San Ramon, CA climate
San Ramon 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 decade13° warmer than normal today. The forecast high is 93°, and a typical Oct 1 in San Ramon peaks around 80°.Live forecast: National Weather Service · Normal: NOAA 1991–2020
What a year in San Ramon feels like
Winter
Spring
Summer
Fall
San Ramon 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° | 40° | 4.2" | 0 | 10 | 0 | 45° – 54° |
| February | 60° | 42° | 3.8" | 0 | 10 | 0 | 45° – 56° |
| March | 65° | 44° | 3.1" | 0 | 9 | 0 | 48° – 61° |
| April | 69° | 46° | 1.4" | 0 | 6 | 0 | 53° – 62° |
| May | 75° | 50° | 0.7" | 0 | 4 | 0 | 56° – 71° |
| June | 82° | 54° | 0.1" | 0 | 1 | 0 | 64° – 72° |
| July | 86° | 58° | 0.0" | 0 | 0 | 0 | 68° – 76° |
| August | 86° | 58° | 0.0" | 0 | 0 | 0 | 69° – 76° |
| September | 84° | 56° | 0.1" | 0 | 1 | 0 | 66° – 74° |
| October | 76° | 51° | 1.0" | 0 | 3 | 0 | 60° – 71° |
| November | 64° | 44° | 2.0" | 0 | 7 | 0 | 47° – 59° |
| December | 56° | 39° | 4.1" | 0 | 10 | 0 | 44° – 52° |
| Year | 72° | 48° | 20.3" | 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 San Ramon
San Ramon gets 20 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 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 San Ramon
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In San Ramon, 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.
San Ramon and its neighbors
San Ramon borders 3 towns with climate data. January nights across them vary by 1.5°. Dublin has both the coldest January nights (39°) and the hottest July afternoons (87°). San Ramon’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 San Ramon 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 Ramon averaged 1.6° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is larger than in 77% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at San Ramon’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 56° to 71°. August is the most reliable, staying within 8°.
Common questions about San Ramon’s climate
What is the coldest month in San Ramon?
December, with a typical high of 56° and a low of 39°.
What is the hottest month in San Ramon?
July, with a typical high of 86° and a low of 58°. About 57 days a year reach 90°.
How much snow does San Ramon get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in San Ramon?
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 San Ramon?
January, with 4.2 inches of rain and melted snow. The year totals 20 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for San Ramon 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.