Portland, ME Climate & Monthly Averages
The climate of Portland
Seasons are the whole story in Portland. The gap between an average July and an average January is 25°C - warm summers and cold, often snowy winters - which in practice means 78°F (26°C) afternoons at one end of the calendar and 33°F (1°C) at the other.
Climate quick facts
- Hottest month: July - highs near 78°F (26°C)
- Coldest month: January - highs near 33°F (1°C)
- Decade extremes (2015-2024): 97°F (36°C) high · -19°F (-28°C) low
- Wettest month: December (11 rainy days) · Sunniest: July (11.3 h sun/day)
- Climate type: humid continental
- Annual swing: 25°C between the average warmest and coolest month · day to night: 8°C
- Snow: about 24 days a year
- Months with freezing average lows: 4
- Average humidity: 73%
Temperatures through the year
Between the average July and the average January lie 25°C, a wider spread than roughly 83% of the cities we track. Warmth peaks in July: highs of 78°F (26°C), lows of 64°F (18°C). January is the coolest month, with highs of 33°F (1°C) and lows near 19°F (-7°C). Sunshine averages 8.4 hours a day over the year, peaking in July at 11.3 hours.
Rain, sun and snow
Overnight lows average at or below freezing for 4 months, December through March. Snow falls on roughly 24 days a year, mostly November through April. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 97°F (36°C) and the lowest daily minimum -19°F (-28°C).
How Portland compares
- Portland averages 48°F (9°C) across the year - cooler than all but 6% of the 3496 cities we track.
- 29% of the year's precipitation falls in its wettest three months - more evenly spread than all but 9% of the 3496 cities we track.
Ranked against every city in our dataset, each measured on the same ten-year window.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 33° | 19° | 10 | 4.1 in | 5.9 h/day | 68% |
| February | 35° | 18° | 9 | 3.2 in | 6.9 h/day | 69% |
| March | 42° | 26° | 11 | 3.8 in | 8.0 h/day | 67% |
| April | 51° | 36° | 11 | 4.5 in | 8.2 h/day | 70% |
| May | 63° | 47° | 9 | 2.7 in | 10.1 h/day | 72% |
| June | 72° | 57° | 11 | 3.8 in | 11.1 h/day | 76% |
| July | 78° | 64° | 10 | 3.8 in | 11.3 h/day | 77% |
| August | 77° | 63° | 11 | 3.6 in | 10.8 h/day | 78% |
| September | 71° | 57° | 8 | 3.4 in | 9.4 h/day | 78% |
| October | 60° | 47° | 9 | 4.5 in | 7.1 h/day | 77% |
| November | 47° | 35° | 9 | 3.8 in | 6.5 h/day | 71% |
| December | 38° | 26° | 11 | 5.0 in | 5.7 h/day | 72% |
Portland month by month
Portland weather in January
January brings highs around 33°F (1°C), lows near 19°F (-7°C), about 10 wet days and roughly 6 snowy days - typically the coldest month of the year in Portland.
Portland weather in February
February brings highs around 35°F (2°C), lows near 18°F (-8°C), about 9 wet days and roughly 6 snowy days.
Portland weather in March
March brings highs around 42°F (5°C), lows near 26°F (-3°C), about 11 wet days and roughly 4 snowy days.
Portland weather in April
April brings highs around 51°F (11°C), lows near 36°F (2°C), about 11 wet days and roughly 2 snowy days.
Portland weather in May
May brings highs around 63°F (17°C), lows near 47°F (8°C), about 9 wet days - typically the driest month of the year in Portland.
Portland weather in June
June brings highs around 72°F (22°C), lows near 57°F (14°C), about 11 wet days.
Portland weather in July
July brings highs around 78°F (26°C), lows near 64°F (18°C), about 10 wet days - typically the hottest month and the sunniest month of the year in Portland.
Portland weather in August
August brings highs around 77°F (25°C), lows near 63°F (17°C), about 11 wet days.
Portland weather in September
September brings highs around 71°F (22°C), lows near 57°F (14°C), about 8 wet days.
Portland weather in October
October brings highs around 60°F (15°C), lows near 47°F (8°C), about 9 wet days.
Portland weather in November
November brings highs around 47°F (9°C), lows near 35°F (2°C), about 9 wet days and roughly 1 snowy days.
Portland weather in December
December brings highs around 38°F (3°C), lows near 26°F (-4°C), about 11 wet days and roughly 4 snowy days - typically the wettest month of the year in Portland.
Seasons in Portland
Spring (March through May)
Spring stays firmly cold here - highs near 52°F (11°C), nights near 37°F (3°C), and rain falls on around 31 of the 90 days, plus about 6 snowy days.
Summer (June through August)
Through summer, Portland is mild and warm: 76°F (24°C) by day, 61°F (16°C) after dark, and rain falls on around 32 of the 90 days. Daylight is generous - around 11.1 hours of sun a day.
Fall (September through November)
Through fall, Portland is mild: 59°F (15°C) by day, 46°F (8°C) after dark, and expect showers on roughly 27 days across the season.
Winter (December through February)
Winter brings deep cold here - highs near 36°F (2°C), nights near 21°F (-6°C), and expect showers on roughly 30 days across the season, plus about 16 snowy days. Wind sharpens cold like this considerably; pair the forecast winds with the wind speed converter to judge exposed conditions.
Climate questions, answered
How often does it rain in Portland?
How sunny is Portland?
How humid does Portland get?
What should I wear in Portland?
Best time to visit Portland
Aim for May to October if you get the choice: these are the warmest and brightest weeks of the year, and highs average 70°F (21°C) against roughly 10 wet days a month. For the same question asked the other way round, see where else is warm in May.
Pack for Portland with a heavy insulated coat, hat and gloves for winter and a compact umbrella or rain shell. Even in July, lows of 64°F (18°C) make an extra layer worth the space.
Portland temperature records (2015-2024)
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ.