Morehead State University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Morehead State University clear sky chart from 2005-11-05 to 2017-09-22.

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
40%
15512
19%
46984
13%
15468
47%
15468
23%
31169

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
15%
720
14%
2327
6%
716
24%
716
11%
1770
January16th to endNight
18%
768
16%
2496
7%
768
29%
768
13%
1806
February1st to 15thNight
19%
704
13%
2190
5%
701
28%
701
15%
1580
February16th to endNight
14%
631
13%
1893
4%
631
23%
631
13%
1430
March1st to 15thNight
23%
720
18%
2055
9%
720
30%
720
16%
1461
March16th to endNight
30%
768
15%
2112
8%
768
36%
768
20%
1494
April1st to 15thNight
31%
635
20%
1893
10%
635
41%
635
26%
1204
April16th to endNight
36%
540
21%
1623
10%
540
46%
540
25%
1073
May1st to 15thNight
37%
540
15%
1620
9%
540
43%
540
20%
1126
May16th to endNight
56%
562
19%
1684
14%
561
59%
561
28%
1075
June1st to 15thNight
64%
540
19%
1620
16%
540
67%
540
34%
956
June16th to endNight
62%
540
17%
1620
15%
540
65%
540
34%
970
July1st to 15thNight
56%
510
14%
1530
12%
510
58%
510
28%
986
July16th to endNight
72%
564
19%
1595
17%
531
74%
531
34%
960
August1st to 15thNight
69%
539
22%
1609
19%
536
72%
536
35%
956
August16th to endNight
71%
573
24%
1800
24%
573
72%
573
35%
1036
September1st to 15thNight
62%
701
24%
1961
19%
701
65%
701
33%
1205
September16th to endNight
57%
685
27%
1892
20%
685
60%
685
32%
1188
October1st to 15thNight
53%
660
31%
1875
25%
660
59%
660
36%
1102
October16th to endNight
37%
704
24%
2137
18%
704
47%
704
25%
1356
November1st to 15thNight
45%
700
27%
2276
23%
700
55%
700
29%
1329
November16th to endNight
30%
720
21%
2340
14%
720
41%
720
21%
1529
December1st to 15thNight
25%
720
13%
2340
8%
720
31%
720
13%
1715
December16th to endNight
21%
768
14%
2496
6%
768
31%
768
12%
1862

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
15%7%36%5%3445%7%36%
47890
Night
14%7%35%42445%7%39%
47177
Cloud CoverDay
15%7%36%5%3445%7%36%
47900
Night
14%7%35%42445%7%39%
47181
TransparencyDay
47%5%10%20%13%2
47601
Night
44%5%10%21%15%3
46984
SeeingDay
20%9%23%21%15%9%
5365
Night
19%9%24%26%16%2
15513

By Month

Percentage Cloud Cover NE (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%12%6%10%5%3434426%
1611
16th to endDay
19%13%6%7%433336%29%
1728
February1st to 15thDay
18%11%410%5%23436%28%
1671
16th to endDay
17%12%47%5%25%446%29%
1580
March1st to 15thDay
23%9%36%324345%33%
1893
16th to endDay
20%8%36%435%35%5%33%
2112
April1st to 15thDay
17%6%35%5%33346%39%
2065
16th to endDay
17%6%25%434447%38%
2337
May1st to 15thDay
21%7%26%5%35%5%5%6%30%
2331
16th to endDay
11%5%35%7%36%6%5%8%35%
2431
June1st to 15thDay
9%5%25%5%45%5%6%8%40%
2340
16th to endDay
9%426%6%45%5%6%8%38%
2340
July1st to 15thDay
15%7%25%5%35%5%6%10%32%
2340
16th to endDay
11%5%346%5%7%7%7%9%32%
2465
August1st to 15thDay
9%5%246%46%6%7%9%36%
2340
16th to endDay
9%425%6%25%6%7%10%40%
2399
September1st to 15thDay
13%435%43445%7%42%
1986
16th to endDay
16%5%34423346%44%
1881
October1st to 15thDay
13%5%25%32335%6%49%
1755
16th to endDay
21%7%23212345%45%
1735
November1st to 15thDay
13%6%24434335%48%
1582
16th to endDay
17%9%25%434335%39%
1620
December1st to 15thDay
25%12%46%31424428%
1620
16th to endDay
21%13%46%423345%28%
1728
January1st to 15thNight
20%11%5%10%5%3344425%
2327
16th to endNight
19%11%47%5%2434430%
2496
February1st to 15thNight
19%11%5%6%424445%31%
2188
16th to endNight
18%13%48%5%35%445%27%
1893
March1st to 15thNight
17%9%36%5%33345%34%
2043
16th to endNight
15%9%36%6%3435%7%34%
2112
April1st to 15thNight
15%6%2432446%7%42%
1893
16th to endNight
16%5%24424447%41%
1623
May1st to 15thNight
18%5%35%5%345%6%7%33%
1620
16th to endNight
11%4145%35%46%10%42%
1682
June1st to 15thNight
6%324335%5%7%9%47%
1620
16th to endNight
7%3235%15%5%8%11%45%
1620
July1st to 15thNight
11%5%25%435%45%8%42%
1620
16th to endNight
6%3144445%7%11%44%
1703
August1st to 15thNight
6%3145%345%7%10%47%
1620
16th to endNight
6%325%4145%5%9%49%
1800
September1st to 15thNight
11%5%23434448%46%
1961
16th to endNight
10%5%25%5%23346%48%
1892
October1st to 15thNight
11%42442335%7%51%
1875
16th to endNight
18%5%25%423336%44%
2137
November1st to 15thNight
13%6%33323246%50%
2276
16th to endNight
18%9%35%423346%39%
2340
December1st to 15thNight
22%11%47%424345%29%
2340
16th to endNight
20%13%5%6%424346%26%
2496

