Cielos Oscuros
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cielos Oscuros clear sky chart from 2005-11-06 to 2024-01-15.

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
71%
24259
38%
74125
31%
24215
78%
24215
55%
33934

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 10thNight
63%
756
33%
2457
29%
756
72%
756
42%
1226
January11th to 20thNight
69%
740
38%
2405
35%
740
78%
740
48%
1134
January21st to endNight
62%
792
40%
2458
33%
792
73%
792
46%
1217
February1st to 10thNight
65%
720
36%
2160
32%
720
73%
720
48%
1081
February11th to 20thNight
60%
700
40%
2099
32%
700
73%
700
48%
1014
February21st to endNight
57%
592
35%
1776
31%
592
68%
592
47%
875
March1st to 10thNight
59%
720
32%
2160
27%
720
70%
720
46%
1073
March11th to 20thNight
61%
720
34%
2030
27%
720
71%
720
49%
1035
March21st to endNight
59%
792
37%
2134
22%
792
70%
792
54%
1052
April1st to 10thNight
59%
720
37%
1800
19%
720
68%
720
54%
948
April11th to 20thNight
57%
711
38%
1779
18%
711
67%
711
56%
901
April21st to endNight
66%
644
43%
1724
23%
644
74%
644
67%
769
May1st to 10thNight
60%
540
38%
1620
23%
540
69%
540
57%
715
May11th to 20thNight
68%
531
41%
1595
28%
531
75%
531
64%
670
May21st to endNight
68%
582
37%
1746
27%
582
74%
582
63%
723
June1st to 10thNight
70%
540
36%
1620
27%
540
76%
540
71%
639
June11th to 20thNight
70%
522
38%
1602
31%
522
75%
522
70%
632
June21st to endNight
86%
360
41%
1440
49%
360
91%
360
75%
448
July1st to 10thNight
89%
375
40%
1425
44%
375
92%
375
70%
480
July11th to 20thNight
86%
522
34%
1566
29%
522
87%
522
60%
699
July21st to endNight
82%
591
36%
1674
31%
558
84%
558
53%
816
August1st to 10thNight
83%
590
40%
1655
29%
587
85%
587
68%
733
August11th to 20thNight
88%
712
40%
1780
25%
712
89%
712
73%
844
August21st to endNight
89%
792
45%
1980
31%
792
91%
792
75%
918
September1st to 10thNight
83%
720
41%
1844
30%
720
86%
720
69%
879
September11th to 20thNight
86%
720
46%
1980
38%
720
91%
720
77%
837
September21st to endNight
82%
720
47%
1980
39%
720
90%
720
76%
839
October1st to 10thNight
75%
720
43%
1980
34%
720
84%
720
68%
892
October11th to 20thNight
80%
720
49%
1985
41%
720
86%
720
71%
866
October21st to endNight
74%
792
43%
2546
40%
792
84%
792
65%
1000
November1st to 10thNight
75%
740
40%
2405
40%
740
82%
740
62%
986
November11th to 20thNight
78%
760
41%
2470
40%
760
86%
760
59%
1037
November21st to endNight
69%
760
40%
2470
38%
760
78%
760
56%
1064
December1st to 10thNight
66%
760
34%
2470
32%
760
73%
760
45%
1220
December11th to 20thNight
62%
758
34%
2898
31%
758
70%
758
35%
1456
December21st to endNight
57%
825
21%
4412
29%
817
67%
817
23%
2216

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
2212223346%73%
75231
Night
2213323346%71%
74578
TransparencyDay
15%2314%27%38%
74955
Night
16%3314%27%36%
74377
SeeingDay
5%9%25%36%20%5%
14284
Night
45%16%38%31%6%
24282

