Last Frost Date Flagstaff: Frost Dates, Late Frost Risk & Growing Season

When is the last spring frost and the first autumn frost in Flagstaff? Frost dates from 30 years of data, the risk of late frost, frost-free days and planting dates.

The frost season in Flagstaff

Last frost (average): May 5
In 1 year out of 10 it still freezes on May 17.
First frost: October 18
Frost-free season: 167 days
Frost after 15 May: in 13 % of years

Frost days per month in Flagstaff

January: 27.2 · -4 °C
February: 22.8 · -3 °C
March: 18.7 · -1 °C
April: 10 · 2 °C
May: 1.4 · 7 °C
June: 0 · 12 °C
July: 0 · 15 °C
August: 0 · 15 °C
September: 0 · 11 °C
October: 2.9 · 5 °C
November: 16.2 · 0 °C
December: 27 · -4 °C

No weather station nearby: plain grid values, which are often a little too cold – dates may therefore be late.
Daily minimum temperatures 2 m above ground over 30 years (1991–2020), NASA POWER; station data: Deutscher Wetterdienst (CC BY 4.0). Ground frost can form while the air at 2 m is still +2 to +3 °C.