CAMELOT CLIMATE INDEX
based on 1981-2010 Normals

Jan Null, CCM
 Golden Gate Weather Services

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CAMELOT

It's true!  It's true!
The crown has made it clear:
The climate must be perfect all the year.

A law was made a distant moon ago here,
June, July and August cannot be too hot;
And there's a legal limit to the snow here...
In Camelot.

The winter is forbidden till December...
And exits March the second on the dot.
By order summer lingers through September...
In Camelot.

I know it sounds a bit bizarre.
But in Camelot, Camelot,
That's how conditions are.

The rain may never fall till after sundown,
By eight the morning fog must disappear.
In short, there's simply not,
A more congenial spot
for happy everaftering than here
In Camelot.

~Alan Jay Lerner (1960)

Camelot Climate Index (see description below)

City State INDEX   MIN >90 <32 PCPN >.01 SNOW SUN THI
San Diego  CA 89   0 3 0 11 37 0 68 0
San Francisco C.O.  CA 87   0 2 0 22 67 0 66 0
Los Angeles C.O.  CA 86 0 23 0 15 33 0 73 3
Sacramento  CA 80   5 74 14 18 58 0 78 4
Eureka  CA 79   6 0 4 38 114 0 51 0
Las Vegas  NV 78   4 133 25 4 19 1 85 4
Fresno  CA 78   5 109 17 11 43 0 79 4
Redding  CA 76   8 98 28 34 76 4 88 4
Galveston  TX 76   0 12 4 44 97 0 62 6
Key West  FL 76   0 50 0 39 103 0 76 8
Tucson  AZ 76   3 153 15 12 44 1 85 4
El Paso  TX 76   9 102 57 9 42 6 84 4
Yuma  AZ 75   0 176 2 3 16 0 90 8
Honolulu HI 75   0 34 0 18 89 0 71 12
Kahului  HI 75   0 27 0 19 88 0 67 12
Phoenix  AZ 75   2 184 4 8 28 0 85 5
Seattle Sea-Tac Ap  WA 74   6 3 29 37 150 11 47 0
Apalachicola  FL 73   1 27 6 57 105 0 67 7
Cape Hatteras  NC 73   4 7 28 58 114 2 60 4
Lihue  HI 73   0 0 0 40 193 0 59 9
Portland  OR 72   10 13 39 37 147 7 48 0
Albuquerque  NM 72   17 61 111 9 53 11 76 3
Tampa  FL 71   0 87 2 45 100 0 66 6
Midland-Odessa  TX 71   11 100 60 15 45 5 74 5
Norfolk  VA 70   9 31 55 46 111 8 60 3
Atlanta  GA 70   7 35 46 50 108 2 60 4
Miami  FL 70   0 62 0 59 126 0 70 9
Roswell  NM 70   14 95 85 13 48 12 74 4
Charleston Ap SC 70   3 57 32 52 106 1 63 5
Jacksonville  FL 70   3 79 12 52 109 0 63 5
Abilene  TX 69   9 93 53 24 59 5 71 6
Lake Charles  LA 69   3 76 12 57 98 0 72 8
Reno  NV 69   23 58 153 7 46 25 79 2
Savannah  GA 69   3 69 28 50 105 0 62 5
Wilmington  NC 69   4 44 44 57 111 2 63 5
Charlotte  NC 69   11 43 62 44 104 6 62 4
Boise  ID 69   17 48 119 12 82 21 64 2
New York C.Park  NY 68   12 18 78 50 116 29 58 2
Grand Junction  CO 68   17 63 137 9 65 24 71 2
Pensacola  FL 68   2 67 14 64 104 0 60 5
Lubbock  TX 68   13 82 91 19 57 10 72 5
Greensboro-Wnstn-Salm NC 68   11 31 80 43 110 9 60 3
Amarillo  TX 68   17 65 113 20 64 17 73 4
Oklahoma City  OK 68   11 68 70 36 77 10 68 5
Washington Nat'L Ap DC 68   11 39 66 39 105 20 56 3
Boston  MA 68   14 13 92 43 120 43 58 2
Macon  GA 68   7 80 46 45 102 1 66 5
Asheville  NC 68   15 9 98 47 120 16 59 2
Greenville-Spartanburg  SC 68   11 40 61 50 109 7 60 4
Salt Lake City  UT 67   17 55 118 17 85 58 66 2
Philadelphia  PA 67   12 24 90 42 111 22 56 2
Cheyenne  WY 67   24 13 165 15 93 57 66 0
Richmond  VA 67   11 46 84 44 108 14 63 3
Spokane  WA 67   18 20 133 17 107 49 55 0
Columbia  SC 67   7 71 53 48 103 2 64 5
Denver  CO 67   20 33 152 16 82 60 69 2
Lynchburg  VA 67   15 24 94 43 111 19 59 3
Raleigh  NC 67   11 42 73 43 109 8 58 4
Knoxville  TN 66   11 29 72 48 121 12 56 4
Dallas-Fort Worth  TX 66   5 98 37 35 72 3 61 7
Louisville  KY 66   11 31 85 45 118 17 56 3
Atlantic City Ap  NJ 66   15 18 111 41 107 17 56 2
Pueblo  CO 66   21 72 158 12 65 32 76 2
Austin/City  TX 66   3 109 16 34 78 1 60 8
Flagstaff  AZ 66   26 6 210 23 78 101 78 0
Memphis  TN 66   9 66 56 55 99 5 64 5
Billings  MT 66   20 31 146 15 92 57 60 1
Harrisburg  PA 66   15 23 106 41 126 34 58 2
