Simi Valley (CA) Weather & Climate: Best Time to Visit

Depending on the time of the year, temperatures range from very warm to moderate in Simi Valley. Average daytime temperatures reach a very warm 31°C (88°F) in August. In December, the coolest month of the year, temperatures drop to a moderate 18°C (64°F).

At night, temperatures range from around 16°C (61°F) in August to 7°C (45°F) in December.

Check out our detailed temperature page for more information.

Temperature ranges by month

With annual rainfall averaging 280 mm (11 in), Simi Valley maintains relatively low precipitation levels throughout the seasons. Simi Valley can be quite wet during January, receiving approximately 62 mm (2.4 in) of precipitation over 5 rainy days.

In contrast, during the driest month (August), you will experience much drier conditions, with 0.1 mm (0 in) of precipitation spread across 0 rainy days days. For more details, please visit our Simi Valley Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Simi Valley can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 12.1 hours of sunshine daily. In contrast, the city experiences much darker days in November, with only 7.2 hours of sunlight per day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in Simi Valley.

The city experiences its highest humidity in May, reaching 73%. In November, the humidity drops to its lowest level at 50%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year