U.S. Frost Dates by Weather Station

NOAA station USC00129670 · Indiana

Frost Dates for Winamac, IN

NOAA weather station Winamac 2 SSE (USC00129670), Indiana · elevation 690 ft (210 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 2550% chance of a frost after it
  • Typical first fall frostOctober 1850% chance of a frost before it
  • Frost-free season173 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Winamac, INSpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 18 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 173 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 25First frost ~Oct 18Frost season at Winamac, INSpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 18 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 173 days.JFMAMJJASONDLast frost ~Apr 25First frost ~Oct 18
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.Today

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 11October 1
50% (typical)April 25October 18
90% (likely)April 11October 31
Frost-free season (32°F, 50% chance)
173 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
October 29

The last 15 years (2006–2020 normals)

Typical last frost April 24 (1 day earlier than the 30-year normal), typical first fall frost October 21 (3 days later). Frost-free season 180 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 Winamac: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 5, 30% May 1, 40% April 28, 50% April 25, 60% April 22, 70% April 19, 80% April 15, 90% April 11. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 April 27, 2024 April 26, 2025 April 17, 2026 May 2.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 11Apr 25Apr 112021: May 112022: April 282023: April 272024: April 262025: April 172026: May 2Fall at Winamac: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 8, 30% October 12, 40% October 15, 50% October 18, 60% October 21, 70% October 23, 80% October 26, 90% October 31. Observed first fall frost in recent years: 2021 November 1, 2022 October 8, 2023 October 31, 2024 October 17, 2025 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 18Oct 312021: November 12022: October 82023: October 312024: October 172025: 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
2021May 11November 1
2022April 28October 8
2023April 27October 31
2024April 26October 17
2025April 17October 24
2026May 2season not over yet

What these dates mean

Setting out tender crops on April 11 in Winamac is a gamble, carrying a 90 % chance that a light frost will still occur later in the season. By contrast, the cautious spring date is May 11, when only a 10 % chance of a later frost remains.

The 50 % dates—April 25 for spring and October 18 for fall—are the points where a light frost is equally likely to have happened or not, providing a statistical midpoint for planning. A cautious autumn plan would aim to finish tender-crop harvest by October 1, the date with only a 10 % chance that a frost has already arrived.

Hard frost, measured at 28 °F, matters more than a 32 °F light frost because the lower temperature can kill plant tissue that would survive the milder chill.

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 October 1" 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 Winamac, INNumbered nearest stations: 1 — Rochester, IN — 20 mi; 2 — near Logansport, IN — 22 mi; 3 — Plymouth, IN — 25 mi; 4 — Rensselaer, IN — 32 mi; 5 — Wanatah, IN — 34 mi.ILMI25 mi · 40 km1. Rochester, IN — 20 mi12. near Logansport, IN — 22 mi23. Plymouth, IN — 25 mi34. Rensselaer, IN — 32 mi45. Wanatah, IN — 34 mi5
  1. Rochester, IN 20 mi (32 km)
  2. near Logansport, IN 22 mi (35 km)
  3. Plymouth, IN 25 mi (41 km)
  4. Rensselaer, IN 32 mi (51 km)
  5. Wanatah, IN 34 mi (55 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: 41.0267, -86.5867.