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Monthly climate in Grass Valley, California, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Grass Valley features a hot-summer Mediterranean climate (Csa).Temperatures typically range between 7 °C (44 °F) and 26 °C (79 °F) through the year, but rarely can drop to -7 °C (19 °F) or can rise to as high as 41 °C (106 °F).The average annual precipitation amounts to about 1509 mm (59.4 inches) and receives 78 rainy days on the 1 mm (0.04 inches) threshold annually.Grass Valley enjoys an average of 3387 hours of sunshine throughout the year, and daylight varies from 9 hours 26 minutes to 14 hours 52 minutes per day.

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

The warmest months in Grass Valley are June, July and August, with daily mean temperatures ranging from 22 to 26 °C (72 - 79 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 7 to 8 °C (44 - 46 °F) throughout the day. On average each year, Grass Valley experiences 118 days above 25 °C (77.0 °F) and 21 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Grass 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 21°C
(71°F)		 25°C
(77°F)		 27°C
(81°F)		 30°C
(86°F)		 34°C
(93°F)		 40°C
(104°F)		 41°C
(105°F)		 39°C
(103°F)		 41°C
(106°F)		 34°C
(94°F)		 27°C
(81°F)		 22°C
(72°F)
Mean maximum 19°C
(66°F)		 21°C
(71°F)		 24°C
(75°F)		 27°C
(82°F)		 32°C
(89°F)		 36°C
(97°F)		 38°C
(101°F)		 38°C
(100°F)		 37°C
(99°F)		 30°C
(86°F)		 24°C
(76°F)		 19°C
(66°F)
Average high 12°C
(54°F)		 14°C
(57°F)		 15°C
(59°F)		 19°C
(66°F)		 23°C
(74°F)		 29°C
(84°F)		 33°C
(92°F)		 33°C
(91°F)		 29°C
(84°F)		 23°C
(74°F)		 17°C
(63°F)		 12°C
(54°F)
Daily mean 7°C
(45°F)		 8°C
(46°F)		 9°C
(48°F)		 13°C
(55°F)		 17°C
(62°F)		 22°C
(72°F)		 26°C
(79°F)		 25°C
(77°F)		 21°C
(70°F)		 15°C
(60°F)		 10°C
(51°F)		 7°C
(44°F)
Average low 3°C
(38°F)		 3°C
(37°F)		 4°C
(39°F)		 7°C
(44°F)		 10°C
(50°F)		 14°C
(58°F)		 17°C
(63°F)		 17°C
(63°F)		 14°C
(57°F)		 8°C
(48°F)		 5°C
(42°F)		 3°C
(37°F)
Mean minimum -3°C
(27°F)		 -5°C
(24°F)		 -3°C
(27°F)		 -0°C
(32°F)		 4°C
(39°F)		 8°C
(46°F)		 13°C
(56°F)		 12°C
(55°F)		 8°C
(47°F)		 2°C
(37°F)		 -1°C
(31°F)		 -2°C
(28°F)
Minimum -5°C
(24°F)		 -7°C
(19°F)		 -6°C
(21°F)		 -3°C
(26°F)		 1°C
(34°F)		 5°C
(41°F)		 11°C
(53°F)		 11°C
(52°F)		 5°C
(41°F)		 1°C
(34°F)		 -2°C
(28°F)		 -3°C
(28°F)

Compare climate in Grass Valley with other places

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

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

Grass Valley usually has the most precipitation in January, February and March, with an average of 12 rainy days and 272 mm (10.7 inches) of precipitation per month.The driest months in Grass Valley are June, July and August. On average, 5 mm (0.2 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Grass 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) 269 (10.6) 279 (11.0) 267 (10.5) 129 (5.1) 76 (3.0) 13 (0.5) 1 (0.0) 2 (0.1) 23 (0.9) 78 (3.1) 157 (6.2) 215 (8.4)
Average precipitation days (≥ 1 mm) 12 10 15 9 7 2 0 0 2 3 7 11

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

The sunniest months in Grass Valley are June, July and August, when the sun shines an average of 12 hours 26 minutes a day.Least sunny months in Grass Valley: January, February and December receive an average of 5 hours 47 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Grass 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 141 200 248 295 358 385 396 361 314 282 215 186
Mean daily daylight hours 9h 45m 10h 43m 11h 58m 13h 15m 14h 20m 14h 52m 14h 34m 13h 37m 12h 23m 11h 6m 9h 59m 9h 26m

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

Grass Valley experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 10 - 11, which corresponds to the Very High / 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 4. For more detailed information, check out our hourly Grass Valley UV Index data.

Average daily maximum UV levels by month for Grass 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) 3 5 7 8 10 11 11 10 9 6 4 3