Portsmouth weather in October
In October, Portsmouth has daytime highs averaging 15 °C, nights around 9.7 °C, with 12 wet days, and a sea temperature of 16 °C. Figures are 1991–2020 climate normals.
- 14.7°C Average high
- 9.7°C Average low
- 12days Wet days
- 78mm Rainfall
- 15.6°C Sea temperature
- 11h Daylight
Daily temperatures through October
How October develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 October | 16.0 °C | 10.8 °C | 40 % |
| 11–20 October | 14.6 °C | 9.5 °C | 33 % |
| 21–31 October | 13.7 °C | 9.1 °C | 42 % |
- Average highs fall from 16.0 °C early in October to 13.7 °C by the end of it.
- Rain is most likely over days 21–31 of October (42 % of days) and least likely over days 11–20 (33 %).
What to expect
| Measure | Typical October | Share of the month |
|---|---|---|
| Days above 25 °C | 0 of 31 | 0 % |
| Days above 30 °C | 0 of 31 | 0 % |
| Days below 0 °C | 0.03 of 31 | 0 % |
| Days with more than 1 mm rain | 12 of 31 | 38 % |
Conditions in October
| Measure | Average |
|---|---|
| Mean temperature | 12 °C |
| Record high (1991–2020) | 24 °C |
| Record low (1991–2020) | -0.4 °C |
| Relative humidity | 81 % |
| Wind speed | 26 km/h |
| Cloud cover | 67 % |
October compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| August | 20.6 °C | 59 mm | 62 % |
| September | 18.3 °C | 54 mm | 62 % |
| October | 14.7 °C | 78 mm | 67 % |
| November | 11.0 °C | 81 mm | 70 % |
| December | 8.5 °C | 77 mm | 71 % |
See all twelve months for Portsmouth
- October is the 6th warmest month here.
- It is the 11th driest month of the year.
- It ranks 7th for least cloud cover.
- Days last about 11 hours from sunrise to sunset.
- It rains on 12 of 31 days — 38 % of the month.
- Nights are about 5.0 °C cooler than the middle of the day.
- The hottest October day on record since 1991 reached 24 °C, 8.9 °C above the usual daytime high.
- Beach score: 15 / 100 — see how this is calculated.
QuestionsOctober in Portsmouth, answered
How warm is Portsmouth in October?
Daily highs average 15 °C and nights fall to about 9.7 °C, a spread of 5.0 °C between afternoon and dawn. That makes October the 6th warmest month of the year here.
Does it rain much in Portsmouth in October?
October averages 78 mm of rain, spread over about 12 of the 31 days — 38 % of the month. Cloud cover averages 67 % of the sky.
Is the sea warm enough to swim in October?
The sea averages 16 °C off Portsmouth in October. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in October?
Portsmouth averages 11 hours between sunrise and sunset in October. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.