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

Planting zone for 16693 — Williamsburg, PA

ZIP code 16693 (Williamsburg, Blair County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 19 and the first fall frost October 28.

Where ZIP 16693 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 19
First frostOct 28
2012 zone6b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Williamsburg, PA…

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 Williamsburg, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 19median — 50% chance of a later frost
Safe for tender plantsMay 7only 10% chance of frost after
First fall frostOctober 28median — 10% chance by Oct 12
Growing season191 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 6 and returns around November 9.

From the NOAA station Raystown Lake 2, PA — 10 miles away, elevation 1,001 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 16693

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 8 – Mar 22
SpinachSow outdoors · Mar 8 – Mar 29
Broccoli, cabbageStart indoors · Feb 8 – Feb 22
Broccoli, cabbageTransplant · Mar 29 – Apr 12
Onion setsPlant outdoors · Mar 22 – Apr 5
PotatoesPlant outdoors · Mar 29 – Apr 12
LettuceSow outdoors · Mar 22 – Apr 5
Carrots, beetsSow outdoors · Mar 29 – Apr 12
TomatoesStart indoors · Feb 22 – Mar 8
TomatoesTransplant · Apr 26 – May 10
Peppers, eggplantStart indoors · Feb 8 – Feb 22
Peppers, eggplantTransplant · May 3 – May 17
BeansSow outdoors · Apr 26 – May 10
Sweet cornSow outdoors · Apr 26 – May 10
Cucumbers, squashSow outdoors · Apr 26 – May 10
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 19) 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 16693 came on Mar 16 — 18 days earlier than the 1991–2020 average (Apr 3).

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 6b in Pennsylvania

605 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 76

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 122

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 black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 209

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican 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 °F

Grasses 173

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °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 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °F

Vines 10

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °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 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °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 Williamsburg, PA.

Soil in Williamsburg, PA

The soil mapped at the center of ZIP 16693 is Hublersburg — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Hublersburg cherty silt loam, 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 16693; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Williamsburg, PA

Summer high85 °Faverage high, July
Winter low21 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights126nights a year at 32 °F or less
Growing degree days3,189base 50 °F — the season’s usable heat
Longest day15 h 04 mindaylight on June 21
Shortest day9 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation40.7 inper year, rain and melted snow
Snowfall26 inper year; 37 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 37 °F, low 21 °F 37°21° JanFebruary: average high 40 °F, low 22 °F 40°22° FebMarch: average high 49 °F, low 29 °F 49°29° MarApril: average high 62 °F, low 40 °F 62°40° AprMay: average high 72 °F, low 50 °F 72°50° MayJune: average high 80 °F, low 58 °F 80°58° JunJuly: average high 85 °F, low 63 °F 85°63° JulAugust: average high 84 °F, low 62 °F 84°62° AugSeptember: average high 76 °F, low 55 °F 76°55° SepOctober: average high 64 °F, low 44 °F 64°44° OctNovember: average high 52 °F, low 34 °F 52°34° NovDecember: average high 42 °F, low 27 °F 42°27° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.71 in precipitation, 7.5 in snowfall 2.7❄8 JanFebruary: 2.31 in precipitation, 6.8 in snowfall 2.3❄7 FebMarch: 3.40 in precipitation, 4.8 in snowfall 3.4❄5 MarApril: 3.38 in precipitation, 0.2 in snowfall 3.4 AprMay: 3.87 in precipitation 3.9 MayJune: 3.94 in precipitation 3.9 JunJuly: 3.60 in precipitation 3.6 JulAugust: 4.10 in precipitation 4.1 AugSeptember: 4.02 in precipitation 4.0 SepOctober: 3.28 in precipitation 3.3 OctNovember: 2.97 in precipitation, 1.3 in snowfall 3.0❄1 NovDecember: 3.09 in precipitation, 5.1 in snowfall 3.1❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Raystown Lake 2, PA (10 mi away); precipitation: Williamsburg, PA (within 1 mile). 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.

166486b
Hollidaysburg, PA · 6 mi
166477a
Hesston, PA · 8 mi
166386b
Entriken, PA · 9 mi
166026b
Altoona, PA · 9 mi
166576b
James Creek, PA · 9 mi
166016b
Altoona, PA · 10 mi
166036b
Altoona, PA · 10 mi
166116b
Alexandria, PA · 10 mi

Pennsylvania planting zones →

Questions about 16693

What planting zone is ZIP code 16693?

ZIP code 16693 (Williamsburg, PA) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Williamsburg, PA?

The median last spring frost (32 °F) near 16693 is April 19; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Raystown Lake 2 station.

When is the first frost in Williamsburg, PA?

The median first fall frost near 16693 is October 28, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 16693?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 16693 get?

About 40.7 inches of precipitation a year and 26 inches of snowfall (NOAA 1991–2020 normals, Williamsburg station).

How hot do summers get in Williamsburg, PA?

The average high peaks at 85 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 16693 have?

The USDA soil survey maps Hublersburg at the center of ZIP 16693: gravelly silt loam, well drained, pH about 6.0 (slightly acidic).

Did spring come early in Williamsburg, PA in 2026?

Spring leaf-out near 16693 came on Mar 16 in 2026, 18 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Williamsburg, PA?

Long-day onions: the longest day near 16693 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).