Bearcat Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bearcat Observatory clear sky chart from 2005-11-05 to 2017-03-25.

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
35%
15429
19%
45352
11%
15382
42%
15382
30%
27863

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
28%
900
21%
2336
9%
895
37%
895
30%
1492
January16th to endNight
23%
960
18%
2496
7%
960
31%
960
29%
1628
February1st to 15thNight
23%
880
14%
2288
5%
876
28%
876
22%
1628
February16th to endNight
22%
696
18%
1958
5%
696
32%
696
30%
1225
March1st to 15thNight
30%
540
20%
1980
12%
540
41%
540
25%
1155
March16th to endNight
23%
558
14%
2046
8%
558
32%
558
17%
1361
April1st to 15thNight
27%
494
20%
1691
12%
494
40%
494
27%
996
April16th to endNight
25%
495
14%
1543
9%
495
33%
495
22%
1024
May1st to 15thNight
29%
494
16%
1485
10%
494
38%
494
22%
1000
May16th to endNight
37%
515
12%
1439
8%
513
41%
513
32%
907
June1st to 15thNight
47%
495
16%
1320
8%
495
50%
495
37%
798
June16th to endNight
49%
495
16%
1320
7%
495
53%
495
50%
725
July1st to 15thNight
59%
465
16%
1319
11%
465
61%
465
42%
746
July16th to endNight
61%
522
18%
1468
16%
489
67%
489
44%
780
August1st to 15thNight
66%
494
23%
1475
25%
491
70%
491
44%
795
August16th to endNight
58%
525
21%
1646
22%
525
62%
525
35%
922
September1st to 15thNight
53%
495
25%
1688
24%
495
59%
495
30%
969
September16th to endNight
52%
492
25%
1815
21%
492
61%
492
35%
931
October1st to 15thNight
41%
657
26%
1977
18%
657
46%
657
34%
1144
October16th to endNight
34%
704
23%
2112
12%
704
43%
704
34%
1210
November1st to 15thNight
35%
793
27%
2222
12%
793
47%
793
38%
1258
November16th to endNight
27%
900
19%
2520
8%
900
36%
900
30%
1569
December1st to 15thNight
24%
900
15%
2520
6%
900
31%
900
23%
1720
December16th to endNight
21%
960
17%
2688
6%
960
31%
960
22%
1880

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
10%6%220%423346%36%
45600
Night
9%5%219%323345%41%
45544
Cloud CoverDay
12%7%35%5%2445%7%42%
45598
Night
11%5%2442445%7%47%
45544
TransparencyDay
41%6%13%24%13%1
45296
Night
35%5%13%26%16%2
45352
SeeingDay
14%7%27%30%17%3
5166
Night
13%8%32%32%11%
15430

