Updated
9/3/15
John Drake Services, Inc.
1427 E. 68th Street
Long Beach, CA 90805
voice line
(562) 423-4879
electricity from the sun by John Drake II | home
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Solar Insolation Chart
The following is courtesy of US Schott.
This chart shows solar insolation in kilowatt-hours per day in many US locations.
For simplicity, we call this figure "Sun Hours / Day".
To find average sun hours per day in your area (column 5) you can look at the maps
above or find the city you are located in or near to on the following chart.
If you want year-round autonomy (where you will have enough power for periods of
reduced sunlight due to inclement weather), use the lowest figure. If you want 100%
autonomy in the summer, use the highest figure.
State
|
City
|
High
|
Low
|
Avg.
|
|
State
|
City
|
High
|
Low
|
Avg.
|
AK
|
Fairbanks
|
5.87
|
2.12
|
3.99
|
|
MO
|
Columbia
|
5.5
|
3.97
|
4.73
|
AK
|
Matanuska
|
5.24
|
1.74
|
3.55
|
|
MO
|
St. Louis
|
4.87
|
3.24
|
4.38
|
Al
|
Montgomery
|
4.69
|
3.37
|
4.23
|
|
MS
|
Meridian
|
4.86
|
3.64
|
4.43
|
AR
|
Bethel
|
6.29
|
2.37
|
3.81
|
|
MT
|
Glasgow
|
5.97
|
4.09
|
5.15
|
AR
|
Little Rock
|
5.29
|
3.88
|
4.69
|
|
MT
|
Great Falls
|
5.70
|
3.66
|
4.93
|
AZ
|
Tucson
|
7.42
|
6.01
|
6.57
|
|
MT
|
Summit
|
5.17
|
2.36
|
3.99
|
AZ
|
Page
|
7.30
|
5.65
|
6.36
|
|
NM
|
Albuquerque
|
7.16
|
6.21
|
6.77
|
AZ
|
Phoenix
|
7.13
|
5.78
|
6.58
|
|
NB
|
Lincoln
|
5.40
|
4.38
|
4.79
|
CA
|
Santa Maria
|
6.52
|
5.42
|
5.94
|
|
NB
|
N. Omaha
|
5.28
|
4.26
|
4.90
|
CA
|
Riverside
|
6.35
|
5.35
|
5.87
|
|
NC
|
Cape Hatteras
|
5.81
|
4.69
|
5.31
|
CA
|
Davis
|
6.09
|
3.31
|
5.10
|
|
NC
|
Greensboro
|
5.05
|
4.00
|
4.71
|
CA
|
Fresno
|
6.19
|
3.42
|
5.38
|
|
ND
|
Bismark
|
5.48
|
3.97
|
5.01
|
CA
|
Los Angeles
|
6.14
|
5.03
|
5.62
|
|
NJ
|
Sea Brook
|
4.76
|
3.20
|
4.21
|
CA
|
Soda Springs
|
6.47
|
4.40
|
5.60
|
|
NV
|
Las Vegas
|
7.13
|
5.84
|
6.41
|
CA
|
La Jolla
|
5.24
|
4.29
|
4.77
|
|
NV
|
Ely
|
6.48
|
5.49
|
5.98
|
CA
|
Inyokern
|
8.7
|
6.87
|
7.66
|
|
NY
|
Binghampton
|
3.93
|
1.62
|
3.16
|
CO
|
Grandby
|
7.47
|
5.15
|
5.69
|
|
NY
|
Ithaca
|
4.57
|
2.29
|
3.79
|
CO
|
Grand Lake
|
5.86
|
3.56
|
5.08
|
|
NY
|
Schenetady
|
3.92
|
2.53
|
3.55
|
CO
|
Grand Junct.
|
6.34
|
5.23
|
5.85
|
|
NY
|
Rochester
|
4.22
|
1.58
|
3.31
|
CO
|
Boulder
|
5.72
|
4.44
|
4.87
|
|
NY
|
NY City
|
4.97
|
3.03
|
4.08
|
DC
|
Washington
|
4.69
|
3.37
|
4.23
|
|
OH
|
Columbus
|
5.26
|
2.66
|
4.15
|
FL
|
Apalachicola
|
5.98
|
4.92
|
5.49
|
|
OH
|
Cleveland
|
4.79
|
2.69
|
3.94
|
FL
|
Belie Is.
