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Best time to visit · Maine, United States
For the most comfortable weather in Portland, Maine, aim for September. September tops our comfort score at 87/100, with highs around 65°F (18°C) and 3.8 in (97 mm) of rain. June – August are good shoulder-season months. The toughest months are March and December & January, mainly because of cool days.
Highs run from 34°F to 70°F across the year, and the yearly total is about 53.7 in (1363 mm) of rain and snow.
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high | 34°F1°C | 35°F1°C | 38°F4°C | 46°F8°C | 54°F12°C | 62°F17°C | 69°F21°C | 70°F21°C | 65°F18°C | 56°F13°C | 47°F9°C | 40°F4°C |
| Avg low | 25°F-4°C | 26°F-4°C | 31°F-1°C | 38°F4°C | 47°F8°C | 56°F13°C | 63°F17°C | 64°F18°C | 58°F15°C | 49°F10°C | 40°F5°C | 31°F0°C |
| Rain/snow | 4.1 in103 mm | 4.1 in103 mm | 4.3 in110 mm | 4.8 in121 mm | 4.0 in101 mm | 5.0 in127 mm | 3.8 in96 mm | 3.7 in94 mm | 3.8 in97 mm | 5.7 in145 mm | 4.9 in125 mm | 5.6 in141 mm |
| Humidity | 85% | 83% | 81% | 83% | 87% | 88% | 88% | 86% | 83% | 81% | 81% | 83% |
| Cloud | 65% | 63% | 62% | 62% | 66% | 62% | 55% | 52% | 50% | 59% | 61% | 66% |
| Comfort | 41 | 42 | 41 | 49 | 63 | 75 | 72 | 74 | 87 | 64 | 51 | 36 |
Source: NASA POWER (public domain), 2001–2025 monthly averages on a ~50 km satellite and reanalysis grid, so coasts and valleys can differ from what's shown. The grid cell sits at about 12 m (39 ft), close to Portland, Maine's own ~19 m. Precipitation includes snow as melted water; daylight is calculated from latitude. Check a forecast before you go.
The coldest season, with highs of 34–40°F (1–4°C) and lows down to 25°F (-4°C). About 13.7 in (347 mm) of rain or snow falls across these months, 25% of the year's total. January & February are cold enough for snow. Comfort scores bottom out in December & January; the season averages 40/100.
Temperatures climb through the season, from 38°F highs in March to 54°F by May. About 13.1 in (332 mm) of rain falls across these months, 24% of the year's total. Nights dip below freezing in March. It holds the toughest stretch on our comfort score (March), averaging 51/100.
Peak warmth: highs of 62–70°F (17–21°C). It's the driest season, with only about 12.5 in (317 mm) of rain, 23% of the year's total. Lows bottom out around 56°F (13°C). June – August score well without being the very best (season average 74/100).
Temperatures slide from 65°F highs in September to 47°F by November. It's the wettest season, with about 14.4 in (367 mm) of rain, 27% of the year's total. Lows bottom out around 40°F (5°C). Comfort peaks here: September ranks with the year's best, and the season averages 67/100.
By comfort score: 2 Great, 4 Good, 2 Fair and 4 Tough. Great months: June and September. Tap a month for its own guide.
For the most comfortable weather in Portland, Maine, aim for September. September tops our comfort score at 87/100, with highs around 65°F (18°C) and 3.8 in (97 mm) of rain. June – August are good shoulder-season months. The toughest months are March and December & January, mainly because of cool days.
October is the wettest month, averaging about 5.7 in (145 mm) of rain. August is the driest, with about 3.7 in (94 mm). The yearly total is around 53.7 in (1363 mm).
January is the coldest, with average lows of 25°F (-4°C) and highs of 34°F (1°C). The warmest is August, with average highs of 70°F (21°C).
Not very: summer (June – August) humidity averages 87%, and highs peak around 70°F (21°C), so it rarely feels sticky.
On average, yes: lows fall below 32°F (0°C) in December – March, bottoming out around 25°F (-4°C) in January.
Poll the group on September dates, then plan the days, packing and costs together.
