Huntington Beach State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Huntington Beach State Park clear sky chart from 2005-11-05 to 2019-06-02.

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
54%
18386
21%
53776
15%
18344
60%
18344
28%
34096

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
37%
839
22%
2717
12%
836
51%
836
22%
1692
January16th to endNight
36%
896
24%
2912
15%
896
49%
896
27%
1763
February1st to 15thNight
39%
824
21%
2677
14%
821
50%
821
26%
1620
February16th to endNight
39%
735
24%
2083
14%
735
50%
735
27%
1359
March1st to 15thNight
45%
840
26%
2310
16%
840
54%
840
33%
1441
March16th to endNight
48%
896
22%
2464
14%
896
55%
896
31%
1553
April1st to 15thNight
53%
838
23%
2173
14%
838
58%
838
35%
1373
April16th to endNight
57%
831
24%
2077
14%
831
60%
831
38%
1294
May1st to 15thNight
62%
719
21%
1980
14%
719
64%
719
34%
1219
May16th to endNight
69%
657
18%
1972
15%
657
70%
657
31%
1210
June1st to 15thNight
70%
588
14%
1765
12%
588
71%
588
27%
1140
June16th to endNight
71%
585
13%
1755
11%
585
72%
585
28%
1117
July1st to 15thNight
74%
555
13%
1665
12%
555
74%
555
27%
1071
July16th to endNight
71%
612
11%
1739
10%
579
73%
579
25%
1171
August1st to 15thNight
73%
578
14%
1718
13%
575
72%
575
23%
1178
August16th to endNight
68%
828
13%
2070
10%
828
68%
828
25%
1508
September1st to 15thNight
68%
780
18%
2002
15%
780
69%
780
26%
1417
September16th to endNight
59%
777
14%
2161
14%
777
59%
777
22%
1556
October1st to 15thNight
61%
780
27%
2340
27%
780
65%
780
31%
1441
October16th to endNight
56%
832
32%
2496
27%
832
66%
832
36%
1407
November1st to 15thNight
54%
820
28%
2461
22%
820
62%
820
35%
1440
November16th to endNight
50%
840
26%
2597
19%
840
59%
840
32%
1516
December1st to 15thNight
41%
840
22%
2730
14%
840
51%
840
23%
1749
December16th to endNight
41%
896
21%
2912
15%
896
49%
896
22%
1861

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
10%5%244345%6%8%43%
54557
Night
11%5%245%345%5%8%44%
53973
TransparencyDay
36%8%15%20%15%4
54258
Night
36%7%13%19%16%5%
53776
SeeingDay
12%215%25%30%13%
8153
Night
13%418%29%26%6%
18390

