Berea
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Berea clear sky chart from 2005-11-05 to 2017-12-04.

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
43%
15742
20%
47881
14%
15698
49%
15698
24%
31477

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
18%
720
14%
2327
7%
716
27%
716
13%
1734
January16th to endNight
19%
768
17%
2496
8%
768
30%
768
16%
1756
February1st to 15thNight
19%
704
14%
2144
6%
701
28%
701
17%
1551
February16th to endNight
16%
631
15%
1893
6%
631
24%
631
14%
1401
March1st to 15thNight
26%
720
17%
2079
9%
720
33%
720
18%
1478
March16th to endNight
32%
768
15%
2112
9%
768
36%
768
21%
1518
April1st to 15thNight
35%
597
22%
1855
13%
597
47%
597
27%
1160
April16th to endNight
38%
540
21%
1656
11%
540
47%
540
25%
1076
May1st to 15thNight
39%
539
14%
1619
9%
539
44%
539
20%
1151
May16th to endNight
59%
562
18%
1684
14%
561
63%
561
28%
1082
June1st to 15thNight
69%
540
18%
1620
15%
540
72%
540
35%
955
June16th to endNight
67%
540
17%
1620
15%
540
68%
540
33%
957
July1st to 15thNight
64%
510
13%
1530
12%
510
65%
510
28%
976
July16th to endNight
72%
564
20%
1595
17%
531
75%
531
35%
949
August1st to 15thNight
73%
539
22%
1609
21%
536
74%
536
34%
961
August16th to endNight
75%
573
22%
1857
23%
573
75%
573
33%
1061
September1st to 15thNight
64%
678
23%
1938
20%
678
66%
678
31%
1217
September16th to endNight
62%
717
29%
1980
23%
717
65%
717
34%
1213
October1st to 15thNight
56%
720
30%
2016
25%
720
61%
720
37%
1200
October16th to endNight
42%
768
27%
2358
21%
768
52%
768
28%
1468
November1st to 15thNight
45%
760
27%
2471
22%
760
53%
760
30%
1455
November16th to endNight
35%
780
24%
2535
17%
780
45%
780
24%
1594
December1st to 15thNight
30%
736
15%
2391
10%
736
36%
736
16%
1722
December16th to endNight
23%
768
17%
2496
8%
768
34%
768
14%
1842

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
14%7%35%5%35%45%7%36%
48611
Night
13%7%35%5%2445%7%40%
48079
TransparencyDay
46%6%10%20%13%2
48312
Night
43%5%10%21%15%3
47882
SeeingDay
17%6%20%23%20%11%
5570
Night
18%7%24%28%18%2
15744

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 15thDay
18%11%5%10%5%2345%6%25%
1611
16th to endDay
17%12%46%5%15%345%32%
1728
February1st to 15thDay
16%11%6%8%5%34435%30%
1717
16th to endDay
15%11%48%5%46%346%29%
1580
March1st to 15thDay
22%9%35%5%23345%33%
1880
16th to endDay
18%9%46%425%347%32%
2111
April1st to 15thDay
14%7%25%5%3445%6%39%
2103
16th to endDay
15%6%35%43436%7%37%
2303
May1st to 15thDay
19%7%26%6%35%5%5%7%30%
2331
16th to endDay
10%6%36%6%45%45%8%38%
2431
June1st to 15thDay
8%425%6%46%6%6%8%38%
2340
16th to endDay
8%325%6%36%6%7%10%39%
2340
July1st to 15thDay
13%6%25%6%45%5%7%8%33%
2340
16th to endDay
11%425%6%47%7%7%10%32%
2465
August1st to 15thDay
10%5%25%5%37%5%7%9%35%
2340
16th to endDay
8%5%25%6%46%6%7%9%37%
2342
September1st to 15thDay
15%5%25%5%35%46%7%37%
2010
16th to endDay
14%435%424446%45%
1980
October1st to 15thDay
11%42443435%7%49%
1944
16th to endDay
19%5%13322345%47%
1864
November1st to 15thDay
14%7%24423446%46%
1717
16th to endDay
16%8%24323435%44%
1755
December1st to 15thDay
21%10%36%423345%32%
1651
16th to endDay
18%13%36%5%24446%29%
1728
January1st to 15thNight
18%11%5%9%5%3433428%
2327
16th to endNight
17%9%5%7%6%24435%33%
2496
February1st to 15thNight
15%11%49%5%24435%32%
2135
16th to endNight
17%12%48%7%33345%29%
1893
March1st to 15thNight
16%9%45%5%34445%35%
2079
16th to endNight
14%9%47%5%3445%6%34%
2112
April1st to 15thNight
12%7%2342345%6%45%
1855
16th to endNight
13%5%36%5%25%45%6%41%
1656
May1st to 15thNight
16%6%35%6%35%5%6%6%34%
1619
16th to endNight
8%3245%35%6%6%11%40%
1682
June1st to 15thNight
6%324435%5%8%11%45%
1620
16th to endNight
6%3145%25%5%8%12%42%
1620
July1st to 15thNight
8%425%5%45%5%5%8%42%
1620
16th to endNight
5%3145%35%6%8%11%45%
1703
August1st to 15thNight
6%315%5%3445%11%48%
1620
16th to endNight
5%3245%25%6%6%11%47%
1857
September1st to 15thNight
12%42442446%9%44%
1938
16th to endNight
9%5%34424346%49%
1980
October1st to 15thNight
12%42332345%7%51%
2016
16th to endNight
17%5%24324435%46%
2358
November1st to 15thNight
13%6%24413346%49%
2471
16th to endNight
17%8%24323345%43%
2535
December1st to 15thNight
20%11%45%423445%31%
2391
16th to endNight
21%10%47%424345%29%
2496

