Kansas State University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kansas State University clear sky chart from 2005-11-06 to 2024-01-14.

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
41%
24512
24%
74563
14%
24450
51%
24450
32%
43913

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
33%
950
24%
2458
9%
946
45%
946
32%
1562
January11th to 20thNight
31%
918
24%
2386
9%
918
41%
918
32%
1529
January21st to endNight
31%
990
24%
2574
10%
990
40%
990
32%
1644
February1st to 10thNight
27%
900
18%
2340
6%
900
34%
900
27%
1585
February11th to 20thNight
28%
795
20%
2190
6%
791
37%
791
26%
1421
February21st to endNight
27%
592
27%
1776
9%
592
42%
592
29%
1057
March1st to 10thNight
28%
571
25%
2011
11%
571
44%
571
28%
1120
March11th to 20thNight
32%
540
21%
1980
14%
540
42%
540
22%
1175
March21st to endNight
25%
594
16%
2178
9%
594
36%
594
17%
1434
April1st to 10thNight
28%
540
20%
1968
12%
540
43%
540
28%
1046
April11th to 20thNight
30%
533
23%
1682
13%
533
44%
533
25%
1017
April21st to endNight
31%
540
22%
1620
13%
540
46%
540
26%
1019
May1st to 10thNight
34%
540
16%
1620
12%
540
42%
540
23%
1068
May11th to 20thNight
40%
531
21%
1594
16%
531
48%
531
30%
977
May21st to endNight
45%
582
15%
1745
10%
582
52%
582
29%
1099
June1st to 10thNight
62%
540
23%
1620
16%
540
67%
540
41%
873
June11th to 20thNight
54%
540
20%
1620
12%
540
60%
540
40%
881
June21st to endNight
55%
540
23%
1620
13%
540
62%
540
45%
842
July1st to 10thNight
67%
525
17%
1575
14%
525
69%
525
40%
863
July11th to 20thNight
70%
522
25%
1566
22%
522
73%
522
53%
760
July21st to endNight
67%
591
25%
1673
24%
558
71%
558
41%
912
August1st to 10thNight
67%
537
22%
1601
22%
534
72%
534
41%
865
August11th to 20thNight
69%
534
29%
1600
31%
534
74%
534
42%
869
August21st to endNight
71%
594
30%
1829
32%
594
74%
594
44%
943
September1st to 10thNight
60%
540
26%
1930
26%
540
67%
540
37%
975
September11th to 20thNight
54%
540
28%
1980
26%
540
64%
540
34%
1033
September21st to endNight
56%
540
31%
1980
25%
540
68%
540
37%
978
October1st to 10thNight
47%
628
27%
2068
21%
628
54%
628
32%
1164
October11th to 20thNight
35%
720
30%
2160
15%
720
48%
720
38%
1181
October21st to endNight
36%
792
28%
2376
14%
792
46%
792
33%
1352
November1st to 10thNight
43%
871
31%
2351
14%
871
55%
871
44%
1279
November11th to 20thNight
34%
950
30%
2470
10%
950
48%
950
41%
1421
November21st to endNight
37%
950
27%
2470
11%
950
47%
950
36%
1491
December1st to 10thNight
37%
950
23%
2602
9%
950
48%
950
33%
1577
December11th to 20thNight
30%
949
27%
2876
9%
948
42%
948
27%
1745
December21st to endNight
28%
1043
17%
4474
11%
1026
41%
1026
16%
3156

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
11%6%35%43445%7%48%
74762
Night
10%6%25%43445%7%51%
74987
TransparencyDay
36%6%12%26%17%3
74486
Night
33%5%12%27%19%4
74783
SeeingDay
13%10%30%29%15%3
14505
Night
13%9%33%34%11%1
24517

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
