The average temperature in Great Falls, MT the average temperature is 34.22 degrees in summer, with precipitation around 6.0 mm , Shannon's temperatures reach 24.37 during the hot season, with 3.0 average of rain rate . In winter, however, weather indicators show around -1.92 degrees in Shannon, compared to the -22.4 average degrees reported in Great Falls, MT. During the winter period, Great Falls, MT can register 8.3 mm precipitation, while Shannon have an average of 3.0 mm rain level.