U.S. Frost Dates by Weather Station

NOAA station USC00054546 · Colorado

Frost Dates for Kim 10 SSE, CO

NOAA weather station Kim 10 SSE (USC00054546), Colorado · elevation 5257 ft (1602 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 6only 1 spring in 10 still has a frost later
  • Typical last frostApril 2450% chance of a frost after it
  • Typical first fall frostOctober 1850% chance of a frost before it
  • Frost-free season175 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Kim 10 SSE, COSpring: a frost after April 10 in 9 years out of 10, after April 24 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 18 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 175 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 24First frost ~Oct 18Frost season at Kim 10 SSE, COSpring: a frost after April 10 in 9 years out of 10, after April 24 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 18 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 175 days.JFMAMJJASONDLast frost ~Apr 24First frost ~Oct 18
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.Today

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)May 6October 4
50% (typical)April 24October 18
90% (likely)April 10October 29
Frost-free season (32°F, 50% chance)
175 days
Hard frost (28°F), last in spring, 50% chance after
April 11
Hard frost (28°F), first in fall, 50% chance before
October 28

The last 15 years (2006–2020 normals)

Typical last frost April 22 (2 days earlier than the 30-year normal), typical first fall frost October 21 (3 days later). Frost-free season 180 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 Kim 10 SSE: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 6, 20% May 2, 30% April 30, 40% April 27, 50% April 24, 60% April 21, 70% April 19, 80% April 15, 90% April 10. Observed last spring frost in recent years: 2021 April 30, 2022 April 17, 2023 April 29, 2024 April 17, 2025 May 15, 2026 May 9.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 6Apr 24Apr 102021: April 302022: April 172023: April 292024: April 172025: May 152026: May 9Fall at Kim 10 SSE: chance of a frost before this dateFall, chance of a frost before the date: 10% October 4, 20% October 8, 30% October 12, 40% October 15, 50% October 18, 60% October 20, 70% October 22, 80% October 26, 90% October 29. Observed first fall frost in recent years: 2021 October 16, 2022 October 13, 2023 October 14, 2024 October 31, 2025 October 19.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 4Oct 18Oct 292021: October 162022: October 132023: October 142024: October 312025: October 19
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
2021April 30October 16
2022April 17October 13
2023April 29October 14
2024April 17October 31
2025May 15October 19
2026May 9season not over yet

What these dates mean

The cautious fall date in Kim 10 SSE for finishing the harvest is October 4, when there is only a 10 % chance that a light frost has arrived. In spring the cautious date for setting out tender crops is May 6, which likewise carries a 10 % chance of a later light frost, while planting on April 10 would be a gamble with a 90 % chance of frost.

The 50% dates are April 24 in spring and October 18 in fall; at each of these dates there is an even chance of a frost occurring later (spring) or earlier (fall). The median hard-frost dates, when temperatures reach 28 °F, are April 11 and October 28, marking the points at which a deeper freeze becomes as likely as not.

A hard frost at 28 °F can injure plants that would survive a light frost at 32 °F, so it represents a greater risk to tender crops.

How to read the probabilities

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

  • Spring: "10% after May 6" 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 4" 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 Kim 10 SSE, CONumbered nearest stations: 1 — Kim 15 NNE, CO — 23 mi; 2 — Grenville, NM — 40 mi; 3 — Walsh, CO — 58 mi; 4 — near Trinidad, CO — 58 mi; 5 — Raton, NM — 64 mi.CONMOKTX25 mi · 40 km1. Kim 15 NNE, CO — 23 mi12. Grenville, NM — 40 mi23. Walsh, CO — 58 mi34. near Trinidad, CO — 58 mi45. Raton, NM — 64 mi5
  1. Kim 15 NNE, CO 23 mi (38 km)
  2. Grenville, NM 40 mi (65 km)
  3. Walsh, CO 58 mi (93 km)
  4. near Trinidad, CO 58 mi (93 km)
  5. Raton, NM 64 mi (103 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: 37.115, -103.2986.