Queen Valley
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Queen Valley clear sky chart from 2005-11-06 to 2024-01-14.

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
73%
23991
35%
74358
31%
23943
79%
23943
52%
35521

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
66%
759
32%
2457
30%
756
73%
756
44%
1229
January11th to 20thNight
62%
736
36%
2391
33%
736
71%
736
47%
1144
January21st to endNight
58%
792
35%
2574
31%
792
69%
792
39%
1346
February1st to 10thNight
65%
720
36%
2300
31%
720
76%
720
51%
1064
February11th to 20thNight
60%
700
32%
2099
27%
700
69%
700
44%
1108
February21st to endNight
59%
592
35%
1722
31%
592
67%
592
46%
907
March1st to 10thNight
60%
720
37%
1980
28%
720
70%
720
53%
1001
March11th to 20thNight
68%
720
37%
1980
30%
720
75%
720
55%
1004
March21st to endNight
68%
792
37%
2178
27%
792
75%
792
57%
1077
April1st to 10thNight
73%
720
36%
1980
25%
720
80%
720
61%
943
April11th to 20thNight
68%
579
40%
1823
33%
579
77%
579
63%
760
April21st to endNight
75%
540
46%
1707
39%
540
84%
540
70%
666
May1st to 10thNight
76%
540
42%
1620
36%
540
82%
540
68%
679
May11th to 20thNight
80%
531
40%
1594
34%
531
83%
531
68%
673
May21st to endNight
82%
582
41%
1746
35%
582
85%
582
77%
683
June1st to 10thNight
85%
540
36%
1620
32%
540
86%
540
69%
678
June11th to 20thNight
91%
540
40%
1620
34%
540
92%
540
83%
607
June21st to endNight
87%
540
32%
1620
29%
540
87%
540
64%
714
July1st to 10thNight
83%
525
25%
1575
22%
525
83%
525
46%
819
July11th to 20thNight
85%
522
23%
1566
19%
522
85%
522
42%
833
July21st to endNight
78%
591
22%
1674
18%
558
77%
558
33%
1015
August1st to 10thNight
87%
537
26%
1602
24%
534
87%
534
47%
822
August11th to 20thNight
81%
534
32%
1602
29%
534
81%
534
41%
881
August21st to endNight
83%
643
31%
1987
30%
643
84%
643
43%
1042
September1st to 10thNight
81%
720
33%
1980
30%
720
82%
720
48%
1076
September11th to 20thNight
83%
720
41%
1980
34%
720
85%
720
62%
946
September21st to endNight
81%
720
39%
1980
30%
720
85%
720
60%
952
October1st to 10thNight
77%
720
38%
2042
31%
720
82%
720
60%
970
October11th to 20thNight
82%
720
44%
2160
39%
720
87%
720
73%
878
October21st to endNight
78%
792
46%
2376
38%
792
85%
792
72%
968
November1st to 10thNight
76%
740
43%
2220
37%
740
83%
740
63%
974
November11th to 20thNight
75%
760
41%
2370
37%
760
82%
760
59%
1043
November21st to endNight
65%
760
38%
2470
34%
760
74%
760
49%
1166
December1st to 10thNight
64%
760
37%
2470
36%
760
71%
760
46%
1181
December11th to 20thNight
62%
759
32%
2948
33%
758
70%
758
32%
1610
December21st to endNight
63%
825
23%
4345
33%
817
68%
817
26%
2062

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
4313323346%67%
74969
Night
5%313323446%65%
74833
TransparencyDay
18%36%12%24%37%
74696
Night
19%35%12%23%37%
74628
SeeingDay
5%5%17%34%28%11%
13787
Night
6%213%41%33%5%
24010

