Humid Continental Climate - Dfb/Dwb/Dsb: Warm Summer Subtype

Dfb/Dwb/Dsb: Warm Summer Subtype

The warm summer version of the humid continental climate covers a much larger area than the hot subtype. In North America, the climate zone covers from about 44°N to 50°N latitude mostly east of the 100th meridian. However, it can be found as far north as 54°N, and further west in the Canadian Prairie Provinces and below 40°N in the high Appalachians. It can also be found in the Cascade Mountains of Washington and southern British Columbia above about 3000 feet (914 meters). In Europe this subtype reaches its most northerly latitude at nearly 61° N. Areas featuring this subtype of the continental climate have an average temperature in the warmest month below 22°C. Summer high temperatures in this zone typically average between 21–28 °C (70–82 °F) during the daytime and the average temperatures in the coldest month are generally far below the −3 °C (27 °F) isotherm.

Such high-altitude locations as South Lake Tahoe, California and Aspen, Colorado in the western United States exhibit local Dfb climates. The south-central and southwestern Prairie Provinces also fits the Dfb criteria from a thermal profile, but because of semi-arid precipitation portions of it are grouped into the BSk category.

In Europe, it is also found in central Scandinavia. In eastern Central Europe (eastern Austria, eastern Germany, Poland, Czech Republic, Slovakia, Hungary, Ukraine, northern Romania) and in coastal areas of central Scandinavia is a warm summer subtype with less severe winters, more similar to the winters of the hot summer subtype found in eastern North America – the winters here are modified by the oceanic climate influence of western Europe.

The warm summer subtype is marked by mild summers, long cold winters and less precipitation than the hot summer subtype, however, short periods of extreme heat are not uncommon. Northern Japan has a similar climate.

Much of Mongolia and parts of southern Siberia have a thermal regime fitting this climate, but they have steppe- or desert-like precipitation, and so are not really considered to have a humid continental climate.

In the Southern Hemisphere it exists in well-defined areas only in the Southern Alps of New Zealand and perhaps as isolated microclimates of the southern Andes of Chile and Argentina.