U.S. Frost Dates by Weather Station

NOAA station USC00454169 · Washington

Frost Dates for Kent, WA

NOAA weather station Kent (USC00454169), Washington · elevation 30 ft (9 m) · hardiness zone 9a*

  • Lower-risk planting dateafter April 8only 1 spring in 10 still has a frost later
  • Typical last frostMarch 2050% chance of a frost after it
  • Typical first fall frostNovember 1050% chance of a frost before it
  • Frost-free season233 daystypical year, 32°F
  • Hardiness zone9acalculated*

The year at a glance

Frost season at Kent, WASpring: a frost after February 27 in 9 years out of 10, after March 20 in half of the years, after April 8 in 1 year out of 10. Fall: the first frost comes before October 26 in 1 year out of 10, before November 10 in half of the years, before November 26 in 9 years out of 10. Typical frost-free season: 233 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 20First frost ~Nov 10Frost season at Kent, WASpring: a frost after February 27 in 9 years out of 10, after March 20 in half of the years, after April 8 in 1 year out of 10. Fall: the first frost comes before October 26 in 1 year out of 10, before November 10 in half of the years, before November 26 in 9 years out of 10. Typical frost-free season: 233 days.JFMAMJJASONDLast frost ~Mar 20First frost ~Nov 10
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 8October 26
50% (typical)March 20November 10
90% (likely)February 27November 26
Frost-free season (32°F, 50% chance)
233 days
Hard frost (28°F), last in spring, 50% chance after
February 25
Hard frost (28°F), first in fall, 50% chance before
November 24

The last 15 years (2006–2020 normals)

Typical last frost March 23 (3 days later than the 30-year normal), typical first fall frost November 11 (1 day later). Frost-free season 233 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 Kent: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 8, 20% April 1, 30% March 29, 40% March 24, 50% March 20, 60% March 16, 70% March 12, 80% March 6, 90% February 27.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1Apr 8Mar 20Feb 27Fall at Kent: chance of a frost before this dateFall, chance of a frost before the date: 10% October 26, 20% October 31, 30% November 3, 40% November 7, 50% November 10, 60% November 13, 70% November 17, 80% November 22, 90% November 26.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 26Nov 10Nov 26
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

October 26 is the cautious fall date in Kent for finishing the harvest of tender crops. It carries only a 10 % chance that a light frost has arrived earlier, while November 26 would be a gamble with a 90 % chance of frost already occurring. In spring, April 8 serves as the cautious date for setting out tender crops, with a 10 % chance of a later frost; February 27 would be a gamble with a 90 % chance of frost later that season.

The 50 % light-frost dates are March 20 in spring and November 10 in fall; each represents the point where a gardener faces an even chance of a frost. The median hard-frost dates are February 25 and November 24, indicating the days on which a 28 °F frost is equally likely. A hard frost at 28 °F can damage plants that survive a light frost at 32 °F, making it a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after April 8" 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 26" 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 Kent, WANumbered nearest stations: 1 — Seattle (Seattle-Tacoma Airport), WA — 4 mi; 2 — near Tacoma, WA — 14 mi; 3 — near Kirkland, WA — 19 mi; 4 — Palmer, WA — 20 mi; 5 — near Wilderness Rim, WA — 23 mi.25 mi · 40 km1. Seattle (Seattle-Tacoma Airport), WA — 4 mi12. near Tacoma, WA — 14 mi23. near Kirkland, WA — 19 mi34. Palmer, WA — 20 mi45. near Wilderness Rim, WA — 23 mi5
  1. Seattle (Seattle-Tacoma Airport), WA 4 mi (6 km)
  2. near Tacoma, WA 14 mi (23 km)
  3. near Kirkland, WA 19 mi (30 km)
  4. Palmer, WA 20 mi (32 km)
  5. near Wilderness Rim, WA 23 mi (37 km)

Sources

* Hardiness zone 9a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 47.4172, -122.2433.