U.S. Frost Dates by Weather Station

NOAA station USW00014839 · Wisconsin

Frost Dates near Milwaukee, WI

NOAA weather station Milwaukee Mitchell Airport (USW00014839), Wisconsin · elevation 670 ft (204 m) · hardiness zone 6a*

Milwaukee is the nearest town to the station (5.8 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 May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1950% chance of a frost after it
  • Typical first fall frostOctober 2950% chance of a frost before it
  • Frost-free season192 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Milwaukee, WISpring: a frost after April 6 in 9 years out of 10, after April 19 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before October 29 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 192 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 19First frost ~Oct 29Frost season near Milwaukee, WISpring: a frost after April 6 in 9 years out of 10, after April 19 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before October 29 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 192 days.JFMAMJJASONDLast frost ~Apr 19First frost ~Oct 29
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 2October 15
50% (typical)April 19October 29
90% (likely)April 6November 10
Frost-free season (32°F, 50% chance)
192 days
Hard frost (28°F), last in spring, 50% chance after
April 6
Hard frost (28°F), first in fall, 50% chance before
November 8

The last 15 years (2006–2020 normals)

Typical last frost April 16 (3 days earlier than the 30-year normal), typical first fall frost October 31 (2 days later). Frost-free season 196 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 Milwaukee: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 29, 30% April 25, 40% April 22, 50% April 19, 60% April 16, 70% April 13, 80% April 9, 90% April 6. Observed last spring frost in recent years: 2021 April 22, 2022 April 27, 2023 April 17, 2024 April 25, 2025 April 12, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 2Apr 19Apr 62021: April 222022: April 272023: April 172024: April 252025: April 122026: April 20Fall near Milwaukee: chance of a frost before this dateFall, chance of a frost before the date: 10% October 15, 20% October 20, 30% October 24, 40% October 26, 50% October 29, 60% November 1, 70% November 2, 80% November 6, 90% November 10. Observed first fall frost in recent years: 2021 November 2, 2022 November 13, 2023 October 30, 2024 November 20, 2025 October 25.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 15Oct 29Nov 102021: November 22022: November 132023: October 302024: November 202025: October 25
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
2021April 22November 2
2022April 27November 13
2023April 17October 30
2024April 25November 20
2025April 12October 25
2026April 20season not over yet

What these dates mean

October 15 marks the cautious fall date in the Milwaukee area for finishing the harvest, carrying only a 10 % chance that a light frost has arrived earlier.

The 50% date for light frost in spring is April 19, meaning a gardener faces a 50 % chance of frost later than that day; the 50% date in fall is October 29, with a 50 % chance of frost earlier than it. For tender crops the cautious spring date is May 2, when the chance of a later frost drops to 10 %; the cautious fall date, already noted, is October 15. By contrast, planting on April 6 in spring or counting on crops through November 10 in fall carries a 90 % chance of encountering a light frost, a gamble.

Hard frosts, recorded at 28 °F, are more damaging than light frosts at 32 °F, and the median hard-frost dates are April 6 in spring and November 8 in fall.

How to read the probabilities

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

  • Spring: "10% after May 2" 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 October 15" 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 Milwaukee, WINumbered nearest stations: 1 — near Wauwatosa, WI — 10 mi; 2 — Racine, WI — 18 mi; 3 — Germantown, WI — 22 mi; 4 — Burlington, WI — 28 mi; 5 — Kenosha, WI — 28 mi.WIILMI25 mi · 40 km1. near Wauwatosa, WI — 10 mi12. Racine, WI — 18 mi23. Germantown, WI — 22 mi34. Burlington, WI — 28 mi45. Kenosha, WI — 28 mi5
  1. near Wauwatosa, WI 10 mi (17 km)
  2. Racine, WI 18 mi (30 km)
  3. Germantown, WI 22 mi (36 km)
  4. Burlington, WI 28 mi (44 km)
  5. Kenosha, WI 28 mi (44 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 42.955, -87.9044.