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USDA Plant Hardiness Zone Map

Hardiness Zones -- Details

Zone Color Key

  Zones 2-10 in the map have been subdivided into light- and dark-colored sections (a and b) that represent 5 F (2.8 C) differences within the 10 F (5.6 C) zone.  The light color of each zone represents the colder section; the dark color, the warmer section.  Zone 11 represents any area where the average annual minimum temperature is above 40 F (4.4 C). The map shows 20 latitude and longitude lines.  Areas above an arbitrary elevation are traditionally considered unsuitable for plant cropping and do not bear appropriate zone designations.  There are also island zones that, because of elevation differences, are warmer or cooler than the surrounding areas and are given a different zone designation.  Note that many large urban areas carry a warmer zone designation than the surrounding countryside.  The map-contains as much detail as possible, considering the vast amount of data on which it is based and its size.

USDA Hardiness Zones and Average Annual Minimum Temperature Range

  Zone  

  Fahrenheit  

    Celsius    

  Example Cities  

1

 Below -50 F  

Below -45.6 C

Fairbanks, Alaska;   Resolute, Northwest Territories (Canada) 

2a

-50 to -45 F  

-42.8 to -45.5 C

Prudhoe Bay, Alaska;   Flin Flon, Manitoba (Canada) 

2b

-45 to -40 F

-40.0 to -42.7 C

Unalakleet, Alaska;   Pinecreek, Minnesota 

3a

-40 to -35 F

-37.3 to -39.9 C

International Falls, Minnesota;   St. Michael, Alaska

3b

-35 to -30 F

-34.5 to -37.2 C

Tomahawk, Wisconsin;   Sidney, Montana

4a

-30 to -25 F

-31.7 to -34.4 C

Minneapolis/St.Paul, Minnesota;   Lewistown, Montana

4b

-25 to -20 F

-28.9 to -31.6 C

Northwood, Iowa; Nebraska

5a

-20 to -15 F

-26.2 to -28.8 C

Des Moines, Iowa;   Illinois

5b

-15 to -10 F

-23.4 to -26.1 C

Columbia, Missouri;   Mansfield, Pennsylvania

6a

-10 to -5 F

-20.6 to -23.3 C

St. Louis, Missouri; Lebanon, Pennsylvania

6b

-5 to 0 F  

-17.8 to -20.5 C

McMinnville, Tennessee;   Branson, Missouri 

7a

0 to 5 F

-15.0 to -17.7 C

Oklahoma City, Oklahoma;   South Boston, Virginia

7b

5 to 10 F

-12.3 to -14.9 C

Little Rock, Arkansas;   Griffin, Georgia

8a 

10 to 15 F

-9.5 to -12.2 C

Tifton, Georgia;   Dallas, Texas 

8b

15 to 20 F

-6.7 to -9.4 C

Austin, Texas;   Gainesville, Florida

9a

20 to 25 F

-3.9 to -6.6 C

Houston, Texas;   St. Augustine, Florida

9b

25 to 30 F

-1.2 to -3.8 C

Brownsville, Texas;   Fort Pierce, Florida

10a

30 to 35 F

1.6 to -1.1 C

Naples, Florida;   Victorville, California

10b

35 to 40 F

4.4 to 1.7 C

Miami, Florida;   Coral Gables, Florida

11

above 40 F

above 4.5 C

Honolulu, Hawaii;   Mazatlan, Mexico