Boston, MA: average weather by month
NOAA 1991–2020 climate normals at the BOSTON LOGAN INTERNATIONAL AIRPORT station, read through NOAA's Regional Climate Centers' ACIS service. Every column below is the station's own average for that month over that 30-year period — not a forecast. The rainfall figures are NOAA's precipitation normal, so they count rain plus melted snow (and any other frozen precipitation, as water), not rain alone.
59.3°F
44.5°F
43.6 in
All 12 months
| Month | Avg. high | Avg. low | Rainfall | Snowfall |
|---|---|---|---|---|
| January | 36.8°F (3°C) | 23.1°F (-5°C) | 3.39 in (86 mm) | 14.3 in (36.3 cm) |
| February | 39°F (4°C) | 24.6°F (-4°C) | 3.21 in (82 mm) | 14.4 in (36.6 cm) |
| March | 45.5°F (8°C) | 31.1°F (0°C) | 4.17 in (106 mm) | 9.0 in (22.9 cm) |
| April | 56.4°F (14°C) | 40.8°F (5°C) | 3.63 in (92 mm) | 1.6 in (4.1 cm) |
| May | 66.5°F (19°C) | 50.3°F (10°C) | 3.25 in (83 mm) | 0.0 in (0.0 cm) |
| June | 76.2°F (25°C) | 59.7°F (15°C) | 3.89 in (99 mm) | 0.0 in (0.0 cm) |
| July | 82.1°F (28°C) | 66°F (19°C) | 3.27 in (83 mm) | 0.0 in (0.0 cm) |
| August | 80.4°F (27°C) | 65.1°F (18°C) | 3.23 in (82 mm) | 0.0 in (0.0 cm) |
| September | 73.1°F (23°C) | 58.2°F (15°C) | 3.56 in (90 mm) | 0.0 in (0.0 cm) |
| October | 62.1°F (17°C) | 47.5°F (9°C) | 4.03 in (102 mm) | 0.2 in (0.5 cm) |
| November | 51.6°F (11°C) | 37.9°F (3°C) | 3.66 in (93 mm) | 0.7 in (1.8 cm) |
| December | 42.2°F (6°C) | 29.2°F (-2°C) | 4.3 in (109 mm) | 9.0 in (22.9 cm) |
Snowfall is the station's own snowfall normal (fresh snow as it falls, in inches), a separate ACIS element from the rainfall column, which already counts that snow once melted.
Reading the twelve months
By these station averages, July runs the warmest (82.1°F average high) and January the coolest (36.8°F average high). December averages the most rain (4.3 in) and February the least (3.21 in).
Months within our comfort range
We set one fixed, objective threshold ourselves — average high between 65°F and 80°F, and average rainfall under 2 in — and check each of the twelve rows against it. This is not a claim that any other month is bad, and not our judgment of which month suits any trip; it is just which rows on the table above clear the stated numbers. See how we set this threshold.
No month at Boston clears both parts of the threshold at once by this station's normals — most months here run either warmer, cooler, or wetter than the range we set.
Compared with nearby cities we cover
| City | Annual avg. high | Annual avg. low | Annual rainfall |
|---|---|---|---|
| Boston | 59.3°F | 44.5°F | 43.6 in |
| New York, NY | 62.6°F | 48.9°F | 49.5 in |
| Philadelphia, PA | 65.2°F | 47.3°F | 44.1 in |
About the station
These normals are read at a single NOAA/NWS station, BOSTON LOGAN INTERNATIONAL AIRPORT (station ID 14739), not averaged across the whole metro area. A different station nearby — higher ground, closer to water, further inland — can read noticeably different numbers, especially for rain. Run this station's ACIS query yourself.
What this page adds
A search for "boston weather by month" mostly returns a day-by-day forecast calendar (useful only for the next two weeks) or a local weather office page built for a different question. This page puts all twelve months of the 1991–2020 average on one screen, in both °F/°C and inches/mm, names the exact station behind the numbers, and sets it next to a few nearby cities so the difference is visible at a glance.
Source: NOAA's current (1991–2020) climate normals, pulled via the Regional Climate Centers' ACIS lookup tool. How we read this data.