Topeka
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Topeka clear sky chart from 2005-11-05 to 2017-08-12.

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%
15784
24%
46753
14%
15738
50%
15738
34%
27216

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
32%
900
24%
2327
8%
895
43%
895
35%
1427
January16th to endNight
30%
960
27%
2496
10%
960
41%
960
34%
1540
February1st to 15thNight
26%
880
17%
2288
6%
876
34%
876
25%
1574
February16th to endNight
30%
659
25%
1921
8%
659
43%
659
31%
1153
March1st to 15thNight
33%
540
23%
1980
14%
540
46%
540
25%
1112
March16th to endNight
27%
576
16%
2112
11%
576
36%
576
21%
1318
April1st to 15thNight
31%
539
21%
1881
12%
539
46%
539
29%
1036
April16th to endNight
30%
540
22%
1662
12%
540
45%
540
25%
1067
May1st to 15thNight
35%
539
20%
1620
14%
539
44%
539
26%
1012
May16th to endNight
44%
562
18%
1685
13%
561
50%
561
35%
965
June1st to 15thNight
54%
540
19%
1539
10%
540
59%
540
42%
848
June16th to endNight
60%
540
25%
1586
15%
540
65%
540
54%
760
July1st to 15thNight
65%
510
18%
1530
14%
510
68%
510
44%
805
July16th to endNight
68%
564
26%
1594
23%
531
72%
531
43%
854
August1st to 15thNight
75%
527
24%
1575
27%
524
78%
524
45%
824
August16th to endNight
66%
525
26%
1633
28%
525
70%
525
41%
867
September1st to 15thNight
56%
495
26%
1741
25%
495
64%
495
31%
982
September16th to endNight
61%
492
30%
1815
28%
492
69%
492
38%
894
October1st to 15thNight
44%
630
29%
1950
20%
630
50%
630
32%
1128
October16th to endNight
38%
704
30%
2112
14%
704
50%
704
40%
1118
November1st to 15thNight
43%
802
30%
2202
14%
802
54%
802
42%
1200
November16th to endNight
34%
900
27%
2427
9%
900
47%
900
37%
1414
December1st to 15thNight
30%
900
20%
2520
8%
900
40%
900
27%
1615
December16th to endNight
31%
960
24%
2557
9%
960
42%
960
27%
1703

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
9%5%2418%23346%40%
47185
Night
8%41318%23345%44%
46948
Cloud CoverDay
11%6%25%42445%7%45%
47183
Night
10%5%24424446%50%
46948
TransparencyDay
37%313%26%16%2
46883
Night
33%312%27%18%3
46753
SeeingDay
13%8%27%30%16%3
5762
Night
13%8%31%33%12%1
15786

By Month

Percentage Cloud Cover SW (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
8%425%21%3233439%
1611
16th to endDay
8%8%3420%12335%38%
1728
February1st to 15thDay
9%7%35%20%2225%5%34%
1575
16th to endDay
8%8%3419%22345%37%
1560
March1st to 15thDay
8%7%25%21%24445%32%
1980
16th to endDay
15%8%2420%1333433%
2112
April1st to 15thDay
12%5%2420%13345%35%
2067
16th to endDay
14%7%26%21%2334428%
2295
May1st to 15thDay
11%6%2421%23335%35%
2331
16th to endDay
12%5%2421%2345%6%31%
2430
June1st to 15thDay
6%32420%2345%7%39%
2409
16th to endDay
22320%2345%8%46%
2359
July1st to 15thDay
7%31313%245%6%7%44%
2340
16th to endDay
431321%2435%7%42%
2466
August1st to 15thDay
6%31313%2446%8%44%
2289
16th to endDay
6%415%13%2445%6%46%
2217
September1st to 15thDay
10%5%2414%23346%42%
1887
16th to endDay
5%31313%14446%48%
1815
October1st to 15thDay
10%5%1412%23335%47%
1669
16th to endDay
9%41312%12435%51%
1760
November1st to 15thDay
6%31218%13235%51%
1653
16th to endDay
11%42319%1222346%
1530
December1st to 15thDay
13%7%25%20%12335%33%
1440
16th to endDay
9%7%45%21%1322435%
1662
January1st to 15thNight
6%5%1421%23245%42%
2327
16th to endNight
7%6%2420%2333441%
2496
February1st to 15thNight
8%8%25%20%2423336%
2278
16th to endNight
8%5%1419%23335%41%
1921
March1st to 15thNight
8%6%2421%2323439%
1980
16th to endNight
15%6%1320%13335%35%
2112
April1st to 15thNight
8%5%2419%22245%42%
1881
16th to endNight
13%5%2420%24346%32%
1662
May1st to 15thNight
11%5%1319%23336%39%
1619
16th to endNight
10%41320%2235%7%39%
1683
June1st to 15thNight
5%2319%2325%7%46%
1539
16th to endNight
1219%1335%7%54%
1586
July1st to 15thNight
5%21213%2335%7%52%
1620
16th to endNight
321320%2345%6%45%
1702
August1st to 15thNight
32213%2446%8%50%
1585
16th to endNight
6%21412%22345%55%
1633
September1st to 15thNight
10%41413%23346%45%
1741
16th to endNight
5%21313%23446%52%
1815
October1st to 15thNight
13%32312%2233448%
1950
16th to endNight
7%31312%12225%57%
2112
November1st to 15thNight
5%41316%22225%53%
2202
16th to endNight
10%31219%1223348%
2427
December1st to 15thNight
11%7%2420%2334436%
2520
16th to endNight
11%8%25%19%1233437%
2557

