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

Planting zone for 19399 — Southeastern, PA

ZIP code 19399 (Southeastern, Chester County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 19 and the first fall frost October 25.

Where ZIP 19399 is

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 19
First frostOct 25
2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Southeastern, PA…

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 Southeastern, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 19median — 50% chance of a later frost
Safe for tender plantsMay 4only 10% chance of frost after
First fall frostOctober 25median — 10% chance by Oct 11
Growing season190 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 3 and returns around November 6.

From the NOAA station Coatesville 2 W, PA — 6 miles away, elevation 640 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 19399

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 8 – Mar 22
SpinachSow outdoors · Mar 8 – Mar 29
Broccoli, cabbageStart indoors · Feb 8 – Feb 22
Broccoli, cabbageTransplant · Mar 29 – Apr 12
Onion setsPlant outdoors · Mar 22 – Apr 5
PotatoesPlant outdoors · Mar 29 – Apr 12
LettuceSow outdoors · Mar 22 – Apr 5
Carrots, beetsSow outdoors · Mar 29 – Apr 12
TomatoesStart indoors · Feb 22 – Mar 8
TomatoesTransplant · Apr 26 – May 10
Peppers, eggplantStart indoors · Feb 8 – Feb 22
Peppers, eggplantTransplant · May 3 – May 17
BeansSow outdoors · Apr 26 – May 10
Sweet cornSow outdoors · Apr 26 – May 10
Cucumbers, squashSow outdoors · Apr 26 – May 10
Fall lettuce, spinachSow outdoors · Aug 30 – Sep 13
GarlicPlant cloves · Oct 11 – Nov 15
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Oct 25) 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 19399 came on Mar 24 — 3 days earlier than the 1991–2020 average (Mar 27).

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 Pennsylvania

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

Trees 78

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 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 123

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °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 °F

Wildflowers & perennials 212

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 181

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °F

Vines 11

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms 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 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °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 Southeastern, PA.

Soil in Southeastern, PA

The soil mapped at the center of ZIP 19399 is Glenelg — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.4strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Glenelg silt loam, 3 to 8 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 19399; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Southeastern, PA

Summer high85 °Faverage high, July
Winter low22 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights120nights a year at 32 °F or less
Growing degree days3,302base 50 °F — the season’s usable heat
Longest day15 h 01 mindaylight on June 21
Shortest day9 h 20 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation49.5 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 42 °F, low 23 °F 42°23° FebMarch: average high 50 °F, low 31 °F 50°31° MarApril: average high 63 °F, low 40 °F 63°40° AprMay: average high 73 °F, low 50 °F 73°50° MayJune: average high 81 °F, low 59 °F 81°59° JunJuly: average high 85 °F, low 65 °F 85°65° JulAugust: average high 83 °F, low 63 °F 83°63° AugSeptember: average high 77 °F, low 56 °F 77°56° SepOctober: average high 65 °F, low 44 °F 65°44° OctNovember: average high 54 °F, low 34 °F 54°34° NovDecember: average high 43 °F, low 27 °F 43°27° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.59 in precipitation 3.6 JanFebruary: 3.09 in precipitation 3.1 FebMarch: 4.52 in precipitation 4.5 MarApril: 3.84 in precipitation 3.8 AprMay: 4.05 in precipitation 4.0 MayJune: 4.50 in precipitation 4.5 JunJuly: 4.60 in precipitation 4.6 JulAugust: 4.28 in precipitation 4.3 AugSeptember: 4.77 in precipitation 4.8 SepOctober: 4.58 in precipitation 4.6 OctNovember: 3.33 in precipitation 3.3 NovDecember: 4.30 in precipitation 4.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Coatesville 2 W, PA (6 mi away); precipitation: Unionville 2.2 Ne, PA (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

193767a
Wagontown, PA · <1 mi
193977a
Southeastern, PA · <1 mi
193987a
Southeastern, PA · <1 mi
194217a
Birchrunville, PA · <1 mi
193727a
Thorndale, PA · 1 mi
193357a
Downingtown, PA · 3 mi
193587a
Modena, PA · 3 mi
193207a
Coatesville, PA · 5 mi

All 3 ZIP codes in Southeastern → · Pennsylvania planting zones →

Questions about 19399

What planting zone is ZIP code 19399?

ZIP code 19399 (Southeastern, PA) 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 Southeastern, PA?

The median last spring frost (32 °F) near 19399 is April 19; after May 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Coatesville 2 W station.

When is the first frost in Southeastern, PA?

The median first fall frost near 19399 is October 25, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 19399?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 19399 get?

About 49.5 inches of precipitation a year (NOAA 1991–2020 normals, Unionville 2.2 Ne station).

How hot do summers get in Southeastern, PA?

The average high peaks at 85 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 19399 have?

The USDA soil survey maps Glenelg at the center of ZIP 19399: silt loam, well drained, pH about 5.4 (strongly acidic).

Did spring come early in Southeastern, PA in 2026?

Spring leaf-out near 19399 came on Mar 24 in 2026, 3 days earlier than the 1991–2020 average (Mar 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Southeastern, PA?

Long-day onions: the longest day near 19399 is 15 h 01 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).