Cleveland
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cleveland 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
32%
23436
13%
74847
9%
23384
38%
23384
16%
54837

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
9%
758
9%
2459
3%
757
15%
757
6%
2051
January11th to 20thNight
11%
760
5%
2470
3%
760
15%
760
6%
2116
January21st to endNight
14%
835
7%
2711
3%
835
19%
835
7%
2313
February1st to 10thNight
15%
720
6%
2340
3%
720
20%
720
7%
1943
February11th to 20thNight
16%
701
9%
2218
5%
700
22%
700
9%
1793
February21st to endNight
15%
592
11%
1776
2%
592
24%
592
11%
1406
March1st to 10thNight
22%
720
15%
2038
8%
720
29%
720
15%
1536
March11th to 20thNight
28%
720
17%
1980
10%
720
35%
720
19%
1428
March21st to endNight
29%
792
16%
2178
9%
792
34%
792
17%
1638
April1st to 10thNight
29%
720
12%
1949
5%
720
34%
720
19%
1434
April11th to 20thNight
29%
564
18%
1628
8%
564
37%
564
22%
1129
April21st to endNight
33%
540
18%
1620
8%
540
40%
540
23%
1085
May1st to 10thNight
37%
540
11%
1620
8%
540
39%
540
19%
1150
May11th to 20thNight
43%
531
16%
1592
11%
531
47%
531
22%
1086
May21st to endNight
54%
546
15%
1709
13%
546
58%
546
30%
1028
June1st to 10thNight
50%
360
15%
1440
16%
360
58%
360
22%
858
June11th to 20thNight
50%
360
17%
1430
18%
360
58%
360
22%
833
June21st to endNight
53%
361
21%
1261
20%
361
61%
361
27%
749
July1st to 10thNight
63%
525
16%
1481
15%
525
65%
525
34%
902
July11th to 20thNight
58%
522
18%
1566
15%
522
62%
522
35%
920
July21st to endNight
58%
591
18%
1672
15%
558
61%
558
29%
1056
August1st to 10thNight
64%
537
19%
1600
17%
534
65%
534
34%
944
August11th to 20thNight
59%
534
21%
1598
17%
534
62%
534
29%
1000
August21st to endNight
57%
605
22%
1793
16%
605
61%
605
31%
1096
September1st to 10thNight
56%
720
19%
1898
12%
720
59%
720
29%
1279
September11th to 20thNight
60%
720
26%
1980
18%
720
65%
720
33%
1235
September21st to endNight
43%
720
21%
1980
16%
720
48%
720
25%
1354
October1st to 10thNight
45%
720
19%
2094
15%
720
49%
720
25%
1375
October11th to 20thNight
27%
720
15%
2160
10%
720
35%
720
17%
1566
October21st to endNight
22%
792
15%
2394
9%
792
29%
792
13%
1837
November1st to 10thNight
30%
740
16%
2406
13%
740
36%
740
18%
1671
November11th to 20thNight
18%
760
13%
2493
8%
760
26%
760
10%
1942
November21st to endNight
17%
760
10%
2660
6%
760
22%
760
9%
2127
December1st to 10thNight
13%
760
5%
2660
3%
760
16%
760
6%
2243
December11th to 20thNight
12%
760
6%
3267
2%
759
19%
759
5%
2636
December21st to endNight
12%
830
4%
4726
2%
817
17%
817
3%
4078

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
16%11%47%6%35%5%5%7%31%
75023
Night
17%12%5%7%6%3445%6%30%
75088
TransparencyDay
52%5%12%19%11%1
74744
Night
55%5%10%18%10%1
74887
SeeingDay
22%11%28%24%12%4
13765
Night
24%11%25%26%12%2
23448

