U.S. Frost Dates by Weather Station

NOAA station USW00093821 · Kentucky

Frost Dates for Louisville, KY

NOAA weather station Louisville International Airport (USW00093821), Kentucky · elevation 488 ft (149 m) · hardiness zone 7a*

  • Lower-risk planting dateafter April 16only 1 spring in 10 still has a frost later
  • Typical last frostMarch 3150% chance of a frost after it
  • Typical first fall frostNovember 750% chance of a frost before it
  • Frost-free season222 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Louisville, KYSpring: a frost after March 14 in 9 years out of 10, after March 31 in half of the years, after April 16 in 1 year out of 10. Fall: the first frost comes before October 28 in 1 year out of 10, before November 7 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 222 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 31First frost ~Nov 7Frost season at Louisville, KYSpring: a frost after March 14 in 9 years out of 10, after March 31 in half of the years, after April 16 in 1 year out of 10. Fall: the first frost comes before October 28 in 1 year out of 10, before November 7 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 222 days.JFMAMJJASONDLast frost ~Mar 31First frost ~Nov 7
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 16October 28
50% (typical)March 31November 7
90% (likely)March 14November 23
Frost-free season (32°F, 50% chance)
222 days
Hard frost (28°F), last in spring, 50% chance after
March 20
Hard frost (28°F), first in fall, 50% chance before
November 17

The last 15 years (2006–2020 normals)

Typical last frost March 31 (same as the 30-year normal), typical first fall frost November 6 (1 day earlier). Frost-free season 222 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 Louisville: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 16, 20% April 9, 30% April 4, 40% April 1, 50% March 31, 60% March 28, 70% March 24, 80% March 20, 90% March 14. Observed last spring frost in recent years: 2021 April 2, 2022 April 10, 2023 March 20, 2024 March 24, 2025 April 8, 2026 March 18.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1Apr 16Mar 31Mar 142021: April 22022: April 102023: March 202024: March 242025: April 82026: March 18Fall at Louisville: chance of a frost before this dateFall, chance of a frost before the date: 10% October 28, 20% November 1, 30% November 2, 40% November 4, 50% November 7, 60% November 10, 70% November 12, 80% November 17, 90% November 23. Observed first fall frost in recent years: 2021 November 4, 2022 October 20, 2023 October 31, 2024 November 29, 2025 November 9.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 28Nov 7Nov 232021: November 42022: October 202023: October 312024: November 292025: November 9
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 2November 4
2022April 10October 20
2023March 20October 31
2024March 24November 29
2025April 8November 9
2026March 18season not over yet

What these dates mean

April 16 is the cautious light-frost date for spring in Louisville; with only a 10 % chance of a frost later, a gardener can plan to set out tender crops after that day.

The median light-frost date in spring is March 31, meaning a 50 % chance of a frost occurring later; the median light-frost date in fall is November 7, meaning a 50 % chance of a frost occurring earlier. The median hard-frost dates are March 20 and November 17.

October 28 is the cautious fall light-frost date, with only a 10 % chance that a frost has arrived earlier, so harvest of tender crops can be finished by then. A hard frost at 28 °F can injure plants that survive a light frost at 32 °F, making the hard-frost dates especially important.

How to read the probabilities

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

  • Spring: "10% after April 16" 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 28" 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 Louisville, KYNumbered nearest stations: 1 — near Shepherdsville, KY — 19 mi; 2 — Bardstown, KY — 32 mi; 3 — Paoli, IN — 48 mi; 4 — near French Lick, IN — 55 mi; 5 — Rough River Lake, KY — 57 mi.25 mi · 40 km1. near Shepherdsville, KY — 19 mi12. Bardstown, KY — 32 mi23. Paoli, IN — 48 mi34. near French Lick, IN — 55 mi45. Rough River Lake, KY — 57 mi5
  1. near Shepherdsville, KY 19 mi (30 km)
  2. Bardstown, KY 32 mi (51 km)
  3. Paoli, IN 48 mi (77 km)
  4. near French Lick, IN 55 mi (89 km)
  5. Rough River Lake, KY 57 mi (92 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: 38.1811, -85.7392.