The climate of New Hampshire
New Hampshire has a humid continental climate (Köppen climate classification Dfb) with warm, humid summers and cold, snowy winters. Vermont in the west, the Canadian provinces of Quebec in the north, Maine and the Atlantic Ocean in the east, and Massachusetts in the south border the state. The climate varies between hot summers (Köppen Dfa) in the south to cold summers and subarctic winters (Köppen Dfc) in the north - the Atlantic Ocean influences the weather in the southeastern part of New Hampshire, while mountain ranges hold sway in the north.
New Hampshire, the Granite State, is home to the White Mountains range that is part of the Appalachian Trail and spreads in the north to the central portion of the state. Mount Washington, Mount Madison and Mount Adams in the range experience some of the most violent winds in the United States. New Hampshire forests are mostly of the temperate broadleaf and mixed type and consist of conifers and northern hardwoods of the New England - Acadian variety. Mixed oaks and northeastern coastal forests adorn the southeastern part of the state. The North Country, which is the northern one-third part of the state, experiences severe cold and heavy snowfall during the winter and has some of the best places in the country to ski and snowboard.
Summers have average daytime highs in the 70°F (21.1°C) to 85°F (29.4°C) range at the peak of July and are warm and humid. Winters have average lows in the -4°F (-20°C) to 15°F (-9.4°C) range in January and are cold, icy and snowy. The northern wilderness regularly drops below 0°F (-17.8°C) during the winter.
Spring and summers produce moderate rain and are prone to thunderstorms. Hurricanes and tornadoes of variable intensity operate from late spring to fall. Snowstorms are frequent during the winter. Strong arctic winds sweep through the Canadian plains and reach unabated to the northern frontiers of New Hampshire. The northern mountain ranges protect the southern part of the state from the cold fronts, and the Atlantic Ocean regulates temperatures in the southeast.
New Hampshire averages an annual rainfall of 40" (1016mm) with significant variations in the White Mountains range and northern highlands. Rain is evenly distributed throughout the year. Snowfall is heavy during the winter and accumulates 60" (1524mm) to 100" (2540mm) statewide with a higher range in the mountains. Nashua recorded New Hampshire's highest temperature of 106°F (41.1°C) on July 4, 1911, while Mount Washington recorded the lowest temperature of -47°F (-43.9°C) on January 29, 1934.
The best time to visit New Hampshire
The best time to visit New Hampshire is during the summer to early fall - from June to September when the temperatures are between moderately warm in the north to hot in the south.
Spring is rainy, cold, and prone to thunderstorms as well as snowstorms. Autumn gets cold by late October, and the conditions are often windy. Summers tend to be temperate, with temperatures rarely crossing 90°F (32.2°C) in the north.
New Hampshire has the smallest ocean coastline in the United States, and tourists flock to Hampton Beach and the White Mountains during the summer. Early fall is the best time to view the beautiful fall foliage and get a few discounts as the tourist season wanes.
The worst time to visit New Hampshire
The late fall and winter season from November to February is the worst time to visit New Hampshire as the state experience severe cold weather and snowy conditions.
Cold fronts are common as early as October, and the first of the snowstorms usually happen by November. Mountain passes and trails are risky to traverse during the winter as they accumulate vast amounts of snow. Winter days are short, and the weak sunlight is available only for a few hours.
Winter is generally an off-season for the family vacation traveler but provides energetic and adventure sports fanatics with one of the best environments for skiing, snowboarding, and many more activities.
New Hampshire is prone to wildfires, thunderstorms, hurricanes, and tornadoes in late spring and summer. Cyclones that originate in the Atlantic Ocean affect the state, and at least two tornadoes every year mark their presence in the state.
Snowstorms are frequent during the winter and turn into blizzards that deposit vast amounts of snow that stalls towns and cities for days. Strong winds and bitter winter cold makes the winters dark and dreary as the roads become routinely impassable amid poor visibility, ice, and snow.
Weather in January
January is usually the coldest month of the year in New Hampshire as the temperatures are in a race towards the bottom. The bottom may hit -25°F (-31.7°C) or even lower in January. The average low temperatures are in the frigid -4°F (-20°C) to 15°F (-9.4°C), while the average high temperatures are in the 14°F (-10°C) to 34°F (1.1°C) zone. The days are short and cold, and the sunlight is meek at the maximum.
January is also the snowiest month of the year and averages 20" (508mm) to 22" (558.8mm) in the state. Mount Washington registers 44" (1117.6mm) as the skiing season reaches its peak. The rugged mountains shine with powdery snow when the humidity and moisture content is low. New England weather is always unpredictable, so expect a few days of moderate sunshine amid the numbing cold.
Do not invite peril by ignoring the weather forecasts, while planning winter visits to New Hampshire - Northeasters, the blizzards of high intensity, often sweep the state during the winter!
Weather in February
February provides no respite to the cold in New Hampshire as the average temperatures are in the cold -2°F (-18.9°C) to 38°F (3.3°C) zone across the state. Berlin in the north averages between a frigid 7°F (-13.9°C) to 30°F (-1.1°C), while Concord, the state capital, in the south, is between a cold 14°F (-10°C) to 35°F (1.7°C).
