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

Planting zone for 97862 — Milton Freewater, OR

ZIP code 97862 (Milton Freewater, Umatilla County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is March 25 and the first fall frost October 29.

Where ZIP 97862 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 frostMar 25
First frostOct 29
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 Milton Freewater, OR…

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 Milton Freewater, OR

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 25median — 50% chance of a later frost
Safe for tender plantsApril 16only 10% chance of frost after
First fall frostOctober 29median — 10% chance by Oct 12
Growing season218 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 5 and returns around November 11.

From the NOAA station Milton Freewater, OR — 5 miles away, elevation 971 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 97862

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 11 – Feb 25
SpinachSow outdoors · Feb 11 – Mar 4
Broccoli, cabbageStart indoors · Jan 14 – Jan 28
Broccoli, cabbageTransplant · Mar 4 – Mar 18
Onion setsPlant outdoors · Feb 25 – Mar 11
PotatoesPlant outdoors · Mar 4 – Mar 18
LettuceSow outdoors · Feb 25 – Mar 11
Carrots, beetsSow outdoors · Mar 4 – Mar 18
TomatoesStart indoors · Jan 28 – Feb 11
TomatoesTransplant · Apr 1 – Apr 15
Peppers, eggplantStart indoors · Jan 14 – Jan 28
Peppers, eggplantTransplant · Apr 8 – Apr 22
BeansSow outdoors · Apr 1 – Apr 15
Sweet cornSow outdoors · Apr 1 – Apr 15
Cucumbers, squashSow outdoors · Apr 1 – Apr 15
Fall lettuce, spinachSow outdoors · Sep 3 – Sep 17
GarlicPlant cloves · Oct 15 – Nov 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 25) and first fall frost (Oct 29) 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 97862 came on Mar 1 — 9 days earlier than the 1991–2020 average (Mar 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).

Soil in Milton Freewater, OR

The soil mapped at the center of ZIP 97862 is Palouse — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Palouse silt loam, 1 to 7 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 97862; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Milton Freewater, OR

Summer high90 °Faverage high, July
Winter low30 °Faverage low, January
Hot days39days a year at 90 °F or more
Freezing nights74nights a year at 32 °F or less
Growing degree days3,513base 50 °F — the season’s usable heat
Longest day15 h 45 mindaylight on June 21
Shortest day8 h 39 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation16.1 inper year, rain and melted snow
Snowfall7 inper year

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 44 °F, low 30 °F 44°30° JanFebruary: average high 49 °F, low 33 °F 49°33° FebMarch: average high 58 °F, low 39 °F 58°39° MarApril: average high 65 °F, low 44 °F 65°44° AprMay: average high 74 °F, low 50 °F 74°50° MayJune: average high 81 °F, low 56 °F 81°56° JunJuly: average high 90 °F, low 63 °F 90°63° JulAugust: average high 89 °F, low 62 °F 89°62° AugSeptember: average high 80 °F, low 55 °F 80°55° SepOctober: average high 66 °F, low 44 °F 66°44° OctNovember: average high 52 °F, low 36 °F 52°36° NovDecember: average high 44 °F, low 30 °F 44°30° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″January: 1.75 in precipitation, 2.4 in snowfall 1.8❄2 JanFebruary: 1.52 in precipitation, 1.3 in snowfall 1.5❄1 FebMarch: 1.70 in precipitation, 0.1 in snowfall 1.7 MarApril: 1.62 in precipitation 1.6 AprMay: 1.77 in precipitation 1.8 MayJune: 1.25 in precipitation 1.3 JunJuly: 0.34 in precipitation 0.3 JulAugust: 0.39 in precipitation 0.4 AugSeptember: 0.61 in precipitation 0.6 SepOctober: 1.22 in precipitation 1.2 OctNovember: 1.92 in precipitation, 0.3 in snowfall 1.9 NovDecember: 2.06 in precipitation, 3.1 in snowfall 2.1❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Milton Freewater, OR (5 mi away); precipitation: Milton Freewater, OR (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

978867a
Weston, OR · 9 mi
993247a
College Place, WA · 9 mi
978137a
Athena, OR · 11 mi
993627a
Walla Walla, WA · 12 mi
993297a
Dixie, WA · 17 mi
978107a
Adams, OR · 18 mi
993607a
Touchet, WA · 20 mi
993617a
Waitsburg, WA · 23 mi

Oregon planting zones →

Questions about 97862

What planting zone is ZIP code 97862?

ZIP code 97862 (Milton Freewater, OR) 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 Milton Freewater, OR?

The median last spring frost (32 °F) near 97862 is March 25; after April 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Milton Freewater station.

When is the first frost in Milton Freewater, OR?

The median first fall frost near 97862 is October 29, giving a median frost-free growing season of 218 days.

When should I plant tomatoes in 97862?

Start tomato seeds indoors around Jan 28 – Feb 11 and set transplants outside around Apr 1 – Apr 15, one to three weeks after the median last frost.

How much rain and snow does 97862 get?

About 16.1 inches of precipitation a year and 7 inches of snowfall (NOAA 1991–2020 normals, Milton Freewater station).

How hot do summers get in Milton Freewater, OR?

The average high peaks at 90 °F in July, with about 39 days a year at 90 °F or more.

What kind of soil does 97862 have?

The USDA soil survey maps Palouse at the center of ZIP 97862: silt loam, well drained, pH about 6.5 (neutral).

Did spring come early in Milton Freewater, OR in 2026?

Spring leaf-out near 97862 came on Mar 1 in 2026, 9 days earlier than the 1991–2020 average (Mar 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Milton Freewater, OR?

Long-day onions: the longest day near 97862 is 15 h 45 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).