U.S. Frost Dates by Weather Station

NOAA station USC00156580 · Kentucky

Frost Dates for Princeton, KY

NOAA weather station Princeton 1 SE (USC00156580), Kentucky · elevation 497 ft (152 m) · hardiness zone 7a*

  • Lower-risk planting dateafter April 30only 1 spring in 10 still has a frost later
  • Typical last frostApril 1150% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season196 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Princeton, KYSpring: a frost after March 25 in 9 years out of 10, after April 11 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 24 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 196 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 11First frost ~Oct 24Frost season at Princeton, KYSpring: a frost after March 25 in 9 years out of 10, after April 11 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 24 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 196 days.JFMAMJJASONDLast frost ~Apr 11First frost ~Oct 24
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 30October 12
50% (typical)April 11October 24
90% (likely)March 25November 5
Frost-free season (32°F, 50% chance)
196 days
Hard frost (28°F), last in spring, 50% chance after
March 30
Hard frost (28°F), first in fall, 50% chance before
November 2

The last 15 years (2006–2020 normals)

Typical last frost April 8 (3 days earlier than the 30-year normal), typical first fall frost October 25 (1 day later). Frost-free season 199 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 Princeton: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 30, 20% April 24, 30% April 18, 40% April 14, 50% April 11, 60% April 7, 70% April 4, 80% March 31, 90% March 25. Observed last spring frost in recent years: 2021 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 30Apr 11Mar 252021: April 21Fall at Princeton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 12, 20% October 16, 30% October 19, 40% October 21, 50% October 24, 60% October 26, 70% October 28, 80% October 31, 90% November 5.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 12Oct 24Nov 5
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 21incomplete record
2022incomplete recordno data
2023no datano data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

April 30, the cautious spring date for Princeton, carries only a 10 % chance that a light frost will occur later, so it is a reasonable point for a gardener to set out tender crops. The 50 % date, April 11, marks the point at which a light frost is equally likely to occur later, while the hard-frost median of March 30 indicates the day on which a 28 °F frost is as likely as not.

For the autumn season, October 12 is the cautious fall date, with just a 10 % chance that a light frost has already arrived, allowing a gardener to finish harvesting tender crops. The 50 % date, October 24, is the even-odds point for a frost occurring earlier, and the hard-frost median of November 2 shows when a 28 °F frost becomes as likely as not. A hard frost matters more because it reaches a lower temperature that can damage plant tissue more severely than a light frost.

How to read the probabilities

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

  • Spring: "10% after April 30" 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 12" 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 Princeton, KYNumbered nearest stations: 1 — Smithland Lock and Dam, IL — 31 mi; 2 — Rosiclare, IL — 39 mi; 3 — Murray, KY — 43 mi; 4 — near Metropolis, IL — 43 mi; 5 — Dover, TN — 44 mi.ILMO25 mi · 40 km1. Smithland Lock and Dam, IL — 31 mi12. Rosiclare, IL — 39 mi23. Murray, KY — 43 mi34. near Metropolis, IL — 43 mi45. Dover, TN — 44 mi5
  1. Smithland Lock and Dam, IL 31 mi (50 km)
  2. Rosiclare, IL 39 mi (62 km)
  3. Murray, KY 43 mi (69 km)
  4. near Metropolis, IL 43 mi (70 km)
  5. Dover, TN 44 mi (71 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 37.1244, -87.8672.