Black Bayou Lake NWR
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Black Bayou Lake NWR clear sky chart from 2005-11-06 to 2024-01-13.

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
51%
23876
24%
74460
18%
23818
57%
23818
31%
44272

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 10thNight
33%
950
25%
2458
10%
946
42%
946
31%
1575
January11th to 20thNight
30%
915
25%
2379
9%
915
39%
915
28%
1594
January21st to endNight
29%
990
26%
2574
9%
990
39%
990
28%
1718
February1st to 10thNight
31%
863
23%
2303
8%
863
41%
863
28%
1528
February11th to 20thNight
28%
703
20%
2099
9%
700
36%
700
24%
1379
February21st to endNight
23%
555
23%
1739
8%
555
36%
555
20%
1177
March1st to 10thNight
36%
540
25%
1980
17%
540
46%
540
24%
1180
March11th to 20thNight
34%
540
20%
1980
13%
540
43%
540
21%
1241
March21st to endNight
37%
594
23%
2171
16%
594
49%
594
25%
1279
April1st to 10thNight
39%
540
26%
1800
16%
540
52%
540
31%
1018
April11th to 20thNight
38%
533
25%
1775
17%
533
50%
533
28%
1048
April21st to endNight
44%
540
28%
1800
23%
540
56%
540
31%
1020
May1st to 10thNight
53%
540
22%
1800
19%
540
61%
540
31%
1024
May11th to 20thNight
54%
531
22%
1769
23%
531
58%
531
32%
1018
May21st to endNight
62%
584
23%
1745
22%
582
66%
582
36%
1001
June1st to 10thNight
72%
540
18%
1620
20%
540
74%
540
35%
961
June11th to 20thNight
77%
540
21%
1620
22%
540
79%
540
43%
855
June21st to endNight
75%
540
22%
1620
24%
540
76%
540
38%
942
July1st to 10thNight
79%
525
17%
1575
20%
525
80%
525
35%
934
July11th to 20thNight
80%
522
19%
1566
21%
522
81%
522
38%
881
July21st to endNight
83%
591
22%
1673
25%
558
84%
558
41%
924
August1st to 10thNight
86%
537
20%
1685
24%
534
87%
534
44%
873
August11th to 20thNight
79%
534
22%
1776
27%
534
79%
534
35%
998
August21st to endNight
75%
594
21%
1980
26%
594
76%
594
31%
1151
September1st to 10thNight
75%
540
24%
1800
27%
540
76%
540
32%
1037
September11th to 20thNight
68%
540
26%
1800
28%
540
69%
540
30%
1079
September21st to endNight
72%
648
32%
2034
31%
648
73%
648
40%
1090
October1st to 10thNight
67%
720
30%
2160
25%
720
70%
720
43%
1143
October11th to 20thNight
55%
720
34%
2160
24%
720
63%
720
37%
1204
October21st to endNight
51%
792
32%
2376
24%
792
60%
792
37%
1353
November1st to 10thNight
56%
740
31%
2220
24%
740
63%
740
40%
1232
November11th to 20thNight
47%
760
30%
2280
23%
760
55%
760
36%
1296
November21st to endNight
42%
760
28%
2375
19%
760
51%
760
29%
1444
December1st to 10thNight
39%
828
25%
2538
16%
828
48%
828
26%
1596
December11th to 20thNight
35%
949
24%
2905
10%
948
42%
948
24%
1875
December21st to endNight
32%
1038
15%
4325
10%
1026
40%
1026
18%
2604

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%6%25%5%35%5%5%8%44%
74713
Night
12%5%2443445%7%49%
75029
TransparencyDay
38%7%11%19%19%5%
74438
Night
34%6%11%20%21%8%
74825
SeeingDay
13%7%20%25%24%10%
13993
Night
14%6%23%32%21%3
23884

