Generally the typical temperate in Porthmadog in September is 13. Through the month the highs are about 17 with low temperatures being around 12 degrees. We have put some more details below:
| Month | Degrees Celsius |
|---|---|
| Temperature | 13 |
| High Temperature | 17 |
| Low Temperature | 12 |
Useful Links: Porthmadog Weather: Average Weather & Yearly Climate