Oak Mountain State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oak Mountain State Park clear sky chart from 2005-11-06 to 2024-01-15.

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
49%
23479
23%
74460
17%
23425
57%
23425
28%
45501

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
26%
760
23%
2459
10%
757
41%
757
23%
1530
January11th to 20thNight
29%
737
24%
2307
12%
737
42%
737
19%
1536
January21st to endNight
27%
792
29%
2376
13%
792
43%
792
24%
1529
February1st to 10thNight
30%
720
24%
2160
11%
720
41%
720
24%
1405
February11th to 20thNight
26%
703
21%
2098
9%
699
37%
699
23%
1381
February21st to endNight
25%
592
21%
1776
9%
592
36%
592
22%
1190
March1st to 10thNight
33%
720
24%
2160
14%
720
41%
720
28%
1332
March11th to 20thNight
32%
720
20%
2062
9%
720
41%
720
25%
1354
March21st to endNight
35%
702
25%
2088
13%
702
45%
702
28%
1294
April1st to 10thNight
41%
540
26%
1800
19%
540
51%
540
28%
1055
April11th to 20thNight
40%
533
27%
1775
18%
533
53%
533
30%
1011
April21st to endNight
49%
540
27%
1800
20%
540
60%
540
32%
986
May1st to 10thNight
51%
540
25%
1661
18%
540
60%
540
36%
965
May11th to 20thNight
57%
531
19%
1592
14%
531
62%
531
30%
996
May21st to endNight
72%
582
23%
1744
20%
582
74%
582
34%
1037
June1st to 10thNight
68%
540
16%
1620
15%
540
68%
540
26%
1054
June11th to 20thNight
77%
540
19%
1620
16%
540
79%
540
42%
887
June21st to endNight
72%
540
18%
1620
16%
540
73%
540
33%
984
July1st to 10thNight
75%
525
13%
1575
12%
525
76%
525
26%
1037
July11th to 20thNight
76%
522
14%
1566
15%
522
76%
522
29%
1009
July21st to endNight
76%
591
15%
1730
16%
558
77%
558
29%
1106
August1st to 10thNight
79%
537
15%
1778
18%
534
80%
534
31%
1055
August11th to 20thNight
73%
534
15%
1776
18%
534
73%
534
26%
1139
August21st to endNight
68%
594
20%
1980
25%
594
68%
594
23%
1295
September1st to 10thNight
69%
566
23%
1826
24%
566
69%
566
29%
1124
September11th to 20thNight
65%
720
23%
1980
20%
720
66%
720
31%
1261
September21st to endNight
67%
720
30%
1980
23%
720
71%
720
40%
1146
October1st to 10thNight
60%
720
32%
1980
24%
720
66%
720
43%
1112
October11th to 20thNight
55%
720
35%
1980
25%
720
63%
720
39%
1156
October21st to endNight
50%
792
30%
2474
27%
792
57%
792
33%
1424
November1st to 10thNight
55%
740
28%
2406
25%
740
63%
740
36%
1291
November11th to 20thNight
46%
760
29%
2470
22%
760
58%
760
33%
1375
November21st to endNight
41%
760
25%
2470
18%
760
53%
760
28%
1466
December1st to 10thNight
35%
760
24%
2470
16%
760
46%
760
22%
1571
December11th to 20thNight
34%
759
24%
2901
15%
758
43%
758
21%
1756
December21st to endNight
29%
827
14%
4400
14%
817
39%
817
13%
2652

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%35%5%35%5%6%8%42%
74831
Night
12%6%25%5%345%5%8%46%
74946
TransparencyDay
39%7%11%19%19%5%
74558
Night
36%6%11%19%20%7%
74738
SeeingDay
15%9%22%24%19%10%
13440
Night
14%8%23%29%22%4
23491

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
18%8%35%423446%43%
1706
