U.S. Frost Dates by Weather Station

NOAA station USC00214652 · Minnesota

Frost Dates for Leech Lake, MN

NOAA weather station Leech Lake (USC00214652), Minnesota · elevation 1302 ft (397 m) · hardiness zone 3b*

  • Lower-risk planting dateafter May 23only 1 spring in 10 still has a frost later
  • Typical last frostMay 850% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season144 daystypical year, 32°F
  • Hardiness zone3bcalculated*

The year at a glance

Frost season at Leech Lake, MNSpring: a frost after April 28 in 9 years out of 10, after May 8 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 144 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 8First frost ~Oct 1Frost season at Leech Lake, MNSpring: a frost after April 28 in 9 years out of 10, after May 8 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 144 days.JFMAMJJASONDLast frost ~May 8First frost ~Oct 1
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.Today

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 23September 19
50% (typical)May 8October 1
90% (likely)April 28October 17
Frost-free season (32°F, 50% chance)
144 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 15

The last 15 years (2006–2020 normals)

Typical last frost May 7 (1 day earlier than the 30-year normal), typical first fall frost October 6 (5 days later). Frost-free season 148 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 Leech Lake: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 23, 20% May 18, 30% May 15, 40% May 11, 50% May 8, 60% May 6, 70% May 4, 80% May 1, 90% April 28. Observed last spring frost in recent years: 2021 May 29, 2022 May 5, 2023 May 4, 2024 April 25, 2025 April 30, 2026 May 11.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 23May 8Apr 282021: May 292022: May 52023: May 42024: April 252025: April 302026: May 11Fall at Leech Lake: chance of a frost before this dateFall, chance of a frost before the date: 10% September 19, 20% September 23, 30% September 26, 40% September 30, 50% October 1, 60% October 5, 70% October 7, 80% October 11, 90% October 17. Observed first fall frost in recent years: 2021 October 21, 2022 September 28, 2023 October 10, 2024 October 8, 2025 October 8.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 19Oct 1Oct 172021: October 212022: September 282023: October 102024: October 82025: 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 29October 21
2022May 5September 28
2023May 4October 10
2024April 25October 8
2025April 30October 8
2026May 11season not over yet

What these dates mean

The 144 days between the 50% dates in Leech Lake, May 8 and October 1, mark the period when a light frost (32 °F) is as likely as not; these dates are median points, not frost dates, and give gardeners a sense of the central window for tender-crop activity.

For a cautious spring plan, the station’s 10 % chance date, May 23, is used to set out tender crops, while planting on April 28 carries a 90 % chance of a frost and is a gamble. In the fall, the cautious date to finish harvesting tender crops is September 19, when there is only a 10 % chance a frost has already arrived; waiting until October 17 involves a 90 % chance of an early frost and is risky. The hard-frost median dates are April 30 and October 15, and a hard frost at 28 °F can damage plant tissue 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 23" 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 19" 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 Leech Lake, MNNumbered nearest stations: 1 — Cass Lake, MN — 21 mi; 2 — near Grand Rapids, MN — 34 mi; 3 — near Crosslake, MN — 40 mi; 4 — Itasca University of Minn, MN — 45 mi; 5 — Park Rapids, MN — 46 mi.MN25 mi · 40 km1. Cass Lake, MN — 21 mi12. near Grand Rapids, MN — 34 mi23. near Crosslake, MN — 40 mi34. Itasca University of Minn, MN — 45 mi45. Park Rapids, MN — 46 mi5
  1. Cass Lake, MN 21 mi (33 km)
  2. near Grand Rapids, MN 34 mi (55 km)
  3. near Crosslake, MN 40 mi (65 km)
  4. Itasca University of Minn, MN 45 mi (73 km)
  5. Park Rapids, MN 46 mi (75 km)

Sources

* Hardiness zone 3b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 47.2467, -94.2228.