Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 98579 — Rochester, WA

ZIP code 98579 (Rochester, Thurston County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 22 and the first fall frost October 27.

Where ZIP 98579 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostApr 22

First frostOct 27

2012 zone8a

Was 8a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Rochester, WA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Rochester, WA

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 22median — 50% chance of a later frost

Safe for tender plantsMay 10only 10% chance of frost after

First fall frostOctober 27median — 10% chance by Oct 7

Growing season188 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 23 and returns around November 13.

From the NOAA station Centralia, WA — 9 miles away, elevation 184 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 98579

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 11 – Mar 25

SpinachSow outdoors · Mar 11 – Apr 1

Broccoli, cabbageStart indoors · Feb 11 – Feb 25

Broccoli, cabbageTransplant · Apr 1 – Apr 15

Onion setsPlant outdoors · Mar 25 – Apr 8

PotatoesPlant outdoors · Apr 1 – Apr 15

LettuceSow outdoors · Mar 25 – Apr 8

Carrots, beetsSow outdoors · Apr 1 – Apr 15

TomatoesStart indoors · Feb 25 – Mar 11

TomatoesTransplant · Apr 29 – May 13

Peppers, eggplantStart indoors · Feb 11 – Feb 25

Peppers, eggplantTransplant · May 6 – May 20

BeansSow outdoors · Apr 29 – May 13

Sweet cornSow outdoors · Apr 29 – May 13

Cucumbers, squashSow outdoors · Apr 29 – May 13

Fall lettuce, spinachSow outdoors · Sep 1 – Sep 15

GarlicPlant cloves · Oct 13 – Nov 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 22) and first fall frost (Oct 27) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 98579 came on Feb 28 — about the same time as the 1991–2020 average (Feb 26).

average
Feb 262026
Feb 28

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 8b in Washington

614 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Rochester, WA.

Soil in Rochester, WA

The soil mapped at the center of ZIP 98579 is Melbourne — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH6.1slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter5.5%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Melbourne silty clay loam, 20 to 40 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 98579; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rochester, WA

Summer high78 °Faverage high, July

Winter low34 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights48nights a year at 32 °F or less

Growing degree days1,943base 50 °F — the season’s usable heat

Longest day15 h 52 mindaylight on June 21

Shortest day8 h 32 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation41.6 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Centralia, WA (9 mi away); precipitation: Centralia, WA (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

985448b

Galvin, WA · 6 mi

985568a

Littlerock, WA · 7 mi

985688a

Oakville, WA · 10 mi

985318b

Centralia, WA · 11 mi

Washington planting zones →

Questions about 98579

What planting zone is ZIP code 98579?

ZIP code 98579 (Rochester, WA) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Rochester, WA?

The median last spring frost (32 °F) near 98579 is April 22; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Centralia station.

When is the first frost in Rochester, WA?

The median first fall frost near 98579 is October 27, giving a median frost-free growing season of 188 days.

When should I plant tomatoes in 98579?

Start tomato seeds indoors around Feb 25 – Mar 11 and set transplants outside around Apr 29 – May 13, one to three weeks after the median last frost.

How much rain and snow does 98579 get?

About 41.6 inches of precipitation a year (NOAA 1991–2020 normals, Centralia station).

How hot do summers get in Rochester, WA?

The average high peaks at 78 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 98579 have?

The USDA soil survey maps Melbourne at the center of ZIP 98579: silty clay loam, well drained, pH about 6.1 (slightly acidic).

Did spring come early in Rochester, WA in 2026?

Spring leaf-out near 98579 came on Feb 28 in 2026, about the same as the 1991–2020 average (Feb 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rochester, WA?

Long-day onions: the longest day near 98579 is 15 h 52 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 98579 change?

Yes. The 2012 USDA map put 98579 in zone 8a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.