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%18%8%12%7%44445%15%
1706
11th to 20thDay
19%20%9%13%8%5%443312%
1710
21st to endDay
19%18%9%15%8%34445%11%
1872
February1st to 10thDay
18%17%7%10%10%34445%18%
1620
11th to 20thDay
15%14%7%13%10%35%445%18%
1627
21st to endDay
19%13%5%12%7%445%46%22%
1480
March1st to 10thDay
19%13%6%7%6%24446%27%
1921
11th to 20thDay
17%12%5%9%6%34445%31%
1980
21st to endDay
22%12%49%6%34346%27%
2178
April1st to 10thDay
16%13%46%5%3445%8%33%
2011
11th to 20thDay
19%10%35%5%35%45%7%34%
2297
21st to endDay
21%10%46%5%34446%34%
2340
May1st to 10thDay
17%9%36%7%36%45%7%33%
2340
11th to 20thDay
18%8%35%5%345%6%8%35%
2301
21st to endDay
10%6%35%6%46%6%6%9%39%
2562
June1st to 10thDay
15%6%25%5%46%5%6%8%39%
2520
11th to 20thDay
13%5%26%6%35%5%6%9%40%
2520
21st to endDay
11%5%345%35%5%7%9%42%
2693
July1st to 10thDay
9%426%5%35%5%5%10%45%
2426
11th to 20thDay
11%5%24435%5%7%11%43%
2340
21st to endDay
10%5%25%5%35%5%7%11%41%
2547
August1st to 10thDay
9%6%25%5%35%6%6%10%42%
2327
11th to 20thDay
10%6%26%6%36%7%8%8%38%
2303
21st to endDay
12%5%25%5%45%5%6%10%40%
2544
September1st to 10thDay
15%6%25%5%35%5%5%8%41%
2058
11th to 20thDay
13%5%345%35%5%5%9%43%
1980
21st to endDay
19%7%35%5%2445%7%38%
1980
October1st to 10thDay
16%7%36%5%35%6%5%6%38%
1865
11th to 20thDay
21%10%36%6%3445%7%31%
1800
21st to endDay
26%10%47%6%345%5%6%24%
1961
November1st to 10thDay
15%13%48%43445%7%34%
1672
11th to 20thDay
19%19%5%6%5%2435%5%26%
1685
21st to endDay
21%19%6%8%6%446%46%17%
1520
December1st to 10thDay
19%22%9%10%7%34435%14%
1520
11th to 20thDay
19%19%9%13%6%345%46%13%
1910
21st to endDay
24%22%8%11%8%343449%
2907
January1st to 10thNight
20%19%9%12%6%3333417%
2459
11th to 20thNight
20%21%8%12%8%4333414%
2470
21st to endNight
19%20%7%12%8%4434315%
2711
February1st to 10thNight
20%17%7%11%7%3444418%
2340
11th to 20thNight
19%16%7%11%7%4445%5%20%
2216
21st to endNight
21%14%6%11%6%3445%5%22%
1776
March1st to 10thNight
18%12%6%7%6%35%446%29%
2038
11th to 20thNight
17%12%46%435%5%5%6%34%
1980
21st to endNight
20%13%5%8%5%33445%30%
2178
April1st to 10thNight
17%13%5%6%5%25%5%5%6%32%
1949
11th to 20thNight
17%9%36%5%26%45%7%34%
1628
21st to endNight
16%9%45%5%3446%8%36%
1620
May1st to 10thNight
20%9%45%6%35%5%6%7%31%
1620
11th to 20thNight
16%8%46%5%35%45%8%35%
1592
21st to endNight
11%425%5%35%6%7%10%42%
1708
June1st to 10thNight
10%6%36%5%36%5%7%8%42%
1440
11th to 20thNight
10%5%25%7%36%5%6%9%41%
1430
21st to endNight
10%5%26%6%35%5%6%10%42%
1261
July1st to 10thNight
10%5%24435%45%7%50%
1525
11th to 20thNight
10%4245%35%5%7%11%46%
1620
21st to endNight
9%5%35%6%45%5%6%8%43%
1771
August1st to 10thNight
8%426%435%6%7%10%47%
1611
11th to 20thNight
10%6%26%6%445%7%8%43%
1598
21st to endNight
11%5%35%6%35%6%5%8%45%
1793
September1st to 10thNight
12%6%35%5%45%5%5%7%42%
1898
11th to 20thNight
12%6%245%3445%7%48%
1980
21st to endNight
16%7%35%6%35%45%6%39%
1980
October1st to 10thNight
16%7%25%5%245%7%7%41%
2094
11th to 20thNight
23%9%36%5%3445%7%31%
2160
21st to endNight
29%11%37%5%3345%6%25%
2394
November1st to 10thNight
18%11%46%5%3445%7%33%
2406
11th to 20thNight
19%18%5%8%6%34445%24%
2493
21st to endNight
23%18%6%7%6%34445%20%
2660
December1st to 10thNight
21%22%8%9%6%33445%15%
2660
11th to 20thNight
18%22%6%10%6%24345%18%
3285
21st to endNight
24%22%7%9%7%3444410%
4744

