Earliest and Latest Days of 100° F in Waterloo

This is a list of the earliest and latest days in the year with a high temperature of at least 100 °F in Waterloo, Iowa history. It is based on NOAA data from the years 1895–2024.

Also see:

Earliest 100 degree day in Waterloo?

The earliest in the year that Waterloo, Iowa had a high temperature of at least 100 °F is April 22 which happened in 1980.

Latest 100 degree day in Waterloo?

The latest in the year that Waterloo, Iowa had a high temperature of at least 100 °F is September 15 which happened in 1927.

Earliest Days ≥ 100 °F

Date	Year	Temperature
April 22	1980	100 °F
May 22	1925	101 °F
May 29	1934	101 °F
May 30	1934	100 °F
May 31	1934	108 °F
June 1	1934	101 °F
June 2	1934	106 °F
June 8	1985	102 °F
June 10	1933	101 °F
June 13	1987	100 °F
June 17	2021	100 °F
June 20	1988	102 °F
June 20	1933	103 °F
June 21	1988	103 °F
June 23	1934	101 °F
June 23	1931	103 °F
June 24	1937	102 °F
June 24	1931	102 °F
June 25	1934	101 °F
June 25	1931	104 °F

Latest Days ≥ 100 °F

Date	Year	Temperature
September 15	1927	100 °F
September 7	1939	102 °F
September 7	1922	101 °F
September 6	1939	100 °F
September 6	1922	102 °F
September 4	2023	100 °F
September 4	1925	101 °F
September 3	2023	100 °F
September 3	1939	101 °F
September 2	1925	100 °F
September 2	1913	100 °F
August 24	2023	103 °F
August 24	1936	100 °F
August 23	2023	105 °F
August 22	1916	100 °F
August 21	1916	101 °F
August 20	1916	100 °F
August 19	1983	100 °F
August 18	1936	110 °F
August 17	1988	105 °F