AVAC Kings Canyon Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the AVAC Kings Canyon Site clear sky chart from 2005-11-06 to 2024-01-10.

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
58%
24192
38%
74397
25%
24135
71%
24135
54%
33716

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 10thNight
46%
760
29%
2644
21%
756
61%
756
36%
1275
January11th to 20thNight
50%
720
36%
2380
24%
720
68%
720
45%
1115
January21st to endNight
43%
792
38%
2453
22%
792
63%
792
39%
1260
February1st to 10thNight
47%
720
37%
2160
23%
720
65%
720
46%
1050
February11th to 20thNight
47%
700
36%
2098
22%
700
66%
700
45%
1011
February21st to endNight
43%
592
34%
1776
22%
592
60%
592
44%
883
March1st to 10thNight
42%
720
29%
2160
17%
720
59%
720
37%
1160
March11th to 20thNight
46%
720
30%
2097
20%
720
59%
720
44%
1061
March21st to endNight
40%
792
35%
1980
13%
792
57%
792
47%
1055
April1st to 10thNight
39%
720
36%
1800
12%
720
55%
720
47%
958
April11th to 20thNight
40%
711
39%
1779
12%
711
56%
711
57%
871
April21st to endNight
42%
720
37%
1800
11%
720
55%
720
57%
870
May1st to 10thNight
42%
666
35%
1746
14%
666
53%
666
59%
815
May11th to 20thNight
47%
531
41%
1595
19%
531
62%
531
60%
659
May21st to endNight
46%
582
36%
1746
16%
582
61%
582
64%
696
June1st to 10thNight
53%
416
38%
1496
26%
416
69%
416
66%
524
June11th to 20thNight
65%
360
44%
1440
37%
360
82%
360
79%
410
June21st to endNight
68%
360
44%
1440
41%
360
82%
360
79%
421
July1st to 10thNight
87%
350
41%
1400
44%
350
92%
350
78%
413
July11th to 20thNight
89%
348
43%
1392
49%
348
91%
348
70%
445
July21st to endNight
86%
694
39%
1772
28%
656
88%
656
71%
792
August1st to 10thNight
77%
716
37%
1780
22%
712
80%
712
76%
823
August11th to 20thNight
88%
712
43%
1780
25%
712
90%
712
85%
782
August21st to endNight
86%
792
47%
1980
30%
792
89%
792
83%
878
September1st to 10thNight
82%
720
46%
1800
33%
720
86%
720
81%
808
September11th to 20thNight
78%
720
50%
1909
37%
720
87%
720
86%
781
September21st to endNight
73%
720
48%
1980
35%
720
86%
720
77%
814
October1st to 10thNight
64%
720
42%
1980
27%
720
80%
720
65%
881
October11th to 20thNight
67%
720
45%
2136
35%
720
81%
720
67%
884
October21st to endNight
62%
792
45%
2402
34%
792
79%
792
63%
1007
November1st to 10thNight
62%
740
39%
2405
31%
740
78%
740
60%
983
November11th to 20thNight
62%
760
40%
2470
32%
760
77%
760
56%
1055
November21st to endNight
55%
760
38%
2470
30%
760
69%
760
47%
1146
December1st to 10thNight
49%
760
36%
2470
23%
760
66%
760
43%
1183
December11th to 20thNight
48%
758
30%
2981
25%
758
63%
758
28%
1670
December21st to endNight
45%
828
21%
4700
23%
817
61%
817
22%
2277

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
3212323346%72%
74836
Night
3212323347%70%
74834
TransparencyDay
15%2417%29%32%
74557
Night
16%25%19%30%28%
74634
SeeingDay
6%14%32%31%14%3
14354
Night
48%26%37%20%3
24208

