Most of its area is an inhospitable semi-desert known as the Kalahari. Even the most arable sections of eastern Botswana are subject to periodic drought and unpredictable rains. Botswana straddles the Tropic of Capricorn and has an average elevation of 3,300 feet. Daily high temperatures during the hottest month, January, average in the upper 90's to over 100°F. Winter daytime temperatures generally reach 70 degrees, but with little cloud cover and no humidity to hold warmth in the air, they plummet to 30 or 40°F at night.