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

Planting zone for 99335 — Kahlotus, WA

ZIP code 99335 (Kahlotus, Franklin County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 25 and the first fall frost October 15.

Where ZIP 99335 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 25
First frostOct 15
2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Kahlotus, 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 Kahlotus, WA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 25median — 50% chance of a later frost
Safe for tender plantsMay 11only 10% chance of frost after
First fall frostOctober 15median — 10% chance by Oct 2
Growing season173 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around October 28.

From the NOAA station Hatton 9 Se, WA — 11 miles away, elevation 1,506 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 99335

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 14 – Mar 28
SpinachSow outdoors · Mar 14 – Apr 4
Broccoli, cabbageStart indoors · Feb 14 – Feb 28
Broccoli, cabbageTransplant · Apr 4 – Apr 18
Onion setsPlant outdoors · Mar 28 – Apr 11
PotatoesPlant outdoors · Apr 4 – Apr 18
LettuceSow outdoors · Mar 28 – Apr 11
Carrots, beetsSow outdoors · Apr 4 – Apr 18
TomatoesStart indoors · Feb 28 – Mar 14
TomatoesTransplant · May 2 – May 16
Peppers, eggplantStart indoors · Feb 14 – Feb 28
Peppers, eggplantTransplant · May 9 – May 23
BeansSow outdoors · May 2 – May 16
Sweet cornSow outdoors · May 2 – May 16
Cucumbers, squashSow outdoors · May 2 – May 16
Fall lettuce, spinachSow outdoors · Aug 20 – Sep 3
GarlicPlant cloves · Oct 1 – Nov 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 25) and first fall frost (Oct 15) 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 99335 came on Mar 6 — 9 days earlier than the 1991–2020 average (Mar 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 7a in Washington

590 plants native to the lower 48 states, recorded in Washington, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 105

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 282

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 157

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 Kahlotus, WA.

Soil in Kahlotus, WA

The soil mapped at the center of ZIP 99335 is Ritzville — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Ritzville silt loam, 30 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 99335; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Kahlotus, WA

Summer high90 °Faverage high, July
Winter low26 °Faverage low, December
Hot days38days a year at 90 °F or more
Freezing nights103nights a year at 32 °F or less
Growing degree days2,840base 50 °F — the season’s usable heat
Longest day15 h 51 mindaylight on June 21
Shortest day8 h 33 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
Snowfall14 inper year; 19 days with snow on the ground

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 39 °F, low 27 °F 39°27° JanFebruary: average high 45 °F, low 29 °F 45°29° FebMarch: average high 55 °F, low 34 °F 55°34° MarApril: average high 63 °F, low 38 °F 63°38° AprMay: average high 73 °F, low 45 °F 73°45° MayJune: average high 80 °F, low 51 °F 80°51° JunJuly: average high 90 °F, low 58 °F 90°58° JulAugust: average high 88 °F, low 57 °F 88°57° AugSeptember: average high 79 °F, low 50 °F 79°50° SepOctober: average high 63 °F, low 40 °F 63°40° OctNovember: average high 47 °F, low 32 °F 47°32° NovDecember: average high 38 °F, low 26 °F 38°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 1.24 in precipitation, 4 in snowfall 1.2❄4 JanFebruary: 0.90 in precipitation, 2.5 in snowfall 0.9❄3 FebMarch: 1.27 in precipitation, 0.7 in snowfall 1.3❄1 MarApril: 1.05 in precipitation, 0.1 in snowfall 1.1 AprMay: 0.93 in precipitation 0.9 MayJune: 0.79 in precipitation 0.8 JunJuly: 0.23 in precipitation 0.2 JulAugust: 0.26 in precipitation 0.3 AugSeptember: 0.39 in precipitation 0.4 SepOctober: 1.01 in precipitation 1.0 OctNovember: 1.41 in precipitation, 1.4 in snowfall 1.4❄1 NovDecember: 1.36 in precipitation, 4.8 in snowfall 1.4❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hatton 9 Se, WA (11 mi away); precipitation: Hatton 9 Se, WA (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

993717a
Washtucna, WA · 11 mi
993337a
Hooper, WA · 15 mi
993597b
Starbuck, WA · 16 mi
993487a
Prescott, WA · 17 mi
993267a
Connell, WA · 19 mi
993417a
Lind, WA · 20 mi
991367a
Hay, WA · 23 mi
991057a
Benge, WA · 28 mi

Washington planting zones →

Questions about 99335

What planting zone is ZIP code 99335?

ZIP code 99335 (Kahlotus, WA) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Kahlotus, WA?

The median last spring frost (32 °F) near 99335 is April 25; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hatton 9 Se station.

When is the first frost in Kahlotus, WA?

The median first fall frost near 99335 is October 15, giving a median frost-free growing season of 173 days.

When should I plant tomatoes in 99335?

Start tomato seeds indoors around Feb 28 – Mar 14 and set transplants outside around May 2 – May 16, one to three weeks after the median last frost.

How much rain and snow does 99335 get?

About 10.8 inches of precipitation a year and 14 inches of snowfall (NOAA 1991–2020 normals, Hatton 9 Se station).

How hot do summers get in Kahlotus, WA?

The average high peaks at 90 °F in July, with about 38 days a year at 90 °F or more.

What kind of soil does 99335 have?

The USDA soil survey maps Ritzville at the center of ZIP 99335: silt loam, well drained, pH about 7.2 (neutral).

Did spring come early in Kahlotus, WA in 2026?

Spring leaf-out near 99335 came on Mar 6 in 2026, 9 days earlier than the 1991–2020 average (Mar 15), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Kahlotus, WA?

Long-day onions: the longest day near 99335 is 15 h 51 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).