Hahnenberg Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hahnenberg Observatory 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
33%
24579
11%
75056
8%
24525
36%
24525
14%
57829

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
10%
950
2%
2648
1%
946
11%
946
4%
2428
January11th to 20thNight
12%
921
3%
2577
1%
921
14%
921
4%
2385
January21st to endNight
14%
990
2%
2772
1%
990
15%
990
4%
2585
February1st to 10thNight
15%
819
4%
2430
2%
819
17%
819
5%
2172
February11th to 20thNight
17%
700
8%
2099
3%
700
22%
700
8%
1771
February21st to endNight
21%
592
9%
1776
3%
592
26%
592
9%
1458
March1st to 10thNight
33%
720
15%
2160
9%
720
38%
720
18%
1577
March11th to 20thNight
31%
720
17%
2045
10%
720
37%
720
19%
1495
March21st to endNight
35%
715
16%
2101
11%
715
40%
715
19%
1513
April1st to 10thNight
31%
540
11%
1800
8%
540
36%
540
14%
1311
April11th to 20thNight
37%
533
18%
1692
13%
533
42%
533
19%
1179
April21st to endNight
41%
540
16%
1620
10%
540
47%
540
21%
1132
May1st to 10thNight
43%
540
15%
1620
11%
540
46%
540
21%
1120
May11th to 20thNight
45%
531
16%
1490
13%
531
49%
531
21%
1069
May21st to endNight
58%
583
15%
1552
11%
582
61%
582
33%
987
June1st to 10thNight
52%
522
14%
1422
9%
522
56%
522
30%
938
June11th to 20thNight
57%
360
16%
1260
16%
360
60%
360
25%
762
June21st to endNight
58%
534
15%
1434
10%
534
60%
534
33%
918
July1st to 10thNight
68%
525
16%
1400
11%
525
70%
525
41%
817
July11th to 20thNight
63%
522
17%
1392
12%
522
66%
522
37%
848
July21st to endNight
63%
591
17%
1487
14%
558
63%
558
36%
925
August1st to 10thNight
65%
537
18%
1498
15%
534
66%
534
34%
916
August11th to 20thNight
63%
534
19%
1598
14%
534
67%
534
33%
955
August21st to endNight
57%
594
17%
1896
16%
594
60%
594
27%
1169
September1st to 10thNight
56%
540
18%
1800
16%
540
60%
540
27%
1092
September11th to 20thNight
55%
715
20%
1975
16%
715
58%
715
29%
1305
September21st to endNight
46%
720
16%
1980
13%
720
48%
720
23%
1400
October1st to 10thNight
40%
720
17%
1980
12%
720
45%
720
20%
1428
October11th to 20thNight
27%
720
10%
2261
7%
720
32%
720
12%
1769
October21st to endNight
23%
792
9%
2574
8%
792
27%
792
9%
2122
November1st to 10thNight
28%
740
14%
2406
11%
740
34%
740
13%
1837
November11th to 20thNight
17%
760
9%
2470
6%
760
21%
760
7%
2064
November21st to endNight
15%
821
5%
2570
3%
821
18%
821
6%
2241
December1st to 10thNight
10%
950
2%
2850
1%
950
10%
950
3%
2606
December11th to 20thNight
10%
950
2%
3522
1%
949
12%
949
3%
3166
December21st to endNight
9%
1038
2%
4899
0%
1026
11%
1026
2%
4369

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
14%10%5%8%7%3445%6%33%
74516
Night
15%13%5%10%8%45%446%27%
75234
TransparencyDay
52%6%11%20%10%1
74222
Night
60%6%10%16%8%1
75063
SeeingDay
17%9%26%27%16%4
14578
Night
21%9%26%29%13%2
24590

