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

2017-09-12
.

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
54%
16021
21%
46816
15%
15979
60%
15979
28%
29670

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
38%
719
21%
2327
11%
716
50%
716
22%
1453
January16th to endNight
35%
768
23%
2496
14%
768
48%
768
26%
1524
February1st to 15thNight
38%
704
21%
2287
13%
701
51%
701
26%
1372
February16th to endNight
37%
631
26%
1788
14%
631
49%
631
28%
1145
March1st to 15thNight
45%
720
25%
1980
16%
720
54%
720
34%
1227
March16th to endNight
50%
768
22%
2112
14%
768
56%
768
32%
1318
April1st to 15thNight
53%
718
24%
1862
14%
718
58%
718
37%
1155
April16th to endNight
57%
720
23%
1800
14%
720
60%
720
37%
1129
May1st to 15thNight
59%
616
20%
1697
13%
616
61%
616
33%
1056
May16th to endNight
69%
561
18%
1684
15%
561
70%
561
32%
1020
June1st to 15thNight
69%
540
14%
1620
12%
540
69%
540
27%
1046
June16th to endNight
71%
540
13%
1620
12%
540
72%
540
28%
1030
July1st to 15thNight
72%
510
12%
1530
11%
510
73%
510
26%
992
July16th to endNight
73%
564
12%
1595
10%
531
75%
531
26%
1057
August1st to 15thNight
72%
542
14%
1612
12%
539
71%
539
23%
1105
August16th to endNight
67%
764
14%
1910
11%
764
67%
764
23%
1412
September1st to 15thNight
67%
707
18%
1812
15%
707
67%
707
26%
1295
September16th to endNight
54%
657
13%
1829
12%
657
55%
657
20%
1363
October1st to 15thNight
58%
660
27%
1980
27%
660
63%
660
30%
1233
October16th to endNight
56%
704
32%
2112
27%
704
66%
704
36%
1186
November1st to 15thNight
54%
700
30%
2101
23%
700
64%
700
38%
1184
November16th to endNight
49%
720
26%
2226
18%
720
59%
720
31%
1314
December1st to 15thNight
43%
720
22%
2340
15%
720
52%
720
24%
1471
December16th to endNight
42%
768
22%
2496
16%
768
51%
768
23%
1583

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%25%4345%6%8%43%
47842
Night
11%5%245%3445%8%44%
47013
TransparencyDay
36%7%15%20%15%4
47543
Night
37%7%13%19%16%6%
46816
SeeingDay
12%215%24%31%13%
5838
Night
13%418%29%26%6%
16025

