Tuscaloosa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tuscaloosa 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
51%
15150
24%
46806
18%
15107
58%
15107
30%
28386

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
31%
720
26%
2285
12%
716
46%
716
24%
1409
January16th to endNight
29%
768
25%
2304
13%
768
40%
768
23%
1543
February1st to 15thNight
32%
704
26%
2112
11%
701
45%
701
28%
1301
February16th to endNight
31%
631
26%
1893
12%
631
42%
631
28%
1177
March1st to 15thNight
32%
720
20%
2160
11%
720
39%
720
27%
1377
March16th to endNight
42%
654
25%
2021
15%
654
50%
654
30%
1205
April1st to 15thNight
43%
539
25%
1797
18%
539
53%
539
31%
1020
April16th to endNight
50%
540
27%
1800
21%
540
61%
540
33%
985
May1st to 15thNight
51%
540
21%
1692
15%
540
59%
540
30%
1033
May16th to endNight
69%
561
24%
1683
21%
561
72%
561
37%
993
June1st to 15thNight
73%
540
16%
1620
15%
540
73%
540
31%
992
June16th to endNight
79%
540
20%
1555
18%
540
79%
540
37%
913
July1st to 15thNight
76%
510
15%
1473
15%
510
76%
510
31%
948
July16th to endNight
75%
564
15%
1690
15%
531
78%
531
29%
1051
August1st to 15thNight
79%
539
17%
1788
20%
536
79%
536
29%
1075
August16th to endNight
70%
573
21%
1910
25%
573
70%
573
25%
1234
September1st to 15thNight
65%
578
21%
1815
22%
578
67%
578
28%
1135
September16th to endNight
65%
657
28%
1815
22%
657
68%
657
38%
1070
October1st to 15thNight
61%
660
34%
1815
27%
660
67%
660
42%
1036
October16th to endNight
55%
704
34%
2126
29%
704
62%
704
37%
1184
November1st to 15thNight
54%
700
30%
2276
26%
700
63%
700
37%
1213
November16th to endNight
42%
720
29%
2340
20%
720
55%
720
32%
1330
December1st to 15thNight
39%
720
23%
2340
18%
720
48%
720
25%
1469
December16th to endNight
31%
768
20%
2496
14%
768
40%
768
19%
1693

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%43%
47807
Night
12%42442445%7%47%
47013
TransparencyDay
39%6%11%19%18%5%
47517
Night
35%6%10%19%20%7%
46807
SeeingDay
13%5%17%24%24%15%
5165
Night
13%6%21%29%23%5%
15152

