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

Planting zone for 63138 — Saint Louis, MO

ZIP code 63138 (Saint Louis, St. Louis County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 4 and the first fall frost November 5.

Where ZIP 63138 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 4
First frostNov 5
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 Saint Louis, 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 Saint Louis, MO

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 4median — 50% chance of a later frost
Safe for tender plantsApril 19only 10% chance of frost after
First fall frostNovember 5median — 10% chance by Oct 25
Growing season214 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 25 and returns around November 16.

From the NOAA station Alton - Melvin Price L&D, IL — 5 miles away, elevation 404 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 63138

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 21 – Mar 7
SpinachSow outdoors · Feb 21 – Mar 14
Broccoli, cabbageStart indoors · Jan 24 – Feb 7
Broccoli, cabbageTransplant · Mar 14 – Mar 28
Onion setsPlant outdoors · Mar 7 – Mar 21
PotatoesPlant outdoors · Mar 14 – Mar 28
LettuceSow outdoors · Mar 7 – Mar 21
Carrots, beetsSow outdoors · Mar 14 – Mar 28
TomatoesStart indoors · Feb 7 – Feb 21
TomatoesTransplant · Apr 11 – Apr 25
Peppers, eggplantStart indoors · Jan 24 – Feb 7
Peppers, eggplantTransplant · Apr 18 – May 2
BeansSow outdoors · Apr 11 – Apr 25
Sweet cornSow outdoors · Apr 11 – Apr 25
Cucumbers, squashSow outdoors · Apr 11 – Apr 25
Fall lettuce, spinachSow outdoors · Sep 10 – Sep 24
GarlicPlant cloves · Oct 22 – Nov 26
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 4) and first fall frost (Nov 5) 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 63138 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 Saint Louis, MO.

Soil in Saint Louis, MO

The center of ZIP 63138 is mapped as Water: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 63138; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Saint Louis, MO

Summer high87 °Faverage high, July
Winter low22 °Faverage low, January
Hot days29days a year at 90 °F or more
Freezing nights85nights a year at 32 °F or less
Growing degree days4,168base 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
Precipitation41.9 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 39 °F, low 22 °F 39°22° JanFebruary: average high 44 °F, low 25 °F 44°25° FebMarch: average high 54 °F, low 35 °F 54°35° MarApril: average high 66 °F, low 45 °F 66°45° AprMay: average high 75 °F, low 56 °F 75°56° MayJune: average high 84 °F, low 66 °F 84°66° JunJuly: average high 87 °F, low 69 °F 87°69° JulAugust: average high 86 °F, low 67 °F 86°67° AugSeptember: average high 80 °F, low 60 °F 80°60° SepOctober: average high 68 °F, low 48 °F 68°48° OctNovember: average high 54 °F, low 37 °F 54°37° NovDecember: average high 44 °F, low 27 °F 44°27° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 2.53 in precipitation 2.5 JanFebruary: 2.52 in precipitation 2.5 FebMarch: 3.46 in precipitation 3.5 MarApril: 4.92 in precipitation 4.9 AprMay: 5.46 in precipitation 5.5 MayJune: 3.40 in precipitation 3.4 JunJuly: 3.95 in precipitation 4.0 JulAugust: 3.30 in precipitation 3.3 AugSeptember: 3.38 in precipitation 3.4 SepOctober: 2.93 in precipitation 2.9 OctNovember: 3.43 in precipitation 3.4 NovDecember: 2.59 in precipitation 2.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Alton - Melvin Price L&D, IL (5 mi away); precipitation: Alton - Melvin Price L&D, IL (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

620487a
Hartford, IL · 4 mi
631377a
Saint Louis, MO · 4 mi
630337a
Florissant, MO · 4 mi
633867a
West Alton, MO · 5 mi
631367a
Saint Louis, MO · 5 mi
630347a
Florissant, MO · 6 mi
620877a
South Roxana, IL · 7 mi
631357a
Saint Louis, MO · 7 mi

All 66 ZIP codes in Saint Louis → · Missouri planting zones →

Questions about 63138

What planting zone is ZIP code 63138?

ZIP code 63138 (Saint Louis, 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 Saint Louis, MO?

The median last spring frost (32 °F) near 63138 is April 4; after April 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alton - Melvin Price L&D station.

When is the first frost in Saint Louis, MO?

The median first fall frost near 63138 is November 5, giving a median frost-free growing season of 214 days.

When should I plant tomatoes in 63138?

Start tomato seeds indoors around Feb 7 – Feb 21 and set transplants outside around Apr 11 – Apr 25, one to three weeks after the median last frost.

How much rain and snow does 63138 get?

About 41.9 inches of precipitation a year (NOAA 1991–2020 normals, Alton - Melvin Price L&D station).

How hot do summers get in Saint Louis, MO?

The average high peaks at 87 °F in July, with about 29 days a year at 90 °F or more.

Did spring come early in Saint Louis, MO in 2026?

Spring leaf-out near 63138 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 Saint Louis, MO?

Intermediate onions: the longest day near 63138 is 14 h 53 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 63138 change?

Yes. The 2012 USDA map put 63138 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.