This map displays the 22 Köppen climate regions that cover the United States and Puerto Rico. Click on the map to get more information about each unique region. The button in the lower right will display a map legend with the classifications. You can toggle US state boundaries using the layer control in the top right corner. Full descriptions of each region can be found in the table below the map.
Köppen categorizes climates into five major climate groups. These groups are based on seasonal rainfall and temperature patterns. The five major climate groups are: A (tropical), B (arid), C (temperate), D (continental), E (polar), All climate groups and subgroups are denoted by a letter, and all climates are assigned to a main climate group (letter A). All climate groups except E are assigned to seasonal precipitation subgroups (letter B).
Class A climates are characterized by constant high temperatures (at sea level and low elevations) with year round average temperatures of 18 °C (64.4 °F) or higher. In the United States, class A tropical climates are found in South Florida, Hawaii, Puerto Rico and the US Virgin Islands.
Year–round average precipitation of at least 60 mm (2.4 in). Usually occur within 5–10° latitude (North and South) of the equator. In some Eastern-coast areas, they may extend to as much as 25° away from the equator. This climate is dominated by the doldrums low-pressure system all year round, so has no natural seasons.
This type of climate (Am), most common in South America, results from the monsoon winds which change direction according to the seasons. This climate has a driest month (which nearly always occurs at or soon after the "winter" solstice for that side of the equator) with rainfall less than 60 mm, but more than 1/25 the total annual precipitation.
Class Aw climates have a pronounced dry season, with the driest month having precipitation less than 60 mm and less than 1/25 of the total annual precipitation.
Class B Climates are characterized by potential evaporation and transpiration exceeding precipitation. These climates are usually found in areas from 20 - 35° North and South of the equator and in large continental regions of the mid-latitudes often surrounded by mountains.
Hot desert climates usually feature hot, sometimes exceptionally hot, periods of the year. In many locations featuring a hot desert climate, maximum temperatures of over 40 °C (104 °F) are not uncommon in summer and can soar to over 45 °C (113 °F) in the hottest regions.
Cold desert climates (BWk) sometimes feature hot and dry summers, though summers typically are not quite as hot as summers in hot desert climates. Unlike hot desert climates, cold desert climates sometimes feature cold winters with marginal snow. Cold desert climates are typically found at higher altitudes than hot desert climates, and are usually drier than hot desert climates.
At least one month's averages below 0 °C (32 °F).
Class C climates have an average monthly high temperature of 10 °C (50 °F) or more in the spring/summer months (April to September in northern hemisphere), and an average monthly low temperature greater than −3 °C (27 °F) in the fall/winter months.
Csa Mediterranean Climates mostly occur on the western sides of continents between the latitudes of 30° and 45°. These climates are in the polar front region in winter, and thus have moderate temperatures and changeable, rainy weather. Summers are hot and dry, due to the domination of the subtropical high pressure systems, except in the immediate coastal areas, where summers are milder due to the nearby presence of cold ocean currents that may bring fog but prevent rain.
Coldest month averaging above 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and driest month of summer receives less than 30 mm (1.2 in).
Hot Summer Temperatures Greater than or equal to 22 °C
Coldest month averaging above 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F).
Cold subtropical highland climate or subpolar oceanic climate with dry winters. Coldest month averaging above 0 °C (32 °F) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
Coldest month averaging above 0 °C (32 °F) and at least one month's average temperature above 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
coldest month averaging above 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
Cold subtropical highland climate or subpolar oceanic climate with dry winters. Coldest month averaging above 0 °C (32 °F) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
These climates have an average temperature above 10 °C (50 °F) in their warmest months, and a coldest month average below −3 °C (or 0 °C in some versions, as noted previously). These usually occur in the interiors of continents and on their upper east coasts, normally north of 40°N. In the Southern Hemisphere, group D climates are extremely rare due to the smaller land masses in the middle latitudes and the almost complete absence of land at 40–60°S, existing only in some highland locations.
Coldest month averaging below 0 °C (32 °F) and at least one month's average temperature above 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and driest month of summer receives less than 30 mm (1.2 in).
Coldest month averaging below 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and driest month of summer receives less than 30 mm (1.2 in).
Coldest month averaging below 0 °C (32 °F) and 1–3 months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and driest month of summer receives less than 30 mm (1.2 in).
Coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). At least three times as much precipitation in the wettest month of winter as in the driest month of summer, and driest month of summer receives less than 30 mm (1.2 in).
Coldest month averaging below 0 °C (32 °F) and at least one month's average temperature above 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
coldest month averaging below 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
coldest month averaging below 0 °C (32 °F) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (alternative definition is 70% or more of average annual precipitation is received in the warmest six months).
coldest month averaging below 0 °C (32 °F) and at least one month's average temperature above 22 °C (71.6 °F) and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
coldest month averaging below 0 °C (32 °F), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
coldest month averaging below 0 °C (32 °F) and 1–3 months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
coldest month averaging below −38 °C (−36.4 °F) and 1–3 months averaging above 10 °C (50 °F). No significant precipitation difference between seasons (neither abovementioned set of conditions fulfilled).
These climates are characterized by average temperatures below 10 °C in all 12 months of the year. These climates only occur in the United States along the North coast of Alaska.
Warmest month has an average temperature between 0 and 10 °C. These climates occur on the northern edges of the North American and Eurasian land masses, and on nearby islands. ET climates are also found on some islands near the Antarctic Convergence, and at high elevations outside the polar regions, above the tree line. In the United States the North coast of Alaska is mostly in the climate region.
This climate is dominant in Antarctica and inner Greenland, but also occurs at extremely high altitudes on mountains, above even tundra. All twelve months have average temperatures below 0 °C (32 °F).