Luling Skies Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Luling Skies Observatory clear sky chart from 2005-11-05 to 2017-09-20.

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
61%
15098
23%
47027
20%
15056
66%
15056
32%
27917

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
44%
895
22%
2324
11%
892
51%
892
33%
1494
January16th to endNight
41%
807
26%
2343
14%
807
48%
807
28%
1504
February1st to 15thNight
45%
704
26%
2112
14%
701
53%
701
31%
1272
February16th to endNight
40%
631
23%
1893
12%
631
46%
631
28%
1188
March1st to 15thNight
43%
594
25%
2034
17%
594
52%
594
26%
1222
March16th to endNight
59%
576
24%
2052
21%
576
65%
576
31%
1126
April1st to 15thNight
56%
539
26%
1797
22%
539
64%
539
32%
1015
April16th to endNight
60%
540
26%
1800
26%
540
66%
540
34%
987
May1st to 15thNight
66%
539
21%
1799
21%
539
71%
539
34%
998
May16th to endNight
74%
561
22%
1870
24%
561
77%
561
35%
1042
June1st to 15thNight
78%
540
14%
1776
17%
540
78%
540
32%
1035
June16th to endNight
77%
540
14%
1620
16%
540
78%
540
30%
1014
July1st to 15thNight
84%
510
14%
1530
17%
510
84%
510
33%
927
July16th to endNight
80%
564
10%
1740
13%
531
80%
531
26%
1119
August1st to 15thNight
85%
539
15%
1788
18%
536
85%
536
34%
1019
August16th to endNight
76%
573
13%
1910
15%
573
76%
573
25%
1228
September1st to 15thNight
75%
540
20%
1800
23%
540
75%
540
28%
1099
September16th to endNight
76%
634
27%
1827
24%
634
77%
634
34%
1122
October1st to 15thNight
76%
660
32%
1925
28%
660
78%
660
48%
997
October16th to endNight
62%
704
33%
2112
28%
704
67%
704
42%
1134
November1st to 15thNight
65%
700
32%
2100
29%
700
69%
700
37%
1190
November16th to endNight
55%
720
33%
2267
26%
720
64%
720
36%
1256
December1st to 15thNight
51%
720
25%
2304
21%
720
57%
720
28%
1401
December16th to endNight
42%
768
21%
2304
15%
768
47%
768
24%
1528

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
10%5%36%6%36%5%6%8%36%
47766
Night
8%4244245%5%9%47%
47238
TransparencyDay
42%7%12%17%14%5%
47480
Night
32%7%14%20%17%7%
47029
SeeingDay
11%211%21%29%23%
5254
Night
11%316%30%29%9%
15103

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
13%5%25%5%35%35%7%41%
1611
16th to endDay
17%6%35%43344442%
1875
February1st to 15thDay
12%7%2442445%8%43%
1750
16th to endDay
15%6%36%435%35%6%39%
1580
March1st to 15thDay
14%6%25%6%25%447%39%
1936
16th to endDay
10%6%25%425%5%48%44%
2170
April1st to 15thDay
10%435%5%35%5%6%8%41%
2151
16th to endDay
9%425%6%45%5%5%10%40%
2160
May1st to 15thDay
9%425%6%36%5%7%9%39%
2151
16th to endDay
8%425%7%47%5%6%9%37%
2244
June1st to 15thDay
7%5%39%8%49%8%6%9%24%
2178
16th to endDay
6%6%38%10%6%8%9%8%10%22%
2340
July1st to 15thDay
8%6%46%9%6%9%8%8%9%22%
2340
16th to endDay
8%6%37%10%5%11%8%9%7%19%
2306
August1st to 15thDay
8%6%48%8%5%8%7%9%10%21%
2160
16th to endDay
11%8%38%7%5%7%7%8%8%23%
2292
September1st to 15thDay
10%6%36%7%5%8%7%7%9%28%
2160
16th to endDay
9%5%37%7%35%5%6%7%38%
1889
October1st to 15thDay
7%225%5%3445%7%51%
1702
16th to endDay
7%32432445%7%54%
1760
November1st to 15thDay
7%5%15%5%2445%7%49%
1758
16th to endDay
8%4245%14446%53%
1689
December1st to 15thDay
13%6%25%4345%5%6%41%
1647
16th to endDay
19%7%36%6%24446%35%
1917
January1st to 15thNight
13%5%2342345%8%45%
2324
16th to endNight
15%6%23423346%44%
2343
February1st to 15thNight
12%425%42435%8%47%
2103
16th to endNight
16%5%2442335%5%45%
1893
March1st to 15thNight
12%5%25%5%2445%7%44%
2034
16th to endNight
8%5%2342445%7%51%
2052
April1st to 15thNight
9%42432345%6%51%
1797
16th to endNight
5%414425%46%9%51%
1800
May1st to 15thNight
6%315%3345%6%11%48%
1799
16th to endNight
5%3144245%5%9%52%
1869
June1st to 15thNight
4423335%6%8%13%43%
1776
16th to endNight
5%334425%6%9%11%43%
1620
July1st to 15thNight
3322426%6%8%15%44%
1620
16th to endNight
4335%6%36%7%8%14%37%
1859
August1st to 15thNight
3214425%6%10%14%44%
1800
16th to endNight
7%4245%36%6%7%11%38%
1910
September1st to 15thNight
6%4146%45%6%7%10%42%
1800
16th to endNight
7%3243346%6%10%47%
1827
October1st to 15thNight
4313313347%63%
1925
16th to endNight
9%313323337%59%
2112
November1st to 15thNight
8%413424346%54%
2100
16th to endNight
8%324424335%57%
2267
December1st to 15thNight
11%6%245%24437%45%
2304
16th to endNight
15%7%35%425%447%38%
2304

