Cleveland
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cleveland clear sky chart from 2005-11-05 to 2018-02-22.

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
34%
15803
13%
48819
10%
15765
38%
15765
16%
35684

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
10%
777
8%
2522
4%
776
14%
776
7%
2108
January16th to endNight
13%
832
7%
2704
3%
832
18%
832
7%
2269
February1st to 15thNight
17%
762
7%
2482
3%
761
21%
761
7%
2049
February16th to endNight
18%
659
10%
2000
4%
659
25%
659
10%
1615
March1st to 15thNight
25%
720
14%
2019
8%
720
30%
720
14%
1567
March16th to endNight
33%
768
16%
2112
11%
768
37%
768
20%
1538
April1st to 15thNight
29%
677
12%
1854
5%
677
34%
677
19%
1361
April16th to endNight
38%
540
20%
1620
9%
540
46%
540
25%
1056
May1st to 15thNight
41%
540
13%
1620
9%
540
45%
540
20%
1147
May16th to endNight
50%
537
15%
1660
13%
537
53%
537
27%
1048
June1st to 15thNight
53%
360
15%
1440
18%
360
59%
360
23%
852
June16th to endNight
54%
360
17%
1314
18%
360
60%
360
25%
778
July1st to 15thNight
61%
510
16%
1468
15%
510
64%
510
35%
882
July16th to endNight
63%
564
17%
1595
14%
531
67%
531
33%
966
August1st to 15thNight
66%
539
19%
1609
18%
536
66%
536
33%
959
August16th to endNight
60%
581
22%
1727
17%
581
63%
581
32%
1047
September1st to 15thNight
58%
720
20%
1926
13%
720
61%
720
29%
1283
September16th to endNight
52%
717
24%
1980
19%
717
56%
717
28%
1312
October1st to 15thNight
45%
720
17%
2117
16%
720
48%
720
23%
1424
October16th to endNight
23%
768
15%
2316
9%
768
31%
768
14%
1734
November1st to 15thNight
32%
760
16%
2471
13%
760
38%
760
16%
1769
November16th to endNight
18%
780
10%
2681
8%
780
23%
780
9%
2130
December1st to 15thNight
13%
780
5%
2730
3%
780
17%
780
6%
2295
December16th to endNight
11%
832
5%
2852
2%
832
15%
832
5%
2495

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%9%46%5%3445%7%31%
49400
Night
17%11%47%5%34446%30%
49011
Cloud CoverDay
16%10%46%5%3445%7%31%
49410
Night
17%11%47%5%34446%30%
49015
TransparencyDay
52%411%19%10%1
49111
Night
54%5%10%17%10%1
48819
SeeingDay
21%9%25%23%14%5%
5977
Night
23%10%24%26%13%2
15810

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
21%16%8%9%7%3433416%
1746
16th to endDay
18%16%8%13%8%44335%12%
1872
February1st to 15thDay
17%17%7%9%9%4443416%
1710
16th to endDay
16%14%5%11%8%2435%5%20%
1618
March1st to 15thDay
20%13%7%8%5%23435%24%
1930
16th to endDay
19%9%5%7%5%34346%30%
2112
April1st to 15thDay
19%10%3443435%7%31%
2104
16th to endDay
18%7%45%5%24445%37%
2340
May1st to 15thDay
17%8%27%5%36%5%5%6%32%
2331
16th to endDay
12%5%25%5%345%5%9%40%
2452
June1st to 15thDay
13%5%245%35%45%8%39%
2520
16th to endDay
12%425%5%25%5%6%9%39%
2635
July1st to 15thDay
10%425%5%25%5%6%9%42%
2397
16th to endDay
9%424435%5%7%11%41%
2465
August1st to 15thDay
7%5%25%5%35%5%7%10%40%
2340
16th to endDay
10%426%6%35%5%6%9%39%
2462
September1st to 15thDay
15%5%25%5%25%45%8%38%
2031
16th to endDay
16%6%245%235%46%39%
1980
October1st to 15thDay
18%6%26%5%2445%6%35%
1842
16th to endDay
25%7%36%5%24446%28%
1907
November1st to 15thDay
17%13%46%5%2445%6%31%
1717
16th to endDay
20%20%5%6%5%24446%19%
1608
December1st to 15thDay
21%19%9%10%5%3443413%
1560
16th to endDay
20%20%9%12%7%3433410%
1721
January1st to 15thNight
22%17%8%10%6%3332417%
2522
16th to endNight
18%18%6%10%9%3433416%
2704
February1st to 15thNight
19%15%7%10%6%3443419%
2480
16th to endNight
19%13%6%11%7%24435%20%
2000
March1st to 15thNight
19%12%5%8%5%25%445%26%
2007
16th to endNight
16%11%5%6%425%35%6%32%
2112
April1st to 15thNight
19%11%45%5%2435%6%31%
1854
16th to endNight
12%7%35%445%5%5%8%38%
1620
May1st to 15thNight
19%8%35%5%35%46%8%30%
1620
16th to endNight
11%5%25%5%345%6%9%39%
1658
June1st to 15thNight
9%435%5%35%5%5%7%43%
1440
16th to endNight
8%425%6%446%6%10%39%
1314
July1st to 15thNight
8%4244345%6%9%47%
1557
16th to endNight
8%4144345%6%9%45%
1703
August1st to 15thNight
7%325%5%246%5%10%45%
1620
16th to endNight
11%5%15%4245%5%7%46%
1727
September1st to 15thNight
13%5%245%25%5%5%7%43%
1926
16th to endNight
15%6%245%2445%6%41%
1980
October1st to 15thNight
17%6%35%5%2445%7%38%
2117
16th to endNight
26%7%36%5%3335%6%28%
2316
November1st to 15thNight
19%10%35%5%3345%5%31%
2471
16th to endNight
23%16%47%5%25%345%20%
2681
December1st to 15thNight
22%18%7%9%5%2333416%
2730
16th to endNight
23%19%7%8%7%3444411%
2852

