Louisiana Delta Community College
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Louisiana Delta Community College clear sky chart from 2005-11-05 to 2017-04-08.

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
53%
15017
25%
45526
19%
14971
59%
14971
33%
26812

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
36%
900
25%
2327
12%
895
44%
895
32%
1501
January16th to endNight
30%
960
26%
2496
10%
960
39%
960
29%
1665
February1st to 15thNight
35%
794
24%
2202
9%
791
45%
791
30%
1408
February16th to endNight
28%
609
27%
1871
11%
609
41%
609
26%
1176
March1st to 15thNight
37%
540
24%
1980
16%
540
48%
540
24%
1179
March16th to endNight
45%
576
22%
2106
18%
576
53%
576
28%
1204
April1st to 15thNight
43%
518
27%
1727
18%
518
56%
518
34%
946
April16th to endNight
46%
495
26%
1650
22%
495
56%
495
31%
936
May1st to 15thNight
52%
495
22%
1650
19%
495
59%
495
29%
975
May16th to endNight
65%
515
24%
1595
26%
513
68%
513
37%
890
June1st to 15thNight
79%
495
21%
1485
23%
495
82%
495
43%
796
June16th to endNight
76%
495
22%
1485
24%
495
77%
495
38%
844
July1st to 15thNight
76%
465
20%
1395
22%
465
77%
465
37%
800
July16th to endNight
84%
522
20%
1468
24%
489
84%
489
42%
808
August1st to 15thNight
86%
494
23%
1587
28%
491
86%
491
43%
819
August16th to endNight
76%
525
21%
1750
27%
525
76%
525
31%
1030
September1st to 15thNight
72%
495
25%
1650
28%
495
73%
495
32%
964
September16th to endNight
69%
561
31%
1792
30%
561
71%
561
36%
1000
October1st to 15thNight
63%
660
31%
1980
25%
660
66%
660
40%
1078
October16th to endNight
59%
704
36%
2112
27%
704
67%
704
42%
1136
November1st to 15thNight
55%
700
32%
2100
25%
700
61%
700
40%
1157
November16th to endNight
45%
720
32%
2225
22%
720
55%
720
34%
1287
December1st to 15thNight
39%
819
24%
2397
15%
819
47%
819
28%
1521
December16th to endNight
36%
960
21%
2496
11%
960
42%
960
27%
1692

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%45%7%42%
45710
Night
11%42442345%7%49%
45724
TransparencyDay
39%410%20%18%5%
45411
Night
34%410%20%21%8%
45528
SeeingDay
11%415%23%30%14%
4848
Night
14%421%32%23%4
15017

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
20%6%2342234445%
1611
16th to endDay
20%7%3441322445%
1728
February1st to 15thDay
18%6%35%32333444%
1657
16th to endDay
18%7%25%5%1333443%
1612
March1st to 15thDay
18%5%25%5%24445%40%
1980
16th to endDay
10%6%26%43445%6%44%
2116
April1st to 15thDay
13%425%425%448%44%
2060
16th to endDay
12%6%36%5%34447%42%
1980
May1st to 15thDay
14%7%36%6%3446%6%35%
1971
16th to endDay
7%425%6%36%5%7%10%39%
2164
June1st to 15thDay
5%425%5%46%7%9%10%38%
2145
16th to endDay
5%3246%28%6%8%11%39%
2145
July1st to 15thDay
9%336%7%37%6%7%11%33%
2145
16th to endDay
8%426%7%46%7%8%10%33%
2284
August1st to 15thDay
6%2146%36%7%8%10%42%
2032
16th to endDay
9%426%6%45%6%7%10%35%
2100
September1st to 15thDay
10%5%245%37%5%6%8%39%
1980
16th to endDay
10%4145%25%45%7%47%
1823
October1st to 15thDay
7%5%14434446%53%
1650
16th to endDay
14%41321213458%
1760
November1st to 15thDay
10%424323345%55%
1758
16th to endDay
15%6%24324235%48%
1728
December1st to 15thDay
19%8%35%5%2433439%
1553
16th to endDay
18%7%36%424346%38%
1728
January1st to 15thNight
16%6%24323335%48%
2327
16th to endNight
19%5%24422335%45%
2496
February1st to 15thNight
14%7%34323435%47%
2193
16th to endNight
17%6%24323336%45%
1871
March1st to 15thNight
16%5%25%32435%7%44%
1980
16th to endNight
12%6%24423346%49%
2106
April1st to 15thNight
9%3243235%5%7%53%
1727
16th to endNight
9%5%24423446%51%
1650
May1st to 15thNight
10%425%5%25%47%8%44%
1649
16th to endNight
6%325%4245%5%10%50%
1595
June1st to 15thNight
4212425%47%11%52%
1485
16th to endNight
5%323425%5%7%9%51%
1485
July1st to 15thNight
7%3245%25%5%7%10%47%
1485
16th to endNight
5%2123246%9%11%49%
1576
August1st to 15thNight
3213325%5%7%13%52%
1597
16th to endNight
7%5%23425%5%8%11%43%
1750
September1st to 15thNight
8%4244245%6%8%47%
1650
16th to endNight
8%424423446%54%
1792
October1st to 15thNight
7%315%424336%57%
1980
16th to endNight
11%313212335%60%
2112
November1st to 15thNight
9%424323346%56%
2100
16th to endNight
14%5%2441223453%
2225
December1st to 15thNight
18%6%25%313236%46%
2397
16th to endNight
17%7%25%42334442%
2496

