U.S. Frost Dates by Weather Station

NOAA station USC00336118 · Ohio

Frost Dates for Norwalk, OH

NOAA weather station Norwalk WWTP (USC00336118), Ohio · elevation 670 ft (204 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2550% chance of a frost after it
  • Typical first fall frostOctober 2550% chance of a frost before it
  • Frost-free season183 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Norwalk, OHSpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 25 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 183 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 25First frost ~Oct 25Frost season at Norwalk, OHSpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 25 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 183 days.JFMAMJJASONDLast frost ~Apr 25First frost ~Oct 25
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 9October 11
50% (typical)April 25October 25
90% (likely)April 11November 7
Frost-free season (32°F, 50% chance)
183 days
Hard frost (28°F), last in spring, 50% chance after
April 12
Hard frost (28°F), first in fall, 50% chance before
November 5

The last 15 years (2006–2020 normals)

Typical last frost April 24 (1 day earlier than the 30-year normal), typical first fall frost October 25. 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 Norwalk: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 4, 30% May 1, 40% April 28, 50% April 25, 60% April 22, 70% April 19, 80% April 16, 90% April 11. Observed last spring frost in recent years: 2021 May 1, 2022 April 29, 2023 April 27, 2024 April 26, 2025 April 17, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 25Apr 112021: May 12022: April 292023: April 272024: April 262025: April 172026: April 20Fall at Norwalk: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 15, 30% October 20, 40% October 22, 50% October 25, 60% October 28, 70% October 31, 80% November 3, 90% November 7. Observed first fall frost in recent years: 2021 November 3, 2022 October 29, 2023 October 23, 2024 October 27, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 25Nov 72021: November 32022: October 292023: October 232024: October 272025: 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 1November 3
2022April 29October 29
2023April 27October 23
2024April 26October 27
2025April 17October 25
2026April 20season not over yet

What these dates mean

October 11 marks the cautious fall date in Norwalk for finishing the harvest, when there is only a 10 % chance that a light frost has already arrived. In spring the cautious date for setting out tender crops is May 9, which carries a 10 % chance of a frost later than that day, while planting on April 11 would be a gamble with a 90 % chance of frost.

The 50% date is April 25, indicating a 50 % chance of a frost later than this date, and the 50% date is October 25, indicating a 50 % chance of a frost earlier than this date. For hard frosts the 50% dates are April 12 in spring and November 5 in fall.

Hard frost at 28 °F matters more than light frost at 32 °F because it can freeze plant tissue that would otherwise survive a 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 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 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 Norwalk, OHNumbered nearest stations: 1 — Sandusky, OH — 14 mi; 2 — near Mansfield, OH — 31 mi; 3 — Bucyrus, OH — 36 mi; 4 — Cleveland, OH — 41 mi; 5 — Wooster, OH — 49 mi.OH25 mi · 40 km1. Sandusky, OH — 14 mi12. near Mansfield, OH — 31 mi23. Bucyrus, OH — 36 mi34. Cleveland, OH — 41 mi45. Wooster, OH — 49 mi5
  1. Sandusky, OH 14 mi (22 km)
  2. near Mansfield, OH 31 mi (50 km)
  3. Bucyrus, OH 36 mi (59 km)
  4. Cleveland, OH 41 mi (65 km)
  5. Wooster, OH 49 mi (80 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: 41.2667, -82.6167.