Great Smokey Mountains National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Great Smokey Mountains National Park clear sky chart from 2005-11-06 to 2024-02-20.

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
39%
24047
17%
79833
12%
23929
45%
23929
19%
54372

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
22%
757
16%
4042
10%
737
32%
737
8%
2791
January11th to 20thNight
17%
760
22%
3975
8%
740
27%
740
8%
2612
January21st to endNight
19%
835
12%
4469
8%
814
32%
814
9%
3102
February1st to 10thNight
25%
760
19%
2314
10%
760
35%
760
18%
1627
February11th to 20thNight
14%
742
14%
2214
5%
739
22%
739
13%
1646
February21st to endNight
18%
592
18%
1776
8%
592
27%
592
13%
1330
March1st to 10thNight
23%
720
19%
2080
10%
720
31%
720
18%
1448
March11th to 20thNight
25%
720
14%
1980
8%
720
29%
720
17%
1468
March21st to endNight
24%
792
14%
2178
6%
792
30%
792
18%
1574
April1st to 10thNight
28%
720
18%
1980
9%
720
36%
720
24%
1323
April11th to 20thNight
34%
533
22%
1737
12%
533
46%
533
22%
1109
April21st to endNight
37%
540
21%
1620
11%
540
46%
540
24%
1066
May1st to 10thNight
35%
540
14%
1620
7%
540
40%
540
20%
1116
May11th to 20thNight
45%
531
12%
1593
8%
531
48%
531
20%
1140
May21st to endNight
55%
582
14%
1744
10%
582
57%
582
22%
1201
June1st to 10thNight
55%
540
13%
1620
10%
540
57%
540
22%
1115
June11th to 20thNight
66%
540
11%
1620
9%
540
67%
540
28%
1059
June21st to endNight
60%
540
15%
1620
12%
540
61%
540
25%
1089
July1st to 10thNight
61%
525
10%
1575
9%
525
62%
525
20%
1140
July11th to 20thNight
65%
522
10%
1566
8%
522
66%
522
24%
1081
July21st to endNight
64%
591
11%
1672
10%
558
65%
558
20%
1184
August1st to 10thNight
69%
537
12%
1600
12%
534
68%
534
24%
1107
August11th to 20thNight
61%
534
14%
1606
14%
534
61%
534
19%
1168
August21st to endNight
61%
594
13%
1980
15%
594
61%
594
19%
1345
September1st to 10thNight
60%
714
17%
1974
15%
714
60%
714
25%
1344
September11th to 20thNight
56%
720
18%
1980
16%
720
57%
720
25%
1358
September21st to endNight
54%
720
24%
1980
19%
720
58%
720
28%
1288
October1st to 10thNight
51%
720
26%
1980
23%
720
54%
720
32%
1241
October11th to 20thNight
39%
720
24%
2137
18%
720
47%
720
26%
1356
October21st to endNight
42%
792
28%
2376
21%
792
51%
792
29%
1459
November1st to 10thNight
46%
740
24%
2378
22%
740
53%
740
27%
1435
November11th to 20thNight
38%
760
24%
2470
19%
760
48%
760
25%
1528
November21st to endNight
35%
760
23%
2470
15%
760
46%
760
22%
1583
December1st to 10thNight
25%
760
15%
2470
10%
760
32%
760
13%
1841
December11th to 20thNight
26%
759
19%
2986
13%
759
37%
759
14%
2054
December21st to endNight
23%
835
10%
4451
9%
817
32%
817
8%
3044

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
14%9%47%6%45%5%6%7%33%
78743
Night
13%11%47%6%345%5%7%35%
80452
TransparencyDay
47%9%10%17%14%3
78466
Night
45%9%11%17%15%3
80248
SeeingDay
19%15%25%22%13%6%
13902
Night
18%12%23%27%17%3
24055

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
13%11%5%8%6%45%6%6%6%29%
2836
11th to 20thDay