By Month

Percentage Cloud Cover SE (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
13%6%25%5%13446%45%
1881
16th to endDay
13%5%345%24436%45%
2016
February1st to 15thDay
14%6%26%333445%44%
1845
16th to endDay
14%5%25%433446%45%
1959
March1st to 15thDay
11%6%2442345%6%48%
2310
16th to endDay
12%425%4245%5%7%45%
2463
April1st to 15thDay
10%5%1332345%6%51%
2434
16th to endDay
6%323434448%54%
2488
May1st to 15thDay
7%42443446%8%48%
2642
16th to endDay
8%4243246%7%9%44%
2847
June1st to 15thDay
8%324436%6%9%12%37%
2548
16th to endDay
5%315%5%45%6%9%10%40%
2535
July1st to 15thDay
6%325%5%36%7%9%12%35%
2535
16th to endDay
7%5%25%5%47%6%9%12%33%
2673
August1st to 15thDay
9%425%6%46%8%10%12%29%
2471
16th to endDay
11%6%35%5%36%8%8%9%30%
2484
September1st to 15thDay
12%4134346%7%11%39%
2285
16th to endDay
13%7%26%6%35%5%6%7%35%
2129
October1st to 15thDay
14%324323346%51%
1950
16th to endDay
8%424323345%57%
2080
November1st to 15thDay
13%414323345%51%
2057
16th to endDay
10%435%423345%52%
2019
December1st to 15thDay
15%6%35%5%245%5%7%39%
1890
16th to endDay
14%6%35%324447%42%
2016
January1st to 15thNight
10%6%25%5%35%5%45%44%
2717
16th to endNight
13%5%25%5%24346%46%
2912
February1st to 15thNight
15%5%24323446%45%
2668
16th to endNight
13%6%25%43445%7%42%
2083
March1st to 15thNight
11%41442445%6%48%
2310
16th to endNight
11%425%42445%6%47%
2464
April1st to 15thNight
9%5%2443435%8%47%
2173
16th to endNight
8%4245%2445%8%50%
2077
May1st to 15thNight
8%5%234345%5%8%48%
1979
16th to endNight
9%5%144245%6%10%45%
1970
June1st to 15thNight
8%424435%6%7%12%40%
1765
16th to endNight
5%325%5%35%5%8%14%38%
1755
July1st to 15thNight
5%4346%46%7%7%11%38%
1755
16th to endNight
6%5%26%6%37%6%8%11%35%
1847
August1st to 15thNight
8%4246%46%8%9%13%30%
1729
16th to endNight
9%6%246%36%7%9%11%31%
2070
September1st to 15thNight
10%5%26%6%347%6%10%37%
2002
16th to endNight
16%7%26%5%35%6%6%8%33%
2161
October1st to 15thNight
13%5%24333346%48%
2340
16th to endNight
8%424433345%56%
2496
November1st to 15thNight
11%414423335%54%
2461
16th to endNight
11%42442335%6%50%
2597
December1st to 15thNight
16%6%245%2445%6%41%
2730
16th to endNight
15%5%25%5%2445%6%40%
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
39%5%10%17%21%5%
1882
16th to endDay
39%38%18%21%7%
2016
February1st to 15thDay
41%48%20%20%4
1847
16th to endDay
40%48%21%18%6%
1959
March1st to 15thDay
36%411%19%19%8%
2310
16th to endDay
37%6%12%20%18%4
2464
April1st to 15thDay
31%5%13%24%19%5%
2434
16th to endDay
28%6%12%23%20%7%
2488
May1st to 15thDay
30%8%14%26%16%2
2642
16th to endDay
32%9%19%24%13%
2851
June1st to 15thDay
34%11%21%21%10%
2548
16th to endDay
34%12%22%23%6%
2535
July1st to 15thDay
34%13%21%22%6%1
2396
16th to endDay
37%12%24%19%5%
2518
August1st to 15thDay
40%13%22%19%4
2458
16th to endDay
42%13%23%15%5%
2484
September1st to 15thDay
35%11%19%16%13%3
2285
16th to endDay
46%8%12%17%12%2
2129
October1st to 15thDay
34%5%11%22%22%4
1950
16th to endDay
29%48%20%27%10%
2080
November1st to 15thDay
34%49%18%23%9%
2057
16th to endDay
34%310%19%23%9%
2019
December1st to 15thDay
43%6%11%18%14%6%
1890
16th to endDay
40%5%12%19%16%5%
2016
January1st to 15thNight
40%5%9%16%20%7%
2717
16th to endNight
39%37%18%22%8%
2912
February1st to 15thNight
38%39%18%19%9%
2677
16th to endNight
41%49%19%17%7%
2083
March1st to 15thNight
35%5%11%19%19%8%
2310
16th to endNight
35%6%12%21%17%5%
2464
April1st to 15thNight
34%5%12%21%18%7%
2173
16th to endNight
31%6%12%22%19%8%
2077
May1st to 15thNight
31%7%14%23%19%3
1980
16th to endNight
32%9%16%28%11%1
1972
June1st to 15thNight
34%11%21%22%8%
1765
16th to endNight
33%12%22%24%6%
1755
July1st to 15thNight
33%12%25%18%8%
1665
16th to endNight
38%12%22%22%4
1739
August1st to 15thNight
37%15%20%20%6%
1718
16th to endNight
40%14%20%19%4
2070
September1st to 15thNight
40%11%17%15%12%2
2002
16th to endNight
45%9%13%18%10%2
2161
October1st to 15thNight
35%7%10%21%19%6%
2340
16th to endNight
30%48%18%26%12%
2496
November1st to 15thNight
33%39%17%23%11%
2461
16th to endNight
33%411%18%21%10%
2597
December1st to 15thNight
42%5%11%16%16%6%
2730
16th to endNight
42%5%11%19%15%6%
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
15%5%28%38%11%
180
16th to endDay
14%227%42%11%1
192
February1st to 15thDay
14%231%37%13%
180
16th to endDay
16%5%28%34%13%
306
March1st to 15thDay
12%6%28%35%16%
390
16th to endDay
12%323%36%19%3
416
April1st to 15thDay
14%422%29%23%5%
390
16th to endDay
7%317%27%34%9%
379
May1st to 15thDay
6%119%32%27%12%
408
16th to endDay
11%10%18%36%23%
459
June1st to 15thDay
8%1422%40%22%
379
16th to endDay
6%1417%45%25%
375
July1st to 15thDay
5%1413%48%26%
365
16th to endDay
8%1317%48%21%
390
August1st to 15thDay
13%1318%41%21%
358
16th to endDay
13%5%13%37%30%
396
September1st to 15thDay
13%15%19%37%22%
375
16th to endDay
16%18%21%36%15%
374
October1st to 15thDay
17%114%20%27%18%
375
16th to endDay
9%220%27%27%12%
400
November1st to 15thDay
17%5%19%25%23%8%
385
16th to endDay
11%422%32%23%5%
309
December1st to 15thDay
27%120%28%18%2
180
16th to endDay
19%423%36%14%1
192
January1st to 15thNight
14%10%29%29%13%1
840
16th to endNight
15%7%34%33%8%
896
February1st to 15thNight
18%7%29%36%8%
824
16th to endNight
15%6%32%34%11%
735
March1st to 15thNight
14%429%37%13%
840
16th to endNight
13%327%34%19%2
896
April1st to 15thNight
11%5%21%33%23%3
838
16th to endNight
9%421%33%27%4
831
May1st to 15thNight
9%318%33%29%6%
720
16th to endNight
11%9%25%36%16%
659
June1st to 15thNight
9%17%28%40%12%
588
16th to endNight
7%15%24%43%17%
585
July1st to 15thNight
7%15%21%50%14%
555
16th to endNight
7%1425%51%9%
612
August1st to 15thNight
10%1221%50%14%
578
16th to endNight
11%1418%43%20%
828
September1st to 15thNight
12%15%22%45%13%
780
16th to endNight
20%17%24%34%11%
777
October1st to 15thNight
16%213%28%29%9%
780
16th to endNight
10%5%20%29%27%6%
832
November1st to 15thNight
14%322%32%21%5%
820
16th to endNight
12%7%23%32%20%4
840
December1st to 15thNight
19%5%24%31%16%2
840
16th to endNight
18%6%26%34%13%1
896
Page generated at 2019-06-02 19:43:11. Version ac04

Copyright 2019 A. Danko


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