Burnt Chimney
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Burnt Chimney clear sky chart from 2005-11-05 to 2019-06-10.

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
44%
18166
21%
54120
13%
18127
53%
18127
27%
34228

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
26%
838
23%
2717
9%
836
44%
836
21%
1666
January16th to endNight
26%
896
24%
2912
10%
896
43%
896
23%
1768
February1st to 15thNight
24%
822
21%
2677
9%
821
40%
821
23%
1636
February16th to endNight
24%
735
25%
2183
10%
735
40%
735
24%
1389
March1st to 15thNight
29%
840
24%
2310
11%
840
41%
840
26%
1486
March16th to endNight
33%
896
20%
2464
11%
896
41%
896
27%
1612
April1st to 15thNight
32%
838
21%
2177
7%
838
41%
838
28%
1422
April16th to endNight
40%
766
20%
2012
8%
766
47%
766
30%
1323
May1st to 15thNight
44%
630
17%
1890
8%
630
51%
630
24%
1256
May16th to endNight
58%
657
15%
1972
12%
657
60%
657
29%
1271
June1st to 15thNight
67%
612
17%
1836
16%
612
69%
612
31%
1143
June16th to endNight
72%
585
17%
1755
15%
585
74%
585
34%
1064
July1st to 15thNight
71%
555
14%
1665
13%
555
72%
555
29%
1078
July16th to endNight
73%
612
16%
1739
14%
579
75%
579
31%
1100
August1st to 15thNight
66%
575
19%
1715
16%
572
68%
572
28%
1108
August16th to endNight
71%
744
18%
1986
14%
744
72%
744
31%
1302
September1st to 15thNight
62%
780
23%
2024
17%
780
64%
780
31%
1351
September16th to endNight
50%
777
19%
2145
16%
777
52%
777
23%
1502
October1st to 15thNight
51%
780
24%
2338
22%
780
58%
780
28%
1468
October16th to endNight
43%
832
31%
2496
20%
832
59%
832
34%
1417
November1st to 15thNight
43%
820
26%
2483
18%
820
54%
820
29%
1507
November16th to endNight
40%
840
26%
2779
17%
840
53%
840
28%
1571
December1st to 15thNight
28%
840
21%
2933
10%
840
42%
840
19%
1847
December16th to endNight
25%
896
21%
2912
8%
896
40%
896
19%
1941

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%5%245%35%5%5%7%41%
54364
Night
14%42442445%7%44%
54313
Cloud CoverDay
14%4245%3445%7%41%
54374
Night
14%42442445%7%45%
54317
TransparencyDay
40%7%12%21%15%3
54075
Night
37%6%11%22%17%3
54120
SeeingDay
19%8%21%22%18%9%
7873
Night
16%7%25%29%18%2
18172

