U.S. Frost Dates by Weather Station

NOAA station USC00200779 · Michigan

Frost Dates for Big Rapids, MI

NOAA weather station Big Rapids WTP (USC00200779), Michigan · elevation 898 ft (274 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 28only 1 spring in 10 still has a frost later
  • Typical last frostMay 1350% chance of a frost after it
  • Typical first fall frostOctober 250% chance of a frost before it
  • Frost-free season142 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Big Rapids, MISpring: a frost after April 28 in 9 years out of 10, after May 13 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 2 in half of the years, before October 16 in 9 years out of 10. Typical frost-free season: 142 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 13First frost ~Oct 2Frost season at Big Rapids, MISpring: a frost after April 28 in 9 years out of 10, after May 13 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 2 in half of the years, before October 16 in 9 years out of 10. Typical frost-free season: 142 days.JFMAMJJASONDLast frost ~May 13First frost ~Oct 2
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.Today

Frost dates (32°F)

Probability of frost, based on 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 28September 18
50% (typical)May 13October 2
90% (likely)April 28October 16
Frost-free season (32°F, 50% chance)
142 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 13

The last 15 years (2006–2020 normals)

Typical last frost May 9 (4 days earlier than the 30-year normal), typical first fall frost October 9 (7 days later). Frost-free season 150 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 Big Rapids: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 28, 20% May 23, 30% May 20, 40% May 17, 50% May 13, 60% May 9, 70% May 5, 80% May 2, 90% April 28. Observed last spring frost in recent years: 2021 May 30, 2022 May 9, 2024 April 27, 2025 May 10, 2026 May 11.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 28May 13Apr 282021: May 302022: May 92024: April 272025: May 102026: May 11Fall at Big Rapids: chance of a frost before this dateFall, chance of a frost before the date: 10% September 18, 20% September 23, 30% September 28, 40% October 1, 50% October 2, 60% October 4, 70% October 7, 80% October 10, 90% October 16. Observed first fall frost in recent years: 2021 October 24, 2022 October 3, 2023 October 12, 2024 October 7, 2025 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 18Oct 2Oct 162021: October 242022: October 32023: October 122024: October 72025: 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 30October 24
2022May 9October 3
2023incomplete recordOctober 12
2024April 27October 7
2025May 10October 9
2026May 11season not over yet

What these dates mean

Planting tender crops on April 28 in Big Rapids carries a 90% chance that a light frost will still occur later, so that timing is a gamble. The cautious spring window begins on May 28, when only a 10% chance of a later frost remains, giving growers a more reliable point to set out delicate seedlings.

Between those bounds the 50% date of May 13 marks the point at which a light frost is equally likely to happen later, while the 50% date of October 2 marks the point at which a light frost is equally likely to have already arrived. A prudent fall plan therefore uses September 18, the date with only a 10% chance that a frost has come earlier, to finish harvesting tender crops.

The median hard frost dates are April 30 in spring and October 13 in fall; a hard frost at 28 °F can damage plants that survive a light 32 °F frost, so it represents a higher risk. The two 32 °F 50% dates are 142 days apart.

How to read the probabilities

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

  • Spring: "10% after May 28" 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 18" 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 Big Rapids, MINumbered nearest stations: 1 — Cadillac, MI — 39 mi; 2 — Lake City, MI — 44 mi; 3 — Montague, MI — 50 mi; 4 — Gladwin, MI — 53 mi; 5 — near Norton Shores, MI — 53 mi.MI25 mi · 40 km1. Cadillac, MI — 39 mi12. Lake City, MI — 44 mi23. Montague, MI — 50 mi34. Gladwin, MI — 53 mi45. near Norton Shores, MI — 53 mi5
  1. Cadillac, MI 39 mi (62 km)
  2. Lake City, MI 44 mi (70 km)
  3. Montague, MI 50 mi (80 km)
  4. Gladwin, MI 53 mi (85 km)
  5. near Norton Shores, MI 53 mi (85 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: 43.7072, -85.4819.