U.S. Frost Dates by Weather Station

NOAA station USC00429717 · Utah

Frost Dates for Zion National Park, UT

NOAA weather station Zion National Park (USC00429717), Utah · elevation 4038 ft (1231 m) · hardiness zone 7b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1350% chance of a frost after it
  • Typical first fall frostNovember 250% chance of a frost before it
  • Frost-free season202 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Zion National Park, UTSpring: a frost after March 22 in 9 years out of 10, after April 13 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 20 in 1 year out of 10, before November 2 in half of the years, before November 17 in 9 years out of 10. Typical frost-free season: 202 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 13First frost ~Nov 2Frost season at Zion National Park, UTSpring: a frost after March 22 in 9 years out of 10, after April 13 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 20 in 1 year out of 10, before November 2 in half of the years, before November 17 in 9 years out of 10. Typical frost-free season: 202 days.JFMAMJJASONDLast frost ~Apr 13First frost ~Nov 2
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 2October 20
50% (typical)April 13November 2
90% (likely)March 22November 17
Frost-free season (32°F, 50% chance)
202 days
Hard frost (28°F), last in spring, 50% chance after
March 23
Hard frost (28°F), first in fall, 50% chance before
November 12

The last 15 years (2006–2020 normals)

Typical last frost April 11 (2 days earlier than the 30-year normal), typical first fall frost November 2. Frost-free season 202 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 Zion National Park: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 26, 30% April 21, 40% April 17, 50% April 13, 60% April 8, 70% April 4, 80% March 31, 90% March 22. Observed last spring frost in recent years: 2022 April 25, 2023 April 8, 2024 March 27, 2025 April 21, 2026 March 7.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1May 2Apr 13Mar 222022: April 252023: April 82024: March 272025: April 212026: March 7Fall at Zion National Park: chance of a frost before this dateFall, chance of a frost before the date: 10% October 20, 20% October 24, 30% October 28, 40% October 30, 50% November 2, 60% November 5, 70% November 8, 80% November 12, 90% November 17. Observed first fall frost in recent years: 2022 October 24, 2023 October 29, 2024 October 30, 2025 December 1.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 20Nov 2Nov 172022: October 242023: October 292024: October 302025: December 1
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 recordincomplete record
2022April 25October 24
2023April 8October 29
2024March 27October 30
2025April 21December 1
2026March 7season not over yet

What these dates mean

Setting tender crops on the early spring date, March 22, carries a 90 % chance of a light frost and is therefore a gamble for Zion National Park gardeners.

The 50 % hard-frost point is March 23 in spring and November 12 in fall; at each point the likelihood of a hard frost reaches 50 %. The cautious spring date for tender crops is May 2, when only a 10 % chance of a light frost remains, while the cautious fall date to finish harvesting tender crops is October 20, also with a 10 % chance of an earlier light frost.

A hard frost at 28 °F can damage plants that survive a light frost at 32 °F, so it represents a higher risk for tender crops in this location.

How to read the probabilities

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

  • Spring: "10% after May 2" 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 20" 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 Zion National Park, UTNumbered nearest stations: 1 — New Harmony, UT — 24 mi; 2 — Pipe Spring National Monument, AZ — 27 mi; 3 — Kanab, UT — 28 mi; 4 — Alton, UT — 32 mi; 5 — Bryce Canyon National Park Headquarters, UT — 54 mi.UTNV25 mi · 40 km1. New Harmony, UT — 24 mi12. Pipe Spring National Monument, AZ — 27 mi23. Kanab, UT — 28 mi34. Alton, UT — 32 mi45. Bryce Canyon National Park Headquarters, UT — 54 mi5
  1. New Harmony, UT 24 mi (39 km)
  2. Pipe Spring National Monument, AZ 27 mi (44 km)
  3. Kanab, UT 28 mi (44 km)
  4. Alton, UT 32 mi (51 km)
  5. Bryce Canyon National Park Headquarters, UT 54 mi (86 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: 37.2092, -112.9814.