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

Planting zone for 21795 — Williamsport, MD

ZIP code 21795 (Williamsport, Washington County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 11 and the first fall frost October 28.

Where ZIP 21795 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 11
First frostOct 28
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 Williamsport, 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 Williamsport, MD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 11median — 50% chance of a later frost
Safe for tender plantsApril 27only 10% chance of frost after
First fall frostOctober 28median — 10% chance by Oct 14
Growing season199 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 31 and returns around November 9.

From the NOAA station Hagerstown 1 E, MD — 8 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 21795

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 28 – Mar 14
SpinachSow outdoors · Feb 28 – Mar 21
Broccoli, cabbageStart indoors · Jan 31 – Feb 14
Broccoli, cabbageTransplant · Mar 21 – Apr 4
Onion setsPlant outdoors · Mar 14 – Mar 28
PotatoesPlant outdoors · Mar 21 – Apr 4
LettuceSow outdoors · Mar 14 – Mar 28
Carrots, beetsSow outdoors · Mar 21 – Apr 4
TomatoesStart indoors · Feb 14 – Feb 28
TomatoesTransplant · Apr 18 – May 2
Peppers, eggplantStart indoors · Jan 31 – Feb 14
Peppers, eggplantTransplant · Apr 25 – May 9
BeansSow outdoors · Apr 18 – May 2
Sweet cornSow outdoors · Apr 18 – May 2
Cucumbers, squashSow outdoors · Apr 18 – May 2
Fall lettuce, spinachSow outdoors · Sep 2 – Sep 16
GarlicPlant cloves · Oct 14 – Nov 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 28) 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 21795 came on Mar 12 — 9 days earlier than the 1991–2020 average (Mar 21).

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).

Soil in Williamsport, MD

The soil mapped at the center of ZIP 21795 is Hagerstown — silty clay loam, well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.9neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Hagerstown-Rock outcrop complex, 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 21795; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Williamsport, MD

Summer high86 °Faverage high, July
Winter low22 °Faverage low, January
Hot days32days a year at 90 °F or more
Freezing nights103nights a year at 32 °F or less
Growing degree days3,591base 50 °F — the season’s usable heat
Longest day14 h 58 mindaylight on June 21
Shortest day9 h 22 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation42.5 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 40 °F, low 22 °F 40°22° JanFebruary: average high 44 °F, low 25 °F 44°25° FebMarch: average high 53 °F, low 32 °F 53°32° MarApril: average high 65 °F, low 41 °F 65°41° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 83 °F, low 62 °F 83°62° JunJuly: average high 86 °F, low 66 °F 86°66° JulAugust: average high 85 °F, low 65 °F 85°65° AugSeptember: average high 78 °F, low 56 °F 78°56° SepOctober: average high 66 °F, low 45 °F 66°45° OctNovember: average high 54 °F, low 34 °F 54°34° NovDecember: average high 44 °F, low 27 °F 44°27° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.11 in precipitation 3.1 JanFebruary: 2.26 in precipitation 2.3 FebMarch: 4.00 in precipitation 4.0 MarApril: 3.30 in precipitation 3.3 AprMay: 4.25 in precipitation 4.3 MayJune: 4.03 in precipitation 4.0 JunJuly: 3.94 in precipitation 3.9 JulAugust: 3.41 in precipitation 3.4 AugSeptember: 4.13 in precipitation 4.1 SepOctober: 3.40 in precipitation 3.4 OctNovember: 3.16 in precipitation 3.2 NovDecember: 3.49 in precipitation 3.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hagerstown 1 E, MD (8 mi away); precipitation: Williamsport, MD (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.

254197a
Falling Waters, WV · 3 mi
217817a
Saint James, MD · 3 mi
217337a
Fairplay, MD · 4 mi
217407a
Hagerstown, MD · 6 mi
217467a
Hagerstown, MD · 6 mi
217347a
Funkstown, MD · 7 mi
217417a
Hagerstown, MD · 7 mi
217477b
Hagerstown, MD · 7 mi

Maryland planting zones →

Questions about 21795

What planting zone is ZIP code 21795?

ZIP code 21795 (Williamsport, MD) 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 Williamsport, MD?

The median last spring frost (32 °F) near 21795 is April 11; after April 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hagerstown 1 E station.

When is the first frost in Williamsport, MD?

The median first fall frost near 21795 is October 28, giving a median frost-free growing season of 199 days.

When should I plant tomatoes in 21795?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 21795 get?

About 42.5 inches of precipitation a year (NOAA 1991–2020 normals, Williamsport station).

How hot do summers get in Williamsport, MD?

The average high peaks at 86 °F in July, with about 32 days a year at 90 °F or more.

What kind of soil does 21795 have?

The USDA soil survey maps Hagerstown at the center of ZIP 21795: silty clay loam, well drained, pH about 6.9 (neutral).

Did spring come early in Williamsport, MD in 2026?

Spring leaf-out near 21795 came on Mar 12 in 2026, 9 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Williamsport, MD?

Intermediate onions: the longest day near 21795 is 14 h 58 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 21795 change?

Yes. The 2012 USDA map put 21795 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.