U.S. Frost Dates by Weather Station

NOAA station USC00020586 · Arizona

Frost Dates for Bagdad, AZ

NOAA weather station Bagdad (USC00020586), Arizona · elevation 3935 ft (1199 m) · hardiness zone 8b*

  • Lower-risk planting dateafter May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 750% chance of a frost after it
  • Typical first fall frostNovember 1250% chance of a frost before it
  • Frost-free season217 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Bagdad, AZSpring: a frost after March 14 in 9 years out of 10, after April 7 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 26 in 1 year out of 10, before November 12 in half of the years, before November 25 in 9 years out of 10. Typical frost-free season: 217 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 7First frost ~Nov 12Frost season at Bagdad, AZSpring: a frost after March 14 in 9 years out of 10, after April 7 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 26 in 1 year out of 10, before November 12 in half of the years, before November 25 in 9 years out of 10. Typical frost-free season: 217 days.JFMAMJJASONDLast frost ~Apr 7First frost ~Nov 12
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 3October 26
50% (typical)April 7November 12
90% (likely)March 14November 25
Frost-free season (32°F, 50% chance)
217 days
Hard frost (28°F), last in spring, 50% chance after
March 13
Hard frost (28°F), first in fall, 50% chance before
November 22

The last 15 years (2006–2020 normals)

Typical last frost April 3 (4 days earlier than the 30-year normal), typical first fall frost November 13 (1 day later). Frost-free season 222 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring at Bagdad: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 24, 30% April 18, 40% April 11, 50% April 7, 60% April 3, 70% March 31, 80% March 23, 90% March 14. Observed last spring frost in recent years: 2022 April 14, 2023 April 8, 2024 April 9, 2025 April 6, 2026 February 24.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1May 3Apr 7Mar 142022: April 142023: April 82024: April 92025: April 62026: February 24Fall at Bagdad: chance of a frost before this dateFall, chance of a frost before the date: 10% October 26, 20% November 1, 30% November 5, 40% November 9, 50% November 12, 60% November 14, 70% November 17, 80% November 21, 90% November 25. Observed first fall frost in recent years: 2021 November 28, 2022 November 4, 2023 November 25, 2024 October 31, 2025 December 2.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 26Nov 12Nov 252021: November 282022: November 42023: November 252024: October 312025: December 2
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021incomplete recordNovember 28
2022April 14November 4
2023April 8November 25
2024April 9October 31
2025April 6December 2
2026February 24season not over yet

What these dates mean

The 217 days between the 50% dates in Bagdad, April 7 and November 12, mark the interval in which a light frost is less likely than not. The 50% date in spring, April 7, signals an even-odds point for a light frost occurring later, while the 50% date in fall, November 12, signals an even-odds point for a light frost occurring earlier. Gardeners can view these dates as the midpoint of the light-frost risk window for the season.

For a cautious schedule, the spring light-frost cautious date is May 3, which carries only a 10 % chance of a frost later, and the fall cautious date is October 26, with only a 10 % chance of a frost earlier. The hard-frost median dates—March 13 in spring and November 22 in fall—show when a 28 °F frost has a 50 % chance. A hard frost matters more than a light frost because it can cause far more severe damage to tender plants.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after May 3" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before October 26" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Bagdad, AZNumbered nearest stations: 1 — Walnut Creek, AZ — 31 mi; 2 — Prescott, AZ — 42 mi; 3 — Seligman, AZ — 53 mi; 4 — Cordes, AZ — 61 mi; 5 — Jerome, AZ — 61 mi.25 mi · 40 km1. Walnut Creek, AZ — 31 mi12. Prescott, AZ — 42 mi23. Seligman, AZ — 53 mi34. Cordes, AZ — 61 mi45. Jerome, AZ — 61 mi5
  1. Walnut Creek, AZ 31 mi (50 km)
  2. Prescott, AZ 42 mi (68 km)
  3. Seligman, AZ 53 mi (86 km)
  4. Cordes, AZ 61 mi (98 km)
  5. Jerome, AZ 61 mi (99 km)

Sources

* Hardiness zone 8b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 34.5975, -113.1744.