U.S. Frost Dates by Weather Station

NOAA station USC00216822 · Minnesota

Frost Dates near Red Wing, MN

NOAA weather station Red Wing Dam 3 (USC00216822), Minnesota · elevation 677 ft (206 m) · hardiness zone 4b*

Red Wing is the nearest town to the station (5.0 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 7only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 1450% chance of a frost before it
  • Frost-free season173 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season near Red Wing, MNSpring: a frost after April 8 in 9 years out of 10, after April 23 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 14 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 173 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 14Frost season near Red Wing, MNSpring: a frost after April 8 in 9 years out of 10, after April 23 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 14 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 173 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 14
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 7September 28
50% (typical)April 23October 14
90% (likely)April 8October 28
Frost-free season (32°F, 50% chance)
173 days
Hard frost (28°F), last in spring, 50% chance after
April 12
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost April 23 (same as the 30-year normal), typical first fall frost October 19 (5 days later). Frost-free season 178 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 Red Wing: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 7, 20% May 2, 30% April 30, 40% April 27, 50% April 23, 60% April 20, 70% April 17, 80% April 14, 90% April 8. Observed last spring frost in recent years: 2021 May 12, 2022 April 28, 2023 April 26, 2024 April 22, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 7Apr 23Apr 82021: May 122022: April 282023: April 262024: April 222025: April 92026: April 21Fall near Red Wing: chance of a frost before this dateFall, chance of a frost before the date: 10% September 28, 20% October 3, 30% October 7, 40% October 11, 50% October 14, 60% October 17, 70% October 20, 80% October 23, 90% October 28. Observed first fall frost in recent years: 2021 October 22, 2022 October 8, 2023 October 28, 2024 October 16, 2025 October 23.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 28Oct 14Oct 282021: October 222022: October 82023: October 282024: October 162025: 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 12October 22
2022April 28October 8
2023April 26October 28
2024April 22October 16
2025April 9October 23
2026April 21season not over yet

What these dates mean

Planting tender crops on April 8 in the Red Wing area is a gamble; there is a 90% chance that a light frost will still occur later in the season. The later spring date of May 7 is the cautious date, offering only a 10% chance of a frost after that day.

For the autumn harvest, September 28 serves as the cautious date, with just a 10% chance that a light frost has arrived earlier. The median dates, April 23 in spring and October 14 in fall, each represent a 50% chance of a frost occurring on either side of the date; they are not themselves frost dates. The hard-frost median dates are April 12 and October 25, marking the point at which a 28 °F temperature is equally likely to have happened.

A hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so those dates warrant special attention.

How to read the probabilities

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

  • Spring: "10% after May 7" 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 28" 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 Red Wing, MNNumbered nearest stations: 1 — Ellsworth, WI — 11 mi; 2 — near Hastings, MN — 16 mi; 3 — River Falls, WI — 17 mi; 4 — Zumbrota, MN — 22 mi; 5 — Rosemount, MN — 25 mi.MNWI25 mi · 40 km1. Ellsworth, WI — 11 mi12. near Hastings, MN — 16 mi23. River Falls, WI — 17 mi34. Zumbrota, MN — 22 mi45. Rosemount, MN — 25 mi5
  1. Ellsworth, WI 11 mi (18 km)
  2. near Hastings, MN 16 mi (26 km)
  3. River Falls, WI 17 mi (27 km)
  4. Zumbrota, MN 22 mi (35 km)
  5. Rosemount, MN 25 mi (40 km)

Sources

* Hardiness zone 4b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 44.6103, -92.61.