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Sulligent
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sulligent clear sky chart from 2005-11-05 to 2017-09-10.

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
49%
15314
25%
46707
18%
15270
57%
15270
30%
28096

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
28%
900
24%
2455
9%
895
41%
895
24%
1584
January16th to endNight
25%
786
26%
2322
11%
786
38%
786
23%
1540
February1st to 15thNight
28%
704
24%
2112
10%
701
40%
701
25%
1331
February16th to endNight
25%
631
25%
1893
10%
631
37%
631
26%
1182
March1st to 15thNight
29%
720
19%
2160
11%
720
37%
720
24%
1397
March16th to endNight
37%
618
25%
2005
16%
618
48%
618
29%
1168
April1st to 15thNight
39%
539
26%
1797
16%
539
52%
539
31%
1016
April16th to endNight
46%
540
26%
1800
20%
540
57%
540
33%
1001
May1st to 15thNight
50%
540
22%
1707
16%
540
57%
540
31%
1016
May16th to endNight
65%
561
23%
1682
19%
561
69%
561
37%
959
June1st to 15thNight
73%
540
20%
1566
18%
540
75%
540
36%
946
June16th to endNight
77%
540
23%
1440
19%
540
79%
540
41%
859
July1st to 15thNight
76%
510
19%
1360
17%
510
77%
510
35%
863
July16th to endNight
78%
564
19%
1672
20%
531
78%
531
33%
985
August1st to 15thNight
78%
539
19%
1788
23%
536
79%
536
33%
1029
August16th to endNight
73%
573
23%
1910
28%
573
73%
573
28%
1165
September1st to 15thNight
67%
550
23%
1775
24%
550
69%
550
32%
1029
September16th to endNight
65%
657
29%
1815
23%
657
68%
657
37%
1070
October1st to 15thNight
60%
660
35%
1824
27%
660
65%
660
42%
1044
October16th to endNight
53%
704
33%
2142
27%
704
60%
704
36%
1197
November1st to 15thNight
51%
700
30%
2276
25%
700
61%
700
35%
1229
November16th to endNight
40%
720
27%
2340
19%
720
53%
720
29%
1368
December1st to 15thNight
37%
720
24%
2340
16%
720
47%
720
24%
1441
December16th to endNight
27%
798
21%
2526
12%
798
38%
798
21%
1677

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
12%5%25%5%35%5%5%7%42%
47895
Night
12%5%2442445%7%47%
46905
TransparencyDay
39%5%10%20%18%4
47596
Night
35%410%21%20%7%
46709
SeeingDay
14%6%18%25%23%12%
5433
Night
15%7%22%28%21%4
15316

By Month

Percentage Cloud Cover SE (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
21%7%35%31323443%
1481
16th to endDay
19%5%2341343446%
1897
February1st to 15thDay
16%7%35%423345%43%
1750
16th to endDay
20%5%23433445%42%
1580
March1st to 15thDay
18%6%35%5%25%445%37%
1800
16th to endDay
14%5%35%42445%7%41%
2225
April1st to 15thDay
12%5%24424447%45%
2151
16th to endDay
11%5%3432435%7%48%
2160
May1st to 15thDay
14%4245%35%5%47%41%
2244
16th to endDay
8%5%35%7%36%5%5%7%41%
2431
June1st to 15thDay
6%425%6%46%6%7%10%37%
2388
16th to endDay
7%315%5%36%6%6%9%44%
2520
July1st to 15thDay
9%426%7%37%6%8%10%32%
2520
16th to endDay
8%325%7%48%8%8%10%33%
2374
August1st to 15thDay
6%5%246%46%7%8%10%36%
2160
16th to endDay
11%5%26%7%46%6%7%8%33%
2292
September1st to 15thDay
10%5%16%5%36%5%6%8%41%
2059
16th to endDay
12%4245%34446%48%
1815
October1st to 15thDay
10%5%2442435%6%50%
1804
16th to endDay
12%313312335%58%
1730
November1st to 15thDay
11%324314345%55%
1582
16th to endDay
16%5%23223446%49%
1620
December1st to 15thDay
20%8%35%433435%38%
1620
16th to endDay
23%8%25%323335%37%
1692
January1st to 15thNight
17%6%24423335%45%
2455
16th to endNight
17%7%36%414435%42%
2322
February1st to 15thNight
17%6%24323345%45%
2103
16th to endNight
17%6%25%423345%45%
1893
March1st to 15thNight
16%7%2442435%6%41%
2160
16th to endNight
13%5%24423346%49%
2005
April1st to 15thNight
11%42442445%7%49%
1797
16th to endNight
10%32332335%7%52%
1800
May1st to 15thNight
11%425%5%2345%7%47%
1706
16th to endNight
6%41443446%9%48%
1682
June1st to 15thNight
4424426%5%8%10%46%
1566
16th to endNight
33225%35%6%6%9%52%
1440
July1st to 15thNight
5%2246%36%7%8%10%42%
1440
16th to endNight
5%314436%6%7%12%42%
1788
August1st to 15thNight
5%313436%6%8%11%45%
1800
16th to endNight
6%415%6%35%5%7%11%42%
1910
September1st to 15thNight
10%42442345%9%48%
1775
16th to endNight
10%4234235%6%8%50%
1815
October1st to 15thNight
9%413413336%57%
1824
16th to endNight
15%41321323457%
2142
November1st to 15thNight
11%324323335%57%
2276
16th to endNight
14%6%2341344351%
2340
December1st to 15thNight
17%6%24324446%44%
2340
16th to endNight
19%7%25%424345%40%
2526

