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 2017-03-13.

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%
15356
16%
45135
11%
15314
43%
15314
22%
30808

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%
900
11%
2506
4%
895
24%
895
15%
1905
January16th to endNight
21%
960
11%
2685
3%
960
27%
960
15%
2062
February1st to 15thNight
23%
741
11%
2152
3%
741
29%
741
16%
1547
February16th to endNight
24%
631
16%
1893
6%
631
33%
631
16%
1397
March1st to 15thNight
26%
712
13%
2136
8%
712
31%
712
17%
1556
March16th to endNight
31%
616
16%
1861
9%
616
38%
616
21%
1289
April1st to 15thNight
29%
494
15%
1647
10%
494
38%
494
20%
1114
April16th to endNight
32%
495
19%
1563
10%
495
41%
495
21%
1053
May1st to 15thNight
37%
495
16%
1485
9%
495
44%
495
20%
1056
May16th to endNight
52%
514
16%
1408
11%
513
57%
513
31%
911
June1st to 15thNight
52%
495
17%
1320
11%
495
57%
495
34%
831
June16th to endNight
56%
495
14%
1320
10%
495
58%
495
30%
876
July1st to 15thNight
64%
465
18%
1240
15%
465
65%
465
40%
746
July16th to endNight
71%
522
19%
1305
15%
489
72%
489
40%
777
August1st to 15thNight
73%
494
23%
1452
22%
491
74%
491
40%
815
August16th to endNight
67%
525
19%
1750
20%
525
71%
525
33%
1001
September1st to 15thNight
63%
528
28%
1683
27%
528
67%
528
34%
965
September16th to endNight
60%
657
27%
1815
20%
657
64%
657
36%
1087
October1st to 15thNight
51%
660
26%
1851
20%
660
56%
660
34%
1133
October16th to endNight
29%
704
17%
2266
11%
704
39%
704
20%
1501
November1st to 15thNight
32%
700
22%
2276
15%
700
42%
700
23%
1440
November16th to endNight
27%
720
15%
2340
10%
720
34%
720
15%
1636
December1st to 15thNight
21%
873
10%
2493
4%
873
26%
873
14%
1900
December16th to endNight
16%
960
9%
2688
2%
960
22%
960
10%
2210

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%8%36%5%35%45%7%35%
45552
Night
15%8%35%5%24446%37%
45303
Cloud CoverDay
14%8%36%5%35%45%7%35%
45561
Night
15%8%35%5%2445%6%37%
45308
TransparencyDay
47%6%12%20%11%1
45238
Night
46%5%12%21%12%1
45135
SeeingDay
16%6%25%26%17%6%
5119
Night
19%8%28%29%13%1
15360

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
17%14%5%8%7%45%35%6%20%
1432
16th to endDay
13%15%7%10%6%35%445%22%
1536
February1st to 15thDay
14%14%5%8%6%35%5%36%25%
1708
16th to endDay
15%10%5%9%6%25%45%6%28%
1580
March1st to 15thDay
19%11%47%5%2445%6%28%
1761
16th to endDay
16%8%27%6%3445%7%32%
2020
April1st to 15thDay
19%9%35%424347%33%
1971
16th to endDay
19%7%2442445%7%35%
2065
May1st to 15thDay
19%7%45%5%3445%7%30%
2136
16th to endDay
11%6%35%5%35%45%9%39%
2354
June1st to 15thDay
11%5%25%5%35%5%5%8%41%
2310
16th to endDay
9%425%6%36%5%7%10%38%
2310
July1st to 15thDay
8%4245%35%46%10%44%
2310
16th to endDay
6%3246%36%6%8%9%41%
2459
August1st to 15thDay
7%425%6%346%6%9%45%
2165
16th to endDay
10%426%5%3446%8%43%
2100
September1st to 15thDay
12%424335%5%6%7%43%
1936
16th to endDay
8%426%5%345%6%9%42%
1815
October1st to 15thDay
13%6%35%425%5%5%6%41%
1777
16th to endDay
19%7%26%6%345%5%6%32%
1605
November1st to 15thDay
16%6%2442445%6%42%
1582
16th to endDay
19%9%5%6%435%347%31%
1620
December1st to 15thDay
19%14%5%9%6%34346%23%
1464
16th to endDay
21%16%5%7%5%34445%20%
1536
January1st to 15thNight
19%12%46%6%34445%28%
2506
16th to endNight
14%12%6%8%7%345%46%26%
2685
February1st to 15thNight
16%11%5%7%5%34346%33%
2150
16th to endNight
17%11%5%6%6%34345%31%
1893
March1st to 15thNight
17%10%46%5%34445%32%
2123
16th to endNight
15%7%36%5%35%45%7%33%
1861
April1st to 15thNight
16%8%35%5%35%446%35%
1647
16th to endNight
18%8%25%6%1434439%
1563
May1st to 15thNight
19%5%36%5%3445%5%34%
1485
16th to endNight
10%5%25%5%35%45%7%45%
1406
June1st to 15thNight
9%5%25%42445%8%46%
1320
16th to endNight
9%5%15%5%35%6%5%9%41%
1320
July1st to 15thNight
6%3134245%5%8%53%
1320
16th to endNight
6%323426%5%6%10%48%
1401
August1st to 15thNight
5%42332445%10%52%
1461
16th to endNight
10%323325%45%6%51%
1750
September1st to 15thNight
13%414323346%53%
1683
16th to endNight
8%424425%45%8%49%
1815
October1st to 15thNight
11%6%14423345%50%
1851
16th to endNight
20%7%25%32345%6%37%
2266
November1st to 15thNight
14%6%36%423446%42%
2276
16th to endNight
19%8%35%6%24447%31%
2340
December1st to 15thNight
20%11%5%7%5%24445%28%
2493
16th to endNight
23%14%5%7%6%35%44420%
2688

