U.S. Frost Dates by Weather Station

NOAA station USC00218323 · Minnesota

Frost Dates for Tracy, MN

NOAA weather station Tracy (USC00218323), Minnesota · elevation 1403 ft (428 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 15only 1 spring in 10 still has a frost later
  • Typical last frostMay 250% chance of a frost after it
  • Typical first fall frostOctober 550% chance of a frost before it
  • Frost-free season156 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Tracy, MNSpring: a frost after April 18 in 9 years out of 10, after May 2 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 5 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 156 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 2First frost ~Oct 5Frost season at Tracy, MNSpring: a frost after April 18 in 9 years out of 10, after May 2 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 5 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 156 days.JFMAMJJASONDLast frost ~May 2First frost ~Oct 5
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 15September 22
50% (typical)May 2October 5
90% (likely)April 18October 20
Frost-free season (32°F, 50% chance)
156 days
Hard frost (28°F), last in spring, 50% chance after
April 23
Hard frost (28°F), first in fall, 50% chance before
October 15

The last 15 years (2006–2020 normals)

Typical last frost May 2 (same as the 30-year normal), typical first fall frost October 9 (4 days later). Frost-free season 160 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 Tracy: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 15, 20% May 10, 30% May 6, 40% May 4, 50% May 2, 60% April 30, 70% April 27, 80% April 23, 90% April 18. Observed last spring frost in recent years: 2021 May 11, 2022 May 4, 2023 April 25, 2024 April 24, 2025 April 29, 2026 May 2.Spring: last frostChance of a frost after this date10%50%90%May 1May 15May 2Apr 182021: May 112022: May 42023: April 252024: April 242025: April 292026: May 2Fall at Tracy: chance of a frost before this dateFall, chance of a frost before the date: 10% September 22, 20% September 27, 30% September 30, 40% October 3, 50% October 5, 60% October 8, 70% October 12, 80% October 15, 90% October 20. Observed first fall frost in recent years: 2021 October 23, 2022 October 8, 2023 October 27, 2024 October 15, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 22Oct 5Oct 202021: October 232022: October 82023: October 272024: October 152025: 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
2022May 4October 8
2023April 25October 27
2024April 24October 15
2025April 29October 22
2026May 2season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Tracy is September 22, when there is only a 10 % chance that a light frost has arrived earlier.

The 50 % light-frost dates, May 2 in spring and October 5 in fall, mark the point at which a gardener has an even chance of a frost occurring later (spring) or earlier (fall); they are not frost dates themselves. For tender crops the cautious spring date is May 15, which carries a 10 % chance of a frost later, while the cautious fall date, already noted, is September 22. The median hard-frost dates are April 23 and October 15, and a hard frost at 28 °F can injure plants that would survive a 32 °F light frost, making it a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 15" 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 22" 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 Tracy, MNNumbered nearest stations: 1 — Lamberton SW Research & Outreach C, MN — 16 mi; 2 — Marshall, MN — 18 mi; 3 — Lake Wilson, MN — 23 mi; 4 — Redwood Falls, MN — 35 mi; 5 — Windom, MN — 36 mi.SDIA25 mi · 40 km1. Lamberton SW Research & Outreach C, MN — 16 mi12. Marshall, MN — 18 mi23. Lake Wilson, MN — 23 mi34. Redwood Falls, MN — 35 mi45. Windom, MN — 36 mi5
  1. Lamberton SW Research & Outreach C, MN 16 mi (25 km)
  2. Marshall, MN 18 mi (29 km)
  3. Lake Wilson, MN 23 mi (37 km)
  4. Redwood Falls, MN 35 mi (56 km)
  5. Windom, MN 36 mi (58 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: 44.2394, -95.6308.