U.S. Frost Dates by Weather Station

NOAA station USC00112931 · Illinois

Frost Dates near Fairfield, IL

NOAA weather station Fairfield Radio Wfiw (USC00112931), Illinois · elevation 430 ft (131 m) · hardiness zone 6b*

Fairfield is the nearest town to the station (1.8 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 23only 1 spring in 10 still has a frost later
  • Typical last frostApril 750% chance of a frost after it
  • Typical first fall frostOctober 2650% chance of a frost before it
  • Frost-free season201 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season near Fairfield, ILSpring: a frost after March 23 in 9 years out of 10, after April 7 in half of the years, after April 23 in 1 year out of 10. Fall: the first frost comes before October 14 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 201 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 7First frost ~Oct 26Frost season near Fairfield, ILSpring: a frost after March 23 in 9 years out of 10, after April 7 in half of the years, after April 23 in 1 year out of 10. Fall: the first frost comes before October 14 in 1 year out of 10, before October 26 in half of the years, before November 9 in 9 years out of 10. Typical frost-free season: 201 days.JFMAMJJASONDLast frost ~Apr 7First frost ~Oct 26
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)April 23October 14
50% (typical)April 7October 26
90% (likely)March 23November 9
Frost-free season (32°F, 50% chance)
201 days
Hard frost (28°F), last in spring, 50% chance after
March 27
Hard frost (28°F), first in fall, 50% chance before
November 6

The last 15 years (2006–2020 normals)

Typical last frost April 8 (1 day later than the 30-year normal), typical first fall frost October 29 (3 days later). Frost-free season 203 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 near Fairfield: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 23, 20% April 18, 30% April 13, 40% April 10, 50% April 7, 60% April 3, 70% April 1, 80% March 29, 90% March 23. Observed last spring frost in recent years: 2021 April 22, 2022 April 3, 2024 April 7, 2025 April 9, 2026 March 29.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 23Apr 7Mar 232021: April 222022: April 32024: April 72025: April 92026: March 29Fall near Fairfield: chance of a frost before this dateFall, chance of a frost before the date: 10% October 14, 20% October 19, 30% October 22, 40% October 24, 50% October 26, 60% October 29, 70% October 31, 80% November 4, 90% November 9. Observed first fall frost in recent years: 2021 November 3, 2022 October 18, 2024 November 26, 2025 November 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Dec 1Oct 14Oct 26Nov 92021: November 32022: October 182024: November 262025: November 10
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 3
2022April 3October 18
2023incomplete recordincomplete record
2024April 7November 26
2025April 9November 10
2026March 29season not over yet

What these dates mean

In the Fairfield area, planting tender crops on March 23 carries a 90% chance that a light frost will still occur later that spring.

The 50% dates—April 7 for spring and October 26 for fall—mark the point at which a light frost is just as likely to have passed as to still arrive, giving gardeners an even-odds reference. A cautious schedule would wait until April 23 to set out tender crops in spring and finish harvesting them by October 14 in fall, when the chance of a later (or earlier) frost drops to 10%.

The median hard-frost dates are March 27 and November 6; a hard frost at 28°F can injure or kill plants that would otherwise tolerate 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 23" 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 14" 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 Fairfield, ILNumbered nearest stations: 1 — Carmi, IL — 23 mi; 2 — Olney, IL — 26 mi; 3 — Mount Vernon, IL — 29 mi; 4 — Salem, IL — 38 mi; 5 — Mount Vernon, IN — 39 mi.INKY25 mi · 40 km1. Carmi, IL — 23 mi12. Olney, IL — 26 mi23. Mount Vernon, IL — 29 mi34. Salem, IL — 38 mi45. Mount Vernon, IN — 39 mi5
  1. Carmi, IL 23 mi (36 km)
  2. Olney, IL 26 mi (41 km)
  3. Mount Vernon, IL 29 mi (46 km)
  4. Salem, IL 38 mi (61 km)
  5. Mount Vernon, IN 39 mi (63 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: 38.3806, -88.3264.