Cachuma Lake Recreation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cachuma Lake Recreation Area clear sky chart from 2005-11-05 to 2017-03-13.

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
62%
15128
34%
45139
26%
15087
71%
15087
45%
21710

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
52%
716
28%
2389
21%
716
64%
716
31%
1219
January16th to endNight
51%
768
32%
2496
25%
768
63%
768
31%
1328
February1st to 15thNight
52%
700
34%
2119
29%
696
61%
696
36%
1121
February16th to endNight
48%
632
28%
1895
22%
632
59%
632
30%
1117
March1st to 15thNight
54%
712
28%
2072
20%
712
65%
712
37%
1096
March16th to endNight
53%
704
29%
1856
19%
704
62%
704
43%
1007
April1st to 15thNight
48%
659
31%
1649
16%
659
55%
659
42%
927
April16th to endNight
53%
660
31%
1650
12%
660
61%
660
51%
831
May1st to 15thNight
59%
654
31%
1644
15%
654
65%
654
53%
802
May16th to endNight
53%
455
32%
1483
17%
455
66%
455
48%
619
June1st to 15thNight
68%
330
33%
1320
30%
330
80%
330
43%
506
June16th to endNight
75%
330
39%
1320
34%
330
90%
330
63%
403
July1st to 15thNight
82%
338
34%
1268
35%
338
86%
338
55%
460
July16th to endNight
73%
525
37%
1470
26%
492
84%
492
53%
650
August1st to 15thNight
82%
657
39%
1640
25%
653
84%
653
67%
767
August16th to endNight
86%
700
42%
1750
23%
700
91%
700
75%
774
September1st to 15thNight
83%
660
43%
1650
32%
660
85%
660
65%
783
September16th to endNight
80%
656
46%
1784
36%
656
88%
656
72%
758
October1st to 15thNight
73%
660
36%
1933
36%
660
78%
660
55%
887
October16th to endNight
69%
704
42%
2112
36%
704
81%
704
53%
962
November1st to 15thNight
63%
700
37%
2223
34%
700
73%
700
50%
980
November16th to endNight
60%
720
36%
2340
30%
720
72%
720
41%
1091
December1st to 15thNight
55%
720
33%
2388
28%
720
65%
720
33%
1221
December16th to endNight
48%
768
31%
2688
25%
768
60%
768
29%
1401

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
4212213346%67%
45529
Night
4212213346%68%
45338
TransparencyDay
18%37%19%29%20%
45217
Night
17%37%17%28%24%
45151
SeeingDay
5%16%20%34%19%2
5289
Night
5%17%11%27%30%9%
15139

