Click on a day for an hourly weather forecast
The temperatures in Runcorn in September are usually low and can range between 11°C and 18°C.
You can expect about 3 to 8 days of rain in Runcorn during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Runcorn in September 2025.
If you’re planning to visit Runcorn in the near future, we highly recommend that you review the 14 day weather forecast for Runcorn before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 6° / 2° | 7 | 21 | 3 | 47 mm | Awful | Runcorn in January |
| February | 8° / 2° | 6 | 19 | 3 | 40 mm | Bad | Runcorn in February |
| March | 10° / 3° | 4 | 26 | 1 | 36 mm | Ok | Runcorn in March |
| April | 13° / 5° | 3 | 26 | 0 | 27 mm | Ok | Runcorn in April |
| May | 16° / 7° | 4 | 27 | 0 | 40 mm | Good | Runcorn in May |
| June | 19° / 10° | 5 | 25 | 0 | 51 mm | Good | Runcorn in June |
| July | 20° / 12° | 4 | 27 | 0 | 56 mm | Good | Runcorn in July |
| August | 20° / 12° | 4 | 27 | 0 | 56 mm | Good | Runcorn in August |
| September | 18° / 11° | 3 | 27 | 0 | 40 mm | Good | Runcorn in September |
| October | 14° / 8° | 5 | 26 | 0 | 47 mm | Good | Runcorn in October |
| November | 10° / 5° | 5 | 24 | 0 | 54 mm | Ok | Runcorn in November |
| December | 7° / 3° | 6 | 23 | 2 | 50 mm | Bad | Runcorn in December |