Auburn-Opelika Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Auburn-Opelika Airport clear sky chart from 2005-11-05 to 2018-03-11.

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
50%
16094
23%
49111
17%
16052
58%
16052
29%
29940

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
27%
780
24%
2522
11%
776
43%
776
23%
1541
January16th to endNight
29%
832
26%
2551
13%
832
42%
832
24%
1606
February1st to 15thNight
33%
762
25%
2290
12%
760
46%
760
26%
1431
February16th to endNight
28%
683
25%
2049
11%
683
42%
683
27%
1272
March1st to 15thNight
34%
764
24%
2234
11%
764
45%
764
29%
1356
March16th to endNight
39%
768
23%
2112
12%
768
47%
768
32%
1277
April1st to 15thNight
46%
572
25%
1830
19%
572
55%
572
32%
1033
April16th to endNight
49%
540
29%
1776
22%
540
60%
540
36%
944
May1st to 15thNight
55%
539
23%
1620
16%
539
62%
539
34%
954
May16th to endNight
65%
561
23%
1682
18%
561
69%
561
33%
1025
June1st to 15thNight
68%
540
14%
1620
12%
540
69%
540
26%
1087
June16th to endNight
76%
540
17%
1620
16%
540
77%
540
31%
995
July1st to 15thNight
77%
510
11%
1530
11%
510
77%
510
27%
995
July16th to endNight
75%
564
16%
1595
16%
531
76%
531
29%
1026
August1st to 15thNight
71%
539
15%
1762
17%
536
71%
536
23%
1149
August16th to endNight
64%
573
17%
1910
19%
573
65%
573
22%
1260
September1st to 15thNight
66%
670
20%
1930
19%
670
67%
670
28%
1281
September16th to endNight
61%
717
26%
1980
20%
717
65%
717
31%
1254
October1st to 15thNight
58%
720
32%
1980
24%
720
66%
720
42%
1130
October16th to endNight
52%
768
36%
2273
28%
768
64%
768
41%
1228
November1st to 15thNight
53%
760
29%
2471
24%
760
63%
760
37%
1324
November16th to endNight
42%
780
29%
2535
20%
780
56%
780
32%
1414
December1st to 15thNight
38%
780
24%
2535
16%
780
49%
780
26%
1542
December16th to endNight
33%
832
20%
2704
14%
832
42%
832
20%
1816

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%35%5%6%7%41%
49506
Night
11%5%2442445%7%46%
49312
TransparencyDay
39%7%11%17%17%6%
49207
Night
35%6%11%18%19%8%
49115
SeeingDay
14%6%19%24%22%13%
5868
Night
13%6%23%29%22%4
16099

