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

Planting zone for Dulles, VA

Dulles, VA is in USDA zone 7a across its 5 ZIP codes. The median last spring frost is April 13 and the first fall frost October 26.

Dulles on the zone map

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
ZIP codes5
Last frostApr 13
First frostOct 26
Growing season195 days

7a 5 ZIPs

Frost forecast — next 7 nights

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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 Dulles, VA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 13median — 50% chance of a later frost
Safe for tender plantsMay 1only 10% chance of frost after
First fall frostOctober 26median — 10% chance by Oct 11
Growing season195 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 31 and returns around November 4.

From the NOAA station WFO Sterling, VA, elevation 289 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 Dulles

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 2 – Mar 16
SpinachSow outdoors · Mar 2 – Mar 23
Broccoli, cabbageStart indoors · Feb 2 – Feb 16
Broccoli, cabbageTransplant · Mar 23 – Apr 6
Onion setsPlant outdoors · Mar 16 – Mar 30
PotatoesPlant outdoors · Mar 23 – Apr 6
LettuceSow outdoors · Mar 16 – Mar 30
Carrots, beetsSow outdoors · Mar 23 – Apr 6
TomatoesStart indoors · Feb 16 – Mar 2
TomatoesTransplant · Apr 20 – May 4
Peppers, eggplantStart indoors · Feb 2 – Feb 16
Peppers, eggplantTransplant · Apr 27 – May 11
BeansSow outdoors · Apr 20 – May 4
Sweet cornSow outdoors · Apr 20 – May 4
Cucumbers, squashSow outdoors · Apr 20 – May 4
Fall lettuce, spinachSow outdoors · Aug 31 – Sep 14
GarlicPlant cloves · Oct 12 – Nov 16
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 13) and first fall frost (Oct 26) 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 20189 came on Mar 11 — 6 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 7a in Virginia

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

Trees 87

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 129

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 197

American 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 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 179

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 Dulles, VA.

Soil in Dulles, VA

The soil mapped at the center of ZIP 20189 is Albano — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables
pH5.3strongly acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter1.5%low — add compost
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Albano silt loam, 0 to 2 percent slopes, frequently flooded.

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 20189; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dulles, VA

Summer high87 °Faverage high, July
Winter low25 °Faverage low, January
Hot days32days a year at 90 °F or more
Freezing nights119nights a year at 32 °F or less
Growing degree days3,865base 50 °F — the season’s usable heat
Longest day14 h 55 mindaylight on June 21
Shortest day9 h 25 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation45.1 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 42 °F, low 25 °F 42°25° JanFebruary: average high 45 °F, low 26 °F 45°26° FebMarch: average high 54 °F, low 33 °F 54°33° MarApril: average high 66 °F, low 43 °F 66°43° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 83 °F, low 63 °F 83°63° JunJuly: average high 87 °F, low 67 °F 87°67° JulAugust: average high 86 °F, low 66 °F 86°66° AugSeptember: average high 79 °F, low 58 °F 79°58° SepOctober: average high 68 °F, low 45 °F 68°45° OctNovember: average high 56 °F, low 35 °F 56°35° NovDecember: average high 46 °F, low 29 °F 46°29° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.12 in precipitation 3.1 JanFebruary: 2.63 in precipitation 2.6 FebMarch: 3.79 in precipitation 3.8 MarApril: 3.45 in precipitation 3.5 AprMay: 4.92 in precipitation 4.9 MayJune: 4.61 in precipitation 4.6 JunJuly: 4.06 in precipitation 4.1 JulAugust: 3.65 in precipitation 3.6 AugSeptember: 4.13 in precipitation 4.1 SepOctober: 4.04 in precipitation 4.0 OctNovember: 3.21 in precipitation 3.2 NovDecember: 3.48 in precipitation 3.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: WFO Sterling, VA (3 mi away); precipitation: WFO Sterling, VA (3 mi away). Daylight is calculated from latitude.

ZIP codes in Dulles

201017a
0 to 5 °F
201027a
0 to 5 °F
201037a
0 to 5 °F
201047a
0 to 5 °F
201897a
0 to 5 °F

Virginia planting zones →

Questions about Dulles

What planting zone is Dulles, VA?

Dulles, VA is in USDA hardiness zone 7a on the 2023 map (7a: 0 to 5 °F).

When is the last frost in Dulles, VA?

The median last spring frost is April 13 and the median first fall frost is October 26 (NOAA 1991–2020 normals, WFO Sterling station).

When can I plant a garden in Dulles, VA?

Cool-season crops like peas and spinach go in around Mar 2 – Mar 23; tomatoes, peppers, beans and squash after about Apr 20, once frost risk has passed.

What kind of onions grow in Dulles, VA?

Intermediate onions: the longest day is 14 h 55 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Dulles, VA get?

About 45.1 inches of precipitation a year (NOAA 1991–2020 normals).