U.S. Frost Dates by Weather Station

NOAA station USC00118740 · Illinois

Frost Dates for Champaign, IL

NOAA weather station Champaign 3 S (USC00118740), Illinois · elevation 721 ft (220 m) · hardiness zone 6a*

  • Lower-risk planting dateafter April 29only 1 spring in 10 still has a frost later
  • Typical last frostApril 1550% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season190 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Champaign, ILSpring: a frost after April 1 in 9 years out of 10, after April 15 in half of the years, after April 29 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 24 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 190 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 15First frost ~Oct 24Frost season at Champaign, ILSpring: a frost after April 1 in 9 years out of 10, after April 15 in half of the years, after April 29 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 24 in half of the years, before November 5 in 9 years out of 10. Typical frost-free season: 190 days.JFMAMJJASONDLast frost ~Apr 15First frost ~Oct 24
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)April 29October 11
50% (typical)April 15October 24
90% (likely)April 1November 5
Frost-free season (32°F, 50% chance)
190 days
Hard frost (28°F), last in spring, 50% chance after
April 4
Hard frost (28°F), first in fall, 50% chance before
November 2

The last 15 years (2006–2020 normals)

Typical last frost April 16 (1 day later than the 30-year normal), typical first fall frost October 25 (1 day later). Frost-free season 189 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 Champaign: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 29, 20% April 24, 30% April 21, 40% April 18, 50% April 15, 60% April 12, 70% April 8, 80% April 5, 90% April 1. Observed last spring frost in recent years: 2021 April 22, 2022 April 19, 2023 April 24, 2024 April 25, 2025 April 12, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 29Apr 15Apr 12021: April 222022: April 192023: April 242024: April 252025: April 122026: April 20Fall at Champaign: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 16, 30% October 19, 40% October 22, 50% October 24, 60% October 26, 70% October 29, 80% October 31, 90% November 5. Observed first fall frost in recent years: 2021 November 1, 2022 October 18, 2023 October 30, 2024 October 17, 2025 November 2.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 24Nov 52021: November 12022: October 182023: October 302024: October 172025: November 2
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 1
2022April 19October 18
2023April 24October 30
2024April 25October 17
2025April 12November 2
2026April 20season not over yet

What these dates mean

October 11 is the cautious fall date for finishing the harvest of tender crops in Champaign, as it carries only a 10% chance that a light frost has already arrived.

In spring, the cautious date for setting out tender crops is April 29, which has a 10% chance of a frost later than that day, while the 50% date is April 15, indicating an even-odds point for a light frost. For the autumn season the 50% date is October 24, marking the median moment when a light frost is equally likely to have occurred earlier.

The hard-frost 50% dates are April 4 in spring and November 2 in fall; a hard frost at 28°F can injure plants more severely 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 April 29" 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 11" 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 Champaign, ILNumbered nearest stations: 1 — Rantoul, IL — 16 mi; 2 — Tuscola, IL — 20 mi; 3 — Danville, IL — 32 mi; 4 — Perrysville, IN — 39 mi; 5 — Hoopeston, IL — 39 mi.ILIN25 mi · 40 km1. Rantoul, IL — 16 mi12. Tuscola, IL — 20 mi23. Danville, IL — 32 mi34. Perrysville, IN — 39 mi45. Hoopeston, IL — 39 mi5
  1. Rantoul, IL 16 mi (26 km)
  2. Tuscola, IL 20 mi (32 km)
  3. Danville, IL 32 mi (51 km)
  4. Perrysville, IN 39 mi (62 km)
  5. Hoopeston, IL 39 mi (63 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: 40.0839, -88.2403.