| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 3.8° | -4.4° | 60.8mm | 9.4 | 20 |
| February | 4.9° | -4.2° | 65.9mm | 8.7 | 25 |
| March | 8.9° | -0.3° | 89.3mm | 9.9 | 41 |
| April | 14.8° | 4.7° | 106.6mm | 10.7 | 62 |
| May | 20.1° | 10.2° | 89.3mm | 12.5 | 75 |
| June | 25.1° | 15.5° | 92.9mm | 11.5 | 77 |
| July | 28.7° | 19.5° | 87.1mm | 10.5 | 72 |
| August | 27.9° | 18.8° | 87.7mm | 9.8 | 77 |
| September | 24.4° | 14.7° | 103.2mm | 9.2 | 82 |
| October | 18.2° | 8.6° | 102.2mm | 10.6 | 73 |
| November | 12.4° | 2.7° | 71.2mm | 9 | 58 |
| December | 6.8° | -1.2° | 97.9mm | 11.2 | 31 |
January in New Haven averages a daily high of 3.8°C with nights around -4.4°C. Expect roughly 9.4 wet days totalling 60.8mm. A hard month to visit for comfort alone.
February in New Haven averages a daily high of 4.9°C with nights around -4.2°C. Expect roughly 8.7 wet days totalling 65.9mm. A hard month to visit for comfort alone.
March in New Haven averages a daily high of 8.9°C with nights around -0.3°C. Expect roughly 9.9 wet days totalling 89.3mm. Demanding conditions — pack for it and plan indoor options.
April in New Haven averages a daily high of 14.8°C with nights around 4.7°C. Expect roughly 10.7 wet days totalling 106.6mm. Generally workable, with some weather to plan around.
May in New Haven averages a daily high of 20.1°C with nights around 10.2°C. Expect roughly 12.5 wet days totalling 89.3mm. Comfortable conditions for being outdoors all day.
June in New Haven averages a daily high of 25.1°C with nights around 15.5°C. Expect roughly 11.5 wet days totalling 92.9mm. Comfortable conditions for being outdoors all day.
July in New Haven averages a daily high of 28.7°C with nights around 19.5°C. Expect roughly 10.5 wet days totalling 87.1mm. Generally workable, with some weather to plan around.
August in New Haven averages a daily high of 27.9°C with nights around 18.8°C. Expect roughly 9.8 wet days totalling 87.7mm. Comfortable conditions for being outdoors all day.
September in New Haven averages a daily high of 24.4°C with nights around 14.7°C. Expect roughly 9.2 wet days totalling 103.2mm. Comfortable conditions for being outdoors all day.
October in New Haven averages a daily high of 18.2°C with nights around 8.6°C. Expect roughly 10.6 wet days totalling 102.2mm. Generally workable, with some weather to plan around.
November in New Haven averages a daily high of 12.4°C with nights around 2.7°C. Expect roughly 9 wet days totalling 71.2mm. Generally workable, with some weather to plan around.
December in New Haven averages a daily high of 6.8°C with nights around -1.2°C. Expect roughly 11.2 wet days totalling 97.9mm. 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. New Haven peaks at 82.
Based on 30 years of records, May–June scores highest for comfort in New Haven, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 28.7°C.
April is the wettest, averaging 106.6mm of rain across roughly 10.7 wet days.
January is the coolest month, with average daily highs around 3.8°C.