Sierra la Rana
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sierra la Rana clear sky chart from 2005-11-06 to 2024-01-15.

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
59%
23710
32%
74449
23%
23660
69%
23660
44%
37570

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
52%
756
37%
2268
21%
756
65%
756
44%
1151
January11th to 20thNight
51%
736
34%
2208
21%
736
64%
736
44%
1138
January21st to endNight
49%
792
39%
2376
23%
792
65%
792
44%
1213
February1st to 10thNight
53%
720
37%
2160
22%
720
67%
720
47%
1082
February11th to 20thNight
47%
702
28%
2098
15%
700
59%
700
40%
1125
February21st to endNight
38%
592
36%
1776
16%
592
56%
592
45%
877
March1st to 10thNight
47%
720
33%
2160
16%
720
61%
720
43%
1109
March11th to 20thNight
43%
720
29%
2080
15%
720
55%
720
41%
1141
March21st to endNight
43%
594
41%
1980
24%
594
63%
594
47%
909
April1st to 10thNight
45%
540
37%
1800
22%
540
64%
540
41%
891
April11th to 20thNight
38%
533
34%
1777
19%
533
59%
533
43%
848
April21st to endNight
46%
540
37%
1800
26%
540
67%
540
50%
797
May1st to 10thNight
49%
540
31%
1800
22%
540
66%
540
47%
836
May11th to 20thNight
55%
531
26%
1766
26%
531
62%
531
39%
915
May21st to endNight
53%
582
28%
1745
22%
582
64%
582
43%
918
June1st to 10thNight
65%
540
25%
1620
23%
540
71%
540
48%
821
June11th to 20thNight
62%
540
28%
1620
22%
540
71%
540
46%
851
June21st to endNight
74%
540
28%
1620
27%
540
77%
540
45%
842
July1st to 10thNight
75%
525
18%
1690
18%
525
77%
525
37%
945
July11th to 20thNight
81%
522
28%
1740
30%
522
85%
522
48%
834
July21st to endNight
81%
591
26%
1859
30%
558
84%
558
45%
912
August1st to 10thNight
85%
537
28%
1779
32%
534
88%
534
52%
805
August11th to 20thNight
81%
534
24%
1778
27%
534
83%
534
35%
987
August21st to endNight
80%
594
21%
1980
23%
594
81%
594
34%
1117
September1st to 10thNight
79%
540
24%
1800
26%
540
80%
540
37%
978
September11th to 20thNight
75%
540
25%
1926
28%
540
76%
540
31%
1079
September21st to endNight
75%
540
28%
1980
30%
540
77%
540
35%
1033
October1st to 10thNight
71%
540
31%
1980
32%
540
74%
540
41%
954
October11th to 20thNight
67%
615
36%
2055
28%
615
74%
615
42%
1020
October21st to endNight
66%
792
39%
2376
26%
792
74%
792
54%
1121
November1st to 10thNight
68%
808
38%
2288
24%
808
72%
808
55%
1125
November11th to 20thNight
66%
950
34%
2470
21%
950
71%
950
55%
1293
November21st to endNight
54%
950
37%
2470
19%
950
64%
950
48%
1344
December1st to 10thNight
59%
950
38%
2470
23%
950
66%
950
48%
1368
December11th to 20thNight
49%
950
37%
2889
18%
949
61%
949
42%
1533
December21st to endNight
49%
1014
27%
4265
19%
1003
62%
1003
41%
1658

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
43234345%6%7%59%
74745
Night
431332445%8%61%
75058
TransparencyDay
23%6%9%18%25%20%
74495
Night
21%5%9%19%25%20%
74830
SeeingDay
6%9%25%32%23%6%
13508
Night
6%5%25%42%20%2
23726

