U.S. Frost Dates by Weather Station

NOAA station USC00130576 · Iowa

Frost Dates for Bedford, IA

NOAA weather station Bedford (USC00130576), Iowa · elevation 1190 ft (363 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 6only 1 spring in 10 still has a frost later
  • Typical last frostApril 2450% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season173 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Bedford, IASpring: a frost after April 9 in 9 years out of 10, after April 24 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 173 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 24First frost ~Oct 15Frost season at Bedford, IASpring: a frost after April 9 in 9 years out of 10, after April 24 in half of the years, after May 6 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 173 days.JFMAMJJASONDLast frost ~Apr 24First frost ~Oct 15
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.Today

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 6October 1
50% (typical)April 24October 15
90% (likely)April 9October 29
Frost-free season (32°F, 50% chance)
173 days
Hard frost (28°F), last in spring, 50% chance after
April 14
Hard frost (28°F), first in fall, 50% chance before
October 26

The last 15 years (2006–2020 normals)

Typical last frost April 23 (1 day earlier than the 30-year normal), typical first fall frost October 18 (3 days later). Frost-free season 178 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 Bedford: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 6, 20% May 3, 30% April 30, 40% April 27, 50% April 24, 60% April 21, 70% April 17, 80% April 13, 90% April 9.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 6Apr 24Apr 9Fall at Bedford: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 5, 30% October 9, 40% October 12, 50% October 15, 60% October 18, 70% October 21, 80% October 24, 90% October 29.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 15Oct 29
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

The 173 days between the 50% dates in Bedford frame the interval when frost risk is balanced. In this location the spring 50% date is April 24 and the fall 50% date is October 15; at each of these dates the chance of a light frost occurring later (spring) or earlier (fall) is 50 percent, but they are not frost dates themselves.

For a cautious plan a gardener would wait until the May 6 date in spring, which carries only a 10 % chance of a light frost later, before setting out tender crops. In the fall the equally cautious point is October 1, when there is just a 10 % chance that a light frost has already arrived, marking the last safe day to finish harvesting tender crops.

Hard frosts at 28 °F, recorded by the median dates April 14 and October 26, can damage plants more severely than the milder 32 °F light frosts.

How to read the probabilities

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

  • Spring: "10% after May 6" 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 October 1" 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 Bedford, IANumbered nearest stations: 1 — Clarinda, IA — 16 mi; 2 — Maryville, MO — 23 mi; 3 — Mount Ayr, IA — 25 mi; 4 — Conception, MO — 30 mi; 5 — Creston, IA — 30 mi.MONE25 mi · 40 km1. Clarinda, IA — 16 mi12. Maryville, MO — 23 mi23. Mount Ayr, IA — 25 mi34. Conception, MO — 30 mi45. Creston, IA — 30 mi5
  1. Clarinda, IA 16 mi (25 km)
  2. Maryville, MO 23 mi (38 km)
  3. Mount Ayr, IA 25 mi (41 km)
  4. Conception, MO 30 mi (48 km)
  5. Creston, IA 30 mi (49 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: 40.6742, -94.7244.