San Ramon, California climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put San Ramon's center at January lows of 40°F and July highs of 86°F, a yearly mean of 60.1°F and 20.3 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Mount Diablo Junction (8 miles N, 2,170 ft), has January lows of 42°F and July highs of 83°F.
85,924 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 57° 40°
- Feb 60° 42°
- Mar 65° 44°
- Apr 69° 46°
- May 75° 50°
- Jun 82° 54°
- Jul 86° 58°
- Aug 86° 58°
- Sep 84° 56°
- Oct 76° 51°
- Nov 64° 44°
- Dec 56° 39°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at San Ramon's center.
What is each month like in San Ramon?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Mount Diablo Junction high | Mount Diablo Junction low |
|---|---|---|---|---|---|---|
| January | 57°F | 40°F | 48.1°F | 4.15 | 54°F | 42°F |
| February | 60°F | 42°F | 50.8°F | 3.79 | 55°F | 42°F |
| March | 65°F | 44°F | 54.4°F | 3.09 | 58°F | 43°F |
| April | 69°F | 46°F | 57.4°F | 1.42 | 62°F | 44°F |
| May | 75°F | 50°F | 62.5°F | 0.66 | 68°F | 49°F |
| June | 82°F | 54°F | 68.1°F | 0.13 | 76°F | 55°F |
| July | 86°F | 58°F | 72.0°F | 0.00 | 83°F | 62°F |
| August | 86°F | 58°F | 72.0°F | 0.02 | 83°F | 61°F |
| September | 84°F | 56°F | 70.0°F | 0.08 | 80°F | 60°F |
| October | 76°F | 51°F | 63.6°F | 0.95 | 72°F | 54°F |
| November | 64°F | 44°F | 54.3°F | 1.99 | 60°F | 46°F |
| December | 56°F | 39°F | 47.9°F | 4.05 | 53°F | 41°F |
In metric: a yearly mean of 15.6°C, January lows of 4°C, July highs of 30°C and 516 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around San Ramon say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Mount Diablo Junction | 8 mi N | 2,170 ft | 58.4°F | 42°F | 83°F | 26.1 | 1 | March 8 |
| LivermoreLivermore Municipal Airport | 8 mi SE | 393 ft | 59.8°F | 38°F | 88°F | 15.2 | – | February 27 |
| HaywardHayward Air Terminal | 13 mi SW | 43 ft | 59.6°F | 43°F | 75°F | 16.0 | – | January 2 |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in San Ramon?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Mount Diablo Junction (8 miles N, 2,170 ft). It gets 1 inch of snow in a normal year. The last spring frost (32°F) comes after March 8 in half of years and the first autumn frost before December 22. Its record high is 111°F (1972) and its record low 14°F (1989) (kept since 1952).
The USDA's 2023 Plant Hardiness Zone Map puts San Ramon in zone 9b across its 2 ZIP code areas.
Over a year 89% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (5.3 kWh per square metre a day, NASA POWER 2001-2020); July is the sunniest month (97%) and January the cloudiest (74%).
Mount Diablo Junction's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for San Ramon; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00045915; records: ACIS; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across San Ramon, ZIP code by ZIP code?
2 ZIP code areas lie wholly or partly in San Ramon. On NOAA's grid 94582 is the warmest (60.3°F a year) and 94583 the coolest (59.8°F), a spread of 0.5°F. Each row also names the nearest station record and its frost dates.
| ZIP code | Zone | Year | Jan low | Jul high | Precip. | Nearest record | Last frost | First frost |
|---|---|---|---|---|---|---|---|---|
| 94582 | 9b | 60.3°F | 40°F | 87°F | 19.3 | Livermore (7 mi) | February 27 | December 1 |
| 94583 | 9b | 59.8°F | 40°F | 86°F | 21.2 | Mount Diablo Junction (8 mi) | March 8 | December 22 |
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.