U.S. Frost Dates by Weather Station

NOAA station USW00094931 · Minnesota

Frost Dates near Hibbing, MN

NOAA weather station Hibbing Chisholm Hibbing Airport (USW00094931), Minnesota · elevation 1352 ft (412 m) · hardiness zone 3b*

Hibbing is the nearest town to the station (5.4 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter June 25only 1 spring in 10 still has a frost later
  • Typical last frostJune 550% chance of a frost after it
  • Typical first fall frostSeptember 850% chance of a frost before it
  • Frost-free season93 daystypical year, 32°F
  • Hardiness zone3bcalculated*

The year at a glance

Frost season near Hibbing, MNSpring: a frost after May 22 in 9 years out of 10, after June 5 in half of the years, after June 25 in 1 year out of 10. Fall: the first frost comes before August 23 in 1 year out of 10, before September 8 in half of the years, before September 23 in 9 years out of 10. Typical frost-free season: 93 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Jun 5First frost ~Sep 8Frost season near Hibbing, MNSpring: a frost after May 22 in 9 years out of 10, after June 5 in half of the years, after June 25 in 1 year out of 10. Fall: the first frost comes before August 23 in 1 year out of 10, before September 8 in half of the years, before September 23 in 9 years out of 10. Typical frost-free season: 93 days.JFMAMJJASONDLast frost ~Jun 5First frost ~Sep 8
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)June 25August 23
50% (typical)June 5September 8
90% (likely)May 22September 23
Frost-free season (32°F, 50% chance)
93 days
Hard frost (28°F), last in spring, 50% chance after
May 23
Hard frost (28°F), first in fall, 50% chance before
September 21

The last 15 years (2006–2020 normals)

Typical last frost June 6 (1 day later than the 30-year normal), typical first fall frost September 6 (2 days earlier). Frost-free season 92 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 near Hibbing: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 25, 20% June 17, 30% June 12, 40% June 8, 50% June 5, 60% June 2, 70% May 30, 80% May 27, 90% May 22. Observed last spring frost in recent years: 2021 May 29, 2022 June 5, 2023 May 20, 2024 June 10, 2025 June 4, 2026 May 21.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jul 1Jun 25Jun 5May 222021: May 292022: June 52023: May 202024: June 102025: June 42026: May 21Fall near Hibbing: chance of a frost before this dateFall, chance of a frost before the date: 10% August 23, 20% August 29, 30% September 2, 40% September 5, 50% September 8, 60% September 12, 70% September 15, 80% September 19, 90% September 23. Observed first fall frost in recent years: 2021 September 6, 2022 September 22, 2023 September 12, 2024 September 7, 2025 September 6.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Aug 23Sep 8Sep 232021: September 62022: September 222023: September 122024: September 72025: September 6
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 29September 6
2022June 5September 22
2023May 20September 12
2024June 10September 7
2025June 4September 6
2026May 21season not over yet

What these dates mean

The 93 days between the 50% dates in the Hibbing area frame the period when light frosts are most uncertain. The 50% spring date is June 5 and the 50% fall date is September 8; each marks an even chance of a 32 °F frost occurring later in spring or earlier in fall, but they are not frost dates themselves.

Gardeners who prefer a low-risk schedule would wait until the cautious spring date of June 25 to set out tender crops, since only a 10 % chance of a later frost remains. In the fall the cautious date to finish harvesting tender crops is August 23, when there is only a 10 % chance that a frost has arrived earlier. The hard-frost 50% dates are May 23 and September 21, and a hard frost at 28 °F can damage 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 June 25" 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 August 23" 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 Hibbing, MNNumbered nearest stations: 1 — Eveleth, MN — 15 mi; 2 — Floodwood, MN — 29 mi; 3 — near Grand Rapids, MN — 32 mi; 4 — Wright, MN — 49 mi; 5 — Cloquet, MN — 49 mi.MNWI25 mi · 40 km1. Eveleth, MN — 15 mi12. Floodwood, MN — 29 mi23. near Grand Rapids, MN — 32 mi34. Wright, MN — 49 mi45. Cloquet, MN — 49 mi5
  1. Eveleth, MN 15 mi (25 km)
  2. Floodwood, MN 29 mi (46 km)
  3. near Grand Rapids, MN 32 mi (52 km)
  4. Wright, MN 49 mi (79 km)
  5. Cloquet, MN 49 mi (79 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: 47.3864, -92.8389.