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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 2018-01-12.

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%
15819
25%
48238
18%
15775
57%
15775
30%
28995

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%
956
23%
2611
9%
951
40%
951
25%
1681
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
66%
568
23%
1828
23%
568
68%
568
32%
1069
September16th to endNight
67%
717
31%
1980
25%
717
70%
717
39%
1142
October1st to 15thNight
60%
720
33%
1990
26%
720
65%
720
42%
1133
October16th to endNight
52%
768
34%
2337
27%
768
61%
768
36%
1295
November1st to 15thNight
51%
760
29%
2471
25%
760
60%
760
34%
1359
November16th to endNight
42%
780
29%
2535
20%
780
55%
780
30%
1455
December1st to 15thNight
37%
780
24%
2535
16%
780
48%
780
25%
1561
December16th to endNight
28%
865
20%
2737
12%
865
38%
865
20%
1843

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%
49074
Night
12%5%2442445%7%47%
48436
TransparencyDay
39%5%10%20%18%4
48775
Night
35%410%21%20%7%
48240
SeeingDay
14%6%18%25%22%11%
5837
Night
15%7%22%28%21%4
15821

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%31323442%
1569
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
11%5%16%5%36%5%6%7%40%
2118
16th to endDay
11%4245%34446%48%
1980
October1st to 15thDay
10%42442435%5%51%
1968
16th to endDay
11%31331233459%
1887
November1st to 15thDay
11%424414345%53%
1717
16th to endDay
15%5%23223446%49%
1755
December1st to 15thDay
19%8%35%423335%39%
1755
16th to endDay
23%8%25%323435%36%
1833
January1st to 15thNight
17%6%24423335%46%
2611
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
11%42432345%9%47%
1828
16th to endNight
9%31332346%8%51%
1980
October1st to 15thNight
9%413313336%58%
1990
16th to endNight
14%41221323458%
2337
November1st to 15thNight
11%324323345%55%
2471
16th to endNight
13%6%2331344352%
2535
December1st to 15thNight
16%6%24324446%44%
2535
16th to endNight
19%7%26%424345%38%
2737

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
1570
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
41%6%13%19%13%5%
2118
16th to endDay
36%5%9%22%19%7%
1980
October1st to 15thDay
32%48%20%24%8%
1968
16th to endDay
29%3419%34%9%
1887
November1st to 15thDay
32%46%18%29%8%
1717
16th to endDay
34%36%21%24%9%
1755
December1st to 15thDay
47%36%19%15%6%
1755
16th to endDay
51%38%20%13%2
1833
January1st to 15thNight
41%36%18%25%4
2611
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
33%6%15%22%14%7%
1828
16th to endNight
29%5%9%24%22%8%
1980
October1st to 15thNight
27%46%23%24%13%
1990
16th to endNight
31%2414%33%14%
2337
November1st to 15thNight
31%37%18%25%13%
2471
16th to endNight
35%25%17%26%11%
2535
December1st to 15thNight
40%38%20%20%5%
2535
16th to endNight
48%37%19%15%5%
2737

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
26%15%35%18%4
123
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
11%47%22%34%18%
315
16th to endDay
10%29%31%35%10%
314
October1st to 15thDay
14%123%30%23%5%
303
16th to endDay
15%10%24%27%19%2
144
November1st to 15thDay
15%9%40%22%10%
135
16th to endDay
14%14%33%22%13%2
135
December1st to 15thDay
28%14%31%18%5%1
135
16th to endDay
29%18%34%13%4
144
January1st to 15thNight
22%16%29%22%8%
956
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
12%110%29%37%7%
568
16th to endNight
10%211%32%37%5%
717
October1st to 15thNight
11%319%30%29%4
720
16th to endNight
18%6%19%30%23%2
768
November1st to 15thNight
12%9%23%32%19%3
760
16th to endNight
17%9%28%27%15%1
780
December1st to 15thNight
21%11%27%29%10%
780
16th to endNight
24%12%29%26%6%
865
Page generated at 2018-01-12 21:01:28. Version ac04

Copyright 2018 A. Danko


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