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

Planting zone for 98844 — Oroville, WA

ZIP code 98844 (Oroville, Okanogan County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 6 and the first fall frost October 6.

Where ZIP 98844 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostMay 6

First frostOct 6

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Oroville, 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 Oroville, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 6median — 50% chance of a later frost

Safe for tender plantsMay 25only 10% chance of frost after

First fall frostOctober 6median — 10% chance by Sep 24

Growing season151 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 19 and returns around October 18.

From the NOAA station Tonasket 11ne, WA — 9 miles away, elevation 3,435 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 98844

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 25 – Apr 8

SpinachSow outdoors · Mar 25 – Apr 15

Broccoli, cabbageStart indoors · Feb 25 – Mar 11

Broccoli, cabbageTransplant · Apr 15 – Apr 29

Onion setsPlant outdoors · Apr 8 – Apr 22

PotatoesPlant outdoors · Apr 15 – Apr 29

LettuceSow outdoors · Apr 8 – Apr 22

Carrots, beetsSow outdoors · Apr 15 – Apr 29

TomatoesStart indoors · Mar 11 – Mar 25

TomatoesTransplant · May 13 – May 27

Peppers, eggplantStart indoors · Feb 25 – Mar 11

Peppers, eggplantTransplant · May 20 – Jun 3

BeansSow outdoors · May 13 – May 27

Sweet cornSow outdoors · May 13 – May 27

Cucumbers, squashSow outdoors · May 13 – May 27

Fall lettuce, spinachSow outdoors · Aug 11 – Aug 25

GarlicPlant cloves · Sep 22 – Oct 27

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 6) 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 98844 came on Apr 15 — 12 days earlier than the 1991–2020 average (Apr 27).

average
Apr 272026
Apr 15

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 6a in Washington

576 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 Oroville, WA.

Soil in Oroville, WA

The soil mapped at the center of ZIP 98844 is Lithic Haploxerepts — cobbly ashy sandy loam, well drained.

TextureCobbly ashy sandy loamdrains and warms fast; dries out and needs more feeding

pH7.0neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Lithic Haploxerepts-Molson complex, 15 to 45 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 98844; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oroville, WA

Summer high77 °Faverage high, July

Winter low16 °Faverage low, January

Hot days5days a year at 90 °F or more

Freezing nights173nights a year at 32 °F or less

Growing degree days1,454base 50 °F — the season’s usable heat

Longest day16 h 12 mindaylight on June 21

Shortest day8 h 14 mindaylight on December 21

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

Precipitation17.5 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: Tonasket 11ne, WA (9 mi away); precipitation: Tonasket 11ne, 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.

Riverside, WA · 28 mi

Washington planting zones →

Questions about 98844

What planting zone is ZIP code 98844?

ZIP code 98844 (Oroville, WA) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Oroville, WA?

The median last spring frost (32 °F) near 98844 is May 6; after May 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Tonasket 11ne station.

When is the first frost in Oroville, WA?

The median first fall frost near 98844 is October 6, giving a median frost-free growing season of 151 days.

When should I plant tomatoes in 98844?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 98844 get?

About 17.5 inches of precipitation a year (NOAA 1991–2020 normals, Tonasket 11ne station).

How hot do summers get in Oroville, WA?

The average high peaks at 77 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 98844 have?

The USDA soil survey maps Lithic Haploxerepts at the center of ZIP 98844: cobbly ashy sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Oroville, WA in 2026?

Spring leaf-out near 98844 came on Apr 15 in 2026, 12 days earlier than the 1991–2020 average (Apr 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Oroville, WA?

Long-day onions: the longest day near 98844 is 16 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 98844 change?

Yes. The 2012 USDA map put 98844 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.