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 2017-12-02.

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
36%
16267
19%
47881
11%
16220
43%
16220
30%
29290

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%
576
13%
2112
8%
576
31%
576
17%
1425
April1st to 15thNight
27%
539
18%
1845
12%
539
39%
539
26%
1098
April16th to endNight
25%
540
15%
1683
10%
540
33%
540
21%
1126
May1st to 15thNight
31%
539
16%
1620
11%
539
39%
539
23%
1074
May16th to endNight
37%
563
14%
1574
9%
561
42%
561
32%
985
June1st to 15thNight
49%
540
16%
1440
8%
540
52%
540
40%
853
June16th to endNight
49%
540
18%
1440
8%
540
53%
540
49%
796
July1st to 15thNight
60%
510
16%
1447
10%
510
62%
510
42%
816
July16th to endNight
62%
564
19%
1594
18%
531
68%
531
44%
848
August1st to 15thNight
67%
539
22%
1610
24%
536
71%
536
44%
860
August16th to endNight
61%
573
23%
1797
25%
573
65%
573
37%
985
September1st to 15thNight
55%
540
25%
1842
24%
540
62%
540
33%
1029
September16th to endNight
53%
537
27%
1980
22%
537
62%
537
35%
1014
October1st to 15thNight
39%
717
25%
2157
17%
717
45%
717
32%
1273
October16th to endNight
34%
768
26%
2304
13%
768
44%
768
35%
1301
November1st to 15thNight
34%
861
26%
2413
12%
861
45%
861
36%
1397
November16th to endNight
28%
975
21%
2730
8%
975
38%
975
32%
1671
December1st to 15thNight
25%
910
15%
2547
6%
910
32%
910
23%
1731
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%219%423346%37%
48564
Night
9%5%218%323346%42%
48073
Cloud CoverDay
12%6%35%5%2445%7%42%
48562
Night
11%5%2442345%7%48%
48073
TransparencyDay
40%6%13%24%13%1
48260
Night
35%5%13%26%16%2
47881
SeeingDay
13%7%27%30%16%3
6196
Night
13%8%32%32%12%
16268

