Buckeyestargazer Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Buckeyestargazer Observatory clear sky chart from 2005-11-05 to 2018-03-11.

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
37%
16692
17%
49070
11%
16650
43%
16650
22%
33369

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
19%
975
11%
2716
4%
970
25%
970
16%
2045
January16th to endNight
20%
1040
11%
2909
3%
1040
27%
1040
15%
2223
February1st to 15thNight
22%
804
12%
2335
4%
804
29%
804
16%
1687
February16th to endNight
23%
683
16%
2049
6%
683
32%
683
15%
1519
March1st to 15thNight
27%
764
13%
2292
8%
764
31%
764
18%
1651
March16th to endNight
30%
672
16%
2030
8%
672
38%
672
20%
1416
April1st to 15thNight
30%
539
14%
1797
9%
539
38%
539
19%
1225
April16th to endNight
32%
540
20%
1705
11%
540
42%
540
21%
1142
May1st to 15thNight
38%
540
15%
1620
9%
540
44%
540
20%
1143
May16th to endNight
51%
562
16%
1539
11%
561
55%
561
31%
1000
June1st to 15thNight
55%
540
16%
1440
11%
540
59%
540
36%
886
June16th to endNight
55%
540
16%
1440
10%
540
58%
540
31%
943
July1st to 15thNight
64%
510
17%
1360
14%
510
66%
510
39%
822
July16th to endNight
71%
564
22%
1417
17%
531
73%
531
41%
833
August1st to 15thNight
73%
539
21%
1585
21%
536
74%
536
39%
893
August16th to endNight
67%
573
21%
1910
21%
573
71%
573
33%
1091
September1st to 15thNight
63%
576
27%
1836
26%
576
66%
576
34%
1053
September16th to endNight
61%
717
29%
1980
22%
717
65%
717
37%
1172
October1st to 15thNight
50%
720
24%
2019
19%
720
54%
720
32%
1262
October16th to endNight
30%
768
19%
2472
12%
768
39%
768
20%
1620
November1st to 15thNight
32%
760
20%
2471
14%
760
41%
760
22%
1584
November16th to endNight
26%
780
17%
2535
10%
780
35%
780
17%
1748
December1st to 15thNight
21%
946
10%
2701
4%
946
27%
946
15%
2031
December16th to endNight
16%
1040
9%
2912
2%
1040
22%
1040
11%
2380

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%36%5%3445%7%35%
49561
Night
15%8%35%5%24446%38%
49238
Cloud CoverDay
14%8%36%5%3445%7%35%
49570
Night
15%8%35%5%2445%6%38%
49243
TransparencyDay
46%6%12%20%11%1
49247
Night
46%5%12%21%12%1
49070
SeeingDay
16%7%27%25%16%6%
6484
Night
18%8%28%29%13%1
16696

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
18%14%5%7%6%4435%6%22%
1552
16th to endDay
13%15%7%10%5%34445%23%
1664
February1st to 15thDay
15%14%5%8%6%34436%25%
1855
16th to endDay
16%11%5%9%6%24446%27%
1710
March1st to 15thDay
18%11%47%6%2445%6%28%
1895
16th to endDay
17%8%37%6%3445%7%30%
2204
April1st to 15thDay
19%9%36%424347%33%
2151
16th to endDay
19%7%245%2445%7%35%
2253
May1st to 15thDay
19%7%45%43445%7%32%
2331
16th to endDay
11%7%25%5%35%45%8%39%
2574
June1st to 15thDay
10%5%24445%5%5%8%44%
2520
16th to endDay
9%425%6%36%5%7%10%38%
2520
July1st to 15thDay
8%4245%35%5%6%9%43%
2520
16th to endDay
6%3245%35%6%8%9%42%
2655
August1st to 15thDay
6%425%5%346%6%9%45%
2362
16th to endDay
9%426%5%35%46%8%44%
2292
September1st to 15thDay
12%424435%5%6%7%43%
2112
16th to endDay
8%426%5%345%6%8%43%
1980
October1st to 15thDay
14%6%35%42445%6%40%
1938
16th to endDay
18%7%26%6%345%5%6%33%
1751
November1st to 15thDay
17%5%245%2445%6%40%
1717
16th to endDay
18%8%46%424347%33%
1755
December1st to 15thDay
18%13%5%8%6%34346%25%
1586
16th to endDay
20%16%5%8%5%34446%21%
1664
January1st to 15thNight
19%12%46%6%33445%29%
2716
16th to endNight
14%12%6%8%7%345%46%26%
2909
February1st to 15thNight
16%12%47%5%33346%32%
2333
16th to endNight
18%11%5%6%6%2434431%
2049
March1st to 15thNight
17%10%46%5%34446%33%
2279
16th to endNight
15%7%36%5%25%45%8%32%
2030
April1st to 15thNight
17%7%35%5%35%45%6%35%
1797
16th to endNight
17%7%25%6%14345%39%
1705
May1st to 15thNight
19%5%36%5%3445%5%35%
1620
16th to endNight
10%5%26%5%35%45%7%44%
1537
June1st to 15thNight
8%425%32345%8%48%
1440
16th to endNight
8%5%15%5%35%6%5%9%42%
1440
July1st to 15thNight
6%3135%245%5%8%52%
1440
16th to endNight
6%323426%46%10%49%
1513
August1st to 15thNight
5%4224245%5%10%51%
1594
16th to endNight
10%323425%45%7%51%
1910
September1st to 15thNight
12%414323446%52%
1836
16th to endNight
8%425%42445%8%50%
1980
October1st to 15thNight
12%7%15%423345%48%
2019
16th to endNight
19%7%25%42345%6%38%
2472
November1st to 15thNight
14%7%36%433446%40%
2471
16th to endNight
19%8%35%5%24447%33%
2535
December1st to 15thNight
19%11%5%7%5%24445%29%
2701
16th to endNight
22%14%5%7%6%35%44420%
2912

