El Nino / La Nina Rainfall Comparison

ENSO - El Niño / La Nina Information for Site 004

ENSO (El Niño Southern Oscillation) is the warming and cooling of the ocean water along the Equator in the Eastern Pacific Ocean near South America. The warm phase is called El Niño and the cold phase is called La Nina.

When the Eastern Pacific Ocean is 0.5 degrees Celsius above normal for 5 consecutive 3-month average periods, an El Niño is declared. When the Eastern Pacific Ocean is 0.5 degrees Celsius below normal for 5 consecutive 3-month average periods, a La Nina is declared.

The El Niño and La Nina are declared as Weak, Moderate, or Strong depending on how far from normal the water temperature gets. When the temperature is above 1.5 degrees Celsius, it is declared as strong. When the temperature is above 1.0 degrees Celsius, it is declared as Moderate. When the temperature is above 0.5 degrees Celsius, it is declared as Weak.

The effect on Ventura County trends to be wetter with El Niños and drier with La Ninas. Although the top driest years have been Neutral or Weak or Moderate El Niños.

Data for calculating ENSO Index (ONI) is provided by the Climate Prediction Center.


Strongest El Niños

#Water
Year
IntensitySiteSeason
Total
Percent
Normal
12016+2.5004A - Casitas Dam12.6154.1%
21998+2.3004A - Casitas Dam59.55255.5%
31983+2.1004A - Casitas Dam51.13219.3%
41973+2.0004A - Casitas Dam34.79149.2%
51958+1.7004A - Casitas Dam41.26177.0%
61992+1.6004A - Casitas Dam27.40117.5%
71966+1.5004A - Casitas Dam25.23108.2%

Top 10 Wettest Years

#Water
Year
SiteENSO StateIntensitySeason
Total
Percent
Normal
11998004A - Casitas DamStrong El Niño+2.359.55255.5%
22005004A - Casitas DamWeak El Niño+0.754.66234.5%
31983004A - Casitas DamStrong El Niño+2.151.13219.3%
41995004A - Casitas DamModerate El Niño+1.049.84213.8%
51978004A - Casitas DamWeak El Niño+0.849.05210.4%
61941004 - Casitas Ranch on Coyote CreekN/AN/A48.02206.0%
71969004A - Casitas DamModerate El Niño+1.046.57199.8%
81958004A - Casitas DamStrong El Niño+1.741.26177.0%
91993004A - Casitas DamNeutral+0.341.20176.7%
101952004 - Casitas Ranch on Coyote CreekWeak El Niño+0.540.51173.8%

Strongest La Ninas

#Water
Year
IntensitySiteSeason
Total
Percent
Normal
11974-1.9004A - Casitas Dam19.8985.3%
21989-1.8004A - Casitas Dam11.7350.3%
31976-1.6004A - Casitas Dam17.9076.8%
42000-1.6004A - Casitas Dam24.29104.2%

Top 10 Driest Years

#Water
Year
SiteENSO StateIntensitySeason
Total
Percent
Normal
12014004A - Casitas DamNeutral-0.58.0134.4%
22007004A - Casitas DamModerate El Niño+1.08.6036.9%
31961004A - Casitas DamNeutral0.08.7737.6%
42002004A - Casitas DamNeutral-0.29.2839.8%
51990004A - Casitas DamNeutral+0.19.4540.5%
62015004A - Casitas DamWeak El Niño+0.59.8042.0%
72018004A - Casitas DamWeak La Nina-1.09.9442.6%
81959004A - Casitas DamWeak El Niño+0.610.2243.8%
92013004A - Casitas DamNeutral-0.410.7246.0%
101987004A - Casitas DamModerate El Niño+1.210.8846.7%