Laguna Niguel
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Laguna Niguel clear sky chart from 2005-11-05 to 2017-08-12.

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
76%
15887
30%
46337
28%
15842
77%
15842
42%
25458

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
74%
716
30%
2297
31%
716
78%
716
42%
1185
January16th to endNight
69%
768
32%
2304
32%
768
71%
768
40%
1268
February1st to 15thNight
75%
697
33%
2103
35%
697
77%
697
44%
1109
February16th to endNight
63%
632
26%
1895
29%
632
66%
632
31%
1166
March1st to 15thNight
72%
720
29%
2160
33%
720
75%
720
43%
1161
March16th to endNight
74%
768
26%
2016
23%
768
76%
768
42%
1191
April1st to 15thNight
67%
719
26%
1799
18%
719
69%
719
41%
1104
April16th to endNight
75%
720
28%
1800
18%
720
75%
720
47%
1048
May1st to 15thNight
70%
611
23%
1691
17%
611
70%
611
35%
1056
May16th to endNight
72%
561
21%
1685
17%
561
73%
561
33%
1039
June1st to 15thNight
71%
540
18%
1620
16%
540
71%
540
28%
1078
June16th to endNight
82%
394
27%
1474
29%
394
82%
394
33%
768
July1st to 15thNight
78%
387
23%
1407
25%
387
78%
387
34%
742
July16th to endNight
82%
665
25%
1686
19%
624
82%
624
43%
982
August1st to 15thNight
84%
701
29%
1750
19%
697
84%
697
50%
996
August16th to endNight
88%
700
35%
1750
24%
700
88%
700
60%
917
September1st to 15thNight
86%
660
35%
1691
29%
660
86%
660
52%
930
September16th to endNight
86%
656
39%
1815
39%
656
86%
656
57%
894
October1st to 15thNight
82%
660
35%
1815
35%
660
82%
660
52%
942
October16th to endNight
79%
704
37%
2128
40%
704
80%
704
48%
1068
November1st to 15thNight
82%
700
34%
2275
39%
700
83%
700
50%
1059
November16th to endNight
76%
720
34%
2340
38%
720
79%
720
44%
1166
December1st to 15thNight
71%
720
32%
2340
33%
720
74%
720
36%
1260
December16th to endNight
63%
768
32%
2496
30%
768
69%
768
37%
1329

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
4313313347%63%
47611
Night
5%423323346%59%
46544
TransparencyDay
22%37%19%25%22%
47309
Night
28%26%16%22%23%
46347
SeeingDay
5%315%36%30%7%
5823
Night
7%2427%41%15%
15901

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%423213446%58%
1638
16th to endDay
9%314323345%57%
1920
February1st to 15thDay
7%313313446%59%
1751
16th to endDay
11%424323447%51%
1579
March1st to 15thDay
431322446%8%58%
1800
16th to endDay
421232445%9%58%
2205
April1st to 15thDay
5%422324448%58%
2149
16th to endDay
4212213347%66%
2160
May1st to 15thDay
4423323348%60%
2259
16th to endDay
441331335%8%60%
2429
June1st to 15thDay
6%6%23313237%59%
2340
16th to endDay
1112212225%75%
2478
July1st to 15thDay
1313323347%64%
2463
16th to endDay
1212223347%67%
2363
August1st to 15thDay
1112112236%75%
2114
16th to endDay
12112336%75%
2100
September1st to 15thDay
112212335%74%
1939
16th to endDay
112212326%74%
1815
October1st to 15thDay
5%413213248%61%
1815
16th to endDay
5%312213336%66%
1742
November1st to 15thDay
3212322345%68%
1584
16th to endDay
5%21222345%7%62%
1620
December1st to 15thDay
6%42342435%9%55%
1620
16th to endDay
10%412323346%56%
1728
January1st to 15thNight
7%313324346%59%
2297
16th to endNight
9%413313335%58%
2304
February1st to 15thNight
7%322423326%61%
2101
16th to endNight
13%414434345%49%
1895
March1st to 15thNight
6%5%2331335%9%56%
2160
16th to endNight
5%42342435%8%54%
2016
April1st to 15thNight
8%6%23413247%54%
1799
16th to endNight
6%424312247%61%
1800
May1st to 15thNight
5%9%25%423347%51%
1691
16th to endNight
5%8%26%433447%50%
1684
June1st to 15thNight
5%7%46%5%34448%44%
1620
16th to endNight
15%15%5%25%447%55%
1474
July1st to 15thNight
2426%5%2447%8%50%
1491
16th to endNight
342443445%8%54%
1802
August1st to 15thNight
2313425%347%61%
1760
16th to endNight
313213237%69%
1750
September1st to 15thNight
2312314336%67%
1691
16th to endNight
221221332473%
1815
October1st to 15thNight
3313322245%67%
1815
16th to endNight
5%422212336%64%
2128
November1st to 15thNight
3312312336%67%
2275
16th to endNight
5%323313347%61%
2340
December1st to 15thNight
8%324324446%56%
2340
16th to endNight
11%42331232459%
2496

