U.S. Frost Dates by Weather Station

NOAA station USC00135131 · Iowa

Frost Dates for Maquoketa, IA

NOAA weather station Maquoketa (USC00135131), Iowa · elevation 668 ft (204 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2550% chance of a frost after it
  • Typical first fall frostOctober 1450% chance of a frost before it
  • Frost-free season171 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Maquoketa, IASpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 9 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 26 in 9 years out of 10. Typical frost-free season: 171 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 25First frost ~Oct 14Frost season at Maquoketa, IASpring: a frost after April 11 in 9 years out of 10, after April 25 in half of the years, after May 9 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 26 in 9 years out of 10. Typical frost-free season: 171 days.JFMAMJJASONDLast frost ~Apr 25First 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 9September 30
50% (typical)April 25October 14
90% (likely)April 11October 26
Frost-free season (32°F, 50% chance)
171 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
October 24

The last 15 years (2006–2020 normals)

Typical last frost April 27 (2 days later than the 30-year normal), typical first fall frost October 16 (2 days later). Frost-free season 173 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 Maquoketa: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 5, 30% May 2, 40% April 29, 50% April 25, 60% April 22, 70% April 18, 80% April 15, 90% April 11. Observed last spring frost in recent years: 2021 April 25, 2022 April 28, 2023 April 27.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 25Apr 112021: April 252022: April 282023: April 27Fall at Maquoketa: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 5, 30% October 9, 40% October 12, 50% October 14, 60% October 16, 70% October 19, 80% October 22, 90% October 26. Observed first fall frost in recent years: 2021 October 23, 2022 October 8, 2023 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 14Oct 262021: October 232022: October 82023: October 10
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 23
2022April 28October 8
2023April 27October 10
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

The cautious fall date in Maquoketa for finishing the harvest is September 30, when there is only a 10 % chance a light frost has arrived. Gardeners who want to be cautious wait until after September 30 to finish tender crops.

In spring, the cautious date for setting out tender crops is May 9, a 10 % chance of a frost later than that date; planting earlier on April 11 carries a 90 % chance of frost and is a gamble. The 50% light-frost date in spring is April 25; there is a 50 % chance of a frost later than this date. The 50% light-frost date in fall is October 14; there is a 50 % chance of a frost earlier than this date.

The median hard-frost dates are April 14 and October 24, and a hard frost at 28 °F can damage plants more severely than 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 9" 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 Maquoketa, IANumbered nearest stations: 1 — near Bellevue, IA — 18 mi; 2 — Dubuque, IA — 22 mi; 3 — Cascade, IA — 23 mi; 4 — near Camanche, IA — 28 mi; 5 — Dubuque Lock and Dam 11, IA — 32 mi.IAILWI25 mi · 40 km1. near Bellevue, IA — 18 mi12. Dubuque, IA — 22 mi23. Cascade, IA — 23 mi34. near Camanche, IA — 28 mi45. Dubuque Lock and Dam 11, IA — 32 mi5
  1. near Bellevue, IA 18 mi (29 km)
  2. Dubuque, IA 22 mi (36 km)
  3. Cascade, IA 23 mi (38 km)
  4. near Camanche, IA 28 mi (46 km)
  5. Dubuque Lock and Dam 11, IA 32 mi (51 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: 42.0772, -90.6647.