Rosamond Skypark
Clear Sky Chart
History

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

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
64%
24183
38%
74397
28%
24133
74%
24133
61%
32498

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
56%
756
30%
2646
26%
756
66%
756
43%
1262
January11th to 20thNight
62%
724
37%
2420
31%
724
74%
724
51%
1083
January21st to endNight
52%
792
41%
2420
29%
792
67%
792
49%
1170
February1st to 10thNight
57%
720
37%
2160
28%
720
70%
720
53%
1023
February11th to 20thNight
53%
700
39%
2098
27%
700
69%
700
54%
964
February21st to endNight
49%
592
35%
1776
26%
592
64%
592
50%
865
March1st to 10thNight
49%
720
31%
2160
22%
720
64%
720
46%
1073
March11th to 20thNight
53%
720
31%
2107
23%
720
65%
720
51%
1034
March21st to endNight
45%
792
37%
1980
15%
792
62%
792
58%
1020
April1st to 10thNight
45%
720
37%
1800
14%
720
61%
720
60%
918
April11th to 20thNight
46%
711
41%
1779
15%
711
60%
711
69%
835
April21st to endNight
47%
720
40%
1800
13%
720
61%
720
72%
827
May1st to 10thNight
47%
640
38%
1720
16%
640
58%
640
75%
727
May11th to 20thNight
52%
531
42%
1595
22%
531
66%
531
71%
625
May21st to endNight
48%
582
38%
1746
20%
582
62%
582
71%
667
June1st to 10thNight
61%
446
39%
1526
28%
446
74%
446
79%
508
June11th to 20thNight
64%
360
44%
1440
39%
360
80%
360
88%
391
June21st to endNight
73%
360
44%
1440
44%
360
84%
360
83%
409
July1st to 10thNight
90%
350
41%
1400
45%
350
94%
350
78%
413
July11th to 20thNight
89%
348
42%
1392
46%
348
92%
348
66%
459
July21st to endNight
87%
684
40%
1762
30%
646
88%
646
74%
771
August1st to 10thNight
81%
716
38%
1780
24%
712
82%
712
81%
795
August11th to 20thNight
89%
712
43%
1780
25%
712
91%
712
87%
771
August21st to endNight
88%
792
47%
1980
31%
792
90%
792
84%
864
September1st to 10thNight
84%
720
47%
1800
33%
720
88%
720
84%
790
September11th to 20thNight
81%
720
50%
1925
37%
720
89%
720
89%
768
September21st to endNight
76%
720
48%
1980
37%
720
88%
720
83%
788
October1st to 10thNight
70%
720
44%
1980
31%
720
85%
720
74%
850
October11th to 20thNight
71%
720
46%
2110
37%
720
84%
720
74%
847
October21st to endNight
69%
792
46%
2427
40%
792
82%
792
73%
947
November1st to 10thNight
70%
740
40%
2405
37%
740
82%
740
69%
932
November11th to 20thNight
74%
760
41%
2470
38%
760
83%
760
64%
997
November21st to endNight
64%
760
38%
2470
35%
760
73%
760
54%
1104
December1st to 10thNight
59%
760
37%
2470
29%
760
72%
760
48%
1156
December11th to 20thNight
59%
758
31%
2952
29%
758
70%
758
34%
1545
December21st to endNight
52%
825
20%
4701
27%
817
64%
817
25%
2300

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
2212212346%75%
74891
Night
2212212346%74%
74817
TransparencyDay
12%35%16%28%36%
74612
Night
13%36%19%30%30%
74617
SeeingDay
310%25%31%22%10%
14331
Night
3426%41%23%3
24206

