U.S. Frost Dates by Weather Station

NOAA station USC00219033 · Minnesota

Frost Dates for Windom, MN

NOAA weather station Windom (USC00219033), Minnesota · elevation 1384 ft (422 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 13only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 1050% chance of a frost before it
  • Frost-free season162 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Windom, MNSpring: a frost after April 15 in 9 years out of 10, after April 30 in half of the years, after May 13 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 10 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 162 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 10Frost season at Windom, MNSpring: a frost after April 15 in 9 years out of 10, after April 30 in half of the years, after May 13 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 10 in half of the years, before October 24 in 9 years out of 10. Typical frost-free season: 162 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 10
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 13September 25
50% (typical)April 30October 10
90% (likely)April 15October 24
Frost-free season (32°F, 50% chance)
162 days
Hard frost (28°F), last in spring, 50% chance after
April 19
Hard frost (28°F), first in fall, 50% chance before
October 21

The last 15 years (2006–2020 normals)

Typical last frost April 28 (2 days earlier than the 30-year normal), typical first fall frost October 13 (3 days later). Frost-free season 168 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 Windom: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 13, 20% May 8, 30% May 4, 40% May 2, 50% April 30, 60% April 27, 70% April 24, 80% April 21, 90% April 15. Observed last spring frost in recent years: 2021 May 11, 2022 April 27, 2023 April 26, 2024 April 5, 2025 April 19, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 13Apr 30Apr 152021: May 112022: April 272023: April 262024: April 52025: April 192026: April 20Fall at Windom: chance of a frost before this dateFall, chance of a frost before the date: 10% September 25, 20% September 29, 30% October 3, 40% October 6, 50% October 10, 60% October 13, 70% October 16, 80% October 20, 90% October 24. Observed first fall frost in recent years: 2021 October 23, 2022 October 8, 2023 October 28, 2024 October 15, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 25Oct 10Oct 242021: October 232022: October 82023: October 282024: October 152025: October 22
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 23
2022April 27October 8
2023April 26October 28
2024April 5October 15
2025April 19October 22
2026April 20season not over yet

What these dates mean

September 25 is the cautious fall date to finish harvesting tender crops in Windom, because only a 10 % chance of a light frost has occurred earlier.

The 50% spring light-frost date is April 30, meaning a 50 % chance of a frost later than this date, and the 50% fall light-frost date is October 10, meaning a 50 % chance of a frost earlier than this date. For a cautious planting plan, the spring date to set out tender crops is May 13 (10 % chance of a frost later), while the fall date to end the harvest is September 25 (10 % chance of a frost earlier).

Hard frost, measured at 28 °F, is more damaging than a light frost at 32 °F, so the 50% hard-frost dates—April 19 in spring and October 21 in fall—signal a critical temperature threshold for gardeners.

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 September 25" 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 Windom, MNNumbered nearest stations: 1 — Saint James, MN — 26 mi; 2 — Lamberton SW Research & Outreach C, MN — 27 mi; 3 — Worthington, MN — 28 mi; 4 — Lake Park, IA — 31 mi; 5 — Milford, IA — 34 mi.MNIASD25 mi · 40 km1. Saint James, MN — 26 mi12. Lamberton SW Research & Outreach C, MN — 27 mi23. Worthington, MN — 28 mi34. Lake Park, IA — 31 mi45. Milford, IA — 34 mi5
  1. Saint James, MN 26 mi (42 km)
  2. Lamberton SW Research & Outreach C, MN 27 mi (43 km)
  3. Worthington, MN 28 mi (45 km)
  4. Lake Park, IA 31 mi (51 km)
  5. Milford, IA 34 mi (55 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: 43.8769, -95.1158.