U.S. Frost Dates by Weather Station

NOAA station USC00427271 · Utah

Frost Dates for Richmond, UT

NOAA weather station Richmond (USC00427271), Utah · elevation 4680 ft (1427 m) · hardiness zone 6a*

  • Lower-risk planting dateafter June 2only 1 spring in 10 still has a frost later
  • Typical last frostMay 1150% chance of a frost after it
  • Typical first fall frostOctober 550% chance of a frost before it
  • Frost-free season143 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Richmond, UTSpring: a frost after April 27 in 9 years out of 10, after May 11 in half of the years, after June 2 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 5 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 143 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 11First frost ~Oct 5Frost season at Richmond, UTSpring: a frost after April 27 in 9 years out of 10, after May 11 in half of the years, after June 2 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 5 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 143 days.JFMAMJJASONDLast frost ~May 11First frost ~Oct 5
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)June 2September 21
50% (typical)May 11October 5
90% (likely)April 27October 20
Frost-free season (32°F, 50% chance)
143 days
Hard frost (28°F), last in spring, 50% chance after
April 26
Hard frost (28°F), first in fall, 50% chance before
October 17

The last 15 years (2006–2020 normals)

Typical last frost May 11 (same as the 30-year normal), typical first fall frost October 6 (1 day later). Frost-free season 146 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 Richmond: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 2, 20% May 25, 30% May 20, 40% May 15, 50% May 11, 60% May 8, 70% May 5, 80% May 2, 90% April 27. Observed last spring frost in recent years: 2021 May 9, 2022 June 1, 2023 April 25, 2024 May 24, 2025 April 19, 2026 May 19.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 2May 11Apr 272021: May 92022: June 12023: April 252024: May 242025: April 192026: May 19Fall at Richmond: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 26, 30% September 30, 40% October 2, 50% October 5, 60% October 7, 70% October 11, 80% October 15, 90% October 20. Observed first fall frost in recent years: 2021 October 12, 2022 October 22, 2023 October 13, 2024 October 19, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 21Oct 5Oct 202021: October 122022: October 222023: October 132024: October 192025: October 13
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 9October 12
2022June 1October 22
2023April 25October 13
2024May 24October 19
2025April 19October 13
2026May 19season not over yet

What these dates mean

Planting tender crops on April 27 carries a 90 % chance that a light frost will still occur later, making that early date a gamble for Richmond gardeners. The median point for light-frost risk in spring is May 11, when the odds of a frost later are exactly fifty-fifty; it is not itself a frost date.

A cautious schedule therefore uses the June 2 date, which has only a ten-percent chance of a later frost, to set out tender crops, and the September 21 date, which has a ten-percent chance of an earlier frost, to finish harvesting them. The fall median light-frost date is October 5, marking even odds of a frost arriving before that day.

Hard frost at 28 °F, whose 50 % dates are April 26 and October 17, can damage plants more severely than a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after June 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 September 21" 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 Richmond, UTNumbered nearest stations: 1 — near Logan, UT — 11 mi; 2 — Logan Radio Kvnu, UT — 12 mi; 3 — Preston, ID — 13 mi; 4 — near Garland, UT — 14 mi; 5 — Laketown, UT — 26 mi.IDWY25 mi · 40 km1. near Logan, UT — 11 mi12. Logan Radio Kvnu, UT — 12 mi23. Preston, ID — 13 mi34. near Garland, UT — 14 mi45. Laketown, UT — 26 mi5
  1. near Logan, UT 11 mi (18 km)
  2. Logan Radio Kvnu, UT 12 mi (19 km)
  3. Preston, ID 13 mi (22 km)
  4. near Garland, UT 14 mi (22 km)
  5. Laketown, UT 26 mi (42 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: 41.9064, -111.81.