U.S. Frost Dates by Weather Station

NOAA station USC00125337 · Indiana

Frost Dates for Marion, IN

NOAA weather station Marion 2 N (USC00125337), Indiana · elevation 790 ft (241 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 12only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season175 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Marion, INSpring: a frost after April 11 in 9 years out of 10, after April 26 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 175 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 20Frost season at Marion, INSpring: a frost after April 11 in 9 years out of 10, after April 26 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 175 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 20
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 12October 5
50% (typical)April 26October 20
90% (likely)April 11November 1
Frost-free season (32°F, 50% chance)
175 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 24 (2 days earlier than the 30-year normal), typical first fall frost October 22 (2 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 Marion: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 12, 20% May 7, 30% May 3, 40% April 30, 50% April 26, 60% April 22, 70% April 19, 80% April 16, 90% April 11. Observed last spring frost in recent years: 2021 May 11, 2023 April 27, 2024 April 8, 2025 April 13, 2026 May 3.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 12Apr 26Apr 112021: May 112023: April 272024: April 82025: April 132026: May 3Fall at Marion: chance of a frost before this dateFall, chance of a frost before the date: 10% October 5, 20% October 11, 30% October 15, 40% October 17, 50% October 20, 60% October 22, 70% October 25, 80% October 28, 90% November 1. Observed first fall frost in recent years: 2021 October 27, 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 5Oct 20Nov 12021: October 272022: 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 11October 27
2022incomplete recordOctober 8
2023April 27October 31
2024April 8October 17
2025April 13October 24
2026May 3season not over yet

What these dates mean

Setting out tender crops on the early spring date, April 11, is a gamble in Marion; there is a 90% chance that a light frost will occur later than that day.

The 50% spring date, April 26, marks the point where a light frost has a 50% chance of occurring later, while the 50% fall date, October 20, indicates an even odds that a light frost will have arrived earlier. For hard frost, the median dates are April 14 in spring and November 1 in fall, each representing a 50% chance of temperatures dropping to 28 °F.

A cautious planting plan uses the May 12 date, which carries only a 10% chance of a later light frost, and the October 5 date, which carries a 10% chance that a light frost has already arrived. Hard frosts matter more because 28 °F can injure plants that survive a 32 °F 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 May 12" 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 5" 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 Marion, INNumbered nearest stations: 1 — Huntington, IN — 21 mi; 2 — Hartford City, IN — 22 mi; 3 — Kokomo, IN — 28 mi; 4 — Bluffton, IN — 31 mi; 5 — Anderson, IN — 32 mi.OH25 mi · 40 km1. Huntington, IN — 21 mi12. Hartford City, IN — 22 mi23. Kokomo, IN — 28 mi34. Bluffton, IN — 31 mi45. Anderson, IN — 32 mi5
  1. Huntington, IN 21 mi (33 km)
  2. Hartford City, IN 22 mi (35 km)
  3. Kokomo, IN 28 mi (46 km)
  4. Bluffton, IN 31 mi (50 km)
  5. Anderson, IN 32 mi (52 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: 40.58, -85.6586.