Site d'observation RESPECT
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Site d'observation RESPECT clear sky chart from 2005-11-05 to 2017-09-22.

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
21%
14661
11%
46884
5%
14630
28%
14630
12%
35101

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
10%
723
9%
2521
3%
719
17%
719
5%
2047
January16th to endNight
13%
768
11%
2688
2%
768
24%
768
9%
2011
February1st to 15thNight
13%
703
9%
2356
2%
701
21%
701
8%
1841
February16th to endNight
12%
631
12%
1893
3%
631
22%
631
10%
1483
March1st to 15thNight
15%
720
14%
2139
7%
720
23%
720
12%
1606
March16th to endNight
24%
768
15%
2055
6%
768
31%
768
18%
1521
April1st to 15thNight
18%
694
14%
1772
4%
694
25%
694
15%
1364
April16th to endNight
22%
540
15%
1620
6%
540
29%
540
16%
1179
May1st to 15thNight
28%
489
11%
1569
9%
489
33%
489
14%
1156
May16th to endNight
25%
375
9%
1418
6%
374
34%
374
12%
1045
June1st to 15thNight
30%
360
6%
1260
5%
360
34%
360
12%
952
June16th to endNight
32%
360
7%
1260
6%
360
35%
360
15%
897
July1st to 15thNight
34%
340
7%
1272
7%
340
38%
340
17%
869
July16th to endNight
37%
376
8%
1418
8%
354
40%
354
16%
935
August1st to 15thNight
40%
443
10%
1514
8%
441
44%
441
19%
1047
August16th to endNight
35%
607
15%
1753
7%
607
41%
607
23%
1168
September1st to 15thNight
30%
720
11%
1869
5%
720
33%
720
23%
1334
September16th to endNight
32%
685
17%
1891
9%
685
38%
685
25%
1262
October1st to 15thNight
21%
660
15%
1900
5%
660
31%
660
17%
1371
October16th to endNight
15%
704
8%
2288
3%
704
21%
704
9%
1814
November1st to 15thNight
21%
700
14%
2277
8%
700
28%
700
11%
1691
November16th to endNight
19%
745
11%
2571
6%
745
26%
745
9%
1967
December1st to 15thNight
8%
750
5%
2700
1%
750
13%
750
5%
2240
December16th to endNight
10%
800
8%
2880
2%
800
17%
800
5%
2301

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%11%47%5%34445%27%
48001
Night
19%12%47%6%34445%28%
47051
TransparencyDay
58%6%10%16%7%
47686
Night
56%6%11%17%7%
46884
SeeingDay
25%16%30%18%7%1
6246
Night
23%18%30%20%6%
14662

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%9%9%44335%19%
1416
16th to endDay
10%14%7%10%8%35%45%5%24%
1536
February1st to 15thDay
11%15%7%10%9%45%44421%
1501
16th to endDay
14%16%6%10%8%3434423%
1580
March1st to 15thDay
17%14%5%9%5%3434427%
1811
16th to endDay
16%10%5%8%6%25%44429%
2168
April1st to 15thDay
23%13%36%423335%29%
2176
16th to endDay
22%12%25%423345%32%
2340
May1st to 15thDay
24%9%36%5%24336%29%
2391
16th to endDay
24%9%46%6%3445%5%25%
2696
June1st to 15thDay
25%8%25%5%35%5%6%6%25%
2700
16th to endDay
24%8%37%6%45%45%5%23%
2700
July1st to 15thDay
18%7%36%5%346%6%8%29%
2609
16th to endDay
22%7%26%5%36%5%5%6%27%
2654
August1st to 15thDay
20%8%36%6%36%46%6%25%
2424
16th to endDay
17%6%26%425%45%7%37%
2447
September1st to 15thDay
24%8%25%323336%37%
2091
16th to endDay
22%6%24422345%41%
1881
October1st to 15thDay
23%13%37%323435%29%
1728
16th to endDay
29%14%27%5%2433421%
1584
November1st to 15thDay
20%16%46%5%3334426%
1581
16th to endDay
22%18%48%41234425%
1383
December1st to 15thDay
23%19%6%8%6%2433318%
1260
16th to endDay
22%17%7%8%6%2423320%
1344
January1st to 15thNight
17%16%7%9%9%46%32419%
2521
16th to endNight
11%13%6%10%7%46%5%5%5%23%
2688
February1st to 15thNight
9%13%6%10%10%5%5%5%4423%
2355
16th to endNight
15%18%6%9%7%3433423%
1893
March1st to 15thNight
18%13%47%5%3443428%
2126
16th to endNight
15%11%48%6%34345%32%
2055
April1st to 15thNight
23%14%46%42344427%
1772
16th to endNight
24%9%35%42334433%
1620
May1st to 15thNight
23%10%45%43445%330%
1569
16th to endNight
25%6%36%7%34335%29%
1416
June1st to 15thNight
25%9%35%5%45%445%27%
1260
16th to endNight
17%7%47%435%45%7%30%
1260
July1st to 15thNight
17%7%36%425%6%5%8%32%
1349
16th to endNight
17%7%25%5%35%5%48%34%
1514
August1st to 15thNight
17%5%26%5%35%5%5%7%33%
1524
16th to endNight
18%5%15%5%345%5%8%36%
1753
September1st to 15thNight
22%7%24424445%36%
1869
16th to endNight
23%5%2331233445%
1891
October1st to 15thNight
21%11%36%423345%34%
1900
16th to endNight
26%14%445%35%33424%
2288
November1st to 15thNight
20%11%36%6%35%445%28%
2277
16th to endNight
20%14%5%9%5%3333425%
2571
December1st to 15thNight
22%18%7%10%7%3332417%
2700
16th to endNight
21%18%6%8%6%3333321%
2880

