U.S. Frost Dates by Weather Station

NOAA station USW00024133 · Idaho

Frost Dates for Burley, ID

NOAA weather station Burley Municipal Airport (USW00024133), Idaho · elevation 4142 ft (1263 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 23only 1 spring in 10 still has a frost later
  • Typical last frostMay 750% chance of a frost after it
  • Typical first fall frostOctober 450% chance of a frost before it
  • Frost-free season150 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Burley, IDSpring: a frost after April 23 in 9 years out of 10, after May 7 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 150 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 7First frost ~Oct 4Frost season at Burley, IDSpring: a frost after April 23 in 9 years out of 10, after May 7 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 150 days.JFMAMJJASONDLast frost ~May 7First frost ~Oct 4
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 23September 21
50% (typical)May 7October 4
90% (likely)April 23October 18
Frost-free season (32°F, 50% chance)
150 days
Hard frost (28°F), last in spring, 50% chance after
April 21
Hard frost (28°F), first in fall, 50% chance before
October 17

The last 15 years (2006–2020 normals)

Typical last frost May 7 (same as the 30-year normal), typical first fall frost October 7 (3 days later). Frost-free season 152 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 Burley: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 23, 20% May 15, 30% May 12, 40% May 9, 50% May 7, 60% May 4, 70% May 1, 80% April 28, 90% April 23. Observed last spring frost in recent years: 2021 May 11, 2022 May 23, 2023 May 8, 2024 May 5, 2025 May 1, 2026 May 1.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 23May 7Apr 232021: May 112022: May 232023: May 82024: May 52025: May 12026: May 1Fall at Burley: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 26, 30% September 29, 40% October 1, 50% October 4, 60% October 7, 70% October 10, 80% October 14, 90% October 18. Observed first fall frost in recent years: 2021 September 29, 2022 October 15, 2023 October 26, 2024 October 18, 2025 October 7.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 21Oct 4Oct 182021: September 292022: October 152023: October 262024: October 182025: October 7
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 11September 29
2022May 23October 15
2023May 8October 26
2024May 5October 18
2025May 1October 7
2026May 1season not over yet

What these dates mean

In Burley the first fall frost (32 °F) has a 50 % chance of occurring before October 4, making that the typical date for gardeners to expect a frost. The cautious date to finish harvesting tender crops is the early date of September 21, when there is only a 10 % chance of a frost having arrived. Counting on tender crops through the late date of October 18 is a gamble because a frost is 90 % likely before then.

The last spring frost (32 °F) shows a 50 % chance of occurring after May 7, which is the typical date for planting tender crops. A cautious planting plan waits until the late date of May 23, when the chance of a frost after that date drops to 10 %; sowing before the early date of April 23 would be a gamble with a 90 % chance of frost. A hard frost (28 °F) matters more than a light frost because it can damage or kill plants that survive a 32 °F frost.

How to read the probabilities

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

  • Spring: "10% after May 23" 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 21" 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 Burley, IDNumbered nearest stations: 1 — Paul, ID — 5 mi; 2 — Minidoka Dam, ID — 16 mi; 3 — Hazelton, ID — 19 mi; 4 — Oakley, ID — 22 mi; 5 — Richfield, ID — 40 mi.UT25 mi · 40 km1. Paul, ID — 5 mi12. Minidoka Dam, ID — 16 mi23. Hazelton, ID — 19 mi34. Oakley, ID — 22 mi45. Richfield, ID — 40 mi5
  1. Paul, ID 5 mi (8 km)
  2. Minidoka Dam, ID 16 mi (26 km)
  3. Hazelton, ID 19 mi (31 km)
  4. Oakley, ID 22 mi (36 km)
  5. Richfield, ID 40 mi (65 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: 42.5417, -113.7661.