Le Domaine
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Le Domaine clear sky chart from 2005-11-06 to 2024-02-20.

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
24%
22528
12%
80404
7%
22440
31%
22440
12%
59934

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
11%
755
6%
4407
2%
737
17%
737
3%
3515
January11th to 20thNight
16%
755
8%
4403
4%
740
23%
740
4%
3431
January21st to endNight
21%
829
8%
4798
8%
814
29%
814
6%
3907
February1st to 10thNight
17%
760
11%
2470
5%
760
26%
760
10%
1919
February11th to 20thNight
15%
742
12%
2399
4%
739
25%
739
10%
1868
February21st to endNight
18%
592
12%
1828
5%
592
27%
592
11%
1418
March1st to 10thNight
19%
720
13%
2134
7%
720
26%
720
12%
1643
March11th to 20thNight
17%
720
14%
1980
5%
720
26%
720
12%
1530
March21st to endNight
22%
792
19%
2084
7%
792
30%
792
19%
1488
April1st to 10thNight
20%
720
14%
1800
4%
720
25%
720
16%
1380
April11th to 20thNight
27%
711
19%
1775
7%
711
33%
711
22%
1273
April21st to endNight
25%
514
16%
1594
7%
514
34%
514
16%
1136
May1st to 10thNight
32%
360
16%
1440
13%
360
41%
360
16%
958
May11th to 20thNight
29%
354
19%
1416
19%
354
43%
354
15%
954
May21st to endNight
29%
389
12%
1551
11%
388
41%
388
19%
963
June1st to 10thNight
27%
360
9%
1440
9%
360
35%
360
15%
950
June11th to 20thNight
35%
360
10%
1411
10%
360
42%
360
18%
892
June21st to endNight
37%
360
11%
1260
9%
360
44%
360
21%
820
July1st to 10thNight
39%
350
11%
1332
12%
350
45%
350
22%
821
July11th to 20thNight
45%
348
13%
1392
16%
348
51%
348
22%
822
July21st to endNight
46%
394
13%
1486
14%
372
52%
372
23%
895
August1st to 10thNight
45%
372
16%
1436
18%
370
50%
370
23%
868
August11th to 20thNight
49%
534
16%
1598
10%
534
54%
534
28%
1009
August21st to endNight
37%
738
17%
1926
7%
738
42%
738
29%
1308
September1st to 10thNight
39%
720
15%
1800
6%
720
42%
720
29%
1212
September11th to 20thNight
38%
720
18%
1800
9%
720
41%
720
29%
1231
September21st to endNight
35%
720
18%
2052
12%
720
40%
720
23%
1420
October1st to 10thNight
28%
720
16%
2160
10%
720
37%
720
19%
1531
October11th to 20thNight
21%
720
11%
2160
7%
720
28%
720
13%
1697
October21st to endNight
18%
792
11%
2520
6%
792
26%
792
11%
1995
November1st to 10thNight
20%
740
14%
2492
7%
740
30%
740
11%
1870
November11th to 20thNight
15%
760
11%
2660
6%
760
21%
760
8%
2092
November21st to endNight
13%
760
7%
2660
3%
760
17%
760
6%
2248
December1st to 10thNight
13%
760
7%
2660
2%
760
19%
760
5%
2251
December11th to 20thNight
16%
760
9%
3251
5%
758
23%
758
6%
2603
December21st to endNight
12%
827
7%
4829
4%
817
18%
817
3%
4016

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
18%12%5%9%7%45%45%6%26%
78433
Night
17%13%5%9%7%45%445%25%
80734
TransparencyDay
60%29%19%9%1
78138
Night
61%29%18%8%1
80563
SeeingDay
27%14%32%19%7%2
13556
Night
26%12%30%23%8%1
22554