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%323323436%64%
1897
11th to 20thDay
5%423223446%66%
1840
21st to endDay
4424433345%65%
1980
February1st to 10thDay
33133246%46%64%
1800
11th to 20thDay
5%424323446%63%
1749
21st to endDay
331232346%9%66%
1480
March1st to 10thDay
35%24435%46%8%55%
1800
11th to 20thDay
5%5%2442435%7%59%
1876
21st to endDay
232232345%7%67%
2376
April1st to 10thDay
331332445%8%65%
2160
11th to 20thDay
331332445%6%66%
2131
21st to endDay
5%412223336%70%
2160
May1st to 10thDay
3313323447%67%
2160
11th to 20thDay
5%32332446%6%61%
2125
21st to endDay
41133245%6%9%63%
2531
June1st to 10thDay
12133345%7%9%63%
2340
11th to 20thDay
32133345%6%8%62%
2340
21st to endDay
4313435%7%8%9%53%
2340
July1st to 10thDay
7%425%6%5%7%7%8%9%40%
2212
11th to 20thDay
43145%37%6%8%9%50%
2160
21st to endDay
3325%6%47%7%9%10%45%
2349
August1st to 10thDay
32245%47%6%7%11%49%
2149
11th to 20thDay
6%6%37%8%5%7%8%6%9%36%
2123
21st to endDay
5%5%25%7%47%6%7%9%42%
2376
September1st to 10thDay
10%5%25%6%45%6%6%8%44%
2160
11th to 20thDay
10%425%6%45%7%7%8%42%
2032
21st to endDay
8%4244445%5%7%53%
1980
October1st to 10thDay
431342345%8%63%
1980
11th to 20thDay
7%413323335%65%
1900
21st to endDay
5%312222236%71%
1980
November1st to 10thDay
6%312212346%71%
1769
11th to 20thDay
35%2232345%5%68%
1710
21st to endDay
6%5%13323345%64%
1710
December1st to 10thDay
7%423223347%62%
1710
11th to 20thDay
1323435%5%6%8%61%
2161
21st to endDay
321232335%7%69%
3199
January1st to 10thNight
5%423423346%63%
2268
11th to 20thNight
6%423423447%62%
2208
21st to endNight
4424333347%62%
2376
February1st to 10thNight
341342445%6%63%
2160
11th to 20thNight
5%423425%5%46%59%
2098
21st to endNight
4423313446%66%
1776
March1st to 10thNight
441443445%9%58%
2160
11th to 20thNight
46%23424346%61%
2080
21st to endNight
231332345%5%67%
1980
April1st to 10thNight
5%42342446%7%61%
1800
11th to 20thNight
5%2123345%5%7%64%
1777
21st to endNight
331232335%6%70%
1800
May1st to 10thNight
4213324447%65%
1800
11th to 20thNight
6%313435%46%7%59%
1766
21st to endNight
33134345%6%9%60%
1745
June1st to 10thNight
32123347%7%11%57%
1620
11th to 20thNight
3213435%6%8%10%56%
1620
21st to endNight
32133246%8%10%57%
1620
July1st to 10thNight
33245%35%6%8%12%49%
1740
11th to 20thNight
321223447%11%61%
1800
21st to endNight
2113435%6%6%11%57%
1969
August1st to 10thNight
22113245%8%13%60%
1790
11th to 20thNight
33235%346%9%14%47%
1778
21st to endNight
4324436%6%8%11%49%
1980
September1st to 10thNight
7%32333446%11%53%
1800
11th to 20thNight
7%424435%6%7%10%49%
1926
21st to endNight
8%312435%6%7%9%53%
1980
October1st to 10thNight
43134345%6%8%61%
1980
11th to 20thNight
8%32332435%6%62%
2055
21st to endNight
4413222335%71%
2376
November1st to 10thNight
6%32213335%71%
2288
11th to 20thNight
3413313447%67%
2470
21st to endNight
5%42332345%6%63%
2470
December1st to 10thNight
7%31342335%8%60%
2470
11th to 20thNight
332443445%7%61%
3036
21st to endNight
3312223346%70%
4496

