U.S. Frost Dates by Weather Station

NOAA station USC00128290 · Indiana

Frost Dates for Spencer, IN

NOAA weather station Spencer (USC00128290), Indiana · elevation 549 ft (167 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 7only 1 spring in 10 still has a frost later
  • Typical last frostApril 2050% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season180 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Spencer, INSpring: a frost after April 6 in 9 years out of 10, after April 20 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 7 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: 180 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 20First frost ~Oct 20Frost season at Spencer, INSpring: a frost after April 6 in 9 years out of 10, after April 20 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 7 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: 180 days.JFMAMJJASONDLast frost ~Apr 20First 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 7October 7
50% (typical)April 20October 20
90% (likely)April 6November 1
Frost-free season (32°F, 50% chance)
180 days
Hard frost (28°F), last in spring, 50% chance after
April 7
Hard frost (28°F), first in fall, 50% chance before
October 31

The last 15 years (2006–2020 normals)

Typical last frost April 20 (same as the 30-year normal), typical first fall frost October 23 (3 days later). Frost-free season 184 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 Spencer: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 7, 20% May 1, 30% April 27, 40% April 23, 50% April 20, 60% April 17, 70% April 14, 80% April 11, 90% April 6. Observed last spring frost in recent years: 2021 April 23, 2022 April 20, 2023 April 25.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 7Apr 20Apr 62021: April 232022: April 202023: April 25Fall at Spencer: chance of a frost before this dateFall, chance of a frost before the date: 10% October 7, 20% October 11, 30% October 15, 40% October 17, 50% October 20, 60% October 23, 70% October 25, 80% October 28, 90% November 1. Observed first fall frost in recent years: 2021 November 3, 2022 October 9, 2023 October 31.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 7Oct 20Nov 12021: November 32022: October 92023: October 31
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 23November 3
2022April 20October 9
2023April 25October 31
2024incomplete recordincomplete record
2025incomplete recordno data
2026no dataseason not over yet

What these dates mean

Gardeners who set out tender crops on the early spring date of April 6 in Spencer face a 90 % chance that a frost will occur later, making it a gamble. A cautious plan uses the later date of May 7, which carries only a 10 % chance of a frost later than that day. In the fall, the cautious date for finishing tender crops is October 7, when there is only a 10 % chance that a frost has arrived earlier.

For gardeners, the 50 % dates give a midpoint of frost risk: the 50 % date is April 20, indicating an even chance of a frost later than this date, and the 50 % date is October 20, indicating an even chance of a frost earlier than this date. Hard-frost thresholds are colder; the 50 % hard-frost dates are April 7 and October 31, and a hard frost at 28 °F can damage plants that would survive a 32 °F light frost, so they matter more.

How to read the probabilities

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

  • Spring: "10% after May 7" 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 7" 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 Spencer, INNumbered nearest stations: 1 — near Bloomington, IN — 15 mi; 2 — Martinsville, IN — 19 mi; 3 — near Jasonville, IN — 27 mi; 4 — near Oolitic, IN — 30 mi; 5 — Indianapolis, IN — 39 mi.ILKY25 mi · 40 km1. near Bloomington, IN — 15 mi12. Martinsville, IN — 19 mi23. near Jasonville, IN — 27 mi34. near Oolitic, IN — 30 mi45. Indianapolis, IN — 39 mi5
  1. near Bloomington, IN 15 mi (25 km)
  2. Martinsville, IN 19 mi (30 km)
  3. near Jasonville, IN 27 mi (43 km)
  4. near Oolitic, IN 30 mi (48 km)
  5. Indianapolis, IN 39 mi (63 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: 39.2839, -86.7706.