DVHS Espace Academy
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the DVHS Espace Academy clear sky chart from 2005-11-06 to 2024-11-10.

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
62%
24492
29%
96971
24%
24315
70%
24315
38%
45560

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
54%
752
19%
4262
18%
736
58%
736
17%
2225
January11th to 20thNight
56%
750
15%
4095
19%
740
63%
740
14%
2738
January21st to endNight
56%
829
15%
4445
24%
814
61%
814
15%
2958
February1st to 10thNight
55%
760
26%
2470
24%
760
63%
760
29%
1455
February11th to 20thNight
52%
740
27%
2304
22%
740
62%
740
32%
1310
February21st to endNight
52%
628
27%
1884
21%
628
61%
628
36%
1054
March1st to 10thNight
47%
752
19%
3523
14%
744
54%
744
18%
2150
March11th to 20thNight
50%
751
26%
3461
20%
740
57%
740
26%
1548
March21st to endNight
46%
828
14%
3663
12%
814
55%
814
22%
2129
April1st to 10thNight
49%
760
27%
1900
12%
760
57%
760
39%
1161
April11th to 20thNight
45%
751
31%
1879
11%
751
55%
751
45%
1061
April21st to endNight
52%
760
30%
1900
10%
760
61%
760
57%
983
May1st to 10thNight
55%
697
40%
2894
15%
689
64%
689
53%
971
May11th to 20thNight
65%
449
34%
2523
27%
445
75%
445
60%
611
May21st to endNight
57%
404
27%
2709
25%
399
74%
399
55%
591
June1st to 10thNight
58%
380
31%
1520
24%
380
76%
380
51%
586
June11th to 20thNight
65%
380
37%
1520
35%
380
80%
380
69%
472
June21st to endNight
69%
380
38%
1520
37%
380
83%
380
72%
471
July1st to 10thNight
75%
360
47%
2064
40%
360
90%
360
82%
413
July11th to 20thNight
79%
465
36%
2038
33%
462
87%
462
68%
626
July21st to endNight
77%
614
37%
2286
27%
580
86%
580
76%
691
August1st to 10thNight
73%
561
45%
2289
26%
555
82%
555
63%
785
August11th to 20thNight
75%
686
39%
2385
22%
677
82%
677
84%
748
August21st to endNight
80%
823
40%
2881
27%
814
84%
814
76%
993
September1st to 10thNight
79%
760
48%
1900
28%
760
86%
760
86%
824
September11th to 20thNight
72%
760
45%
1900
29%
760
80%
760
71%
904
September21st to endNight
77%
760
44%
2148
38%
760
84%
760
74%
892
October1st to 10thNight
72%
742
48%
3332
31%
740
83%
740
55%
1082
October11th to 20thNight
72%
745
30%
3238
38%
740
80%
740
53%
1094
October21st to endNight
71%
820
41%
3830
39%
813
79%
813
44%
1439
November1st to 10thNight
69%
778
34%
2411
30%
778
77%
778
46%
1198
November11th to 20thNight
67%
760
28%
2470
28%
760
72%
760
39%
1299
November21st to endNight
65%
760
29%
2607
29%
760
70%
760
38%
1334
December1st to 10thNight
57%
760
22%
2660
20%
760
63%
760
27%
1547
December11th to 20thNight
53%
760
17%
3237
20%
759
58%
759
17%
2215
December21st to endNight
45%
827
13%
4823
17%
817
54%
817
13%
3002

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
5%313222246%67%
105108
Night
7%313333346%64%
102760
TransparencyDay
20%47%19%25%25%
104863
Night
23%49%18%22%24%
102594
SeeingDay
7%10%25%32%21%6%
15357
Night
7%5%20%39%24%4
24673

