Weather in Cornwall in September

General weather information about Cornwall

Average annual temperature is 9.4 °C

Absolute maximum temperature: 37.1 °C

Absolute minimum temperature: -13.9 °C

Number of sunny days: 179 days

Number of rainy days: 153 days

Number of snow days: 33 days

Look at detailed online map of Cornwall

* Weather data for Cornwall United States is based on climate observations for 2026 year

Cornwall air temperature forecast for each month

JanFebMarAprMayJunJulAugSepOctNovDec
Absolute maximum temperature (°C)8.68.212.125.428.930.434.737.129.023.912.37.8
Average daytime temperature (°C)2.94.76.412.022.223.730.528.522.115.56.74.3
Average temperature (°C)-0.8-0.11.26.015.217.523.121.715.69.62.61.0
Average night temperature (°C)-3.7-3.4-3.21.49.411.215.715.310.35.5-0.5-1.4
Absolute minimum temperature (°C)-13.9-12.9-11.4-5.23.23.710.79.05.5-6.5-7.9-5.2

Cornwall monthly weather indicators

JanFebMarAprMayJunJulAugSepOctNovDec
Daylight maximum duration (h)9.011.012.014.015.015.015.014.013.011.010.08.0
Daylight mean duration (h)9.010.311.913.615.015.815.414.212.610.99.48.6
Daylight minimum duration (h)8.09.011.012.014.015.014.013.011.010.08.08.0
Sunshine mean duration (h)4.35.87.49.212.513.414.110.99.27.85.24.3
Precipitation (mm)43506476662805432367786
Sunny days1012871617301916181511
Rainy days1410920151311214121518
Snow days7614300000102

Cornwall - weather forecast by months

Cornwall weather in januaryCornwall weather in februaryCornwall weather in marchCornwall weather in aprilCornwall weather in mayCornwall weather in juneCornwall weather in julyCornwall weather in augustCornwall weather in septemberCornwall weather in octoberCornwall weather in novemberCornwall weather in december

Best time to visit Cornwall:

The best time to visit Cornwall during the most sunny months:

  • May — 12.5(h)
  • June — 13.4(h)
  • July — 14.1(h)
  • August — 10.9(h)

Months with the longest average daylight duration in Cornwall:

  • June — 15.8(h)
  • July — 15.4(h)

The largest precipitation sum in Cornwall is at

  • April — 76(mm)
  • May — 66(mm)
  • November — 77(mm)
  • December — 86(mm)

    • Weather forecast in the closest to Cornwall admin centers

    Weather forecast in the closest towns to Cornwall

    Explore Cornwall

    See also
    MapTrains schedule
    Plan your trip
    AccommodationExperiencesBlog

    Frequently asked questions

    When is the best time to visit Cornwall?
    The historical weather data above shows the warmest, sunniest and driest months to help you choose the best time to visit Cornwall.
    What is the weather like in Cornwall?
    See average temperature, rainfall and daylight hours for Cornwall by month in the table above.
    How many sunny days does Cornwall have?
    The monthly weather statistics above show sunshine and rainfall patterns for Cornwall throughout the year.