Cornwall (Newquay)
September
Weather in Cornwall for September 2026
Your guide to Cornwall weather in September - trends and predictions
In general, the average temperature in Cornwall at the beginning of September is 18.4 °C. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 15.6 °C by the end of September.
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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Temperatures
Rain 🌧️
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11
Dry days
19
Rainy days
0
Snow days
17°/13°
Temperatures
27 km/h
Avg max wind
80 %
Avg humidity
Cornwall Weather September
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Temperatures trend during September in Cornwall
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September weather in Cornwall day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Patchy rain possible | 18° /14° | 3.3 mm | 4 | |
| 2 Sept. |  Light drizzle | 18° /13° | 3.7 mm | 4 | |
| 3 Sept. |  Sunny | 18° /14° | 3.5 mm | 5 | |
| 4 Sept. | Sunny | 19° /14° | 4.6 mm | 5 | |
| 5 Sept. |  Partly cloudy | 18° /14° | 5.2 mm | 5 | |
| 6 Sept. | Patchy rain possible | 19° /15° | 10.2 mm | 5 | |
| 7 Sept. |  Patchy light rain with thunder | 19° /14° | 5.2 mm | 4 | |
| 8 Sept. | Partly cloudy | 18° /15° | 1 mm | 5 | |
| 9 Sept. | Partly cloudy | 18° /14° | 6.4 mm | 4 | |
| 10 Sept. | Light rain shower | 18° /14° | 3.7 mm | 4 | |
| 11 Sept. | Patchy rain possible | 16° /13° | 2.9 mm | 4 | |
| 12 Sept. |  Overcast | 15° /12° | 3.7 mm | 4 | |
| 13 Sept. |  Cloudy | 15° /11° | 2.1 mm | 4 | |
| 14 Sept. | Overcast | 17° /11° | 1.9 mm | 4 | |
| 15 Sept. | Overcast | 17° /12° | 1.1 mm | 4 | |
| 16 Sept. | Patchy rain possible | 18° /13° | 0.9 mm | 5 | |
| 17 Sept. | Light rain shower | 18° /14° | 3.6 mm | 4 | |
| 18 Sept. | Light rain shower | 19° /13° | 0.9 mm | 5 | |
| 19 Sept. | Partly cloudy | 19° /14° | 0.6 mm | 5 | |
| 20 Sept. | Light rain | 17° /13° | 7.3 mm | 4 | |
| 21 Sept. | Light rain shower | 15° /11° | 7.1 mm | 3 | |
| 22 Sept. | Light rain shower | 15° /10° | 3.3 mm | 4 | |
| 23 Sept. | Patchy rain possible | 15° /11° | 0.8 mm | 4 | |
| 24 Sept. | Patchy rain possible | 16° /12° | 1.6 mm | 4 | |
| 25 Sept. | Patchy rain possible | 17° /12° | 1.6 mm | 4 | |
| 26 Sept. | Light rain shower | 15° /11° | 5 mm | 4 | |
| 27 Sept. | Light rain shower | 15° /11° | 2.9 mm | 3 | |
| 28 Sept. | Light rain | 15° /11° | 1.7 mm | 4 | |
| 29 Sept. | Patchy rain possible | 15° /11° | 5.6 mm | 4 | |
| 30 Sept. | Overcast | 16° /11° | 0.6 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.
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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.
Cornwall water temperatures in September
The average water temperature of the Atlantic Ocean near Cornwall in September is 15.5 °C. At the beginning of September temperatures are around 15.7 °C; by the end of the month they stay fairly steady and reach 15.3 °C.
- What is the water temperature in Cornwall in September?
- The average water temperature in Cornwall in September is 15.5 °C.
- Can you swim in Cornwall in September?
- Brisk: quick dips and active swimming are fine, but pack a 2–3 mm spring suit if you plan longer sessions or early-morning outings.
September rainfall patterns in Cornwall
Explore the daily rainfall trends and prepare for Cornwalls September weather 💧
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