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Alameda County Climate

Alameda County, California

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec59.9°AVG °F

Avg Annual Temp

59.9°F

Annual Precip

18.1"

Annual Snowfall

0.0"

Extreme Heat Days

26

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.4"
3.5"
2.7"
1.3"
0.6"
0.2"
0.0"
0.0"
0.1"
0.9"
1.9"
3.6"
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

3,785

Supports most vegetables & fruits

Last spring frost (32°F): 01/07
First fall frost (32°F): 12/22

Seasonal Overview

Comfort ZoneSpring56°62°4.6"Summer66°69°0.2"Fall56°68°2.9"Winter50°53°10.4"20°40°60°80°100°

National Comparison

Warmer than 71% of US counties
Wetter than 12% of US counties
More seasonal variation than 1% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Alameda County

Climate Verdict

Alameda County has a mild, with an average annual temperature of 59.9°F, semi-arid conditions with only 18.1 inches of annual precipitation, occasional hot days — 26.488888888888887 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 50.0°F. summers are pleasantly cool with July averaging 68.3°F. The climate is remarkably stable year-round, with only a 18°F difference between January and July. January 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

Alameda County closely matches the California statewide average temperature of 58.7°F, it is also noticeably drier, receiving 7.7 inches less precipitation than the state average, the county experiences 32.18203607404499 fewer extreme heat days than the state average.

Climate Profile

About Alameda County Weather

Warmer and Milder Than the National Median

Alameda County averages 59.9°F annually, placing it well above the median temperature for the United States. Its classic Mediterranean climate offers consistently warmer conditions than most of the country.

Slightly Warmer Than the California Average

The county's 59.9°F average temperature exceeds California's state average of 58.7°F. While it stays warm, it receives only 18.1 inches of rain, which is lower than the state's 25.8-inch average.

Cooler than Inland Neighbors

Alameda is slightly cooler than neighboring Contra Costa County, which averages 60.4°F. However, it remains significantly warmer and drier than Northern California coastal counties like Del Norte.

Moderate Summers with Rare Winter Frost

July averages 68.3°F, though the county still sees 26 extreme heat days per year. Winters are mild with a 50.9°F average and zero recorded snowfall.

Prepare for Heatwaves and Low Rainfall

Residents should maintain efficient cooling systems for the 26 days of extreme heat. With only 18.1 inches of rain, drought-resistant landscaping is a practical choice for local homes.

Frequently Asked Questions

What is the average temperature in Alameda County?
The average annual temperature in Alameda County, CA is 59.9°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Alameda County get?
Alameda County receives an average of 18.1 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 Alameda County?
Alameda County receives little to no measurable snowfall in a typical year, based on NOAA 30-year climate normals.
How hot does Alameda County get in summer?
The average summer temperature (June-August) in Alameda County is 67.7°F. The county experiences an average of 26 days per year above 90°F.
How cold are winters in Alameda County?
The average winter temperature (December-February) in Alameda County is 50.9°F. January, typically the coldest month, averages 50.0°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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