| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 12° | 6.2° | — | — | 68 |
| February | 13.1° | 6.3° | — | — | 72 |
| March | 15.4° | 6.7° | — | — | 79 |
| April | 17.6° | 7.3° | — | — | 86 |
| May | 20.7° | 9.4° | — | — | 94 |
| June | 24.7° | 12.1° | — | — | 94 |
| July | 28.2° | 14.9° | — | — | 89 |
| August | 28.2° | 15° | — | — | 89 |
| September | 27.1° | 14.9° | — | — | 94 |
| October | 22.2° | 12.6° | — | — | 94 |
| November | 15.4° | 8.7° | — | — | 79 |
| December | 11.5° | 6.1° | — | — | 67 |
January in San Ramon averages a daily high of 12°C with nights around 6.2°C. Generally workable, with some weather to plan around.
February in San Ramon averages a daily high of 13.1°C with nights around 6.3°C. Generally workable, with some weather to plan around.
March in San Ramon averages a daily high of 15.4°C with nights around 6.7°C. Comfortable conditions for being outdoors all day.
April in San Ramon averages a daily high of 17.6°C with nights around 7.3°C. Comfortable conditions for being outdoors all day.
May in San Ramon averages a daily high of 20.7°C with nights around 9.4°C. Comfortable conditions for being outdoors all day.
June in San Ramon averages a daily high of 24.7°C with nights around 12.1°C. Comfortable conditions for being outdoors all day.
July in San Ramon averages a daily high of 28.2°C with nights around 14.9°C. Comfortable conditions for being outdoors all day.
August in San Ramon averages a daily high of 28.2°C with nights around 15°C. Comfortable conditions for being outdoors all day.
September in San Ramon averages a daily high of 27.1°C with nights around 14.9°C. Comfortable conditions for being outdoors all day.
October in San Ramon averages a daily high of 22.2°C with nights around 12.6°C. Comfortable conditions for being outdoors all day.
November in San Ramon averages a daily high of 15.4°C with nights around 8.7°C. Comfortable conditions for being outdoors all day.
December in San Ramon averages a daily high of 11.5°C with nights around 6.1°C. Generally workable, with some weather to plan around.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. San Ramon peaks at 94.
Based on 30 years of records, April–October scores highest for comfort in San Ramon, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28.2°C.
January is the wettest, averaging —mm of rain across roughly — wet days.
December is the coolest month, with average daily highs around 11.5°C.