Humi Subtropical climate (Köppen Cfa or Cwa) is a climate zone characterized by hot, humid summers and chilly to mild winters. This climate type covers a broad category of climates, and the term "subtropical" may be a misnomer for the winter climate in the cooler areas within this category. Significant amounts of precipitation occur in all seasons in most areas. Winter rainfall (and sometimes snowfall) is associated with large storms that the westerlies steer from west to east. Most summer rainfall occurs during thunderstorms and an occasional tropical storm, hurricane or cyclone.