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Figueroa Lookout
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Figueroa Lookout clear sky chart from 2005-11-05 to 2017-09-10.

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
74%
15695
33%
46828
30%
15659
77%
15659
52%
22676

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
62%
716
27%
2392
26%
716
68%
716
37%
1260
January16th to endNight
58%
768
30%
2496
29%
768
64%
768
36%
1380
February1st to 15thNight
63%
700
32%
2135
31%
700
68%
700
41%
1147
February16th to endNight
55%
632
27%
1895
27%
632
60%
632
33%
1130
March1st to 15thNight
64%
720
24%
2094
23%
720
68%
720
40%
1158
March16th to endNight
65%
768
27%
2026
20%
768
70%
768
46%
1124
April1st to 15thNight
60%
719
29%
1799
17%
719
64%
719
45%
1037
April16th to endNight
64%
720
31%
1800
15%
720
70%
720
58%
937
May1st to 15thNight
75%
710
28%
1790
17%
710
77%
710
63%
887
May16th to endNight
74%
487
33%
1611
27%
487
79%
487
59%
672
June1st to 15thNight
87%
360
35%
1440
40%
360
90%
360
63%
491
June16th to endNight
96%
360
42%
1440
52%
360
98%
360
84%
411
July1st to 15thNight
96%
365
35%
1385
40%
365
96%
365
74%
450
July16th to endNight
91%
564
39%
1593
34%
531
91%
531
69%
663
August1st to 15thNight
92%
714
39%
1788
25%
711
92%
711
82%
789
August16th to endNight
96%
764
46%
1910
31%
764
96%
764
85%
839
September1st to 15thNight
92%
700
42%
1750
33%
700
93%
700
76%
814
September16th to endNight
90%
656
45%
1782
42%
656
92%
656
81%
744
October1st to 15thNight
78%
660
35%
1938
37%
660
81%
660
56%
913
October16th to endNight
77%
704
41%
2112
42%
704
82%
704
57%
974
November1st to 15thNight
73%
700
36%
2225
36%
700
80%
700
54%
1013
November16th to endNight
71%
720
33%
2340
33%
720
76%
720
47%
1121
December1st to 15thNight
66%
720
30%
2399
29%
720
71%
720
37%
1264
December16th to endNight
55%
768
28%
2688
28%
768
62%
768
31%
1458

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
5%212212335%68%
47796
Night
4212212335%67%
47016
TransparencyDay
18%38%18%28%21%
47482
Night
18%38%17%27%24%
46830
SeeingDay
8%8%26%37%15%3
5999
Night
6%311%32%35%10%
15706

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 15thDay
9%5%24213346%56%
1543
16th to endDay
13%5%2432324453%
1728
February1st to 15thDay
11%5%23422346%53%
1724
16th to endDay
14%6%33323345%49%
1579
March1st to 15thDay
8%31443445%8%52%
1863
16th to endDay
7%5%24323447%53%
2196
April1st to 15thDay
9%324312346%56%
2149
16th to endDay
6%212323446%64%
2160
May1st to 15thDay
321312248%69%
2160
16th to endDay
212112346%72%
2499
June1st to 15thDay
221111236%74%
2520
16th to endDay
1112287%
2520
July1st to 15thDay
111112235%78%
2490
16th to endDay
2112112235%75%
2468
August1st to 15thDay
111112484%
2162
16th to endDay
11123482%
2292
September1st to 15thDay
1111112382%
2097
16th to endDay
1111122482%
1848
October1st to 15thDay
5%31322334467%
1690
16th to endDay
2212322435%71%
1760
November1st to 15thDay
5%3231323467%
1634
16th to endDay
5%214313347%60%
1620
December1st to 15thDay
9%4144135%45%54%
1558
16th to endDay
13%5%33313245%52%
1536
January1st to 15thNight
8%424323346%56%
2392
16th to endNight
9%424423345%54%
2496
February1st to 15thNight
7%42342245%7%53%
2125
16th to endNight
12%5%24424335%51%
1895
March1st to 15thNight
6%4233345%6%6%53%
2094
16th to endNight
6%31331445%8%56%
2026
April1st to 15thNight
8%313313336%60%
1799
16th to endNight
3212212337%70%
1800
May1st to 15thNight
111212346%72%
1790
16th to endNight
221111235%76%
1610
June1st to 15thNight
1112235%80%
1440
16th to endNight
11291%
1440
July1st to 15thNight
21135%82%
1467
16th to endNight
11121122380%
1701
August1st to 15thNight
11111288%
1797
16th to endNight
111111288%
1910
September1st to 15thNight
111212483%
1750
16th to endNight
1122385%
1782
October1st to 15thNight
421221332470%
1938
16th to endNight
321121213473%
2112
November1st to 15thNight
4312113235%69%
2225
16th to endNight
3323323447%61%
2340
December1st to 15thNight
7%324314447%54%
2399
16th to endNight
11%5%24313347%52%
2688

