Cuyahoga Valley National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cuyahoga Valley National Park clear sky chart from 2005-11-05 to 2017-12-20.

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%
15585
15%
48175
10%
15546
40%
15546
19%
33783

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
11%
717
9%
2327
3%
716
17%
716
7%
1909
January16th to endNight
14%
768
10%
2496
4%
768
21%
768
8%
2009
February1st to 15thNight
15%
703
8%
2287
3%
701
22%
701
9%
1808
February16th to endNight
17%
631
11%
1916
4%
631
24%
631
11%
1500
March1st to 15thNight
23%
720
15%
2013
8%
720
30%
720
15%
1528
March16th to endNight
28%
768
16%
2112
11%
768
32%
768
20%
1505
April1st to 15thNight
23%
687
13%
1861
5%
687
28%
687
19%
1371
April16th to endNight
33%
540
21%
1620
9%
540
43%
540
25%
1059
May1st to 15thNight
37%
540
15%
1620
8%
540
43%
540
20%
1135
May16th to endNight
50%
546
16%
1669
14%
546
53%
546
30%
1028
June1st to 15thNight
48%
360
16%
1440
17%
360
57%
360
24%
827
June16th to endNight
51%
372
16%
1452
16%
372
59%
372
23%
853
July1st to 15thNight
60%
510
15%
1530
15%
510
63%
510
33%
947
July16th to endNight
63%
564
18%
1595
15%
531
67%
531
35%
929
August1st to 15thNight
64%
539
21%
1609
17%
536
67%
536
35%
944
August16th to endNight
63%
587
23%
1733
18%
587
66%
587
36%
1027
September1st to 15thNight
55%
720
24%
1923
15%
720
60%
720
35%
1193
September16th to endNight
55%
717
25%
1980
20%
717
59%
717
32%
1244
October1st to 15thNight
44%
720
20%
2118
17%
720
49%
720
26%
1373
October16th to endNight
25%
768
18%
2306
11%
768
35%
768
17%
1628
November1st to 15thNight
33%
760
19%
2471
14%
760
41%
760
22%
1618
November16th to endNight
20%
780
14%
2675
8%
780
28%
780
12%
1976
December1st to 15thNight
16%
780
8%
2730
4%
780
21%
780
8%
2152
December16th to endNight
13%
788
7%
2692
2%
788
18%
788
7%
2220

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%10%47%5%3445%6%30%
48643
Night
16%10%47%5%3445%6%32%
48368
Cloud CoverDay
16%10%47%5%3445%7%30%
48653
Night
16%10%47%5%3445%6%32%
48372
TransparencyDay
53%310%20%10%1
48354
Night
52%310%20%11%1
48175
SeeingDay
20%11%25%20%14%6%
5633
Night
21%11%26%26%13%1
15591

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
20%18%7%10%7%3433416%
1611
16th to endDay
17%19%9%12%9%245%4311%
1728
February1st to 15thDay
16%18%8%10%8%3434417%
1575
16th to endDay
16%14%6%11%8%3334422%
1557
March1st to 15thDay
21%14%7%8%5%32345%23%
1936
16th to endDay
19%11%6%6%5%34345%29%
2112
April1st to 15thDay
20%11%5%5%424346%30%
2096
16th to endDay
19%9%35%5%23436%35%
2340
May1st to 15thDay
19%8%36%5%35%5%5%7%29%
2331
16th to endDay
13%6%25%435%5%6%9%37%
2443
June1st to 15thDay
14%6%345%345%6%8%37%
2520
16th to endDay
14%425%5%36%5%6%10%35%
2504
July1st to 15thDay
12%5%36%6%45%5%5%7%36%
2340
16th to endDay
11%4245%46%6%6%9%37%
2465
August1st to 15thDay
9%5%26%5%46%7%7%8%35%
2340
16th to endDay
10%5%26%5%45%5%6%9%37%
2456
September1st to 15thDay
15%6%25%5%3445%8%37%
2034
16th to endDay
17%7%25%5%34346%39%
1980
October1st to 15thDay
19%7%26%5%2346%6%35%
1841
16th to endDay
25%7%27%5%23435%31%
1917
November1st to 15thDay
15%11%45%5%35%35%5%33%
1717
16th to endDay
20%17%48%6%34436%21%
1612
December1st to 15thDay
20%19%6%11%6%2433316%
1560
16th to endDay
21%20%9%11%6%2333412%
1628
January1st to 15thNight
22%16%7%11%7%3323317%
2327
16th to endNight
17%18%6%10%7%3434419%
2496
February1st to 15thNight
17%14%7%11%6%35%34421%
2285
16th to endNight
17%14%6%11%6%34445%22%
1916
March1st to 15thNight
20%12%6%7%424445%27%
2001
16th to endNight
15%10%46%6%3445%5%33%
2112
April1st to 15thNight
18%11%46%5%35%446%30%
1861
16th to endNight
11%7%25%5%35%45%7%38%
1620
May1st to 15thNight
17%7%46%5%35%45%7%31%
1620
16th to endNight
10%5%25%425%47%9%41%
1667
June1st to 15thNight
9%435%5%345%6%7%43%
1440
16th to endNight
11%3245%35%6%7%10%38%
1452
July1st to 15thNight
6%5%15%5%345%7%9%44%
1620
16th to endNight
7%5%25%43445%9%47%
1703
August1st to 15thNight
7%315%5%35%5%6%9%46%
1620
16th to endNight
10%4343345%5%7%47%
1733
September1st to 15thNight
12%5%2442345%7%47%
1923
16th to endNight
13%5%25%433447%44%
1980
October1st to 15thNight
15%5%25%5%34447%40%
2118
16th to endNight
23%7%36%5%3445%6%31%
2306
November1st to 15thNight
17%8%26%5%3445%5%37%
2471
16th to endNight
21%14%47%5%34445%24%
2675
December1st to 15thNight
21%16%6%9%5%34335%20%
2730
16th to endNight
22%18%8%8%5%34345%14%
2692