11th to 20thDay
20%9%35%32334443%
1737
21st to endDay
17%7%25%433446%46%
1980
February1st to 10thDay
18%10%36%5%34446%38%
1800
11th to 20thDay
23%7%35%42434440%
1748
21st to endDay
21%8%45%6%34445%37%
1480
March1st to 10thDay
15%7%36%424346%46%
1800
11th to 20thDay
16%8%47%5%345%5%6%37%
1898
21st to endDay
14%7%35%5%35%5%5%7%40%
2281
April1st to 10thDay
12%6%25%6%3446%8%46%
2160
11th to 20thDay
12%5%35%5%35%45%6%46%
2134
21st to endDay
8%5%245%35%46%9%50%
2160
May1st to 10thDay
10%5%24435%5%5%8%47%
2296
11th to 20thDay
9%6%25%5%35%6%6%9%43%
2301
21st to endDay
9%5%26%6%36%5%5%9%43%
2531
June1st to 10thDay
9%7%36%7%5%6%7%7%10%33%
2340
11th to 20thDay
6%4246%46%7%7%11%43%
2340
21st to endDay
6%426%6%46%7%7%12%39%
2340
July1st to 10thDay
9%5%36%7%5%7%8%9%10%32%
2340
11th to 20thDay
8%5%36%7%5%8%9%10%12%29%
2340
21st to endDay
6%336%7%5%9%9%9%12%32%
2481
August1st to 10thDay
6%425%6%5%8%10%9%13%31%
2148
11th to 20thDay
11%6%26%7%5%7%7%8%9%32%
2125
21st to endDay
11%6%37%6%5%6%7%9%9%31%
2376
September1st to 10thDay
9%6%37%7%37%5%6%8%41%
2114
11th to 20thDay
13%7%25%5%35%5%5%7%42%
1980
21st to endDay
9%5%25%5%44447%51%
1980
October1st to 10thDay
9%425%435%45%6%54%
1980
11th to 20thDay
9%42443335%7%55%
1980
21st to endDay
12%5%25%424346%54%
1876
November1st to 10thDay
12%6%24433436%55%
1672
11th to 20thDay
13%6%24324346%52%
1710
21st to endDay
14%6%35%4345%46%45%
1710
December1st to 10thDay
20%7%45%5%2445%6%38%
1710
11th to 20thDay
17%8%35%6%3443442%
2153
21st to endDay
19%10%46%5%3435%7%36%
3124
January1st to 10thNight
17%8%35%423445%45%
2459
11th to 20thNight
16%9%46%5%34446%40%
2307
21st to endNight
17%7%35%434445%45%
2376
February1st to 10thNight
17%8%36%5%33446%42%
2160
11th to 20thNight
20%7%35%423435%43%
2098
21st to endNight
20%6%25%5%3445%7%39%
1776
March1st to 10thNight
15%7%25%424447%46%
2160
11th to 20thNight
15%7%344345%6%7%42%
2062
21st to endNight
13%5%245%345%5%8%45%
2088
April1st to 10thNight
11%425%5%345%6%8%47%
1800
11th to 20thNight
13%5%25%42435%7%50%
1775
21st to endNight
9%4245%4445%7%54%
1800
May1st to 10thNight
8%325%5%25%46%9%51%
1661
11th to 20thNight
8%5%346%36%5%7%8%45%
1592
21st to endNight
6%3245%36%6%8%10%47%
1744
June1st to 10thNight
5%5%25%6%47%8%8%11%37%
1620
11th to 20thNight
4312436%6%9%11%51%
1620
21st to endNight
5%415%6%35%6%8%12%43%
1620
July1st to 10thNight
7%5%26%5%47%8%9%10%37%
1620
11th to 20thNight
5%435%6%46%7%8%12%40%
1620
21st to endNight
4426%6%47%6%9%10%41%
1832
August1st to 10thNight
43246%46%8%9%15%40%
1790
11th to 20thNight
7%5%36%6%46%6%6%13%39%
1776
21st to endNight
9%6%26%6%47%6%6%9%39%
1980
September1st to 10thNight
8%427%6%36%5%7%9%43%
1826
11th to 20thNight
11%5%25%5%345%6%8%47%
1980
21st to endNight
6%5%25%5%245%6%6%54%
1980
October1st to 10thNight
8%424423446%60%
1980
11th to 20thNight
11%424423446%56%
1980
21st to endNight
14%6%2341433455%
2474
November1st to 10thNight
11%5%14323446%58%
2406
11th to 20thNight
12%5%34324346%54%
2470
21st to endNight
