Temperature for May
In Great Falls, MT during May the average high temperature is 67.0°F. The hottest day on record was May 22, 1980 when the temperature hit 92.8°F.
Precipitation for May
In May the average monthly rainfall in Great Falls, MT is 2.38 inches with rain usually falling on between 11 and 12 days. 1996 was the driest May with only 0.41 inches of rain falling, and 1980 was the wettest May with 5.72 inches of rain. The wettest single day in May was 26 May 1980 when 2.60 inches of rain fell.
In May it usually snows on between 2 and 3 days. There are thunderstorms on between 2 and 3 days in May.