Connecticut climate ranges from humid continental type (Köppen climate classification Dfa, Dfb) in the north to humid subtropical (Köppen Cfa, Cfb) in the south. Summers are hot and humid, while winters range from mild on the coast to cold and snowy in the interior. Connecticut lies in the southwestern New England region, which is the northeastern part of the United States. Rhode Island in the east, Long Island Sound in the south, New York in the west, and Massachusetts in the north border the state. The climate varies by region, and there is little influence of geographical factors other than the water bodies in the south.
Connecticut, the Constitution State, has an average elevation of 150 meters above sea level with the highest point at 725 meters on the south slope of Mount Frissell on the border. The Connecticut River nearly bisects the state before flowing into the Long Island Sound in the south. The diverse topography consists of rolling hills and farms in the north to coastal marshes and beaches in the east. Northern hardwood, conifers, oak, spruce, and maple form the majority of the forests in the state. New England-Acadian forests are rife in the northwest, while northeastern coastal forests constitute parts of the south and east.
Spring has slightly cool to warm temperatures in Connecticut, and the heat increases by the later part of the season. The Bermuda High brings hot weather conditions from May to 8register peak temperatures during July. Average high temperatures reach 85°F (29.4°C) in summer, while heat waves occasionally push temperatures above 100°F (37.8°C). Thunderstorms are frequent in late spring and summer, often accompanied by lightning and thunder. An occasional tornado invades the state in the storm season. Hurricanes rarely hit the state directly. Fall is mild to cold with colorful foliage that moves quickly from the north to the south. Winters are cold, with average low temperatures between 1°F (-17.2°C) to 3°F (-16.1°C) at the peak of January.
The rainfall in Connecticut is fairly even throughout the year and averages in the range of 44" (1117.6mm) to 48" (1219.2mm) annually. Significant differences occur in precipitation between two topographically different places just a few miles away. Snowfall averages from a yearly 20" (508mm) in the south and east, to 60" (1524mm) in the northern hilly regions. Higher elevations have recorded snowfall above 150" (3810mm) in unusually cold winter. Annual sunshine averages 2500 hours, with the sunniest period between June and August. The percentage of possible annual sunshine ranges from 45% to 65%, with 100 to 125 clear days in the year. Humidity is the lowest in the spring and highest in late summer and early fall.
Danbury recorded Connecticut's highest ever temperature of 106°F (41.1°C) on July 15, 1995, while Falls Village recorded the coldest temperature of -32°F (-35.6°C) on February 16, 1943.
The best time to visit Connecticut
The best time to visit Connecticut is from mid-May to mid-October that encompasses the period of late spring to mid-autumn. Late spring has warm temperatures with day temperatures in the 65°F (18.3°C) to 70°F (21.1°C) range. May is warm with unexpected rain as well as bright sunshine. Summers are hot and humid but rarely go past 100°F (37.8°C). The fall season has pleasant temperatures from September to early November. The peak foliage displays in the mid of October with spectacular hues in the high country. Summer crowds disperse by the beginning of September, but there are many visitors in the fall season.
The worst time to visit Connecticut
The worst time to visit Connecticut is during the winter season from December to February when the cold is at its peak. Cold fronts from the Canadian North frequently invade the state with night temperatures often dropping below 0°F (-17.8°C). Snowfall is heavy in the winter and blizzards add to the snow depth. Wintry conditions make roads slippery with the frequent invasion of black ice. Heavy fog descends in the coastal regions during late winter. The cold season sees low footfall in Connecticut except those of snow lovers.
Connecticut is prone to thunderstorms in spring and early summer. Lightning and rain often accompany the storms, with occasional casualties. Late spring is also prone to flooding with the thawing of snow and heavy rain. Snowstorms are frequent in the winter, deposit large amounts of snow, and stall everyday life for many days. Violent storms last for a while and create icy conditions with a severe drop in visibility. Fallen trees on power lines are the most common cause of power outage during such periods. Nor'easters are the most significant hazard with strong winds, heavy rainfall, and snowfall. Storms during high tide cause heavy damage along the shore.
Weather in January
January is usually the coldest and snowiest month of the year with the arrival of the New Year in Connecticut. The average temperatures are in the cold zone of 13°F (-10.6°C) to 39°F (3.9°C), with Hartford, the capital between 18°F (-7.8°C) to 35°F (1.7°C). The rainfall is moderate in the 3" (76.2mm) to 4" (101.6mm) range, but the snowfall is ample, especially in the interior of the state where it ranges from 10" (254mm) to 20" (508mm). Coastal regions typically do not see snow lying on the ground for more than a few days after a snowstorm. Snowplows are regularly in action to clear the roads and highways, and drivers need to spot them from a distance to avoid collisions. Plan activities in advance and keep plenty of buffer time in the winter. It is an excellent idea to put snow tires on vehicles in the icy conditions, and tire chains are better for hilly roads. A Connecticut trip in January is rarely to avail of a vacation.
