| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 14.2° | 5.8° | 220.4mm | 11.9 | 58 |
| February | 16.8° | 6.2° | 205.7mm | 10.4 | 69 |
| March | 18.7° | 6.8° | 150.2mm | 10.8 | 74 |
| April | 20.9° | 7.9° | 65mm | 6 | 88 |
| May | 23.8° | 9.7° | 34mm | 3.4 | 93 |
| June | 27° | 11.3° | 6mm | 0.9 | 98 |
| July | 28.9° | 11.9° | 0.1mm | 0.2 | 92 |
| August | 28.6° | 12.2° | 1.1mm | 0.2 | 93 |
| September | 28° | 11.7° | 3.4mm | 1.1 | 94 |
| October | 24.7° | 10° | 61.6mm | 3.5 | 93 |
| November | 18° | 7.5° | 118.7mm | 7.6 | 78 |
| December | 14.1° | 5.7° | 268mm | 11.9 | 57 |
January in San Rafael averages a daily high of 14.2°C with nights around 5.8°C. Expect roughly 11.9 wet days totalling 220.4mm. Generally workable, with some weather to plan around.
February in San Rafael averages a daily high of 16.8°C with nights around 6.2°C. Expect roughly 10.4 wet days totalling 205.7mm. Generally workable, with some weather to plan around.
March in San Rafael averages a daily high of 18.7°C with nights around 6.8°C. Expect roughly 10.8 wet days totalling 150.2mm. Generally workable, with some weather to plan around.
April in San Rafael averages a daily high of 20.9°C with nights around 7.9°C. Expect roughly 6 wet days totalling 65mm. Comfortable conditions for being outdoors all day.
May in San Rafael averages a daily high of 23.8°C with nights around 9.7°C. Expect roughly 3.4 wet days totalling 34mm. Comfortable conditions for being outdoors all day.
June in San Rafael averages a daily high of 27°C with nights around 11.3°C. Rain is rare — about 0.9 wet days and 6mm across the month. Comfortable conditions for being outdoors all day.
July in San Rafael averages a daily high of 28.9°C with nights around 11.9°C. Rain is rare — about 0.2 wet days and 0.1mm across the month. Comfortable conditions for being outdoors all day.
August in San Rafael averages a daily high of 28.6°C with nights around 12.2°C. Rain is rare — about 0.2 wet days and 1.1mm across the month. Comfortable conditions for being outdoors all day.
September in San Rafael averages a daily high of 28°C with nights around 11.7°C. Rain is rare — about 1.1 wet days and 3.4mm across the month. Comfortable conditions for being outdoors all day.
October in San Rafael averages a daily high of 24.7°C with nights around 10°C. Expect roughly 3.5 wet days totalling 61.6mm. Comfortable conditions for being outdoors all day.
November in San Rafael averages a daily high of 18°C with nights around 7.5°C. Expect roughly 7.6 wet days totalling 118.7mm. Comfortable conditions for being outdoors all day.
December in San Rafael averages a daily high of 14.1°C with nights around 5.7°C. Expect roughly 11.9 wet days totalling 268mm. 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 Rafael peaks at 98.
Based on 30 years of records, May–October scores highest for comfort in San Rafael, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28.9°C.
December is the wettest, averaging 268mm of rain across roughly 11.9 wet days.
December is the coolest month, with average daily highs around 14.1°C.