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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 2017-03-26.

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
73%
15156
33%
45293
30%
15120
77%
15120
52%
21976

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%
748
25%
1976
19%
748
70%
748
46%
1102
April1st to 15thNight
59%
659
29%
1649
17%
659
63%
659
44%
957
April16th to endNight
65%
660
30%
1650
14%
660
70%
660
58%
854
May1st to 15thNight
76%
651
30%
1641
17%
651
78%
651
65%
798
May16th to endNight
74%
445
32%
1473
26%
445
78%
445
60%
604
June1st to 15thNight
86%
330
36%
1320
42%
330
90%
330
62%
454
June16th to endNight
96%
330
40%
1320
49%
330
97%
330
83%
380
July1st to 15thNight
96%
333
37%
1263
42%
333
96%
333
74%
410
July16th to endNight
90%
522
37%
1467
32%
489
91%
489
68%
615
August1st to 15thNight
93%
654
41%
1638
27%
651
93%
651
84%
714
August16th to endNight
95%
700
44%
1750
29%
700
95%
700
85%
768
September1st to 15thNight
93%
660
44%
1650
34%
660
93%
660
78%
758
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%67%
45679
Night
4312212335%67%
45481
TransparencyDay
19%38%18%28%21%
45365
Night
19%38%17%27%24%
45295
SeeingDay
8%9%27%37%13%3
5335
Night
6%311%32%35%10%
15167

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%24323448%52%
2132
April1st to 15thDay
9%324313347%56%
1969
16th to endDay
6%212223445%64%
1980
May1st to 15thDay
321212238%70%
1979
16th to endDay
212112346%72%
2285
June1st to 15thDay
222211236%74%
2310
16th to endDay
11112386%
2310
July1st to 15thDay
111112235%78%
2283
16th to endDay
2112112235%74%
2286
August1st to 15thDay
111112484%
1982
16th to endDay
11223482%
2100
September1st to 15thDay
1111112383%
1980
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%31332445%9%55%
1976
April1st to 15thNight
9%313313336%60%
1649
16th to endNight
3212212336%71%
1650
May1st to 15thNight
111212247%73%
1641
16th to endNight
22111235%77%
1472
June1st to 15thNight
1112235%79%
1320
16th to endNight
11291%
1320
July1st to 15thNight
21235%82%
1345
16th to endNight
111121122380%
1575
August1st to 15thNight
111289%
1647
16th to endNight
111111288%
1750
September1st to 15thNight
111211484%
1650
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
28%6%13%23%21%7%
2132
April1st to 15thDay
27%412%25%22%7%
1969
16th to endDay
20%410%26%30%8%
1980
May1st to 15thDay
15%312%23%30%14%
1979
16th to endDay
13%311%31%30%9%
2288
June1st to 15thDay
13%310%19%34%19%
2310
16th to endDay
5%1410%37%39%
2310
July1st to 15thDay
9%25%13%29%39%
2136
16th to endDay
13%47%16%30%26%
2131
August1st to 15thDay
7%2415%35%35%
1967
16th to endDay
7%2412%40%33%
2100
September1st to 15thDay
9%2413%28%40%
1980
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
23%5%16%20%24%10%
1976
April1st to 15thNight
25%5%11%26%22%8%
1649
16th to endNight
15%411%24%31%12%
1650
May1st to 15thNight
11%313%23%28%18%
1642
16th to endNight
11%310%26%34%13%
1473
June1st to 15thNight
8%49%19%32%24%
1320
16th to endNight
348%33%48%
1320
July1st to 15thNight
6%15%13%24%48%
1263
16th to endNight
11%1417%25%38%
1467
August1st to 15thNight
5%310%31%47%
1638
16th to endNight
5%210%36%43%
1750
September1st to 15thNight
8%15%10%28%45%
1650
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%16%31%30%8%1
267
April1st to 15thDay
16%18%39%19%41
209
16th to endDay
10%21%40%22%31
210
May1st to 15thDay
14%8%36%30%7%2
228
16th to endDay
6%12%40%31%6%2
266
June1st to 15thDay
6%7%28%43%12%2
255
16th to endDay
224%46%20%6%
255
July1st to 15thDay
216%57%20%2
245
16th to endDay
5%113%46%23%9%
271
August1st to 15thDay
2119%54%17%4
255
16th to endDay
111%57%23%5%
268
September1st to 15thDay
4118%56%14%4
255
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%28%4
748
April1st to 15thNight
8%8%18%38%21%3
659
16th to endNight
45%21%32%28%8%
660
May1st to 15thNight
3412%38%34%6%
652
16th to endNight
3415%37%34%4
447
June1st to 15thNight
18%36%47%5%
330
16th to endNight
231%58%6%
330
July1st to 15thNight
113%67%17%
333
16th to endNight
210%62%24%
522
August1st to 15thNight
321%58%15%
654
16th to endNight
17%59%21%
700
September1st to 15thNight
222%55%17%
660
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 2017-03-27 08:15:12. Version ac04

Copyright 2017 A. Danko


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