The sun regularly hides for many days as clouds cover the skies, and the days are short. Freezing temperatures make it difficult to step outside as heaters run for 24 hours a day everywhere, from cars, libraries, and stores to schools and offices. The cold is often unbearable to the naked skin, and warm winter coats are the order of the day.
Snowstorms occur regularly in February, and it is common for schools and offices to close down. It is an excellent idea to have backup power in the form of generators, batteries, or fuel stoves as storms sometimes cause power failures during the winter. At a minimum, keep a stock of warm clothing, food, and fuel.
Weather in March
March is cold in New Hampshire as early spring thaws the winter ice and snow. Day temperatures are a little warm in the 35°F (1.7°C) to 45°F (7.2°C), while the night temperatures plummet to the 15°F (-9.4°C) to 25°F (-3.9°C) range.
March is rainy - the average precipitation in the state is 3" (76.2mm), while the snowfall easily accumulates to 15" (381mm). The weather is moody in spring - sunny days alternate between cloudy, rainy, and cold ones with a few rough ones adding to the mix. Do not expect everything hunky and dory in early spring -, while the days have warmer temperatures than the winter, fresh snow deposits regularly and even sunny days feel cold many times.
Maple sugaring season starts in March as also the renewal of interest in fishing and kayaking with the thawing of snow. The roads and trails appear to be a combination of white, black, and brown, and the trees start to display shades of green. Wear layers of clothing while going outdoors!
Weather in April
April is a wet month during the spring of New Hampshire with warm days and cold nights. The last snow of the season usually disappears by the end of the month and takes the form of rain that averages 4" (101.6mm) to 5" (127mm) in the state. In between sunny days, the humidity drops to the lowest of the year of 62% with the increase in rainfall.
The average high temperatures are between a warm 45°F (7.2°C) to 58°F (14.4°C), while the average night temperatures drop to the cold 28°F (-2.2°C) to 38°F (3.3°C) zone. Durham in the southeast has warm temperatures between 56°F (13.3°C) and 60°F (15.6°C), while the nights rise above freezing and register 32°F (0°C) to 36°F (2.2°C).
The ground changes to a greener texture with the blossoming of flowers on the serene landscape. The tourist season sees a bump in April in the absence of the harsh winter conditions. Be careful while driving, as the roads are slushy with the melting of snow and ice.
Weather in May
May is a beautiful spring month in New Hampshire with comfortably warm weather conditions. The average high temperatures are in the pleasant 60°F (15.6°C) to 70°F (21.1°C), while the nights are in the average range of 40°F (4.4°C) to 45°F (7.2°C).
The chirping of birds, fresh aroma of flowers, freshwater in ponds, lakes, and rivers, and the warmth of the sun creates a brilliant atmosphere full of energy and activity. Biking, hiking, kayaking, fishing, and other activities gather steam in the usually brilliant weather.
Many wet days register in May as the average rainfall is to the tune of 4" (101.6mm) to 5" (127mm).
The ocean water temperature is colder than the land and averages 50°F (10°C) in Portsmouth. Keene in the south averages a warm 42°F (5.6°C) to 70°F (21.1°C), while Colebrook in the north is in the average range of 38°F (3.3°C) to 64°F (17.8°C).
May is an excellent time to beat the summer crowds and enjoy the spring days - the nights require layers of clothing and keep in mind that rain is always unpredictable.
Weather in June
June has one of the best weather conditions in New Hampshire with moderate warmth amid long and mostly sunny days. The average high temperatures are in the wonderful 70°F (21.1°C) to 80°F (26.7°C) range, while average low temperatures are comfortable 50°F (10°C) to 55°F (12.8°C). Laconia in the south is warm and sunny between 55°F (12.8°C) to 76°F (24.4°C), while Plymouth in the north averages between 50°F (10°C) to 75°F (23.9°C).
June sees a few rainy days and thunderstorms occur occasionally. Summer conditions provide pleasant weather in the northern highlands and mountain ranges, which are colder than the southern part of the state.
June weather is ideal for surfing, canoeing, and kayaking in the water. The humidity is tolerable most of the time, as rain is inevitable when it goes high. Summer is also an ideal time for freshwater fishing and hunting, swimming in lakes and ponds, and a variety of outdoor activities. Light clothing is sufficient in the day for people who do not mind a sprinkling of rain.
Weather in July
July is usually the hottest month of the year in New Hampshire with the average high temperatures in the state of 75°F (23.9°C) to 85°F (29.4°C) and the average low temperatures of 55°F (12.8°C) to 65°F (18.3°C). Manchester, the most populated city in New Hampshire, averages 64°F (17.8°C) to 82°F (27.8°C).
Rain is frequent and amounts to 5" (127mm) in the state. Plenty of sunshine and long days are the hallmark of July - the sunset is as late as 9 pm. The temperatures are in the hot zone of 85°F (29.4°C) to 95°F (35°C) at times, but it is rare for the mercury column consistently to touch 100°F (37.8°C).