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
7%424323346%62%
1708
11th to 20thDay
8%413323335%65%
1647
21st to endDay
8%413323346%62%
1782
February1st to 10thDay
5%42321345%5%65%
1656
11th to 20thDay
10%414423445%59%
1750
21st to endDay
8%423423346%61%
1533
March1st to 10thDay
7%41342445%6%59%
1980
11th to 20thDay
6%413323346%64%
1980
21st to endDay
5%324323335%68%
2178
April1st to 10thDay
2212323247%71%
1980
11th to 20thDay
2212222235%77%
2084
21st to endDay
2211213236%78%
2249
May1st to 10thDay
1212223335%77%
2340
11th to 20thDay
2112223246%77%
2301
21st to endDay
211211122286%
2530
June1st to 10thDay
1212113336%78%
2340
11th to 20thDay
11121112387%
2340
21st to endDay
2112322345%76%
2340
July1st to 10thDay
23233245%5%7%63%
2340
11th to 20thDay
33145%36%7%8%11%49%
2340
21st to endDay
5%325%5%46%6%8%13%42%
2545
August1st to 10thDay
43234345%6%9%57%
2328
11th to 20thDay
33244346%8%10%53%
2299
21st to endDay
32234345%6%9%58%
2363
September1st to 10thDay
431342445%7%63%
1980
11th to 20thDay
3112122345%77%
1980
21st to endDay
3212323335%75%
1980
October1st to 10thDay
3212323445%72%
1917
11th to 20thDay
211111223483%
1800
21st to endDay
2212223335%78%
1980
November1st to 10thDay
3211223247%73%
1859
11th to 20thDay
222222334473%
1805
21st to endDay
6%415%323436%64%
1710
December1st to 10thDay
8%413434446%61%
1710
11th to 20thDay
7%6%26%42346%7%52%
2169
21st to endDay
12%5%25%423446%54%
3146
January1st to 10thNight
8%32342445%6%59%
2457
11th to 20thNight
7%31332334466%
2391
21st to endNight
10%5%24323445%59%
2574
February1st to 10thNight
6%313422346%67%
2300
11th to 20thNight
9%5%23324436%59%
2098
21st to endNight
9%424323446%59%
1722
March1st to 10thNight
6%42331446%6%62%
1980
11th to 20thNight
8%312322345%67%
1980
21st to endNight
5%31332245%7%65%
2178
April1st to 10thNight
3212224346%70%
1980
11th to 20thNight
321231343476%
1823
21st to endNight
221212235%79%
1707
May1st to 10thNight
2211212346%76%
1620
11th to 20thNight
1212212335%76%
1594
21st to endNight
211111122386%
1746
June1st to 10thNight
2212212326%76%
1620
11th to 20thNight
111123486%
1620
21st to endNight
2112223446%73%
1620
July1st to 10thNight
22245%35%45%9%58%
1620
11th to 20thNight
13135%37%8%9%14%47%
1620
21st to endNight
4426%5%47%8%9%14%36%
1773
August1st to 10thNight
1324435%6%9%11%54%
1611
11th to 20thNight
3325%5%46%5%7%10%51%
1602
21st to endNight
34135%36%6%7%10%54%
1987
September1st to 10thNight
432333447%8%58%
1980
11th to 20thNight
3122322245%73%
1980
21st to endNight
2213422445%71%
1980
October1st to 10thNight
3212323346%70%
2042
11th to 20thNight
311111222481%
2160
21st to endNight
221211223481%
2376
November1st to 10thNight
4213212345%72%
2220
11th to 20thNight
2213312335%74%
2370
21st to endNight
7%213423346%65%
2470
December1st to 10thNight
8%31332335%7%62%
2470
11th to 20thNight
10%5%36%424446%52%
3041
21st to endNight
11%5%234345%4456%
4521

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
24%36%16%29%23%
1709
11th to 20thDay
22%35%11%28%30%
1647
21st to endDay
23%3415%27%28%
1782
February1st to 10thDay
20%35%16%21%36%
1656
11th to 20thDay
27%35%13%24%28%
1760
21st to endDay
24%4413%27%29%
1533
March1st to 10thDay
23%2410%29%32%
1980
11th to 20thDay
20%3410%26%36%
1980
21st to endDay
20%3310%33%32%
2178
April1st to 10thDay
14%1310%35%37%
1980
11th to 20thDay
13%137%26%49%
2087
21st to endDay
9%239%26%50%
2249
May1st to 10thDay
11%238%24%51%
2340
11th to 20thDay
10%339%24%51%
2304
21st to endDay
8%115%23%62%
2530
June1st to 10thDay
10%225%21%61%
2340
11th to 20thDay
6%11311%78%
2340
21st to endDay
11%248%18%57%
2340
July1st to 10thDay
19%5%7%12%20%38%
2276
11th to 20thDay
24%8%16%23%19%11%
2271
21st to endDay
29%8%18%21%15%8%
2404
August1st to 10thDay
23%6%11%18%16%27%
2313
11th to 20thDay
23%7%12%19%21%18%
2299
21st to endDay
20%6%10%17%27%20%
2363
September1st to 10thDay
21%48%16%23%28%
1980
11th to 20thDay
10%25%10%31%42%
1980
21st to endDay
13%349%25%47%
1980
October1st to 10thDay
15%3413%24%41%
1917
11th to 20thDay
8%146%26%55%
1800
21st to endDay
11%249%26%47%
1980
November1st to 10thDay
12%2313%34%36%
1859
11th to 20thDay
15%2411%26%42%
1805
21st to endDay
22%35%12%23%35%
1710
December1st to 10thDay
24%35%15%24%29%
1710
11th to 20thDay
29%47%18%23%19%
2168
21st to endDay
31%5%417%27%16%
3146
January1st to 10thNight
24%45%13%31%24%
2457
11th to 20thNight
22%3411%29%31%
2391
21st to endNight
28%35%11%27%26%
2574
February1st to 10thNight
20%35%12%23%38%
2300
11th to 20thNight
26%35%14%23%28%
2099
21st to endNight
24%45%10%26%32%
1722
March1st to 10thNight
20%35%11%26%35%
1980
11th to 20thNight
19%3311%25%39%
1980
21st to endNight
18%35%11%34%30%
2178
April1st to 10thNight
16%229%31%39%
1980
11th to 20thNight
13%238%26%49%
1823
21st to endNight
9%239%25%53%
1707
May1st to 10thNight
11%239%25%49%
1620
11th to 20thNight
12%248%21%54%
1595
21st to endNight
7%116%18%66%
1746
June1st to 10thNight
11%12419%62%
1620
11th to 20thNight
5%12313%76%
1620
21st to endNight
12%347%12%61%
1620
July1st to 10thNight
22%5%7%12%16%37%
1575
11th to 20thNight
21%9%16%21%20%12%
1566
21st to endNight
32%9%17%20%14%8%
1674
August1st to 10thNight
19%8%13%19%13%28%
1602
11th to 20thNight
25%7%12%18%18%20%
1602
21st to endNight
23%6%9%17%23%21%
1987
September1st to 10thNight
23%5%9%18%19%26%
1980
11th to 20thNight
15%349%26%44%
1980
21st to endNight
15%449%23%46%
1980
October1st to 10thNight
15%46%13%21%42%
2042
11th to 20thNight
9%228%23%56%
2160
21st to endNight
9%2310%24%52%
2376
November1st to 10thNight
14%1310%30%41%
2220
11th to 20thNight
15%2312%24%44%
2370
21st to endNight
21%2410%28%35%
2470
December1st to 10thNight
23%25%15%23%31%
2470
11th to 20thNight
32%36%15%24%21%
3041
21st to endNight
29%5%6%16%25%19%
4521

