Flagstaff, AZ Climate & Monthly Averages
Flagstaff has a semi-arid climate. July is the hottest month, averaging 83° by day; January is the coldest at 40°.
Winter sets the pace 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.
July
83° by day 60° at nightJanuary
40° by day 23° at nightThe cold-weather pattern in numbers
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.
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.
More climate facts for Flagstaff
- 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%
From snow season to the warmest stretch in Flagstaff
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.
The coldest and warmest values in the dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.
Planning around winter in Flagstaff
The easier weather window
The best time to visit Flagstaff is generally April to June and September to October, when temperatures sit either side of the peak heat rather than in it. Daytime temperatures in that window sit near 70°F (21°C), with rain on about 5 days a month. For the same question asked the other way round, see where else is warm in April.
Cold-weather packing
Pack for Flagstaff with light clothing for the warm months, a heavy insulated coat, hat and gloves for winter and rain gear if you travel around July. Note the gap between afternoon and night: July pairs 83°F (29°C) with 60°F (16°C).
Monthly highs, lows and seasonal change
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 40° | 23° | 8 | 2.0 in | 8.4 h/day | 10.0 h | 25% | 66% |
| February | 44° | 25° | 6 | 1.9 in | 9.7 h/day | 10.9 h | 20% | 58% |
| March | 49° | 29° | 8 | 2.1 in | 10.5 h/day | 11.9 h | 25% | 57% |
| April | 61° | 36° | 4 | 0.6 in | 12.4 h/day | 13.0 h | 13% | 39% |
| May | 68° | 43° | 6 | 1.2 in | 12.9 h/day | 14.0 h | 20% | 36% |
| June | 81° | 56° | 3 | 0.6 in | 13.7 h/day | 14.5 h | 11% | 27% |
| July | 83° | 60° | 12 | 2.6 in | 12.5 h/day | 14.3 h | 38% | 43% |
| August | 80° | 58° | 11 | 2.4 in | 12.2 h/day | 13.5 h | 36% | 50% |
| September | 75° | 53° | 6 | 1.3 in | 11.6 h/day | 12.3 h | 21% | 45% |
| October | 64° | 43° | 6 | 1.2 in | 10.5 h/day | 11.2 h | 18% | 47% |
| November | 52° | 33° | 3 | 1.1 in | 9.4 h/day | 10.3 h | 11% | 49% |
| December | 43° | 26° | 5 | 1.4 in | 8.3 h/day | 9.8 h | 17% | 56% |
The route from winter to summer, month by month
Each card shows the average high and low. The bar places that month between Flagstaff's coldest night and warmest afternoon.
January
- Rain
- 8 days
- Sunshine
- 8.4 h
- Daylight
- 10.0 h
- Snow
- 5 days
February
- Rain
- 6 days
- Sunshine
- 9.7 h
- Daylight
- 10.9 h
- Snow
- 4 days
March
- Rain
- 8 days
- Sunshine
- 10.5 h
- Daylight
- 11.9 h
- Snow
- 5 days
April
- Rain
- 4 days
- Sunshine
- 12.4 h
- Daylight
- 13.0 h
- Snow
- 1 day
May
- Rain
- 6 days
- Sunshine
- 12.9 h
- Daylight
- 14.0 h
- Snow
- 1 day
June
- Rain
- 3 days
- Sunshine
- 13.7 h
- Daylight
- 14.5 h
July
- Rain
- 12 days
- Sunshine
- 12.5 h
- Daylight
- 14.3 h
August
- Rain
- 11 days
- Sunshine
- 12.2 h
- Daylight
- 13.5 h
September
- Rain
- 6 days
- Sunshine
- 11.6 h
- Daylight
- 12.3 h
October
- Rain
- 6 days
- Sunshine
- 10.5 h
- Daylight
- 11.2 h
November
- Rain
- 3 days
- Sunshine
- 9.4 h
- Daylight
- 10.3 h
- Snow
- 2 days
December
- Rain
- 5 days
- Sunshine
- 8.3 h
- Daylight
- 9.8 h
- Snow
- 3 days
Looking for warmer alternatives? Browse warm places by month, or compare Flagstaff's coolest part of the year: January, December, February.
Where Flagstaff sits among other climates
- The city sees 11.0 hours of sunshine on an average day - sunnier than 95% of the 3496 cities we track.
- Afternoons run 12°C above the following night - a bigger day-to-night gap than 89% of the 3496 cities we track.
These comparisons use the same ten-year window for every city in the dataset.