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Monthly climate in Castle Rock, Washington, United States

Last updated: March 2, 2024

Under the Köppen–Geiger climate classification Castle Rock 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 -9 °C (16 °F) or can rise to as high as 44 °C (112 °F). The average annual precipitation amounts to about 1390 mm (54.7 inches) and receives 152 rainy days on the 1 mm (0.04 inches) threshold annually. Castle Rock enjoys an average of 2496 hours of sunshine throughout the year, and daylight varies from 8 hours 40 minutes to 15 hours 42 minutes per day.

Monthly average temperatures in Castle Rock, Washington, United States §

The warmest months in Castle Rock 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, Castle Rock experiences 41 days above 25 °C (77.0 °F) and 41 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Castle Rock, 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)		 15°C
(60°F)		 24°C
(75°F)		 29°C
(85°F)		 30°C
(86°F)		 44°C
(112°F)		 36°C
(96°F)		 38°C
(100°F)		 34°C
(93°F)		 24°C
(76°F)		 17°C
(63°F)		 14°C
(57°F)
Mean maximum 13°C
(55°F)		 13°C
(55°F)		 19°C
(66°F)		 24°C
(76°F)		 28°C
(82°F)		 33°C
(91°F)		 32°C
(90°F)		 35°C
(96°F)		 31°C
(88°F)		 21°C
(70°F)		 16°C
(62°F)		 13°C
(55°F)
Average high 8°C
(47°F)		 8°C
(46°F)		 12°C
(53°F)		 15°C
(59°F)		 19°C
(66°F)		 21°C
(71°F)		 25°C
(77°F)		 26°C
(79°F)		 22°C
(72°F)		 15°C
(60°F)		 11°C
(51°F)		 7°C
(46°F)
Daily mean 5°C
(41°F)		 4°C
(40°F)		 7°C
(45°F)		 10°C
(50°F)		 13°C
(56°F)		 16°C
(61°F)		 18°C
(65°F)		 19°C
(66°F)		 16°C
(61°F)		 10°C
(51°F)		 7°C
(45°F)		 4°C
(40°F)
Average low 2°C
(37°F)		 1°C
(34°F)		 3°C
(38°F)		 5°C
(42°F)		 8°C
(47°F)		 11°C
(51°F)		 12°C
(54°F)		 13°C
(55°F)		 11°C
(52°F)		 6°C
(43°F)		 4°C
(39°F)		 2°C
(36°F)
Mean minimum -5°C
(24°F)		 -5°C
(23°F)		 -2°C
(29°F)		 0°C
(33°F)		 3°C
(38°F)		 6°C
(44°F)		 9°C
(49°F)		 8°C
(48°F)		 6°C
(43°F)		 -1°C
(31°F)		 -3°C
(27°F)		 -5°C
(24°F)
Minimum -9°C
(16°F)		 -8°C
(17°F)		 -3°C
(26°F)		 -1°C
(30°F)		 3°C
(37°F)		 5°C
(42°F)		 8°C
(46°F)		 8°C
(46°F)		 5°C
(42°F)		 -4°C
(25°F)		 -4°C
(25°F)		 -7°C
(19°F)

Compare climate in Castle Rock with other places

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

Monthly average precipitation in Castle Rock, Washington, United States §

Castle Rock usually has the most precipitation in January, November and December, with an average of 18 rainy days and 190 mm (7.5 inches) of precipitation per month. The driest months in Castle Rock are June, July and August. On average, 26 mm (1.0 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Castle Rock, 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) 190 (7.5) 175 (6.9) 150 (5.9) 125 (4.9) 74 (2.9) 59 (2.3) 10 (0.4) 10 (0.4) 84 (3.3) 132 (5.2) 179 (7.0) 202 (8.0)
Average precipitation days (≥ 1 mm) 17 19 18 16 11 8 2 2 9 13 18 19

Monthly sunshine hours in Castle Rock, Washington, United States §

The sunniest months in Castle Rock are June, July and August, when the sun shines an average of 10 hours 31 minutes a day. Least sunny months in Castle Rock: January, February and December receive an average of 3 hours 11 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Castle Rock, 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 80 116 190 215 275 303 346 318 247 189 119 93
Mean daily daylight hours 9h 4m 10h 21m 11h 57m 13h 35m 14h 59m 15h 42m 15h 18m 14h 3m 12h 28m 10h 50m 9h 24m 8h 40m

Solar UV radiation in Castle Rock, Washington, United States §

Castle Rock experiences the highest level of ultraviolet (UV) radiation in May, June and July, when the maximum UV index can reach values of 9 - 10, 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 Castle Rock UV Index data.

Average daily maximum UV levels by month for Castle Rock, 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 10 9 8 7 5 3 2

Detailed Monthly Weather Insights for Castle Rock, Washington, United States

Discover in-depth weather details for every month in Castle Rock. Click through the links below for comprehensive overviews of temperature trends, precipitation levels, sunshine hours, and solar UV radiation specifics. Whether planning a visit or simply curious about Castle Rock's climate nuances, these monthly breakdowns provide the information you need for an informed understanding of what to expect throughout the year.

Each link leads to a detailed account of the typical weather conditions for that month, providing both locals and tourists with vital information to plan their daily activities, wardrobe, and travel itineraries accordingly.