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%35%14%30%24%
1898
11th to 20thDay
21%35%15%34%22%
1840
21st to endDay
23%35%11%35%23%
1980
February1st to 10thDay
20%45%14%25%32%
1800
11th to 20thDay
23%36%14%27%27%
1759
21st to endDay
17%45%12%28%34%
1480
March1st to 10thDay
26%45%16%25%23%
1800
11th to 20thDay
26%46%12%22%30%
1876
21st to endDay
17%46%11%31%32%
2376
April1st to 10thDay
18%46%14%27%32%
2160
11th to 20thDay
17%5%7%11%26%34%
2134
21st to endDay
18%2412%32%31%
2160
May1st to 10thDay
18%36%12%26%35%
2160
11th to 20thDay
22%5%8%19%25%21%
2128
21st to endDay
17%6%10%20%23%23%
2531
June1st to 10thDay
15%7%12%23%26%17%
2340
11th to 20thDay
18%6%8%18%29%20%
2340
21st to endDay
24%8%12%21%21%14%
2340
July1st to 10thDay
36%11%15%23%12%2
2153
11th to 20thDay
27%10%12%25%22%5%
2097
21st to endDay
28%10%17%31%13%1
2219
August1st to 10thDay
25%10%14%32%18%2
2136
11th to 20thDay
41%11%15%21%10%3
2123
21st to endDay
36%10%15%19%15%5%
2376
September1st to 10thDay
37%9%13%18%14%9%
2160
11th to 20thDay
36%9%12%18%19%6%
2032
21st to endDay
29%6%11%19%23%11%
1980
October1st to 10thDay
19%8%11%23%21%18%
1980
11th to 20thDay
23%47%18%24%24%
1900
21st to endDay
17%2416%32%29%
1980
November1st to 10thDay
17%36%19%30%25%
1769
11th to 20thDay
18%49%20%27%22%
1710
21st to endDay
24%45%17%29%22%
1710
December1st to 10thDay
23%37%20%29%18%
1710
11th to 20thDay
21%46%18%30%21%
2159
21st to endDay
16%3414%32%32%
3199
January1st to 10thNight
24%35%13%30%26%
2268
11th to 20thNight
23%45%15%31%23%
2208
21st to endNight
23%36%13%33%22%
2376
February1st to 10thNight
21%36%14%23%32%
2160
11th to 20thNight
26%5%7%12%22%29%
2098
21st to endNight
20%45%9%27%36%
1776
March1st to 10thNight
23%46%15%27%25%
2160
11th to 20thNight
26%46%13%23%28%
2080
21st to endNight
18%47%12%27%32%
1980
April1st to 10thNight
23%5%6%12%26%29%
1800
11th to 20thNight
20%5%8%14%22%32%
1777
21st to endNight
16%48%15%26%32%
1800
May1st to 10thNight
19%5%7%13%24%32%
1800
11th to 20thNight
25%6%10%19%21%20%
1767
21st to endNight
21%7%14%22%18%17%
1746
June1st to 10thNight
18%8%13%29%22%10%
1620
11th to 20thNight
20%8%10%22%26%14%
1620
21st to endNight
21%7%14%22%23%13%
1620
July1st to 10thNight
25%10%19%31%11%3
1690
11th to 20thNight
18%7%14%31%26%4
1740
21st to endNight
18%9%20%37%15%1
1859
August1st to 10thNight
15%7%18%35%24%2
1779
11th to 20thNight
24%12%21%29%11%2
1778
21st to endNight
27%11%18%23%17%5%
1980
September1st to 10thNight
26%7%19%24%15%8%
1800
11th to 20thNight
29%9%18%20%17%7%
1926
21st to endNight
25%9%14%21%21%11%
1980
October1st to 10thNight
19%9%14%22%18%18%
1980
11th to 20thNight
24%47%20%21%24%
2055
21st to endNight
17%35%14%30%31%
2376
November1st to 10thNight
18%45%16%33%25%
2288
11th to 20thNight
19%36%20%28%24%
2470
21st to endNight
22%47%14%29%24%
2470
December1st to 10thNight
23%46%20%26%21%
2470
11th to 20thNight
24%35%17%26%24%
3037
21st to endNight
17%3415%35%25%
4496

