Earliest and Latest Days of 20° C in Thunder Bay

This is a list of the earliest and latest days in the year with a high temperature of at least 20 °C in Thunder Bay, Ontario history. It is based on NOAA data from the years 1941–2024.

Also see:

Earliest 20 degree day in Thunder Bay?

The earliest in the year that Thunder Bay, Ontario had a high temperature of at least 20 °C is March 20 which happened in 2012.

Latest 20 degree day in Thunder Bay?

The latest in the year that Thunder Bay, Ontario had a high temperature of at least 20 °C is November 6 which happened in 2020.

Earliest Days ≥ 20 °C

Date	Year	Temperature
March 20	2012	21.1 °C
March 26	2007	20.4 °C
March 28	1946	22.8 °C
March 31	2010	23.8 °C
April 5	1991	22.3 °C
April 6	1987	22.0 °C
April 9	2017	20.9 °C
April 10	2003	21.5 °C
April 12	2015	21.3 °C
April 12	2006	20.0 °C
April 12	1988	21.4 °C
April 12	1968	22.8 °C
April 12	1949	21.1 °C
April 13	1998	20.0 °C
April 14	2003	21.8 °C
April 14	1958	26.7 °C
April 15	2010	23.1 °C
April 15	1958	22.2 °C
April 16	2015	21.1 °C
April 16	2005	21.2 °C
April 16	1958	20.6 °C
April 16	1952	21.1 °C
April 16	1942	20.6 °C

Latest Days ≥ 20 °C

Date	Year	Temperature
November 6	2020	20.7 °C
November 4	2008	20.4 °C
November 4	1975	21.7 °C
November 3	2022	21.3 °C
October 30	2008	22.9 °C
October 27	1989	20.1 °C
October 27	1983	20.0 °C
October 26	1989	23.4 °C
October 24	2000	20.3 °C
October 24	1998	20.3 °C
October 24	1963	24.4 °C
October 23	1998	23.6 °C
October 23	1963	20.0 °C
October 23	1952	20.6 °C
October 22	1986	20.5 °C
October 22	1973	20.6 °C
October 22	1963	20.6 °C
October 22	1954	20.6 °C
October 22	1953	21.1 °C
October 22	1947	23.9 °C