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
15%19%7%14%11%45%445%12%
2517
11th to 20thDay
13%14%7%18%11%44445%17%
2520
21st to endDay
12%18%10%13%9%45%5%45%14%
2846
February1st to 10thDay
8%19%7%13%11%5%6%5%47%16%
1710
11th to 20thDay
11%17%7%13%9%45%45%5%19%
1654
21st to endDay
17%18%6%9%7%45%5%35%22%
1427
March1st to 10thDay
15%16%5%10%8%45%5%45%23%
1820
11th to 20thDay
14%14%5%11%7%46%445%27%
1980
21st to endDay
16%11%47%5%35%45%5%33%
2272
April1st to 10thDay
22%16%48%5%3333428%
2160
11th to 20thDay
21%12%5%7%423347%31%
2134
21st to endDay
20%12%48%5%34445%31%
2379
May1st to 10thDay
20%12%47%435%446%30%
2520
11th to 20thDay
22%9%37%5%35%446%32%
2478
21st to endDay
18%8%36%6%45%46%6%34%
2725
June1st to 10thDay
22%9%37%7%45%5%6%6%25%
2520
11th to 20thDay
14%7%36%5%47%5%7%8%35%
2541
21st to endDay
18%7%48%6%46%5%6%8%27%
2700
July1st to 10thDay
15%7%36%6%45%6%7%8%34%
2580
11th to 20thDay
15%7%36%7%46%6%6%9%30%
2520
21st to endDay
14%8%36%6%46%5%7%8%31%
2744
August1st to 10thDay
16%8%48%7%5%6%6%5%7%28%
2489
11th to 20thDay
17%7%36%7%36%5%6%7%32%
2303
21st to endDay
17%8%27%7%46%5%6%7%32%
2412
September1st to 10thDay
19%7%36%6%24447%38%
2160
11th to 20thDay
18%8%36%5%3445%7%37%
2160
21st to endDay
21%11%36%5%3445%6%33%
1905
October1st to 10thDay
20%13%47%5%2445%7%30%
1800
11th to 20thDay
27%17%5%8%6%3434418%
1800
21st to endDay
28%18%47%5%44335%18%
1836
November1st to 10thDay
17%18%6%10%434435%27%
1583
11th to 20thDay
18%16%8%13%8%3443417%
1520
21st to endDay
23%19%9%13%8%3443410%
1520
December1st to 10thDay
21%21%8%12%8%45%325%11%
1520
11th to 20thDay
20%15%7%12%10%46%5%3413%
1906
21st to endDay
20%19%10%11%9%3333414%
2772
January1st to 10thNight
14%18%8%14%10%45%43415%
4429
11th to 20thNight
12%15%6%14%12%5%5%5%5%5%15%
4440
21st to endNight
10%17%10%15%9%5%7%45%5%13%
4806
February1st to 10thNight
11%13%6%10%11%7%7%45%5%20%
2470
11th to 20thNight
12%16%7%11%10%5%5%5%45%20%
2397
21st to endNight
12%16%6%10%8%5%6%45%5%21%
1828
March1st to 10thNight
15%15%6%10%7%46%5%46%23%
2124
11th to 20thNight
16%14%5%10%7%45%45%426%
1979
21st to endNight
16%12%5%8%5%245%3436%
2084
April1st to 10thNight
20%12%6%9%6%34345%28%
1800
11th to 20thNight
17%10%46%5%4445%5%36%
1775
21st to endNight
22%10%47%6%34445%31%
1594
May1st to 10thNight
18%10%37%5%35%446%34%
1440
11th to 20thNight
20%9%47%5%25%445%35%
1415
21st to endNight
18%7%36%5%3436%7%38%
1550
June1st to 10thNight
18%8%46%6%45%6%6%7%31%
1440
11th to 20thNight
16%7%36%7%36%45%7%37%
1411
21st to endNight
17%7%26%5%446%5%8%36%
1260
July1st to 10thNight
14%6%36%6%35%7%5%9%36%
1372
11th to 20thNight
13%6%345%47%5%8%8%39%
1440
21st to endNight
11%6%35%7%35%6%6%10%38%
1574
August1st to 10thNight
11%8%37%5%35%5%6%8%39%
1446
11th to 20thNight
14%7%35%5%35%6%5%7%41%
1598
21st to endNight
15%7%36%5%345%6%6%39%
1926
September1st to 10thNight
15%8%35%5%3445%7%42%
1800
11th to 20thNight
18%8%25%425%5%5%5%41%
1800
21st to endNight
20%9%46%5%33347%37%
2052
October1st to 10thNight
21%10%36%6%34446%33%
2160
11th to 20thNight
25%16%48%5%33445%24%
2160
21st to endNight
25%17%5%8%6%33445%20%
2520
November1st to 10thNight
19%16%5%8%7%34445%25%
2492
11th to 20thNight
19%15%7%10%8%4444419%
2660
21st to endNight
23%18%7%12%9%3433413%
2660
December1st to 10thNight
19%20%7%12%9%45%43413%
2660
11th to 20thNight
20%18%6%10%7%35%5%45%16%
3288
21st to endNight
19%21%7%13%10%3432314%
4884

