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

Planting zone for 63031 — Florissant, MO

ZIP code 63031 (Florissant, St. Louis County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 2 and the first fall frost November 4.

Where ZIP 63031 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 2
First frostNov 4
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 Florissant, 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 Florissant, MO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 2median — 50% chance of a later frost
Safe for tender plantsApril 17only 10% chance of frost after
First fall frostNovember 4median — 10% chance by Oct 23
Growing season215 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 23 and returns around November 13.

From the NOAA station St Louis Lambert Intl Airport, MO — 4 miles away, elevation 532 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 63031

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 19 – Mar 5
SpinachSow outdoors · Feb 19 – Mar 12
Broccoli, cabbageStart indoors · Jan 22 – Feb 5
Broccoli, cabbageTransplant · Mar 12 – Mar 26
Onion setsPlant outdoors · Mar 5 – Mar 19
PotatoesPlant outdoors · Mar 12 – Mar 26
LettuceSow outdoors · Mar 5 – Mar 19
Carrots, beetsSow outdoors · Mar 12 – Mar 26
TomatoesStart indoors · Feb 5 – Feb 19
TomatoesTransplant · Apr 9 – Apr 23
Peppers, eggplantStart indoors · Jan 22 – Feb 5
Peppers, eggplantTransplant · Apr 16 – Apr 30
BeansSow outdoors · Apr 9 – Apr 23
Sweet cornSow outdoors · Apr 9 – Apr 23
Cucumbers, squashSow outdoors · Apr 9 – Apr 23
Fall lettuce, spinachSow outdoors · Sep 9 – Sep 23
GarlicPlant cloves · Oct 21 – Nov 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 2) and first fall frost (Nov 4) 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 63031 came on Mar 3 — 11 days earlier than the 1991–2020 average (Mar 14).

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 Missouri

540 plants native to the lower 48 states, recorded in Missouri, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 72

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbald cypress130 ft · blooms mid spring · medium shade tolerance · to −18 °F

Shrubs 85

alternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 195

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 163

alkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fblister sedge3 ft · blooms late spring · medium shade tolerance · to −38 °F

Vines 14

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °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 Florissant, MO.

Soil in Florissant, MO

The soil mapped at the center of ZIP 63031 is Nevin — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter3.5%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Nevin-Urban land complex, 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 63031; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Florissant, MO

Summer high90 °Faverage high, July
Winter low24 °Faverage low, January
Hot days47days a year at 90 °F or more
Freezing nights85nights a year at 32 °F or less
Growing degree days4,590base 50 °F — the season’s usable heat
Longest day14 h 53 mindaylight on June 21
Shortest day9 h 27 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation43.6 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 40 °F, low 24 °F 40°24° JanFebruary: average high 46 °F, low 28 °F 46°28° FebMarch: average high 57 °F, low 37 °F 57°37° MarApril: average high 68 °F, low 47 °F 68°47° AprMay: average high 77 °F, low 58 °F 77°58° MayJune: average high 86 °F, low 67 °F 86°67° JunJuly: average high 90 °F, low 71 °F 90°71° JulAugust: average high 88 °F, low 69 °F 88°69° AugSeptember: average high 81 °F, low 61 °F 81°61° SepOctober: average high 69 °F, low 49 °F 69°49° OctNovember: average high 56 °F, low 37 °F 56°37° NovDecember: average high 45 °F, low 29 °F 45°29° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 2.66 in precipitation 2.7 JanFebruary: 2.33 in precipitation 2.3 FebMarch: 3.54 in precipitation 3.5 MarApril: 4.83 in precipitation 4.8 AprMay: 5.14 in precipitation 5.1 MayJune: 4.72 in precipitation 4.7 JunJuly: 3.93 in precipitation 3.9 JulAugust: 3.77 in precipitation 3.8 AugSeptember: 3.17 in precipitation 3.2 SepOctober: 3.29 in precipitation 3.3 OctNovember: 3.51 in precipitation 3.5 NovDecember: 2.70 in precipitation 2.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: St Louis Lambert Intl Airport, MO (4 mi away); precipitation: Florissant 2.9 W, MO (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

630427a
Hazelwood, MO · 3 mi
630347a
Florissant, MO · 4 mi
630337a
Florissant, MO · 4 mi
630446b
Bridgeton, MO · 5 mi
631347a
Saint Louis, MO · 5 mi
631357a
Saint Louis, MO · 5 mi
631407a
Saint Louis, MO · 5 mi
630747a
Saint Ann, MO · 6 mi

All 4 ZIP codes in Florissant → · Missouri planting zones →

Questions about 63031

What planting zone is ZIP code 63031?

ZIP code 63031 (Florissant, MO) 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 Florissant, MO?

The median last spring frost (32 °F) near 63031 is April 2; after April 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, St Louis Lambert Intl Airport station.

When is the first frost in Florissant, MO?

The median first fall frost near 63031 is November 4, giving a median frost-free growing season of 215 days.

When should I plant tomatoes in 63031?

Start tomato seeds indoors around Feb 5 – Feb 19 and set transplants outside around Apr 9 – Apr 23, one to three weeks after the median last frost.

How much rain and snow does 63031 get?

About 43.6 inches of precipitation a year (NOAA 1991–2020 normals, Florissant 2.9 W station).

How hot do summers get in Florissant, MO?

The average high peaks at 90 °F in July, with about 47 days a year at 90 °F or more.

What kind of soil does 63031 have?

The USDA soil survey maps Nevin at the center of ZIP 63031: silt loam, somewhat poorly drained, pH about 6.5 (neutral).

Did spring come early in Florissant, MO in 2026?

Spring leaf-out near 63031 came on Mar 3 in 2026, 11 days earlier than the 1991–2020 average (Mar 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Florissant, MO?

Intermediate onions: the longest day near 63031 is 14 h 53 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 63031 change?

Yes. The 2012 USDA map put 63031 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.