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 2018-04-23.

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%
16053
23%
49556
19%
16009
65%
16009
31%
29641

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
40%
780
22%
2389
12%
776
51%
776
26%
1494
January16th to endNight
37%
832
25%
2496
14%
832
47%
832
25%
1613
February1st to 15thNight
43%
763
26%
2287
15%
759
53%
759
30%
1409
February16th to endNight
44%
683
24%
2049
14%
683
52%
683
28%
1293
March1st to 15thNight
48%
780
23%
2340
13%
780
56%
780
32%
1400
March16th to endNight
59%
737
26%
2203
19%
737
64%
737
35%
1273
April1st to 15thNight
58%
584
25%
1947
22%
584
64%
584
33%
1090
April16th to endNight
67%
558
30%
1858
28%
558
73%
558
41%
940
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
70%
717
26%
1980
22%
717
72%
717
34%
1224
October1st to 15thNight
71%
720
31%
1980
26%
720
74%
720
42%
1135
October16th to endNight
63%
768
34%
2217
30%
768
67%
768
38%
1262
November1st to 15thNight
59%
760
29%
2471
27%
760
66%
760
37%
1325
November16th to endNight
54%
780
29%
2535
25%
780
63%
780
34%
1406
December1st to 15thNight
47%
780
24%
2535
19%
780
55%
780
27%
1530
December16th to endNight
42%
832
19%
2704
15%
832
48%
832
21%
1770

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%
49928
Night
9%42442445%8%47%
49775
TransparencyDay
34%8%15%20%15%5%
49643
Night
33%7%14%19%17%7%
49564
SeeingDay
11%212%23%31%19%
5887
Night
11%316%25%29%12%
16057

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
11%425%5%2435%8%44%
1876
16th to endDay
16%6%25%423445%44%
2080
February1st to 15thDay
13%6%24424447%45%
1900
16th to endDay
13%424324348%47%
1710
March1st to 15thDay
10%6%245%23437%50%
1950
16th to endDay
10%5%25%434447%48%
2380
April1st to 15thDay
10%5%2442345%7%48%
2331
16th to endDay
6%31432436%8%55%
2216
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%45%
1980
October1st to 15thDay
6%41331346%9%55%
1980
16th to endDay
8%414422345%59%
2002
November1st to 15thDay
8%413324447%56%
1717
16th to endDay
7%31443445%7%54%
1755
December1st to 15thDay
11%5%345%34447%46%
1755
16th to endDay
19%8%35%5%34346%35%
1872
January1st to 15thNight
12%6%24424446%45%
2389
16th to endNight
15%7%35%424346%43%
2496
February1st to 15thNight
14%5%23323346%49%
2283
16th to endNight
13%6%24424346%47%
2049
March1st to 15thNight
10%5%25%42445%8%47%
2340
16th to endNight
10%314423448%51%
2203
April1st to 15thNight
9%423425%447%50%
1947
16th to endNight
6%312324347%59%
1858
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
8%424435%46%9%47%
1980
October1st to 15thNight
5%31342346%9%55%
1980
16th to endNight
8%323423336%57%
2217
November1st to 15thNight
7%5%14422347%55%
2471
16th to endNight
9%423323446%55%
2535
December1st to 15thNight
11%6%25%424446%46%
2535
16th to endNight
15%7%35%43445%5%38%
2704

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
37%5%10%18%21%6%
1877
16th to endDay
41%5%7%15%21%8%
2080
February1st to 15thDay
38%49%17%21%7%
1902
16th to endDay
35%6%10%19%19%7%
1710
March1st to 15thDay
33%5%10%22%21%6%
1950
16th to endDay
34%5%15%20%17%7%
2381
April1st to 15thDay
34%5%10%23%19%6%
2331
16th to endDay
25%6%14%25%20%6%
2216
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
32%10%15%18%17%5%
1980
October1st to 15thDay
25%6%13%21%20%12%
1980
16th to endDay
28%46%15%27%18%
2002
November1st to 15thDay
28%410%21%25%9%
1717
16th to endDay
28%6%10%21%21%12%
1755
December1st to 15thDay
36%6%12%20%19%5%
1755
16th to endDay
49%5%9%19%12%4
1872
January1st to 15thNight
38%5%10%13%24%7%
2389
16th to endNight
42%37%14%21%9%
2496
February1st to 15thNight
36%46%18%22%10%
2292
16th to endNight
38%5%8%15%20%10%
2049
March1st to 15thNight
34%5%12%18%21%7%
2340
16th to endNight
30%5%11%23%19%9%
2203
April1st to 15thNight
31%5%13%17%23%8%
1947
16th to endNight
24%411%30%21%7%
1858
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
32%7%17%19%17%5%
1980
October1st to 15thNight
26%6%10%23%19%14%
1980
16th to endNight
30%36%14%26%18%
2217
November1st to 15thNight
29%38%21%27%10%
2471
16th to endNight
30%48%19%21%15%
2535
December1st to 15thNight
37%5%11%20%19%6%
2535
16th to endNight
45%5%10%20%14%5%
2704

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
13%5%34%27%16%3
135
16th to endDay
17%7%31%33%9%
144
February1st to 15thDay
17%8%26%26%19%2
135
16th to endDay
10%218%50%17%
120
March1st to 15thDay
15%231%37%13%
135
16th to endDay
15%222%32%25%2
341
April1st to 15thDay
13%321%33%25%2
330
16th to endDay
5%320%27%36%7%
289
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
9%321%48%16%
314
October1st to 15thDay
8%12%28%35%13%
315
16th to endDay
10%217%27%29%12%
240
November1st to 15thDay
14%18%32%35%7%
135
16th to endDay
6%120%29%35%6%
135
December1st to 15thDay
17%424%34%19%
135
16th to endDay
25%421%25%22%
144
January1st to 15thNight
15%8%29%30%13%2
780
16th to endNight
17%9%29%28%14%
832
February1st to 15thNight
17%7%26%31%15%1
764
16th to endNight
15%430%31%17%
683
March1st to 15thNight
12%427%34%18%1
780
16th to endNight
11%418%34%26%3
737
April1st to 15thNight
11%319%34%29%2
584
16th to endNight
8%118%30%33%6%
558
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%23%43%14%
717
October1st to 15thNight
9%110%33%36%9%
720
16th to endNight
10%417%28%31%7%
768
November1st to 15thNight
9%5%18%34%25%6%
760
16th to endNight
11%5%23%32%23%4
780
December1st to 15thNight
14%7%24%28%20%4
780
16th to endNight
19%7%23%29%18%1
832
Page generated at 2018-04-24 10:02:59. Version ac04

Copyright 2018 A. Danko


Fort Pickens Clear Sky Chart |Charts Home