By Month

Percentage Cloud Cover SW (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
8%6%223%6%3333434%
1601
16th to endDay
11%10%323%323335%29%
1728
February1st to 15thDay
10%7%222%5%34347%28%
1575
16th to endDay
10%7%320%423345%33%
1524
March1st to 15thDay
9%10%322%422336%31%
1980
16th to endDay
12%8%223%423335%30%
2045
April1st to 15thDay
14%8%222%31133434%
1927
16th to endDay
18%7%223%323435%24%
2084
May1st to 15thDay
12%5%223%5%23345%29%
2136
16th to endDay
12%5%223%423337%30%
2321
June1st to 15thDay
9%6%223%423345%34%
2310
16th to endDay
32121%43446%8%39%
2310
July1st to 15thDay
7%3221%42446%7%35%
2220
16th to endDay
4221%33345%8%41%
2284
August1st to 15thDay
6%4214%4245%6%8%40%
2145
16th to endDay
8%5%214%424335%44%
2204
September1st to 15thDay
10%3113%423346%44%
1939
16th to endDay
7%3113%324346%48%
1807
October1st to 15thDay
12%6%212%312235%47%
1650
16th to endDay
10%7%112%41244446%
1760
November1st to 15thDay
6%5%118%322235%49%
1634
16th to endDay
12%6%320%312335%36%
1440
December1st to 15thDay
11%8%323%5%22345%28%
1440
16th to endDay
11%9%325%5%2333329%
1536
January1st to 15thNight
6%4221%5%33435%39%
2336
16th to endNight
7%8%321%32324437%
2496
February1st to 15thNight
10%8%222%433345%32%
2278
16th to endNight
7%7%320%313335%39%
1958
March1st to 15thNight
10%5%220%322245%40%
1980
16th to endNight
14%6%121%323446%30%
2046
April1st to 15thNight
10%4122%323245%39%
1691
16th to endNight
12%7%224%32243431%
1543
May1st to 15thNight
11%5%123%423236%33%
1484
16th to endNight
7%5%123%333247%37%
1437
June1st to 15thNight
7%2121%3125%47%40%
1320
16th to endNight
2120%11336%8%49%
1320
July1st to 15thNight
5%2120%12335%9%43%
1406
16th to endNight
31120%32336%7%44%
1576
August1st to 15thNight
31113%32336%9%51%
1485
16th to endNight
7%3112%313346%51%
1646
September1st to 15thNight
10%3113%42325%6%46%
1688
16th to endNight
7%213%322436%52%
1815
October1st to 15thNight
11%6%111%22223450%
1977
16th to endNight
11%4112%22223451%
2112
November1st to 15thNight
6%3117%322235%50%
2222
16th to endNight
11%5%219%212345%41%
2520
December1st to 15thNight
13%7%222%324235%33%
2520
16th to endNight
12%7%422%42222433%
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
9%7%36%7%44346%41%
1601
16th to endDay
12%10%47%425%346%36%
1728
February1st to 15thDay
13%8%47%5%35%45%7%34%
1575
16th to endDay
12%9%35%43345%7%39%
1524
March1st to 15thDay
12%11%46%5%23446%37%
1980
16th to endDay
17%10%36%5%24446%34%
2043
April1st to 15thDay
16%8%35%5%22445%41%
1927
16th to endDay
23%8%25%424446%33%
2084
May1st to 15thDay
16%6%46%6%3445%6%34%
2136
16th to endDay
15%6%35%5%34448%39%
2321
June1st to 15thDay
10%7%35%5%335%5%7%42%
2310
16th to endDay
6%3235%35%5%6%9%46%
2310
July1st to 15thDay
9%324426%5%7%9%44%
2220
16th to endDay
5%3144245%7%10%50%
2284
August1st to 15thDay
7%4245%25%6%7%9%43%
2145
16th to endDay
10%5%25%5%24445%47%
2204
September1st to 15thDay
12%42442345%6%48%
1939
16th to endDay
8%32432445%8%52%
1807
October1st to 15thDay
14%6%24322336%51%
1650
16th to endDay
12%7%2442244450%
1760
November1st to 15thDay
8%6%13323247%56%
1634
16th to endDay
14%9%44423446%42%
1440
December1st to 15thDay
12%9%47%6%3445%7%35%
1440
16th to endDay
14%11%49%6%2445%6%32%
1536
January1st to 15thNight
8%4345%35%5%5%7%46%
2336
16th to endNight
8%8%45%42445%6%45%
2496
February1st to 15thNight
13%9%47%5%3445%5%37%
2278
16th to endNight
9%8%35%423446%48%
1958
March1st to 15thNight
11%6%24423346%48%
1980
16th to endNight
18%7%24425%45%7%35%
2046
April1st to 15thNight
13%5%1432435%6%48%
1691
16th to endNight
15%8%26%322445%42%
1543
May1st to 15thNight
14%6%36%434348%39%
1484
16th to endNight
9%5%25%443349%47%
1437
June1st to 15thNight
8%2234246%5%10%50%
1320
16th to endNight
42122245%7%10%56%
1320
July1st to 15thNight
7%21222446%10%52%
1406
16th to endNight
421343447%9%54%
1576
August1st to 15thNight
422432346%11%54%
1485
16th to endNight
10%324313447%53%
1646
September1st to 15thNight
12%41442435%6%49%
1688
16th to endNight
9%214323447%56%
1815
October1st to 15thNight
13%6%22222345%54%
1977
16th to endNight
14%5%13222235%54%
