Sunol, CA climate
Sunol has mild winters and warm summers, with very little rain. A typical July afternoon reaches 86°, a January night drops to 40°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Sunol feels like
Winter
Spring
Summer
Fall
Sunol 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 | 58° | 40° | 3.7" | 0 | 10 | 0 | 45° – 53° |
| February | 61° | 42° | 3.6" | 0 | 10 | 0 | 47° – 56° |
| March | 65° | 44° | 3.2" | 0 | 9 | 0 | 49° – 60° |
| April | 69° | 46° | 1.6" | 0 | 6 | 0 | 53° – 61° |
| May | 75° | 50° | 0.7" | 0 | 4 | 0 | 58° – 68° |
| June | 81° | 54° | 0.1" | 0 | 1 | 0 | 64° – 70° |
| July | 86° | 57° | 0.0" | 0 | 0 | 0 | 68° – 75° |
| August | 86° | 57° | 0.0" | 0 | 0 | 0 | 68° – 76° |
| September | 84° | 56° | 0.1" | 0 | 1 | 0 | 66° – 74° |
| October | 76° | 51° | 1.0" | 0 | 3 | 0 | 60° – 70° |
| November | 65° | 44° | 2.1" | 0 | 7 | 0 | 48° – 58° |
| December | 57° | 40° | 3.8" | 0 | 10 | 0 | 45° – 54° |
| Year | 72° | 48° | 19.9" | 0.0" | 59 | 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 Sunol
Sunol gets 20 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 59 days a year.
About 292 frost-free days a year
In half of years the last 32° night comes by February 15 and the first one by December 2. That leaves about 292 frost-free days for gardens, longer than 94% of U.S. towns.
Heating and cooling a home in Sunol
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Sunol, 74% of that work is heating and 26% is cooling.
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.
Sunol and its neighbors
Sunol borders 3 towns with climate data. January nights across them vary by 2.4°. Pleasanton has both the coldest January nights (39°) and the hottest July afternoons (88°). Sunol’s January low is 40° and its July high 86°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Sunol 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 Sunol averaged 1.7° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is larger than in 78% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Sunol’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. May swings the most: between 1991 and 2020 its average temperature ranged from 58° to 68°. June is the most reliable, staying within 6°.
Common questions about Sunol’s climate
What is the coldest month in Sunol?
January, with a typical high of 58° and a low of 40°.
What is the hottest month in Sunol?
July, with a typical high of 86° and a low of 57°. About 57 days a year reach 90°.
How much snow does Sunol get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Sunol?
In half of years the first 32° night comes by December 2, and the last spring frost by February 15.
What is the rainiest month in Sunol?
December, with 3.8 inches of rain and melted snow. The year totals 20 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Sunol itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Livermore, CA (8 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.