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
15%5%2442445%7%43%
1881
16th to endDay
13%7%245%24445%45%
2016
February1st to 15thDay
13%6%25%5%35%447%41%
1845
16th to endDay
16%6%25%5%3445%6%39%
1857
March1st to 15thDay
14%6%2442435%6%45%
2299
16th to endDay
17%6%25%424445%41%
2464
April1st to 15thDay
12%5%24424448%47%
2431
16th to endDay
16%4245%3445%6%42%
2564
May1st to 15thDay
16%5%245%35%5%6%8%34%
2721
16th to endDay
13%315%5%35%5%7%9%38%
2847
June1st to 15thDay
10%3145%36%5%7%9%40%
2652
16th to endDay
8%425%6%36%6%7%9%39%
2535
July1st to 15thDay
10%5%26%6%37%6%7%9%33%
2535
16th to endDay
8%426%6%46%7%8%11%30%
2673
August1st to 15thDay
13%4246%47%6%7%10%31%
2487
16th to endDay
10%5%26%7%445%6%9%35%
2555
September1st to 15thDay
13%5%15%5%2445%6%43%
2264
16th to endDay
23%5%24434447%35%
2145
October1st to 15thDay
18%413313335%49%
1950
16th to endDay
12%413423335%53%
2080
November1st to 15thDay
15%423333345%50%
2032
16th to endDay
13%41441445%6%49%
1835
December1st to 15thDay
14%425%3445%6%6%42%
1680
16th to endDay
20%5%25%434346%39%
2016
January1st to 15thNight
15%5%24424445%47%
2717
16th to endNight
14%5%2442435%5%46%
2912
February1st to 15thNight
15%6%2432345%6%44%
2675
16th to endNight
14%6%2432445%7%43%
2183
March1st to 15thNight
14%4243245%5%6%44%
2298
16th to endNight
16%414424447%44%
2464
April1st to 15thNight
14%5%2442345%7%45%
2177
16th to endNight
15%315%42445%7%45%
2012
May1st to 15thNight
15%5%25%425%45%8%40%
1890
16th to endNight
13%314435%5%5%10%41%
1970
June1st to 15thNight
10%213425%5%7%11%43%
1836
16th to endNight
7%2145%3347%11%47%
1755
July1st to 15thNight
7%324436%5%8%8%44%
1755
16th to endNight
6%325%5%46%6%7%12%40%
1847
August1st to 15thNight
12%415%5%2346%10%42%
1726
16th to endNight
8%325%5%36%6%6%10%41%
1986
September1st to 15thNight
13%5%25%4245%5%7%45%
2024
16th to endNight
21%5%245%24446%37%
2145
October1st to 15thNight
17%414424345%46%
2338
16th to endNight
12%31432334456%
2496
November1st to 15thNight
16%42431333450%
2483
16th to endNight
13%42332345%6%51%
2779
December1st to 15thNight
16%5%35%5%2345%5%42%
2933
16th to endNight
17%6%35%5%34447%38%
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
15%5%2443435%7%43%
1881
16th to endDay
13%7%245%34445%46%
2016
February1st to 15thDay
13%6%25%435%447%41%
1845
16th to endDay
17%5%25%5%3445%6%40%
1857
March1st to 15thDay
14%5%2432436%6%45%
2310
16th to endDay
18%5%2432345%6%41%
2463
April1st to 15thDay
13%5%2341345%7%48%
2431
16th to endDay
17%4245%24447%42%
2564
May1st to 15thDay
17%5%345%35%46%8%34%
2721
16th to endDay
13%315%6%35%5%6%9%38%
2847
June1st to 15thDay
11%314446%6%7%8%40%
2652
16th to endDay
9%325%5%36%6%6%9%40%
2535
July1st to 15thDay
11%5%26%6%37%6%7%9%33%
2535
16th to endDay
9%436%7%47%7%9%10%31%
2673
August1st to 15thDay
14%425%5%46%6%7%10%32%
2487
16th to endDay
11%5%26%6%45%5%6%9%36%
2555
September1st to 15thDay
14%5%25%5%34446%44%
2264
16th to endDay
24%425%423446%35%
2145
October1st to 15thDay
20%412313345%50%
1950
16th to endDay
12%423423335%53%
2080
November1st to 15thDay
15%323323435%50%
2032
16th to endDay
14%31431335%7%49%
1835
December1st to 15thDay
14%5%15%43445%7%43%
1680
16th to endDay
21%424433337%39%
2016
January1st to 15thNight
16%424324345%47%
2717
16th to endNight
15%5%24324345%46%
2912
February1st to 15thNight
15%5%2432345%5%45%
2668
16th to endNight
14%5%24424447%43%
2183
March1st to 15thNight
15%42442446%6%44%
2310
16th to endNight
16%414424347%45%
2464
April1st to 15thNight
14%5%24414347%45%
2177
16th to endNight
16%414423448%45%
2012
May1st to 15thNight
16%5%245%35%45%8%40%
1889
16th to endNight
13%315%435%45%10%42%
1970
June1st to 15thNight
10%313435%6%7%12%43%
1836
16th to endNight
7%3144335%6%12%48%
1755
July1st to 15thNight
8%324435%5%8%8%44%
1755
16th to endNight
7%3146%45%6%7%12%40%
1847
August1st to 15thNight
13%325%5%3346%10%42%
1726
16th to endNight
8%325%5%35%5%7%10%42%
1986
September1st to 15thNight
13%6%25%4145%5%7%45%
2024
16th to endNight
22%425%423446%38%
2145
October1st to 15thNight
18%314423436%47%
2338
16th to endNight
12%31332323456%
2496
November1st to 15thNight
