U.S. Frost Dates by Weather Station

NOAA station USC00117126 · Illinois

Frost Dates for Ramsey, IL

NOAA weather station Ramsey (USC00117126), Illinois · elevation 600 ft (183 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 1only 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 season185 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Ramsey, ILSpring: a frost after April 3 in 9 years out of 10, after April 15 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 3 in 1 year out of 10, before October 19 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 185 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 15First frost ~Oct 19Frost season at Ramsey, ILSpring: a frost after April 3 in 9 years out of 10, after April 15 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 3 in 1 year out of 10, before October 19 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 185 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 1October 3
50% (typical)April 15October 19
90% (likely)April 3October 31
Frost-free season (32°F, 50% chance)
185 days
Hard frost (28°F), last in spring, 50% chance after
April 4
Hard frost (28°F), first in fall, 50% chance before
October 30

The last 15 years (2006–2020 normals)

Typical last frost April 14 (1 day earlier than the 30-year normal), typical first fall frost October 22 (3 days 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 Ramsey: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 1, 20% April 26, 30% April 21, 40% April 18, 50% April 15, 60% April 12, 70% April 10, 80% April 7, 90% April 3. Observed last spring frost in recent years: 2021 April 23, 2022 April 19.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 1Apr 15Apr 32021: April 232022: April 19Fall at Ramsey: chance of a frost before this dateFall, chance of a frost before the date: 10% October 3, 20% October 10, 30% October 14, 40% October 17, 50% October 19, 60% October 22, 70% October 24, 80% October 27, 90% October 31. Observed first fall frost in recent years: 2021 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 3Oct 19Oct 312021: November 3
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 23November 3
2022April 19incomplete record
2023incomplete recordno data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

May 1 is the cautious spring date, giving a gardener a ten-percent chance that a light frost will occur later and therefore a reasonable window to set out tender crops. By contrast, April 3 carries a ninety-percent chance of a frost later, making an earlier planting a gamble.

The 50% dates are April 15 for spring and October 19 for fall; each marks the point where a light frost is as likely as not, so a gardener can expect roughly even odds of frost on either side of those days. The median hard-frost dates are April 4 and October 30, and a hard frost at 28 °F is more damaging than a light frost at 32 °F because it can injure plants that survive the milder temperature.

October 3 is the cautious fall date, with only a ten-percent chance that a light frost has already arrived, allowing a gardener to finish harvesting tender crops with relatively low risk.

How to read the probabilities

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

  • Spring: "10% after May 1" 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 3" 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 Ramsey, ILNumbered nearest stations: 1 — Hillsboro, IL — 21 mi; 2 — Effingham, IL — 26 mi; 3 — Windsor, IL — 34 mi; 4 — Salem, IL — 36 mi; 5 — near Carlyle, IL — 39 mi.INMO25 mi · 40 km1. Hillsboro, IL — 21 mi12. Effingham, IL — 26 mi23. Windsor, IL — 34 mi34. Salem, IL — 36 mi45. near Carlyle, IL — 39 mi5
  1. Hillsboro, IL 21 mi (34 km)
  2. Effingham, IL 26 mi (41 km)
  3. Windsor, IL 34 mi (55 km)
  4. Salem, IL 36 mi (58 km)
  5. near Carlyle, IL 39 mi (62 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: 39.1481, -89.1022.