U.S. Frost Dates by Weather Station

NOAA station USC00106877 · Idaho

Frost Dates for Paul, ID

NOAA weather station Paul 1 ENE (USC00106877), Idaho · elevation 4150 ft (1265 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 22only 1 spring in 10 still has a frost later
  • Typical last frostMay 650% chance of a frost after it
  • Typical first fall frostOctober 650% chance of a frost before it
  • Frost-free season151 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Paul, IDSpring: a frost after April 23 in 9 years out of 10, after May 6 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 6 in half of the years, before October 19 in 9 years out of 10. Typical frost-free season: 151 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 6First frost ~Oct 6Frost season at Paul, IDSpring: a frost after April 23 in 9 years out of 10, after May 6 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 22 in 1 year out of 10, before October 6 in half of the years, before October 19 in 9 years out of 10. Typical frost-free season: 151 days.JFMAMJJASONDLast frost ~May 6First frost ~Oct 6
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)May 22September 22
50% (typical)May 6October 6
90% (likely)April 23October 19
Frost-free season (32°F, 50% chance)
151 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 18

The last 15 years (2006–2020 normals)

Typical last frost May 7 (1 day later than the 30-year normal), typical first fall frost October 9 (3 days later). Frost-free season 153 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 Paul: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 22, 20% May 16, 30% May 13, 40% May 9, 50% May 6, 60% May 3, 70% April 30, 80% April 28, 90% April 23.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 22May 6Apr 23Fall at Paul: chance of a frost before this dateFall, chance of a frost before the date: 10% September 22, 20% September 27, 30% September 30, 40% October 3, 50% October 6, 60% October 9, 70% October 13, 80% October 16, 90% October 19.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 22Oct 6Oct 19
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

May 22 is the cautious spring date in Paul, giving gardeners a low-risk moment to set out tender crops. The 50% light-frost date in spring is May 6, marking an even chance that a frost will occur. For hard frost, the median date is April 22, indicating a 50 % chance of temperatures reaching 28 °F.

September 22 serves as the cautious fall date, indicating a low probability of an early frost and a good time to finish harvesting tender crops. The 50% light-frost date in fall is October 6, the point where frost odds are even, while the median hard-frost date is October 18. A hard frost at 28 °F can damage plants that would survive a light frost at 32 °F. The two 32°F 50% dates are 151 days apart, marking the span of roughly even frost odds.

How to read the probabilities

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

  • Spring: "10% after May 22" 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 22" 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 Paul, IDNumbered nearest stations: 1 — Burley, ID — 5 mi; 2 — Minidoka Dam, ID — 14 mi; 3 — Hazelton, ID — 19 mi; 4 — Oakley, ID — 27 mi; 5 — Richfield, ID — 36 mi.UT25 mi · 40 km1. Burley, ID — 5 mi12. Minidoka Dam, ID — 14 mi23. Hazelton, ID — 19 mi34. Oakley, ID — 27 mi45. Richfield, ID — 36 mi5
  1. Burley, ID 5 mi (8 km)
  2. Minidoka Dam, ID 14 mi (23 km)
  3. Hazelton, ID 19 mi (31 km)
  4. Oakley, ID 27 mi (43 km)
  5. Richfield, ID 36 mi (58 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: 42.6117, -113.7628.