Canebrake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Canebrake 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
60%
15906
36%
47759
26%
15869
71%
15869
57%
21032

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
57%
716
28%
2506
23%
716
67%
716
46%
1110
January16th to endNight
53%
768
34%
2442
26%
768
66%
768
43%
1192
February1st to 15thNight
52%
700
33%
2111
25%
700
63%
700
48%
1016
February16th to endNight
48%
632
33%
1895
26%
632
61%
632
48%
902
March1st to 15thNight
48%
720
28%
2160
19%
720
63%
720
47%
1029
March16th to endNight
46%
768
34%
2007
18%
768
59%
768
50%
1031
April1st to 15thNight
40%
719
34%
1799
11%
719
54%
719
50%
920
April16th to endNight
45%
720
39%
1800
12%
720
59%
720
61%
841
May1st to 15thNight
44%
581
36%
1661
17%
581
55%
581
63%
695
May16th to endNight
47%
562
34%
1685
18%
561
59%
561
57%
690
June1st to 15thNight
55%
378
37%
1458
28%
378
72%
378
69%
472
June16th to endNight
60%
360
42%
1440
36%
360
77%
360
78%
423
July1st to 15thNight
79%
340
35%
1360
35%
340
87%
340
66%
453
July16th to endNight
84%
501
38%
1531
36%
469
85%
469
65%
622
August1st to 15thNight
80%
717
38%
1790
23%
713
82%
713
80%
794
August16th to endNight
85%
764
45%
1910
27%
764
87%
764
82%
851
September1st to 15thNight
85%
720
43%
1824
29%
720
89%
720
76%
832
September16th to endNight
76%
716
49%
1980
38%
716
87%
716
82%
781
October1st to 15thNight
66%
720
39%
2013
29%
720
78%
720
66%
897
October16th to endNight
68%
768
46%
2355
39%
768
81%
768
64%
969
November1st to 15thNight
66%
760
36%
2470
31%
760
78%
760
58%
1020
November16th to endNight
66%
780
37%
2535
35%
780
74%
780
55%
1080
December1st to 15thNight
57%
728
33%
2366
22%
728
71%
728
44%
1107
December16th to endNight
49%
768
31%
2661
25%
768
61%
768
36%
1305

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
2112212346%71%
48687
Night
112212346%71%
47944
TransparencyDay
13%27%17%27%32%
48370
Night
13%28%19%28%26%
47761
SeeingDay
7%16%34%30%9%2
6096
Night
38%24%31%25%7%
15916

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
311231346%8%62%
1432
16th to endDay
6%41331335%7%58%
1777
February1st to 15thDay
231331435%9%59%
1751
16th to endDay
43144245%5%7%57%
1579
March1st to 15thDay
12123346%6%8%60%
1800
16th to endDay
22113146%6%8%58%
2215
April1st to 15thDay
2212323446%65%
2149
16th to endDay
11113348%72%
2160
May1st to 15thDay
11212337%73%
2289
16th to endDay
2212112345%72%
2429
June1st to 15thDay
111112245%77%
2499
16th to endDay
1112386%
2520
July1st to 15thDay
211212335%74%
2520
16th to endDay
2112213246%71%
2525
August1st to 15thDay
11111222283%
2160
16th to endDay
11123482%
2292
September1st to 15thDay
1121223380%
2136
16th to endDay
1112385%
1980
October1st to 15thDay
211212235%75%
1944
16th to endDay
2212112335%74%
1866
November1st to 15thDay
1212112247%71%
1719
16th to endDay
212213447%67%
1755
December1st to 15thDay
23332345%8%62%
1630
16th to endDay
331331446%8%57%
1560
January1st to 15thNight
331332335%8%62%
2506
16th to endNight
5%413323347%60%
2442
February1st to 15thNight
131332345%8%60%
2101
16th to endNight
5%2332346%8%60%
1895
March1st to 15thNight
131332446%8%61%
2160
16th to endNight
2133246%6%7%61%
2007
April1st to 15thNight
1212324347%67%
1799
16th to endNight
1212237%77%
1800
May1st to 15thNight
1212347%75%
1661
16th to endNight
1112336%77%
1684
June1st to 15thNight
1112246%78%
1458
16th to endNight
11388%
1440
July1st to 15thNight
111112235%78%
1440
16th to endNight
11111224476%
1637
August1st to 15thNight
11122384%
1800
16th to endNight
111112385%
1910
September1st to 15thNight
111223381%
1824
16th to endNight
1112486%
1980
October1st to 15thNight
111211235%75%
2013
16th to endNight
112211335%76%
2355
November1st to 15thNight
111222337%71%
2470
16th to endNight
1112323348%66%
2535
December1st to 15thNight
23342335%9%61%
2366
16th to endNight
331342445%8%57%
2661