10%7%36%43445%8%46%
1707
11th to 20thDay
10%8%46%42445%6%47%
1647
21st to endDay
9%7%5%7%5%3445%6%43%
1782
February1st to 10thDay
12%11%47%5%33446%42%
1620
11th to 20thDay
9%8%46%435%5%6%7%43%
1672
21st to endDay
9%8%37%5%3445%8%45%
1480
March1st to 10thDay
10%8%35%4345%47%47%
1948
11th to 20thDay
20%9%34323446%42%
1980
21st to endDay
16%10%37%5%345%5%6%35%
2178
April1st to 10thDay
13%6%25%42345%7%48%
1990
11th to 20thDay
13%7%26%4445%5%6%43%
2226
21st to endDay
18%6%35%5%35%5%46%41%
2340
May1st to 10thDay
15%8%36%5%345%5%7%39%
2340
11th to 20thDay
15%6%35%5%35%5%6%6%42%
2302
21st to endDay
15%7%36%5%45%5%7%8%36%
2531
June1st to 10thDay
6%42443445%9%55%
2340
11th to 20thDay
7%4245%345%5%9%51%
2340
21st to endDay
6%324435%5%7%9%53%
2340
July1st to 10thDay
8%425%5%35%5%6%9%46%
2340
11th to 20thDay
4225%5%35%5%7%9%54%
2340
21st to endDay
7%425%5%36%6%6%9%48%
2546
August1st to 10thDay
7%4245%35%6%6%10%48%
2328
11th to 20thDay
7%42443345%8%54%
2301
21st to endDay
8%32442445%7%58%
2525
September1st to 10thDay
12%32442345%6%55%
2027
11th to 20thDay
10%5%245%3445%6%52%
1980
21st to endDay
9%5%23433446%56%
1980
October1st to 10thDay
12%5%2442335%6%54%
1873
11th to 20thDay
11%5%23323335%60%
1800
21st to endDay
13%6%24433345%53%
1980
November1st to 10thDay
7%42333435%7%59%
1724
11th to 20thDay
10%5%24423346%56%
1710
21st to endDay
13%6%24324346%53%
1710
December1st to 10thDay
9%5%35%5%25%46%8%48%
1558
11th to 20thDay
9%8%38%6%34437%45%
2142
21st to endDay
14%11%6%14%6%335%46%28%
3135
January1st to 10thNight
8%7%36%5%3445%6%50%
2458
11th to 20thNight
9%8%36%42445%6%47%
2386
21st to endNight
9%8%25%5%35%45%6%48%
2574
February1st to 10thNight
10%10%46%6%3445%7%43%
2340
11th to 20thNight
10%6%37%5%35%5%6%7%44%
2189
21st to endNight
9%7%35%5%345%5%6%51%
1776
March1st to 10thNight
10%7%26%3335%46%51%
2011
11th to 20thNight
14%6%25%5%3445%5%47%
1980
21st to endNight
18%8%46%5%3445%6%37%
2178
April1st to 10thNight
11%425%423447%53%
1968
11th to 20thNight
13%8%25%43445%7%46%
1682
21st to endNight
15%5%25%42445%7%46%
1620
May1st to 10thNight
17%6%35%435%5%5%8%40%
1620
11th to 20thNight
14%5%25%4345%46%48%
1593
21st to endNight
11%5%345%345%5%9%46%
1745
June1st to 10thNight
5%213335%46%10%57%
1620
11th to 20thNight
6%4134246%6%10%55%
1620
21st to endNight
6%21342447%9%59%
1620
July1st to 10thNight
6%324435%5%6%8%54%
1620
11th to 20thNight
231232446%10%63%
1620
21st to endNight
6%425%4245%6%10%52%
1772
August1st to 10thNight
33144345%7%10%54%
1611
11th to 20thNight
5%424434448%58%
1600
21st to endNight
5%31433445%7%61%
1829
September1st to 10thNight
9%324333446%59%
1930
11th to 20thNight
10%32443345%6%56%
1980
21st to endNight
8%32442345%6%61%
1980
October1st to 10thNight
12%42432445%6%53%
2068
11th to 20thNight
13%423322246%59%
2160
21st to endNight
13%5%25%423345%55%
2376
November1st to 10thNight
7%5%24323345%63%
2351
11th to 20thNight
8%42442345%6%58%
2470
21st to endNight
11%6%24323345%56%
