Portland, ME climate
Portland has chilly, snowy winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 79°, a January night drops to 16°, and about 69 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Portland feels like
Winter
Spring
Summer
Fall
Portland weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 16° | 3.4" | 18.6" | 11 | 23 | 14° – 31° |
| February | 35° | 17° | 3.5" | 16.6" | 10 | 21 | 14° – 32° |
| March | 42° | 26° | 4.2" | 13.6" | 11 | 16 | 27° – 41° |
| April | 53° | 35° | 4.4" | 2.8" | 11 | 2 | 41° – 49° |
| May | 63° | 45° | 3.8" | 0 | 13 | 0 | 49° – 59° |
| June | 73° | 55° | 4.4" | 0 | 12 | 0 | 61° – 67° |
| July | 79° | 61° | 3.5" | 0 | 11 | 0 | 65° – 73° |
| August | 78° | 60° | 3.5" | 0 | 9 | 0 | 66° – 72° |
| September | 70° | 52° | 3.9" | 0 | 9 | 0 | 57° – 66° |
| October | 58° | 42° | 5.0" | 0.2" | 11 | 0 | 46° – 57° |
| November | 48° | 32° | 4.4" | 2.3" | 11 | 2 | 35° – 44° |
| December | 38° | 23° | 4.6" | 14.6" | 12 | 11 | 24° – 38° |
| Year | 56° | 38° | 48.5" | 68.7" | 131 | 74 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Portland
Portland gets 49 inches of rain and melted snow a year. October is the wettest month and January the driest. Rain or snow falls on about 131 days a year. Snow covers the ground about 74 days of the year.
About 170 frost-free days a year
In half of years the last 32° night comes by April 26 and the first one by October 15. That leaves about 170 frost-free days for gardens, shorter than 61% of U.S. towns.
Heating and cooling a home in Portland
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Portland, 94% of that work is heating and 6% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Portland and its neighbors
Portland borders 6 towns with climate data. January nights across them vary by 1.8°. Westbrook has both the coldest January nights (14°) and the hottest July afternoons (80°). Portland’s January low is 16° and its July high 79°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Portland compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Portland averaged 1.9° warmer than the 1900s. The biggest change is in December (+3.6°). The shift is larger than in 91% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Portland’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 14° to 32°. August is the most reliable, staying within 6°.
Common questions about Portland’s climate
What is the coldest month in Portland?
January, with a typical high of 32° and a low of 16°.
What is the hottest month in Portland?
July, with a typical high of 79° and a low of 61°. About 5 days a year reach 90°.
How much snow does Portland get?
About 69 inches in a normal winter, most of it in January.
When is the first frost in Portland?
In half of years the first 32° night comes by October 15, and the last spring frost by April 26.
What is the rainiest month in Portland?
October, with 5.0 inches of rain and melted snow. The year totals 49 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Portland itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Portland Intl Jetport, ME (6 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.