Fort Pickens
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Pickens clear sky chart from 2005-11-05 to 2017-09-16.

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
60%
15213
22%
46988
18%
15169
65%
15169
31%
28132

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
41%
720
22%
2204
12%
716
52%
716
27%
1372
January16th to endNight
37%
768
24%
2304
13%
768
47%
768
24%
1498
February1st to 15thNight
44%
703
28%
2107
16%
699
55%
699
32%
1259
February16th to endNight
41%
631
22%
1893
12%
631
49%
631
27%
1223
March1st to 15thNight
48%
720
22%
2160
13%
720
56%
720
31%
1304
March16th to endNight
60%
680
26%
2033
20%
680
65%
680
34%
1175
April1st to 15thNight
59%
539
25%
1797
23%
539
65%
539
33%
1000
April16th to endNight
68%
540
29%
1800
28%
540
73%
540
41%
914
May1st to 15thNight
69%
539
22%
1754
22%
539
72%
539
37%
939
May16th to endNight
75%
561
23%
1682
22%
561
76%
561
39%
949
June1st to 15thNight
76%
540
14%
1620
15%
540
76%
540
34%
947
June16th to endNight
79%
540
16%
1620
16%
540
80%
540
32%
979
July1st to 15thNight
81%
510
11%
1546
11%
510
81%
510
29%
975
July16th to endNight
78%
564
9%
1772
11%
531
78%
531
26%
1126
August1st to 15thNight
82%
539
10%
1788
13%
536
82%
536
28%
1097
August16th to endNight
68%
573
15%
1910
17%
573
68%
573
22%
1253
September1st to 15thNight
70%
613
16%
1873
16%
613
70%
613
27%
1212
September16th to endNight
68%
661
24%
1826
20%
661
70%
661
33%
1149
October1st to 15thNight
73%
660
32%
1815
28%
660
76%
660
44%
1026
October16th to endNight
63%
704
33%
2032
29%
704
67%
704
38%
1162
November1st to 15thNight
57%
700
30%
2276
27%
700
65%
700
37%
1231
November16th to endNight
53%
720
28%
2340
24%
720
61%
720
33%
1318
December1st to 15thNight
47%
720
24%
2340
19%
720
55%
720
28%
1403
December16th to endNight
43%
768
20%
2496
16%
768
49%
768
22%
1621

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
9%5%244345%6%9%44%
47737
Night
9%42442445%8%47%
47207
TransparencyDay
34%8%15%20%15%5%
47452
Night
33%7%14%19%17%7%
46996
SeeingDay
10%210%21%33%21%
5167
Night
11%316%25%30%12%
15217

