Most Monthly Precipitation in Cornwall History

This is a list of the largest monthly precipitation totals ever recorded in Cornwall, Ontario history from 1867–2024.

What Was the Wettest Month in Cornwall History?

According to NOAA records, the most precipitation that Cornwall, Ontario has ever received in a single month is 22.1 cm which occurred in October 2005.

Cornwall Most Rain in One Month

Rank	Precipitation	Month
1	22.1 cm	October 2005
2	22.0 cm	October 2019
3	19.8 cm	September 2010
4	19.5 cm	October 2003
5	19.1 cm	August 1955
6	18.8 cm	January 1978
7	18.7 cm	September 1979
8	18.7 cm	July 1996
9	18.3 cm	June 1998
10	18.0 cm	September 1973
11	17.4 cm	August 1965
12	17.1 cm	May 2000
13	17.0 cm	December 1973
14	16.9 cm	July 2006
15	16.3 cm	September 1999
16	15.9 cm	April 2011
17	15.8 cm	January 1998
18	15.8 cm	April 1993
19	15.8 cm	July 2017
20	15.6 cm	April 2000