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
15%9%49%44436%6%36%
2617
11th to 20thDay
16%12%410%444346%34%
2860
21st to endDay
19%10%38%5%4445%7%31%
3146
February1st to 10thDay
12%6%38%444446%45%
1710
11th to 20thDay
12%5%26%44436%7%47%
1763
21st to endDay
12%4244445%47%51%
1570
March1st to 10thDay
9%7%39%7%7%6%5%7%7%33%
3340
11th to 20thDay
8%425%33335%6%59%
3490
21st to endDay
9%6%26%5%5%6%47%8%42%
3912
April1st to 10thDay
10%6%2443346%8%49%
2280
11th to 20thDay
7%41433335%6%61%
2249
21st to endDay
431323335%9%66%
2280
May1st to 10thDay
5%212112235%77%
3893
11th to 20thDay
21211113483%
4243
21st to endDay
211112135%82%
4813
June1st to 10thDay
2313222248%70%
2660
11th to 20thDay
11112245%83%
2660
21st to endDay
111111122386%
2660
July1st to 10thDay
111393%
4420
11th to 20thDay
11111112387%
4238
21st to endDay
111112490%
4455
August1st to 10thDay
111112246%80%
4091
11th to 20thDay
11112490%
3811
21st to endDay
11111112389%
4180
September1st to 10thDay
1111112488%
2280
11th to 20thDay
1112112346%77%
2280
21st to endDay
2212122225%81%
2028
October1st to 10thDay
1113222236%77%
3180
11th to 20thDay
3212122235%77%
3161
21st to endDay
321323335%8%68%
3448
November1st to 10thDay
6%41433335%8%59%
1870
11th to 20thDay
8%6%35%5%4445%7%50%
1710
21st to endDay
10%6%25%33336%7%55%
1568
December1st to 10thDay
11%8%36%44436%7%44%
1520
11th to 20thDay
22%12%48%5%43345%30%
1928
21st to endDay
14%9%49%44446%8%33%
2794
January1st to 10thNight
13%6%36%44435%7%46%
4313
11th to 20thNight
17%10%37%5%4436%6%34%
4110
21st to endNight
17%8%37%5%45%46%7%35%
4521
February1st to 10thNight
14%5%25%444345%51%
2470
11th to 20thNight
11%42444345%8%51%
2302
21st to endNight
11%424333346%57%
1884
March1st to 10thNight
11%6%27%5%5%5%5%6%7%42%
3530
11th to 20thNight
10%5%13333335%62%
3490
21st to endNight
8%5%26%5%5%5%46%8%47%
3741
April1st to 10thNight
7%42444435%8%55%
1900
11th to 20thNight
6%314334346%63%
1879
21st to endNight
42222336%8%69%
1900
May1st to 10thNight
212212235%80%
3067
11th to 20thNight
11111125%84%
2649
21st to endNight
11111112485%
2762
June1st to 10thNight
222222247%72%
1520
11th to 20thNight
1111122486%
1520
21st to endNight
11111122486%
1520
July1st to 10thNight
11294%
2540
11th to 20thNight
11111112387%
2722
21st to endNight
11112236%84%
3109
August1st to 10thNight
211112138%79%
2848
11th to 20thNight
11112489%
3033
21st to endNight
11111111488%
3498
September1st to 10thNight
11112135%86%
1900
11th to 20thNight
1211122148%77%
1900
21st to endNight
11122223483%
2148
October1st to 10thNight
2112122245%79%
3800
11th to 20thNight
112222247%77%
3777
21st to endNight
411323345%7%68%
4121
November1st to 10thNight
6%41323335%8%63%
2411
11th to 20thNight
8%41433335%8%57%
2470
21st to endNight
8%41433435%7%59%
2607
December1st to 10thNight
11%6%35%34345%6%49%
2660
11th to 20thNight
19%8%37%45%447%8%32%
3276
21st to endNight
15%7%38%6%5%5%45%6%36%
4862

