Temperatures in September
It's hot in September in Cornwall with an average temperature of 32°C. Temperatures this month range from a low of 32°C to a high of 33°C. At night, you can expect temperatures between 26°C and 27°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Cornwall in September. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of September
The month of September starts in Cornwall with hot temperatures, averaging around 33°C during the day and nights close to 27°C. You can expect regular precipitation, but there’s also a chance for some sunny days in the first days of the month. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal.
Mid-September
By mid-September, the average daytime temperature drops to around 32°C, with nights close to 27°C. There might be a few showers during this period, but plenty of dry days with sunshine too. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal.
End of September
By the end of September, the average daytime temperature in Cornwall will be around 32°C, with nights close to 27°C. There’s regular precipitation, but with a bit of luck, you’ll also get some dry and sunny days. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal.
Precipitation in September
In September, there is an average of 107 mm of precipitation, spread over 9 days. The wind speed is around 4 Bft, mostly coming from the East.
The average precipitation chance is 30% per day this month. Though it seems pretty low, the weather’s variable. Some days have higher and others lower precipitation chances, which lowers the average.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for Cornwall. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Cornwall in September |
London | ||
|---|---|---|---|
 Average Temperature |
32°C | 20°C | |
 High Temp |
33°C | 22°C | |
| Low Temp |
32°C | 17°C | |
 Total Precipitation |
107 mm | 44 mm | |
| Rainy Days |
9 days | 8 days | |
August
UV index
The UV index is a maximum of 9 this month. That's a very high value on the intensity scale of 1 to 11. Unprotected skin can burn within 10-15 minutes.
Is September a good time to visit Cornwall?
After some sun? Then September isn’t the best time to be in Cornwall. The temperature is pleasant, but there’s too much chance of rain this month.
The hurricane season in Cornwall runs from June to November.
Temperature records for Cornwall in September
With 35°C, Cornwall hit the highest temperature in the last 10 years in September 2019. The lowest daytime temperature in this month was 28°C in 2023. The extreme night temperatures ranged from a low of 22°C to a high of 29°C.
Check out the climate of Cornwall for all months and discover the best travel time
Daily Temperature in September in Cornwall
This chart shows the average daily temperatures, both day and night, for each day in September in Cornwall, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in Cornwall
The chart below shows the average daily precipitation in September for Cornwall, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect around 9 days of rain in Cornwall.
Daily UV Index in September in Cornwall
This chart shows the average daily UV index in September in Cornwall, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Cornwall Over the Years
This chart shows the average temperature in September in Cornwall, measured in degrees Celsius, over the past years.
Total Precipitation in September in Cornwall Over the Years
This chart shows the average precipitation in September in Cornwall, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for Cornwall
Click on a specific day in September for detailed info on the typical weather on that day in Cornwall. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Cornwall
Have you been to Cornwall in September?
Share your weather experience in September in Cornwall.
Average Weather in Cornwall by Month
Click on a month below to see detailed weather info for Cornwall. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
