Most Monthly Precipitation in Waterloo History

This is a list of the largest monthly precipitation totals ever recorded in Waterloo, Iowa history from 1895–2024.

What Was the Wettest Month in Waterloo History?

According to NOAA records, the most precipitation that Waterloo, Iowa has ever received in a single month is 13.4 inches which occurred in September 2018.

Month to date though April 23, 2024: 1.5 inches

Waterloo Most Rain in One Month

Rank	Precipitation	Month
1	13.4 inches	September 2018
2	12.8 inches	July 1999
3	12.6 inches	July 1968
4	11.4 inches	September 1965
5	11.3 inches	July 1993
6	11.0 inches	July 2010
7	10.8 inches	May 2013
8	10.8 inches	April 2008
9	10.5 inches	August 1998
10	10.3 inches	August 2007
11	10.1 inches	June 1993
12	9.7 inches	August 1993
13	9.6 inches	June 2014
14	9.6 inches	July 1990
15	9.5 inches	June 2018
16	9.3 inches	June 2020
17	9.0 inches	June 2016
18	8.9 inches	July 1969
19	8.8 inches	June 2008
20	8.8 inches	June 1998