Boston records about 1112mm of rain across roughly 126 wet days a year, which is a 35% chance on an average day. December is the wettest month at 99mm (9% of the annual total) and February the driest at 84mm. Local rain type: snow mix. Boston gets substantial precipitation year-round — winter brings heavy snow, summer brings thunderstorms. Pack weather-appropriate gear for any season.
Chance of rain on an average day: 35%
Rainfall climatology for Boston. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 1112mm |
| Rain days per year | 126 |
| Odds on an average day | 35% |
| Wettest month | December — 99mm over 11 days |
| Driest month | February — 84mm over 10 days |
| Rain type | snow mix |
| Best dry window | September and early October offer the driest weather during spectacular New England foliage season. |
| Worst rain window | December through February brings heavy snow, while spring (March-April) combines rain, slush, and occasional snow. |
December delivers 18% more rain than February (99mm vs 84mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 9% of the annual total, so rain in Boston is spread through the year — there is no season you can rely on being dry.
Boston rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 11 days in December against 10 in February — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 92mm | 11 | 37% | 2°C |
| February | 84mm | 10 | 33% | 2°C |
| March | 99mm | 11 | 37% | 6°C |
| April | 93mm | 11 | 37% | 12°C |
| May | 84mm | 10 | 33% | 18°C |
| June | 89mm | 10 | 33% | 24°C |
| July | 84mm | 10 | 33% | 28°C |
| August | 86mm | 10 | 33% | 28°C |
| September | 89mm | 10 | 33% | 24°C |
| October | 95mm | 11 | 37% | 18°C |
| November | 92mm | 11 | 37% | 12°C |
| December | 99mm | 11 | 37% | 6°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Boston we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Boston records rain on roughly 126 days a year — about a 35% chance on any given day — totalling around 1112mm.
December, with about 99mm over 11 rain days. That is 9% of the entire year's rainfall in a single month.
February is the driest month at 84mm across roughly 10 days. September and early October offer the driest weather during spectacular New England foliage season.
Boston gets substantial precipitation year-round — winter brings heavy snow, summer brings thunderstorms. Pack weather-appropriate gear for any season.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.