	92%	89%	96%	69%	74%	57%	75%	68%	63%	66%	83%
Stg. La Niña	1998	-	1999	115%	100%	110%	93%	93%	83%	84%	79%	57%	64%	98%
Stg. La Niña	1999	-	2000	97%	101%	87%	102%	105%	104%	96%	75%	73%	58%	96%
Stg. La Niña	2007	-	2008	86%	73%	74%	77%	74%	87%	77%	86%	93%	87%	80%
Stg. La Niña	2010	-	2011	119%	129%	143%	123%	151%	136%	156%	138%	144%	103%	132%

ENSO Type	Rain Season			N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA
	1950	-	1951	114%	113%	117%	109%	123%	76%	100%	71%	57%	52%	106%
	1956	-	1957	92%	85%	90%	76%	84%	74%	83%	72%	81%	56%	85%
	1959	-	1960	90%	83%	70%	77%	77%	73%	72%	69%	71%	101%	82%
	1960	-	1961	101%	81%	68%	67%	64%	56%	62%	59%	39%	50%	77%
	1961	-	1962	83%	88%	96%	85%	97%	111%	113%	104%	117%	80%	93%
	1962	-	1963	119%	124%	133%	126%	114%	106%	102%	74%	56%	46%	112%
	1966	-	1967	111%	124%	133%	140%	139%	139%	151%	109%	138%	77%	124%
	1967	-	1968	81%	77%	79%	73%	68%	64%	71%	90%	81%	105%	78%
	1978	-	1979	76%	83%	81%	86%	102%	101%	107%	124%	136%	153%	92%
	1980	-	1981	76%	77%	77%	67%	72%	78%	77%	78%	64%	70%	75%
	1981	-	1982	148%	150%	148%	164%	156%	124%	132%	118%	109%	98%	143%
	1985	-	1986	115%	131%	142%	136%	137%	124%	138%	117%	123%	118%	127%
	1989	-	1990	77%	79%	77%	67%	76%	56%	67%	53%	59%	48%	73%
	1990	-	1991	65%	70%	79%	69%	75%	91%	87%	101%	100%	121%	76%
	1992	-	1993	123%	130%	124%	129%	137%	151%	145%	171%	218%	228%	139%
	1993	-	1994	65%	66%	65%	67%	63%	73%	76%	57%	78%	70%	66%
	1996	-	1997	124%	121%	133%	108%	129%	111%	127%	84%	91%	53%	118%
	2001	-	2002	97%	89%	77%	92%	86%	66%	81%	44%	34%	26%	82%
	2003	-	2004	96%	93%	82%	85%	76%	69%	75%	93%	64%	99%	88%
	2012	-	2013	86%	81%	83%	74%	70%	57%	50%	57%	50%	84%	75%
	2013	-	2014	59%	58%	65%	56%	53%	41%	45%	58%	48%	68%	56%
	2019	-	2020	64%	63%	75%	56%	66%	81%	78%	98%	110%	143%	72%
ENSO Type	Rain Season			N Coast	Sacramento	N Lahontan	SF Bay	S Joaquin	C Coast	Tulare Lk	S Lahontan	S Coast	Colo River	CALIFORNIA