Halbmond Observatorium
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Halbmond Observatorium clear sky chart from 2005-11-05 to 2018-02-13.

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
47%
16301
26%
48985
18%
16256
55%
16256
32%
28766

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
30%
974
26%
2522
9%
970
41%
970
28%
1624
January16th to endNight
28%
1040
28%
2704
10%
1040
40%
1040
31%
1700
February1st to 15thNight
24%
919
21%
2424
7%
916
33%
916
27%
1576
February16th to endNight
26%
604
29%
1866
11%
604
41%
604
27%
1100
March1st to 15thNight
29%
540
23%
1980
15%
540
40%
540
21%
1208
March16th to endNight
34%
576
21%
2112
15%
576
44%
576
23%
1274
April1st to 15thNight
33%
539
26%
1800
14%
539
50%
539
30%
988
April16th to endNight
37%
540
25%
1800
18%
540
51%
540
30%
1020
May1st to 15thNight
50%
540
20%
1758
17%
540
58%
540
28%
1057
May16th to endNight
50%
563
23%
1685
17%
561
58%
561
33%
1013
June1st to 15thNight
74%
540
24%
1509
21%
540
78%
540
48%
821
June16th to endNight
74%
540
26%
1589
25%
540
77%
540
45%
844
July1st to 15thNight
72%
510
18%
1530
18%
510
75%
510
36%
881
July16th to endNight
84%
564
26%
1594
29%
531
84%
531
44%
847
August1st to 15thNight
79%
539
25%
1661
28%
536
81%
536
43%
869
August16th to endNight
74%
573
25%
1910
31%
573
75%
573
32%
1100
September1st to 15thNight
70%
540
26%
1800
29%
540
72%
540
34%
1007
September16th to endNight
68%
594
34%
1973
32%
594
72%
594
38%
1053
October1st to 15thNight
57%
720
31%
2160
23%
720
62%
720
39%
1195
October16th to endNight
50%
768
38%
2304
23%
768
62%
768
41%
1224
November1st to 15thNight
48%
760
30%
2280
21%
760
56%
760
34%
1305
November16th to endNight
41%
803
31%
2519
20%
803
53%
803
31%
1452
December1st to 15thNight
35%
975
22%
2730
11%
975
44%
975
28%
1749
December16th to endNight
31%
1040
23%
2775
11%
1040
40%
1040
25%
1859

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
13%5%2443445%6%44%
49013
Night
12%424423346%50%
49181
TransparencyDay
39%410%22%18%4
48714
Night
34%39%23%22%6%
48985
SeeingDay
13%6%21%27%22%7%
6144
Night
14%8%24%30%19%2
16302

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
19%42432334447%
1746
16th to endDay
16%5%2432323449%
1872
February1st to 15thDay
18%6%24314345%45%
1700
16th to endDay
18%6%35%5%2424441%
1616
March1st to 15thDay
20%6%345%24335%41%
1980
16th to endDay
16%7%36%5%34346%39%
2110
April1st to 15thDay
13%5%35%323347%47%
2147
16th to endDay
16%5%25%43435%5%42%
2160
May1st to 15thDay
17%6%25%5%34446%38%
2190
16th to endDay
10%5%26%6%47%6%6%7%35%
2430
June1st to 15thDay
7%3245%46%6%6%7%44%
2438
16th to endDay
5%3146%47%6%7%10%41%
2358
July1st to 15thDay
7%5%35%6%47%6%8%10%35%
2340
16th to endDay
5%3246%47%6%8%9%42%
2466
August1st to 15thDay
7%415%6%38%7%7%9%38%
2288
16th to endDay
9%435%6%36%6%6%8%39%
2292
September1st to 15thDay
13%5%145%3346%6%44%
2160
16th to endDay
11%313424446%51%
1970
October1st to 15thDay
12%5%24323345%51%
1800
16th to endDay
14%212212236%59%
1920
November1st to 15thDay
13%423312346%55%
1908
16th to endDay
14%7%25%423225%49%
1765
December1st to 15thDay
18%6%24313335%44%
1560
16th to endDay
19%7%34423435%41%
1797
January1st to 15thNight
18%6%2331223350%
2522
16th to endNight
16%5%2432323451%
2704
February1st to 15thNight
19%7%24312336%45%
2415
16th to endNight
15%5%23313335%51%
1866
March1st to 15thNight
19%5%24424335%44%
1980
16th to endNight
13%6%346%24345%45%
2112
April1st to 15thNight
10%3145%2346%8%51%
1800
16th to endNight
10%425%323446%50%
1800
May1st to 15thNight
13%5%13434446%47%
1757
16th to endNight
9%426%5%2435%9%45%
1683
June1st to 15thNight
321342446%9%57%
1509
16th to endNight
431232445%9%56%
1589
July1st to 15thNight
32146%35%6%7%11%44%
1620
16th to endNight
3113425%5%6%13%52%
1702
August1st to 15thNight
42133345%6%12%51%
1671
16th to endNight
6%3244446%7%9%45%
1910
September1st to 15thNight
9%414323447%53%
1800
16th to endNight
7%3144235%46%56%
1973
October1st to 15thNight
9%314423345%56%
2160
16th to endNight
11%31332222363%
2304
November1st to 15thNight
11%414323346%54%
2280
16th to endNight
15%5%23313335%53%
2519
December1st to 15thNight
17%6%25%422345%46%
2730
16th to endNight
19%7%24423335%43%
2775

