If you planning to travel to Rushmore Cave, Keystone, South Dakota, here is your 6-day travel weather forecast to make sure you have all the essentials needed during your stay. Start your day when the sunrises at 1:45 PM. The temperature feels like 45 with a humidity level of 50 so dress accordingly. Cloud coverage is 46 percent with visibility at 14.9 percent. Today’s UV index is 0, don’t forget the sunscreen if you need it! Today’s winds are traveling west-southwest at a speed of 14 MPH. At the end of the day don’t miss the sunset at 11:29 PM.