U.S. Frost Dates by Weather Station

NOAA station USC00337693 · Ohio

Frost Dates for Sidney, OH

NOAA weather station Sidney 1 S (USC00337693), Ohio · elevation 940 ft (287 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 12only 1 spring in 10 still has a frost later
  • Typical last frostApril 2750% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season175 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Sidney, OHSpring: a frost after April 12 in 9 years out of 10, after April 27 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 175 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 27First frost ~Oct 20Frost season at Sidney, OHSpring: a frost after April 12 in 9 years out of 10, after April 27 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before October 5 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 175 days.JFMAMJJASONDLast frost ~Apr 27First 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 12October 5
50% (typical)April 27October 20
90% (likely)April 12November 2
Frost-free season (32°F, 50% chance)
175 days
Hard frost (28°F), last in spring, 50% chance after
April 16
Hard frost (28°F), first in fall, 50% chance before
October 31

The last 15 years (2006–2020 normals)

Typical last frost April 25 (2 days earlier than the 30-year normal), typical first fall frost October 22 (2 days later). Frost-free season 180 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 Sidney: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 12, 20% May 6, 30% May 3, 40% April 30, 50% April 27, 60% April 23, 70% April 20, 80% April 17, 90% April 12. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 April 27, 2025 April 17, 2026 May 3.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 12Apr 27Apr 122021: May 112022: April 282023: April 272025: April 172026: May 3Fall at Sidney: chance of a frost before this dateFall, chance of a frost before the date: 10% October 5, 20% October 10, 30% October 14, 40% October 18, 50% October 20, 60% October 23, 70% October 26, 80% October 29, 90% November 2. Observed first fall frost in recent years: 2023 October 23, 2024 October 17.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 5Oct 20Nov 22023: October 232024: October 17
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 11incomplete record
2022April 28incomplete record
2023April 27October 23
2024incomplete recordOctober 17
2025April 17incomplete record
2026May 3season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Sidney is October 5, when there is only a 10 % chance that a light frost has arrived.

For a gardener, the 50 % dates mark the point where frost is equally likely to have occurred or not. The median light-frost date in spring is April 27 and the median in fall is October 20. The median hard-frost dates are April 16 and October 31. The cautious spring date for setting out tender crops is May 12, which carries a 10 % chance of a later frost, while the early-spring date of April 12 carries a 90 % chance and is a gamble.

A hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so those dates are especially important for protecting tender crops.

How to read the probabilities

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

  • Spring: "10% after May 12" 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 5" 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 Sidney, OHNumbered nearest stations: 1 — Bellefontaine, OH — 21 mi; 2 — Urbana, OH — 23 mi; 3 — Dayton, OH — 25 mi; 4 — Springfield, OH — 27 mi; 5 — Greenville, OH — 29 mi.OHIN25 mi · 40 km1. Bellefontaine, OH — 21 mi12. Urbana, OH — 23 mi23. Dayton, OH — 25 mi34. Springfield, OH — 27 mi45. Greenville, OH — 29 mi5
  1. Bellefontaine, OH 21 mi (33 km)
  2. Urbana, OH 23 mi (37 km)
  3. Dayton, OH 25 mi (41 km)
  4. Springfield, OH 27 mi (44 km)
  5. Greenville, OH 29 mi (46 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: 40.2706, -84.1508.