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 sees moderate rainfall in September, averaging 7 rainy days.
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23
Dry days
7
Rainy days
0
Snow days
23°/10°
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 23° and cooler nights around 10°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Cornwall during September?
In September, Cornwall can expect light to moderate rainfall, totaling 25.6 mm across approximately 7 days. Occasional showers are possible, and planning ahead for them could be helpful.
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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