Earliest and Latest Days of 100° F in Rockford

This is a list of the earliest and latest days in the year with a high temperature of at least 100 °F in Rockford, Illinois history. It is based on NOAA data from the years 1893–2024.

Also see:

Earliest 100 degree day in Rockford?

The earliest in the year that Rockford, Illinois had a high temperature of at least 100 °F is May 31 which happened in 1934.

Latest 100 degree day in Rockford?

The latest in the year that Rockford, Illinois had a high temperature of at least 100 °F is September 15 which happened in 1939.

Earliest Days ≥ 100 °F

Date	Year	Temperature
May 31	1934	106 °F
June 1	1934	106 °F
June 3	1934	100 °F
June 20	1988	101 °F
June 20	1933	100 °F
June 21	2022	100 °F
June 21	1988	100 °F
June 24	1923	100 °F
June 25	1988	101 °F
June 26	1931	100 °F
June 27	1933	103 °F
June 28	2012	100 °F
June 28	1934	103 °F
June 28	1931	100 °F
June 29	1931	103 °F
June 30	1931	102 °F
June 30	1913	100 °F
July 1	1956	100 °F
July 1	1931	101 °F
July 4	2012	102 °F
July 4	1921	100 °F
July 4	1911	101 °F

Latest Days ≥ 100 °F

Date	Year	Temperature
September 15	1939	102 °F
September 14	1939	101 °F
September 8	1922	101 °F
September 7	1939	103 °F
September 7	1922	100 °F
September 6	1922	102 °F
September 5	1925	100 °F
September 4	1925	101 °F
September 3	1913	100 °F
September 2	1953	101 °F
September 1	1953	102 °F
August 31	1953	101 °F
August 24	1948	100 °F
August 24	1947	102 °F
August 23	1947	101 °F
August 22	1936	101 °F
August 21	1955	100 °F
August 21	1916	100 °F
August 20	1947	100 °F
August 19	1947	100 °F
August 19	1916	100 °F