U.S. Frost Dates by Weather Station

NOAA station USW00093989 · Illinois

Frost Dates for Quincy, IL

NOAA weather station Quincy Regional Airport (USW00093989), Illinois · elevation 769 ft (234 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 1only 1 spring in 10 still has a frost later
  • Typical last frostApril 1450% chance of a frost after it
  • Typical first fall frostOctober 2350% chance of a frost before it
  • Frost-free season191 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Quincy, ILSpring: a frost after March 30 in 9 years out of 10, after April 14 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 23 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 191 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 14First frost ~Oct 23Frost season at Quincy, ILSpring: a frost after March 30 in 9 years out of 10, after April 14 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 10 in 1 year out of 10, before October 23 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 191 days.JFMAMJJASONDLast frost ~Apr 14First frost ~Oct 23
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 10
50% (typical)April 14October 23
90% (likely)March 30November 4
Frost-free season (32°F, 50% chance)
191 days
Hard frost (28°F), last in spring, 50% chance after
April 4
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 15 (1 day later than the 30-year normal), typical first fall frost October 24 (1 day later). Frost-free season 190 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 Quincy: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 1, 20% April 25, 30% April 21, 40% April 18, 50% April 14, 60% April 11, 70% April 8, 80% April 4, 90% March 30. Observed last spring frost in recent years: 2021 April 22, 2022 April 26, 2023 April 6, 2024 April 5, 2025 April 8, 2026 March 28.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 1Apr 14Mar 302021: April 222022: April 262023: April 62024: April 52025: April 82026: March 28Fall at Quincy: chance of a frost before this dateFall, chance of a frost before the date: 10% October 10, 20% October 15, 30% October 17, 40% October 20, 50% October 23, 60% October 25, 70% October 28, 80% October 31, 90% November 4. Observed first fall frost in recent years: 2021 November 2, 2022 October 8, 2023 October 30, 2024 October 16, 2025 November 1.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 10Oct 23Nov 42021: November 22022: October 82023: October 302024: October 162025: November 1
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 2
2022April 26October 8
2023April 6October 30
2024April 5October 16
2025April 8November 1
2026March 28season not over yet

What these dates mean

The 191 days between the 32°F 50% dates in Quincy bracket the interval when a gardener can normally work without a light frost. The 50% date in spring is April 14, indicating a 50% chance of a light frost later than this date, and the 50% date in fall is October 23, indicating a 50% chance of a light frost earlier than this date. For a cautious plan, the spring cautious date is May 1, when only a 10% chance of a later frost remains, while the fall cautious date is October 10, when there is only a 10% chance a frost has already arrived.

The 50% hard-frost dates are April 4 in spring and November 1 in fall; a hard frost at 28°F can damage plant tissue more severely than 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 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 10" 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 Quincy, ILNumbered nearest stations: 1 — Quincy Dam 21, IL — 13 mi; 2 — Hannibal, MO — 18 mi; 3 — Saverton Lock and Dam 22, MO — 21 mi; 4 — near Canton, MO — 22 mi; 5 — Bentley, IL — 28 mi.ILMOIA25 mi · 40 km1. Quincy Dam 21, IL — 13 mi12. Hannibal, MO — 18 mi23. Saverton Lock and Dam 22, MO — 21 mi34. near Canton, MO — 22 mi45. Bentley, IL — 28 mi5
  1. Quincy Dam 21, IL 13 mi (20 km)
  2. Hannibal, MO 18 mi (28 km)
  3. Saverton Lock and Dam 22, MO 21 mi (34 km)
  4. near Canton, MO 22 mi (36 km)
  5. Bentley, IL 28 mi (46 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: 39.9369, -91.1919.