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
21%17%7%10%7%4434415%
1746
16th to endDay
18%17%9%12%8%4433412%
1872
February1st to 15thDay
17%18%7%9%9%35%43415%
1710
16th to endDay
18%13%6%11%8%34345%21%
1618
March1st to 15thDay
21%13%6%8%5%23345%23%
1941
16th to endDay
19%9%47%5%34436%29%
2111
April1st to 15thDay
20%11%35%42435%7%30%
2104
16th to endDay
19%8%35%434345%37%
2340
May1st to 15thDay
18%8%35%5%36%45%6%32%
2331
16th to endDay
12%6%245%345%5%8%40%
2452
June1st to 15thDay
14%5%24435%45%8%39%
2520
16th to endDay
13%425%435%5%7%9%38%
2635
July1st to 15thDay
11%425%425%5%6%9%42%
2397
16th to endDay
10%414435%5%6%11%41%
2465
August1st to 15thDay
9%5%15%5%35%6%7%9%39%
2340
16th to endDay
11%425%5%45%5%7%9%40%
2462
September1st to 15thDay
16%6%245%2445%8%38%
2031
16th to endDay
17%6%25%5%24446%39%
1980
October1st to 15thDay
19%7%25%435%5%46%34%
1842
16th to endDay
26%8%36%5%23446%28%
1907
November1st to 15thDay
17%13%46%434445%31%
1717
16th to endDay
21%19%5%6%5%24436%19%
1608
December1st to 15thDay
20%21%9%10%6%2433313%
1560
16th to endDay
21%21%9%12%7%33225%10%
1721
January1st to 15thNight
22%18%7%10%6%3323417%
2522
16th to endNight
18%19%6%10%9%4433416%
2704
February1st to 15thNight
18%17%7%11%7%3434318%
2473
16th to endNight
19%14%6%10%7%34445%20%
2000
March1st to 15thNight
20%12%6%7%435%345%26%
2019
16th to endNight
16%11%5%6%434445%33%
2112
April1st to 15thNight
20%11%35%5%24445%31%
1854
16th to endNight
13%7%35%425%45%8%38%
1620
May1st to 15thNight
19%7%35%5%35%46%7%30%
1619
16th to endNight
12%425%5%25%5%6%8%40%
1658
June1st to 15thNight
9%5%25%5%36%45%8%42%
1440
16th to endNight
8%5%25%6%35%5%6%10%39%
1314
July1st to 15thNight
8%413425%45%8%48%
1557
16th to endNight
8%4234345%6%9%45%
1703
August1st to 15thNight
7%325%4246%7%10%45%
1620
16th to endNight
11%5%145%245%5%7%46%
1727
September1st to 15thNight
12%6%2443445%7%43%
1926
16th to endNight
15%6%245%35%35%6%41%
1980
October1st to 15thNight
17%6%3442346%6%39%
2117
16th to endNight
26%8%27%5%23346%27%
2316
November1st to 15thNight
20%10%35%5%2435%5%31%
2471
16th to endNight
23%16%48%5%24345%20%
2681
December1st to 15thNight
22%19%7%9%5%2344416%
2730
16th to endNight
23%19%7%8%8%3444411%
2852

