Flagstaff, AZ Weather
Flagstaff hourly forecast: next 24 hours
Today's high of 70°F (21°C) is about 5°F (3°C) below the typical September high of 75°F (24°C).
Current conditions in detail
Flagstaff weather tomorrow (Wednesday, September 16)
Tomorrow in Flagstaff looks light rain shower, with a high of 63° and an overnight low of 54°. There is a 90% chance of rain - plan accordingly. Winds top out near 8 mph, and the UV index reaches 5 (moderate).
Flagstaff 14-day forecast
About the weather in Flagstaff
Seasons are the whole story in Flagstaff. The gap between an average July and an average January is 22°C - big day-to-night temperature swings and modest rainfall - which in practice means 83°F (29°C) afternoons at one end of the calendar and 40°F (5°C) at the other.
Flagstaff weather: quick facts
- Hottest month: July - highs near 83°F (29°C)
- Coldest month: January - highs near 40°F (5°C)
- Decade extremes (2015-2024): 96°F (36°C) high · -4°F (-20°C) low
- Wettest month: July (12 rainy days) · Sunniest: June (13.7 h sun/day)
- Climate type: semi-arid
- Annual swing: 22°C between the average warmest and coolest month · day to night: 12°C
- Snow: about 23 days a year
- Months with freezing average lows: 4
- Average humidity: 48%
Temperatures through the year
At its warmest, in July, Flagstaff runs to 83°F (29°C) in the afternoon and back to 60°F (16°C) by dawn. January bottoms out at 40°F (5°C) in daylight, 23°F (-5°C) after dark. The gridded 2015-2024 daily record for this location tops out at 96°F (36°C) and bottoms at -4°F (-20°C) - decade extremes, not all-time station records. Precipitation concentrates in July - 2.6 inches (66 mm) on 12 days - and thins out by June.
Rain, sun and snow
Three of the twelve months pair mild highs with fewer than twelve wet days; the longest unbroken run is August through September. Relative humidity averages 48% across the year, drier than all but 5% of the 3496 cities in our dataset.
Season by season
Spring (March through May)
Spring in Flagstaff stays on the cool side of mild, with daytime highs averaging 59°F (15°C) and nights around 36°F (2°C); rain comes on about 18 days over the three months, plus about 7 snowy days. Daylight is generous - around 11.9 hours of sun a day.
Summer (June through August)
Summer in Flagstaff sits firmly in the heat, with daytime highs averaging 82°F (28°C) and nights around 58°F (15°C); expect showers on roughly 26 days across the season. Daylight is generous - around 12.8 hours of sun a day.
Fall (September through November)
Fall in Flagstaff is mild, with daytime highs averaging 64°F (18°C) and nights around 43°F (6°C); rain comes on about 15 days over the three months, plus about 3 snowy days. Daylight is generous - around 10.5 hours of sun a day.
Winter (December through February)
Winter is brisk and cold here - highs near 43°F (6°C), nights near 24°F (-4°C), and expect showers on roughly 19 days across the season, plus about 13 snowy days.
Average temperatures in Flagstaff by month
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 40° | 23° | 8 | 2.0 in | 8.4 h/day | 66% |
| February | 44° | 25° | 6 | 1.9 in | 9.7 h/day | 58% |
| March | 49° | 29° | 8 | 2.1 in | 10.5 h/day | 57% |
| April | 61° | 36° | 4 | 0.6 in | 12.4 h/day | 39% |
| May | 68° | 43° | 6 | 1.2 in | 12.9 h/day | 36% |
| June | 81° | 56° | 3 | 0.6 in | 13.7 h/day | 27% |
| July | 83° | 60° | 12 | 2.6 in | 12.5 h/day | 43% |
| August | 80° | 58° | 11 | 2.4 in | 12.2 h/day | 50% |
| September | 75° | 53° | 6 | 1.3 in | 11.6 h/day | 45% |
| October | 64° | 43° | 6 | 1.2 in | 10.5 h/day | 47% |
| November | 52° | 33° | 3 | 1.1 in | 9.4 h/day | 49% |
| December | 43° | 26° | 5 | 1.4 in | 8.3 h/day | 56% |