U.S. Frost Dates by Weather Station

NOAA station USC00475932 · Wisconsin

Frost Dates for New London, WI

NOAA weather station New London (USC00475932), Wisconsin · elevation 800 ft (244 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 19only 1 spring in 10 still has a frost later
  • Typical last frostMay 450% chance of a frost after it
  • Typical first fall frostOctober 650% chance of a frost before it
  • Frost-free season153 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at New London, WISpring: a frost after April 21 in 9 years out of 10, after May 4 in half of the years, after May 19 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 6 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 153 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 4First frost ~Oct 6Frost season at New London, WISpring: a frost after April 21 in 9 years out of 10, after May 4 in half of the years, after May 19 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 6 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 153 days.JFMAMJJASONDLast frost ~May 4First frost ~Oct 6
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 19September 22
50% (typical)May 4October 6
90% (likely)April 21October 22
Frost-free season (32°F, 50% chance)
153 days
Hard frost (28°F), last in spring, 50% chance after
April 24
Hard frost (28°F), first in fall, 50% chance before
October 18

The last 15 years (2006–2020 normals)

Typical last frost May 6 (2 days later than the 30-year normal), typical first fall frost October 7 (1 day 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 New London: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 19, 20% May 14, 30% May 10, 40% May 7, 50% May 4, 60% May 2, 70% April 30, 80% April 26, 90% April 21. Observed last spring frost in recent years: 2021 May 11, 2022 April 29, 2023 May 4, 2024 April 26.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 19May 4Apr 212021: May 112022: April 292023: May 42024: April 26Fall at New London: chance of a frost before this dateFall, chance of a frost before the date: 10% September 22, 20% September 27, 30% October 1, 40% October 2, 50% October 6, 60% October 8, 70% October 12, 80% October 16, 90% October 22. Observed first fall frost in recent years: 2021 October 22, 2022 October 15, 2023 October 22, 2024 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 22Oct 6Oct 222021: October 222022: October 152023: October 222024: October 24
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 22
2022April 29October 15
2023May 4October 22
2024April 26October 24
2025no datano data
2026no dataseason not over yet

What these dates mean

Setting out tender crops on the early spring date, April 21, is a gamble: there is a 90 % chance of a light frost occurring later that season in New London. The cautious approach waits until May 19, when only a 10 % chance of a later frost remains.

The 50 % light-frost dates are May 4 in spring and October 6 in fall, each representing an even-odds chance of a light frost. The 50 % hard-frost dates are April 24 in spring and October 18 in fall, each indicating a 50 % chance of a hard frost. For a careful schedule, gardeners finish tender-crop harvest by September 22, the fall cautious date with a 10 % chance that a frost has already arrived.

A hard frost at 28 °F poses a greater threat to plant tissue 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 19" 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 New London, WINumbered nearest stations: 1 — Waupaca, WI — 17 mi; 2 — Clintonville, WI — 18 mi; 3 — Oshkosh, WI — 25 mi; 4 — Shawano, WI — 28 mi; 5 — Green Bay, WI — 32 mi.25 mi · 40 km1. Waupaca, WI — 17 mi12. Clintonville, WI — 18 mi23. Oshkosh, WI — 25 mi34. Shawano, WI — 28 mi45. Green Bay, WI — 32 mi5
  1. Waupaca, WI 17 mi (27 km)
  2. Clintonville, WI 18 mi (29 km)
  3. Oshkosh, WI 25 mi (40 km)
  4. Shawano, WI 28 mi (46 km)
  5. Green Bay, WI 32 mi (51 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: 44.3586, -88.7189.