Boise · August
Run in the morning.
Average high is 91°F with a 64°F overnight low. Dry air (32% humidity) makes the heat more bearable than the numbers suggest. Dry month — only 3 measurable rain days on average. Dry heat climbs fast after sunrise — get out in the cooler morning hours.
Avg high / low
91° / 64°F
Humidity
32%
Rain days
3/mo
Wind
11 mph
What August feels like in Boise
Sunrise
06:51
Mid-month average
Sunset
20:46
Mid-month average
Time-of-day breakdown
Morning
Cool relative to the day's peak, but heat builds fast. By 10 AM you're already chasing comfort.
Midday
Heat peaks here. Skip unless you've got shade and pace tolerance.
Evening
Cools off after sunset but still warm. Good for easy efforts; avoid hard intervals if you're chasing pace.
What to wear running in Boise in August
The kit for August in Boise: light, breathable, and moisture-wicking — singlet or short-sleeve only.
August vs the surrounding months
vs July
-3° avg high
+1 rain days
Boise in July →
August
91°F avg high
3 rain days
Best: morning
vs September
+11° avg high
-2 rain days
Boise in September →
Frequently Asked Questions
What is the best time of day to run in Boise in August?+
Morning. Dry heat climbs fast after sunrise — get out in the cooler morning hours.
What's the average temperature in Boise in August?+
Average high 91°F, average low 64°F.
How does August compare to surrounding months in Boise?+
Compared to July (avg high 94°F), August is cooler. Compared to September (avg high 80°F), August is warmer.
Does it rain often in Boise in August?+
Expect about 3 measurable rain days in August, on average.