13%12%6%12%6%33445%33%
2840
21st to endDay
15%15%6%8%4235%5%5%33%
3124
February1st to 10thDay
16%10%6%9%6%35%5%4432%
1862
11th to 20thDay
19%12%5%8%6%33446%31%
1838
21st to endDay
19%10%5%9%43445%6%32%
1480
March1st to 10thDay
15%8%6%7%5%345%48%36%
1879
11th to 20thDay
18%12%48%6%345%46%30%
1980
21st to endDay
15%14%5%6%6%3445%6%31%
2178
April1st to 10thDay
11%10%36%6%35%5%5%6%39%
1994
11th to 20thDay
15%9%45%5%35%5%5%7%38%
2169
21st to endDay
16%9%36%7%35%5%46%37%
2340
May1st to 10thDay
15%8%36%7%45%6%5%7%35%
2340
11th to 20thDay
18%8%48%7%45%6%5%6%29%
2301
21st to endDay
15%8%37%7%46%6%6%9%28%
2531
June1st to 10thDay
12%8%38%8%5%7%6%7%9%28%
2340
11th to 20thDay
9%7%49%10%5%7%6%7%9%28%
2340
21st to endDay
12%7%37%8%47%7%7%9%30%
2340
July1st to 10thDay
13%9%48%8%6%8%8%7%9%20%
2340
11th to 20thDay
14%7%48%8%5%8%7%8%8%21%
2340
21st to endDay
13%7%48%9%5%8%8%7%9%22%
2547
August1st to 10thDay
14%7%38%8%5%8%7%8%9%23%
2327
11th to 20thDay
14%8%49%9%5%7%6%7%8%24%
2290
21st to endDay
14%8%48%9%5%7%7%6%8%24%
2363
September1st to 10thDay
13%7%48%7%36%7%6%7%32%
1980
11th to 20thDay
16%8%37%7%45%5%6%7%31%
1980
21st to endDay
14%7%35%6%45%5%6%6%39%
1980
October1st to 10thDay
12%7%26%5%345%5%6%44%
1980
11th to 20thDay
12%9%35%433346%48%
1822
21st to endDay
14%7%24435%246%48%
1980
November1st to 10thDay
11%8%3442335%6%52%
1695
11th to 20thDay
11%8%46%5%345%5%5%45%
1710
21st to endDay
12%9%46%5%25%45%6%42%
1710
December1st to 10thDay
17%13%48%6%35%35%5%31%
1710
11th to 20thDay
12%11%47%5%45%5%6%6%35%
2153
21st to endDay
12%11%7%9%6%34446%34%
3124
January1st to 10thNight
13%15%6%9%6%345%45%28%
4109
11th to 20thNight
18%12%48%6%4435%5%32%
4120
21st to endNight
16%19%6%7%5%2343431%
4532
February1st to 10thNight
14%11%5%8%6%35%45%5%34%
2314
11th to 20thNight
18%13%5%9%5%345%4331%
2213
21st to endNight
19%13%48%6%35%5%4428%
1776
March1st to 10thNight
14%11%6%8%6%34446%36%
2080
11th to 20thNight
15%15%5%8%6%3445%6%30%
1980
21st to endNight
13%12%5%8%6%35%45%5%33%
2178
April1st to 10thNight
13%10%45%6%33447%41%
1980
11th to 20thNight
12%10%46%5%34446%42%
1737
21st to endNight
15%8%35%5%35%447%40%
1620
May1st to 10thNight
14%11%45%5%35%5%5%8%35%
1620
11th to 20thNight
16%7%36%6%35%5%6%9%33%
1592
21st to endNight
10%7%36%8%46%7%7%9%33%
1744
June1st to 10thNight
10%7%36%6%46%7%8%9%33%
1620
11th to 20thNight
6%5%25%6%47%6%8%12%39%
1620
21st to endNight
10%7%37%5%46%6%7%9%36%
1620
July1st to 10thNight
11%7%47%7%47%7%8%9%29%
1620
11th to 20thNight
10%6%37%6%45%8%9%13%30%
1620
21st to endNight
8%7%37%6%47%8%9%11%31%
1771
August1st to 10thNight
11%6%35%6%46%6%8%10%36%
1611
11th to 20thNight
11%7%36%8%5%7%6%6%9%32%
1606
21st to endNight
12%7%38%6%46%7%7%9%32%
1980
September1st to 10thNight
12%7%46%6%35%6%7%7%37%
1974
11th to 20thNight
14%8%37%6%4446%6%39%
1980
21st to endNight
13%7%36%6%3445%6%44%
1980
October1st to 10thNight
14%9%24423446%49%
1980
11th to 20thNight
15%8%25%5%3444446%
2137
21st to endNight
12%9%35%434445%47%
2376
November1st to 10thNight
12%9%35%5%33345%47%
2378