16%5%2431233451%
2483
16th to endNight
14%41331335%6%51%
2779
December1st to 15thNight
16%5%345%2435%5%43%
2933
16th to endNight
17%6%25%5%24447%38%
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
39%5%12%20%17%4
1882
16th to endDay
38%5%8%25%17%4
2016
February1st to 15thDay
40%6%11%21%17%2
1847
16th to endDay
42%5%12%21%15%2
1857
March1st to 15thDay
38%5%11%22%18%5%
2310
16th to endDay
43%6%8%21%16%4
2464
April1st to 15thDay
34%5%12%25%15%6%
2431
16th to endDay
41%6%10%19%15%6%
2564
May1st to 15thDay
44%8%14%18%10%2
2721
16th to endDay
39%9%16%24%9%1
2851
June1st to 15thDay
37%9%16%22%11%1
2652
16th to endDay
37%10%14%18%15%2
2535
July1st to 15thDay
42%9%15%16%13%2
2396
16th to endDay
40%11%17%18%11%
2518
August1st to 15thDay
43%9%15%20%9%
2474
16th to endDay
42%9%16%18%11%1
2555
September1st to 15thDay
39%7%13%19%18%2
2264
16th to endDay
48%5%9%18%16%
2145
October1st to 15thDay
36%410%26%17%4
1950
16th to endDay
33%29%27%21%5%
2080
November1st to 15thDay
36%410%17%24%7%
2032
16th to endDay
34%5%9%24%23%3
1835
December1st to 15thDay
40%6%11%20%16%4
1680
16th to endDay
45%410%21%14%2
2016
January1st to 15thNight
39%49%18%19%7%
2717
16th to endNight
37%5%9%23%19%4
2912
February1st to 15thNight
39%410%24%17%3
2677
16th to endNight
39%5%11%24%15%3
2183
March1st to 15thNight
38%6%8%25%17%4
2310
16th to endNight
40%411%21%18%3
2464
April1st to 15thNight
37%5%11%23%16%5%
2177
16th to endNight
38%5%11%19%18%5%
2012
May1st to 15thNight
41%7%13%21%13%1
1890
16th to endNight
36%8%16%26%9%1
1972
June1st to 15thNight
32%10%18%24%13%1
1836
16th to endNight
29%10%16%22%18%3
1755
July1st to 15thNight
32%12%14%21%13%4
1665
16th to endNight
33%10%18%24%12%1
1739
August1st to 15thNight
36%9%16%21%15%1
1715
16th to endNight
35%9%16%24%12%2
1986
September1st to 15thNight
38%7%12%20%17%4
2024
16th to endNight
47%5%8%18%17%1
2145
October1st to 15thNight
39%5%8%24%18%3
2338
16th to endNight
31%36%27%25%5%
2496
November1st to 15thNight
37%47%19%22%8%
2483
16th to endNight
33%49%24%23%4
2779
December1st to 15thNight
43%5%8%23%15%3
2933
16th to endNight
45%6%10%20%14%2
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
21%22%36%16%21
180
16th to endDay
24%26%31%14%3
192
February1st to 15thDay
26%22%35%11%3
180
16th to endDay
26%16%34%17%4
224
March1st to 15thDay
22%19%31%21%5%
390
16th to endDay
21%14%28%26%7%
416
April1st to 15thDay
19%14%29%23%10%2
390
16th to endDay
21%6%27%22%16%5%
379
May1st to 15thDay
18%10%28%21%13%8%
408
16th to endDay
17%119%26%23%10%
459
June1st to 15thDay
12%318%27%24%13%
411
16th to endDay
11%218%25%29%13%
375
July1st to 15thDay
13%11%26%31%15%
365
16th to endDay
11%7%28%32%19%
390
August1st to 15thDay
15%111%20%31%20%
358
16th to endDay
12%27%19%30%28%
396
September1st to 15thDay
20%212%15%25%24%
375
16th to endDay
29%29%22%23%12%
374
October1st to 15thDay
22%316%23%24%9%
375
16th to endDay
14%8%27%27%18%4
400
November1st to 15thDay
24%9%23%22%18%1
360
16th to endDay
9%19%23%30%14%2
164
December1st to 15thDay
26%10%34%20%6%
120
16th to endDay
29%13%38%16%2
192
January1st to 15thNight
19%16%33%25%4
840
16th to endNight
18%12%38%27%2
896
February1st to 15thNight
20%13%38%25%2
824
16th to endNight
19%13%41%23%2
735
March1st to 15thNight
16%13%36%29%4
840
16th to endNight
19%8%33%29%8%
896
April1st to 15thNight
16%13%32%27%8%
838
16th to endNight
17%6%29%30%14%
766
May1st to 15thNight
17%426%33%16%
630
16th to endNight
13%216%29%33%4
659
June1st to 15thNight
9%113%34%36%4
612
16th to endNight
8%110%36%38%5%
585
July1st to 15thNight
9%19%33%40%6%
555
16th to endNight
7%18%34%41%7%
612
August1st to 15thNight
14%6%35%38%4
575
16th to endNight
10%7%30%42%9%
744
September1st to 15thNight
14%111%28%36%8%
780
16th to endNight
24%212%23%31%4
777
October1st to 15thNight
19%416%29%23%5%
780
16th to endNight
14%8%28%31%15%1
832
November1st to 15thNight
18%7%26%31%13%2
820
16th to endNight
17%12%26%29%13%
840
December1st to 15thNight
21%10%33%27%7%
840
16th to endNight
20%11%35%28%3
896
Page generated at 2019-06-10 19:29:47. Version ac04

Copyright 2019 A. Danko


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