U.S. Frost Dates by Weather Station

NOAA station USC00215204 · Minnesota

Frost Dates for Marshall, MN

NOAA weather station Marshall (USC00215204), Minnesota · elevation 1149 ft (350 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 18only 1 spring in 10 still has a frost later
  • Typical last frostMay 550% chance of a frost after it
  • Typical first fall frostOctober 350% chance of a frost before it
  • Frost-free season150 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Marshall, MNSpring: a frost after April 21 in 9 years out of 10, after May 5 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 150 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 5First frost ~Oct 3Frost season at Marshall, MNSpring: a frost after April 21 in 9 years out of 10, after May 5 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 150 days.JFMAMJJASONDLast frost ~May 5First frost ~Oct 3
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 18September 21
50% (typical)May 5October 3
90% (likely)April 21October 17
Frost-free season (32°F, 50% chance)
150 days
Hard frost (28°F), last in spring, 50% chance after
April 27
Hard frost (28°F), first in fall, 50% chance before
October 13

The last 15 years (2006–2020 normals)

Typical last frost May 4 (1 day earlier than the 30-year normal), typical first fall frost October 9 (6 days later). Frost-free season 157 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 Marshall: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 18, 20% May 13, 30% May 10, 40% May 7, 50% May 5, 60% May 2, 70% April 30, 80% April 27, 90% April 21. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 April 26, 2024 April 21, 2025 April 29, 2026 May 5.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 18May 5Apr 212021: May 112022: April 282023: April 262024: April 212025: April 292026: May 5Fall at Marshall: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 25, 30% September 28, 40% October 1, 50% October 3, 60% October 6, 70% October 9, 80% October 12, 90% October 17. Observed first fall frost in recent years: 2021 October 23, 2022 September 28, 2023 October 11, 2024 October 14, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 21Oct 3Oct 172021: October 232022: September 282023: October 112024: October 142025: 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 28September 28
2023April 26October 11
2024April 21October 14
2025April 29October 22
2026May 5season not over yet

What these dates mean

The 150 days between the 32°F 50% dates of May 5 and October 3 in Marshall frame the period when tender crops can be grown without a light-frost risk. The 50% dates themselves indicate an even chance of a light frost occurring later (spring) or earlier (fall), so they mark the central point of the frost-free window for this station.

For a cautious plan, spring planting should wait until the May 18 date, which carries a 10 % chance of a later light frost, while fall harvesting should be finished by September 21, the date with a 10 % chance of an earlier light frost. A hard frost at 28°F can damage plants that survive a 32°F light frost, making the median hard-frost dates of April 27 and October 13 important reference points 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 18" 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 Marshall, MNNumbered nearest stations: 1 — Tracy, MN — 18 mi; 2 — Lamberton SW Research & Outreach C, MN — 28 mi; 3 — Canby, MN — 29 mi; 4 — Lake Wilson, MN — 34 mi; 5 — Redwood Falls, MN — 35 mi.SD25 mi · 40 km1. Tracy, MN — 18 mi12. Lamberton SW Research & Outreach C, MN — 28 mi23. Canby, MN — 29 mi34. Lake Wilson, MN — 34 mi45. Redwood Falls, MN — 35 mi5
  1. Tracy, MN 18 mi (29 km)
  2. Lamberton SW Research & Outreach C, MN 28 mi (46 km)
  3. Canby, MN 29 mi (47 km)
  4. Lake Wilson, MN 34 mi (54 km)
  5. Redwood Falls, MN 35 mi (57 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: 44.4717, -95.7903.