IU Kokomo Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the IU Kokomo Observatory clear sky chart from 2005-11-05 to 2017-09-18.

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
38%
15856
17%
46822
11%
15814
44%
15814
23%
31463

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
16%
900
14%
2506
5%
895
24%
895
14%
1940
January16th to endNight
20%
932
12%
2660
5%
932
26%
932
15%
2040
February1st to 15thNight
21%
701
11%
2125
4%
701
27%
701
16%
1548
February16th to endNight
22%
631
15%
1893
7%
631
30%
631
17%
1363
March1st to 15thNight
26%
720
14%
2146
9%
720
30%
720
16%
1536
March16th to endNight
29%
714
16%
2058
8%
714
37%
714
20%
1453
April1st to 15thNight
30%
539
16%
1797
9%
539
41%
539
21%
1185
April16th to endNight
33%
540
21%
1687
11%
540
43%
540
25%
1082
May1st to 15thNight
37%
540
14%
1620
9%
540
43%
540
21%
1129
May16th to endNight
52%
562
16%
1618
12%
561
56%
561
28%
1052
June1st to 15thNight
59%
540
18%
1440
12%
540
63%
540
38%
873
June16th to endNight
56%
540
18%
1440
12%
540
61%
540
35%
903
July1st to 15thNight
61%
510
16%
1360
13%
510
64%
510
37%
833
July16th to endNight
70%
564
23%
1445
18%
531
74%
531
45%
814
August1st to 15thNight
69%
539
23%
1609
20%
536
71%
536
39%
912
August16th to endNight
67%
573
21%
1897
21%
573
71%
573
35%
1040
September1st to 15thNight
61%
606
27%
1866
23%
606
66%
606
35%
1079
September16th to endNight
63%
669
27%
1848
21%
669
66%
669
36%
1108
October1st to 15thNight
52%
660
28%
1815
22%
660
58%
660
36%
1095
October16th to endNight
31%
704
18%
2276
13%
704
39%
704
21%
1469
November1st to 15thNight
37%
700
26%
2276
18%
700
49%
700
27%
1358
November16th to endNight
27%
720
17%
2340
11%
720
35%
720
17%
1623
December1st to 15thNight
21%
792
11%
2412
5%
792
27%
792
14%
1850
December16th to endNight
16%
960
10%
2688
3%
960
23%
960
11%
2178

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%8%36%5%35%45%7%35%
47973
Night
14%8%36%5%24446%38%
46994
Cloud CoverDay
14%8%36%5%35%45%7%35%
47982
Night
14%8%36%5%24446%38%
46999
TransparencyDay
47%412%21%12%1
47663
Night
46%411%21%13%2
46822
SeeingDay
16%6%24%24%19%8%
5865
Night
18%8%26%30%14%1
15860

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%15%5%7%6%35%34423%
1432
16th to endDay
14%17%6%9%6%34346%22%
1563
February1st to 15thDay
14%13%6%8%7%35%435%25%
1735
16th to endDay
15%13%6%8%5%345%45%27%
1580
March1st to 15thDay
19%12%5%8%5%33346%26%
1803
16th to endDay
18%10%46%5%2445%7%30%
2175
April1st to 15thDay
19%9%35%5%24446%34%
2151
16th to endDay
17%8%36%5%3435%7%35%
2271
May1st to 15thDay
19%9%36%5%4445%6%28%
2331
16th to endDay
12%5%35%5%45%5%5%7%37%
2494
June1st to 15thDay
10%5%25%5%45%45%7%43%
2520
16th to endDay
9%435%6%36%6%6%9%39%
2520
July1st to 15thDay
9%6%25%435%6%6%9%40%
2520
16th to endDay
7%3245%45%6%8%11%40%
2623
August1st to 15thDay
6%425%5%35%6%6%8%45%
2340
16th to endDay
8%425%5%36%5%6%8%42%
2303
September1st to 15thDay
11%5%25%4345%5%7%44%
2082
16th to endDay
11%425%425%45%7%45%
1837
October1st to 15thDay
14%6%25%43445%5%43%
1815
16th to endDay
18%7%35%5%345%5%6%35%
1595
November1st to 15thDay
13%7%35%323335%46%
1582
16th to endDay
18%11%46%5%25%35%6%30%
1620
December1st to 15thDay
19%13%6%9%6%33336%23%
1545
16th to endDay
23%15%6%7%5%25%345%19%
1536
January1st to 15thNight
19%13%5%9%6%3333427%
2506
16th to endNight
15%14%6%9%6%24335%26%
2660
February1st to 15thNight
16%12%5%7%5%24345%31%
2123
16th to endNight
15%12%5%8%6%34345%31%
1893
March1st to 15thNight
17%10%5%6%5%2445%5%31%
2133
16th to endNight
15%9%38%5%33447%33%
2058
April1st to 15thNight
15%7%35%6%35%5%46%37%
1797
16th to endNight
16%7%25%5%23447%40%
1687
May1st to 15thNight
20%6%35%5%34447%33%
1620
16th to endNight
12%5%25%426%6%6%8%40%
1616
June1st to 15thNight
8%425%33345%7%50%
1440
16th to endNight
8%5%24425%5%5%9%45%
1440
July1st to 15thNight
7%4235%345%6%10%45%
1440
16th to endNight
5%32443346%8%54%
1543
August1st to 15thNight
5%325%4345%8%9%48%
1620
16th to endNight
6%325%5%2346%7%51%
1897
September1st to 15thNight
10%424423346%52%
1866
16th to endNight
10%41442345%7%50%
1848
October1st to 15thNight
11%5%1342436%7%49%
1815
16th to endNight
18%6%36%423446%40%
2276
November1st to 15thNight
12%6%3432345%6%46%
2276
16th to endNight
19%9%46%5%33346%32%
2340
December1st to 15thNight
21%11%7%9%6%2424426%
2412
16th to endNight
23%14%5%8%6%34435%20%
2688

