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 2018-02-14.

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%
16635
30%
48560
29%
16590
77%
16590
43%
26587

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%
776
30%
2489
31%
776
77%
776
41%
1299
January16th to endNight
70%
832
33%
2496
33%
832
73%
832
42%
1347
February1st to 15thNight
76%
753
33%
2271
35%
753
78%
753
44%
1194
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
83%
717
29%
1790
19%
713
83%
713
49%
1027
August16th to endNight
87%
764
36%
1910
25%
764
87%
764
58%
1019
September1st to 15thNight
86%
720
33%
1845
28%
720
86%
720
52%
1010
September16th to endNight
86%
716
40%
1980
40%
716
86%
716
56%
980
October1st to 15thNight
83%
720
35%
1980
35%
720
84%
720
53%
1013
October16th to endNight
79%
768
39%
2322
42%
768
80%
768
48%
1164
November1st to 15thNight
81%
760
32%
2470
37%
760
83%
760
48%
1175
November16th to endNight
77%
780
36%
2535
40%
780
79%
780
44%
1268
December1st to 15thNight
72%
780
32%
2535
33%
780
76%
780
38%
1337
December16th to endNight
65%
832
33%
2704
32%
832
71%
832
38%
1419

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%
49491
Night
5%423323347%59%
48767
TransparencyDay
22%37%19%25%22%
49189
Night
28%26%16%22%23%
48570
SeeingDay
5%315%35%31%9%
6491
Night
7%2427%41%16%
16649

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%57%
1775
16th to endDay
9%314323345%58%
2080
February1st to 15thDay
7%21331345%6%60%
1883
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
1212112236%75%
2160
16th to endDay
12213336%74%
2292
September1st to 15thDay
112212336%73%
2115
16th to endDay
112212326%74%
1980
October1st to 15thDay
5%313213238%63%
1980
16th to endDay
4312213336%66%
1900
November1st to 15thDay
3212322445%65%
1719
16th to endDay
5%31222345%7%61%
1755
December1st to 15thDay
5%32232435%8%57%
1755
16th to endDay
9%412323346%56%
1872
January1st to 15thNight
7%313324347%57%
2489
16th to endNight
9%413313335%59%
2496
February1st to 15thNight
7%322423436%61%
2269
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%60%
1800
16th to endNight
1314213337%67%
1910
September1st to 15thNight
2312314336%67%
1845
16th to endNight
221221322473%
1980
October1st to 15thNight
3313222345%68%
1980
16th to endNight
5%422222336%64%
2322
November1st to 15thNight
3313322336%65%
2470
16th to endNight
5%323313347%60%
2535
December1st to 15thNight
7%313324446%57%
2535
16th to endNight
10%413212335%59%
2704

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%48%16%20%23%
1776
16th to endDay
28%27%16%16%28%
2080
February1st to 15thDay
25%35%16%24%24%
1883
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%2416%35%26%
2146
16th to endDay
13%2418%34%26%
2292
September1st to 15thDay
14%25%15%33%28%
2115
16th to endDay
16%2315%33%29%
1980
October1st to 15thDay
21%25%19%25%24%
1980
16th to endDay
19%35%15%19%34%
1900
November1st to 15thDay
21%37%18%19%30%
1719
16th to endDay
21%37%15%22%29%
1755
December1st to 15thDay
24%411%16%19%24%
1755
16th to endDay
28%38%16%22%19%
1872
January1st to 15thNight
27%28%14%19%27%
2489
16th to endNight
28%28%14%14%31%
2496
February1st to 15thNight
25%36%15%22%26%
2280
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
26%2316%32%18%
1790
16th to endNight
19%25%12%30%29%
1910
September1st to 15thNight
22%339%31%28%
1845
16th to endNight
19%1211%32%31%
1980
October1st to 15thNight
20%25%18%30%22%
1980
16th to endNight
23%2313%22%35%
2322
November1st to 15thNight
22%26%17%18%33%
2470
16th to endNight
23%35%17%18%30%
2535
December1st to 15thNight
28%37%14%19%26%
2535
16th to endNight
28%28%13%23%22%
2704

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
20%312%32%25%4
164
16th to endDay
9%323%32%25%6%
352
February1st to 15thDay
7%317%32%27%10%
320
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
25%36%41%12%
315
16th to endDay
1329%50%15%
332
September1st to 15thDay
27%47%32%8%
315
16th to endDay
214%44%28%8%
315
October1st to 15thDay
4120%40%26%5%
315
16th to endDay
7%112%37%27%13%
299
November1st to 15thDay
2210%29%37%16%
135
16th to endDay
49%10%31%28%15%
135
December1st to 15thDay
248%34%40%8%
135
16th to endDay
9%413%29%31%11%
144
January1st to 15thNight
8%26%37%31%12%
780
16th to endNight
9%17%34%35%11%
832
February1st to 15thNight
7%1433%37%14%
760
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
31110%55%27%
717
16th to endNight
317%51%36%
764
September1st to 15thNight
4113%54%25%
720
16th to endNight
423%51%19%
716
October1st to 15thNight
31332%45%13%
720
16th to endNight
6%1225%43%20%
768
November1st to 15thNight
4333%41%16%
760
16th to endNight
6%15%30%37%18%
780
December1st to 15thNight
9%25%35%36%10%
780
16th to endNight
11%49%32%31%10%
832
Page generated at 2018-02-15 07:58:43. Version ac04

Copyright 2018 A. Danko


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