Earliest and Latest Days of 30° C in London

This is a list of the earliest and latest days in the year with a high temperature of at least 30 °C in London, Ontario history. It is based on NOAA data from the years 1883–2024.

Also see:

Earliest 30 degree day in London?

The earliest in the year that London, Ontario had a high temperature of at least 30 °C is April 23 which happened in 1925.

Latest 30 degree day in London?

The latest in the year that London, Ontario had a high temperature of at least 30 °C is October 8 which happened in 2007.

Earliest Days ≥ 30 °C

Date	Year	Temperature
April 23	1925	30.0 °C
April 25	1915	30.0 °C
April 26	1915	30.6 °C
May 5	1949	31.1 °C
May 5	1895	31.7 °C
May 6	1949	31.1 °C
May 7	1930	30.0 °C
May 8	1896	30.6 °C
May 9	1896	31.7 °C
May 10	1896	30.6 °C
May 11	1896	30.0 °C
May 14	1962	30.0 °C
May 15	1962	31.1 °C
May 16	1991	30.2 °C
May 16	1962	31.1 °C
May 17	1977	30.2 °C
May 17	1962	31.7 °C
May 18	1962	31.1 °C
May 18	1949	30.0 °C
May 18	1911	31.1 °C
May 18	1903	30.0 °C

Latest Days ≥ 30 °C

Date	Year	Temperature
October 8	2007	30.3 °C
October 6	1946	30.0 °C
September 27	1923	30.0 °C
September 26	2017	31.5 °C
September 26	1923	31.1 °C
September 26	1920	31.1 °C
September 26	1908	33.3 °C
September 26	1900	30.6 °C
September 25	2017	31.5 °C
September 25	2007	31.3 °C
September 25	1920	33.3 °C
September 25	1908	33.9 °C
September 24	2017	32.2 °C
September 24	1908	30.0 °C
September 23	2017	32.2 °C
September 23	1908	30.0 °C
September 22	2017	30.7 °C
September 22	1941	30.6 °C
September 22	1931	30.6 °C
September 22	1920	31.1 °C
September 22	1914	30.6 °C
September 22	1908	32.2 °C
September 22	1895	32.2 °C