U.S. Frost Dates by Weather Station

NOAA station USW00014992 · Minnesota

Frost Dates for Redwood Falls, MN

NOAA weather station Redwood Falls Municipal Airport (USW00014992), Minnesota · elevation 1021 ft (311 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 14only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 450% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Redwood Falls, MNSpring: a frost after April 16 in 9 years out of 10, after April 30 in half of the years, after May 14 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 4Frost season at Redwood Falls, MNSpring: a frost after April 16 in 9 years out of 10, after April 30 in half of the years, after May 14 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 4
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 14September 21
50% (typical)April 30October 4
90% (likely)April 16October 18
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 20
Hard frost (28°F), first in fall, 50% chance before
October 15

The last 15 years (2006–2020 normals)

Typical last frost April 30 (same as the 30-year normal), typical first fall frost October 8 (4 days later). Frost-free season 161 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 Redwood Falls: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 14, 20% May 9, 30% May 5, 40% May 3, 50% April 30, 60% April 28, 70% April 25, 80% April 21, 90% April 16. Observed last spring frost in recent years: 2021 May 11, 2022 April 27, 2023 April 25, 2024 April 21, 2025 April 19, 2026 May 5.Spring: last frostChance of a frost after this date10%50%90%May 1May 14Apr 30Apr 162021: May 112022: April 272023: April 252024: April 212025: April 192026: May 5Fall at Redwood Falls: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 27, 30% September 30, 40% October 2, 50% October 4, 60% October 7, 70% October 10, 80% October 14, 90% October 18. Observed first fall frost in recent years: 2021 October 23, 2022 September 28, 2023 October 10, 2024 October 15, 2025 October 8.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 21Oct 4Oct 182021: October 232022: September 282023: October 102024: October 152025: October 8
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 27September 28
2023April 25October 10
2024April 21October 15
2025April 19October 8
2026May 5season not over yet

What these dates mean

May 14, which carries a 10 % chance of a later light frost, is the cautious spring date that lets a gardener plan to set out tender crops with low risk.

The 50 % dates—April 30 in spring and October 4 in fall—represent the point where odds of a light frost are even; a gardener can treat them as a midpoint of risk. The 50 % hard-frost dates are April 20 and October 15, and a hard frost at 28 °F can injure plants that would survive a 32 °F light frost.

September 21, with only a 10 % chance that a light frost has already arrived, is the cautious fall date for finishing harvest of tender crops, while October 18 carries a 90 % chance and is a gamble.

How to read the probabilities

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

  • Spring: "10% after May 14" 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 21" 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 Redwood Falls, MNNumbered nearest stations: 1 — Lamberton SW Research & Outreach C, MN — 24 mi; 2 — Tracy, MN — 35 mi; 3 — Marshall, MN — 35 mi; 4 — Gaylord, MN — 42 mi; 5 — Saint James, MN — 45 mi.MN25 mi · 40 km1. Lamberton SW Research & Outreach C, MN — 24 mi12. Tracy, MN — 35 mi23. Marshall, MN — 35 mi34. Gaylord, MN — 42 mi45. Saint James, MN — 45 mi5
  1. Lamberton SW Research & Outreach C, MN 24 mi (39 km)
  2. Tracy, MN 35 mi (56 km)
  3. Marshall, MN 35 mi (57 km)
  4. Gaylord, MN 42 mi (68 km)
  5. Saint James, MN 45 mi (72 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: 44.5483, -95.0803.