U.S. Frost Dates by Weather Station

NOAA station USC00424342 · Utah

Frost Dates for Jensen, UT

NOAA weather station Jensen (USC00424342), Utah · elevation 4736 ft (1444 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 5only 1 spring in 10 still has a frost later
  • Typical last frostMay 2050% chance of a frost after it
  • Typical first fall frostSeptember 2550% chance of a frost before it
  • Frost-free season126 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Jensen, UTSpring: a frost after May 5 in 9 years out of 10, after May 20 in half of the years, after June 5 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 25 in half of the years, before October 5 in 9 years out of 10. Typical frost-free season: 126 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 20First frost ~Sep 25Frost season at Jensen, UTSpring: a frost after May 5 in 9 years out of 10, after May 20 in half of the years, after June 5 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 25 in half of the years, before October 5 in 9 years out of 10. Typical frost-free season: 126 days.JFMAMJJASONDLast frost ~May 20First frost ~Sep 25
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 5September 11
50% (typical)May 20September 25
90% (likely)May 5October 5
Frost-free season (32°F, 50% chance)
126 days
Hard frost (28°F), last in spring, 50% chance after
May 6
Hard frost (28°F), first in fall, 50% chance before
October 3

The last 15 years (2006–2020 normals)

Typical last frost May 19 (1 day earlier than the 30-year normal), typical first fall frost September 28 (3 days later). Frost-free season 129 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 Jensen: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 5, 20% May 31, 30% May 27, 40% May 24, 50% May 20, 60% May 18, 70% May 14, 80% May 10, 90% May 5. Observed last spring frost in recent years: 2022 May 22, 2023 May 3, 2025 April 22, 2026 May 20.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 5May 20May 52022: May 222023: May 32025: April 222026: May 20Fall at Jensen: chance of a frost before this dateFall, chance of a frost before the date: 10% September 11, 20% September 15, 30% September 19, 40% September 22, 50% September 25, 60% September 27, 70% September 29, 80% October 1, 90% October 5. Observed first fall frost in recent years: 2021 October 13, 2022 October 14, 2023 September 24, 2024 October 20, 2025 October 8.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 11Sep 25Oct 52021: October 132022: October 142023: September 242024: October 202025: October 8
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
2021incomplete recordOctober 13
2022May 22October 14
2023May 3September 24
2024incomplete recordOctober 20
2025April 22October 8
2026May 20season not over yet

What these dates mean

The 126 days between the 50% dates—May 20 and September 25—define the period in Jensen when the chance of a light frost is less than fifty percent, giving a basic window for planting and harvesting. The 50% date is May 20 and the 50% date is September 25; they are not frost dates themselves.

For tender crops the cautious spring date is June 5, when there is only a ten-percent chance of a frost later, while the earlier May 5 date carries a ninety-percent chance and is a gamble. In the fall the cautious date to finish harvesting tender crops is September 11, with a ten-percent chance of a frost earlier, and the later October 5 date has a ninety-percent chance and is risky.

The 50% hard-frost dates are May 6 and October 3; a hard frost at 28 °F can damage plant tissue more severely than a light frost at 32 °F, so it matters more for garden survival.

How to read the probabilities

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

  • Spring: "10% after June 5" 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 11" 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 Jensen, UTNumbered nearest stations: 1 — Ouray, UT — 22 mi; 2 — near Roosevelt, UT — 33 mi; 3 — Rangely, CO — 36 mi; 4 — Neola, UT — 37 mi; 5 — Flaming Gorge, UT — 40 mi.COWY25 mi · 40 km1. Ouray, UT — 22 mi12. near Roosevelt, UT — 33 mi23. Rangely, CO — 36 mi34. Neola, UT — 37 mi45. Flaming Gorge, UT — 40 mi5
  1. Ouray, UT 22 mi (36 km)
  2. near Roosevelt, UT 33 mi (53 km)
  3. Rangely, CO 36 mi (57 km)
  4. Neola, UT 37 mi (60 km)
  5. Flaming Gorge, UT 40 mi (64 km)

Sources

* Hardiness zone 5a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.3611, -109.3464.