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 12:10 PM. The temperature feels like 50.550000000000004 with a humidity level of 41 so dress accordingly. Cloud coverage is 7 percent with visibility at 14.9 percent. Today’s UV index is 8, don’t forget the sunscreen if you need it! Today’s winds are traveling east at a speed of 4 MPH. At the end of the day don’t miss the sunset at 2:59 AM.