Vacaville, CA climate
Vacaville has mild winters and warm summers, with very little rain. A typical July afternoon reaches 92°, a January night drops to 39°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Vacaville feels like
Winter
Spring
Summer
Fall
Vacaville 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 | 57° | 39° | 4.8" | 0 | 10 | 0 | 44° – 53° |
| February | 62° | 42° | 4.6" | 0 | 10 | 0 | 47° – 57° |
| March | 67° | 44° | 3.2" | 0 | 9 | 0 | 49° – 62° |
| April | 72° | 47° | 1.3" | 0 | 5 | 0 | 55° – 64° |
| May | 79° | 52° | 0.8" | 0 | 3 | 0 | 58° – 73° |
| June | 87° | 56° | 0.2" | 0 | 1 | 0 | 67° – 74° |
| July | 92° | 58° | 0.0" | 0 | 0 | 0 | 71° – 79° |
| August | 91° | 58° | 0.0" | 0 | 0 | 0 | 71° – 78° |
| September | 88° | 56° | 0.1" | 0 | 1 | 0 | 68° – 75° |
| October | 79° | 51° | 0.9" | 0 | 3 | 0 | 62° – 70° |
| November | 66° | 43° | 2.3" | 0 | 7 | 0 | 48° – 59° |
| December | 57° | 39° | 4.8" | 0 | 10 | 0 | 44° – 53° |
| Year | 75° | 49° | 22.9" | 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 Vacaville
Vacaville gets 23 inches of rain and melted snow a year. January is the wettest month and July the driest. Rain or snow falls on about 59 days a year.
About 283 frost-free days a year
In half of years the last 32° night comes by February 18 and the first one by November 28. That leaves about 283 frost-free days for gardens, longer than 94% of U.S. towns.
Heating and cooling a home in Vacaville
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Vacaville, 64% of that work is heating and 36% 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.
Vacaville and its neighbors
Vacaville borders 3 towns with climate data. January nights across them vary by 0.7°. Hartley has both the coldest January nights (39°) and the hottest July afternoons (93°). Vacaville’s January low is 39° and its July high 92°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Vacaville 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 Vacaville averaged 1.6° warmer than the 1900s. The biggest change is in January (+2.1°). The shift is larger than in 76% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Vacaville’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 73°. September is the most reliable, staying within 7°.
Common questions about Vacaville’s climate
What is the coldest month in Vacaville?
December, with a typical high of 57° and a low of 39°.
What is the hottest month in Vacaville?
July, with a typical high of 92° and a low of 58°. About 88 days a year reach 90°.
How much snow does Vacaville get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Vacaville?
In half of years the first 32° night comes by November 28, and the last spring frost by February 18.
What is the rainiest month in Vacaville?
January, with 4.8 inches of rain and melted snow. The year totals 23 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Vacaville itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Fairfield, CA (8 mi, snow) and Vacaville Nut Tree Airport, CA (1 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.