U.S. Frost Dates by Weather Station

NOAA station USC00422101 · Utah

Frost Dates for Deseret, UT

NOAA weather station Deseret (USC00422101), Utah · elevation 4590 ft (1399 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 31only 1 spring in 10 still has a frost later
  • Typical last frostMay 1450% chance of a frost after it
  • Typical first fall frostSeptember 3050% chance of a frost before it
  • Frost-free season137 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Deseret, UTSpring: a frost after April 29 in 9 years out of 10, after May 14 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 16 in 1 year out of 10, before September 30 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 137 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 14First frost ~Sep 30Frost season at Deseret, UTSpring: a frost after April 29 in 9 years out of 10, after May 14 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 16 in 1 year out of 10, before September 30 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 137 days.JFMAMJJASONDLast frost ~May 14First frost ~Sep 30
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 31September 16
50% (typical)May 14September 30
90% (likely)April 29October 14
Frost-free season (32°F, 50% chance)
137 days
Hard frost (28°F), last in spring, 50% chance after
May 1
Hard frost (28°F), first in fall, 50% chance before
October 10

The last 15 years (2006–2020 normals)

Typical last frost May 15 (1 day later than the 30-year normal), typical first fall frost October 2 (2 days later). Frost-free season 141 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 Deseret: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 31, 20% May 25, 30% May 20, 40% May 17, 50% May 14, 60% May 10, 70% May 7, 80% May 3, 90% April 29. Observed last spring frost in recent years: 2021 May 24, 2022 May 24, 2023 May 9, 2024 May 22, 2025 May 20, 2026 May 20.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 31May 14Apr 292021: May 242022: May 242023: May 92024: May 222025: May 202026: May 20Fall at Deseret: chance of a frost before this dateFall, chance of a frost before the date: 10% September 16, 20% September 22, 30% September 25, 40% September 28, 50% September 30, 60% October 2, 70% October 5, 80% October 9, 90% October 14. Observed first fall frost in recent years: 2021 September 21, 2022 October 14, 2023 October 13, 2024 October 19, 2025 October 6.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 16Sep 30Oct 142021: September 212022: October 142023: October 132024: October 192025: October 6
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 24September 21
2022May 24October 14
2023May 9October 13
2024May 22October 19
2025May 20October 6
2026May 20season not over yet

What these dates mean

Setting out tender crops on April 29 in Deseret carries a 90 % chance of a light frost later, so it is a gamble. The cautious spring option is May 31, when only a 10 % chance of a later frost remains. In the fall, the gamble begins at October 14 with a 90 % chance that a light frost has already arrived, while the cautious finish date is September 16, offering only a 10 % chance of an earlier frost.

The 50 % light-frost date is May 14 in spring and September 30 in fall; a gardener has equal odds of a frost occurring on either side of each of those days. The median hard-frost dates are May 1 and October 10; a hard frost at 28 °F can damage plants that survive a light frost at 32 °F, making it a more serious threat.

How to read the probabilities

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

  • Spring: "10% after May 31" 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 16" 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 Deseret, UTNumbered nearest stations: 1 — Black Rock, UT — 43 mi; 2 — near Richfield, UT — 48 mi; 3 — Nephi, UT — 53 mi; 4 — Manti, UT — 55 mi; 5 — Ephraim, UT — 56 mi.UT25 mi · 40 km1. Black Rock, UT — 43 mi12. near Richfield, UT — 48 mi23. Nephi, UT — 53 mi34. Manti, UT — 55 mi45. Ephraim, UT — 56 mi5
  1. Black Rock, UT 43 mi (70 km)
  2. near Richfield, UT 48 mi (77 km)
  3. Nephi, UT 53 mi (85 km)
  4. Manti, UT 55 mi (88 km)
  5. Ephraim, UT 56 mi (91 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: 39.2872, -112.6519.