What USDA hardiness zone is Sullivan County, New York?

Sullivan County, New York spans USDA hardiness zones 5b to 6b. 71% of its ZIP codes are zone 6a, so there is no single zone for the county.

When is the last spring frost in Sullivan County, New York?

The median last spring freeze runs April 21 – May 12 across the 8 NOAA weather stations serving Sullivan County, New York, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

New York

Planting zones in Sullivan County, New York

This county spans USDA zones 5b to 6b, so there is no single zone for Sullivan County and anyone who gives you one is rounding. 71% of its ZIP codes are zone 6a; the rest are not.

USDA zones 5b–6b 3 zones across 52 ZIP codes

ZIP codes 52 52 have a NOAA station within range

Weather stations 8 NOAA 1991–2020 normals, across 968 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Sullivan County, New York as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.

The growing season in Sullivan County is closing

Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives October 4 – October 22 across the 8 NOAA stations serving this county .

Your next season already has a date

The first job of it is 🧅 Green Onions, start indoors, around February 24 – March 17 — counted back from a last spring freeze of April 21 – May 12 here.

Every spring date for your ZIP →

These are ranges across the whole county. The ZIP lookup above gives the dates from your own nearest station instead.

All 8 stations agreeAt least one station

Every one of the 8 NOAA stations serving this county counts May 12 – October 4 as growing season (145 days). Widening to any single station gives April 21 – October 22 (184 days).

That is a 39-day difference inside one county — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.

Which zone you are in depends where you are

Sullivan County covers 3 hardiness zones. A guide that gives the county one zone has picked whichever is largest and rounded everyone else into it — fine for the 71% in zone 6a and wrong for the other 29%. Here is the actual split.

Zone	ZIP codes	Share
6a	37	71%
5b	8	15%
6b	7	13%

Zones are published per ZIP code, so yours is exact even though the county's is not. The hardiness tool will tell you which one you are in.

Your freeze dates

Last spring freeze April 21 – May 12

First fall freeze October 4 – October 22

Across the 8 NOAA stations serving this county. These are medians — half of years freeze later than the date shown — so treat the later end of each range as the cautious one.

The growing season runs 146–182 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 76.6–81.3 °F in June–August. Summer rain over the same months runs 12.0–15.3" across those 8 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. At the middle station that is covered, so watering in Sullivan County is for the gaps between storms rather than the whole season. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 80 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Sullivan County

Zones are published per ZIP code, not per county, so this is the exact answer rather than the county's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.

ZIP code	USDA zone	Nearest NOAA station	Distance
12483	6b	Rock Hill 3 SW, NY	16.1 km
12701	6a	Rock Hill 3 SW, NY	9.6 km
12719	6a	Matamoras, PA	18.0 km
12720	6a	Milanville, PA	13.9 km
12721	6b	Middletown 2 NW, NY	12.0 km
12722	6b	Montgomery Orange AP, NY	12.9 km
12723	6a	Callicoon Ctr, NY	8.8 km
12724	5b	Callicoon Ctr, NY	3.8 km
12726	6a	Milanville, PA	8.5 km
12732	6a	Milanville, PA	20.5 km
12733	6a	Liberty 1 NE, NY	12.6 km
12734	6a	Liberty 1 NE, NY	7.5 km
12736	5b	Callicoon Ctr, NY	6.4 km
12737	6a	Matamoras, PA	14.0 km
12738	6a	Rock Hill 3 SW, NY	8.4 km
12741	5b	Callicoon Ctr, NY	10.6 km
12742	6a	Liberty 1 NE, NY	9.0 km
12743	6a	Matamoras, PA	19.0 km
12745	6a	Callicoon Ctr, NY	7.9 km
12747	6a	Liberty 1 NE, NY	9.9 km
12748	6a	Callicoon Ctr, NY	6.6 km
12749	6a	Liberty 1 NE, NY	14.1 km
12750	6a	Callicoon Ctr, NY	9.9 km
12751	6a	Rock Hill 3 SW, NY	11.4 km
12752	6a	Milanville, PA	6.6 km
12754	6a	Liberty 1 NE, NY	0.5 km
12758	5b	Liberty 1 NE, NY	15.4 km
12759	6a	Liberty 1 NE, NY	6.8 km
12762	6a	Liberty 1 NE, NY	16.3 km
12763	6a	Rock Hill 3 SW, NY	13.3 km
12764	6a	Milanville, PA	10.7 km
12765	6a	Liberty 1 NE, NY	11.3 km
12766	5b	Callicoon Ctr, NY	2.7 km
12767	5b	Callicoon Ctr, NY	4.4 km
12768	5b	Liberty 1 NE, NY	7.0 km
12769	6b	Rock Hill 3 SW, NY	14.1 km
12770	6a	Matamoras, PA	12.0 km
12775	6a	Rock Hill 3 SW, NY	4.3 km
12777	6a	Rock Hill 3 SW, NY	8.6 km
12778	6a	Liberty 1 NE, NY	16.7 km
12779	6a	Rock Hill 3 SW, NY	11.1 km
12781	6b	Rock Hill 3 SW, NY	12.1 km
12783	6a	Liberty 1 NE, NY	10.5 km
12784	6a	Rock Hill 3 SW, NY	8.4 km
12785	6b	Rock Hill 3 SW, NY	5.2 km
12786	6a	Milanville, PA	17.6 km
12787	6a	Liberty 1 NE, NY	8.7 km
12788	6a	Liberty 1 NE, NY	12.4 km
12789	6a	Rock Hill 3 SW, NY	14.4 km
12790	6b	Rock Hill 3 SW, NY	7.9 km
12791	5b	Callicoon Ctr, NY	4.9 km
12792	6a	Hawley 1 E, PA	17.6 km

ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.

When to start seeds in Sullivan County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 8 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	February 24 – March 17	8 wk before
🌶️ Peppers	Start indoors	February 24 – March 17	8 wk before
🥦 Broccoli	Start indoors	March 10 – March 31	6 wk before
🥬 Cabbage	Start indoors	March 10 – March 31	6 wk before
🥬 Collards	Start indoors	March 10 – March 31	6 wk before
🥬 Kale	Start indoors	March 10 – March 31	6 wk before
🥬 Leaf Lettuce	Start indoors	March 10 – March 31	6 wk before
🫛 Peas	Direct sow	March 10 – March 31	6 wk before
🥬 Spinach	Direct sow	March 10 – March 31	6 wk before
🍠 Sweet Potato	Start indoors	March 10 – March 31	6 wk before
🍅 Tomatoes	Start indoors	March 10 – March 31	6 wk before
🥬 Bok Choy	Start indoors	March 17 – April 7	5 wk before
🥬 Kohlrabi	Start indoors	March 17 – April 7	5 wk before
🥬 Swiss Chard	Start indoors	March 17 – April 7	5 wk before
🥬 Arugula	Direct sow	March 24 – April 14	4 wk before
🥬 Baby Salad Greens	Direct sow	March 24 – April 14	4 wk before
🥕 Beets	Direct sow	March 24 – April 14	4 wk before
🧅 Green Onions	Direct sow	March 24 – April 14	4 wk before
🥬 Mustard Greens	Direct sow	March 24 – April 14	4 wk before
🌶️ Okra	Start indoors	March 24 – April 14	4 wk before
🌱 Radishes	Direct sow	March 24 – April 14	4 wk before
🥔 Turnips	Direct sow	March 24 – April 14	4 wk before
🥬 Cabbage	Set out	March 31 – April 21	3 wk before
🥕 Carrots	Direct sow	March 31 – April 21	3 wk before
🥬 Collards	Direct sow	March 31 – April 21	3 wk before
🥬 Collards	Set out	March 31 – April 21	3 wk before
🥒 Cucumbers	Start indoors	March 31 – April 21	3 wk before
🧅 Green Onions	Set out	March 31 – April 21	3 wk before
🥬 Kale	Direct sow	March 31 – April 21	3 wk before
🥬 Kale	Set out	March 31 – April 21	3 wk before
🥬 Kohlrabi	Direct sow	March 31 – April 21	3 wk before
🥬 Kohlrabi	Set out	March 31 – April 21	3 wk before
🥬 Leaf Lettuce	Direct sow	March 31 – April 21	3 wk before
🎃 Pumpkins	Start indoors	March 31 – April 21	3 wk before
🎃 Summer Squash	Start indoors	March 31 – April 21	3 wk before
🎃 Winter Squash	Start indoors	March 31 – April 21	3 wk before
🥒 Zucchini	Start indoors	March 31 – April 21	3 wk before
🥬 Bok Choy	Direct sow	April 7 – April 28	2 wk before
🥬 Bok Choy	Set out	April 7 – April 28	2 wk before
🥦 Broccoli	Set out	April 7 – April 28	2 wk before
🌿 Cilantro	Direct sow	April 7 – April 28	2 wk before
🥬 Leaf Lettuce	Set out	April 7 – April 28	2 wk before
🥬 Swiss Chard	Direct sow	April 7 – April 28	2 wk before
🥬 Swiss Chard	Set out	April 7 – April 28	2 wk before
🌿 Dill	Direct sow	April 14 – May 5	1 wk before
🫘 Bush Beans	Direct sow	April 28 – May 19	1 wk after
🥒 Cucumbers	Set out	April 28 – May 19	1 wk after
🎃 Pumpkins	Direct sow	April 28 – May 19	1 wk after
🎃 Pumpkins	Set out	April 28 – May 19	1 wk after
🎃 Summer Squash	Direct sow	April 28 – May 19	1 wk after
🎃 Summer Squash	Set out	April 28 – May 19	1 wk after
🌽 Sweet Corn	Direct sow	April 28 – May 19	1 wk after
🍅 Tomatoes	Set out	April 28 – May 19	1 wk after
🎃 Winter Squash	Direct sow	April 28 – May 19	1 wk after
🎃 Winter Squash	Set out	April 28 – May 19	1 wk after
🥒 Zucchini	Direct sow	April 28 – May 19	1 wk after
🥒 Zucchini	Set out	April 28 – May 19	1 wk after
🥒 Cucumbers	Direct sow	May 5 – May 26	2 wk after
🌶️ Okra	Direct sow	May 5 – May 26	2 wk after
🌶️ Okra	Set out	May 5 – May 26	2 wk after
🌶️ Peppers	Set out	May 5 – May 26	2 wk after
🫘 Southern Peas	Direct sow	May 5 – May 26	2 wk after
🍠 Sweet Potato	Set out	May 5 – May 26	2 wk after

