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Marin County Climate

Marin County, California

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec59.4°AVG °F

Avg Annual Temp

59.4°F

Annual Precip

38.4"

Annual Snowfall

0.0"

Extreme Heat Days

23

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
7.5"
7.5"
5.0"
2.3"
1.2"
0.3"
0.0"
0.1"
0.1"
1.7"
4.1"
8.5"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

10a

Minimum winter temperature range for plant survival

Growing Degree Days

3,615

Supports most vegetables & fruits

Last spring frost (32°F): 01/16
First fall frost (32°F): 12/21

Seasonal Overview

Comfort ZoneSpring55°61°8.5"Summer66°68°0.4"Fall55°68°5.9"Winter49°52°23.5"20°40°60°80°100°

National Comparison

Warmer than 69% of US counties
Wetter than 42% of US counties
More seasonal variation than 1% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Marin County

Climate Verdict

Marin County has a mild, with an average annual temperature of 59.4°F, moderate rainfall of 38.4 inches per year, occasional hot days — 23.45 per year above 90°F, virtually no measurable snowfall. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are mild, with January temperatures averaging 49.5°F. summers are pleasantly cool with July averaging 67.9°F. The climate is remarkably stable year-round, with only a 18°F difference between January and July. December is typically the coldest month and August the warmest.

Outdoor & Gardening Guidance

The moderate temperatures support hiking, cycling, and camping comfortably in spring, summer, and fall.

Regional Context

Marin County closely matches the California statewide average temperature of 58.7°F, it is also noticeably wetter, receiving 12.6 inches more precipitation than the state average, the county experiences 35.22092496293388 fewer extreme heat days than the state average.

Climate Profile

About Marin County Weather

Temperate and mild coastal climate

Marin County averages 59.4°F annually, making it warmer than the national median but famously stable. Its proximity to the Pacific Ocean prevents the extreme temperature swings found in the interior.

Right in the California sweet spot

Marin's 59.4°F average is nearly identical to the California state average of 58.7°F. It represents the classic Northern California coastal profile: mild, foggy, and consistent.

A rain-soaked coastal neighbor

Marin is much wetter than the state average, receiving 38.4 inches of rain compared to the California norm of 25.8 inches. This high precipitation supports its famous redwood forests and green hills.

Few extreme heat days annually

Summers are cool with a July average of 67.9°F and only 23 days of heat over 90°F. Snow is non-existent at 0.0 inches, while winters stay mild with a January average of 49.5°F.

Pack layers and prepare for rain

The 38.4 inches of rain require high-quality waterproof gear and well-maintained drainage systems. With only 23 heat days, many residents rely on coastal breezes rather than heavy air conditioning.

Frequently Asked Questions

What is the average temperature in Marin County?
The average annual temperature in Marin County, CA is 59.4°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Marin County get?
Marin County receives an average of 38.4 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 Marin County?
Marin County receives little to no measurable snowfall in a typical year, based on NOAA 30-year climate normals.
How hot does Marin County get in summer?
The average summer temperature (June-August) in Marin County is 67.3°F. The county experiences an average of 23 days per year above 90°F.
How cold are winters in Marin County?
The average winter temperature (December-February) in Marin County is 50.4°F. January, typically the coldest month, averages 49.5°F.

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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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