By Month

Percentage Cloud Cover SW (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 10thDay
4313313447%64%
1708
11th to 20thDay
5%413223238%66%
1660
21st to endDay
5%32432235%6%65%
1894
February1st to 10thDay
4413323446%67%
1800
11th to 20thDay
3213323447%67%
1750
21st to endDay
5%423323345%65%
1480
March1st to 10thDay
341332346%6%65%
1800
11th to 20thDay
331332335%8%65%
1930
21st to endDay
221232446%7%68%
2218
April1st to 10thDay
2323323347%68%
2160
11th to 20thDay
1212312235%77%
2129
21st to endDay
1211213345%77%
2236
May1st to 10thDay
1112212246%77%
2340
11th to 20thDay
1112212236%79%
2301
21st to endDay
1113222346%76%
2530
June1st to 10thDay
1212212235%80%
2340
11th to 20thDay
11111122487%
2346
21st to endDay
11121222384%
2520
July1st to 10thDay
1112213235%77%
2484
11th to 20thDay
3212323345%72%
2340
21st to endDay
231343446%7%61%
2545
August1st to 10thDay
221221225%5%77%
2271
11th to 20thDay
211212246%79%
2122
21st to endDay
2111212335%79%
2376
September1st to 10thDay
2212312235%78%
2114
11th to 20thDay
11111123386%
1980
21st to endDay
111111223485%
1980
October1st to 10thDay
3212212335%76%
1980
11th to 20thDay
212112225%81%
1973
21st to endDay
112111236%82%
1805
November1st to 10thDay
1111222345%77%
1674
11th to 20thDay
2313212246%75%
1710
21st to endDay
4212223348%69%
1710
December1st to 10thDay
3325%32445%6%64%
1710
11th to 20thDay
6%425%5%2447%8%53%
2169
21st to endDay
5%5%245%45%6%7%7%52%
3146
January1st to 10thNight
442442345%6%62%
2457
11th to 20thNight
322342345%6%66%
2405
21st to endNight
5%42432345%5%65%
2458
February1st to 10thNight
4424333336%67%
2160
11th to 20thNight
3323323446%67%
2098
21st to endNight
4313323346%66%
1776
March1st to 10thNight
23243235%5%8%63%
2160
11th to 20thNight
332232345%9%63%
2030
21st to endNight
3312223446%70%
2134
April1st to 10thNight
2322223447%69%
1800
11th to 20thNight
2213323446%72%
1779
21st to endNight
1112212337%78%
1724
May1st to 10thNight
1212212346%75%
1620
11th to 20thNight
1112212336%78%
1594
21st to endNight
1211212335%79%
1746
June1st to 10thNight
11211235%83%
1620
11th to 20thNight
111111222384%
1602
21st to endNight
111111122386%
1440
July1st to 10thNight
1111211235%82%
1466
11th to 20thNight
2112324347%72%
1620
21st to endNight
32133335%6%8%63%
1773
August1st to 10thNight
211222225%5%76%
1664
11th to 20thNight
1111212246%79%
1780
21st to endNight
111122223481%
1980
September1st to 10thNight
1213212245%77%
1844
11th to 20thNight
11111122386%
1980
21st to endNight
11211222386%
1980
October1st to 10thNight
2211213335%78%
1980
11th to 20thNight
111121133481%
1985
21st to endNight
121111224481%
2546
November1st to 10thNight
1212222236%77%
2405
11th to 20thNight
1212213446%74%
2470
21st to endNight
3312222245%73%
2470
December1st to 10thNight
3424424446%63%
2470
11th to 20thNight
5%42442445%9%56%
3041
21st to endNight
45%36%6%35%5%5%8%50%
4521

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 10thDay
21%45%26%33%11%
1709
11th to 20thDay
20%3426%34%13%
1660
21st to endDay
21%35%23%35%12%
1894
February1st to 10thDay
21%35%17%31%24%
1800
11th to 20thDay
18%3416%34%24%
1760
21st to endDay
24%25%18%30%22%
1480
March1st to 10thDay
20%45%18%32%21%
1800
11th to 20thDay
20%3418%33%22%
1930
21st to endDay
17%36%22%33%19%
2218
April1st to 10thDay
19%3418%29%27%
2160
11th to 20thDay
13%2316%31%35%
2132
21st to endDay
12%2315%34%34%
2236
May1st to 10thDay
11%3316%31%36%
2340
11th to 20thDay
10%2113%33%41%
2304
21st to endDay
12%2312%35%36%
2530
June1st to 10thDay
11%139%22%54%
2340
11th to 20thDay
6%116%20%66%
2346
21st to endDay
9%21313%72%
2520
July1st to 10thDay
11%225%13%66%
2417
11th to 20thDay
16%329%20%50%
2271
21st to endDay
22%3314%22%37%
2404
August1st to 10thDay
12%227%18%59%
2256
11th to 20thDay
10%217%25%56%
2122
21st to endDay
11%217%22%57%
2376
September1st to 10thDay
13%227%19%58%
2114
11th to 20thDay
6%116%26%59%
1980
21st to endDay
8%117%27%56%
1980
October1st to 10thDay
15%2210%28%44%
1980
11th to 20thDay
9%2211%29%48%
1973
21st to endDay
8%1210%33%45%
1805
November1st to 10thDay
11%3313%41%30%
1674
11th to 20thDay
14%25%15%33%31%
1710
21st to endDay
16%35%17%33%26%
1710
December1st to 10thDay
22%47%19%28%20%
1710
11th to 20thDay
30%310%22%26%10%
2168
21st to endDay
32%37%26%23%10%
3146
January1st to 10thNight
24%45%20%33%14%
2457
11th to 20thNight
20%4323%33%18%
2405
21st to endNight
22%35%23%29%18%
2458
February1st to 10thNight
22%35%15%29%26%
2160
11th to 20thNight
20%3317%28%29%
2099
21st to endNight
20%35%17%32%23%
1776
March1st to 10thNight
20%5%5%19%30%22%
2160
11th to 20thNight
20%4417%29%26%
2030
21st to endNight
18%2424%32%20%
2134
April1st to 10thNight
18%3419%29%28%
1800
11th to 20thNight
15%3316%29%34%
1779
21st to endNight
9%3216%35%35%
1724
May1st to 10thNight
13%3314%29%38%
1620
11th to 20thNight
10%2213%31%41%
1595
21st to endNight
10%2312%34%38%
1746
June1st to 10thNight
8%2210%23%56%
1620
11th to 20thNight
9%16%19%64%
1602
21st to endNight
7%11412%76%
1440
July1st to 10thNight
8%216%16%67%
1425
11th to 20thNight
14%4210%20%50%
1566
21st to endNight
20%3316%19%38%
1674
August1st to 10thNight
12%228%17%59%
1655
11th to 20thNight
10%328%22%56%
1780
21st to endNight
9%225%23%58%
1980
September1st to 10thNight
12%227%19%57%
1844
11th to 20thNight
8%117%21%61%
1980
21st to endNight
8%16%24%60%
1980
October1st to 10thNight
12%2210%26%48%
1980
11th to 20thNight
9%229%27%51%
1985
21st to endNight
9%3310%24%50%
2546
November1st to 10thNight
13%2213%37%33%
2405
11th to 20thNight
13%3314%31%36%
2470
21st to endNight
16%2315%31%33%
2470
December1st to 10thNight
23%35%16%28%23%
2470
11th to 20thNight
26%5%7%19%30%14%
3041
21st to endNight
34%29%22%24%10%
4521

