Observatoire de Saint-Camille
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoire de Saint-Camille clear sky chart from 2005-11-06 to 2024-01-27.

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
27%
22726
11%
75212
7%
22687
32%
22687
13%
56667

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
12%
760
6%
2649
2%
757
16%
757
5%
2279
January11th to 20thNight
14%
760
6%
2660
3%
760
17%
760
5%
2255
January21st to endNight
20%
820
8%
2868
5%
820
25%
820
8%
2294
February1st to 10thNight
13%
720
9%
2471
4%
720
20%
720
7%
2026
February11th to 20thNight
14%
703
9%
2100
2%
700
21%
700
8%
1735
February21st to endNight
19%
592
12%
1776
6%
592
27%
592
11%
1403
March1st to 10thNight
18%
720
13%
2160
7%
720
26%
720
12%
1675
March11th to 20thNight
21%
720
13%
2086
5%
720
29%
720
13%
1620
March21st to endNight
26%
792
18%
2025
7%
792
32%
792
17%
1543
April1st to 10thNight
24%
720
12%
1800
4%
720
29%
720
16%
1412
April11th to 20thNight
26%
659
16%
1723
6%
659
32%
659
20%
1249
April21st to endNight
23%
540
15%
1620
7%
540
30%
540
14%
1205
May1st to 10thNight
24%
523
14%
1603
8%
523
33%
523
16%
1162
May11th to 20thNight
32%
354
17%
1416
16%
354
43%
354
15%
933
May21st to endNight
35%
389
12%
1551
11%
388
45%
388
15%
1026
June1st to 10thNight
32%
360
9%
1440
9%
360
40%
360
14%
997
June11th to 20thNight
40%
360
11%
1440
15%
360
46%
360
18%
908
June21st to endNight
39%
360
8%
1440
10%
360
44%
360
15%
984
July1st to 10thNight
44%
350
11%
1400
14%
350
50%
350
18%
882
July11th to 20thNight
50%
348
12%
1392
18%
348
53%
348
19%
879
July21st to endNight
50%
394
12%
1486
16%
372
51%
372
17%
968
August1st to 10thNight
52%
362
14%
1426
15%
360
55%
360
19%
892
August11th to 20thNight
48%
532
15%
1596
11%
532
51%
532
23%
1091
August21st to endNight
45%
750
17%
1938
9%
750
48%
750
28%
1338
September1st to 10thNight
43%
720
12%
1800
5%
720
45%
720
25%
1287
September11th to 20thNight
47%
720
18%
1949
12%
720
49%
720
30%
1269
September21st to endNight
41%
720
19%
1980
14%
720
45%
720
26%
1333
October1st to 10thNight
36%
720
19%
1988
12%
720
42%
720
21%
1404
October11th to 20thNight
30%
720
12%
2283
8%
720
35%
720
13%
1713
October21st to endNight
23%
792
10%
2574
6%
792
29%
792
11%
1990
November1st to 10thNight
21%
740
12%
2407
8%
740
28%
740
12%
1799
November11th to 20thNight
22%
760
15%
2470
11%
760
28%
760
11%
1891
November21st to endNight
20%
760
10%
2626
7%
760
26%
760
9%
2082
December1st to 10thNight
14%
836
5%
2818
1%
836
17%
836
5%
2429
December11th to 20thNight
14%
826
7%
3416
4%
825
18%
825
4%
2921
December21st to endNight
12%
824
5%
4835
2%
817
18%
817
3%
3793

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
21%12%5%8%6%3445%6%27%
74562
Night
20%13%5%8%6%34445%27%
75469
TransparencyDay
59%410%18%8%1
74267
Night
61%410%18%8%1
75299
SeeingDay
29%16%27%18%8%2
13597
Night
27%13%25%25%9%1
22738

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
19%20%10%13%9%45%43310%
1517
11th to 20thDay
