Portland (ME) monthly weather averages

Average daytime temperature

The bar chart below shows the average monthly peak daytime temperatures at Portland

Portland average temperature chart (Celsius) Portland average temperature chart (Fahrenheit)
Average monthly temperatures in Portland (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C -0.8 0.6 5.3 11.4 17.3 22.5 25.9 25.1 20.7 14.9 8.4 1.8
°F 30.6 33.1 41.6 52.4 63.1 72.6 78.6 77.2 69.3 58.9 47.1 35.3

Please note: these are the average peak daytime temperatures (usually around mid-afternoon) so do not show daytime / night highs and lows. To see the daily range of temperatures have a look at the temperature max / min chart below.

Average rainfall & rainy days

The graph below shows the average rainfall and number of rainy days per month.

Portland monthly rainfall chart (mm) Portland monthly rainfall chart (inches)
Average monthly rainfall in Portland (mm and inches)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
mm 94 88 99 105 92 85 78 75 81 100 131 117
inches 3.7 3.5 3.9 4.1 3.6 3.3 3.1 3 3.2 3.9 5.1 4.6
Rainy days 11 10 11 12 12 11 10 10 9 10 12 12

Average annual rainfall in Portland: 1117.333mm (439.9 inches)

Average daily sunshine

The bar chart below shows the average daily sunshine hours in Portland

Portland average daily sunshine chart
Average daily sunshine Portland
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Hrs sunshine 5.8 6.6 7 7.6 8.4 9.2 9.7 9.2 8.1 6.8 5.1 5

Day / night temperatures

The graph below shows the daily range of temperatures for each month.

Portland average minimum / maximum temperatures (Celsius) Portland average minimum / maximum temperatures (Fahrenheit)
Maximum and minimum daily temperatures in Portland (degrees centigrade and fahrenheit)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C -11.1 -10.1 -4 1.4 6.5 11.4 14.9 14.2 9.8 4 -0.6 -7.7
Max °C -0.5 0.9 5.6 11.6 17.6 22.8 26.2 25.4 21 15.2 8.6 2.1
Min °F 12 13.8 24.9 34.5 43.6 52.5 58.7 57.6 49.6 39.2 30.9 18.2
Max °F 21.6 23.7 33.4 43.7 53.6 62.8 68.9 67.6 59.7 49.3 39.2 27

Sea temperature

The graph below shows the average sea temperature.

Portland average sea temperature chart (Celsius) Portland average sea temperature chart (Fahrenheit)
Average sea temperature around Portland in degrees centigrade and fahrenheit
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
°C 5 3.5 3.2 4.7 8.4 12.8 16.5 17.5 15.5 12.2 9.3 7
°F 40.9 38.3 37.7 40.5 47.1 55.1 61.8 63.4 59.8 53.9 48.7 44.5

Wind speed

The graph below shows the average wind speed.

Portland average winspeed by month (km/h) Portland average winspeed by month (mph)
Average wind speed in Portland (mph and kmh)
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
km/h 16 16 17 17 15 14 13 13 13 14 15 15
mph 10 10 11 11 9 9 8 8 8 9 9 9

A monthly average windspeed of over 16km/h or 10mph suggests a location is fairly windy.

Relative humidity

The graph below shows the average relative humidity.

Portland relative humidity averages
Average relative humidity in Portland
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
67% 65% 66% 67% 71% 75% 75% 76% 77% 74% 73% 70%