DMZ Observatories
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the DMZ Observatories clear sky chart from 2005-11-06 to 2024-03-08.

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
74%
24230
35%
79494
31%
24155
80%
24155
50%
36939

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
72%
745
41%
3978
34%
736
77%
736
38%
1434
January11th to 20thNight
73%
747
47%
3881
38%
740
79%
740
48%
1203
January21st to endNight
64%
829
24%
4295
33%
814
74%
814
25%
2225
February1st to 10thNight
72%
760
36%
2380
35%
760
79%
760
51%
1131
February11th to 20thNight
64%
740
34%
2219
29%
740
73%
740
48%
1101
February21st to endNight
60%
628
36%
1799
29%
628
69%
628
49%
916
March1st to 10thNight
61%
750
39%
2062
28%
750
72%
750
53%
1045
March11th to 20thNight
70%
720
38%
1980
29%
720
77%
720
58%
973
March21st to endNight
71%
792
37%
2178
27%
792
78%
792
58%
1061
April1st to 10thNight
71%
720
39%
1980
27%
720
79%
720
67%
895
April11th to 20thNight
65%
599
41%
1843
32%
599
75%
599
64%
777
April21st to endNight
73%
540
46%
1771
41%
540
82%
540
71%
660
May1st to 10thNight
70%
540
43%
1620
32%
540
80%
540
70%
659
May11th to 20thNight
78%
531
43%
1594
37%
531
83%
531
72%
647
May21st to endNight
76%
582
45%
1746
35%
582
83%
582
81%
656
June1st to 10thNight
83%
540
37%
1620
32%
540
84%
540
68%
679
June11th to 20thNight
85%
540
39%
1620
33%
540
87%
540
79%
619
June21st to endNight
85%
540
30%
1620
26%
540
86%
540
60%
736
July1st to 10thNight
82%
525
21%
1575
18%
525
82%
525
42%
838
July11th to 20thNight
78%
522
15%
1566
13%
522
78%
522
29%
999
July21st to endNight
77%
591
13%
1674
11%
558
76%
558
24%
1119
August1st to 10thNight
86%
537
22%
1602
20%
534
85%
534
40%
876
August11th to 20thNight
81%
534
25%
1602
24%
534
81%
534
38%
893
August21st to endNight
81%
682
25%
2058
25%
682
81%
682
38%
1199
September1st to 10thNight
79%
720
27%
1980
25%
720
79%
720
42%
1151
September11th to 20thNight
86%
720
41%
1980
35%
720
86%
720
61%
970
September21st to endNight
82%
720
38%
1980
30%
720
85%
720
61%
961
October1st to 10thNight
79%
720
41%
2034
33%
720
84%
720
68%
911
October11th to 20thNight
83%
720
43%
2160
37%
720
88%
720
69%
902
October21st to endNight
84%
792
45%
2376
40%
792
88%
792
72%
967
November1st to 10thNight
81%
740
45%
2220
39%
740
85%
740
68%
934
November11th to 20thNight
80%
760
42%
2299
39%
760
84%
760
62%
1013
November21st to endNight
67%
760
37%
2470
34%
760
74%
760
46%
1201
December1st to 10thNight
71%
760
38%
2470
38%
760
75%
760
49%
1154
December11th to 20thNight
66%
759
32%
2943
35%
759
72%
759
35%
1552
December21st to endNight
62%
825
24%
4319
34%
817
68%
817
31%
1882

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
331342445%6%64%
79054
Night
331332345%6%66%
80574
TransparencyDay
20%5%6%11%25%33%
78781
Night
18%46%13%27%31%
80369
SeeingDay
5%7%19%31%26%13%
14033
Night
4313%41%33%6%
24283

