East Kentucky Science Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the East Kentucky Science Center clear sky chart from 2005-11-05 to 2017-03-22.

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
42%
14985
19%
45246
14%
14943
48%
14943
23%
30036

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
20%
720
15%
2327
8%
716
29%
716
13%
1741
January16th to endNight
20%
768
17%
2496
9%
768
31%
768
15%
1782
February1st to 15thNight
21%
703
13%
2208
5%
701
31%
701
16%
1554
February16th to endNight
18%
631
14%
1893
7%
631
25%
631
14%
1416
March1st to 15thNight
28%
720
17%
2031
11%
720
33%
720
18%
1473
March16th to endNight
32%
732
14%
2013
9%
732
36%
732
20%
1437
April1st to 15thNight
31%
618
21%
1757
10%
618
41%
618
24%
1148
April16th to endNight
40%
495
21%
1485
12%
495
48%
495
26%
973
May1st to 15thNight
41%
495
15%
1485
8%
495
47%
495
22%
1017
May16th to endNight
58%
513
18%
1540
15%
513
60%
513
31%
967
June1st to 15thNight
65%
495
17%
1485
15%
495
67%
495
32%
907
June16th to endNight
64%
495
16%
1485
14%
495
66%
495
34%
888
July1st to 15thNight
61%
465
14%
1395
12%
465
63%
465
28%
893
July16th to endNight
70%
522
15%
1469
14%
489
73%
489
31%
907
August1st to 15thNight
74%
494
24%
1474
21%
491
75%
491
34%
882
August16th to endNight
72%
530
23%
1629
22%
530
73%
530
34%
957
September1st to 15thNight
64%
660
25%
1815
20%
660
66%
660
32%
1142
September16th to endNight
57%
657
25%
1815
20%
657
60%
657
31%
1149
October1st to 15thNight
54%
660
30%
1892
26%
660
58%
660
35%
1130
October16th to endNight
40%
704
25%
2112
19%
704
49%
704
27%
1342
November1st to 15thNight
48%
700
28%
2264
23%
700
57%
700
30%
1318
November16th to endNight
37%
720
22%
2340
16%
720
47%
720
23%
1483
December1st to 15thNight
28%
720
14%
2340
10%
720
33%
720
14%
1707
December16th to endNight
26%
768
17%
2496
9%
768
35%
768
14%
1823

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%35%45%7%35%
45627
Night
15%7%35%42445%7%39%
45439
Cloud CoverDay
15%7%36%5%35%45%7%36%
45637
Night
15%7%35%42445%7%39%
45443
TransparencyDay
46%5%11%20%13%2
45338
Night
44%411%21%14%3
45246
SeeingDay
19%8%20%21%19%10%
4700
Night
20%8%22%27%18%2
14988

