U.S. Frost Dates by Weather Station

NOAA station USC00131962 · Iowa

Frost Dates for Creston, IA

NOAA weather station Creston 2 SW (USC00131962), Iowa · elevation 1296 ft (395 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2850% chance of a frost after it
  • Typical first fall frostOctober 1150% chance of a frost before it
  • Frost-free season164 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Creston, IASpring: a frost after April 14 in 9 years out of 10, after April 28 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 11 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 164 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 28First frost ~Oct 11Frost season at Creston, IASpring: a frost after April 14 in 9 years out of 10, after April 28 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before September 24 in 1 year out of 10, before October 11 in half of the years, before October 26 in 9 years out of 10. Typical frost-free season: 164 days.JFMAMJJASONDLast frost ~Apr 28First frost ~Oct 11
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 9September 24
50% (typical)April 28October 11
90% (likely)April 14October 26
Frost-free season (32°F, 50% chance)
164 days
Hard frost (28°F), last in spring, 50% chance after
April 17
Hard frost (28°F), first in fall, 50% chance before
October 23

The last 15 years (2006–2020 normals)

Typical last frost April 27 (1 day earlier than the 30-year normal), typical first fall frost October 15 (4 days later). Frost-free season 171 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 Creston: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 6, 30% May 3, 40% May 1, 50% April 28, 60% April 25, 70% April 22, 80% April 18, 90% April 14.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 28Apr 14Fall at Creston: chance of a frost before this dateFall, chance of a frost before the date: 10% September 24, 20% September 30, 30% October 4, 40% October 8, 50% October 11, 60% October 14, 70% October 17, 80% October 21, 90% October 26.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 24Oct 11Oct 26
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.

What these dates mean

September 24 is the cautious fall date for finishing the harvest of tender crops in Creston, since there is only a 10 % chance that a light frost has arrived earlier. The 50% date is October 11, meaning a gardener faces an even chance of a frost before that day, while the 90 % date of October 26 signals a high risk for crops kept that late.

In spring, the cautious date for setting out tender crops is May 9, when the chance of a light frost later is just 10 %; the 50% date of April 28 marks an even-odds point, and April 14 carries a 90 % chance and is a gamble. Hard-frost dates, with a 50 % chance at 28 °F, are April 17 in spring and October 23 in fall; a hard frost can damage plant tissue that would survive a light frost. The 164-day span between the two 32 °F 50 % dates reflects the length of the median frost-free period.

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 24" 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 Creston, IANumbered nearest stations: 1 — Greenfield, IA — 18 mi; 2 — Beaconsfield, IA — 24 mi; 3 — Mount Ayr, IA — 24 mi; 4 — Bedford, IA — 30 mi; 5 — Osceola, IA — 34 mi.MO25 mi · 40 km1. Greenfield, IA — 18 mi12. Beaconsfield, IA — 24 mi23. Mount Ayr, IA — 24 mi34. Bedford, IA — 30 mi45. Osceola, IA — 34 mi5
  1. Greenfield, IA 18 mi (29 km)
  2. Beaconsfield, IA 24 mi (39 km)
  3. Mount Ayr, IA 24 mi (39 km)
  4. Bedford, IA 30 mi (49 km)
  5. Osceola, IA 34 mi (54 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: 41.0372, -94.3936.