Normally, the average daily temperature in Viterbo right through September is 17 with the high being 25 and typical average low being around 13. The table below has further info:
| Month | Degrees Celsius |
|---|---|
| Temperature | 17 |
| High Temperature | 25 |
| Low Temperature | 13 |
| Sunshine Per Day | 9 |
Useful Links: Viterbo Weather: Average Weather & Yearly Climate