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 10thDay
5%5%14324448%59%
1511
11th to 20thDay
6%323423437%62%
1577
21st to endDay
7%5%25%423347%58%
1898
February1st to 10thDay
3423424346%64%
1800
11th to 20thDay
432332336%7%64%
1750
21st to endDay
5%43432446%6%60%
1480
March1st to 10thDay
4324436%6%7%9%52%
1800
11th to 20thDay
33144245%5%9%59%
1859
21st to endDay
331232445%9%62%
2376
April1st to 10thDay
431232335%8%65%
2160
11th to 20thDay
3112222346%73%
2129
21st to endDay
111222335%9%72%
2160
May1st to 10thDay
211222235%7%74%
2210
11th to 20thDay
1112222347%76%
2301
21st to endDay
2112313447%74%
2530
June1st to 10thDay
111212346%78%
2457
11th to 20thDay
1111235%87%
2520
21st to endDay
111111121288%
2520
July1st to 10thDay
111212235%84%
2520
11th to 20thDay
211221223481%
2520
21st to endDay
2112212246%77%
2435
August1st to 10thDay
111221222383%
2149
11th to 20thDay
1111222486%
2122
21st to endDay
111211225%84%
2376
September1st to 10thDay
11111123484%
2160
11th to 20thDay
111112488%
2049
21st to endDay
1111223484%
1980
October1st to 10thDay
2112212335%77%
1980
11th to 20thDay
11121332482%
1820
21st to endDay
1112221346%78%
1952
November1st to 10thDay
2111313346%75%
1674
11th to 20thDay
221232335%6%71%
1710
21st to endDay
431342445%8%64%
1710
December1st to 10thDay
4315%42346%8%61%
1710
11th to 20thDay
9%5%25%435%46%8%48%
2137
21st to endDay
9%7%25%6%345%5%8%46%
2794
January1st to 10thNight
6%4133245%6%9%56%
2644
11th to 20thNight
3313424449%63%
2380
21st to endNight
6%423423347%61%
2453
February1st to 10thNight
332332335%7%65%
2160
11th to 20thNight
422332345%8%65%
2098
21st to endNight
5%41332445%7%63%
1776
March1st to 10thNight
44245%345%7%10%52%
2160
11th to 20thNight
341342445%8%60%
2097
21st to endNight
321332445%9%64%
1980
April1st to 10thNight
422332445%8%66%
1800
11th to 20thNight
111222336%8%73%
1779
21st to endNight
121111235%9%72%
1800
May1st to 10thNight
111122237%10%70%
1746
11th to 20thNight
112212348%76%
1594
21st to endNight
111111225%6%79%
1746
June1st to 10thNight
12212237%79%
1496
11th to 20thNight
1111236%86%
1440
21st to endNight
111112290%
1440
July1st to 10thNight
1111122487%
1440
11th to 20thNight
11112335%82%
1440
21st to endNight
1112222335%77%
1876
August1st to 10thNight
211111233482%
1790
11th to 20thNight
1111123487%
1780
21st to endNight
1111123486%
1980
September1st to 10thNight
11121112487%
1800
11th to 20thNight
11123487%
1909
21st to endNight
1111223486%
1980
October1st to 10thNight
2111212335%79%
1980
11th to 20thNight
1112222335%79%
2136
21st to endNight
1112212246%78%
2402
November1st to 10thNight
1212213347%73%
2405
11th to 20thNight
221323446%72%
2470
21st to endNight
332332446%8%64%
2470
December1st to 10thNight
5%41242335%7%63%
2470
11th to 20thNight
8%6%35%435%5%6%9%48%
3055
21st to endNight
8%4245%35%5%7%9%48%
4862

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 10thDay
25%38%25%28%11%
1511
11th to 20thDay
24%36%20%28%19%
1577
21st to endDay
28%36%22%23%18%
1898
February1st to 10thDay
22%4421%28%22%
1800
11th to 20thDay
20%2420%36%18%
1760
21st to endDay
26%35%22%32%13%
1480
March1st to 10thDay
26%48%24%22%15%
1800
11th to 20thDay
23%37%24%26%17%
1859
21st to endDay
20%310%28%26%13%
2376
April1st to 10thDay
19%39%28%27%14%
2160
11th to 20thDay
13%28%25%32%19%
2132
21st to endDay
12%38%24%36%16%
2160
May1st to 10thDay
12%27%23%33%23%
2210
11th to 20thDay
10%3422%38%24%
2304
21st to endDay
12%3426%36%18%
2530
June1st to 10thDay
10%25%18%32%34%
2457
11th to 20thDay
41414%28%49%
2520
21st to endDay
7%11423%64%
2520
July1st to 10thDay
6%216%18%67%
2451
11th to 20thDay
10%1211%28%47%
2445
21st to endDay
11%2215%32%39%
2299
August1st to 10thDay
10%118%22%59%
2135
11th to 20thDay
6%25%31%56%
2122
21st to endDay
7%116%28%57%
2376
September1st to 10thDay
7%217%25%58%
2160
11th to 20thDay
5%1110%33%50%
2049
21st to endDay
7%219%39%42%
1980
October1st to 10thDay
12%2318%26%41%
1980
11th to 20thDay
10%2313%31%42%
1820
21st to endDay
10%2412%30%43%
1952
November1st to 10thDay
12%3419%36%27%
1674
11th to 20thDay
15%25%17%31%29%
1710
21st to endDay
20%35%18%28%26%
1710
December1st to 10thDay
23%36%21%27%20%
1710
11th to 20thDay
36%27%23%24%9%
2136
21st to endDay
37%35%26%21%8%
2794
January1st to 10thNight
25%47%23%29%13%
2644
11th to 20thNight
20%48%20%30%19%
2380
21st to endNight
26%27%19%26%20%
2453
February1st to 10thNight
21%36%19%27%25%
2160
11th to 20thNight
20%26%19%31%23%
2099
21st to endNight
21%47%23%29%16%
1776
March1st to 10thNight
26%47%24%22%16%
2160
11th to 20thNight
22%39%23%27%16%
2097
21st to endNight
20%210%32%25%11%
1980
April1st to 10thNight
19%39%32%23%15%
1800
11th to 20thNight
12%29%30%30%17%
1779
21st to endNight
11%37%28%39%12%
1800
May1st to 10thNight
11%38%27%35%17%
1746
11th to 20thNight
10%25%24%42%18%
1595
21st to endNight
8%29%30%36%14%
1746
June1st to 10thNight
9%16%22%32%29%
1496
11th to 20thNight
415%16%30%45%
1440
21st to endNight
5%116%28%59%
1440
July1st to 10thNight
5%117%24%62%
1400
11th to 20thNight
8%2313%29%45%
1392
21st to endNight
10%2317%32%37%
1772
August1st to 10thNight
9%119%28%52%
1780
11th to 20thNight
5%118%31%54%
1780
21st to endNight
6%216%34%51%
1980
September1st to 10thNight
7%116%32%53%
1800
11th to 20thNight
41211%36%46%
1909
21st to endNight
6%1110%40%42%
1980
October1st to 10thNight
11%2316%28%41%
1980
11th to 20thNight
10%2314%31%40%
2136
21st to endNight
11%2311%29%43%
2402
November1st to 10thNight
12%2419%35%28%
2405
11th to 20thNight
15%3415%33%31%
2470
21st to endNight
20%3420%26%27%
2470
December1st to 10thNight
23%25%19%27%24%
2470
11th to 20thNight
34%39%19%25%10%
3055
21st to endNight
32%36%29%22%8%
4862