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
19%15%5%8%5%35%34423%
1432
16th to endDay
14%17%6%8%6%3435%6%22%
1563
February1st to 15thDay
14%13%6%8%7%35%43425%
1735
16th to endDay
15%12%6%8%6%245%45%27%
1580
March1st to 15thDay
20%12%5%8%5%24346%26%
1813
16th to endDay
18%10%46%5%2445%7%30%
2174
April1st to 15thDay
19%8%26%424446%34%
2151
16th to endDay
17%7%27%5%3335%6%35%
2271
May1st to 15thDay
20%9%45%6%44446%29%
2331
16th to endDay
13%6%25%6%45%45%8%37%
2494
June1st to 15thDay
11%5%25%6%3446%6%43%
2520
16th to endDay
10%425%6%36%5%6%9%39%
2520
July1st to 15thDay
9%6%25%436%5%6%9%40%
2520
16th to endDay
7%3146%36%6%7%10%41%
2623
August1st to 15thDay
6%425%5%35%5%6%8%45%
2340
16th to endDay
8%425%6%35%5%6%8%42%
2303
September1st to 15thDay
12%4245%35%45%7%44%
2082
16th to endDay
11%424425%45%7%45%
1837
October1st to 15thDay
14%6%25%434445%44%
1815
16th to endDay
18%7%35%5%3445%6%35%
1595
November1st to 15thDay
13%7%25%323345%46%
1582
16th to endDay
19%11%36%5%3435%5%30%
1620
December1st to 15thDay
19%13%5%10%6%24336%24%
1545
16th to endDay
23%16%5%8%5%35%335%19%
1536
January1st to 15thNight
19%13%5%9%6%3333427%
2506
16th to endNight
15%14%7%9%6%3433427%
2660
February1st to 15thNight
16%13%5%7%5%23335%31%
2116
16th to endNight
15%12%47%6%24445%31%
1893
March1st to 15thNight
17%10%5%6%5%2445%5%31%
2146
16th to endNight
15%9%37%5%33447%33%
2058
April1st to 15thNight
16%7%35%5%35%446%37%
1797
16th to endNight
16%6%35%423447%40%
1687
May1st to 15thNight
20%6%35%5%3445%6%33%
1619
16th to endNight
12%425%425%6%6%8%40%
1616
June1st to 15thNight
8%425%4335%5%7%50%
1440
16th to endNight
8%6%24425%5%49%46%
1440
July1st to 15thNight
7%4236%336%6%10%46%
1440
16th to endNight
432442346%8%54%
1543
August1st to 15thNight
5%3244345%8%9%48%
1620
16th to endNight
6%315%5%2345%7%52%
1897
September1st to 15thNight
11%424423446%52%
1866
16th to endNight
10%424433447%50%
1848
October1st to 15thNight
11%42343336%6%49%
1815
16th to endNight
18%6%36%423336%40%
2276
November1st to 15thNight
12%7%34323446%46%
2276
16th to endNight
19%10%46%5%24346%32%
2340
December1st to 15thNight
21%12%6%9%6%2324426%
2412
16th to endNight
23%14%5%8%5%34335%20%
2688