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
12%421%41%19%2
270
11th to 20thDay
14%418%37%22%4
249
21st to endDay
6%7%22%41%21%4
264
February1st to 10thDay
8%7%19%39%23%4
276
11th to 20thDay
13%7%28%34%16%1
415
21st to endDay
12%8%29%37%13%1
346
March1st to 10thDay
7%13%29%34%14%2
420
11th to 20thDay
8%9%26%32%23%3
420
21st to endDay
6%11%31%37%14%2
462
April1st to 10thDay
39%26%37%18%7%
420
11th to 20thDay
410%29%37%15%5%
412
21st to endDay
211%26%32%19%9%
420
May1st to 10thDay
39%25%32%24%7%
423
11th to 20thDay
2425%38%22%9%
448
21st to endDay
17%24%37%25%6%
485
June1st to 10thDay
3217%35%33%10%
450
11th to 20thDay
2218%37%30%11%
450
21st to endDay
219%42%36%9%
450
July1st to 10thDay
216%34%38%19%
446
11th to 20thDay
41426%39%27%
444
21st to endDay
41221%43%28%
487
August1st to 10thDay
31224%45%26%
447
11th to 20thDay
31226%41%27%
437
21st to endDay
21319%44%31%
495
September1st to 10thDay
6%17%29%40%18%
450
11th to 20thDay
427%30%42%14%
450
21st to endDay
3314%34%31%14%
450
October1st to 10thDay
4416%36%32%9%
387
11th to 20thDay
4314%33%37%10%
270
21st to endDay
2314%38%32%10%
297
November1st to 10thDay
5%415%39%31%5%
270
11th to 20thDay
4316%42%30%4
270
21st to endDay
7%6%21%39%23%4
270
December1st to 10thDay
10%416%42%25%3
270
11th to 20thDay
7%324%42%21%3
270
21st to endDay
16%6%23%32%19%3
297
January1st to 10thNight
10%217%48%20%3
760
11th to 20thNight
8%320%42%24%4
736
21st to endNight
13%320%42%19%3
792
February1st to 10thNight
8%219%42%26%3
720
11th to 20thNight
11%320%47%19%1
704
21st to endNight
8%422%45%18%3
592
March1st to 10thNight
6%424%48%17%1
720
11th to 20thNight
9%215%41%26%7%
720
21st to endNight
5%318%45%27%3
792
April1st to 10thNight
3315%52%24%3
720
11th to 20thNight
3322%47%24%1
579
21st to endNight
3317%50%23%4
540
May1st to 10thNight
2216%48%28%3
540
11th to 20thNight
2212%51%29%4
531
21st to endNight
3211%49%31%4
584
June1st to 10thNight
118%46%41%3
540
11th to 20thNight
16%51%39%3
540
21st to endNight
115%36%51%5%
540
July1st to 10thNight
31431%55%6%
525
11th to 20thNight
12320%66%8%
522
21st to endNight
5%1315%63%14%
591
August1st to 10thNight
2217%67%12%
537
11th to 20thNight
41321%62%9%
534
21st to endNight
41220%62%11%
643
September1st to 10thNight
5%2427%52%10%
720
11th to 20thNight
317%39%43%7%
720
21st to endNight
228%42%38%8%
720
October1st to 10thNight
5%211%46%34%3
720
11th to 20thNight
3111%47%32%5%
720
21st to endNight
3115%41%32%8%
792
November1st to 10thNight
5%212%47%29%5%
740
11th to 20thNight
3214%48%30%3
760
21st to endNight
8%219%42%26%4
760
December1st to 10thNight
9%318%40%28%2
760
11th to 20thNight
12%316%45%22%2
760
21st to endNight
12%115%48%20%4
836
Page generated at 2024-01-11 11:32:01. Version ac07

Copyright 2024 Attilla Danko


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