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
17%14%5%8%7%45%35%6%21%
1432
16th to endDay
13%15%6%10%6%35%445%21%
1536
February1st to 15thDay
14%14%5%8%6%34446%25%
1708
16th to endDay
15%11%5%9%5%35%45%6%27%
1580
March1st to 15thDay
19%11%47%5%3445%6%27%
1771
16th to endDay
16%8%37%7%3445%7%31%
2019
April1st to 15thDay
19%9%45%423347%33%
1971
16th to endDay
19%7%3442445%7%35%
2065
May1st to 15thDay
19%8%36%43445%7%30%
2136
16th to endDay
11%6%35%5%35%45%8%39%
2354
June1st to 15thDay
10%5%25%5%35%5%6%8%41%
2310
16th to endDay
9%425%6%35%5%7%10%38%
2310
July1st to 15thDay
8%4245%45%46%10%43%
2310
16th to endDay
6%3245%46%6%8%9%41%
2459
August1st to 15thDay
7%5%15%5%246%6%9%44%
2165
16th to endDay
10%5%26%5%35%46%8%43%
2100
September1st to 15thDay
13%424335%5%6%7%43%
1936
16th to endDay
8%426%5%245%6%9%42%
1815
October1st to 15thDay
13%6%35%425%5%5%7%41%
1777
16th to endDay
18%7%36%6%345%5%6%32%
1605
November1st to 15thDay
16%6%25%5%2445%6%41%
1582
16th to endDay
18%9%5%6%434446%31%
1620
December1st to 15thDay
19%13%5%9%6%34445%23%
1464
16th to endDay
22%15%6%8%5%33445%20%
1536
January1st to 15thNight
19%12%46%5%34445%28%
2506
16th to endNight
14%12%6%7%8%245%46%26%
2685
February1st to 15thNight
15%11%5%7%5%34345%33%
2143
16th to endNight
17%12%47%5%34345%31%
1893
March1st to 15thNight
18%9%5%7%5%34445%32%
2136
16th to endNight
16%7%46%5%35%46%8%33%
1861
April1st to 15thNight
17%7%35%435%45%6%35%
1647
16th to endNight
19%7%25%6%2434439%
1563
May1st to 15thNight
19%6%26%5%345%5%6%34%
1484
16th to endNight
10%5%16%5%35%45%7%45%
1406
June1st to 15thNight
9%5%25%4245%5%9%46%
1320
16th to endNight
9%5%145%35%6%5%9%41%
1320
July1st to 15thNight
6%3134245%48%53%
1320
16th to endNight
5%313436%5%6%10%48%
1401
August1st to 15thNight
5%42332445%10%51%
1461
16th to endNight
10%323415%45%6%51%
1750
September1st to 15thNight
12%41332235%6%52%
1683
16th to endNight
8%424425%45%8%49%
1815
October1st to 15thNight
11%6%24324345%50%
1851
16th to endNight
20%7%26%32345%6%37%
2266
November1st to 15thNight
14%6%36%42345%6%42%
2276
16th to endNight
19%8%35%5%3445%6%31%
2340
December1st to 15thNight
20%11%5%7%5%34445%28%
2493
16th to endNight
23%14%5%7%7%35%43420%
2688

