Comprix Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Comprix Observatory clear sky chart from 2005-11-06 to 2024-03-18.

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
42%
24096
17%
80234
13%
24002
47%
24002
20%
55221

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
19%
751
11%
4076
7%
737
27%
737
7%
3133
January11th to 20thNight
19%
756
10%
4077
6%
740
25%
740
6%
3207
January21st to endNight
23%
829
7%
4519
9%
814
28%
814
6%
3735
February1st to 10thNight
26%
760
13%
2470
8%
760
31%
760
14%
1836
February11th to 20thNight
23%
740
13%
2238
6%
740
30%
740
15%
1631
February21st to endNight
18%
628
13%
1884
5%
628
27%
628
15%
1421
March1st to 10thNight
30%
760
17%
2192
11%
760
36%
760
21%
1527
March11th to 20thNight
30%
752
20%
2068
10%
752
38%
752
23%
1418
March21st to endNight
29%
792
18%
2178
9%
792
36%
792
21%
1555
April1st to 10thNight
31%
700
16%
1960
8%
700
38%
700
26%
1310
April11th to 20thNight
39%
533
21%
1638
12%
533
46%
533
25%
1068
April21st to endNight
33%
540
19%
1620
8%
540
43%
540
24%
1081
May1st to 10thNight
36%
540
13%
1620
7%
540
41%
540
20%
1147
May11th to 20thNight
48%
531
17%
1593
12%
531
52%
531
23%
1081
May21st to endNight
63%
583
16%
1745
12%
582
66%
582
33%
1067
June1st to 10thNight
61%
540
16%
1620
14%
540
64%
540
32%
977
June11th to 20thNight
63%
540
18%
1620
14%
540
68%
540
34%
974
June21st to endNight
62%
540
19%
1497
15%
540
66%
540
36%
921
July1st to 10thNight
66%
525
16%
1529
16%
525
68%
525
33%
929
July11th to 20thNight
68%
522
19%
1566
16%
522
71%
522
35%
924
July21st to endNight
68%
591
19%
1672
17%
558
70%
558
33%
1020
August1st to 10thNight
70%
537
19%
1600
16%
534
71%
534
35%
933
August11th to 20thNight
68%
534
22%
1598
19%
534
71%
534
32%
988
August21st to endNight
72%
594
26%
1816
24%
594
74%
594
39%
1008
September1st to 10thNight
63%
699
23%
1959
18%
699
65%
699
36%
1181
September11th to 20thNight
69%
720
30%
1980
25%
720
71%
720
41%
1149
September21st to endNight
53%
720
27%
1980
21%
720
58%
720
34%
1227
October1st to 10thNight
56%
720
25%
2033
21%
720
62%
720
34%
1231
October11th to 20thNight
41%
720
22%
2160
16%
720
50%
720
27%
1376
October21st to endNight
36%
792
22%
2420
18%
792
43%
792
22%
1659
November1st to 10thNight
46%
740
24%
2406
20%
740
53%
740
29%
1418
November11th to 20thNight
32%
760
21%
2470
13%
760
43%
760
21%
1646
November21st to endNight
33%
760
17%
2470
13%
760
39%
760
18%
1737
December1st to 10thNight
26%
760
11%
2470
9%
760
30%
760
13%
1904
December11th to 20thNight
27%
759
13%
2981
8%
758
33%
758
11%
2154
December21st to endNight
22%
828
6%
4509
6%
817
27%
817
6%
3648

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
16%10%47%6%45%5%5%7%33%
79146
Night
16%10%47%6%3445%6%35%
80613
TransparencyDay
51%411%21%11%2
78869
Night
50%411%21%12%2
80409
SeeingDay
19%8%24%24%17%8%
14055
Night
19%7%25%32%16%2
24129

