Weather in Maine: Climate, Seasons, and Average Monthly Temperature

Maine Winter Weather - Spring Point Ledge Light, South Portland

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Mark Twain spoke of the "dazzling uncertainty" of New England's weather, and Maine—largest, northernmost, and easternmost of the New England states—takes that variability to extremes. It can be 50 degrees F one moment, snowing the next. It can be rainy along the coast, but a blue-sky perfect hiking day inland. While the weather may toss up surprises hour-to-hour, what Maine vacationers can count on is a sharply defined experience of whichever of the four seasons coincides with their trip. Maine winters are snowy and cold. Spring is an intense time of transition, as sap runs in maple trees and rivers surge with snowmelt. Warm, sun-filled summer days are long, but starry nights still seem to close in too quickly. And autumn in Maine, with its crisp weather and kaleidoscopic color, reliably enchants both Mainers and those "from away."

Consider this: The average annual temperature in far northern Maine is only about 40 degrees F. In the coastal city of Portland, it is just north of 46 degrees. And yet, a handful of 90-degree heatwave days in July and August can make travelers who have come to escape the swelter grumble bitterly. While precipitation is a year-round piece of the weather equation, the Maine coast from Portland south is actually the only locale in the eastern U.S. that receives more wet, sloppy stuff in the winter than rain in the summer.

There is no wrong season to visit Maine: Comfort is a direct factor of packing the correct clothing and gear for the activities you plan to enjoy. It's no wonder L.L. Bean has thrived in Maine for more than a century: Travelers who haven't studied up on the state's variable climate inevitably find themselves in need of an extra cozy layer to wear.

Fast Climate Facts

Note: These temperatures are for Portland, Maine.

  • Hottest Month: July, 79 degrees F
  • Coldest Month: January, 31 degrees F
  • Wettest Month: October and November, 4.9 inches
  • Best Month for Swimming: August, 68 degrees F

Urgent Winter Storm Information

Whether it's feet of snow or a light, slick coating of freezing rain, winter weather can wreak havoc on your Maine travel plans. The Maine Emergency Management Agency posts all watches, warnings, and weather advisories on its website and also shares alerts and useful weather-related travel tips on its Facebook page.

Summer in Maine

From June through August and lingering into September, summer weather makes Maine so popular, you can expect to sit in traffic heading north—particularly on weekends. Maine's beaches and mountains are equally alluring to visitors. Ocean water temperatures never get warmer than what most folks would consider bracing, but kids and brave grownups charge right into Atlantic waves.

Temperatures spike above 90 degrees F on occasion in July or August, so if you're sensitive to heat, be sure to verify whether your hotel or inn has air-conditioning. Quite a few properties, especially historic charmers like Chebeague Island Inn, do not.

Lubec, Maine, is the first U.S. town to greet the sun each day, with sunrise as early as 4:41 a.m. here at the easternmost point in the nation. Don't want to wake early on Maine summer days? A sleep mask can help you catch the zzzs you need.

What to pack: Pack shorts and jeans, T-shirts and long-sleeve shirts, and lightweight extra layers for visits between late June and early September. You'll be thankful for that extra jacket or sweatshirt, particularly if you'll be boating, hiking in the mountains, or stargazing after dark. You'll want bathing suits, towels, and sunscreen if you'll be staying lakeside or oceanside.

Average Temperatures by Month for Portland:

  • June: High: 73 degrees F; Low: 54 degrees F
  • July: High: 79 degrees F; Low: 60 degrees F
  • August: High: 78 degrees F; Low: 59 degrees F

Fall in Maine

By late September, the nighttime cold snaps that trigger leaf color change are starting to occur; progressing from north to south, the Maine landscape takes on its most beautiful appearance of the year. Head away from the shore to Maine's western lakes and mountains for the ultimate leaf-peeping. This is apple-picking, scenic-driving, and giant-pumpkin season, too, and fall festivals are a near constant straight through Halloween. By November, Maine is quiet and gray, and the first snowfall is likely. If you're a bargain seeker, this is the month to visit—after the leaf-peepers have left and before the skiers and snowmobilers claim Maine as their own.

What to pack: Layering is smart, and you'll want warm, cozy sweaters and fleece jackets even while diehards in Boston are still wearing shorts. This is Maine's rainy season—particularly along the coast—so pack an umbrella and raincoat.

Average Temperatures by Month for Portland:

  • September: High: 70 degrees F; Low: 51 degrees F
  • October: High: 59 degrees F; Low: 39 degrees F
  • November: High: 48 degrees; Low: 31 degrees F

Winter in Maine

Winter is Maine's longest season, which is a joyful thing for snow sports enthusiasts. For those who are not, there's no prettying up the fact that it's frozen, cold, and pretty boring up north. That said, there are days when blue skies and white snow make for stunning scenes, and below-zero deep freezes rarely last for long stretches. The sun still rises early, and that means it sets wicked early, too. In Portland in December, you'll wave goodbye to the sun as early as 4:03 p.m.

Coastal resort towns like Kennebunkport and Freeport make an effort to coax winter visitors with events like Paint the Town Red. It may seem unintuitive, but there is a magic to Maine's beaches in the winter, so bundle up for an oceanside stroll along the deserted sands. You might see surfers—really.

What to pack: Snowfall in Maine can be significant, especially in the mountains. Be prepared with a winter coat, scarf, hat, waterproof boots, and gloves if you're visiting between December and March.

Average Temperatures by Month for Portland:

  • December: High: 38 degrees F; Low: 21 degrees F
  • January: High: 32 degrees F; Low: 15 degrees F
  • February: High: 34 degrees F; Low: 16 degrees F
  • March: High: 42 degrees F; Low: 25 degrees F

Spring in Maine

Maine is slow to shake off its frost, but by April, warm days start to muddy the terrain. There is still spring skiing, even as sap for syrup runs in maple trees. In May, whitewater rafting season gets underway on rivers rushing with snow runoff. 

What to pack: You'll want warm clothes for Maine's most unpredictable season, particularly up north where snow is still a possibility in April.

Average Temperatures by Month for Portland:

  • April: High: 53 degrees F; Low: 35 degrees F
  • May: High: 64 degrees F; Low: 45 degrees F
Average Monthly Temperature, Rainfall, and Daylight Hours
Month Avg. Temp. Rainfall Daylight Hours
January 32 F 3.1 in 9 hours
February 34 F 2.7 in 10 hours
March 42 F 3.3 in 11 hours
April 53 F 3.5 in 13 hours
May 64 F 3.7 in 14 hours
June 73 F 4.3 in 15 hours
July 79 F 3.9 in 15.5 hours
August 78 F 3.7 in 14.5 hours
September 70 F 3.7 in 13 hours
October 59 F 4.7 in 11.5 hours
November 48 F 3.9 in 10 hours
December 38 F 4 in 9 hours
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