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
6%31332346%9%59%
1519
11th to 20thDay
5%413324347%63%
1548
21st to endDay
5%414424347%61%
1930
February1st to 10thDay
3313324448%66%
1800
11th to 20thDay
421232335%7%69%
1750
21st to endDay
3314324347%66%
1480
March1st to 10thDay
331343447%9%59%
1800
11th to 20thDay
22133235%6%10%63%
1847
21st to endDay
221222346%8%69%
2376
April1st to 10thDay
321222335%7%71%
2160
11th to 20thDay
2211312235%78%
2129
21st to endDay
1111113347%77%
2160
May1st to 10thDay
1112112336%81%
2239
11th to 20thDay
111112236%82%
2301
21st to endDay
122212235%80%
2530
June1st to 10thDay
111212236%81%
2429
11th to 20thDay
1122490%
2520
21st to endDay
1111112389%
2520
July1st to 10thDay
1121123485%
2520
11th to 20thDay
221211223481%
2520
21st to endDay
2212212235%79%
2445
August1st to 10thDay
111221212485%
2149
11th to 20thDay
11111122487%
2122
21st to endDay
1111222485%
2376
September1st to 10thDay
11111133384%
2160
11th to 20thDay
11112390%
2034
21st to endDay
1111122487%
1980
October1st to 10thDay
1112221245%79%
1980
11th to 20thDay
11111232484%
1846
21st to endDay
1111112335%82%
1926
November1st to 10thDay
111212337%78%
1674
11th to 20thDay
1213223345%73%
1710
21st to endDay
3213323449%67%
1710
December1st to 10thDay
32143345%5%8%61%
1710
11th to 20thDay
6%5%345%36%6%6%7%51%
2169
21st to endDay
7%6%24435%6%7%8%47%
2822
January1st to 10thNight
5%31432345%9%61%
2646
11th to 20thNight
3212323348%67%
2420
21st to endNight
4424312247%66%
2420
February1st to 10thNight
3314323346%69%
2160
11th to 20thNight
4213223346%70%
2098
21st to endNight
4323323346%67%
1776
March1st to 10thNight
3314325%5%6%9%60%
2160
11th to 20thNight
331342345%8%65%
2107
21st to endNight
311321345%7%70%
1980
April1st to 10thNight
3212213347%72%
1800
11th to 20thNight
1112212237%78%
1779
21st to endNight
1111112236%80%
1800
May1st to 10thNight
1112348%79%
1720
11th to 20thNight
112112235%83%
1594
21st to endNight
111111223484%
1746
June1st to 10thNight
11211235%85%
1526
11th to 20thNight
12491%
1440
21st to endNight
11111111291%
1440
July1st to 10thNight
111222388%
1440
11th to 20thNight
1111112235%81%
1440
21st to endNight
2111222235%80%
1866
August1st to 10thNight
21111123485%
1790
11th to 20thNight
1111112389%
1780
21st to endNight
11111222387%
1980
September1st to 10thNight
11111112388%
1800
11th to 20thNight
121391%
1925
21st to endNight
1111112388%
1980
October1st to 10thNight
1111122245%81%
1980
11th to 20thNight
12211235%83%
2110
21st to endNight
1111112235%83%
2427
November1st to 10thNight
1112112236%78%
2405
11th to 20thNight
1211212337%76%
2470
21st to endNight
321232335%7%68%
2470
December1st to 10thNight
3423324347%67%
2470
11th to 20thNight
6%425%43446%9%54%
3041
21st to endNight
5%325%5%35%6%7%9%51%
4831

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%5%8%26%29%9%
1519
11th to 20thDay
23%48%21%29%16%
1548
21st to endDay
24%38%23%26%16%
1930
February1st to 10thDay
20%37%21%28%21%
1800
11th to 20thDay
15%36%21%36%19%
1760
21st to endDay
18%47%23%31%16%
1480
March1st to 10thDay
19%5%10%23%25%18%
1800
11th to 20thDay
17%410%23%27%19%
1847
21st to endDay
12%5%10%27%31%15%
2376
April1st to 10thDay
14%49%24%29%20%
2160
11th to 20thDay
11%26%22%36%23%
2132
21st to endDay
7%37%23%36%23%
2160
May1st to 10thDay
8%26%21%32%30%
2239
11th to 20thDay
7%25%17%39%30%
2304
21st to endDay
9%25%20%38%26%
2530
June1st to 10thDay
7%2415%30%42%
2429
11th to 20thDay
21312%24%58%
2520
21st to endDay
6%12318%71%
2520
July1st to 10thDay
6%216%16%70%
2451
11th to 20thDay
10%228%22%55%
2445
21st to endDay
11%1312%28%45%
2309
August1st to 10thDay
8%117%18%65%
2135
11th to 20thDay
5%216%25%61%
2122
21st to endDay
6%115%24%62%
2376
September1st to 10thDay
7%226%20%63%
2160
11th to 20thDay
4127%31%55%
2034
21st to endDay
5%118%35%49%
1980
October1st to 10thDay
10%2314%28%44%
1980
11th to 20thDay
7%2413%32%43%
1846
21st to endDay
7%3412%29%45%
1926
November1st to 10thDay
9%25%17%38%28%
1674
11th to 20thDay
15%35%17%33%27%
1710
21st to endDay
16%46%19%29%25%
1710
December1st to 10thDay
22%48%22%25%20%
1710
11th to 20thDay
31%6%9%20%25%9%
2168
21st to endDay
36%6%9%24%19%8%
2822
January1st to 10thNight
23%47%24%32%11%
2646
11th to 20thNight
18%48%23%29%19%
2420
21st to endNight
20%38%21%29%19%
2420
February1st to 10thNight
18%38%19%27%25%
2160
11th to 20thNight
17%26%19%31%25%
2099
21st to endNight
18%5%7%23%29%17%
1776
March1st to 10thNight
19%5%9%26%24%17%
2160
11th to 20thNight
19%49%22%28%18%
2107
21st to endNight
14%5%9%31%28%13%
1980
April1st to 10thNight
15%38%31%24%18%
1800
11th to 20thNight
9%27%30%34%18%
1779
21st to endNight
8%26%27%44%13%
1800
May1st to 10thNight
5%39%25%37%21%
1720
11th to 20thNight
7%25%19%47%21%
1595
21st to endNight
5%27%26%42%18%
1746
June1st to 10thNight
5%15%21%33%34%
1526
11th to 20thNight
21413%29%51%
1440
21st to endNight
412427%62%
1440
July1st to 10thNight
5%116%18%69%
1400
11th to 20thNight
9%2310%24%52%
1392
21st to endNight
9%2314%31%41%
1762
August1st to 10thNight
7%229%22%59%
1780
11th to 20thNight
4118%29%57%
1780
21st to endNight
5%115%29%58%
1980
September1st to 10thNight
6%126%27%59%
1800
11th to 20thNight
3129%37%49%
1925
21st to endNight
5%119%37%47%
1980
October1st to 10thNight
8%2414%28%44%
1980
11th to 20thNight
7%2313%32%42%
2110
21st to endNight
7%2411%28%48%
2427
November1st to 10thNight
10%2418%36%30%
2405
11th to 20thNight
11%25%16%33%32%
2470
21st to endNight
16%46%20%27%27%
2470
December1st to 10thNight
19%46%21%26%24%
2470
11th to 20thNight
25%7%11%21%25%10%
3041
21st to endNight
29%7%10%27%19%8%
4831

