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Soil Table 3: Mean Earth Temperatures,
Annual Soil Swing, and Phase Constants for U.S. Cities*

Note: The 'Phase Constant' represents the coldest day of the year.
The warmest day of the year is approximately 6 months (180 days) after To.



State

City

Tm (oC)

As(oC)

To(Days)

 

 

 

 

 

AL

Birmingham

18.3

10.6

31

 

Montgomery

19.4

10.0

31

 

 

 

 

 

AZ

Phoenix

22.8

12.8

33

 

Tucson

21.1

10.0

34

 

 

 

 

 

AR

Little Rock

17.8

11.7

32

 

 

 

 

 

CA

Los Angeles

17.8

3.9

54

 

Merced

20.0

13.9

33

 

San Diego

17.8

3.9

54

 

 

 

 

 

CO

Colorado Springs

10.6

11.7

36

 

Denver

11.1

12.2

37

 

Grand Junction

12.8

13.9

32

 

 

 

 

 

DC

Washington

13.9

12.2

36

 

 

 

 

 

FL

Appalachico.

21.1

8.3

36

 

Jacksonville

21.7

7.8

32

 

 

 

 

 

GA

Atlanta

16.7

10.6

32

 

Augusta

18.3

10.0

30

 

Macon

19.4

9.4

33

 

 

 

 

 

ID

Boise

11.7

11.7

34

 

Idaho Falls

7.8

12.8

34

 

 

 

 

 

IL

Chicago

10.6

13.9

37

 

E. St. Louis

13.9

13.3

34

 

Urbana

11.7

14.4

35

 

 

 

 

 

State

City

Tm (oC)

As(oC)

To(Days)

 

 

 

 

 

IN

Fort Wayne

11.7

13.3

35

 

Indianapolis

12.8

13.3

34

 

South Bend

11.1

13.9

37

 

 

 

 

 

IA

Des Moines

11.1

15.6

35

 

Sioux City

10.6

16.1

34

 

 

 

 

 

KS

Dodge City

13.9

13.9

35

 

Topeka

13.3

14.4

35

 

 

 

 

 

KY

Louisville

15.6

12.2

33

 

 

 

 

 

LA

Lake Charles

21.1

8.9

32

 

New Orleans

21.1

8.3

32

 

Shreveport

18.9

10.6

32

 

 

 

 

 

MA

Portland

8.9

12.2

39

 

 

 

 

 

MS

Plymouth

10.6

11.7

43

 

 

 

 

 

MI

Battle Creek

10.0

13.3

35

 

Detroit

10.0

13.9

39

 

Sau St. Marie

5.6

14.4

40

 

 

 

 

 

MN

Duluth

5.0

15.6

37

 

Int. Falls

3.9

17.2

34

 

Minneapolis

8.3

16.1

35

 

 

 

 

 

MS

Biloxi

21.1

9.4

32

 

Columbus

18.3

10.6

32

 

Jackson

19.4

10.0

31

 

 

 

 

 

MO

Columbia

13.9

13.3

35

 

Kansas City

14.4

14.4

35

 

Springfield

14.4

12.8

34

 

 

 

 

 

State

City

Tm (oC)

As(oC)

To(Days)

 

 

 

 

 

MT

Billings

9.4

12.8

37

 

Great Falls

8.9

12.8

36

 

Missoula

7.8

11.7

32

 

 

 

 

 

NB

Grand Junction

11.1

15.0

35

 

Lincoln

11.7

15.6

34

 

N. Platte

10.6

14.4

35

 

 

 

 

 

NV

Ely

8.3

12.2

35

 

Las Vegas

20.6

12.8

32

 

Winnemucca

11.1

12.2

33

 

 

 

 

 

NJ

Trenton

12.8

12.2

38

 

 

 

 

 

NM

Albuquerque

15.0

12.2

31

 

Roswell

17.2

12.2

30

 

 

 

 

 

NY

Albany

10.0

13.9

38

 

Binghamton

8.9

13.3

38

 

Niagara Falls

10.0

13.3

24

 

Syracuse

10.0

13.3

38

 

 

 

 

 

NC

New Bern

18.3

9.4

35

 

Greensboro

15.6

11.1

31

 

 

 

 

 

ND

Bismark

6.7

17.2

33

 

Grand Forks

5.6

18.3

35

 

Williston

7.2

16.1

34

 

 

 

 

 

OH

Akron

11.1

12.8

37

 

Columbus

12.8

12.2

34

 

Dayton

13.3

13.3

35

 

Toledo

10.6

13.9

36

 

 

 

 

 

State

City

Tm (oC)

As(oC)

To(Days)

 

 

 

 

 

OK

Altus

18.3

13.3

33

 

Oklahoma City

16.7

12.8

34

 

Tulsa

16.7

12.8

34

 

 

 

 

 

OR

Astoria

11.7

5.0

45

 

Medford

12.8

9.4

34

 

Portland

12.2

7.2

37

 

 

 

 

 

PA

Middletown

12.8

12.8

35

 

Philadelphia

12.8

12.2

34

 

Pittsburg

11.1

12.8

36

 

Wilkes-Barre

11.1

12.8

36

 

 

 

 

 

SC

Charleston

18.9

8.9

32

 

Greenville

16.7

10.6

33

 

Sumpter

18.3

10.0

32

 

 

 

 

 

SD

Huron

8.3

16.7

35

 

Rapid City

10.0

13.9

38

 

 

 

 

 

TN

Bristol

15.0

11.1

32

 

Knoxville

16.1

11.7

31

 

Memphis

17.2

11.7

32

 

Nashville

15.6

11.7

32

 

 

 

 

 

TX

El Paso

18.9

11.1

28

 

Ft. Worth

20.0

11.7

34

 

Houston

21.7

8.9

33

 

San Antonio

22.2

8.9

32

 

 

 

 

 

UT

Salt Lake City

11.7

13.3

35

 

 

 

 

 

VT

Burlington

7.8

14.4

37

 

 

 

 

 

State

City

Tm (oC)

As(oC)

To(Days)

 

 

 

 

 

VA

Norfolk

16.1

11.1

37

 

Richmond

15.6

10.6

33

 

Roanoke

15.0

11.1

33

 

 

 

 

 

WA

Moses Lake

11.7

12.8

29

 

Seattle

11.7

6.7

36

 

Spokane

9.4

11.7

32

 

 

 

 

 

WV

Charleston

14.4

11.1

33

 

Elkins

11.1

11.1

32

 

 

 

 

 

WI

Green Bay

7.8

14.4

37

 

Madison

9.4

15.0

36

 

 

 

 

 

WY

Casper

9.4

13.3

37

 

Cheyenne

8.9

11.7

39

 

Lander

7.8

13.3

38

 

Sheridan

8.9

13.3

35



*Adapted from Closed-Loop/Ground-Source Heat Pump Systems Installation Guide.  NRECA Research Project 86-1.  Oklahoma State University.  1988. and Perry, Robert H. and Chilton, Cecil H. Chemical Engineer's Handbook. 5th Ed. New York, McGraw Hill Book Company, 1973.


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