U.S. Frost Dates by Weather Station

NOAA station USC00472173 · Wisconsin

Frost Dates for Dodgeville, WI

NOAA weather station Dodgeville WWTP (USC00472173), Wisconsin · elevation 1118 ft (341 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 17only 1 spring in 10 still has a frost later
  • Typical last frostMay 350% chance of a frost after it
  • Typical first fall frostOctober 750% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Dodgeville, WISpring: a frost after April 19 in 9 years out of 10, after May 3 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 7 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 3First frost ~Oct 7Frost season at Dodgeville, WISpring: a frost after April 19 in 9 years out of 10, after May 3 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 7 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~May 3First frost ~Oct 7
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 17September 25
50% (typical)May 3October 7
90% (likely)April 19October 20
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 18

The last 15 years (2006–2020 normals)

Typical last frost May 3 (same as the 30-year normal), typical first fall frost October 12 (5 days later). Frost-free season 162 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 Dodgeville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 17, 20% May 12, 30% May 9, 40% May 5, 50% May 3, 60% April 30, 70% April 27, 80% April 24, 90% April 19. Observed last spring frost in recent years: 2021 May 12, 2022 May 4, 2023 April 27, 2024 April 25, 2025 May 9, 2026 May 8.Spring: last frostChance of a frost after this date10%50%90%May 1May 17May 3Apr 192021: May 122022: May 42023: April 272024: April 252025: May 92026: May 8Fall at Dodgeville: chance of a frost before this dateFall, chance of a frost before the date: 10% September 25, 20% September 30, 30% October 2, 40% October 5, 50% October 7, 60% October 10, 70% October 13, 80% October 16, 90% October 20. Observed first fall frost in recent years: 2021 October 23, 2022 September 29, 2023 October 11, 2024 October 16, 2025 October 20.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 25Oct 7Oct 202021: October 232022: September 292023: October 112024: October 162025: October 20
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 23
2022May 4September 29
2023April 27October 11
2024April 25October 16
2025May 9October 20
2026May 8season not over yet

What these dates mean

May 17 is the cautious spring light-frost date for Dodgeville; with only a 10 % chance of a frost later, a gardener can plan to set out tender crops after this day.

The 50% light-frost dates are May 3 in spring and October 7 in fall, meaning there is an even chance of a frost occurring later (spring) or earlier (fall) than each date. For a conservative schedule, the cautious fall light-frost date is September 25, when there is only a 10 % chance that a frost has arrived earlier. The hard-frost 50% dates are April 22 and October 18; a hard frost at 28 °F can damage plants that survive a 32 °F light frost. The record covers 25 years and the interval between the two 32 °F 50% dates is 157 days.

How to read the probabilities

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

  • Spring: "10% after May 17" 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 25" 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 Dodgeville, WINumbered nearest stations: 1 — Charmany Farm, WI — 33 mi; 2 — UW Arboretum - Madison, WI — 35 mi; 3 — Lancaster, WI — 35 mi; 4 — Stockton, IL — 39 mi; 5 — Dubuque Lock and Dam 11, IA — 40 mi.ILIA25 mi · 40 km1. Charmany Farm, WI — 33 mi12. UW Arboretum - Madison, WI — 35 mi23. Lancaster, WI — 35 mi34. Stockton, IL — 39 mi45. Dubuque Lock and Dam 11, IA — 40 mi5
  1. Charmany Farm, WI 33 mi (53 km)
  2. UW Arboretum - Madison, WI 35 mi (57 km)
  3. Lancaster, WI 35 mi (57 km)
  4. Stockton, IL 39 mi (63 km)
  5. Dubuque Lock and Dam 11, IA 40 mi (64 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: 42.9608, -90.1161.