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 10thDay
19%8%35%42335%5%45%
1707
11th to 20thDay
21%8%35%43333442%
1638
21st to endDay
19%8%35%42333447%
1782
February1st to 10thDay
20%8%35%423445%40%
1656
11th to 20thDay
23%7%36%43343440%
1748
21st to endDay
22%9%45%5%33335%37%
1532
March1st to 10thDay
18%7%26%6%3445%6%39%
1980
11th to 20thDay
15%7%36%5%35%45%7%39%
1980
21st to endDay
12%7%36%6%345%5%6%45%
2182
April1st to 10thDay
13%5%35%5%35%5%6%8%43%
2160
11th to 20thDay
16%6%35%5%3435%7%42%
2134
21st to endDay
10%6%36%6%45%5%48%45%
2160
May1st to 10thDay
13%6%37%5%36%45%6%42%
2160
11th to 20thDay
11%5%36%5%346%7%9%41%
2124
21st to endDay
8%425%5%46%6%7%9%43%
2528
June1st to 10thDay
8%435%6%47%7%9%10%39%
2340
11th to 20thDay
5%325%5%47%6%7%9%45%
2340
21st to endDay
5%426%5%46%7%8%11%41%
2340
July1st to 10thDay
7%426%8%5%7%7%7%11%35%
2340
11th to 20thDay
7%5%25%7%5%5%7%7%11%39%
2340
21st to endDay
7%425%6%5%7%7%8%11%37%
2546
August1st to 10thDay
5%325%5%5%6%7%8%12%43%
2240
11th to 20thDay
8%426%6%45%7%7%10%42%
2125
21st to endDay
11%425%5%46%6%7%10%41%
2376
September1st to 10thDay
7%425%7%46%6%6%9%45%
2160
11th to 20thDay
13%5%25%5%35%5%5%8%43%
2160
21st to endDay
10%4244335%5%6%55%
1902
October1st to 10thDay
6%3245%2445%6%59%
1800
11th to 20thDay
11%5%24423347%55%
1800
21st to endDay
15%5%25%323345%53%
1980
November1st to 10thDay
12%5%23423435%56%
1858
11th to 20thDay
12%5%25%434435%54%
1900
21st to endDay
17%6%25%434446%44%
1795
December1st to 10thDay
17%8%35%5%34445%43%
1638
11th to 20thDay
16%9%35%5%34445%42%
2127
21st to endDay
16%7%25%6%3445%6%42%
3135
January1st to 10thNight
18%5%25%32335%5%49%
2458
11th to 20thNight
20%6%35%423336%45%
2379
21st to endNight
19%7%25%42434446%
2574
February1st to 10thNight
16%7%35%424446%44%
2303
11th to 20thNight
20%7%35%434435%43%
2098
21st to endNight
22%7%35%5%24445%40%
1739
March1st to 10thNight
15%6%36%43445%6%45%
1980
11th to 20thNight
15%6%345%35%5%5%8%41%
1980
21st to endNight
13%6%35%434446%47%
2171
April1st to 10thNight
11%5%244345%6%7%50%
1800
11th to 20thNight
15%6%2442436%6%48%
1775
21st to endNight
10%5%35%5%3435%7%52%
1800
May1st to 10thNight
9%5%25%42435%10%50%
1800
11th to 20thNight
10%425%5%3446%10%46%
1769
21st to endNight
7%425%6%345%6%10%49%
1745
June1st to 10thNight
7%325%4445%8%11%47%
1620
11th to 20thNight
4323325%5%7%11%56%
1620
21st to endNight
6%224435%5%8%8%52%
1620
July1st to 10thNight
5%4245%45%5%8%11%46%
1620
11th to 20thNight
6%323426%5%9%11%49%
1620
21st to endNight
4213335%5%9%14%50%
1772
August1st to 10thNight
2213435%6%8%12%54%
1695
11th to 20thNight
6%5%14435%5%8%13%47%
1776
21st to endNight
9%3244246%8%9%48%
1980
September1st to 10thNight
6%425%5%35%6%6%7%51%
1800
11th to 20thNight
10%5%25%5%345%6%6%49%
1800
21st to endNight
9%41342335%6%59%
2034
October1st to 10thNight
7%3145%2435%7%60%
2160
11th to 20thNight
10%5%24433446%57%
2160
21st to endNight
13%423433345%57%
2376
November1st to 10thNight
12%324323436%57%
2220
11th to 20thNight
13%424423336%56%
2280
21st to endNight
15%6%25%5%24445%48%
2375
December1st to 10thNight
17%7%35%32345%6%45%
2538
11th to 20thNight
15%8%35%5%3343447%
3060
21st to endNight
17%8%35%5%23345%45%
4532

