Marion
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marion clear sky chart from 2005-11-06 to 2024-01-22.

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%
24320
22%
74719
15%
24264
49%
24264
26%
47017

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
24%
950
19%
2648
8%
946
34%
946
20%
1819
January11th to 20thNight
18%
950
18%
2602
7%
950
27%
950
18%
1892
January21st to endNight
20%
1000
19%
2600
6%
1000
29%
1000
23%
1822
February1st to 10thNight
20%
785
17%
2225
6%
785
28%
785
17%
1630
February11th to 20thNight
20%
703
19%
2099
7%
700
30%
700
19%
1405
February21st to endNight
19%
592
18%
1776
6%
592
29%
592
17%
1242
March1st to 10thNight
24%
720
20%
2160
8%
720
34%
720
22%
1420
March11th to 20thNight
27%
637
17%
2077
9%
637
36%
637
19%
1394
March21st to endNight
31%
594
15%
1994
10%
594
38%
594
17%
1374
April1st to 10thNight
32%
540
24%
1800
14%
540
46%
540
27%
1051
April11th to 20thNight
38%
533
24%
1775
18%
533
50%
533
26%
1075
April21st to endNight
34%
540
19%
1800
12%
540
44%
540
23%
1164
May1st to 10thNight
41%
540
18%
1679
11%
540
48%
540
25%
1063
May11th to 20thNight
46%
531
18%
1593
13%
531
50%
531
24%
1059
May21st to endNight
60%
583
21%
1567
15%
582
63%
582
33%
1004
June1st to 10thNight
62%
540
21%
1440
16%
540
65%
540
38%
883
June11th to 20thNight
71%
540
28%
1440
21%
540
74%
540
45%
808
June21st to endNight
70%
540
25%
1440
18%
540
73%
540
46%
810
July1st to 10thNight
72%
525
20%
1400
17%
525
73%
525
40%
850
July11th to 20thNight
74%
522
23%
1392
20%
522
75%
522
42%
814
July21st to endNight
69%
591
26%
1529
22%
558
72%
558
40%
893
August1st to 10thNight
76%
537
21%
1734
24%
534
77%
534
39%
921
August11th to 20thNight
72%
534
26%
1776
30%
534
76%
534
35%
979
August21st to endNight
73%
594
25%
1980
29%
594
75%
594
37%
1061
September1st to 10thNight
65%
540
27%
1800
28%
540
67%
540
32%
1020
September11th to 20thNight
67%
616
32%
1876
29%
616
71%
616
37%
1065
September21st to endNight
59%
720
31%
1980
21%
720
65%
720
40%
1135
October1st to 10thNight
60%
720
31%
2034
24%
720
65%
720
42%
1118
October11th to 20thNight
42%
720
31%
2160
18%
720
55%
720
34%
1248
October21st to endNight
33%
792
25%
2462
16%
792
45%
792
26%
1542
November1st to 10thNight
42%
740
30%
2406
21%
740
54%
740
36%
1267
November11th to 20thNight
37%
760
29%
2470
17%
760
52%
760
29%
1421
November21st to endNight
32%
760
24%
2470
16%
760
43%
760
24%
1527
December1st to 10thNight
27%
845
19%
2555
10%
845
37%
845
21%
1709
December11th to 20thNight
30%
948
21%
3159
10%
948
39%
948
20%
2058
December21st to endNight
19%
1038
12%
4821
6%
1026
31%
1026
11%
3474

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
13%7%35%5%35%5%5%8%42%
74866
Night
13%7%35%5%3445%7%45%
75088
TransparencyDay
41%5%11%24%16%3
74570
Night
40%5%10%24%18%4
74905
SeeingDay
16%9%24%25%18%8%
14386
Night
17%9%26%30%16%2
24330

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
16%10%49%5%34445%36%
1517
11th to 20thDay
