U.S. Frost Dates by Weather Station

NOAA station USC00131060 · Iowa

Frost Dates near Burlington, IA

NOAA weather station Burlington 2 S (USC00131060), Iowa · elevation 690 ft (210 m) · hardiness zone 6a*

Burlington is the nearest town to the station (2.3 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 May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 1850% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season185 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season near Burlington, IASpring: a frost after April 3 in 9 years out of 10, after April 18 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 185 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 18First frost ~Oct 20Frost season near Burlington, IASpring: a frost after April 3 in 9 years out of 10, after April 18 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 185 days.JFMAMJJASONDLast frost ~Apr 18First frost ~Oct 20
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 3October 6
50% (typical)April 18October 20
90% (likely)April 3November 2
Frost-free season (32°F, 50% chance)
185 days
Hard frost (28°F), last in spring, 50% chance after
April 7
Hard frost (28°F), first in fall, 50% chance before
October 31

The last 15 years (2006–2020 normals)

Typical last frost April 15 (3 days earlier than the 30-year normal), typical first fall frost October 26 (6 days later). Frost-free season 191 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 Burlington: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 29, 30% April 24, 40% April 21, 50% April 18, 60% April 14, 70% April 11, 80% April 8, 90% April 3. Observed last spring frost in recent years: 2021 April 23, 2022 April 27, 2024 April 21, 2025 April 9, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 3Apr 18Apr 32021: April 232022: April 272024: April 212025: April 92026: April 20Fall near Burlington: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 12, 30% October 15, 40% October 18, 50% October 20, 60% October 23, 70% October 25, 80% October 29, 90% November 2. Observed first fall frost in recent years: 2021 November 1, 2022 October 16, 2023 October 30, 2024 October 16, 2025 November 2.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 20Nov 22021: November 12022: October 162023: October 302024: October 162025: 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 23November 1
2022April 27October 16
2023incomplete recordOctober 30
2024April 21October 16
2025April 9November 2
2026April 20season not over yet

What these dates mean

May 3 is the cautious spring date, with a 10 % chance of a light frost later; it lets a gardener plan to set out tender crops when the risk is low. The 50 % date is April 18, meaning there is a 50 % chance of a light frost later than this date. The median hard-frost date is April 7, indicating an even chance of a 28 °F event.

October 6 is the cautious fall date, carrying a 10 % chance of a light frost earlier; it guides a gardener to finish harvesting tender crops before frost becomes likely. The 50 % date is October 20, meaning there is a 50 % chance of a light frost earlier than this date. The median hard-frost date is October 31, showing an even chance of a 28 °F event.

A hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so its timing is especially critical for protecting tender crops.

How to read the probabilities

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

  • Spring: "10% after May 3" 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 6" 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 Burlington, IANumbered nearest stations: 1 — Burlington (Airport), IA — 1 mi; 2 — near Oquawka, IL — 9 mi; 3 — Fort Madison, IA — 16 mi; 4 — Mount Pleasant, IA — 26 mi; 5 — Monmouth, IL — 28 mi.ILMO25 mi · 40 km1. Burlington (Airport), IA — 1 mi12. near Oquawka, IL — 9 mi23. Fort Madison, IA — 16 mi34. Mount Pleasant, IA — 26 mi45. Monmouth, IL — 28 mi5
  1. Burlington (Airport), IA 1 mi (1 km)
  2. near Oquawka, IL 9 mi (14 km)
  3. Fort Madison, IA 16 mi (25 km)
  4. Mount Pleasant, IA 26 mi (42 km)
  5. Monmouth, IL 28 mi (44 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: 40.7747, -91.1164.