Weather By Day

May Weather In Helena  
May Helena Weather
Record High: 95°F
Normal High: 66°F
Normal Low: 40°F
Record Low: 17°F
Avg Monthly Rain: 1.78"
Rec 1 Day Rain: 2.06"
Avg Monthly Snow: 1.4"
Rec 1 Day Snow: 12.5"

Helena Weather In May

The hottest day in Helena Montana in May for the past 70 years was 95 degrees Fahrenheit, most recently encountered on May 28, 1919, and the standard high is 66. The lowest documented temperature in May for Helena for the past 70 years was 17 on May 1, 1954, while the regular low temperature for a given day during the month is 40.

According to National Weather Service Helena May Weather data, on May 2, 1899, the recorded high temperature did not exceed 31 degrees Fahrenheit, the lowest high measured in Helena in the past 70 years. Weather Service data also shows that on May 31, 1936, the lowest recorded temperature for the day did not drop below 65 degrees, the highest low measured temperature in Helena in the last 70 years.

According to the National Weather Service, the high temperature in Helena in May on the first day of the month averages 59 degrees and the high on the last day of the month averages 67 degrees. The low measured temperature in Helena on May First averages 36 degrees and the low on the last day of the month averages 44 degrees.

Helena usually receives an average of 1.78 inches of precipitation during the month. The most rain recorded in a single day, as shown by May Helena Weather data, was 2.06 inches on May 3, 1964. Helena receives an average of 1.4 inches of snow in May. The highest snowfall measured in a single day in May was 12.5 inches on May 10, 1967.