June has pleasant summer temperatures in South Dakota that see tourists in droves visit its parks, wildlife, and American Indian historical monuments. Average high temperatures are in a temperate 60°F (15.6°C) to 70°F (21.1°C) range, while average low temperatures are comfortable between 50°F (10°C) to 60°F (15.6°C). June is rainy as most of the state register 4" (102mm) - it is moderately humid, and daylight lasts almost 15 hours with an average of 20 sunny days. Yankton in the east has average temperatures in the 57°F (13.9°C) to 82°F (27.8°C), while Mount Rushmore in the west is between 51°F (10.6°C) to 71°F (21.7°C) - no wonder it is full of enthusiastic visitors. South Dakota summers are vulnerable to thunderstorms and tornadoes - keep in mind that the southeastern part of the state lies in the Tornado Alley of the country. The weather is beautiful and suitable for swimming in the rivers and lakes. People enjoy sunbathing, particularly in the sunny days of early summer, when the sun rays have less intensity.