U.S. Frost Dates by Weather Station

NOAA station USC00136719 · Iowa

Frost Dates for Pocahontas, IA

NOAA weather station Pocahontas (USC00136719), Iowa · elevation 1212 ft (369 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 8only 1 spring in 10 still has a frost later
  • Typical last frostApril 2650% chance of a frost after it
  • Typical first fall frostOctober 750% chance of a frost before it
  • Frost-free season164 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Pocahontas, IASpring: a frost after April 11 in 9 years out of 10, after April 26 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 7 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 164 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 26First frost ~Oct 7Frost season at Pocahontas, IASpring: a frost after April 11 in 9 years out of 10, after April 26 in half of the years, after May 8 in 1 year out of 10. Fall: the first frost comes before September 25 in 1 year out of 10, before October 7 in half of the years, before October 20 in 9 years out of 10. Typical frost-free season: 164 days.JFMAMJJASONDLast frost ~Apr 26First frost ~Oct 7
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 8September 25
50% (typical)April 26October 7
90% (likely)April 11October 20
Frost-free season (32°F, 50% chance)
164 days
Hard frost (28°F), last in spring, 50% chance after
April 16
Hard frost (28°F), first in fall, 50% chance before
October 17

The last 15 years (2006–2020 normals)

Typical last frost April 27 (1 day later than the 30-year normal), typical first fall frost October 9 (2 days later). Frost-free season 165 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 Pocahontas: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 8, 20% May 4, 30% May 2, 40% April 30, 50% April 26, 60% April 23, 70% April 20, 80% April 16, 90% April 11. Observed last spring frost in recent years: 2021 April 25, 2022 May 4, 2023 April 26, 2024 April 22, 2025 April 16.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 8Apr 26Apr 112021: April 252022: May 42023: April 262024: April 222025: April 16Fall at Pocahontas: chance of a frost before this dateFall, chance of a frost before the date: 10% September 25, 20% September 29, 30% October 1, 40% October 4, 50% October 7, 60% October 10, 70% October 12, 80% October 15, 90% October 20. Observed first fall frost in recent years: 2021 October 22, 2022 September 28, 2023 October 10, 2024 October 15.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 25Oct 7Oct 202021: October 222022: September 282023: October 102024: October 15
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 25October 22
2022May 4September 28
2023April 26October 10
2024April 22October 15
2025April 16incomplete record
2026incomplete recordseason not over yet

What these dates mean

May 8 is the cautious spring light-frost date, so a gardener can plan to set out tender crops after that day with only a 10 % chance of a later frost. The cautious fall date is September 25, indicating a 10 % chance that a light frost has arrived earlier, so tender crops should be finished by then.

April 26 carries a 50 % chance of a light frost later than that date, while October 7 carries a 50 % chance of a light frost earlier than that date; these median dates mark the point where frost risk is even. The median hard-frost dates are April 16 and October 17, and a hard frost at 28 °F can damage plant tissues that survive a 32 °F light frost, making it the more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 8" 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 25" 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 Pocahontas, IANumbered nearest stations: 1 — Rockwell City, IA — 23 mi; 2 — Sioux Rapids, IA — 23 mi; 3 — Fort Dodge, IA — 25 mi; 4 — Sac City, IA — 27 mi; 5 — Storm Lake, IA — 28 mi.25 mi · 40 km1. Rockwell City, IA — 23 mi12. Sioux Rapids, IA — 23 mi23. Fort Dodge, IA — 25 mi34. Sac City, IA — 27 mi45. Storm Lake, IA — 28 mi5
  1. Rockwell City, IA 23 mi (37 km)
  2. Sioux Rapids, IA 23 mi (38 km)
  3. Fort Dodge, IA 25 mi (41 km)
  4. Sac City, IA 27 mi (43 km)
  5. Storm Lake, IA 28 mi (44 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: 42.7292, -94.6614.