Earliest and Latest Days of 20° C in Cornwall

This is a list of the earliest and latest days in the year with a high temperature of at least 20 °C in Cornwall, Ontario history. It is based on NOAA data from the years 1867–2024.

Also see:

Earliest 20 degree day in Cornwall?

The earliest in the year that Cornwall, Ontario had a high temperature of at least 20 °C is February 27 which happened in 2024.

Latest 20 degree day in Cornwall?

The latest in the year that Cornwall, Ontario had a high temperature of at least 20 °C is December 5 which happened in 2001.

Earliest Days ≥ 20 °C

Date	Year	Temperature
February 27	2024	21.0 °C
March 9	2002	20.0 °C
March 9	2000	21.0 °C
March 17	1868	20.0 °C
March 18	2012	24.0 °C
March 19	2012	24.0 °C
March 20	2012	25.0 °C
March 21	2012	26.0 °C
March 22	2021	21.0 °C
March 22	2012	25.0 °C
March 23	2021	21.0 °C
March 23	1979	21.5 °C
March 25	2021	20.0 °C
March 25	1996	21.0 °C
March 25	1988	20.0 °C
March 26	2004	20.0 °C
March 26	1986	22.0 °C
March 27	1976	21.7 °C
March 28	1998	21.0 °C
March 29	1977	20.0 °C
March 29	1962	20.0 °C

Latest Days ≥ 20 °C

Date	Year	Temperature
December 5	2001	20.0 °C
November 29	2005	20.5 °C
November 28	1990	22.5 °C
November 24	2014	21.0 °C
November 24	2003	20.5 °C
November 22	1953	21.1 °C
November 22	1883	20.0 °C
November 20	1991	20.0 °C
November 20	1985	20.0 °C
November 16	1989	20.0 °C
November 14	1994	20.0 °C
November 14	1959	20.6 °C
November 12	2012	23.0 °C
November 12	1982	20.5 °C
November 11	2020	20.0 °C
November 11	2002	21.5 °C
November 10	2020	24.0 °C
November 10	2002	21.5 °C
November 10	1966	20.6 °C
November 9	2020	22.0 °C
November 9	2009	20.5 °C
November 9	1879	20.6 °C