Climate Portland has a humid continental climate (Köppen: Dfb, closely bordering on Dfa), with cold, snowy, and often prolonged winters, and warm to hot, yet relatively short summers. The monthly average high temperature ranges from roughly in January to around in July. Daily high temperatures reach or exceed on only four days per year on average, while cold-season lows of 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 and is plentiful year-round, but with a slightly drier summer. Annual frozen precipitation (snow) averages in the city. However, this number can fluctuate seasonally from as little as 30 inches to as much as 150 inches, depending on a multitude of factors. In Southern Maine, 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. (although their frequency has increased in recent years). 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 on February 16, 1943, to on July 4, 1911, and August 2, 1975. The hardiness zones are 5b and 6a.
Climate Portland has a humid continental climate (Köppen: Dfb, closely bordering on Dfa), with cold, snowy, and often prolonged winters, and warm to hot, yet relatively short summers. The monthly average high temperature ranges from roughly in January. to around in July. Daily high temperatures reach or exceed on only four days per year on average, while cold-season lows of 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 and is plentiful year-round, but with a slightly drier summer. Annual frozen precipitation (snow) averages in the city. However, this number can fluctuate seasonally from :as little as 30 inches to as much as 150 inches, depending on a multitude of factors. In Southern Maine, 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. (although their frequency has increased in recent years). 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 Nort,h latitude recurve (due to the Coriolis force) and track east out to sea well south of the Portland area. Extreme te.mperatures range from on February 16, 1943, to on July 4, 1911, and August 2, 1975. The hardiness zones are 5b and 6a.