19%8%47%5%35%46%7%33%
1577
21st to endDay
11%11%5%8%7%34445%38%
1791
February1st to 10thDay
16%11%5%7%4245%45%37%
1732
11th to 20thDay
17%9%5%7%5%35%35%6%35%
1748
21st to endDay
16%10%46%5%44446%36%
1480
March1st to 10thDay
16%8%36%5%44446%41%
1800
11th to 20thDay
19%11%46%5%35%436%35%
1898
21st to endDay
19%9%47%6%35%45%6%33%
2360
April1st to 10thDay
10%6%35%5%35%46%9%46%
2160
11th to 20thDay
16%8%36%436%45%6%40%
2134
21st to endDay
19%6%35%4345%46%40%
2160
May1st to 10thDay
17%6%25%6%35%6%5%8%37%
2281
11th to 20thDay
16%6%25%5%345%6%8%40%
2301
21st to endDay
10%6%36%7%46%6%8%9%37%
2707
June1st to 10thDay
9%425%5%35%5%6%9%47%
2520
11th to 20thDay
6%3146%35%6%5%10%50%
2520
21st to endDay
6%4245%35%5%7%11%46%
2520
July1st to 10thDay
10%4245%46%5%7%12%40%
2520
11th to 20thDay
5%324445%6%7%11%49%
2520
21st to endDay
8%325%5%5%5%6%7%9%45%
2695
August1st to 10thDay
7%425%446%5%7%10%46%
2191
11th to 20thDay
10%425%6%45%6%7%10%42%
2125
21st to endDay
8%4245%35%5%6%10%48%
2376
September1st to 10thDay
12%5%25%5%34448%47%
2160
11th to 20thDay
8%6%25%5%35%6%5%7%49%
2066
21st to endDay
10%42432445%7%55%
1980
October1st to 10thDay
10%32442345%6%58%
1922
11th to 20thDay
13%5%25%42435%7%51%
1800
21st to endDay
19%7%34423445%46%
1892
November1st to 10thDay
9%5%3443445%6%54%
1672
11th to 20thDay
14%7%35%5%33446%46%
1710
21st to endDay
18%10%24433346%42%
1710
December1st to 10thDay
15%10%35%5%3445%7%39%
1620
11th to 20thDay
14%10%46%6%45%5%5%5%36%
1918
21st to endDay
21%15%47%5%24345%29%
2783
January1st to 10thNight
16%9%37%5%34446%38%
2648
11th to 20thNight
18%10%47%5%33445%35%
2602
21st to endNight
15%8%47%6%35%35%6%37%
2600
February1st to 10thNight
19%12%5%7%6%33335%33%
2225
11th to 20thNight
16%7%37%6%3445%5%41%
2098
21st to endNight
19%9%47%434445%37%
1776
March1st to 10thNight
16%7%26%5%345%45%43%
2160
11th to 20thNight
18%7%46%5%34445%40%
2077
21st to endNight
19%7%36%6%445%5%6%35%
1994
April1st to 10thNight
12%435%5%3445%7%49%
1800
11th to 20thNight
15%6%245%335%5%6%45%
1775
21st to endNight
19%5%35%5%245%6%6%39%
1800
May1st to 10thNight
16%5%35%5%335%47%44%
1679
11th to 20thNight
13%6%25%7%346%5%7%42%
1592
21st to endNight
7%336%7%45%5%6%10%44%
1567
June1st to 10thNight
10%425%435%5%5%9%48%
1440
11th to 20thNight
5%3234245%6%10%55%
1440
21st to endNight
42135%345%7%12%53%
1440
July1st to 10thNight
7%424435%5%7%9%51%
1440
11th to 20thNight
6%3245%3446%9%54%
1440
21st to endNight
6%3245%35%5%7%10%48%
1619
August1st to 10thNight
6%314425%5%7%10%53%
1744
11th to 20thNight
8%4245%345%5%8%53%
1776
21st to endNight
6%425%42446%9%53%
1980
September1st to 10thNight
11%5%25%5%33446%53%
1800
11th to 20thNight
8%426%43346%8%52%
1876
21st to endNight
10%413424447%56%
1980
October1st to 10thNight
8%424433446%58%
2034
11th to 20thNight
14%5%15%423336%54%
2160
21st to endNight
19%7%35%42234447%
2462
November1st to 10thNight
11%42432245%6%57%
2406
11th to 20thNight
13%5%25%424346%51%
2470
21st to endNight
