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Monthly climate in Walla Walla, Washington, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Walla Walla features a hot-summer Mediterranean climate (Csa).Temperatures typically range between 1 °C (34 °F) and 23 °C (74 °F) through the year, but rarely can drop to -19 °C (-1 °F) or can rise to as high as 43 °C (110 °F).The average annual precipitation amounts to about 688 mm (27.1 inches) and receives 113 rainy days on the 1 mm (0.04 inches) threshold annually.Walla Walla enjoys an average of 3115 hours of sunshine throughout the year, and daylight varies from 8 hours 41 minutes to 15 hours 41 minutes per day.

Monthly average temperatures in Walla Walla, Washington, United States §

The warmest months in Walla Walla are June, July and August, with daily mean temperatures ranging from 18 to 23 °C (65 - 74 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 1 to 1 °C (34 - 34 °F) throughout the day. On average each year, Walla Walla experiences 72 days above 25 °C (77.0 °F) and 85 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Walla Walla, 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 12°C
(54°F)		 16°C
(61°F)		 18°C
(65°F)		 27°C
(80°F)		 32°C
(90°F)		 43°C
(110°F)		 39°C
(103°F)		 39°C
(102°F)		 36°C
(97°F)		 28°C
(83°F)		 20°C
(68°F)		 18°C
(65°F)
Mean maximum 10°C
(50°F)		 13°C
(56°F)		 17°C
(64°F)		 23°C
(73°F)		 28°C
(83°F)		 32°C
(90°F)		 37°C
(99°F)		 37°C
(98°F)		 33°C
(91°F)		 23°C
(74°F)		 17°C
(63°F)		 12°C
(55°F)
Average high 4°C
(40°F)		 5°C
(41°F)		 10°C
(50°F)		 14°C
(58°F)		 20°C
(67°F)		 24°C
(76°F)		 30°C
(87°F)		 29°C
(85°F)		 23°C
(74°F)		 15°C
(59°F)		 9°C
(48°F)		 4°C
(39°F)
Daily mean 1°C
(34°F)		 1°C
(34°F)		 5°C
(41°F)		 9°C
(48°F)		 14°C
(57°F)		 18°C
(65°F)		 23°C
(74°F)		 22°C
(72°F)		 17°C
(62°F)		 9°C
(49°F)		 5°C
(41°F)		 1°C
(34°F)
Average low -1°C
(30°F)		 -3°C
(28°F)		 1°C
(34°F)		 3°C
(38°F)		 7°C
(46°F)		 11°C
(53°F)		 15°C
(58°F)		 15°C
(58°F)		 10°C
(51°F)		 4°C
(40°F)		 1°C
(35°F)		 -2°C
(29°F)
Mean minimum -10°C
(14°F)		 -14°C
(8°F)		 -6°C
(21°F)		 -3°C
(26°F)		 1°C
(34°F)		 5°C
(41°F)		 9°C
(48°F)		 8°C
(46°F)		 4°C
(39°F)		 -4°C
(25°F)		 -6°C
(22°F)		 -11°C
(12°F)
Minimum -19°C
(-1°F)		 -17°C
(2°F)		 -12°C
(11°F)		 -7°C
(20°F)		 -1°C
(30°F)		 4°C
(39°F)		 7°C
(45°F)		 6°C
(42°F)		 1°C
(35°F)		 -11°C
(13°F)		 -9°C
(17°F)		 -14°C
(6°F)

Compare climate in Walla Walla with other places

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

Monthly average precipitation in Walla Walla, Washington, United States §

Walla Walla usually has the most precipitation in February, November and December, with an average of 15 rainy days and 100 mm (4.0 inches) of precipitation per month.The driest months in Walla Walla are July, August and September. On average, 12 mm (0.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Walla Walla, 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) 77 (3.0) 125 (4.9) 75 (3.0) 62 (2.4) 48 (1.9) 27 (1.1) 2 (0.1) 8 (0.3) 25 (1.0) 62 (2.4) 84 (3.3) 93 (3.7)
Average precipitation days (≥ 1 mm) 13 18 13 11 9 6 0 1 4 10 13 15

Monthly sunshine hours in Walla Walla, Washington, United States §

The sunniest months in Walla Walla are June, July and August, when the sun shines an average of 12 hours 18 minutes a day.Least sunny months in Walla Walla: January, February and December receive an average of 4 hours 26 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Walla Walla, 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 111 151 241 284 342 365 411 355 291 242 176 141
Mean daily daylight hours 9h 5m 10h 21m 11h 57m 13h 35m 14h 59m 15h 41m 15h 17m 14h 2m 12h 28m 10h 51m 9h 25m 8h 41m

Solar UV radiation in Walla Walla, Washington, United States §

Walla Walla experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure.January, November 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 Walla Walla UV Index data.

Average daily maximum UV levels by month for Walla Walla, 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 4 6 7 9 10 10 9 7 5 3 2