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 10thDay
9%21%37%25%8%
178
11th to 20thDay
13%20%35%25%6%
297
21st to endDay
12%23%32%19%12%1
426
February1st to 10thDay
9%21%32%27%9%2
420
11th to 20thDay
12%26%31%20%7%2
415
21st to endDay
11%23%39%21%5%1
346
March1st to 10thDay
13%25%35%18%8%1
420
11th to 20thDay
9%22%35%24%7%3
420
21st to endDay
14%26%35%18%6%1
462
April1st to 10thDay
12%19%37%20%10%2
420
11th to 20thDay
9%28%35%18%6%3
412
21st to endDay
7%28%30%20%10%5%
420
May1st to 10thDay
7%19%36%25%11%2
423
11th to 20thDay
417%40%27%9%4
448
21st to endDay
5%17%37%26%12%4
485
June1st to 10thDay
49%36%31%15%4
450
11th to 20thDay
19%36%33%17%4
450
21st to endDay
26%37%34%16%4
450
July1st to 10thDay
231%47%17%2
446
11th to 20thDay
2123%43%27%5%
444
21st to endDay
220%46%26%6%
487
August1st to 10thDay
2329%47%14%5%
447
11th to 20thDay
2322%48%18%8%
437
21st to endDay
1227%43%21%6%
495
September1st to 10thDay
1331%40%20%6%
450
11th to 20thDay
19%35%34%17%4
450
21st to endDay
110%29%38%18%4
450
October1st to 10thDay
413%32%33%16%2
450
11th to 20thDay
411%30%35%17%2
450
21st to endDay
315%33%26%19%3
467
November1st to 10thDay
6%12%29%32%19%3
270
11th to 20thDay
7%9%31%34%15%4
270
21st to endDay
10%14%30%32%12%2
270
December1st to 10thDay
6%15%39%28%11%1
270
11th to 20thDay
7%18%32%29%14%1
261
21st to endDay
14%25%28%24%8%1
198
January1st to 10thNight
10%11%28%31%16%4
760
11th to 20thNight
7%9%29%38%15%3
720
21st to endNight
9%11%30%33%14%2
792
February1st to 10thNight
5%13%29%31%18%4
720
11th to 20thNight
7%12%30%30%15%5%
704
21st to endNight
8%10%36%33%11%2
592
March1st to 10thNight
7%12%34%34%11%2
720
11th to 20thNight
6%13%31%29%18%3
720
21st to endNight
7%16%33%30%11%2
792
April1st to 10thNight
7%16%35%28%13%2
720
11th to 20thNight
415%39%29%13%1
711
21st to endNight
318%35%27%14%3
720
May1st to 10thNight
214%40%31%12%2
666
11th to 20thNight
115%34%35%15%1
531
21st to endNight
313%37%33%14%1
584
June1st to 10thNight
7%38%45%10%
416
11th to 20thNight
5%28%50%16%1
360
21st to endNight
1228%46%23%1
360
July1st to 10thNight
1110%57%29%1
350
11th to 20thNight
16%59%32%2
348
21st to endNight
28%52%34%5%
694
August1st to 10thNight
2116%47%31%3
716
11th to 20thNight
18%45%39%6%
712
21st to endNight
110%43%38%7%
792
September1st to 10thNight
2112%41%37%6%
720
11th to 20thNight
119%45%29%5%
720
21st to endNight
15%19%40%29%6%
720
October1st to 10thNight
38%23%43%21%2
720
11th to 20thNight
26%23%41%23%6%
720
21st to endNight
27%26%35%22%8%
792
November1st to 10thNight
37%26%39%19%6%
740
11th to 20thNight
4426%40%21%6%
760
21st to endNight
5%7%28%36%19%4
760
December1st to 10thNight
8%9%30%33%16%3
760
11th to 20thNight
9%9%28%36%17%1
760
21st to endNight
9%11%30%34%12%2
836
Page generated at 2024-01-07 07:06:52. Version ac07

Copyright 2024 Attilla Danko


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