Boise, ID weather in May
May in Boise: mild, with some rain. Highs 72°F, lows 48°F, rain on about 8 days. A great month for outdoor plans.
- Normal high
- 72°F
- Normal low
- 48°F
- Wet days
- 8
- 1.4 in total
- Muggy days
- 0
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 67°F | 76°F |
| Normal low | 43°F | 51°F |
| Chance of a wet day | 28% | 25% |
| Sunrise / sunset | 6:37 am / 8:46 pm | 6:06 am / 9:18 pm |
| Daylight | 14.2 h | 15.2 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Mountain Time).
A typical May day
- 6 am49°Fdew point 38°F
- 9 am58°Fdew point 39°F
- Noon66°Fdew point 38°F
- 3 pm70°Fdew point 36°F
- 6 pm69°Fdew point 35°F
- 9 pm61°Fdew point 38°F
NOAA hourly normals (local standard time) from Boise Air Terminal (4 mi away); average wind 8 mph; clear or few clouds in 72% of daytime hours, mostly cloudy or overcast in 21%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F16 of 31
- Hot dayshigh 90°F or more1 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow8 of 31
- Notable rainat least 0.10 in4 of 31
- Freezing nightslow 32°F or below1 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain in May
Normal precipitation is 1.4 in; a dry May brings about 0.8 in and a wet one about 1.9 in (25th and 75th percentiles). About 1 day brings half an inch or more.
How May varies from year to year
- Warmest May, 1991-20201992: average high 82°F
- Coolest May2010: average high 65°F
- Wettest May1998: 4.4 in
- Driest May1992: no measurable precipitation
- Highest reading99°F (May 28, 2003)
- Lowest reading27°F (May 10, 1999)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 62°F | 72°F | 81°F |
| Normal low | 40°F | 48°F | 54°F |
| Wet days | 9 | 8 | 5 |
| Comfortable days | 10 | 16 | 12 |
| Daylight | 13.4 h | 14.7 h | 15.4 h |
Highs change by +10°F from April and +9°F into June.
Nearby alternatives in May
- Cooler: Sun Valley, ID93 mi · high 62°F · 8 wet days
How Boise ranks in May
- Normal high229th warmest of 378 cities; 1st of 2 in Idaho
- Wet days155th driest of 378
- Comfortable days62nd most of 339
What to pack for Boise in May
- A rain jacket or umbrella – rain on about 8 days
Heating and cooling
May has 200 heating degree days and 42 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How hot is Boise in May?
The normal high is 72°F and the normal low is 48°F. From 1991 to 2020 the hottest May reading was 99°F (May 28, 2003).
Does it rain a lot in Boise in May?
About 8 days in May have at least 0.01 in of precipitation, and the normal total is 1.5 in. The wettest May in 1991-2020 was in 1998 (4.4 in); the driest was in 1992, with no measurable precipitation.
Is May a good time to visit Boise?
May ranks 1st of 12 months on our comfort score for Boise (76 out of 100). It has about 16 comfortable days and about 1 day at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Boise Air Terminal (USW00024131), 3.7 mi SSW of the city center, 2,814 ft (114 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Boise Air Terminal/Gowen Fd Airport (726810-24131), 3.7 mi SSW of the city center, 2,823 ft (123 ft higher than the city). Hourly observations, 1991-2020.