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
2334424345%66%
2858
11th to 20thDay
33134245%5%467%
2860
21st to endDay
5%425%4245%7%8%55%
3146
February1st to 10thDay
5%323313346%66%
1795
11th to 20thDay
6%414324446%62%
1850
21st to endDay
4314423345%66%
1653
March1st to 10thDay
332443446%6%62%
2058
11th to 20thDay
4413312446%67%
1980
21st to endDay
2212323446%72%
2178
April1st to 10thDay
2112323347%73%
1980
11th to 20thDay
221211222480%
2063
21st to endDay
111121223483%
2184
May1st to 10thDay
1112312235%79%
2340
11th to 20thDay
111211224480%
2301
21st to endDay
1111122387%
2530
June1st to 10thDay
211212246%76%
2340
11th to 20thDay
11111223483%
2340
21st to endDay
3213434446%66%
2340
July1st to 10thDay
4225%6%47%6%7%8%49%
2340
11th to 20thDay
6%5%38%8%5%8%9%8%10%30%
2340
21st to endDay
8%6%37%8%6%7%8%9%10%27%
2545
August1st to 10thDay
5%425%7%5%7%7%7%9%43%
2328
11th to 20thDay
5%425%6%47%7%9%9%42%
2299
21st to endDay
4326%6%46%7%7%8%45%
2289
September1st to 10thDay
6%5%26%6%35%6%48%49%
1980
11th to 20thDay
311333445%6%67%
1980
21st to endDay
3213334346%69%
1980
October1st to 10thDay
2112323446%73%
1925
11th to 20thDay
211231232480%
1800
21st to endDay
2112212347%77%
1980
November1st to 10thDay
1112223437%74%
1859
11th to 20thDay
2212322435%72%
1878
21st to endDay
33243345%5%7%63%
1710
December1st to 10thDay
431443445%7%61%
1710
11th to 20thDay
6%5%245%345%6%7%52%
2169
21st to endDay
432343445%7%61%
3146
January1st to 10thNight
331332345%6%67%
4097
11th to 20thNight
2212212345%76%
4110
21st to endNight
9%5%25%5%3446%7%49%
4521
February1st to 10thNight
331333345%6%66%
2380
11th to 20thNight
332343445%5%64%
2218
21st to endNight
23145%3445%6%64%
1799
March1st to 10thNight
321343445%7%63%
2062
11th to 20thNight
3312323435%70%
1980
21st to endNight
221232345%6%69%
2178
April1st to 10thNight
1221222347%74%
1980
11th to 20thNight
121222322379%
1843
21st to endNight
121111223483%
1771
May1st to 10thNight
211221233480%
1620
11th to 20thNight
112211245%80%
1594
21st to endNight
1111222387%
1746
June1st to 10thNight
2212213245%77%
1620
11th to 20thNight
1111112235%83%
1620
21st to endNight
2212223447%70%
1620
July1st to 10thNight
4214435%5%7%9%54%
1620
11th to 20thNight
2425%6%47%8%11%14%37%
1620
21st to endNight
5%426%6%5%8%8%10%17%29%
1773
August1st to 10thNight
33135%35%5%7%11%54%
1611
11th to 20thNight
2315%426%6%8%13%50%
1602
21st to endNight
4324436%5%8%9%50%
2058
September1st to 10thNight
6%423445%45%8%54%
1980
11th to 20thNight
2313322245%72%
1980
21st to endNight
2313323445%72%
1980
October1st to 10thNight
1112222346%76%
2034
11th to 20thNight
211122232481%
2160
21st to endNight
111222233482%
2376
November1st to 10thNight
1112212345%76%
2220
11th to 20thNight
2213323346%73%
2299
21st to endNight
432343445%6%64%
2470
December1st to 10thNight
422442335%6%65%
2470
11th to 20thNight
45%25%5%35%446%56%