19%17%6%15%9%35%43417%
1520
21st to endDay
11%17%8%11%9%47%44419%
1632
February1st to 10thDay
15%19%7%14%9%5%5%44315%
1483
11th to 20thDay
15%21%9%13%7%4443416%
1748
21st to endDay
15%17%8%11%8%45%44420%
1480
March1st to 10thDay
16%15%7%11%7%44445%24%
1797
11th to 20thDay
18%15%6%8%7%445%35%26%
1873
21st to endDay
17%16%5%10%5%35%33428%
2330
April1st to 10thDay
23%15%5%10%6%3344424%
2160
11th to 20thDay
21%12%46%5%34335%34%
2186
21st to endDay
25%13%47%5%33445%27%
2340
May1st to 10thDay
24%9%47%5%34345%31%
2371
11th to 20thDay
21%8%35%6%35%5%47%33%
2478
21st to endDay
21%8%36%6%45%6%6%7%29%
2725
June1st to 10thDay
28%7%36%5%35%46%8%26%
2520
11th to 20thDay
20%6%36%5%45%5%5%9%33%
2520
21st to endDay
24%7%48%6%45%5%5%7%26%
2520
July1st to 10thDay
18%7%36%5%45%5%6%8%33%
2520
11th to 20thDay
18%6%37%6%45%6%6%9%30%
2520
21st to endDay
20%7%35%5%35%6%7%9%30%
2744
August1st to 10thDay
21%5%27%6%36%6%6%8%30%
2485
11th to 20thDay
17%6%46%5%35%6%7%8%32%
2304
21st to endDay
20%6%25%6%446%6%7%35%
2415
September1st to 10thDay
18%7%25%6%3445%7%37%
2160
11th to 20thDay
22%6%2432445%6%41%
2010
21st to endDay
21%7%35%43447%9%34%
1980
October1st to 10thDay
26%9%35%5%345%5%6%29%
1970
11th to 20thDay
22%14%46%6%45%5%5%5%24%
1676
21st to endDay
28%17%47%5%3433420%
1782
November1st to 10thDay
21%17%46%5%34445%28%
1671
11th to 20thDay
19%17%8%8%6%34445%22%
1710
21st to endDay
20%20%8%8%6%3444418%
1552
December1st to 10thDay
23%22%8%11%8%2343313%
1354
11th to 20thDay
21%16%8%11%7%3434322%
1737
21st to endDay
24%19%7%13%6%2332317%
2772
January1st to 10thNight
18%20%9%13%9%4443413%
2649
11th to 20thNight
16%18%8%15%9%45%43316%
2660
21st to endNight
12%16%7%12%9%5%7%5%45%19%
2868
February1st to 10thNight
14%17%7%13%10%46%44419%
2471
11th to 20thNight
14%17%7%13%8%5%5%43420%
2098
21st to endNight
16%14%7%10%7%5%5%43424%
1776
March1st to 10thNight
16%16%8%9%7%3434426%
2150
11th to 20thNight
19%14%5%8%6%45%34427%
2085
21st to endNight
19%12%5%8%6%35%44431%
2025
April1st to 10thNight
24%13%5%7%5%3345%427%
1800
11th to 20thNight
21%10%46%5%35%445%34%
1723
21st to endNight
23%13%37%5%34446%29%
1620
May1st to 10thNight
25%10%46%42445%6%30%
1603
11th to 20thNight
19%10%46%5%25%447%34%
1415
21st to endNight
20%7%35%5%35%5%5%7%34%
1550
June1st to 10thNight
26%8%36%4235%7%8%27%
1440
11th to 20thNight
22%6%35%4245%6%9%35%
1440
21st to endNight
20%7%37%6%36%45%7%30%
1440
July1st to 10thNight
16%5%36%6%35%46%9%35%
1440
11th to 20thNight
15%5%36%7%45%7%6%9%35%
1440
21st to endNight
17%6%35%5%45%6%6%8%36%
1574
August1st to 10thNight
17%5%245%45%6%8%9%36%
1436
11th to 20thNight
17%7%37%5%3445%8%36%
1596
21st to endNight
17%7%36%5%345%5%8%39%
1938
September1st to 10thNight
19%8%35%6%3445%5%38%
1800
11th to 20thNight
19%5%25%42345%7%45%
1949
21st to endNight
21%6%25%424446%42%
1980
October1st to 10thNight
21%8%36%5%44446%35%
1988
11th to 20thNight
23%12%46%6%345%45%27%
2283
21st to endNight
28%13%36%5%345%4425%
2574