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
67%5%7%11%6%
1417
16th to endDay
60%5%8%17%7%
1536
February1st to 15thDay
67%410%10%6%
1504
16th to endDay
65%47%13%7%1
1580
March1st to 15thDay
61%39%12%11%1
1821
16th to endDay
57%48%16%10%1
2168
April1st to 15thDay
58%48%16%8%2
2176
16th to endDay
54%49%16%13%2
2340
May1st to 15thDay
57%5%9%16%10%
2391
16th to endDay
60%7%9%17%5%
2700
June1st to 15thDay
58%7%12%15%5%1
2700
16th to endDay
61%7%11%14%6%
2700
July1st to 15thDay
51%10%14%17%6%
2457
16th to endDay
58%9%11%15%5%
2487
August1st to 15thDay
56%9%16%14%2
2410
16th to endDay
46%8%15%23%6%
2447
September1st to 15thDay
50%5%13%20%10%
2091
16th to endDay
44%5%13%24%11%
1881
October1st to 15thDay
58%411%18%6%
1728
16th to endDay
66%5%9%14%4
1584
November1st to 15thDay
61%6%10%15%6%
1581
16th to endDay
64%5%9%15%4
1383
December1st to 15thDay
70%5%9%11%2
1260
16th to endDay
69%46%11%7%
1344
January1st to 15thNight
68%5%7%11%6%
2521
16th to endNight
57%7%9%17%7%
2688
February1st to 15thNight
61%7%9%14%7%
2356
16th to endNight
63%47%14%9%
1893
March1st to 15thNight
56%5%8%17%9%2
2139
16th to endNight
52%5%10%18%10%1
2055
April1st to 15thNight
57%5%6%17%10%2
1772
16th to endNight
53%5%8%16%13%2
1620
May1st to 15thNight
55%6%10%16%11%
1569
16th to endNight
56%7%10%15%9%
1418
June1st to 15thNight
58%7%10%16%6%
1260
16th to endNight
51%7%14%17%8%
1260
July1st to 15thNight
46%10%16%19%7%
1272
16th to endNight
47%7%17%19%7%
1418
August1st to 15thNight
45%10%18%22%2
1514
16th to endNight
41%9%19%25%5%
1753
September1st to 15thNight
46%6%13%22%8%1
1869
16th to endNight
41%5%15%26%9%
1891
October1st to 15thNight
51%5%11%22%8%
1900
16th to endNight
62%7%9%15%4
2288
November1st to 15thNight
55%7%13%15%7%
2277
16th to endNight
60%6%10%16%5%
2571
December1st to 15thNight
70%5%9%10%3
2700
16th to endNight
67%5%9%11%7%
2880

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
20%30%45%5%
60
16th to endDay
17%29%40%7%31
64
February1st to 15thDay
19%23%31%19%5%
147
16th to endDay
22%20%36%15%4
239
March1st to 15thDay
25%24%29%15%4
270
16th to endDay
19%23%23%21%10%2
288
April1st to 15thDay
30%21%28%12%6%1
270
16th to endDay
25%20%31%15%33
270
May1st to 15thDay
32%12%32%14%5%1
288
16th to endDay
24%18%33%17%4
409
June1st to 15thDay
30%11%31%18%7%
495
16th to endDay
26%11%30%23%7%
495
July1st to 15thDay
23%10%36%19%10%
391
16th to endDay
25%9%32%26%5%
326
August1st to 15thDay
20%10%33%23%9%2
313
16th to endDay
19%15%28%20%12%3
332
September1st to 15thDay
23%13%29%19%10%3
315
16th to endDay
19%13%32%16%14%3
278
October1st to 15thDay
29%15%27%17%8%2
244
16th to endDay
34%20%24%13%6%
240
November1st to 15thDay
28%20%25%17%6%
235
16th to endDay
31%18%22%19%6%
153
December1st to 15thDay
41%20%28%6%3
60
16th to endDay
35%40%20%3
64
January1st to 15thNight
22%29%32%13%1
723
16th to endNight
16%24%37%16%3
768
February1st to 15thNight
13%25%39%17%3
704
16th to endNight
25%20%33%15%4
631
March1st to 15thNight
24%21%36%14%3
720
16th to endNight
18%19%30%22%7%1
768
April1st to 15thNight
26%19%29%17%6%
694
16th to endNight
28%12%31%19%7%
540
May1st to 15thNight
25%14%26%22%9%1
489
16th to endNight
27%12%27%24%8%
375
June1st to 15thNight
27%7%26%30%8%
360
16th to endNight
18%9%34%28%8%
360
July1st to 15thNight
17%7%35%26%12%
340
16th to endNight
17%5%31%35%9%1
376
August1st to 15thNight
18%5%26%29%18%1
443
16th to endNight
19%8%31%29%9%2
607
September1st to 15thNight
23%9%29%25%10%1
720
16th to endNight
22%11%30%23%11%
685
October1st to 15thNight
23%17%31%18%6%1
660
16th to endNight
29%21%28%14%6%
704
November1st to 15thNight
24%24%25%20%4
700
16th to endNight
26%21%26%17%6%1
745
December1st to 15thNight
28%25%30%12%3
750
16th to endNight
31%25%25%14%3
800
Page generated at 2017-09-23 06:43:44. Version ac04

Copyright 2017 A. Danko


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