Tacna Observing Station
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tacna Observing Station clear sky chart from 2005-11-06 to 2024-03-08.

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
78%
24643
40%
79454
34%
24574
84%
24574
60%
33775

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
74%
746
42%
3961
35%
736
81%
736
42%
1313
January11th to 20thNight
78%
745
47%
3888
39%
740
84%
740
47%
1225
January21st to endNight
65%
827
28%
4080
35%
814
77%
814
33%
1827
February1st to 10thNight
70%
760
41%
2280
36%
760
80%
760
58%
1033
February11th to 20thNight
67%
740
39%
2219
35%
740
77%
740
53%
1055
February21st to endNight
65%
628
36%
1884
34%
628
73%
628
52%
915
March1st to 10thNight
65%
750
38%
2166
30%
750
77%
750
55%
1032
March11th to 20thNight
72%
720
41%
1980
33%
720
80%
720
63%
920
March21st to endNight
67%
792
40%
2178
27%
792
79%
792
63%
1012
April1st to 10thNight
69%
720
38%
1980
25%
720
78%
720
68%
874
April11th to 20thNight
68%
711
43%
1799
24%
711
78%
711
72%
833
April21st to endNight
71%
581
50%
1661
31%
581
82%
581
79%
646
May1st to 10thNight
73%
540
45%
1620
33%
540
81%
540
77%
619
May11th to 20thNight
78%
531
45%
1594
35%
531
82%
531
77%
617
May21st to endNight
77%
583
44%
1746
32%
582
84%
582
83%
643
June1st to 10thNight
87%
540
39%
1620
32%
540
89%
540
80%
617
June11th to 20thNight
86%
540
42%
1620
35%
540
88%
540
88%
585
June21st to endNight
89%
540
37%
1620
31%
540
90%
540
75%
648
July1st to 10thNight
90%
525
35%
1575
28%
525
91%
525
71%
652
July11th to 20thNight
87%
522
35%
1566
29%
522
88%
522
61%
706
July21st to endNight
87%
591
35%
1674
28%
558
88%
558
52%
809
August1st to 10thNight
91%
537
39%
1602
32%
534
92%
534
67%
680
August11th to 20thNight
88%
691
35%
1759
26%
691
88%
691
66%
872
August21st to endNight
88%
792
40%
1988
30%
792
89%
792
67%
982
September1st to 10thNight
85%
720
37%
1980
32%
720
87%
720
64%
933
September11th to 20thNight
91%
720
46%
1980
42%
720
92%
720
78%
832
September21st to endNight
85%
720
44%
1980
37%
720
89%
720
76%
840
October1st to 10thNight
79%
720
44%
1980
36%
720
85%
720
70%
877
October11th to 20thNight
85%
720
48%
2063
42%
720
90%
720
78%
834
October21st to endNight
83%
792
47%
2376
41%
792
89%
792
76%
921
November1st to 10thNight
82%
740
44%
2319
41%
740
89%
740
70%
923
November11th to 20thNight
83%
760
41%
2470
42%
760
88%
760
64%
1005
November21st to endNight
73%
760
41%
2470
40%
760
81%
760
56%
1078
December1st to 10thNight
74%
760
40%
2470
40%
760
80%
760
52%
1131
December11th to 20thNight
75%
758
36%
2934
37%
758
82%
758
41%
1408
December21st to endNight
68%
821
25%
4372
36%
817
76%
817
32%
1878

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
2212223346%74%
79055
Night
2212323346%74%
80582
TransparencyDay
13%35%12%24%43%
78782
Night
13%3412%24%44%
80377
SeeingDay
3414%31%33%15%
14368
Night
3213%41%37%4
24703

