Mobile
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mobile clear sky chart from 2005-11-05 to 2018-01-20.

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
56%
15633
23%
48548
18%
15587
62%
15587
31%
28949

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%
780
25%
2354
12%
776
48%
776
28%
1438
January16th to endNight
33%
788
26%
2364
14%
788
43%
788
26%
1492
February1st to 15thNight
37%
704
28%
2108
13%
699
49%
699
31%
1252
February16th to endNight
32%
631
23%
1893
11%
631
42%
631
24%
1225
March1st to 15thNight
39%
720
22%
2160
13%
720
46%
720
27%
1379
March16th to endNight
50%
624
26%
2007
20%
624
57%
624
32%
1137
April1st to 15thNight
49%
539
24%
1797
20%
539
57%
539
30%
1041
April16th to endNight
62%
540
29%
1800
28%
540
69%
540
42%
909
May1st to 15thNight
63%
539
20%
1796
18%
539
69%
539
35%
990
May16th to endNight
72%
562
22%
1682
22%
561
74%
561
37%
976
June1st to 15thNight
76%
540
13%
1620
14%
540
76%
540
34%
975
June16th to endNight
77%
540
16%
1620
16%
540
77%
540
30%
1001
July1st to 15thNight
81%
510
11%
1591
12%
510
81%
510
30%
995
July16th to endNight
81%
564
11%
1772
15%
531
81%
531
26%
1113
August1st to 15thNight
84%
539
10%
1788
12%
536
85%
536
29%
1101
August16th to endNight
72%
573
15%
1910
18%
573
73%
573
22%
1257
September1st to 15thNight
70%
583
18%
1843
19%
583
72%
583
29%
1148
September16th to endNight
68%
717
26%
1980
22%
717
69%
717
34%
1219
October1st to 15thNight
67%
720
31%
1980
24%
720
72%
720
44%
1094
October16th to endNight
57%
768
36%
2262
29%
768
65%
768
43%
1206
November1st to 15thNight
58%
760
30%
2447
26%
760
67%
760
37%
1316
November16th to endNight
51%
780
32%
2535
25%
780
63%
780
36%
1354
December1st to 15thNight
42%
780
25%
2535
19%
780
51%
780
27%
1537
December16th to endNight
33%
832
20%
2704
13%
832
41%
832
21%
1794

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
9%4245%35%5%6%8%42%
48943
Night
9%42442445%8%47%
48770
TransparencyDay
37%8%13%18%16%6%
48662
Night
33%6%14%18%18%8%
48555
SeeingDay
11%414%23%26%18%
5495
Night
11%5%19%29%26%7%
15635

