| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 3.1° | -4.5° | 89mm | 12 | 12 |
| February | 4.3° | -3.8° | 79.8mm | 10.5 | 20 |
| March | 8° | -0.2° | 101.6mm | 11.1 | 36 |
| April | 13.7° | 5° | 90.9mm | 11.6 | 57 |
| May | 19.3° | 10.3° | 86.4mm | 11.9 | 74 |
| June | 24.6° | 15.6° | 100.8mm | 11.1 | 78 |
| July | 28° | 19.2° | 95.1mm | 10 | 76 |
| August | 27.1° | 18.7° | 80.5mm | 9.3 | 81 |
| September | 23.1° | 14.9° | 87.1mm | 8.8 | 82 |
| October | 17.1° | 9° | 103.8mm | 10.2 | 70 |
| November | 11.1° | 3.4° | 86.1mm | 9.9 | 52 |
| December | 6° | -1.2° | 105mm | 11.8 | 27 |
January in Boston averages a daily high of 3.1°C with nights around -4.5°C. Expect roughly 12 wet days totalling 89mm. A hard month to visit for comfort alone.
February in Boston averages a daily high of 4.3°C with nights around -3.8°C. Expect roughly 10.5 wet days totalling 79.8mm. A hard month to visit for comfort alone.
March in Boston averages a daily high of 8°C with nights around -0.2°C. Expect roughly 11.1 wet days totalling 101.6mm. Demanding conditions — pack for it and plan indoor options.
April in Boston averages a daily high of 13.7°C with nights around 5°C. Expect roughly 11.6 wet days totalling 90.9mm. Generally workable, with some weather to plan around.
May in Boston averages a daily high of 19.3°C with nights around 10.3°C. Expect roughly 11.9 wet days totalling 86.4mm. Generally workable, with some weather to plan around.
June in Boston averages a daily high of 24.6°C with nights around 15.6°C. Expect roughly 11.1 wet days totalling 100.8mm. Comfortable conditions for being outdoors all day.
July in Boston averages a daily high of 28°C with nights around 19.2°C. Expect roughly 10 wet days totalling 95.1mm. Comfortable conditions for being outdoors all day.
August in Boston averages a daily high of 27.1°C with nights around 18.7°C. Expect roughly 9.3 wet days totalling 80.5mm. Comfortable conditions for being outdoors all day.
September in Boston averages a daily high of 23.1°C with nights around 14.9°C. Expect roughly 8.8 wet days totalling 87.1mm. Comfortable conditions for being outdoors all day.
October in Boston averages a daily high of 17.1°C with nights around 9°C. Expect roughly 10.2 wet days totalling 103.8mm. Generally workable, with some weather to plan around.
November in Boston averages a daily high of 11.1°C with nights around 3.4°C. Expect roughly 9.9 wet days totalling 86.1mm. Demanding conditions — pack for it and plan indoor options.
December in Boston averages a daily high of 6°C with nights around -1.2°C. Expect roughly 11.8 wet days totalling 105mm. A hard month to visit for comfort alone.
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. Boston peaks at 82.
Based on 30 years of records, May–September scores highest for comfort in Boston, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28°C.
December is the wettest, averaging 105mm of rain across roughly 11.8 wet days.
January is the coolest month, with average daily highs around 3.1°C.