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%3431433443%
1652
16th to endDay
19%5%23322445%47%
1920
February1st to 15thDay
16%7%25%324345%44%
1750
16th to endDay
20%5%24322335%42%
1580
March1st to 15thDay
16%5%46%5%33346%41%
1800
16th to endDay
13%425%5%35%45%7%44%
2210
April1st to 15thDay
13%32432445%8%46%
2151
16th to endDay
9%4145%35%45%7%47%
2160
May1st to 15thDay
13%5%25%33445%7%44%
2256
16th to endDay
8%415%6%26%5%5%8%43%
2431
June1st to 15thDay
7%425%7%35%6%8%10%38%
2340
16th to endDay
5%314436%6%7%10%44%
2389
July1st to 15thDay
9%425%6%5%8%8%8%10%31%
2382
16th to endDay
7%326%7%48%7%7%11%34%
2359
August1st to 15thDay
8%4246%46%6%8%11%36%
2160
16th to endDay
12%5%25%6%46%6%7%10%32%
2292
September1st to 15thDay
9%5%26%5%35%5%7%9%39%
2053
16th to endDay
11%5%25%43446%6%46%
1815
October1st to 15thDay
9%3145%2345%6%52%
1815
16th to endDay
12%213323235%58%
1742
November1st to 15thDay
11%423323335%56%
1582
16th to endDay
15%414313346%51%
1620
December1st to 15thDay
18%8%2342345%6%41%
1620
16th to endDay
23%9%35%5%23225%35%
1728
January1st to 15thNight
16%5%2442334447%
2285
16th to endNight
18%6%35%42443441%
2304
February1st to 15thNight
15%5%24413346%47%
2103
16th to endNight
17%5%24323345%46%
1893
March1st to 15thNight
17%5%2432435%6%44%
2160
16th to endNight
12%6%2442335%6%49%
2021
April1st to 15thNight
11%42432345%7%49%
1797
16th to endNight
9%314424447%54%
1800
May1st to 15thNight
11%4145%24448%47%
1691
16th to endNight
6%3144345%6%9%49%
1682
June1st to 15thNight
5%3145%45%6%6%11%44%
1620
16th to endNight
33135%35%6%7%12%45%
1555
July1st to 15thNight
5%425%6%35%6%7%10%41%
1563
16th to endNight
5%3246%25%7%8%12%40%
1806
August1st to 15thNight
6%2245%46%6%9%11%41%
1800
16th to endNight
8%426%5%346%6%10%40%
1910
September1st to 15thNight
10%425%5%35%45%8%44%
1815
16th to endNight
8%5%24423447%53%
1815
October1st to 15thNight
9%414313446%57%
1815
16th to endNight
12%5%2331223459%
2126
November1st to 15thNight
10%423313347%56%
2276
16th to endNight
12%423413345%53%
2340
December1st to 15thNight
16%5%25%423336%45%
2340
16th to endNight
21%6%35%423346%37%
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
44%3415%25%5%
1653
16th to endDay
40%36%20%22%6%
1920
February1st to 15thDay
43%27%22%18%5%
1752
16th to endDay
44%37%15%23%6%
1580
March1st to 15thDay
45%48%17%18%6%
1800
16th to endDay
40%5%9%20%20%2
2211
April1st to 15thDay
36%5%9%20%19%7%
2151
16th to endDay
35%6%9%21%24%3
2160
May1st to 15thDay
39%6%10%17%20%5%
2256
16th to endDay
37%8%13%22%15%2
2435
June1st to 15thDay
37%9%17%21%12%1
2340
16th to endDay
31%10%15%21%16%4
2389
July1st to 15thDay
41%13%16%18%7%2
2243
16th to endDay
41%11%18%18%9%
2212
August1st to 15thDay
37%11%17%18%11%3
2148
16th to endDay
45%9%15%18%8%2
2292
September1st to 15thDay
39%9%13%16%14%5%
2053
16th to endDay
37%5%9%18%20%7%
1815
October1st to 15thDay
31%5%10%16%24%12%
1815
16th to endDay
30%3415%34%10%
1742
November1st to 15thDay
32%25%19%29%10%
1582
16th to endDay
34%37%18%26%9%
1620
December1st to 15thDay
43%5%8%20%15%6%
1620
16th to endDay
53%27%17%14%4
1728
January1st to 15thNight
39%45%18%26%5%
2285
16th to endNight
45%4416%21%7%
2304
February1st to 15thNight
38%36%20%21%9%
2112
16th to endNight
40%35%19%23%8%
1893
March1st to 15thNight
40%48%17%20%8%
2160
16th to endNight
34%49%23%22%4
2021
April1st to 15thNight
32%410%22%20%8%
1797
16th to endNight
29%6%9%22%25%6%
1800
May1st to 15thNight
35%6%10%17%22%7%
1692
16th to endNight
29%7%15%25%16%5%
1684
June1st to 15thNight
32%8%17%20%17%2
1620
16th to endNight
28%8%19%21%19%3
1555
July1st to 15thNight
34%9%21%21%10%2
1473
16th to endNight
30%13%24%20%10%
1690
August1st to 15thNight
30%11%18%21%13%3
1788
16th to endNight
37%10%15%19%13%3
1910
September1st to 15thNight
37%7%15%18%13%6%
1815
16th to endNight
31%5%10%22%21%9%
1815
October1st to 15thNight
27%48%18%25%15%
1815
16th to endNight
30%2411%31%18%
2126
November1st to 15thNight
28%46%16%28%15%
2276
16th to endNight
33%46%18%24%13%
2340
December1st to 15thNight
41%48%19%20%5%
2340
16th to endNight
48%47%15%17%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
15%15%37%22%6%2
90
16th to endDay
23%25%36%11%12
96
February1st to 15thDay
18%22%33%24%1
90
16th to endDay
28%11%35%24%
81
March1st to 15thDay
25%20%34%14%41
90
16th to endDay
19%7%29%25%17%1
264
April1st to 15thDay
16%11%25%24%19%2
270
16th to endDay
10%8%24%31%21%4
270
May1st to 15thDay
14%6%21%28%18%9%
288
16th to endDay
11%318%28%21%16%
331
June1st to 15thDay
9%111%24%27%26%
315
16th to endDay
8%9%25%30%25%
364
July1st to 15thDay
6%7%22%37%26%
347
16th to endDay
7%15%13%34%38%
326
August1st to 15thDay
12%419%35%27%
313
16th to endDay
13%16%23%30%24%
332
September1st to 15thDay
10%29%22%34%21%
299
16th to endDay
9%210%30%38%8%
254
October1st to 15thDay
10%318%30%31%5%
255
16th to endDay
17%419%27%25%5%
124
November1st to 15thDay
21%240%22%12%2
90
16th to endDay
13%13%33%26%11%2
90
December1st to 15thDay
24%16%30%20%6%2
90
16th to endDay
38%11%26%17%5%1
96
January1st to 15thNight
20%12%31%26%8%
720
16th to endNight
20%12%34%28%4
768
February1st to 15thNight
19%9%33%30%5%
704
16th to endNight
20%10%34%30%4
631
March1st to 15thNight
19%10%34%27%8%
720
16th to endNight
14%10%29%27%17%
654
April1st to 15thNight
10%10%32%28%16%
539
16th to endNight
10%7%28%35%16%2
540
May1st to 15thNight
12%226%32%22%3
540
16th to endNight
7%113%34%36%6%
563
June1st to 15thNight
7%8%35%40%8%
540
16th to endNight
416%25%46%15%
540
July1st to 15thNight
5%5%26%44%16%
510
16th to endNight
5%6%22%43%21%
564
August1st to 15thNight
7%322%49%16%
539
16th to endNight
10%16%24%40%16%
573
September1st to 15thNight
13%9%26%36%12%
578
16th to endNight
11%111%37%34%4
657
October1st to 15thNight
10%219%31%30%4
660
16th to endNight
14%7%17%32%25%2
704
November1st to 15thNight
12%5%22%33%21%4
700
16th to endNight
14%8%30%31%13%1
720
December1st to 15thNight
20%7%28%30%12%
720
16th to endNight
24%10%29%27%8%
768
Page generated at 2017-09-13 06:39:17. Version ac04

Copyright 2017 A. Danko


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