The climate for most of the state is generally semi-arid. In the summer it can be very hot in southern New Mexico. The temperature is sometimes over 100 °F (37.8 °C) with lows over 70 °F (21.1 °C). It occasionally snows in the northern part of the state in the winter. It is drier in the southern portion of the state, and it rarely snows. New Mexico is usually affected by the North American monsoon from mid June to late September.