U.S. Frost Dates by Weather Station

NOAA station USC00219072 · Minnesota

Frost Dates near Winona, MN

NOAA weather station Winona Dam 5 A (USC00219072), Minnesota · elevation 663 ft (202 m) · hardiness zone 5a*

Winona is the nearest town to the station (3.0 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 6only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 2150% chance of a frost before it
  • Frost-free season180 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season near Winona, MNSpring: a frost after April 7 in 9 years out of 10, after April 23 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 21 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 180 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 21Frost season near Winona, MNSpring: a frost after April 7 in 9 years out of 10, after April 23 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 7 in 1 year out of 10, before October 21 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 180 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 21
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)May 6October 7
50% (typical)April 23October 21
90% (likely)April 7November 4
Frost-free season (32°F, 50% chance)
180 days
Hard frost (28°F), last in spring, 50% chance after
April 11
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 21 (2 days earlier than the 30-year normal), typical first fall frost October 24 (3 days later). Frost-free season 185 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 Winona: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 6, 20% May 2, 30% April 29, 40% April 25, 50% April 23, 60% April 19, 70% April 16, 80% April 12, 90% April 7. Observed last spring frost in recent years: 2021 April 26, 2022 April 28, 2023 April 26, 2024 April 25, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 6Apr 23Apr 72021: April 262022: April 282023: April 262024: April 252025: April 92026: April 21Fall near Winona: chance of a frost before this dateFall, chance of a frost before the date: 10% October 7, 20% October 13, 30% October 16, 40% October 19, 50% October 21, 60% October 24, 70% October 27, 80% October 31, 90% November 4. Observed first fall frost in recent years: 2021 November 3, 2022 October 18, 2023 October 29, 2024 October 17, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 7Oct 21Nov 42021: November 32022: October 182023: October 292024: October 172025: October 25
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
2021April 26November 3
2022April 28October 18
2023April 26October 29
2024April 25October 17
2025April 9October 25
2026April 21season not over yet

What these dates mean

The 180 days between the 32°F 50% dates of April 23 and October 21 give Winona gardeners a seasonal window for planting, growing, and harvesting tender crops. Within that span the median light-frost dates mark the point at which a frost is equally likely to have occurred or not, so they are reference points rather than limits.

For a cautious plan the spring light-frost date of May 6 is used; it carries only a 10 % chance of a frost later, making it the recommended day to set out tender seedlings. In the fall the cautious date is October 7, which holds a 10 % chance of a frost earlier and therefore signals the latest time to finish harvesting tender crops.

The hard-frost median dates of April 11 and November 1 show when temperatures of 28 °F become as likely as not, and a hard frost can damage plants more severely than a light frost because it reaches a lower temperature that can freeze tissue.

How to read the probabilities

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

  • Spring: "10% after May 6" 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 7" 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 Winona, MNNumbered nearest stations: 1 — near Trempealeau, WI — 13 mi; 2 — Rushford, MN — 20 mi; 3 — near Alma, WI — 21 mi; 4 — La Crosse, WI — 25 mi; 5 — Theilman, MN — 29 mi.WIMN25 mi · 40 km1. near Trempealeau, WI — 13 mi12. Rushford, MN — 20 mi23. near Alma, WI — 21 mi34. La Crosse, WI — 25 mi45. Theilman, MN — 29 mi5
  1. near Trempealeau, WI 13 mi (21 km)
  2. Rushford, MN 20 mi (32 km)
  3. near Alma, WI 21 mi (33 km)
  4. La Crosse, WI 25 mi (41 km)
  5. Theilman, MN 29 mi (47 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: 44.0875, -91.6703.