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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 2018-03-11.

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
74%
16423
34%
49095
30%
16387
78%
16387
52%
23798

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%
776
27%
2592
26%
776
68%
776
35%
1402
January16th to endNight
60%
832
30%
2704
29%
832
66%
832
36%
1479
February1st to 15thNight
65%
760
33%
2317
33%
760
70%
760
43%
1218
February16th to endNight
56%
684
29%
2051
29%
684
61%
684
35%
1194
March1st to 15thNight
62%
764
23%
2225
22%
764
67%
764
38%
1265
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%
720
42%
1800
33%
720
92%
720
76%
841
September16th to endNight
91%
716
47%
1944
44%
716
93%
716
81%
811
October1st to 15thNight
80%
720
34%
2114
36%
720
82%
720
59%
975
October16th to endNight
78%
768
43%
2304
43%
768
83%
768
57%
1056
November1st to 15thNight
73%
760
34%
2416
34%
760
79%
760
51%
1144
November16th to endNight
72%
780
34%
2535
34%
780
76%
780
47%
1213
December1st to 15thNight
68%
780
30%
2599
30%
780
73%
780
39%
1335
December16th to endNight
56%
832
29%
2912
29%
832
64%
832
32%
1565

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%
49528
Night
4212212335%67%
49283
TransparencyDay
18%38%18%28%21%
49214
Night
18%38%17%27%24%
49097
SeeingDay
8%8%25%36%16%3
6609
Night
6%311%32%35%10%
16434

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%25%313446%54%
1672
16th to endDay
12%5%24323245%54%
1872
February1st to 15thDay
10%5%23422346%55%
1872
16th to endDay
13%5%23313345%51%
1709
March1st to 15thDay
9%314434448%51%
1968
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%
2160
16th to endDay
111122483%
2016
October1st to 15thDay
421322223469%
1843
16th to endDay
221222243471%
1920
November1st to 15thDay
5%312313235%65%
1773
16th to endDay
5%214313448%59%
1755
December1st to 15thDay
8%413313446%56%
1688
16th to endDay
12%42331335%6%52%
1664
January1st to 15thNight
8%424423346%54%
2592
16th to endNight
8%424423345%55%
2704
February1st to 15thNight
7%42332245%7%55%
2307
16th to endNight
11%5%2442433453%
2051
March1st to 15thNight
7%4233345%6%6%50%
2225
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
1111212483%
1800
16th to endNight
1122385%
1944
October1st to 15thNight
321221232472%
2114
16th to endNight
221121213474%
2304
November1st to 15thNight
3312224346%66%
2416
16th to endNight
4312323447%61%
2535
December1st to 15thNight
7%32431445%7%56%
2599
16th to endNight
10%5%24323347%53%
2912

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
29%38%19%23%15%
1672
16th to endDay
32%39%14%20%19%
1872
February1st to 15thDay
29%37%17%26%16%
1872
16th to endDay
33%38%21%25%7%
1709
March1st to 15thDay
29%413%20%19%12%
1968
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%37%
2160
16th to endDay
7%1319%38%29%
2016
October1st to 15thDay
18%36%17%28%25%
1843
16th to endDay
15%36%14%28%31%
1920
November1st to 15thDay
21%36%18%30%20%
1773
16th to endDay
22%39%16%28%20%
1755
December1st to 15thDay
27%49%17%20%20%
1688
16th to endDay
32%46%21%19%15%
1664
January1st to 15thNight
29%47%17%21%18%
2592
16th to endNight
30%48%13%20%23%
2704
February1st to 15thNight
25%37%18%26%18%
2318
16th to endNight
32%36%19%26%10%
2051
March1st to 15thNight
29%5%11%20%20%12%
2225
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%11%29%42%
1800
16th to endNight
5%2412%42%32%
1944
October1st to 15thNight
15%26%16%28%29%
2114
16th to endNight
15%3414%29%31%
2304
November1st to 15thNight
19%37%17%31%21%
2416
16th to endNight
21%310%17%24%22%
2535
December1st to 15thNight
26%49%15%21%22%
2599
16th to endNight
30%49%18%21%15%
2912

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
18%11%30%26%12%
210
16th to endDay
15%11%32%29%9%1
304
February1st to 15thDay
12%10%26%26%18%5%
319
16th to endDay
18%14%30%23%10%2
290
March1st to 15thDay
16%17%27%28%10%
312
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
4120%53%15%4
315
16th to endDay
15%25%45%19%2
315
October1st to 15thDay
310%33%38%12%1
315
16th to endDay
5%10%25%35%16%5%
336
November1st to 15thDay
6%6%20%33%26%5%
189
16th to endDay
8%8%18%37%22%5%
135
December1st to 15thDay
8%6%22%36%23%2
119
16th to endDay
14%11%26%28%16%3
96
January1st to 15thNight
11%315%33%24%13%
780
16th to endNight
11%317%36%22%8%
832
February1st to 15thNight
9%315%33%28%9%
764
16th to endNight
14%6%16%33%22%5%
684
March1st to 15thNight
10%5%16%37%25%5%
764
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
324%54%16%
720
16th to endNight
15%30%47%15%
716
October1st to 15thNight
418%37%38%9%
720
16th to endNight
4110%33%35%13%
768
November1st to 15thNight
5%213%38%29%10%
760
16th to endNight
5%312%37%28%13%
780
December1st to 15thNight
8%312%39%28%7%
780
16th to endNight
12%6%15%37%20%6%
832
Page generated at 2018-03-12 10:28:07. Version ac04

Copyright 2018 A. Danko


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