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

Planting zone for Watertown, NY

Watertown, NY is in USDA zone 5a across its 2 ZIP codes. The median last spring frost is May 2 and the first fall frost October 13.

Watertown on the zone map

Outlined: its 2 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.

Zone5a−20 to −15 °F

ZIP codes2

Last frostMay 2

First frostOct 13

Growing season163 days

5a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Watertown, 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 Watertown, 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 17only 10% chance of frost after

First fall frostOctober 13median — 10% chance by Oct 1

Growing season163 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 22 and returns around October 25.

From the NOAA station Watertown, NY, elevation 499 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 Watertown

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 18 – Sep 1

GarlicPlant cloves · Sep 29 – Nov 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 13) 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 13603 came on Apr 13 — 5 days earlier than the 1991–2020 average (Apr 18).

average
Apr 182026
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 5a in New York

584 plants native to the lower 48 states, recorded in New York, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 Watertown, NY.

Soil in Watertown, NY

The soil mapped at the center of ZIP 13603 is Plainfield — sand, excessively drained.

TextureSanddrains and warms fast; dries out and needs more feeding

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageExcessively drainednatural drainage class

Organic matter2%moderate

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Plainfield and Windsor soils, hilly.

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 13603; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Watertown, NY

Summer high80 °Faverage high, July

Winter low11 °Faverage low, January

Hot days4days a year at 90 °F or more

Freezing nights144nights a year at 32 °F or less

Growing degree days2,547base 50 °F — the season’s usable heat

Longest day15 h 29 mindaylight on June 21

Shortest day8 h 53 mindaylight on December 21

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

Precipitation45.1 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Watertown, NY (5 mi away); precipitation: Black Rvr, NY (2 mi away). Daylight is calculated from latitude.

ZIP codes in Watertown

New York planting zones →

Questions about Watertown

What planting zone is Watertown, NY?

Watertown, NY is in USDA hardiness zone 5a on the 2023 map (5a: −20 to −15 °F).

When is the last frost in Watertown, NY?

The median last spring frost is May 2 and the median first fall frost is October 13 (NOAA 1991–2020 normals, Watertown station).

When can I plant a garden in Watertown, NY?

Cool-season crops like peas and spinach go in around Mar 21 – Apr 11; tomatoes, peppers, beans and squash after about May 9, once frost risk has passed.

What kind of onions grow in Watertown, NY?

Long-day onions: the longest day is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Watertown, NY get?

About 45.1 inches of precipitation a year (NOAA 1991–2020 normals).