Waltham, Massachusetts Weather
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Climate of Waltham: monthly averages
Based on 25 years of satellite and reanalysis data (2001-2025), July is usually the hottest month in Waltham, with average daytime highs around 28°C. January is the coolest, when nights typically fall to about -8°C and frost is possible on the coldest nights. That is a wide yearly range of roughly 35°C, so the seasons feel very different from each other.
The area receives about 1210 mm of rain in a typical year. Most of it falls from March to April, June, October and December, and October is the wettest month at roughly 123 mm.
For outdoor plans and travel, May and July to September usually offer the most comfortable weather in Waltham, with mild days and relatively little rain.
| Month | Avg high | Avg low | Rainfall | Humidity |
|---|---|---|---|---|
| Jan | 1° | -8° | 80 mm | 88% |
| Feb | 2° | -7° | 86 mm | 87% |
| Mar | 6° | -3° | 110 mm | 82% |
| Apr | 13° | 2° | 107 mm | 79% |
| May | 19° | 8° | 95 mm | 79% |
| Jun | 24° | 14° | 113 mm | 79% |
| Jul | 28° | 17° | 94 mm | 75% |
| Aug | 27° | 17° | 93 mm | 73% |
| Sep | 24° | 13° | 92 mm | 75% |
| Oct | 16° | 7° | 123 mm | 79% |
| Nov | 10° | 1° | 98 mm | 82% |
| Dec | 4° | -4° | 116 mm | 86% |
Source: NASA POWER (MERRA-2 reanalysis), averaged over the roughly 50 km grid area around Waltham. Values describe typical conditions, not a forecast.
About Waltham weather
Waltham lies in Massachusetts's humid continental, coastal New England climate — about 15 km west of Boston. Expect warm summers (June–August). Winter brings cold winters (December–February) with regular nor'easter snowstorms. This page shows live, auto-refreshing weather for Waltham: current conditions, an hourly breakdown, a 16-day outlook, a date-lookup tool for any past or future date, and real-time air quality, sourced from Open-Meteo. Local timezone: America/New_York.
Frequently asked questions
Waltham is about 15 km west of Boston, in Massachusetts.
Waltham sees cold winters (December–February) with regular nor'easter snowstorms.
The live current conditions, hourly forecast and 16-day outlook above are pulled in real time for Waltham's exact coordinates. No fixed schedule, the page updates whenever you load it.
July is usually the hottest month in Waltham, with average daytime highs of about 28°C and nights around 17°C.
The coldest nights come in January, when the average low is about -8°C and daytime highs reach around 1°C. Frost is possible on clear, calm nights.
Waltham receives about 1210 mm of rain in a typical year. October is the wettest month at roughly 123 mm, and the main rainy period is March to April, June, October and December.
May and July to September usually offer the most comfortable weather in Waltham, with mild daytime temperatures and little rain.
In November Waltham typically sees daytime highs near 10°C and lows near 1°C, with about 98 mm of rain over the month and average humidity around 82%. Check the live forecast above for this week's actual conditions.
Up to 16 days ahead using the extended forecast and date picker above; further-out or historical dates use the same date lookup tool.
The current temperature for Waltham updates automatically at the top of this page — scroll to the hourly strip below to see how it's expected to change over the day.
Waltham's day-to-day weather follows the broader pattern of Massachusetts described above. See the hourly weather forecast or the air quality index for more detail.