South Dakota consists of three major regions; the Prairie, the Great Plains, and the Black Hills.
Water
The Missouri is the chief river of South Dakota. Together with many tributaries, it drains virtually the entire state. The Missouri flows in a somewhat southeasterly course through the center of the state, then easterly along the Nebraska–South Dakota border. From the west, it receives the waters of five major tributaries: the Grand, Moreau, Cheyenne, Bad, and White rivers. Eastern South Dakota is drained primarily by the Big Sioux and James rivers, both of which are southerly flowing tributaries of the Missouri..
All of South Dakota's large lakes, Oahe, Sharpe, Francis Case, and Lewis and Clark, are reservoirs created by dams built on the Missouri River during the 1950's and 60's. Of the four, Oahe is by far the largest. Besides controlling floods, the dams provide hydroelectric power, water for irrigation, and numerous recreational facilities. Small glacially created lakes dot parts of eastern South Dakota, particularly the Prairie Coteau. There are also artesian sources of water in the east and hot springs in the Black Hills.
Climate
Because of its central location in North America, far from any tempering influence of the ocean, South Dakota has a continental climate marked by great extremes in the weather. Winters are long and cold, with frequent readings below 0 F. January is the coldest month, averaging between 10° and 20° F. throughout most of the state. Summer daytime temperatures often rise to 100° F. The hottest month, July, averages 72° to 75° F , with the Black Hills somewhat cooler. Except for the Black Hills and the extreme southeastern corner of the state, which receive about 25 inches of moisture each year, South Dakota gets meager amounts of precipitation. It decreases from about 20 inches annually in the east to about 13 inches in the northwest, where semiarid conditions prevail. The total amount is highly variable from year to year, and serious droughts periodically occur. Normally, most of the precipitation comes as rain from April to September, which corresponds roughly to the crop growing season. Snows are usually light, but tend to accumulate to considerable depths during the long, cold winter. Blizzards occasionally occur.
Water
The Missouri is the chief river of South Dakota. Together with many tributaries, it drains virtually the entire state. The Missouri flows in a somewhat southeasterly course through the center of the state, then easterly along the Nebraska–South Dakota border. From the west, it receives the waters of five major tributaries: the Grand, Moreau, Cheyenne, Bad, and White rivers. Eastern South Dakota is drained primarily by the Big Sioux and James rivers, both of which are southerly flowing tributaries of the Missouri..
All of South Dakota's large lakes, Oahe, Sharpe, Francis Case, and Lewis and Clark, are reservoirs created by dams built on the Missouri River during the 1950's and 60's. Of the four, Oahe is by far the largest. Besides controlling floods, the dams provide hydroelectric power, water for irrigation, and numerous recreational facilities. Small glacially created lakes dot parts of eastern South Dakota, particularly the Prairie Coteau. There are also artesian sources of water in the east and hot springs in the Black Hills.
Climate
Because of its central location in North America, far from any tempering influence of the ocean, South Dakota has a continental climate marked by great extremes in the weather. Winters are long and cold, with frequent readings below 0 F. January is the coldest month, averaging between 10° and 20° F. throughout most of the state. Summer daytime temperatures often rise to 100° F. The hottest month, July, averages 72° to 75° F , with the Black Hills somewhat cooler. Except for the Black Hills and the extreme southeastern corner of the state, which receive about 25 inches of moisture each year, South Dakota gets meager amounts of precipitation. It decreases from about 20 inches annually in the east to about 13 inches in the northwest, where semiarid conditions prevail. The total amount is highly variable from year to year, and serious droughts periodically occur. Normally, most of the precipitation comes as rain from April to September, which corresponds roughly to the crop growing season. Snows are usually light, but tend to accumulate to considerable depths during the long, cold winter. Blizzards occasionally occur.