U.S. Frost Dates by Weather Station

NOAA station USW00093815 · Ohio

Frost Dates for Dayton, OH

NOAA weather station Dayton International Airport (USW00093815), Ohio · elevation 1000 ft (305 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 1650% chance of a frost after it
  • Typical first fall frostOctober 2850% chance of a frost before it
  • Frost-free season194 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Dayton, OHSpring: a frost after April 2 in 9 years out of 10, after April 16 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 16 in 1 year out of 10, before October 28 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 194 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 16First frost ~Oct 28Frost season at Dayton, OHSpring: a frost after April 2 in 9 years out of 10, after April 16 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 16 in 1 year out of 10, before October 28 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 194 days.JFMAMJJASONDLast frost ~Apr 16First frost ~Oct 28
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 3October 16
50% (typical)April 16October 28
90% (likely)April 2November 9
Frost-free season (32°F, 50% chance)
194 days
Hard frost (28°F), last in spring, 50% chance after
April 4
Hard frost (28°F), first in fall, 50% chance before
November 6

The last 15 years (2006–2020 normals)

Typical last frost April 16 (same as the 30-year normal), typical first fall frost October 28. Frost-free season 195 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 Dayton: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 27, 30% April 23, 40% April 19, 50% April 16, 60% April 14, 70% April 10, 80% April 7, 90% April 2. Observed last spring frost in recent years: 2021 May 1, 2022 April 20, 2023 April 18, 2024 April 6, 2025 April 12, 2026 April 19.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 3Apr 16Apr 22021: May 12022: April 202023: April 182024: April 62025: April 122026: April 19Fall at Dayton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 16, 20% October 20, 30% October 24, 40% October 26, 50% October 28, 60% October 31, 70% November 1, 80% November 4, 90% November 9. Observed first fall frost in recent years: 2021 October 27, 2022 October 19, 2023 October 31, 2024 November 21, 2025 October 24.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 16Oct 28Nov 92021: October 272022: October 192023: October 312024: November 212025: October 24
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 27
2022April 20October 19
2023April 18October 31
2024April 6November 21
2025April 12October 24
2026April 19season not over yet

What these dates mean

October 16 marks the cautious fall date for finishing the harvest in Dayton, indicating only a 10% chance that a light frost has arrived earlier.

The 50% light-frost dates are April 16 in spring and October 28 in fall; each signals an even-odds point, so the risk of a frost is roughly balanced on either side of those days.

For tender crops, the cautious spring date is May 3, when a frost later is only a 10% chance, and the cautious fall date is October 16, when a frost earlier is also a 10% chance. Hard-frost (28 °F) 50% dates are April 4 and November 6, and they matter more than light frosts because the colder temperature can kill plant tissue that would survive a 32 °F 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 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 16" 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 Dayton, OHNumbered nearest stations: 1 — Dayton MCD, OH — 10 mi; 2 — Springfield, OH — 22 mi; 3 — Franklin, OH — 25 mi; 4 — Eaton, OH — 25 mi; 5 — Sidney, OH — 25 mi.IN25 mi · 40 km1. Dayton MCD, OH — 10 mi12. Springfield, OH — 22 mi23. Franklin, OH — 25 mi34. Eaton, OH — 25 mi45. Sidney, OH — 25 mi5
  1. Dayton MCD, OH 10 mi (16 km)
  2. Springfield, OH 22 mi (36 km)
  3. Franklin, OH 25 mi (40 km)
  4. Eaton, OH 25 mi (40 km)
  5. Sidney, OH 25 mi (41 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: 39.9061, -84.2186.