Annual mean 11°C · wettest around December · prevailing wind W
Warmest
26.0 °C
Coldest
1.5 °C
Wettest
22%
Windiest
4.9 m/s
Prevailing
W
4.0 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 Portsmouth over the whole year is 11°C. July is the hottest month, with highs of about 26°C; January is the coldest, with lows of about -2°C. Portsmouth has no sharply defined rainy season: the chance of rain on a given day runs from 9% in July, the driest month, to 18% in December, the wettest. Winds in Portsmouth are highest in March, averaging 4.0 m/s (14 km/h), and lightest in July, at 2.7 m/s (10 km/h). The prevailing wind is from the W. The clearest skies in Portsmouth come in November, when the sky is typically 42% covered; May is the cloudiest month, at 55%.
Month by month Portsmouth 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
2°C
-2°C
-3°C
14%
52%
3.6 m/s
0
0
6
February
3°C
-1°C
-2°C
17%
51%
3.5 m/s
1
0
11
March
7°C
2°C
1°C
14%
51%
4.0 m/s
1
0
22
April
11°C
6°C
7°C
17%
53%
3.7 m/s
11
0
49
May
17°C
12°C
14°C
16%
55%
3.3 m/s
44
5
76
June
22°C
17°C
22°C
10%
48%
2.9 m/s
78
27
57
July
26°C
21°C
27°C
9%
47%
2.7 m/s
53
62
20
August
25°C
19°C
26°C
10%
44%
2.7 m/s
60
55
27
September
21°C
16°C
21°C
12%
49%
2.9 m/s
74
23
60
October
16°C
11°C
14°C
13%
49%
3.2 m/s
48
4
76
November
10°C
5°C
6°C
13%
42%
3.4 m/s
11
0
42
December
5°C
1°C
-1°C
18%
47%
3.3 m/s
0
0
14
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 Portsmouth weather by season
Year round, Portsmouth has days of about 2°C at their warmest in January, its coolest month, and 26°C in July, its warmest; the coolest hours of the day run from -2°C to 21°C through the year, and the average temperature over the year is 11°C around the clock. Rain is most likely around December and least likely around July. 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.
Portsmouth weather in winterDecember to February
High 3°CLow -1°CRain 16%
Winter in Portsmouth has typical daily highs of about 3°C and lows of about -1°C, with a 16% chance of rain on a given day.
Portsmouth weather in springMarch to May
High 11°CLow 6°CRain 16%
Spring in Portsmouth has typical daily highs of about 11°C and lows of about 6°C, with a 16% chance of rain on a given day.
Portsmouth weather in summerJune to August
High 24°CLow 19°CRain 10%
Summer in Portsmouth has typical daily highs of about 24°C and lows of about 19°C, with a 10% chance of rain on a given day.
Portsmouth weather in autumnSeptember to November
High 16°CLow 10°CRain 12%
Autumn in Portsmouth has typical daily highs of about 16°C and lows of about 10°C, with a 12% chance of rain on a given day.
When is the rainy season in Portsmouth?
Portsmouth has no sharply defined rainy season: the chance of rain on a given day runs from 9% in July, the driest month, to 18% in December, the wettest.
What time of year is Portsmouth windiest?
Winds in Portsmouth are highest in March, averaging 4.0 m/s (14 km/h), and lightest in July, at 2.7 m/s (10 km/h). The prevailing wind is from the W.
What is the average temperature in Portsmouth year round?
The average temperature in Portsmouth over the whole year is 11°C. July is the hottest month, with highs of about 26°C; January is the coldest, with lows of about -2°C.