13%6%25%5%35%45%6%48%
2470
December1st to 10thNight
18%6%35%424447%42%
2470
11th to 20thNight
17%7%25%32343447%
3042
21st to endNight
18%8%36%5%345%6%7%35%
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
44%47%17%24%5%
1707
11th to 20thDay
46%37%18%21%5%
1737
21st to endDay
40%45%20%25%6%
1980
February1st to 10thDay
48%37%19%18%4
1800
11th to 20thDay
48%45%18%19%7%
1758
21st to endDay
49%5%6%11%21%8%
1480
March1st to 10thDay
41%48%16%21%10%
1800
11th to 20thDay
47%6%10%14%17%5%
1898
21st to endDay
42%6%10%20%20%3
2281
April1st to 10thDay
36%5%11%21%19%8%
2160
11th to 20thDay
39%5%7%18%24%7%
2134
21st to endDay
31%6%10%24%26%3
2160
May1st to 10thDay
34%6%10%22%23%4
2296
11th to 20thDay
36%7%16%23%15%3
2305
21st to endDay
37%8%12%23%18%3
2531
June1st to 10thDay
42%9%15%20%14%1
2340
11th to 20thDay
31%10%18%25%14%2
2340
21st to endDay
35%10%19%23%10%4
2340
July1st to 10thDay
39%14%19%18%9%1
2275
11th to 20thDay
41%14%20%15%9%1
2271
21st to endDay
39%14%20%19%9%
2342
August1st to 10thDay
36%14%20%23%6%1
2136
11th to 20thDay
43%11%17%16%10%3
2125
21st to endDay
44%10%16%17%10%3
2376
September1st to 10thDay
40%8%13%17%17%5%
2114
11th to 20thDay
40%8%11%18%19%4
1980
21st to endDay
33%6%9%21%23%8%
1980
October1st to 10thDay
32%5%10%19%25%10%
1980
11th to 20thDay
30%48%22%28%8%
1980
21st to endDay
34%45%16%31%10%
1876
November1st to 10thDay
34%46%17%29%11%
1672
11th to 20thDay
35%36%19%26%11%
1710
21st to endDay
39%5%8%17%23%8%
1710
December1st to 10thDay
46%6%9%15%19%6%
1710
11th to 20thDay
47%36%16%22%5%
2150
21st to endDay
48%38%18%20%2
3124
January1st to 10thNight
41%47%19%24%5%
2459
11th to 20thNight
46%5%6%18%20%5%
2307
21st to endNight
43%3418%25%7%
2376
February1st to 10thNight
44%37%18%20%7%
2160
11th to 20thNight
45%45%18%19%10%
2099
21st to endNight
45%5%8%14%18%9%
1776
March1st to 10thNight
39%47%16%22%12%
2160
11th to 20thNight
41%6%11%16%20%6%
2062
21st to endNight
38%5%8%25%19%5%
2088
April1st to 10thNight
35%6%11%21%20%8%
1800
11th to 20thNight
34%48%20%23%11%
1775
21st to endNight
31%5%11%24%23%6%
1800
May1st to 10thNight
29%7%10%23%25%6%
1661
11th to 20thNight
34%9%17%20%17%3
1593
21st to endNight
28%11%12%26%18%4
1745
June1st to 10thNight
35%12%14%20%17%1
1620
11th to 20thNight
23%8%23%28%15%3
1620
21st to endNight
30%11%18%21%16%4
1620
July1st to 10thNight
36%12%19%21%9%3
1575
11th to 20thNight
32%13%23%20%9%2
1566
21st to endNight
32%13%23%21%10%1
1730
August1st to 10thNight
28%13%21%29%9%1
1778
11th to 20thNight
35%12%21%16%11%4
1776
21st to endNight
40%10%15%19%12%4
1980
September1st to 10thNight
36%8%16%18%17%5%
1826
11th to 20thNight
34%9%11%20%20%5%
1980
21st to endNight
28%6%11%22%24%8%
1980
October1st to 10thNight
26%5%9%21%25%13%
1980
11th to 20thNight
30%48%21%25%12%
1980
21st to endNight
34%36%15%29%13%
2474
November1st to 10thNight
29%48%17%27%14%
2406
11th to 20thNight
32%46%18%26%14%
2470
21st to endNight
37%5%7%18%24%9%
2470
December1st to 10thNight
42%5%9%18%21%5%
2470
