30-year climate normals

Alameda County Climate and Weather Averages

Hottest month — July

87.7°

average daily high. The coldest month is December, averaging a low of 37.5°F.

Alameda County gets 15.18" of precipitation a year, and 56% of it falls in Dec, Jan, Feb.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	57.4°	37.8°	2.83"
February	61.0°	39.9°	2.92"
March	65.1°	41.8°	2.25"
April	69.3°	44.6°	1.08"
May	75.3°	49.4°	0.56"
June	82.6°	53.5°	0.14"
July	87.7°	56.6°	0.00"
August	87.5°	56.7°	0.09"
September	85.4°	54.9°	0.08"
October	77.9°	49.2°	0.75"
November	65.6°	41.9°	1.68"
December	57.8°	37.5°	2.80"

Rainfall by month

Alameda County has a distinct wet season. 56% of the year's precipitation arrives in Dec, Jan, Feb.

January 2.83"

February 2.92"

March 2.25"

April 1.08"

May 0.56"

June 0.14"

July 0.00"

August 0.09"

September 0.08"

October 0.75"

November 1.68"

December 2.80"

Annual total 15.18"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 847

Heating degree days How much heating the climate demands 2,709

Approximate annual cooling cost At 33.25¢/kWh, California average $282

Approximate annual electric heating cost Lower where heating is gas rather than electric $315

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Alameda County, where electricity is one line of eight.

Common questions

What is the weather like in Alameda County?

Alameda County averages a high of 87.7°F in July and a low of 37.5°F in December. Annual precipitation is 15.18 inches, with essentially no snow.

When is the rainy season in Alameda County?

The wettest stretch is Dec, Jan, Feb, which accounts for 56% of the year's precipitation. That is a pronounced wet season rather than rain spread evenly through the year.

How hot does it get in Alameda County?

The average daily high in July, the hottest month, is 87.7°F. That drives 847 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Alameda County?

Effectively no. Measurable snowfall is rare in Alameda County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station LIVERMORE MUNI AP, CA US (USW00023285), 6.2 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, California residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.