Earliest and Latest Days at or Below 0° C in Cornwall

This is a list of the earliest and latest days in a winter season where the low temperature fell to at least 0 °C in Cornwall, Ontario history. It is based on NOAA data from the years 1867–2024.

Earliest freezing temperature in Cornwall?

The earliest in a winter season that Cornwall, Ontario has recorded a low temperature of 0 °C or below is September 8 which happened in 1952.

Latest freezing temperature in Cornwall?

The latest in a winter season that Cornwall, Ontario has recorded a low temperature of 0 °C or below is May 30 which has happened twice, most recently in 1961.

Earliest Days ≤ 0 °C

Date	Year	Temperature
September 8	1952	-1.1 °C
September 9	1956	0.0 °C
September 11	1885	0.0 °C
September 11	1883	0.0 °C
September 14	1884	-1.7 °C
September 14	1871	0.0 °C
September 14	1867	0.0 °C
September 15	1953	0.0 °C
September 15	1873	-0.6 °C
September 16	1959	0.0 °C
September 16	1873	-0.6 °C
September 16	1867	-2.8 °C
September 17	1887	-0.6 °C
September 17	1873	-0.6 °C
September 18	1873	-1.7 °C
September 19	2014	-1.0 °C
September 21	2020	0.0 °C
September 21	1956	-0.6 °C
September 21	1871	-1.1 °C
September 22	2020	0.0 °C
September 22	1886	-0.6 °C
September 22	1873	-0.6 °C
September 22	1871	0.0 °C
September 22	1868	-1.1 °C

Latest Days ≤ 0 °C

Date	Year	Temperature
May 30	1961	-0.6 °C
May 30	1884	-1.1 °C
May 29	1884	-0.6 °C
May 27	1954	-1.7 °C
May 26	1969	0.0 °C
May 26	1956	-1.1 °C
May 26	1879	-0.6 °C
May 25	1956	-2.8 °C
May 24	1956	-4.4 °C
May 24	1879	0.0 °C
May 23	1870	-0.6 °C
May 21	1957	-1.1 °C
May 20	1956	-1.7 °C
May 20	1954	-1.1 °C
May 18	2023	0.0 °C
May 17	1983	0.0 °C
May 17	1981	0.0 °C
May 17	1957	-4.4 °C
May 17	1956	-2.8 °C
May 17	1955	-2.2 °C