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 10thDay
19%18%6%11%6%3445%5%18%
2836
11th to 20thDay
16%19%7%11%8%7%6%34416%
2840
21st to endDay
28%19%9%8%7%4433412%
3124
February1st to 10thDay
22%12%5%9%7%34445%24%
1710
11th to 20thDay
17%11%6%11%8%445%5%5%25%
1825
21st to endDay
20%13%5%7%5%34445%30%
1570
March1st to 10thDay
19%11%5%7%5%3445%7%31%
1987
11th to 20thDay
20%11%48%6%44446%30%
2058
21st to endDay
24%9%48%5%34447%28%
2178
April1st to 10thDay
15%12%46%6%35%446%35%
2016
11th to 20thDay
18%8%36%5%345%5%6%36%
2271
21st to endDay
19%8%46%6%35%5%6%6%32%
2340
May1st to 10thDay
19%8%36%6%45%5%5%7%33%
2340
11th to 20thDay
21%7%36%6%345%6%8%31%
2301
21st to endDay
10%5%26%6%37%6%6%10%38%
2531
June1st to 10thDay
12%5%35%6%45%6%6%10%38%
2340
11th to 20thDay
12%5%26%6%345%7%10%38%
2340
21st to endDay
11%426%6%46%6%7%12%37%
2441
July1st to 10thDay
12%6%36%6%46%6%6%8%39%
2364
11th to 20thDay
10%6%25%5%46%7%6%9%41%
2340
21st to endDay
10%5%35%5%36%6%7%10%39%
2547
August1st to 10thDay
8%436%6%45%7%7%10%41%
2327
11th to 20thDay
11%5%35%6%46%6%8%11%36%
2303
21st to endDay
8%6%245%45%6%6%9%46%
2537
September1st to 10thDay
15%5%2443446%7%48%
1981
11th to 20thDay
10%6%246%35%45%7%47%
1980
21st to endDay
17%6%35%42445%5%44%
1980
October1st to 10thDay
13%6%25%5%4445%8%42%
1926
11th to 20thDay
15%7%25%5%345%5%7%42%
1800
21st to endDay
22%8%37%5%335%5%5%35%
1934
November1st to 10thDay
11%7%35%5%2445%7%48%
1672
11th to 20thDay
16%11%46%6%45%446%35%
1710
21st to endDay
19%10%5%7%5%35%446%32%
1710
December1st to 10thDay
21%15%7%10%6%35%45%5%20%
1710
11th to 20thDay
19%16%6%9%5%2446%5%23%
2153
21st to endDay
24%21%6%9%6%44445%12%
3124
January1st to 10thNight
17%17%7%11%7%44435%20%
4109
11th to 20thNight
16%16%6%14%8%45%445%18%
4120
21st to endNight
27%16%9%8%7%3433317%
4532
February1st to 10thNight
22%12%48%6%34445%29%
2470
11th to 20thNight
19%11%39%7%35%446%28%
2237
21st to endNight
21%12%7%8%5%34345%27%
1884
March1st to 10thNight
18%9%47%6%34446%36%
2192
11th to 20thNight
18%9%446%3445%6%37%
2068
21st to endNight
22%8%46%5%34446%34%
2178
April1st to 10thNight
16%8%45%5%35%5%5%7%39%
1960
11th to 20thNight
15%7%26%5%35%5%5%8%38%
1638
21st to endNight
16%7%36%6%3446%8%36%
1620
May1st to 10thNight
19%6%45%7%35%6%6%6%32%
1620
11th to 20thNight
17%7%36%5%345%5%8%37%
1592
21st to endNight
8%5%25%5%35%6%8%10%43%
1744
June1st to 10thNight
8%5%35%5%45%5%6%8%47%
1620
11th to 20thNight
9%5%24446%5%8%11%44%
1620
21st to endNight
10%424435%5%8%9%45%
1497
July1st to 10thNight
9%5%25%5%35%5%5%8%47%
1574
11th to 20thNight
7%5%25%5%35%6%7%9%47%
1620
21st to endNight
8%5%35%5%35%6%7%7%45%
1771
August1st to 10thNight
6%425%6%346%7%11%44%
1611
11th to 20thNight
8%6%26%6%36%36%9%45%
1598
21st to endNight
8%3145%246%6%9%52%
1816
September1st to 10thNight
15%413434446%52%
1959
11th to 20thNight
10%4144245%46%55%
1980
21st to endNight
14%6%35%43435%6%49%
1980
October1st to 10thNight
11%4245%35%5%5%8%49%
2033
11th to 20thNight
17%7%25%43445%6%43%
2160
21st to endNight
23%7%26%43345%5%37%
2420
November1st to 10thNight
15%6%35%434346%49%
2406
11th to 20thNight
17%10%45%6%35%445%37%
2470
21st to endNight
20%11%46%5%3445%6%31%
2470
December1st to 10thNight
23%13%7%8%5%3435%5%24%
2470
11th to 20thNight
18%14%6%7%6%3445%7%27%
3042
21st to endNight
25%19%6%8%6%34345%16%
4532

