Claiborne West Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Claiborne West Park clear sky chart from 2005-11-05 to 2017-09-24.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
56%
15393
23%
46953
18%
15347
60%
15347
31%
28370

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
37%
900
23%
2327
11%
895
44%
895
28%
1578
January16th to endNight
37%
960
23%
2496
11%
960
43%
960
29%
1685
February1st to 15thNight
37%
842
24%
2251
11%
839
43%
839
29%
1463
February16th to endNight
35%
474
25%
1736
15%
474
46%
474
23%
1063
March1st to 15thNight
38%
540
23%
1980
17%
540
47%
540
22%
1226
March16th to endNight
48%
576
21%
2112
18%
576
54%
576
28%
1196
April1st to 15thNight
49%
539
23%
1878
19%
539
56%
539
27%
1098
April16th to endNight
47%
540
22%
1800
20%
540
53%
540
29%
1071
May1st to 15thNight
51%
539
17%
1800
18%
539
56%
539
26%
1112
May16th to endNight
67%
563
25%
1697
27%
561
71%
561
37%
969
June1st to 15thNight
84%
540
18%
1620
21%
540
84%
540
42%
869
June16th to endNight
77%
540
15%
1620
19%
540
77%
540
30%
1009
July1st to 15thNight
77%
510
16%
1530
19%
510
77%
510
34%
912
July16th to endNight
81%
564
15%
1594
18%
531
81%
531
35%
949
August1st to 15thNight
89%
539
22%
1680
26%
536
89%
536
47%
855
August16th to endNight
74%
573
13%
1910
16%
573
74%
573
23%
1242
September1st to 15thNight
76%
540
16%
1869
17%
540
76%
540
29%
1096
September16th to endNight
74%
519
27%
1914
32%
519
75%
519
29%
1075
October1st to 15thNight
75%
660
30%
1980
25%
660
76%
660
43%
1056
October16th to endNight
65%
704
35%
2112
28%
704
71%
704
45%
1106
November1st to 15thNight
59%
700
29%
2100
23%
700
62%
700
35%
1210
November16th to endNight
50%
720
33%
2160
24%
720
58%
720
37%
1234
December1st to 15thNight
42%
851
24%
2291
14%
851
47%
851
27%
1531
December16th to endNight
36%
960
19%
2496
10%
960
40%
960
24%
1765

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
12%6%36%6%35%5%6%7%35%
47971
Night
11%5%2442445%8%46%
47149
TransparencyDay
43%6%12%16%14%5%
47672
Night
35%5%14%19%16%8%
46953
SeeingDay
12%313%25%28%17%
5432
Night
13%419%30%26%5%
15394

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
17%5%25%5%23446%42%
1611
16th to endDay
20%7%24422335%41%
1728
February1st to 15thDay
18%8%35%433435%39%
1620
16th to endDay
21%8%35%42333439%
1738
March1st to 15thDay
23%7%24313346%37%
1980
16th to endDay
15%6%46%5%34445%40%
2110
April1st to 15thDay
14%6%36%5%35%45%8%37%
2068
16th to endDay
13%6%36%6%36%5%6%7%34%
2160
May1st to 15thDay
12%7%36%6%36%47%7%32%
2151
16th to endDay
8%5%37%7%47%7%7%10%31%
2415
June1st to 15thDay
5%5%28%7%5%8%7%7%9%30%
2340
16th to endDay
6%5%47%10%6%9%7%8%11%22%
2340
July1st to 15thDay
9%5%36%8%5%7%9%10%9%23%
2340
16th to endDay
8%5%37%9%6%9%9%7%9%23%
2466
August1st to 15thDay
4325%7%5%8%10%8%11%31%
2268
16th to endDay
11%5%26%9%5%8%8%7%8%25%
2292
September1st to 15thDay
10%5%37%7%36%6%6%8%33%
2088
16th to endDay
10%437%7%45%7%6%8%34%
1893
October1st to 15thDay
7%426%5%3445%7%49%
1650
16th to endDay
10%32442235%6%55%
1760
November1st to 15thDay
9%5%36%5%25%446%45%
1758
16th to endDay
13%6%25%423335%49%
1800
December1st to 15thDay
17%7%36%5%34446%36%
1667
16th to endDay
20%9%36%5%23336%35%
1728
January1st to 15thNight
18%6%35%423336%41%
2327
16th to endNight
19%6%25%423345%42%
2496
February1st to 15thNight
16%6%25%423346%44%
2242
16th to endNight
17%7%24423236%43%
1736
March1st to 15thNight
18%7%34422346%41%
1980
16th to endNight
12%6%24323447%48%
2112
April1st to 15thNight
13%5%2442446%8%43%
1878
16th to endNight
12%6%24434449%43%
1800
May1st to 15thNight
9%6%35%5%3446%10%41%
1799
16th to endNight
7%41332447%10%49%
1695
June1st to 15thNight
221342446%10%55%
1620
16th to endNight
5%324437%6%8%11%40%
1620
July1st to 15thNight
4334425%5%7%12%45%
1620
16th to endNight
3324425%6%8%14%44%
1702
August1st to 15thNight
2123246%7%12%54%
1690
16th to endNight
8%325%5%46%5%7%11%38%
1910
September1st to 15thNight
8%3245%35%5%7%10%43%
1869
16th to endNight
6%425%43445%8%49%
1914
October1st to 15thNight
6%21332345%8%57%
1980
16th to endNight
9%312312236%63%
2112
November1st to 15thNight
8%4145%245%5%6%51%
2100
16th to endNight
11%5%14423235%54%
2160
December1st to 15thNight
15%9%25%434446%39%
2291
16th to endNight
19%8%35%424445%37%
2496