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
41%48%16%19%8%
1612
16th to endDay
44%45%16%20%9%
1875
February1st to 15thDay
37%5%9%16%21%9%
1752
16th to endDay
43%5%8%17%18%6%
1580
March1st to 15thDay
41%6%9%20%17%5%
1936
16th to endDay
37%5%10%21%19%5%
2172
April1st to 15thDay
37%7%12%17%17%8%
2151
16th to endDay
36%6%12%22%16%5%
2160
May1st to 15thDay
37%7%13%20%13%7%
2151
16th to endDay
36%8%13%22%16%1
2248
June1st to 15thDay
47%10%14%17%9%
2178
16th to endDay
48%11%17%15%7%
2340
July1st to 15thDay
49%12%18%15%3
2201
16th to endDay
54%11%17%12%2
2162
August1st to 15thDay
50%12%20%13%3
2148
16th to endDay
53%11%17%10%5%1
2292
September1st to 15thDay
46%10%16%13%10%3
2160
16th to endDay
43%7%13%14%16%5%
1889
October1st to 15thDay
29%5%11%17%22%14%
1702
16th to endDay
28%47%16%27%16%
1760
November1st to 15thDay
31%48%22%24%8%
1758
16th to endDay
30%5%7%17%24%15%
1689
December1st to 15thDay
41%5%10%21%14%5%
1647
16th to endDay
49%5%8%17%14%4
1917
January1st to 15thNight
37%49%16%21%10%
2324
16th to endNight
41%36%15%20%12%
2343
February1st to 15thNight
35%48%19%20%11%
2112
16th to endNight
39%47%15%20%12%
1893
March1st to 15thNight
38%5%10%18%19%7%
2034
16th to endNight
32%413%21%21%7%
2052
April1st to 15thNight
31%6%12%21%17%10%
1797
16th to endNight
30%5%12%25%19%6%
1800
May1st to 15thNight
28%7%13%26%16%7%
1800
16th to endNight
27%8%15%27%19%1
1871
June1st to 15thNight
29%9%20%25%14%
1776
16th to endNight
32%11%24%22%10%
1620
July1st to 15thNight
26%14%31%23%4
1530
16th to endNight
33%14%30%18%2
1740
August1st to 15thNight
23%13%32%24%4
1788
16th to endNight
36%11%28%15%5%2
1910
September1st to 15thNight
33%10%20%17%13%4
1800
16th to endNight
30%9%15%20%17%6%
1827
October1st to 15thNight
21%5%11%22%22%17%
1925
16th to endNight
26%37%15%27%18%
2112
November1st to 15thNight
30%48%21%25%9%
2100
16th to endNight
30%46%18%24%16%
2267
December1st to 15thNight
38%49%24%17%6%
2304
16th to endNight
45%39%19%14%6%
2304

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
18%6%25%35%12%1
90
16th to endDay
19%11%38%23%6%
96
February1st to 15thDay
6%11%33%32%12%4
90
16th to endDay
9%7%33%33%14%1
81
March1st to 15thDay
21%10%36%24%7%
90
16th to endDay
18%5%21%26%23%3
156
April1st to 15thDay
12%5%24%35%19%2
270
16th to endDay
12%219%30%29%6%
270
May1st to 15thDay
11%313%36%27%8%
288
16th to endDay
8%12%27%28%22%
331
June1st to 15thDay
10%421%32%29%
333
16th to endDay
7%6%20%35%29%
495
July1st to 15thDay
6%212%37%39%
475
16th to endDay
8%9%34%46%
355
August1st to 15thDay
12%27%28%48%
313
16th to endDay
12%49%32%40%
332
September1st to 15thDay
11%1318%32%32%
315
16th to endDay
11%217%41%25%
270
October1st to 15thDay
2211%28%40%14%
142
16th to endDay
13%312%33%26%11%
96
November1st to 15thDay
16%318%27%27%5%
90
16th to endDay
8%7%26%31%18%6%
90
December1st to 15thDay
20%326%32%14%3
90
16th to endDay
26%7%27%25%14%
96
January1st to 15thNight
16%7%26%40%9%1
897
16th to endNight
19%8%26%36%9%
807
February1st to 15thNight
14%5%29%37%11%
704
16th to endNight
18%7%29%34%8%
631
March1st to 15thNight
13%7%30%32%14%
594
16th to endNight
10%5%19%37%25%1
576
April1st to 15thNight
12%5%21%40%19%
539
16th to endNight
9%322%38%23%2
540
May1st to 15thNight
8%116%41%31%1
540
16th to endNight
8%8%32%41%7%
563
June1st to 15thNight
6%1223%54%11%
540
16th to endNight
7%316%47%24%
540
July1st to 15thNight
417%48%38%
510
16th to endNight
417%48%35%
564
August1st to 15thNight
38%48%37%
539
16th to endNight
8%1311%42%32%
573
September1st to 15thNight
9%413%46%25%
540
16th to endNight
9%326%47%13%
634
October1st to 15thNight
6%9%35%40%6%
660
16th to endNight
10%218%30%31%5%
704
November1st to 15thNight
10%215%39%28%3
700
16th to endNight
10%324%37%22%1
720
December1st to 15thNight
14%6%21%36%20%1
720
16th to endNight
19%7%25%33%14%
768
Page generated at 2017-09-21 06:18:20. Version ac04

Copyright 2017 A. Danko


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