11th to 20thNight
41%47%14%29%6%
3044
21st to endNight
47%49%18%20%3
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
27%20%31%16%4
270
11th to 20thDay
26%19%31%15%8%
252
21st to endDay
23%27%38%10%21
264
February1st to 10thDay
29%20%37%13%2
240
11th to 20thDay
40%16%29%14%
240
21st to endDay
26%20%44%9%1
198
March1st to 10thDay
26%22%32%15%5%
240
11th to 20thDay
22%17%36%16%7%1
338
21st to endDay
23%18%30%20%9%
462
April1st to 10thDay
19%14%31%24%11%1
420
11th to 20thDay
18%14%30%23%12%3
412
21st to endDay
13%11%31%29%13%3
420
May1st to 10thDay
12%10%25%32%16%5%
423
11th to 20thDay
9%427%29%21%11%
447
21st to endDay
11%5%16%31%20%17%
485
June1st to 10thDay
12%5%14%32%23%14%
450
11th to 20thDay
7%414%24%29%22%
450
21st to endDay
8%413%25%32%19%
450
July1st to 10thDay
9%27%25%36%22%
445
11th to 20thDay
6%27%22%32%31%
444
21st to endDay
6%28%22%36%27%
488
August1st to 10thDay
6%27%27%31%26%
446
11th to 20thDay
9%26%30%35%19%
439
21st to endDay
14%49%24%31%19%
495
September1st to 10thDay
8%410%31%31%16%
450
11th to 20thDay
11%6%13%26%33%12%
450
21st to endDay
11%316%30%32%8%
450
October1st to 10thDay
11%5%22%32%24%6%
450
11th to 20thDay
12%6%26%32%22%1
450
21st to endDay
19%13%23%30%14%2
325
November1st to 10thDay
17%9%32%27%10%4
270
11th to 20thDay
17%14%39%24%6%
270
21st to endDay
15%16%37%21%10%1
270
December1st to 10thDay
28%17%28%23%3
270
11th to 20thDay
24%18%36%15%6%1
270
21st to endDay
26%19%32%19%4
297
January1st to 10thNight
21%15%35%23%5%
760
11th to 20thNight
21%17%29%25%8%
737
21st to endNight
19%16%36%26%4
792
February1st to 10thNight
21%11%35%29%4
720
11th to 20thNight
25%14%32%25%4
703
21st to endNight
21%15%36%25%3
592
March1st to 10thNight
18%13%32%32%5%
720
11th to 20thNight
17%13%34%25%10%1
720
21st to endNight
16%12%33%28%11%
702
April1st to 10thNight
13%10%34%30%14%
540
11th to 20thNight
15%10%30%29%14%2
533
21st to endNight
12%8%28%35%16%2
540
May1st to 10thNight
9%7%28%31%23%3
540
11th to 20thNight
9%322%34%28%4
531
21st to endNight
8%211%34%39%7%
584
June1st to 10thNight
9%29%40%35%6%
540
11th to 20thNight
5%19%28%44%13%
540
21st to endNight
5%19%29%44%12%
540
July1st to 10thNight
7%15%25%46%15%
525
11th to 20thNight
6%421%48%21%
522
21st to endNight
6%16%25%47%15%
591
August1st to 10thNight
5%1425%48%18%
537
11th to 20thNight
8%26%29%47%8%
534
21st to endNight
12%36%26%41%12%
594
September1st to 10thNight
9%37%31%41%9%
566
11th to 20thNight
12%313%29%38%6%
720
21st to endNight
9%115%32%39%3
720
October1st to 10thNight
9%422%32%28%6%
720
11th to 20thNight
11%6%23%34%23%2
720
21st to endNight
16%7%21%33%21%2
792
November1st to 10thNight
12%8%20%37%19%4
740
11th to 20thNight
14%9%28%34%13%1
760
21st to endNight
15%10%29%33%12%1
760
December1st to 10thNight
21%12%26%30%9%1
760
11th to 20thNight
24%10%29%27%9%
760
21st to endNight
24%12%30%28%7%
836
Page generated at 2024-01-11 21:33:45. Version ac07

Copyright 2024 Attilla Danko


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