What USDA hardiness zone is Sevier County, Utah?

Every ZIP code in Sevier County, Utah is USDA hardiness zone 6a, from the USDA 2023 Plant Hardiness Zone Map.

When is the last spring frost in Sevier County, Utah?

The median last spring freeze runs May 21 – June 6 across the 5 NOAA weather stations serving Sevier County, Utah, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

Utah

Planting zones in Sevier County, Utah

Every ZIP code in this county is USDA zone 6a — so unlike most of the places people look up, there is one right answer here and it holds wherever you are in the county.

USDA zone 6a The same in all 12 ZIP codes

ZIP codes 12 12 have a NOAA station within range

Weather stations 5 NOAA 1991–2020 normals, across 1,910 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Sevier County, Utah 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 Sevier County is closing

Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives September 21 – September 26 across the 5 NOAA stations serving this county .

Your next season already has a date

The first job of it is 🧅 Green Onions, start indoors, around March 26 – April 11 — counted back from a last spring freeze of May 21 – June 6 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 5 stations agreeAt least one station

Every one of the 5 NOAA stations serving this county counts June 6 – September 21 as growing season (107 days). Widening to any single station gives May 21 – September 26 (128 days).

That is a 21-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.

Your freeze dates

Last spring freeze May 21 – June 6

First fall freeze September 21 – September 26

Across the 5 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 104–125 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 76.6–87.8 °F in June–August. Summer rain over the same months runs 1.8–3.4" across those 5 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. The middle station covers about 24% of it, so a summer garden here is watered rather than rained on. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 87 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Sevier 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
84620	6a	Richfield Radio Ksvc, UT	22.3 km
84652	6a	Scipio, UT	32.2 km
84654	6a	Salina 24 E, UT	23.4 km
84657	6a	Richfield Radio Ksvc, UT	13.6 km
84701	6a	Koosharem, UT	11.7 km
84711	6a	Richfield Radio Ksvc, UT	4.7 km
84724	6a	Richfield Radio Ksvc, UT	11.6 km
84730	6a	Richfield Radio Ksvc, UT	5.8 km
84739	6a	Fremont Indian SP, UT	12.1 km
84744	6a	Koosharem, UT	13.4 km
84754	6a	Richfield Radio Ksvc, UT	17.1 km
84766	6a	Fremont Indian SP, UT	2.5 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 Sevier County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 5 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	March 26 – April 11	8 wk before
🌶️ Peppers	Start indoors	March 26 – April 11	8 wk before
🥦 Broccoli	Start indoors	April 9 – April 25	6 wk before
🥬 Cabbage	Start indoors	April 9 – April 25	6 wk before
🥬 Collards	Start indoors	April 9 – April 25	6 wk before
🥬 Kale	Start indoors	April 9 – April 25	6 wk before
🥬 Leaf Lettuce	Start indoors	April 9 – April 25	6 wk before
🫛 Peas	Direct sow	April 9 – April 25	6 wk before
🥬 Spinach	Direct sow	April 9 – April 25	6 wk before
🍠 Sweet Potato	Start indoors	April 9 – April 25	6 wk before
🍅 Tomatoes	Start indoors	April 9 – April 25	6 wk before
🥬 Bok Choy	Start indoors	April 16 – May 2	5 wk before
🥬 Kohlrabi	Start indoors	April 16 – May 2	5 wk before
🥬 Swiss Chard	Start indoors	April 16 – May 2	5 wk before
🥬 Arugula	Direct sow	April 23 – May 9	4 wk before
🥬 Baby Salad Greens	Direct sow	April 23 – May 9	4 wk before
🥕 Beets	Direct sow	April 23 – May 9	4 wk before
🧅 Green Onions	Direct sow	April 23 – May 9	4 wk before
