U.S. Frost Dates by Weather Station

NOAA station USC00202984 · Michigan

Frost Dates for Frankfort, MI

NOAA weather station Frankfort 2 NE (USC00202984), Michigan · elevation 948 ft (289 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 20only 1 spring in 10 still has a frost later
  • Typical last frostMay 250% chance of a frost after it
  • Typical first fall frostOctober 2650% chance of a frost before it
  • Frost-free season175 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Frankfort, MISpring: a frost after April 19 in 9 years out of 10, after May 2 in half of the years, after May 20 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 175 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 2First frost ~Oct 26Frost season at Frankfort, MISpring: a frost after April 19 in 9 years out of 10, after May 2 in half of the years, after May 20 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 175 days.JFMAMJJASONDLast frost ~May 2First frost ~Oct 26
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 20October 7
50% (typical)May 2October 26
90% (likely)April 19November 9
Frost-free season (32°F, 50% chance)
175 days
Hard frost (28°F), last in spring, 50% chance after
April 20
Hard frost (28°F), first in fall, 50% chance before
November 7

The last 15 years (2006–2020 normals)

Typical last frost April 30 (2 days earlier than the 30-year normal), typical first fall frost October 31 (5 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 Frankfort: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 20, 20% May 14, 30% May 9, 40% May 6, 50% May 2, 60% April 30, 70% April 27, 80% April 23, 90% April 19. Observed last spring frost in recent years: 2021 May 1, 2022 April 28, 2023 May 2, 2024 April 25, 2025 April 30, 2026 May 11.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 20May 2Apr 192021: May 12022: April 282023: May 22024: April 252025: April 302026: May 11Fall at Frankfort: chance of a frost before this dateFall, chance of a frost before the date: 10% October 7, 20% October 14, 30% October 19, 40% October 22, 50% October 26, 60% October 30, 70% November 1, 80% November 4, 90% November 9. Observed first fall frost in recent years: 2021 November 4, 2022 November 12, 2023 October 31, 2024 November 12, 2025 November 8.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 7Oct 26Nov 92021: November 42022: November 122023: October 312024: November 122025: November 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
2021May 1November 4
2022April 28November 12
2023May 2October 31
2024April 25November 12
2025April 30November 8
2026May 11season not over yet

What these dates mean

October 7 is the cautious fall date for finishing the harvest in Frankfort, giving only a 10 % chance that a light frost has arrived earlier.

In spring the 50 % date is May 2, the point at which a light frost is equally likely to occur later in this location, while the 50 % fall date is October 26, when a light frost is equally likely to have occurred earlier. Gardeners who want to avoid frost risk plant tender crops after the cautious spring date of May 20 and pull them in before the cautious fall date of October 7.

A hard frost at 28 °F, marked by the 50 % dates of April 20 in spring and November 7 in fall, can damage plants that survive 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 20" 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 7" 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 Frankfort, MINumbered nearest stations: 1 — Manistee, MI — 30 mi; 2 — near Traverse City, MI — 31 mi; 3 — Cadillac, MI — 48 mi; 4 — Kalkaska, MI — 51 mi; 5 — Lake City, MI — 55 mi.MI25 mi · 40 km1. Manistee, MI — 30 mi12. near Traverse City, MI — 31 mi23. Cadillac, MI — 48 mi34. Kalkaska, MI — 51 mi45. Lake City, MI — 55 mi5
  1. Manistee, MI 30 mi (49 km)
  2. near Traverse City, MI 31 mi (51 km)
  3. Cadillac, MI 48 mi (77 km)
  4. Kalkaska, MI 51 mi (82 km)
  5. Lake City, MI 55 mi (88 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: 44.6483, -86.2097.