U.S. Frost Dates by Weather Station

NOAA station USC00127999 · Indiana

Frost Dates for Shelbyville, IN

NOAA weather station Shelbyville Sewage Plant (USC00127999), Indiana · elevation 752 ft (229 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 1750% chance of a frost after it
  • Typical first fall frostOctober 2250% chance of a frost before it
  • Frost-free season187 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Shelbyville, INSpring: a frost after April 3 in 9 years out of 10, after April 17 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 22 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 187 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 17First frost ~Oct 22Frost season at Shelbyville, INSpring: a frost after April 3 in 9 years out of 10, after April 17 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 22 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 187 days.JFMAMJJASONDLast frost ~Apr 17First frost ~Oct 22
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 3October 9
50% (typical)April 17October 22
90% (likely)April 3November 4
Frost-free season (32°F, 50% chance)
187 days
Hard frost (28°F), last in spring, 50% chance after
April 5
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 17 (same as the 30-year normal), typical first fall frost October 25 (3 days later). Frost-free season 190 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 Shelbyville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 28, 30% April 23, 40% April 20, 50% April 17, 60% April 14, 70% April 11, 80% April 7, 90% April 3. Observed last spring frost in recent years: 2021 April 22, 2022 April 19, 2023 April 25, 2024 April 8, 2025 April 13, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 3Apr 17Apr 32021: April 222022: April 192023: April 252024: April 82025: April 132026: April 21Fall at Shelbyville: chance of a frost before this dateFall, chance of a frost before the date: 10% October 9, 20% October 13, 30% October 17, 40% October 19, 50% October 22, 60% October 24, 70% October 27, 80% October 30, 90% November 4. Observed first fall frost in recent years: 2022 October 20, 2023 October 31, 2024 October 17, 2025 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 9Oct 22Nov 42022: October 202023: 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
2021April 22incomplete record
2022April 19October 20
2023April 25October 31
2024April 8October 17
2025April 13October 24
2026April 21season not over yet

What these dates mean

The 187 days between the 50% dates in Shelbyville mark the period during which a light frost is equally likely to have occurred or not. The 50% date in spring is April 17 and the 50% date in fall is October 22; each represents a median point in the 28-year record where the chance of a 32°F frost is 50%.

For a cautious planting plan, the spring cautious date is May 3, when there is only a 10% chance of a later frost, while the early spring date of April 3 carries a 90% chance and is a gamble. In the autumn, the cautious date to finish harvesting tender crops is October 9, with a 10% chance that a frost has already arrived, whereas November 4 is a gamble with a 90% chance of an earlier frost. A hard frost, recorded at 28°F, is more damaging than a light frost, so the hard-frost 50% dates of April 5 in spring and November 1 in fall are important reference points.

How to read the probabilities

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

  • Spring: "10% after May 3" 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 9" 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 Shelbyville, INNumbered nearest stations: 1 — Rushville, IN — 19 mi; 2 — Greensburg, IN — 20 mi; 3 — Columbus, IN — 26 mi; 4 — Indianapolis, IN — 29 mi; 5 — New Castle, IN — 33 mi.INOHKY25 mi · 40 km1. Rushville, IN — 19 mi12. Greensburg, IN — 20 mi23. Columbus, IN — 26 mi34. Indianapolis, IN — 29 mi45. New Castle, IN — 33 mi5
  1. Rushville, IN 19 mi (30 km)
  2. Greensburg, IN 20 mi (33 km)
  3. Columbus, IN 26 mi (42 km)
  4. Indianapolis, IN 29 mi (46 km)
  5. New Castle, IN 33 mi (53 km)

Sources

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

Station coordinates: 39.5283, -85.7914.