U.S. Frost Dates by Weather Station

NOAA station USW00014858 · Michigan

Frost Dates for Hancock, MI

NOAA weather station Hancock Houghton County Airport (USW00014858), Michigan · elevation 1063 ft (324 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 3only 1 spring in 10 still has a frost later
  • Typical last frostMay 1750% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season138 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Hancock, MISpring: a frost after May 1 in 9 years out of 10, after May 17 in half of the years, after June 3 in 1 year out of 10. Fall: the first frost comes before September 16 in 1 year out of 10, before October 1 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 138 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 17First frost ~Oct 1Frost season at Hancock, MISpring: a frost after May 1 in 9 years out of 10, after May 17 in half of the years, after June 3 in 1 year out of 10. Fall: the first frost comes before September 16 in 1 year out of 10, before October 1 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 138 days.JFMAMJJASONDLast frost ~May 17First frost ~Oct 1
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 3September 16
50% (typical)May 17October 1
90% (likely)May 1October 18
Frost-free season (32°F, 50% chance)
138 days
Hard frost (28°F), last in spring, 50% chance after
May 2
Hard frost (28°F), first in fall, 50% chance before
October 14

The last 15 years (2006–2020 normals)

Typical last frost May 19 (2 days later than the 30-year normal), typical first fall frost October 5 (4 days later). Frost-free season 137 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 Hancock: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 3, 20% May 30, 30% May 24, 40% May 21, 50% May 17, 60% May 13, 70% May 9, 80% May 5, 90% May 1. 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 3May 17May 12021: May 292022: May 232023: May 252024: May 102025: May 192026: May 21Fall at Hancock: chance of a frost before this dateFall, chance of a frost before the date: 10% September 16, 20% September 22, 30% September 26, 40% September 29, 50% October 1, 60% October 4, 70% October 8, 80% October 11, 90% October 18. Observed first fall frost in recent years: 2021 November 2, 2022 September 28, 2023 October 7, 2024 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 16Oct 1Oct 182021: November 22022: September 282023: October 72024: October 9
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 29November 2
2022May 23September 28
2023May 25October 7
2024May 10October 9
2025May 19incomplete record
2026May 21season not over yet

What these dates mean

Setting tender crops on the early spring date, May 1, carries a 90 % chance of a frost later that season, making it a gamble for Hancock growers.

The 50 % light-frost dates—May 17 in spring and October 1 in fall—mark the point at which a frost is equally likely to occur before or after, so they are useful reference points for planning. A cautious schedule uses the June 3 date, which has only a 10 % chance of a later frost, for planting tender crops, and the September 16 date, which has only a 10 % chance of an earlier frost, for finishing harvest.

The 50 % hard-frost dates are May 2 and October 14, and a hard frost at 28 °F can damage plants that survive a light frost at 32 °F, so it is a more severe risk.

How to read the probabilities

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

  • Spring: "10% after June 3" 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 16" 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 Hancock, MINumbered nearest stations: 1 — Marquette (USW00094850), MI — 62 mi; 2 — Bergland Dam, MI — 64 mi; 3 — Marquette (USW00014838), MI — 67 mi; 4 — Stambaugh, MI — 77 mi; 5 — Grand Portage, MN — 79 mi.MIWIMN50 mi · 80 km1. Marquette (USW00094850), MI — 62 mi12. Bergland Dam, MI — 64 mi23. Marquette (USW00014838), MI — 67 mi34. Stambaugh, MI — 77 mi45. Grand Portage, MN — 79 mi5
  1. Marquette (USW00094850), MI 62 mi (100 km)
  2. Bergland Dam, MI 64 mi (104 km)
  3. Marquette (USW00014838), MI 67 mi (108 km)
  4. Stambaugh, MI 77 mi (124 km)
  5. Grand Portage, MN 79 mi (128 km)

Sources

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

Station coordinates: 47.1658, -88.4808.