U.S. Frost Dates by Weather Station

NOAA station USC00475335 · Wisconsin

Frost Dates for Menomonie, WI

NOAA weather station Menomonie (USC00475335), Wisconsin · elevation 780 ft (238 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 24only 1 spring in 10 still has a frost later
  • Typical last frostMay 950% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season143 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Menomonie, WISpring: a frost after April 27 in 9 years out of 10, after May 9 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 143 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 9First frost ~Oct 1Frost season at Menomonie, WISpring: a frost after April 27 in 9 years out of 10, after May 9 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 143 days.JFMAMJJASONDLast frost ~May 9First frost ~Oct 1
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.Today

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)May 24September 19
50% (typical)May 9October 1
90% (likely)April 27October 14
Frost-free season (32°F, 50% chance)
143 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 10

The last 15 years (2006–2020 normals)

Typical last frost May 6 (3 days earlier than the 30-year normal), typical first fall frost October 8 (7 days later). Frost-free season 152 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 Menomonie: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 24, 20% May 19, 30% May 16, 40% May 13, 50% May 9, 60% May 7, 70% May 4, 80% May 1, 90% April 27. Observed last spring frost in recent years: 2021 May 12, 2022 May 5, 2023 May 4, 2024 April 26, 2025 May 1, 2026 May 12.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 24May 9Apr 272021: May 122022: May 52023: May 42024: April 262025: May 12026: May 12Fall at Menomonie: chance of a frost before this dateFall, chance of a frost before the date: 10% September 19, 20% September 23, 30% September 26, 40% September 29, 50% October 1, 60% October 4, 70% October 6, 80% October 9, 90% October 14. Observed first fall frost in recent years: 2021 October 22, 2022 September 29, 2023 October 19, 2024 October 15, 2025 October 8.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 19Oct 1Oct 142021: October 222022: September 292023: October 192024: October 152025: October 8
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 22
2022May 5September 29
2023May 4October 19
2024April 26October 15
2025May 1October 8
2026May 12season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Menomonie is September 19, when there is only a 10 % chance that a light frost has arrived.

In spring, the 50 % date is May 9, marking an even odds point for a light frost occurring later, while the 50 % date in fall is October 1, marking an even odds point for a light frost occurring earlier. A gardener who wants to reduce risk would wait until the cautious spring date of May 24 before setting out tender crops, and would aim to complete tender-crop harvest by the cautious fall date of September 19.

Hard frost, defined at 28 °F, can damage plants more severely than a light frost at 32 °F, so the median hard-frost dates of April 30 and October 10 are important reference points.

How to read the probabilities

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

  • Spring: "10% after May 24" 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 19" 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 Menomonie, WINumbered nearest stations: 1 — Eau Claire, WI — 22 mi; 2 — Ridgeland, WI — 24 mi; 3 — Mondovi, WI — 25 mi; 4 — Bloomer, WI — 27 mi; 5 — Ellsworth, WI — 27 mi.MN25 mi · 40 km1. Eau Claire, WI — 22 mi12. Ridgeland, WI — 24 mi23. Mondovi, WI — 25 mi34. Bloomer, WI — 27 mi45. Ellsworth, WI — 27 mi5
  1. Eau Claire, WI 22 mi (35 km)
  2. Ridgeland, WI 24 mi (38 km)
  3. Mondovi, WI 25 mi (40 km)
  4. Bloomer, WI 27 mi (43 km)
  5. Ellsworth, WI 27 mi (44 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: 44.8742, -91.9364.