Earliest and Latest Days at or Below 0° C in Thunder Bay

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 Thunder Bay, Ontario history. It is based on NOAA data from the years 1941–2024.

Earliest freezing temperature in Thunder Bay?

The earliest in a winter season that Thunder Bay, Ontario has recorded a low temperature of 0 °C or below is July 6 which happened in 1969.

Latest freezing temperature in Thunder Bay?

The latest in a winter season that Thunder Bay, Ontario has recorded a low temperature of 0 °C or below is June 21 which has happened twice, most recently in 1992.

Earliest Days ≤ 0 °C

Date	Year	Temperature
July 6	1969	0.0 °C
August 22	1950	0.0 °C
August 24	1942	0.0 °C
August 26	1950	-0.6 °C
August 29	1976	-1.1 °C
August 30	1976	0.0 °C
September 1	1976	-1.1 °C
September 1	1974	-0.6 °C
September 1	1951	-0.6 °C
September 1	1949	-1.1 °C
September 2	1976	-2.2 °C
September 2	1946	-0.6 °C
September 3	1997	-1.0 °C
September 3	1946	-2.2 °C
September 3	1942	0.0 °C
September 4	1946	-1.1 °C
September 5	1972	-1.1 °C
September 5	1942	0.0 °C
September 6	2011	-0.4 °C
September 6	2010	0.0 °C

Latest Days ≤ 0 °C

Date	Year	Temperature
June 21	1992	-0.7 °C
June 21	1950	-1.1 °C
June 14	2020	-1.4 °C
June 14	1958	-0.6 °C
June 13	2020	0.0 °C
June 13	1978	-0.1 °C
June 13	1969	0.0 °C
June 13	1946	-1.1 °C
June 12	1947	0.0 °C
June 11	1958	-1.1 °C
June 10	1980	-1.4 °C
June 10	1972	-1.1 °C
June 9	1978	-1.6 °C
June 9	1977	-0.7 °C
June 9	1966	0.0 °C
June 9	1958	-0.6 °C
June 9	1946	-1.1 °C
June 8	1995	-2.4 °C
June 8	1994	-0.6 °C
June 8	1983	-0.6 °C
June 8	1980	0.0 °C
June 8	1978	-0.1 °C
June 8	1949	-2.8 °C