Weather in February
February is the driest month of the year in Connecticut as the cold holds the state in its sway. The precipitation drops in the range of 2" (50.8mm) to 3" (76.2mm), but the skies remain gloomy in the winter. The average temperatures statewide are in the 15°F (-9.4°C) to 42°F (5.6°C) zone with Bridgeport and New Haven registering between 25°F (-3.9°C) to 41°F (5°C). The nights are bitterly cold and routinely drop below 0°F (-17.8°C) in the interior regions. Stamford, in the coastal area of the southwest panhandle, receives 9" (228.6mm) of snow, one of the highest amounts along the coast. Wind chill often adds to the cold as it becomes challenging to stay outdoors in the freezing atmosphere. Snowstorms are frequent, as sidewalks, roads, driveways, and vehicles need time to be serviceable after a hefty deposit of snow. The unpredictable weather can throw a few sunny days in the mix when people are confident that the cold will remain at its peak. Keep an eye on the weather for storms in February in Connecticut.
Weather in March
March is cold in Connecticut, with the transition from winter to spring in the second half of the month. The average high temperatures are in the cold 45°F (7.2°C) to 50°F (10°C) range, while the average low temperatures are in the freezing zone of 22°F (-5.6°C) to 32°F (0°C). Mornings dawn with a promise of sunny afternoons, but frequently fade into cold evenings and frosty nights. The snow covers the ground in the interior, while the coast rarely sees a frozen landscape. Precipitation is to the tune of 3" (76.2mm) to 5" (127mm), and the snowfall in the range of 5" (127mm) to 8" (203.2mm) attracts many followers. New Haven along the coast registers temperatures between 31°F (-0.6°C) to 48°F (8.9°C), while Burlington in the interior is cold between 26°F (-3.3°C) to 47°F (8.3°C). Winter coats are very much in vogue as cold fronts from the Canadian north routinely make way to the interior. The daylight improves steadily as the spring season knocks the doors of Connecticut in late March.
Weather in April
April brings the first signs of warmth in Connecticut with the advance of the spring season. The weather is unpredictable as the rest of New England with sunny periods between patches of wet weather. Temperatures fare better during the day between 54°F (12.2°C) to 64°F (17.8°C), while the nights ascend above freezing to register in the 34°F (1.1°C) to 42°F (5.6°C). Rain is persistent during early spring and makes it mandatory to carry a rain jacket or an umbrella for outdoor visits. An odd snowstorm strikes the state to deposit large amounts of snow and stall in everyday life. Black ice is hazardous while driving over the mushy roads in the wet conditions. Nevertheless, spring brings blooming wildflowers, a green landscape, and cheerful sounds of birds and animals. Fishing rods and boats find their way towards the lakes and rivers, as the thawing of the snow provides abundant freshwater for the aquatic species. Expect the temperatures to rise steadily with each passing day in April in Connecticut.
Weather in May
May is a beautiful spring month in Connecticut with many sunny days and pleasant conditions. Late spring sees average high temperatures in the warm 65°F (18.3°C) to 73°F (22.8°C) zone and average low temperatures in the mild 44°F (6.7°C) to 50°F (10°C). The rainfall is to the tune of 3" (76.2mm) to 4" (101.6mm) but is in the form of light showers most of the time. Danbury in the interior registers temperatures in the 48°F (8.9°C) to 72°F (22.2°C) zone, while New London along the coast is between 48°F (8.9°C) to 65°F (18.3°C). The ocean waters are mild, and the season is perfect for the sighting of whales and long-distance cruises. Sunny days are ample, along with periods of light rain. Light sweaters and rain jackets protect from a downturn in weather and wetness. The fresh air of spring brings the smell of the aromatic soil and the blossoming flowers in the atmosphere. Spring festivals rule the roost in the joyous days of May in Connecticut.
Weather in June
June is the beginning of the summer season in Connecticut, with warm temperatures amid 9 hours of daily sunshine. The days are long, but the brightest season of the year is prone to frequently moist periods. Rainfall is to the tune of 3" (76.2mm) to 4" (101.6mm), with 10 to 12 days of wet weather. Day temperatures bask in the glorious sunshine to register in the range of 73°F (22.8°C) to 81°F (27.2°C). Humidity is at the highest in the mornings and decreases steadily. Nights are comfortable with temperatures between 54°F (12.2°C) to 60°F (15.6°C). Ocean waters are warm and draw crowds to the beaches along the coast in Bridgeport, Groton, New London, and the like. Summer is an ideal time for vacation and the short period when conditions are suitable to wear light clothing like sweatshirts, t-shirts, and shorts. Mornings and evenings are the best time for outdoor activities. Expect the temperatures to rise further with each passing day in June in Connecticut.
Weather in July
July is by far the hottest month of the year in Connecticut, with the average high temperatures in the 78°F (25.6°C) to 85°F (29.4°C) range. The heat is oppressive at times, particularly in inland areas like Hartford and Danbury, where the temperatures regularly cross 90°F (32.2°C). Nights are in the 55°F (12.8°C) to 65°F (18.3°C) range, but the humidity that is high during the day many a time persists in the evenings. A large number of beaches due to the Long Island Sound spanning the entire south of the state see a flurry of activities with the arrival of the summer crowd. The 3" (76.2mm) to 5" (127mm) of rain is mainly from thunderstorms that are dominant in the afternoons. Early mornings have moderate sunshine suitable for biking, kayaking, and fishing. Late afternoons and evenings experience a brisk wind from the ocean. Sweatshirts are comfortable during the day when the humidity is at the peak. The late sunset is a surprise to many tourists as there is still daylight at 9 p.m. July is an excellent time to visit Connecticut.
