Climate averages 1991–2020
Terni weather
in September.
A warm, moderately wet month: the 4th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Terni: daytime highs average 25.6°C and nights cool to about 15.0°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 81 mm of rain on roughly 9 days, which makes September a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 32 min on an average September day.
The nearest other city in this atlas is Guidonia Montecelio (64 km away). In September its highs average 25.7°C, about as warm as Terni, with 85 mm of rain.
Among the 79 cities listed in Italy, Terni ranks joint 15th of 79 for the warmest September highs and joint 35th of 79 for the driest September (rainfall, lowest first). The mean September high of those 79 cities is 24.3°C; Terni is 1.4°C warmer than that mean.
From September to October, average highs fall by 5.0°C to 20.7°C, and monthly rainfall rises from 81 mm to 105 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Terni climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 10.5°C2.2°C | 2.2°C | 71 | 9.5 | 9.49 h |
| February | 11.6°C2.2°C | 2.2°C | 82 | 10.0 | 10.511 h |
| March | 15.0°C4.5°C | 4.5°C | 92 | 10.8 | 11.912 h |
| April | 18.4°C7.4°C | 7.4°C | 98 | 13.0 | 13.313 h |
| May | 22.9°C11.4°C | 11.4°C | 83 | 11.3 | 14.615 h |
| June | 27.8°C15.5°C | 15.5°C | 53 | 8.7 | 15.215 h |
| July | 31.4°C18.5°C | 18.5°C | 30 | 5.7 | 15.015 h |
| August | 31.6°C19.0°C | 19.0°C | 33 | 6.1 | 13.914 h |
| September, selected | 25.6°C15.0°C | 15.0°C | 81 | 9.4 | 12.513 h |
| October | 20.7°C11.5°C | 11.5°C | 105 | 10.5 | 11.111 h |
| November | 15.3°C7.2°C | 7.2°C | 129 | 12.4 | 9.810 h |
| December | 11.1°C3.2°C | 3.2°C | 107 | 10.7 | 9.19 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Guidonia Montecelio in SeptemberItaly · 64 kmHigh 25.7°C · Low 15.3°C · 85 mm rain
- Perugia in SeptemberItaly · 64 kmHigh 22.6°C · Low 12.6°C · 79 mm rain
- Rome in SeptemberItaly · 75 kmHigh 25.3°C · Low 16.6°C · 84 mm rain
- Acilia-Castel Fusano-Ostia Antica in SeptemberItaly · 93 kmHigh 24.4°C · Low 18.6°C · 86 mm rain
- Fiumicino in SeptemberItaly · 94 kmHigh 24.2°C · Low 18.9°C · 86 mm rain
- Aprilia in SeptemberItaly · 108 kmHigh 24.4°C · Low 17.6°C · 91 mm rain
- Arezzo in SeptemberItaly · 118 kmHigh 23.9°C · Low 14.4°C · 94 mm rain
- Latina in SeptemberItaly · 124 kmHigh 25.0°C · Low 17.6°C · 88 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Terni) is explained once on the Terni year overview and on the Sources, method and limits page.