U.S. Frost Dates by Weather Station

NOAA station USC00053261 · Colorado

Frost Dates for Georgetown, CO

NOAA weather station Georgetown (USC00053261), Colorado · elevation 8520 ft (2597 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 14only 1 spring in 10 still has a frost later
  • Typical last frostMay 3050% chance of a frost after it
  • Typical first fall frostSeptember 1950% chance of a frost before it
  • Frost-free season112 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Georgetown, COSpring: a frost after May 17 in 9 years out of 10, after May 30 in half of the years, after June 14 in 1 year out of 10. Fall: the first frost comes before September 5 in 1 year out of 10, before September 19 in half of the years, before September 30 in 9 years out of 10. Typical frost-free season: 112 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 30First frost ~Sep 19Frost season at Georgetown, COSpring: a frost after May 17 in 9 years out of 10, after May 30 in half of the years, after June 14 in 1 year out of 10. Fall: the first frost comes before September 5 in 1 year out of 10, before September 19 in half of the years, before September 30 in 9 years out of 10. Typical frost-free season: 112 days.JFMAMJJASONDLast frost ~May 30First frost ~Sep 19
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 14September 5
50% (typical)May 30September 19
90% (likely)May 17September 30
Frost-free season (32°F, 50% chance)
112 days
Hard frost (28°F), last in spring, 50% chance after
May 15
Hard frost (28°F), first in fall, 50% chance before
September 30

The last 15 years (2006–2020 normals)

Typical last frost May 30 (same as the 30-year normal), typical first fall frost September 21 (2 days later). Frost-free season 112 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 Georgetown: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 14, 20% June 9, 30% June 5, 40% June 2, 50% May 30, 60% May 28, 70% May 25, 80% May 21, 90% May 17. Observed last spring frost in recent years: 2021 May 25, 2022 June 2, 2023 May 9, 2024 May 22, 2025 May 22, 2026 May 23.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jun 14May 30May 172021: May 252022: June 22023: May 92024: May 222025: May 222026: May 23Fall at Georgetown: chance of a frost before this dateFall, chance of a frost before the date: 10% September 5, 20% September 11, 30% September 14, 40% September 17, 50% September 19, 60% September 22, 70% September 24, 80% September 27, 90% September 30. Observed first fall frost in recent years: 2021 September 21, 2022 September 11, 2023 October 3, 2024 October 18, 2025 September 17.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 5Sep 19Sep 302021: September 212022: September 112023: October 32024: October 182025: September 17
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 25September 21
2022June 2September 11
2023May 9October 3
2024May 22October 18
2025May 22September 17
2026May 23season not over yet

What these dates mean

Setting out tender crops on the early spring date, May 17, is a gamble because it carries a 90% chance of a frost later in the season. In Georgetown this high risk reflects the historic pattern recorded over 27 years.

The 50% light-frost date in spring is May 30; there is a 50% chance of a frost later than this date. In fall the 50% light-frost date is September 19, with a 50% chance of a frost earlier than this date. The median hard-frost dates are May 15 for spring and September 30 for fall.

For a cautious plan, tender crops are usually set out after the June 14 spring date, which has only a 10% chance of a later frost, and harvested before the September 5 fall date, which has only a 10% chance of an earlier frost. A hard frost at 28 °F 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 14" 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 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 Georgetown, CONumbered nearest stations: 1 — Cabin Creek, CO — 3 mi; 2 — Grant, CO — 17 mi; 3 — Evergreen, CO — 21 mi; 4 — near Coal Creek, CO — 21 mi; 5 — Bailey, CO — 24 mi.25 mi · 40 km1. Cabin Creek, CO — 3 mi12. Grant, CO — 17 mi23. Evergreen, CO — 21 mi34. near Coal Creek, CO — 21 mi45. Bailey, CO — 24 mi5
  1. Cabin Creek, CO 3 mi (6 km)
  2. Grant, CO 17 mi (27 km)
  3. Evergreen, CO 21 mi (34 km)
  4. near Coal Creek, CO 21 mi (34 km)
  5. Bailey, CO 24 mi (38 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 39.7053, -105.6997.