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
28%37%19%23%17%
1543
16th to endDay
33%38%13%20%20%
1728
February1st to 15thDay
30%37%18%25%14%
1724
16th to endDay
35%38%21%23%6%
1579
March1st to 15thDay
28%413%20%19%12%
1863
16th to endDay
27%5%13%24%21%6%
2196
April1st to 15thDay
27%412%25%23%7%
2149
16th to endDay
19%410%25%29%9%
2160
May1st to 15thDay
15%312%23%30%14%
2160
16th to endDay
13%312%30%30%9%
2502
June1st to 15thDay
12%39%20%34%19%
2520
16th to endDay
5%1410%36%42%
2520
July1st to 15thDay
10%25%13%28%40%
2343
16th to endDay
12%47%16%31%26%
2313
August1st to 15thDay
7%2414%35%35%
2147
16th to endDay
7%1412%40%33%
2292
September1st to 15thDay
9%25%14%29%39%
2097
16th to endDay
7%1318%38%30%
1848
October1st to 15thDay
20%37%18%28%21%
1690
16th to endDay
15%37%14%29%29%
1760
November1st to 15thDay
19%36%17%31%22%
1634
16th to endDay
22%39%15%27%21%
1620
December1st to 15thDay
29%5%9%17%21%16%
1558
16th to endDay
33%46%22%17%14%
1536
January1st to 15thNight
28%47%16%23%20%
2392
16th to endNight
31%48%11%19%24%
2496
February1st to 15thNight
27%38%18%25%16%
2136
16th to endNight
34%47%18%26%9%
1895
March1st to 15thNight
26%5%11%21%21%13%
2094
16th to endNight
22%5%15%20%24%10%
2026
April1st to 15thNight
24%411%26%24%7%
1799
16th to endNight
15%411%24%30%12%
1800
May1st to 15thNight
12%312%23%29%17%
1791
16th to endNight
11%411%25%32%14%
1611
June1st to 15thNight
8%39%21%33%24%
1440
16th to endNight
347%32%50%
1440
July1st to 15thNight
6%15%12%23%50%
1385
16th to endNight
10%1417%26%38%
1593
August1st to 15thNight
6%1310%29%48%
1788
16th to endNight
5%211%37%42%
1910
September1st to 15thNight
8%25%10%28%43%
1750
16th to endNight
5%2412%41%33%
1782
October1st to 15thNight
17%26%18%29%25%
1938
16th to endNight
16%3414%32%29%
2112
November1st to 15thNight
17%27%16%32%22%
2225
16th to endNight
20%310%18%24%22%
2340
December1st to 15thNight
27%410%16%21%19%
2399
16th to endNight
31%49%19%20%14%
2688

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
19%13%32%24%9%
171
16th to endDay
17%11%33%28%7%1
256
February1st to 15thDay
14%12%28%27%14%2
261
16th to endDay
20%15%32%22%7%2
238
March1st to 15thDay
13%18%27%28%11%
270
16th to endDay
12%17%31%29%8%1
288
April1st to 15thDay
15%16%38%20%7%2
269
16th to endDay
10%21%38%22%41
270
May1st to 15thDay
13%8%34%30%10%3
288
16th to endDay
5%10%39%32%9%2
330
June1st to 15thDay
6%7%25%40%16%3
315
16th to endDay
120%45%23%6%
315
July1st to 15thDay
113%51%26%6%
305
16th to endDay
411%45%26%10%
327
August1st to 15thDay
2116%53%19%5%
315
16th to endDay
9%55%27%6%
332
September1st to 15thDay
4118%54%15%5%
294
16th to endDay
5%27%43%19%2
255
October1st to 15thDay
411%36%34%10%1
255
16th to endDay
5%11%28%36%15%2
272
November1st to 15thDay
5%8%16%32%29%7%
140
16th to endDay
8%10%24%40%15%1
90
December1st to 15thDay
11%6%25%41%13%1
79
16th to endDay
21%12%31%25%9%
64
January1st to 15thNight
10%316%33%23%13%
720
16th to endNight
11%418%35%21%8%
768
February1st to 15thNight
10%316%33%26%9%
704
16th to endNight
15%6%16%33%22%6%
632
March1st to 15thNight
8%5%16%37%25%5%
720
16th to endNight
7%5%16%37%27%4
768
April1st to 15thNight
8%7%18%38%22%4
719
16th to endNight
45%21%33%27%7%
720
May1st to 15thNight
3413%37%34%6%
711
16th to endNight
3315%37%35%4
489
June1st to 15thNight
18%36%46%6%
360
16th to endNight
130%59%8%
360
July1st to 15thNight
112%66%19%
365
16th to endNight
29%64%23%
564
August1st to 15thNight
221%59%14%
714
16th to endNight
17%60%21%
764
September1st to 15thNight
323%55%16%
700
16th to endNight
15%30%46%15%
656
October1st to 15thNight
419%35%38%9%
660
16th to endNight
4111%34%34%13%
704
November1st to 15thNight
5%214%36%30%11%
700
16th to endNight
5%312%37%27%13%
720
December1st to 15thNight
9%312%39%26%8%
720
16th to endNight
13%7%16%37%18%5%
768
Page generated at 2017-09-11 16:35:17. Version ac04

Copyright 2017 A. Danko


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