U.S. Frost Dates by Weather Station

NOAA station USC00120852 · Indiana

Frost Dates for Boonville, IN

NOAA weather station Boonville 1 S (USC00120852), Indiana · elevation 400 ft (122 m) · hardiness zone 7a*

  • Lower-risk planting dateafter April 28only 1 spring in 10 still has a frost later
  • Typical last frostApril 1250% chance of a frost after it
  • Typical first fall frostOctober 2550% chance of a frost before it
  • Frost-free season196 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Boonville, INSpring: a frost after March 28 in 9 years out of 10, after April 12 in half of the years, after April 28 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 25 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 196 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 12First frost ~Oct 25Frost season at Boonville, INSpring: a frost after March 28 in 9 years out of 10, after April 12 in half of the years, after April 28 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 25 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 196 days.JFMAMJJASONDLast frost ~Apr 12First frost ~Oct 25
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 28October 12
50% (typical)April 12October 25
90% (likely)March 28November 5
Frost-free season (32°F, 50% chance)
196 days
Hard frost (28°F), last in spring, 50% chance after
March 30
Hard frost (28°F), first in fall, 50% chance before
November 3

The last 15 years (2006–2020 normals)

Typical last frost April 11 (1 day earlier than the 30-year normal), typical first fall frost October 28 (3 days later). Frost-free season 199 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 Boonville: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 28, 20% April 22, 30% April 18, 40% April 15, 50% April 12, 60% April 9, 70% April 6, 80% April 1, 90% March 28. Observed last spring frost in recent years: 2021 April 22, 2022 April 10, 2023 April 24, 2024 April 6, 2025 April 12, 2026 March 28.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 28Apr 12Mar 282021: April 222022: April 102023: April 242024: April 62025: April 122026: March 28Fall at Boonville: chance of a frost before this dateFall, chance of a frost before the date: 10% October 12, 20% October 17, 30% October 21, 40% October 23, 50% October 25, 60% October 28, 70% October 30, 80% November 1, 90% November 5. Observed first fall frost in recent years: 2021 November 3, 2022 October 9, 2023 October 31, 2024 November 24, 2025 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Dec 1Oct 12Oct 25Nov 52021: November 32022: October 92023: October 312024: November 242025: November 3
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 22November 3
2022April 10October 9
2023April 24October 31
2024April 6November 24
2025April 12November 3
2026March 28season not over yet

What these dates mean

October 12 is the cautious fall date to finish harvesting tender crops in Boonville. For spring planting, the cautious date is April 28, the point with only a 10% chance of a light frost later. The 50% dates—April 12 for spring and October 25 for fall—represent an even odds of a frost occurring on that date, providing a neutral reference for timing. The hard-frost 50% dates are March 30 and November 3, marking the median chance for a 28 °F frost. The interval between the two 32°F 50% dates spans 196 days, and the percentages are drawn from a 29-year record (1991-2020).

A hard frost at 28 °F can injure or kill plants that would otherwise survive a light frost at 32 °F, making the hard-frost dates especially important for protecting tender crops.

How to read the probabilities

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

  • Spring: "10% after April 28" 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 12" 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 Boonville, INNumbered nearest stations: 1 — Evansville, IN — 13 mi; 2 — Tell City, IN — 28 mi; 3 — Henderson, KY — 28 mi; 4 — Princeton, IN — 28 mi; 5 — Mount Vernon, IN — 35 mi.INKYIL25 mi · 40 km1. Evansville, IN — 13 mi12. Tell City, IN — 28 mi23. Henderson, KY — 28 mi34. Princeton, IN — 28 mi45. Mount Vernon, IN — 35 mi5
  1. Evansville, IN 13 mi (22 km)
  2. Tell City, IN 28 mi (45 km)
  3. Henderson, KY 28 mi (45 km)
  4. Princeton, IN 28 mi (46 km)
  5. Mount Vernon, IN 35 mi (56 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: 38.0303, -87.2736.