17%7%36%424336%47%
2470
December1st to 10thNight
17%9%36%42445%6%39%
2555
11th to 20thNight
16%8%45%4345%5%5%42%
3279
21st to endNight
17%14%5%8%7%44446%28%
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
52%38%24%11%3
1518
11th to 20thDay
51%5%11%23%11%1
1577
21st to endDay
50%410%25%10%2
1791
February1st to 10thDay
50%5%10%22%12%1
1732
11th to 20thDay
50%49%20%13%3
1758
21st to endDay
50%410%20%12%4
1480
March1st to 10thDay
47%47%24%16%3
1800
11th to 20thDay
54%410%19%11%2
1898
21st to endDay
53%413%20%9%1
2360
April1st to 10thDay
36%413%28%17%1
2160
11th to 20thDay
44%410%22%16%3
2134
21st to endDay
45%5%11%26%12%2
2160
May1st to 10thDay
46%6%12%25%9%1
2281
11th to 20thDay
43%7%14%21%15%1
2305
21st to endDay
41%9%15%21%12%2
2707
June1st to 10thDay
33%7%13%26%18%2
2520
11th to 20thDay
29%7%11%28%21%3
2520
21st to endDay
31%7%16%23%18%5%
2520
July1st to 10thDay
36%8%15%24%14%4
2451
11th to 20thDay
28%8%15%28%17%4
2445
21st to endDay
34%8%13%30%13%2
2545
August1st to 10thDay
34%7%14%28%15%1
2177
11th to 20thDay
35%8%14%27%15%2
2125
21st to endDay
31%7%14%25%18%5%
2376
September1st to 10thDay
37%49%27%18%4
2160
11th to 20thDay
33%5%9%25%25%2
2066
21st to endDay
29%5%8%26%28%4
1980
October1st to 10thDay
28%49%27%27%5%
1922
11th to 20thDay
35%48%25%20%7%
1800
21st to endDay
42%47%26%19%4
1892
November1st to 10thDay
33%5%9%28%20%6%
1672
11th to 20thDay
40%47%23%21%5%
1710
21st to endDay
46%38%24%17%2
1710
December1st to 10thDay
46%410%25%13%1
1620
11th to 20thDay
51%38%24%12%2
1915
21st to endDay
58%411%16%10%1
2783
January1st to 10thNight
48%49%23%16%1
2648
11th to 20thNight
52%48%22%12%1
2602
21st to endNight
47%412%22%13%2
2600
February1st to 10thNight
56%38%21%11%1
2225
11th to 20thNight
46%47%22%17%3
2099
21st to endNight
50%5%9%19%13%4
1776
March1st to 10thNight
45%48%20%20%4
2160
11th to 20thNight
48%5%11%19%14%4
2077
21st to endNight
51%5%11%21%10%2
1994
April1st to 10thNight
35%5%11%27%19%3
1800
11th to 20thNight
39%410%22%19%5%
1775
21st to endNight
44%5%9%24%15%3
1800
May1st to 10thNight
40%6%11%26%14%2
1679
11th to 20thNight
42%7%11%21%16%2
1593
21st to endNight
36%7%16%23%15%4
1568
June1st to 10thNight
33%5%13%24%23%3
1440
11th to 20thNight
24%6%13%27%24%6%
1440
21st to endNight
23%6%18%27%18%7%
1440
July1st to 10thNight
30%6%16%26%17%6%
1400
11th to 20thNight
28%6%14%28%17%7%
1392
21st to endNight
27%8%14%31%19%2
1529
August1st to 10thNight
26%6%19%28%19%1
1734
11th to 20thNight
29%6%12%28%22%3
1776
21st to endNight
27%6%15%26%20%6%
1980
September1st to 10thNight
33%5%8%28%19%7%
1800
11th to 20thNight
30%5%8%29%23%5%
1876
21st to endNight
29%49%24%27%6%
1980
October1st to 10thNight
27%49%24%30%6%
2034
11th to 20thNight
33%36%24%27%7%
2160
21st to endNight
42%37%25%18%6%
2462
November1st to 10thNight
29%311%26%26%6%
2406
11th to 20thNight
35%47%24%23%7%
2470
21st to endNight
42%37%24%22%2
2470
December1st to 10thNight
47%411%23%14%2
2555
11th to 20thNight
45%48%23%17%2
