U.S. Frost Dates by Weather Station

NOAA station USC00127482 · Indiana

Frost Dates for Rochester, IN

NOAA weather station Rochester (USC00127482), Indiana · elevation 760 ft (232 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 2150% chance of a frost before it
  • Frost-free season180 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Rochester, INSpring: a frost after April 9 in 9 years out of 10, after April 23 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 21 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 180 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 21Frost season at Rochester, INSpring: a frost after April 9 in 9 years out of 10, after April 23 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 21 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 180 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 21
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 9October 6
50% (typical)April 23October 21
90% (likely)April 9November 2
Frost-free season (32°F, 50% chance)
180 days
Hard frost (28°F), last in spring, 50% chance after
April 10
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 23 (same as the 30-year normal), typical first fall frost October 23 (2 days later). Frost-free season 182 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 Rochester: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 3, 30% April 29, 40% April 26, 50% April 23, 60% April 20, 70% April 18, 80% April 14, 90% April 9. Observed last spring frost in recent years: 2021 May 8, 2022 April 28, 2023 April 28, 2024 April 26, 2025 April 17, 2026 May 3.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 23Apr 92021: May 82022: April 282023: April 282024: April 262025: April 172026: May 3Fall at Rochester: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 12, 30% October 15, 40% October 18, 50% October 21, 60% October 23, 70% October 26, 80% October 29, 90% November 2. Observed first fall frost in recent years: 2021 October 28, 2022 October 18, 2023 October 31, 2024 October 17, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 21Nov 22021: October 282022: October 182023: October 312024: October 172025: October 25
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 8October 28
2022April 28October 18
2023April 28October 31
2024April 26October 17
2025April 17October 25
2026May 3season not over yet

What these dates mean

May 9 is the cautious spring date; with only a 10 % chance of a light frost after that day, a gardener can plan to set out tender crops with minimal risk. The 50 % date, April 23, marks the point where the chance of a frost later is even, helping to gauge the uncertainty around the cautious date.

In fall, October 6 is the cautious date for finishing the harvest of tender crops, because there is only a 10 % chance of a light frost earlier than that day. The 50 % date, October 21, indicates an even odds point for a frost occurring earlier. The hard-frost 50 % dates are April 10 in spring and November 1 in fall; a hard frost at 28 °F can damage plants that survive a 32 °F light frost, making it a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 9" 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 6" 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 Rochester, INNumbered nearest stations: 1 — Winamac, IN — 20 mi; 2 — Plymouth, IN — 20 mi; 3 — near Logansport, IN — 24 mi; 4 — Lakeville, IN — 32 mi; 5 — Columbia City, IN — 38 mi.OHMIIL25 mi · 40 km1. Winamac, IN — 20 mi12. Plymouth, IN — 20 mi23. near Logansport, IN — 24 mi34. Lakeville, IN — 32 mi45. Columbia City, IN — 38 mi5
  1. Winamac, IN 20 mi (32 km)
  2. Plymouth, IN 20 mi (32 km)
  3. near Logansport, IN 24 mi (38 km)
  4. Lakeville, IN 32 mi (51 km)
  5. Columbia City, IN 38 mi (61 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: 41.0664, -86.2097.