SXUS45 KMSO 012330 RECGPI Recreation Forecast for Flathead Lake National Weather Service Missoula MT 505 PM MDT Tue Sep 1 2026 Note: The experimental wave height forecasts are representative of the mid lake waters and downwind shores. Wave heights may be significantly less on upwind shores. .Tonight...Mostly cloudy. A 20 percent chance of rain in the evening. Lows around 60 . Variable winds up to 10 mph. Waves less than 1 foot. .WEDNESDAY...Partly sunny with a slight chance of rain in the morning, then cloudy with showers and a chance of thunderstorms in the afternoon. Highs in the upper 60s. Variable winds up to 10 mph becoming southwest around 15 mph in the afternoon. Chance of precipitation 80 percent. Waves less than 1 foot. .WEDNESDAY NIGHT...Mostly cloudy with a 40 percent chance of rain. Lows in the lower 50s. South winds around 15 mph in the evening becoming light. Waves around 1 foot...locally up to 2 feet. .THURSDAY...Mostly cloudy. Rain likely in the morning, then a chance of rain in the afternoon. Highs around 60 . Variable winds up to 10 mph. Chance of rain 60 percent. Waves less than 1 foot.