What USDA hardiness zone is Wells County, North Dakota?

Every ZIP code in Wells County, North Dakota is USDA hardiness zone 4a, from the USDA 2023 Plant Hardiness Zone Map.

When is the last spring frost in Wells County, North Dakota?

The median last spring freeze runs May 10 – May 13 across the 4 NOAA weather stations serving Wells County, North Dakota, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

North Dakota

Planting zones in Wells County, North Dakota

Every ZIP code in this county is USDA zone 4a — 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 4a The same in all 7 ZIP codes

ZIP codes 7 7 have a NOAA station within range

Weather stations 4 NOAA 1991–2020 normals, across 1,271 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Wells County, North Dakota 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 Wells County is closing

Nothing in the 32-crop table still has time to mature here. The first fall freeze normally arrives September 26 – September 29 across the 4 NOAA stations serving this county .

Your next season already has a date

The first job of it is 🧅 Green Onions, start indoors, around March 15 – March 18 — counted back from a last spring freeze of May 10 – May 13 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 4 stations agreeAt least one station

Every one of the 4 NOAA stations serving this county counts May 13 – September 26 as growing season (136 days). Widening to any single station gives May 10 – September 29 (142 days).

Your freeze dates

Last spring freeze May 10 – May 13

First fall freeze September 26 – September 29

Across the 4 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 135–139 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 76.5–78.7 °F in June–August. Summer rain over the same months runs 8.2–9.1" across those 2 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 69% of it, so expect to make up the rest. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 78 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Wells 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
58341	4a	Harvey 4Ne, ND	4.5 km
58418	4a	Tuttle 12Nne, ND	25.0 km
58422	4a	Fessenden, ND	17.2 km
58423	4a	Tuttle 12Nne, ND	15.6 km
58438	4a	Fessenden, ND	4.7 km
58451	4a	Tuttle 12Nne, ND	17.0 km
58486	4a	Carrington, ND	20.5 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 Wells County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 4 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	March 15 – March 18	8 wk before
🌶️ Peppers	Start indoors	March 15 – March 18	8 wk before
🥦 Broccoli	Start indoors	March 29 – April 1	6 wk before
🥬 Cabbage	Start indoors	March 29 – April 1	6 wk before
🥬 Collards	Start indoors	March 29 – April 1	6 wk before
🥬 Kale	Start indoors	March 29 – April 1	6 wk before
🥬 Leaf Lettuce	Start indoors	March 29 – April 1	6 wk before
🫛 Peas	Direct sow	March 29 – April 1	6 wk before
🥬 Spinach	Direct sow	March 29 – April 1	6 wk before
🍠 Sweet Potato	Start indoors	March 29 – April 1	6 wk before
🍅 Tomatoes	Start indoors	March 29 – April 1	6 wk before
🥬 Bok Choy	Start indoors	April 5 – April 8	5 wk before
🥬 Kohlrabi	Start indoors	April 5 – April 8	5 wk before
🥬 Swiss Chard	Start indoors	April 5 – April 8	5 wk before
🥬 Arugula	Direct sow	April 12 – April 15	4 wk before
🥬 Baby Salad Greens	Direct sow	April 12 – April 15	4 wk before
🥕 Beets	Direct sow	April 12 – April 15	4 wk before
🧅 Green Onions	Direct sow	April 12 – April 15	4 wk before
🥬 Mustard Greens	Direct sow	April 12 – April 15	4 wk before
🌶️ Okra	Start indoors	April 12 – April 15	4 wk before
🌱 Radishes	Direct sow	April 12 – April 15	4 wk before
🥔 Turnips	Direct sow	April 12 – April 15	4 wk before
🥬 Cabbage	Set out	April 19 – April 22	3 wk before
🥕 Carrots	Direct sow	April 19 – April 22	3 wk before
🥬 Collards	Direct sow	April 19 – April 22	3 wk before
🥬 Collards	Set out	April 19 – April 22	3 wk before
🥒 Cucumbers	Start indoors	April 19 – April 22	3 wk before
🧅 Green Onions	Set out	April 19 – April 22	3 wk before
🥬 Kale	Direct sow	April 19 – April 22	3 wk before
🥬 Kale	Set out	April 19 – April 22	3 wk before
🥬 Kohlrabi	Direct sow	April 19 – April 22	3 wk before
🥬 Kohlrabi	Set out	April 19 – April 22	3 wk before
🥬 Leaf Lettuce	Direct sow	April 19 – April 22	3 wk before
🎃 Pumpkins	Start indoors	April 19 – April 22	3 wk before
🎃 Summer Squash	Start indoors	April 19 – April 22	3 wk before
🎃 Winter Squash	Start indoors	April 19 – April 22	3 wk before
🥒 Zucchini	Start indoors	April 19 – April 22	3 wk before
🥬 Bok Choy	Direct sow	April 26 – April 29	2 wk before
🥬 Bok Choy	Set out	April 26 – April 29	2 wk before
🥦 Broccoli	Set out	April 26 – April 29	2 wk before
🌿 Cilantro	Direct sow	April 26 – April 29	2 wk before
🥬 Leaf Lettuce	Set out	April 26 – April 29	2 wk before
🥬 Swiss Chard	Direct sow	April 26 – April 29	2 wk before
🥬 Swiss Chard	Set out	April 26 – April 29	2 wk before
🌿 Dill	Direct sow	May 3 – May 6	1 wk before
🫘 Bush Beans	Direct sow	May 17 – May 20	1 wk after
🥒 Cucumbers	Set out	May 17 – May 20	1 wk after
🎃 Pumpkins	Direct sow	May 17 – May 20	1 wk after
🎃 Pumpkins	Set out	May 17 – May 20	1 wk after
🎃 Summer Squash	Direct sow	May 17 – May 20	1 wk after
🎃 Summer Squash	Set out	May 17 – May 20	1 wk after
🌽 Sweet Corn	Direct sow	May 17 – May 20	1 wk after
🍅 Tomatoes	Set out	May 17 – May 20	1 wk after
🎃 Winter Squash	Direct sow	May 17 – May 20	1 wk after
🎃 Winter Squash	Set out	May 17 – May 20	1 wk after
🥒 Zucchini	Direct sow	May 17 – May 20	1 wk after
🥒 Zucchini	Set out	May 17 – May 20	1 wk after
🥒 Cucumbers	Direct sow	May 24 – May 27	2 wk after
🌶️ Okra	Direct sow	May 24 – May 27	2 wk after
🌶️ Okra	Set out	May 24 – May 27	2 wk after
🌶️ Peppers	Set out	May 24 – May 27	2 wk after
🫘 Southern Peas	Direct sow	May 24 – May 27	2 wk after
🍠 Sweet Potato	Set out	May 24 – May 27	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 4a winter

Of 74 perennial edibles, 34 come through a zone 4a 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 May 28 to be careful. Median May 10 – May 13 across 4 stations; April 28 is the optimistic end.
First fall freeze: Plan to September 14 to be careful. Median September 26 – September 29 across 4 stations; October 11 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 4 stations behind these numbers

All 4 NOAA stations whose normals this page quotes, spanning about 56 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
Carrington, ND	USC00321360	May 10	September 28	139 days
Fessenden, ND	USC00322949	May 13	September 28	139 days
Harvey 4Ne, ND	USC00324013	May 12	September 26	135 days
Tuttle 12Nne, ND	USC00328853	May 13	September 29	139 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

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

More of North Dakota

Counties with the same zones — 4a

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 4a 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 4a, 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.