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
10%5%35%443345%48%
1611
16th to endDay
10%8%44422446%46%
1728
February1st to 15thDay
10%8%5%6%42435%7%40%
1575
16th to endDay
9%9%35%33335%6%45%
1560
March1st to 15thDay
11%8%35%5%245%5%7%38%
1980
16th to endDay
19%9%35%423345%37%
2110
April1st to 15thDay
15%6%35%423446%42%
2067
16th to endDay
17%8%36%5%2435%5%36%
2295
May1st to 15thDay
14%8%35%5%34436%39%
2331
16th to endDay
14%6%35%4345%6%7%38%
2430
June1st to 15thDay
8%435%4245%6%8%45%
2409
16th to endDay
4314335%5%6%9%53%
2359
July1st to 15thDay
8%324435%5%7%9%44%
2340
16th to endDay
6%3245%25%47%8%49%
2466
August1st to 15thDay
7%3244245%6%9%47%
2289
16th to endDay
7%425%5%2446%7%49%
2217
September1st to 15thDay
12%6%245%33346%45%
1887
16th to endDay
6%3145%25%447%52%
1815
October1st to 15thDay
11%6%24322347%51%
1669
16th to endDay
12%413323436%54%
1760
November1st to 15thDay
7%313423346%58%
1653
16th to endDay
14%42341233453%
1530
December1st to 15thDay
14%8%35%422447%41%
1440
16th to endDay
12%8%46%5%14346%39%
1662
January1st to 15thNight
7%6%245%2435%6%50%
2327
16th to endNight
8%7%35%5%2344451%
2496
February1st to 15thNight
10%10%46%5%3435%5%40%
2278
16th to endNight
9%6%25%424346%49%
1921
March1st to 15thNight
9%6%245%25%346%48%
1980
16th to endNight
18%7%23414447%40%
2112
April1st to 15thNight
10%5%24333347%50%
1881
16th to endNight
17%6%25%424446%41%
1662
May1st to 15thNight
13%6%34324448%43%
1619
16th to endNight
10%41432435%10%47%
1683
June1st to 15thNight
6%22433436%8%54%
1539
16th to endNight
311221346%10%61%
1586
July1st to 15thNight
7%21232446%9%54%
1620
16th to endNight
42144345%6%8%53%
1702
August1st to 15thNight
323435%5%6%9%53%
1585
16th to endNight
8%324322345%58%
1633
September1st to 15thNight
11%41443445%6%48%
1741
16th to endNight
6%313424447%56%
1815
October1st to 15thNight
14%324323345%52%
1950
16th to endNight
10%413312225%60%
2112
November1st to 15thNight
7%423223336%60%
2202
16th to endNight
12%422313345%56%
2427
December1st to 15thNight
12%7%35%5%3435%5%44%
2520
16th to endNight
14%9%36%313346%42%
2557

