Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 98837 — Moses Lake, WA

ZIP code 98837 (Moses Lake, Grant County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 27 and the first fall frost October 8.

Where ZIP 98837 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 27

First frostOct 8

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Moses Lake, 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 Moses Lake, WA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 27median — 50% chance of a later frost

Safe for tender plantsMay 11only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 29

Growing season165 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 10 and returns around October 20.

From the NOAA station Moses Lake Grant Co. Airport, WA — 4 miles away, elevation 1,198 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 98837

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 16 – Mar 30

SpinachSow outdoors · Mar 16 – Apr 6

Broccoli, cabbageStart indoors · Feb 16 – Mar 2

Broccoli, cabbageTransplant · Apr 6 – Apr 20

Onion setsPlant outdoors · Mar 30 – Apr 13

PotatoesPlant outdoors · Apr 6 – Apr 20

LettuceSow outdoors · Mar 30 – Apr 13

Carrots, beetsSow outdoors · Apr 6 – Apr 20

TomatoesStart indoors · Mar 2 – Mar 16

TomatoesTransplant · May 4 – May 18

Peppers, eggplantStart indoors · Feb 16 – Mar 2

Peppers, eggplantTransplant · May 11 – May 25

BeansSow outdoors · May 4 – May 18

Sweet cornSow outdoors · May 4 – May 18

Cucumbers, squashSow outdoors · May 4 – May 18

Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 8) 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 98837 came on Mar 21 — 4 days earlier than the 1991–2020 average (Mar 25).

average
Mar 252026
Mar 21

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.

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 Moses Lake, WA.

Soil in Moses Lake, WA

The soil mapped at the center of ZIP 98837 is Ephrata — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH7.6slightly alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Ephrata fine sandy loam, 0 to 2 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 98837; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Moses Lake, WA

Summer high90 °Faverage high, July

Winter low24 °Faverage low, January

Hot days43days a year at 90 °F or more

Freezing nights129nights a year at 32 °F or less

Growing degree days2,772base 50 °F — the season’s usable heat

Longest day15 h 55 mindaylight on June 21

Shortest day8 h 29 mindaylight on December 21

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

Precipitation7.8 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: Moses Lake Grant Co. Airport, WA (4 mi away); precipitation: Moses Lake Grant Co. Airport, WA (4 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.

Soap Lake, WA · 19 mi

988236b

Ephrata, WA · 20 mi

988536b

Stratford, WA · 22 mi

993447a

Othello, WA · 23 mi

988606b

Wilson Creek, WA · 24 mi

993577a

Royal City, WA · 24 mi

Washington planting zones →

Questions about 98837

What planting zone is ZIP code 98837?

ZIP code 98837 (Moses Lake, 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 Moses Lake, WA?

The median last spring frost (32 °F) near 98837 is April 27; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Moses Lake Grant Co. Airport station.

When is the first frost in Moses Lake, WA?

The median first fall frost near 98837 is October 8, giving a median frost-free growing season of 165 days.

When should I plant tomatoes in 98837?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 98837 get?

About 7.8 inches of precipitation a year (NOAA 1991–2020 normals, Moses Lake Grant Co. Airport station).

How hot do summers get in Moses Lake, 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 98837 have?

The USDA soil survey maps Ephrata at the center of ZIP 98837: fine sandy loam, well drained, pH about 7.6 (slightly alkaline).

Did spring come early in Moses Lake, WA in 2026?

Spring leaf-out near 98837 came on Mar 21 in 2026, 4 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Moses Lake, WA?

Long-day onions: the longest day near 98837 is 15 h 55 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 98837 change?

Yes. The 2012 USDA map put 98837 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.