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%16%36%28%8%
270
11th to 20thDay
11%13%36%29%10%2
252
21st to endDay
6%25%30%28%9%3
264
February1st to 10thDay
5%19%34%26%14%2
240
11th to 20thDay
13%19%37%20%10%1
240
21st to endDay
6%25%41%19%9%
198
March1st to 10thDay
9%14%43%25%8%1
240
11th to 20thDay
11%19%41%19%8%2
316
21st to endDay
7%23%42%22%5%
462
April1st to 10thDay
7%17%46%24%6%
420
11th to 20thDay
425%44%22%5%
412
21st to endDay
7%16%48%25%5%
420
May1st to 10thDay
415%41%30%9%1
423
11th to 20thDay
49%37%37%11%2
448
21st to endDay
5%6%31%44%14%1
679
June1st to 10thDay
1321%46%25%4
630
11th to 20thDay
3214%48%30%2
630
21st to endDay
4111%38%41%5%
630
July1st to 10thDay
5%18%29%43%13%
498
11th to 20thDay
36%35%41%15%
444
21st to endDay
36%41%38%12%
487
August1st to 10thDay
4425%51%15%
447
11th to 20thDay
7%110%29%38%16%
437
21st to endDay
6%17%28%42%16%
495
September1st to 10thDay
10%17%35%39%9%
450
11th to 20thDay
9%18%32%39%11%
322
21st to endDay
9%211%31%34%12%
270
October1st to 10thDay
7%418%34%29%7%
270
11th to 20thDay
10%421%39%17%7%
270
21st to endDay
8%11%27%27%20%7%
297
November1st to 10thDay
11%7%26%34%17%6%
270
11th to 20thDay
7%12%29%28%17%6%
270
21st to endDay
12%20%28%24%13%2
270
December1st to 10thDay
11%9%31%33%15%1
270
11th to 20thDay
417%40%29%10%
270
21st to endDay
419%37%30%10%
297
January1st to 10thNight
8%7%27%43%13%2
760
11th to 20thNight
8%6%29%40%16%1
736
21st to endNight
6%9%33%39%13%
792
February1st to 10thNight
6%10%28%39%16%2
720
11th to 20thNight
8%7%34%39%11%
704
21st to endNight
6%11%42%35%7%
592
March1st to 10thNight
7%8%34%38%12%1
720
11th to 20thNight
8%10%35%32%14%2
720
21st to endNight
49%40%38%8%1
594
April1st to 10thNight
6%8%38%40%9%
540
11th to 20thNight
5%9%45%34%7%
533
21st to endNight
310%39%40%8%
540
May1st to 10thNight
39%35%42%11%
540
11th to 20thNight
7%5%30%46%12%
531
21st to endNight
46%33%43%14%
584
June1st to 10thNight
3226%52%16%1
540
11th to 20thNight
3127%51%18%
540
21st to endNight
4116%58%20%1
540
July1st to 10thNight
312%50%34%1
525
11th to 20thNight
3111%54%31%1
522
21st to endNight
29%51%36%2
591
August1st to 10thNight
217%45%42%3
537
11th to 20thNight
316%34%50%6%
534
21st to endNight
46%44%42%3
594
September1st to 10thNight
7%16%41%39%5%
540
11th to 20thNight
9%17%44%37%3
540
21st to endNight
8%211%42%35%3
540
October1st to 10thNight
5%216%46%29%2
540
11th to 20thNight
9%217%47%22%3
615
21st to endNight
6%5%19%39%25%7%
792
November1st to 10thNight
8%220%41%25%5%
808
11th to 20thNight
45%20%46%22%3
950
21st to endNight
7%8%25%38%19%3
950
December1st to 10thNight
7%5%24%45%17%2
950
11th to 20thNight
49%33%41%13%1
950
21st to endNight
5%10%32%40%11%2
1022
Page generated at 2024-01-11 21:33:52. Version ac07

Copyright 2024 Attilla Danko


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