U.S. Frost Dates by Weather Station

NOAA station USW00094850 · Michigan

Frost Dates for Marquette (USW00094850), MI

NOAA weather station Marquette (USW00094850), Michigan · elevation 1411 ft (430 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 4only 1 spring in 10 still has a frost later
  • Typical last frostMay 2250% chance of a frost after it
  • Typical first fall frostSeptember 2950% chance of a frost before it
  • Frost-free season129 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Marquette (USW00094850), MISpring: a frost after May 6 in 9 years out of 10, after May 22 in half of the years, after June 4 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 29 in half of the years, before October 12 in 9 years out of 10. Typical frost-free season: 129 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 22First frost ~Sep 29Frost season at Marquette (USW00094850), MISpring: a frost after May 6 in 9 years out of 10, after May 22 in half of the years, after June 4 in 1 year out of 10. Fall: the first frost comes before September 11 in 1 year out of 10, before September 29 in half of the years, before October 12 in 9 years out of 10. Typical frost-free season: 129 days.JFMAMJJASONDLast frost ~May 22First frost ~Sep 29
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 4September 11
50% (typical)May 22September 29
90% (likely)May 6October 12
Frost-free season (32°F, 50% chance)
129 days
Hard frost (28°F), last in spring, 50% chance after
May 8
Hard frost (28°F), first in fall, 50% chance before
October 10

The last 15 years (2006–2020 normals)

Typical last frost May 21 (1 day earlier than the 30-year normal), typical first fall frost October 1 (2 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 Marquette (USW00094850): chance of a frost after this dateSpring, chance of a frost after the date: 10% June 4, 20% June 1, 30% May 29, 40% May 26, 50% May 22, 60% May 19, 70% May 15, 80% May 11, 90% May 6. Observed last spring frost in recent years: 2021 May 29, 2022 May 23, 2023 May 25, 2024 May 10, 2025 May 19, 2026 May 21.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 4May 22May 62021: May 292022: May 232023: May 252024: May 102025: May 192026: May 21Fall at Marquette (USW00094850): chance of a frost before this dateFall, chance of a frost before the date: 10% September 11, 20% September 18, 30% September 22, 40% September 25, 50% September 29, 60% October 1, 70% October 4, 80% October 7, 90% October 12. Observed first fall frost in recent years: 2021 October 18, 2022 September 23, 2023 October 11, 2024 October 9, 2025 October 8.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 11Sep 29Oct 122021: October 182022: September 232023: October 112024: October 92025: October 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 29October 18
2022May 23September 23
2023May 25October 11
2024May 10October 9
2025May 19October 8
2026May 21season not over yet

What these dates mean

The 129 days between the 32°F 50% dates—May 22 and September 29—frame the period in which tender crops can be grown with the lowest overall frost risk.

The 50% dates are median points with an even chance of a light frost; they are not frost dates themselves. In spring, the cautious date for setting out tender crops is June 4, which carries only a 10% chance of a frost later, while the early-season gamble of May 6 has a 90% chance. In fall, the cautious date to finish harvesting tender crops is September 11, with a 10% chance of a frost earlier, and the later gamble of October 12 involves a 90% chance.

A hard frost at 28°F can damage plant tissue more severely than a light frost at 32°F.

How to read the probabilities

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

  • Spring: "10% after June 4" 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 Marquette (USW00094850), MINumbered nearest stations: 1 — Marquette (USW00014838), MI — 8 mi; 2 — Chatham Experiment Farm 2, MI — 32 mi; 3 — Munising, MI — 43 mi; 4 — near Kingsford, MI — 58 mi; 5 — Stambaugh, MI — 61 mi.MIWI25 mi · 40 km1. Marquette (USW00014838), MI — 8 mi12. Chatham Experiment Farm 2, MI — 32 mi23. Munising, MI — 43 mi34. near Kingsford, MI — 58 mi45. Stambaugh, MI — 61 mi5
  1. Marquette (USW00014838), MI 8 mi (13 km)
  2. Chatham Experiment Farm 2, MI 32 mi (52 km)
  3. Munising, MI 43 mi (69 km)
  4. near Kingsford, MI 58 mi (93 km)
  5. Stambaugh, MI 61 mi (98 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: 46.5311, -87.5483.