Cornwall
September
Weather in Cornwall for September 2025
Your guide to Cornwall weather in September - trends and predictions
In general, the average temperature in Cornwall at the beginning of September is 25.7 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.4 °C by the end of September.
Cornwall experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 96.5 mm.
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Temperatures
Rain 🌧️
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22
Dry days
8
Rainy days
0
Snow days
22°/11°
Temperatures
13 km/h
Avg max wind
77 %
Avg humidity
Cornwall in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  25° | 2  21° | 3  24° | 4  27° | 5 29° | 6  29° | 7  25° |
| 8 20° | 9  21° | 10 19° | 11 23° | 12 25° | 13  22° | 14 20° |
| 15 24° | 16 24° | 17 24° | 18 23° | 19  22° | 20 23° | 21 22° |
| 22 23° | 23 21° | 24 22° | 25 18° | 26 19° | 27 20° | 28 21° |
| 29 21° | 30 22° |
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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. | Mist | 25° /9° | 3.5 mm | 6 | |
| 2 Sept. | Partly cloudy | 21° /10° | 0.1 mm | 6 | |
| 3 Sept. | Overcast | 24° /11° | 0 mm | 6 | |
| 4 Sept. | Patchy rain possible | 27° /13° | 0.1 mm | 7 | |
| 5 Sept. | Mist | 29° /15° | 0 mm | 7 | |
| 6 Sept. | Sunny | 29° /16° | 0 mm | 7 | |
| 7 Sept. | Moderate or heavy rain shower | 25° /13° | 8.9 mm | 6 | |
| 8 Sept. | Light rain shower | 20° /11° | 2.3 mm | 5 | |
| 9 Sept. | Cloudy | 21° /8° | 0.4 mm | 5 | |
| 10 Sept. | Light rain shower | 19° /9° | 2.2 mm | 5 | |
| 11 Sept. | Fog | 23° /9° | 1.1 mm | 6 | |
| 12 Sept. | Fog | 25° /12° | 0.1 mm | 7 | |
| 13 Sept. | Light rain | 22° /12° | 3.8 mm | 5 | |
| 14 Sept. | Fog | 20° /11° | 0 mm | 5 | |
| 15 Sept. | Partly cloudy | 24° /10° | 0 mm | 6 | |
| 16 Sept. | Overcast | 24° /12° | 0 mm | 6 | |
| 17 Sept. | Overcast | 24° /13° | 0.4 mm | 6 | |
| 18 Sept. | Fog | 23° /12° | 0.4 mm | 6 | |
| 19 Sept. | Thundery outbreaks possible | 22° /12° | 0 mm | 5 | |
| 20 Sept. | Overcast | 23° /9° | 0 mm | 5 | |
| 21 Sept. | Sunny | 22° /8° | 0 mm | 6 | |
| 22 Sept. | Mist | 23° /6° | 0 mm | 5 | |
| 23 Sept. | Overcast | 21° /11° | 0 mm | 5 | |
| 24 Sept. | Fog | 22° /11° | 0 mm | 5 | |
| 25 Sept. | Sunny | 18° /9° | 36.4 mm | 5 | |
| 26 Sept. | Mist | 19° /9° | 36.9 mm | 4 | |
| 27 Sept. | Overcast | 20° /6° | 0 mm | 5 | |
| 28 Sept. | Mist | 21° /9° | 0 mm | 5 | |
| 29 Sept. | Cloudy | 21° /10° | 0 mm | 5 | |
| 30 Sept. | Mist | 22° /12° | 0 mm | 5 | |
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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 22° and cooler nights around 11°. 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 96.5 mm spread over approximately 8 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 13 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 💧
UV exposure in Cornwall during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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