The United States experiences a wide range of weather patterns because of its continental scale, varied topography, and multiple coastlines. Conditions differ dramatically by region and season.
| Climate Aspect | Summary | |---|---| | Köppen climate classification | Multiple classifications nationwide, including humid subtropical, humid continental, Mediterranean, semi-arid, desert, marine west coast, subarctic, tundra, and tropical | | Average temperatures | Vary widely: subtropical warmth in the South and Hawaii, cold continental winters in the North and interior, severe Arctic cold in parts of Alaska, mild coastal conditions in parts of California and the Pacific Northwest | | Rainfall | Heavy in parts of the Southeast, Gulf Coast, Hawaii, and Pacific Northwest; lower in the interior West and desert Southwest | | Snowfall | Common to heavy across much of the North, Rockies, Great Lakes, Alaska, and higher elevations; limited or rare in much of the Deep South and Hawaii | | Humidity | Often high in the East, Southeast, and Gulf Coast; lower in many western interior regions | | Best time to visit | Depends on region and purpose: spring and autumn are often most comfortable in many populated areas |
Seasonal extremes are a regular part of life in many regions. Tornadoes are most associated with the Great Plains, Midwest, and South. Hurricanes affect the Atlantic and Gulf coasts. Wildfires are a recurring risk in the West, especially during dry and windy conditions. Flooding, drought, blizzards, heat waves, cold waves, and severe thunderstorms also occur across different regions.
Because the country spans tropical, temperate, desert, alpine, and Arctic environments, no single national average fully represents U.S. weather. Travelers and researchers usually rely on state- or city-level climate data for practical planning.