U.S. Frost Dates by Weather Station

NOAA station USC00056306 · Colorado

Frost Dates for Paonia, CO

NOAA weather station Paonia 1 SW (USC00056306), Colorado · elevation 5581 ft (1701 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 18only 1 spring in 10 still has a frost later
  • Typical last frostMay 350% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season159 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Paonia, COSpring: a frost after April 22 in 9 years out of 10, after May 3 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 12 in half of the years, before October 25 in 9 years out of 10. Typical frost-free season: 159 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 3First frost ~Oct 12Frost season at Paonia, COSpring: a frost after April 22 in 9 years out of 10, after May 3 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 27 in 1 year out of 10, before October 12 in half of the years, before October 25 in 9 years out of 10. Typical frost-free season: 159 days.JFMAMJJASONDLast frost ~May 3First frost ~Oct 12
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 18September 27
50% (typical)May 3October 12
90% (likely)April 22October 25
Frost-free season (32°F, 50% chance)
159 days
Hard frost (28°F), last in spring, 50% chance after
April 23
Hard frost (28°F), first in fall, 50% chance before
October 21

The last 15 years (2006–2020 normals)

Typical last frost May 4 (1 day later than the 30-year normal), typical first fall frost October 13 (1 day later). Frost-free season 160 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 Paonia: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 18, 20% May 14, 30% May 9, 40% May 5, 50% May 3, 60% May 1, 70% April 29, 80% April 26, 90% April 22.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 18May 3Apr 22Fall at Paonia: chance of a frost before this dateFall, chance of a frost before the date: 10% September 27, 20% October 1, 30% October 5, 40% October 8, 50% October 12, 60% October 15, 70% October 18, 80% October 21, 90% October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 27Oct 12Oct 25
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.

What these dates mean

The 159 days between the 50% dates in Paonia frame the interval where light frosts are equally likely to have occurred or not. The 50% date is May 3, meaning there is a 50% chance of a light frost later than this date, and the 50% date is October 12, meaning there is a 50% chance of a light frost earlier than this date. The median hard-frost dates are April 23 and October 21, marking the points at which a 28 °F frost is as likely as not.

For a cautious planting plan, the spring date to set out tender crops is May 18, which carries only a 10% chance of a later light frost. In the fall, the cautious date to finish harvesting tender crops is September 27, with only a 10% chance that a light frost has arrived earlier. A hard frost at 28 °F matters more than a light frost at 32 °F because it can injure plants that survive the milder temperature.

How to read the probabilities

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

  • Spring: "10% after May 18" 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 Paonia, CONumbered nearest stations: 1 — Palisade, CO — 43 mi; 2 — Grand Junction, CO — 47 mi; 3 — Grand Junction (Walker Field), CO — 53 mi; 4 — Cochetopa Creek, CO — 54 mi; 5 — Taylor Park, CO — 55 mi.25 mi · 40 km1. Palisade, CO — 43 mi12. Grand Junction, CO — 47 mi23. Grand Junction (Walker Field), CO — 53 mi34. Cochetopa Creek, CO — 54 mi45. Taylor Park, CO — 55 mi5
  1. Palisade, CO 43 mi (69 km)
  2. Grand Junction, CO 47 mi (76 km)
  3. Grand Junction (Walker Field), CO 53 mi (85 km)
  4. Cochetopa Creek, CO 54 mi (88 km)
  5. Taylor Park, CO 55 mi (88 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: 38.8522, -107.6225.