U.S. Frost Dates by Weather Station

NOAA station USC00210355 · Minnesota

Frost Dates for Austin, MN

NOAA weather station Austin Waste WTP Facility (USC00210355), Minnesota · elevation 1199 ft (366 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 550% chance of a frost before it
  • Frost-free season158 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Austin, MNSpring: a frost after April 14 in 9 years out of 10, after April 30 in half of the years, after May 11 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 19 in 9 years out of 10. Typical frost-free season: 158 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 5Frost season at Austin, MNSpring: a frost after April 14 in 9 years out of 10, after April 30 in half of the years, after May 11 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 19 in 9 years out of 10. Typical frost-free season: 158 days.JFMAMJJASONDLast frost ~Apr 30First 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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 11September 22
50% (typical)April 30October 5
90% (likely)April 14October 19
Frost-free season (32°F, 50% chance)
158 days
Hard frost (28°F), last in spring, 50% chance after
April 18
Hard frost (28°F), first in fall, 50% chance before
October 17

The last 15 years (2006–2020 normals)

Typical last frost May 1 (1 day later than the 30-year normal), typical first fall frost October 12 (7 days later). Frost-free season 165 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 Austin: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 7, 30% May 4, 40% May 2, 50% April 30, 60% April 27, 70% April 24, 80% April 20, 90% April 14. Observed last spring frost in recent years: 2021 May 12, 2022 April 28, 2023 May 3, 2024 April 23, 2025 April 16.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 11Apr 30Apr 142021: May 122022: April 282023: May 32024: April 232025: April 16Fall at Austin: chance of a frost before this dateFall, chance of a frost before the date: 10% September 22, 20% September 26, 30% September 30, 40% October 3, 50% October 5, 60% October 9, 70% October 12, 80% October 15, 90% October 19. Observed first fall frost in recent years: 2021 October 17, 2022 September 28, 2023 October 11, 2024 October 15, 2025 October 23.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 22Oct 5Oct 192021: October 172022: September 282023: October 112024: October 152025: October 23
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 12October 17
2022April 28September 28
2023May 3October 11
2024April 23October 15
2025April 16October 23
2026incomplete recordseason not over yet

What these dates mean

Planting tender crops on April 14 is a gamble, because a 90% chance of a light frost later than that date still exists in Austin.

The 50% date in spring is April 30, indicating an even odds chance of a light frost later. The 50% date in fall is October 5, indicating an even odds chance of a light frost earlier. A cautious spring plan would wait until May 11, when only a 10% chance of frost remains. A cautious fall plan would aim to finish tender crops by September 22, when there is only a 10% chance that a frost has already arrived.

Hard frost dates, with the 50% dates at April 18 and October 17, matter more because 28 °F can cause far more severe damage to plants 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 11" 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 Austin, MNNumbered nearest stations: 1 — Albert Lea, MN — 17 mi; 2 — Northwood, IA — 20 mi; 3 — Grand Meadow, MN — 21 mi; 4 — Osage, IA — 27 mi; 5 — Rochester, MN — 30 mi.MNIAWI25 mi · 40 km1. Albert Lea, MN — 17 mi12. Northwood, IA — 20 mi23. Grand Meadow, MN — 21 mi34. Osage, IA — 27 mi45. Rochester, MN — 30 mi5
  1. Albert Lea, MN 17 mi (27 km)
  2. Northwood, IA 20 mi (31 km)
  3. Grand Meadow, MN 21 mi (33 km)
  4. Osage, IA 27 mi (44 km)
  5. Rochester, MN 30 mi (48 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: 43.6542, -92.9739.