U.S. Frost Dates by Weather Station

NOAA station USC00116661 · Illinois

Frost Dates for Paw Paw, IL

NOAA weather station Paw Paw 2 S (USC00116661), Illinois · elevation 889 ft (271 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 12only 1 spring in 10 still has a frost later
  • Typical last frostApril 2750% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season171 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Paw Paw, ILSpring: a frost after April 12 in 9 years out of 10, after April 27 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 15 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 171 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 27First frost ~Oct 15Frost season at Paw Paw, ILSpring: a frost after April 12 in 9 years out of 10, after April 27 in half of the years, after May 12 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 15 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 171 days.JFMAMJJASONDLast frost ~Apr 27First frost ~Oct 15
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 12September 30
50% (typical)April 27October 15
90% (likely)April 12October 26
Frost-free season (32°F, 50% chance)
171 days
Hard frost (28°F), last in spring, 50% chance after
April 15
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost April 27 (same as the 30-year normal), typical first fall frost October 17 (2 days later). Frost-free season 171 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 Paw Paw: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 12, 20% May 6, 30% May 3, 40% April 30, 50% April 27, 60% April 24, 70% April 21, 80% April 18, 90% April 12. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 May 4, 2024 April 25, 2025 April 16, 2026 May 7.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 12Apr 27Apr 122021: May 112022: April 282023: May 42024: April 252025: April 162026: May 7Fall at Paw Paw: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 6, 30% October 9, 40% October 12, 50% October 15, 60% October 18, 70% October 20, 80% October 23, 90% October 26. Observed first fall frost in recent years: 2021 October 23, 2022 October 8, 2023 October 30, 2024 October 16, 2025 October 23.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 15Oct 262021: October 232022: October 82023: October 302024: October 162025: October 23
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 11October 23
2022April 28October 8
2023May 4October 30
2024April 25October 16
2025April 16October 23
2026May 7season not over yet

What these dates mean

May 12 is the cautious spring light-frost date in Paw Paw, carrying only a 10 % chance of a later frost and therefore marking the point when a gardener can plan to set out tender crops with confidence. The median light-frost dates are April 27 in spring and October 15 in fall; each represents an even-odds moment that is not itself a frost date but indicates when the likelihood of frost switches from more likely to less likely. For a careful fall schedule, September 30 serves as the cautious date, offering only a 10 % chance that a frost has arrived earlier and signaling when tender crops should be finished harvesting. Hard frost at 28 °F is more damaging than a light frost at 32 °F, so the 50 % hard-frost dates of April 15 and October 25 are used to gauge the risk of severe freezing injury.

How to read the probabilities

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

  • Spring: "10% after May 12" 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 September 30" 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 Paw Paw, ILNumbered nearest stations: 1 — Rochelle, IL — 18 mi; 2 — De Kalb, IL — 21 mi; 3 — Peru, IL — 23 mi; 4 — Ottawa, IL — 24 mi; 5 — Princeton, IL — 32 mi.IAIN25 mi · 40 km1. Rochelle, IL — 18 mi12. De Kalb, IL — 21 mi23. Peru, IL — 23 mi34. Ottawa, IL — 24 mi45. Princeton, IL — 32 mi5
  1. Rochelle, IL 18 mi (28 km)
  2. De Kalb, IL 21 mi (34 km)
  3. Peru, IL 23 mi (37 km)
  4. Ottawa, IL 24 mi (38 km)
  5. Princeton, IL 32 mi (52 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 41.6653, -88.9781.