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%25%24%19%5%
1747
16th to endDay
40%2423%22%5%
1872
February1st to 15thDay
41%39%24%17%4
1702
16th to endDay
47%26%20%18%4
1616
March1st to 15thDay
46%38%17%17%6%
1980
16th to endDay
45%310%23%14%1
2112
April1st to 15thDay
36%410%23%19%5%
2147
16th to endDay
42%48%21%19%3
2160
May1st to 15thDay
46%5%9%16%19%3
2190
16th to endDay
42%6%14%22%12%1
2434
June1st to 15thDay
35%6%11%26%19%1
2438
16th to endDay
34%6%12%24%18%2
2358
July1st to 15thDay
38%7%14%24%13%1
2201
16th to endDay
33%7%15%26%14%1
2311
August1st to 15thDay
36%7%14%24%14%2
2274
16th to endDay
39%7%14%21%14%3
2292
September1st to 15thDay
38%5%10%19%18%7%
2160
16th to endDay
32%39%23%24%7%
1970
October1st to 15thDay
34%39%21%22%8%
1800
16th to endDay
28%3324%29%11%
1920
November1st to 15thDay
31%28%24%24%7%
1908
16th to endDay
40%26%19%24%6%
1765
December1st to 15thDay
42%38%22%15%6%
1560
16th to endDay
46%29%20%16%4
1797
January1st to 15thNight
39%26%21%25%4
2522
16th to endNight
37%15%22%24%7%
2704
February1st to 15thNight
41%28%23%19%5%
2424
16th to endNight
36%26%25%19%8%
1866
March1st to 15thNight
43%28%16%19%8%
1980
16th to endNight
41%28%23%20%2
2112
April1st to 15thNight
31%310%23%21%9%
1800
16th to endNight
33%49%23%24%4
1800
May1st to 15thNight
37%410%21%18%6%
1758
16th to endNight
34%416%26%16%1
1685
June1st to 15thNight
22%5%13%32%24%2
1509
16th to endNight
23%5%12%28%24%5%
1589
July1st to 15thNight
27%9%17%27%15%2
1530
16th to endNight
22%7%16%32%18%2
1594
August1st to 15thNight
23%5%17%31%18%2
1661
16th to endNight
32%6%13%26%17%3
1910
September1st to 15thNight
30%6%10%24%21%7%
1800
16th to endNight
27%48%23%26%9%
1973
October1st to 15thNight
29%38%22%23%12%
2160
16th to endNight
27%1418%33%13%
2304
November1st to 15thNight
31%36%22%24%10%
2280
16th to endNight
35%26%18%30%7%
2519
December1st to 15thNight
41%28%20%19%6%
2730
16th to endNight
44%37%21%18%4
2775

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
24%14%38%17%5%
135
16th to endDay
19%23%36%14%4
144
February1st to 15thDay
23%15%42%14%21
126
16th to endDay
22%20%34%18%21
81
March1st to 15thDay
33%15%41%5%4
90
16th to endDay
12%29%19%33%5%
96
April1st to 15thDay
18%13%34%21%10%1
266
16th to endDay
23%8%28%23%14%2
270
May1st to 15thDay
17%10%32%24%12%3
327
16th to endDay
12%6%26%30%17%5%
517
June1st to 15thDay
7%116%35%30%9%
495
16th to endDay
5%319%32%28%9%
495
July1st to 15thDay
6%216%35%30%8%
475
16th to endDay
5%5%30%38%19%
515
August1st to 15thDay
8%19%31%34%15%
441
16th to endDay
15%9%23%36%15%
332
September1st to 15thDay
12%19%22%41%12%
315
16th to endDay
10%116%33%28%9%
196
October1st to 15thDay
10%5%28%34%17%4
135
16th to endDay
17%6%31%29%9%4
144
November1st to 15thDay
22%10%26%22%16%2
135
16th to endDay
20%13%29%25%9%1
135
December1st to 15thDay
17%18%31%19%11%2
135
16th to endDay
27%19%40%9%4
144
January1st to 15thNight
22%15%28%27%5%
975
16th to endNight
18%14%35%27%4
1040
February1st to 15thNight
23%13%35%24%3
919
16th to endNight
20%15%35%25%3
604
March1st to 15thNight
20%11%35%27%4
540
16th to endNight
17%10%32%29%9%
576
April1st to 15thNight
13%12%37%25%9%
539
16th to endNight
11%10%36%28%11%
540
May1st to 15thNight
16%6%23%39%12%1
540
16th to endNight
12%326%31%23%2
563
June1st to 15thNight
3112%41%37%3
540
16th to endNight
5%210%42%34%5%
540
July1st to 15thNight
2112%33%45%5%
510
16th to endNight
3430%50%10%
564
August1st to 15thNight
417%31%44%11%
539
16th to endNight
8%16%32%44%6%
573
September1st to 15thNight
10%110%28%43%5%
540
16th to endNight
9%114%31%37%4
594
October1st to 15thNight
11%321%30%29%3
720
16th to endNight
12%6%26%32%20%1
768
November1st to 15thNight
11%9%25%34%17%1
760
16th to endNight
18%11%26%28%15%
803
December1st to 15thNight
20%8%30%30%8%
975
16th to endNight
23%12%28%28%5%
1040
Page generated at 2018-02-13 19:46:10. Version ac04

Copyright 2018 A. Danko


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