Shreveport Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shreveport Observatory clear sky chart from 2005-11-05 to

2017-09-12
.

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
54%
15492
25%
46806
19%
15448
60%
15448
33%
27812

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
37%
899
25%
2327
12%
895
45%
895
30%
1530
January16th to endNight
33%
960
26%
2496
10%
960
42%
960
29%
1661
February1st to 15thNight
38%
873
24%
2282
10%
870
46%
870
33%
1448
February16th to endNight
30%
511
26%
1773
12%
511
44%
511
24%
1067
March1st to 15thNight
38%
540
24%
1980
17%
540
48%
540
23%
1195
March16th to endNight
44%
576
21%
2112
17%
576
52%
576
25%
1239
April1st to 15thNight
42%
539
25%
1852
19%
539
53%
539
32%
1028
April16th to endNight
42%
540
25%
1800
19%
540
54%
540
31%
1023
May1st to 15thNight
46%
540
19%
1761
16%
540
55%
540
26%
1080
May16th to endNight
63%
562
24%
1685
24%
561
67%
561
36%
982
June1st to 15thNight
82%
540
21%
1620
23%
540
84%
540
43%
878
June16th to endNight
76%
540
21%
1620
23%
540
78%
540
38%
921
July1st to 15thNight
82%
510
19%
1530
24%
510
83%
510
38%
882
July16th to endNight
82%
564
21%
1594
25%
531
83%
531
42%
894
August1st to 15thNight
88%
539
26%
1652
31%
536
88%
536
48%
833
August16th to endNight
73%
573
20%
1910
26%
573
73%
573
28%
1201
September1st to 15thNight
75%
530
22%
1789
26%
530
75%
530
33%
1020
September16th to endNight
75%
506
29%
1829
31%
506
76%
506
35%
956
October1st to 15thNight
70%
660
30%
1980
25%
660
72%
660
39%
1103
October16th to endNight
61%
704
36%
2112
27%
704
67%
704
42%
1117
November1st to 15thNight
56%
700
30%
2100
23%
700
61%
700
38%
1193
November16th to endNight
47%
726
32%
2166
22%
726
55%
726
33%
1307
December1st to 15thNight
43%
900
25%
2340
15%
900
49%
900
30%
1555
December16th to endNight
36%
960
22%
2496
11%
960
43%
960
28%
1699

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%3445%7%42%
47844
Night
11%424423447%50%
47001
TransparencyDay
39%6%10%18%18%5%
47544
Night
33%5%11%19%21%8%
46806
SeeingDay
11%314%24%31%14%
5543
Night
13%421%33%23%3
15494

