Phoenix · August
Run in the pre-dawn.
Average highs hit 103°F. August is the hottest stretch of the year. Heat builds fast after sunrise — the pre-dawn hour is the only reliably comfortable window.
Avg high / low
103° / 82°F
Humidity
37%
Rain days
8/mo
Wind
11 mph
What August feels like in Phoenix
Sunrise
05:51
Mid-month average
Sunset
19:12
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 Phoenix in August
The kit for August in Phoenix: light, breathable, and moisture-wicking — singlet or short-sleeve only.
August vs the surrounding months
vs July
-2° avg high
-1 rain days
Phoenix in July →
August
103°F avg high
8 rain days
Best: pre-dawn
vs September
+5° avg high
+2 rain days
Phoenix in September →
Frequently Asked Questions
What is the best time of day to run in Phoenix in August?+
Pre-dawn. Heat builds fast after sunrise — the pre-dawn hour is the only reliably comfortable window.
What's the average temperature in Phoenix in August?+
Average high 103°F, average low 82°F.
How does August compare to surrounding months in Phoenix?+
Compared to July (avg high 106°F), August is cooler. Compared to September (avg high 99°F), August is warmer.
Does it rain often in Phoenix in August?+
Expect about 8 measurable rain days in August, on average.