Earliest and Latest Days of 90° F in Helena

This is a list of the earliest and latest days in the year with a high temperature of at least 90 °F in Helena, Montana history. It is based on NOAA data from the years 1893–2024.

Also see:

Earliest 90 degree day in Helena?

The earliest in the year that Helena, Montana had a high temperature of at least 90 °F is May 6 which happened in 1966.

Latest 90 degree day in Helena?

The latest in the year that Helena, Montana had a high temperature of at least 90 °F is September 25 which happened in 2001.

Earliest Days ≥ 90 °F

Date	Year	Temperature
May 6	1966	90 °F
May 12	2001	92 °F
May 15	1939	90 °F
May 16	2006	91 °F
May 16	1988	91 °F
May 17	2006	90 °F
May 18	2006	91 °F
May 19	1954	90 °F
May 20	2002	90 °F
May 24	2001	93 °F
May 27	1986	90 °F
May 27	1936	90 °F
May 28	2003	92 °F
May 28	1986	90 °F
May 28	1919	95 °F
May 29	2003	91 °F
May 29	1986	91 °F
May 29	1936	90 °F
May 30	1986	92 °F
June 1	1986	91 °F
June 1	1977	91 °F
June 1	1914	90 °F

Latest Days ≥ 90 °F

Date	Year	Temperature
September 25	2001	95 °F
September 23	1966	90 °F
September 21	1967	90 °F
September 21	1966	90 °F
September 20	1922	90 °F
September 19	2009	94 °F
September 18	1966	91 °F
September 17	1998	90 °F
September 16	2009	92 °F
September 16	1979	90 °F
September 15	2002	92 °F
September 15	2000	94 °F
September 14	2000	90 °F
September 14	1948	94 °F
September 14	1946	90 °F
September 13	1959	92 °F
September 12	2020	90 °F
September 12	2017	90 °F
September 12	2015	91 °F
September 12	1990	91 °F
September 12	1981	90 °F
September 12	1953	91 °F