U.S. Frost Dates by Weather Station

NOAA station USC00053489 · Colorado

Frost Dates for Grand Junction, CO

NOAA weather station Grand Junction 6 ESE (USC00053489), Colorado · elevation 4760 ft (1451 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season179 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Grand Junction, COSpring: a frost after April 6 in 9 years out of 10, after April 23 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 179 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 20Frost season at Grand Junction, COSpring: a frost after April 6 in 9 years out of 10, after April 23 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 179 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 20
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 9October 5
50% (typical)April 23October 20
90% (likely)April 6November 5
Frost-free season (32°F, 50% chance)
179 days
Hard frost (28°F), last in spring, 50% chance after
April 8
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 24 (1 day later than the 30-year normal), typical first fall frost October 19 (1 day earlier). Frost-free season 177 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 Grand Junction: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 2, 30% April 29, 40% April 25, 50% April 23, 60% April 20, 70% April 16, 80% April 11, 90% April 6. Observed last spring frost in recent years: 2021 May 9, 2022 April 25, 2023 April 22, 2024 May 8, 2025 April 20, 2026 April 19.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 23Apr 62021: May 92022: April 252023: April 222024: May 82025: April 202026: April 19Fall at Grand Junction: chance of a frost before this dateFall, chance of a frost before the date: 10% October 5, 20% October 9, 30% October 14, 40% October 17, 50% October 20, 60% October 24, 70% October 27, 80% October 30, 90% November 5. Observed first fall frost in recent years: 2021 October 15, 2022 October 24, 2023 October 29, 2024 November 5, 2025 October 28.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 5Oct 20Nov 52021: October 152022: October 242023: October 292024: November 52025: October 28
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 15
2022April 25October 24
2023April 22October 29
2024May 8November 5
2025April 20October 28
2026April 19season not over yet

What these dates mean

Setting out tender crops on the early spring date of April 6 in Grand Junction is a gamble, as there is a 90 % chance of a light frost later that day. The 50 % date of April 23 marks the point at which the odds of a light frost are even, and the hard-frost 50 % date of April 8 indicates when a 28 °F freeze is as likely as not.

A cautious planting plan waits until the May 9 date, which carries only a 10 % chance of a light frost, and finishes tender crops by the cautious fall date of October 5, also a 10 % chance of an early frost. The gamble for late season work ends on November 5, when a 90 % chance of a light frost exists; the 50 % fall light-frost date is October 20 and the hard-frost 50 % date is November 1. Hard frost matters more than light frost because the lower 28 °F temperature can cause more severe plant injury.

How to read the probabilities

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

  • Spring: "10% after May 9" 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 5" 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 Grand Junction, CONumbered nearest stations: 1 — Grand Junction (Walker Field), CO — 7 mi; 2 — Palisade, CO — 8 mi; 3 — Altenbern, CO — 32 mi; 4 — Paonia, CO — 47 mi; 5 — Moab, UT — 66 mi.UT25 mi · 40 km1. Grand Junction (Walker Field), CO — 7 mi12. Palisade, CO — 8 mi23. Altenbern, CO — 32 mi34. Paonia, CO — 47 mi45. Moab, UT — 66 mi5
  1. Grand Junction (Walker Field), CO 7 mi (12 km)
  2. Palisade, CO 8 mi (13 km)
  3. Altenbern, CO 32 mi (51 km)
  4. Paonia, CO 47 mi (76 km)
  5. Moab, UT 66 mi (107 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 39.0422, -108.4664.