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

Planting zone for 64683 — Trenton, MO

ZIP code 64683 (Trenton, Grundy County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 16 and the first fall frost October 20.

Where ZIP 64683 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostApr 16

First frostOct 20

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Trenton, MO…

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 Trenton, MO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 16median — 50% chance of a later frost

Safe for tender plantsApril 29only 10% chance of frost after

First fall frostOctober 20median — 10% chance by Oct 5

Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 6 and returns around October 29.

From the NOAA station Trenton, MO — within 1 mile, elevation 837 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 64683

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 5 – Mar 19

SpinachSow outdoors · Mar 5 – Mar 26

Broccoli, cabbageStart indoors · Feb 5 – Feb 19

Broccoli, cabbageTransplant · Mar 26 – Apr 9

Onion setsPlant outdoors · Mar 19 – Apr 2

PotatoesPlant outdoors · Mar 26 – Apr 9

LettuceSow outdoors · Mar 19 – Apr 2

Carrots, beetsSow outdoors · Mar 26 – Apr 9

TomatoesStart indoors · Feb 19 – Mar 5

TomatoesTransplant · Apr 23 – May 7

Peppers, eggplantStart indoors · Feb 5 – Feb 19

Peppers, eggplantTransplant · Apr 30 – May 14

BeansSow outdoors · Apr 23 – May 7

Sweet cornSow outdoors · Apr 23 – May 7

Cucumbers, squashSow outdoors · Apr 23 – May 7

Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8

GarlicPlant cloves · Oct 6 – Nov 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 16) and first fall frost (Oct 20) 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 64683 came on Mar 8 — 17 days earlier than the 1991–2020 average (Mar 25).

average
Mar 252026
Mar 8

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 Trenton, MO

The soil mapped at the center of ZIP 64683 is Grundy — silty clay loam, somewhat poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH6.0slightly acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter3%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Grundy silty clay loam, 2 to 5 percent slopes, moderately eroded.

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 64683; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Trenton, MO

Summer high89 °Faverage high, July

Winter low16 °Faverage low, January

Hot days41days a year at 90 °F or more

Freezing nights127nights a year at 32 °F or less

Growing degree days3,765base 50 °F — the season’s usable heat

Longest day15 h 01 mindaylight on June 21

Shortest day9 h 19 mindaylight on December 21

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

Precipitation40.1 inper year, rain and melted snow

Snowfall17 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Trenton, MO (within 1 mile); precipitation: Trenton, MO (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Jamesport, MO · 11 mi

Gilman City, MO · 14 mi

646466a

Humphreys, MO · 16 mi

646546a

Lock Springs, MO · 18 mi

Missouri planting zones →

Questions about 64683

What planting zone is ZIP code 64683?

ZIP code 64683 (Trenton, MO) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Trenton, MO?

The median last spring frost (32 °F) near 64683 is April 16; after April 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Trenton station.

When is the first frost in Trenton, MO?

The median first fall frost near 64683 is October 20, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 64683?

Start tomato seeds indoors around Feb 19 – Mar 5 and set transplants outside around Apr 23 – May 7, one to three weeks after the median last frost.

How much rain and snow does 64683 get?

About 40.1 inches of precipitation a year and 17 inches of snowfall (NOAA 1991–2020 normals, Trenton station).

How hot do summers get in Trenton, MO?

The average high peaks at 89 °F in July, with about 41 days a year at 90 °F or more.

What kind of soil does 64683 have?

The USDA soil survey maps Grundy at the center of ZIP 64683: silty clay loam, somewhat poorly drained, pH about 6.0 (slightly acidic).

Did spring come early in Trenton, MO in 2026?

Spring leaf-out near 64683 came on Mar 8 in 2026, 17 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Trenton, MO?

Long-day onions: the longest day near 64683 is 15 h 01 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 64683 change?

Yes. The 2012 USDA map put 64683 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.