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
70%39%13%5%
2837
11th to 20thDay
74%310%10%3
2840
21st to endDay
78%28%8%3
3124
February1st to 10thDay
63%310%15%8%
1710
11th to 20thDay
61%49%18%9%
1835
21st to endDay
59%211%19%8%1
1570
March1st to 10thDay
54%312%24%5%1
1987
11th to 20thDay
56%410%20%9%1
2058
21st to endDay
58%310%21%8%1
2178
April1st to 10thDay
51%411%21%12%2
2016
11th to 20thDay
48%411%20%14%3
2271
21st to endDay
51%5%10%21%10%2
2340
May1st to 10thDay
52%413%22%8%2
2340
11th to 20thDay
51%5%12%18%12%1
2305
21st to endDay
39%7%15%25%12%2
2531
June1st to 10thDay
42%5%11%24%15%2
2340
11th to 20thDay
40%5%16%23%14%1
2340
21st to endDay
40%5%16%21%15%3
2441
July1st to 10thDay
42%5%13%22%16%2
2299
11th to 20thDay
39%6%13%26%16%1
2271
21st to endDay
36%6%14%28%12%3
2405
August1st to 10thDay
37%6%14%29%13%1
2314
11th to 20thDay
40%6%14%28%11%2
2303
21st to endDay
34%6%15%24%16%5%
2537
September1st to 10thDay
36%5%11%24%21%3
1981
11th to 20thDay
36%5%10%27%20%2
1980
21st to endDay
41%48%23%22%1
1980
October1st to 10thDay
41%410%25%19%1
1926
11th to 20thDay
42%411%24%18%2
1800
21st to endDay
52%311%22%10%2
1934
November1st to 10thDay
37%410%28%18%3
1672
11th to 20thDay
52%38%22%12%3
1710
21st to endDay
55%312%20%10%1
1710
December1st to 10thDay
67%310%17%3
1710
11th to 20thDay
63%39%18%6%
2150
21st to endDay
77%39%8%3
3124
January1st to 10thNight
68%210%15%5%
4109
11th to 20thNight
70%210%14%3
4120
21st to endNight
74%28%12%31
4532
February1st to 10thNight
59%49%18%8%1
2470
11th to 20thNight
57%310%19%10%1
2238
21st to endNight
61%210%16%8%2
1884
March1st to 10thNight
51%39%24%12%1
2192
11th to 20thNight
48%311%26%10%3
2068
21st to endNight
52%48%23%13%1
2178
April1st to 10thNight
45%412%23%14%2
1960
11th to 20thNight
45%411%18%19%4
1638
21st to endNight
46%411%23%14%2
1620
May1st to 10thNight
50%6%12%20%10%2
1620
11th to 20thNight
46%6%12%21%13%3
1593
21st to endNight
34%7%17%26%13%3
1745
June1st to 10thNight
34%7%13%24%19%3
1620
11th to 20thNight
33%7%15%25%17%3
1620
21st to endNight
32%7%15%24%19%3
1497
July1st to 10thNight
36%5%12%23%21%3
1529
11th to 20thNight
32%6%12%28%19%2
1566
21st to endNight
35%5%14%28%15%3
1672
August1st to 10thNight
32%6%17%27%17%1
1600
11th to 20thNight
36%5%13%26%18%1
1598
21st to endNight
28%5%14%28%20%5%
1816
September1st to 10thNight
34%412%24%20%6%
1959
11th to 20thNight
29%410%27%26%3
1980
21st to endNight
38%310%22%27%1
1980
October1st to 10thNight
35%5%9%28%21%3
2033
11th to 20thNight
42%49%26%18%2
2160
21st to endNight
48%48%24%13%2
2420
November1st to 10thNight
38%311%26%20%3
2406
11th to 20thNight
49%38%23%15%2
2470
21st to endNight
55%212%21%9%1
2470
December1st to 10thNight
63%39%19%6%
2470
11th to 20thNight
59%311%21%6%
3044
21st to endNight
73%29%13%3
4532

