Usually the weather in Cornwall all through the month of September is 13. You can expect highs around 17 degrees and a low of 12. We have put some more information below:
| Month | Degrees Celsius |
|---|---|
| Temperature | 13 |
| High Temperature | 17 |
| Low Temperature | 12 |
| Sunshine Per Day | 6 |
Useful Links: Cornwall Weather: Average Weather & Yearly Climate