U.S. Frost Dates by Weather Station

NOAA station USC00129430 · Indiana

Frost Dates for West Lafayette, IN

NOAA weather station West Lafayette 6 NW (USC00129430), Indiana · elevation 708 ft (216 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season169 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at West Lafayette, INSpring: a frost after April 12 in 9 years out of 10, after April 26 in half of the years, after May 11 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 27 in 9 years out of 10. Typical frost-free season: 169 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 12Frost season at West Lafayette, INSpring: a frost after April 12 in 9 years out of 10, after April 26 in half of the years, after May 11 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 27 in 9 years out of 10. Typical frost-free season: 169 days.JFMAMJJASONDLast frost ~Apr 26First 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 11September 27
50% (typical)April 26October 12
90% (likely)April 12October 27
Frost-free season (32°F, 50% chance)
169 days
Hard frost (28°F), last in spring, 50% chance after
April 15
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost April 26 (same as the 30-year normal), typical first fall frost October 17 (5 days later). Frost-free season 173 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 West Lafayette: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 6, 30% May 2, 40% April 30, 50% April 26, 60% April 23, 70% April 21, 80% April 17, 90% April 12. Observed last spring frost in recent years: 2021 April 22, 2022 April 27, 2023 April 26, 2024 April 25, 2025 April 16, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 11Apr 26Apr 122021: April 222022: April 272023: April 262024: April 252025: April 162026: April 20Fall at West Lafayette: chance of a frost before this dateFall, chance of a frost before the date: 10% September 27, 20% October 1, 30% October 6, 40% October 9, 50% October 12, 60% October 15, 70% October 19, 80% October 22, 90% October 27. Observed first fall frost in recent years: 2021 October 27, 2022 October 4, 2023 October 31, 2025 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 27Oct 12Oct 272021: October 272022: October 42023: October 312025: October 24
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 22October 27
2022April 27October 4
2023April 26October 31
2024April 25incomplete record
2025April 16October 24
2026April 20season not over yet

What these dates mean

The 169-day span between the 32 °F 50 % dates—April 26 and October 12—defines the period in which light frosts are as likely to have occurred as not. For a gardener this means that once April 26 has passed, the odds of a later light frost drop to 50 %, and after October 12 the odds of an earlier light frost rise to 50 %.

The cautious date for setting out tender crops in spring is May 11, when there is only a 10 % chance of a later light frost; planting on April 12 carries a 90 % chance and is a gamble. In the fall the cautious date to finish harvesting tender crops is September 27, with only a 10 % chance that a light frost has already arrived; waiting until October 27 involves a 90 % chance of an earlier frost. The hard-frost 50 % dates are April 15 and October 25, and a hard frost at 28 °F can damage plants that survive a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after May 11" 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 West Lafayette, INNumbered nearest stations: 1 — Lafayette (Purdue University Airport), IN — 5 mi; 2 — Lafayette, IN — 13 mi; 3 — near Frankfort, IN — 28 mi; 4 — Rensselaer, IN — 32 mi; 5 — Hoopeston, IL — 36 mi.INIL25 mi · 40 km1. Lafayette (Purdue University Airport), IN — 5 mi12. Lafayette, IN — 13 mi23. near Frankfort, IN — 28 mi34. Rensselaer, IN — 32 mi45. Hoopeston, IL — 36 mi5
  1. Lafayette (Purdue University Airport), IN 5 mi (8 km)
  2. Lafayette, IN 13 mi (21 km)
  3. near Frankfort, IN 28 mi (46 km)
  4. Rensselaer, IN 32 mi (52 km)
  5. Hoopeston, IL 36 mi (59 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.475, -86.9919.