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
25%47%15%21%25%
1639
16th to endDay
30%27%16%15%28%
1920
February1st to 15thDay
26%35%16%23%23%
1751
16th to endDay
31%47%21%26%8%
1579
March1st to 15thDay
22%410%21%21%19%
1800
16th to endDay
24%413%24%20%12%
2205
April1st to 15thDay
24%49%28%22%10%
2149
16th to endDay
19%313%23%23%17%
2160
May1st to 15thDay
25%48%24%21%15%
2259
16th to endDay
24%39%30%25%7%
2432
June1st to 15thDay
28%47%17%29%13%
2340
16th to endDay
17%1411%26%38%
2478
July1st to 15thDay
21%35%14%25%29%
2318
16th to endDay
19%39%22%27%16%
2216
August1st to 15thDay
14%2417%35%26%
2100
16th to endDay
12%25%19%34%26%
2100
September1st to 15thDay
14%25%13%33%30%
1939
16th to endDay
16%2315%32%30%
1815
October1st to 15thDay
23%36%20%24%23%
1815
16th to endDay
20%36%15%20%33%
1742
November1st to 15thDay
19%36%18%19%32%
1584
16th to endDay
20%38%16%22%29%
1620
December1st to 15thDay
25%412%16%19%21%
1620
16th to endDay
29%49%16%21%18%
1728
January1st to 15thNight
26%27%13%19%29%
2297
16th to endNight
30%28%13%14%31%
2304
February1st to 15thNight
25%36%15%21%26%
2112
16th to endNight
39%25%14%22%15%
1895
March1st to 15thNight
27%27%20%20%20%
2160
16th to endNight
29%410%20%20%14%
2016
April1st to 15thNight
32%27%23%20%12%
1799
16th to endNight
27%29%21%21%17%
1800
May1st to 15thNight
36%39%18%17%15%
1692
16th to endNight
38%28%20%19%10%
1685
June1st to 15thNight
44%36%11%23%10%
1620
16th to endNight
31%2310%24%27%
1474
July1st to 15thNight
31%25%13%22%23%
1407
16th to endNight
29%38%20%24%13%
1686
August1st to 15thNight
25%2317%32%18%
1750
16th to endNight
18%26%13%29%30%
1750
September1st to 15thNight
23%348%31%30%
1691
16th to endNight
19%1212%32%32%
1815
October1st to 15thNight
22%25%17%30%21%
1815
16th to endNight
23%2313%23%33%
2128
November1st to 15thNight
21%25%16%19%36%
2275
16th to endNight
23%36%18%17%31%
2340
December1st to 15thNight
29%48%14%20%23%
2340
16th to endNight
29%29%14%22%21%
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
23%416%38%16%1
117
16th to endDay
11%325%34%23%2
288
February1st to 15thDay
9%418%34%28%5%
266
16th to endDay
12%5%29%31%18%2
238
March1st to 15thDay
6%5%24%33%22%6%
270
16th to endDay
5%8%20%37%23%4
288
April1st to 15thDay
6%6%28%40%13%5%
269
16th to endDay
25%30%40%15%4
270
May1st to 15thDay
5%421%40%23%5%
288
16th to endDay
6%317%42%23%5%
330
June1st to 15thDay
7%117%35%30%7%
315
16th to endDay
15%34%45%13%
315
July1st to 15thDay
215%28%48%14%
305
16th to endDay
3126%51%16%
327
August1st to 15thDay
35%36%43%12%
300
16th to endDay
230%51%13%
268
September1st to 15thDay
27%50%31%7%
255
16th to endDay
214%45%28%7%
255
October1st to 15thDay
5%221%42%24%3
255
16th to endDay
7%111%42%28%7%
238
November1st to 15thDay
48%24%37%24%
90
16th to endDay
310%13%34%30%8%
90
December1st to 15thDay
36%6%37%37%7%
90
16th to endDay
12%5%13%37%28%3
96
January1st to 15thNight
8%26%39%29%13%
720
16th to endNight
10%17%34%34%11%
768
February1st to 15thNight
7%2434%37%12%
704
16th to endNight
13%110%36%29%8%
632
March1st to 15thNight
7%27%38%33%10%
720
16th to endNight
7%26%30%42%10%
768
April1st to 15thNight
9%48%34%34%7%
719
16th to endNight
7%35%35%38%9%
720
May1st to 15thNight
10%35%30%38%10%
612
16th to endNight
7%5%5%31%40%9%
563
June1st to 15thNight
9%4329%45%7%
540
16th to endNight
4317%61%12%
394
July1st to 15thNight
5%17%58%26%
387
16th to endNight
4117%49%34%
665
August1st to 15thNight
3110%55%28%
701
16th to endNight
317%51%37%
700
September1st to 15thNight
4111%55%26%
660
16th to endNight
3122%51%20%
656
October1st to 15thNight
41333%43%14%
660
16th to endNight
7%2225%43%19%
704
November1st to 15thNight
41331%41%18%
700
16th to endNight
6%15%30%38%17%
720
December1st to 15thNight
10%25%34%35%10%
720
16th to endNight
12%49%32%30%9%
768
Page generated at 2017-08-13 11:16:29. Version ac04

Copyright 2017 A. Danko


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