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
18%7%2442322446%
1611
16th to endDay
18%6%2432344346%
1728
February1st to 15thDay
18%7%2443333443%
1580
16th to endDay
19%7%25%423335%42%
1709
March1st to 15thDay
21%6%35%423345%39%
1980
16th to endDay
14%6%35%42435%5%42%
2110
April1st to 15thDay
12%5%245%34346%47%
2094
16th to endDay
12%5%25%5%35%6%5%6%42%
2160
May1st to 15thDay
12%7%36%5%45%5%5%6%37%
2187
16th to endDay
8%4246%46%6%7%9%39%
2430
June1st to 15thDay
6%425%6%47%5%7%9%40%
2340
16th to endDay
6%425%7%47%7%8%8%38%
2340
July1st to 15thDay
8%335%6%5%6%6%7%10%35%
2340
16th to endDay
8%426%5%47%8%7%9%35%
2466
August1st to 15thDay
5%3145%36%6%7%9%46%
2295
16th to endDay
12%5%25%7%46%7%7%10%31%
2292
September1st to 15thDay
10%4345%45%5%5%6%43%
2087
16th to endDay
9%4145%3345%8%49%
1788
October1st to 15thDay
9%425%423446%53%
1650
16th to endDay
13%41331223459%
1760
November1st to 15thDay
11%425%32425%6%51%
1758
16th to endDay
17%6%24423235%48%
1791
December1st to 15thDay
18%9%25%312235%42%
1620
16th to endDay
17%9%36%424345%38%
1728
January1st to 15thNight
16%7%2442333448%
2327
16th to endNight
19%5%2432332348%
2496
February1st to 15thNight
15%6%2332333451%
2272
16th to endNight
17%5%2342323448%
1773
March1st to 15thNight
18%423424445%45%
1980
16th to endNight
11%5%244245%46%48%
2112
April1st to 15thNight
7%425%42445%8%51%
1852
16th to endNight
10%4245%23348%49%
1800
May1st to 15thNight
10%5%345%245%6%8%44%
1760
16th to endNight
7%42443445%10%49%
1683
June1st to 15thNight
321233446%11%55%
1620
16th to endNight
5%2135%3446%9%52%
1620
July1st to 15thNight
4323335%5%6%12%48%
1620
16th to endNight
32133245%7%13%50%
1702
August1st to 15thNight
22122145%6%12%57%
1662
16th to endNight
8%424435%5%7%10%41%
1910
September1st to 15thNight
8%415%43346%8%50%
1789
16th to endNight
7%31342335%8%55%
1829
October1st to 15thNight
6%3145%33446%56%
1980
16th to endNight
12%21321233463%
2112
November1st to 15thNight
9%5%24423336%56%
2100
16th to endNight
15%42442323452%
2166
December1st to 15thNight
16%6%24322436%46%
2340
16th to endNight
16%7%35%42334443%
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
43%3416%23%8%
1612
16th to endDay
42%35%17%22%8%
1728
February1st to 15thDay
45%36%16%18%9%
1581
16th to endDay
45%37%13%22%7%
1709
March1st to 15thDay
48%46%17%17%6%
1980
16th to endDay
44%48%16%23%2
2112
April1st to 15thDay
38%48%21%18%7%
2094
16th to endDay
40%7%9%17%20%4
2160
May1st to 15thDay
45%7%9%14%16%6%
2187
16th to endDay
37%8%15%24%12%1
2434
June1st to 15thDay
36%9%14%22%16%1
2340
16th to endDay
38%11%14%20%13%2
2340
July1st to 15thDay
38%9%18%23%9%
2201
16th to endDay
39%10%17%21%10%
2311
August1st to 15thDay
29%11%17%25%15%
2281
16th to endDay
44%11%16%15%10%1
2292
September1st to 15thDay
39%8%12%18%14%6%
2087
16th to endDay
32%6%10%20%20%8%
1788
October1st to 15thDay
30%5%8%17%21%15%
1650
16th to endDay
29%26%15%32%12%
1760
November1st to 15thDay
34%49%19%24%8%
1758
16th to endDay
40%3413%29%9%
1791
December1st to 15thDay
45%38%16%19%6%
1620
16th to endDay
47%47%17%18%3
1728
January1st to 15thNight
40%45%13%26%10%
2327
16th to endNight
42%35%14%22%11%
2496
February1st to 15thNight
36%46%18%23%10%
2282
16th to endNight
40%37%18%19%11%
1773
March1st to 15thNight
41%49%16%20%8%
1980
16th to endNight
35%7%9%18%23%5%
2112
April1st to 15thNight
30%5%10%23%19%10%
1852
16th to endNight
33%411%21%21%7%
1800
May1st to 15thNight
37%6%11%16%16%11%
1761
16th to endNight
29%6%16%24%20%1
1685
June1st to 15thNight
21%9%15%30%21%2
1620
16th to endNight
28%6%17%21%22%3
1620
July1st to 15thNight
25%9%23%27%11%1
1530
16th to endNight
22%9%26%25%14%1
1594
August1st to 15thNight
17%8%22%31%17%2
1652
16th to endNight
33%11%18%21%12%2
1910
September1st to 15thNight
30%7%16%19%16%9%
1789
16th to endNight
27%5%11%18%24%12%
1829
October1st to 15thNight
27%5%9%16%23%17%
1980
16th to endNight
26%25%15%30%19%
2112
November1st to 15thNight
30%38%19%26%10%
2100
16th to endNight
36%25%12%26%15%
2166
December1st to 15thNight
40%49%19%18%7%
2340
16th to endNight
43%47%17%21%6%
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
13%10%40%24%12%
90
16th to endDay
15%15%45%19%3
96
February1st to 15thDay
14%14%37%28%4
90
16th to endDay
19%12%35%28%3
81
March1st to 15thDay
24%16%37%15%5%
90
16th to endDay
9%14%27%31%16%1
96
April1st to 15thDay
13%8%33%26%15%1
213
16th to endDay
19%6%21%30%18%4
270
May1st to 15thDay
16%426%32%16%3
324
16th to endDay
9%422%30%28%5%
517
June1st to 15thDay
7%7%31%40%12%
495
16th to endDay
7%18%28%35%18%
495
July1st to 15thDay
6%6%23%41%20%
475
16th to endDay
6%314%44%30%
515
August1st to 15thDay
7%212%46%30%
448
16th to endDay
17%1213%39%25%
332
September1st to 15thDay
6%416%42%29%
274
16th to endDay
2224%42%28%
90
October1st to 15thDay
216%33%36%11%
90
16th to endDay
18%117%18%28%15%
96
November1st to 15thDay
15%224%36%20%1
90
16th to endDay
18%7%35%24%10%3
90
December1st to 15thDay
26%8%16%31%13%3
90
16th to endDay
18%16%35%22%5%1
96
January1st to 15thNight
19%7%30%31%10%
900
16th to endNight
22%6%34%32%4
960
February1st to 15thNight
18%7%31%35%6%
873
16th to endNight
20%8%38%29%3
511
March1st to 15thNight
18%7%29%37%6%
540
16th to endNight
14%432%38%9%
576
April1st to 15thNight
10%7%36%33%11%
539
16th to endNight
13%5%35%32%13%
540
May1st to 15thNight
12%432%35%13%1
540
16th to endNight
8%216%45%23%3
563
June1st to 15thNight
47%42%40%4
540
16th to endNight
46%34%44%9%
540
July1st to 15thNight
4234%51%5%
510
16th to endNight
41323%55%12%
564
August1st to 15thNight
3116%64%12%
539
16th to endNight
10%424%48%12%
573
September1st to 15thNight
10%1328%46%9%
530
16th to endNight
9%7%32%43%6%
506
October1st to 15thNight
8%212%38%34%4
660
16th to endNight
13%317%35%25%4
704
November1st to 15thNight
11%323%37%21%2
700
16th to endNight
17%5%26%33%15%1
726
December1st to 15thNight
20%6%25%36%10%
900
16th to endNight
19%8%31%32%8%
960
Page generated at 2017-09-13 06:39:11. Version ac04

Copyright 2017 A. Danko


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