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
73%49%10%3
1707
11th to 20thDay
77%410%7%2
1710
21st to endDay
76%47%10%4
1872
February1st to 10thDay
69%410%12%4
1620
11th to 20thDay
70%48%13%41
1636
21st to endDay
63%5%12%12%7%1
1480
March1st to 10thDay
58%312%20%6%
1921
11th to 20thDay
56%411%18%10%1
1980
21st to endDay
60%48%19%8%1
2178
April1st to 10thDay
50%413%19%13%1
2011
11th to 20thDay
50%411%19%13%2
2297
21st to endDay
52%411%21%9%3
2340
May1st to 10thDay
51%5%10%21%11%2
2340
11th to 20thDay
47%6%10%19%14%3
2305
21st to endDay
40%6%15%24%14%2
2562
June1st to 10thDay
43%6%11%25%14%1
2520
11th to 20thDay
40%6%17%22%13%3
2520
21st to endDay
37%5%13%25%16%3
2693
July1st to 10thDay
35%6%11%27%19%2
2361
11th to 20thDay
35%5%15%28%16%2
2271
21st to endDay
35%6%16%25%16%2
2405
August1st to 10thDay
37%5%16%29%14%1
2314
11th to 20thDay
40%6%16%25%11%2
2303
21st to endDay
38%6%14%23%16%3
2544
September1st to 10thDay
41%5%15%21%15%3
2058
11th to 20thDay
37%5%15%25%16%1
1980
21st to endDay
45%412%21%17%1
1980
October1st to 10thDay
44%7%11%23%14%1
1865
11th to 20thDay
53%5%11%20%10%1
1800
21st to endDay
60%5%12%13%9%1
1961
November1st to 10thDay
50%6%10%20%12%1
1672
11th to 20thDay
61%5%9%15%8%2
1685
21st to endDay
68%6%8%12%5%
1520
December1st to 10thDay
75%49%10%3
1520
11th to 20thDay
73%5%8%11%2
1906
21st to endDay
81%48%6%1
2907
January1st to 10thNight
72%47%12%5%
2459
11th to 20thNight
76%49%10%2
2470
21st to endNight
74%5%7%10%41
2711
February1st to 10thNight
70%5%9%12%4
2340
11th to 20thNight
68%47%15%6%
2218
21st to endNight
65%49%14%7%1
1776
March1st to 10thNight
57%5%8%21%9%
2038
11th to 20thNight
51%5%11%19%12%2
1980
21st to endNight
56%5%6%20%10%2
2178
April1st to 10thNight
54%410%18%12%2
1949
11th to 20thNight
49%412%18%15%3
1628
21st to endNight
45%5%12%20%14%3
1620
May1st to 10thNight
52%5%11%17%11%3
1620
11th to 20thNight
47%5%11%18%15%4
1593
21st to endNight
35%7%16%26%14%2
1709
June1st to 10thNight
40%6%10%26%15%3
1440
11th to 20thNight
39%5%14%21%18%2
1430
21st to endNight
36%7%13%27%16%2
1261
July1st to 10thNight
35%5%11%24%20%5%
1481
11th to 20thNight
32%6%14%26%20%3
1566
21st to endNight
37%7%13%22%18%3
1672
August1st to 10thNight
32%7%14%30%17%1
1600
11th to 20thNight
37%7%14%27%12%2
1598
21st to endNight
36%6%13%24%18%3
1793
September1st to 10thNight
40%7%11%24%14%4
1898
11th to 20thNight
34%7%13%25%20%1
1980
21st to endNight
45%5%9%21%18%1
1980
October1st to 10thNight
40%7%12%21%19%1
2094
11th to 20thNight
53%5%10%20%11%1
2160
21st to endNight
61%49%16%9%1
2394
November1st to 10thNight
50%6%11%19%12%2
2406
11th to 20thNight
62%6%8%15%7%2
2493
21st to endNight
67%5%9%14%4
2660
December1st to 10thNight
73%5%8%10%4
2660
11th to 20thNight
69%5%12%12%2
3288
21st to endNight
77%5%10%7%1
4744

