Most Monthly Precipitation in St. Helena History

This is a list of the largest monthly precipitation totals ever recorded in St. Helena, California history from 1907–2023.

What Was the Wettest Month in St. Helena History?

According to NOAA records, the most precipitation that St. Helena, California has ever received in a single month is 27.6 inches which occurred in January 1909.

St. Helena Most Rain in One Month

Rank	Precipitation	Month
1	27.6 inches	January 1909
2	25.6 inches	February 1986
3	24.3 inches	December 1955
4	23.3 inches	January 1995
5	22.5 inches	January 1916
6	22.1 inches	December 2002
7	20.6 inches	December 2005
8	19.8 inches	January 1970
9	19.6 inches	December 1913
10	19.0 inches	January 1914
11	17.7 inches	January 2017
12	17.3 inches	January 1973
13	17.2 inches	February 1915
14	17.1 inches	January 1969
15	17.1 inches	December 2014
16	17.0 inches	February 1998
17	17.0 inches	December 1940
18	17.0 inches	February 1983
19	16.9 inches	January 1967
20	16.8 inches	March 1995