, Japan, has a humid continental climate (
Köppen Dfa). Using the
Köppen climate classification, a climate is classified as humid continental when the temperature of the coldest month is below or and there must be at least four months whose mean temperatures are at or above . Wide temperature ranges are common within this climate zone. Second letter in the classification symbol defines seasonal rainfall as follows: •
s: A dry summer—the driest month in the high-sun half of the year (April to September in the Northern Hemisphere, October to March in the Southern Hemisphere) has less than / of rainfall and has exactly or less than the precipitation of the wettest month in the low-sun half of the year (October to March in the Northern Hemisphere, April to September in the Southern Hemisphere). •
w: A dry winter—the driest month in the low-sun half of the year has exactly or less than one‑tenth of the precipitation found in the wettest month in the summer half of the year. •
f: No dry season—does not meet either of the alternative specifications above; precipitation and humidity are often high year-round. while the third letter denotes the extent of summer heat:
Precipitation is relatively well distributed year-round in many areas with this climate (
f), while others may see a marked reduction in wintry precipitation,
Snowfall occurs in all areas with a humid continental climate and in many such places is more common than
rain during the height of winter. In places with sufficient wintertime precipitation, the snow cover is often deep. Most summer rainfall occurs during
thunderstorms, Within wetter areas,
maple,
spruce,
pine,
fir, and
oak can be found. Fall foliage is noted during the autumn of deciduous forests.
Neighboring climates In the poleward direction, these climates transition into
subarctic climates featuring short summers (and usually very cold winters) allowing only
conifer trees. Moving equatorword, the hot-summer continental climates grade into
humid subtropical climates (chiefly in North America and Asia) while the warm-summer continental climates grade into
oceanic climates (chiefly in Europe), both of which have milder winters where average temperatures stay above 0 °C (or -3 °C). Some continental climates with lower precipitation (chiefly in Central Asia and the Western United States) grade into
semi-arid climates with similar temperatures but low precipitation. == Hot summer subtype ==