|
5.31
|
4.58
|
4.99
|
|
OK
|
Stillwater
|
5.52
|
4.22
|
4.99
|
FL
|
Miami
|
6.26
|
5.05
|
5.62
|
|
OK
|
Oklahoma City
|
6.26
|
4.98
|
5.59
|
FL
|
Gainesville
|
5.81
|
4.71
|
5.27
|
|
OR
|
Astoria
|
4.76
|
1.99
|
3.72
|
FL
|
Tampa
|
6.16
|
5.26
|
5.67
|
|
OR
|
Corvallis
|
5.71
|
1.90
|
4.03
|
GA
|
Atlanta
|
5.16
|
4.09
|
4.74
|
|
OR
|
Medford
|
5.84
|
2.02
|
4.51
|
GA
|
Griffin
|
5.41
|
4.26
|
4.99
|
|
PA
|
Pittsburg
|
4.19
|
1.45
|
3.28
|
HI
|
Honolulu
|
6.71
|
5.59
|
6.02
|
|
PA
|
State College
|
4.44
|
2.79
|
3.91
|
IA
|
Ames
|
4.80
|
3.73
|
4.40
|
|
RI
|
Newport
|
4.69
|
3.58
|
4.23
|
ID
|
Boise
|
5.83
|
3.33
|
4.92
|
|
SC
|
Charleston
|
5.72
|
4.23
|
5.06
|
ID
|
Twin Falls
|
5.42
|
3.42
|
4.70
|
|
SD
|
Rapid City
|
5.91
|
4.56
|
5.23
|
IL
|
Chicago
|
4.08
|
1.47
|
3.14
|
|
TN
|
Nashville
|
5.20
|
3.14
|
4.45
|
IN
|
Indianapolis
|
5.02
|
2.55
|
4.21
|
|
TN
|
Oak Ridge
|
5.06
|
3.22
|
4.37
|
KN
|
Manhattan
|
5.08
|
3.62
|
4.57
|
|
TX
|
San Antonio
|
5.88
|
4.65
|
5.30
|
KN
|
Dodge City
|
4.14
|
5.28
|
5.79
|
|
TX
|
Brownsville
|
5.49
|
4.42
|
4.92
|
KY
|
Lexington
|
5.97
|
3.60
|
4.94
|
|
TX
|
El Paso
|
7.42
|
5.87
|
6.72
|
LA
|
Lake Charles
|
5.73
|
4.29
|
4.93
|
|
TX
|
Midland
|
6.33
|
5.23
|
5.83
|
LA
|
New Orleans
|
5.71
|
3.63
|
4.92
|
|
TX
|
Fort Worth
|
6.00
|
4.80
|
5.43
|
LA
|
Shreveport
|
4.99
|
3.87
|
4.63
|
|
UT
|
Salt Lake City
|
6.09
|
3.78
|
5.26
|
MA
|
E. Wareham
|
4.48
|
3.06
|
3.99
|
|
UT
|
Flaming Gorge
|
6.63
|
5.48
|
5.83
|
MA
|
Boston
|
4.27
|
2.99
|
3.84
|
|
VA
|
Richmond
|
4.50
|
3.37
|
4.13
|
MA
|
Blue Hill
|
4.38
|
3.33
|
4.05
|
|
WA
|
Seattle
|
4.83
|
1.60
|
3.57
|
MA
|
Natick
|
4.62
|
3.09
|
4.10
|
|
WA
|
Richland
|
6.13
|
2.01
|
4.44
|
MA
|
Lynn
|
4.60
|
2.33
|
3.79
|
|
WA
|
Pullman
|
6.07
|
2.90
|
4.73
|
MD
|
Silver Hill
|
4.71
|
3.84
|
4.47
|
|
WA
|
Spokane
|
5.53
|
1.16
|
4.48
|
ME
|
Caribou
|
5.62
|
2.57
|
4.19
|
|
WA
|
Prosser
|
6.21
|
3.06
|
5.03
|
ME
|
Portland
|
5.23
|
3.56
|
4.51
|
|
WI
|
Madison
|
4.85
|
3.28
|
4.29
|
MI
|
Sault Ste. Marie
|
4.83
|
2.33
|
4.20
|
|
WV
|
Charleston
|
4.12
|
2.47
|
3.65
|
MI
|
E. Lansing
|
4.71
|
2.70
|
4.00
|
|
WY
|
Lander
|
6.81
|
5.50
|
6.06
|
MN
|
St. Cloud
|
5.43
|
3.53
|
4.53
|
|
|
||||