Most Monthly Precipitation in Helena History

This is a list of the largest monthly precipitation totals ever recorded in Helena, Montana history from 1893–2024.

What Was the Wettest Month in Helena History?

According to NOAA records, the most precipitation that Helena, Montana has ever received in a single month is 6.7 inches which occurred in May 1927.

Helena Most Rain in One Month

Rank	Precipitation	Month
1	6.7 inches	May 1927
2	6.2 inches	May 1908
3	6.1 inches	May 1981
4	5.3 inches	June 1915
5	4.9 inches	May 1898
6	4.8 inches	June 1908
7	4.7 inches	June 1944
8	4.7 inches	July 1993
9	4.6 inches	June 2005
10	4.4 inches	June 2002
11	4.3 inches	June 1947
12	4.3 inches	May 1980
13	4.3 inches	June 1909
14	4.3 inches	June 1958
15	4.2 inches	August 1974
16	4.2 inches	June 1907
17	4.1 inches	May 1901
18	4.1 inches	June 2011
19	4.0 inches	May 1912
20	3.9 inches	July 1975