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

Planting zone for 16405 — Columbus, PA

ZIP code 16405 (Columbus, Warren County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 22 and the first fall frost September 30.

Where ZIP 16405 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 frostMay 22

First frostSep 30

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Columbus, 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 Columbus, PA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 22median — 50% chance of a later frost

Safe for tender plantsJune 5only 10% chance of frost after

First fall frostSeptember 30median — 10% chance by Sep 16

Growing season131 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around October 11.

From the NOAA station Chandlers Valley 1se, PA — 12 miles away, elevation 1,490 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 16405

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 10 – Apr 24

SpinachSow outdoors · Apr 10 – May 1

Broccoli, cabbageStart indoors · Mar 13 – Mar 27

Broccoli, cabbageTransplant · May 1 – May 15

Onion setsPlant outdoors · Apr 24 – May 8

PotatoesPlant outdoors · May 1 – May 15

LettuceSow outdoors · Apr 24 – May 8

Carrots, beetsSow outdoors · May 1 – May 15

TomatoesStart indoors · Mar 27 – Apr 10

TomatoesTransplant · May 29 – Jun 12

Peppers, eggplantStart indoors · Mar 13 – Mar 27

Peppers, eggplantTransplant · Jun 5 – Jun 19

BeansSow outdoors · May 29 – Jun 12

Sweet cornSow outdoors · May 29 – Jun 12

Cucumbers, squashSow outdoors · May 29 – Jun 12

Fall lettuce, spinachSow outdoors · Aug 5 – Aug 19

GarlicPlant cloves · Sep 16 – Oct 21

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 22) and first fall frost (Sep 30) 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 16405 came on Mar 31 — 11 days earlier than the 1991–2020 average (Apr 11).

average
Apr 112026
Mar 31

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.

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 Columbus, PA.

Soil in Columbus, PA

The soil mapped at the center of ZIP 16405 is Mardin — gravelly silt loam, moderately well drained.

TextureGravelly silt loama good balance for most vegetables

pH5.1strongly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter4%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Mardin gravelly silt loam, 8 to 15 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 16405; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Columbus, PA

Summer high80 °Faverage high, July

Winter low12 °Faverage low, February

Hot days3days a year at 90 °F or more

Freezing nights173nights a year at 32 °F or less

Growing degree days2,004base 50 °F — the season’s usable heat

Longest day15 h 14 mindaylight on June 21

Shortest day9 h 07 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation48.9 inper year, rain and melted snow

Snowfall116 inper year; 88 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: Chandlers Valley 1se, PA (12 mi away); precipitation: Chandlers Valley 1se, PA (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

164025b

Bear Lake, PA · 4 mi

164365b

Spring Creek, PA · 5 mi

Sugar Grove, PA · 10 mi

Pennsylvania planting zones →

Questions about 16405

What planting zone is ZIP code 16405?

ZIP code 16405 (Columbus, PA) 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 Columbus, PA?

The median last spring frost (32 °F) near 16405 is May 22; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Chandlers Valley 1se station.

When is the first frost in Columbus, PA?

The median first fall frost near 16405 is September 30, giving a median frost-free growing season of 131 days.

When should I plant tomatoes in 16405?

Start tomato seeds indoors around Mar 27 – Apr 10 and set transplants outside around May 29 – Jun 12, one to three weeks after the median last frost.

How much rain and snow does 16405 get?

About 48.9 inches of precipitation a year and 116 inches of snowfall (NOAA 1991–2020 normals, Chandlers Valley 1se station).

How hot do summers get in Columbus, PA?

The average high peaks at 80 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 16405 have?

The USDA soil survey maps Mardin at the center of ZIP 16405: gravelly silt loam, moderately well drained, pH about 5.1 (strongly acidic).

Did spring come early in Columbus, PA in 2026?

Spring leaf-out near 16405 came on Mar 31 in 2026, 11 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Columbus, PA?

Long-day onions: the longest day near 16405 is 15 h 14 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 16405 change?

Yes. The 2012 USDA map put 16405 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.