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

Planting zone for 98830 — Mansfield, WA

ZIP code 98830 (Mansfield, Douglas County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 26 and the first fall frost October 11.

Where ZIP 98830 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostApr 26

First frostOct 11

2012 zone6b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mansfield, 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 Mansfield, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 26median — 50% chance of a later frost

Safe for tender plantsMay 13only 10% chance of frost after

First fall frostOctober 11median — 10% chance by Sep 30

Growing season167 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 9 and returns around October 23.

From the NOAA station Chief Joseph Dam, WA — 9 miles away, elevation 833 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 98830

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 15 – Mar 29

SpinachSow outdoors · Mar 15 – Apr 5

Broccoli, cabbageStart indoors · Feb 15 – Mar 1

Broccoli, cabbageTransplant · Apr 5 – Apr 19

Onion setsPlant outdoors · Mar 29 – Apr 12

PotatoesPlant outdoors · Apr 5 – Apr 19

LettuceSow outdoors · Mar 29 – Apr 12

Carrots, beetsSow outdoors · Apr 5 – Apr 19

TomatoesStart indoors · Mar 1 – Mar 15

TomatoesTransplant · May 3 – May 17

Peppers, eggplantStart indoors · Feb 15 – Mar 1

Peppers, eggplantTransplant · May 10 – May 24

BeansSow outdoors · May 3 – May 17

Sweet cornSow outdoors · May 3 – May 17

Cucumbers, squashSow outdoors · May 3 – May 17

Fall lettuce, spinachSow outdoors · Aug 16 – Aug 30

GarlicPlant cloves · Sep 27 – Nov 1

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 26) and first fall frost (Oct 11) 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 98830 came on Mar 27 — 11 days earlier than the 1991–2020 average (Apr 7).

average
Apr 72026
Mar 27

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 6b in Washington

581 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Mansfield, WA.

Soil in Mansfield, WA

The soil mapped at the center of ZIP 98830 is Touhey — ashy fine sandy loam, well drained.

TextureAshy fine sandy loamdrains and warms fast; dries out and needs more feeding

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Touhey complex, 0 to 8 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 98830; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mansfield, WA

Summer high91 °Faverage high, July

Winter low23 °Faverage low, January

Hot days48days a year at 90 °F or more

Freezing nights128nights a year at 32 °F or less

Growing degree days2,942base 50 °F — the season’s usable heat

Longest day16 h 02 mindaylight on June 21

Shortest day8 h 23 mindaylight on December 21

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

Precipitation10.8 inper year, rain and melted snow

Snowfall28 inper year; 47 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

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

Nearby ZIP codes

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

988137a

Bridgeport, WA · 9 mi

991156b

Coulee City, WA · 16 mi

991337a

Grand Coulee, WA · 20 mi

988127a

Brewster, WA · 21 mi

988586b

Waterville, WA · 22 mi

988177b

Chelan Falls, WA · 22 mi

991237a

Electric City, WA · 22 mi

988467a

Pateros, WA · 22 mi

Washington planting zones →

Questions about 98830

What planting zone is ZIP code 98830?

ZIP code 98830 (Mansfield, WA) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Mansfield, WA?

The median last spring frost (32 °F) near 98830 is April 26; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Chief Joseph Dam station.

When is the first frost in Mansfield, WA?

The median first fall frost near 98830 is October 11, giving a median frost-free growing season of 167 days.

When should I plant tomatoes in 98830?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 98830 get?

About 10.8 inches of precipitation a year and 28 inches of snowfall (NOAA 1991–2020 normals, Chief Joseph Dam station).

How hot do summers get in Mansfield, WA?

The average high peaks at 91 °F in July, with about 48 days a year at 90 °F or more.

What kind of soil does 98830 have?

The USDA soil survey maps Touhey at the center of ZIP 98830: ashy fine sandy loam, well drained, pH about 6.7 (neutral).

Did spring come early in Mansfield, WA in 2026?

Spring leaf-out near 98830 came on Mar 27 in 2026, 11 days earlier than the 1991–2020 average (Apr 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mansfield, WA?

Long-day onions: the longest day near 98830 is 16 h 02 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).