Quail Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Quail Creek clear sky chart from 2005-11-06 to 2024-01-16.

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%
23993
35%
74350
30%
23945
79%
23945
51%
35581

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
69%
758
33%
2457
31%
756
76%
756
48%
1180
January11th to 20thNight
68%
740
37%
2405
33%
740
78%
740
52%
1098
January21st to endNight
61%
792
36%
2574
32%
792
72%
792
42%
1304
February1st to 10thNight
71%
720
36%
2286
36%
720
78%
720
53%
1058
February11th to 20thNight
58%
700
33%
2099
25%
700
70%
700
46%
1076
February21st to endNight
58%
592
39%
1680
30%
592
69%
592
51%
849
March1st to 10thNight
58%
720
38%
1980
25%
720
70%
720
53%
1007
March11th to 20thNight
66%
720
38%
1980
27%
720
74%
720
57%
980
March21st to endNight
67%
792
37%
2178
25%
792
76%
792
57%
1071
April1st to 10thNight
68%
720
38%
1980
26%
720
77%
720
65%
913
April11th to 20thNight
62%
579
40%
1823
30%
579
75%
579
60%
775
April21st to endNight
70%
540
46%
1793
39%
540
81%
540
70%
670
May1st to 10thNight
69%
540
42%
1620
31%
540
79%
540
68%
666
May11th to 20thNight
76%
531
42%
1594
34%
531
82%
531
73%
642
May21st to endNight
77%
582
44%
1746
34%
582
84%
582
80%
662
June1st to 10thNight
83%
540
37%
1620
32%
540
84%
540
66%
687
June11th to 20thNight
84%
540
38%
1620
31%
540
87%
540
78%
627
June21st to endNight
83%
540
28%
1620
24%
540
84%
540
56%
755
July1st to 10thNight
83%
525
22%
1575
18%
525
83%
525
42%
841
July11th to 20thNight
80%
522
16%
1566
14%
522
80%
522
27%
1001
July21st to endNight
78%
591
14%
1674
12%
558
77%
558
25%
1118
August1st to 10thNight
84%
537
21%
1602
20%
534
84%
534
39%
891
August11th to 20thNight
81%
534
25%
1609
24%
534
81%
534
36%
919
August21st to endNight
82%
640
25%
2026
26%
640
82%
640
35%
1163
September1st to 10thNight
79%
720
27%
1980
25%
720
79%
720
41%
1156
September11th to 20thNight
86%
720
40%
1980
34%
720
88%
720
59%
978
September21st to endNight
80%
720
37%
1980
27%
720
85%
720
61%
964
October1st to 10thNight
79%
720
40%
2052
31%
720
84%
720
66%
940
October11th to 20thNight
80%
720
43%
2160
34%
720
87%
720
69%
904
October21st to endNight
82%
792
45%
2376
39%
792
87%
792
73%
966
November1st to 10thNight
78%
740
45%
2220
38%
740
85%
740
68%
938
November11th to 20thNight
77%
760
42%
2281
36%
760
83%
760
62%
1006
November21st to endNight
63%
760
37%
2470
32%
760
71%
760
48%
1184
December1st to 10thNight
69%
760
37%
2470
36%
760
74%
760
48%
1173
December11th to 20thNight
63%
760
32%
2942
31%
759
71%
759
34%
1556
December21st to endNight
61%
826
23%
4332
32%
817
69%
817
30%
1863

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
321342445%6%65%
74990
Night
321332345%7%67%
74844
TransparencyDay
21%47%11%25%32%
74717
Night
19%47%12%26%32%
74639
SeeingDay
47%20%33%26%11%
13796
Night
3316%41%32%5%
24011

