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

Planting zone for 12950 — Lewis, NY

ZIP code 12950 (Lewis, Essex County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 2 and the first fall frost October 14.

Where ZIP 12950 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostMay 2

First frostOct 14

2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Lewis, NY…

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 Lewis, NY

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 2median — 50% chance of a later frost

Safe for tender plantsMay 16only 10% chance of frost after

First fall frostOctober 14median — 10% chance by Oct 2

Growing season165 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 28.

From the NOAA station Willsboro 1 N, NY — 11 miles away, elevation 180 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 12950

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 21 – Apr 4

SpinachSow outdoors · Mar 21 – Apr 11

Broccoli, cabbageStart indoors · Feb 21 – Mar 7

Broccoli, cabbageTransplant · Apr 11 – Apr 25

Onion setsPlant outdoors · Apr 4 – Apr 18

PotatoesPlant outdoors · Apr 11 – Apr 25

LettuceSow outdoors · Apr 4 – Apr 18

Carrots, beetsSow outdoors · Apr 11 – Apr 25

TomatoesStart indoors · Mar 7 – Mar 21

TomatoesTransplant · May 9 – May 23

Peppers, eggplantStart indoors · Feb 21 – Mar 7

Peppers, eggplantTransplant · May 16 – May 30

BeansSow outdoors · May 9 – May 23

Sweet cornSow outdoors · May 9 – May 23

Cucumbers, squashSow outdoors · May 9 – May 23

Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2

GarlicPlant cloves · Sep 30 – Nov 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 14) 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 12950 came on Apr 18 — 5 days earlier than the 1991–2020 average (Apr 23).

average
Apr 232026
Apr 18

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).

Soil in Lewis, NY

The soil mapped at the center of ZIP 12950 is Becket — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer

pH4.9strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter70%high

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Becket-Tunbridge complex, 15 to 35 percent slopes, rocky, very bouldery.

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 12950; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lewis, NY

Summer high80 °Faverage high, July

Winter low11 °Faverage low, January

Hot days6days a year at 90 °F or more

Freezing nights145nights a year at 32 °F or less

Growing degree days2,445base 50 °F — the season’s usable heat

Longest day15 h 32 mindaylight on June 21

Shortest day8 h 51 mindaylight on December 21

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

Precipitation37.9 inper year, rain and melted snow

Snowfall64 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Willsboro 1 N, NY (11 mi away); precipitation: Elizabethtown, NY (7 mi away). 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.

Elizabethtown, NY · 7 mi

129445a

Keeseville, NY · 8 mi

Keeseville, NY · 11 mi

New York planting zones →

Questions about 12950

What planting zone is ZIP code 12950?

ZIP code 12950 (Lewis, NY) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Lewis, NY?

The median last spring frost (32 °F) near 12950 is May 2; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Willsboro 1 N station.

When is the first frost in Lewis, NY?

The median first fall frost near 12950 is October 14, giving a median frost-free growing season of 165 days.

When should I plant tomatoes in 12950?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 12950 get?

About 37.9 inches of precipitation a year and 64 inches of snowfall (NOAA 1991–2020 normals, Elizabethtown station).

How hot do summers get in Lewis, NY?

The average high peaks at 80 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 12950 have?

The USDA soil survey maps Becket at the center of ZIP 12950: moderately decomposed plant material, well drained, pH about 4.9 (strongly acidic).

Did spring come early in Lewis, NY in 2026?

Spring leaf-out near 12950 came on Apr 18 in 2026, 5 days earlier than the 1991–2020 average (Apr 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lewis, NY?

Long-day onions: the longest day near 12950 is 15 h 32 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 12950 change?

Yes. The 2012 USDA map put 12950 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.