USDA Hardiness Zones

Zone 1a

Below -60°F (-51°C)

Extremely cold continental climate with very short growing season and severe winters

Fairbanks, AK, Resolute, NU

Zone 1b

-60°F to -55°F (-51°C to -48°C)

Very cold continental climate with short growing season

Prudhoe Bay, AK, Barrow, AK

Zone 2a

-50°F to -45°F (-46°C to -43°C)

Cold continental climate with limited growing season and harsh winters

Unalakleet, AK, Dawson, YT

Zone 2b

-45°F to -40°F (-43°C to -40°C)

Cold continental climate with moderate growing season

McGrath, AK, Whitehorse, YT

Zone 3a

-40°F to -35°F (-40°C to -37°C)

Cold climate with cool summers and cold winters, suitable for hardy crops

International Falls, MN, Duluth, MN, Fargo, ND

Zone 3b

-35°F to -30°F (-37°C to -34°C)

Cold climate with distinct seasons and reliable snow cover

Bismarck, ND, Thunder Bay, ON, Marquette, MI

Zone 4a

-30°F to -25°F (-34°C to -32°C)

Cold temperate climate with warm summers and cold winters

Minneapolis, MN, Green Bay, WI, Boise, ID

Zone 4b

-25°F to -20°F (-32°C to -29°C)

Temperate climate with four distinct seasons

Portland, ME, Milwaukee, WI, Albuquerque, NM

Zone 5a

-20°F to -15°F (-29°C to -26°C)

Moderate continental climate with warm summers and cold winters

Des Moines, IA, Chicago, IL, Denver, CO

Zone 5b

-15°F to -10°F (-26°C to -23°C)

Temperate climate with reliable growing season

Boston, MA, Detroit, MI, Salt Lake City, UT

Zone 6a

-10°F to -5°F (-23°C to -21°C)

Moderate climate with warm summers and cool winters

St. Louis, MO, Columbus, OH, Lebanon, PA

Zone 6b

-5°F to 0°F (-21°C to -18°C)

Temperate climate with extended growing season

Kansas City, MO, New York, NY, Cincinnati, OH

Zone 7a

0°F to 5°F (-18°C to -15°C)

Moderate continental climate with mild winters and warm summers

Richmond, VA, Oklahoma City, OK, Memphis, TN

Zone 7b

5°F to 10°F (-15°C to -12°C)

Mild temperate climate with long growing season

Atlanta, GA, Little Rock, AR, Raleigh, NC

Zone 8a

10°F to 15°F (-12°C to -9°C)

Mild climate with short, cool winters and long, warm summers

Dallas, TX, Seattle, WA, Birmingham, AL

Zone 8b

15°F to 20°F (-9°C to -7°C)

Mild subtropical climate with minimal frost

Austin, TX, Savannah, GA, Charleston, SC

Zone 9a

20°F to 25°F (-7°C to -4°C)

Warm climate with very mild winters and hot summers

Houston, TX, Phoenix, AZ, Jacksonville, FL

Zone 9b

25°F to 30°F (-4°C to -1°C)

Subtropical climate with rare frost and year-round growing

Tampa, FL, Los Angeles, CA, San Diego, CA

Zone 10a

30°F to 35°F (-1°C to 2°C)

Tropical climate with warm winters and hot summers

Miami, FL, Naples, FL, San Juan, PR

Zone 10b

35°F to 40°F (2°C to 4°C)

Tropical climate with no frost and year-round agriculture

Key West, FL, Hilo, HI, Homestead, FL

Zone 11a

40°F to 45°F (4°C to 7°C)

Tropical climate with consistently warm temperatures

Honolulu, HI, Kailua-Kona, HI

Zone 11b

45°F to 50°F (7°C to 10°C)

Equatorial tropical climate with minimal temperature variation

Kahalui, HI, Lahaina, HI

Zone 12a

50°F to 55°F (10°C to 13°C)

Hot tropical climate with high humidity

Pago Pago, AS, Koror, PW

Zone 12b

55°F to 60°F (13°C to 16°C)

Equatorial climate with consistently hot temperatures

Majuro, MH, Palikir, FM

Zone 13a

60°F to 65°F (16°C to 18°C)

Very hot tropical climate with extreme heat

Agana, GU, Saipan, MP

Zone 13b

Above 65°F (18°C)

Extremely hot equatorial climate year-round

Koror, PW, Yap, FM