Offsets are published guidance; the dates they land on are computed from measured NOAA normals. The seed-starting tool does this for your own ZIP code and counts the days.

What survives the winter changes across Sullivan County

Zone 6a carries 51 of 74 perennial edibles; zone 5b carries 48. The best number is not always the warmest zone — the count peaks in the middle and falls both ways, because the warm end loses plants to insufficient winter chill and summer heat, not to cold.

Hardiness ranges are a judgement, published by growers rather than measured; the zone they are compared against is measured. On a warm-end verdict, check with your local extension service — a coastal zone 8 and an inland zone 8 are not the same summer.

Cautious — shortens the seasonMedian across stationsOptimistic

Last spring freeze: Plan to May 28 to be careful. Median April 21 – May 12 across 8 stations; April 9 is the optimistic end.
First fall freeze: Plan to September 21 to be careful. Median October 4 – October 22 across 8 stations; November 4 is the optimistic end.

NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.

The 8 stations behind these numbers

All 8 NOAA stations whose normals this page quotes, spanning about 48 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole county.

A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.

These are the stations this county's ZIP codes actually cite as nearest — not a claim that each one sits inside its boundary, since a rural ZIP legitimately reaches over it. Every figure above comes from them, and each is named so you can check it.

Station	NOAA ID	Last spring freeze	First fall freeze	Season
Callicoon Ctr, NY	USC00301102	May 12	October 7	146 days
Hawley 1 E, PA	USC00363758	May 10	October 4	146 days
Liberty 1 NE, NY	USC00304731	May 9	October 5	149 days
Matamoras, PA	USC00365470	May 2	October 12	164 days
Middletown 2 NW, NY	USC00305310	April 21	October 22	182 days
Milanville, PA	USC00365738	May 3	October 9	156 days
Montgomery Orange AP, NY	USW00004789	May 1	October 11	163 days
Rock Hill 3 SW, NY	USC00307210	May 7	October 7	152 days

These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.

Your own ZIP

Work out your own dates

This page describes a whole county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.

Other places to compare

Sullivan County sits in New York. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.

More of New York

Counties with the same zones — 5b–6b

Matched on the exact zone set, not a dominant zone, so the winter answer on these pages really is the same one as here.

Gear

If you want to act on this

Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.

Trunk wrapZone 5b is cold enough that winter sun on a young trunk does more damage than the cold does.
Row cover and frost clothThe season here closes at the first fall freeze dated above — a cover buys back some of those days at the end.
MulchFor the perennials nearest their cold limit in zone 5b, where an insulated crown is what decides whether they come back.

As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.

Sources

Where these numbers come from

Hardiness zones are the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. Freeze dates and growing-season lengths are NOAA 1991–2020 Climate Normals, taken per station and cited above by name and NOAA ID.

County boundaries come from the Census ZCTA-to-county relation, which is what places each ZIP code — and which treats parishes, boroughs and census areas as county equivalents. No station is chosen to represent this county: every range above is taken across all of them and the count is stated, because picking one would be a judgement dressed as a measurement.