2470
December1st to 10thNight
8%6%35%425%5%5%7%51%
2602
11th to 20thNight
10%8%35%42445%7%49%
3036
21st to endNight
17%12%6%8%42333436%
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
38%5%13%28%15%2
1708
11th to 20thDay
38%5%15%26%14%1
1647
21st to endDay
41%5%15%26%12%1
1782
February1st to 10thDay
44%5%15%22%10%4
1620
11th to 20thDay
40%5%13%26%13%4
1681
21st to endDay
38%5%10%25%19%4
1480
March1st to 10thDay
37%412%23%19%4
1948
11th to 20thDay
44%49%22%17%3
1980
21st to endDay
49%6%13%21%9%2
2178
April1st to 10thDay
37%413%24%19%4
1990
11th to 20thDay
40%6%12%23%16%2
2226
21st to endDay
44%6%10%26%13%
2340
May1st to 10thDay
46%7%11%20%14%2
2340
11th to 20thDay
41%6%13%26%13%
2306
21st to endDay
44%9%14%21%9%2
2531
June1st to 10thDay
26%7%15%34%15%2
2340
11th to 20thDay
29%7%13%28%21%3
2340
21st to endDay
26%7%14%30%19%4
2340
July1st to 10thDay
32%7%14%26%18%3
2276
11th to 20thDay
24%7%14%28%20%6%
2271
21st to endDay
29%7%14%32%17%2
2405
August1st to 10thDay
29%10%16%27%16%2
2314
11th to 20thDay
28%6%12%31%20%3
2301
21st to endDay
25%7%11%26%23%8%
2525
September1st to 10thDay
29%6%12%27%19%7%
2027
11th to 20thDay
32%6%10%26%23%3
1980
21st to endDay
29%6%9%28%25%3
1980
October1st to 10thDay
32%5%10%27%24%3
1873
11th to 20thDay
28%46%28%27%7%
1800
21st to endDay
35%310%24%21%7%
1980
November1st to 10thDay
26%5%13%29%22%6%
1724
11th to 20thDay
30%410%26%26%4
1710
21st to endDay
34%410%29%21%2
1710
December1st to 10thDay
35%5%12%31%16%1
1558
11th to 20thDay
41%412%27%15%1
2140
21st to endDay
59%49%18%9%1
3135
January1st to 10thNight
36%414%26%17%2
2458
11th to 20thNight
37%5%13%27%17%2
2386
21st to endNight
37%416%26%14%3
2574
February1st to 10thNight
42%5%12%22%14%4
2340
11th to 20thNight
40%5%10%27%14%3
2190
21st to endNight
35%410%24%20%7%
1776
March1st to 10thNight
34%411%24%21%6%
2011
11th to 20thNight
40%5%11%23%17%4
1980
21st to endNight
47%6%11%20%13%2
2178
April1st to 10thNight
31%5%13%24%24%3
1968
11th to 20thNight
37%5%11%25%19%2
1682
21st to endNight
39%6%11%25%17%2
1620
May1st to 10thNight
43%7%13%20%16%2
1620
11th to 20thNight
36%5%14%26%18%1
1594
21st to endNight
35%9%19%23%12%2
1746
June1st to 10thNight
22%9%15%33%18%3
1620
11th to 20thNight
24%8%13%32%18%5%
1620
21st to endNight
21%7%13%33%21%5%
1620
July1st to 10thNight
26%7%16%28%18%5%
1575
11th to 20thNight
17%6%14%31%27%5%
1566
21st to endNight
27%5%13%34%19%2
1673
August1st to 10thNight
23%8%19%31%16%3
1601
11th to 20thNight
25%6%11%34%21%3
1600
21st to endNight
22%6%11%27%26%7%
1829
September1st to 10thNight
26%5%11%29%20%9%
1930
11th to 20thNight
28%6%10%25%25%6%
1980
21st to endNight
26%5%9%25%31%5%
1980
October1st to 10thNight
32%5%9%24%25%5%
2068
11th to 20thNight
29%36%28%26%8%
2160
21st to endNight
32%410%22%27%6%
2376
November1st to 10thNight
24%411%28%26%8%
2351
11th to 20thNight
27%410%29%25%4
2470
21st to endNight
32%410%28%22%4
2470
December1st to 10thNight
33%5%13%28%19%1
2602
