Climateby Month

Portland, ME climate by month

NOAA 1991-2020 normals · 53 ft elevation

Portland has warm summers and cold and snowy winters. Highs peak at 80°F in July and fall to 32°F in January. Wet days are spread through the year, from about 9 to 13 a month. Normal snowfall is about 69 in a year. By our comfort score the best months are June and September.

Warmest month
80°F
July normal high
Coldest month
16°F
January normal low
Wet days a year
131
48.1 in of precipitation
Snow a year
68.7 in
normal snowfall

How warm is Portland?

Normal highs range from 32°F in January to 80°F in July.

0°20°40°60°80° January: normal high 32°F (0°C), low 16°F (-9°C) 32° 16° February: normal high 35°F (2°C), low 17°F (-8°C) March: normal high 42°F (6°C), low 26°F (-3°C) April: normal high 54°F (12°C), low 35°F (2°C) May: normal high 64°F (18°C), low 46°F (8°C) June: normal high 74°F (23°C), low 55°F (13°C) July: normal high 80°F (27°C), low 61°F (16°C) 80° 61° August: normal high 79°F (26°C), low 60°F (16°C) September: normal high 71°F (22°C), low 52°F (11°C) October: normal high 60°F (16°C), low 41°F (5°C) November: normal high 48°F (9°C), low 32°F (0°C) December: normal high 38°F (3°C), low 22°F (-6°C) JFMAMJJASOND

Bars run from the normal low to the normal high for each month.

How rainy is Portland?

May has the most wet days (about 13); the year brings about 48 in of precipitation.

January: 11 wet days February: 10 wet days March: 11 wet days April: 11 wet days May: 13 wet days 13 June: 12 wet days July: 11 wet days August: 9 wet days September: 9 wet days 9 October: 11 wet days November: 11 wet days December: 12 wet days JFMAMJJASOND

Wet day: at least 0.01 in of rain or melted snow, counted from daily records 1991-2020.

How much does it snow?

Normal snowfall is 68.7 in a year, most of it in January.

January: 18.6 in of snow 18.6 February: 16.6 in of snow March: 13.6 in of snow April: 2.8 in of snow May: 0.0 in of snow 0.0 June: 0.0 in of snow July: 0.0 in of snow August: 0.0 in of snow September: 0.0 in of snow October: 0.2 in of snow November: 2.3 in of snow December: 14.6 in of snow JFMAMJJASOND

How humid is Portland?

Muggy days peak in July, at about 7 days.

January: 0 muggy days 0 February: 0 muggy days March: 0 muggy days April: 0 muggy days May: 0 muggy days June: 2 muggy days July: 7 muggy days 7 August: 6 muggy days September: 2 muggy days October: 0 muggy days November: 0 muggy days December: 0 muggy days JFMAMJJASOND

Muggy day: daily mean dew point of 65°F or higher, from hourly observations 1991-2020 at Portland International Jetport Airport, 2.8 mi WSW of the city center.

How much daylight?

Daylight ranges from about 9.0 hours in December to 15.4 hours in June.

January: 9.4 hours of daylight February: 10.5 hours of daylight March: 11.9 hours of daylight April: 13.4 hours of daylight May: 14.7 hours of daylight June: 15.4 hours of daylight 15.4 July: 15.1 hours of daylight August: 13.9 hours of daylight September: 12.5 hours of daylight October: 11.0 hours of daylight November: 9.7 hours of daylight December: 9.0 hours of daylight 9.0 JFMAMJJASOND
See all numbers
Monthly climate normals and day counts for Portland, 1991-2020
MonthHighLowPrecip.Wet daysSnowMuggy daysDaylight
January 32°F16°F 3.5 in11 18.6 in 0 9.4 h
February 35°F17°F 3.5 in10 16.6 in 0 10.5 h
March 42°F26°F 4.1 in11 13.6 in 0 11.9 h
April 54°F35°F 4.4 in11 2.8 in 0 13.4 h
May 64°F46°F 3.7 in13 0.0 in 0 14.7 h
June 74°F55°F 4.2 in12 0.0 in 2 15.4 h
July 80°F61°F 3.4 in11 0.0 in 7 15.1 h
August 79°F60°F 3.6 in9 0.0 in 6 13.9 h
September 71°F52°F 3.8 in9 0.0 in 2 12.5 h
October 60°F41°F 5.3 in11 0.2 in 0 11.0 h
November 48°F32°F 4.3 in11 2.3 in 0 9.7 h
December 38°F22°F 4.5 in12 14.6 in 0 9.0 h

High and low: NOAA 1991-2020 normal daily high and low. Wet days: at least 0.01 in of rain or melted snow. Muggy days: daily mean dew point 65°F or higher.

Best months to visit Portland

By our comfort score, the best months are June and September.

Comfort score by month (0-100) and its parts, in days per month
MonthScoreComfortableNotable rainHot or cold
Jan 240725
Feb 280721
Mar 381714
Apr 53372
May 681270
Jun 741571
Jul 661072
Aug 681251
Sep 711751
Oct 52670
Nov 39176
Dec 270819

Score = 40 × share of comfortable days + 25 × share of days without notable rain + 20 × share of days neither hot (90°F+) nor cold (high 40°F or below) + 15 × daylight. How the score works.

Frost dates in Portland

The last spring frost typically comes around Apr 26, and the first fall frost around Oct 15, leaving 170 frost-free days in a typical year.

Frost and freeze dates for Portland
Typical date1 year in 10
Last spring frost (32°F)Apr 26after May 7
First fall frost (32°F)Oct 15before Oct 2
Last hard freeze (28°F)Apr 14after Apr 25
First hard freeze (28°F)Oct 27before Oct 14
Frost-free season170 daysunder 153 days

"Typical" is the date with a 50% chance of a later spring frost (or earlier fall frost). Planting after the "1 year in 10" spring date gives a 90% chance of no further frost. The Old Farmer's Almanac publishes 30% dates, which fall between our typical and 1-in-10 dates.

Station: Portland Intl Jetport (USW00014764), NOAA 1991-2020 freeze probabilities. Frost dates for every city in Maine.

Hottest and coldest readings, 1991-2020

The highest reading was 100°F (July 22, 2011); the lowest was -18°F (January 27, 1994).

From the temperature station's daily records with NOAA quality flags removed. Not an all-time record.

Near Portland

Similar climates elsewhere

Where the numbers come from

  • Temperature, rain, snowfall, snow depth, frost dates and humidity and wind by hour: Portland Intl Jetport (USW00014764), 2.4 mi WSW of the city center, 45 ft . NOAA normals and daily records, 1991-2020.
  • Daily humidity and wind: Portland International Jetport Airport (726060-14764), 2.8 mi WSW of the city center, 44 ft . Hourly observations, 1991-2020.
  • Not available for this location: cloud cover (no station close enough or similar enough in elevation).

Distances from the city center (USGS). Methodology · Report an error