| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 14.2° | 3.6° | — | — | 75 |
| February | 16.9° | 4.3° | — | — | 84 |
| March | 19.6° | 6° | — | — | 93 |
| April | 23.1° | 7.6° | — | — | 94 |
| May | 28° | 10.8° | — | — | 90 |
| June | 33.1° | 14.2° | — | — | 70 |
| July | 36.8° | 16.9° | — | — | 55 |
| August | 35.7° | 16.2° | — | — | 59 |
| September | 32.7° | 13.5° | — | — | 71 |
| October | 26.8° | 9.2° | — | — | 94 |
| November | 18.9° | 5° | — | — | 90 |
| December | 14.1° | 3.1° | — | — | 75 |
January in Rocklin averages a daily high of 14.2°C with nights around 3.6°C. Comfortable conditions for being outdoors all day.
February in Rocklin averages a daily high of 16.9°C with nights around 4.3°C. Comfortable conditions for being outdoors all day.
March in Rocklin averages a daily high of 19.6°C with nights around 6°C. Comfortable conditions for being outdoors all day.
April in Rocklin averages a daily high of 23.1°C with nights around 7.6°C. Comfortable conditions for being outdoors all day.
May in Rocklin averages a daily high of 28°C with nights around 10.8°C. Comfortable conditions for being outdoors all day.
June in Rocklin averages a daily high of 33.1°C with nights around 14.2°C. Generally workable, with some weather to plan around.
July in Rocklin averages a daily high of 36.8°C with nights around 16.9°C. Generally workable, with some weather to plan around.
August in Rocklin averages a daily high of 35.7°C with nights around 16.2°C. Generally workable, with some weather to plan around.
September in Rocklin averages a daily high of 32.7°C with nights around 13.5°C. Generally workable, with some weather to plan around.
October in Rocklin averages a daily high of 26.8°C with nights around 9.2°C. Comfortable conditions for being outdoors all day.
November in Rocklin averages a daily high of 18.9°C with nights around 5°C. Comfortable conditions for being outdoors all day.
December in Rocklin averages a daily high of 14.1°C with nights around 3.1°C. Comfortable conditions for being outdoors all day.
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. Rocklin peaks at 94.
Based on 30 years of records, March–May scores highest for comfort in Rocklin, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 36.8°C.
January is the wettest, averaging —mm of rain across roughly — wet days.
December is the coolest month, with average daily highs around 14.1°C.