Flagstaff in September
In September, Flagstaff averages 24°C (75°F) during the day and 12°C (54°F) at night, with around 7 days of rain (39 mm total).
ShoulderConditions are comfortable for sightseeing without being sweltering. Occasional showers are likely but won't dominate.
It's peak hurricane season in Flagstaff during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.
How September compares to the rest of the year in Flagstaff
September is in the middle of the year for warmth in Flagstaff (4th of 12) and moderately rainy compared to the rest of the year (6th of 12). Daytime temperature runs 7°C above the annual average (17°C). September runs 3°C cooler than August (27°C) and cools 6°C in October (18°C).
September sunrise & sunset in Flagstaff
Times shown for Flagstaff local time (America/Phoenix), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in Flagstaff — September
Golden-hour and blue-hour windows for the 15th of September, in Flagstaff's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — Flagstaff in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Shoulder) and Flagstaff's popularity.
Crowds & pricing — September in Flagstaff
Flagstaff is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Why this tier: excellent tourism weather peak hazard season (1 active)
Sun & mosquito risk — September in Flagstaff
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Flagstaff in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 6°C / 42°F | -4°C / 24°F | 48 mm | 7 | — |
| February | 8°C / 46°F | -3°C / 26°F | 44 mm | 5 | — |
| March | 11°C / 51°F | -1°C / 31°F | 51 mm | 7 | — |
| April | 17°C / 62°F | 3°C / 38°F | 15 mm | 4 | — |
| May | 20°C / 68°F | 7°C / 44°F | 30 mm | 7 | — |
| June | 28°C / 82°F | 13°C / 56°F | 11 mm | 3 | — |
| July | 28°C / 83°F | 16°C / 60°F | 72 mm | 13 | — |
| August | 27°C / 80°F | 15°C / 58°F | 71 mm | 12 | — |
| September | 24°C / 75°F | 12°C / 54°F | 39 mm | 7 | — |
| October | 18°C / 64°F | 6°C / 43°F | 27 mm | 6 | — |
| November | 12°C / 53°F | 1°C / 34°F | 29 mm | 4 | — |
| December | 6°C / 44°F | -3°C / 27°F | 41 mm | 6 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for Flagstaff in September →
Frequently asked questions
How hot is Flagstaff in September?
In September, Flagstaff averages a high of 24°C (75°F) and a low of 12°C (54°F) — generally warm.
Does it rain a lot in Flagstaff in September?
September sees occasional rain in Flagstaff, with about 7 rainy days on average.
Is September a good time to visit Flagstaff?
September is warm. It suits travelers who are comfortable with warm weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for Flagstaff in September?
Pack light layers for warm days and cooler evenings. See the full September packing list for Flagstaff for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.