Earliest and Latest Days of 100° F in Helena

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

Also see:

Earliest 100 degree day in Helena?

The earliest in the year that Helena, Montana had a high temperature of at least 100 °F is June 14 which happened in 2021.

Latest 100 degree day in Helena?

The latest in the year that Helena, Montana had a high temperature of at least 100 °F is September 7 which happened in 2022.

Earliest Days ≥ 100 °F

Date	Year	Temperature
June 14	2021	104 °F
June 21	1900	102 °F
June 25	1988	100 °F
June 27	2015	103 °F
June 28	2015	102 °F
June 29	2015	100 °F
June 30	2021	100 °F
July 1	2021	100 °F
July 1	1990	100 °F
July 2	2013	100 °F
July 3	2021	101 °F
July 5	2007	100 °F
July 5	1985	100 °F
July 5	1981	102 °F
July 8	2017	102 °F
July 8	2005	100 °F
July 9	1985	101 °F
July 9	1939	100 °F
July 10	1985	100 °F
July 10	1973	102 °F

Latest Days ≥ 100 °F

Date	Year	Temperature
September 7	2022	102 °F
August 24	1969	105 °F
August 18	2001	100 °F
August 17	2023	102 °F
August 17	2020	100 °F
August 15	2023	102 °F
August 15	2003	101 °F
August 12	1940	103 °F
August 10	2018	100 °F
August 10	2003	102 °F
August 9	1940	102 °F
August 7	2001	100 °F
August 7	1990	100 °F
August 6	2005	100 °F
August 6	1990	103 °F
August 6	1983	100 °F
August 6	1949	102 °F
August 5	1961	103 °F
August 4	1961	102 °F
August 3	2001	102 °F
August 3	1961	101 °F