Weather on July 21
Boise, ID
55 Years of Data
Avg High
94°F
Avg Low
61°F
Warmest
2024
90°F avg
Coldest
1972
63°F avg
About This Date
July 21st in Boise, ID typically brings hot summer weather, with average highs around 94°F and lows near 61°F — a 33°F daily swing. Over 55 years of records, the warmest July 21st was in 2024 (90°F average), while the coldest was 1972 (63°F) — a 27°F range across recorded history. Rain or other precipitation has occurred on about 13% of July 21st dates historically, with the wettest July 21st recording 0.53" of rain. The last decade has been 1.3°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.3°F warmer on this date compared to 20-30 years ago.
Planning for July 21st in Boise, ID? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 62° | 70° | — | — |
| 2024warmest | 108° | 73° | 90° | — | — |
| 2023 | 105° | 70° | 87° | — | — |
| 2022 | 100° | 64° | 82° | — | — |
| 2021 | 95° | 68° | 82° | 0.03" | — |
| 2020 | 99° | 63° | 81° | — | — |
| 2019 | 97° | 57° | 77° | — | — |
| 2018 | 97° | 59° | 78° | — | — |
| 2017 | 94° | 58° | 76° | — | — |
| 2016 | 100° | 64° | 82° | — | — |
| 2015 | 95° | 66° | 81° | 0.05" | — |
| 2014 | 83° | 71° | 77° | — | — |
| 2013 | 99° | 62° | 80° | — | — |
| 2012 | 96° | 61° | 78° | — | — |
| 2011 | 88° | 58° | 73° | — | — |
| 2010 | 95° | 60° | 78° | — | — |
| 2009 | 99° | 65° | 82° | — | — |
| 2008 | 95° | 71° | 83° | — | — |
| 2007 | 97° | 64° | 80° | — | — |
| 2006 | 104° | 68° | 86° | — | — |
| 2005 | 107° | 68° | 88° | — | — |
| 2004 | 93° | 61° | 77° | — | — |
| 2003 | 101° | 65° | 83° | — | — |
| 2002 | 95° | 62° | 79° | — | — |
| 2001 | 86° | 55° | 71° | — | — |
| 2000 | 102° | 67° | 84° | — | — |
| 1999 | 90° | 54° | 72° | — | — |
| 1998 | 100° | 63° | 81° | — | — |
| 1997 | 101° | 68° | 84° | — | — |
| 1996 | 90° | 56° | 73° | — | — |
| 1995 | 90° | 63° | 76° | — | — |
| 1994 | 101° | 68° | 84° | — | — |
| 1993 | 78° | 54° | 66° | 0.08" | — |
| 1992 | 84° | 53° | 69° | — | — |
| 1991 | 93° | 60° | 77° | — | — |
| 1990 | 95° | 64° | 80° | — | — |
| 1989 | 91° | 63° | 77° | 0.05" | — |
| 1988 | 103° | 59° | 81° | — | — |
| 1987 | 86° | 54° | 70° | 0.28" | — |
| 1986 | 92° | 52° | 72° | — | — |
| 1985 | 97° | 58° | 77° | — | — |
| 1984 | 84° | 53° | 69° | — | — |
| 1983 | 90° | 53° | 71° | — | — |
| 1982 | 94° | 58° | 76° | — | — |
| 1981 | 90° | 50° | 70° | — | — |
| 1980 | 96° | 58° | 77° | — | — |
| 1979 | 88° | 72° | 80° | — | — |
| 1978 | 87° | 53° | 70° | — | — |
| 1977 | 100° | 73° | 87° | — | — |
| 1976 | 89° | 56° | 72° | — | — |
| 1975 | 95° | 63° | 79° | 0.03" | — |
| 1974 | 98° | 63° | 80° | — | — |
| 1973 | 80° | 58° | 69° | — | — |
| 1972coldest | 73° | 53° | 63° | 0.53" | — |
| 1971 | 96° | 63° | 79° | — | — |
55 years of data from BOISE AIR TERMINAL