The Southern Interior Division extends in a longitudinal belt across the southern portion of the State, and encompasses about 30 percent of Maine's total area. The Northern Interior Division occupies nearly 60 percent of the State's area and has a continental climate. It is furthest from the ocean and contains the highest elevations. Maine has one of the most comfortable statewide summer climates in the continental United States. Summer nights are usually cool and comfortable.
Winters are generally cold, but prolonged cold spells are rare.
Temperature variations are greater in the winter than in summer. Annual precipitation in Maine averages 40 inches in the Northern Division, about 42 inches in the Southern Division and 46 inches in the Coastal Division. Although Maine is rarely subjected to freeze storms, hurricanes, and tornadoes, ten to 20 thunderstorms occur annually in the Coastal Division and 15 to 30 elsewhere. The southern portion of the State has 80 to 120 clear days annually when there is no fog or other precipitation, and northern regions somewhat less. The percentage of possible sunshine varies from 50 percent in Eastport to about 60 percent in Portland.