11th to 20thNight
36%410%31%18%1
3037
21st to endNight
53%410%22%9%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
15%17%37%21%10%
270
11th to 20thDay
22%15%42%18%3
249
21st to endDay
14%12%49%22%4
264
February1st to 10thDay
18%20%44%13%4
240
11th to 20thDay
17%14%48%15%6%
240
21st to endDay
17%19%46%14%31
198
March1st to 10thDay
13%21%41%19%5%
240
11th to 20thDay
29%11%38%16%5%
240
21st to endDay
27%18%41%11%2
264
April1st to 10thDay
19%19%38%19%5%
250
11th to 20thDay
17%17%37%23%6%
504
21st to endDay
22%18%32%20%7%2
600
May1st to 10thDay
19%14%35%22%9%1
603
11th to 20thDay
19%12%27%26%14%2
625
21st to endDay
16%10%30%26%14%3
679
June1st to 10thDay
6%5%25%35%21%8%
630
11th to 20thDay
7%333%34%19%3
630
21st to endDay
7%7%34%38%12%3
630
July1st to 10thDay
10%315%35%29%7%
621
11th to 20thDay
5%321%39%27%6%
618
21st to endDay
7%217%41%29%4
684
August1st to 10thDay
7%318%39%30%3
626
11th to 20thDay
8%418%42%25%4
615
21st to endDay
9%216%34%29%8%
644
September1st to 10thDay
13%219%39%24%3
317
11th to 20thDay
7%5%24%36%23%4
270
21st to endDay
12%8%31%32%14%3
270
October1st to 10thDay
17%9%30%27%12%6%
270
11th to 20thDay
8%19%42%21%9%1
270
21st to endDay
20%18%32%23%6%2
297
November1st to 10thDay
12%18%31%29%9%1
270
11th to 20thDay
16%17%36%22%8%1
270
21st to endDay
21%12%37%19%9%1
270
December1st to 10thDay
10%12%41%26%9%1
270
11th to 20thDay
14%17%37%24%7%
270
21st to endDay
20%16%41%21%2
297
January1st to 10thNight
13%13%35%32%8%
950
11th to 20thNight
15%10%37%30%7%1
918
21st to endNight
13%9%42%31%4
990
February1st to 10thNight
16%10%42%29%3
900
11th to 20thNight
13%13%40%30%4
795
21st to endNight
15%14%41%25%5%
592
March1st to 10thNight
15%12%42%27%4
571
11th to 20thNight
16%12%36%29%6%
540
21st to endNight
21%14%38%22%5%
594
April1st to 10thNight
14%13%42%26%5%
540
11th to 20thNight
18%15%34%29%41
533
21st to endNight
19%9%38%26%6%1
540
May1st to 10thNight
19%9%32%31%8%1
540
11th to 20thNight
17%7%31%34%10%1
531
21st to endNight
14%7%30%33%15%1
584
June1st to 10thNight
6%425%43%21%1
540
11th to 20thNight
7%332%40%18%
540
21st to endNight
6%332%47%12%
540
July1st to 10thNight
7%117%45%29%1
525
11th to 20thNight
2121%50%22%2
522
21st to endNight
7%216%48%26%1
591
August1st to 10thNight
4220%49%24%1
537
11th to 20thNight
6%217%48%27%1
534
21st to endNight
6%216%45%28%3
594
September1st to 10thNight
10%225%41%20%2
540
11th to 20thNight
10%226%39%21%2
540
21st to endNight
8%427%41%18%1
540
October1st to 10thNight
14%6%29%35%15%2
628
11th to 20thNight
13%9%39%30%9%
720
21st to endNight
16%12%33%29%10%1
792
November1st to 10thNight
9%10%34%36%11%
871
11th to 20thNight
11%12%39%31%6%
950
21st to endNight
15%12%33%32%9%
950
December1st to 10thNight
11%11%36%34%8%
950
11th to 20thNight
17%10%37%31%5%
950
21st to endNight
18%12%36%29%4
1045
Page generated at 2024-01-11 03:22:43. Version ac07

Copyright 2024 Attilla Danko


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