U.S. Frost Dates by Weather Station

NOAA station USC00422057 · Utah

Frost Dates near Midway, UT

NOAA weather station Deer Creek Dam (USC00422057), Utah · elevation 5270 ft (1606 m) · hardiness zone 6a*

Midway is the nearest town to the station (8.0 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter June 15only 1 spring in 10 still has a frost later
  • Typical last frostMay 2850% chance of a frost after it
  • Typical first fall frostSeptember 2350% chance of a frost before it
  • Frost-free season119 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Midway, UTSpring: a frost after May 11 in 9 years out of 10, after May 28 in half of the years, after June 15 in 1 year out of 10. Fall: the first frost comes before September 7 in 1 year out of 10, before September 23 in half of the years, before October 5 in 9 years out of 10. Typical frost-free season: 119 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 28First frost ~Sep 23Frost season near Midway, UTSpring: a frost after May 11 in 9 years out of 10, after May 28 in half of the years, after June 15 in 1 year out of 10. Fall: the first frost comes before September 7 in 1 year out of 10, before September 23 in half of the years, before October 5 in 9 years out of 10. Typical frost-free season: 119 days.JFMAMJJASONDLast frost ~May 28First frost ~Sep 23
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 15September 7
50% (typical)May 28September 23
90% (likely)May 11October 5
Frost-free season (32°F, 50% chance)
119 days
Hard frost (28°F), last in spring, 50% chance after
May 11
Hard frost (28°F), first in fall, 50% chance before
October 4

The last 15 years (2006–2020 normals)

Typical last frost May 25 (3 days earlier than the 30-year normal), typical first fall frost September 27 (4 days later). Frost-free season 124 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 near Midway: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 15, 20% June 8, 30% June 4, 40% May 31, 50% May 28, 60% May 24, 70% May 20, 80% May 16, 90% May 11. Observed last spring frost in recent years: 2021 May 27, 2022 June 1, 2023 May 9, 2024 May 26, 2025 May 22, 2026 May 23.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 15May 28May 112021: May 272022: June 12023: May 92024: May 262025: May 222026: May 23Fall near Midway: chance of a frost before this dateFall, chance of a frost before the date: 10% September 7, 20% September 13, 30% September 18, 40% September 21, 50% September 23, 60% September 26, 70% September 28, 80% October 1, 90% October 5. Observed first fall frost in recent years: 2021 September 21, 2022 October 11, 2023 September 23, 2024 October 19, 2025 October 7.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 7Sep 23Oct 52021: September 212022: October 112023: September 232024: October 192025: October 7
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 27September 21
2022June 1October 11
2023May 9September 23
2024May 26October 19
2025May 22October 7
2026May 23season not over yet

What these dates mean

The 119 days between the 32°F 50% dates in the Midway area frame the span in which light-frost risk shifts from unlikely to likely. The median, even-odds dates are May 28 for spring and September 23 for fall; a gardener can treat these as the pivot points for frost probability.

In spring, the cautious date for setting out tender crops is June 15, when there is only a 10 % chance of a light frost occurring later. Planting on May 11 carries a 90 % chance and is a gamble. In the fall, the cautious date to finish harvesting tender crops is September 7, with only a 10 % chance that a light frost has arrived earlier; waiting until October 5 would be a gamble with a 90 % chance of frost.

Hard frost at 28 °F (the 50% dates are May 11 and October 4) can damage plants more severely than a light 32 °F frost.

How to read the probabilities

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

  • Spring: "10% after June 15" 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 7" 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 Midway, UTNumbered nearest stations: 1 — Pleasant Grove, UT — 11 mi; 2 — near Provo, UT — 13 mi; 3 — Alta, UT — 14 mi; 4 — Cottonwood Weir, UT — 20 mi; 5 — Kamas, UT — 21 mi.WY25 mi · 40 km1. Pleasant Grove, UT — 11 mi12. near Provo, UT — 13 mi23. Alta, UT — 14 mi34. Cottonwood Weir, UT — 20 mi45. Kamas, UT — 21 mi5
  1. Pleasant Grove, UT 11 mi (18 km)
  2. near Provo, UT 13 mi (20 km)
  3. Alta, UT 14 mi (23 km)
  4. Cottonwood Weir, UT 20 mi (32 km)
  5. Kamas, UT 21 mi (34 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: 40.4044, -111.5289.