U.S. Frost Dates by Weather Station

NOAA station USC00214106 · Minnesota

Frost Dates for Itasca University of Minn, MN

NOAA weather station Itasca University of Minn (USC00214106), Minnesota · elevation 1490 ft (454 m) · hardiness zone 3b*

  • Lower-risk planting dateafter May 31only 1 spring in 10 still has a frost later
  • Typical last frostMay 1850% chance of a frost after it
  • Typical first fall frostSeptember 2750% chance of a frost before it
  • Frost-free season130 daystypical year, 32°F
  • Hardiness zone3bcalculated*

The year at a glance

Frost season at Itasca University of Minn, MNSpring: a frost after May 3 in 9 years out of 10, after May 18 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 12 in 1 year out of 10, before September 27 in half of the years, before October 10 in 9 years out of 10. Typical frost-free season: 130 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 18First frost ~Sep 27Frost season at Itasca University of Minn, MNSpring: a frost after May 3 in 9 years out of 10, after May 18 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 12 in 1 year out of 10, before September 27 in half of the years, before October 10 in 9 years out of 10. Typical frost-free season: 130 days.JFMAMJJASONDLast frost ~May 18First frost ~Sep 27
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 31September 12
50% (typical)May 18September 27
90% (likely)May 3October 10
Frost-free season (32°F, 50% chance)
130 days
Hard frost (28°F), last in spring, 50% chance after
May 6
Hard frost (28°F), first in fall, 50% chance before
October 8

The last 15 years (2006–2020 normals)

Typical last frost May 19 (1 day later than the 30-year normal), typical first fall frost September 29 (2 days later). Frost-free season 132 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 Itasca University of Minn: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 31, 20% May 28, 30% May 24, 40% May 21, 50% May 18, 60% May 15, 70% May 11, 80% May 8, 90% May 3. Observed last spring frost in recent years: 2021 May 29, 2022 May 22, 2023 May 4, 2024 April 24, 2025 April 29, 2026 May 21.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 31May 18May 32021: May 292022: May 222023: May 42024: April 242025: April 292026: May 21Fall at Itasca University of Minn: chance of a frost before this dateFall, chance of a frost before the date: 10% September 12, 20% September 18, 30% September 21, 40% September 24, 50% September 27, 60% September 30, 70% October 1, 80% October 5, 90% October 10. Observed first fall frost in recent years: 2021 October 17, 2022 September 27, 2023 October 8, 2024 October 13, 2025 October 7.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 12Sep 27Oct 102021: October 172022: September 272023: October 82024: October 132025: October 7
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 17
2022May 22September 27
2023May 4October 8
2024April 24October 13
2025April 29October 7
2026May 21season not over yet

What these dates mean

May 31, the cautious spring date with a 10 % chance of a later light frost, lets a gardener plan to set out tender crops. The 50% date in spring is May 18, indicating an even chance of a light frost occurring later, while the 50% date in fall is September 27, indicating an even chance of a light frost occurring earlier. The hard-frost 50% dates are May 6 and October 8, marking the median odds for a 28 °F event.

September 12, the cautious fall date with a 10 % chance of an earlier light frost, guides a gardener to finish harvesting tender crops. A hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, so it is a more critical threshold for the growing season.

How to read the probabilities

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

  • Spring: "10% after May 31" 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 12" 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 Itasca University of Minn, MNNumbered nearest stations: 1 — Park Rapids, MN — 23 mi; 2 — Cass Lake, MN — 29 mi; 3 — Leech Lake, MN — 45 mi; 4 — near Crosslake, MN — 64 mi; 5 — Red Lake Falls, MN — 68 mi.25 mi · 40 km1. Park Rapids, MN — 23 mi12. Cass Lake, MN — 29 mi23. Leech Lake, MN — 45 mi34. near Crosslake, MN — 64 mi45. Red Lake Falls, MN — 68 mi5
  1. Park Rapids, MN 23 mi (37 km)
  2. Cass Lake, MN 29 mi (47 km)
  3. Leech Lake, MN 45 mi (73 km)
  4. near Crosslake, MN 64 mi (103 km)
  5. Red Lake Falls, MN 68 mi (110 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: 47.2256, -95.1919.