Indianapolis
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Indianapolis clear sky chart from 2005-11-06 to 2024-01-31.

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
34%
24421
18%
74829
11%
24361
42%
24361
21%
50708

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
18%
950
14%
2648
5%
946
26%
946
13%
2024
January11th to 20thNight
13%
950
11%
2660
4%
950
20%
950
12%
2129
January21st to endNight
17%
964
11%
2836
5%
964
24%
964
12%
2187
February1st to 10thNight
17%
720
11%
2160
4%
720
22%
720
13%
1646
February11th to 20thNight
19%
702
14%
2098
5%
699
28%
699
15%
1509
February21st to endNight
16%
592
14%
1776
4%
592
26%
592
13%
1330
March1st to 10thNight
21%
720
15%
2160
7%
720
28%
720
18%
1500
March11th to 20thNight
23%
720
17%
2048
7%
720
31%
720
20%
1425
March21st to endNight
23%
715
15%
2101
6%
715
33%
715
17%
1523
April1st to 10thNight
30%
540
19%
1800
11%
540
41%
540
20%
1163
April11th to 20thNight
30%
533
20%
1775
13%
533
41%
533
21%
1148
April21st to endNight
23%
540
18%
1648
5%
540
36%
540
20%
1129
May1st to 10thNight
26%
540
13%
1620
6%
540
33%
540
17%
1168
May11th to 20thNight
39%
531
17%
1593
10%
531
46%
531
24%
1067
May21st to endNight
47%
584
17%
1691
10%
582
54%
582
29%
1075
June1st to 10thNight
50%
540
18%
1440
12%
540
55%
540
35%
897
June11th to 20thNight
49%
540
21%
1440
14%
540
56%
540
34%
907
June21st to endNight
53%
540
20%
1440
13%
540
60%
540
35%
892
July1st to 10thNight
62%
525
17%
1400
12%
525
64%
525
34%
883
July11th to 20thNight
59%
522
21%
1392
14%
522
64%
522
43%
813
July21st to endNight
58%
591
24%
1559
16%
558
64%
558
39%
913
August1st to 10thNight
63%
537
21%
1600
17%
534
65%
534
36%
926
August11th to 20thNight
62%
534
23%
1692
21%
534
66%
534
33%
969
August21st to endNight
63%
594
23%
1980
21%
594
69%
594
37%
1062
September1st to 10thNight
57%
550
23%
1810
19%
550
64%
550
30%
1070
September11th to 20thNight
61%
720
30%
1980
23%
720
67%
720
40%
1148
September21st to endNight
50%
720
27%
1980
18%
720
56%
720
33%
1220
October1st to 10thNight
48%
720
26%
1980
18%
720
56%
720
36%
1184
October11th to 20thNight
33%
720
23%
2115
13%
720
44%
720
26%
1342
October21st to endNight
26%
792
19%
2574
12%
792
36%
792
20%
1678
November1st to 10thNight
34%
740
24%
2406
16%
740
46%
740
28%
1403
November11th to 20thNight
28%
760
23%
2470
12%
760
42%
760
21%
1585
November21st to endNight
25%
760
19%
2470
11%
760
35%
760
16%
1737
December1st to 10thNight
18%
760
14%
2470
6%
760
28%
760
14%
1791
December11th to 20thNight
22%
916
15%
3159
6%
914
28%
914
13%
2260
December21st to endNight
16%
1039
7%
4858
4%
1026
22%
1026
6%
4005

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%8%46%5%35%5%5%7%36%
75008
Night
16%9%46%5%3445%7%38%
75130
TransparencyDay
46%6%12%21%13%2
74715
Night
46%6%11%21%14%2
74944
SeeingDay
20%13%28%22%13%5%
14461
Night
20%11%29%26%13%1
24428