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%14%5%7%7%45%35%6%22%
1552
16th to endDay
14%15%6%10%6%35%446%22%
1664
February1st to 15thDay
15%14%5%8%6%34446%25%
1855
16th to endDay
16%11%5%9%5%2445%6%27%
1710
March1st to 15thDay
18%11%47%5%3445%6%28%
1905
16th to endDay
18%8%37%7%3445%7%30%
2203
April1st to 15thDay
19%8%35%423447%33%
2151
16th to endDay
19%7%3442445%7%35%
2253
May1st to 15thDay
19%8%36%43445%7%31%
2331
16th to endDay
11%6%35%6%35%45%8%39%
2574
June1st to 15thDay
10%5%25%5%35%5%5%7%43%
2520
16th to endDay
9%425%6%35%5%7%10%38%
2520
July1st to 15thDay
7%4245%45%5%6%9%43%
2520
16th to endDay
6%3245%46%6%8%9%42%
2655
August1st to 15thDay
6%415%5%25%6%6%9%44%
2362
16th to endDay
9%426%5%35%46%8%43%
2292
September1st to 15thDay
12%424335%5%6%7%43%
2112
16th to endDay
8%425%5%245%6%9%43%
1980
October1st to 15thDay
14%6%36%425%447%39%
1938
16th to endDay
18%7%36%6%35%5%5%6%33%
1751
November1st to 15thDay
17%5%25%5%2445%6%39%
1717
16th to endDay
18%9%46%434346%33%
1755
December1st to 15thDay
18%13%5%9%6%34446%25%
1586
16th to endDay
20%15%6%8%6%3345%5%20%
1664
January1st to 15thNight
19%12%46%5%34345%29%
2716
16th to endNight
14%12%6%8%8%245%5%6%26%
2909
February1st to 15thNight
16%11%5%6%5%33346%32%
2326
16th to endNight
18%12%47%5%34345%30%
2049
March1st to 15thNight
17%9%5%6%5%33445%33%
2292
16th to endNight
16%7%37%5%25%46%8%32%
2030
April1st to 15thNight
17%7%35%5%45%45%6%35%
1797
16th to endNight
18%7%25%6%24345%39%
1705
May1st to 15thNight
19%6%26%5%345%5%6%35%
1619
16th to endNight
10%5%26%5%3445%7%45%
1537
June1st to 15thNight
9%5%25%42345%8%48%
1440
16th to endNight
8%5%145%35%6%5%9%42%
1440
July1st to 15thNight
6%3135%245%48%53%
1440
16th to endNight
5%313435%46%10%49%
1513
August1st to 15thNight
5%4233245%5%10%51%
1594
16th to endNight
10%323325%45%6%51%
1910
September1st to 15thNight
11%41432245%6%52%
1836
16th to endNight
8%42442435%8%50%
1980
October1st to 15thNight
12%6%24423345%48%
2019
16th to endNight
19%7%25%32345%6%39%
2472
November1st to 15thNight
14%6%36%42445%6%40%
2471
16th to endNight
19%7%35%5%3445%7%33%
2535
December1st to 15thNight
19%11%5%7%5%34445%29%
2701
16th to endNight
22%14%5%7%7%35%44420%
2912