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
41%47%16%20%10%
1612
16th to endDay
45%35%15%17%11%
1728
February1st to 15thDay
46%36%15%20%8%
1622
16th to endDay
47%48%13%18%8%
1738
March1st to 15thDay
47%48%14%18%7%
1980
16th to endDay
41%49%16%21%5%
2112
April1st to 15thDay
43%5%8%16%17%9%
2068
16th to endDay
45%6%12%14%14%6%
2160
May1st to 15thDay
45%6%13%14%13%6%
2151
16th to endDay
41%7%15%21%12%2
2419
June1st to 15thDay
43%7%15%18%13%1
2340
16th to endDay
48%9%17%17%7%
2340
July1st to 15thDay
45%11%20%17%5%
2201
16th to endDay
48%11%19%18%1
2311
August1st to 15thDay
37%11%21%23%6%
2254
16th to endDay
49%13%16%14%5%1
2292
September1st to 15thDay
45%8%15%15%11%3
2088
16th to endDay
43%6%11%17%15%5%
1893
October1st to 15thDay
31%411%20%17%14%
1650
16th to endDay
28%27%15%30%15%
1760
November1st to 15thDay
37%411%18%18%9%
1758
16th to endDay
36%35%14%24%13%
1800
December1st to 15thDay
46%49%17%13%7%
1667
16th to endDay
51%47%15%15%5%
1728
January1st to 15thNight
44%35%13%21%11%
2327
16th to endNight
43%36%16%17%12%
2496
February1st to 15thNight
41%27%14%21%11%
2251
16th to endNight
43%36%17%16%12%
1736
March1st to 15thNight
44%310%14%17%10%
1980
16th to endNight
35%5%14%16%21%7%
2112
April1st to 15thNight
37%411%19%16%10%
1878
16th to endNight
37%314%19%15%9%
1800
May1st to 15thNight
38%6%15%16%14%8%
1800
16th to endNight
28%7%15%29%15%3
1697
June1st to 15thNight
22%8%19%31%17%1
1620
16th to endNight
31%11%22%25%8%
1620
July1st to 15thNight
29%10%29%24%6%
1530
16th to endNight
27%11%33%24%3
1594
August1st to 15thNight
18%8%30%34%7%
1680
16th to endNight
37%12%25%16%7%1
1910
September1st to 15thNight
33%8%23%19%10%4
1869
16th to endNight
32%6%12%21%18%7%
1914
October1st to 15thNight
25%411%23%19%16%
1980
16th to endNight
25%36%16%29%19%
2112
November1st to 15thNight
31%5%10%20%23%8%
2100
16th to endNight
32%27%14%25%16%
2160
December1st to 15thNight
44%39%19%14%7%
2291
16th to endNight
48%46%14%15%9%
2496

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
21%341%22%12%
90
16th to endDay
16%13%38%21%8%1
96
February1st to 15thDay
17%11%36%28%5%
90
16th to endDay
11%12%44%24%7%
81
March1st to 15thDay
25%5%47%16%4
90
16th to endDay
19%10%20%34%12%2
96
April1st to 15thDay
14%10%21%35%17%
187
16th to endDay
20%420%30%21%2
270
May1st to 15thDay
14%5%18%38%19%3
288
16th to endDay
10%319%36%24%5%
502
June1st to 15thDay
9%8%31%35%14%
495
16th to endDay
9%17%23%36%20%
495
July1st to 15thDay
7%5%25%33%27%
475
16th to endDay
8%1317%35%33%
515
August1st to 15thDay
6%214%40%35%
421
16th to endDay
16%314%31%33%
332
September1st to 15thDay
8%1217%38%32%
243
16th to endDay
7%216%49%24%
114
October1st to 15thDay
216%44%28%16%
90
16th to endDay
16%314%31%21%12%
96
November1st to 15thDay
15%120%36%21%5%
90
16th to endDay
18%6%23%34%12%4
90
December1st to 15thDay
27%322%31%10%5%
90
16th to endDay
26%12%37%16%6%1
96
January1st to 15thNight
21%6%30%32%9%
900
16th to endNight
22%6%29%32%8%
960
February1st to 15thNight
18%8%32%32%7%
842
16th to endNight
20%6%33%34%4
474
March1st to 15thNight
20%6%29%36%7%
540
16th to endNight
14%427%37%15%
576
April1st to 15thNight
14%6%26%40%12%
539
16th to endNight
16%327%37%14%
540
May1st to 15thNight
12%326%42%14%
540
16th to endNight
8%216%38%31%3
563
June1st to 15thNight
3235%50%5%
540
16th to endNight
7%1325%48%13%
540
July1st to 15thNight
5%117%53%20%
510
16th to endNight
3115%54%24%
564
August1st to 15thNight
2113%62%20%
539
16th to endNight
10%114%54%17%
573
September1st to 15thNight
9%320%49%15%
540
16th to endNight
8%5%26%47%10%
519
October1st to 15thNight
6%11%32%43%5%
660
16th to endNight
11%314%35%31%4
704
November1st to 15thNight
11%320%36%25%3
700
16th to endNight
13%5%26%35%18%1
720
December1st to 15thNight
20%6%25%31%15%
851
16th to endNight
23%6%28%29%10%
960
Page generated at 2017-09-25 08:02:23. Version ac04

Copyright 2017 A. Danko


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