Flagstaff weather by month
The best time to visit Flagstaff is June, August and September — 94/100 in September, 24°C and 5 rainy days. The best season is summer, June to August (87/100 on average).
The worst month is January at 53/100 — cold, a little rain, clean air. See January →
Updated September 2026 · climate normals from ERA5 reanalysis
Planning the wider trip? Best time to visit United States →
Best season: June to August (87/100 on average) · worst January (53/100)
- Days
- 24°C
- Nights
- 9°C
- Wet days
- 5
- Sun
- 11.1 h
- Humidity
- 49%
- Daylight
- 12 h

Flagstaff, month by month
Comfort score out of 100 for the kind of trip Flagstaff is best for, the average high, rainy days and hours of sun a day from the climate normals, and how busy it tends to be.
What's on in Flagstaff through the year
Festivals, natural spectacles, holidays and the seasons to watch out for — curated and sourced. The month pages carry the detail.
- May
- Fire restrictions and smoke1 May – 10 Jul (usually)Hazard
- June
- Southwest monsoon15 Jun – 30 SepSeason
- July
- Fourth of July in the mountains3–5 JulHoliday
- September
- Flagstaff Festival of Science25 Sep – 4 OctFestival
- Flagstaff Star Party1–3 OctFestival
- Aspen colour on the Peaks20 Sep – 15 Oct (usually)Nature
- November
- Thanksgiving25–29 NovHoliday
- Arizona Snowbowl season15 Nov – 10 Apr (usually)Opening
- December
- Christmas and New Year24 Dec – 1 JanHoliday
Crowds in Flagstaff in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Peak crowdsAspen colour on the Peaks, Summer break in United States(estimated)
Peak crowdsBusyShoulder seasonQuiet
Traveller notes on Flagstaff
What people who have been say about the place — the year-round notes first, then month by month.
Forum posters cite an average March daytime high around 43F with nighttime lows in the teens, describing March as still genuinely winter in Flagstaff - posters are direct that snow at some point during the month is close to guaranteed, unless an unusually warm stretch arrives early. Posters describe a typical late-winter snowfall here as brief, usually gone within a day or two, with roads cleared quickly except during a major storm, which can shut down travel for several days at a time. Posters consistently recommend monitoring forecasts roughly a week ahead and building real flexibility into a March itinerary. Posters generally rate March as a high-precipitation, snow-capable month, workable for a visit but requiring genuine weather-contingency planning.
Late September into early October is the window regulars name for this part of Arizona: temperatures cooling, patterns fairly stable and mostly sunny, crowds thinning. Flagstaff sits at about 7,000 feet, which is the whole point — days near 25°C while the desert below is still hot, and nights dropping to about 13, cold enough that a jacket or fleece is wanted early and late, with freezing possible in the second half of the month. The third week of September is when aspen, oak and birch begin turning on the Grand Canyon's North Rim. Layers you can shed is the standing advice.
Add your own note from Flagstaff's card on the map.