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

Planting zone for 97456 — Monroe, OR

ZIP code 97456 (Monroe, Benton County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 11 and the first fall frost October 30.

Where ZIP 97456 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.

Zone8b15 to 20 °F
Coldest night−9.4 to −6.7 °C
Last frostApr 11
First frostOct 30
2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Monroe, 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 Monroe, OR

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 11median — 50% chance of a later frost
Safe for tender plantsMay 5only 10% chance of frost after
First fall frostOctober 30median — 10% chance by Oct 8
Growing season203 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 28 and returns around November 20.

From the NOAA station Corvallis 10 Ssw, OR — 6 miles away, elevation 312 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 97456

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 28 – Mar 14
SpinachSow outdoors · Feb 28 – Mar 21
Broccoli, cabbageStart indoors · Jan 31 – Feb 14
Broccoli, cabbageTransplant · Mar 21 – Apr 4
Onion setsPlant outdoors · Mar 14 – Mar 28
PotatoesPlant outdoors · Mar 21 – Apr 4
LettuceSow outdoors · Mar 14 – Mar 28
Carrots, beetsSow outdoors · Mar 21 – Apr 4
TomatoesStart indoors · Feb 14 – Feb 28
TomatoesTransplant · Apr 18 – May 2
Peppers, eggplantStart indoors · Jan 31 – Feb 14
Peppers, eggplantTransplant · Apr 25 – May 9
BeansSow outdoors · Apr 18 – May 2
Sweet cornSow outdoors · Apr 18 – May 2
Cucumbers, squashSow outdoors · Apr 18 – May 2
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 (Apr 11) 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 97456 came on Feb 27 — 6 days later than the 1991–2020 average (Feb 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 8b in Oregon

661 plants native to the lower 48 states, recorded in Oregon, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. Each links to its USDA PLANTS profile.

Trees 43

Alaska cedar75 ft · blooms mid spring · low shade tolerance · to −22 °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 °FBrewer spruce100 ft · blooms early summer · low shade tolerance · to −13 °F

Shrubs 132

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °Falpine laurel1 ft · blooms late spring · low shade tolerance · to −28 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 305

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 166

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 2

riverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Monroe, OR.

Soil in Monroe, OR

The soil mapped at the center of ZIP 97456 is McBee — silty clay loam, moderately well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter4.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: McBee silty clay loam, nonflooded, 0 to 3 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 97456; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Monroe, OR

Summer high82 °Faverage high, July
Winter low34 °Faverage low, January
Hot days15days a year at 90 °F or more
Freezing nights60nights a year at 32 °F or less
Growing degree days2,088base 50 °F — the season’s usable heat
Longest day15 h 32 mindaylight on June 21
Shortest day8 h 51 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation45.9 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°32 °FJanuary: average high 47 °F, low 34 °F 47°34° JanFebruary: average high 51 °F, low 35 °F 51°35° FebMarch: average high 55 °F, low 37 °F 55°37° MarApril: average high 60 °F, low 39 °F 60°39° AprMay: average high 67 °F, low 43 °F 67°43° MayJune: average high 73 °F, low 47 °F 73°47° JunJuly: average high 82 °F, low 51 °F 82°51° JulAugust: average high 82 °F, low 51 °F 82°51° AugSeptember: average high 77 °F, low 47 °F 77°47° SepOctober: average high 64 °F, low 42 °F 64°42° OctNovember: average high 52 °F, low 37 °F 52°37° NovDecember: average high 46 °F, low 34 °F 46°34° Dec

Precipitation by month inches

0″2″4″6″8″January: 6.88 in precipitation 6.9 JanFebruary: 5.57 in precipitation 5.6 FebMarch: 5.05 in precipitation 5.0 MarApril: 3.79 in precipitation 3.8 AprMay: 2.53 in precipitation 2.5 MayJune: 1.34 in precipitation 1.3 JunJuly: 0.36 in precipitation 0.4 JulAugust: 0.36 in precipitation 0.4 AugSeptember: 1.46 in precipitation 1.5 SepOctober: 3.67 in precipitation 3.7 OctNovember: 6.88 in precipitation 6.9 NovDecember: 8.05 in precipitation 8.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Corvallis 10 Ssw, OR (6 mi away); precipitation: Monroe 1.4 W, OR (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8b.

973338b
Corvallis, OR · 9 mi
974488b
Junction City, OR · 10 mi
974198b
Cheshire, OR · 12 mi
973488b
Halsey, OR · 12 mi
973248b
Alsea, OR · 13 mi
974128b
Blachly, OR · 14 mi
973778b
Shedd, OR · 15 mi
974098b
Alvadore, OR · 16 mi

Oregon planting zones →

Questions about 97456

What planting zone is ZIP code 97456?

ZIP code 97456 (Monroe, OR) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Monroe, OR?

The median last spring frost (32 °F) near 97456 is April 11; after May 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Corvallis 10 Ssw station.

When is the first frost in Monroe, OR?

The median first fall frost near 97456 is October 30, giving a median frost-free growing season of 203 days.

When should I plant tomatoes in 97456?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 97456 get?

About 45.9 inches of precipitation a year (NOAA 1991–2020 normals, Monroe 1.4 W station).

How hot do summers get in Monroe, OR?

The average high peaks at 82 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 97456 have?

The USDA soil survey maps McBee at the center of ZIP 97456: silty clay loam, moderately well drained, pH about 6.1 (slightly acidic).

Did spring come early in Monroe, OR in 2026?

Spring leaf-out near 97456 came on Feb 27 in 2026, 6 days later than the 1991–2020 average (Feb 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Monroe, OR?

Long-day onions: the longest day near 97456 is 15 h 32 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).