Zone 4b

Hardiness Zone 4b

USDA hardiness zone 4b has an average coldest winter night of -25 to -20 °F (-32 to -29 °C). On the 2023 map it covers ZIP codes in 15 states, mostly Minnesota, Wisconsin and South Dakota. Cities in zone 4b include Saint Cloud, MN; Rochester, MN; Great Falls, MT.

Average coldest night

-25 to -20 °F

-32 to -29 °C

States with zone 4b

ZIP codes in zone 4b

1,284

Check your own zone

States in zone 4b

State	ZIP codes	Share of state
Minnesota	344	36%
Wisconsin	238	27%
South Dakota	183	48%
Montana	129	32%
New York	107	5%
Vermont	70	23%
Wyoming	43	22%
Michigan	38	3%
North Dakota	35	9%
Maine	30	6%
Alaska	28	10%
Iowa	17	2%
Colorado	10	2%
New Hampshire	10	4%
Idaho	2	1%

Cities in zone 4b

Larger places where every ZIP code is zone 4b.

Zones: 2023 USDA Plant Hardiness Zone Map ZIP code data, USDA Agricultural Research Service and the PRISM Climate Group, Oregon State University (official map). Place names: GeoNames (CC BY 4.0). Each ZIP code gets one zone, but a ZIP code can cross a zone line, and hills, valleys and towns can be warmer or colder than the zone shown.

About the Hardiness Zone Map

The Hardiness Zone Map finds your USDA plant hardiness zone, also called your planting or growing zone, from your ZIP code. Zones are based on the average coldest winter night of the year: each zone is 10 °F wide and split into a and b halves of 5 °F, from zone 1a in Alaska to 13b in Puerto Rico. Plant labels and seed packets give the coldest zone a plant can survive, so knowing your zone tells you which perennials, shrubs and trees can stay outside all winter. Zones come from the official 2023 USDA map ZIP code data for all 50 states, Washington DC and Puerto Rico.

How to use it

1 Enter your 5-digit ZIP code and press Find my zone.
2 Read your zone and the average coldest winter temperature it stands for.
3 Open your state to see its zones and the zone of every city.
4 Choose plants rated for your zone number or a colder (lower) one.

Frequently asked questions

What is the lowest temperature in zone 4b?

In zone 4b the coldest night of the year averages -25 to -20 °F (-32 to -29 °C). That is an average over 1991–2020, so a hard winter can go lower.

Which states have zone 4b?

Zone 4b is found in Minnesota, Wisconsin, South Dakota, Montana, New York, Vermont, Wyoming, Michigan, North Dakota, Maine, Alaska, Iowa, Colorado, New Hampshire and Idaho.

What is the difference between zone 4a and 4b?

Zone 4b is 5 °F warmer than 4a. Zone 4a has winter lows of -30 to -25 °F, and zone 4b -25 to -20 °F. Plant labels often give only the number, which covers both halves.

What plants grow in zone 4b?

Plants labelled hardy to zone 4 or colder (a lower number) should survive a zone 4b winter. Plants rated only for warmer zones may be damaged by frost unless grown in pots and brought in, or given shelter.

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