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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.

  • The climate of Portsmouth in September is notably wet, with an average of 13 rainy days.

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Average dry days
17
Dry days
Average rainy days
13
Rainy days
Average snowy days
0
Snow days
Average temperatures
20°/16°
Temperatures
Average wind speed
26 km/h
Avg max wind
Average humidity
76 %
Avg humidity

Portsmouth in September average weather

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Temperatures trend during September in Portsmouth

See the weather trend as well as the moving average line

September weather day by day

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Date Weather Temperatures Rain UV More
1 Sept. Light rain
Light rain
20° /16° 9.2 mm 5
2 Sept. Light rain shower
Light rain shower
20° /15° 1.5 mm 5
3 Sept. Sunny
Sunny
20° /15° 1.7 mm 5
4 Sept. Sunny
Sunny
20° /15° 2 mm 5
5 Sept. Sunny
Sunny
19° /15° 7.8 mm 5
6 Sept. Sunny
Sunny
21° /17° 9.4 mm 5
7 Sept. Sunny
Sunny
22° /17° 0.5 mm 6
8 Sept. Partly cloudy
Partly cloudy
21° /17° 3.2 mm 5
9 Sept. Partly cloudy
Partly cloudy
21° /16° 0.5 mm 5
10 Sept. Partly cloudy
Partly cloudy
22° /15° 1.6 mm 6
11 Sept. Partly cloudy
Partly cloudy
18° /13° 0.1 mm 5
12 Sept. Overcast
Overcast
17° /12° 0.6 mm 4
13 Sept. Overcast
Overcast
17° /11° 0 mm 5
14 Sept. Partly cloudy
Partly cloudy
17° /12° 0 mm 5
15 Sept. Sunny
Sunny
18° /14° 0 mm 5
16 Sept. Partly cloudy
Partly cloudy
20° /15° 0 mm 6
17 Sept. Light rain shower
Light rain shower
19° /14° 3.5 mm 5
18 Sept. Light rain shower
Light rain shower
21° /14° 3.3 mm 5
19 Sept. Light rain shower
Light rain shower
20° /15° 1.6 mm 5
20 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
19° /15° 10.4 mm 5
21 Sept. Light rain shower
Light rain shower
18° /14° 6.1 mm 4
22 Sept. Light rain shower
Light rain shower
17° /13° 2.6 mm 4
23 Sept. Patchy rain possible
Patchy rain possible
16° /12° 1 mm 4
24 Sept. Overcast
Overcast
18° /14° 1.5 mm 4
25 Sept. Overcast
Overcast
17° /14° 4.6 mm 4
26 Sept. Patchy light rain with thunder
Patchy light rain with thunder
17° /14° 9.9 mm 4
27 Sept. Patchy rain possible
Patchy rain possible
16° /12° 4 mm 4
28 Sept. Patchy rain possible
Patchy rain possible
16° /11° 0.2 mm 4
29 Sept. Overcast
Overcast
16° /12° 2.7 mm 4
30 Sept. Partly cloudy
Partly cloudy
17° /12° 6.6 mm 5
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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?
During September, expect a variety of temperatures with highs around 20° and lows near 16°, suitable for diverse activities and preferences.
How much rainfall should be expected in Portsmouth during September?
Moderate rainfall is anticipated in Portsmouth during September, with a total of 61.5 mm spread over approximately 13 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 26 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 ☀️

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Location coordinates 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.

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