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
13%9%222%42333429%
2112
April1st to 15thDay
15%8%221%41133433%
2103
16th to endDay
18%7%221%423445%24%
2274
May1st to 15thDay
11%5%322%5%23345%32%
2331
16th to endDay
12%5%221%423347%32%
2538
June1st to 15thDay
8%5%221%423345%37%
2520
16th to endDay
32119%43445%8%40%
2520
July1st to 15thDay
6%3120%42446%7%38%
2422
16th to endDay
4220%32345%9%42%
2466
August1st to 15thDay
6%4113%4345%6%8%41%
2340
16th to endDay
8%4213%424335%46%
2405
September1st to 15thDay
10%3112%423346%46%
2115
16th to endDay
7%3112%324346%48%
1971
October1st to 15thDay
14%6%212%32223445%
1800
16th to endDay
9%7%111%41244447%
1920
November1st to 15thDay
7%5%117%322235%47%
1773
16th to endDay
11%6%219%312335%38%
1560
December1st to 15thDay
11%8%323%5%22345%29%
1450
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
15%6%120%323446%30%
2112
April1st to 15thNight
10%4120%323345%39%
1845
16th to endNight
14%7%222%32243431%
1683
May1st to 15thNight
10%5%122%424236%35%
1619
16th to endNight
8%5%121%422247%39%
1572
June1st to 15thNight
6%2119%3125%5%7%43%
1440
16th to endNight
2118%11336%8%49%
1440
July1st to 15thNight
5%2119%22335%8%45%
1534
16th to endNight
22119%32436%7%45%
1702
August1st to 15thNight
31113%32335%9%52%
1620
16th to endNight
7%3111%313346%52%
1797
September1st to 15thNight
9%3112%42325%6%48%
1842
16th to endNight
8%212%322436%53%
1980
October1st to 15thNight
12%6%111%22223449%
2157
16th to endNight
11%4111%22223452%
2304
November1st to 15thNight
7%3116%323245%49%
2413
16th to endNight
10%5%218%212345%43%
2730
December1st to 15thNight
12%6%221%324235%33%
2547
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
18%11%36%424446%33%
2110
April1st to 15thDay
17%8%35%5%22445%40%
2103
16th to endDay
23%8%25%424446%32%
2274
May1st to 15thDay
15%6%46%6%3445%6%36%
2331
16th to endDay
14%6%35%5%34448%39%
2538
June1st to 15thDay
10%6%25%5%335%5%7%44%
2520
16th to endDay
6%3135%35%5%6%9%47%
2520
July1st to 15thDay
8%324426%5%6%9%45%
2422
16th to endDay
5%3144235%7%10%51%
2466
August1st to 15thDay
7%4245%35%5%7%10%43%
2340
16th to endDay
10%5%25%5%34435%48%
2405
September1st to 15thDay
11%31342345%7%50%
2115
16th to endDay
8%31442445%8%52%
1971
October1st to 15thDay
15%6%24322335%49%
1800
16th to endDay
12%7%2342244450%
1920
November1st to 15thDay
9%6%14323246%54%
1773
16th to endDay
13%8%34423446%43%
1560
December1st to 15thDay
12%9%47%6%3445%7%35%
1450
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
19%8%24425%45%7%34%
2112
April1st to 15thNight
13%5%2432435%6%47%
1845
16th to endNight
16%8%26%323445%41%
1683
May1st to 15thNight
13%6%36%434348%41%
1619
16th to endNight
9%5%25%433349%48%
1572
June1st to 15thNight
7%2233246%6%9%51%
1440
16th to endNight
42122245%7%10%56%
1440
July1st to 15thNight
7%21232446%10%53%
1534
16th to endNight
421343446%9%55%
1702
August1st to 15thNight
421432346%10%55%
1620
16th to endNight
9%324313447%55%
1797
September1st to 15thNight
11%31342435%7%51%
1842
16th to endNight
10%214323447%56%
1980
October1st to 15thNight
14%6%23222345%52%
2157
16th to endNight
13%5%13222235%55%
2304
November1st to 15thNight
8%42442335%6%55%
2413
16th to endNight
12%6%3331335%6%49%
2730
December1st to 15thNight
14%8%35%335%346%41%
2547
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
53%6%13%19%7%1
2112
April1st to 15thDay
46%411%24%12%
2103
16th to endDay
51%5%11%20%9%
2274
May1st to 15thDay
48%6%12%20%11%
2331
16th to endDay
42%7%14%23%10%
2542
June1st to 15thDay
38%6%13%24%14%1
2520
16th to endDay
30%9%15%28%14%2
2520
July1st to 15thDay
34%6%16%28%10%3
2281
16th to endDay
25%8%17%30%16%2
2311
August1st to 15thDay
32%9%16%26%15%
2326
16th to endDay
36%5%10%24%16%5%
2405
September1st to 15thDay
32%6%12%26%18%3
2115
16th to endDay
30%6%11%30%19%1
1971
October1st to 15thDay
38%310%25%19%2
1800
16th to endDay
35%410%27%18%4
1920
November1st to 15thDay
32%313%28%19%3
1773
16th to endDay
40%413%28%13%
1560
December1st to 15thDay
48%6%16%19%8%
1450
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
48%6%12%22%8%1
2112
April1st to 15thNight
35%6%10%27%17%1
1845
16th to endNight
44%6%9%23%13%1
1683
May1st to 15thNight
41%7%10%24%14%1
1620
16th to endNight
34%7%16%25%13%2
1574
June1st to 15thNight
26%8%17%28%15%3
1440
16th to endNight
19%7%18%29%20%4
1440
July1st to 15thNight
24%7%17%31%14%4
1447
16th to endNight
23%6%14%34%20%1
1594
August1st to 15thNight
23%6%18%33%16%2
1610
16th to endNight
28%5%12%24%20%8%
1797
September1st to 15thNight
31%5%9%26%21%5%
1842
16th to endNight
27%5%11%34%19%2
1980
October1st to 15thNight
34%49%24%22%4
2157
16th to endNight
31%311%25%24%3
2304
November1st to 15thNight
29%414%24%22%4
2413
16th to endNight
34%411%29%18%1
2730
December1st to 15thNight
44%5%14%25%9%
2547
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
35%10%30%22%1
96
April1st to 15thDay
22%9%33%25%9%
222
16th to endDay
30%11%32%18%7%
384
May1st to 15thDay
16%13%30%27%10%1
468
16th to endDay
17%8%34%24%13%1
517
June1st to 15thDay
11%424%34%20%4
495
16th to endDay
6%5%34%30%20%3
495
July1st to 15thDay
10%218%40%20%7%
475
16th to endDay
4112%45%31%4
515
August1st to 15thDay
8%15%40%29%5%
493
16th to endDay
9%418%34%24%9%
445
September1st to 15thDay
10%319%34%24%7%
270
16th to endDay
9%228%41%14%3
135
October1st to 15thDay
20%8%30%30%5%4
135
16th to endDay
9%13%38%31%6%
144
November1st to 15thDay
10%9%37%28%9%5%
135
16th to endDay
28%11%41%13%5%
135
December1st to 15thDay
14%24%36%15%44
94
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
24%10%35%22%6%
576
April1st to 15thNight
15%10%37%30%5%
539
16th to endNight
20%10%33%26%7%
540
May1st to 15thNight
15%9%33%33%7%
540
16th to endNight
12%5%34%33%12%
563
June1st to 15thNight
8%324%45%17%
540
16th to endNight
5%230%43%18%
540
July1st to 15thNight
7%18%43%27%1
510
16th to endNight
4113%47%32%1
564
August1st to 15thNight
415%51%26%1
539
16th to endNight
10%115%39%28%4
573
September1st to 15thNight
12%219%35%27%2
540
16th to endNight
10%324%40%19%1
537
October1st to 15thNight
17%6%29%32%12%1
717
16th to endNight
15%8%37%29%8%
768
November1st to 15thNight
10%11%34%34%9%
861
16th to endNight
16%11%37%26%8%
975
December1st to 15thNight
19%11%35%26%6%
910
16th to endNight
19%10%36%28%5%
960
Page generated at 2017-12-03 10:16:38. Version ac04

Copyright 2017 A. Danko


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