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
63%310%15%7%
1433
16th to endDay
62%313%13%6%
1563
February1st to 15thDay
62%310%15%7%
1737
16th to endDay
58%413%19%5%
1580
March1st to 15thDay
59%312%17%6%
1813
16th to endDay
52%415%20%5%1
2175
April1st to 15thDay
49%410%22%11%
2151
16th to endDay
48%411%20%9%5%
2271
May1st to 15thDay
55%5%12%18%8%
2331
16th to endDay
43%5%11%21%14%2
2498
June1st to 15thDay
38%411%25%17%1
2520
16th to endDay
38%7%14%20%15%2
2520
July1st to 15thDay
39%5%10%23%17%2
2371
16th to endDay
33%6%18%25%13%2
2458
August1st to 15thDay
33%6%13%26%18%1
2327
16th to endDay
36%6%12%23%16%5%
2303
September1st to 15thDay
38%411%22%18%4
2082
16th to endDay
36%49%26%21%1
1837
October1st to 15thDay
41%410%24%17%2
1815
16th to endDay
47%411%24%11%
1595
November1st to 15thDay
40%310%24%18%3
1582
16th to endDay
55%312%21%7%
1620
December1st to 15thDay
63%210%18%4
1545
16th to endDay
67%410%13%3
1536
January1st to 15thNight
61%27%17%10%
2506
16th to endNight
61%212%17%6%
2660
February1st to 15thNight
56%313%17%8%1
2125
16th to endNight
54%311%21%8%
1893
March1st to 15thNight
54%311%19%8%2
2146
16th to endNight
50%5%12%22%8%1
2058
April1st to 15thNight
46%410%23%13%1
1797
16th to endNight
43%410%22%14%5%
1687
May1st to 15thNight
49%5%12%21%10%1
1620
16th to endNight
39%7%12%21%15%3
1618
June1st to 15thNight
31%5%11%26%21%2
1440
16th to endNight
35%5%15%22%17%4
1440
July1st to 15thNight
32%5%14%21%20%4
1360
16th to endNight
26%417%29%18%4
1445
August1st to 15thNight
28%6%14%24%24%2
1609
16th to endNight
29%5%13%24%21%5%
1897
September1st to 15thNight
32%49%25%21%6%
1866
16th to endNight
33%38%26%24%2
1848
October1st to 15thNight
34%310%27%22%2
1815
16th to endNight
45%310%26%12%1
2276
November1st to 15thNight
37%48%24%20%4
2276
16th to endNight
52%311%23%9%
2340
December1st to 15thNight
61%39%16%7%
2412
16th to endNight
66%39%14%5%
2688

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
28%16%34%12%6%1
90
16th to endDay
29%12%38%17%2
96
February1st to 15thDay
15%18%46%15%3
90
16th to endDay
20%11%35%22%9%
81
March1st to 15thDay
33%12%33%17%2
103
16th to endDay
29%7%29%21%10%1
288
April1st to 15thDay
25%9%31%21%10%2
270
16th to endDay
21%8%29%22%12%5%
270
May1st to 15thDay
24%11%26%25%8%4
288
16th to endDay
18%427%23%17%8%
394
June1st to 15thDay
11%425%31%22%5%
495
16th to endDay
13%429%27%18%6%
495
July1st to 15thDay
12%222%28%21%12%
475
16th to endDay
8%212%31%29%16%
483
August1st to 15thDay
10%28%25%30%21%
313
16th to endDay
10%114%23%37%12%
332
September1st to 15thDay
13%213%28%29%12%
315
16th to endDay
14%311%22%36%11%
262
October1st to 15thDay
15%5%23%28%20%7%
255
16th to endDay
24%10%37%26%
104
November1st to 15thDay
10%10%21%22%27%8%
90
16th to endDay
30%12%37%12%7%
90
December1st to 15thDay
22%14%40%15%7%
90
16th to endDay
29%20%39%7%3
96
January1st to 15thNight
26%14%36%18%4
900
16th to endNight
21%14%34%26%3
932
February1st to 15thNight
24%11%34%26%3
704
16th to endNight
22%11%35%26%4
631
March1st to 15thNight
21%12%32%26%6%
720
16th to endNight
20%8%34%26%7%
714
April1st to 15thNight
19%10%36%25%7%
539
16th to endNight
20%6%33%26%10%1
540
May1st to 15thNight
22%6%25%34%10%
540
16th to endNight
13%421%38%18%2
563
June1st to 15thNight
9%221%46%18%
540
16th to endNight
11%221%42%22%
540
July1st to 15thNight
9%216%43%25%2
510
16th to endNight
7%110%37%38%4
564
August1st to 15thNight
6%12%41%31%6%
539
16th to endNight
7%113%35%36%6%
573
September1st to 15thNight
13%216%34%28%4
606
16th to endNight
12%414%34%30%3
669
October1st to 15thNight
14%7%20%34%19%3
660
16th to endNight
22%10%31%25%9%
704
November1st to 15thNight
17%9%32%28%12%1
700
16th to endNight
25%13%29%22%9%
720
December1st to 15thNight
28%11%31%22%5%
792
16th to endNight
29%13%30%20%4
960
Page generated at 2017-09-19 07:32:27. Version ac04

Copyright 2017 A. Danko


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