They occur in both tropical and middle latitudes. They cover broad east-west bands near 30 degrees north and south latitude. Middle latitude semiarid and desert climates are in the rain shadows of mountain ranges. Winds that descend the leeward slopes of these ranges are warm and dry. Middle latitude semiarid areas and deserts differ from their tropical counterparts mainly in their seasonal temperature changes.
Winters are much colder in middle latitude semiarid areas and deserts.
Subtropical dry summer climates feature warm to hot, dry summers and mild, rainy winters. These climates, sometimes called Mediterranean climates, occur on the west side of continents roughly between 30 degrees and 45 degrees latitude. The closer to the coast the area is, the more moderate the temperatures and the less the contrast between summer and winter temperatures. Humid subtropical climates are characterized by warm to hot summers and cool winters. Rainfall is distributed fairly evenly throughout the year.