11th to 20thNight
13%9%37%5%24445%44%
2470
21st to endNight
12%10%47%5%3445%6%41%
2470
December1st to 10thNight
16%14%6%9%6%4345%6%27%
2470
11th to 20thNight
13%14%6%10%5%34436%34%
3042
21st to endNight
13%13%8%11%7%345%6%6%24%
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
46%9%8%15%18%5%
2837
11th to 20thDay
51%8%6%14%18%3
2840
21st to endDay
50%7%7%16%18%2
3124
February1st to 10thDay
53%6%8%15%15%3
1862
11th to 20thDay
53%6%7%16%14%4
1848
21st to endDay
51%5%9%13%15%6%
1480
March1st to 10thDay
45%7%7%17%17%6%
1879
11th to 20thDay
52%8%10%14%14%3
1980
21st to endDay
53%6%11%18%11%2
2178
April1st to 10thDay
41%7%11%22%16%3
1994
11th to 20thDay
43%7%8%17%21%4
2169
21st to endDay
45%7%9%24%13%2
2340
May1st to 10thDay
45%9%11%21%11%3
2340
11th to 20thDay
50%12%11%16%9%1
2305
21st to endDay
45%14%13%18%10%1
2531
June1st to 10thDay
47%12%14%18%8%1
2340
11th to 20thDay
46%13%16%15%10%1
2340
21st to endDay
44%13%15%16%10%3
2340
July1st to 10thDay
51%15%14%15%6%
2275
11th to 20thDay
51%14%13%11%8%2
2271
21st to endDay
50%15%15%14%6%
2405
August1st to 10thDay
50%14%15%16%5%
2314
11th to 20thDay
53%11%14%13%8%
2290
21st to endDay
52%12%12%13%8%2
2363
September1st to 10thDay
45%10%12%16%14%3
1980
11th to 20thDay
48%9%9%18%14%2
1980
21st to endDay
41%9%11%19%16%5%
1980
October1st to 10thDay
37%8%9%21%21%5%
1980
11th to 20thDay
36%6%8%21%22%7%
1822
21st to endDay
35%6%7%23%22%6%
1980
November1st to 10thDay
33%5%7%19%28%8%
1695
11th to 20thDay
38%6%6%21%22%7%
1710
21st to endDay
40%6%7%20%21%5%
1710
December1st to 10thDay
52%8%7%16%14%3
1710
11th to 20thDay
44%8%10%14%18%5%
2150
21st to endDay
47%7%9%22%12%2
3124
January1st to 10thNight
50%10%6%12%15%6%
4109
11th to 20thNight
49%8%7%11%20%6%
4120
21st to endNight
54%7%7%11%17%5%
4532
February1st to 10thNight
49%6%10%16%16%3
2314
11th to 20thNight
55%6%6%15%13%4
2214
21st to endNight
55%7%8%14%13%5%
1776
March1st to 10thNight
49%49%13%19%6%
2080
11th to 20thNight
52%7%11%16%12%3
1980
21st to endNight
50%6%12%18%12%2
2178
April1st to 10thNight
41%6%12%21%17%2
1980
11th to 20thNight
40%8%8%20%19%5%
1737
21st to endNight
41%8%12%27%12%1
1620
May1st to 10thNight
44%10%14%22%9%2
1620
11th to 20thNight
44%13%15%19%8%1
1593
21st to endNight
41%12%15%23%8%1
1745
June1st to 10thNight
39%14%18%19%8%1
1620
11th to 20thNight
31%16%23%22%7%1
1620
21st to endNight
39%12%17%20%10%3
1620
July1st to 10thNight
43%15%17%16%9%
1575
11th to 20thNight
37%16%24%13%8%2
1566
21st to endNight
40%16%20%17%6%
1672
August1st to 10thNight
38%14%21%20%6%
1600
11th to 20thNight
43%15%16%16%9%1
1606
21st to endNight
42%12%19%17%8%1
1980
September1st to 10thNight
41%10%15%19%13%3
1974
11th to 20thNight
41%10%14%18%17%
1980
21st to endNight
38%8%11%21%19%3
1980
October1st to 10thNight
35%7%10%19%24%5%
1980
11th to 20thNight
39%6%9%22%18%6%
2137
21st to endNight
36%6%7%21%23%8%
2376
November1st to 10thNight
37%6%8%19%24%7%
2378
11th to 20thNight
39%6%7%19%22%8%
2470
21st to endNight
41%7%6%22%20%4
2470
December1st to 10thNight
55%8%8%14%12%4