2112
November1st to 15thNight
7%423323347%56%
2222
16th to endNight
13%6%3331335%6%48%
2520
December1st to 15thNight
14%8%35%335%346%40%
2520
16th to endNight
15%8%5%6%5%23446%37%
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
44%415%20%13%
1602
16th to endDay
49%416%19%9%
1728
February1st to 15thDay
48%6%14%21%7%
1576
16th to endDay
45%5%13%21%12%1
1524
March1st to 15thDay
47%5%12%23%10%1
1980
16th to endDay
51%6%13%20%7%1
2045
April1st to 15thDay
45%411%24%12%
1927
16th to endDay
51%5%11%20%9%
2084
May1st to 15thDay
50%6%13%19%9%
2136
16th to endDay
43%7%14%24%9%
2325
June1st to 15thDay
40%7%13%24%12%1
2310
16th to endDay
30%9%15%27%13%2
2310
July1st to 15thDay
35%6%16%27%10%3
2079
16th to endDay
26%7%17%30%15%1
2129
August1st to 15thDay
32%9%15%25%16%
2131
16th to endDay
38%5%10%23%15%5%
2204
September1st to 15thDay
34%6%11%24%18%4
1939
16th to endDay
30%6%11%28%21%1
1807
October1st to 15thDay
35%311%26%20%2
1650
16th to endDay
36%411%27%17%3
1760
November1st to 15thDay
29%312%30%20%3
1634
16th to endDay
42%413%26%12%
1440
December1st to 15thDay
48%6%16%19%8%
1440
16th to endDay
52%5%13%18%9%
1536
January1st to 15thNight
35%6%13%29%15%
2336
16th to endNight
38%5%15%26%13%1
2496
February1st to 15thNight
47%5%13%21%11%1
2288
16th to endNight
37%314%22%18%2
1958
March1st to 15thNight
36%5%11%27%16%2
1980
16th to endNight
47%6%12%22%9%1
2046
April1st to 15thNight
35%6%9%27%18%2
1691
16th to endNight
43%6%10%24%13%1
1543
May1st to 15thNight
43%7%11%24%11%1
1485
16th to endNight
34%7%16%25%13%2
1439
June1st to 15thNight
27%9%17%27%14%3
1320
16th to endNight
19%7%18%30%19%3
1320
July1st to 15thNight
25%7%17%32%12%4
1319
16th to endNight
22%6%14%35%19%1
1468
August1st to 15thNight
23%6%18%32%16%2
1475
16th to endNight
30%5%11%23%19%8%
1646
September1st to 15thNight
33%5%9%23%21%6%
1688
16th to endNight
27%410%33%20%2
1815
October1st to 15thNight
33%49%25%23%4
1977
16th to endNight
32%311%25%21%3
2112
November1st to 15thNight
27%413%24%23%5%
2222
16th to endNight
36%411%28%17%1
2520
December1st to 15thNight
45%5%15%24%9%
2520
16th to endNight
48%412%20%11%1
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
23%10%40%22%31
90
16th to endDay
21%12%38%20%6%
96
February1st to 15thDay
10%20%45%18%5%
90
16th to endDay
12%22%38%17%9%
81
March1st to 15thDay
22%13%36%25%11
90
16th to endDay
24%12%37%24%1
78
April1st to 15thDay
19%9%34%25%10%1
166
16th to endDay
29%10%32%19%7%
314
May1st to 15thDay
19%14%30%23%11%1
393
16th to endDay
18%7%32%24%15%1
437
June1st to 15thDay
13%5%27%32%17%3
420
16th to endDay
5%331%32%23%3
420
July1st to 15thDay
11%319%39%20%6%
400
16th to endDay
4113%45%31%3
445
August1st to 15thDay
7%16%39%30%5%
418
16th to endDay
10%417%34%24%8%
372
September1st to 15thDay
12%320%35%22%5%
214
16th to endDay
6%325%40%18%5%
90
October1st to 15thDay
12%7%25%41%6%6%
90
16th to endDay
9%8%39%36%6%
96
November1st to 15thDay
410%26%37%13%7%
90
16th to endDay
37%12%38%7%3
90
December1st to 15thDay
15%25%37%13%34
90
16th to endDay
23%20%37%17%
96
January1st to 15thNight
10%13%40%28%7%
900
16th to endNight
12%12%40%29%5%
960
February1st to 15thNight
16%10%39%28%4
880
16th to endNight
14%12%41%22%6%1
696
March1st to 15thNight
15%11%34%30%8%
540
16th to endNight
22%10%36%23%6%
558
April1st to 15thNight
15%10%37%30%5%
494
16th to endNight
20%10%33%26%8%
495
May1st to 15thNight
16%9%33%32%7%1
495
16th to endNight
12%5%34%33%13%
515
June1st to 15thNight
8%325%45%16%
495
16th to endNight
4229%43%20%
495
July1st to 15thNight
7%18%44%26%1
465
16th to endNight
4113%46%32%1
522
August1st to 15thNight
4114%51%26%2
494
16th to endNight
11%216%37%29%4
525
September1st to 15thNight
14%219%35%26%2
495
16th to endNight
10%425%38%20%1
492
October1st to 15thNight
16%6%28%33%13%1
657
16th to endNight
16%7%36%29%8%
704
November1st to 15thNight
9%11%33%35%9%
793
16th to endNight
17%11%36%25%8%
900
December1st to 15thNight
19%12%35%26%5%
900
16th to endNight
19%10%36%28%5%
960
Page generated at 2017-03-26 12:16:43. Version ac04

Copyright 2017 A. Danko


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