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

Planting zone for 63670 — Sainte Genevieve, MO

ZIP code 63670 (Sainte Genevieve, Ste. Genevieve County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 8 and the first fall frost October 30.

Where ZIP 63670 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.

Zone6b−5 to 0 °F

Coldest night−20.6 to −17.8 °C

Last frostApr 8

First frostOct 30

2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Sainte Genevieve, 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 Sainte Genevieve, MO

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 8median — 50% chance of a later frost

Safe for tender plantsApril 25only 10% chance of frost after

First fall frostOctober 30median — 10% chance by Oct 15

Growing season202 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 28 and returns around November 10.

From the NOAA station Kaskaskia Rvr Navigation Lock, IL — 13 miles away, elevation 381 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 63670

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 25 – Mar 11

SpinachSow outdoors · Feb 25 – Mar 18

Broccoli, cabbageStart indoors · Jan 28 – Feb 11

Broccoli, cabbageTransplant · Mar 18 – Apr 1

Onion setsPlant outdoors · Mar 11 – Mar 25

PotatoesPlant outdoors · Mar 18 – Apr 1

LettuceSow outdoors · Mar 11 – Mar 25

Carrots, beetsSow outdoors · Mar 18 – Apr 1

TomatoesStart indoors · Feb 11 – Feb 25

TomatoesTransplant · Apr 15 – Apr 29

Peppers, eggplantStart indoors · Jan 28 – Feb 11

Peppers, eggplantTransplant · Apr 22 – May 6

BeansSow outdoors · Apr 15 – Apr 29

Sweet cornSow outdoors · Apr 15 – Apr 29

Cucumbers, squashSow outdoors · Apr 15 – Apr 29

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 8) 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 63670 came on Mar 2 — 9 days earlier than the 1991–2020 average (Mar 11).

average
Mar 112026
Mar 2

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 6b in Missouri

525 plants native to the lower 48 states, recorded in Missouri, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. 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 Sainte Genevieve, MO.

Soil in Sainte Genevieve, MO

The soil mapped at the center of ZIP 63670 is Wrengart — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables

pH5.6moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter2.2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Wrengart silt loam, 8 to 15 percent slopes, 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 63670; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sainte Genevieve, MO

Summer high89 °Faverage high, July

Winter low24 °Faverage low, January

Hot days58days a year at 90 °F or more

Freezing nights99nights a year at 32 °F or less

Growing degree days4,230base 50 °F — the season’s usable heat

Longest day14 h 48 mindaylight on June 21

Shortest day9 h 32 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation46.7 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: Kaskaskia Rvr Navigation Lock, IL (13 mi away); precipitation: Ste. Genevieve 10.4 Wsw, MO (2 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.

636736b

Saint Mary, MO · 10 mi

636276b

Bloomsdale, MO · 10 mi

622617a

Modoc, IL · 12 mi

630366b

French Village, MO · 12 mi

622777a

Prairie Du Rocher, IL · 14 mi

636406b

Farmington, MO · 15 mi

622797a

Renault, IL · 16 mi

622417a

Ellis Grove, IL · 16 mi

Missouri planting zones →

Questions about 63670

What planting zone is ZIP code 63670?

ZIP code 63670 (Sainte Genevieve, MO) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Sainte Genevieve, MO?

The median last spring frost (32 °F) near 63670 is April 8; after April 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Kaskaskia Rvr Navigation Lock station.

When is the first frost in Sainte Genevieve, MO?

The median first fall frost near 63670 is October 30, giving a median frost-free growing season of 202 days.

When should I plant tomatoes in 63670?

Start tomato seeds indoors around Feb 11 – Feb 25 and set transplants outside around Apr 15 – Apr 29, one to three weeks after the median last frost.

How much rain and snow does 63670 get?

About 46.7 inches of precipitation a year (NOAA 1991–2020 normals, Ste. Genevieve 10.4 Wsw station).

How hot do summers get in Sainte Genevieve, MO?

The average high peaks at 89 °F in July, with about 58 days a year at 90 °F or more.

What kind of soil does 63670 have?

The USDA soil survey maps Wrengart at the center of ZIP 63670: silt loam, moderately well drained, pH about 5.6 (moderately acidic).

Did spring come early in Sainte Genevieve, MO in 2026?

Spring leaf-out near 63670 came on Mar 2 in 2026, 9 days earlier than the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sainte Genevieve, MO?

Intermediate onions: the longest day near 63670 is 14 h 48 min, so day-neutral types bulb best; long-day varieties may not bulb fully.