2470
11th to 20thNight
47%9%7%13%20%4
3044
21st to endNight
52%9%10%16%11%2
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
25%33%30%10%1
270
11th to 20thDay
35%26%25%12%1
270
21st to endDay
25%33%31%10%2
297
February1st to 10thDay
26%28%34%10%2
270
11th to 20thDay
38%38%20%4
267
21st to endDay
39%32%22%7%
198
March1st to 10thDay
26%25%33%13%3
319
11th to 20thDay
27%26%30%12%41
420
21st to endDay
25%23%31%16%5%
462
April1st to 10thDay
22%22%27%20%8%1
420
11th to 20thDay
22%23%25%19%9%2
412
21st to endDay
26%15%27%19%9%3
420
May1st to 10thDay
20%21%33%14%8%4
423
11th to 20thDay
15%12%28%26%11%8%
447
21st to endDay
17%8%22%28%13%12%
485
June1st to 10thDay
11%10%24%28%19%7%
450
11th to 20thDay
8%7%22%28%24%11%
450
21st to endDay
14%6%26%29%15%11%
450
July1st to 10thDay
12%6%20%24%26%13%
445
11th to 20thDay
11%5%18%30%20%16%
444
21st to endDay
12%416%30%25%14%
488
August1st to 10thDay
17%8%15%25%22%13%
446
11th to 20thDay
11%7%18%30%25%9%
439
21st to endDay
16%213%26%31%12%
495
September1st to 10thDay
9%418%27%31%10%
450
11th to 20thDay
18%5%15%28%25%9%
450
21st to endDay
16%7%18%34%20%5%
450
October1st to 10thDay
17%9%23%26%18%7%
450
11th to 20thDay
17%14%29%26%12%3
450
21st to endDay
21%13%28%25%10%2
495
November1st to 10thDay
17%18%31%24%9%1
293
11th to 20thDay
19%24%35%18%4
270
21st to endDay
19%24%32%20%5%
270
December1st to 10thDay
27%25%32%14%1
270
11th to 20thDay
20%24%33%19%3
270
21st to endDay
24%24%37%11%3
297
January1st to 10thNight
23%22%29%22%4
760
11th to 20thNight
26%24%29%17%5%
760
21st to endNight
21%22%33%22%2
836
February1st to 10thNight
22%17%33%26%3
760
11th to 20thNight
27%23%33%16%1
742
21st to endNight
28%24%27%18%2
592
March1st to 10thNight
21%20%30%25%4
720
11th to 20thNight
23%20%28%22%7%1
720
21st to endNight
22%18%30%22%8%1
792
April1st to 10thNight
20%19%29%22%9%1
720
11th to 20thNight
20%13%29%25%12%1
533
21st to endNight
19%11%30%29%11%1
540
May1st to 10thNight
19%10%29%26%13%3
540
11th to 20thNight
15%8%23%32%19%2
531
21st to endNight
12%216%34%31%5%
584
June1st to 10thNight
9%5%16%36%29%5%
540
11th to 20thNight
5%416%34%31%10%
540
21st to endNight
9%316%32%33%7%
540
July1st to 10thNight
12%29%29%42%6%
525
11th to 20thNight
10%310%29%38%11%
522
21st to endNight
8%39%29%41%9%
591
August1st to 10thNight
9%5%7%32%39%8%
537
11th to 20thNight
11%311%34%37%5%
534
21st to endNight
12%38%30%37%9%
594
September1st to 10thNight
12%5%9%30%38%7%
714
11th to 20thNight
17%411%32%30%7%
720
21st to endNight
16%417%33%28%2
720
October1st to 10thNight
18%6%19%21%28%8%
720
11th to 20thNight
18%10%26%28%16%2
720
21st to endNight
17%12%25%30%14%3
792
November1st to 10thNight
18%9%19%33%16%4
740
11th to 20thNight
17%15%25%29%11%2
760
21st to endNight
19%14%27%28%12%1
760
December1st to 10thNight
22%21%26%24%6%
760
11th to 20thNight
19%19%29%26%6%1
760
21st to endNight
22%18%30%25%4
836
Page generated at 2024-02-17 06:28:35. Version ac07

Copyright 2024 Attilla Danko


Great Smokey Mountains National Park Clear Sky Chart |Charts Home