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
38%213%26%16%2
1612
16th to endDay
38%216%27%13%1
1728
February1st to 15thDay
44%215%26%8%2
1576
16th to endDay
40%213%27%14%2
1560
March1st to 15thDay
44%213%24%13%2
1980
16th to endDay
50%313%22%9%1
2112
April1st to 15thDay
42%211%24%18%
2067
16th to endDay
48%311%24%12%
2295
May1st to 15thDay
45%311%24%12%
2331
16th to endDay
43%415%22%11%1
2434
June1st to 15thDay
33%5%14%28%16%2
2409
16th to endDay
26%415%31%20%2
2359
July1st to 15thDay
33%5%15%29%13%3
2201
16th to endDay
27%413%33%16%3
2311
August1st to 15thDay
31%5%14%29%18%2
2275
16th to endDay
33%412%25%17%6%
2217
September1st to 15thDay
38%211%22%17%6%
1887
16th to endDay
30%312%28%22%1
1815
October1st to 15thDay
33%210%26%23%4
1669
16th to endDay
31%211%27%22%4
1760
November1st to 15thDay
27%211%28%22%6%
1653
16th to endDay
34%29%32%19%1
1530
December1st to 15thDay
42%315%26%11%
1440
16th to endDay
45%312%23%12%1
1662
January1st to 15thNight
34%215%26%19%1
2327
16th to endNight
34%314%27%18%2
2496
February1st to 15thNight
46%211%25%11%2
2288
16th to endNight
35%212%26%19%3
1921
March1st to 15thNight
37%212%25%16%5%
1980
16th to endNight
43%414%22%12%2
2112
April1st to 15thNight
34%211%27%21%2
1881
16th to endNight
43%39%26%16%1
1662
May1st to 15thNight
39%412%23%17%1
1620
16th to endNight
31%322%24%14%1
1685
June1st to 15thNight
26%417%32%15%3
1539
16th to endNight
17%315%37%22%3
1586
July1st to 15thNight
25%316%32%18%4
1530
16th to endNight
26%411%33%21%2
1594
August1st to 15thNight
24%317%33%17%4
1575
16th to endNight
28%29%29%22%7%
1633
September1st to 15thNight
35%211%23%18%7%
1741
16th to endNight
26%210%29%26%3
1815
October1st to 15thNight
35%28%24%23%6%
1950
16th to endNight
27%28%32%24%4
2112
November1st to 15thNight
26%212%25%23%8%
2202
16th to endNight
31%29%33%19%3
2427
December1st to 15thNight
40%313%29%12%
2520
16th to endNight
43%313%23%13%2
2557

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
23%15%40%17%3
90
16th to endDay
14%21%41%17%31
96
February1st to 15thDay
12%26%40%17%3
90
16th to endDay
11%24%43%8%12%
81
March1st to 15thDay
18%21%44%13%2
90
16th to endDay
27%16%40%12%3
96
April1st to 15thDay
20%14%28%27%9%
186
16th to endDay
24%12%35%18%7%
405
May1st to 15thDay
18%10%34%23%10%1
468
16th to endDay
19%9%32%25%11%2
517
June1st to 15thDay
9%5%27%36%16%4
495
16th to endDay
45%33%36%16%3
495
July1st to 15thDay
12%219%36%25%4
475
16th to endDay
6%112%41%32%5%
515
August1st to 15thDay
8%112%40%29%6%
474
16th to endDay
9%316%38%27%6%
385
September1st to 15thDay
11%325%38%15%6%
162
16th to endDay
11%228%40%12%5%
90
October1st to 15thDay
6%12%32%31%8%8%
90
16th to endDay
8%11%43%25%11%
96
November1st to 15thDay
8%331%40%12%4
90
16th to endDay
34%14%37%8%4
90
December1st to 15thDay
16%21%42%12%43
90
16th to endDay
22%27%27%20%2
96
January1st to 15thNight
11%13%38%28%7%
900
16th to endNight
13%12%38%30%5%
960
February1st to 15thNight
16%11%38%29%4
880
16th to endNight
13%12%40%28%5%
659
March1st to 15thNight
13%11%37%30%7%1
540
16th to endNight
22%10%36%26%4
576
April1st to 15thNight
14%12%38%29%5%
539
16th to endNight
22%9%35%25%7%
540
May1st to 15thNight
16%8%35%28%10%
540
16th to endNight
12%6%32%34%12%1
563
June1st to 15thNight
7%328%40%19%
540
16th to endNight
4329%44%16%1
540
July1st to 15thNight
10%116%47%22%1
510
16th to endNight
6%16%47%27%2
564
August1st to 15thNight
5%11%49%31%2
527
16th to endNight
8%115%39%30%3
525
September1st to 15thNight
14%219%38%22%2
495
16th to endNight
5%322%42%23%3
492
October1st to 15thNight
15%5%30%30%16%1
630
16th to endNight
12%8%37%29%10%
704
November1st to 15thNight
10%11%31%33%12%
802
16th to endNight
15%11%36%27%8%
900
December1st to 15thNight
17%11%34%30%4
900
16th to endNight
19%9%32%32%6%
960
Page generated at 2017-08-13 13:16:45. Version ac04

Copyright 2017 A. Danko


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