If you planning to travel to Big Arm State Park, Big Arm, Montana, 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 3:24 PM. The temperature feels like 35.6 with a humidity level of 83 so dress accordingly. Cloud coverage is 84 percent with visibility at 13.2 percent. Today’s UV index is 0, don’t forget the sunscreen if you need it! Today’s winds are traveling southwest at a speed of 3 MPH. At the end of the day don’t miss the sunset at 11:48 PM.