Brownsville  TX 66   0 136 3 28 66 0 60 9
Great Falls  MT 66   25 20 163 15 96 60 61 0
Shreveport  LA 65   3 89 36 51 92 2 63 7
Corpus Christi  TX 65   0 118 6 32 72 0 60 10
Providence  RI 65   15 11 118 46 118 36 58 2
Dodge City  KS 65   17 68 127 22 72 20 70 4
Ely  NV 65   28 19 218 10 68 51 73 0
Birmingham Ap AL 65   7 60 53 54 111 2 58 5
Concordia  KS 65   17 49 126 28 83 22 67 4
Lander  WY 65   26 21 186 13 66 101 68 0
Nashville  TN 65   11 49 69 48 112 10 56 4
New Orleans  LA 65   1 73 10 64 107 0 57 8
Fort Wayne  IN 65   17 12 126 37 126 33 59 3
Wichita  KS 65   16 63 109 30 80 16 65 4
Paducah KY 65   11 47 82 49 103 11 58 4
Baltimore  MD 65   17 33 98 42 107 22 57 3
St. Louis  MO 65   11 44 94 39 105 20 57 4
Pocatello  ID 65   23 35 170 13 88 42 64 1
Chattanooga  TN 65   11 53 66 55 113 4 57 4
Port Arthur  TX 65   2 83 13 60 97 0 58 8
Springfield  IL 64   17 31 117 36 107 23 59 3
Omaha (North)  NE 64   18 24 136 30 102 31 60 3
Helena  MT 64   25 20 180 11 89 46 59 0
Dayton  OH 64   17 15 118 40 126 28 53 2
Little Rock  AR 64   11 72 58 51 99 5 62 6
Montgomery  AL 64   4 76 40 55 100 0 59 7
Sioux City  IA 64   19 25 146 26 94 33 61 3
Evansville  IN 64   13 45 97 44 110 14 59 4
Kansas City  MO 64   16 41 110 38 97 20 60 4
Indianapolis  IN 64   17 14 116 41 120 25 55 3
San Antonio  TX 64   3 120 21 33 76 1 60 9
Milwaukee  WI 64   18 9 131 35 119 49 54 2
Springfield  MO 64   14 44 100 45 105 18 60 4
Detroit  MI 64   17 13 129 33 128 43 53 2
Minneapolis-St.Paul  MN 64   20 14 148 29 108 50 58 2
Tupelo  MS 64   11 72 53 56 104 3 64 7
Peoria  IL 64   18 22 127 36 108 26 56 3
Lincoln  NE 63   18 43 139 28 87 29 61 3
Des Moines  IA 63   18 24 137 35 102 35 59 3
Cleveland  OH 63   17 9 118 39 152 60 49 1
Chicago IL 63   18 19 127 36 119 39 54 2
Jackson  MS 63   6 81 49 56 102 1 61 7
Fort Smith  AR 63   11 71 68 44 91 6 61 7
Avoca  PA 63   17 10 123 38 134 48 51 2
Columbus  OH 63   17 13 110 39 132 29 50 3
Tulsa  OK 63   11 72 72 42 85 13 62 7
Toledo  OH 63   17 13 135 33 129 38 52 2
Topeka  KS 63   17 48 119 36 91 21 61 4
Portland  ME 63   21 5 149 46 123 71 57 0
Rapid City  SD 63   24 36 171 17 89 41 63 2
Greater Cincinnati Ap OH 63   15 20 108 43 125 24 50 3
Green Bay  WI 63   23 7 156 29 116 50 54 1
Houston  TX 63   3 100 17 48 98 0 59 10
Albany  NY 63   18 10 139 39 130 64 53 1
Buffalo  NY 63   17 4 126 41 163 94 48 0
Columbia  MO 63   17 39 106 40 106 23 56 4
Winnemucca  NV 63   23 64 186 8 64 24 68 2
Rochester  NY 62   17 9 131 34 156 94 51 1
North Platte  NE 62   24 40 175 20 77 31 67 3
Allentown  PA 62   17 17 127 45 119 33 53 2
Hartford  CT 62   17 19 130 46 122 50 56 2
Pittsburgh  PA 62   17 9 115 38 145 44 45 2
Lansing  MI 62   21 9 148 32 133 49 51 1
Moline  IL 62   18 26 131 38 108 32 55 3
Huron  SD 62   24 31 169 21 86 41 63 3
Valentine  NE 62   25 40 175 20 78 33 65 3
Binghamton  NY 62   18 3 142 39 156 85 49 0
Sheridan  WY 62   26 31 190 15 99 71 63 1
Blue Hill  MA 61   17 8 137 51 128 61 52 1
Madison  WI 61   19 13 158 33 115 51 54 2
Fargo  ND 61   24 15 180 21 97 42 57 2
Missoula  MT 61   23 21 193 14 117 46 55 0
Williston  ND 61   27 25 191 14 89 43 61 2
Bismarck  ND 61   26 24 188 17 90 45 59 2
Grand Rapids  MI 61   17 10 140 37 139 75 46 1
Burlington  VT 60   21 6 149 36 149 80 49 1
Alpena  MI 60   22 7 173 28 139 85 48 0
Duluth  MN 60   26 3 184 31 128 82 52 0
Concord  NH 59   22 14 174 38 122 65 54 1
Syracuse  NY 59   20 10 133 40 165 119 46 1
Quillayute  WA 59   12 0 62 102 202 13 33 0
Sault Ste. Marie  MI 58   24 3 174 35 160 117 47 0
Anchorage  AK 57   26 15 188 16 107 73 41 0
Elkins  WV 56   20 3 146 46 164 78 40 2
Hilo  HI 54   0 0 0 126 271 0 41 12
Nome  AK 53   32 7 236 17 124 66 42 0
Juneau  AK 51   21 26 139 58 218 99 30 0
Mt. Washington  NH 36   35 0 236 102 204 260 33 0

