U.S. Climate Zones Map

Discover the diverse climate zones of the United States using the Köppen climate classification system. From the arctic tundra of Alaska to the tropical warmth of Hawaii and southern Florida, explore how temperature, precipitation, and seasonal patterns create distinct climate regions across America.

Major U.S. Climate Zones

Humid Subtropical

Cfa

Hot, humid summers and mild to cool winters with year-round precipitation.

  • States: Southeast U.S. (Georgia, Alabama, Mississippi, Louisiana, South Carolina, North Carolina, Virginia, Arkansas, Tennessee)
  • Average Temperature: 50-70°F (10-21°C)
  • Precipitation: 40-60 inches/year
  • Characteristics: Heavy summer thunderstorms, occasional winter snow in northern areas

Humid Continental

Dfa/Dfb

Large temperature differences between summer and winter, four distinct seasons.

  • States: Northeast and Midwest (New York, Pennsylvania, Ohio, Michigan, Wisconsin, Minnesota, Illinois, Indiana)
  • Average Temperature: 40-55°F (4-13°C)
  • Precipitation: 30-40 inches/year
  • Characteristics: Warm summers, cold snowy winters, colorful fall foliage

Semiarid/Steppe

BSk

Moderate precipitation, grassland climate with hot summers and cold winters.

  • States: Great Plains (Montana, Wyoming, Colorado, Kansas, Oklahoma, parts of Texas, New Mexico)
  • Average Temperature: 45-60°F (7-16°C)
  • Precipitation: 10-20 inches/year
  • Characteristics: Short grass prairies, occasional droughts, strong winds

Arid/Desert

BWk/BWh

Very low precipitation, extreme temperature variations between day and night.

  • States: Southwest (Nevada, Arizona, parts of California, Utah, New Mexico)
  • Average Temperature: 55-75°F (13-24°C)
  • Precipitation: Less than 10 inches/year
  • Characteristics: Sparse vegetation, dramatic landscapes, intense sunshine

Mediterranean

Csa/Csb

Dry summers and mild, wet winters characteristic of California coast.

  • States: California coast, parts of Oregon
  • Average Temperature: 55-65°F (13-18°C)
  • Precipitation: 15-30 inches/year (mostly winter)
  • Characteristics: Long dry summers, ideal for agriculture, wildfire season

Oceanic/Marine

Cfb

Mild temperatures year-round with frequent cloud cover and precipitation.

  • States: Pacific Northwest (Washington, Oregon coast)
  • Average Temperature: 50-60°F (10-15°C)
  • Precipitation: 40-100+ inches/year
  • Characteristics: Overcast skies, lush vegetation, temperate rainforests

Subarctic

Dfc/Dsc

Very cold winters, short cool summers, limited precipitation.

  • States: Alaska interior, northern Minnesota
  • Average Temperature: 20-35°F (-7 to 2°C)
  • Precipitation: 10-20 inches/year
  • Characteristics: Long, harsh winters, permafrost in some areas, taiga forests

Tundra

ET

Extremely cold year-round, no true summer, permanently frozen subsoil.

  • States: Northern Alaska, Alaska coastal areas
  • Average Temperature: Below 32°F (0°C) most of year
  • Precipitation: Less than 10 inches/year
  • Characteristics: Permafrost, treeless landscape, brief growing season

Tropical

Af/Am

Warm temperatures year-round with significant rainfall.

  • States: Hawaii, southern tip of Florida
  • Average Temperature: 70-80°F (21-27°C)
  • Precipitation: 60-200+ inches/year
  • Characteristics: No winter season, lush rainforests, high humidity

Understanding Köppen Climate Classification

The Köppen climate classification system, developed by climatologist Wladimir Köppen in 1900, is the most widely used system for classifying the world's climates. It categorizes climates based on average monthly temperature and precipitation patterns.

Climate Classification System

The system uses a letter code system:

Code Climate Type Description
A Tropical Average temperature of coldest month above 64°F (18°C)
B Arid Evaporation exceeds precipitation
C Temperate Coldest month between 27-64°F (-3 to 18°C)
D Continental Coldest month below 27°F (-3°C), warmest above 50°F (10°C)
E Polar Warmest month below 50°F (10°C)

Precipitation Patterns (Second Letter)

Temperature Patterns (Third Letter)

Example: "Cfa" means temperate climate (C) with precipitation year-round (f) and hot summers (a). This describes much of the southeastern United States.

Climate Zones by State

States with Multiple Climate Zones

Many large states span multiple climate zones due to variations in elevation, latitude, and proximity to water bodies:

California - The most climatically diverse state:

Texas - Climate varies dramatically across the state:

Alaska - Extreme climate diversity:

States with Uniform Climate

Some smaller states have relatively uniform climate zones:

Climate Change and Shifting Zones

Climate zones are not static. Scientific evidence shows that climate zones in the United States are shifting due to global climate change.

Observed Changes

Regional Impacts

Southwest:

Southeast:

Northeast:

Alaska:

Impact on Agriculture: Shifting climate zones affect what crops can be grown where. Farmers are adapting by planting different varieties or crops that were previously only viable further south.

Microclimates and Local Variations

While broad climate zones provide a general framework, local geography creates microclimates that can differ significantly from the surrounding region.

Factors Creating Microclimates

Elevation:

Urban Heat Islands:

Water Bodies:

Rain Shadows:

Notable Microclimates

San Francisco Bay Area: Contains numerous microclimates within a small region, from foggy coast to warm inland valleys, often varying dramatically within just a few miles.

Puget Sound: Protected waterways create milder, drier conditions than the surrounding Pacific Northwest rainforest climate.

Willamette Valley, Oregon: Rain shadow effect from Coast Range creates drier, warmer conditions ideal for wine production.

Climate and Human Activity

Population Distribution

Climate zones significantly influence where Americans choose to live:

Economic Activities

Climate zones dictate agricultural possibilities and economic development:

Agriculture:

Energy Use:

Tourism and Recreation

Climate zones create diverse tourism opportunities:

Frequently Asked Questions

What U.S. state has the most diverse climate?

California has the most diverse climate, featuring Mediterranean, desert, semiarid, oceanic, and highland climates all within one state. This diversity is due to its large size, varied topography, and range of latitudes and elevations.

Which climate zone covers the largest area in the U.S.?

The semiarid/steppe climate (BSk) covers the largest continuous area, spanning much of the Great Plains and interior West. However, if we include subarctic climates in Alaska, that would be the most extensive single climate type by total area.

Why doesn't the entire West Coast have the same climate?

The West Coast climate varies dramatically due to latitude, ocean currents, and topography. The Pacific Northwest has an oceanic climate with heavy rainfall, California has a Mediterranean climate with dry summers, and Southern California transitions to semiarid and desert climates. The California Current brings cool water to the coast, while mountain ranges create rain shadows inland.

How does climate affect where people live in the U.S.?

Climate is a major factor in population distribution. Most Americans live in temperate climates (humid subtropical and humid continental zones). Extreme climates like arctic tundra, hot deserts, and subarctic regions have much lower population densities. However, technology like air conditioning has enabled population growth in previously challenging climates like the desert Southwest.

Are U.S. climate zones changing?

Yes, climate zones are shifting due to global climate change. Many areas are experiencing warmer temperatures, altered precipitation patterns, and earlier springs. USDA plant hardiness zones have shifted northward, and some regions are transitioning between climate classifications. These changes affect agriculture, ecosystems, and human activities.