U.S. Frost Dates by Weather Station

NOAA station USC00022140 · Arizona

Frost Dates near Sierra Vista Southeast, AZ

NOAA weather station Coronado National Memorial (USC00022140), Arizona · elevation 5242 ft (1598 m) · hardiness zone 8b*

Sierra Vista Southeast is the nearest town to the station (7.8 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 750% chance of a frost after it
  • Typical first fall frostNovember 950% chance of a frost before it
  • Frost-free season213 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season near Sierra Vista Southeast, AZSpring: a frost after March 19 in 9 years out of 10, after April 7 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 9 in half of the years, before November 27 in 9 years out of 10. Typical frost-free season: 213 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 7First frost ~Nov 9Frost season near Sierra Vista Southeast, AZSpring: a frost after March 19 in 9 years out of 10, after April 7 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 9 in half of the years, before November 27 in 9 years out of 10. Typical frost-free season: 213 days.JFMAMJJASONDLast frost ~Apr 7First frost ~Nov 9
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 27October 25
50% (typical)April 7November 9
90% (likely)March 19November 27
Frost-free season (32°F, 50% chance)
213 days
Hard frost (28°F), last in spring, 50% chance after
March 19
Hard frost (28°F), first in fall, 50% chance before
November 20

The last 15 years (2006–2020 normals)

Typical last frost April 5 (2 days earlier than the 30-year normal), typical first fall frost November 16 (7 days later). Frost-free season 223 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 Sierra Vista Southeast: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 27, 20% April 20, 30% April 15, 40% April 11, 50% April 7, 60% April 4, 70% March 31, 80% March 27, 90% March 19. Observed last spring frost in recent years: 2021 March 27, 2022 April 13, 2023 April 5, 2024 March 27, 2025 April 5, 2026 March 6.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 27Apr 7Mar 192021: March 272022: April 132023: April 52024: March 272025: April 52026: March 6Fall near Sierra Vista Southeast: chance of a frost before this dateFall, chance of a frost before the date: 10% October 25, 20% October 30, 30% November 2, 40% November 5, 50% November 9, 60% November 12, 70% November 16, 80% November 20, 90% November 27. Observed first fall frost in recent years: 2021 December 11, 2022 October 31, 2023 November 26, 2024 November 5.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 25Nov 9Nov 272021: December 112022: October 312023: November 262024: November 5
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
2021March 27December 11
2022April 13October 31
2023April 5November 26
2024March 27November 5
2025April 5incomplete record
2026March 6season not over yet

What these dates mean

October 25 is the cautious fall date for finishing the harvest of tender crops in the Sierra Vista Southeast area. In spring, the cautious date for setting out tender crops is April 27, when there is only a 10 % chance of a light frost occurring later.

The 50 % light-frost dates are April 7 in spring and November 9 in fall; a gardener can expect an even odds chance of a frost after the spring date and before the fall date. The 50 % hard-frost dates are March 19 in spring and November 20 in fall, marking the median point for 28 °F events.

A hard frost matters more than a light frost because the lower temperature can cause more severe damage to plant tissue.

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 25" 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 Sierra Vista Southeast, AZNumbered nearest stations: 1 — Tombstone, AZ — 28 mi; 2 — Benson, AZ — 37 mi; 3 — near Douglas, AZ — 39 mi; 4 — near Tubac, AZ — 49 mi; 5 — Sasabe, AZ — 77 mi.AZ25 mi · 40 km1. Tombstone, AZ — 28 mi12. Benson, AZ — 37 mi23. near Douglas, AZ — 39 mi34. near Tubac, AZ — 49 mi45. Sasabe, AZ — 77 mi5
  1. Tombstone, AZ 28 mi (44 km)
  2. Benson, AZ 37 mi (60 km)
  3. near Douglas, AZ 39 mi (63 km)
  4. near Tubac, AZ 49 mi (79 km)
  5. Sasabe, AZ 77 mi (123 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: 31.3456, -110.2542.