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
47%6%13%25%8%2
2617
11th to 20thDay
53%5%11%14%12%4
2860
21st to endDay
52%6%10%17%12%3
3146
February1st to 10thDay
39%5%9%22%18%7%
1710
11th to 20thDay
36%6%10%20%22%6%
1772
21st to endDay
33%6%10%24%21%6%
1570
March1st to 10thDay
47%8%12%16%15%2
3340
11th to 20thDay
26%5%11%29%17%12%
3490
21st to endDay
37%8%15%25%12%3
3912
April1st to 10thDay
34%7%12%21%21%6%
2280
11th to 20thDay
24%5%14%26%24%7%
2252
21st to endDay
17%413%30%30%6%
2280
May1st to 10thDay
12%37%32%27%19%
3893
11th to 20thDay
8%2424%42%20%
4246
21st to endDay
9%38%36%36%8%
4814
June1st to 10thDay
15%410%25%31%14%
2660
11th to 20thDay
5%37%21%37%27%
2660
21st to endDay
7%1311%32%46%
2660
July1st to 10thDay
2125%14%77%
4351
11th to 20thDay
6%127%14%69%
4164
21st to endDay
2115%26%64%
4315
August1st to 10thDay
7%227%26%56%
4076
11th to 20thDay
2117%37%51%
3849
21st to endDay
5%139%36%46%
4179
September1st to 10thDay
5%228%31%52%
2280
11th to 20thDay
9%45%22%38%22%
2280
21st to endDay
9%2419%37%29%
2028
October1st to 10thDay
11%2312%27%45%
3180
11th to 20thDay
11%36%27%32%21%
3161
21st to endDay
16%27%24%36%15%
3448
November1st to 10thDay
25%6%9%28%23%11%
1870
11th to 20thDay
33%412%25%21%5%
1710
21st to endDay
30%411%21%26%7%
1568
December1st to 10thDay
37%7%12%21%16%7%
1520
11th to 20thDay
57%5%8%14%13%3
1928
21st to endDay
47%5%16%18%11%2
2794
January1st to 10thNight
37%5%21%24%10%3
4313
11th to 20thNight
50%7%14%13%10%7%
4110
21st to endNight
49%6%13%16%12%5%
4521
February1st to 10thNight
35%5%8%21%22%9%
2470
11th to 20thNight
31%5%11%22%23%9%
2304
21st to endNight
29%5%11%29%21%6%
1884
March1st to 10thNight
42%7%16%16%15%4
3530
11th to 20thNight
27%5%8%27%20%12%
3490
21st to endNight
35%8%14%26%12%4
3741
April1st to 10thNight
29%6%13%22%22%8%
1900
11th to 20thNight
23%5%12%29%20%11%
1879
21st to endNight
15%5%12%31%29%8%
1900
May1st to 10thNight
10%411%28%31%17%
3067
11th to 20thNight
6%35%17%42%27%
2649
21st to endNight
6%38%34%38%11%
2762
June1st to 10thNight
14%411%24%31%16%
1520
11th to 20thNight
6%27%17%34%33%
1520
21st to endNight
6%3212%29%49%
1520
July1st to 10thNight
211413%79%
2500
11th to 20thNight
5%225%12%73%
2673
21st to endNight
412420%69%
3011
August1st to 10thNight
8%217%20%62%
2839
11th to 20thNight
2116%26%63%
3061
21st to endNight
6%128%30%53%
3498
September1st to 10thNight
4237%26%58%
1900
11th to 20thNight
8%5%420%34%29%
1900
21st to endNight
7%35%19%33%34%
2148
October1st to 10thNight
10%25%11%18%54%
3800
11th to 20thNight
10%36%27%27%27%
3777
21st to endNight
16%36%22%30%23%
4121
November1st to 10thNight
21%5%10%27%22%16%
2411
11th to 20thNight
26%5%11%26%24%8%
2470
21st to endNight
26%5%9%22%27%11%
2607
December1st to 10thNight
34%7%10%20%17%11%
2660
11th to 20thNight
50%5%11%14%16%3
3276
21st to endNight
46%6%15%17%12%3
4862