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
8%6%27%36%21%3
180
11th to 20thDay
10%13%22%23%24%8%
268
21st to endDay
7%14%24%27%21%6%
440
February1st to 10thDay
6%15%21%31%19%8%
420
11th to 20thDay
5%18%29%24%16%7%
415
21st to endDay
5%18%29%28%15%4
346
March1st to 10thDay
8%22%26%25%14%5%
420
11th to 20thDay
5%18%33%23%17%5%
420
21st to endDay
6%19%35%25%13%2
462
April1st to 10thDay
6%16%30%27%14%7%
420
11th to 20thDay
318%35%28%12%4
412
21st to endDay
220%30%24%13%11%
420
May1st to 10thDay
215%34%25%15%9%
423
11th to 20thDay
213%32%27%18%8%
448
21st to endDay
312%31%27%16%11%
485
June1st to 10thDay
28%29%31%19%12%
450
11th to 20thDay
6%27%31%23%13%
450
21st to endDay
1429%34%20%13%
450
July1st to 10thDay
222%43%22%12%
446
11th to 20thDay
212%42%30%14%
444
21st to endDay
211%41%25%19%
487
August1st to 10thDay
2221%41%23%11%
447
11th to 20thDay
2214%40%24%19%
437
21st to endDay
1116%41%27%15%
495
September1st to 10thDay
1219%33%30%15%
450
11th to 20thDay
15%28%30%25%13%
450
21st to endDay
6%22%29%29%14%
450
October1st to 10thDay
19%26%26%27%11%
450
11th to 20thDay
17%20%28%32%11%
450
21st to endDay
28%23%26%27%15%
441
November1st to 10thDay
19%20%30%27%13%
270
11th to 20thDay
27%17%37%28%9%
270
21st to endDay
39%21%29%30%9%
270
December1st to 10thDay
5%6%23%36%25%5%
270
11th to 20thDay
5%7%23%29%28%8%
270
21st to endDay
11%14%20%28%21%6%
205
January1st to 10thNight
7%427%38%20%3
760
11th to 20thNight
5%425%45%19%2
724
21st to endNight
7%5%31%38%18%2
792
February1st to 10thNight
45%30%36%22%3
720
11th to 20thNight
5%7%32%34%18%4
704
21st to endNight
5%6%36%38%13%2
592
March1st to 10thNight
410%33%36%16%1
720
11th to 20thNight
47%32%37%18%3
720
21st to endNight
49%39%34%13%1
792
April1st to 10thNight
5%7%41%30%16%2
720
11th to 20thNight
19%42%33%14%1
711
21st to endNight
29%40%31%16%2
720
May1st to 10thNight
16%45%35%12%1
640
11th to 20thNight
8%37%40%14%1
531
21st to endNight
112%38%38%11%
584
June1st to 10thNight
433%53%10%
446
11th to 20thNight
133%50%16%
360
21st to endNight
1123%57%18%
360
July1st to 10thNight
17%63%29%1
350
11th to 20thNight
215%57%34%1
348
21st to endNight
217%53%35%2
684
August1st to 10thNight
214%51%30%3
716
11th to 20thNight
17%49%39%5%
712
21st to endNight
18%45%40%5%
792
September1st to 10thNight
1111%41%42%4
720
11th to 20thNight
117%45%33%4
720
21st to endNight
219%40%34%5%
720
October1st to 10thNight
1323%43%28%3
720
11th to 20thNight
1323%39%30%5%
720
21st to endNight
1424%35%30%7%
792
November1st to 10thNight
2423%41%26%4
740
11th to 20thNight
2219%46%26%5%
760
21st to endNight
4325%40%26%2
760
December1st to 10thNight
6%427%37%23%2
760
11th to 20thNight
6%5%24%42%21%2
760
21st to endNight
7%6%30%38%17%2
836
Page generated at 2024-01-08 08:14:16. Version ac07

Copyright 2024 Attilla Danko


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