Acton, CA climate
Acton has mild winters and hot summers, with very little rain. A typical July afternoon reaches 93°, a January night drops to 37°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Acton feels like
Winter
Spring
Summer
Fall
Acton 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° | 37° | 2.3" | 0 | 5 | 0 | 44° – 54° |
| February | 60° | 38° | 2.6" | 0 | 6 | 0 | 41° – 56° |
| March | 65° | 41° | 1.8" | 0 | 5 | 0 | 46° – 60° |
| April | 70° | 44° | 0.7" | 0 | 2 | 0 | 51° – 62° |
| May | 77° | 50° | 0.2" | 0 | 1 | 0 | 55° – 71° |
| June | 87° | 57° | 0.0" | 0 | 0 | 0 | 65° – 77° |
| July | 93° | 63° | 0.0" | 0 | 0 | 0 | 74° – 83° |
| August | 93° | 63° | 0.0" | 0 | 0 | 0 | 75° – 82° |
| September | 88° | 58° | 0.1" | 0 | 1 | 0 | 68° – 78° |
| October | 77° | 50° | 0.5" | 0 | 2 | 0 | 59° – 69° |
| November | 66° | 41° | 0.6" | 0 | 3 | 0 | 46° – 59° |
| December | 57° | 36° | 1.7" | 0 | 5 | 0 | 41° – 52° |
| Year | 74° | 48° | 10.6" | 0.0" | 32 | 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 Acton
Acton gets 11 inches of rain and melted snow a year. February is the wettest month and August the driest. Rain or snow falls on about 32 days a year.
About 248 frost-free days a year
In half of years the last 32° night comes by March 10 and the first one by November 19. That leaves about 248 frost-free days for gardens, longer than 90% of U.S. towns.
Heating and cooling a home in Acton
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Acton, 55% of that work is heating and 45% 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.
Acton and its neighbors
Acton borders 2 towns with climate data. January nights across them vary by 4.6°. Palmdale has both the coldest January nights (35°) and the hottest July afternoons (96°). Acton’s January low is 37° and its July high 93°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Acton 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 Acton averaged 2.0° warmer than the 1900s. The biggest change is in January (+2.8°). The shift is larger than in 94% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Acton’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 55° to 71°. August is the most reliable, staying within 7°.
Common questions about Acton’s climate
What is the coldest month in Acton?
December, with a typical high of 57° and a low of 36°.
What is the hottest month in Acton?
August, with a typical high of 93° and a low of 63°. About 118 days a year reach 90°.
How much snow does Acton get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Acton?
In half of years the first 32° night comes by November 19, and the last spring frost by March 10.
What is the rainiest month in Acton?
February, with 2.6 inches of rain and melted snow. The year totals 11 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Acton itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Acton Escondido Fc261, CA (5 mi, snow) and Palmdale, CA (8 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.