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
11%5%15%5%3345%7%45%
1911
16th to endDay
18%5%2442333446%
1964
February1st to 15thDay
13%413424347%47%
1750
16th to endDay
14%425%43435%5%45%
1580
March1st to 15thDay
13%5%24434447%45%
1800
16th to endDay
10%5%244245%5%6%49%
2225
April1st to 15thDay
11%5%25%42435%8%46%
2151
16th to endDay
8%42332446%8%51%
2160
May1st to 15thDay
9%324325%5%6%9%47%
2151
16th to endDay
7%424445%5%7%9%43%
2431
June1st to 15thDay
6%425%6%28%7%10%12%33%
2340
16th to endDay
7%416%6%5%6%8%8%12%31%
2340
July1st to 15thDay
7%426%10%49%7%9%12%25%
2270
16th to endDay
7%5%36%7%6%8%7%8%11%27%
2276
August1st to 15thDay
7%425%7%5%9%7%9%12%28%
2160
16th to endDay
11%5%26%7%5%6%7%7%8%30%
2292
September1st to 15thDay
10%425%6%35%6%8%10%35%
2103
16th to endDay
6%4245%35%5%5%7%47%
1980
October1st to 15thDay
6%31342345%8%55%
1980
16th to endDay
8%31232336%5%58%
1959
November1st to 15thDay
8%313323446%57%
1738
16th to endDay
7%313433346%57%
1755
December1st to 15thDay
11%7%35%42434447%
1755
16th to endDay
19%8%36%5%23436%35%
1872
January1st to 15thNight
12%6%235%34446%46%
2354
16th to endNight
18%5%24423345%45%
2364
February1st to 15thNight
13%5%23323346%50%
2103
16th to endNight
15%6%24423446%44%
1893
March1st to 15thNight
13%6%2442445%6%44%
2160
16th to endNight
9%5%24314446%52%
2007
April1st to 15thNight
10%42342446%7%49%
1797
16th to endNight
7%31322335%7%59%
1800
May1st to 15thNight
8%424323448%52%
1796
16th to endNight
5%3134245%7%11%49%
1682
June1st to 15thNight
5%425%3346%8%14%42%
1620
16th to endNight
6%324437%6%9%12%40%
1620
July1st to 15thNight
33245%35%7%8%13%42%
1686
16th to endNight
32145%47%8%9%13%38%
1892
August1st to 15thNight
33235%36%7%9%14%39%
1800
16th to endNight
7%435%5%36%6%6%11%38%
1910
September1st to 15thNight
6%415%5%35%7%7%12%39%
1843
16th to endNight
9%42442446%8%46%
1980
October1st to 15thNight
6%313423348%57%
1980
16th to endNight
9%313313235%61%
2262
November1st to 15thNight
7%3145%24345%56%
2447
16th to endNight
7%314324346%55%
2535
December1st to 15thNight
12%5%24434445%47%
2535
16th to endNight
16%7%35%6%2445%5%37%
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
37%5%8%16%21%9%
1912
16th to endDay
42%3415%23%10%
1964
February1st to 15thDay
35%39%17%21%11%
1752
16th to endDay
39%5%7%16%22%8%
1580
March1st to 15thDay
38%6%8%20%19%7%
1800
16th to endDay
35%5%11%18%21%7%
2226
April1st to 15thDay
35%5%9%19%20%8%
2151
16th to endDay
28%6%14%23%20%6%
2160
May1st to 15thDay
31%8%13%19%17%8%
2151
16th to endDay
33%9%14%23%16%2
2435
June1st to 15thDay
37%9%19%23%9%1
2340
16th to endDay
40%11%19%19%8%
2340
July1st to 15thDay
45%16%20%12%4
2136
16th to endDay
44%14%20%17%2
2133
August1st to 15thDay
41%14%23%13%7%
2148
16th to endDay
47%12%17%14%6%2
2292
September1st to 15thDay
39%11%17%16%11%4
2103
16th to endDay
33%8%13%18%17%7%
1980
October1st to 15thDay
26%6%12%18%22%13%
1980
16th to endDay
26%46%16%26%20%
1959
November1st to 15thDay
28%48%18%28%11%
1738
16th to endDay
27%48%18%24%17%
1755
December1st to 15thDay
39%5%8%18%20%7%
1755
16th to endDay
50%46%18%15%4
1872
January1st to 15thNight
38%48%14%25%9%
2354
16th to endNight
41%36%13%23%10%
2364
February1st to 15thNight
34%45%19%22%13%
2112
16th to endNight
41%5%5%14%20%12%
1893
March1st to 15thNight
39%5%10%16%21%7%
2160
16th to endNight
32%411%20%21%9%
2007
April1st to 15thNight
33%6%12%16%22%9%
1797
16th to endNight
23%413%27%23%6%
1800
May1st to 15thNight
30%5%14%21%21%7%
1797
16th to endNight
27%8%18%23%19%2
1684
June1st to 15thNight
29%10%24%22%11%1
1620
16th to endNight
31%11%22%23%10%
1620
July1st to 15thNight
28%15%32%16%6%
1591
16th to endNight
30%15%29%21%2
1772
August1st to 15thNight
27%16%32%17%5%
1788
16th to endNight
38%12%24%15%6%3
1910
September1st to 15thNight
32%11%20%18%11%5%
1843
16th to endNight
33%7%15%20%16%7%
1980
October1st to 15thNight
24%5%11%20%21%15%
1980
16th to endNight
26%35%14%26%23%
2262
November1st to 15thNight
29%38%18%28%12%
2447
16th to endNight
28%47%18%23%17%
2535
December1st to 15thNight
38%48%19%21%7%
2535
16th to endNight
47%38%19%14%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
17%16%29%22%9%4
135
16th to endDay
15%25%29%21%7%
109
February1st to 15thDay
13%20%33%24%8%
90
16th to endDay
8%19%38%27%6%
81
March1st to 15thDay
21%11%42%21%31
90
16th to endDay
16%7%22%32%17%2
249
April1st to 15thDay
18%11%23%21%24%1
270
16th to endDay
8%423%30%25%6%
270
May1st to 15thDay
8%6%19%27%29%9%
288
16th to endDay
10%113%32%20%21%
331
June1st to 15thDay
11%8%22%31%25%
315
16th to endDay
12%1417%32%30%
315
July1st to 15thDay
4311%38%41%
305
16th to endDay
7%312%37%39%
326
August1st to 15thDay
10%314%30%40%
313
16th to endDay
11%414%38%30%
332
September1st to 15thDay
7%211%19%31%27%
315
16th to endDay
11%334%32%16%
314
October1st to 15thDay
9%111%33%31%12%
315
16th to endDay
11%7%18%32%19%10%
183
November1st to 15thDay
17%122%36%19%2
135
16th to endDay
5%11%28%31%17%6%
135
December1st to 15thDay
20%8%34%25%10%2
135
16th to endDay
30%9%22%25%12%
144
January1st to 15thNight
15%12%30%31%9%
780
16th to endNight
21%11%29%29%8%
788
February1st to 15thNight
15%10%34%29%9%
704
16th to endNight
18%11%34%28%7%
631
March1st to 15thNight
15%10%30%33%9%
720
16th to endNight
12%7%25%35%17%1
624
April1st to 15thNight
12%5%26%33%19%1
539
16th to endNight
10%220%40%23%1
540
May1st to 15thNight
9%217%39%27%2
540
16th to endNight
6%12%31%42%6%
563
June1st to 15thNight
7%1429%45%11%
540
16th to endNight
6%421%48%18%
540
July1st to 15thNight
3215%50%27%
510
16th to endNight
3215%48%29%
564
August1st to 15thNight
4110%51%32%
539
16th to endNight
10%1317%44%22%
573
September1st to 15thNight
6%19%19%42%19%
583
16th to endNight
11%7%29%40%9%
717
October1st to 15thNight
8%216%33%31%6%
720
16th to endNight
10%421%29%28%4
768
November1st to 15thNight
10%421%39%21%3
760
16th to endNight
9%8%25%36%18%1
780
December1st to 15thNight
15%9%28%30%15%1
780
16th to endNight
21%7%31%27%10%
832
Page generated at 2018-01-21 11:19:31. Version ac04

Copyright 2018 A. Danko


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