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 2018-03-21.

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%
15911
24%
49125
18%
15868
58%
15868
30%
29793

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%
780
25%
2476
12%
776
45%
776
24%
1526
January16th to endNight
30%
832
26%
2496
14%
832
41%
832
24%
1643
February1st to 15thNight
31%
764
25%
2292
11%
761
42%
761
26%
1449
February16th to endNight
30%
683
25%
2049
12%
683
41%
683
27%
1293
March1st to 15thNight
32%
780
21%
2340
11%
780
40%
780
27%
1475
March16th to endNight
41%
678
25%
2089
15%
678
50%
678
30%
1253
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
64%
591
21%
1851
21%
591
66%
591
27%
1166
September16th to endNight
67%
717
29%
1980
24%
717
70%
717
39%
1150
October1st to 15thNight
62%
720
33%
1980
27%
720
67%
720
43%
1123
October16th to endNight
55%
768
35%
2319
29%
768
62%
768
38%
1287
November1st to 15thNight
54%
760
30%
2471
26%
760
63%
760
36%
1333
November16th to endNight
44%
780
30%
2535
22%
780
57%
780
33%
1413
December1st to 15thNight
39%
780
23%
2535
17%
780
48%
780
25%
1588
December16th to endNight
31%
832
20%
2704
13%
832
40%
832
19%
1850

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%
49677
Night
12%42442445%7%47%
49332
TransparencyDay
39%6%11%19%18%5%
49387
Night
35%5%10%19%20%7%
49126
SeeingDay
13%6%18%23%23%14%
5777
Night
13%6%22%29%23%5%
15913

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%34324335%43%
1791
16th to endDay
18%5%23322345%48%
2080
February1st to 15thDay
17%7%25%424345%42%
1900
16th to endDay
20%5%24333336%41%
1710
March1st to 15thDay
16%5%45%423345%43%
1950
16th to endDay
13%5%25%5%3445%7%43%
2270
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
10%5%26%5%345%7%9%39%
2097
16th to endDay
10%425%43446%6%47%
1980
October1st to 15thDay
9%4145%23446%53%
1980
16th to endDay
11%314323235%58%
1900
November1st to 15thDay
11%423323335%55%
1717
16th to endDay
14%414313346%52%
1755
December1st to 15thDay
18%8%23313346%42%
1755
16th to endDay
24%9%35%5%23225%34%
1872
January1st to 15thNight
16%5%2442334448%
2476
16th to endNight
17%6%25%424435%43%
2496
February1st to 15thNight
17%6%24313346%45%
2283
16th to endNight
18%425%323346%45%
2049
March1st to 15thNight
16%5%2442435%5%45%
2340
16th to endNight
12%6%2442335%6%49%
2089
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%5%5%8%43%
1851
16th to endNight
8%4244225%46%54%
1980
October1st to 15thNight
9%413313446%57%
1980
16th to endNight
12%42331222459%
2319
November1st to 15thNight
10%423313347%55%
2471
16th to endNight
11%423413345%55%
2535
December1st to 15thNight
17%6%24423336%45%
2535
16th to endNight
21%6%35%423446%36%
2704

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%35%16%24%5%
1792
16th to endDay
39%36%20%22%7%
2080
February1st to 15thDay
45%36%22%17%4
1902
16th to endDay
45%47%15%21%5%
1710
March1st to 15thDay
43%48%16%20%7%
1950
16th to endDay
40%6%9%20%20%2
2271
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
40%9%13%16%14%5%
2097
16th to endDay
36%6%11%19%20%6%
1980
October1st to 15thDay
32%49%18%23%11%
1980
16th to endDay
29%3416%35%10%
1900
November1st to 15thDay
32%36%18%29%9%
1717
16th to endDay
33%36%18%27%10%
1755
December1st to 15thDay
43%5%8%19%16%6%
1755
16th to endDay
54%27%18%13%3
1872
January1st to 15thNight
39%35%19%25%5%
2476
16th to endNight
43%4417%21%8%
2496
February1st to 15thNight
41%35%19%20%8%
2292
16th to endNight
40%36%19%22%7%
2049
March1st to 15thNight
39%48%16%21%9%
2340
16th to endNight
35%49%23%22%4
2089
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%
1851
16th to endNight
29%5%11%24%21%8%
1980
October1st to 15thNight
27%48%20%24%14%
1980
16th to endNight
30%2411%32%18%
2319
November1st to 15thNight
28%48%16%27%14%
2471
16th to endNight
31%46%18%25%13%
2535
December1st to 15thNight
41%49%18%21%5%
2535
16th to endNight
49%5%7%16%16%5%
2704

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%18%35%23%5%1
135
16th to endDay
22%22%34%14%42
144
February1st to 15thDay
28%18%33%17%2
135
16th to endDay
29%10%40%20%
120
March1st to 15thDay
21%22%37%14%2
135
16th to endDay
20%9%30%23%15%1
285
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
12%28%22%33%20%
315
16th to endDay
8%19%29%40%10%
314
October1st to 15thDay
11%317%30%31%5%
315
16th to endDay
13%9%25%25%21%4
174
November1st to 15thDay
19%235%29%10%2
135
16th to endDay
11%11%31%27%15%2
135
December1st to 15thDay
25%14%28%25%5%2
135
16th to endDay
36%13%25%18%5%
144
January1st to 15thNight
20%13%31%26%8%
780
16th to endNight
19%12%33%28%5%
832
February1st to 15thNight
21%9%32%29%5%
764
16th to endNight
20%10%34%30%3
683
March1st to 15thNight
18%10%34%28%8%
780
16th to endNight
14%10%30%27%16%
678
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%10%26%36%12%
591
16th to endNight
10%111%35%36%5%
717
October1st to 15thNight
10%219%31%31%4
720
16th to endNight
14%6%17%31%26%2
768
November1st to 15thNight
12%5%22%33%21%4
760
16th to endNight
13%8%29%31%15%2
780
December1st to 15thNight
20%7%28%30%13%
780
16th to endNight
23%10%30%27%8%
832
Page generated at 2018-03-22 10:34:24. Version ac04

Copyright 2018 A. Danko


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