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
77%19%9%4
2518
11th to 20thDay
72%2416%6%
2520
21st to endDay
73%25%12%7%1
2846
February1st to 10thDay
69%36%14%8%1
1710
11th to 20thDay
67%18%11%11%1
1663
21st to endDay
66%26%17%10%1
1427
March1st to 10thDay
64%36%17%10%2
1823
11th to 20thDay
61%28%14%11%3
1980
21st to endDay
53%37%19%15%3
2272
April1st to 10thDay
62%18%14%12%3
2160
11th to 20thDay
55%26%23%12%2
2134
21st to endDay
57%27%16%15%3
2379
May1st to 10thDay
55%27%21%12%3
2520
11th to 20thDay
55%26%19%16%1
2482
21st to endDay
51%210%20%15%2
2725
June1st to 10thDay
59%37%20%11%1
2520
11th to 20thDay
47%311%25%13%2
2541
21st to endDay
55%311%21%9%
2700
July1st to 10thDay
46%312%28%10%1
2510
11th to 20thDay
50%312%26%10%
2445
21st to endDay
51%313%26%7%
2591
August1st to 10thDay
55%312%24%6%
2475
11th to 20thDay
51%315%23%8%
2303
21st to endDay
51%311%24%10%
2412
September1st to 10thDay
47%312%25%13%1
2160
11th to 20thDay
48%314%25%9%1
2160
21st to endDay
53%312%24%7%
1905
October1st to 10thDay
56%212%20%10%1
1800
11th to 20thDay
71%210%13%31
1800
21st to endDay
71%28%13%5%1
1836
November1st to 10thDay
62%310%18%7%
1583
11th to 20thDay
72%29%12%6%
1520
21st to endDay
79%37%8%4
1520
December1st to 10thDay
78%26%10%4
1520
11th to 20thDay
75%3312%6%
1906
21st to endDay
76%16%13%3
2772
January1st to 10thNight
75%111%10%3
4429
11th to 20thNight
72%18%14%41
4440
21st to endNight
74%26%11%7%
4806
February1st to 10thNight
66%27%17%8%1
2470
11th to 20thNight
66%27%15%9%1
2399
21st to endNight
65%27%16%10%1
1828
March1st to 10thNight
63%26%16%11%2
2134
11th to 20thNight
62%38%16%10%2
1980
21st to endNight
52%36%20%15%3
2084
April1st to 10thNight
60%16%17%14%2
1800
11th to 20thNight
51%26%25%15%3
1775
21st to endNight
56%26%19%14%2
1594
May1st to 10thNight
52%37%20%15%3
1440
11th to 20thNight
53%35%20%17%2
1416
21st to endNight
47%311%23%14%3
1551
June1st to 10thNight
51%310%25%10%1
1440
11th to 20thNight
47%311%22%14%3
1411
21st to endNight
47%412%26%10%1
1260
July1st to 10thNight
43%415%26%10%1
1332
11th to 20thNight
41%415%30%10%
1392
21st to endNight
43%318%28%8%
1486
August1st to 10thNight
42%418%30%7%
1436
11th to 20thNight
41%419%28%8%
1598
21st to endNight
44%415%28%8%
1926
September1st to 10thNight
43%316%27%11%
1800
11th to 20thNight
44%317%28%8%
1800
21st to endNight
50%312%28%7%
2052
October1st to 10thNight
53%312%21%11%1
2160
11th to 20thNight
65%210%18%41
2160
21st to endNight
67%29%15%5%1
2520
November1st to 10thNight
62%212%18%6%
2492
11th to 20thNight
68%29%14%6%
2660
21st to endNight
76%27%11%3
2660
December1st to 10thNight
76%27%10%4
2660
11th to 20thNight
71%26%14%7%
3288
21st to endNight
77%1412%5%
4884