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 10thDay
42%46%21%21%7%
1708
11th to 20thDay
47%35%16%22%7%
1638
21st to endDay
43%2417%27%7%
1782
February1st to 10thDay
46%46%16%17%10%
1656
11th to 20thDay
48%45%17%19%7%
1758
21st to endDay
52%46%11%20%8%
1532
March1st to 10thDay
46%5%9%14%18%9%
1980
11th to 20thDay
45%6%9%16%17%6%
1980
21st to endDay
40%5%10%18%23%3
2182
April1st to 10thDay
39%6%9%22%17%7%
2160
11th to 20thDay
42%6%10%16%19%8%
2134
21st to endDay
38%5%9%22%23%3
2160
May1st to 10thDay
43%6%10%19%18%5%
2160
11th to 20thDay
38%8%14%24%15%1
2128
21st to endDay
34%8%16%26%15%1
2528
June1st to 10thDay
35%11%16%23%15%1
2340
11th to 20thDay
31%9%16%25%17%2
2340
21st to endDay
32%10%16%23%16%3
2340
July1st to 10thDay
37%11%22%21%8%1
2276
11th to 20thDay
34%11%21%23%10%1
2271
21st to endDay
35%12%20%21%10%1
2405
August1st to 10thDay
31%11%20%26%12%
2226
11th to 20thDay
35%11%16%22%14%2
2125
21st to endDay
36%9%19%20%13%3
2376
September1st to 10thDay
34%9%12%20%18%6%
2160
11th to 20thDay
38%8%11%17%20%6%
2160
21st to endDay
30%5%10%21%23%11%
1902
October1st to 10thDay
27%6%9%21%24%14%
1800
11th to 20thDay
30%46%19%27%14%
1800
21st to endDay
35%35%17%29%12%
1980
November1st to 10thDay
31%48%17%29%10%
1858
11th to 20thDay
33%46%18%27%12%
1900
21st to endDay
42%47%17%23%7%
1795
December1st to 10thDay
44%5%9%19%15%8%
1638
11th to 20thDay
46%45%14%26%5%
2125
21st to endDay
42%46%16%27%4
3135
January1st to 10thNight
38%47%17%27%7%
2458
11th to 20thNight
43%37%18%21%8%
2379
21st to endNight
42%4416%25%9%
2574
February1st to 10thNight
42%46%18%21%9%
2303
11th to 20thNight
45%45%18%20%8%
2099
21st to endNight
47%5%6%12%16%14%
1739
March1st to 10thNight
40%48%16%21%10%
1980
11th to 20thNight
42%7%11%15%18%8%
1980
21st to endNight
38%6%8%19%24%6%
2171
April1st to 10thNight
32%5%12%21%20%10%
1800
11th to 20thNight
36%5%9%18%20%11%
1775
21st to endNight
33%5%7%23%28%5%
1800
May1st to 10thNight
32%7%11%23%20%8%
1800
11th to 20thNight
32%7%13%28%19%2
1770
21st to endNight
29%7%16%27%20%1
1746
June1st to 10thNight
29%9%18%26%17%1
1620
11th to 20thNight
22%8%18%30%19%3
1620
21st to endNight
27%9%16%24%20%4
1620
July1st to 10thNight
27%11%25%25%10%2
1575
11th to 20thNight
23%12%24%25%14%2
1566
21st to endNight
21%11%25%28%13%2
1673
August1st to 10thNight
19%9%27%30%13%1
1685
11th to 20thNight
26%10%21%22%16%4
1776
21st to endNight
30%10%18%22%17%4
1980
September1st to 10thNight
30%9%13%24%16%9%
1800
11th to 20thNight
34%8%11%16%21%10%
1800
21st to endNight
27%49%22%24%13%
2034
October1st to 10thNight
25%410%20%24%16%
2160
11th to 20thNight
31%45%16%29%16%
2160
21st to endNight
31%46%17%27%15%
2376
November1st to 10thNight
29%39%18%26%14%
2220
11th to 20thNight
31%48%16%28%13%
2280
21st to endNight
39%36%17%25%10%
2375
December1st to 10thNight
40%5%9%20%19%7%
2538
11th to 20thNight
42%36%13%26%10%
3061
21st to endNight
42%46%19%24%6%
4532