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
15%6%24334345%45%
1746
16th to endDay
17%5%35%323346%44%
2022
February1st to 15thDay
17%5%35%5%23346%42%
1900
16th to endDay
16%7%26%433446%42%
1710
March1st to 15thDay
16%6%15%42345%5%44%
1963
16th to endDay
15%5%234245%46%45%
2111
April1st to 15thDay
14%42432445%8%44%
2127
16th to endDay
10%32442445%8%49%
2182
May1st to 15thDay
10%4245%345%6%7%44%
2331
16th to endDay
7%425%5%35%5%7%9%43%
2431
June1st to 15thDay
8%5%26%8%47%7%8%9%31%
2340
16th to endDay
6%425%6%47%7%8%10%37%
2340
July1st to 15thDay
9%5%25%8%5%7%8%8%11%26%
2340
16th to endDay
9%5%36%8%5%7%7%9%10%26%
2465
August1st to 15thDay
9%5%26%6%5%8%7%8%12%26%
2184
16th to endDay
14%6%36%6%47%5%7%9%28%
2292
September1st to 15thDay
11%5%26%6%37%7%6%7%35%
2016
16th to endDay
12%5%25%6%3445%6%42%
1980
October1st to 15thDay
11%5%2342245%6%51%
1980
16th to endDay
10%313323335%60%
1947
November1st to 15thDay
10%42342443455%
1717
16th to endDay
14%41332335%5%52%
1755
December1st to 15thDay
17%424425%446%43%
1755
16th to endDay
23%7%35%5%22345%36%
1872
January1st to 15thNight
15%7%24423246%46%
2522
16th to endNight
19%6%23323335%44%
2551
February1st to 15thNight
16%5%34423345%46%
2283
16th to endNight
14%5%25%423445%46%
2049
March1st to 15thNight
12%5%23324436%49%
2234
16th to endNight
10%5%2442436%7%49%
2112
April1st to 15thNight
12%31442345%8%49%
1830
16th to endNight
8%414324338%55%
1776
May1st to 15thNight
8%425%3245%6%7%49%
1619
16th to endNight
5%4145%36%5%6%8%47%
1682
June1st to 15thNight
6%426%6%47%6%7%11%35%
1620
16th to endNight
43245%36%6%8%12%41%
1620
July1st to 15thNight
4425%446%8%9%13%35%
1620
16th to endNight
5%325%5%46%6%9%13%36%
1703
August1st to 15thNight
5%426%6%37%7%8%13%33%
1773
16th to endNight
12%6%25%5%35%5%6%10%36%
1910
September1st to 15thNight
9%425%435%7%7%8%41%
1930
16th to endNight
8%5%25%4345%5%7%47%
1980
October1st to 15thNight
8%324313347%56%
1980
16th to endNight
8%423312235%61%
2273
November1st to 15thNight
9%314323346%58%
2471
16th to endNight
11%424323346%54%
2535
December1st to 15thNight
15%5%25%5%23335%46%
2535
16th to endNight
20%6%26%5%24346%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
41%37%16%25%5%
1747
16th to endDay
41%36%14%24%10%
2022
February1st to 15thDay
43%36%18%21%6%
1902
16th to endDay
42%45%18%20%7%
1710
March1st to 15thDay
40%48%16%19%8%
1963
16th to endDay
38%5%10%19%20%5%
2112
April1st to 15thDay
37%5%8%21%19%8%
2127
16th to endDay
32%5%10%19%25%5%
2182
May1st to 15thDay
36%6%11%17%21%5%
2331
16th to endDay
33%10%13%25%14%3
2435
June1st to 15thDay
42%11%15%18%9%1
2340
16th to endDay
35%11%17%20%11%2
2340
July1st to 15thDay
43%14%20%14%5%1
2201
16th to endDay
45%13%18%15%6%
2310
August1st to 15thDay
44%13%17%15%7%
2171
16th to endDay
47%11%16%13%9%1
2292
September1st to 15thDay
45%8%12%15%13%4
2016
16th to endDay
39%7%9%19%18%4
1980
October1st to 15thDay
32%5%9%19%23%9%
1980
16th to endDay
27%35%15%31%15%
1947
November1st to 15thDay
32%36%17%25%13%
1717
16th to endDay
33%37%15%26%12%
1755
December1st to 15thDay
39%49%18%18%7%
1755
16th to endDay
51%37%17%13%6%
1872
January1st to 15thNight
40%35%17%25%7%
2522
16th to endNight
41%35%14%22%11%
2551
February1st to 15thNight
39%35%19%20%12%
2292
16th to endNight
38%46%17%21%11%
2049
March1st to 15thNight
35%48%19%21%9%
2234
16th to endNight
32%5%11%19%23%7%
2112
April1st to 15thNight
31%5%10%20%22%10%
1830
16th to endNight
28%410%24%22%9%
1776
May1st to 15thNight
31%6%12%18%24%6%
1620
16th to endNight
32%7%13%23%16%6%
1684
June1st to 15thNight
39%10%17%18%13%
1620
16th to endNight
30%10%19%21%13%3
1620
July1st to 15thNight
32%14%25%18%7%2
1530
16th to endNight
34%11%25%21%7%
1595
August1st to 15thNight
37%12%19%20%7%2
1762
16th to endNight
41%9%17%15%13%2
1910
September1st to 15thNight
35%11%12%19%14%5%
1930
16th to endNight
36%6%12%19%18%6%
1980
October1st to 15thNight
27%5%10%21%22%12%
1980
16th to endNight
26%35%13%32%17%
2273
November1st to 15thNight
29%37%16%27%15%
2471
16th to endNight
32%37%16%25%14%
2535
December1st to 15thNight
39%49%18%21%6%
2535
16th to endNight
47%46%19%15%6%
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
16%19%39%17%43
135
16th to endDay
16%22%40%11%6%1
144
February1st to 15thDay
29%18%31%14%5%
135
16th to endDay
18%13%40%27%
120
March1st to 15thDay
18%20%37%14%6%1
179
16th to endDay
17%9%31%24%14%1
288
April1st to 15thDay
18%12%24%22%20%2
270
16th to endDay
14%426%25%22%6%
270
May1st to 15thDay
14%7%24%21%19%11%
288
16th to endDay
11%312%33%25%14%
331
June1st to 15thDay
12%11%23%27%24%
315
16th to endDay
7%110%27%22%30%
315
July1st to 15thDay
7%7%19%33%31%
305
16th to endDay
7%15%20%34%30%
326
August1st to 15thDay
13%5%22%37%21%
313
16th to endDay
16%421%35%20%
332
September1st to 15thDay
13%28%25%28%21%
315
16th to endDay
12%113%29%30%11%
314
October1st to 15thDay
13%320%31%22%7%
315
16th to endDay
11%8%24%23%22%8%
309
November1st to 15thDay
20%428%31%12%2
135
16th to endDay
6%8%31%31%17%3
135
December1st to 15thDay
24%14%31%21%8%
135
16th to endDay
31%10%27%25%4
144
January1st to 15thNight
19%14%32%25%7%
780
16th to endNight
22%13%31%27%5%
832
February1st to 15thNight
18%11%31%30%7%
764
16th to endNight
16%12%38%27%5%
683
March1st to 15thNight
14%12%35%29%7%
764
16th to endNight
13%12%29%26%16%
768
April1st to 15thNight
13%7%29%29%19%1
572
16th to endNight
11%5%29%32%20%1
540
May1st to 15thNight
8%324%32%25%5%
540
16th to endNight
8%16%34%33%6%
563
June1st to 15thNight
8%10%35%36%9%
540
16th to endNight
5%7%26%45%14%
540
July1st to 15thNight
5%1328%44%17%
510
16th to endNight
7%5%22%48%15%
564
August1st to 15thNight
7%6%27%43%15%
539
16th to endNight
14%27%22%37%15%
573
September1st to 15thNight
11%11%28%37%11%
670
16th to endNight
11%114%35%33%4
717
October1st to 15thNight
10%322%34%24%4
720
16th to endNight
11%7%24%28%25%3
768
November1st to 15thNight
11%5%26%32%21%2
760
16th to endNight
13%9%30%29%15%1
780
December1st to 15thNight
18%8%28%31%11%1
780
16th to endNight
24%9%28%29%7%
832
Page generated at 2018-03-12 12:28:12. Version ac04

Copyright 2018 A. Danko


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