Weather on May 20
Boise, ID
55 Years of Data
Avg High
71°F
Avg Low
46°F
Warmest
2023
76°F avg
Coldest
1971
43°F avg
About This Date
May 20th in Boise, ID typically brings pleasant spring weather, with average highs around 71°F and lows near 46°F — a 25°F daily swing. Over 55 years of records, the warmest May 20th was in 2023 (76°F average), while the coldest was 1971 (43°F) — a 33°F range across recorded history. Rain or other precipitation has occurred on about 36% of May 20th dates historically, with the wettest May 20th recording 2.03" of rain. The last decade has been 1.9°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.9°F cooler on this date compared to 20-30 years ago.
Planning for May 20th in Boise, ID? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
0.5°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 66° | 46° | 56° | — | — |
| 2024 | 68° | 43° | 55° | — | — |
| 2023warmest | 92° | 60° | 76° | — | — |
| 2022 | 65° | 38° | 51° | — | — |
| 2021 | 63° | 40° | 51° | — | — |
| 2020 | 51° | 45° | 48° | 2.03" | — |
| 2019 | 62° | 48° | 55° | 0.99" | — |
| 2018 | 72° | 56° | 64° | 0.51" | — |
| 2017 | 77° | 52° | 64° | — | — |
| 2016 | 55° | 45° | 50° | 0.2" | — |
| 2015 | 70° | 54° | 62° | 0.23" | — |
| 2014 | 75° | 42° | 59° | — | — |
| 2013 | 74° | 43° | 58° | — | — |
| 2012 | 84° | 56° | 70° | — | — |
| 2011 | 76° | 49° | 62° | — | — |
| 2010 | 60° | 43° | 51° | 0.18" | — |
| 2009 | 68° | 45° | 56° | — | — |
| 2008 | 88° | 48° | 68° | 0.84" | — |
| 2007 | 71° | 52° | 61° | 0.08" | — |
| 2006 | 78° | 59° | 69° | 0.74" | — |
| 2005 | 68° | 49° | 58° | 0.18" | — |
| 2004 | 70° | 45° | 57° | 0.18" | — |
| 2003 | 74° | 43° | 58° | — | — |
| 2002 | 61° | 44° | 52° | — | — |
| 2001 | 67° | 45° | 56° | — | — |
| 2000 | 79° | 49° | 64° | — | — |
| 1999 | 78° | 53° | 66° | 0.1" | — |
| 1998 | 71° | 46° | 59° | — | — |
| 1997 | 83° | 52° | 67° | — | — |
| 1996 | 64° | 39° | 52° | — | — |
| 1995 | 80° | 43° | 61° | — | — |
| 1994 | 63° | 49° | 56° | 0.18" | — |
| 1993 | 83° | 59° | 71° | 0.1" | — |
| 1992 | 69° | 51° | 60° | — | — |
| 1991 | 66° | 44° | 55° | — | — |
| 1990 | 65° | 48° | 56° | 0.56" | — |
| 1989 | 75° | 42° | 59° | — | — |
| 1988 | 80° | 40° | 60° | — | — |
| 1987 | 65° | 38° | 51° | — | — |
| 1986 | 80° | 54° | 67° | 0.13" | — |
| 1985 | 70° | 47° | 58° | 1.42" | — |
| 1984 | 70° | 47° | 58° | — | — |
| 1983 | 73° | 40° | 56° | — | — |
| 1982 | 74° | 34° | 54° | — | — |
| 1981 | 65° | 48° | 56° | 0.71" | — |
| 1980 | 88° | 53° | 70° | — | — |
| 1979 | 80° | 40° | 60° | — | — |
| 1978 | 78° | 45° | 61° | — | — |
| 1977 | 70° | 40° | 55° | — | — |
| 1976 | 66° | 34° | 50° | — | — |
| 1975 | 66° | 38° | 52° | — | — |
| 1974 | 63° | 45° | 54° | — | — |
| 1973 | 67° | 48° | 57° | 0.03" | — |
| 1972 | 75° | 51° | 63° | 0.18" | — |
| 1971coldest | 54° | 33° | 43° | — | — |
55 years of data from BOISE AIR TERMINAL