Camp Les Sommets
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camp Les Sommets clear sky chart from 2005-11-05 to 2017-03-24.

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%
14177
11%
45290
7%
14146
32%
14146
13%
34477

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 15thNight
14%
720
6%
2506
4%
716
17%
716
6%
2097
January16th to endNight
16%
768
7%
2688
4%
768
21%
768
6%
2226
February1st to 15thNight
17%
704
6%
2303
3%
701
20%
701
6%
1952
February16th to endNight
18%
631
9%
1893
5%
631
24%
631
9%
1536
March1st to 15thNight
21%
720
13%
2160
8%
720
26%
720
11%
1693
March16th to endNight
26%
740
17%
1946
7%
740
33%
740
17%
1469
April1st to 15thNight
22%
658
14%
1646
4%
658
29%
658
16%
1295
April16th to endNight
26%
531
16%
1521
6%
531
34%
531
19%
1072
May1st to 15thNight
28%
429
15%
1419
10%
429
36%
429
17%
987
May16th to endNight
30%
342
11%
1369
10%
342
38%
342
13%
964
June1st to 15thNight
32%
330
9%
1320
9%
330
39%
330
11%
968
June16th to endNight
43%
330
8%
1320
11%
330
47%
330
17%
872
July1st to 15thNight
47%
310
11%
1240
16%
310
51%
310
18%
787
July16th to endNight
52%
348
10%
1306
13%
326
53%
326
19%
816
August1st to 15thNight
52%
387
13%
1368
14%
385
54%
385
19%
916
August16th to endNight
54%
640
17%
1690
10%
640
56%
640
31%
1105
September1st to 15thNight
44%
660
11%
1680
6%
660
46%
660
24%
1188
September16th to endNight
42%
657
19%
1815
13%
657
45%
657
29%
1166
October1st to 15thNight
30%
660
15%
1891
9%
660
37%
660
18%
1385
October16th to endNight
22%
704
8%
2288
5%
704
27%
704
10%
1804
November1st to 15thNight
22%
700
13%
2277
9%
700
28%
700
11%
1733
November16th to endNight
21%
720
12%
2436
9%
720
26%
720
10%
1915
December1st to 15thNight
13%
720
4%
2520
0%
720
16%
720
5%
2185
December16th to endNight
10%
768
6%
2688
3%
768
14%
768
3%
2346

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
19%11%47%6%34445%27%
45653
Night
18%12%5%8%6%34445%27%
45460
TransparencyDay
58%5%10%16%7%
45341
Night
59%5%9%16%7%
45290
SeeingDay
27%13%26%19%10%3
4992
Night
26%13%26%23%9%
14178

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 15thDay
17%16%6%13%8%5%6%5%3312%
1432
16th to endDay
11%15%7%11%10%46%5%4418%
1536
February1st to 15thDay
12%16%10%14%9%5%7%43313%
1558
16th to endDay
12%18%7%11%9%5%433418%
1580
March1st to 15thDay
16%15%6%8%7%25%44423%
1790
16th to endDay
17%13%5%10%5%3322431%
2122
April1st to 15thDay
20%13%6%6%5%2432429%
1972
16th to endDay
20%9%35%6%34445%33%
2109
May1st to 15thDay
21%7%36%6%34346%31%
2210
16th to endDay
21%7%35%7%345%5%7%27%
2394
June1st to 15thDay
30%6%35%5%2445%6%24%
2310
16th to endDay
20%7%36%425%5%5%7%30%
2310
July1st to 15thDay
17%5%37%5%35%5%6%9%31%
2310
16th to endDay
17%7%35%5%46%6%7%8%27%
2458
August1st to 15thDay
18%7%37%7%45%5%5%7%27%
2241
16th to endDay
16%6%245%2446%8%37%
2158
September1st to 15thDay
20%6%2443335%5%39%
1949
16th to endDay
18%6%34423446%39%
1815
October1st to 15thDay
23%11%26%6%32346%29%
1737
16th to endDay
24%18%35%5%2433422%
1584
November1st to 15thDay
19%14%37%5%2435%5%26%
1581
16th to endDay
17%16%6%8%5%2434424%
1521
December1st to 15thDay
20%20%7%10%6%3334315%
1440
16th to endDay
22%20%8%12%6%3432212%
1536
January1st to 15thNight
14%17%7%13%8%36%44415%
2506
16th to endNight
10%16%8%11%10%5%7%43416%
2688
February1st to 15thNight
11%14%7%16%10%46%44316%
2302
16th to endNight
14%16%8%11%6%5%5%32422%
1893
March1st to 15thNight
18%14%5%7%7%34435%25%
2147
16th to endNight
16%12%6%7%6%3423333%
1946
April1st to 15thNight
21%13%46%7%3443328%
1646
16th to endNight
20%9%45%433336%36%
1521
May1st to 15thNight
18%9%36%4245%37%33%
1419
16th to endNight
20%6%46%5%35%45%6%31%
1367
June1st to 15thNight
29%6%35%43345%7%26%
1320
16th to endNight
19%6%24425%6%6%8%34%
1320
July1st to 15thNight
14%6%36%435%5%6%9%35%
1320
16th to endNight
12%5%25%5%35%5%6%8%38%
1402
August1st to 15thNight
15%6%16%435%5%6%8%35%
1378
16th to endNight
13%415%33445%8%45%
1690
September1st to 15thNight
19%5%16%4235%46%39%
1680
16th to endNight
20%423313347%45%
1815
October1st to 15thNight
22%9%36%423445%33%
1891
16th to endNight
26%12%37%5%34345%23%
2288
November1st to 15thNight
18%12%46%7%44346%25%
2277
16th to endNight
19%14%6%10%5%3433325%
2436
December1st to 15thNight
21%19%8%11%7%2433414%
2520
16th to endNight
20%20%9%10%7%35%33312%
2688

