Planning for the weather is a good way to make your trip to Terni relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 23°C, while the coldest months are January and February, with an average of 6°C. The snowiest months in Terni are March, December, April and February, with each month seeing an average of 32 cm of snowfall.