Temperatures in the United States vary widely due to its large size and diverse topography. In fact, the country is home to some of the hottest places on earth, as well as its coldest. Parts of Alaska have an average monthly temperature below -10°F (-23°C) during the coldest months, while Death Valley averages over 115°F (46°C) in the summer. Of course, different parts of the country experience temperatures everywhere between these two extremes.
There are seven major climate zones in the United States. Generally, overall temperatures are warmer as one travels further south, while the air becomes drier as one moves further west until hitting the west coast. The Southwest region of the U.S. has many vast deserts and tends to have a hot, arid climate. The country's Southeast region has a sub-tropical climate characterized by hot, humid summers and mild winters. The Northwest fluctuates between bitterly cold winters and somewhat hot, humid summers. The West Coast experiences cool, wet winters and dry, warm summers. The Midwest has humid summers and harsh winters, especially in the northern states.
According to the National Oceanic and Atmospheric Administration, the United States experienced its fifth-hottest year on record in 2021, despite an arctic blast that plunged much of the south into abnormal freezing temperatures in February. The nation's average daytime highs reached 66.4°F (19.1°C), while average nighttime lows for the country were 42.6°F (5.9°C).
The Coldest States in the U.S.
Alaska
Alaska is the coldest state in the U.S. Alaska's average temperature is 28.1°F (-2.7°C) and can go as low as -30°F (-34°C) during the winter months. The Fairbanks area experiences some of the hottest and coldest temperatures in the state, with highs of 90°F in the summer and lows around -50°F.
North Dakota
North Dakota is the nation's second-coldest state, with an average temperature of 41.1°F (5°C). The eastern half of North Dakota experiences a humid continental climate, and the western half experiences a semi-arid climate. In the winter, the average temperatures are around 24°F (-4.4°C), perfect for winter activities such as snowmobiling, cross country skiing, ice skating, and ice hockey. The coldest month in North Dakota is January, where temperatures range from 2°F (-16.7°C) in the north and 17°F (-8.3°C) in the south.
Minnesota
Minnesota is the third-coldest state in the U.S. Minnesota's humid continental climate is greatly influenced by its proximity to Canada to its north and Lake Superior to its northeast. January is the coldest month in Minnesota, where temperatures as low as -30°F (-34°C) can be found around the state's northern parts. The average temperature overall in Minnesota is 41.8°F (5.4°C).
Maine
Maine has an average annual temperature of 41°F (5°C), making it the fourth-coldest state. The state has a humid continental climate, as are most New England states, characterized by large seasonal contrasts with hot summers and cold winters. Winters in Maine have an average low temperature of 12°F (-11°C) and abundant snowfall. The average accumulated snowfall in Maine is 10 to 80 inches (25-203 cm). Caribou, the northeastern-most city in the U.S., saw 157 consecutive days with at least one inch of snow on the ground in 2018.
Wyoming
Wyoming is the fifth-coldest state in the United States, with an average temperature of 42.3°F (5.7°C). The average minimum temperature in the winter range from 0°F to 15°F. During winter, the state's highlands and mountaintops can experience up to 200 inches of snowfall, and lowlands typically accumulate about 50 inches of snow. Winds are typically in the range of 30 to 40 mph (48-64 kph), with gusts up to 50 to 60 mph.
Hottest States in the U.S.
Florida
Florida is the hottest state in the U.S., with an average annual temperature of 71.5°F (21.9°C) between 1991 and 2020. It is the southernmost contiguous U.S. state with a subtropical climate in its northern and central regions and a tropical climate in its southern regions. Winters are mild, and summers are hot and humid. July is the hottest month in Florida, averaging 90°F to 92°F and frequently hitting or going above 100°F.
Hawaii
Hawaii is the second-hottest state in the U.S., with an average annual temperature of 70.2°F. The weather in Hawaii is very consistent, with little variation in average daily temperatures. The state has never reached temperatures below freezing (32ºF / 0°C) or above 100°F (37.7°C). Hawaii has the largest number of climate zones of any state, with 11 different zones across its many islands, including sea-level, arid, semi-arid, temperate, and alpine.
Louisiana
With an average annual temperature of 66.4°F, Louisiana is the third-hottest state in the United States. Louisiana has a subtropical climate with long, hot, and humid summers and short, mild winters. August is Louisiana's hottest month, where average highs range from 89°F to 94°F. Louisiana's position on the Gulf of Mexico gives it a considerable wet season and high humidity, making the heat feel like 120°F.
Texas
With an average annual temperature of 65.3°F, Texas is the fourth-hottest state. Texas has arid and semi-arid climates in its west and humid and sub-tropical climates in its east. August is Texas's hottest month, with average high temperatures in the 93°F to 101°F range. In January, Texas's coldest month, the average high temperatures are between 52°F and 71°F.
Georgia
Georgia is the fifth-hottest U.S. state. Like its neighbor Florida, the state has a subtropical climate. The average annual temperature is 64.3°F (17.9°C). The southern region of the state has summers ranging from 90°F to 100°F, while the northern part has milder summers ranging from 72°F to 82°F.