CAMELOT CLIMATE INDEX

In this 1960's musical King Arthur professes that Camelot has a perfect climate all the year; and by royal decree at that! But actually an "ideal" climate is extremely subjective, with one person's idea of perfection being met with disdain by others. Some individuals may want warm beach weather all year round, while four distinct seasons are most desirable for others. What follows is just one person's (the author's) idea that an ideal climate is sunny and relatively mild with few extremes in temperature, humidity or precipitation.

Dataset
Data for this project was extracted from the Comparative Climatic Data for the United States (NCDC, 2010) and updated 1981-2010 Normals (2011). Nine different weather elements were used in constructing an index of ideal weather; a Camelot Climate Index (CCI). These parameters are: maximum temperatures, minimum temperatures, mean number of days with minimum temperatures less than 32º F, mean number of days with maximum temperatures greater than 90º F, mean annual rainfall, mean number of days with precipitation, mean annual snowfall, average percent of sunshine, and average relative humidity. The average monthly maximum temperature and corresponding afternoon relative humidity were combined to derive a monthly temperature humidity index (THI) which is a measure of "discomfort".

The initial Comparative Climatic Data (CCC) analyzed has approximately 300 locations from all fifty states, Puerto Rico and 10 Pacific island stations.  This represents ninety major urban areas by stations within thirty miles. Unfortunately, not all of the meteorological parameters are available for all of the stations. In particular, some stations do not regularly record relative humidity and sunshine. The most limiting factor was the lack of data for the percent of possible sunshine data, with only 158 stations having all the requisite parameters.

