Portland, ME Weather

Portland has a humid continental climate , with cold, snowy, and often prolonged winters, and warm, relatively short summers. The monthly average high temperature ranges from roughly 30 °F (−1 °C) in January to around 80 °F (27 °C) in July. Daily high temperatures reach or exceed 90 °F (32 °C) on only 4 days per year on average, while cold-season lows of 0 °F (−18 °C) or below are reached on 10 nights per year on average. The area can be affected by severe nor’easters during winter, with high winds and snowfall totals often measuring over a foot. Annual liquid precipitation (rain) averages 47.2 inches (1,200 mm) and is plentiful year-round, but with a slightly drier summer. Annual frozen precipitation (snow) averages 69 inches (175 cm) in the city. However, neighborhoods away from the immediate coast average slightly more, as the warmer ocean waters and onshore flow can cause snow to transition to sleet or rain along the coast. In Southern Maine, winter-season snowstorms can be intense from November through early April, while warm-season thunderstorms are somewhat less frequent than in the Midwestern, Mid-Atlantic, and Southeastern U.S. Direct strikes by hurricanes or tropical storms are rare, partially due to the normally cooler Atlantic waters off the Maine coast (which usually weaken tropical systems), but primarily because most tropical systems approaching or reaching 40 degrees North latitude recurve (due to the Coriolis force) and track east out to sea well south of the Portland area. Extreme temperatures range from −39 °F (−39 °C) on February 16, 1943, to 103 °F (39 °C) on July 4, 1911, and August 2, 1975. The hardiness zones are 5b and 6a.