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
3313323346%69%
2858
11th to 20thDay
3313224345%69%
2860
21st to endDay
7%425%43445%7%56%
3278
February1st to 10thDay
3212312346%72%
1900
11th to 20thDay
3212323346%69%
1850
21st to endDay
2213322445%72%
1570
March1st to 10thDay
311332335%7%69%
1953
11th to 20thDay
3212323347%70%
1980
21st to endDay
2212223335%78%
2178
April1st to 10thDay
1111222437%76%
1980
11th to 20thDay
21111224483%
2104
21st to endDay
1111123486%
2299
May1st to 10thDay
111112235%83%
2340
11th to 20thDay
111111222485%
2301
21st to endDay
111111291%
2530
June1st to 10thDay
21111123386%
2340
11th to 20thDay
1111111291%
2340
21st to endDay
111121223383%
2340
July1st to 10thDay
2112223345%75%
2340
11th to 20thDay
21123245%6%8%66%
2340
21st to endDay
42245%36%6%6%9%51%
2545
August1st to 10thDay
221332346%7%68%
2328
11th to 20thDay
31123235%6%7%67%
2139
21st to endDay
3113223447%70%
2366
September1st to 10thDay
4213324445%69%
1980
11th to 20thDay
211111223382%
1980
21st to endDay
111221233480%
1980
October1st to 10thDay
1112212245%80%
1980
11th to 20thDay
11121112387%
1895
21st to endDay
11111233483%
1980
November1st to 10thDay
111223235%80%
1756
11th to 20thDay
1212322335%76%
1710
21st to endDay
4213213346%71%
1710
December1st to 10thDay
332332345%7%63%
1710
11th to 20thDay
23234345%7%7%59%
2169
21st to endDay
5%325%3236%5%9%56%
3146
January1st to 10thNight
3212323345%71%
4097
11th to 20thNight
2212213335%75%
4110
21st to endNight
7%424433347%59%
4388
February1st to 10thNight
3213323336%71%
2280
11th to 20thNight
3323413346%68%
2218
21st to endNight
2413323436%68%
1884
March1st to 10thNight
331232336%7%67%
2166
11th to 20thNight
3212213345%73%
1980
21st to endNight
2112223347%72%
2178
April1st to 10thNight
1212212345%77%
1980
11th to 20thNight
22221222481%
1799
21st to endNight
1111122486%
1661
May1st to 10thNight
1111223484%
1620
11th to 20thNight
111121222485%
1594
21st to endNight
11111112389%
1746
June1st to 10thNight
111111223485%
1620
11th to 20thNight
11212390%
1620
21st to endNight
111121222484%
1620
July1st to 10thNight
112212345%78%
1620
11th to 20thNight
221232345%8%69%
1620
21st to endNight
22132345%6%11%60%
1773
August1st to 10thNight
112322347%75%
1611
11th to 20thNight
211232345%8%70%
1759
21st to endNight
221132335%7%72%
1988
September1st to 10thNight
3112223335%74%
1980
11th to 20thNight
111111222385%
1980
21st to endNight
11221233482%
1980
October1st to 10thNight
211221233479%
1980
11th to 20thNight
111111223484%
2063
21st to endNight
111111235%83%
2376
November1st to 10thNight
1211212236%79%
2319
11th to 20thNight
1212222346%75%
2470
21st to endNight
3212322337%71%
2470
December1st to 10thNight
3313322446%67%
2470
11th to 20thNight
24245%24447%60%
3041
21st to endNight
5%4245%3445%5%59%
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
17%35%12%34%29%
2859
11th to 20thDay
17%35%21%34%20%
2860
21st to endDay
23%7%8%15%28%19%
3278
February1st to 10thDay
14%25%12%27%40%
1900
11th to 20thDay
17%2416%28%33%
1860
21st to endDay
15%35%15%27%35%
1570
March1st to 10thDay
14%25%11%30%38%
1953
11th to 20thDay
16%3410%23%44%
1980
21st to endDay
12%139%29%45%
2178
April1st to 10thDay
10%2310%29%45%
1980
11th to 20thDay
7%227%24%59%
2107
21st to endDay
6%127%24%59%
2299
May1st to 10thDay
7%127%22%60%
2340
11th to 20thDay
7%236%18%64%
2304
21st to endDay
415%21%68%
2530
June1st to 10thDay
6%12418%69%
2340
11th to 20thDay
5%11211%81%
2340
21st to endDay
9%23411%71%
2340
July1st to 10thDay
13%35%8%16%55%
2276
11th to 20thDay
14%5%9%21%27%23%
2271
21st to endDay
25%7%10%21%20%17%
2404
August1st to 10thDay
14%47%16%24%35%
2313
11th to 20thDay
14%6%9%16%29%28%
2139
21st to endDay
14%46%17%30%29%
2366
September1st to 10thDay
17%45%13%25%36%
1980
11th to 20thDay
8%237%23%56%
1980
21st to endDay
9%347%19%57%
1980
October1st to 10thDay
8%25%11%24%49%
1980
11th to 20thDay
6%128%22%61%
1895
21st to endDay
8%239%22%56%
1980
November1st to 10thDay
9%1312%27%48%
1756
11th to 20thDay
12%2211%24%48%
1710
21st to endDay
15%3412%26%41%
1710
December1st to 10thDay
19%4416%24%32%
1710
11th to 20thDay
20%5%7%19%29%20%
2168
21st to endDay
21%6%11%22%22%18%
3146
January1st to 10thNight