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
332432445%8%61%
1708
11th to 20thDay
431232445%7%64%
1665
21st to endDay
4413323346%66%
1782
February1st to 10thDay
4312313445%68%
1670
11th to 20thDay
5%424325%446%61%
1750
21st to endDay
5%313322236%68%
1574
March1st to 10thDay
3324324447%64%
1980
11th to 20thDay
4312323346%69%
1980
21st to endDay
2212223335%73%
2178
April1st to 10thDay
112223347%74%
1980
11th to 20thDay
321221223480%
2085
21st to endDay
1112212125%82%
2163
May1st to 10thDay
21222223480%
2340
11th to 20thDay
1112212235%79%
2301
21st to endDay
111211212287%
2530
June1st to 10thDay
2211222337%76%
2340
11th to 20thDay
11111223483%
2340
21st to endDay
2214424446%66%
2340
July1st to 10thDay
33247%48%6%7%8%48%
2340
11th to 20thDay
4426%8%5%8%8%9%11%34%
2340
21st to endDay
7%5%37%8%5%8%8%8%11%29%
2545
August1st to 10thDay
5%4246%47%7%9%10%42%
2328
11th to 20thDay
4425%6%48%7%7%10%42%
2291
21st to endDay
32246%48%7%6%10%48%
2324
September1st to 10thDay
6%426%6%45%6%6%7%49%
1980
11th to 20thDay
321342445%7%66%
1980
21st to endDay
311322345%6%70%
1980
October1st to 10thDay
1112223446%73%
1906
11th to 20thDay
2112212235%80%
1800
21st to endDay
1111313246%78%
1980
November1st to 10thDay
111122335%6%75%
1859
11th to 20thDay
2212223345%73%
1896
21st to endDay
4313325%445%66%
1710
December1st to 10thDay
43134235%5%7%63%
1710
11th to 20thDay
5%5%35%435%46%7%54%
2169
21st to endDay
5%41442345%6%61%
3146
January1st to 10thNight
431332345%6%65%
2457
11th to 20thNight
4323213346%69%
2405
21st to endNight
5%32442445%5%62%
2574
February1st to 10thNight
3313323345%69%
2286
11th to 20thNight
4423333446%64%
2098
21st to endNight
3314323347%66%
1680
March1st to 10thNight
321332435%8%65%
1980
11th to 20thNight
3213322346%71%
1980
21st to endNight
321232345%6%68%
2178
April1st to 10thNight
1212322345%75%
1980
11th to 20thNight
121222223378%
1823
21st to endNight
211121222483%
1793
May1st to 10thNight
111212335%80%
1620
11th to 20thNight
12212346%80%
1594
21st to endNight
1111112388%
1746
June1st to 10thNight
3112212336%76%
1620
11th to 20thNight
1111211136%82%
1620
21st to endNight
2223323446%69%
1620
July1st to 10thNight
12245%35%5%7%9%56%
1620
11th to 20thNight
33246%47%8%11%15%37%
1620
21st to endNight
3426%7%5%6%9%11%17%31%
1773
August1st to 10thNight
2225%435%6%7%11%54%
1611
11th to 20thNight
43245%45%5%7%13%48%
1609
21st to endNight
4324445%7%8%11%48%
2026
September1st to 10thNight
5%4244246%6%9%53%
1980
11th to 20thNight
2213322345%71%
1980
21st to endNight
2213323346%70%
1980
October1st to 10thNight
1112222345%75%
2052
11th to 20thNight
1112212235%80%
2160
21st to endNight
111212235%82%
2376
November1st to 10thNight
2112212336%77%
2220
11th to 20thNight
222323346%74%
2281
21st to endNight
441342335%6%66%
2470
December1st to 10thNight
4314323347%66%
2470
11th to 20thNight
45%25%5%35%447%58%
3041
21st to endNight
5%4244345%5%5%60%
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
23%36%13%29%26%
1709
11th to 20thDay
22%46%9%28%31%
1665
21st to endDay
21%2416%28%28%
1782
February1st to 10thDay
21%2410%24%38%
1670
11th to 20thDay
26%35%13%24%29%
1760
21st to endDay
21%248%28%36%
1574
March1st to 10thDay
22%248%31%32%
1980
11th to 20thDay
20%248%28%37%
1980
21st to endDay
16%2310%37%32%
2178
April1st to 10thDay
13%247%36%38%
1980
11th to 20thDay
12%126%29%51%
2088
21st to endDay
9%137%32%48%
2163
May1st to 10thDay
12%137%23%55%
2340
11th to 20thDay
10%25%9%24%51%
2304
21st to endDay
8%12426%59%
2530
June1st to 10thDay
12%146%25%51%
2340
11th to 20thDay
8%14318%66%
2340
21st to endDay
20%46%8%19%43%
2340
July1st to 10thDay
31%7%10%14%16%21%
2276
11th to 20thDay
40%12%17%18%8%4
2271
21st to endDay
45%14%18%14%8%2
2404
August1st to 10thDay
34%12%14%14%17%9%
2313
11th to 20thDay
34%11%13%18%15%9%
2291
21st to endDay
31%9%14%19%16%11%
2324
September1st to 10thDay
34%6%10%15%16%19%
1980
11th to 20thDay
19%48%12%27%30%
1980
21st to endDay
17%39%11%32%28%
1980
October1st to 10thDay
14%38%13%28%34%
1906
11th to 20thDay
11%25%8%32%43%
1800
21st to endDay
11%2411%28%45%
1980
November1st to 10thDay
11%25%10%37%35%
1859
11th to 20thDay
16%2411%31%37%
1896
21st to endDay
23%25%12%25%33%
1710
December1st to 10thDay
22%36%15%29%26%
1710
11th to 20thDay
31%36%13%27%20%
2168
21st to endDay
