U.S. Frost Dates by Weather Station

NOAA station USW00014845 · Michigan

Frost Dates near Saginaw, MI

NOAA weather station Saginaw MBS International Airport (USW00014845), Michigan · elevation 660 ft (201 m) · hardiness zone 6a*

Saginaw is the nearest town to the station (10.2 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter May 13only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 1750% chance of a frost before it
  • Frost-free season172 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Saginaw, MISpring: a frost after April 13 in 9 years out of 10, after April 26 in half of the years, after May 13 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 17 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 172 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 17Frost season near Saginaw, MISpring: a frost after April 13 in 9 years out of 10, after April 26 in half of the years, after May 13 in 1 year out of 10. Fall: the first frost comes before October 2 in 1 year out of 10, before October 17 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 172 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 17
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 13October 2
50% (typical)April 26October 17
90% (likely)April 13October 31
Frost-free season (32°F, 50% chance)
172 days
Hard frost (28°F), last in spring, 50% chance after
April 15
Hard frost (28°F), first in fall, 50% chance before
October 31

The last 15 years (2006–2020 normals)

Typical last frost April 28 (2 days later than the 30-year normal), typical first fall frost October 22 (5 days later). Frost-free season 176 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 near Saginaw: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 13, 20% May 7, 30% May 3, 40% April 29, 50% April 26, 60% April 23, 70% April 21, 80% April 17, 90% April 13. Observed last spring frost in recent years: 2021 May 11, 2022 April 29, 2023 April 27, 2024 April 26, 2025 April 30, 2026 May 2.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 13Apr 26Apr 132021: May 112022: April 292023: April 272024: April 262025: April 302026: May 2Fall near Saginaw: chance of a frost before this dateFall, chance of a frost before the date: 10% October 2, 20% October 7, 30% October 11, 40% October 14, 50% October 17, 60% October 20, 70% October 23, 80% October 26, 90% October 31. Observed first fall frost in recent years: 2021 October 24, 2022 October 8, 2023 October 23, 2024 October 17, 2025 October 26.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 2Oct 17Oct 312021: October 242022: October 82023: October 232024: October 172025: October 26
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 11October 24
2022April 29October 8
2023April 27October 23
2024April 26October 17
2025April 30October 26
2026May 2season not over yet

What these dates mean

The 172 days between the 32°F 50% dates in the Saginaw area—April 26 in spring and October 17 in fall—define the central window in which light frost is equally likely to have occurred or not. For a gardener these median dates are not frost thresholds but simply reference points that split the risk of a 32°F frost.

The cautious plan for tender crops follows the 10 % dates: May 13, when there is only a 10 % chance of a light frost later, is used for setting out seedlings, and October 2, with a 10 % chance of a light frost earlier, marks the final date for finishing harvests. The 28°F hard-frost median dates are April 15 and October 31; a hard frost matters more because 28°F can damage plants that would otherwise 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 13" 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 2" 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 Saginaw, MINumbered nearest stations: 1 — Midland, MI — 8 mi; 2 — Standish, MI — 34 mi; 3 — Owosso, MI — 36 mi; 4 — Gladwin, MI — 37 mi; 5 — West Branch, MI — 50 mi.25 mi · 40 km1. Midland, MI — 8 mi12. Standish, MI — 34 mi23. Owosso, MI — 36 mi34. Gladwin, MI — 37 mi45. West Branch, MI — 50 mi5
  1. Midland, MI 8 mi (13 km)
  2. Standish, MI 34 mi (55 km)
  3. Owosso, MI 36 mi (58 km)
  4. Gladwin, MI 37 mi (59 km)
  5. West Branch, MI 50 mi (81 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 43.5331, -84.0797.