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
8%315%32335%5%58%
1546
16th to endDay
13%32331433456%
1728
February1st to 15thDay
9%423313346%56%
1731
16th to endDay
13%423323347%50%
1579
March1st to 15thDay
6%21342445%8%54%
1832
16th to endDay
6%41331435%8%56%
2015
April1st to 15thDay
7%314313347%58%
1969
16th to endDay
421221345%6%66%
1980
May1st to 15thDay
2212213346%69%
1976
16th to endDay
21112347%73%
2276
June1st to 15thDay
222212246%71%
2310
16th to endDay
11213483%
2310
July1st to 15thDay
111223337%71%
2277
16th to endDay
2212322336%69%
2281
August1st to 15thDay
11122136%76%
1980
16th to endDay
21223479%
2100
September1st to 15thDay
21111212480%
1980
16th to endDay
111213382%
1845
October1st to 15thDay
5%12323345%67%
1694
16th to endDay
2212222345%72%
1760
November1st to 15thDay
321222333470%
1635
16th to endDay
4213323247%64%
1620
December1st to 15thDay
7%41332445%5%56%
1569
16th to endDay
11%423322336%55%
1536
January1st to 15thNight
7%324423345%57%
2389
16th to endNight
8%413323436%56%
2496
February1st to 15thNight
7%42331335%7%57%
2119
16th to endNight
11%32442435%452%
1895
March1st to 15thNight
5%3133235%6%7%57%
2072
16th to endNight
5%21322446%8%58%
1856
April1st to 15thNight
7%313323335%62%
1649
16th to endNight
2111212347%71%
1650
May1st to 15thNight
122212346%73%
1644
16th to endNight
211211235%77%
1482
June1st to 15thNight
11213448%71%
1320
16th to endNight
1112486%
1320
July1st to 15thNight
1112336%77%
1350
16th to endNight
111322235%73%
1578
August1st to 15thNight
1111135%81%
1650
16th to endNight
11212385%
1750
September1st to 15thNight
11121222480%
1650
16th to endNight
11123484%
1784
October1st to 15thNight
3112212335%72%
1933
16th to endNight
2212212225%74%
2112
November1st to 15thNight
2312212235%71%
2223
16th to endNight
3213324347%64%
2340
December1st to 15thNight
6%32331345%6%58%
2388
16th to endNight
10%412313347%56%
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
26%46%18%24%18%
1546
16th to endDay
29%48%15%21%21%
1728
February1st to 15thDay
27%36%19%25%17%
1731
16th to endDay
32%38%23%22%8%
1579
March1st to 15thDay
24%6%12%21%23%11%
1832
16th to endDay
24%413%24%22%9%
2015
April1st to 15thDay
24%5%12%25%23%8%
1969
16th to endDay
17%5%9%25%31%10%
1980
May1st to 15thDay
15%311%24%28%15%
1976
16th to endDay
11%5%10%34%29%8%
2279
June1st to 15thDay
16%29%21%34%15%
2310
16th to endDay
7%2411%40%33%
2310
July1st to 15thDay
14%26%12%30%33%
2131
16th to endDay
17%47%19%30%21%
2126
August1st to 15thDay
12%25%14%39%25%
1966
16th to endDay
10%3412%40%29%
2100
September1st to 15thDay
10%25%13%31%35%
1980
16th to endDay
9%2317%39%28%
1845
October1st to 15thDay
18%47%20%27%22%
1694
16th to endDay
15%35%16%30%29%
1760
November1st to 15thDay
17%36%19%29%24%
1635
16th to endDay
19%48%18%26%23%
1620
December1st to 15thDay
25%5%10%16%25%16%
1569
16th to endDay
28%5%7%21%22%13%
1536
January1st to 15thNight
25%46%17%24%20%
2389
16th to endNight
27%5%7%13%21%25%
2496
February1st to 15thNight
24%45%19%26%18%
2130
16th to endNight
31%6%6%18%26%10%
1895
March1st to 15thNight
21%6%10%22%25%13%
2072
16th to endNight
20%5%12%23%25%13%
1856
April1st to 15thNight
24%311%26%25%9%
1649
16th to endNight
12%5%10%24%31%15%
1650
May1st to 15thNight
12%312%22%29%20%
1645
16th to endNight
11%49%25%35%13%
1483
June1st to 15thNight
13%410%18%33%19%
1320
16th to endNight
5%148%34%45%
1320
July1st to 15thNight
10%25%10%26%44%
1268
16th to endNight
15%1416%29%32%
1470
August1st to 15thNight
10%228%33%42%
1640
16th to endNight
6%39%38%41%
1750
September1st to 15thNight
11%248%28%44%
1650
16th to endNight
6%2211%42%33%
1784
October1st to 15thNight
14%35%19%29%27%
1933
16th to endNight
14%4412%31%32%
2112
November1st to 15thNight
15%26%15%32%27%
2223
16th to endNight
19%36%20%24%25%
2340
December1st to 15thNight
24%5%8%16%24%20%
2388
16th to endNight
27%5%7%20%23%15%
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
13%21%29%21%13%1
174
16th to endDay
14%21%24%26%12%1
256
February1st to 15thDay
10%23%19%23%19%2
263
16th to endDay
14%22%26%24%11%1
238
March1st to 15thDay
7%27%22%27%14%
259
16th to endDay
5%26%25%31%8%1
224
April1st to 15thDay
6%31%28%23%8%1
209
16th to endDay
131%33%22%8%1
210
May1st to 15thDay
6%21%29%32%8%1
228
16th to endDay
424%30%29%10%
266
June1st to 15thDay
5%14%24%40%15%
255
16th to endDay
12%17%42%21%5%
255
July1st to 15thDay
5%8%9%48%25%1
245
16th to endDay
411%9%35%32%5%
271
August1st to 15thDay
37%12%48%27%
255
16th to endDay
26%7%38%41%3
268
September1st to 15thDay
5%5%12%49%23%2
255
16th to endDay
10%13%42%28%5%
255
October1st to 15thDay
313%23%38%19%1
255
16th to endDay
5%12%24%30%23%3
272
November1st to 15thDay
310%11%29%34%10%
141
16th to endDay
411%23%40%18%2
90
December1st to 15thDay
7%6%25%41%17%1
81
16th to endDay
6%17%31%34%7%3
64
January1st to 15thNight
8%18%12%25%23%11%
720
16th to endNight
8%19%15%27%19%8%
768
February1st to 15thNight
8%19%15%25%22%8%
704
16th to endNight
11%19%15%27%21%4
632
March1st to 15thNight
5%21%13%32%21%5%
712
16th to endNight
421%17%30%22%3
704
April1st to 15thNight
5%22%19%30%17%3
659
16th to endNight
223%17%27%22%6%
660
May1st to 15thNight
321%12%32%25%4
655
16th to endNight
223%17%27%26%2
457
June1st to 15thNight
119%7%35%33%2
330
16th to endNight
18%428%41%6%
330
July1st to 15thNight
212%116%51%15%
338
16th to endNight
317%110%46%20%
525
August1st to 15thNight
210%223%46%13%
657
16th to endNight
19%117%50%19%
700
September1st to 15thNight
39%121%49%14%
660
16th to endNight
19%8%25%42%13%
656
October1st to 15thNight
311%8%31%36%9%
660
16th to endNight
49%11%28%34%11%
704
November1st to 15thNight
415%12%29%27%11%
700
16th to endNight
419%10%29%24%10%
720
December1st to 15thNight
6%20%11%30%24%6%
720
16th to endNight
10%23%13%30%17%4
768
Page generated at 2017-03-14 01:34:46. Version ac04

Copyright 2017 A. Danko


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