24%36%12%37%18%
3146
January1st to 10thNight
22%37%13%31%24%
2457
11th to 20thNight
19%26%13%31%30%
2405
21st to endNight
25%45%12%29%24%
2574
February1st to 10thNight
19%2413%22%40%
2286
11th to 20thNight
23%36%13%25%29%
2099
21st to endNight
21%25%9%29%34%
1680
March1st to 10thNight
20%35%10%31%31%
1980
11th to 20thNight
18%2411%25%40%
1980
21st to endNight
18%26%12%35%27%
2178
April1st to 10thNight
14%1410%35%36%
1980
11th to 20thNight
14%137%27%47%
1823
21st to endNight
9%129%32%47%
1793
May1st to 10thNight
10%238%25%51%
1620
11th to 20thNight
8%25%9%26%50%
1595
21st to endNight
6%115%29%57%
1746
June1st to 10thNight
12%235%25%53%
1620
11th to 20thNight
8%4418%66%
1620
21st to endNight
17%38%6%19%47%
1620
July1st to 10thNight
23%8%14%16%14%25%
1575
11th to 20thNight
31%15%18%21%11%4
1566
21st to endNight
35%15%24%17%8%2
1674
August1st to 10thNight
23%11%15%22%18%12%
1602
11th to 20thNight
27%9%18%19%18%9%
1609
21st to endNight
28%9%15%18%20%11%
2026
September1st to 10thNight
27%7%12%21%17%17%
1980
11th to 20thNight
16%45%15%30%30%
1980
21st to endNight
15%37%14%33%27%
1980
October1st to 10thNight
12%47%16%26%35%
2052
11th to 20thNight
9%3412%27%44%
2160
21st to endNight
9%15%11%29%45%
2376
November1st to 10thNight
11%2414%36%34%
2220
11th to 20thNight
14%25%13%30%36%
2281
21st to endNight
22%35%11%29%30%
2470
December1st to 10thNight
21%36%17%27%27%
2470
11th to 20thNight
29%36%13%27%21%
3041
21st to endNight
26%37%11%31%22%
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
7%8%25%38%20%1
270
11th to 20thDay
9%420%43%20%4
255
21st to endDay
47%27%39%19%4
264
February1st to 10thDay
38%26%36%22%4
290
11th to 20thDay
9%16%31%32%12%
415
21st to endDay
10%14%38%29%9%1
346
March1st to 10thDay
5%15%32%34%11%2
420
11th to 20thDay
5%14%28%30%17%7%
420
21st to endDay
418%33%29%13%3
462
April1st to 10thDay
211%30%30%19%7%
420
11th to 20thDay
412%32%29%19%4
412
21st to endDay
213%29%30%18%7%
420
May1st to 10thDay
212%29%30%17%9%
423
11th to 20thDay
28%25%37%22%7%
448
21st to endDay
27%28%36%21%6%
485
June1st to 10thDay
3420%42%22%9%
450
11th to 20thDay
1419%39%26%11%
450
21st to endDay
2214%39%33%10%
450
July1st to 10thDay
217%33%39%18%
446
11th to 20thDay
5%15%25%41%24%
444
21st to endDay
8%15%19%40%27%
487
August1st to 10thDay
6%423%39%28%
447
11th to 20thDay
42425%39%25%
437
21st to endDay
41421%40%30%
495
September1st to 10thDay
8%29%34%32%14%
450
11th to 20thDay
417%34%40%14%
450
21st to endDay
5%316%30%32%13%
450
October1st to 10thDay
15%18%34%28%14%
376
11th to 20thDay
3113%33%36%13%
270
21st to endDay
2215%34%36%11%
297
November1st to 10thDay
46%17%38%28%6%
270
11th to 20thDay
3317%43%30%4
270
21st to endDay
5%7%27%36%21%3
270
December1st to 10thDay
6%5%21%36%28%3
270
11th to 20thDay
5%6%25%43%20%1
270
21st to endDay
9%8%27%35%18%4
297
January1st to 10thNight
6%319%48%23%3
760
11th to 20thNight
6%319%46%23%3
740
21st to endNight
6%422%44%22%2
792
February1st to 10thNight
4318%47%24%5%
720
11th to 20thNight
5%5%27%43%17%2
704
21st to endNight
6%6%28%42%17%1
592
March1st to 10thNight
35%30%43%17%1
720
11th to 20thNight
45%22%37%26%5%
720
21st to endNight
25%22%46%22%3
792
April1st to 10thNight
2323%48%22%2
720
11th to 20thNight
35%28%44%18%2
579
21st to endNight
2422%50%20%3
540
May1st to 10thNight
2323%46%24%1
540
11th to 20thNight
1218%48%29%3
531
21st to endNight
1219%48%29%1
584
June1st to 10thNight
319%51%34%2
540
11th to 20thNight
112%51%34%1
540
21st to endNight
217%41%44%5%
540
July1st to 10thNight
215%34%54%5%
525
11th to 20thNight
41321%63%8%
522
21st to endNight
4322%55%15%
591
August1st to 10thNight
2319%60%15%
537
11th to 20thNight
31322%60%10%
534
21st to endNight
41320%58%13%
640
September1st to 10thNight
5%16%28%49%11%
720
11th to 20thNight
316%37%47%7%
720
21st to endNight
2112%39%40%6%
720
October1st to 10thNight
215%44%34%4
720
11th to 20thNight
2115%46%30%6%
720
21st to endNight
1213%43%33%8%
792
November1st to 10thNight
2215%44%30%6%
740
11th to 20thNight
3115%45%33%3
760
21st to endNight
6%224%43%21%4
760
December1st to 10thNight
5%318%48%21%4
760
11th to 20thNight
6%6%21%47%18%2
760
21st to endNight
7%422%42%20%5%
836
Page generated at 2024-01-12 23:38:11. Version ac07

Copyright 2024 Attilla Danko


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