Maximum Temperature
Because of the strong relationship between discomfort due to high temperature and high humidity, it was decided combine these factors using the temperature-humidity index (THI) using THI = Td-(0.55-0.55RH)(Td-58) where Td is the dry bulb temperature and RH is the relative humidity. A THI value was calculated for each month using the average maximum temperature and the average afternoon relative humidity. If the monthly THI was less than 75 degrees, then a value of 0 was assigned to the month. This threshold was chosen because statistically at least half of people feel uncomfortable with a THI greater than 75. If the THI was between 75 and 85 it was given a value of 1, between 85 and 95 a 2, between 95 and 105 a 3 and if it was 105 or greater a value of 4 was assigned to that month. The assigned monthly values were then summed to get an annual Temperature Humidity Index (THI). Additionally, the average annual number of days when the maximum was above 90 degrees (MAX90).

Minimum Temperature
The average monthly minimum temperatures were handled similarly. If the monthly minimum (MIN) was greater than 45 degrees, then a value of 0 was assigned to the month. If the monthly minimum was between 45 and 35 it was given a 1, between 35 and 25 a 2, between 25 and 15 a 3 and if it was 15 or less a value of 4 was assigned to that month. The assigned monthly values were then summed to get an annual minimum value (MIN). Data was also used for the average annual number of days when the minimum was below 32 degrees (MIN32).

Precipitation Data
The precipitation data set included several types of data. The annual average rainfall (RAIN) for each station was the primary data. Also the average number of days when measurable rain (i.e., greater than or equal to .01 inch) fell was used (RAIN01). The final precipitation parameter was the annual average snowfall expressed inches (SNOW).

Sunshine Data
The final data subset used was the annual percentage of possible sunshine (SUN). These values are derived by calculating the total time that sunshine reaches the station as a percentage of the maximum amount of possible from sunrise to sunset.

Index Calculation
Equal weight was given to each of the data categories in calculating the Camelot Climate Index (CCI). Thus the combination of maximum temperature, minimum temperature, precipitation and sunshine each account for 25% of the total index. Within the maximum temperature category, The THI was weighted as 10% and MAX90 as 15% of the total CCI. The minimum temperature group was weighted with MIN32 as 20% and MIN as 5%. In the precipitation group RAIN was weighted as 15%, RAIN32 as 5% and SNOW as 5%.

The maximum value for each category was used to set the "best possible" for that category. This was divided by the weight given that parameter to derive an overall rating factor. For example: the highest value of MAX90 was 170 days (at Yuma, AZ), and MAX90 has a weight of 15%, giving a weighting factor of 11.3, which is expressed as MAX90wf. The only exception to this was with the sunshine data, where the "ideal" condition would be 100% sunshine, thus the percent of sunshine received is subtracted from 100 initially, then divided by the given weight.

The total CCI for each station was derived by subtracting the weighted value for each parameter from a value of 100, which would be "perfect" weather. It takes the form: 
CCI=100-(THI/THIwf)-(MAX90/MAX90wf)-(MIN/MINwf)-
(MIN32/MIN32wf)-(RAIN/RAINwf)-(RAIN01/RAIN01wf)-
(SNOW/SNOWwf)-((100-SUN)/SUNwf)

CCI Map
The accompanying iso-analysis (isocams?) is rudimentary at best given the limited dataset.  Especially given the fact that no effort was made to draw for topography and there are undoubtedly areas, mostly in and around mountainous terrain, where an intermediate point would vary greatly from the rather crude analysis.

Conclusions
A project like this sort is by nature extremely subjective, as everyone's "ideal" climate is different. Even by quantifying a relatively small climatic dataset, numerous subjective choices had to be made, including which climatic factors to choose and how much weight to give to each.

And remember the primary assumptions for this study are based upon a 1960's musical about a mythical land with a mild dry "perfect" climate as expressed by mythical King Arthur! Consequently, cities with dry, mild and temperate climates ended up at the top of the Camelot Climate Indices.  If a similar project was done by a storm chaser it might be called the Oz Climate Index with a bias towards the number of thunderstorm days, hail and tornadoes.


Copyright © 2012, Golden Gate Weather Services. 
Reproduction in full or part is prohibited without permission.