Temperature for September
In San Nicolas Island, CA during September the average high temperature is 73.2°F. The hottest day on record was September 23, 2012 when the temperature hit 100.9°F.
Precipitation for September
In September the average monthly rainfall in San Nicolas Island, CA is 0.23 inches with rain usually falling on between 1 and 2 days. 2012 was the driest September with only 0.00 inches of rain falling, and 1980 was the wettest September with 1.46 inches of rain. The wettest single day in September was 11 September 1976 when 0.43 inches of rain fell.
In September there have been some years when thunderstorms have occurred, although there are other years when there hasn't been a thunderstorm in September.