Climate
Waltham weather by month
Average highs, lows, rain and snow for every month, from 30 years of weather records.
Average temperatures
- Jan
- Feb
- Mar
- Apr
- May
- Jun
- Jul
- Aug
- Sep
- Oct
- Nov
- Dec
Best time to visit: May, August, September, when highs are mild and rain is lightest.
Month by month
| Month | High | Low | Rain | Wet days |
|---|---|---|---|---|
| January | 37°F | 18°F | 2.9 in | 11 |
| February | 39°F | 19°F | 2.7 in | 10 |
| March | 48°F | 27°F | 3.9 in | 10 |
| April | 60°F | 37°F | 3.8 in | 13 |
| May | 70°F | 47°F | 3.4 in | 13 |
| June | 79°F | 56°F | 3.7 in | 14 |
| July | 85°F | 62°F | 3.5 in | 12 |
| August | 84°F | 60°F | 3.5 in | 12 |
| September | 76°F | 52°F | 3.5 in | 12 |
| October | 64°F | 41°F | 4.2 in | 13 |
| November | 52°F | 32°F | 3.7 in | 11 |
| December | 42°F | 24°F | 3.8 in | 11 |
NOAA U.S. Climate Normals 1991–2020, Bedford Hanscom Fld, Ma Us (6.1 mi away, 133 ft). Wet days: days with at least 0.01 in of precipitation.
Questions
What is the hottest month in Waltham?
July, with an average high of 85°F and low of 62°F.
What is the coldest month in Waltham?
January, with an average low of 18°F and high of 37°F.
When does it rain most in Waltham?
October is the wettest month, averaging 4.2 in of precipitation; the year totals about 42.6 inches.
What is the best time to visit Waltham?
For mild weather (highs between 65°F and 85°F) with the least rain, May, August, September.
Where do these numbers come from?
NOAA’s 1991–2020 U.S. Climate Normals for the Bedford Hanscom Fld weather station, 6.1 miles from downtown: 30-year averages, not a forecast.