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%12%6%10%6%2334426%
1611
16th to endDay
18%13%5%7%423336%29%
1728
February1st to 15thDay
18%11%411%5%33336%28%
1671
16th to endDay
17%12%47%5%35%446%29%
1580
March1st to 15thDay
23%9%36%324345%32%
1904
16th to endDay
19%8%36%5%34346%33%
2111
April1st to 15thDay
17%6%35%5%33346%39%
2065
16th to endDay
17%6%25%424447%38%
2337
May1st to 15thDay
20%7%36%6%345%5%6%29%
2331
16th to endDay
11%5%25%7%46%6%6%8%35%
2431
June1st to 15thDay
9%5%25%5%46%5%6%8%40%
2340
16th to endDay
9%436%6%45%5%5%9%38%
2340
July1st to 15thDay
14%7%25%5%35%5%6%10%32%
2340
16th to endDay
10%6%247%47%7%7%9%32%
2465
August1st to 15thDay
9%5%25%6%46%6%7%9%36%
2340
16th to endDay
9%5%25%6%25%6%7%10%39%
2399
September1st to 15thDay
13%5%35%43446%7%42%
1986
16th to endDay
16%434423346%44%
1881
October1st to 15thDay
12%5%15%42335%6%49%
1755
16th to endDay
21%7%23212235%44%
1735
November1st to 15thDay
13%7%23434235%48%
1582
16th to endDay
16%9%35%434345%39%
1620
December1st to 15thDay
24%12%46%31435%428%
1620
16th to endDay
21%13%46%423345%28%
1728
January1st to 15thNight
19%11%5%10%5%33445%25%
2327
16th to endNight
18%11%5%7%5%3434430%
2496
February1st to 15thNight
18%11%5%6%424435%31%
2181
16th to endNight
18%13%48%5%35%445%27%
1893
March1st to 15thNight
17%9%36%5%33445%34%
2055
16th to endNight
15%9%36%6%3435%7%34%
2112
April1st to 15thNight
15%7%2442445%7%42%
1893
16th to endNight
16%5%25%424447%41%
1623
May1st to 15thNight
18%5%35%5%345%6%7%33%
1619
16th to endNight
11%5%24435%46%10%42%
1682
June1st to 15thNight
6%324335%5%7%10%47%
1620
16th to endNight
8%3235%245%7%12%45%
1620
July1st to 15thNight
11%5%25%425%5%5%8%43%
1620
16th to endNight
6%4144445%8%11%44%
1703
August1st to 15thNight
6%31443447%10%48%
1620
16th to endNight
6%415%4145%6%10%49%
1800
September1st to 15thNight
11%5%23435%45%8%46%
1961
16th to endNight
10%5%25%5%23347%48%
1892
October1st to 15thNight
11%42442335%7%51%
1875
16th to endNight
18%5%15%423336%44%
2137
November1st to 15thNight
13%6%33323246%50%
2276
16th to endNight
18%9%35%423346%39%
2340
December1st to 15thNight
22%10%47%424345%29%
2340
16th to endNight
20%13%5%7%434346%26%
2496

