U.S. Frost Dates by Weather Station

NOAA station USW00024015 · Colorado

Frost Dates for Akron Washington County Airport, CO

NOAA weather station Akron Washington County Airport (USW00024015), Colorado · elevation 4663 ft (1421 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 19only 1 spring in 10 still has a frost later
  • Typical last frostMay 650% chance of a frost after it
  • Typical first fall frostOctober 850% chance of a frost before it
  • Frost-free season155 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Akron Washington County Airport, COSpring: a frost after April 24 in 9 years out of 10, after May 6 in half of the years, after May 19 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 8 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 155 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 6First frost ~Oct 8Frost season at Akron Washington County Airport, COSpring: a frost after April 24 in 9 years out of 10, after May 6 in half of the years, after May 19 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 8 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 155 days.JFMAMJJASONDLast frost ~May 6First frost ~Oct 8
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 19September 27
50% (typical)May 6October 8
90% (likely)April 24October 20
Frost-free season (32°F, 50% chance)
155 days
Hard frost (28°F), last in spring, 50% chance after
April 27
Hard frost (28°F), first in fall, 50% chance before
October 17

The last 15 years (2006–2020 normals)

Typical last frost May 7 (1 day later than the 30-year normal), typical first fall frost October 12 (4 days later). Frost-free season 155 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 Akron Washington County Airport: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 19, 20% May 15, 30% May 11, 40% May 8, 50% May 6, 60% May 4, 70% May 2, 80% April 29, 90% April 24. Observed last spring frost in recent years: 2021 May 11, 2022 May 2, 2023 April 29, 2024 May 8, 2025 April 29, 2026 May 6.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 19May 6Apr 242021: May 112022: May 22023: April 292024: May 82025: April 292026: May 6Fall at Akron Washington County Airport: chance of a frost before this dateFall, chance of a frost before the date: 10% September 27, 20% October 1, 30% October 3, 40% October 6, 50% October 8, 60% October 11, 70% October 14, 80% October 16, 90% October 20. Observed first fall frost in recent years: 2021 October 13, 2022 October 17, 2023 October 13, 2024 October 30, 2025 October 18.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 27Oct 8Oct 202021: October 132022: October 172023: October 132024: October 302025: October 18
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 11October 13
2022May 2October 17
2023April 29October 13
2024May 8October 30
2025April 29October 18
2026May 6season not over yet

What these dates mean

May 19 is the cautious spring date at Akron Washington County Airport; with only a 10 % chance of a light frost later, it gives a gardener a low-risk point to set out tender crops. The 50 % spring date, May 6, marks the median point where a light frost is equally likely to occur later, while the 50 % fall date, October 8, is the median point where a light frost is equally likely to have arrived earlier. The hard-frost median dates are April 27 in spring and October 17 in fall, and they indicate when a 28 °F frost is as likely as not. September 27 is the cautious fall date, offering only a 10 % chance that a light frost has arrived earlier and therefore a reliable moment to finish harvesting tender crops. A hard frost matters more than a light frost because the colder temperature can damage plants that survive a 32 °F event.

How to read the probabilities

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

  • Spring: "10% after May 19" 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 27" 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 Akron Washington County Airport, CONumbered nearest stations: 1 — near Akron, CO — 4 mi; 2 — Yuma, CO — 26 mi; 3 — Leroy, CO — 27 mi; 4 — Joes, CO — 45 mi; 5 — Holyoke, CO — 53 mi.NEKS25 mi · 40 km1. near Akron, CO — 4 mi12. Yuma, CO — 26 mi23. Leroy, CO — 27 mi34. Joes, CO — 45 mi45. Holyoke, CO — 53 mi5
  1. near Akron, CO 4 mi (7 km)
  2. Yuma, CO 26 mi (42 km)
  3. Leroy, CO 27 mi (43 km)
  4. Joes, CO 45 mi (73 km)
  5. Holyoke, CO 53 mi (85 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: 40.1667, -103.2167.