When is the last frost in Renton, WA?

The average last spring frost (50% probability of 32°F) in Renton is around March 13, based on NOAA/NCEI 1991–2020 normals at the Renton Muni Ap, WA station (1.5 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Renton?

The average first fall frost in Renton, WA is around November 16, giving roughly a 248-day frost-free growing season.

What planting zone is Renton, WA?

Renton is in USDA plant hardiness zone 9a (average annual extreme minimum temperature 20 to 25°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Renton?

In Renton, WA the warmest month is August (avg high 77.6°F) and the coldest is December (avg low 37.1°F). It averages about 39.3″ of precipitation a year and 6.3″ of snow.

Home › Washington › Renton

Renton, WA Planting Calendar & Frost Dates

USDA hardiness zone 9a · ZIP 98057 · elevation 113′ · NOAA & USDA data

Renton is in USDA hardiness zone 9a (winters can dip to 20 to 25°F), with a growing season of about 248 days between the average last spring frost (March 13) and first fall frost (November 16). The warmest month is August (avg high 77.6°F); the coldest is December (avg low 37.1°F). It averages 39.3″ of precipitation a year and 6.3″ of snow, mostly mid-winter. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 20 to 25°F

Last spring frost

March 13

avg (50% prob, 32°F)

First fall frost

November 16

avg (50% prob, 32°F)

Growing season

248 days

frost-free window

Warmest month

August

avg high 77.6°F

Month-by-month typical weather in Renton

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Seattle Tacoma Intl Ap, WA (4.8 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	48	37.7	42.8	5.8	1.8
February	50.3	37.7	44	3.8	2.2
March	54.2	39.9	47.1	4.2	0.4
April	59.3	43.3	51.3	3.2	0
May	66.3	48.7	57.5	1.9	0
June	71.1	53	62	1.5	0
July	77.4	56.8	67.1	0.6	0
August	77.6	57.2	67.4	1	0
September	71.6	53.6	62.6	1.6	0
October	60.5	47	53.8	3.9	0
November	52.1	40.9	46.5	6.3	0.2
December	47	37.1	42	5.7	1.7

What to plant when in Renton

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: January 30 · Transplant out: March 20
Peppers	warm	Start seeds indoors: January 16 · Transplant out: March 27
Cucumbers	warm	Direct sow: March 20
Zucchini / squash	warm	Direct sow: March 20
Bush beans	warm	Direct sow: March 20
Sweet corn	warm	Direct sow: March 20
Basil	warm	Transplant out: March 20
Peas	cool	Sow (spring): February 6 · Sow (fall): September 21
Spinach	cool	Sow (spring): January 30 · Sow (fall): September 21
Lettuce	cool	Sow (spring): February 13 · Sow (fall): September 21
Kale	cool	Transplant (spring): February 20 · Sow (fall): September 7
Broccoli	cool	Transplant (spring): February 27
Carrots	cool	Sow (spring): February 20 · Sow (fall): September 7
Onions	cool	Transplant (spring): February 13
Potatoes	cool	Plant seed potatoes: February 27
Radishes	cool	Sow (spring): February 13 · Sow (fall): October 5

Dates are computed from Renton's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

Want the exact dates for your yard? →
Look up your precise ZIP-code frost dates and a full 26-crop planting calendar on our free interactive tool.
Open the frost & planting tool

🌾 Get a frost reminder

One email in early spring and early fall with the dates for your area. No spam.

Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Washington

Kent, WA Seattle, WA Bellevue, WA Auburn, WA Sammamish, WA Federal Way, WA Kirkland, WA Redmond, WA

Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Renton Muni Ap, WA, 1.5 mi (confidence: high). Monthly weather normals: Seattle Tacoma Intl Ap, WA, 4.8 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.