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

Planting zone for 98849 — Riverside, WA

ZIP code 98849 (Riverside, Okanogan County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 30 and the first fall frost October 7.

Where ZIP 98849 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 30
First frostOct 7
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 Riverside, 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 Riverside, WA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 30median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 7median — 10% chance by Sep 23
Growing season160 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 14 and returns around October 19.

From the NOAA station Omak Airport, WA — 7 miles away, elevation 1,296 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 98849

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 19 – Apr 2
SpinachSow outdoors · Mar 19 – Apr 9
Broccoli, cabbageStart indoors · Feb 19 – Mar 5
Broccoli, cabbageTransplant · Apr 9 – Apr 23
Onion setsPlant outdoors · Apr 2 – Apr 16
PotatoesPlant outdoors · Apr 9 – Apr 23
LettuceSow outdoors · Apr 2 – Apr 16
Carrots, beetsSow outdoors · Apr 9 – Apr 23
TomatoesStart indoors · Mar 5 – Mar 19
TomatoesTransplant · May 7 – May 21
Peppers, eggplantStart indoors · Feb 19 – Mar 5
Peppers, eggplantTransplant · May 14 – May 28
BeansSow outdoors · May 7 – May 21
Sweet cornSow outdoors · May 7 – May 21
Cucumbers, squashSow outdoors · May 7 – May 21
Fall lettuce, spinachSow outdoors · Aug 12 – Aug 26
GarlicPlant cloves · Sep 23 – Oct 28
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 7) 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 98849 came on Apr 2 — 8 days earlier than the 1991–2020 average (Apr 10).

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.

Trees 31

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fbigleaf maple60 ft · blooms mid spring · medium shade tolerance · to −14 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °F

Shrubs 102

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FBarclay's willow15 ft · high shade tolerance · to −43 °F

Wildflowers & perennials 279

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 154

Alaska brome5 ft · blooms late spring · low shade tolerance · to −18 °FAlaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °F

Vines 3

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

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 Riverside, WA.

Soil in Riverside, WA

The soil mapped at the center of ZIP 98849 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-Conconully 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 98849; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Riverside, WA

Summer high89 °Faverage high, July
Winter low23 °Faverage low, January
Hot days42days a year at 90 °F or more
Freezing nights145nights a year at 32 °F or less
Growing degree days2,743base 50 °F — the season’s usable heat
Longest day16 h 08 mindaylight on June 21
Shortest day8 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation11.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 33 °F, low 23 °F 33°23° JanFebruary: average high 40 °F, low 25 °F 40°25° FebMarch: average high 53 °F, low 31 °F 53°31° MarApril: average high 63 °F, low 37 °F 63°37° AprMay: average high 72 °F, low 45 °F 72°45° MayJune: average high 79 °F, low 51 °F 79°51° JunJuly: average high 89 °F, low 58 °F 89°58° JulAugust: average high 89 °F, low 57 °F 89°57° AugSeptember: average high 78 °F, low 48 °F 78°48° SepOctober: average high 61 °F, low 38 °F 61°38° OctNovember: average high 43 °F, low 29 °F 43°29° NovDecember: average high 33 °F, low 23 °F 33°23° Dec

Precipitation by month inches

0″1″2″January: 1.33 in precipitation 1.3 JanFebruary: 0.91 in precipitation 0.9 FebMarch: 1.06 in precipitation 1.1 MarApril: 0.83 in precipitation 0.8 AprMay: 1.19 in precipitation 1.2 MayJune: 0.98 in precipitation 1.0 JunJuly: 0.52 in precipitation 0.5 JulAugust: 0.27 in precipitation 0.3 AugSeptember: 0.40 in precipitation 0.4 SepOctober: 0.92 in precipitation 0.9 OctNovember: 1.24 in precipitation 1.2 NovDecember: 1.95 in precipitation 1.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Omak Airport, WA (7 mi away); precipitation: Omak Airport, WA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

988556b
Tonasket, WA · 12 mi
988416b
Omak, WA · 12 mi
988407a
Okanogan, WA · 18 mi
988196b
Conconully, WA · 19 mi
991556b
Nespelem, WA · 24 mi
988296b
Malott, WA · 25 mi
988276a
Loomis, WA · 27 mi
988596a
Wauconda, WA · 27 mi

Washington planting zones →

Questions about 98849

What planting zone is ZIP code 98849?

ZIP code 98849 (Riverside, 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 Riverside, WA?

The median last spring frost (32 °F) near 98849 is April 30; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Omak Airport station.

When is the first frost in Riverside, WA?

The median first fall frost near 98849 is October 7, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 98849?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 98849 get?

About 11.6 inches of precipitation a year (NOAA 1991–2020 normals, Omak Airport station).

How hot do summers get in Riverside, WA?

The average high peaks at 89 °F in July, with about 42 days a year at 90 °F or more.

What kind of soil does 98849 have?

The USDA soil survey maps Lithic Haploxerepts at the center of ZIP 98849: cobbly ashy sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Riverside, WA in 2026?

Spring leaf-out near 98849 came on Apr 2 in 2026, 8 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Riverside, WA?

Long-day onions: the longest day near 98849 is 16 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).