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
20%13%5%8%6%3424426%
1611
16th to endDay
18%13%46%5%33436%31%
1728
February1st to 15thDay
17%13%5%8%5%24345%29%
1651
16th to endDay
19%11%46%5%34446%27%
1580
March1st to 15thDay
22%10%35%42344434%
1918
16th to endDay
20%8%36%5%25%445%33%
2008
April1st to 15thDay
15%6%35%424347%41%
1869
16th to endDay
15%6%27%5%24446%40%
2145
May1st to 15thDay
16%8%37%7%45%5%5%7%27%
2136
16th to endDay
9%6%36%5%36%6%6%7%37%
2223
June1st to 15thDay
9%426%7%46%6%6%7%37%
2145
16th to endDay
8%436%6%36%6%8%9%36%
2145
July1st to 15thDay
13%6%36%5%36%6%7%9%33%
2145
16th to endDay
10%6%36%6%47%6%8%10%29%
2283
August1st to 15thDay
10%5%27%6%46%7%7%10%32%
2145
16th to endDay
10%5%25%6%46%5%6%9%37%
2208
September1st to 15thDay
13%5%245%35%46%8%39%
1815
16th to endDay
17%5%245%2343444%
1815
October1st to 15thDay
13%5%24323346%49%
1736
16th to endDay
20%6%25%312236%44%
1760
November1st to 15thDay
13%6%24423445%47%
1593
16th to endDay
16%9%35%423345%41%
1620
December1st to 15thDay
24%10%36%43434430%
1620
16th to endDay
21%13%36%5%24436%28%
1728
January1st to 15thNight
20%11%48%5%25%34427%
2327
16th to endNight
19%12%5%7%423435%31%
2496
February1st to 15thNight
17%10%46%6%23346%32%
2206
16th to endNight
19%12%47%5%34445%27%
1893
March1st to 15thNight
19%8%36%5%3444434%
2019
16th to endNight
16%8%46%5%4445%7%33%
2013
April1st to 15thNight
15%7%345%2335%7%41%
1757
16th to endNight
12%6%345%34448%41%
1485
May1st to 15thNight
16%7%35%425%5%5%8%35%
1485
16th to endNight
8%5%25%5%245%6%8%43%
1538
June1st to 15thNight
8%323435%6%8%10%43%
1485
16th to endNight
7%424425%6%6%11%45%
1485
July1st to 15thNight
10%5%25%435%47%10%39%
1485
16th to endNight
6%416%436%6%7%9%42%
1577
August1st to 15thNight
6%423436%48%10%45%
1485
16th to endNight
8%4233346%7%10%45%
1629
September1st to 15thNight
11%41443445%9%46%
1815
16th to endNight
11%5%25%5%23445%48%
1815
October1st to 15thNight
12%5%14423446%51%
1892
16th to endNight
18%7%2442343445%
2112
November1st to 15thNight
15%5%23313336%51%
2264
16th to endNight
15%8%34424346%41%
2340
December1st to 15thNight
21%11%46%5%3435%5%28%
2340
16th to endNight
21%12%45%5%24345%29%
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
20%12%5%8%6%3434426%
1611
16th to endDay
18%13%45%5%33435%31%
1728
February1st to 15thDay
18%13%48%5%34345%29%
1651
16th to endDay
19%11%46%5%34446%28%
1580
March1st to 15thDay
21%9%45%323445%34%
1929
16th to endDay
20%8%35%5%25%445%33%
2007
April1st to 15thDay
15%6%345%24347%41%
1869
16th to endDay
15%6%26%5%24446%40%
2145
May1st to 15thDay
16%7%28%7%45%6%5%7%27%
2136
16th to endDay
10%5%36%6%35%6%6%7%37%
2223
June1st to 15thDay
9%426%6%46%6%6%7%37%
2145
16th to endDay
8%436%6%46%6%8%8%37%
2145
July1st to 15thDay
13%6%35%6%25%6%6%9%33%
2145
16th to endDay
9%6%36%7%47%7%7%10%29%
2283
August1st to 15thDay
10%5%27%6%45%7%7%9%33%
2145
16th to endDay
10%5%15%6%5%6%5%6%9%37%
2208
September1st to 15thDay
13%6%25%435%5%6%8%39%
1815
16th to endDay
17%5%3442344444%
1815
October1st to 15thDay
13%5%24323347%49%
1736
16th to endDay
20%5%25%322236%45%
1760
November1st to 15thDay
13%6%2442444448%
1593
16th to endDay
16%9%35%423346%40%
1620
December1st to 15thDay
24%9%36%434345%30%
1620
16th to endDay
21%12%46%5%24336%28%
1728
January1st to 15thNight
20%11%5%8%5%25%33428%
2327
16th to endNight
19%12%5%7%423435%31%
2496
February1st to 15thNight
17%10%47%6%23346%32%
2199
16th to endNight
19%11%47%5%35%345%27%
1893
March1st to 15thNight
19%8%36%6%3443434%
2031
16th to endNight
16%8%37%5%3445%7%33%
2013
April1st to 15thNight
16%6%345%2335%7%41%
1757
16th to endNight
13%6%25%444448%41%
1485
May1st to 15thNight
16%7%35%425%45%8%35%
1484
16th to endNight
9%4245%25%5%6%8%44%
1538
June1st to 15thNight
8%323435%6%8%10%43%
1485
16th to endNight
7%423435%6%6%10%45%
1485
July1st to 15thNight
10%5%25%4345%7%9%40%
1485
16th to endNight
6%325%5%26%6%7%10%42%
1577
August1st to 15thNight
6%323435%5%7%10%45%
1485
16th to endNight
8%3234247%7%10%45%
1629
September1st to 15thNight
11%31443435%9%46%
1815
16th to endNight
11%5%25%5%24436%47%
1815
October1st to 15thNight
12%5%14423436%51%
1892
