U.S. Frost Dates by Weather Station

NOAA station USC00020750 · Arizona

Frost Dates for Betatakin, AZ

NOAA weather station Betatakin (USC00020750), Arizona · elevation 7286 ft (2221 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 26only 1 spring in 10 still has a frost later
  • Typical last frostMay 750% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season159 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Betatakin, AZSpring: a frost after April 23 in 9 years out of 10, after May 7 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 15 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 159 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 7First frost ~Oct 15Frost season at Betatakin, AZSpring: a frost after April 23 in 9 years out of 10, after May 7 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 15 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 159 days.JFMAMJJASONDLast frost ~May 7First frost ~Oct 15
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.Today

Frost dates (32°F)

Probability of frost, based on 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 26September 30
50% (typical)May 7October 15
90% (likely)April 23November 1
Frost-free season (32°F, 50% chance)
159 days
Hard frost (28°F), last in spring, 50% chance after
April 28
Hard frost (28°F), first in fall, 50% chance before
October 27

The last 15 years (2006–2020 normals)

Typical last frost May 11 (4 days later than the 30-year normal), typical first fall frost October 14 (1 day earlier). Frost-free season 157 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 Betatakin: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 26, 20% May 20, 30% May 14, 40% May 10, 50% May 7, 60% May 4, 70% May 1, 80% April 28, 90% April 23. Observed last spring frost in recent years: 2021 May 23, 2022 May 4, 2023 May 6, 2024 May 8, 2025 April 27, 2026 May 19.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 26May 7Apr 232021: May 232022: May 42023: May 62024: May 82025: April 272026: May 19Fall at Betatakin: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 4, 30% October 8, 40% October 12, 50% October 15, 60% October 18, 70% October 23, 80% October 27, 90% November 1. Observed first fall frost in recent years: 2021 October 12, 2022 October 23, 2023 October 12, 2024 October 19.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 15Nov 12021: October 122022: October 232023: October 122024: October 19
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
2021May 23October 12
2022May 4October 23
2023May 6October 12
2024May 8October 19
2025April 27incomplete record
2026May 19season not over yet

What these dates mean

May 26 is the cautious spring date for Betatakin; it gives a gardener a 10% chance of a light frost later, so tender crops can be set out with relatively low risk. The 50% date is May 7, meaning there is an even chance of a light frost after that point. In the fall the cautious date is September 30, offering a 10% chance that a light frost will have arrived earlier, which guides the latest time to finish harvesting tender crops. The 50% date is October 15, indicating a 50-50 chance of a light frost.

Hard frosts are recorded at 28 °F; the median hard-frost date is April 28 in spring and October 27 in fall. A hard frost can damage plants that would survive a light frost, making it a more critical threshold for garden planning.

How to read the probabilities

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

  • Spring: "10% after May 26" 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 September 30" 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 Betatakin, AZNumbered nearest stations: 1 — Canyon De Chelly, AZ — 66 mi; 2 — Bluff, UT — 69 mi; 3 — Natural Bridges National Monument, UT — 71 mi; 4 — Blanding, UT — 87 mi; 5 — Wupatki National Monument, AZ — 92 mi.AZUTNMCO50 mi · 80 km1. Canyon De Chelly, AZ — 66 mi12. Bluff, UT — 69 mi23. Natural Bridges National Monument, UT — 71 mi34. Blanding, UT — 87 mi45. Wupatki National Monument, AZ — 92 mi5
  1. Canyon De Chelly, AZ 66 mi (107 km)
  2. Bluff, UT 69 mi (110 km)
  3. Natural Bridges National Monument, UT 71 mi (115 km)
  4. Blanding, UT 87 mi (140 km)
  5. Wupatki National Monument, AZ 92 mi (148 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 36.6778, -110.5411.