Flagstaff, AZ weather in August
Flagstaff is mild in August, with frequent rain: highs average 79°F and nights drop to about 51°F. Rain falls on about 13 days. This is the peak of the warm season in Flagstaff.
- Normal high
- 79°F
- Normal low
- 51°F
- Wet days
- 13
- 3.0 in total
- Daylight
- 13.4 h
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 81°F | 78°F |
| Normal low | 53°F | 48°F |
| Chance of a wet day | 44% | 38% |
| Sunrise / sunset | 5:35 am / 7:30 pm | 5:58 am / 6:55 pm |
| Daylight | 13.9 h | 12.9 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Arizona time (no daylight saving)).
A typical August day
- 6 am50°Fdew point 44°F
- 9 am72°Fdew point 47°F
- Noon78°Fdew point 44°F
- 3 pm79°Fdew point 43°F
- 6 pm75°Fdew point 44°F
- 9 pm62°Fdew point 45°F
NOAA hourly normals (local standard time) from Grand Canyon NP Airport (59 mi away); average wind 5 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F (temperature only: no humidity station nearby)17 of 31
- Hot dayshigh 90°F or more1 of 31
- Wet daysat least 0.01 in of rain or melted snow13 of 31
- Notable rainat least 0.10 in7 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 3.0 in; a dry August brings about 2.4 in and a wet one about 3.6 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How August varies from year to year
- Warmest August, 1991-20202020: average high 86°F
- Coolest August2014: average high 75°F
- Wettest August2016: 6.3 in
- Driest August2020: 0.3 in
- Highest reading93°F (August 16, 2020)
- Lowest reading35°F (August 9, 2009)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 82°F | 79°F | 74°F |
| Normal low | 51°F | 51°F | 43°F |
| Wet days | 12 | 13 | 8 |
| Comfortable days | 11 | 17 | 24 |
| Daylight | 14.3 h | 13.4 h | 12.4 h |
Highs change by -3°F from July and -5°F into September.
Nearby alternatives in August
- Warmer: Sedona, AZ24 mi · high 94°F · 9 wet days
- Drier: Sedona, AZ24 mi · high 94°F · 9 wet days
How Flagstaff ranks in August
- Normal high318th warmest of 378 cities; 13th of 13 in Arizona
- Wet days334th driest of 378
What to pack for Flagstaff in August
- Layers – afternoons near 79°F but nights near 51°F
- A rain jacket or umbrella – rain on about 13 days
Heating and cooling
August has 44 heating degree days and 43 cooling degree days (base 65°F), 1% of the year's total heating and cooling demand.
Questions
How hot is Flagstaff in August?
The normal high is 79°F and the normal low is 51°F. From 1991 to 2020 the hottest August reading was 93°F (August 16, 2020).
Does it rain a lot in Flagstaff in August?
About 13 days in August have at least 0.01 in of precipitation, and the normal total is 3.0 in. The wettest August in 1991-2020 was in 2016 (6.3 in); the driest was in 2020 (0.3 in).
Is August a good time to visit Flagstaff?
August ranks 4th of 12 months on our comfort score for Flagstaff (72 out of 100). It has about 17 comfortable days (judged by temperature only) and about 1 day at 90°F or hotter. The best months are May and September.
Where the numbers come from
- Temperature, rain, snowfall and frost dates: Flagstaff Pulliam Airport (USW00003103), 3.8 mi SSW of the city center, 7,003 ft (103 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Snow depth: Sunset Crater Nm (USC00028329), 13 mi NNE of the city center, 6,980 ft (80 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Grand Canyon NP Airport (USW00003195), 59 mi NNW of the city center, 6,606 ft (294 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Not available for this location: cloud cover and daily humidity and wind (no station close enough or similar enough in elevation).