U.S. Frost Dates by Weather Station

NOAA station USC00456262 · Washington

Frost Dates for Packwood, WA

NOAA weather station Packwood (USC00456262), Washington · elevation 1060 ft (323 m) · hardiness zone 8a*

  • Lower-risk planting dateafter May 17only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 850% chance of a frost before it
  • Frost-free season162 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season at Packwood, WASpring: a frost after April 12 in 9 years out of 10, after April 30 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 8 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 162 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 8Frost season at Packwood, WASpring: a frost after April 12 in 9 years out of 10, after April 30 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 8 in half of the years, before October 31 in 9 years out of 10. Typical frost-free season: 162 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 8
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 17September 21
50% (typical)April 30October 8
90% (likely)April 12October 31
Frost-free season (32°F, 50% chance)
162 days
Hard frost (28°F), last in spring, 50% chance after
April 6
Hard frost (28°F), first in fall, 50% chance before
October 29

The last 15 years (2006–2020 normals)

Typical last frost April 28 (2 days earlier than the 30-year normal), typical first fall frost October 10 (2 days later). Frost-free season 165 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 Packwood: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 17, 20% May 12, 30% May 7, 40% May 3, 50% April 30, 60% April 27, 70% April 23, 80% April 19, 90% April 12.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 17Apr 30Apr 12Fall at Packwood: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 28, 30% October 2, 40% October 5, 50% October 8, 60% October 13, 70% October 17, 80% October 23, 90% October 31.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 21Oct 8Oct 31
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 17 is the cautious spring date, with only a 10 % chance of a light frost later, and it lets a gardener plan to set out tender crops. By contrast, April 12 carries a 90 % chance of a frost and is a gamble for early planting. The 50 % spring date, April 30, marks the median point where a light frost is equally likely to have occurred or not, giving a sense of the central timing of frost risk.

September 21 is the cautious fall date, with just a 10 % chance that a light frost has arrived earlier, allowing a gardener to finish harvesting tender crops. The 50 % fall date, October 8, similarly represents an even-odds point for light frost. The hard-frost 50 % dates are April 6 and October 29; a hard frost at 28 °F can damage plant tissue 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 May 17" 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 Packwood, WANumbered nearest stations: 1 — Cougar, WA — 45 mi; 2 — Palmer, WA — 49 mi; 3 — near Carson, WA — 53 mi; 4 — Yakima, WA — 54 mi; 5 — near Wilderness Rim, WA — 56 mi.WA50 mi · 80 km1. Cougar, WA — 45 mi12. Palmer, WA — 49 mi23. near Carson, WA — 53 mi34. Yakima, WA — 54 mi45. near Wilderness Rim, WA — 56 mi5
  1. Cougar, WA 45 mi (73 km)
  2. Palmer, WA 49 mi (79 km)
  3. near Carson, WA 53 mi (86 km)
  4. Yakima, WA 54 mi (87 km)
  5. near Wilderness Rim, WA 56 mi (90 km)

Sources

* Hardiness zone 8a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 46.6092, -121.6744.