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
25%10%24%22%16%3
232
11th to 20thDay
16%9%21%28%21%6%
370
21st to endDay
14%8%20%27%23%8%
407
February1st to 10thDay
16%14%20%21%21%7%
370
11th to 20thDay
15%16%25%20%19%5%
412
21st to endDay
12%17%23%27%18%3
382
March1st to 10thDay
15%15%28%26%12%3
460
11th to 20thDay
17%14%25%23%16%6%
460
21st to endDay
12%17%31%26%12%2
506
April1st to 10thDay
12%18%29%22%14%6%
460
11th to 20thDay
10%17%32%22%13%5%
452
21st to endDay
220%28%29%15%5%
460
May1st to 10thDay
5%14%35%30%14%2
463
11th to 20thDay
5%12%33%29%19%2
488
21st to endDay
311%28%36%18%4
529
June1st to 10thDay
313%30%33%18%3
490
11th to 20thDay
111%31%38%16%2
490
21st to endDay
15%28%41%21%4
490
July1st to 10thDay
225%49%20%4
486
11th to 20thDay
220%47%27%4
484
21st to endDay
1222%45%25%6%
531
August1st to 10thDay
1425%46%20%5%
487
11th to 20thDay
425%41%22%7%
477
21st to endDay
1218%45%27%7%
539
September1st to 10thDay
419%41%28%8%
490
11th to 20thDay
28%23%38%21%7%
490
21st to endDay
16%21%36%26%11%
490
October1st to 10thDay
28%22%29%27%13%
490
11th to 20thDay
5%8%18%26%29%14%
490
21st to endDay
6%8%20%28%25%13%
539
November1st to 10thDay
7%9%23%21%28%12%
412
11th to 20thDay
7%7%15%33%25%13%
270
21st to endDay
10%5%22%31%28%4
203
December1st to 10thDay
17%11%19%24%21%8%
180
11th to 20thDay
19%12%17%20%25%7%
180
21st to endDay
18%12%23%25%18%4
198
January1st to 10thNight
16%5%16%33%23%6%
760
11th to 20thNight
13%6%16%35%25%6%
760
21st to endNight
15%5%16%34%25%5%
836
February1st to 10thNight
15%7%16%35%23%4
760
11th to 20thNight
10%9%20%32%24%4
744
21st to endNight
11%10%22%36%18%2
628
March1st to 10thNight
14%11%20%33%20%3
760
11th to 20thNight
13%10%21%33%19%3
760
21st to endNight
11%9%28%34%16%1
836
April1st to 10thNight
9%8%26%37%17%2
760
11th to 20thNight
7%12%32%29%17%3
751
21st to endNight
5%9%32%34%18%2
760
May1st to 10thNight
46%33%39%16%3
699
11th to 20thNight
2425%48%20%1
455
21st to endNight
26%32%44%15%
411
June1st to 10thNight
2432%49%12%
380
11th to 20thNight
15%27%53%13%1
380
21st to endNight
1227%52%19%
380
July1st to 10thNight
122%57%20%
370
11th to 20thNight
1117%55%25%2
471
21st to endNight
2117%47%32%1
624
August1st to 10thNight
2121%44%28%3
567
11th to 20thNight
121%49%27%1
695
21st to endNight
1116%50%30%3
836
September1st to 10thNight
1218%45%31%4
760
11th to 20thNight
2322%45%26%3
760
21st to endNight
1415%42%32%6%
760
October1st to 10thNight
3418%39%30%6%
760
11th to 20thNight
3416%38%33%5%
760
21st to endNight
5%415%37%30%9%
836
November1st to 10thNight
6%416%36%31%7%
778
11th to 20thNight
8%314%40%30%5%
760
21st to endNight
8%416%35%30%6%
760
December1st to 10thNight
13%6%16%36%23%6%
760
11th to 20thNight
19%6%13%34%23%4
760
21st to endNight
17%8%20%34%20%2
836
Page generated at 2024-11-07 03:55:43. Version ac07

Copyright © 2024 Attilla Danko.


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