Portland, ME Climate & Monthly Averages
Portland has a humid continental climate. July is the hottest month, averaging 78° by day; January is the coldest at 33°.
Winter sets the pace in 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.
July
78° by day 64° at nightJanuary
33° by day 19° at nightThe cold-weather pattern in numbers
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.
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).
More climate facts for Portland
- 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%
From snow season to the warmest stretch 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.
The coldest and warmest values in the dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.
Planning around winter in Portland
The easier weather window
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.
Cold-weather packing
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.
Monthly highs, lows and seasonal change
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 33° | 19° | 10 | 4.1 in | 5.9 h/day | 9.3 h | 32% | 68% |
| February | 35° | 18° | 9 | 3.2 in | 6.9 h/day | 10.4 h | 33% | 69% |
| March | 42° | 26° | 11 | 3.8 in | 8.0 h/day | 11.8 h | 35% | 67% |
| April | 51° | 36° | 11 | 4.5 in | 8.2 h/day | 13.4 h | 38% | 70% |
| May | 63° | 47° | 9 | 2.7 in | 10.1 h/day | 14.7 h | 28% | 72% |
| June | 72° | 57° | 11 | 3.8 in | 11.1 h/day | 15.4 h | 37% | 76% |
| July | 78° | 64° | 10 | 3.8 in | 11.3 h/day | 15.1 h | 33% | 77% |
| August | 77° | 63° | 11 | 3.6 in | 10.8 h/day | 14.0 h | 35% | 78% |
| September | 71° | 57° | 8 | 3.4 in | 9.4 h/day | 12.4 h | 28% | 78% |
| October | 60° | 47° | 9 | 4.5 in | 7.1 h/day | 10.9 h | 30% | 77% |
| November | 47° | 35° | 9 | 3.8 in | 6.5 h/day | 9.6 h | 30% | 71% |
| December | 38° | 26° | 11 | 5.0 in | 5.7 h/day | 8.9 h | 35% | 72% |
The route from winter to summer, month by month
Each card shows the average high and low. The bar places that month between Portland's coldest night and warmest afternoon.
January
- Rain
- 10 days
- Sunshine
- 5.9 h
- Daylight
- 9.3 h
- Snow
- 6 days
February
- Rain
- 9 days
- Sunshine
- 6.9 h
- Daylight
- 10.4 h
- Snow
- 6 days
March
- Rain
- 11 days
- Sunshine
- 8.0 h
- Daylight
- 11.8 h
- Snow
- 4 days
April
- Rain
- 11 days
- Sunshine
- 8.2 h
- Daylight
- 13.4 h
- Snow
- 2 days
May
- Rain
- 9 days
- Sunshine
- 10.1 h
- Daylight
- 14.7 h
June
- Rain
- 11 days
- Sunshine
- 11.1 h
- Daylight
- 15.4 h
July
- Rain
- 10 days
- Sunshine
- 11.3 h
- Daylight
- 15.1 h
August
- Rain
- 11 days
- Sunshine
- 10.8 h
- Daylight
- 14.0 h
September
- Rain
- 8 days
- Sunshine
- 9.4 h
- Daylight
- 12.4 h
October
- Rain
- 9 days
- Sunshine
- 7.1 h
- Daylight
- 10.9 h
November
- Rain
- 9 days
- Sunshine
- 6.5 h
- Daylight
- 9.6 h
- Snow
- 1 day
December
- Rain
- 11 days
- Sunshine
- 5.7 h
- Daylight
- 8.9 h
- Snow
- 4 days
Looking for warmer alternatives? Browse warm places by month, or compare Portland's coolest part of the year: January, February, December.
Where Portland sits among other climates
- 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.
These comparisons use the same ten-year window for every city in the dataset.