Located in the Big Sioux River Valley in southeast South Dakota, Sioux Falls is surrounded by gently rolling terrain that slopes to higher elevations approximately 100 miles to the north-northeast and to the south. The city's climate is continental, exhibiting frequent weather changes from day to day and from week to week as differing air masses move into the area. During the late fall and winter, strong winds cause abrupt drops in temperature, but cold spells are usually of short duration. Snowfall and sleet average 38.1 inches yearly, and one or two heavy snows fall each winter, with blizzard conditions sometimes resulting. Thunderstorms are common in late spring and summer; tornadoes can occur from spring through summer. Flooding from melting snow runoff in the spring along the Big Sioux River and Skunk Creek is reduced by a diversion canal around the city.
Area: 56.34 square miles (2000)
Elevation: 1,421 feet above sea level
Average Temperatures: January, 14.0° F; July, 73.0° F; annual average, 45.1° F
Average Annual Precipitation: 24.69 inches of rain, 38.1 inches of snow