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
72%48%9%4
1747
16th to endDay
75%39%8%2
1872
February1st to 15thDay
71%48%11%3
1712
16th to endDay
65%312%13%4
1618
March1st to 15thDay
62%412%15%5%
1941
16th to endDay
55%49%21%7%1
2112
April1st to 15thDay
53%412%17%11%
2104
16th to endDay
48%411%20%12%4
2340
May1st to 15thDay
50%5%10%21%10%2
2331
16th to endDay
40%5%13%24%13%2
2456
June1st to 15thDay
42%5%13%25%12%1
2520
16th to endDay
39%6%14%22%15%2
2635
July1st to 15thDay
37%5%10%26%18%1
2258
16th to endDay
35%416%26%14%1
2310
August1st to 15thDay
37%5%14%27%13%
2327
16th to endDay
39%5%14%23%14%3
2462
September1st to 15thDay
43%5%13%22%13%1
2031
16th to endDay
44%410%22%17%1
1980
October1st to 15thDay
48%6%10%20%13%1
1842
16th to endDay
56%413%16%8%
1907
November1st to 15thDay
54%49%18%10%2
1717
16th to endDay
66%49%12%6%
1608
December1st to 15thDay
76%37%9%2
1560
16th to endDay
79%47%6%1
1721
January1st to 15thNight
72%47%10%5%
2522
16th to endNight
72%49%10%2
2704
February1st to 15thNight
70%48%12%3
2482
16th to endNight
66%48%15%4
2000
March1st to 15thNight
60%5%8%17%7%
2019
16th to endNight
52%410%21%9%1
2112
April1st to 15thNight
54%310%17%12%
1854
16th to endNight
43%411%19%16%4
1620
May1st to 15thNight
50%5%11%18%11%2
1620
16th to endNight
39%6%13%23%14%2
1660
June1st to 15thNight
39%5%11%24%17%
1440
16th to endNight
37%6%14%22%15%2
1314
July1st to 15thNight
33%5%10%25%21%2
1468
16th to endNight
32%7%13%23%19%4
1595
August1st to 15thNight
31%8%13%28%17%1
1609
16th to endNight
35%5%12%25%17%3
1727
September1st to 15thNight
38%7%11%22%15%3
1926
16th to endNight
42%5%8%23%19%1
1980
October1st to 15thNight
44%6%11%18%18%
2117
16th to endNight
57%410%19%6%
2316
November1st to 15thNight
53%5%10%15%11%3
2471
16th to endNight
66%5%7%14%5%
2681
December1st to 15thNight
72%48%9%4
2730
16th to endNight
75%6%8%7%1
2852

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
20%22%35%11%8%1
135
16th to endDay
28%22%34%11%2
144
February1st to 15thDay
31%20%33%14%
135
16th to endDay
30%15%40%15%
100
March1st to 15thDay
28%14%27%21%7%
231
16th to endDay
26%15%26%20%8%1
288
April1st to 15thDay
27%12%27%25%6%1
270
16th to endDay
23%9%27%20%13%4
270
May1st to 15thDay
26%8%27%20%13%3
288
16th to endDay
18%6%27%27%13%6%
331
June1st to 15thDay
18%230%28%15%4
315
16th to endDay
15%7%28%30%14%3
435
July1st to 15thDay
15%228%31%15%7%
362
16th to endDay
11%122%28%23%11%
326
August1st to 15thDay
13%220%30%21%12%
313
16th to endDay
13%318%30%21%13%
332
September1st to 15thDay
18%219%23%26%10%
315
16th to endDay
21%5%16%20%21%14%
314
October1st to 15thDay
21%10%16%26%20%5%
315
16th to endDay
30%13%26%21%6%1
323
November1st to 15thDay
28%13%18%21%15%2
135
16th to endDay
31%17%36%12%4
100
December1st to 15thDay
18%31%30%13%42
90
16th to endDay
28%31%33%6%
110
January1st to 15thNight
32%18%29%15%3
780
16th to endNight
30%14%31%20%3
832
February1st to 15thNight
28%17%27%22%3
764
16th to endNight
26%13%32%22%4
659
March1st to 15thNight
26%13%29%24%6%
720
16th to endNight
21%10%27%27%11%1
768
April1st to 15thNight
24%12%26%27%7%
677
16th to endNight
16%8%31%29%12%1
540
May1st to 15thNight
23%7%18%34%14%1
540
16th to endNight
15%322%32%22%4
539
June1st to 15thNight
9%423%42%20%1
360
16th to endNight
9%323%42%20%
360
July1st to 15thNight
11%117%40%25%3
510
16th to endNight
10%216%37%28%3
564
August1st to 15thNight
9%211%43%27%5%
539
16th to endNight
13%313%31%31%5%
581
September1st to 15thNight
15%414%30%27%6%
720
16th to endNight
17%5%16%25%27%7%
717
October1st to 15thNight
22%7%19%27%19%3
720
16th to endNight
32%12%26%21%5%
768
November1st to 15thNight
26%11%25%25%9%1
760
16th to endNight
33%17%26%15%6%
780
December1st to 15thNight
32%20%26%15%5%
780
16th to endNight
34%16%29%16%2
832
Page generated at 2018-02-23 11:21:29. Version ac04

Copyright 2018 A. Danko


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