U.S. Frost Dates by Weather Station

NOAA station USC00206184 · Michigan

Frost Dates for Onaway, MI

NOAA weather station Onaway 4 N (USC00206184), Michigan · elevation 745 ft (227 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 2only 1 spring in 10 still has a frost later
  • Typical last frostMay 2250% chance of a frost after it
  • Typical first fall frostOctober 250% chance of a frost before it
  • Frost-free season135 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Onaway, MISpring: a frost after May 3 in 9 years out of 10, after May 22 in half of the years, after June 2 in 1 year out of 10. Fall: the first frost comes before September 16 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: 135 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 22First frost ~Oct 2Frost season at Onaway, MISpring: a frost after May 3 in 9 years out of 10, after May 22 in half of the years, after June 2 in 1 year out of 10. Fall: the first frost comes before September 16 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: 135 days.JFMAMJJASONDLast frost ~May 22First 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.

Frost dates (32°F)

Probability of frost, based on 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 2September 16
50% (typical)May 22October 2
90% (likely)May 3October 16
Frost-free season (32°F, 50% chance)
135 days
Hard frost (28°F), last in spring, 50% chance after
May 7
Hard frost (28°F), first in fall, 50% chance before
October 16

The last 15 years (2006–2020 normals)

Typical last frost May 20 (2 days earlier than the 30-year normal), typical first fall frost October 5 (3 days later). Frost-free season 136 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 Onaway: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 2, 20% May 30, 30% May 27, 40% May 24, 50% May 22, 60% May 19, 70% May 15, 80% May 11, 90% May 3. Observed last spring frost in recent years: 2021 May 30.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 2May 22May 32021: May 30Fall at Onaway: chance of a frost before this dateFall, chance of a frost before the date: 10% September 16, 20% September 21, 30% September 25, 40% September 29, 50% October 2, 60% October 5, 70% October 8, 80% October 12, 90% October 16. Observed first fall frost in recent years: 2021 October 23.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 16Oct 2Oct 162021: October 23
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 23
2022incomplete recordincomplete record
2023incomplete recordincomplete record
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

September 16 marks the cautious fall date in Onaway for finishing the harvest, with only a 10 % chance that a light frost has arrived earlier. In spring the cautious date for setting out tender crops is June 2, while in fall the cautious date to end harvesting tender crops is September 16.

The 50 % light-frost date in spring is May 22; there is a 50 % chance of a light frost later than this date. The 50 % light-frost date in fall is October 2; there is a 50 % chance of a light frost earlier than this date. The hard-frost 50 % dates are May 7 and October 16, indicating a 50 % chance of a hard frost later (spring) or earlier (fall). Hard frost at 28 °F matters more than light frost at 32 °F because it can kill tender plant tissue rather than merely chill it.

How to read the probabilities

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

  • Spring: "10% after June 2" 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 Onaway, MINumbered nearest stations: 1 — Vanderbilt, MI — 20 mi; 2 — Cheboygan, MI — 21 mi; 3 — Pellston, MI — 30 mi; 4 — Gaylord, MI — 35 mi; 5 — Petoskey, MI — 37 mi.25 mi · 40 km1. Vanderbilt, MI — 20 mi12. Cheboygan, MI — 21 mi23. Pellston, MI — 30 mi34. Gaylord, MI — 35 mi45. Petoskey, MI — 37 mi5
  1. Vanderbilt, MI 20 mi (32 km)
  2. Cheboygan, MI 21 mi (33 km)
  3. Pellston, MI 30 mi (48 km)
  4. Gaylord, MI 35 mi (57 km)
  5. Petoskey, 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: 45.4108, -84.2233.