What is the hottest month in Millbrae, CA?

September is the warmest month, with a normal high of 75°F at San Francisco INTL AP.

What is the coldest month in Millbrae, CA?

January is the coldest month, with a normal low of 45°F.

What is the wettest month in Millbrae, CA?

December has the most precipitation on average, about 4.14 inches.

Checked Oct 25, 2026

Millbrae, CA Climate

1991 to 2020 normals at San Francisco INTL AP, 2.5 mi from the center of Millbrae, elevation 8 ft.

Average weather by month

Select a month for daily normals and last year's weather

Month	High	Low	Precip.	Snow
January	58°	45°	3.89 in	--
February	61°	46°	3.96 in	--
March	63°	48°	2.73 in	--
April	66°	49°	1.36 in	--
May	68°	52°	0.48 in	--
June	72°	54°	0.14 in	--
July	73°	55°	0.00 in	--
August	73°	56°	0.04 in	--
September	75°	56°	0.07 in	--
October	72°	53°	0.79 in	--
November	64°	49°	2.04 in	--
December	58°	45°	4.14 in	--
Year	67°		19.64 in	--

Frequently asked questions

What is the hottest month in Millbrae, CA?: September is the warmest month, with a normal high of 75°F at San Francisco INTL AP.
What is the coldest month in Millbrae, CA?: January is the coldest month, with a normal low of 45°F.
What is the wettest month in Millbrae, CA?: December has the most precipitation on average, about 4.14 inches.

Today

Millbrae, CA forecast

Data sources

U.S. Climate Normals 1991-2020NOAA National Centers for Environmental Information
U.S. Climate Normals 1991-2020 (daily) and GHCN-Daily via Access Data ServiceNOAA National Centers for Environmental Information

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About this data

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Climate normals are 30-year averages measured at one weather station, which may be miles from the place named here or at a different elevation.

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