16th to endNight
18%6%24423335%44%
2112
November1st to 15thNight
16%5%23313246%51%
2264
16th to endNight
15%9%24434346%42%
2340
December1st to 15thNight
22%11%46%434445%29%
2340
16th to endNight
22%11%46%5%34345%29%
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
61%29%15%9%
1612
16th to endDay
55%29%23%7%1
1728
February1st to 15thDay
57%38%21%8%1
1653
16th to endDay
56%410%18%8%
1580
March1st to 15thDay
52%310%20%11%2
1929
16th to endDay
51%49%22%10%
2008
April1st to 15thDay
43%310%23%15%4
1869
16th to endDay
45%38%22%14%6%
2145
May1st to 15thDay
53%6%12%17%7%1
2136
16th to endDay
41%6%14%23%10%2
2227
June1st to 15thDay
42%8%13%22%13%
2145
16th to endDay
40%9%14%17%16%2
2145
July1st to 15thDay
44%8%14%16%14%1
2006
16th to endDay
43%9%14%21%8%2
2128
August1st to 15thDay
42%9%15%20%12%1
2132
16th to endDay
40%7%13%21%14%2
2208
September1st to 15thDay
40%5%11%20%16%4
1815
16th to endDay
43%38%20%22%1
1815
October1st to 15thDay
35%5%11%25%18%4
1736
16th to endDay
42%29%26%16%3
1760
November1st to 15thDay
38%37%21%24%4
1593
16th to endDay
45%36%24%19%
1620
December1st to 15thDay
56%39%18%9%2
1620
16th to endDay
58%311%19%7%
1728
January1st to 15thNight
59%38%14%12%2
2327
16th to endNight
55%28%21%9%1
2496
February1st to 15thNight
53%310%20%10%
2208
16th to endNight
57%410%17%8%1
1893
March1st to 15thNight
53%49%18%12%2
2031
16th to endNight
50%410%21%11%
2013
April1st to 15thNight
42%48%21%18%4
1757
16th to endNight
42%5%9%21%14%7%
1485
May1st to 15thNight
46%6%14%19%11%2
1485
16th to endNight
35%7%15%23%15%2
1540
June1st to 15thNight
31%9%18%22%15%1
1485
16th to endNight
31%7%17%22%15%4
1485
July1st to 15thNight
39%6%14%19%15%4
1395
16th to endNight
32%9%19%23%11%2
1469
August1st to 15thNight
31%7%14%26%18%2
1474
16th to endNight
30%7%13%24%19%3
1629
September1st to 15thNight
35%7%11%21%16%8%
1815
16th to endNight
37%5%9%19%26%1
1815
October1st to 15thNight
34%310%27%18%6%
1892
16th to endNight
42%27%24%19%3
2112
November1st to 15thNight
35%36%22%24%7%
2264
16th to endNight
43%38%25%16%2
2340
December1st to 15thNight
57%39%18%8%2
2340
16th to endNight
56%49%19%8%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
36%22%27%8%22
90
16th to endDay
35%26%22%14%1
96
February1st to 15thDay
30%22%36%6%4
90
16th to endDay
32%13%38%14%1
81
March1st to 15thDay
30%11%29%22%5%
219
16th to endDay
20%14%31%19%11%2
250
April1st to 15thDay
22%14%25%20%14%1
210
16th to endDay
19%7%25%24%16%7%
210
May1st to 15thDay
20%9%28%17%14%8%
228
16th to endDay
15%417%23%22%16%
267
June1st to 15thDay
9%5%15%28%30%10%
255
16th to endDay
10%421%25%20%16%
255
July1st to 15thDay
24%419%23%11%17%
245
16th to endDay
12%211%23%28%22%
270
August1st to 15thDay
12%39%21%31%21%
253
16th to endDay
12%10%22%34%19%
268
September1st to 15thDay
16%8%21%34%19%
255
16th to endDay
22%311%25%24%12%
254
October1st to 15thDay
17%6%21%20%24%9%
255
16th to endDay
21%10%23%24%17%2
272
November1st to 15thDay
21%7%23%21%21%2
101
16th to endDay
26%18%21%22%10%1
90
December1st to 15thDay
26%20%30%12%8%2
90
16th to endDay
30%22%27%17%11
96
January1st to 15thNight
30%14%28%20%5%
720
16th to endNight
27%15%32%22%2
768
February1st to 15thNight
26%13%32%26%
704
16th to endNight
29%17%31%19%1
631
March1st to 15thNight
28%12%26%26%6%
720
16th to endNight
20%13%28%26%11%
732
April1st to 15thNight
20%14%29%24%9%
618
16th to endNight
17%8%29%29%14%1
495
May1st to 15thNight
19%7%25%31%14%1
495
16th to endNight
12%316%31%29%7%
515
June1st to 15thNight
10%115%35%31%4
495
16th to endNight
9%116%35%31%4
495
July1st to 15thNight
14%213%34%30%4
465
16th to endNight
8%29%28%41%9%
522
August1st to 15thNight
8%17%33%42%6%
494
16th to endNight
10%16%30%42%8%
530
September1st to 15thNight
13%111%26%40%5%
660
16th to endNight
14%415%27%35%3
657
October1st to 15thNight
15%6%18%28%25%5%
660
16th to endNight
22%7%24%27%16%1
704
November1st to 15thNight
18%8%21%30%18%2
700
16th to endNight
20%13%23%29%12%
720
December1st to 15thNight
30%12%22%26%7%
720
16th to endNight
31%11%26%27%4
768
Page generated at 2017-03-23 07:36:11. Version ac04

Copyright 2017 A. Danko


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