U.S. Frost Dates by Weather Station

NOAA station USC00132724 · Iowa

Frost Dates for Estherville, IA

NOAA weather station Estherville 4 E (USC00132724), Iowa · elevation 1320 ft (402 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 14only 1 spring in 10 still has a frost later
  • Typical last frostMay 250% chance of a frost after it
  • Typical first fall frostOctober 350% chance of a frost before it
  • Frost-free season153 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Estherville, IASpring: a frost after April 18 in 9 years out of 10, after May 2 in half of the years, after May 14 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 153 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 2First frost ~Oct 3Frost season at Estherville, IASpring: a frost after April 18 in 9 years out of 10, after May 2 in half of the years, after May 14 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 153 days.JFMAMJJASONDLast frost ~May 2First frost ~Oct 3
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 14September 20
50% (typical)May 2October 3
90% (likely)April 18October 17
Frost-free season (32°F, 50% chance)
153 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 14

The last 15 years (2006–2020 normals)

Typical last frost May 2 (same as the 30-year normal), typical first fall frost October 6 (3 days later). Frost-free season 157 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 Estherville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 14, 20% May 10, 30% May 7, 40% May 4, 50% May 2, 60% April 30, 70% April 27, 80% April 23, 90% April 18. Observed last spring frost in recent years: 2021 May 11, 2022 April 28, 2023 May 3, 2024 April 24.Spring: last frostChance of a frost after this date10%50%90%May 1May 14May 2Apr 182021: May 112022: April 282023: May 32024: April 24Fall at Estherville: chance of a frost before this dateFall, chance of a frost before the date: 10% September 20, 20% September 25, 30% September 28, 40% October 1, 50% October 3, 60% October 5, 70% October 9, 80% October 12, 90% October 17. Observed first fall frost in recent years: 2021 October 23, 2022 September 28, 2023 October 10, 2024 October 14.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 20Oct 3Oct 172021: October 232022: September 282023: October 102024: October 14
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 28September 28
2023May 3October 10
2024April 24October 14
2025incomplete recordincomplete record
2026incomplete recordseason not over yet

What these dates mean

May 14 is the cautious spring date in Estherville, and it gives a gardener the chance to set out tender crops with only a 10% chance of a light frost occurring later.

The 50% spring date is May 2, indicating an even-odds point for a light frost, while the 50% fall date is October 3, marking an even-odds point for a light frost in autumn. September 20 is the cautious fall date, providing a 10% chance that a light frost has already arrived and signaling when tender crops should be finished. The 50% hard-frost dates are April 22 in spring and October 14 in fall.

A hard frost at 28 °F can damage plants that survive a light frost at 32 °F, so the hard-frost dates are especially important for protecting vulnerable 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 14" 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 20" 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 Estherville, IANumbered nearest stations: 1 — Milford, IA — 22 mi; 2 — Spencer, IA — 26 mi; 3 — Lake Park, IA — 29 mi; 4 — Windom, MN — 38 mi; 5 — Winnebago, MN — 38 mi.MNIA25 mi · 40 km1. Milford, IA — 22 mi12. Spencer, IA — 26 mi23. Lake Park, IA — 29 mi34. Windom, MN — 38 mi45. Winnebago, MN — 38 mi5
  1. Milford, IA 22 mi (35 km)
  2. Spencer, IA 26 mi (42 km)
  3. Lake Park, IA 29 mi (47 km)
  4. Windom, MN 38 mi (60 km)
  5. Winnebago, MN 38 mi (62 km)

Sources

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

Station coordinates: 43.4036, -94.7472.