If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Terni: 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.