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Weather in Cornwall for September 2025

Your guide to Cornwall weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Cornwall at the beginning of September is 18.7 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 15.7 °C by the end of September.

  • Rain 🌧️

  • Cornwall in September brings notable rainfall, with an average of 19 rainy days and a total precipitation of 89.6 mm.

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Average dry days
11
Dry days
Average rainy days
19
Rainy days
Average snowy days
0
Snow days
Average temperatures
17°/13°
Temperatures
Average wind speed
27 km/h
Avg max wind
Average humidity
80 %
Avg humidity

Cornwall Weather September

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Temperatures trend during September in Cornwall

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. Patchy rain possible
Patchy rain possible
18° /14° 0.3 mm 5
2 Sept. Patchy rain possible
Patchy rain possible
18° /14° 0.8 mm 4
3 Sept. Sunny
Sunny
18° /14° 0.4 mm 5
4 Sept. Sunny
Sunny
19° /15° 0.6 mm 5
5 Sept. Partly cloudy
Partly cloudy
19° /14° 7.5 mm 5
6 Sept. Patchy rain possible
Patchy rain possible
19° /15° 15.4 mm 5
7 Sept. Patchy light rain with thunder
Patchy light rain with thunder
20° /15° 4.4 mm 5
8 Sept. Partly cloudy
Partly cloudy
18° /16° 0.4 mm 5
9 Sept. Partly cloudy
Partly cloudy
19° /15° 0 mm 5
10 Sept. Light rain shower
Light rain shower
19° /14° 3.6 mm 5
11 Sept. Patchy rain possible
Patchy rain possible
16° /13° 1.2 mm 4
12 Sept. Overcast
Overcast
15° /12° 0.4 mm 4
13 Sept. Cloudy
Cloudy
15° /11° 0 mm 4
14 Sept. Overcast
Overcast
17° /11° 0 mm 5
15 Sept. Overcast
Overcast
18° /12° 0 mm 4
16 Sept. Patchy rain possible
Patchy rain possible
20° /14° 0.5 mm 5
17 Sept. Light rain shower
Light rain shower
18° /14° 4.8 mm 5
18 Sept. Light rain shower
Light rain shower
18° /13° 1.3 mm 5
19 Sept. Light drizzle
Light drizzle
19° /14° 0.9 mm 5
20 Sept. Light rain
Light rain
18° /13° 5 mm 4
21 Sept. Light rain shower
Light rain shower
16° /12° 8.1 mm 4
22 Sept. Light rain shower
Light rain shower
16° /12° 5 mm 4
23 Sept. Patchy rain possible
Patchy rain possible
16° /12° 1.2 mm 4
24 Sept. Light rain
Light rain
17° /14° 2.3 mm 4
25 Sept. Patchy rain possible
Patchy rain possible
17° /13° 2.4 mm 4
26 Sept. Light rain shower
Light rain shower
15° /12° 7.5 mm 4
27 Sept. Light rain shower
Light rain shower
15° /11° 3.3 mm 4
28 Sept. Light rain
Light rain
15° /11° 2.5 mm 4
29 Sept. Patchy rain possible
Patchy rain possible
15° /11° 8.4 mm 4
30 Sept. Overcast
Overcast
16° /12° 1 mm 4
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Important Notice
Our weather forecast for Cornwall 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 Cornwall forecast closer to your planned date for the most up-to-date weather information.

Cornwall in September - FAQ

What are the expected maximum and minimum temperatures in Cornwall during September?
Enjoy moderate daytime temperatures of up to 17° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Cornwall during September?
Moderate rainfall is anticipated in Cornwall during September, with a total of 89.6 mm spread over approximately 19 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Cornwall during September?
The average wind speed in Cornwall during September is 27 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Cornwall

Explore the daily rainfall trends and prepare for Cornwalls September weather 💧
Top locations in Cornwall
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Location coordinates Where is Cornwall?

Get accurate weather forecasts for Cornwall, located at latitude 50.416 and longitude -5.073. Stay updated with localized weather information tailored for Cornwall.

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