Cornwall Average Rainfall by Month

This page shows the average precipitation (including snowfall) in each month of the year in Cornwall, Ontario. It is based on NOAA data for the years 1991–2020.

Average temperature by month

What's the Rainiest Month in Cornwall?

In Cornwall, October has the greatest precipitation of any month. On average, Cornwall gets 9.9 cm of precipitation in October.

However, January is the month with the greatest chance of precipitation. 44.9% of days in January will have at least some rain or snow.

What's the Driest Month in Cornwall?

In Cornwall, March has the least precipitation of any month. On average, Cornwall gets 6.30 cm of precipitation in March.

March is also the month where rain is least common. 34.4% of days in March will have measurable rain or snow.

Month	Precipitation	% Chance
January	7.78 cm	44.9
February	6.31 cm	40.6
March	6.30 cm	34.4
April	8.69 cm	40.2
May	8.54 cm	40.5
June	9.13 cm	41.8
July	9.68 cm	37.9
August	8.63 cm	34.9
September	9.40 cm	37.2
October	9.94 cm	41.2
November	7.69 cm	43.1
December	7.53 cm	45.8
Year	98.59 cm	39.9

Weather Station Details

Years	Station	Coordinates
1950–2024	Cornwall	location
1867–1887	Cornwall	location