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 10thDay
11%9%29%35%14%2
270
11th to 20thDay
15%7%24%33%18%3
254
21st to endDay
8%11%23%32%22%4
376
February1st to 10thDay
10%10%25%34%16%5%
420
11th to 20thDay
10%16%30%28%14%2
415
21st to endDay
10%18%30%31%10%1
346
March1st to 10thDay
10%20%29%28%12%1
420
11th to 20thDay
10%15%31%30%12%3
420
21st to endDay
9%18%32%31%9%1
462
April1st to 10thDay
8%16%30%29%15%3
420
11th to 20thDay
6%22%37%23%10%2
412
21st to endDay
5%21%29%29%11%5%
420
May1st to 10thDay
6%15%33%31%12%3
423
11th to 20thDay
313%29%35%16%4
448
21st to endDay
411%30%35%16%4
485
June1st to 10thDay
5%8%29%34%19%5%
450
11th to 20thDay
29%26%35%22%7%
450
21st to endDay
26%27%40%20%6%
450
July1st to 10thDay
2322%45%22%7%
446
11th to 20thDay
3117%43%26%10%
444
21st to endDay
2212%46%29%9%
487
August1st to 10thDay
2421%42%23%8%
447
11th to 20thDay
2214%44%27%11%
437
21st to endDay
1220%41%28%7%
495
September1st to 10thDay
2417%42%26%8%
450
11th to 20thDay
16%24%42%24%3
450
21st to endDay
37%21%36%28%5%
450
October1st to 10thDay
39%24%37%24%4
450
11th to 20thDay
35%23%38%27%4
443
21st to endDay
5%6%20%36%26%8%
297
November1st to 10thDay
47%26%32%25%6%
270
11th to 20thDay
6%5%19%39%24%8%
270
21st to endDay
46%26%32%26%7%
270
December1st to 10thDay
4327%44%19%3
270
11th to 20thDay
5%7%24%36%23%5%
270
21st to endDay
12%11%30%27%17%2
297
January1st to 10thNight
9%6%17%37%24%8%
760
11th to 20thNight
5%416%39%29%7%
740
21st to endNight
7%419%41%23%6%
792
February1st to 10thNight
5%6%17%41%25%6%
720
11th to 20thNight
6%9%20%38%22%5%
704
21st to endNight
8%9%21%41%16%5%
592
March1st to 10thNight
49%22%44%17%4
720
11th to 20thNight
6%8%21%33%26%7%
720
21st to endNight
410%23%39%21%2
792
April1st to 10thNight
411%22%37%23%3
720
11th to 20thNight
312%24%37%21%4
711
21st to endNight
29%20%40%23%6%
644
May1st to 10thNight
47%25%40%21%2
540
11th to 20thNight
110%19%34%33%3
531
21st to endNight
19%19%39%28%3
584
June1st to 10thNight
2421%39%32%2
540
11th to 20thNight
15%21%36%33%4
522
21st to endNight
129%44%41%3
360
July1st to 10thNight
116%41%47%5%
375
11th to 20thNight
217%40%46%3
522
21st to endNight
316%34%53%3
591
August1st to 10thNight
2110%40%44%3
590
11th to 20thNight
117%28%55%8%
712
21st to endNight
216%32%49%11%
792
September1st to 10thNight
218%29%49%10%
720
11th to 20thNight
119%40%42%7%
720
21st to endNight
2311%36%37%11%
720
October1st to 10thNight
3316%41%33%4
720
11th to 20thNight
2213%40%34%10%
720
21st to endNight
35%15%33%33%11%
792
November1st to 10thNight
2415%36%34%9%
740
11th to 20thNight
2312%42%34%6%
760
21st to endNight
45%16%38%32%5%
760
December1st to 10thNight
5%417%42%26%6%
760
11th to 20thNight
8%6%17%41%23%6%
760
21st to endNight
7%9%19%38%22%4
836
Page generated at 2024-01-12 13:17:49. Version ac07

Copyright 2024 Attilla Danko


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