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
63%412%13%6%
1553
16th to endDay
61%5%13%14%4
1664
February1st to 15thDay
60%412%16%6%1
1857
16th to endDay
56%5%11%19%5%1
1710
March1st to 15thDay
56%6%11%18%7%
1905
16th to endDay
52%5%13%22%5%
2204
April1st to 15thDay
50%410%21%13%
2151
16th to endDay
47%6%13%18%11%4
2253
May1st to 15thDay
51%6%11%22%7%
2331
16th to endDay
42%6%11%22%15%2
2578
June1st to 15thDay
37%6%11%23%19%1
2520
16th to endDay
38%9%13%18%17%2
2520
July1st to 15thDay
36%6%13%22%16%3
2371
16th to endDay
34%8%17%22%13%2
2488
August1st to 15thDay
33%8%14%25%15%2
2347
16th to endDay
36%7%13%22%16%4
2292
September1st to 15thDay
37%6%10%22%17%4
2112
16th to endDay
35%6%11%25%19%1
1980
October1st to 15thDay
43%5%10%23%14%2
1938
16th to endDay
50%413%20%9%1
1751
November1st to 15thDay
44%5%12%21%13%2
1717
16th to endDay
52%312%23%7%
1755
December1st to 15thDay
61%311%17%5%
1586
16th to endDay
65%6%12%10%4
1664
January1st to 15thNight
56%412%16%8%
2716
16th to endNight
57%414%16%6%
2909
February1st to 15thNight
54%413%18%8%
2335
16th to endNight
55%5%10%20%8%
2049
March1st to 15thNight
52%5%11%19%9%2
2292
16th to endNight
48%6%14%20%8%1
2030
April1st to 15thNight
49%410%20%14%1
1797
16th to endNight
46%48%19%15%3
1705
May1st to 15thNight
49%6%10%22%11%
1620
16th to endNight
37%6%14%21%16%2
1539
June1st to 15thNight
33%5%13%26%19%1
1440
16th to endNight
36%8%14%21%17%2
1440
July1st to 15thNight
28%7%14%25%20%3
1360
16th to endNight
27%7%15%28%17%4
1417
August1st to 15thNight
26%7%16%26%21%2
1585
16th to endNight
31%6%12%24%20%5%
1910
September1st to 15thNight
31%6%10%25%20%5%
1836
16th to endNight
31%48%28%23%3
1980
October1st to 15thNight
37%410%27%20%
2019
16th to endNight
46%411%25%11%1
2472
November1st to 15thNight
44%410%23%14%3
2471
16th to endNight
50%414%23%7%
2535
December1st to 15thNight
57%412%18%6%
2701
16th to endNight
67%411%11%4
2912

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
26%8%34%20%9%
135
16th to endDay
24%11%40%20%2
144
February1st to 15thDay
23%15%45%15%
135
16th to endDay
30%11%35%13%10%
120
March1st to 15thDay
30%14%27%22%5%
121
16th to endDay
28%8%30%21%10%
273
April1st to 15thDay
25%8%32%23%8%1
270
16th to endDay
23%9%25%23%13%4
270
May1st to 15thDay
24%10%24%25%11%4
288
16th to endDay
15%7%31%24%17%4
474
June1st to 15thDay
11%427%32%19%4
495
16th to endDay
12%7%31%28%13%5%
495
July1st to 15thDay
10%426%29%18%12%
475
16th to endDay
7%320%32%23%12%
515
August1st to 15thDay
8%215%28%27%17%
347
16th to endDay
14%215%26%26%14%
332
September1st to 15thDay
14%214%29%27%10%
315
16th to endDay
9%5%14%28%31%10%
314
October1st to 15thDay
16%6%25%28%18%4
273
16th to endDay
22%11%35%24%6%
144
November1st to 15thDay
17%8%29%24%14%6%
135
16th to endDay
24%17%40%11%6%
135
December1st to 15thDay
18%18%40%16%5%
135
16th to endDay
24%20%46%6%1
144
January1st to 15thNight
24%13%36%20%4
975
16th to endNight
19%13%36%26%3
1040
February1st to 15thNight
22%11%36%25%3
807
16th to endNight
25%11%34%23%5%
683
March1st to 15thNight
23%9%35%23%7%
764
16th to endNight
19%8%36%26%8%
672
April1st to 15thNight
20%8%37%27%6%
539
16th to endNight
22%7%33%26%10%
540
May1st to 15thNight
22%428%32%10%
540
16th to endNight
12%326%38%19%
563
June1st to 15thNight
12%222%45%17%
540
16th to endNight
10%223%41%21%
540
July1st to 15thNight
7%218%42%26%2
510
16th to endNight
6%114%42%31%3
564
August1st to 15thNight
5%18%47%31%5%
539
16th to endNight
11%13%35%33%5%
573
September1st to 15thNight
14%312%35%29%4
576
16th to endNight
10%419%31%30%3
717
October1st to 15thNight
16%5%23%34%17%1
720
16th to endNight
23%11%31%25%8%
768
November1st to 15thNight
18%9%35%23%11%
760
16th to endNight
23%14%31%24%6%
780
December1st to 15thNight
25%14%31%23%4
946
16th to endNight
30%10%33%21%3
1040
Page generated at 2018-03-12 12:28:12. Version ac04

Copyright 2018 A. Danko


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