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
18%14%5%10%7%35%45%6%24%
1517
11th to 20thDay
20%13%7%11%6%5%4445%22%
1520
21st to endDay
18%17%7%9%5%35%446%22%
1741
February1st to 10thDay
19%13%8%8%5%44445%25%
1800
11th to 20thDay
16%12%49%6%5%45%5%6%27%
1748
21st to endDay
19%15%6%7%6%23345%30%
1480
March1st to 10thDay
18%10%47%6%34447%32%
1800
11th to 20thDay
19%10%37%5%35%45%6%33%
1910
21st to endDay
22%12%5%6%6%35%45%6%27%
2270
April1st to 10thDay
16%9%46%6%34447%36%
2160
11th to 20thDay
17%8%35%5%4445%7%37%
2134
21st to endDay
21%7%36%5%34447%35%
2312
May1st to 10thDay
20%8%46%6%35%5%46%33%
2340
11th to 20thDay
20%7%36%6%45%45%6%34%
2301
21st to endDay
10%6%36%7%5%6%5%7%9%36%
2580
June1st to 10thDay
12%5%25%7%45%5%6%8%41%
2520
11th to 20thDay
10%5%25%5%35%5%6%9%45%
2520
21st to endDay
10%5%35%6%45%5%7%9%41%
2520
July1st to 10thDay
11%6%25%6%45%6%7%10%39%
2520
11th to 20thDay
8%4245%346%7%11%45%
2520
21st to endDay
10%325%5%36%7%7%10%42%
2663
August1st to 10thDay
10%425%435%6%7%9%45%
2327
11th to 20thDay
11%5%246%47%6%7%11%38%
2205
21st to endDay
7%5%25%5%35%5%7%10%47%
2376
September1st to 10thDay
12%5%35%5%35%45%7%45%
2131
11th to 20thDay
11%5%245%35%5%6%7%48%
1980
21st to endDay
12%5%2443445%7%51%
1980
October1st to 10thDay
13%5%25%5%3445%7%46%
1980
11th to 20thDay
15%6%25%5%25%5%5%7%42%
1839
21st to endDay
20%9%36%5%3445%7%34%
1782
November1st to 10thDay
10%6%35%43345%6%51%
1672
11th to 20thDay
16%10%47%5%34447%36%
1710
21st to endDay
20%10%46%5%24345%35%
1710
December1st to 10thDay
21%13%6%7%5%44346%28%
1710
11th to 20thDay
17%15%6%9%6%24445%28%
1947
21st to endDay
24%20%9%8%6%33345%16%
2783
January1st to 10thNight
19%12%5%8%6%34446%28%
2648
11th to 20thNight
19%15%6%9%8%3443425%
2660
21st to endNight
18%14%7%9%7%3444427%
2836
February1st to 10thNight
21%12%6%8%6%34345%27%
2160
11th to 20thNight
16%11%5%8%7%2445%6%32%
2098
21st to endNight
20%13%47%5%35%445%30%
1776
March1st to 10thNight
17%10%46%5%34446%36%
2160
11th to 20thNight
17%8%36%5%4445%6%38%
2048
21st to endNight
22%9%36%5%34447%33%
2101
April1st to 10thNight
14%8%45%425%5%5%8%40%
1800
11th to 20thNight
17%8%345%34348%40%
1775
21st to endNight
19%6%36%5%35%5%6%6%37%
1648
May1st to 10thNight
18%8%46%5%345%5%8%32%
1620
11th to 20thNight
18%7%25%5%2445%7%40%
1592
21st to endNight
9%425%6%46%6%7%11%40%
1690
June1st to 10thNight
9%6%25%5%2445%7%49%
1440
11th to 20thNight
10%5%35%425%45%8%48%
1440
21st to endNight
7%4245%35%6%8%10%45%
1440
July1st to 10thNight
9%4245%445%7%11%46%
1440
11th to 20thNight
8%3243345%6%8%55%
1440
21st to endNight
9%43432445%8%54%
1651
August1st to 10thNight
8%4235%35%5%7%8%50%
1611
11th to 20thNight
7%4246%25%5%7%8%50%
1692
21st to endNight
7%4144335%6%8%54%
1980
September1st to 10thNight
12%6%34434447%48%
1810
11th to 20thNight
8%4244345%5%8%54%
1980
21st to endNight
11%5%245%33447%51%
1980
October1st to 10thNight
9%4245%3435%7%53%
1980
11th to 20thNight
19%6%2443435%6%45%
2115
21st to endNight
20%8%26%5%24446%40%
2574
November1st to 10thNight
13%7%2442346%5%49%
2406
11th to 20thNight
15%8%46%5%2445%7%40%
2470
21st to endNight
20%12%46%5%3345%5%34%
2470
December1st to 10thNight
19%11%5%8%6%33446%30%
2470
11th to 20thNight
18%14%5%7%5%23445%32%
3245
21st to endNight
25%19%6%8%5%3444417%
4884

