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Climate in Portland, Maine: Monthly Weather Averages

By the AverageClimate Editorial Team · Last updated: October 2026

Portland sits at 45 feet above sea level, and its climate, as recorded at the Portland International Jetport, ME station, runs to a yearly mean of 47.5°F. The warmest month is July, averaging 70.4°F with typical highs of 79.5°F; the coldest is January, averaging 24.0°F with lows around 15.6°F. Across a normal year the city receives 48.1 in of precipitation and 68.7 in of snow. The full month-by-month picture below comes from the official 1991–2020 U.S. Climate Normals — the 30-year averages the National Weather Service itself uses — so it describes the Portland climate you should actually plan around, whether you are timing a visit, weighing a move, or just settling an argument about which month is best.

Portland climate month by month

The table below is the complete 1991–2020 normals profile for Portland: average high, average low and mean temperature, rainfall, and snowfall for every month. Read down the Mean column to feel the year's rhythm — Portland's temperature range runs from 24.0°F in January to 70.4°F in July.

How to read the colors:below freezingcoldcoolmildwarmhot. Bands are colored by each cell's own temperature, so a whole year reads at a glance.

Portland through the seasons

Winter in Portland averages highs of 32.4–38.3°F and lows of 15.6–22.4°F, a seasonal mean of 26.8°F. The three months together bring 11.5 in of precipitation — about 24% of the city's yearly total — with December the wettest of the three at 4.50 in. Snowfall averages 49.8 in over the season, most of it in January (18.6 in). Average temperatures sit below freezing, so this is the heart of the heating season: expect snow-covered ground, icy mornings, and short, cold days as the local norm rather than the exception.

Spring in Portland averages highs of 42.3–64.2°F and lows of 26.0–45.5°F, a seasonal mean of 44.5°F. The three months together bring 12.2 in of precipitation — about 25% of the city's yearly total — with April the wettest of the three at 4.41 in. Snowfall averages 16.4 in over the season, most of it in March (13.6 in). The season is a transition: the average temperature climbs 20.8°F from March to May, and by late spring Portland is firmly into mild territory, with May rainfall of 3.67 in to plan around.

Summer in Portland averages highs of 73.6–79.5°F and lows of 55.0–61.2°F, a seasonal mean of 68.0°F. The three months together bring 11.2 in of precipitation — about 23% of the city's yearly total — with June the wettest of the three at 4.15 in. Summer is the mildest in the country by big-city standards — heat waves happen, but the average afternoon stays in the 70s, and many homes historically get by without air conditioning.

Fall in Portland averages highs of 48.4–71.1°F and lows of 31.7–52.1°F, a seasonal mean of 50.6°F. The three months together bring 13.3 in of precipitation — about 28% of the city's yearly total — with October the wettest of the three at 5.25 in. Snowfall averages 2.5 in over the season, most of it in November (2.3 in). Temperatures ease off through the season — the monthly mean drops 21.6°F from September to November — and fall is when Portland's weather turns cooler and wetter, with the first freezes arriving by November.

Best and worst months to visit Portland

Ranking every month by its normals — mild mean temperatures score best, heavy rain and snow count against — the most comfortable months to visit Portland are:

JuneJulyAugust

June leads the list: average highs of 73.6°F, lows of 55.0°F, and 4.15 in of rain, with snow a non-factor at 0.0 in. The other picks, July and August, offer the same balance in Portland's mild stretch of the year. At the other end, January is usually the month to avoid — deep-winter cold, with a mean temperature of 24.0°F and 3.50 in of precipitation plus 18.6 in of snow.

How Portland compares

Across the 114 cities in our dataset, the typical city averages 57.8°F for the year and 35.7 in of precipitation. Portland runs 10.3°F cooler than that typical city and wetter by 12.5 in a year, ranking #97 of 114 for annual warmth and #26 of 114 for precipitation (wettest first). Its year-round temperature swing — warmest month minus coldest — is 46.4°F, which puts it in the strongly continental, four-real-seasons camp.

Planning notes for Portland

For anyone relocating: average overnight lows drop below freezing in 5 months (January, February, March, November, December), so heating, winter tires, and pipe protection are real seasonal concerns; even the warmest month's average high stays below 80°F, so summer heat is rarely a planning factor; 4 months of the year average between 55°F and 80°F, the band most people find comfortable without heating or cooling. Those four facts, all straight from the normals table above, shape everything from a Portland wardrobe to its utility bills.

Portland climate FAQ

Source: 1991–2020 U.S. Climate Normals, NOAA National Centers for Environmental Information (NCEI) — ncei.noaa.gov. Station: Portland International Jetport, ME (USW00014764), elevation 45 ft. Figures checked October 2026.