U.S. Frost Dates by Weather Station

NOAA station USC00136151 · Iowa

Frost Dates for Oakland, IA

NOAA weather station Oakland (USC00136151), Iowa · elevation 1260 ft (384 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 5only 1 spring in 10 still has a frost later
  • Typical last frostApril 2350% chance of a frost after it
  • Typical first fall frostOctober 1450% chance of a frost before it
  • Frost-free season174 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Oakland, IASpring: a frost after April 10 in 9 years out of 10, after April 23 in half of the years, after May 5 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 14 in half of the years, before October 27 in 9 years out of 10. Typical frost-free season: 174 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 23First frost ~Oct 14Frost season at Oakland, IASpring: a frost after April 10 in 9 years out of 10, after April 23 in half of the years, after May 5 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 14 in half of the years, before October 27 in 9 years out of 10. Typical frost-free season: 174 days.JFMAMJJASONDLast frost ~Apr 23First frost ~Oct 14
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 5September 30
50% (typical)April 23October 14
90% (likely)April 10October 27
Frost-free season (32°F, 50% chance)
174 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 23 (same as the 30-year normal), typical first fall frost October 19 (5 days later). Frost-free season 179 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 Oakland: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 5, 20% May 1, 30% April 29, 40% April 26, 50% April 23, 60% April 21, 70% April 18, 80% April 15, 90% April 10. Observed last spring frost in recent years: 2021 April 23, 2022 April 27, 2023 April 24, 2024 April 22, 2025 April 9, 2026 April 20.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 5Apr 23Apr 102021: April 232022: April 272023: April 242024: April 222025: April 92026: April 20Fall at Oakland: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 4, 30% October 8, 40% October 12, 50% October 14, 60% October 17, 70% October 21, 80% October 23, 90% October 27. Observed first fall frost in recent years: 2021 October 22, 2022 October 9, 2023 October 28, 2024 October 16, 2025 October 30.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 14Oct 272021: October 222022: October 92023: October 282024: October 162025: October 30
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 23October 22
2022April 27October 9
2023April 24October 28
2024April 22October 16
2025April 9October 30
2026April 20season not over yet

What these dates mean

May 5 is the cautious spring date for light frost in Oakland; with only a 10 % chance of a frost later, it signals when a gardener can plan to set out tender crops with minimal risk.

April 23 is the 50 % date for light frost in spring, meaning the chance of a frost is fifty-fifty on that day. October 14 is the 50 % date for light frost in fall, also marking a fifty-percent chance of a frost. September 30 is the cautious fall date, offering a 10 % chance of a frost earlier and therefore the point at which a gardener can finish harvesting tender crops before frost becomes likely.

The hard-frost 28 °F dates—April 15 in spring and October 25 in fall—are noted because a hard frost can damage plant tissue that survives 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 5" 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 Oakland, IANumbered nearest stations: 1 — Atlantic, IA — 21 mi; 2 — Red Oak, IA — 22 mi; 3 — near Omaha, NE — 27 mi; 4 — Logan, IA — 31 mi; 5 — Audubon, IA — 37 mi.NE25 mi · 40 km1. Atlantic, IA — 21 mi12. Red Oak, IA — 22 mi23. near Omaha, NE — 27 mi34. Logan, IA — 31 mi45. Audubon, IA — 37 mi5
  1. Atlantic, IA 21 mi (34 km)
  2. Red Oak, IA 22 mi (36 km)
  3. near Omaha, NE 27 mi (43 km)
  4. Logan, IA 31 mi (50 km)
  5. Audubon, IA 37 mi (59 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: 41.3044, -95.3844.