U.S. Frost Dates by Weather Station

NOAA station USC00214778 · Minnesota

Frost Dates for Litchfield, MN

NOAA weather station Litchfield (USC00214778), Minnesota · elevation 1120 ft (341 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 22only 1 spring in 10 still has a frost later
  • Typical last frostMay 650% chance of a frost after it
  • Typical first fall frostOctober 250% chance of a frost before it
  • Frost-free season147 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Litchfield, MNSpring: a frost after April 23 in 9 years out of 10, after May 6 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 2 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 147 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 6First frost ~Oct 2Frost season at Litchfield, MNSpring: a frost after April 23 in 9 years out of 10, after May 6 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 2 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 147 days.JFMAMJJASONDLast frost ~May 6First frost ~Oct 2
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 22September 20
50% (typical)May 6October 2
90% (likely)April 23October 15
Frost-free season (32°F, 50% chance)
147 days
Hard frost (28°F), last in spring, 50% chance after
April 27
Hard frost (28°F), first in fall, 50% chance before
October 10

The last 15 years (2006–2020 normals)

Typical last frost May 5 (1 day earlier than the 30-year normal), typical first fall frost October 8 (6 days later). Frost-free season 155 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 Litchfield: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 22, 20% May 15, 30% May 11, 40% May 8, 50% May 6, 60% May 3, 70% April 30, 80% April 27, 90% April 23. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 April 27, 2024 April 21, 2025 April 11, 2026 May 8.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 22May 6Apr 232021: May 112022: April 282023: April 272024: April 212025: April 112026: May 8Fall at Litchfield: chance of a frost before this dateFall, chance of a frost before the date: 10% September 20, 20% September 24, 30% September 26, 40% September 29, 50% October 2, 60% October 5, 70% October 7, 80% October 10, 90% October 15. Observed first fall frost in recent years: 2021 October 21, 2022 September 27, 2023 October 9, 2024 October 14.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 20Oct 2Oct 152021: October 212022: September 272023: October 92024: October 14
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 21
2022April 28September 27
2023April 27October 9
2024April 21October 14
2025April 11incomplete record
2026May 8season not over yet

What these dates mean

The 147 days between the 50% light-frost dates in Litchfield—May 6 and October 2—frame the period in which a light frost is equally likely to arrive later in spring or earlier in fall. For a gardener this median window defines the central portion of the growing season under the 28-year record.

A cautious planting schedule would wait until the spring cautious date of May 22, which carries only a 10 % chance of a light frost later, and would aim to finish tender crops by the fall cautious date of September 20, which carries only a 10 % chance of a light frost earlier. The 50% light-frost dates—May 6 and October 2—represent an even chance of a light frost. The hard-frost median dates are April 27 and October 10, and a hard frost at 28 °F can injure plants more severely than a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after May 22" 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 20" 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 Litchfield, MNNumbered nearest stations: 1 — near Collegeville, MN — 32 mi; 2 — Saint Cloud, MN — 37 mi; 3 — Gaylord, MN — 42 mi; 4 — Santiago, MN — 48 mi; 5 — Redwood Falls, MN — 48 mi.WI25 mi · 40 km1. near Collegeville, MN — 32 mi12. Saint Cloud, MN — 37 mi23. Gaylord, MN — 42 mi34. Santiago, MN — 48 mi45. Redwood Falls, MN — 48 mi5
  1. near Collegeville, MN 32 mi (51 km)
  2. Saint Cloud, MN 37 mi (60 km)
  3. Gaylord, MN 42 mi (68 km)
  4. Santiago, MN 48 mi (77 km)
  5. Redwood Falls, MN 48 mi (77 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: 45.1278, -94.5347.