Climate averages 1991–2020
Portsmouth weather
in May.
A mild, moderately wet month: the 5th warmest and one of the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a mild month in Portsmouth: daytime highs average 16.0°C and nights cool to about 9.0°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 50 mm of rain on roughly 9 days, which makes May a moderately wet month (one of the driest months of the year). Daylight, from sunrise to sunset, lasts about 15 h 29 min on an average May day.
The nearest other city in this atlas is Southampton (25 km away). In May its highs average 15.9°C, about as warm as Portsmouth, with 57 mm of rain.
Among the 143 cities listed in the United Kingdom, Portsmouth ranks joint 28th of 143 for the warmest May highs and joint 15th of 143 for the driest May (rainfall, lowest first). The mean May high of those 143 cities is 15.2°C; Portsmouth is 0.8°C warmer than that mean.
From May to June, average highs rise by 2.7°C to 18.7°C, and monthly rainfall rises from 50 mm to 51 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Portsmouth climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.9°C3.7°C | 3.7°C | 83 | 13.4 | 8.58 h |
| February | 8.1°C3.3°C | 3.3°C | 61 | 10.6 | 10.010 h |
| March | 10.3°C4.4°C | 4.4°C | 50 | 10.0 | 11.812 h |
| April | 12.9°C6.0°C | 6.0°C | 52 | 9.7 | 13.814 h |
| May, selected | 16.0°C9.0°C | 9.0°C | 50 | 9.1 | 15.515 h |
| June | 18.7°C11.8°C | 11.8°C | 51 | 9.4 | 16.416 h |
| July | 20.8°C14.0°C | 14.0°C | 52 | 9.6 | 16.016 h |
| August | 20.6°C14.1°C | 14.1°C | 64 | 9.9 | 14.515 h |
| September | 18.3°C12.2°C | 12.2°C | 62 | 10.2 | 12.713 h |
| October | 14.7°C9.7°C | 9.7°C | 96 | 13.4 | 10.811 h |
| November | 11.0°C6.5°C | 6.5°C | 99 | 13.8 | 9.09 h |
| December | 8.4°C4.3°C | 4.3°C | 92 | 13.4 | 8.08 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Southampton in MayUnited Kingdom · 25 kmHigh 15.9°C · Low 8.8°C · 57 mm rain
- Worthing in MayUnited Kingdom · 50 kmHigh 15.0°C · Low 9.2°C · 47 mm rain
- Basingstoke in MayUnited Kingdom · 52 kmHigh 16.0°C · Low 7.9°C · 59 mm rain
- Bournemouth in MayUnited Kingdom · 56 kmHigh 15.5°C · Low 9.5°C · 51 mm rain
- Guildford in MayUnited Kingdom · 61 kmHigh 16.4°C · Low 8.1°C · 55 mm rain
- Poole in MayUnited Kingdom · 64 kmHigh 15.4°C · Low 9.5°C · 51 mm rain
- Hove in MayUnited Kingdom · 65 kmHigh 14.9°C · Low 9.2°C · 46 mm rain
- Brighton in MayUnited Kingdom · 67 kmHigh 14.9°C · Low 9.1°C · 46 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Portsmouth) is explained once on the Portsmouth year overview and on the Sources, method and limits page.