 This forecast is brought to you by Montana Internet Fiber, voted best Internet provider in Helena and the official Internet service provider of the Montana Radio Company. Visit mt.net. Tonight, partly cloudy skies with low temperatures down to around 55. Sunday, increasing clouds, potential for a shower or thundershower as the afternoon progresses. High temperatures will be up into the upper 70s. Sunday night, risk for an evening shower or thundershower, then clearing. Lows near 55.