San Joaquin, CA climate
San Joaquin has mild winters and hot summers, with very little rain. A typical July afternoon reaches 97°, a January night drops to 39°.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in San Joaquin feels like
Winter
Spring
Summer
Fall
San Joaquin weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 56° | 39° | 1.7" | 43° – 52° |
| February | 63° | 42° | 1.6" | 47° – 57° |
| March | 69° | 45° | 1.4" | 51° – 64° |
| April | 75° | 48° | 0.6" | 56° – 65° |
| May | 84° | 54° | 0.4" | 62° – 76° |
| June | 92° | 60° | 0.0" | 71° – 80° |
| July | 97° | 65° | 0.0" | 77° – 85° |
| August | 96° | 64° | 0.0" | 76° – 84° |
| September | 91° | 60° | 0.1" | 71° – 78° |
| October | 80° | 51° | 0.4" | 62° – 70° |
| November | 66° | 43° | 0.6" | 47° – 60° |
| December | 56° | 38° | 1.2" | 44° – 51° |
| Year | 77° | 51° | 8.1" |
“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 San Joaquin
San Joaquin gets 8 inches of rain and melted snow a year. January is the wettest month and July the driest.
About 271 frost-free days a year
In half of years the last 32° night comes by February 27 and the first one by November 26. That leaves about 271 frost-free days for gardens, longer than 93% of U.S. towns.
Heating and cooling a home in San Joaquin
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In San Joaquin, 53% of that work is heating and 47% 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.
How San Joaquin 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 San Joaquin averaged 1.6° warmer than the 1900s. The biggest change is in September (+2.3°). The shift is larger than in 78% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at San Joaquin’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 62° to 76°. September is the most reliable, staying within 7°.
Common questions about San Joaquin’s climate
What is the coldest month in San Joaquin?
December, with a typical high of 56° and a low of 38°.
What is the hottest month in San Joaquin?
July, with a typical high of 97° and a low of 65°. About 114 days a year reach 90°.
When is the first frost in San Joaquin?
In half of years the first 32° night comes by November 26, and the last spring frost by February 27.
What is the rainiest month in San Joaquin?
January, with 1.7 inches of rain and melted snow. The year totals 8 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for San Joaquin itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Five Points 5 Ssw, CA (17 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.