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
61%49%16%9%
1518
11th to 20thDay
65%5%10%15%5%
1520
21st to endDay
63%5%10%17%41
1741
February1st to 10thDay
62%5%9%16%8%1
1800
11th to 20thDay
58%5%10%19%8%1
1758
21st to endDay
58%49%19%8%2
1480
March1st to 10thDay
53%5%10%22%10%
1800
11th to 20thDay
53%5%13%18%10%1
1910
21st to endDay
59%5%11%18%5%1
2270
April1st to 10thDay
47%7%12%20%13%1
2160
11th to 20thDay
48%5%12%22%10%3
2134
21st to endDay
50%6%11%20%11%3
2312
May1st to 10thDay
52%7%11%20%9%1
2340
11th to 20thDay
50%7%11%17%13%1
2305
21st to endDay
42%10%13%19%14%2
2580
June1st to 10thDay
39%7%13%23%15%3
2520
11th to 20thDay
35%8%13%22%20%3
2520
21st to endDay
37%8%15%20%15%4
2520
July1st to 10thDay
38%10%14%20%15%3
2451
11th to 20thDay
31%9%16%26%18%1
2445
21st to endDay
33%11%16%22%15%3
2515
August1st to 10thDay
33%9%14%29%14%2
2314
11th to 20thDay
37%9%15%25%14%1
2205
21st to endDay
30%8%14%23%17%7%
2376
September1st to 10thDay
37%7%11%24%16%5%
2131
11th to 20thDay
33%6%12%26%19%3
1980
21st to endDay
33%5%11%26%23%2
1980
October1st to 10thDay
37%6%11%23%20%3
1980
11th to 20thDay
39%7%9%24%19%2
1839
21st to endDay
51%5%11%20%13%1
1782
November1st to 10thDay
34%413%28%17%4
1672
11th to 20thDay
48%5%8%21%14%3
1710
21st to endDay
52%410%22%11%2
1710
December1st to 10thDay
59%5%10%17%9%
1710
11th to 20thDay
59%5%8%20%7%1
1944
21st to endDay
71%5%9%10%5%
2783
January1st to 10thNight
58%5%8%18%11%1
2648
11th to 20thNight
64%49%16%6%1
2660
21st to endNight
61%5%10%16%8%1
2836
February1st to 10thNight
61%411%16%7%1
2160
11th to 20thNight
53%5%11%19%11%1
2099
21st to endNight
57%6%10%16%10%2
1776
March1st to 10thNight
49%5%10%22%13%1
2160
11th to 20thNight
48%5%11%22%11%3
2048
21st to endNight
52%5%10%22%8%2
2101
April1st to 10thNight
43%6%11%24%13%2
1800
11th to 20thNight
43%5%9%20%17%5%
1775
21st to endNight
46%7%10%20%13%4
1648
May1st to 10thNight
50%7%10%19%10%2
1620
11th to 20thNight
43%7%13%21%14%2
1593
21st to endNight
35%9%16%22%13%5%
1691
June1st to 10thNight
34%6%11%25%20%3
1440
11th to 20thNight
34%7%11%24%20%4
1440
21st to endNight
30%9%16%23%18%4
1440
July1st to 10thNight
32%9%16%22%16%6%
1400
11th to 20thNight
26%7%16%29%20%3
1392
21st to endNight
28%7%14%29%18%4
1559
August1st to 10thNight
29%8%16%28%18%2
1600
11th to 20thNight
30%8%14%28%19%2
1692
21st to endNight
26%8%16%23%21%6%
1980
September1st to 10thNight
34%7%12%22%20%6%
1810
11th to 20thNight
27%6%10%28%24%4
1980
21st to endNight
33%6%9%23%24%4
1980
October1st to 10thNight
30%6%12%24%24%3
1980
11th to 20thNight
41%5%8%24%21%2
2115
21st to endNight
45%5%11%22%15%2
2574
November1st to 10thNight
35%411%24%22%3
2406
11th to 20thNight
43%5%10%22%17%3
2470
21st to endNight
53%49%22%11%
2470
December1st to 10thNight
55%5%10%19%10%
2470
11th to 20thNight
54%5%10%19%12%1
3247
21st to endNight
70%5%8%11%5%
4884

