U.S. Frost Dates by Weather Station

NOAA station USC00112140 · Illinois

Frost Dates for Danville, IL

NOAA weather station Danville (USC00112140), Illinois · elevation 555 ft (169 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 7only 1 spring in 10 still has a frost later
  • Typical last frostApril 2150% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season181 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Danville, ILSpring: a frost after April 6 in 9 years out of 10, after April 21 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 20 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 181 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 21First frost ~Oct 20Frost season at Danville, ILSpring: a frost after April 6 in 9 years out of 10, after April 21 in half of the years, after May 7 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 20 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 181 days.JFMAMJJASONDLast frost ~Apr 21First frost ~Oct 20
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 7October 6
50% (typical)April 21October 20
90% (likely)April 6November 1
Frost-free season (32°F, 50% chance)
181 days
Hard frost (28°F), last in spring, 50% chance after
April 8
Hard frost (28°F), first in fall, 50% chance before
October 31

The last 15 years (2006–2020 normals)

Typical last frost April 21 (same as the 30-year normal), typical first fall frost October 22 (2 days later). Frost-free season 182 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 Danville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 7, 20% May 1, 30% April 27, 40% April 24, 50% April 21, 60% April 18, 70% April 14, 80% April 11, 90% April 6. Observed last spring frost in recent years: 2021 May 12, 2023 April 27, 2024 April 25, 2025 April 12, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 7Apr 21Apr 62021: May 122023: April 272024: April 252025: April 122026: April 20Fall at Danville: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 11, 30% October 15, 40% October 18, 50% October 20, 60% October 23, 70% October 25, 80% October 29, 90% November 1. Observed first fall frost in recent years: 2021 November 1, 2022 October 8, 2023 October 30, 2024 October 16, 2025 October 23.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 20Nov 12021: November 12022: October 82023: October 302024: October 162025: October 23
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 12November 1
2022incomplete recordOctober 8
2023April 27October 30
2024April 25October 16
2025April 12October 23
2026April 20season not over yet

What these dates mean

The 181 days between the 50% dates in Danville define the period when light frosts are equally likely to have occurred or not. The 32°F 50% spring date is April 21 and the 32°F 50% fall date is October 20; a gardener can expect a 50% chance of a light frost later than April 21 in spring and a 50% chance of a light frost earlier than October 20 in fall. The hard-frost 28°F 50% dates are April 8 and October 31.

For a cautious plan, tender crops are best set out after the May 7 light-frost date, which carries a 10% chance of frost later, while harvesting should be completed by the October 6 light-frost date, which carries a 10% chance of frost earlier. Planting on April 6 or keeping crops to November 1 would involve a 90% chance of frost and is therefore a gamble. Hard frost matters more than light frost because temperatures of 28°F can kill plant tissue that can survive the milder 32°F light frost.

How to read the probabilities

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

  • Spring: "10% after May 7" 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 6" 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 Danville, ILNumbered nearest stations: 1 — Perrysville, IN — 9 mi; 2 — Hoopeston, IL — 23 mi; 3 — Rantoul, IL — 30 mi; 4 — Champaign, IL — 32 mi; 5 — near Paris, IL — 36 mi.ILIN25 mi · 40 km1. Perrysville, IN — 9 mi12. Hoopeston, IL — 23 mi23. Rantoul, IL — 30 mi34. Champaign, IL — 32 mi45. near Paris, IL — 36 mi5
  1. Perrysville, IN 9 mi (14 km)
  2. Hoopeston, IL 23 mi (37 km)
  3. Rantoul, IL 30 mi (48 km)
  4. Champaign, IL 32 mi (51 km)
  5. near Paris, IL 36 mi (58 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: 40.1392, -87.6478.