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%9%7%3433416%
1611
16th to endDay
17%19%9%12%8%335%4311%
1728
February1st to 15thDay
16%18%8%9%8%3434417%
1575
16th to endDay
16%14%7%10%8%4334422%
1557
March1st to 15thDay
21%14%6%8%5%32346%22%
1947
16th to endDay
19%11%5%6%5%34445%29%
2111
April1st to 15thDay
21%10%5%6%42435%6%29%
2096
16th to endDay
19%9%35%5%24436%35%
2340
May1st to 15thDay
19%8%36%5%35%5%5%7%29%
2331
16th to endDay
13%6%25%5%25%5%6%9%36%
2443
June1st to 15thDay
14%6%345%25%46%8%37%
2520
16th to endDay
14%4246%35%5%6%10%35%
2504
July1st to 15thDay
11%6%36%5%35%6%6%7%36%
2340
16th to endDay
11%4245%46%6%6%9%38%
2465
August1st to 15thDay
9%6%25%6%46%7%7%8%35%
2340
16th to endDay
10%5%26%5%45%5%7%9%36%
2456
September1st to 15thDay
15%6%25%435%45%8%38%
2034
16th to endDay
17%7%25%5%34346%39%
1980
October1st to 15thDay
19%7%26%5%2346%7%34%
1841
16th to endDay
26%6%27%5%24435%30%
1917
November1st to 15thDay
15%11%46%434445%33%
1717
16th to endDay
20%16%48%6%25%346%21%
1612
December1st to 15thDay
20%19%7%11%7%25%23316%
1560
16th to endDay
20%21%9%11%6%2333412%
1628
January1st to 15thNight
22%16%7%10%6%3323318%
2327
16th to endNight
17%18%6%9%7%3433419%
2496
February1st to 15thNight
17%14%6%11%6%4434421%
2278
16th to endNight
17%14%6%10%7%34435%22%
1916
March1st to 15thNight
20%11%6%7%424445%27%
2013
16th to endNight
15%10%46%6%24445%34%
2112
April1st to 15thNight
18%11%45%5%34446%30%
1861
16th to endNight
11%7%36%5%35%5%5%7%38%
1620
May1st to 15thNight
17%7%46%5%26%36%7%32%
1619
16th to endNight
10%5%245%245%7%9%41%
1667
June1st to 15thNight
9%425%6%35%5%6%7%43%
1440
16th to endNight
11%4245%36%5%7%9%39%
1452
July1st to 15thNight
6%5%25%5%345%6%8%45%
1620
16th to endNight
7%5%2443445%9%47%
1703
August1st to 15thNight
7%315%5%35%5%5%9%46%
1620
16th to endNight
10%425%4245%5%7%47%
1733
September1st to 15thNight
12%5%2442445%6%47%
1923
16th to endNight
13%4245%24447%44%
1980
October1st to 15thNight
16%5%15%6%2435%6%40%
2118
16th to endNight
23%7%25%5%3435%6%30%
2306
November1st to 15thNight
17%8%25%43445%5%37%
2471
16th to endNight
21%13%46%6%34445%24%
2675
December1st to 15thNight
21%17%6%9%5%3433420%
2730
16th to endNight
22%17%8%8%6%34345%14%
2692