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 10thDay
24%15%39%18%31
270
11th to 20thDay
25%16%34%17%6%1
246
21st to endDay
26%20%31%21%3
264
February1st to 10thDay
25%13%39%17%5%1
240
11th to 20thDay
35%15%34%13%2
240
21st to endDay
31%25%28%12%31
198
March1st to 10thDay
25%15%35%20%5%
240
11th to 20thDay
19%22%37%20%2
240
21st to endDay
18%21%35%18%8%
268
April1st to 10thDay
17%13%36%23%10%
420
11th to 20thDay
23%13%26%24%13%2
412
21st to endDay
16%14%26%28%15%1
420
May1st to 10thDay
15%8%32%28%15%2
423
11th to 20thDay
13%423%30%21%8%
447
21st to endDay
8%420%32%27%9%
676
June1st to 10thDay
10%312%30%31%15%
630
11th to 20thDay
5%212%34%37%9%
630
21st to endDay
8%112%27%34%17%
630
July1st to 10thDay
5%19%26%41%19%
621
11th to 20thDay
6%25%24%39%24%
618
21st to endDay
6%16%25%43%20%
684
August1st to 10thDay
426%20%46%22%
538
11th to 20thDay
10%2321%43%22%
439
21st to endDay
13%15%17%35%29%
495
September1st to 10thDay
6%16%25%42%19%
450
11th to 20thDay
11%111%20%37%20%
450
21st to endDay
11%312%27%33%14%
320
October1st to 10thDay
7%218%36%27%10%
270
11th to 20thDay
7%6%31%30%20%6%
270
21st to endDay
20%9%29%24%15%4
297
November1st to 10thDay
17%8%26%28%17%4
270
11th to 20thDay
13%11%35%27%12%2
270
21st to endDay
18%15%30%25%10%2
270
December1st to 10thDay
20%12%37%21%9%1
270
11th to 20thDay
23%13%34%22%7%1
270
21st to endDay
20%16%37%20%5%2
297
January1st to 10thNight
22%10%32%31%6%
950
11th to 20thNight
23%11%32%26%9%
915
21st to endNight
22%10%35%30%4
990
February1st to 10thNight
20%11%35%29%5%
863
11th to 20thNight
23%11%35%27%4
703
21st to endNight
25%13%34%25%3
555
March1st to 10thNight
18%8%34%33%7%
540
11th to 20thNight
17%9%36%30%6%1
540
21st to endNight
14%10%35%30%10%
594
April1st to 10thNight
12%9%38%32%9%
540
11th to 20thNight
17%9%32%29%11%1
533
21st to endNight
12%6%32%35%13%1
540
May1st to 10thNight
10%5%28%44%13%1
540
11th to 20thNight
11%227%35%22%2
531
21st to endNight
7%317%37%31%5%
584
June1st to 10thNight
8%29%38%37%6%
540
11th to 20thNight
4111%36%44%4
540
21st to endNight
7%19%31%42%10%
540
July1st to 10thNight
416%29%47%12%
525
11th to 20thNight
5%16%26%52%10%
522
21st to endNight
5%1331%48%12%
591
August1st to 10thNight
25%27%50%16%
537
11th to 20thNight
8%1430%48%9%
534
21st to endNight
10%17%24%45%13%
594
September1st to 10thNight
6%17%36%41%9%
540
11th to 20thNight
11%28%34%39%7%
540
21st to endNight
10%210%36%38%4
648
October1st to 10thNight
8%116%36%34%5%
720
11th to 20thNight
12%423%36%22%3
720
21st to endNight
14%6%25%33%19%4
792
November1st to 10thNight
13%323%37%21%3
740
11th to 20thNight
14%6%28%36%16%
760
21st to endNight
16%8%31%31%14%1
760
December1st to 10thNight
21%7%29%34%9%
828
11th to 20thNight
22%10%29%30%9%
950
21st to endNight
23%11%28%30%7%
1045
Page generated at 2024-01-10 09:16:13. Version ac07

Copyright 2024 Attilla Danko


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