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%35%10%6%1
270
11th to 20thDay
31%20%35%10%4
270
21st to endDay
27%23%30%16%31
294
February1st to 10thDay
28%20%39%11%2
240
11th to 20thDay
30%23%32%15%
240
21st to endDay
26%27%37%9%1
198
March1st to 10thDay
27%18%30%20%41
361
11th to 20thDay
27%16%32%19%6%1
420
21st to endDay
32%16%28%20%4
462
April1st to 10thDay
24%17%30%22%6%1
420
11th to 20thDay
26%13%29%19%10%2
412
21st to endDay
28%12%31%20%7%2
420
May1st to 10thDay
28%12%29%21%8%2
423
11th to 20thDay
22%10%29%24%13%3
447
21st to endDay
15%429%28%19%6%
485
June1st to 10thDay
17%335%28%13%4
450
11th to 20thDay
17%427%32%15%4
450
21st to endDay
13%7%31%31%15%3
629
July1st to 10thDay
12%225%33%21%9%
531
11th to 20thDay
17%223%31%20%7%
444
21st to endDay
10%328%33%19%6%
488
August1st to 10thDay
12%422%33%20%9%
446
11th to 20thDay
14%324%33%18%8%
439
21st to endDay
13%424%32%18%8%
495
September1st to 10thDay
18%423%28%21%6%
450
11th to 20thDay
15%318%31%22%11%
450
21st to endDay
23%8%26%22%14%7%
450
October1st to 10thDay
17%8%24%26%18%6%
450
11th to 20thDay
24%15%32%21%7%1
450
21st to endDay
35%12%28%20%5%
476
November1st to 10thDay
21%20%28%19%9%3
270
11th to 20thDay
32%21%27%12%7%1
257
21st to endDay
28%17%39%14%2
180
December1st to 10thDay
27%21%32%15%41
180
11th to 20thDay
26%26%33%13%3
180
21st to endDay
32%21%32%14%2
238
January1st to 10thNight
32%21%29%15%4
760
11th to 20thNight
34%17%28%17%4
760
21st to endNight
31%14%30%21%3
835
February1st to 10thNight
32%17%29%20%2
720
11th to 20thNight
28%15%32%21%3
703
21st to endNight
29%16%33%19%2
592
March1st to 10thNight
25%14%32%24%5%
720
11th to 20thNight
24%14%30%24%7%1
720
21st to endNight
26%10%28%26%10%1
792
April1st to 10thNight
23%12%28%29%6%1
720
11th to 20thNight
22%10%34%23%11%1
564
21st to endNight
21%9%31%30%8%1
540
May1st to 10thNight
23%8%23%32%12%2
540
11th to 20thNight
21%6%23%33%15%2
531
21st to endNight
15%222%33%25%3
548
June1st to 10thNight
12%426%40%16%2
360
11th to 20thNight
12%323%43%18%1
360
21st to endNight
10%5%23%39%22%1
361
July1st to 10thNight
12%113%38%30%4
525
11th to 20thNight
12%320%35%25%6%
522
21st to endNight
12%317%39%27%2
591
August1st to 10thNight
10%413%42%26%5%
537
11th to 20thNight
12%213%39%29%4
534
21st to endNight
13%418%32%27%6%
605
September1st to 10thNight
15%5%16%33%24%6%
720
11th to 20thNight
14%414%32%30%6%
720
21st to endNight
19%8%22%26%19%5%
720
October1st to 10thNight
21%8%21%28%18%4
720
11th to 20thNight
28%13%28%23%8%1
720
21st to endNight
36%12%25%22%5%
792
November1st to 10thNight
25%13%28%25%9%1
740
11th to 20thNight
31%19%27%17%5%1
760
21st to endNight
34%16%29%16%5%
760
December1st to 10thNight
34%18%28%15%5%
760
11th to 20thNight
31%22%29%15%3
760
21st to endNight
34%15%31%18%2
836
Page generated at 2024-01-28 05:26:32. Version ac07

Copyright 2024 Attilla Danko


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