3281
21st to endNight
57%410%16%10%2
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
26%14%33%22%41
270
11th to 20thDay
27%19%36%14%4
270
21st to endDay
21%21%40%14%4
267
February1st to 10thDay
27%16%43%9%5%
240
11th to 20thDay
30%19%37%11%2
240
21st to endDay
28%21%31%15%41
198
March1st to 10thDay
21%16%44%16%3
240
11th to 20thDay
30%18%34%15%4
240
21st to endDay
28%15%30%20%7%1
446
April1st to 10thDay
16%18%33%25%7%1
420
11th to 20thDay
23%15%25%24%12%
412
21st to endDay
23%12%31%22%10%2
420
May1st to 10thDay
20%11%33%24%10%3
423
11th to 20thDay
20%8%24%26%16%6%
447
21st to endDay
11%5%24%30%21%9%
661
June1st to 10thDay
11%418%26%26%15%
630
11th to 20thDay
6%320%34%28%9%
630
21st to endDay
7%423%34%22%10%
630
July1st to 10thDay
11%310%29%26%22%
621
11th to 20thDay
7%215%30%30%16%
618
21st to endDay
8%213%31%32%14%
684
August1st to 10thDay
8%212%30%32%16%
489
11th to 20thDay
14%313%27%30%12%
439
21st to endDay
9%210%26%33%18%
495
September1st to 10thDay
12%310%28%31%15%
450
11th to 20thDay
9%29%28%35%17%
450
21st to endDay
12%7%20%25%24%12%
450
October1st to 10thDay
10%5%22%35%21%7%
392
11th to 20thDay
19%10%36%24%9%2
270
21st to endDay
29%11%29%23%8%
297
November1st to 10thDay
14%9%33%26%14%4
270
11th to 20thDay
16%18%29%27%9%1
270
21st to endDay
28%11%29%23%7%1
270
December1st to 10thDay
18%13%40%15%10%3
270
11th to 20thDay
23%14%36%21%6%
270
21st to endDay
27%18%38%14%21
297
January1st to 10thNight
23%18%31%24%3
950
11th to 20thNight
25%19%33%18%4
950
21st to endNight
20%15%40%24%2
1000
February1st to 10thNight
26%16%33%23%2
785
11th to 20thNight
23%18%35%22%2
703
21st to endNight
26%17%35%21%2
592
March1st to 10thNight
22%15%35%24%4
720
11th to 20thNight
23%12%33%25%7%
637
21st to endNight
24%11%28%29%7%1
594
April1st to 10thNight
15%12%36%29%7%
540
11th to 20thNight
20%10%28%27%14%1
533
21st to endNight
23%7%30%30%9%1
540
May1st to 10thNight
19%5%28%35%12%1
540
11th to 20thNight
16%5%24%34%19%2
531
21st to endNight
9%320%42%24%3
584
June1st to 10thNight
12%215%37%30%4
540
11th to 20thNight
6%113%48%29%2
540
21st to endNight
4218%44%30%3
540
July1st to 10thNight
9%18%32%40%10%
525
11th to 20thNight
5%310%39%36%7%
522
21st to endNight
7%112%37%36%6%
591
August1st to 10thNight
6%47%37%41%5%
537
11th to 20thNight
9%28%39%37%5%
534
21st to endNight
7%27%35%40%8%
594
September1st to 10thNight
11%311%31%37%7%
540
11th to 20thNight
9%312%30%41%6%
616
21st to endNight
12%5%19%34%24%6%
720
October1st to 10thNight
10%5%18%38%24%5%
720
11th to 20thNight
17%6%29%30%16%2
720
21st to endNight
24%8%31%27%9%1
792
November1st to 10thNight
14%6%34%35%11%1
740
11th to 20thNight
16%12%30%31%10%
760
21st to endNight
22%11%31%25%10%
760
December1st to 10thNight
23%12%33%27%5%1
845
11th to 20thNight
23%10%33%27%6%1
950
21st to endNight
25%12%37%22%4
1045
Page generated at 2024-01-19 08:28:35. Version ac07

Copyright 2024 Attilla Danko


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