The ocean temperatures are approximately 60°F (15.6°C), and swimming is pleasant both in the ocean and the lakes - there are many places like Sawyer Rock and Emerald Pool that offer an escape from the crowds of spots like Hampton Beach.
New Hampshire swells with tourists during the summer, and some people prefer to visit during the fall when the foliage is brilliant!
Weather in August
August is a hot summer month in New Hampshire with average high temperatures in the 73°F (22.8°C) to 81°F (27.2°C). Nashua in the south averages between 58°F (14.4°C) to 81°F (27.2°C), while Tamworth in the north is between 50°F (10°C) to 78°F (25.6°C). Conditions are hot in the day, and temperatures frequently cross 90°F (32.2°C).
Rain usually occurs in small bouts and registers a statewide 4" (101.6mm) on an average. August is prone to thunderstorms, particularly in the highlands and the mountain ranges of the north.
Campgrounds are rarely vacant during the summer as the weather is usually bright and sunny most of the time, and the nights are comfortable. It is an excellent idea to carry an insect repellent when camping in open tents during the nights. The hot weather, increased humidity levels and dry spells in between the rains are an invitation to hay fever - people who are allergic to pollens should wait until the conditions subside reasonably by the fall season.
Weather in September
September transitions to the beautiful autumn season with delectably warm temperatures. The atmosphere is damp, and the sun peeks out of the cloud cover now and then. Sunny days are plenty, and the daylight hours are long. The average high temperatures are in the ideal 65°F (18.3°C) to 75°F (23.9°C) range, while the nights are relatively cooler in the average low-temperature range of 45°F (7.2°C) to 55°F (12.8°C).
Summer thunderstorms extend to the early fall season, and there is an outside chance of a hurricane or tornado with its origins in the Atlantic Ocean. Cloudy skies give rise to a maximum humidity of the year of 76% as rain marks its presence regularly in small quantities.
The leaves start to change colors by September as the colorful fall season spreads its wings over New Hampshire. Wildlife is active during the autumn, especially hibernating animals that feed before the winter, and these make for pleasant sightings along with the beautiful flora!
Weather in October
October has warm days and displays peak fall foliage with brilliant shades of red, orange, yellow, magenta, and purple. It is one of the best times to visit New Hampshire to witness the natural beauty of the region with a broad palette of colors amid the backdrop of the panoramic mountains.
Average high temperatures are in the range of 55°F (12.8°C) to 65°F (18.3°C), while average low temperatures register 35°F (1.7°C) to 40°F (4.4°C) across the state. October skies are cloudy and humid, particularly in the second half of the day and rain registers in the range of 4" (101.6mm). Nashua has average temperatures in the 37°F (2.8°C) to 62°F (16.7°C) range, while Lebanon is between 37°F (2.8°C) to 60°F (15.6°C). Days become shorter by the end of October as the daylight is gradually on the wane.
Tourist numbers are up in the peak fall season and along the Kancamagus Highway. Dress in layers of clothing as the temperatures plummet in the evening!
Weather in November
November is the end of the autumn season in New Hampshire and the gateway to the winter with temperatures in the average range of 25°F (-3.9°C) to 50°F (10°C) in the state. Bethlehem in the north averages 24°F (-4.4°C) to 44°F (6.7°C), while Durham in the south is between 31°F (-0.6°C) to 50°F (10°C).
Rain accumulates in the 3" (76.2mm) to 4" (101.6mm) range in the state as November records the first snow of the season. Snowfall is to the tune of an average of 5" (127mm), while the mountains easily surpass 20" (508mm).
Sunny days become increasingly rare, and the sunlight averages a daily 4 hours. The peak of the fall foliage season is over, and many of the trees show bare limbs with the arrival of winter. November witnesses the first snowstorms of the season as the temperatures gradually deteriorate. Nights are in the grip of cold though it is not as severe as the winter.
November is a tourist off-season as it falls between the end of the autumn season and the start of the ski season.
Weather in December
December is cold in New Hampshire with gloomy skies, moderate rain, and abundant snow. The average high temperatures are in the 33°F (0.6°C) to 38°F (3.3°C) range in the south and 27°F (-2.8°C) to 34°F (1.1°C) in the north. The average low temperatures lie in the 15°F (-9.4°C) to 20°F (-6.7°C) zone in the south, while the north is severely cold in the 2°F (-16.7°C) to 15°F (-9.4°C) range. [Resources]
Northern New Hampshire receives heavy snowfall often to the tune of 20" (508mm) and above. The Canadian plains pass on the arctic chill in the form of cold gusts of wind to the northern mountains during the winter. The Atlantic Ocean insulates the southeastern part of the state from extreme cold to an extent by keeping the temperatures in check.
The monthly sunshine rarely crosses 50%, and December has an average of 16 sunny days. Humidity is 70% as New Hampshire receives an average of 3" (76.2mm) to 4" (101.6mm) of rain.
The weather sees fans of winter adventures, but this group is small compared to the majority who prefer to avoid the winter cold.