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

Planting zone for 99330 — Eltopia, WA

ZIP code 99330 (Eltopia, Franklin County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 30 and the first fall frost October 13.

Where ZIP 99330 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 30
First frostOct 13
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 Eltopia, 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 Eltopia, 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 16only 10% chance of frost after
First fall frostOctober 13median — 10% chance by Sep 29
Growing season166 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 23.

From the NOAA station Sagemoor, WA — 7 miles away, elevation 594 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 99330

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 18 – Sep 1
GarlicPlant cloves · Sep 29 – Nov 3
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 13) 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 99330 came on Mar 9 — 5 days earlier than the 1991–2020 average (Mar 14).

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 Eltopia, WA.

Soil in Eltopia, WA

The soil mapped at the center of ZIP 99330 is Prosser — 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 matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Prosser silt loam, 2 to 5 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 99330; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Eltopia, WA

Summer high90 °Faverage high, July
Winter low25 °Faverage low, January
Hot days43days a year at 90 °F or more
Freezing nights127nights a year at 32 °F or less
Growing degree days2,773base 50 °F — the season’s usable heat
Longest day15 h 49 mindaylight on June 21
Shortest day8 h 34 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation9.8 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 41 °F, low 25 °F 41°25° JanFebruary: average high 48 °F, low 27 °F 48°27° FebMarch: average high 58 °F, low 32 °F 58°32° MarApril: average high 66 °F, low 36 °F 66°36° AprMay: average high 75 °F, low 44 °F 75°44° MayJune: average high 82 °F, low 50 °F 82°50° JunJuly: average high 90 °F, low 55 °F 90°55° JulAugust: average high 89 °F, low 54 °F 89°54° AugSeptember: average high 80 °F, low 47 °F 80°47° SepOctober: average high 66 °F, low 37 °F 66°37° OctNovember: average high 50 °F, low 29 °F 50°29° NovDecember: average high 40 °F, low 27 °F 40°27° Dec

Precipitation by month inches

0″1″2″January: 1.25 in precipitation 1.3 JanFebruary: 0.87 in precipitation 0.9 FebMarch: 1.04 in precipitation 1.0 MarApril: 0.78 in precipitation 0.8 AprMay: 0.83 in precipitation 0.8 MayJune: 0.76 in precipitation 0.8 JunJuly: 0.23 in precipitation 0.2 JulAugust: 0.27 in precipitation 0.3 AugSeptember: 0.34 in precipitation 0.3 SepOctober: 0.92 in precipitation 0.9 OctNovember: 1.08 in precipitation 1.1 NovDecember: 1.38 in precipitation 1.4 Dec

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

Nearby ZIP codes

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

993017a
Pasco, WA · 9 mi
993437a
Mesa, WA · 10 mi
993267a
Connell, WA · 15 mi
993547b
Richland, WA · 17 mi
993027b
Pasco, WA · 18 mi
993367b
Kennewick, WA · 21 mi
993537b
West Richland, WA · 21 mi
993527b
Richland, WA · 21 mi

Washington planting zones →

Questions about 99330

What planting zone is ZIP code 99330?

ZIP code 99330 (Eltopia, 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 Eltopia, WA?

The median last spring frost (32 °F) near 99330 is April 30; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sagemoor station.

When is the first frost in Eltopia, WA?

The median first fall frost near 99330 is October 13, giving a median frost-free growing season of 166 days.

When should I plant tomatoes in 99330?

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 99330 get?

About 9.8 inches of precipitation a year (NOAA 1991–2020 normals, Sagemoor station).

How hot do summers get in Eltopia, WA?

The average high peaks at 90 °F in July, with about 43 days a year at 90 °F or more.

What kind of soil does 99330 have?

The USDA soil survey maps Prosser at the center of ZIP 99330: silt loam, well drained, pH about 7.2 (neutral).

Did spring come early in Eltopia, WA in 2026?

Spring leaf-out near 99330 came on Mar 9 in 2026, 5 days earlier than the 1991–2020 average (Mar 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Eltopia, WA?

Long-day onions: the longest day near 99330 is 15 h 49 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).