Boston Climate by Month – Rainy Season, Temperature Averages
Summary
The climate figures for Boston are averaged from 2016–2025 observations (10 years). Annual rainfall averages about 1,195 mm.
The rainy season runs March–December. The wettest month is October with 121 mm across 10 rain days; the driest is August at just 76.1 mm.
The hottest month is July (average high 28.7°C) and the coolest is January (3°C).
The most comfortable time to visit Boston is August — less rain and milder heat.
Monthly averages · 2016–2025
| Monthly averages | High | Low | Rainfall | Rainy season |
|---|---|---|---|---|
| January | 3.0° | -5.0° | 99 mm | 10 |
| February | 4.9° | -4.7° | 87 mm | 10 |
| March | 8.3° | -1.2° | 110 mm | 11 |
| April | 13.3° | 3.9° | 109 mm | 12 |
| May | 19.3° | 9.8° | 94 mm | 12 |
| June | 25.1° | 15.3° | 79 mm | 11 |
| July | 28.7° | 19.2° | 115 mm | 12 |
| August | 27.6° | 18.4° | 76 mm | 11 |
| September | 23.2° | 14.8° | 108 mm | 10 |
| October | 17.5° | 9.1° | 121 mm | 10 |
| November | 10.6° | 2.1° | 83 mm | 9 |
| December | 5.0° | -2.9° | 116 mm | 10 |