Click on a day for an hourly weather forecast
The temperatures in Cornwall in August are comfortable with low of 15°C and and high up to 25°C.
You can expect rain for roughly half of the month of August in Cornwall. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Cornwall in August 2025.
If you’re planning to visit Cornwall in the near future, we highly recommend that you review the 14 day weather forecast for Cornwall before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -4° / -12° | 11 | 15 | 5 | 27 mm | Awful | Cornwall in January |
| February | -3° / -12° | 10 | 13 | 6 | 29 mm | Awful | Cornwall in February |
| March | 3° / -6° | 9 | 18 | 5 | 30 mm | Awful | Cornwall in March |
| April | 11° / 1° | 8 | 20 | 1 | 41 mm | Ok | Cornwall in April |
| May | 19° / 8° | 8 | 23 | 0 | 39 mm | Good | Cornwall in May |
| June | 22° / 12° | 8 | 22 | 0 | 44 mm | Good | Cornwall in June |
| July | 26° / 16° | 8 | 23 | 0 | 39 mm | Perfect | Cornwall in July |
| August | 25° / 15° | 8 | 23 | 0 | 41 mm | Perfect | Cornwall in August |
| September | 21° / 11° | 7 | 23 | 0 | 37 mm | Good | Cornwall in September |
| October | 14° / 6° | 8 | 23 | 0 | 45 mm | Good | Cornwall in October |
| November | 6° / -1° | 8 | 20 | 2 | 29 mm | Awful | Cornwall in November |
| December | 0° / -6° | 12 | 14 | 5 | 35 mm | Awful | Cornwall in December |