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

Planting zone for 21043 — Ellicott City, MD

ZIP code 21043 (Ellicott City, Howard County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 10 and the first fall frost October 31.

Where ZIP 21043 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.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostApr 10
First frostOct 31
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 Ellicott City, MD…

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 Ellicott City, MD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 10median — 50% chance of a later frost
Safe for tender plantsApril 25only 10% chance of frost after
First fall frostOctober 31median — 10% chance by Oct 17
Growing season204 daysfrost-free, median

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

From the NOAA station Baltimore Wash Intl Airport, MD — 9 miles away, elevation 157 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 21043

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 27 – Mar 13
SpinachSow outdoors · Feb 27 – Mar 20
Broccoli, cabbageStart indoors · Jan 30 – Feb 13
Broccoli, cabbageTransplant · Mar 20 – Apr 3
Onion setsPlant outdoors · Mar 13 – Mar 27
PotatoesPlant outdoors · Mar 20 – Apr 3
LettuceSow outdoors · Mar 13 – Mar 27
Carrots, beetsSow outdoors · Mar 20 – Apr 3
TomatoesStart indoors · Feb 13 – Feb 27
TomatoesTransplant · Apr 17 – May 1
Peppers, eggplantStart indoors · Jan 30 – Feb 13
Peppers, eggplantTransplant · Apr 24 – May 8
BeansSow outdoors · Apr 17 – May 1
Sweet cornSow outdoors · Apr 17 – May 1
Cucumbers, squashSow outdoors · Apr 17 – May 1
Fall lettuce, spinachSow outdoors · Sep 5 – Sep 19
GarlicPlant cloves · Oct 17 – Nov 21
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 10) and first fall frost (Oct 31) 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 21043 came on Mar 13 — 4 days earlier than the 1991–2020 average (Mar 17).

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 Maryland

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

Trees 83

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 127

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 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 °F

Wildflowers & perennials 206

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 176

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

Vines 12

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 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °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 Ellicott City, MD.

Soil in Ellicott City, MD

The soil mapped at the center of ZIP 21043 is Watchung — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter0.24%low — add compost
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Watchung silt loam, 3 to 8 percent slopes, stony.

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 21043; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ellicott City, MD

Summer high89 °Faverage high, July
Winter low25 °Faverage low, January
Hot days34days a year at 90 °F or more
Freezing nights93nights a year at 32 °F or less
Growing degree days4,007base 50 °F — the season’s usable heat
Longest day14 h 56 mindaylight on June 21
Shortest day9 h 24 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation51 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 43 °F, low 25 °F 43°25° JanFebruary: average high 46 °F, low 27 °F 46°27° FebMarch: average high 55 °F, low 34 °F 55°34° MarApril: average high 67 °F, low 44 °F 67°44° AprMay: average high 76 °F, low 53 °F 76°53° MayJune: average high 84 °F, low 63 °F 84°63° JunJuly: average high 89 °F, low 68 °F 89°68° JulAugust: average high 87 °F, low 66 °F 87°66° AugSeptember: average high 80 °F, low 59 °F 80°59° SepOctober: average high 68 °F, low 47 °F 68°47° OctNovember: average high 57 °F, low 37 °F 57°37° NovDecember: average high 48 °F, low 30 °F 48°30° Dec

Precipitation by month inches

0″2″4″6″January: 3.49 in precipitation 3.5 JanFebruary: 2.89 in precipitation 2.9 FebMarch: 4.24 in precipitation 4.2 MarApril: 3.66 in precipitation 3.7 AprMay: 6.35 in precipitation 6.3 MayJune: 4.58 in precipitation 4.6 JunJuly: 5.21 in precipitation 5.2 JulAugust: 4.39 in precipitation 4.4 AugSeptember: 4.68 in precipitation 4.7 SepOctober: 4.33 in precipitation 4.3 OctNovember: 3.41 in precipitation 3.4 NovDecember: 3.80 in precipitation 3.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Baltimore Wash Intl Airport, MD (9 mi away); precipitation: Catonsville 1.2 Nw, MD (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

212287b
Catonsville, MD · 3 mi
210457b
Columbia, MD · 4 mi
210757b
Elkridge, MD · 5 mi
212507b
Baltimore, MD · 5 mi
210427b
Ellicott City, MD · 5 mi
210447b
Columbia, MD · 5 mi
212447b
Windsor Mill, MD · 6 mi
210467b
Columbia, MD · 6 mi

All 3 ZIP codes in Ellicott City → · Maryland planting zones →

Questions about 21043

What planting zone is ZIP code 21043?

ZIP code 21043 (Ellicott City, MD) 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 Ellicott City, MD?

The median last spring frost (32 °F) near 21043 is April 10; after April 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Baltimore Wash Intl Airport station.

When is the first frost in Ellicott City, MD?

The median first fall frost near 21043 is October 31, giving a median frost-free growing season of 204 days.

When should I plant tomatoes in 21043?

Start tomato seeds indoors around Feb 13 – Feb 27 and set transplants outside around Apr 17 – May 1, one to three weeks after the median last frost.

How much rain and snow does 21043 get?

About 51 inches of precipitation a year (NOAA 1991–2020 normals, Catonsville 1.2 Nw station).

How hot do summers get in Ellicott City, MD?

The average high peaks at 89 °F in July, with about 34 days a year at 90 °F or more.

What kind of soil does 21043 have?

The USDA soil survey maps Watchung at the center of ZIP 21043: silt loam, poorly drained, pH about 5.8 (moderately acidic).

Did spring come early in Ellicott City, MD in 2026?

Spring leaf-out near 21043 came on Mar 13 in 2026, 4 days earlier than the 1991–2020 average (Mar 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ellicott City, MD?

Intermediate onions: the longest day near 21043 is 14 h 56 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 21043 change?

Yes. The 2012 USDA map put 21043 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.