U.S. Frost Dates by Weather Station

NOAA station USC00203391 · Michigan

Frost Dates for Grayling, MI

NOAA weather station Grayling (USC00203391), Michigan · elevation 1137 ft (347 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 7only 1 spring in 10 still has a frost later
  • Typical last frostMay 2350% chance of a frost after it
  • Typical first fall frostSeptember 2750% chance of a frost before it
  • Frost-free season124 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Grayling, MISpring: a frost after May 6 in 9 years out of 10, after May 23 in half of the years, after June 7 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 27 in half of the years, before October 10 in 9 years out of 10. Typical frost-free season: 124 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 23First frost ~Sep 27Frost season at Grayling, MISpring: a frost after May 6 in 9 years out of 10, after May 23 in half of the years, after June 7 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 27 in half of the years, before October 10 in 9 years out of 10. Typical frost-free season: 124 days.JFMAMJJASONDLast frost ~May 23First frost ~Sep 27
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)June 7September 11
50% (typical)May 23September 27
90% (likely)May 6October 10
Frost-free season (32°F, 50% chance)
124 days
Hard frost (28°F), last in spring, 50% chance after
May 10
Hard frost (28°F), first in fall, 50% chance before
October 9

The last 15 years (2006–2020 normals)

Typical last frost May 21 (2 days earlier than the 30-year normal), typical first fall frost October 1 (4 days later). Frost-free season 131 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 Grayling: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 7, 20% June 1, 30% May 30, 40% May 26, 50% May 23, 60% May 21, 70% May 17, 80% May 13, 90% May 6. Observed last spring frost in recent years: 2021 June 22, 2022 June 4, 2023 May 28, 2024 May 7, 2025 May 20, 2026 May 22.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 7May 23May 62021: June 222022: June 42023: May 282024: May 72025: May 202026: May 22Fall at Grayling: chance of a frost before this dateFall, chance of a frost before the date: 10% September 11, 20% September 16, 30% September 21, 40% September 24, 50% September 27, 60% September 30, 70% October 2, 80% October 6, 90% October 10. Observed first fall frost in recent years: 2021 October 18, 2022 September 23, 2023 October 12, 2024 October 2, 2025 September 8.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 11Sep 27Oct 102021: October 182022: September 232023: October 122024: October 22025: September 8
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
2021June 22October 18
2022June 4September 23
2023May 28October 12
2024May 7October 2
2025May 20September 8
2026May 22season not over yet

What these dates mean

June 7 is the cautious spring date for Grayling, offering only a 10 % chance that a light frost will occur later and thus allowing a gardener to set out tender crops with minimal risk.

The 50 % light-frost date in spring is May 23, meaning there is an even chance of a frost later than that day, while the 50 % hard-frost date is May 10, indicating an even chance of a hard frost later. In the fall, the 50 % light-frost date is September 27, with an even chance of a frost earlier than it, and the 50 % hard-frost date is October 9, with an even chance of a hard frost earlier. September 11 is the cautious fall date, carrying only a 10 % chance that a light frost has already arrived and giving a gardener time to finish harvesting tender crops.

A hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, making it a more serious threat.

How to read the probabilities

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

  • Spring: "10% after June 7" 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 September 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 Grayling, MINumbered nearest stations: 1 — near Houghton Lake, MI — 20 mi; 2 — Kalkaska, MI — 24 mi; 3 — Gaylord, MI — 26 mi; 4 — Lake City, MI — 35 mi; 5 — near Boyne City, MI — 37 mi.25 mi · 40 km1. near Houghton Lake, MI — 20 mi12. Kalkaska, MI — 24 mi23. Gaylord, MI — 26 mi34. Lake City, MI — 35 mi45. near Boyne City, MI — 37 mi5
  1. near Houghton Lake, MI 20 mi (33 km)
  2. Kalkaska, MI 24 mi (38 km)
  3. Gaylord, MI 26 mi (42 km)
  4. Lake City, MI 35 mi (56 km)
  5. near Boyne City, MI 37 mi (59 km)

Sources

* Hardiness zone 5a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 44.6547, -84.6997.