Climate averages 1991–2020
San Ramon weather
in January.
A cool, moderately wet month: the 11th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cool month in San Ramon: daytime highs average 13.8°C and nights cool to about 5.3°C. By daytime temperature it is the 11th warmest of the 12 months.
Expect about 89 mm of rain on roughly 9 days, which makes January a moderately wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 52 min on an average January day.
The nearest other city in this atlas is Hayward (15 km away). In January its highs average 14.0°C, about as warm as San Ramon, with 89 mm of rain.
Among the 498 cities listed in the United States, San Ramon ranks joint 177th of 498 for the warmest January highs and joint 345th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; San Ramon is 4.4°C warmer than that mean.
From January to February, average highs rise by 1.3°C to 15.1°C, and monthly rainfall rises from 89 mm to 94 mm.
The annual picture
January in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Ramon climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January, selected | 13.8°C5.3°C | 5.3°C | 89 | 8.9 | 9.910 h |
| February | 15.1°C6.1°C | 6.1°C | 94 | 9.0 | 10.811 h |
| March | 17.0°C7.3°C | 7.3°C | 70 | 8.4 | 11.912 h |
| April | 19.3°C8.5°C | 8.5°C | 33 | 4.8 | 13.113 h |
| May | 22.5°C10.8°C | 10.8°C | 17 | 3.0 | 14.214 h |
| June | 26.1°C12.9°C | 12.9°C | 3.4 | 0.9 | 14.715 h |
| July | 28.1°C14.4°C | 14.4°C | 0.7 | 0.2 | 14.515 h |
| August | 28.1°C14.7°C | 14.7°C | 1.4 | 0.2 | 13.614 h |
| September | 27.4°C14.1°C | 14.1°C | 1.7 | 0.4 | 12.512 h |
| October | 23.6°C12.0°C | 12.0°C | 21 | 2.9 | 11.311 h |
| November | 17.5°C8.4°C | 8.4°C | 42 | 5.5 | 10.210 h |
| December | 13.6°C5.6°C | 5.6°C | 81 | 8.7 | 9.610 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
January in nearby cities
- Hayward in JanuaryUnited States · 15 kmHigh 14.0°C · Low 5.8°C · 89 mm rain
- Pleasanton in JanuaryUnited States · 16 kmHigh 14.1°C · Low 5.5°C · 86 mm rain
- Union City in JanuaryUnited States · 21 kmHigh 14.3°C · Low 5.9°C · 91 mm rain
- Livermore in JanuaryUnited States · 21 kmHigh 13.9°C · Low 5.3°C · 86 mm rain
- Concord (California), United States in JanuaryUnited States · 23 kmHigh 13.9°C · Low 5.6°C · 93 mm rain
- Fremont in JanuaryUnited States · 26 kmHigh 14.4°C · Low 6.0°C · 91 mm rain
- Oakland in JanuaryUnited States · 26 kmHigh 14.0°C · Low 5.7°C · 93 mm rain
- Berkeley in JanuaryUnited States · 28 kmHigh 13.7°C · Low 5.4°C · 93 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Ramon) is explained once on the San Ramon year overview and on the Sources, method and limits page.
Hayward lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.