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

Planting zone for Irvine, PA

Irvine, PA is in USDA zone 6a across its 3 ZIP codes. The median last spring frost is May 4 and the first fall frost October 21.

Irvine on the zone map

Outlined: its 1 ZIP code areas · 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
ZIP codes3
Last frostMay 4
First frostOct 21
Growing season168 days

6a 3 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Irvine, 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 Irvine, PA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 4median — 50% chance of a later frost
Safe for tender plantsMay 22only 10% chance of frost after
First fall frostOctober 21median — 10% chance by Oct 6
Growing season168 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around November 2.

From the NOAA station Warren, PA, elevation 1,211 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 Irvine

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 23 – Apr 6
SpinachSow outdoors · Mar 23 – Apr 13
Broccoli, cabbageStart indoors · Feb 23 – Mar 9
Broccoli, cabbageTransplant · Apr 13 – Apr 27
Onion setsPlant outdoors · Apr 6 – Apr 20
PotatoesPlant outdoors · Apr 13 – Apr 27
LettuceSow outdoors · Apr 6 – Apr 20
Carrots, beetsSow outdoors · Apr 13 – Apr 27
TomatoesStart indoors · Mar 9 – Mar 23
TomatoesTransplant · May 11 – May 25
Peppers, eggplantStart indoors · Feb 23 – Mar 9
Peppers, eggplantTransplant · May 18 – Jun 1
BeansSow outdoors · May 11 – May 25
Sweet cornSow outdoors · May 11 – May 25
Cucumbers, squashSow outdoors · May 11 – May 25
Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9
GarlicPlant cloves · Oct 7 – Nov 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 4) and first fall frost (Oct 21) 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 16368 came on Mar 27 — 17 days earlier than the 1991–2020 average (Apr 13).

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 Pennsylvania

598 plants native to the lower 48 states, recorded in Pennsylvania, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 121

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 207

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 170

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 9

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 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Irvine, PA.

Soil in Irvine, PA

The soil mapped at the center of ZIP 16368 is Buchanan — slightly decomposed plant material, moderately well drained.

TextureSlightly decomposed plant materialtop layer
pH4.5strongly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter69%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Buchanan silt loam, 8 to 25 percent slopes, extremely stony.

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 16368; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Irvine, PA

Summer high81 °Faverage high, July
Winter low18 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights141nights a year at 32 °F or less
Growing degree days2,568base 50 °F — the season’s usable heat
Longest day15 h 13 mindaylight on June 21
Shortest day9 h 08 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation47 inper year, rain and melted snow
Snowfall72 inper year; 70 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 33 °F, low 18 °F 33°18° JanFebruary: average high 35 °F, low 18 °F 35°18° FebMarch: average high 44 °F, low 24 °F 44°24° MarApril: average high 58 °F, low 34 °F 58°34° AprMay: average high 70 °F, low 45 °F 70°45° MayJune: average high 77 °F, low 55 °F 77°55° JunJuly: average high 81 °F, low 59 °F 81°59° JulAugust: average high 80 °F, low 58 °F 80°58° AugSeptember: average high 74 °F, low 52 °F 74°52° SepOctober: average high 61 °F, low 41 °F 61°41° OctNovember: average high 48 °F, low 32 °F 48°32° NovDecember: average high 37 °F, low 24 °F 37°24° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.64 in precipitation, 18.2 in snowfall 3.6❄18 JanFebruary: 2.77 in precipitation, 14.9 in snowfall 2.8❄15 FebMarch: 3.26 in precipitation, 10 in snowfall 3.3❄10 MarApril: 4.13 in precipitation, 2.4 in snowfall 4.1❄2 AprMay: 4.29 in precipitation 4.3 MayJune: 4.66 in precipitation 4.7 JunJuly: 4.76 in precipitation 4.8 JulAugust: 4.07 in precipitation 4.1 AugSeptember: 3.95 in precipitation 4.0 SepOctober: 4.02 in precipitation, 0.1 in snowfall 4.0 OctNovember: 3.62 in precipitation, 7.5 in snowfall 3.6❄8 NovDecember: 3.81 in precipitation, 18.5 in snowfall 3.8❄19 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Warren, PA (6 mi away); precipitation: Warren, PA (6 mi away). Daylight is calculated from latitude.

ZIP codes in Irvine

163296a
−10 to −5 °F
163686a
−10 to −5 °F
163696a
−10 to −5 °F

Pennsylvania planting zones →

Questions about Irvine

What planting zone is Irvine, PA?

Irvine, PA is in USDA hardiness zone 6a on the 2023 map (6a: −10 to −5 °F).

When is the last frost in Irvine, PA?

The median last spring frost is May 4 and the median first fall frost is October 21 (NOAA 1991–2020 normals, Warren station).

When can I plant a garden in Irvine, PA?

Cool-season crops like peas and spinach go in around Mar 23 – Apr 13; tomatoes, peppers, beans and squash after about May 11, once frost risk has passed.

What kind of onions grow in Irvine, PA?

Long-day onions: the longest day is 15 h 13 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Irvine, PA get?

About 47 inches of precipitation a year and 72 inches of snowfall (NOAA 1991–2020 normals).