U.S. Frost Dates by Weather Station

NOAA station USC00423600 · Utah

Frost Dates for Hans Flat Ranger Station, UT

NOAA weather station Hans Flat Ranger Station (USC00423600), Utah · elevation 6600 ft (2012 m) · hardiness zone 7b*

  • Lower-risk planting dateafter May 24only 1 spring in 10 still has a frost later
  • Typical last frostMay 150% chance of a frost after it
  • Typical first fall frostOctober 1650% chance of a frost before it
  • Frost-free season163 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Hans Flat Ranger Station, UTSpring: a frost after April 18 in 9 years out of 10, after May 1 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 16 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 163 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 1First frost ~Oct 16Frost season at Hans Flat Ranger Station, UTSpring: a frost after April 18 in 9 years out of 10, after May 1 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 16 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 163 days.JFMAMJJASONDLast frost ~May 1First frost ~Oct 16
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 24October 2
50% (typical)May 1October 16
90% (likely)April 18November 1
Frost-free season (32°F, 50% chance)
163 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 26

The last 15 years (2006–2020 normals)

Typical last frost May 4 (3 days later than the 30-year normal), typical first fall frost October 15 (1 day earlier). Frost-free season 163 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 Hans Flat Ranger Station: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 24, 20% May 14, 30% May 9, 40% May 5, 50% May 1, 60% April 30, 70% April 26, 80% April 23, 90% April 18. Observed last spring frost in recent years: 2021 April 29, 2022 May 4, 2023 April 26, 2024 May 9, 2025 April 20, 2026 April 18.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 24May 1Apr 182021: April 292022: May 42023: April 262024: May 92025: April 202026: April 18Fall at Hans Flat Ranger Station: chance of a frost before this dateFall, chance of a frost before the date: 10% October 2, 20% October 5, 30% October 9, 40% October 12, 50% October 16, 60% October 19, 70% October 23, 80% October 27, 90% November 1. Observed first fall frost in recent years: 2021 October 13, 2022 October 23, 2023 October 29, 2024 October 30, 2025 October 28.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 2Oct 16Nov 12021: October 132022: October 232023: October 292024: October 302025: October 28
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
2021April 29October 13
2022May 4October 23
2023April 26October 29
2024May 9October 30
2025April 20October 28
2026April 18season not over yet

What these dates mean

May 24 is the cautious spring date for light frost (32 °F) at Hans Flat Ranger Station, and it marks the point when there is only a 10 % chance of a later frost, allowing a gardener to set out tender crops. The 50% date, May 1, indicates an even-odds chance of a later frost, so a gardener should expect roughly equal possibility of frost after that day. The median hard-frost date in spring is April 22.

October 2 is the cautious fall date for light frost, with only a 10 % chance that a frost has already arrived, making it the deadline to finish harvesting tender crops. The 50% date, October 16, signals an even-odds chance of a frost earlier, giving a balanced reference point for planning. The median hard-frost date in fall is October 26. A hard frost at 28 °F can damage plant tissue that survives a light frost, so it is a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 24" 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 2" 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 Hans Flat Ranger Station, UTNumbered nearest stations: 1 — Canyonlands-The Needles, UT — 24 mi; 2 — Canyonlands-The Neck, UT — 24 mi; 3 — Moab, UT — 41 mi; 4 — Natural Bridges National Monument, UT — 46 mi; 5 — Blanding, UT — 58 mi.UTCO25 mi · 40 km1. Canyonlands-The Needles, UT — 24 mi12. Canyonlands-The Neck, UT — 24 mi23. Moab, UT — 41 mi34. Natural Bridges National Monument, UT — 46 mi45. Blanding, UT — 58 mi5
  1. Canyonlands-The Needles, UT 24 mi (38 km)
  2. Canyonlands-The Neck, UT 24 mi (39 km)
  3. Moab, UT 41 mi (66 km)
  4. Natural Bridges National Monument, UT 46 mi (74 km)
  5. Blanding, UT 58 mi (94 km)

Sources

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

Station coordinates: 38.2553, -110.18.