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

Planting zone for 12784 — Thompsonville, NY

ZIP code 12784 (Thompsonville, Sullivan County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 7 and the first fall frost October 7.

Where ZIP 12784 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 7
First frostOct 7
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 Thompsonville, 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 Thompsonville, NY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 7median — 50% chance of a later frost
Safe for tender plantsMay 22only 10% chance of frost after
First fall frostOctober 7median — 10% chance by Sep 25
Growing season152 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 20.

From the NOAA station Rock Hill 3 Sw, NY — 5 miles away, elevation 1,270 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 12784

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 26 – Apr 9
SpinachSow outdoors · Mar 26 – Apr 16
Broccoli, cabbageStart indoors · Feb 26 – Mar 12
Broccoli, cabbageTransplant · Apr 16 – Apr 30
Onion setsPlant outdoors · Apr 9 – Apr 23
PotatoesPlant outdoors · Apr 16 – Apr 30
LettuceSow outdoors · Apr 9 – Apr 23
Carrots, beetsSow outdoors · Apr 16 – Apr 30
TomatoesStart indoors · Mar 12 – Mar 26
TomatoesTransplant · May 14 – May 28
Peppers, eggplantStart indoors · Feb 26 – Mar 12
Peppers, eggplantTransplant · May 21 – Jun 4
BeansSow outdoors · May 14 – May 28
Sweet cornSow outdoors · May 14 – May 28
Cucumbers, squashSow outdoors · May 14 – May 28
Fall lettuce, spinachSow outdoors · Aug 12 – Aug 26
GarlicPlant cloves · Sep 23 – Oct 28
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 7) and first fall frost (Oct 7) 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 12784 came on Apr 5 — 8 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).

Soil in Thompsonville, NY

The soil mapped at the center of ZIP 12784 is Arnot — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
pH4.8strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter80%high
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Arnot-Lordstown complex, 0 to 15 percent slopes, very rocky.

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 12784; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Thompsonville, NY

Summer high80 °Faverage high, July
Winter low12 °Faverage low, February
Hot days2days a year at 90 °F or more
Freezing nights160nights a year at 32 °F or less
Growing degree days2,154base 50 °F — the season’s usable heat
Longest day15 h 12 mindaylight on June 21
Shortest day9 h 09 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation51.9 inper year, rain and melted snow
Snowfall58 inper year; 84 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 14 °F 32°14° JanFebruary: average high 35 °F, low 12 °F 35°12° FebMarch: average high 44 °F, low 20 °F 44°20° MarApril: average high 56 °F, low 32 °F 56°32° AprMay: average high 67 °F, low 44 °F 67°44° MayJune: average high 75 °F, low 53 °F 75°53° JunJuly: average high 80 °F, low 58 °F 80°58° JulAugust: average high 78 °F, low 56 °F 78°56° AugSeptember: average high 71 °F, low 48 °F 71°48° SepOctober: average high 59 °F, low 37 °F 59°37° OctNovember: average high 47 °F, low 28 °F 47°28° NovDecember: average high 36 °F, low 20 °F 36°20° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.73 in precipitation, 16.5 in snowfall 3.7❄17 JanFebruary: 3.14 in precipitation, 10.8 in snowfall 3.1❄11 FebMarch: 4.10 in precipitation, 12.9 in snowfall 4.1❄13 MarApril: 4.02 in precipitation, 2 in snowfall 4.0❄2 AprMay: 4.18 in precipitation 4.2 MayJune: 5.01 in precipitation 5.0 JunJuly: 4.76 in precipitation 4.8 JulAugust: 4.73 in precipitation 4.7 AugSeptember: 4.76 in precipitation 4.8 SepOctober: 5.06 in precipitation, 0.7 in snowfall 5.1❄1 OctNovember: 3.78 in precipitation, 2 in snowfall 3.8❄2 NovDecember: 4.63 in precipitation, 13 in snowfall 4.6❄13 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rock Hill 3 Sw, NY (5 mi away); precipitation: Rock Hill 3 Sw, NY (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

127386a
Glen Wild, NY · <1 mi
127796a
South Fallsburg, NY · 2 mi
127516a
Kiamesha Lake, NY · 3 mi
127756a
Rock Hill, NY · 4 mi
127896a
Woodridge, NY · 4 mi
127016a
Monticello, NY · 5 mi
127336a
Fallsburg, NY · 5 mi
127636a
Mountain Dale, NY · 5 mi

New York planting zones →

Questions about 12784

What planting zone is ZIP code 12784?

ZIP code 12784 (Thompsonville, NY) 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 Thompsonville, NY?

The median last spring frost (32 °F) near 12784 is May 7; after May 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rock Hill 3 Sw station.

When is the first frost in Thompsonville, NY?

The median first fall frost near 12784 is October 7, giving a median frost-free growing season of 152 days.

When should I plant tomatoes in 12784?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 12784 get?

About 51.9 inches of precipitation a year and 58 inches of snowfall (NOAA 1991–2020 normals, Rock Hill 3 Sw station).

How hot do summers get in Thompsonville, NY?

The average high peaks at 80 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 12784 have?

The USDA soil survey maps Arnot at the center of ZIP 12784: moderately decomposed plant material, well drained, pH about 4.8 (strongly acidic).

Did spring come early in Thompsonville, NY in 2026?

Spring leaf-out near 12784 came on Apr 5 in 2026, 8 days earlier than the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Thompsonville, NY?

Long-day onions: the longest day near 12784 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 12784 change?

Yes. The 2012 USDA map put 12784 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.