In the summer, when the land heats faster than the ocean, low pressure forms over Asia and warm, moist south to southeasterly winds bring heavy, thundery rain, yielding annual rainfall ranging from , or less in the west, to over in the Changbai Mountains. Temperatures in the summer are very warm to hot, with July average maxima ranging from in the south to in the extreme north. Except in the far north near the Amur River, high humidity causes major discomfort at this time of year.