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 15thDay
75%5%6%9%2
1433
16th to endDay
68%49%13%3
1536
February1st to 15thDay
77%36%10%2
1561
16th to endDay
69%47%9%7%1
1580
March1st to 15thDay
64%410%13%6%1
1800
16th to endDay
59%38%17%9%1
2122
April1st to 15thDay
60%37%16%10%2
1972
16th to endDay
52%5%7%18%12%3
2109
May1st to 15thDay
53%5%8%20%11%
2210
16th to endDay
54%8%9%17%8%
2398
June1st to 15thDay
60%6%10%15%6%
2310
16th to endDay
52%7%10%20%7%
2310
July1st to 15thDay
46%7%14%23%7%
2161
16th to endDay
51%9%14%20%4
2291
August1st to 15thDay
54%8%15%16%3
2227
16th to endDay
43%7%15%23%10%
2158
September1st to 15thDay
46%6%12%25%9%
1949
16th to endDay
43%5%12%25%12%
1815
October1st to 15thDay
56%411%19%7%
1737
16th to endDay
65%410%14%4
1584
November1st to 15thDay
59%5%11%13%7%1
1581
16th to endDay
62%5%11%13%6%
1521
December1st to 15thDay
73%5%8%9%2
1440
16th to endDay
79%45%5%4
1536
January1st to 15thNight
72%49%10%2
2506
16th to endNight
71%5%6%12%4
2688
February1st to 15thNight
72%5%7%11%3
2303
16th to endNight
67%47%11%8%
1893
March1st to 15thNight
63%47%17%6%1
2160
16th to endNight
57%38%16%12%2
1946
April1st to 15thNight
60%36%16%12%
1646
16th to endNight
50%48%19%14%2
1521
May1st to 15thNight
50%6%7%18%15%1
1419
16th to endNight
52%8%9%20%8%1
1369
June1st to 15thNight
58%6%8%19%6%
1320
16th to endNight
45%8%12%23%8%
1320
July1st to 15thNight
40%10%14%24%8%
1240
16th to endNight
41%8%17%23%9%
1306
August1st to 15thNight
44%8%17%22%5%
1368
16th to endNight
37%7%17%26%11%
1690
September1st to 15thNight
45%6%13%24%8%
1680
16th to endNight
38%5%14%28%12%
1815
October1st to 15thNight
53%5%10%20%9%
1891
16th to endNight
63%5%10%15%5%
2288
November1st to 15thNight
60%411%14%6%1
2277
16th to endNight
64%48%15%5%
2436
December1st to 15thNight
75%5%7%9%1
2520
16th to endNight
78%45%7%3
2688

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 15thDay
21%20%31%18%8%
60
16th to endDay
34%17%31%14%11
64
February1st to 15thDay
27%25%27%14%5%
136
16th to endDay
26%21%26%19%41
239
March1st to 15thDay
32%20%23%19%4
270
16th to endDay
27%16%24%16%11%3
260
April1st to 15thDay
34%15%24%17%5%2
210
16th to endDay
25%15%29%14%11%3
210
May1st to 15thDay
30%11%29%14%10%2
228
16th to endDay
24%13%29%23%7%1
267
June1st to 15thDay
37%12%21%19%9%
255
16th to endDay
21%11%33%22%9%1
255
July1st to 15thDay
20%8%31%23%11%3
245
16th to endDay
17%9%33%25%12%1
270
August1st to 15thDay
23%7%29%18%16%3
253
16th to endDay
22%6%19%24%19%8%
268
September1st to 15thDay
20%5%25%21%16%10%
255
16th to endDay
20%12%20%22%13%11%
254
October1st to 15thDay
30%13%22%13%16%3
253
16th to endDay
40%13%20%17%8%
240
November1st to 15thDay
29%14%27%20%6%2
235
16th to endDay
34%17%19%15%9%2
141
December1st to 15thDay
43%16%21%13%13
60
16th to endDay
46%17%29%6%
64
January1st to 15thNight
26%19%30%19%3
720
16th to endNight
22%19%31%20%5%
768
February1st to 15thNight
20%19%32%24%3
704
16th to endNight
26%16%30%21%4
631
March1st to 15thNight
31%15%26%21%4
720
16th to endNight
23%18%26%21%8%1
740
April1st to 15thNight
29%16%25%23%5%
658
16th to endNight
27%14%27%21%8%
531
May1st to 15thNight
24%9%31%24%8%1
429
16th to endNight
23%8%29%29%8%
343
June1st to 15thNight
34%6%20%28%10%
330
16th to endNight
17%6%28%35%11%
330
July1st to 15thNight
16%325%32%21%
310
16th to endNight
13%225%41%17%
348
August1st to 15thNight
20%316%39%19%1
387
16th to endNight
17%221%35%21%1
640
September1st to 15thNight
22%8%20%32%15%1
660
16th to endNight
22%7%25%24%17%1
657
October1st to 15thNight
30%9%24%21%13%1
660
16th to endNight
35%12%25%20%4
704
November1st to 15thNight
26%15%29%20%7%1
700
16th to endNight
29%18%25%15%9%2
720
December1st to 15thNight
35%17%27%15%4
720
16th to endNight
36%17%23%17%3
768
Page generated at 2017-03-25 12:39:47. Version ac04

Copyright 2017 A. Danko


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