Sunnyvale, CA climate
Sunnyvale has warm winters and pleasant summers, with very little rain. A typical July afternoon reaches 80°, a January night drops to 41°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Sunnyvale feels like
Winter
Spring
Summer
Fall
Sunnyvale weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 60° | 41° | 3.2" | 0 | 10 | 0 | 47° – 54° |
| February | 63° | 43° | 3.4" | 0 | 10 | 0 | 49° – 58° |
| March | 66° | 45° | 2.5" | 0 | 8 | 0 | 51° – 61° |
| April | 69° | 47° | 1.2" | 0 | 5 | 0 | 54° – 61° |
| May | 73° | 51° | 0.5" | 0 | 3 | 0 | 58° – 66° |
| June | 78° | 54° | 0.1" | 0 | 1 | 0 | 62° – 68° |
| July | 80° | 56° | 0.0" | 0 | 0 | 0 | 65° – 71° |
| August | 80° | 56° | 0.0" | 0 | 0 | 0 | 65° – 72° |
| September | 79° | 55° | 0.1" | 0 | 1 | 0 | 64° – 71° |
| October | 75° | 51° | 0.7" | 0 | 3 | 0 | 60° – 69° |
| November | 66° | 45° | 1.6" | 0 | 6 | 0 | 49° – 59° |
| December | 59° | 41° | 3.1" | 0 | 10 | 0 | 46° – 55° |
| Year | 71° | 49° | 16.3" | 0.0" | 56 | 0 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Sunnyvale
Sunnyvale gets 16 inches of rain and melted snow a year. February is the wettest month and July the driest. Rain or snow falls on about 56 days a year.
A year-round growing season
Heating and cooling a home in Sunnyvale
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Sunnyvale, 84% of that work is heating and 16% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Sunnyvale and its neighbors
Sunnyvale borders 6 towns with climate data. January nights across them vary by 1.8°. Cupertino has the coldest January nights (39°) and San Jose the hottest July afternoons (86°). Sunnyvale’s January low is 41° and its July high 80°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Sunnyvale compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Sunnyvale averaged 1.8° warmer than the 1900s. The biggest change is in August (+2.2°). The shift is larger than in 87% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Sunnyvale’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 51° to 61°. July is the most reliable, staying within 6°.
Common questions about Sunnyvale’s climate
What is the coldest month in Sunnyvale?
December, with a typical high of 59° and a low of 41°.
What is the hottest month in Sunnyvale?
August, with a typical high of 80° and a low of 56°. About 9 days a year reach 90°.
How much snow does Sunnyvale get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Sunnyvale?
Frost is uncommon. Only 70% of years see a night at 32° or below.
What is the rainiest month in Sunnyvale?
February, with 3.4 inches of rain and melted snow. The year totals 16 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Sunnyvale itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Palo Alto, CA (7 mi, snow) and Moffett Federal Airfield, CA (2 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.