Climate

Sunnyvale weather by month

Average highs, lows, rain and snow for every month, from 30 years of weather records.

Average temperatures

Best time to visit: June, July, August, when highs are mild and rain is lightest.

Month	High	Low	Rain	Wet days
January	59°F	42°F	2.5 in	11
February	62°F	45°F	2.9 in	11
March	65°F	47°F	2.0 in	10
April	68°F	49°F	1.0 in	6
May	72°F	53°F	0.40 in	3
June	76°F	56°F	0.10 in	1
July	77°F	59°F	0.00 in	0
August	77°F	59°F	0.00 in	0
September	78°F	57°F	0.10 in	1
October	74°F	53°F	0.60 in	4
November	66°F	46°F	1.4 in	9
December	59°F	42°F	2.5 in	11

NOAA U.S. Climate Normals 1991–2020, Moffett Federal Airfield, Ca Us (2.5 mi away, 39 ft). Wet days: days with at least 0.01 in of precipitation.

What is the hottest month in Sunnyvale?

September, with an average high of 78°F and low of 57°F.

What is the coldest month in Sunnyvale?

December, with an average low of 42°F and high of 59°F.

When does it rain most in Sunnyvale?

February is the wettest month, averaging 2.9 in of precipitation; the year totals about 13.5 inches.

What is the best time to visit Sunnyvale?

For mild weather (highs between 65°F and 85°F) with the least rain, June, July, August.

Where do these numbers come from?

NOAA’s 1991–2020 U.S. Climate Normals for the Moffett Federal Airfield weather station, 2.5 miles from downtown: 30-year averages, not a forecast.