If you planning to travel to Ameristar Casino St. Charles, St. Charles, Missouri, 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 12:01 PM. The temperature feels like 70.35 with a humidity level of 63 so dress accordingly. Cloud coverage is 6 percent with visibility at 14.2 percent. Today’s UV index is 6, don’t forget the sunscreen if you need it! Today’s winds are traveling southeast at a speed of 4 MPH. At the end of the day don’t miss the sunset at 11:37 PM.