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%28%10%4
1612
16th to endDay
75%210%9%2
1728
February1st to 15thDay
71%27%12%5%
1577
16th to endDay
64%210%15%5%
1557
March1st to 15thDay
62%310%17%5%
1947
16th to endDay
57%38%20%9%
2112
April1st to 15thDay
55%311%17%11%
2096
16th to endDay
51%210%19%12%3
2340
May1st to 15thDay
53%311%19%10%1
2331
16th to endDay
42%413%25%12%1
2447
June1st to 15thDay
43%311%27%13%1
2520
16th to endDay
41%5%13%22%15%1
2504
July1st to 15thDay
46%48%22%17%1
2201
16th to endDay
39%6%12%25%13%1
2310
August1st to 15thDay
43%5%10%27%12%1
2327
16th to endDay
41%411%24%13%3
2456
September1st to 15thDay
43%410%23%15%2
2034
16th to endDay
46%27%24%17%1
1980
October1st to 15thDay
47%39%22%15%
1841
16th to endDay
55%212%19%8%
1917
November1st to 15thDay
51%38%22%10%3
1717
16th to endDay
65%29%15%7%
1612
December1st to 15thDay
73%28%12%3
1560
16th to endDay
76%38%9%2
1628
January1st to 15thNight
71%27%13%5%
2327
16th to endNight
68%29%13%4
2496
February1st to 15thNight
66%39%14%5%
2287
16th to endNight
64%38%17%6%
1916
March1st to 15thNight
58%38%20%8%
2013
16th to endNight
52%311%21%9%2
2112
April1st to 15thNight
54%39%17%14%
1861
16th to endNight
44%311%19%17%4
1620
May1st to 15thNight
51%49%20%12%2
1620
16th to endNight
38%414%25%15%3
1669
June1st to 15thNight
38%411%26%16%1
1440
16th to endNight
38%6%14%22%16%2
1452
July1st to 15thNight
37%310%26%20%2
1530
16th to endNight
33%313%28%17%4
1595
August1st to 15thNight
33%411%30%18%1
1609
16th to endNight
33%412%26%19%4
1733
September1st to 15thNight
35%311%26%19%3
1923
16th to endNight
38%39%25%21%1
1980
October1st to 15thNight
42%311%22%19%1
2118
16th to endNight
53%29%24%9%
2306
November1st to 15thNight
47%211%20%13%4
2471
16th to endNight
60%29%18%7%
2675
December1st to 15thNight
67%210%13%5%
2730
16th to endNight
71%311%11%2
2692

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
27%30%25%10%5%1
90
16th to endDay
30%33%22%9%4
96
February1st to 15thDay
32%30%34%3
90
16th to endDay
24%25%43%6%
81
March1st to 15thDay
29%14%29%18%7%
237
16th to endDay
25%18%28%17%8%1
288
April1st to 15thDay
25%15%30%17%10%
270
16th to endDay
22%12%29%18%10%6%
270
May1st to 15thDay
26%12%28%18%11%3
288
16th to endDay
19%10%30%21%10%6%
331
June1st to 15thDay
15%8%27%30%12%4
315
16th to endDay
18%9%25%27%10%8%
315
July1st to 15thDay
16%225%26%20%8%
305
16th to endDay
10%320%27%26%11%
326
August1st to 15thDay
16%317%28%23%10%
313
16th to endDay
11%6%17%26%22%16%
332
September1st to 15thDay
19%5%19%19%22%14%
315
16th to endDay
20%6%13%18%28%13%
314
October1st to 15thDay
18%8%26%21%21%2
315
16th to endDay
27%14%30%21%41
333
November1st to 15thDay
28%15%18%23%14%
135
16th to endDay
24%29%36%5%2
102
December1st to 15thDay
25%31%27%7%43
90
16th to endDay
29%37%25%6%1
82
January1st to 15thNight
32%18%31%13%3
720
16th to endNight
27%20%29%19%2
768
February1st to 15thNight
25%20%31%19%3
704
16th to endNight
24%18%33%19%3
631
March1st to 15thNight
27%14%30%22%5%
720
16th to endNight
20%14%30%24%9%1
768
April1st to 15thNight
25%14%31%21%6%
687
16th to endNight
16%9%34%26%11%1
540
May1st to 15thNight
19%9%24%34%10%
540
16th to endNight
13%325%35%18%2
548
June1st to 15thNight
11%328%39%16%
360
16th to endNight
11%426%41%15%
372
July1st to 15thNight
9%19%42%25%2
510
16th to endNight
9%314%41%27%4
564
August1st to 15thNight
10%113%41%28%4
539
16th to endNight
11%116%33%34%3
587
September1st to 15thNight
13%417%30%28%5%
720
16th to endNight
15%417%28%27%6%
717
October1st to 15thNight
18%6%23%30%17%3
720
16th to endNight
25%13%29%22%8%
768
November1st to 15thNight
21%11%26%26%12%1
760
16th to endNight
29%19%25%16%8%
780
December1st to 15thNight
31%18%27%15%5%
780
16th to endNight
29%18%32%17%2
788
Page generated at 2017-12-21 07:04:52. Version ac04

Copyright 2017 A. Danko


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