Annual mean 16°C · wettest around February · prevailing wind NW
Warmest
29.8 °C
Coldest
7.0 °C
Wettest
41%
Windiest
5.0 m/s
Prevailing
NW
4.1 m/s average
When this place is good five ratings · thirty-six ten-day sections · click a cell to read it
never good
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 16°C. July is the hottest month, with highs of about 29°C; January is the coldest, with lows of about 4°C. Portsmouth has no sharply defined rainy season: the chance of rain on a given day runs from 27% in October, the driest month, to 34% in February, the wettest. Winds in Portsmouth are highest in March, averaging 4.1 m/s (15 km/h), and lightest in August, at 2.9 m/s (10 km/h). The prevailing wind is from the NW. The clearest skies in Portsmouth come in July, when the sky is typically 36% covered; May is the cloudiest month, at 50%.
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
7°C
4°C
3°C
31%
44%
3.7 m/s
7
0
31
February
10°C
6°C
7°C
34%
48%
3.6 m/s
17
0
42
March
13°C
8°C
10°C
33%
44%
4.1 m/s
26
2
54
April
18°C
13°C
16°C
31%
41%
4.1 m/s
50
12
64
May
22°C
17°C
22°C
33%
50%
3.7 m/s
61
32
49
June
27°C
22°C
28°C
32%
39%
3.2 m/s
41
57
16
July
29°C
24°C
33°C
32%
36%
3.2 m/s
11
48
3
August
28°C
23°C
31°C
30%
41%
2.9 m/s
21
54
5
September
25°C
21°C
27°C
29%
46%
3.3 m/s
50
51
23
October
21°C
15°C
20°C
27%
42%
3.0 m/s
67
21
63
November
14°C
10°C
12°C
31%
37%
3.2 m/s
31
4
63
December
10°C
6°C
6°C
32%
41%
3.2 m/s
13
0
44
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 7°C at their warmest in January, its coolest month, and 29°C in July, its warmest; the coolest hours of the day run from 4°C to 24°C through the year, and the average temperature over the year is 16°C around the clock. Rain is most likely around February and least likely around October. 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 9°CLow 5°CRain 32%
Winter in Portsmouth has typical daily highs of about 9°C and lows of about 5°C, with a 32% chance of rain on a given day.
Portsmouth weather in springMarch to May
High 18°CLow 13°CRain 32%
Spring in Portsmouth has typical daily highs of about 18°C and lows of about 13°C, with a 32% chance of rain on a given day.
Portsmouth weather in summerJune to August
High 28°CLow 23°CRain 31%
Summer in Portsmouth has typical daily highs of about 28°C and lows of about 23°C, with a 31% chance of rain on a given day.
Portsmouth weather in autumnSeptember to November
High 20°CLow 15°CRain 29%
Autumn in Portsmouth has typical daily highs of about 20°C and lows of about 15°C, with a 29% 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 27% in October, the driest month, to 34% in February, the wettest.
What time of year is Portsmouth windiest?
Winds in Portsmouth are highest in March, averaging 4.1 m/s (15 km/h), and lightest in August, at 2.9 m/s (10 km/h). The prevailing wind is from the NW.
What is the average temperature in Portsmouth year round?
The average temperature in Portsmouth over the whole year is 16°C. July is the hottest month, with highs of about 29°C; January is the coldest, with lows of about 4°C.