U.S. Frost Dates by Weather Station

NOAA station USC00332098 · Ohio

Frost Dates for Defiance, OH

NOAA weather station Defiance (USC00332098), Ohio · elevation 700 ft (213 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 8only 1 spring in 10 still has a frost later
  • Typical last frostApril 2250% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season183 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Defiance, OHSpring: a frost after April 10 in 9 years out of 10, after April 22 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 24 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 183 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 22First frost ~Oct 24Frost season at Defiance, OHSpring: a frost after April 10 in 9 years out of 10, after April 22 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 24 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 183 days.JFMAMJJASONDLast frost ~Apr 22First frost ~Oct 24
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 8October 11
50% (typical)April 22October 24
90% (likely)April 10November 6
Frost-free season (32°F, 50% chance)
183 days
Hard frost (28°F), last in spring, 50% chance after
April 10
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 22 (same as the 30-year normal), typical first fall frost October 25 (1 day later). Frost-free season 183 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 Defiance: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 8, 20% May 3, 30% April 30, 40% April 26, 50% April 22, 60% April 20, 70% April 17, 80% April 14, 90% April 10. Observed last spring frost in recent years: 2021 May 1, 2022 April 27, 2023 April 27, 2024 April 25, 2025 April 18.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 8Apr 22Apr 102021: May 12022: April 272023: April 272024: April 252025: April 18Fall at Defiance: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 16, 30% October 19, 40% October 21, 50% October 24, 60% October 27, 70% October 30, 80% November 1, 90% November 6. Observed first fall frost in recent years: 2021 October 24, 2022 October 8, 2023 October 31, 2024 October 17, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 24Nov 62021: October 242022: October 82023: 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 1October 24
2022April 27October 8
2023April 27October 31
2024April 25October 17
2025April 18October 25
2026incomplete recordseason not over yet

What these dates mean

May 8 is the cautious spring light-frost date for Defiance, carrying only a 10 % chance that a frost will occur later, so a gardener can plan to set out tender crops on that day with relatively low risk. The median light-frost date is April 22; at that point there is a 50 % chance of a frost later than this date. For hard frost, the 50 % date in spring is April 10, indicating equal odds of a 28 °F freeze occurring before or after that day.

In the fall the cautious light-frost date is October 11, when there is only a 10 % chance that a frost has already arrived, making it a suitable deadline for finishing tender harvests. The median fall light-frost date is October 24, with a 50 % chance of a frost earlier than this date. The hard-frost 50 % date in fall is November 4. A hard frost matters more because 28 °F can damage plant tissue that survives a 32 °F light frost.

How to read the probabilities

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

  • Spring: "10% after May 8" 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 Defiance, OHNumbered nearest stations: 1 — Wauseon, OH — 21 mi; 2 — Pandora, OH — 32 mi; 3 — near Toledo, OH — 37 mi; 4 — Garrett, IN — 38 mi; 5 — Lima, OH — 41 mi.INMI25 mi · 40 km1. Wauseon, OH — 21 mi12. Pandora, OH — 32 mi23. near Toledo, OH — 37 mi34. Garrett, IN — 38 mi45. Lima, OH — 41 mi5
  1. Wauseon, OH 21 mi (33 km)
  2. Pandora, OH 32 mi (51 km)
  3. near Toledo, OH 37 mi (60 km)
  4. Garrett, IN 38 mi (62 km)
  5. Lima, OH 41 mi (65 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: 41.2783, -84.3847.