By Month

Percentage Cloud Cover NE (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
13%18%12%19%11%6%43338%
1517
11th to 20thDay
16%17%11%17%14%5%5%3336%
1472
21st to endDay
13%17%13%18%13%5%6%4327%
1584
February1st to 10thDay
9%17%8%14%19%5%6%33411%
1529
11th to 20thDay
13%13%7%15%13%5%6%435%15%
1748
21st to endDay
13%16%8%11%10%46%46%6%17%
1480
March1st to 10thDay
12%11%5%11%10%3445%7%27%
1798
11th to 20thDay
11%9%6%9%8%35%5%45%35%
1914
21st to endDay
16%11%5%7%6%345%6%6%30%
2272
April1st to 10thDay
19%13%48%6%3445%6%29%
2160
11th to 20thDay
19%12%45%43345%6%35%
2216
21st to endDay
16%8%48%5%3446%6%34%
2340
May1st to 10thDay
13%8%36%6%3445%6%41%
2340
11th to 20thDay
14%7%35%5%2445%6%44%
2401
21st to endDay
10%5%345%35%5%6%8%45%
2725
June1st to 10thDay
12%5%25%5%345%6%7%46%
2525
11th to 20thDay
11%425%5%36%5%6%9%45%
2692
21st to endDay
11%6%25%4345%6%8%46%
2520
July1st to 10thDay
8%3233345%6%9%54%
2520
11th to 20thDay
9%4244345%6%8%50%
2520
21st to endDay
7%425%4245%6%10%51%
2743
August1st to 10thDay
8%5%25%4345%6%9%48%
2429
11th to 20thDay
10%425%5%25%46%7%49%
2303
21st to endDay
13%6%26%43336%7%47%
2458
September1st to 10thDay
14%6%245%345%5%7%44%
2147
11th to 20thDay
14%435%435%46%7%45%
1980
21st to endDay
16%6%36%5%35%5%7%7%36%
1980
October1st to 10thDay
18%8%47%6%34447%34%
1980
11th to 20thDay
25%15%48%6%46%45%5%20%
1697
21st to endDay
25%15%5%11%6%45%5%45%17%
1782
November1st to 10thDay
17%18%47%6%3435%6%27%
1672
11th to 20thDay
15%20%7%14%8%35%445%15%
1710
21st to endDay
17%23%9%13%6%3443414%
1601
December1st to 10thDay
16%23%16%18%6%333228%
1330
11th to 20thDay
15%20%10%15%12%5%5%3448%
1671
21st to endDay
20%20%11%12%10%443348%
2760
January1st to 10thNight
14%19%9%17%13%5%432410%
2648
11th to 20thNight
16%19%9%17%12%45%33310%
2577
21st to endNight
13%18%9%15%15%6%6%4338%
2772
February1st to 10thNight
11%17%7%15%17%7%5%42312%
2430
11th to 20thNight
13%13%8%16%12%45%44418%
2098
21st to endNight
17%15%7%13%8%34446%20%
1776
March1st to 10thNight
11%12%5%8%7%45%45%6%33%
2149
11th to 20thNight
10%10%5%10%8%35%5%45%34%
2044
21st to endNight
17%10%48%7%35%45%6%32%
2101
April1st to 10thNight
18%12%47%7%3445%6%30%
1800
11th to 20thNight
20%8%37%5%3445%6%35%
1692
21st to endNight
16%9%46%5%445%5%5%37%
1620
May1st to 10thNight
15%8%37%6%37%45%8%34%
1620
11th to 20thNight
14%9%37%6%35%6%6%5%35%
1490
21st to endNight
10%6%344345%7%9%45%
1551
June1st to 10thNight
13%6%25%5%5%445%7%44%
1422
11th to 20thNight
12%5%35%436%5%6%9%43%
1260
21st to endNight
10%6%25%6%25%35%8%46%
1434
July1st to 10thNight
8%3243345%6%9%52%
1440
11th to 20thNight
8%426%435%5%6%8%50%
1440
21st to endNight
9%425%5%345%6%8%50%
1575
August1st to 10thNight
8%5%25%5%45%5%6%8%48%
1507
11th to 20thNight
10%415%5%445%5%9%49%
1598
21st to endNight
13%6%25%5%3445%6%46%
1896
September1st to 10thNight
11%7%35%5%34447%48%
1800
11th to 20thNight
14%5%25%5%3445%7%46%
1975
21st to endNight
17%6%37%6%345%5%8%36%
1980
October1st to 10thNight
19%8%38%5%34346%36%
1980
11th to 20thNight
24%12%48%5%345%5%6%24%
2261
21st to endNight
25%13%410%7%35%44421%
2574
November1st to 10thNight
16%15%49%6%35%446%27%
2406
11th to 20thNight
17%19%7%12%7%45%34417%
2470
21st to endNight
17%21%8%13%7%44445%14%
2570
December1st to 10thNight
14%22%13%17%10%333239%
2850
11th to 20thNight
14%20%9%18%10%4433410%
3526
21st to endNight
23%21%10%12%6%3433410%
4902