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
62%37%16%8%
1612
16th to endDay
57%39%21%6%1
1728
February1st to 15thDay
58%38%20%7%1
1673
16th to endDay
56%410%19%8%
1580
March1st to 15thDay
54%39%20%10%1
1904
16th to endDay
52%49%22%9%1
2112
April1st to 15thDay
46%47%22%14%3
2065
16th to endDay
45%5%9%20%14%5%
2337
May1st to 15thDay
53%5%11%17%9%1
2331
16th to endDay
44%8%11%21%11%1
2435
June1st to 15thDay
39%8%11%22%15%1
2340
16th to endDay
42%7%11%17%17%2
2340
July1st to 15thDay
46%7%12%15%14%2
2201
16th to endDay
43%8%12%20%12%2
2310
August1st to 15thDay
41%8%13%20%14%1
2327
16th to endDay
38%7%12%24%14%3
2399
September1st to 15thDay
40%5%11%19%17%5%
1986
16th to endDay
41%38%21%23%2
1881
October1st to 15thDay
35%5%9%25%20%3
1755
16th to endDay
42%210%26%16%1
1735
November1st to 15thDay
40%37%23%21%4
1582
16th to endDay
47%38%20%18%1
1620
December1st to 15thDay
58%310%17%8%1
1620
16th to endDay
58%311%18%6%
1728
January1st to 15thNight
61%37%13%11%1
2327
16th to endNight
56%38%21%8%1
2496
February1st to 15thNight
55%39%19%10%1
2190
16th to endNight
59%310%17%9%
1893
March1st to 15thNight
51%48%20%12%1
2055
16th to endNight
49%5%10%22%11%
2112
April1st to 15thNight
39%410%21%21%3
1893
16th to endNight
41%5%9%21%14%6%
1623
May1st to 15thNight
47%7%12%19%9%3
1620
16th to endNight
36%8%13%22%16%2
1684
June1st to 15thNight
30%7%14%26%17%3
1620
16th to endNight
30%9%15%24%16%4
1620
July1st to 15thNight
39%6%12%20%16%4
1530
16th to endNight
30%8%16%26%15%3
1595
August1st to 15thNight
30%7%16%24%18%2
1609
16th to endNight
29%7%11%27%18%4
1800
September1st to 15thNight
35%5%12%19%18%7%
1961
16th to endNight
36%48%20%27%1
1892
October1st to 15thNight
32%49%28%19%5%
1875
16th to endNight
42%38%22%19%3
2137
November1st to 15thNight
36%27%22%24%6%
2276
16th to endNight
46%39%22%16%1
2340
December1st to 15thNight
57%49%17%8%1
2340
16th to endNight
59%310%17%7%1
2496

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
34%24%28%8%12
90
16th to endDay
42%29%19%8%
96
February1st to 15thDay
26%36%25%7%3
90
16th to endDay
30%13%43%12%
81
March1st to 15thDay
34%13%33%15%3
194
16th to endDay
23%15%33%18%8%1
288
April1st to 15thDay
23%12%28%24%8%1
270
16th to endDay
19%12%30%21%9%6%
270
May1st to 15thDay
30%9%29%14%9%6%
288
16th to endDay
17%6%28%19%16%11%
331
June1st to 15thDay
11%5%17%36%16%11%
315
16th to endDay
13%8%26%23%16%12%
315
July1st to 15thDay
23%419%23%13%15%
305
16th to endDay
10%215%25%21%24%
326
August1st to 15thDay
14%112%25%28%17%
313
16th to endDay
13%15%28%22%18%
332
September1st to 15thDay
15%5%13%21%29%14%
315
16th to endDay
20%215%17%30%13%
278
October1st to 15thDay
16%5%22%24%21%8%
255
16th to endDay
20%10%28%25%14%1
247
November1st to 15thDay
22%7%30%22%16%1
90
16th to endDay
32%17%27%15%5%1
90
December1st to 15thDay
36%18%27%11%41
90
16th to endDay
33%28%31%6%1
96
January1st to 15thNight
29%17%32%17%3
720
16th to endNight
25%19%32%20%1
768
February1st to 15thNight
28%14%34%21%1
704
16th to endNight
27%18%36%16%1
631
March1st to 15thNight
25%14%30%22%5%
720
16th to endNight
20%12%29%26%9%
768
April1st to 15thNight
22%12%30%23%9%
635
16th to endNight
20%7%31%26%12%1
540
May1st to 15thNight
22%6%26%29%12%2
540
16th to endNight
13%219%31%27%4
563
June1st to 15thNight
7%119%42%25%3
540
16th to endNight
9%20%37%28%3
540
July1st to 15thNight
15%116%31%30%4
510
16th to endNight
9%9%33%38%8%
564
August1st to 15thNight
10%9%34%39%6%
539
16th to endNight
8%10%35%36%8%
573
September1st to 15thNight
14%214%29%33%6%
701
16th to endNight
14%316%27%32%5%
685
October1st to 15thNight
13%6%22%28%23%5%
660
16th to endNight
21%9%27%24%14%2
704
November1st to 15thNight
18%8%24%27%19%2
700
16th to endNight
23%15%26%24%8%1
720
December1st to 15thNight
30%13%24%25%5%
720
16th to endNight
29%15%30%20%3
768
Page generated at 2017-09-23 06:43:43. Version ac04

Copyright 2017 A. Danko


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