Observatorio Las Palmas
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatorio Las Palmas clear sky chart from 2005-11-05 to 2017-10-31.

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
0%
2292
0%
12817
0%
1182
0%
1182
55%
22486

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 15thNight
0%
108
0%
480
0%
45
0%
45
60%
981
January16th to endNight
0%
184
0%
731
0%
98
0%
98
45%
1237
February1st to 15thNight
0%
136
0%
487
0%
60
0%
60
57%
977
February16th to endNight
0%
155
0%
482
0%
84
0%
84
52%
911
March1st to 15thNight
0%
172
0%
426
0%
67
0%
67
61%
949
March16th to endNight
0%
145
0%
392
0%
52
0%
52
64%
988
April1st to 15thNight
0%
148
0%
358
0%
61
0%
61
64%
922
April16th to endNight
0%
104
0%
175
0%
22
0%
22
76%
643
May1st to 15thNight
0%
96
0%
167
0%
16
0%
16
78%
631
May16th to endNight
0%
62
0%
94
0%
10
0%
10
88%
609
June1st to 15thNight
0%
42
0%
186
0%
18
0%
18
76%
642
June16th to endNight
0%
35
0%
386
0%
22
0%
22
61%
734
July1st to 15thNight
0%
42
0%
868
0%
36
0%
36
32%
929
July16th to endNight
0%
74
0%
1250
0%
61
0%
61
19%
1155
August1st to 15thNight
0%
38
0%
976
0%
37
0%
37
33%
968
August16th to endNight
0%
60
0%
1131
0%
56
0%
56
34%
1178
September1st to 15thNight
0%
65
0%
942
0%
63
0%
63
41%
1137
September16th to endNight
0%
42
0%
421
0%
32
0%
32
67%
903
October1st to 15thNight
0%
77
0%
424
0%
58
0%
58
64%
937
October16th to endNight
0%
59
0%
308
0%
28
0%
28
74%
927
November1st to 15thNight
0%
65
0%
346
0%
34
0%
34
67%
890
November16th to endNight
0%
124
0%
527
0%
76
0%
76
55%
1028
December1st to 15thNight
0%
113
0%
551
0%
69
0%
69
55%
1041
December16th to endNight
0%
146
0%
709
0%
77
0%
77
50%
1169

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
TransparencyDay
17%36%10%21%40%
48005
Night
17%36%11%22%39%
47440
SeeingDay
4317%34%26%13%
5646
Night
49%38%38%8%
15859

By Month

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 15thDay
13%1311%24%44%
1612
16th to endDay
23%2312%22%36%
1728
February1st to 15thDay
15%136%23%48%
1724
16th to endDay
17%146%28%42%
1674
March1st to 15thDay
18%125%20%51%
1980
16th to endDay
15%125%21%54%
2112
April1st to 15thDay
14%12421%55%
1973
16th to endDay
7%15%17%66%
2160
May1st to 15thDay
6%12318%68%
2253
16th to endDay
41217%73%
2432
June1st to 15thDay
9%2318%65%
2340
16th to endDay
12%348%26%44%
2340
July1st to 15thDay
31%10%16%17%14%9%
2201
16th to endDay
35%13%21%21%7%1
2312
August1st to 15thDay
27%10%16%23%14%6%
2325
16th to endDay
27%9%15%24%14%8%
2211
September1st to 15thDay
27%5%10%22%22%11%
1980
16th to endDay
14%2412%33%31%
1980
October1st to 15thDay
13%25%12%27%38%
1884
16th to endDay
9%139%22%53%
1918
November1st to 15thDay
11%127%27%48%
1759
16th to endDay
18%1310%21%45%
1759
December1st to 15thDay
17%2411%26%37%
1620
16th to endDay
19%26%12%28%31%
1728
January1st to 15thNight
14%2410%25%42%
2327
16th to endNight
24%2210%24%36%
2496
February1st to 15thNight
17%238%23%45%
2136
16th to endNight
21%137%26%39%
1799
March1st to 15thNight
15%237%20%50%
1980
16th to endNight
14%225%21%54%
2112
April1st to 15thNight
14%117%26%48%
1975
16th to endNight
7%16%18%65%
1800
May1st to 15thNight
7%1315%70%
1695
16th to endNight
31221%70%
1685
June1st to 15thNight
8%125%16%66%
1620
16th to endNight
14%36%6%28%41%
1620
July1st to 15thNight
30%10%15%19%14%9%
1530
16th to endNight
41%16%20%17%21
1593
August1st to 15thNight
27%11%20%20%12%5%
1611
16th to endNight
26%12%17%22%13%7%
1987
September1st to 15thNight
25%8%14%24%19%8%
1980
16th to endNight
11%26%17%30%30%
1980
October1st to 15thNight
13%2412%26%40%
2075
16th to endNight
9%1210%25%50%
2304
November1st to 15thNight
12%128%25%48%
2100
16th to endNight
19%1310%23%42%
2199
December1st to 15thNight
17%1313%28%34%
2340
16th to endNight
20%25%11%27%32%
2496

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 15thDay
3214%46%31%2
90
16th to endDay
27%15%36%31%7%
96
February1st to 15thDay
37%19%35%28%6%
239
16th to endDay
9%6%29%32%15%6%
238
March1st to 15thDay
5%6%32%28%17%8%
270
16th to endDay
25%31%34%16%9%
288
April1st to 15thDay
49%32%30%17%4
269
16th to endDay
18%34%32%13%8%
270
May1st to 15thDay
112%34%36%12%2
288
16th to endDay
327%50%15%2
330
June1st to 15thDay
3117%51%20%6%
315
16th to endDay
211%45%30%10%
315
July1st to 15thDay
6%7%35%31%18%
305
16th to endDay
7%430%30%25%
327
August1st to 15thDay
5%422%36%30%
315
16th to endDay
5%319%40%31%
332
September1st to 15thDay
7%426%40%20%
315
16th to endDay
5%6%38%35%13%
315
October1st to 15thDay
210%33%30%21%
219
16th to endDay
7%16%34%40%
144
November1st to 15thDay
5%111%28%38%14%
90
16th to endDay
2118%32%40%5%
90
December1st to 15thDay
14%24%37%23%
90
16th to endDay
9%312%55%17%2
96
January1st to 15thNight
310%47%34%2
720
16th to endNight
8%14%44%26%4
768
February1st to 15thNight
4113%46%30%3
704
16th to endNight
6%17%50%21%3
632
March1st to 15thNight
4117%46%26%2
720
16th to endNight
2115%45%31%3
768
April1st to 15thNight
3115%51%26%1
716
16th to endNight
117%49%30%
540
May1st to 15thNight
15%50%30%1
540
16th to endNight
9%46%40%2
563
June1st to 15thNight
15%40%48%3
540
16th to endNight
1430%56%5%
540
July1st to 15thNight
4327%51%12%
510
16th to endNight
6%1421%45%19%
564
August1st to 15thNight
3316%51%24%
539
16th to endNight
5%315%49%25%
663
September1st to 15thNight
6%216%51%23%
720
16th to endNight
3224%58%11%
716
October1st to 15thNight
45%31%47%9%
720
16th to endNight
15%33%47%10%
768
November1st to 15thNight
26%40%40%10%
700
16th to endNight
5%10%40%35%6%
720
December1st to 15thNight
5%19%43%34%6%
720
16th to endNight
5%12%49%27%4
768
Page generated at 2017-11-01 14:23:29. Version ac04

Copyright 2017 A. Danko


Observatorio Las Palmas Clear Sky Chart |Charts Home