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Monthly climate in Simi Valley, California, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Simi Valley features a warm-summer Mediterranean climate (Csb).Temperatures typically range between 12 °C (55 °F) and 24 °C (75 °F) through the year, but rarely can drop to 1 °C (34 °F) or can rise to as high as 43 °C (110 °F).The average annual precipitation amounts to about 377 mm (14.8 inches) and receives 30 rainy days on the 1 mm (0.04 inches) threshold annually.Simi Valley enjoys an average of 3518 hours of sunshine throughout the year, and daylight varies from 9 hours 54 minutes to 14 hours 22 minutes per day.

Monthly average temperatures in Simi Valley, California, United States §

The warmest months in Simi Valley are July, August and September, with daily mean temperatures ranging from 22 to 24 °C (73 - 75 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 12 to 13 °C (55 - 55 °F) throughout the day. On average each year, Simi Valley experiences 129 days above 25 °C (77.0 °F) and 0 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Simi Valley, California, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 31°C
(88°F)		 29°C
(85°F)		 29°C
(85°F)		 35°C
(95°F)		 33°C
(92°F)		 37°C
(99°F)		 42°C
(108°F)		 39°C
(102°F)		 43°C
(110°F)		 38°C
(101°F)		 32°C
(90°F)		 28°C
(82°F)
Mean maximum 25°C
(78°F)		 25°C
(77°F)		 27°C
(81°F)		 31°C
(89°F)		 30°C
(86°F)		 32°C
(90°F)		 36°C
(97°F)		 35°C
(95°F)		 37°C
(99°F)		 34°C
(94°F)		 31°C
(89°F)		 25°C
(78°F)
Average high 18°C
(65°F)		 19°C
(66°F)		 19°C
(67°F)		 22°C
(72°F)		 23°C
(73°F)		 26°C
(79°F)		 29°C
(84°F)		 30°C
(86°F)		 29°C
(84°F)		 26°C
(80°F)		 23°C
(74°F)		 18°C
(65°F)
Daily mean 13°C
(55°F)		 13°C
(55°F)		 14°C
(57°F)		 17°C
(62°F)		 17°C
(64°F)		 20°C
(69°F)		 23°C
(74°F)		 24°C
(75°F)		 22°C
(73°F)		 20°C
(68°F)		 16°C
(62°F)		 12°C
(55°F)
Average low 8°C
(46°F)		 8°C
(46°F)		 9°C
(48°F)		 11°C
(53°F)		 13°C
(56°F)		 16°C
(61°F)		 19°C
(66°F)		 19°C
(67°F)		 17°C
(64°F)		 14°C
(58°F)		 11°C
(52°F)		 8°C
(46°F)
Mean minimum 3°C
(37°F)		 3°C
(37°F)		 3°C
(39°F)		 8°C
(46°F)		 9°C
(49°F)		 12°C
(54°F)		 16°C
(61°F)		 16°C
(62°F)		 13°C
(55°F)		 9°C
(48°F)		 7°C
(44°F)		 3°C
(39°F)
Minimum 2°C
(35°F)		 1°C
(35°F)		 3°C
(37°F)		 7°C
(44°F)		 8°C
(46°F)		 11°C
(52°F)		 13°C
(56°F)		 16°C
(61°F)		 11°C
(52°F)		 7°C
(45°F)		 4°C
(39°F)		 1°C
(34°F)

Compare climate in Simi Valley with other places

Compare temperature, precipitation, sunshine, UV index in Simi Valley, California, United States with other places around the world.

Monthly average precipitation in Simi Valley, California, United States §

Simi Valley usually has the most precipitation in January, March and December, with an average of 6 rainy days and 81 mm (3.2 inches) of precipitation per month.The driest months in Simi Valley are June, July and August. On average, 1 mm (0.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Simi Valley, California, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 79 (3.1) 63 (2.5) 80 (3.2) 20 (0.8) 15 (0.6) 2 (0.1) 1 (0.0) 1 (0.0) 2 (0.1) 10 (0.4) 19 (0.7) 86 (3.4)
Average precipitation days (≥ 1 mm) 5 5 8 3 2 0 0 0 0 1 1 5

Monthly sunshine hours in Simi Valley, California, United States §

The sunniest months in Simi Valley are June, July and August, when the sun shines an average of 11 hours 57 minutes a day.Least sunny months in Simi Valley: January, February and December receive an average of 6 hours 55 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Simi Valley, California, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 184 225 272 313 350 362 380 358 310 288 252 220
Mean daily daylight hours 10h 9m 10h 57m 11h 59m 13h 3m 13h 56m 14h 22m 14h 8m 13h 21m 12h 20m 11h 16m 10h 21m 9h 54m

Solar UV radiation in Simi Valley, California, United States §

Simi Valley experiences the highest level of ultraviolet (UV) radiation in May, July and August, when the maximum UV index can reach values of 11 - 12, which corresponds to the Extreme category of sun exposure.January, November and December are in the Moderate exposure category. In these months, the maximum values of the UV index do not exceed 5. For more detailed information, check out our hourly Simi Valley UV Index data.

Average daily maximum UV levels by month for Simi Valley, California, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 4 6 8 10 11 11 12 11 10 7 5 4