U.S. Frost Dates by Weather Station

NOAA station USC00113455 · Illinois

Frost Dates near Oquawka, IL

NOAA weather station Gladstone Dam 18 (USC00113455), Illinois · elevation 538 ft (164 m) · hardiness zone 6a*

Oquawka is the nearest town to the station (5.3 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 850% chance of a frost after it
  • Typical first fall frostOctober 2950% chance of a frost before it
  • Frost-free season202 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Oquawka, ILSpring: a frost after March 26 in 9 years out of 10, after April 8 in half of the years, after April 23 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 29 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 202 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 8First frost ~Oct 29Frost season near Oquawka, ILSpring: a frost after March 26 in 9 years out of 10, after April 8 in half of the years, after April 23 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 29 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 202 days.JFMAMJJASONDLast frost ~Apr 8First frost ~Oct 29
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.Today

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)April 23October 17
50% (typical)April 8October 29
90% (likely)March 26November 10
Frost-free season (32°F, 50% chance)
202 days
Hard frost (28°F), last in spring, 50% chance after
March 31
Hard frost (28°F), first in fall, 50% chance before
November 7

The last 15 years (2006–2020 normals)

Typical last frost April 9 (1 day later than the 30-year normal), typical first fall frost October 30 (1 day 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 Oquawka: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 23, 20% April 18, 30% April 14, 40% April 11, 50% April 8, 60% April 6, 70% April 3, 80% April 1, 90% March 26. Observed last spring frost in recent years: 2021 April 22, 2022 April 27, 2023 April 7, 2024 April 3, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 23Apr 8Mar 262021: April 222022: April 272023: April 72024: April 32025: April 92026: April 21Fall near Oquawka: chance of a frost before this dateFall, chance of a frost before the date: 10% October 17, 20% October 21, 30% October 25, 40% October 27, 50% October 29, 60% October 31, 70% November 2, 80% November 5, 90% November 10. Observed first fall frost in recent years: 2021 November 3, 2022 October 14, 2023 October 30, 2024 October 17, 2025 November 2.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 17Oct 29Nov 102021: November 32022: October 142023: 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 3
2022April 27October 14
2023April 7October 30
2024April 3October 17
2025April 9November 2
2026April 21season not over yet

What these dates mean

In the Oquawka area, the cautious fall date to finish harvesting tender crops is October 17, when there is only a 10 % chance a light frost has arrived.

For spring planting, the cautious date for setting out tender crops is April 23, which carries a 10 % chance of a light frost later than that day; the 50% date is April 8, meaning there is an even chance of a frost after it. In fall, the 50% date is October 29, indicating an even chance of a frost before it. The median hard-frost dates are March 31 in spring and November 7 in fall. The two 32°F 50% dates are 202 days apart, marking the interval between even-odds light-frost risk in spring and fall.

A hard frost at 28 °F can damage plants that would survive 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 17" 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 Oquawka, ILNumbered nearest stations: 1 — Burlington (Airport), IA — 9 mi; 2 — near Burlington, IA — 9 mi; 3 — Monmouth, IL — 21 mi; 4 — Fort Madison, IA — 24 mi; 5 — Aledo, IL — 26 mi.ILIAMO25 mi · 40 km1. Burlington (Airport), IA — 9 mi12. near Burlington, IA — 9 mi23. Monmouth, IL — 21 mi34. Fort Madison, IA — 24 mi45. Aledo, IL — 26 mi5
  1. Burlington (Airport), IA 9 mi (14 km)
  2. near Burlington, IA 9 mi (14 km)
  3. Monmouth, IL 21 mi (33 km)
  4. Fort Madison, IA 24 mi (39 km)
  5. Aledo, IL 26 mi (42 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: 40.8822, -91.0233.