Earliest and Latest Days of 90° F in Boise

This is a list of the earliest and latest days in the year with a high temperature of at least 90 °F in Boise, Idaho history. It is based on NOAA data from the years 1911–2024.

Also see:

Earliest 90 degree day in Boise?

The earliest in the year that Boise, Idaho had a high temperature of at least 90 °F is April 17 which happened in 1936.

Latest 90 degree day in Boise?

The latest in the year that Boise, Idaho had a high temperature of at least 90 °F is October 10 which happened in 2015.

Earliest Days ≥ 90 °F

Date	Year	Temperature
April 17	1936	91 °F
April 22	2012	91 °F
April 22	1934	90 °F
April 23	2012	91 °F
April 24	1977	91 °F
April 25	1946	92 °F
April 27	2018	90 °F
April 27	1987	92 °F
April 28	1939	92 °F
April 29	1926	91 °F
April 30	2023	90 °F
May 2	1947	91 °F
May 3	1966	90 °F
May 4	1966	93 °F
May 5	1992	91 °F
May 5	1966	94 °F
May 6	2021	90 °F
May 6	1992	92 °F
May 6	1989	91 °F
May 6	1987	91 °F
May 6	1947	95 °F
May 6	1931	90 °F

Latest Days ≥ 90 °F

Date	Year	Temperature
October 10	2015	90 °F
October 9	2015	90 °F
October 3	1963	91 °F
October 2	2010	90 °F
October 2	1975	90 °F
October 2	1962	90 °F
October 1	2011	90 °F
October 1	2010	90 °F
October 1	2008	91 °F
October 1	1997	94 °F
October 1	1992	94 °F
September 30	2011	90 °F
September 30	2010	92 °F
September 30	2008	90 °F
September 30	1992	96 °F
September 30	1963	93 °F
September 30	1957	93 °F
September 29	2016	90 °F
September 29	1992	95 °F
September 29	1989	92 °F
September 29	1963	90 °F