Climate averages 1991–2020
Portsmouth weather
in July.
A mild, moderately wet month: the warmest and the joint 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a mild month in Portsmouth: daytime highs average 20.8°C and nights cool to about 14.0°C. By daytime temperature it is the warmest month of the year.
Expect about 52 mm of rain on roughly 10 days, which makes July a moderately wet month (the joint 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 16 h 01 min on an average July day.
The nearest other city in this atlas is Southampton (25 km away). In July its highs average 20.7°C, about as warm as Portsmouth, with 53 mm of rain.
Among the 143 cities listed in the United Kingdom, Portsmouth ranks joint 41st of 143 for the warmest July highs and joint 8th of 143 for the driest July (rainfall, lowest first). The mean July high of those 143 cities is 20.0°C; Portsmouth is 0.8°C warmer than that mean.
From July to August, average highs fall by 0.2°C to 20.6°C, and monthly rainfall rises from 52 mm to 64 mm.
The annual picture
July 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 | 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, selected | 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
July in nearby cities
- Southampton in JulyUnited Kingdom · 25 kmHigh 20.7°C · Low 13.8°C · 53 mm rain
- Worthing in JulyUnited Kingdom · 50 kmHigh 19.8°C · Low 14.2°C · 49 mm rain
- Basingstoke in JulyUnited Kingdom · 52 kmHigh 20.9°C · Low 12.9°C · 58 mm rain
- Bournemouth in JulyUnited Kingdom · 56 kmHigh 20.1°C · Low 14.3°C · 47 mm rain
- Guildford in JulyUnited Kingdom · 61 kmHigh 21.4°C · Low 13.2°C · 57 mm rain
- Poole in JulyUnited Kingdom · 64 kmHigh 20.1°C · Low 14.4°C · 47 mm rain
- Hove in JulyUnited Kingdom · 65 kmHigh 19.6°C · Low 14.1°C · 48 mm rain
- Brighton in JulyUnited Kingdom · 67 kmHigh 19.6°C · Low 14.1°C · 48 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.