November1st to 10thNight
22%14%48%6%2445%5%27%
2407
11th to 20thNight
19%14%7%9%6%34445%26%
2470
21st to endNight
20%17%7%11%6%3434422%
2626
December1st to 10thNight
23%21%8%11%7%3433413%
2818
11th to 20thNight
21%19%7%13%7%3433315%
3453
21st to endNight
24%20%6%10%6%2333319%
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
80%46%8%2
1518
11th to 20thDay
74%36%11%5%1
1520
21st to endDay
69%37%13%6%1
1632
February1st to 10thDay
75%35%10%5%1
1483
11th to 20thDay
74%27%10%5%1
1757
21st to endDay
68%46%14%6%1
1480
March1st to 10thDay
65%37%15%7%3
1800
11th to 20thDay
62%39%13%11%2
1873
21st to endDay
63%37%16%10%2
2330
April1st to 10thDay
65%38%14%8%2
2160
11th to 20thDay
55%28%21%13%1
2186
21st to endDay
60%28%16%10%3
2340
May1st to 10thDay
55%37%20%13%2
2371
11th to 20thDay
52%411%21%11%1
2482
21st to endDay
53%5%11%18%12%1
2725
June1st to 10thDay
57%5%10%20%7%1
2520
11th to 20thDay
49%6%12%23%10%1
2520
21st to endDay
58%5%11%19%8%
2520
July1st to 10thDay
47%6%14%24%8%
2450
11th to 20thDay
49%5%15%24%6%
2445
21st to endDay
51%5%15%22%6%
2591
August1st to 10thDay
51%6%17%23%3
2471
11th to 20thDay
48%6%18%20%8%
2304
21st to endDay
47%5%14%23%11%
2415
September1st to 10thDay
47%5%14%24%9%1
2160
11th to 20thDay
43%5%11%28%12%
2010
21st to endDay
47%5%12%25%9%1
1980
October1st to 10thDay
55%5%12%20%8%
1970
11th to 20thDay
61%314%18%4
1676
21st to endDay
68%48%14%5%1
1782
November1st to 10thDay
61%311%18%7%
1671
11th to 20thDay
66%39%13%7%1
1710
21st to endDay
69%412%12%3
1552
December1st to 10thDay
78%37%9%3
1354
11th to 20thDay
70%45%15%6%
1737
21st to endDay
76%25%10%6%
2772
January1st to 10thNight
77%46%10%3
2649
11th to 20thNight
75%37%10%41
2660
21st to endNight
68%48%13%6%1
2868
February1st to 10thNight
71%46%13%6%1
2471
11th to 20thNight
71%37%12%7%
2100
21st to endNight
65%47%14%10%1
1776
March1st to 10thNight
64%37%16%8%2
2160
11th to 20thNight
62%48%13%11%2
2086
21st to endNight
58%36%20%10%3
2025
April1st to 10thNight
61%38%16%11%1
1800
11th to 20thNight
53%37%23%12%2
1723
21st to endNight
58%48%19%10%2
1620
May1st to 10thNight
56%36%20%14%2
1603
11th to 20thNight
50%49%20%13%2
1416
21st to endNight
49%6%11%20%13%1
1551
June1st to 10thNight
54%412%20%8%
1440
11th to 20thNight
46%5%11%25%12%2
1440
21st to endNight
53%5%12%20%9%
1440
July1st to 10thNight
45%5%16%21%11%
1400
11th to 20thNight
44%7%16%24%9%
1392
21st to endNight
48%6%15%23%8%
1486
August1st to 10thNight
43%7%19%26%6%
1426
11th to 20thNight
47%5%16%22%9%
1596
21st to endNight
44%5%15%26%9%
1938
September1st to 10thNight
48%5%12%24%11%1
1800
11th to 20thNight
40%5%14%31%10%1
1949
21st to endNight
45%411%27%11%1
1980
October1st to 10thNight
50%410%24%11%
1988
11th to 20thNight
59%411%20%5%
2283
21st to endNight
63%5%9%15%8%1
2574
November1st to 10thNight
60%311%18%6%1
2407
11th to 20thNight
63%310%15%8%2
2470
21st to endNight
68%311%14%5%
2626
December1st to 10thNight
78%27%10%3
2818
11th to 20thNight
76%35%11%5%
