U.S. Frost Dates by Weather Station

NOAA station USC00422253 · Utah

Frost Dates for Duchesne, UT

NOAA weather station Duchesne (USC00422253), Utah · elevation 5551 ft (1692 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 26only 1 spring in 10 still has a frost later
  • Typical last frostMay 650% chance of a frost after it
  • Typical first fall frostOctober 550% chance of a frost before it
  • Frost-free season150 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Duchesne, UTSpring: a frost after April 22 in 9 years out of 10, after May 6 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 5 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 150 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 6First frost ~Oct 5Frost season at Duchesne, UTSpring: a frost after April 22 in 9 years out of 10, after May 6 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 5 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 150 days.JFMAMJJASONDLast frost ~May 6First frost ~Oct 5
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 26September 24
50% (typical)May 6October 5
90% (likely)April 22October 18
Frost-free season (32°F, 50% chance)
150 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 16

The last 15 years (2006–2020 normals)

Typical last frost May 9 (3 days later than the 30-year normal), typical first fall frost October 6 (1 day later). Frost-free season 149 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 Duchesne: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 26, 20% May 18, 30% May 13, 40% May 10, 50% May 6, 60% May 3, 70% April 30, 80% April 27, 90% April 22. Observed last spring frost in recent years: 2021 April 24, 2022 May 21, 2023 April 29, 2024 May 24, 2026 May 7.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 26May 6Apr 222021: April 242022: May 212023: April 292024: May 242026: May 7Fall at Duchesne: chance of a frost before this dateFall, chance of a frost before the date: 10% September 24, 20% September 28, 30% October 1, 40% October 3, 50% October 5, 60% October 7, 70% October 11, 80% October 14, 90% October 18. Observed first fall frost in recent years: 2021 October 15, 2022 October 14, 2023 September 23, 2024 October 19, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 24Oct 5Oct 182021: October 152022: October 142023: September 232024: October 192025: October 13
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 24October 15
2022May 21October 14
2023April 29September 23
2024May 24October 19
2025incomplete recordOctober 13
2026May 7season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Duchesne is September 24, when there is only a 10 % chance that a light frost has arrived. The 50% date for light frost is October 5, indicating even odds of a frost on that day, while October 18 carries a 90 % chance of a frost and is a gamble for tender crops. Hard frost (28 °F) can damage plant tissue more severely than a light frost (32 °F).

In spring, the cautious date for setting out tender crops is May 26, with a 10 % chance of a light frost later. The 50% light-frost date is May 6, and April 22 carries a 90 % chance of a frost and is a gamble. The hard-frost 50% date is April 22, marking even odds for a hard freeze. The 50% dates give a clear midpoint for risk assessment.

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 24" 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 Duchesne, UTNumbered nearest stations: 1 — near Roosevelt, UT — 25 mi; 2 — Neola, UT — 25 mi; 3 — Ouray, UT — 40 mi; 4 — Scofield-Skyline Mine, UT — 54 mi; 5 — Kamas, UT — 57 mi.25 mi · 40 km1. near Roosevelt, UT — 25 mi12. Neola, UT — 25 mi23. Ouray, UT — 40 mi34. Scofield-Skyline Mine, UT — 54 mi45. Kamas, UT — 57 mi5
  1. near Roosevelt, UT 25 mi (40 km)
  2. Neola, UT 25 mi (40 km)
  3. Ouray, UT 40 mi (64 km)
  4. Scofield-Skyline Mine, UT 54 mi (88 km)
  5. Kamas, UT 57 mi (92 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.1703, -110.3978.