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
85%46%5%1
1518
11th to 20thDay
85%5%5%41
1472
21st to endDay
85%6%441
1584
February1st to 10thDay
80%46%9%1
1529
11th to 20thDay
73%6%8%9%4
1758
21st to endDay
68%6%7%13%41
1480
March1st to 10thDay
57%5%13%17%7%1
1800
11th to 20thDay
52%6%11%22%7%2
1914
21st to endDay
52%7%12%20%7%1
2272
April1st to 10thDay
56%5%10%19%10%
2160
11th to 20thDay
50%5%10%19%14%2
2216
21st to endDay
48%6%12%16%15%3
2340
May1st to 10thDay
44%5%11%25%13%3
2340
11th to 20thDay
41%5%11%24%17%3
2405
21st to endDay
36%7%14%27%14%2
2725
June1st to 10thDay
36%6%12%27%16%2
2525
11th to 20thDay
36%7%13%24%18%2
2692
21st to endDay
36%7%16%25%15%1
2520
July1st to 10thDay
26%7%14%31%19%2
2451
11th to 20thDay
30%7%15%30%17%2
2445
21st to endDay
29%7%15%29%18%2
2591
August1st to 10thDay
32%7%18%31%11%1
2414
11th to 20thDay
34%7%14%30%14%2
2303
21st to endDay
37%5%15%26%15%1
2458
September1st to 10thDay
40%6%13%25%15%1
2147
11th to 20thDay
36%8%16%30%10%1
1980
21st to endDay
45%6%15%25%8%
1980
October1st to 10thDay
52%6%11%22%9%1
1980
11th to 20thDay
68%5%9%14%3
1697
21st to endDay
71%6%11%10%3
1782
November1st to 10thDay
59%6%10%17%7%
1672
11th to 20thDay
72%6%10%9%3
1710
21st to endDay
77%411%7%1
1601
December1st to 10thDay
86%35%5%1
1330
11th to 20thDay
81%7%6%41
1671
21st to endDay
81%6%8%42
2760
January1st to 10thNight
82%5%7%5%1
2648
11th to 20thNight
84%5%6%5%1
2577
21st to endNight
84%5%6%41
2772
February1st to 10thNight
81%46%7%3
2430
11th to 20thNight
71%5%7%12%3
2099
21st to endNight
67%6%9%14%3
1776
March1st to 10thNight
53%6%12%21%8%
2160
11th to 20thNight
52%7%10%19%11%2
2045
21st to endNight
52%5%11%20%10%1
2101
April1st to 10thNight
56%6%9%17%12%1
1800
11th to 20thNight
51%5%8%19%14%3
1692
21st to endNight
49%6%9%20%14%3
1620
May1st to 10thNight
49%5%11%19%12%4
1620
11th to 20thNight
50%6%7%20%15%2
1491
21st to endNight
35%7%15%26%14%3
1552
June1st to 10thNight
40%6%10%28%14%1
1422
11th to 20thNight
37%8%13%24%16%3
1260
21st to endNight
37%6%13%26%16%2
1434
July1st to 10thNight
26%7%16%29%18%4
1400
11th to 20thNight
30%8%14%24%22%2
1392
21st to endNight
33%6%14%29%16%1
1487
August1st to 10thNight
33%7%17%29%12%1
1498
11th to 20thNight
32%8%16%27%16%1
1598
21st to endNight
39%6%13%25%16%1
1896
September1st to 10thNight
37%7%13%22%20%1
1800
11th to 20thNight
39%7%14%28%11%
1975
21st to endNight
46%8%15%24%7%
1980
October1st to 10thNight
51%6%8%21%13%1
1980
11th to 20thNight
62%5%12%16%5%
2261
21st to endNight
68%6%9%13%4
2574
November1st to 10thNight
59%6%10%17%6%1
2406
11th to 20thNight
72%5%10%9%4
2470
21st to endNight
75%6%9%8%1
2570
December1st to 10thNight
84%45%6%1
2850
11th to 20thNight
81%5%8%42
3525
21st to endNight
80%7%9%31
4902