15%3411%29%38%
4097
11th to 20thNight
13%2420%36%24%
4110
21st to endNight
22%6%7%14%29%23%
4388
February1st to 10thNight
16%2412%23%43%
2280
11th to 20thNight
19%2413%24%38%
2219
21st to endNight
18%45%11%23%39%
1884
March1st to 10thNight
17%3211%27%40%
2166
11th to 20thNight
13%3310%22%48%
1980
21st to endNight
14%2410%28%43%
2178
April1st to 10thNight
11%239%29%47%
1980
11th to 20thNight
10%127%24%56%
1799
21st to endNight
5%228%22%61%
1661
May1st to 10thNight
6%137%23%59%
1620
11th to 20thNight
6%126%20%65%
1595
21st to endNight
5%15%23%65%
1746
June1st to 10thNight
6%12318%71%
1620
11th to 20thNight
411310%82%
1620
21st to endNight
9%1247%76%
1620
July1st to 10thNight
10%248%18%57%
1575
11th to 20thNight
13%46%18%30%28%
1566
21st to endNight
15%8%9%23%26%19%
1674
August1st to 10thNight
11%36%17%23%40%
1602
11th to 20thNight
12%5%8%18%29%28%
1759
21st to endNight
13%36%15%28%35%
1988
September1st to 10thNight
14%35%15%25%38%
1980
11th to 20thNight
7%228%23%58%
1980
21st to endNight
8%249%19%58%
1980
October1st to 10thNight
11%2412%22%50%
1980
11th to 20thNight
7%138%18%62%
2063
21st to endNight
7%137%18%64%
2376
November1st to 10thNight
10%139%26%51%
2319
11th to 20thNight
12%238%23%51%
2470
21st to endNight
17%2310%24%44%
2470
December1st to 10thNight
19%3414%23%38%
2470
11th to 20thNight
22%5%6%13%26%28%
3041
21st to endNight
22%6%8%20%25%20%
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
46%16%37%31%6%
270
11th to 20thDay
9%411%34%33%9%
270
21st to endDay
47%16%35%30%9%
377
February1st to 10thDay
5%7%21%28%29%9%
460
11th to 20thDay
5%9%22%32%25%7%
455
21st to endDay
5%9%25%38%17%5%
382
March1st to 10thDay
47%26%36%22%5%
449
11th to 20thDay
48%20%30%25%13%
420
21st to endDay
313%29%28%20%6%
462
April1st to 10thDay
26%23%30%27%13%
420
11th to 20thDay
28%25%31%26%8%
412
21st to endDay
18%21%30%24%15%
420
May1st to 10thDay
26%21%30%27%14%
423
11th to 20thDay
15%21%33%27%13%
448
21st to endDay
16%17%32%32%12%
485
June1st to 10thDay
2211%39%31%14%
450
11th to 20thDay
2114%30%34%18%
450
21st to endDay
127%37%36%17%
450
July1st to 10thDay
25%33%39%22%
446
11th to 20thDay
1325%45%26%
444
21st to endDay
22324%43%26%
487
August1st to 10thDay
31328%40%25%
447
11th to 20thDay
2420%42%31%
437
21st to endDay
2224%41%32%
495
September1st to 10thDay
4210%26%36%21%
450
11th to 20thDay
217%26%43%22%
450
21st to endDay
1213%28%33%24%
450
October1st to 10thDay
2312%26%43%14%
450
11th to 20thDay
2213%28%38%18%
365
21st to endDay
2213%24%38%21%
297
November1st to 10thDay
149%35%35%15%
270
11th to 20thDay
339%32%42%11%
270
21st to endDay
4416%36%28%12%
270
December1st to 10thDay
5%111%36%39%7%
270
11th to 20thDay
3313%40%36%6%
270
21st to endDay
9%5%16%38%26%6%
297
January1st to 10thNight
4215%46%30%3
760
11th to 20thNight
4211%50%30%4
760
21st to endNight
7%219%45%24%2
836
February1st to 10thNight
3317%43%29%5%
760
11th to 20thNight
4318%49%23%2
744
21st to endNight
4322%47%21%2
628
March1st to 10thNight
3423%47%21%2
750
11th to 20thNight
4317%36%33%6%
720
21st to endNight
35%21%41%27%3
792
April1st to 10thNight
15%20%47%24%3
720
11th to 20thNight
2421%44%26%2
711
21st to endNight
16%20%43%29%2
581
May1st to 10thNight
1322%43%30%1
540
11th to 20thNight
1316%46%33%2
531
21st to endNight
1317%47%29%2
584
June1st to 10thNight
119%50%37%2
540
11th to 20thNight
12%47%39%1
540
21st to endNight
217%41%47%3
540
July1st to 10thNight
16%36%53%4
525
11th to 20thNight
35%31%57%5%
522
21st to endNight
2430%58%5%
591
August1st to 10thNight
2336%54%6%
537
11th to 20thNight
1327%61%8%
691
21st to endNight
31326%56%11%
792
September1st to 10thNight
316%29%53%8%
720
11th to 20thNight
2433%55%6%
720
21st to endNight
1110%37%45%6%
720
October1st to 10thNight
2113%39%40%4
720
11th to 20thNight
1110%42%43%4
720
21st to endNight
1211%37%40%8%
792
November1st to 10thNight
1212%43%37%5%
740
11th to 20thNight
228%41%40%7%
760
21st to endNight
5%115%43%32%3
760
December1st to 10thNight
3213%46%34%3
760
11th to 20thNight
4313%51%27%2
760
21st to endNight
5%315%48%25%3
836
Page generated at 2024-03-05 05:24:02. Version ac07

Copyright © 2024 Attilla Danko.


Tacna Observing Station Clear Sky Chart |Charts Home