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
26%14%34%18%5%2
270
11th to 20thDay
26%19%36%14%4
270
21st to endDay
32%14%33%15%6%
297
February1st to 10thDay
30%15%32%16%6%
270
11th to 20thDay
27%18%36%14%31
270
21st to endDay
25%17%40%16%2
225
March1st to 10thDay
24%16%32%22%6%
357
11th to 20thDay
26%11%32%23%7%1
449
21st to endDay
29%12%32%20%7%
462
April1st to 10thDay
23%11%31%21%12%3
420
11th to 20thDay
21%14%27%22%10%6%
412
21st to endDay
22%11%32%24%10%2
420
May1st to 10thDay
26%9%27%21%12%4
423
11th to 20thDay
21%5%26%24%18%5%
447
21st to endDay
13%5%20%28%23%11%
485
June1st to 10thDay
14%319%32%22%10%
450
11th to 20thDay
15%418%27%26%10%
450
21st to endDay
12%5%23%28%23%9%
551
July1st to 10thDay
14%49%22%25%26%
469
11th to 20thDay
10%316%24%29%18%
444
21st to endDay
11%210%27%31%18%
488
August1st to 10thDay
11%311%22%34%19%
446
11th to 20thDay
14%315%28%23%16%
439
21st to endDay
9%211%29%31%19%
495
September1st to 10thDay
15%312%24%28%18%
450
11th to 20thDay
11%210%23%36%19%
450
21st to endDay
18%7%15%27%23%10%
450
October1st to 10thDay
13%5%22%29%20%10%
450
11th to 20thDay
15%10%30%28%15%3
450
21st to endDay
24%9%31%25%10%
449
November1st to 10thDay
14%11%29%28%14%4
270
11th to 20thDay
21%19%26%19%13%2
270
21st to endDay
26%10%34%23%5%1
270
December1st to 10thDay
27%12%32%20%7%2
270
11th to 20thDay
23%14%39%18%6%
270
21st to endDay
31%14%29%21%5%
297
January1st to 10thNight
24%13%33%25%5%
760
11th to 20thNight
28%11%32%23%4
760
21st to endNight
26%10%32%28%4
836
February1st to 10thNight
28%9%29%31%3
760
11th to 20thNight
25%10%35%27%3
743
21st to endNight
25%11%37%24%2
628
March1st to 10thNight
22%10%32%30%6%
760
11th to 20thNight
21%11%34%27%7%
752
21st to endNight
26%8%30%27%8%1
792
April1st to 10thNight
19%9%35%28%8%
700
11th to 20thNight
17%7%34%29%13%1
533
21st to endNight
18%6%38%29%8%1
540
May1st to 10thNight
19%7%30%30%13%
540
11th to 20thNight
20%421%37%16%2
531
21st to endNight
9%417%37%31%3
584
June1st to 10thNight
9%318%45%23%1
540
11th to 20thNight
11%217%40%27%2
540
21st to endNight
10%317%43%25%2
540
July1st to 10thNight
11%39%39%30%7%
525
11th to 20thNight
8%210%37%37%6%
522
21st to endNight
10%210%39%37%2
591
August1st to 10thNight
7%19%42%37%4
537
11th to 20thNight
10%29%40%35%4
534
21st to endNight
9%19%38%36%7%
594
September1st to 10thNight
17%212%32%32%5%
699
11th to 20thNight
11%211%35%35%6%
720
21st to endNight
17%318%34%25%2
720
October1st to 10thNight
12%421%38%23%3
720
11th to 20thNight
20%6%28%33%13%1
720
21st to endNight
25%7%27%31%9%
792
November1st to 10thNight
19%5%25%34%17%1
740
11th to 20thNight
21%11%29%29%10%1
760
21st to endNight
25%9%27%31%8%1
760
December1st to 10thNight
29%8%29%29%5%
760
11th to 20thNight
24%8%32%29%5%1
760
21st to endNight
31%10%27%28%3
836
Page generated at 2024-03-15 14:01:45. Version ac07

Copyright © 2024 Attilla Danko.


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