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Monthly climate in Chehalis, Washington, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Chehalis features a warm-summer Mediterranean climate (Csb).Temperatures typically range between 4 °C (40 °F) and 19 °C (66 °F) through the year, but rarely can drop to -8 °C (18 °F) or can rise to as high as 43 °C (109 °F).The average annual precipitation amounts to about 1362 mm (53.6 inches) and receives 153 rainy days on the 1 mm (0.04 inches) threshold annually.Chehalis enjoys an average of 2558 hours of sunshine throughout the year, and daylight varies from 8 hours 36 minutes to 15 hours 46 minutes per day.

Monthly average temperatures in Chehalis, Washington, United States §

The warmest months in Chehalis are July, August and September, with daily mean temperatures ranging from 16 to 19 °C (61 - 66 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 4 to 5 °C (40 - 41 °F) throughout the day. On average each year, Chehalis experiences 38 days above 25 °C (77.0 °F) and 40 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Chehalis, Washington, 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 15°C
(59°F)		 14°C
(58°F)		 25°C
(77°F)		 28°C
(83°F)		 30°C
(86°F)		 43°C
(109°F)		 35°C
(95°F)		 37°C
(98°F)		 32°C
(91°F)		 24°C
(76°F)		 17°C
(63°F)		 13°C
(56°F)
Mean maximum 13°C
(55°F)		 12°C
(54°F)		 19°C
(66°F)		 23°C
(74°F)		 27°C
(81°F)		 32°C
(90°F)		 32°C
(91°F)		 35°C
(95°F)		 29°C
(85°F)		 20°C
(69°F)		 16°C
(61°F)		 13°C
(55°F)
Average high 8°C
(47°F)		 8°C
(46°F)		 11°C
(53°F)		 14°C
(58°F)		 18°C
(65°F)		 21°C
(70°F)		 25°C
(77°F)		 25°C
(78°F)		 21°C
(71°F)		 15°C
(59°F)		 10°C
(51°F)		 7°C
(45°F)
Daily mean 5°C
(41°F)		 4°C
(40°F)		 7°C
(45°F)		 10°C
(49°F)		 13°C
(56°F)		 16°C
(60°F)		 18°C
(65°F)		 19°C
(66°F)		 16°C
(61°F)		 10°C
(51°F)		 7°C
(45°F)		 5°C
(40°F)
Average low 3°C
(37°F)		 1°C
(35°F)		 3°C
(38°F)		 5°C
(41°F)		 8°C
(47°F)		 10°C
(51°F)		 12°C
(54°F)		 13°C
(55°F)		 11°C
(52°F)		 6°C
(43°F)		 4°C
(40°F)		 2°C
(36°F)
Mean minimum -4°C
(25°F)		 -5°C
(23°F)		 -2°C
(28°F)		 -0°C
(32°F)		 3°C
(38°F)		 6°C
(43°F)		 9°C
(48°F)		 9°C
(48°F)		 5°C
(42°F)		 -0°C
(32°F)		 -2°C
(28°F)		 -5°C
(24°F)
Minimum -8°C
(18°F)		 -8°C
(19°F)		 -3°C
(27°F)		 -3°C
(28°F)		 2°C
(36°F)		 5°C
(42°F)		 8°C
(47°F)		 7°C
(45°F)		 4°C
(40°F)		 -3°C
(27°F)		 -4°C
(25°F)		 -6°C
(21°F)

Compare climate in Chehalis with other places

Compare temperature, precipitation, sunshine, UV index in Chehalis, Washington, United States with other places around the world.

Monthly average precipitation in Chehalis, Washington, United States §

Chehalis usually has the most precipitation in January, November and December, with an average of 18 rainy days and 189 mm (7.4 inches) of precipitation per month.The driest months in Chehalis are June, July and August. On average, 27 mm (1.1 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Chehalis, Washington, 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) 186 (7.3) 169 (6.7) 137 (5.4) 119 (4.7) 71 (2.8) 54 (2.1) 12 (0.5) 15 (0.6) 88 (3.5) 132 (5.2) 181 (7.1) 198 (7.8)
Average precipitation days (≥ 1 mm) 17 19 17 16 10 8 3 3 10 13 17 20

Monthly sunshine hours in Chehalis, Washington, United States §

The sunniest months in Chehalis are June, July and August, when the sun shines an average of 10 hours 44 minutes a day.Least sunny months in Chehalis: January, November and December receive an average of 3 hours 12 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Chehalis, Washington, 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 81 120 200 223 287 310 352 324 251 193 119 94
Mean daily daylight hours 9h 1m 10h 19m 11h 57m 13h 37m 15h 3m 15h 46m 15h 22m 14h 5m 12h 28m 10h 49m 9h 21m 8h 36m

Solar UV radiation in Chehalis, Washington, United States §

Chehalis experiences the highest level of ultraviolet (UV) radiation in May, June and July, when the maximum UV index can reach values of 9 - 9, which corresponds to the Very High category of sun exposure.January, February and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Chehalis UV Index data.

Average daily maximum UV levels by month for Chehalis, Washington, 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) 2 3 5 6 9 9 9 8 7 5 3 2