Due to the size of the country there are large climatic variations in the USA. From a polar climate in northern Alaska to a (sub) tropical climate in Florida and Hawaii. Rainfall is unevenly distributed. There are areas with more rainfall in the northwest and southeast, while the southwestern states have deserts.
The individual states pages include graphs of the local temperature, precipitation and sunshine hours.
The temperature in the USA is indicated in degrees Fahrenheit (° F).
Pleasant throughout the country except in Alaska. In early spring (March, April) it may be still cold in the northern states and in the mountains.
Pleasant in the northern coastal states and Alaska. In the interior and the south it can be very hot in the middle of the day – combined with high humidity in the states along the Gulf of Mexico.
Pleasant throughout the country. Risk of tornadoes in the southern states. Most rainfall in the northwest. In the northeast a chance of some beautiful “Indian Summer” days.
Temperatures of 15 degrees Celsius in the southern states. Cold in the north and the interior.
Delaware, New Jersey, East-Pennsylvania, New York and the New England region (Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, Delaware)
This region has a generally unstable, humid climate with moderate rainfall throughout the year. Because of the polar influence even in early spring it may be still cold. Although this is one of the U.S. regions with the least sunshine, sun shines more often than in northwest Europe – on average 4-5 hours in winter and 9-19 hours in summer.
Autumn lasts but a few weeks in this part of the U.S., but it is world famous. This so-called “Indian Summer” is created as in the autumn the cold polar air from Canada wants to expel the remaining hot air. The cold air comes to a standstill and a high pressure system develops. The first day of the “Indian Summer” is usually pretty cold, but the subsequent days are getting warmer – up to 25 ° C. The heated air stays on the surface and is covered with a layer of cold air. The first nights of frost are the signal for the trees to shut off the food supply to their leaves. This also stops the production of green chlorophyll pigment, and spectacular red, brown and yellow colors of the leaves occur.
Maryland, Virginia, North Carolina, South Carolina, Georgia
The (Mediterranean) climate in the eastern states is tempered by the influence of the Atlantic ocean. Most rainfall during the summer. In the South (South Carolina, Georgia) humidity may be high during the summer.
West-Pennsylvania, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, Nebraska, Iowa, Illinois, Ohio, Kansas, Missouri, Indiana, Kentucky
The northern states in the Midwest have a continental climate with hot, short summers and long, harsh winters. The southern part has a more moderate weather type with long summers and mild winters with rainfall. Open skies and abundant sunshine are typical for this region.
Washington, Oregon en West-Idaho
The climate in this region resembles that of northwest Europe. It is often cloudy and it is the least sunny region of the U.S.. There is more rain in the mountain areas (2500-3000 mm per year) than in the relatively dry valleys (about 300 mm per year). The sun shines 2-3 hours per day during the winter at 9-10 in summer in the coastal region. Under the influence of the stable temperature of the ocean, there are only slight differences between winter and summer temperature in the coastal districts.
California has a Mediterranean climate, but the through the vastness of this region there are also significant differences. The climate on the coastal areas is similar to the northwestern states. Further south and inland, temperatures are higher with drier summers. In Nevada the weather type looks more and more like in the desert areas of Arizona and Northern Mexico. California is one of the sunniest states in the country (12-14 hours of sunshine per day in summer). The frequently occurring sea-fog on the northern coast (San Francisco) makes it less sunnier and a bit cooler in the summer.
Mid – Rocky Mountains
Montana, Idaho, Wyoming, Nevada, Utah, Colorado, Arizona, New Mexico en West-Texas
In general, in the northern Rocky Mountain states (Idaho, Montana, Wyoming) there is more precipitation and it is colder. A large portion of the south (Arizona, New Mexico, Utah, Colorado) consists of desert-like area with less than 300 mm rainfall per year. This southern part is also the sunniest climate in the U.S. – with 12-14 hours of sunshine per day in summer in Phoenix and Las Vegas. The high temperatures, combined with low humidity feel pretty comfortable.
Oklahoma, Arkansas, Tennessee, Oost-Texas, Louisiana, Mississippi en Alabama
The climate in these states seems pretty much that in the Midwest. Due to its southern location and under the influence of warm air from the Atlantic Ocean and the Gulf of Mexico winters are warmer and shorter. Only in western Texas in winter it can be cold now and then. Almost everywhere in the east the annual rainfall is between 1000 and 1250 mm. Rainfall in the west between 350 and 500 mm. Throughout the region there is a sunny climate, especially in western Texas and Oklahoma (average 10-11 hours per day in summer). The summer heat is well tolerated, except along the Gulf of Mexico, where the combination of heat and humidity sometimes feels uncomfortable. In late summer tornadoes occur in the entire southern region.
The northern coast and the interior of Alaska have a semi-polar climate. There is always snow on the mountains. Rivers are frozen from September until May. Because days are longer in summer it can be surprisingly warm. On the southern Pacific coast there is a different climate. There is more rainfall and the weather is less predictable. The summer temperatures are slightly lower here than inland.
Hawaii has a tropical climate with a constant-northeastern wind. The relatively uniform temperatures (23 ° C on average at sea level) are tempered by the wind and the height. Rainfall occurs primarily on the windward side of the islands. The south coast is relatively dry while the north east coast receives the most rainfall. In drier areas, most precipitation falls between October and March. Sunshine varies from 7-10 hours per day in the capital city of Honolulu and 4-5 hours in the wetter areas.