U.S. Frost Dates by Weather Station

NOAA station USC00120784 · Indiana

Frost Dates near Bloomington, IN

NOAA weather station Bloomington Indiana University (USC00120784), Indiana · elevation 830 ft (253 m) · hardiness zone 6b*

Bloomington is the nearest town to the station (0.7 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 1550% chance of a frost after it
  • Typical first fall frostOctober 2650% chance of a frost before it
  • Frost-free season192 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season near Bloomington, INSpring: a frost after March 31 in 9 years out of 10, after April 15 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 192 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 15First frost ~Oct 26Frost season near Bloomington, INSpring: a frost after March 31 in 9 years out of 10, after April 15 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 192 days.JFMAMJJASONDLast frost ~Apr 15First frost ~Oct 26
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 3October 11
50% (typical)April 15October 26
90% (likely)March 31November 9
Frost-free season (32°F, 50% chance)
192 days
Hard frost (28°F), last in spring, 50% chance after
April 2
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 14 (1 day earlier than the 30-year normal), typical first fall frost October 28 (2 days later). Frost-free season 196 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 near Bloomington: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 28, 30% April 22, 40% April 18, 50% April 15, 60% April 10, 70% April 7, 80% April 4, 90% March 31. Observed last spring frost in recent years: 2021 May 7, 2022 April 20, 2023 April 26, 2024 April 7, 2025 April 12, 2026 March 29.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 3Apr 15Mar 312021: May 72022: April 202023: April 262024: April 72025: April 122026: March 29Fall near Bloomington: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 18, 30% October 21, 40% October 24, 50% October 26, 60% October 29, 70% October 31, 80% November 2, 90% November 9. Observed first fall frost in recent years: 2021 November 3, 2022 October 18, 2023 October 31, 2024 October 17, 2025 November 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 26Nov 92021: November 32022: October 182023: October 312024: October 172025: November 10
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 7November 3
2022April 20October 18
2023April 26October 31
2024April 7October 17
2025April 12November 10
2026March 29season not over yet

What these dates mean

The cautious spring date for the Bloomington area is the late date May 3, when there is only a 10% chance of a frost after it, so gardeners plan to start tender crops after that point. By then the risk has dropped enough to make a planting schedule viable, while the middle date April 15 marks the typical date with a 50% chance of a frost after it, and the early date March 31, with a 90% chance of a frost after it, remains a gamble.

In the fall the cautious date is the early date October 11, which carries only a 10% chance of a frost before it, giving growers a window to finish harvesting tender crops. The middle date October 26 marks the typical date with a 50% chance of a frost before it, and the late date November 9, with a 90% chance of a frost before it, is a gamble for extending the season.

The frost-free season, defined by a 50% chance of a 32 °F frost, lasts about 192 days. A hard frost (28 °F) is more damaging to tender crops than a light frost (32 °F) because it can injure plant tissue more severely.

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 11" 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 Bloomington, INNumbered nearest stations: 1 — Spencer, IN — 15 mi; 2 — Martinsville, IN — 16 mi; 3 — near Oolitic, IN — 20 mi; 4 — Columbus, IN — 32 mi; 5 — near Jasonville, IN — 39 mi.IL25 mi · 40 km1. Spencer, IN — 15 mi12. Martinsville, IN — 16 mi23. near Oolitic, IN — 20 mi34. Columbus, IN — 32 mi45. near Jasonville, IN — 39 mi5
  1. Spencer, IN 15 mi (25 km)
  2. Martinsville, IN 16 mi (26 km)
  3. near Oolitic, IN 20 mi (32 km)
  4. Columbus, IN 32 mi (52 km)
  5. near Jasonville, IN 39 mi (62 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: 39.1742, -86.5214.