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
58%48%16%10%1
1612
16th to endDay
53%48%23%8%1
1728
February1st to 15thDay
56%5%7%21%8%1
1719
16th to endDay
55%410%18%8%1
1580
March1st to 15thDay
53%49%17%12%2
1880
16th to endDay
52%5%10%22%8%
2112
April1st to 15thDay
44%5%8%24%14%3
2103
16th to endDay
45%5%9%21%13%4
2303
May1st to 15thDay
52%6%10%18%10%1
2331
16th to endDay
42%8%13%22%11%2
2435
June1st to 15thDay
41%7%13%22%13%1
2340
16th to endDay
38%9%13%17%19%2
2340
July1st to 15thDay
46%8%12%15%14%2
2201
16th to endDay
42%10%13%19%11%2
2310
August1st to 15thDay
42%9%13%19%13%1
2327
16th to endDay
40%8%12%21%14%3
2342
September1st to 15thDay
45%6%10%17%15%4
2010
16th to endDay
39%410%20%23%2
1980
October1st to 15thDay
34%5%9%23%23%3
1944
16th to endDay
40%27%26%20%2
1864
November1st to 15thDay
39%37%23%20%5%
1717
16th to endDay
42%46%24%19%2
1755
December1st to 15thDay
54%5%8%19%9%2
1651
16th to endDay
56%5%11%19%7%
1728
January1st to 15thNight
59%37%14%12%1
2327
16th to endNight
53%39%21%10%1
2496
February1st to 15thNight
54%49%20%10%1
2144
16th to endNight
57%49%18%9%1
1893
March1st to 15thNight
51%48%19%13%2
2079
16th to endNight
50%5%10%22%9%
2112
April1st to 15thNight
38%49%22%20%4
1855
16th to endNight
42%5%10%22%14%5%
1656
May1st to 15thNight
48%7%11%19%10%2
1620
16th to endNight
37%9%13%23%13%2
1684
June1st to 15thNight
29%8%17%26%15%3
1620
16th to endNight
31%7%17%23%15%4
1620
July1st to 15thNight
37%7%14%21%15%3
1530
16th to endNight
28%9%17%24%15%3
1595
August1st to 15thNight
31%7%14%23%19%3
1609
16th to endNight
28%9%14%25%18%3
1857
September1st to 15thNight
36%6%12%20%17%5%
1938
16th to endNight
34%5%7%22%27%2
1980
October1st to 15thNight
31%5%9%24%23%5%
2016
16th to endNight
40%37%22%22%3
2358
November1st to 15thNight
37%36%23%23%5%
2471
16th to endNight
42%37%23%19%2
2535
December1st to 15thNight
55%49%18%10%2
2391
16th to endNight
57%49%17%9%1
2496

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
32%16%36%7%42
90
16th to endDay
29%20%38%9%2
96
February1st to 15thDay
24%22%40%8%4
90
16th to endDay
30%14%30%19%3
81
March1st to 15thDay
28%15%33%20%2
170
16th to endDay
22%10%32%23%9%1
288
April1st to 15thDay
18%14%25%25%14%2
270
16th to endDay
20%10%25%22%14%7%
270
May1st to 15thDay
23%9%25%23%10%7%
288
16th to endDay
16%321%28%18%11%
331
June1st to 15thDay
10%214%26%30%15%
315
16th to endDay
9%420%26%24%14%
315
July1st to 15thDay
20%312%25%20%17%
305
16th to endDay
12%18%20%29%26%
326
August1st to 15thDay
12%7%24%32%22%
313
16th to endDay
11%8%26%31%20%
332
September1st to 15thDay
18%39%19%28%20%
315
16th to endDay
14%211%22%32%17%
314
October1st to 15thDay
14%5%19%25%23%12%
315
16th to endDay
18%7%27%23%18%5%
280
November1st to 15thDay
21%6%27%22%19%2
135
16th to endDay
20%10%27%32%7%1
135
December1st to 15thDay
19%12%34%24%10%1
100
16th to endDay
23%19%43%10%2
96
January1st to 15thNight
26%17%33%17%4
720
16th to endNight
25%15%34%22%2
768
February1st to 15thNight
22%14%38%23%1
704
16th to endNight
26%14%39%17%2
631
March1st to 15thNight
22%13%32%25%5%
720
16th to endNight
20%9%31%27%10%
768
April1st to 15thNight
17%11%34%26%10%
597
16th to endNight
16%6%34%28%12%2
540
May1st to 15thNight
19%5%27%30%14%3
540
16th to endNight
10%218%34%28%5%
563
June1st to 15thNight
8%115%40%32%3
540
16th to endNight
6%117%38%32%3
540
July1st to 15thNight
12%11%35%36%3
510
16th to endNight
8%19%31%40%9%
564
August1st to 15thNight
8%6%35%39%8%
539
16th to endNight
6%18%36%39%7%
573
September1st to 15thNight
13%213%25%38%6%
678
16th to endNight
11%314%27%37%5%
717
October1st to 15thNight
13%420%28%26%5%
720
16th to endNight
21%5%27%26%17%2
768
November1st to 15thNight
18%6%26%27%18%2
760
16th to endNight
21%11%27%28%9%
780
December1st to 15thNight
29%11%24%27%7%
736
16th to endNight
28%12%31%23%3
768
Page generated at 2017-12-05 10:19:01. Version ac04

Copyright 2017 A. Danko


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