U.S. Frost Dates by Weather Station

NOAA station USW00093010 · Colorado

Frost Dates near Limon, CO

NOAA weather station Limon WSMO (USW00093010), Colorado · elevation 5364 ft (1635 m) · hardiness zone 5b*

Limon is the nearest town to the station (5.3 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 4only 1 spring in 10 still has a frost later
  • Typical last frostMay 2150% chance of a frost after it
  • Typical first fall frostSeptember 2650% chance of a frost before it
  • Frost-free season127 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season near Limon, COSpring: a frost after May 7 in 9 years out of 10, after May 21 in half of the years, after June 4 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before September 26 in half of the years, before October 6 in 9 years out of 10. Typical frost-free season: 127 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 21First frost ~Sep 26Frost season near Limon, COSpring: a frost after May 7 in 9 years out of 10, after May 21 in half of the years, after June 4 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before September 26 in half of the years, before October 6 in 9 years out of 10. Typical frost-free season: 127 days.JFMAMJJASONDLast frost ~May 21First frost ~Sep 26
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 4September 14
50% (typical)May 21September 26
90% (likely)May 7October 6
Frost-free season (32°F, 50% chance)
127 days
Hard frost (28°F), last in spring, 50% chance after
May 9
Hard frost (28°F), first in fall, 50% chance before
October 3

The last 15 years (2006–2020 normals)

Typical last frost May 20 (1 day earlier than the 30-year normal), typical first fall frost September 30 (4 days later). Frost-free season 130 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 Limon: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 4, 20% May 31, 30% May 27, 40% May 24, 50% May 21, 60% May 18, 70% May 14, 80% May 11, 90% May 7. Observed last spring frost in recent years: 2021 May 11, 2022 May 21, 2023 May 1, 2024 May 22, 2025 May 22, 2026 May 7.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 4May 21May 72021: May 112022: May 212023: May 12024: May 222025: May 222026: May 7Fall near Limon: chance of a frost before this dateFall, chance of a frost before the date: 10% September 14, 20% September 18, 30% September 21, 40% September 24, 50% September 26, 60% September 28, 70% October 1, 80% October 3, 90% October 6. Observed first fall frost in recent years: 2021 September 22, 2022 October 6, 2023 September 24, 2025 October 17.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 14Sep 26Oct 62021: September 222022: October 62023: September 242025: October 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 11September 22
2022May 21October 6
2023May 1September 24
2024May 22incomplete record
2025May 22October 17
2026May 7season not over yet

What these dates mean

The 127 days between the 32°F 50% dates, May 21 and September 26, frame the period when tender crops can be grown in the Limon area. The 50% dates are points of even odds for a light frost but are not frost dates themselves; they simply mark the middle of the historical range.

June 4, the cautious spring date with a 10 % chance of a later frost, is the reference for setting out tender crops, while May 7 carries a 90 % chance and is a gamble. In fall, September 14 is the cautious date with a 10 % chance of an earlier frost, and October 6 carries a 90 % chance and is a gamble. The 50% hard-frost dates are May 9 in spring and October 3 in fall. A hard frost at 28 °F can damage plants that would survive 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 4" 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 14" 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 Limon, CONumbered nearest stations: 1 — Hugo, CO — 13 mi; 2 — Byers, CO — 44 mi; 3 — Colorado Springs, CO — 58 mi; 4 — Tacony, CO — 61 mi; 5 — Joes, CO — 64 mi.CO25 mi · 40 km1. Hugo, CO — 13 mi12. Byers, CO — 44 mi23. Colorado Springs, CO — 58 mi34. Tacony, CO — 61 mi45. Joes, CO — 64 mi5
  1. Hugo, CO 13 mi (20 km)
  2. Byers, CO 44 mi (71 km)
  3. Colorado Springs, CO 58 mi (94 km)
  4. Tacony, CO 61 mi (99 km)
  5. Joes, CO 64 mi (103 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: 39.1894, -103.7158.