U.S. Frost Dates by Weather Station

NOAA station USC00456295 · Washington

Frost Dates for Palmer, WA

NOAA weather station Palmer 3 ESE (USC00456295), Washington · elevation 920 ft (280 m) · hardiness zone 8b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 350% chance of a frost after it
  • Typical first fall frostNovember 1150% chance of a frost before it
  • Frost-free season219 daystypical year, 32°F
  • Hardiness zone8bcalculated*

The year at a glance

Frost season at Palmer, WASpring: a frost after March 7 in 9 years out of 10, after April 3 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 11 in half of the years, before December 3 in 9 years out of 10. Typical frost-free season: 219 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 3First frost ~Nov 11Frost season at Palmer, WASpring: a frost after March 7 in 9 years out of 10, after April 3 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 25 in 1 year out of 10, before November 11 in half of the years, before December 3 in 9 years out of 10. Typical frost-free season: 219 days.JFMAMJJASONDLast frost ~Apr 3First frost ~Nov 11
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 2October 25
50% (typical)April 3November 11
90% (likely)March 7December 3
Frost-free season (32°F, 50% chance)
219 days
Hard frost (28°F), last in spring, 50% chance after
February 28
Hard frost (28°F), first in fall, 50% chance before
December 1

The last 15 years (2006–2020 normals)

Typical last frost April 4 (1 day later than the 30-year normal), typical first fall frost November 12 (1 day later). Frost-free season 216 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 Palmer: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 26, 30% April 19, 40% April 11, 50% April 3, 60% March 30, 70% March 24, 80% March 17, 90% March 7. Observed last spring frost in recent years: 2021 April 13, 2023 April 14.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1May 2Apr 3Mar 72021: April 132023: April 14Fall at Palmer: chance of a frost before this dateFall, chance of a frost before the date: 10% October 25, 20% October 31, 30% November 4, 40% November 7, 50% November 11, 60% November 15, 70% November 21, 80% November 26, 90% December 3. Observed first fall frost in recent years: 2021 November 3, 2022 November 6, 2023 October 24.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 25Nov 11Dec 32021: November 32022: November 62023: October 24
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
2021April 13November 3
2022incomplete recordNovember 6
2023April 14October 24
2024incomplete recordincomplete record
2025no datano data
2026no dataseason not over yet

What these dates mean

Setting out tender crops on the early spring date, March 7, carries a 90% chance of a frost later than that date, making it a gamble for Palmer growers. The 50% date is April 3; it marks a 50% chance of a frost later than this date. In fall the 50% date is November 11, indicating a 50% chance of a frost earlier than this date.

For a more cautious approach, the spring cautious date is May 2, when only a 10% chance of a later frost remains, and the fall cautious date is October 25, when there is just a 10% chance that a frost has arrived earlier. Hard-frost thresholds are lower; a hard frost at 28 °F, with the 50% dates February 28 in spring and December 1 in fall, can damage plants that would survive 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 2" 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 October 25" 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 Palmer, WANumbered nearest stations: 1 — near Wilderness Rim, WA — 9 mi; 2 — Kent, WA — 20 mi; 3 — Seattle (Seattle-Tacoma Airport), WA — 24 mi; 4 — near Tacoma, WA — 27 mi; 5 — near Kirkland, WA — 32 mi.25 mi · 40 km1. near Wilderness Rim, WA — 9 mi12. Kent, WA — 20 mi23. Seattle (Seattle-Tacoma Airport), WA — 24 mi34. near Tacoma, WA — 27 mi45. near Kirkland, WA — 32 mi5
  1. near Wilderness Rim, WA 9 mi (14 km)
  2. Kent, WA 20 mi (32 km)
  3. Seattle (Seattle-Tacoma Airport), WA 24 mi (38 km)
  4. near Tacoma, WA 27 mi (43 km)
  5. near Kirkland, WA 32 mi (52 km)

Sources

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

Station coordinates: 47.3058, -121.8514.