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
42%3419%22%7%
1612
16th to endDay
45%1317%23%8%
1728
February1st to 15thDay
43%25%19%20%7%
1659
16th to endDay
45%25%17%22%6%
1612
March1st to 15thDay
46%37%17%18%5%
1980
16th to endDay
40%410%19%22%2
2118
April1st to 15thDay
38%38%21%19%7%
2060
16th to endDay
41%38%20%21%4
1980
May1st to 15thDay
48%5%10%15%15%4
1971
16th to endDay
38%5%14%27%13%1
2168
June1st to 15thDay
35%7%14%26%15%
2145
16th to endDay
35%7%13%22%17%3
2145
July1st to 15thDay
38%7%17%24%9%1
2006
16th to endDay
40%7%18%21%10%
2129
August1st to 15thDay
31%8%17%25%14%1
2018
16th to endDay
39%7%15%19%13%3
2100
September1st to 15thDay
41%6%12%20%13%6%
1980
16th to endDay
34%48%19%22%9%
1823
October1st to 15thDay
31%47%18%23%16%
1650
16th to endDay
30%1316%32%14%
1760
November1st to 15thDay
31%26%20%30%8%
1758
16th to endDay
39%2416%27%9%
1728
December1st to 15thDay
49%27%17%15%7%
1553
16th to endDay
48%27%19%17%4
1728
January1st to 15thNight
39%26%15%27%8%
2327
16th to endNight
42%3418%22%9%
2496
February1st to 15thNight
40%25%19%22%8%
2202
16th to endNight
41%3419%20%10%
1871
March1st to 15thNight
40%39%17%20%7%
1980
16th to endNight
36%39%20%23%5%
2106
April1st to 15thNight
30%411%23%20%10%
1727
16th to endNight
34%37%21%25%7%
1650
May1st to 15thNight
36%5%11%21%18%6%
1650
16th to endNight
29%5%15%27%19%2
1597
June1st to 15thNight
24%5%16%32%18%1
1485
16th to endNight
27%7%15%25%20%4
1485
July1st to 15thNight
29%6%24%24%13%2
1395
16th to endNight
23%8%26%27%13%1
1468
August1st to 15thNight
21%7%23%26%17%4
1587
16th to endNight
32%7%18%20%16%4
1750
September1st to 15thNight
32%7%14%22%15%8%
1650
16th to endNight
30%47%17%26%12%
1792
October1st to 15thNight
29%27%16%25%17%
1980
16th to endNight
28%2415%30%19%
2112
November1st to 15thNight
28%39%19%27%12%
2100
16th to endNight
35%15%14%28%14%
2225
December1st to 15thNight
42%28%20%19%6%
2397
16th to endNight
45%26%18%20%5%
2496

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%10%38%20%10%1
90
16th to endDay
22%16%41%13%5%
96
February1st to 15thDay
20%8%40%27%3
90
16th to endDay
14%14%39%25%31
81
March1st to 15thDay
22%16%42%17%1
90
16th to endDay
6%18%26%34%12%
102
April1st to 15thDay
16%11%28%30%12%
240
16th to endDay
20%5%17%34%20%2
210
May1st to 15thDay
18%127%33%16%3
228
16th to endDay
8%317%27%32%10%
379
June1st to 15thDay
7%16%32%39%13%
420
16th to endDay
5%15%25%41%20%
420
July1st to 15thDay
6%17%26%40%18%
400
16th to endDay
9%17%42%28%
445
August1st to 15thDay
6%115%42%32%
305
16th to endDay
11%1214%36%33%
268
September1st to 15thDay
10%7%16%40%25%
255
16th to endDay
10%10%16%43%18%
177
October1st to 15thDay
1125%28%35%7%
90
16th to endDay
17%121%20%25%13%
96
November1st to 15thDay
21%235%26%11%3
90
16th to endDay
22%435%18%14%4
90
December1st to 15thDay
24%7%36%14%15%1
90
16th to endDay
15%16%36%20%7%3
96
January1st to 15thNight
19%7%31%32%9%
900
16th to endNight
23%6%34%30%5%
960
February1st to 15thNight
18%9%32%32%6%
794
16th to endNight
19%10%37%29%2
609
March1st to 15thNight
17%6%32%36%6%
540
16th to endNight
14%5%30%34%13%
576
April1st to 15thNight
9%9%35%31%12%
518
16th to endNight
13%5%28%36%14%1
495
May1st to 15thNight
11%126%44%14%1
495
16th to endNight
8%215%35%33%4
515
June1st to 15thNight
5%6%40%40%6%
495
16th to endNight
5%17%25%49%11%
495
July1st to 15thNight
6%15%28%47%10%
465
16th to endNight
5%122%54%14%
522
August1st to 15thNight
4319%50%22%
494
16th to endNight
9%326%47%12%
525
September1st to 15thNight
10%15%34%38%9%
495
16th to endNight
10%17%33%43%4
561
October1st to 15thNight
9%218%30%35%4
660
16th to endNight
13%319%33%25%4
704
November1st to 15thNight
11%323%35%23%2
700
16th to endNight
16%5%28%31%16%1
720
December1st to 15thNight
21%6%26%33%10%
819
16th to endNight
23%9%26%30%9%
960
Page generated at 2017-04-09 05:54:17. Version ac04

Copyright 2017 A. Danko


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