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
16%412%26%26%13%
1432
16th to endDay
23%311%21%22%17%
1777
February1st to 15thDay
18%211%25%26%14%
1751
16th to endDay
22%311%26%27%8%
1579
March1st to 15thDay
16%312%27%23%16%
1800
16th to endDay
17%413%27%23%13%
2215
April1st to 15thDay
17%38%26%29%13%
2149
16th to endDay
10%210%23%36%17%
2160
May1st to 15thDay
10%17%21%32%26%
2289
16th to endDay
13%25%19%41%18%
2432
June1st to 15thDay
8%15%12%28%43%
2499
16th to endDay
6%2417%69%
2520
July1st to 15thDay
10%147%15%60%
2371
16th to endDay
14%249%21%46%
2368
August1st to 15thDay
8%126%19%61%
2146
16th to endDay
7%135%27%55%
2292
September1st to 15thDay
8%148%23%52%
2136
16th to endDay
6%119%38%42%
1980
October1st to 15thDay
11%1415%32%33%
1944
16th to endDay
13%2315%32%34%
1866
November1st to 15thDay
12%28%20%36%19%
1719
16th to endDay
15%37%21%32%20%
1755
December1st to 15thDay
18%312%25%26%13%
1630
16th to endDay
22%6%13%25%19%13%
1560
January1st to 15thNight
19%311%24%28%13%
2506
16th to endNight
22%29%21%25%17%
2442
February1st to 15thNight
19%313%22%24%16%
2112
16th to endNight
18%312%26%29%10%
1895
March1st to 15thNight
17%312%25%23%17%
2160
16th to endNight
16%313%31%24%9%
2007
April1st to 15thNight
15%39%30%29%11%
1799
16th to endNight
9%27%32%35%13%
1800
May1st to 15thNight
8%27%25%38%18%
1662
16th to endNight
8%28%22%40%16%
1685
June1st to 15thNight
5%26%16%32%36%
1458
16th to endNight
427%22%62%
1440
July1st to 15thNight
8%238%17%60%
1360
16th to endNight
11%248%24%47%
1531
August1st to 15thNight
7%129%22%57%
1790
16th to endNight
6%16%34%50%
1910
September1st to 15thNight
8%138%25%52%
1824
16th to endNight
4210%38%42%
1980
October1st to 15thNight
11%15%14%32%33%
2013
16th to endNight
10%1415%34%33%
2355
November1st to 15thNight
12%27%22%33%20%
2470
16th to endNight
14%29%21%30%21%
2535
December1st to 15thNight
19%411%24%28%12%
2366
16th to endNight
23%5%11%27%18%13%
2661

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
18%16%46%10%6%1
60
16th to endDay
15%18%34%22%7%2
249
February1st to 15thDay
11%18%33%27%8%1
266
16th to endDay
13%24%35%20%5%
238
March1st to 15thDay
11%22%33%20%10%1
270
16th to endDay
13%26%33%20%5%
288
April1st to 15thDay
14%30%31%15%6%1
269
16th to endDay
9%34%37%15%11
270
May1st to 15thDay
426%39%21%5%2
288
16th to endDay
8%24%31%27%5%2
330
June1st to 15thDay
6%17%41%26%6%1
315
16th to endDay
116%34%33%10%2
315
July1st to 15thDay
25%32%41%12%4
305
16th to endDay
3431%43%12%4
327
August1st to 15thDay
47%38%34%11%3
315
16th to endDay
15%31%41%14%5%
332
September1st to 15thDay
27%35%44%9%
315
16th to endDay
310%35%36%12%1
315
October1st to 15thDay
6%15%39%30%7%
315
16th to endDay
8%10%32%34%12%2
282
November1st to 15thDay
9%8%22%31%21%6%
135
16th to endDay
11%7%24%37%17%1
135
December1st to 15thDay
312%41%30%11%
94
16th to endDay
16%19%25%30%7%1
68
January1st to 15thNight
6%6%22%30%22%11%
720
16th to endNight
7%9%23%30%21%6%
768
February1st to 15thNight
38%29%28%20%8%
704
16th to endNight
6%11%30%28%17%5%
632
March1st to 15thNight
312%32%28%17%5%
720
16th to endNight
414%31%26%17%3
768
April1st to 15thNight
418%33%25%14%3
719
16th to endNight
315%33%24%19%3
720
May1st to 15thNight
213%37%29%13%3
582
16th to endNight
317%29%31%17%1
563
June1st to 15thNight
6%34%41%14%1
378
16th to endNight
1234%40%19%1
360
July1st to 15thNight
2114%44%35%2
340
16th to endNight
19%46%39%2
501
August1st to 15thNight
114%41%36%5%
717
16th to endNight
1111%32%44%10%
764
September1st to 15thNight
19%34%44%9%
720
16th to endNight
416%27%38%12%
716
October1st to 15thNight
25%23%35%23%9%
720
16th to endNight
35%18%27%29%15%
768
November1st to 15thNight
17%21%28%28%12%
760
16th to endNight
36%19%34%26%9%
780
December1st to 15thNight
5%8%23%32%22%7%
728
16th to endNight
8%8%30%26%21%5%
768
Page generated at 2017-12-03 08:16:35. Version ac04

Copyright 2017 A. Danko


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