Portsmouth
September
Weather in Portsmouth for September 2025
Your guide to Portsmouth weather in September - trends and predictions
In general, the average temperature in Portsmouth at the beginning of September is 20.3 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 16.7 °C by the end of September.
Portsmouth experiences heavy rainfall in September, with over 20 rainy days and an average total precipitation 96 mm.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
9
Dry days
21
Rainy days
0
Snow days
18°/14°
Temperatures
27 km/h
Avg max wind
76 %
Avg humidity
Portsmouth in September average weather
Move between months or click on a day
| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  20° | 2  20° | 3  20° | 4 20° | 5 19° | 6 21° | 7 22° |
| 8  21° | 9 21° | 10 22° | 11 18° | 12  17° | 13 17° | 14 17° |
| 15 18° | 16 20° | 17 19° | 18 21° | 19 20° | 20  19° | 21 18° |
| 22 17° | 23 16° | 24 18° | 25 17° | 26  17° | 27 16° | 28 16° |
| 29 16° | 30 17° |
You can click on date
Access Portsmouth weather forecasts with a simple click. Select any date for comprehensive insights on temperature, rainfall, and wind conditions.
Temperatures trend during September in Portsmouth
See the weather trend as well as the moving average line
September weather day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Light rain | 20° /16° | 9.2 mm | 5 | |
| 2 Sept. | Light rain shower | 20° /15° | 1.5 mm | 5 | |
| 3 Sept. | Sunny | 20° /15° | 1.7 mm | 5 | |
| 4 Sept. | Sunny | 20° /15° | 2 mm | 5 | |
| 5 Sept. | Sunny | 19° /15° | 7.8 mm | 5 | |
| 6 Sept. | Sunny | 21° /17° | 9.4 mm | 5 | |
| 7 Sept. | Sunny | 22° /17° | 0.5 mm | 6 | |
| 8 Sept. | Partly cloudy | 21° /17° | 3.2 mm | 5 | |
| 9 Sept. | Partly cloudy | 21° /16° | 0.5 mm | 5 | |
| 10 Sept. | Partly cloudy | 22° /15° | 1.6 mm | 6 | |
| 11 Sept. | Partly cloudy | 18° /13° | 0.1 mm | 5 | |
| 12 Sept. | Overcast | 17° /12° | 0.6 mm | 4 | |
| 13 Sept. | Overcast | 17° /11° | 0 mm | 5 | |
| 14 Sept. | Partly cloudy | 17° /12° | 0 mm | 5 | |
| 15 Sept. | Sunny | 18° /14° | 0 mm | 5 | |
| 16 Sept. | Partly cloudy | 20° /15° | 0 mm | 6 | |
| 17 Sept. | Light rain shower | 19° /14° | 3.5 mm | 5 | |
| 18 Sept. | Light rain shower | 21° /14° | 3.3 mm | 5 | |
| 19 Sept. | Light rain shower | 20° /15° | 1.6 mm | 5 | |
| 20 Sept. | Moderate or heavy rain shower | 19° /15° | 10.4 mm | 5 | |
| 21 Sept. | Light rain shower | 18° /14° | 6.1 mm | 4 | |
| 22 Sept. | Light rain shower | 17° /13° | 2.6 mm | 4 | |
| 23 Sept. | Patchy rain possible | 16° /12° | 1 mm | 4 | |
| 24 Sept. | Overcast | 18° /14° | 1.5 mm | 4 | |
| 25 Sept. | Overcast | 17° /14° | 4.6 mm | 4 | |
| 26 Sept. | Patchy light rain with thunder | 17° /14° | 9.9 mm | 4 | |
| 27 Sept. | Patchy rain possible | 16° /12° | 4 mm | 4 | |
| 28 Sept. | Patchy rain possible | 16° /11° | 0.2 mm | 4 | |
| 29 Sept. | Overcast | 16° /12° | 2.7 mm | 4 | |
| 30 Sept. | Partly cloudy | 17° /12° | 6.6 mm | 5 | |
| Next | |||||
Important Notice
Our weather forecast for Portsmouth in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Portsmouth forecast closer to your planned date for the most up-to-date weather information.
Portsmouth in September - FAQ
What are the expected maximum and minimum temperatures in Portsmouth during September?
Enjoy moderate daytime temperatures of up to 18° and cooler nights around 14°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Portsmouth during September?
Moderate rainfall is anticipated in Portsmouth during September, with a total of 96 mm spread over approximately 21 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Portsmouth during September?
The average wind speed in Portsmouth during September is 27 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Portsmouth
Explore the daily rainfall trends and prepare for Portsmouths September weather 💧
UV exposure in Portsmouth during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Quick links
You are here
Where is Portsmouth?Get accurate weather forecasts for Portsmouth, located at latitude 50.799 and longitude -1.091. Stay updated with localized weather information tailored for Portsmouth.
Related locations
Select a location for accurate weather forecast
More Locations Found a mistake?
We appreciate your attention to details. Tell us here.