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

Planting zone for 20172 — Herndon, VA

ZIP code 20172 (Herndon, Fairfax County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 15 and the first fall frost October 24.

Where ZIP 20172 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 15
First frostOct 24
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 Herndon, VA…

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 Herndon, VA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 15median — 50% chance of a later frost
Safe for tender plantsApril 30only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 10
Growing season194 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around November 4.

From the NOAA station Washington Dc Dulles Airport, VA — 4 miles away, 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 20172

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 4 – Mar 18
SpinachSow outdoors · Mar 4 – Mar 25
Broccoli, cabbageStart indoors · Feb 4 – Feb 18
Broccoli, cabbageTransplant · Mar 25 – Apr 8
Onion setsPlant outdoors · Mar 18 – Apr 1
PotatoesPlant outdoors · Mar 25 – Apr 8
LettuceSow outdoors · Mar 18 – Apr 1
Carrots, beetsSow outdoors · Mar 25 – Apr 8
TomatoesStart indoors · Feb 18 – Mar 4
TomatoesTransplant · Apr 22 – May 6
Peppers, eggplantStart indoors · Feb 4 – Feb 18
Peppers, eggplantTransplant · Apr 29 – May 13
BeansSow outdoors · Apr 22 – May 6
Sweet cornSow outdoors · Apr 22 – May 6
Cucumbers, squashSow outdoors · Apr 22 – May 6
Fall lettuce, spinachSow outdoors · Aug 29 – Sep 12
GarlicPlant cloves · Oct 10 – Nov 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 15) and first fall frost (Oct 24) 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 20172 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 7b in Virginia

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

Trees 89

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 133

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 200

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 181

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 Herndon, VA.

Soil in Herndon, VA

The center of ZIP 20172 is mapped as Urban land: 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 20172; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Herndon, VA

Summer high88 °Faverage high, July
Winter low25 °Faverage low, January
Hot days33days a year at 90 °F or more
Freezing nights102nights a year at 32 °F or less
Growing degree days3,886base 50 °F — the season’s usable heat
Longest day14 h 54 mindaylight on June 21
Shortest day9 h 26 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation46.4 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 43 °F 67°43° AprMay: average high 75 °F, low 53 °F 75°53° MayJune: average high 83 °F, low 62 °F 83°62° JunJuly: average high 88 °F, low 67 °F 88°67° JulAugust: average high 86 °F, low 65 °F 86°65° AugSeptember: average high 79 °F, low 58 °F 79°58° SepOctober: average high 68 °F, low 45 °F 68°45° OctNovember: average high 57 °F, low 36 °F 57°36° NovDecember: average high 47 °F, low 29 °F 47°29° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.10 in precipitation 3.1 JanFebruary: 2.80 in precipitation 2.8 FebMarch: 3.85 in precipitation 3.9 MarApril: 3.46 in precipitation 3.5 AprMay: 4.61 in precipitation 4.6 MayJune: 4.42 in precipitation 4.4 JunJuly: 4.67 in precipitation 4.7 JulAugust: 3.77 in precipitation 3.8 AugSeptember: 4.62 in precipitation 4.6 SepOctober: 4.29 in precipitation 4.3 OctNovember: 3.25 in precipitation 3.3 NovDecember: 3.59 in precipitation 3.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Washington Dc Dulles Airport, VA (4 mi away); precipitation: Herndon 3.3 S, VA (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

220957b
Herndon, VA · <1 mi
201707b
Herndon, VA · <1 mi
201907b
Reston, VA · 3 mi
201947b
Reston, VA · 3 mi
201647b
Sterling, VA · 3 mi
201717b
Herndon, VA · 3 mi
201917b
Reston, VA · 3 mi
201637b
Sterling, VA · 3 mi

All 4 ZIP codes in Herndon → · Virginia planting zones →

Questions about 20172

What planting zone is ZIP code 20172?

ZIP code 20172 (Herndon, VA) 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 Herndon, VA?

The median last spring frost (32 °F) near 20172 is April 15; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Washington Dc Dulles Airport station.

When is the first frost in Herndon, VA?

The median first fall frost near 20172 is October 24, giving a median frost-free growing season of 194 days.

When should I plant tomatoes in 20172?

Start tomato seeds indoors around Feb 18 – Mar 4 and set transplants outside around Apr 22 – May 6, one to three weeks after the median last frost.

How much rain and snow does 20172 get?

About 46.4 inches of precipitation a year (NOAA 1991–2020 normals, Herndon 3.3 S station).

How hot do summers get in Herndon, VA?

The average high peaks at 88 °F in July, with about 33 days a year at 90 °F or more.

Did spring come early in Herndon, VA in 2026?

Spring leaf-out near 20172 came on Mar 11 in 2026, 6 days earlier than the 1991–2020 average (Mar 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Herndon, VA?

Intermediate onions: the longest day near 20172 is 14 h 54 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 20172 change?

Yes. The 2012 USDA map put 20172 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.