🥬 Mustard Greens	Direct sow	April 23 – May 9	4 wk before
🌶️ Okra	Start indoors	April 23 – May 9	4 wk before
🌱 Radishes	Direct sow	April 23 – May 9	4 wk before
🥔 Turnips	Direct sow	April 23 – May 9	4 wk before
🥬 Cabbage	Set out	April 30 – May 16	3 wk before
🥕 Carrots	Direct sow	April 30 – May 16	3 wk before
🥬 Collards	Direct sow	April 30 – May 16	3 wk before
🥬 Collards	Set out	April 30 – May 16	3 wk before
🥒 Cucumbers	Start indoors	April 30 – May 16	3 wk before
🧅 Green Onions	Set out	April 30 – May 16	3 wk before
🥬 Kale	Direct sow	April 30 – May 16	3 wk before
🥬 Kale	Set out	April 30 – May 16	3 wk before
🥬 Kohlrabi	Direct sow	April 30 – May 16	3 wk before
🥬 Kohlrabi	Set out	April 30 – May 16	3 wk before
🥬 Leaf Lettuce	Direct sow	April 30 – May 16	3 wk before
🎃 Pumpkins	Start indoors	April 30 – May 16	3 wk before
🎃 Summer Squash	Start indoors	April 30 – May 16	3 wk before
🎃 Winter Squash	Start indoors	April 30 – May 16	3 wk before
🥒 Zucchini	Start indoors	April 30 – May 16	3 wk before
🥬 Bok Choy	Direct sow	May 7 – May 23	2 wk before
🥬 Bok Choy	Set out	May 7 – May 23	2 wk before
🥦 Broccoli	Set out	May 7 – May 23	2 wk before
🌿 Cilantro	Direct sow	May 7 – May 23	2 wk before
🥬 Leaf Lettuce	Set out	May 7 – May 23	2 wk before
🥬 Swiss Chard	Direct sow	May 7 – May 23	2 wk before
🥬 Swiss Chard	Set out	May 7 – May 23	2 wk before
🌿 Dill	Direct sow	May 14 – May 30	1 wk before
🫘 Bush Beans	Direct sow	May 28 – June 13	1 wk after
🥒 Cucumbers	Set out	May 28 – June 13	1 wk after
🎃 Pumpkins	Direct sow	May 28 – June 13	1 wk after
🎃 Pumpkins	Set out	May 28 – June 13	1 wk after
🎃 Summer Squash	Direct sow	May 28 – June 13	1 wk after
🎃 Summer Squash	Set out	May 28 – June 13	1 wk after
🌽 Sweet Corn	Direct sow	May 28 – June 13	1 wk after
🍅 Tomatoes	Set out	May 28 – June 13	1 wk after
🎃 Winter Squash	Direct sow	May 28 – June 13	1 wk after
🎃 Winter Squash	Set out	May 28 – June 13	1 wk after
🥒 Zucchini	Direct sow	May 28 – June 13	1 wk after
🥒 Zucchini	Set out	May 28 – June 13	1 wk after
🥒 Cucumbers	Direct sow	June 4 – June 20	2 wk after
🌶️ Okra	Direct sow	June 4 – June 20	2 wk after
🌶️ Okra	Set out	June 4 – June 20	2 wk after
🌶️ Peppers	Set out	June 4 – June 20	2 wk after
🫘 Southern Peas	Direct sow	June 4 – June 20	2 wk after
🍠 Sweet Potato	Set out	June 4 – June 20	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 lives through a zone 6a winter

Of 74 perennial edibles, 51 come through a zone 6a winter — and 0 fail here for being too warm rather than too cold, needing more winter chill than this county gets or more heat than they tolerate. Among the ones that work: Cranberry, Honeyberry, Lingonberry, Apple, Aronia, Black Currant, Elderberry, Gooseberry.

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 June 26 to be careful. Median May 21 – June 6 across 5 stations; May 4 is the optimistic end.
First fall freeze: Plan to September 5 to be careful. Median September 21 – September 26 across 5 stations; October 9 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 5 stations behind these numbers

All 5 NOAA stations whose normals this page quotes, spanning about 82 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
Fremont Indian SP, UT	USC00423012	June 4	September 21	106 days
Koosharem, UT	USC00424764	June 6	September 21	104 days
Richfield Radio Ksvc, UT	USC00427260	May 21	September 24	125 days
Salina 24 E, UT	USC00427559	May 29	September 26	118 days
Scipio, UT	USC00427714	May 22	September 25	122 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

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

More of Utah

Counties with the same zones — 6a

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 6a 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 6a, 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.