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Weather in Cornwall for September 2026

Your guide to Cornwall weather in September - trends and predictions

    Temperatures

  • In general, the average temperature in Cornwall at the beginning of September is 25.1 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 21 °C by the end of September.

    • Rain 🌧️

  • Cornwall experiences moderate rainfall in September, with an average of 10 rainy days and a total precipitation of 137.5 mm.

    • More

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Average dry days
20
Dry days
Average rainy days
10
Rainy days
Average snowy days
0
Snow days
Average temperatures
22°/11°
Temperatures
Average wind speed
13 km/h
Avg max wind
Average humidity
74 %
Avg humidity

Cornwall Weather September

Move between months or click on a day
August
October
Mon.Tue.Wed.Thu.Fri.Sat.Sun.
1
Mist
26°
2
Partly cloudy
23°
3
Overcast
24°
4
Patchy rain possible
27°
5
Mist
27°
6
Sunny
26°
7
Moderate or heavy rain shower
23°
8
Light rain shower
20°
9
Cloudy
22°
10
Sunny
22°
11
Fog
23°
12
Partly cloudy
24°
13
Light rain
20°
14
Fog
21°
15
Partly cloudy
24°
16
Overcast
25°
17
Overcast
25°
18
Fog
24°
19
Thundery outbreaks possible
21°
20
Overcast
21°
21
Sunny
23°
22
Mist
22°
23
Overcast
21°
24
Fog
22°
25
Sunny
18°
26
Mist
21°
27
Overcast
20°
28
Mist
22°
29
Cloudy
23°
30
Mist
21°

Temperatures trend during September in Cornwall

See the weather trend as well as the moving average line

September weather in Cornwall day by day

Click on a date for more information
August October
Date Weather Temperatures Rain UV More
1 Sept. Mist
Mist
 26° /10° 2.4 mm 6
2 Sept. Partly cloudy
Partly cloudy
 23° /11° 0 mm 6
3 Sept. Overcast
Overcast
 24° /12° 0 mm 6
4 Sept. Patchy rain possible
Patchy rain possible
 27° /14° 17 mm 6
5 Sept. Mist
Mist
 27° /13° 0 mm 6
6 Sept. Sunny
Sunny
 26° /15° 6.8 mm 6
7 Sept. Moderate or heavy rain shower
Moderate or heavy rain shower
 23° /12° 6 mm 5
8 Sept. Light rain shower
Light rain shower
 20° /10° 1.5 mm 4
9 Sept. Cloudy
Cloudy
 22° /8° 0.3 mm 5
10 Sept. Sunny
Sunny
 22° /9° 1.4 mm 6
11 Sept. Fog
Fog
 23° /11° 0.8 mm 5
12 Sept. Partly cloudy
Partly cloudy
 24° /11° 0.1 mm 6
13 Sept. Light rain
Light rain
 20° /11° 4.9 mm 5
14 Sept. Fog
Fog
 21° /12° 0.9 mm 5
15 Sept. Partly cloudy
Partly cloudy
 24° /11° 0 mm 6
16 Sept. Overcast
Overcast
 25° /11° 0 mm 6
17 Sept. Overcast
Overcast
 25° /12° 0.3 mm 6
18 Sept. Fog
Fog
 24° /13° 0.3 mm 6
19 Sept. Thundery outbreaks possible
Thundery outbreaks possible
 21° /10° 0 mm 4
20 Sept. Overcast
Overcast
 21° /6° 0 mm 5
21 Sept. Sunny
Sunny
 23° /6° 0 mm 6
22 Sept. Mist
Mist
 22° /7° 0.2 mm 5
23 Sept. Overcast
Overcast
 21° /12° 2.4 mm 5
24 Sept. Fog
Fog
 22° /12° 0 mm 5
25 Sept. Sunny
Sunny
 18° /11° 67.9 mm 5
26 Sept. Mist
Mist
 21° /11° 24.6 mm 4
27 Sept. Overcast
Overcast
 20° /6° 0 mm 5
28 Sept. Mist
Mist
 22° /11° 0 mm 5
29 Sept. Cloudy
Cloudy
 23° /11° 0 mm 5
30 Sept. Mist
Mist
 21° /11° 0 mm 5
Next
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 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?

Significant rainfall exceeding 137.5 mm is expected in Cornwall during September, occurring over more than 10 days. Preparing for wet conditions is recommended in your planning.

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 💧
Typically, Cornwall has 10 rainy days in September with a total of 137.5 mm of rainfall.

UV exposure in Cornwall during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️

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Location coordinates Where is Cornwall?

Get accurate weather forecasts for Cornwall, located at latitude 45.018 and longitude -74.728. Stay updated with localized weather information tailored for Cornwall.

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