USDA Plant Hardiness Zone 3

Zone 3 covers winter lows from -40°F to -30°F, split into 3a (-40 to -35°F) and 3b (-35 to -30°F).

USDA Plant Hardiness Zone 3 is one of the coldest growing regions in the continental United States, defined by an average annual extreme minimum winter temperature of -40 to -30 degrees F. Gardeners here plan around deep, sustained cold and a short frost-free window, so cold hardiness is the single most important factor in choosing what to plant.

Climate and where it is found

Zone 3 covers the far northern tier of the country, including much of northern Minnesota, northern North Dakota, and northern Wisconsin, along with cold pockets of Montana, northern Maine, and higher elevations in the Rockies of Wyoming, Colorado, and Idaho. Winters are long and severe, with heavy snow cover that can actually protect roots and crowns from the worst temperature swings. Summers are warm but brief, and the frost-free growing season is short, commonly running about 90 to 120 days. Late spring frosts and early fall frosts are routine, so the usable window can feel even shorter in low-lying spots.

States most often in Zone 3

Based on locations in our database, these states have the most ZIP codes falling in Zone 3:

What grows in Zone 3

Plants that thrive in Zone 3 are those that tolerate deep cold and mature quickly during a compressed season. Reliable perennials include very cold-hardy fruit such as certain apples, plums, currants, and haskap, plus rhubarb, asparagus, and native or prairie-adapted flowers and shrubs. Cool-season vegetables do especially well because they handle light frost and shorter days, while short-season and early-maturing varieties of warm-season crops are the safest bet. Woody plants should be rated to Zone 3 or lower, and gardeners often rely on snow cover and mulch to help borderline perennials survive the winter.

• Cold-hardy apples, plums, and haskap (honeyberry)
• Currants, gooseberries, and hardy raspberries
• Rhubarb and asparagus
• Cool-season greens such as lettuce, spinach, and kale
• Root crops including carrots, beets, radishes, and turnips
• Peas, cabbage, and broccoli
• Potatoes and short-season bush beans
• Early-maturing determinate tomatoes started indoors

Gardening tips for Zone 3

Track your local last spring frost and first fall frost dates and count backward and forward from them, since the season is too short to waste. Start heat-loving crops indoors weeks ahead and choose varieties with the lowest days-to-maturity you can find so they ripen before fall frost returns. Season extension pays off here: use cold frames, row cover, low tunnels, or a hoop house to warm the soil earlier and protect plants on cold nights at both ends of the season. For perennials and young trees, apply a thick layer of organic mulch after the ground freezes and rely on consistent snow cover to insulate roots through the coldest stretches.

Sample locations in Zone 3

Open any location for its live weather, frost dates, and planting calendar:

Related tools

Hardiness zones tell you what survives winter. To decide when to plant, check your frost dates and planting calendar, and browse crops and growing guides for individual plants.

Zone boundaries follow the 2023 USDA Plant Hardiness Zone Map, which is based on 1991-2020 winter minimum temperatures. Local microclimates, elevation, and unusual winters can differ from the map. Page updated Aug 4, 2026.