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%12%6%
1433
16th to endDay
62%5%12%14%4
1536
February1st to 15thDay
59%412%16%6%1
1710
16th to endDay
55%6%12%19%41
1580
March1st to 15thDay
56%6%11%17%7%
1771
16th to endDay
51%5%13%23%5%1
2020
April1st to 15thDay
51%48%21%13%
1971
16th to endDay
46%5%13%18%10%4
2065
May1st to 15thDay
52%6%11%21%7%
2136
16th to endDay
42%6%11%21%15%2
2358
June1st to 15thDay
40%6%11%23%16%1
2310
16th to endDay
38%9%13%18%17%2
2310
July1st to 15thDay
37%6%13%22%17%2
2161
16th to endDay
35%8%17%22%12%2
2292
August1st to 15thDay
33%8%14%25%15%2
2150
16th to endDay
37%6%13%22%16%4
2100
September1st to 15thDay
37%7%10%23%16%4
1936
16th to endDay
36%6%11%25%18%1
1815
October1st to 15thDay
41%5%10%24%15%1
1777
16th to endDay
51%413%20%8%1
1605
November1st to 15thDay
42%5%12%22%14%2
1582
16th to endDay
54%312%21%6%
1620
December1st to 15thDay
63%312%16%4
1464
16th to endDay
65%6%11%11%4
1536
January1st to 15thNight
57%5%12%16%7%
2506
16th to endNight
58%414%15%6%
2685
February1st to 15thNight
53%414%18%8%
2152
16th to endNight
54%6%10%20%7%
1893
March1st to 15thNight
53%5%11%18%8%2
2136
16th to endNight
47%6%15%20%8%1
1861
April1st to 15thNight
49%39%20%15%1
1647
16th to endNight
47%48%20%14%3
1563
May1st to 15thNight
49%6%10%22%10%
1485
16th to endNight
37%6%14%22%16%2
1408
June1st to 15thNight
35%5%13%26%16%1
1320
16th to endNight
37%8%14%20%16%2
1320
July1st to 15thNight
29%6%14%26%20%3
1240
16th to endNight
27%7%16%28%16%3
1305
August1st to 15thNight
26%6%15%26%22%1
1452
16th to endNight
31%6%12%25%19%5%
1750
September1st to 15thNight
31%5%9%26%20%5%
1683
16th to endNight
32%48%27%22%3
1815
October1st to 15thNight
35%410%28%21%
1851
16th to endNight
47%412%24%10%1
2266
November1st to 15thNight
42%49%24%15%3
2276
16th to endNight
51%414%21%6%
2340
December1st to 15thNight
58%412%17%5%
2493
16th to endNight
68%410%11%4
2688

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
25%10%35%16%12%
90
16th to endDay
22%14%35%21%41
96
February1st to 15thDay
20%15%48%15%
90
16th to endDay
23%8%35%17%14%
81
March1st to 15thDay
37%14%27%17%3
81
16th to endDay
24%7%33%22%11%
210
April1st to 15thDay
25%9%30%22%9%2
210
16th to endDay
23%10%22%22%15%4
210
May1st to 15thDay
25%8%25%23%11%5%
228
16th to endDay
14%7%28%25%19%4
398
June1st to 15thDay
13%428%32%16%4
420
16th to endDay
13%7%27%30%15%5%
420
July1st to 15thDay
11%424%28%19%12%
400
16th to endDay
8%321%32%22%12%
445
August1st to 15thDay
9%214%27%27%18%
284
16th to endDay
17%113%24%27%15%
268
September1st to 15thDay
15%212%30%29%9%
255
16th to endDay
11%5%14%30%30%8%
254
October1st to 15thDay
11%427%29%20%5%
217
16th to endDay
26%8%38%25%2
96
November1st to 15thDay
8%10%25%30%16%8%
90
16th to endDay
28%15%38%12%4
90
December1st to 15thDay
20%20%36%18%4
90
16th to endDay
29%21%43%32
96
January1st to 15thNight
24%13%36%20%4
900
16th to endNight
20%13%34%26%3
960
February1st to 15thNight
21%11%36%26%3
744
16th to endNight
22%11%34%24%6%
631
March1st to 15thNight
24%9%34%23%7%
712
16th to endNight
19%8%35%26%9%
616
April1st to 15thNight
20%8%37%26%6%
494
16th to endNight
23%7%31%26%10%1
495
May1st to 15thNight
22%329%32%10%1
495
16th to endNight
12%224%38%21%
515
June1st to 15thNight
13%223%45%15%
495
16th to endNight
10%221%41%22%1
495
July1st to 15thNight
8%218%41%26%2
465
16th to endNight
6%114%42%31%3
522
August1st to 15thNight
6%18%48%31%4
494
16th to endNight
12%12%35%34%5%
525
September1st to 15thNight
15%311%35%29%4
528
16th to endNight
11%419%31%29%3
657
October1st to 15thNight
15%5%23%35%18%1
660
16th to endNight
24%10%30%25%7%
704
November1st to 15thNight
18%10%34%23%12%
700
16th to endNight
24%15%29%24%6%
720
December1st to 15thNight
26%14%31%22%4
873
16th to endNight
31%10%32%21%3
960
Page generated at 2017-03-14 03:34:41. Version ac04

Copyright 2017 A. Danko


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