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

Planting zone for 19898 — Wilmington, DE

ZIP code 19898 (Wilmington, New Castle County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 7 and the first fall frost November 4.

Where ZIP 19898 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.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostApr 7
First frostNov 4
2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Wilmington, DE…

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 Wilmington, DE

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 7median — 50% chance of a later frost
Safe for tender plantsApril 24only 10% chance of frost after
First fall frostNovember 4median — 10% chance by Oct 21
Growing season209 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 15.

From the NOAA station Wilmington Porter Rsch, DE — 2 miles away, elevation 269 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 19898

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 24 – Mar 10
SpinachSow outdoors · Feb 24 – Mar 17
Broccoli, cabbageStart indoors · Jan 27 – Feb 10
Broccoli, cabbageTransplant · Mar 17 – Mar 31
Onion setsPlant outdoors · Mar 10 – Mar 24
PotatoesPlant outdoors · Mar 17 – Mar 31
LettuceSow outdoors · Mar 10 – Mar 24
Carrots, beetsSow outdoors · Mar 17 – Mar 31
TomatoesStart indoors · Feb 10 – Feb 24
TomatoesTransplant · Apr 14 – Apr 28
Peppers, eggplantStart indoors · Jan 27 – Feb 10
Peppers, eggplantTransplant · Apr 21 – May 5
BeansSow outdoors · Apr 14 – Apr 28
Sweet cornSow outdoors · Apr 14 – Apr 28
Cucumbers, squashSow outdoors · Apr 14 – Apr 28
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 7) 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 19898 came on Mar 15 — 4 days earlier than the 1991–2020 average (Mar 19).

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 7b in Delaware

503 plants native to the lower 48 states, recorded in Delaware, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. Each links to its USDA PLANTS profile.

Trees 65

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 °FAtlantic white cedar50 ft · blooms spring · medium shade tolerance · to −36 °F

Shrubs 103

Allegheny 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 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 170

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 143

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °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 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °F

Vines 10

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 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °Fmuscadine30 ft · blooms late spring · medium shade tolerance · to −18 °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 Wilmington, DE.

Soil in Wilmington, DE

The soil mapped at the center of ZIP 19898 is Udorthents — silt loam. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSilt loama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
Organic matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land, bedrock substratum.

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 19898; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Wilmington, DE

Summer high84 °Faverage high, July
Winter low24 °Faverage low, January
Hot days17days a year at 90 °F or more
Freezing nights87nights a year at 32 °F or less
Growing degree days3,419base 50 °F — the season’s usable heat
Longest day14 h 59 mindaylight on June 21
Shortest day9 h 21 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation50.3 inper year, rain and melted snow
Snowfall12 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 38 °F, low 24 °F 38°24° JanFebruary: average high 41 °F, low 25 °F 41°25° FebMarch: average high 49 °F, low 32 °F 49°32° MarApril: average high 61 °F, low 43 °F 61°43° AprMay: average high 71 °F, low 52 °F 71°52° MayJune: average high 79 °F, low 62 °F 79°62° JunJuly: average high 84 °F, low 67 °F 84°67° JulAugust: average high 82 °F, low 66 °F 82°66° AugSeptember: average high 75 °F, low 59 °F 75°59° SepOctober: average high 63 °F, low 47 °F 63°47° OctNovember: average high 53 °F, low 37 °F 53°37° NovDecember: average high 43 °F, low 29 °F 43°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.67 in precipitation, 5.3 in snowfall 3.7❄5 JanFebruary: 3.03 in precipitation, 4 in snowfall 3.0❄4 FebMarch: 4.65 in precipitation, 1.8 in snowfall 4.7❄2 MarApril: 4.06 in precipitation 4.1 AprMay: 3.76 in precipitation 3.8 MayJune: 4.71 in precipitation 4.7 JunJuly: 5.17 in precipitation 5.2 JulAugust: 4.39 in precipitation 4.4 AugSeptember: 5.13 in precipitation 5.1 SepOctober: 4.12 in precipitation 4.1 OctNovember: 3.25 in precipitation, 0.1 in snowfall 3.3 NovDecember: 4.37 in precipitation, 0.8 in snowfall 4.4❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wilmington Porter Rsch, DE (2 mi away); precipitation: Wilmington Porter Rsch, DE (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

198847b
Wilmington, DE · <1 mi
198857b
Wilmington, DE · <1 mi
198867b
Wilmington, DE · <1 mi
198937b
Wilmington, DE · <1 mi
198947b
Wilmington, DE · <1 mi
198957b
Wilmington, DE · <1 mi
198997b
Wilmington, DE · <1 mi
198027b
Wilmington, DE · 1 mi

All 25 ZIP codes in Wilmington → · Delaware planting zones →

Questions about 19898

What planting zone is ZIP code 19898?

ZIP code 19898 (Wilmington, DE) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Wilmington, DE?

The median last spring frost (32 °F) near 19898 is April 7; after April 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wilmington Porter Rsch station.

When is the first frost in Wilmington, DE?

The median first fall frost near 19898 is November 4, giving a median frost-free growing season of 209 days.

When should I plant tomatoes in 19898?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 19898 get?

About 50.3 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, Wilmington Porter Rsch station).

How hot do summers get in Wilmington, DE?

The average high peaks at 84 °F in July, with about 17 days a year at 90 °F or more.

What kind of soil does 19898 have?

The USDA soil survey maps Udorthents at the center of ZIP 19898: silt loam, pH about 5.8 (moderately acidic).

Did spring come early in Wilmington, DE in 2026?

Spring leaf-out near 19898 came on Mar 15 in 2026, 4 days earlier than the 1991–2020 average (Mar 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Wilmington, DE?

Intermediate onions: the longest day near 19898 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 19898 change?

Yes. The 2012 USDA map put 19898 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.