Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 21532 — Frostburg, MD

ZIP code 21532 (Frostburg, Allegany County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 29 and the first fall frost October 18.

Where ZIP 21532 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostApr 29

First frostOct 18

2012 zone6b

Was 6b on the 2012 map — half a zone colder now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Frostburg, 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 Frostburg, MD

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 29median — 50% chance of a later frost

Safe for tender plantsMay 15only 10% chance of frost after

First fall frostOctober 18median — 10% chance by Oct 5

Growing season171 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 17 and returns around October 29.

From the NOAA station Frostburg 2, MD — 2 miles away, elevation 2,169 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 21532

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 18 – Apr 1

SpinachSow outdoors · Mar 18 – Apr 8

Broccoli, cabbageStart indoors · Feb 18 – Mar 4

Broccoli, cabbageTransplant · Apr 8 – Apr 22

Onion setsPlant outdoors · Apr 1 – Apr 15

PotatoesPlant outdoors · Apr 8 – Apr 22

LettuceSow outdoors · Apr 1 – Apr 15

Carrots, beetsSow outdoors · Apr 8 – Apr 22

TomatoesStart indoors · Mar 4 – Mar 18

TomatoesTransplant · May 6 – May 20

Peppers, eggplantStart indoors · Feb 18 – Mar 4

Peppers, eggplantTransplant · May 13 – May 27

BeansSow outdoors · May 6 – May 20

Sweet cornSow outdoors · May 6 – May 20

Cucumbers, squashSow outdoors · May 6 – May 20

Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6

GarlicPlant cloves · Oct 4 – Nov 8

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 18) 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 21532 came on Mar 21 — 16 days earlier than the 1991–2020 average (Apr 6).

average
Apr 62026
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).

Native plants for zone 6a in Maryland

571 plants native to the lower 48 states, recorded in Maryland, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

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 Frostburg, MD.

Soil in Frostburg, MD

The center of ZIP 21532 is mapped as Stony land, steep: 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 21532; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Frostburg, MD

Summer high79 °Faverage high, July

Winter low19 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights132nights a year at 32 °F or less

Growing degree days2,508base 50 °F — the season’s usable heat

Longest day14 h 59 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

Precipitation45.2 inper year, rain and melted snow

Snowfall72 inper year; 70 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

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

Nearby ZIP codes

6 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

215436b

Midlothian, MD · 1 mi

215396a

Lonaconing, MD · 4 mi

215426b

Midland, MD · 4 mi

215286b

Eckhart Mines, MD · 4 mi

215216b

Barton, MD · 8 mi

215456b

Mount Savage, MD · 8 mi

215057a

Cumberland, MD · 8 mi

155326a

Boynton, PA · 9 mi

Maryland planting zones →

Questions about 21532

What planting zone is ZIP code 21532?

ZIP code 21532 (Frostburg, MD) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Frostburg, MD?

The median last spring frost (32 °F) near 21532 is April 29; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Frostburg 2 station.

When is the first frost in Frostburg, MD?

The median first fall frost near 21532 is October 18, giving a median frost-free growing season of 171 days.

When should I plant tomatoes in 21532?

Start tomato seeds indoors around Mar 4 – Mar 18 and set transplants outside around May 6 – May 20, one to three weeks after the median last frost.

How much rain and snow does 21532 get?

About 45.2 inches of precipitation a year and 72 inches of snowfall (NOAA 1991–2020 normals, Frostburg 2 station).

How hot do summers get in Frostburg, MD?

The average high peaks at 79 °F in July, with about 1 days a year at 90 °F or more.

Did spring come early in Frostburg, MD in 2026?

Spring leaf-out near 21532 came on Mar 21 in 2026, 16 days earlier than the 1991–2020 average (Apr 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Frostburg, MD?

Intermediate onions: the longest day near 21532 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 21532 change?

Yes. The 2012 USDA map put 21532 in zone 6b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.