3454
21st to endNight
72%28%14%3
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
27%23%32%14%21
180
11th to 20thDay
34%22%29%13%2
180
21st to endDay
29%24%30%12%41
188
February1st to 10thDay
42%28%22%7%11
183
11th to 20thDay
32%25%31%8%21
416
21st to endDay
32%22%27%18%2
346
March1st to 10thDay
29%23%27%16%4
420
11th to 20thDay
31%23%25%17%32
420
21st to endDay
32%19%25%14%9%2
462
April1st to 10thDay
37%16%25%13%7%1
420
11th to 20thDay
33%20%24%14%7%3
412
21st to endDay
35%16%29%13%6%2
420
May1st to 10thDay
32%20%26%14%6%1
423
11th to 20thDay
27%16%29%20%6%2
447
21st to endDay
24%21%29%19%6%1
485
June1st to 10thDay
32%16%29%17%6%1
450
11th to 20thDay
22%17%29%23%8%1
450
21st to endDay
24%16%33%18%8%2
450
July1st to 10thDay
20%11%32%26%10%2
445
11th to 20thDay
19%9%39%23%9%2
444
21st to endDay
23%8%32%29%6%1
488
August1st to 10thDay
21%12%26%24%15%2
446
11th to 20thDay
22%8%24%27%17%3
439
21st to endDay
24%13%23%20%13%7%
495
September1st to 10thDay
19%10%32%22%12%6%
450
11th to 20thDay
23%8%22%22%16%8%
450
21st to endDay
21%13%26%24%12%5%
450
October1st to 10thDay
26%16%23%17%14%4
450
11th to 20thDay
33%14%25%15%11%2
387
21st to endDay
41%16%20%17%6%
396
November1st to 10thDay
35%15%27%19%4
365
11th to 20thDay
34%16%26%17%6%1
370
21st to endDay
33%21%26%17%3
212
December1st to 10thDay
39%17%24%14%5%1
180
11th to 20thDay
38%21%29%8%31
180
21st to endDay
41%21%27%9%21
198
January1st to 10thNight
29%20%29%19%3
760
11th to 20thNight
28%19%29%19%4
760
21st to endNight
23%18%30%23%6%1
820
February1st to 10thNight
25%19%31%20%5%
720
11th to 20thNight
24%19%33%20%3
703
21st to endNight
26%18%29%23%4
592
March1st to 10thNight
29%16%30%22%3
720
11th to 20thNight
29%16%28%21%5%1
720
21st to endNight
26%16%26%24%8%1
792
April1st to 10thNight
32%14%24%23%5%
720
11th to 20thNight
29%14%26%24%7%
659
21st to endNight
30%17%26%20%7%
540
May1st to 10thNight
30%11%28%21%9%
523
11th to 20thNight
23%10%27%31%7%1
354
21st to endNight
24%8%27%33%8%
389
June1st to 10thNight
30%8%23%31%8%1
360
11th to 20thNight
22%7%24%33%14%
360
21st to endNight
22%6%23%38%11%1
360
July1st to 10thNight
16%5%28%36%14%1
350
11th to 20thNight
14%5%22%43%13%2
348
21st to endNight
18%5%19%42%16%1
394
August1st to 10thNight
18%415%41%20%1
362
11th to 20thNight
19%5%17%37%20%1
532
21st to endNight
21%421%32%20%2
750
September1st to 10thNight
22%7%21%34%14%2
720
11th to 20thNight
21%6%21%30%21%2
720
21st to endNight
24%8%23%28%15%2
720
October1st to 10thNight
26%11%22%27%14%1
720
11th to 20thNight
30%11%23%25%9%2
720
21st to endNight
34%13%25%23%4
792
November1st to 10thNight
31%14%24%22%8%
740
11th to 20thNight
28%17%27%19%9%1
760
21st to endNight
31%19%22%22%6%1
760
December1st to 10thNight
36%17%25%17%6%
836
11th to 20thNight
32%20%23%19%6%
826
21st to endNight
35%18%23%19%4
836
Page generated at 2024-01-24 09:37:27. Version ac07

Copyright 2024 Attilla Danko


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