Traveling to Horse Thief Lake, Keystone, South Dakota? Here is your 6-day weather forecast in the area. Whether it is a warm weather destinations or cold climate don’t forget to consider weather, while you pack your bags for this trip. Start your day when the sunrises at 2:00 PM and don’t miss the sunset at 11:19 PM. Today’s winds are traveling west-southwest at a speed of 5 MPH. The temperature feels like 30 with a humidity level of 62. Cloud coverage is 73 percent with 9.9 percent visibility. Today’s UV index is 1 make sure to prepare properly. Make sure to plan your travel itinerary to match your travel weather forecast to make the most of your vacation with Reservations.com.