Portsmouth in Fall
In fall (September, October and November), Portsmouth sees average daytime highs around 14°C and overnight lows near 11°C, with 257 mm of rain over about 37 wet days across the season. It is the 2nd-warmest season and the wettest season of the year.
Over the season highs ease from about 19°C in early September to 10°C by late November. The sky is clear or mostly clear about 18% of the time across fall, and the air most often feels dry.
Fall is Portsmouth's 2nd-best season to visit on our travel score. For the whole year in context, see Portsmouth's year-round climate.
- Avg daytime high
- 14°C
- 2nd-warmest season
- Avg overnight low
- 11°C
- Rainfall
- 257 mm
- 37 wet days
- Avg wind
- 22 km/h
- Travel score
- 4.0
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Portsmouth in Fall
Over the season highs ease from about 19°C in early September to 10°C by late November.
A typical fall day in Portsmouth reaches about 14°C and drops to 11°C overnight. The warmest of the three months is September, the coolest November.
Portsmouth weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 8° / 5° | 84 | 13.4 | 0.6 | 8.2 | 1.3 |
| Feb | 8° / 5° | 60 | 10.5 | 0.5 | 9.7 | 1.2 |
| Mar | 9° / 6° | 50 | 10.1 | 0.3 | 11.5 | 1.9 |
| Apr | 11° / 7° | 52 | 9.7 | 0.1 | 13.5 | 2.9 |
| May | 14° / 10° | 50 | 9.1 | 0 | 15.2 | 4.2 |
| Jun | 17° / 13° | 51 | 9.5 | 0 | 16.2 | 5.4 |
| Jul | 19° / 15° | 52 | 9.6 | 0 | 15.8 | 6.2 |
| Aug | 19° / 15° | 64 | 9.9 | 0 | 14.3 | 6.1 |
| Sep | 18° / 14° | 62 | 10.2 | 0 | 12.4 | 5.6 |
| Oct | 15° / 11° | 96 | 13.4 | 0 | 10.4 | 4.0 |
| Nov | 11° / 8° | 99 | 13.8 | 0 | 8.7 | 2.5 |
| Dec | 9° / 6° | 92 | 13.4 | 0.3 | 7.8 | 1.6 |
Cloud cover in Fall
The sky is clear or mostly clear about 18% of the time across fall.
Chance of precipitation in Fall
Portsmouth gets around 257 mm of rain over 37 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 22 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 h 24 min in early September to 8 h 06 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 2.1 kWh/m².
Is fall a good time to visit Portsmouth?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Portsmouth for sightseeing.
What to pack for Portsmouth in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Portsmouth sees daytime highs around 14°C and nights near 11°C. Pack a warm layer and rain gear. Worth having: a windbreaker. About 37 days see rain.
Sea temperature near Portsmouth in Fall
The nearest coast averages about 15°C across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 19 km away) is warmest in August at about 18°C and coldest in March near 8°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 9 | 8 | 8 | 9 | 11 | 14 | 16 | 18 | 17 | 16 | 13 | 11 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Cool | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 9 | Bracing |
| Feb | 8 | Bracing |
| Mar | 8 | Bracing |
| Apr | 9 | Bracing |
| May | 11 | Bracing |
| Jun | 14 | Bracing |
| Jul | 16 | Cool |
| Aug | 18 | Cool |
| Sep | 17 | Cool |
| Oct | 16 | Cool |
| Nov | 13 | Bracing |
| Dec | 11 | Bracing |
UV index in Portsmouth in Fall
Clear-sky midday UV across fall averages around 3. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Portsmouth peaks around August 11 at about 6 (high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 1 | 3 | 4 | 6 | 6 | 6 | 6 | 4 | 2 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | High | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 1 | Low |
| Mar | 3 | Moderate |
| Apr | 4 | Moderate |
| May | 6 | High |
| Jun | 6 | High |
| Jul | 6 | High |
| Aug | 6 | High |
| Sep | 4 | Moderate |
| Oct | 2 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Where is Portsmouth?
Portsmouth sits at 50.8°N, 1.1°W, 6 m above sea level, in United Kingdom. The nearest listed city is Southsea, 2.0 km away.
Topography around Portsmouth
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Portsmouth.
Within 3 km, the terrain around Portsmouth has only modest variations in elevation — a maximum elevation change of 18 m around an average of 4 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 158 m; within 80 km, significant variations in elevation — a maximum elevation change of 300 m.
The land around Portsmouth is covered by artificial surfaces (50%) and water (35%) within 3 km, water (42%) and grassland (20%) within 16 km, and water (34%), grassland (24%) and trees (21%) within 80 km.
United Kingdom travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type D / G / M
- 230 V · 50 Hz
- Prices
- ≈ 89% of US
- price level, 2025
- GDP per capita
- $57,602
- 2025
- Happiness
- 6.7 / 10
- World Happiness, 2025
- Safe drinking water
- 100%
- of population, 2024
- Homicide rate
- 1.1
- per 100k, 2021
- Road deaths
- 3.2
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Portsmouth (50.799°, -1.0913°, elevation 6 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.