3041
21st to endNight
5%3244245%5%5%61%
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
19%45%10%31%31%
2859
11th to 20thDay
20%35%11%34%26%
2860
21st to endDay
23%6%7%15%32%17%
3146
February1st to 10thDay
20%35%10%24%39%
1795
11th to 20thDay
24%36%12%24%31%
1860
21st to endDay
21%339%28%35%
1653
March1st to 10thDay
21%348%30%34%
2058
11th to 20thDay
19%348%26%39%
1980
21st to endDay
15%2410%35%33%
2178
April1st to 10thDay
12%237%36%39%
1980
11th to 20thDay
11%226%27%52%
2066
21st to endDay
8%236%30%51%
2184
May1st to 10thDay
11%137%21%57%
2340
11th to 20thDay
9%238%24%53%
2304
21st to endDay
6%12426%61%
2530
June1st to 10thDay
10%245%26%54%
2340
11th to 20thDay
6%23320%66%
2340
21st to endDay
18%45%8%19%45%
2340
July1st to 10thDay
29%9%10%14%18%21%
2276
11th to 20thDay
39%14%17%19%7%4
2271
21st to endDay
44%14%18%15%7%2
2404
August1st to 10thDay
33%11%14%15%16%11%
2313
11th to 20thDay
31%12%15%18%15%9%
2299
21st to endDay
31%11%12%19%15%12%
2289
September1st to 10thDay
33%6%10%16%17%18%
1980
11th to 20thDay
17%47%13%26%32%
1980
21st to endDay
16%47%13%31%29%
1980
October1st to 10thDay
11%47%13%29%35%
1925
11th to 20thDay
11%238%31%45%
1800
21st to endDay
10%2410%28%47%
1980
November1st to 10thDay
12%3410%35%36%
1859
11th to 20thDay
15%3411%29%39%
1878
21st to endDay
21%46%12%25%34%
1710
December1st to 10thDay
22%45%15%27%27%
1710
11th to 20thDay
29%47%12%26%21%
2168
21st to endDay
22%46%12%37%19%
3146
January1st to 10thNight
17%5%5%11%37%25%
4097
11th to 20thNight
13%2417%41%23%
4110
21st to endNight
30%7%6%16%27%14%
4521
February1st to 10thNight
19%46%12%21%39%
2380
11th to 20thNight
21%36%13%26%30%
2219
21st to endNight
20%5%410%28%33%
1799
March1st to 10thNight
19%4412%31%31%
2062
11th to 20thNight
17%3410%24%42%
1980
21st to endNight
16%36%12%34%30%
2178
April1st to 10thNight
12%2311%34%38%
1980
11th to 20thNight
12%238%26%49%
1843
21st to endNight
9%139%30%49%
1771
May1st to 10thNight
9%236%27%52%
1620
11th to 20thNight
8%2310%25%52%
1595
21st to endNight
5%125%28%58%
1746
June1st to 10thNight
11%236%24%54%
1620
11th to 20thNight
6%13420%66%
1620
21st to endNight
14%46%8%20%48%
1620
July1st to 10thNight
22%8%15%13%16%26%
1575
11th to 20thNight
28%16%20%21%11%4
1566
21st to endNight
34%16%24%17%7%2
1674
August1st to 10thNight
22%10%15%22%17%13%
1602
11th to 20thNight
23%11%19%19%17%11%
1602
21st to endNight
26%10%15%18%20%11%
2058
September1st to 10thNight
26%7%13%20%17%16%
1980
11th to 20thNight
15%45%14%32%30%
1980
21st to endNight
15%46%15%32%28%
1980
October1st to 10thNight
10%47%17%27%36%
2034
11th to 20thNight
10%3411%28%45%
2160
21st to endNight
9%25%11%28%46%
2376
November1st to 10thNight
11%2413%34%36%
2220
11th to 20thNight
14%2413%29%37%
2299
21st to endNight
22%35%10%29%31%
2470
December1st to 10thNight
21%35%17%26%29%
2470
11th to 20thNight
28%46%14%26%22%
3041
21st to endNight