Weather in August
August lies in the hot summer of Connecticut, with long periods of clear skies and sunshine. The mercury column is in the average range of 57°F (13.9°C) to 84°F (28.9°C) with long days and high humidity. Norwich and Stamford in the coastal area register slightly higher temperatures than the interior, between 61°F (16.1°C) to 84°F (28.9°C). Light to moderate showers occur in the majority of the state but rarely last for long periods. Hilly areas and lakes provide refreshingly cold conditions and serve as weekend getaways and picnic spots. The mild ocean waters serve as a source of clams and lobsters as well as thermal regulators. Expect the temperatures to decrease by the fourth week of August steadily. A neat idea to beat the summer heat is to visit the local casinos. Aquariums and museums provide plenty of indoor amusement during the hot afternoons. The weather is anything but constant, yet springs a surprise now and then. Light summer clothing is best in August in Connecticut.
Weather in September
September is the beginning of the colorful fall season in Connecticut with moderate temperatures. The average high temperatures are in the pleasant 68°F (20°C) to 76°F (24.4°C) range, while the average low temperatures are in the mild 48°F (8.9°C) to 54°F (12.2°C) zone. New Haven on the coast registers temperatures between 56°F (13.3°C) to 74°F (23.3°C), while Norfolk in the interior is one of the coldest places in the state between 50°F (10°C) to 68°F (20°C). The skies are partly cloudy, but the daily sunshine is rarely short of 7 hours. Back roads, state parks, and forests, rivers, and lakes are the ideal places for experience the fall foliage, which begins by the third week of September. Autumn is apple season and also the time of pumpkin patches and corn mazes. Full-sleeved clothing is better during the breezy evenings with a drop in temperatures and the ever-present threat of rain. Wind speeds rarely cross 10mph (16.1km/h), but a jacket is handy in Connecticut in September.
Weather in October
October is the time of the peak fall foliage in Connecticut. Oaks, spruces, maples, and hardwoods have their distinct hues of yellow, orange, red, and gold. By mid-October, the colors move to cover the entire area from the north to the south. The average temperatures are in the mild 41°F (5°C) to warm 65°F (18.3°C), with 3" (76.2mm) to 5" (127mm) of rainfall in the majority of the state. The harvest season is in its last legs, with a steady increase in the cold. Wildlife is busy accumulating every additional scrap of food to prepare for the harsh winter ahead. Fall experience is spectacular while hiking and biking over the narrow roads in the backcountry. Expect temperatures to drop steadily by the end of October. Cold nights become cozy in the warm comfort of a romantic fireplace in a bed and breakfast inn. October is one of the best times to visit Connecticut and drive through the scenic byways with the wind in the face.
Weather in November
November brings the last days of the autumn season in Connecticut with a steady buildup a cold. The skies are partly cloudy, and the days are short. The daily sunshine is at the lowest of the year at less than 5 hours. The average low temperatures are in the cold 29°F (-1.7°C) to 38°F (3.3°C) range, while the average high temperatures are in the mild zone of 45°F (7.2°C) to 54°F (12.2°C). Bridgeport on the coast is mild between 33°F (0.6°C) to 54°F (12.2°C), while Middletown in the interior registers temperatures in the 29°F (-1.7°C) to 52°F (11.1°C) zone. The fall foliage is past its peak in the north and recedes steadily in the south. Precipitation is to the tune of 3" (76.2mm) to 4" (101.6mm), with frequently darks skies being the common theme in the evenings. The first snow of the season usually arrives by mid-November and is to the tune of 4" (101.6mm) in Norfolk. The cold nights are unappealing to out of state visitors, especially from the warm southern states. Watch out for the first of the snowstorms by the last week of November in Connecticut.
Weather in December
December is the beginning of the icy winter in Connecticut, with the average temperatures in the 20°F (-6.7°C) to 44°F (6.7°C) range. Cold fronts occasionally push the temperatures below 0°F (-17.8°C) as gray skies rule the roost. Nights vary by 5°F (-15°C) or more between the interior and the coastal regions. Groton on the coast registers between 28°F (-2.2°C) to 44°F (6.7°C), while West Thompson Lake in the interior is between 20°F (-6.7°C) to 34°F (1.1°C). Ten to fifteen days in December yield 3" (76.2mm) to 5" (127mm) of rain, but the 6" (152.4mm) to 8" (203.2mm) of snowfall makes the roads slippery and the month unfavorable for visitors. The snowfall varies by region and registers as high as 16" (406.4mm) in Norfolk. The ocean water is cold and uninviting in the winter. Cross country skiing has its enthusiasts, as the accumulation of snow offers fantastic opportunities for snowmobiling and tubing. Christmas is predominantly white in the interior, even though the sunshine lasts for a daily 4 hours. December is a time for bulky jackets and caps in Connecticut.