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
27%21%32%17%3
270
11th to 20thDay
32%19%36%9%4
270
21st to endDay
32%20%32%11%3
294
February1st to 10thDay
30%26%31%11%2
240
11th to 20thDay
28%26%30%13%3
240
21st to endDay
31%28%32%8%1
198
March1st to 10thDay
28%28%36%8%1
240
11th to 20thDay
31%17%34%12%5%1
350
21st to endDay
35%18%28%13%5%1
462
April1st to 10thDay
20%21%34%17%7%1
420
11th to 20thDay
26%18%25%20%8%1
412
21st to endDay
29%18%31%14%7%2
420
May1st to 10thDay
25%15%32%19%7%2
423
11th to 20thDay
22%13%32%19%8%6%
447
21st to endDay
15%9%29%22%16%9%
534
June1st to 10thDay
13%8%33%29%13%4
630
11th to 20thDay
13%7%32%30%13%5%
630
21st to endDay
14%8%32%26%15%4
630
July1st to 10thDay
13%322%27%23%12%
621
11th to 20thDay
8%429%32%18%8%
618
21st to endDay
11%5%22%34%18%10%
604
August1st to 10thDay
11%417%31%25%12%
446
11th to 20thDay
15%422%27%22%10%
439
21st to endDay
8%319%33%28%9%
495
September1st to 10thDay
14%8%18%29%26%6%
450
11th to 20thDay
9%418%27%31%11%
450
21st to endDay
16%10%23%21%22%8%
450
October1st to 10thDay
15%8%29%27%15%6%
450
11th to 20thDay
18%19%32%21%9%1
384
21st to endDay
32%15%38%14%1
297
November1st to 10thDay
15%21%33%22%7%1
270
11th to 20thDay
28%20%26%19%6%1
270
21st to endDay
28%16%37%17%2
270
December1st to 10thDay
25%27%33%11%31
270
11th to 20thDay
24%21%37%13%4
270
21st to endDay
34%20%29%14%4
297
January1st to 10thNight
24%20%30%21%4
950
11th to 20thNight
27%16%37%16%4
950
21st to endNight
25%19%30%24%3
964
February1st to 10thNight
28%16%33%21%3
720
11th to 20thNight
23%21%32%20%3
703
21st to endNight
28%16%35%18%3
592
March1st to 10thNight
22%17%34%22%5%
720
11th to 20thNight
22%15%36%20%6%1
720
21st to endNight
27%12%32%23%5%1
715
April1st to 10thNight
18%16%31%27%7%1
540
11th to 20thNight
21%12%31%26%9%
533
21st to endNight
23%13%36%20%7%1
540
May1st to 10thNight
20%10%37%25%8%
540
11th to 20thNight
21%7%26%30%14%1
531
21st to endNight
9%429%35%21%2
584
June1st to 10thNight
10%428%42%14%1
540
11th to 20thNight
14%327%36%20%1
540
21st to endNight
7%429%35%23%1
540
July1st to 10thNight
10%217%33%32%6%
525
11th to 20thNight
9%323%33%28%4
522
21st to endNight
11%220%34%30%2
591
August1st to 10thNight
10%116%37%32%4
537
11th to 20thNight
9%315%37%32%4
534
21st to endNight
7%221%32%34%5%
594
September1st to 10thNight
16%317%33%27%4
550
11th to 20thNight
10%419%30%33%4
720
21st to endNight
14%7%22%29%25%3
720
October1st to 10thNight
12%7%27%31%19%5%
720
11th to 20thNight
21%12%30%24%12%1
720
21st to endNight
24%13%34%23%6%1
792
November1st to 10thNight
16%12%34%25%11%1
740
11th to 20thNight
19%18%29%26%7%1
760
21st to endNight
27%14%28%25%7%
760
December1st to 10thNight
25%15%36%20%5%
760
11th to 20thNight
27%14%29%23%6%
916
21st to endNight
32%15%29%19%4
1045
Page generated at 2024-01-28 05:26:31. Version ac07

Copyright 2024 Attilla Danko


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