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
10%425%5%25%35%8%45%
1731
16th to endDay
16%6%25%423445%44%
1920
February1st to 15thDay
12%6%24324447%48%
1750
16th to endDay
14%424324348%48%
1580
March1st to 15thDay
10%6%245%23448%47%
1800
16th to endDay
10%5%24434446%49%
2197
April1st to 15thDay
11%5%2442345%7%48%
2151
16th to endDay
6%31432436%8%55%
2160
May1st to 15thDay
6%3144345%5%8%51%
2193
16th to endDay
5%3234245%6%9%49%
2431
June1st to 15thDay
7%4245%36%7%9%12%37%
2340
16th to endDay
6%4245%45%6%8%13%36%
2340
July1st to 15thDay
6%5%25%6%5%7%8%10%14%26%
2319
16th to endDay
6%5%26%7%38%7%9%13%28%
2276
August1st to 15thDay
8%5%246%46%8%9%13%29%
2160
16th to endDay
11%5%35%5%35%6%7%10%35%
2292
September1st to 15thDay
10%5%25%4447%7%10%37%
2073
16th to endDay
6%4245%35%5%7%8%44%
1824
October1st to 15thDay
6%31331346%8%56%
1815
16th to endDay
8%44423245%58%
1835
November1st to 15thDay
8%413324447%55%
1582
16th to endDay
7%31443445%7%53%
1620
December1st to 15thDay
10%5%345%33447%46%
1620
16th to endDay
19%8%35%5%34346%35%
1728
January1st to 15thNight
12%6%23434446%46%
2204
16th to endNight
15%7%35%424346%43%
2304
February1st to 15thNight
13%5%22323346%51%
2103
16th to endNight
14%6%25%424345%46%
1893
March1st to 15thNight
10%5%25%42445%7%47%
2160
16th to endNight
10%314324448%51%
2033
April1st to 15thNight
9%4234245%47%50%
1797
16th to endNight
7%312324347%59%
1800
May1st to 15thNight
8%3143143410%54%
1754
16th to endNight
5%32342446%9%52%
1682
June1st to 15thNight
5%325%5%2447%12%45%
1620
16th to endNight
5%314325%7%9%13%42%
1620
July1st to 15thNight
42145%36%7%9%13%41%
1637
16th to endNight
43246%36%7%9%13%37%
1892
August1st to 15thNight
5%3145%35%6%10%14%39%
1800
16th to endNight
9%5%25%6%35%5%6%10%40%
1910
September1st to 15thNight
8%5%25%5%35%5%8%11%38%
1873
16th to endNight
9%424435%46%9%46%
1826
October1st to 15thNight
5%31332345%9%56%
1815
16th to endNight
9%323424336%56%
2032
November1st to 15thNight
8%5%24422347%55%
2276
16th to endNight
10%424323436%54%
2340
December1st to 15thNight
10%6%24424447%47%
2340
16th to endNight
15%7%35%43445%6%39%
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
36%5%10%17%23%7%
1732
16th to endDay
42%5%7%15%21%8%
1920
February1st to 15thDay
35%410%18%22%8%
1752
16th to endDay
35%6%9%19%21%7%
1580
March1st to 15thDay
35%5%10%22%20%5%
1800
16th to endDay
33%5%14%21%18%7%
2198
April1st to 15thDay
34%5%10%22%19%6%
2151
16th to endDay
25%6%14%26%19%6%
2160
May1st to 15thDay
27%7%16%22%18%7%
2193
16th to endDay
26%9%18%26%17%2
2435
June1st to 15thDay
31%11%20%27%7%
2340
16th to endDay
33%11%22%21%9%1
2340
July1st to 15thDay
39%18%24%14%3
2181
16th to endDay
39%15%25%16%3
2133
August1st to 15thDay
37%17%23%16%4
2148
16th to endDay
38%13%22%16%6%2
2292
September1st to 15thDay
36%11%20%17%10%3
2073
16th to endDay
33%10%14%18%17%5%
1824
October1st to 15thDay
24%6%13%20%21%13%
1815
16th to endDay
28%46%15%27%17%
1835
November1st to 15thDay
29%410%20%25%10%
1582
16th to endDay
28%6%10%21%19%13%
1620
December1st to 15thDay
35%6%12%21%19%4
1620
16th to endDay
49%5%9%19%12%4
1728
January1st to 15thNight
38%5%10%13%24%7%
2204
16th to endNight
43%47%14%22%8%
2304
February1st to 15thNight
34%47%18%23%11%
2112
16th to endNight
40%6%7%13%21%11%
1893
March1st to 15thNight
35%5%12%18%21%6%
2160
16th to endNight
30%5%9%24%19%10%
2033
April1st to 15thNight
31%5%13%17%23%9%
1797
16th to endNight
24%411%30%21%7%
1800
May1st to 15thNight
27%5%15%22%21%7%
1755
16th to endNight
25%8%19%22%20%3
1684
June1st to 15thNight
28%9%25%23%11%
1620
16th to endNight
27%13%24%23%10%
1620
July1st to 15thNight
27%16%31%18%5%
1546
16th to endNight
31%15%30%18%3
1772
August1st to 15thNight
29%14%33%19%3
1788
16th to endNight
38%12%21%19%5%2
1910
September1st to 15thNight
36%9%21%16%12%3
1873
16th to endNight
33%8%16%18%17%5%
1826
October1st to 15thNight
25%6%9%23%20%15%
1815
16th to endNight
30%36%14%25%18%
2032
November1st to 15thNight
30%37%20%27%10%
2276
16th to endNight
31%48%17%21%15%
2340
December1st to 15thNight
36%5%11%21%20%5%
2340
16th to endNight
44%5%10%20%14%5%
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
12%430%27%20%5%
90
16th to endDay
16%8%32%31%10%1
96
February1st to 15thDay
10%11%24%25%25%3
90
16th to endDay
11%224%43%18%
81
March1st to 15thDay
18%226%40%12%
90
16th to endDay
15%219%29%29%2
278
April1st to 15thDay
13%321%34%23%2
270
16th to endDay
4318%27%37%7%
270
May1st to 15thDay
6%312%31%37%8%
288
16th to endDay
8%5%25%41%17%
331
June1st to 15thDay
12%2214%43%26%
315
16th to endDay
11%1212%34%36%
315
July1st to 15thDay
5%6%33%53%
305
16th to endDay
8%29%32%46%
326
August1st to 15thDay
12%128%33%42%
313
16th to endDay
10%310%32%42%
332
September1st to 15thDay
13%16%18%32%27%
315
16th to endDay
10%424%46%13%
257
October1st to 15thDay
7%12%29%38%11%
255
16th to endDay
9%315%27%30%13%
184
November1st to 15thDay
20%18%32%31%6%
90
16th to endDay
7%124%32%26%7%
90
December1st to 15thDay
11%5%24%40%17%1
90
16th to endDay
27%6%19%20%26%
96
January1st to 15thNight
14%8%29%30%13%2
720
16th to endNight
17%10%29%28%14%
768
February1st to 15thNight
15%7%27%32%16%1
704
16th to endNight
16%5%31%29%16%
631
March1st to 15thNight
13%5%26%33%19%1
720
16th to endNight
11%417%33%28%4
680
April1st to 15thNight
10%319%35%28%2
539
16th to endNight
8%117%30%34%7%
540
May1st to 15thNight
8%211%31%37%7%
540
16th to endNight
7%7%20%46%17%
563
June1st to 15thNight
7%1219%49%19%
540
16th to endNight
7%28%46%35%
540
July1st to 15thNight
427%39%45%
510
16th to endNight
426%43%42%
564
August1st to 15thNight
6%17%40%44%
539
16th to endNight
10%1410%41%31%
573
September1st to 15thNight
10%26%15%39%26%
613
16th to endNight
10%16%24%42%14%
661
October1st to 15thNight
8%19%34%36%9%
660
16th to endNight
10%317%27%32%7%
704
November1st to 15thNight
10%5%19%34%25%6%
700
16th to endNight
11%5%24%33%20%4
720
December1st to 15thNight
13%7%24%29%19%4
720
16th to endNight
19%7%23%29%18%1
768
Page generated at 2017-09-17 12:05:47. Version ac04

Copyright 2017 A. Danko


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