U.S. Frost Dates by Weather Station

NOAA station USW00024156 · Idaho

Frost Dates for Pocatello (Airport), ID

NOAA weather station Pocatello Regional Airport (USW00024156), Idaho · elevation 4478 ft (1365 m) · hardiness zone 6a*

  • Lower-risk planting dateafter June 13only 1 spring in 10 still has a frost later
  • Typical last frostMay 2350% chance of a frost after it
  • Typical first fall frostSeptember 1850% chance of a frost before it
  • Frost-free season117 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Pocatello (Airport), IDSpring: a frost after May 6 in 9 years out of 10, after May 23 in half of the years, after June 13 in 1 year out of 10. Fall: the first frost comes before September 3 in 1 year out of 10, before September 18 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 117 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 23First frost ~Sep 18Frost season at Pocatello (Airport), IDSpring: a frost after May 6 in 9 years out of 10, after May 23 in half of the years, after June 13 in 1 year out of 10. Fall: the first frost comes before September 3 in 1 year out of 10, before September 18 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 117 days.JFMAMJJASONDLast frost ~May 23First frost ~Sep 18
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)June 13September 3
50% (typical)May 23September 18
90% (likely)May 6October 4
Frost-free season (32°F, 50% chance)
117 days
Hard frost (28°F), last in spring, 50% chance after
May 6
Hard frost (28°F), first in fall, 50% chance before
October 1

The last 15 years (2006–2020 normals)

Typical last frost May 21 (2 days earlier than the 30-year normal), typical first fall frost September 19 (1 day later). Frost-free season 120 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 Pocatello (Airport): chance of a frost after this dateSpring, chance of a frost after the date: 10% June 13, 20% June 7, 30% June 2, 40% May 28, 50% May 23, 60% May 18, 70% May 15, 80% May 11, 90% May 6. Observed last spring frost in recent years: 2021 May 12, 2022 May 24, 2023 June 22, 2024 June 19, 2025 June 23, 2026 June 11.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 13May 23May 62021: May 122022: May 242023: June 222024: June 192025: June 232026: June 11Fall at Pocatello (Airport): chance of a frost before this dateFall, chance of a frost before the date: 10% September 3, 20% September 8, 30% September 12, 40% September 15, 50% September 18, 60% September 21, 70% September 25, 80% September 29, 90% October 4. Observed first fall frost in recent years: 2021 September 17, 2022 October 13, 2023 October 13, 2024 October 1, 2025 October 6.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 3Sep 18Oct 42021: September 172022: October 132023: October 132024: October 12025: October 6
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
2021May 12September 17
2022May 24October 13
2023June 22October 13
2024June 19October 1
2025June 23October 6
2026June 11season not over yet

What these dates mean

The cautious spring date for Pocatello (Airport) is June 13, when only a 10 % chance of a light frost remains; a gardener can use this date to set out tender crops with minimal risk of a late freeze.

The 50 % dates are May 23 in spring and September 18 in fall; on each of those days the chance of a frost is even, so they mark the middle of the frost-risk window. For a conservative schedule, the cautious fall date is September 3, when there is only a 10 % chance that a light frost has already arrived, allowing harvest of tender crops to be completed. The hard-frost 50 % dates are May 6 and October 1, 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 June 13" 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 3" 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 Pocatello (Airport), IDNumbered nearest stations: 1 — near Pocatello, ID — 8 mi; 2 — Fort Hall, ID — 12 mi; 3 — Idaho Falls 46 W, ID — 46 mi; 4 — Minidoka Dam, ID — 50 mi; 5 — Paul, ID — 64 mi.ID25 mi · 40 km1. near Pocatello, ID — 8 mi12. Fort Hall, ID — 12 mi23. Idaho Falls 46 W, ID — 46 mi34. Minidoka Dam, ID — 50 mi45. Paul, ID — 64 mi5
  1. near Pocatello, ID 8 mi (14 km)
  2. Fort Hall, ID 12 mi (19 km)
  3. Idaho Falls 46 W, ID 46 mi (74 km)
  4. Minidoka Dam, ID 50 mi (81 km)
  5. Paul, ID 64 mi (103 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 42.9203, -112.5711.