U.S. Frost Dates by Weather Station

NOAA station USC00427686 · Utah

Frost Dates near Santaquin, UT

NOAA weather station Santaquin Chlorinator (USC00427686), Utah · elevation 5160 ft (1573 m) · hardiness zone 6b*

Santaquin is the nearest town to the station (1.2 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 May 28only 1 spring in 10 still has a frost later
  • Typical last frostMay 450% chance of a frost after it
  • Typical first fall frostOctober 1150% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season near Santaquin, UTSpring: a frost after April 18 in 9 years out of 10, after May 4 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 11 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 4First frost ~Oct 11Frost season near Santaquin, UTSpring: a frost after April 18 in 9 years out of 10, after May 4 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 11 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~May 4First frost ~Oct 11
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 28September 27
50% (typical)May 4October 11
90% (likely)April 18October 26
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 19
Hard frost (28°F), first in fall, 50% chance before
October 23

The last 15 years (2006–2020 normals)

Typical last frost May 8 (4 days later than the 30-year normal), typical first fall frost October 11. Frost-free season 156 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 Santaquin: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 28, 20% May 19, 30% May 14, 40% May 8, 50% May 4, 60% May 1, 70% April 28, 80% April 24, 90% April 18. Observed last spring frost in recent years: 2021 May 22, 2022 May 21, 2023 April 26, 2024 May 9, 2025 April 20, 2026 May 18.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 28May 4Apr 182021: May 222022: May 212023: April 262024: May 92025: April 202026: May 18Fall near Santaquin: chance of a frost before this dateFall, chance of a frost before the date: 10% September 27, 20% October 1, 30% October 5, 40% October 8, 50% October 11, 60% October 14, 70% October 17, 80% October 21, 90% October 26. Observed first fall frost in recent years: 2021 October 13, 2022 October 23, 2023 October 26, 2024 October 25, 2025 October 21.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 27Oct 11Oct 262021: October 132022: October 232023: October 262024: October 252025: October 21
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 22October 13
2022May 21October 23
2023April 26October 26
2024May 9October 25
2025April 20October 21
2026May 18season not over yet

What these dates mean

The cautious fall date in the Santaquin area for finishing the harvest is September 27, when there is only a 10 % chance that a light frost has arrived earlier. This date signals the point at which a gardener can most reliably expect to complete tender-crop harvesting before frost becomes likely.

The 50 % light-frost dates are May 4 in spring and October 11 in fall; each marks the median point where a 32 °F frost is equally likely to occur later or earlier. The 50 % hard-frost dates are April 19 and October 23, representing the midpoint of the recorded risk for a 28 °F frost.

For a cautious planting schedule, tender crops should be set out after the spring cautious date of May 28, which carries only a 10 % chance of a light frost later, and should be harvested before the fall cautious date of September 27, which carries only a 10 % chance of a light frost earlier. Hard frost at 28 °F can harm plants that survive a light frost at 32 °F, making it a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 28" 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 27" 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 Santaquin, UTNumbered nearest stations: 1 — Spanish Fork, UT — 13 mi; 2 — Nephi, UT — 17 mi; 3 — near Provo, UT — 21 mi; 4 — Pleasant Grove, UT — 28 mi; 5 — near Midway, UT — 34 mi.25 mi · 40 km1. Spanish Fork, UT — 13 mi12. Nephi, UT — 17 mi23. near Provo, UT — 21 mi34. Pleasant Grove, UT — 28 mi45. near Midway, UT — 34 mi5
  1. Spanish Fork, UT 13 mi (20 km)
  2. Nephi, UT 17 mi (28 km)
  3. near Provo, UT 21 mi (34 km)
  4. Pleasant Grove, UT 28 mi (46 km)
  5. near Midway, UT 34 mi (54 km)

Sources

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

Station coordinates: 39.9578, -111.7794.