U.S. Frost Dates by Weather Station

NOAA station USW00093026 · Arizona

Frost Dates near Douglas, AZ

NOAA weather station Douglas Bisbee Inl Airport (USW00093026), Arizona · elevation 4105 ft (1251 m) · hardiness zone 8a*

Douglas is the nearest town to the station (8.6 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 27only 1 spring in 10 still has a frost later
  • Typical last frostApril 1150% chance of a frost after it
  • Typical first fall frostNovember 250% chance of a frost before it
  • Frost-free season203 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season near Douglas, AZSpring: a frost after March 27 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 21 in 1 year out of 10, before November 2 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 203 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 11First frost ~Nov 2Frost season near Douglas, AZSpring: a frost after March 27 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 21 in 1 year out of 10, before November 2 in half of the years, before November 15 in 9 years out of 10. Typical frost-free season: 203 days.JFMAMJJASONDLast frost ~Apr 11First frost ~Nov 2
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)April 27October 21
50% (typical)April 11November 2
90% (likely)March 27November 15
Frost-free season (32°F, 50% chance)
203 days
Hard frost (28°F), last in spring, 50% chance after
March 27
Hard frost (28°F), first in fall, 50% chance before
November 12

The last 15 years (2006–2020 normals)

Typical last frost April 11 (same as the 30-year normal), typical first fall frost November 3 (1 day later). Frost-free season 207 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 near Douglas: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 27, 20% April 23, 30% April 19, 40% April 15, 50% April 11, 60% April 8, 70% April 5, 80% April 2, 90% March 27. Observed last spring frost in recent years: 2023 April 6, 2024 April 7, 2025 April 20, 2026 March 7.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 27Apr 11Mar 272023: April 62024: April 72025: April 202026: March 7Fall near Douglas: chance of a frost before this dateFall, chance of a frost before the date: 10% October 21, 20% October 25, 30% October 29, 40% October 31, 50% November 2, 60% November 5, 70% November 8, 80% November 11, 90% November 15. Observed first fall frost in recent years: 2023 November 10, 2024 October 31, 2025 November 21.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 21Nov 2Nov 152023: November 102024: October 312025: November 21
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
2021no datano data
2022no datano data
2023April 6November 10
2024April 7October 31
2025April 20November 21
2026March 7season not over yet

What these dates mean

Setting out tender crops on March 27 in the Douglas area carries a 90% chance that a light frost will still occur, so planting that early is a gamble. The cautious spring date for tender crops is April 27, when only a 10% chance of a frost remains.

The 50% light-frost date is April 11, indicating a 50% chance of a frost later than this date, and the 50% fall date is November 2, indicating a 50% chance of a frost earlier than this date. For a cautious fall schedule, October 21 marks the point when there is only a 10% chance that a frost has arrived, making it the cutoff for finishing harvests. The hard-frost 50% dates are March 27 in spring and November 12 in fall; a hard frost at 28 °F can damage plants that survive a light frost at 32 °F, so it is a more severe threat.

How to read the probabilities

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

  • Spring: "10% after April 27" 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 21" 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 Douglas, AZNumbered nearest stations: 1 — Tombstone, AZ — 32 mi; 2 — near Sierra Vista Southeast, AZ — 39 mi; 3 — Benson, AZ — 47 mi; 4 — Animas, NM — 59 mi; 5 — San Simon, AZ — 62 mi.AZ25 mi · 40 km1. Tombstone, AZ — 32 mi12. near Sierra Vista Southeast, AZ — 39 mi23. Benson, AZ — 47 mi34. Animas, NM — 59 mi45. San Simon, AZ — 62 mi5
  1. Tombstone, AZ 32 mi (52 km)
  2. near Sierra Vista Southeast, AZ 39 mi (63 km)
  3. Benson, AZ 47 mi (76 km)
  4. Animas, NM 59 mi (95 km)
  5. San Simon, AZ 62 mi (100 km)

Sources

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

Station coordinates: 31.4583, -109.6061.