24%5%5%13%31%22%
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
7%6%22%34%27%4
270
11th to 20thDay
8%5%16%40%23%8%
270
21st to endDay
39%20%38%25%6%
297
February1st to 10thDay
8%10%20%31%24%6%
355
11th to 20thDay
10%16%29%30%14%2
455
21st to endDay
9%17%33%29%9%3
382
March1st to 10thDay
7%16%28%34%11%3
449
11th to 20thDay
7%12%25%28%17%10%
420
21st to endDay
5%17%29%31%13%4
462
April1st to 10thDay
311%32%28%18%9%
420
11th to 20thDay
413%35%27%16%6%
412
21st to endDay
214%30%27%17%10%
420
May1st to 10thDay
314%27%30%16%10%
423
11th to 20thDay
29%27%34%21%7%
448
21st to endDay
28%30%35%19%7%
485
June1st to 10thDay
25%22%43%21%8%
450
11th to 20thDay
2422%39%24%11%
450
21st to endDay
3215%37%31%11%
450
July1st to 10thDay
327%32%35%21%
446
11th to 20thDay
7%16%24%39%24%
444
21st to endDay
8%2420%37%29%
487
August1st to 10thDay
41323%39%30%
447
11th to 20thDay
6%25%21%38%28%
437
21st to endDay
42320%39%32%
495
September1st to 10thDay
8%211%31%34%14%
450
11th to 20thDay
419%35%37%15%
450
21st to endDay
4417%29%30%16%
450
October1st to 10thDay
28%18%29%27%16%
395
11th to 20thDay
4213%28%38%16%
270
21st to endDay
2317%31%30%16%
297
November1st to 10thDay
36%17%37%29%8%
270
11th to 20thDay
3411%35%35%13%
270
21st to endDay
410%22%33%21%10%
270
December1st to 10thDay
6%7%19%32%28%8%
270
11th to 20thDay
6%420%42%23%5%
270
21st to endDay
12%9%21%33%20%6%
297
January1st to 10thNight
5%213%48%27%4
760
11th to 20thNight
6%413%49%25%4
760
21st to endNight
8%317%45%22%3
836
February1st to 10thNight
5%415%47%25%4
760
11th to 20thNight
46%21%49%18%2
744
21st to endNight
5%7%23%49%14%2
628
March1st to 10thNight
35%27%47%15%2
750
11th to 20thNight
45%17%42%28%5%
720
21st to endNight
35%17%46%25%3
792
April1st to 10thNight
2320%49%24%2
720
11th to 20thNight
3425%47%21%1
599
21st to endNight
2419%48%25%2
540
May1st to 10thNight
2322%46%25%2
540
11th to 20thNight
1216%47%31%4
531
21st to endNight
1219%46%30%2
584
June1st to 10thNight
219%50%33%4
540
11th to 20thNight
1110%48%37%2
540
21st to endNight
36%40%45%7%
540
July1st to 10thNight
35%28%55%7%
525
11th to 20thNight
21221%61%12%
522
21st to endNight
5%2218%56%17%
591
August1st to 10thNight
4218%59%18%
537
11th to 20thNight
21418%63%12%
534
21st to endNight
41216%59%18%
682
September1st to 10thNight
6%1425%51%13%
720
11th to 20thNight
3333%52%9%
720
21st to endNight
319%39%39%8%
720
October1st to 10thNight
1214%40%36%7%
720
11th to 20thNight
329%43%37%6%
720
21st to endNight
228%43%35%9%
792
November1st to 10thNight
2111%46%34%6%
740
11th to 20thNight
2111%44%37%5%
760
21st to endNight
6%318%44%23%6%
760
December1st to 10thNight
6%313%47%25%6%
760
11th to 20thNight
7%6%14%49%21%3
760
21st to endNight
7%419%43%22%5%
836
Page generated at 2024-03-05 05:24:03. Version ac07

Copyright © 2024 Attilla Danko.


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