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
18%16%37%21%7%2
270
11th to 20thDay
25%11%38%21%5%1
252
21st to endDay
23%13%32%25%6%1
264
February1st to 10thDay
22%19%39%16%4
240
11th to 20thDay
18%18%41%18%5%
240
21st to endDay
20%24%41%13%2
198
March1st to 10thDay
21%15%39%20%5%
240
11th to 20thDay
19%12%29%27%11%2
354
21st to endDay
24%11%28%24%11%1
462
April1st to 10thDay
24%10%29%27%8%1
420
11th to 20thDay
25%13%27%19%12%3
412
21st to endDay
18%10%29%26%15%3
420
May1st to 10thDay
18%9%30%25%13%4
423
11th to 20thDay
16%428%33%14%4
547
21st to endDay
13%6%23%30%24%5%
679
June1st to 10thDay
13%425%33%21%4
630
11th to 20thDay
13%424%34%20%5%
630
21st to endDay
14%418%36%22%5%
630
July1st to 10thDay
8%217%37%27%9%
621
11th to 20thDay
10%422%33%24%8%
618
21st to endDay
8%321%36%28%5%
684
August1st to 10thDay
10%317%33%28%10%
548
11th to 20thDay
12%318%30%27%11%
439
21st to endDay
16%419%29%25%7%
495
September1st to 10thDay
18%6%22%25%21%8%
450
11th to 20thDay
11%5%24%27%25%8%
450
21st to endDay
19%8%18%28%20%6%
450
October1st to 10thDay
22%11%22%25%16%4
450
11th to 20thDay
29%14%29%21%6%1
324
21st to endDay
32%13%27%22%5%1
297
November1st to 10thDay
27%15%27%18%12%1
270
11th to 20thDay
18%20%41%16%4
270
21st to endDay
26%21%34%16%3
249
December1st to 10thDay
31%16%33%13%7%1
180
11th to 20thDay
27%22%33%16%31
180
21st to endDay
26%20%37%13%21
292
January1st to 10thNight
20%15%37%22%6%1
950
11th to 20thNight
26%14%31%22%7%1
921
21st to endNight
20%11%34%25%8%1
990
February1st to 10thNight
18%15%34%26%7%
819
11th to 20thNight
21%12%34%25%8%
703
21st to endNight
24%15%30%26%5%
592
March1st to 10thNight
17%9%30%31%12%1
720
11th to 20thNight
16%11%34%29%9%1
720
21st to endNight
21%8%26%34%11%1
715
April1st to 10thNight
23%9%29%31%8%1
540
11th to 20thNight
23%8%25%31%12%1
533
21st to endNight
18%6%27%35%12%1
540
May1st to 10thNight
17%426%35%16%1
540
11th to 20thNight
19%322%38%17%2
531
21st to endNight
13%420%35%26%3
584
June1st to 10thNight
16%220%38%21%1
522
11th to 20thNight
11%419%40%24%2
360
21st to endNight
12%218%38%27%2
534
July1st to 10thNight
10%212%42%29%5%
525
11th to 20thNight
10%118%37%29%5%
522
21st to endNight
9%317%38%30%3
591
August1st to 10thNight
10%115%42%28%3
537
11th to 20thNight
11%415%32%32%6%
534
21st to endNight
15%315%38%26%3
594
September1st to 10thNight
15%319%32%27%4
540
11th to 20thNight
17%419%31%23%5%
715
21st to endNight
20%8%19%29%19%5%
720
October1st to 10thNight
23%8%21%28%17%2
720
11th to 20thNight
31%11%24%26%7%1
720
21st to endNight
33%11%26%22%7%1
792
November1st to 10thNight
26%14%24%29%6%1
740
11th to 20thNight
28%17%31%20%4
760
21st to endNight
28%17%30%20%5%
821
December1st to 10thNight
27%20%31%18%4
950
11th to 20thNight
25%15%35%18%5%1
950
21st to endNight
30%13%35%20%2
1045
Page generated at 2024-01-11 22:33:48. Version ac07

Copyright 2024 Attilla Danko


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