weatherbycounty

King County Climate

JanFebMarAprMayJunJulAugSepOctNovDec51.3°AVG °F

Avg Annual Temp

51.3°F

Annual Precip

64.2"

Annual Snowfall

24.7"

Extreme Heat Days

3

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
8.7"
6.0"
6.9"
5.5"
3.9"
3.2"
1.3"
1.5"
3.0"
6.4"
9.5"
8.2"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

9a

Minimum winter temperature range for plant survival

Growing Degree Days

1,925

Favors cool-season crops

Last spring frost (32°F): 04/03
First fall frost (32°F): 11/10

Seasonal Overview

Comfort ZoneSpring44°55°16.4"Summer60°65°6.0"Fall44°60°19.0"Winter39°41°22.9"20°40°60°80°100°

National Comparison

Warmer than 36% of US counties
Wetter than 98% of US counties
More seasonal variation than 3% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: King County

Climate Verdict

King County has a mild, with an average annual temperature of 51.3°F, very wet conditions receiving 64.2 inches of precipitation annually, rare extreme heat with only 3.4499999999999997 days above 90°F annually, moderate snowfall of 24.7 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are mild, with January temperatures averaging 40.1°F. summers are pleasantly cool with July averaging 65.0°F. The climate is remarkably stable year-round, with only a 25°F difference between January and July. December is typically the coldest month and August the warmest.

Outdoor & Gardening Guidance

Growing season and gardening data is currently limited for King County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.

Regional Context

King County closely matches the Washington statewide average temperature of 49.9°F, it is also noticeably wetter, receiving 25.7 inches more precipitation than the state average.

Climate Profile

About King County Weather

A Mild Marine Climate

King County maintains an average annual temperature of 51.3°F, falling slightly below the national median. The region's temperate marine climate avoids the harsh temperature extremes found in much of the central United States.

Warmer Than the State Average

At 51.3°F, the county is warmer than the Washington state average of 49.9°F. Its 64.2 inches of annual precipitation also far exceeds the statewide average of 38.5 inches.

Drier Than Its Western Neighbors

King County receives 64.2 inches of rain, which is significantly less than the 83.3 inches seen in neighboring Mason County. However, it remains wetter than Kitsap County across the sound, which averages 56.9 inches.

Cool Summers and Damp Winters

The county experiences only 3 extreme heat days per year, with July temperatures averaging a mild 65.0°F. Winter brings 24.7 inches of snowfall and average lows near 40.1°F in January.

Prepare for Persistent Rain

High-quality waterproof gear is essential to handle the 64.2 inches of annual rainfall. While air conditioning is less critical given the few extreme heat days, residents should prepare for occasional winter snow accumulation.

Frequently Asked Questions

What is the average temperature in King County?
The average annual temperature in King County, WA is 51.3°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does King County get?
King County receives an average of 64.2 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in King County?
Yes, King County receives an average of 24.7 inches of snowfall per year according to NOAA climate normals.
How hot does King County get in summer?
The average summer temperature (June-August) in King County is 63.4°F. The county experiences an average of 3 days per year above 90°F.
How cold are winters in King County?
The average winter temperature (December-February) in King County is 40.3°F. January, typically the coldest month, averages 40.1°F.

Track your own weather in King County

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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.

Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor
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