U.S. Frost Dates by Weather Station

NOAA station USC00107208 · Idaho

Frost Dates near Pocatello, ID

NOAA weather station Pocatello 2 NE (USC00107208), Idaho · elevation 4832 ft (1473 m) · hardiness zone 6b*

Pocatello is the nearest town to the station (2.4 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter June 6only 1 spring in 10 still has a frost later
  • Typical last frostMay 1650% chance of a frost after it
  • Typical first fall frostOctober 250% chance of a frost before it
  • Frost-free season137 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season near Pocatello, IDSpring: a frost after April 30 in 9 years out of 10, after May 16 in half of the years, after June 6 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before October 2 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 137 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 16First frost ~Oct 2Frost season near Pocatello, IDSpring: a frost after April 30 in 9 years out of 10, after May 16 in half of the years, after June 6 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before October 2 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 137 days.JFMAMJJASONDLast frost ~May 16First frost ~Oct 2
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 6September 14
50% (typical)May 16October 2
90% (likely)April 30October 18
Frost-free season (32°F, 50% chance)
137 days
Hard frost (28°F), last in spring, 50% chance after
May 1
Hard frost (28°F), first in fall, 50% chance before
October 13

The last 15 years (2006–2020 normals)

Typical last frost May 16 (same as the 30-year normal), typical first fall frost October 6 (4 days later). Frost-free season 141 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 near Pocatello: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 6, 20% May 31, 30% May 25, 40% May 20, 50% May 16, 60% May 12, 70% May 8, 80% May 4, 90% April 30.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 6May 16Apr 30Fall near Pocatello: chance of a frost before this dateFall, chance of a frost before the date: 10% September 14, 20% September 21, 30% September 26, 40% September 29, 50% October 2, 60% October 5, 70% October 9, 80% October 13, 90% October 18.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Nov 1Sep 14Oct 2Oct 18
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 14 marks the cautious fall date for finishing the harvest of tender crops in the Pocatello area; only a 10 % chance exists that a light frost has arrived earlier. In spring, gardeners who prefer a low risk wait until June 6 to set out tender crops, the cautious light-frost date with a 10 % chance of frost later.

The median light-frost dates are May 16 in spring and October 2 in fall, each representing an even 50 % chance of frost on either side of the date.

The hard-frost 50 % dates are May 1 in spring and October 13 in fall; a hard frost (28 °F) can damage plants that survive a light frost (32 °F) because the lower temperature is more destructive. These dates reflect the 26-year record for the station and give gardeners a clear risk reference for planning their season.

How to read the probabilities

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

  • Spring: "10% after June 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 September 14" 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, IDNumbered nearest stations: 1 — Pocatello (Airport), ID — 8 mi; 2 — Fort Hall, ID — 10 mi; 3 — Idaho Falls 46 W, ID — 52 mi; 4 — Minidoka Dam, ID — 57 mi; 5 — Preston, ID — 61 mi.WYUT25 mi · 40 km1. Pocatello (Airport), ID — 8 mi12. Fort Hall, ID — 10 mi23. Idaho Falls 46 W, ID — 52 mi34. Minidoka Dam, ID — 57 mi45. Preston, ID — 61 mi5
  1. Pocatello (Airport), ID 8 mi (14 km)
  2. Fort Hall, ID 10 mi (17 km)
  3. Idaho Falls 46 W, ID 52 mi (83 km)
  4. Minidoka Dam, ID 57 mi (92 km)
  5. Preston, ID 61 mi (99 km)

Sources

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

Station coordinates: 42.8917, -112.4086.