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
45%36%16%23%4
1482
16th to endDay
41%25%23%21%5%
1897
February1st to 15thDay
44%27%22%18%4
1752
16th to endDay
43%37%16%23%5%
1580
March1st to 15thDay
48%38%17%16%5%
1800
16th to endDay
41%411%22%18%1
2226
April1st to 15thDay
37%310%22%18%7%
2151
16th to endDay
35%49%24%23%2
2160
May1st to 15thDay
42%6%9%20%17%4
2244
16th to endDay
40%6%13%23%12%2
2435
June1st to 15thDay
37%8%12%22%16%1
2388
16th to endDay
32%8%13%21%19%3
2520
July1st to 15thDay
41%9%18%19%8%2
2371
16th to endDay
41%9%19%19%9%
2228
August1st to 15thDay
38%10%16%19%12%2
2148
16th to endDay
43%8%14%21%8%3
2292
September1st to 15thDay
40%7%13%20%13%5%
2059
16th to endDay
36%48%21%21%7%
1815
October1st to 15thDay
33%48%19%25%9%
1804
16th to endDay
29%3419%33%10%
1730
November1st to 15thDay
31%36%19%30%9%
1582
16th to endDay
35%36%21%24%8%
1620
December1st to 15thDay
48%46%19%14%6%
1620
16th to endDay
50%38%19%14%2
1692
January1st to 15thNight
41%36%17%25%4
2455
16th to endNight
45%3418%21%6%
2322
February1st to 15thNight
41%26%21%20%6%
2112
16th to endNight
41%25%21%22%6%
1893
March1st to 15thNight
43%39%18%17%8%
2160
16th to endNight
36%39%25%21%4
2005
April1st to 15thNight
33%310%24%20%7%
1797
16th to endNight
31%49%23%25%5%
1800
May1st to 15thNight
35%411%19%21%6%
1707
16th to endNight
28%6%16%25%17%4
1684
June1st to 15thNight
29%8%14%23%20%3
1566
16th to endNight
26%8%15%22%23%3
1440
July1st to 15thNight
31%9%18%24%11%4
1360
16th to endNight
30%9%22%25%11%1
1672
August1st to 15thNight
28%9%18%24%14%3
1788
16th to endNight
33%10%17%23%12%3
1910
September1st to 15thNight
32%6%15%22%14%7%
1775
16th to endNight
31%48%22%23%9%
1815
October1st to 15thNight
28%37%20%25%15%
1824
16th to endNight
31%2314%32%15%
2142
November1st to 15thNight
30%26%18%26%14%
2276
16th to endNight
37%25%18%26%10%
2340
December1st to 15thNight
41%38%21%19%5%
2340
16th to endNight
47%38%19%16%5%
2526

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
24%14%38%16%5%
90
16th to endDay
31%27%26%12%21
96
February1st to 15thDay
21%26%34%15%2
90
16th to endDay
29%18%33%18%
81
March1st to 15thDay
31%25%32%7%21
90
16th to endDay
23%7%30%27%11%
243
April1st to 15thDay
20%12%29%21%14%2
270
16th to endDay
12%9%25%29%20%2
270
May1st to 15thDay
18%7%23%28%13%8%
288
16th to endDay
12%323%27%20%11%
331
June1st to 15thDay
10%112%25%32%17%
363
16th to endDay
8%211%29%28%19%
495
July1st to 15thDay
5%210%32%31%17%
475
16th to endDay
10%6%18%32%31%
352
August1st to 15thDay
8%111%20%34%23%
313
16th to endDay
16%26%26%25%22%
332
September1st to 15thDay
9%47%24%35%18%
294
16th to endDay
12%210%31%35%7%
254
October1st to 15thDay
13%222%31%23%6%
244
16th to endDay
16%5%19%31%23%3
96
November1st to 15thDay
14%13%35%23%13%
90
16th to endDay
17%15%35%20%10%1
90
December1st to 15thDay
32%13%28%20%41
90
16th to endDay
29%18%33%12%6%
96
January1st to 15thNight
22%16%29%22%8%
900
16th to endNight
21%12%36%25%2
786
February1st to 15thNight
21%12%32%27%5%
704
16th to endNight
20%15%35%25%2
631
March1st to 15thNight
21%12%32%27%6%
720
16th to endNight
17%8%31%26%14%
618
April1st to 15thNight
13%11%32%26%14%1
539
16th to endNight
12%6%31%32%15%2
540
May1st to 15thNight
13%425%31%22%2
540
16th to endNight
8%117%34%31%5%
563
June1st to 15thNight
5%10%37%37%7%
540
16th to endNight
49%25%45%14%
540
July1st to 15thNight
416%28%45%13%
510
16th to endNight
6%6%24%41%20%
564
August1st to 15thNight
7%324%48%15%
539
16th to endNight
9%6%25%43%13%
573
September1st to 15thNight
11%110%30%38%7%
550
16th to endNight
11%212%34%35%4
657
October1st to 15thNight
11%319%31%28%4
660
16th to endNight
18%6%18%30%23%2
704
November1st to 15thNight
12%9%22%32%19%3
700
16th to endNight
17%9%29%27%14%1
720
December1st to 15thNight
21%11%26%29%10%
720
16th to endNight
25%12%29%25%6%
798
Page generated at 2017-09-11 18:35:28. Version ac04

Copyright 2017 A. Danko


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