During the summer, evening temperatures can drop into the 40's, and even the 30's in the spring and summer months. Daytime highs generally reach 70's with occassional 80's and 90's. A fair bit of warning with regard to water temperature's along Maine's coast. In late August, the warmest you might find the water is in the 60's - but, expect much cooler water when venturing in. Summer temperatures are a pleasant 70's to 80's with occassional spells of 90's.
Humidity is fairly mild, but occassionally can seem high.
Long dry spells in the summers are rare. Winter months can be very cold, with wind chills in sub-zero ranges. Snow amounts vary thoughout the state - but snow generally begins in November and goes through March. Higher elevations can see low temperatures in the evenings - even during the summer months. Temperatures can range in the 60's and 70's during the summer months.