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

Planting zone for 99302 — Pasco, WA

ZIP code 99302 (Pasco, Franklin County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is March 28 and the first fall frost October 30.

Where ZIP 99302 is

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.

Zone7b5 to 10 °F

Coldest night−15 to −12.2 °C

Last frostMar 28

First frostOct 30

2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Pasco, 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 Pasco, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMarch 28median — 50% chance of a later frost

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

First fall frostOctober 30median — 10% chance by Oct 18

Growing season216 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 8 and returns around November 11.

From the NOAA station Kennewick, WA — 2 miles away, elevation 390 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 99302

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 14 – Feb 28

SpinachSow outdoors · Feb 14 – Mar 7

Broccoli, cabbageStart indoors · Jan 17 – Jan 31

Broccoli, cabbageTransplant · Mar 7 – Mar 21

Onion setsPlant outdoors · Feb 28 – Mar 14

PotatoesPlant outdoors · Mar 7 – Mar 21

LettuceSow outdoors · Feb 28 – Mar 14

Carrots, beetsSow outdoors · Mar 7 – Mar 21

TomatoesStart indoors · Jan 31 – Feb 14

TomatoesTransplant · Apr 4 – Apr 18

Peppers, eggplantStart indoors · Jan 17 – Jan 31

Peppers, eggplantTransplant · Apr 11 – Apr 25

BeansSow outdoors · Apr 4 – Apr 18

Sweet cornSow outdoors · Apr 4 – Apr 18

Cucumbers, squashSow outdoors · Apr 4 – Apr 18

Fall lettuce, spinachSow outdoors · Sep 4 – Sep 18

GarlicPlant cloves · Oct 16 – Nov 20

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 28) and first fall frost (Oct 30) 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 99302 came on Mar 3 — 5 days earlier than the 1991–2020 average (Mar 8).

average
Mar 82026
Mar 3

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 7b in Washington

592 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 7b. 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 Pasco, WA.

Soil in Pasco, WA

The soil mapped at the center of ZIP 99302 is Torripsamments — loamy fine sand, excessively drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding

pH7.5slightly alkaline; most vegetables like 6.0–7.0

DrainageExcessively drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Torripsamments complex, gently rolling.

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 99302; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Pasco, WA

Summer high91 °Faverage high, July

Winter low29 °Faverage low, January

Hot days48days a year at 90 °F or more

Freezing nights76nights a year at 32 °F or less

Growing degree days3,502base 50 °F — the season’s usable heat

Longest day15 h 47 mindaylight on June 21

Shortest day8 h 36 mindaylight on December 21

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

Precipitation7.9 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: Kennewick, WA (2 mi away); precipitation: Kennewick, WA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Kennewick, WA · 10 mi

Kennewick, WA · 13 mi

993537b

West Richland, WA · 15 mi

All 2 ZIP codes in Pasco → · Washington planting zones →

Questions about 99302

What planting zone is ZIP code 99302?

ZIP code 99302 (Pasco, WA) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Pasco, WA?

The median last spring frost (32 °F) near 99302 is March 28; after April 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Kennewick station.

When is the first frost in Pasco, WA?

The median first fall frost near 99302 is October 30, giving a median frost-free growing season of 216 days.

When should I plant tomatoes in 99302?

Start tomato seeds indoors around Jan 31 – Feb 14 and set transplants outside around Apr 4 – Apr 18, one to three weeks after the median last frost.

How much rain and snow does 99302 get?

About 7.9 inches of precipitation a year (NOAA 1991–2020 normals, Kennewick station).

How hot do summers get in Pasco, 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 99302 have?

The USDA soil survey maps Torripsamments at the center of ZIP 99302: loamy fine sand, excessively drained, pH about 7.5 (slightly alkaline).

Did spring come early in Pasco, WA in 2026?

Spring leaf-out near 99302 came on Mar 3 in 2026, 5 days earlier than the 1991–2020 average (Mar 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Pasco, WA?

Long-day onions: the longest day near 99302 is 15 h 47 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 99302 change?

Yes. The 2012 USDA map put 99302 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.