U.S. Frost Dates by Weather Station

NOAA station USC00111302 · Illinois

Frost Dates for Carmi, IL

NOAA weather station Carmi 3 (USC00111302), Illinois · elevation 335 ft (102 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1550% chance of a frost after it
  • Typical first fall frostOctober 1950% chance of a frost before it
  • Frost-free season183 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Carmi, ILSpring: a frost after April 2 in 9 years out of 10, after April 15 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 19 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 183 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 15First frost ~Oct 19Frost season at Carmi, ILSpring: a frost after April 2 in 9 years out of 10, after April 15 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 19 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 183 days.JFMAMJJASONDLast frost ~Apr 15First frost ~Oct 19
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 2October 4
50% (typical)April 15October 19
90% (likely)April 2October 29
Frost-free season (32°F, 50% chance)
183 days
Hard frost (28°F), last in spring, 50% chance after
April 3
Hard frost (28°F), first in fall, 50% chance before
October 28

The last 15 years (2006–2020 normals)

Typical last frost April 15 (same as the 30-year normal), typical first fall frost October 21 (2 days later). Frost-free season 188 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 Carmi: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 27, 30% April 23, 40% April 19, 50% April 15, 60% April 13, 70% April 10, 80% April 7, 90% April 2. Observed last spring frost in recent years: 2021 May 11, 2022 April 19, 2023 April 24.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 2Apr 15Apr 22021: May 112022: April 192023: April 24Fall at Carmi: chance of a frost before this dateFall, chance of a frost before the date: 10% October 4, 20% October 8, 30% October 12, 40% October 16, 50% October 19, 60% October 20, 70% October 23, 80% October 26, 90% October 29. Observed first fall frost in recent years: 2021 November 2, 2022 October 9, 2023 October 31.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 4Oct 19Oct 292021: November 22022: October 92023: October 31
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 11November 2
2022April 19October 9
2023April 24October 31
2024incomplete recordincomplete record
2025incomplete recordno data
2026no dataseason not over yet

What these dates mean

October 4 marks the cautious fall date for finishing the harvest of tender crops in Carmi, because there is only a 10 % chance that a light frost has arrived earlier.

In spring the cautious date for setting out tender crops is May 2, when the chance of a later light frost is just 10 %; planting on April 2 carries a 90 % gamble. The median light-frost dates are April 15 and October 19; these 50 % dates indicate the point at which a gardener faces an even chance of a frost occurring later (spring) or earlier (fall).

The hard-frost 50 % dates are April 3 in spring and October 28 in fall, and a hard frost at 28 °F can damage plants that survive a 32 °F light frost, making it a more serious threat.

How to read the probabilities

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

  • Spring: "10% after May 2" 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 4" 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 Carmi, ILNumbered nearest stations: 1 — Mount Vernon, IN — 18 mi; 2 — near Fairfield, IL — 23 mi; 3 — Evansville, IN — 36 mi; 4 — Henderson, KY — 36 mi; 5 — Princeton, IN — 38 mi.ILINKY25 mi · 40 km1. Mount Vernon, IN — 18 mi12. near Fairfield, IL — 23 mi23. Evansville, IN — 36 mi34. Henderson, KY — 36 mi45. Princeton, IN — 38 mi5
  1. Mount Vernon, IN 18 mi (30 km)
  2. near Fairfield, IL 23 mi (36 km)
  3. Evansville, IN 36 mi (58 km)
  4. Henderson, KY 36 mi (59 km)
  5. Princeton, IN 38 mi (60 km)

Sources

* Hardiness zone 6b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 38.0733, -88.1805.