Annual mean 9°C · wettest around April · prevailing wind SW
Warmest
24.9 °C
Coldest
-1.8 °C
Wettest
33%
Windiest
4.4 m/s
Prevailing
SW
3.5 m/s average
When this place is good five ratings · thirty-six ten-day sections · click a cell to read it
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Every reading
bars actual · line feels-like, °Cchance of rain, %wind speed, m/ssky covered, %
The average temperature in South Portland over the whole year is 9°C. July is the hottest month, with highs of about 25°C; January is the coldest, with lows of about -6°C. South Portland has no sharply defined rainy season: the chance of rain on a given day runs from 16% in September, the driest month, to 26% in April, the wettest. Winds in South Portland are highest in March, averaging 3.2 m/s (12 km/h), and lightest in August, at 2.0 m/s (7 km/h). The prevailing wind is from the SW. The clearest skies in South Portland come in July, when the sky is typically 41% covered; May is the cloudiest month, at 51%.
Month by month South Portland climate by month: average temperatures year round · click a month to read it
Month
High
Low
Feels like
Chance of rain
Cloud
Wind
Being outside
Sun
Walking
January
-1°C
-6°C
-7°C
19%
48%
2.9 m/s
0
0
2
February
0°C
-5°C
-6°C
20%
46%
2.9 m/s
0
0
5
March
4°C
-2°C
-2°C
21%
48%
3.2 m/s
0
0
11
April
10°C
4°C
5°C
26%
50%
3.1 m/s
6
0
37
May
16°C
10°C
13°C
24%
51%
2.7 m/s
34
5
69
June
21°C
15°C
20°C
22%
45%
2.4 m/s
69
21
61
July
25°C
19°C
25°C
22%
41%
2.2 m/s
60
51
30
August
24°C
17°C
24°C
21%
41%
2.0 m/s
70
41
39
September
21°C
13°C
20°C
16%
41%
2.0 m/s
72
18
67
October
14°C
8°C
12°C
23%
50%
2.3 m/s
33
2
71
November
7°C
2°C
3°C
19%
43%
2.7 m/s
6
0
26
December
1°C
-3°C
-4°C
24%
46%
2.7 m/s
0
0
6
High and low are the warmest and coolest of four readings a day — midnight, 6am, noon and 6pm — so a true overnight low can sit a degree or two under them. Chance of rain, cloud and wind are the day’s average; feels-like and the three ratings (each out of 100: Good from 55, Ideal from 80) are read at midday.
Seasons, and the year in short South Portland weather by season
Year round, South Portland has days of about -1°C at their warmest in January, its coolest month, and 25°C in July, its warmest; the coolest hours of the day run from -6°C to 19°C through the year, and the average temperature over the year is 9°C around the clock. Rain is most likely around April and least likely around September. Every figure here is a decade of observations blended into one representative year, so it reads as what this date is usually like, not a forecast for one particular day.
South Portland weather in winterDecember to February
High -0°CLow -5°CRain 21%
Winter in South Portland has typical daily highs of about -0°C and lows of about -5°C, with a 21% chance of rain on a given day.
South Portland weather in springMarch to May
High 10°CLow 4°CRain 24%
Spring in South Portland has typical daily highs of about 10°C and lows of about 4°C, with a 24% chance of rain on a given day.
South Portland weather in summerJune to August
High 23°CLow 17°CRain 21%
Summer in South Portland has typical daily highs of about 23°C and lows of about 17°C, with a 21% chance of rain on a given day.
South Portland weather in autumnSeptember to November
High 14°CLow 8°CRain 20%
Autumn in South Portland has typical daily highs of about 14°C and lows of about 8°C, with a 20% chance of rain on a given day.
When is the rainy season in South Portland?
South Portland has no sharply defined rainy season: the chance of rain on a given day runs from 16% in September, the driest month, to 26% in April, the wettest.
What time of year is South Portland windiest?
Winds in South Portland are highest in March, averaging 3.2 m/s (12 km/h), and lightest in August, at 2.0 m/s (7 km/h). The prevailing wind is from the SW.
What is the average temperature in South Portland year round?
The average temperature in South Portland over the whole year is 9°C. July is the hottest month, with highs of about 25°C; January is the coldest, with lows of about -6°C.