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
23%21%42%12%21
180
11th to 20thDay
25%16%39%14%42
180
21st to endDay
22%18%35%19%5%
221
February1st to 10thDay
29%24%37%6%4
270
11th to 20thDay
28%26%34%10%1
267
21st to endDay
33%20%34%10%1
293
March1st to 10thDay
28%18%34%17%4
420
11th to 20thDay
30%18%33%15%5%
420
21st to endDay
31%16%34%14%41
462
April1st to 10thDay
35%18%25%15%5%1
420
11th to 20thDay
35%14%25%15%8%2
412
21st to endDay
28%18%33%15%5%1
420
May1st to 10thDay
32%13%31%16%6%1
423
11th to 20thDay
28%15%28%20%8%2
447
21st to endDay
25%17%32%18%7%1
485
June1st to 10thDay
27%10%36%19%6%1
450
11th to 20thDay
22%15%31%19%10%2
471
21st to endDay
21%12%30%26%10%1
630
July1st to 10thDay
16%8%38%28%9%1
505
11th to 20thDay
20%9%35%23%10%3
444
21st to endDay
17%9%29%31%11%2
488
August1st to 10thDay
20%7%32%28%9%4
446
11th to 20thDay
19%5%29%27%14%6%
439
21st to endDay
21%10%31%21%11%6%
495
September1st to 10thDay
23%8%32%21%12%4
450
11th to 20thDay
24%9%29%21%13%4
450
21st to endDay
26%12%26%20%13%3
450
October1st to 10thDay
26%14%28%20%10%2
450
11th to 20thDay
33%17%30%14%41
450
21st to endDay
39%12%27%18%31
423
November1st to 10thDay
33%15%34%13%41
277
11th to 20thDay
28%21%34%13%31
180
21st to endDay
32%23%33%8%31
180
December1st to 10thDay
34%14%33%15%31
180
11th to 20thDay
33%21%34%8%31
180
21st to endDay
32%15%39%10%32
198
January1st to 10thNight
31%14%33%19%3
760
11th to 20thNight
31%14%30%21%5%1
760
21st to endNight
18%12%36%26%7%1
836
February1st to 10thNight
21%16%36%21%6%1
760
11th to 20thNight
24%16%36%20%31
742
21st to endNight
24%18%31%22%41
592
March1st to 10thNight
24%18%32%22%4
720
11th to 20thNight
28%18%30%17%6%1
720
21st to endNight
24%14%33%22%7%1
792
April1st to 10thNight
29%13%29%23%5%
720
11th to 20thNight
27%15%28%21%9%
711
21st to endNight
27%10%31%24%8%1
514
May1st to 10thNight
23%8%30%28%10%1
360
11th to 20thNight
27%9%28%28%8%1
354
21st to endNight
22%10%35%25%8%
389
June1st to 10thNight
24%7%33%27%9%
360
11th to 20thNight
20%8%29%29%13%1
360
21st to endNight
21%5%29%32%12%
360
July1st to 10thNight
15%5%33%39%9%
350
11th to 20thNight
16%6%25%38%14%
348
21st to endNight
14%428%38%15%1
394
August1st to 10thNight
15%5%24%35%20%1
372
11th to 20thNight
17%322%34%21%3
534
21st to endNight
19%5%30%25%17%3
738
September1st to 10thNight
22%5%29%29%14%2
720
11th to 20thNight
25%6%27%25%16%1
720
21st to endNight
26%6%27%27%14%1
720
October1st to 10thNight
27%10%31%23%9%1
720
11th to 20thNight
35%10%28%19%6%2
720
21st to endNight
34%12%29%20%41
792
November1st to 10thNight
30%14%30%19%5%1
740
11th to 20thNight
31%16%31%15%7%1
760
21st to endNight
36%16%24%18%5%1
760
December1st to 10thNight
34%15%29%17%5%1
760
11th to 20thNight
31%14%31%18%5%1
760
21st to endNight
35%15%27%19%41
836
Page generated at 2024-02-17 06:28:42. Version ac07

Copyright 2024 Attilla Danko


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