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
14%6%25%423445%45%
1611
16th to endDay
14%5%34424436%44%
1728
February1st to 15thDay
15%6%26%323345%45%
1575
16th to endDay
13%5%26%422446%47%
1682
March1st to 15thDay
11%6%2432345%6%48%
1980
16th to endDay
13%415%4245%5%7%46%
2111
April1st to 15thDay
10%41332345%6%53%
2086
16th to endDay
6%3235%34448%52%
2160
May1st to 15thDay
8%42443446%8%47%
2264
16th to endDay
8%4243346%7%9%45%
2431
June1st to 15thDay
8%324436%6%9%12%37%
2340
16th to endDay
5%315%5%45%6%9%10%39%
2340
July1st to 15thDay
6%325%5%37%7%9%12%34%
2340
16th to endDay
7%5%25%5%37%6%9%12%34%
2465
August1st to 15thDay
10%425%6%45%8%10%12%29%
2325
16th to endDay
12%6%36%5%36%8%8%10%29%
2292
September1st to 15thDay
12%4134346%8%11%39%
2065
16th to endDay
15%8%26%7%45%5%6%6%31%
1801
October1st to 15thDay
16%324323246%50%
1650
16th to endDay
9%424323345%56%
1760
November1st to 15thDay
12%314313345%54%
1757
16th to endDay
11%434424345%51%
1731
December1st to 15thDay
13%6%35%5%245%5%7%40%
1620
16th to endDay
14%6%35%323448%42%
1728
January1st to 15thNight
10%7%25%5%35%5%45%44%
2327
16th to endNight
13%5%25%5%24346%46%
2496
February1st to 15thNight
15%5%14323346%47%
2278
16th to endNight
12%6%25%435%446%44%
1788
March1st to 15thNight
11%42442445%6%48%
1980
16th to endNight
12%42432445%6%48%
2112
April1st to 15thNight
9%5%2443435%8%49%
1862
16th to endNight
8%4245%3446%8%48%
1800
May1st to 15thNight
8%5%235%3445%7%48%
1696
16th to endNight
8%4144245%6%10%45%
1682
June1st to 15thNight
8%4245%35%6%7%12%39%
1620
16th to endNight
5%325%5%35%6%8%14%39%
1620
July1st to 15thNight
6%4346%36%7%7%11%37%
1620
16th to endNight
5%5%25%6%37%6%8%11%36%
1703
August1st to 15thNight
8%4246%46%8%9%13%31%
1623
16th to endNight
10%6%246%36%7%9%11%29%
1910
September1st to 15thNight
10%5%26%7%347%6%9%36%
1812
16th to endNight
18%7%36%6%35%5%5%8%29%
1829
October1st to 15thNight
15%5%23323335%48%
1980
16th to endNight
8%424433245%56%
2112
November1st to 15thNight
9%414423335%57%
2101
16th to endNight
11%42442335%6%49%
2226
December1st to 15thNight
15%6%245%2445%6%42%
2340
16th to endNight
14%5%35%5%2446%7%40%
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
40%5%11%16%21%6%
1612
16th to endDay
41%48%17%21%6%
1728
February1st to 15thDay
40%37%20%21%5%
1577
16th to endDay
38%48%23%19%6%
1682
March1st to 15thDay
36%411%19%20%7%
1980
16th to endDay
37%6%12%20%17%4
2112
April1st to 15thDay
29%5%13%24%21%5%
2086
16th to endDay
29%6%13%21%20%7%
2160
May1st to 15thDay
32%8%15%26%15%1
2264
16th to endDay
32%8%21%24%12%
2435
June1st to 15thDay
34%11%21%22%9%
2340
16th to endDay
34%12%21%23%7%
2340
July1st to 15thDay
35%13%21%22%5%1
2201
16th to endDay
35%12%24%20%5%
2310
August1st to 15thDay
40%12%21%20%4
2312
16th to endDay
43%13%22%15%5%
2292
September1st to 15thDay
35%11%18%17%13%3
2065
16th to endDay
50%7%11%15%12%2
1801
October1st to 15thDay
35%410%21%22%4
1650
16th to endDay
29%38%20%27%10%
1760
November1st to 15thDay
32%39%18%25%10%
1757
16th to endDay
35%39%18%22%9%
1731
December1st to 15thDay
42%6%11%18%13%7%
1620
16th to endDay
40%5%13%18%16%6%
1728
January1st to 15thNight
41%49%15%20%7%
2327
16th to endNight
40%37%18%21%8%
2496
February1st to 15thNight
38%38%18%20%10%
2287
16th to endNight
39%49%20%18%8%
1788
March1st to 15thNight
34%5%12%20%19%8%
1980
16th to endNight
34%6%12%22%17%6%
2112
April1st to 15thNight
33%412%21%20%7%
1862
16th to endNight
31%7%13%20%20%7%
1800
May1st to 15thNight
33%7%14%22%19%2
1697
16th to endNight
31%9%18%28%11%1
1684
June1st to 15thNight
36%10%21%23%8%
1620
16th to endNight
33%12%22%23%7%
1620
July1st to 15thNight
35%12%25%17%8%
1530
16th to endNight
36%12%22%22%5%
1595
August1st to 15thNight
38%14%19%20%6%
1612
16th to endNight
42%14%19%19%4
1910
September1st to 15thNight
42%10%15%15%13%2
1812
16th to endNight
50%9%11%15%10%2
1829
October1st to 15thNight
36%6%8%19%21%6%
1980
16th to endNight
30%38%18%26%12%
2112
November1st to 15thNight
30%38%18%24%13%
2101
16th to endNight
34%411%17%21%11%
2226
December1st to 15thNight
40%5%12%17%16%7%
2340
16th to endNight
41%5%11%17%15%7%
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
18%333%27%15%1
90
16th to endDay
16%132%41%8%
96
February1st to 15thDay
13%5%34%35%11%
90
16th to endDay
12%7%34%35%9%
207
March1st to 15thDay
13%5%26%33%20%
270
16th to endDay
12%325%33%22%3
288
April1st to 15thDay
12%5%24%27%22%7%
270
16th to endDay
7%316%25%35%10%
270
May1st to 15thDay
7%123%36%23%6%
288
16th to endDay
10%11%19%34%23%
331
June1st to 15thDay
8%15%24%39%20%
315
16th to endDay
7%1418%43%24%
315
July1st to 15thDay
6%1414%46%24%
305
16th to endDay
7%215%50%23%
326
August1st to 15thDay
15%1217%41%21%
313
16th to endDay
15%5%12%35%29%
332
September1st to 15thDay
13%15%22%37%19%
299
16th to endDay
21%19%25%29%11%
254
October1st to 15thDay
22%117%22%25%9%
255
16th to endDay
11%218%27%27%13%
272
November1st to 15thDay
14%6%20%24%26%7%
265
16th to endDay
11%6%21%29%24%5%
201
December1st to 15thDay
23%123%30%17%4
90
16th to endDay
19%416%37%19%2
96
January1st to 15thNight
14%11%29%29%14%1
720
16th to endNight
16%8%34%32%7%
768
February1st to 15thNight
18%8%30%35%7%
704
16th to endNight
15%6%33%34%9%
631
March1st to 15thNight
14%428%36%15%
720
16th to endNight
14%325%33%20%2
768
April1st to 15thNight
11%6%22%32%22%4
718
16th to endNight
9%421%32%27%4
720
May1st to 15thNight
9%319%35%27%4
617
16th to endNight
10%10%26%34%16%
563
June1st to 15thNight
10%17%28%40%12%
540
16th to endNight
7%16%25%42%17%
540
July1st to 15thNight
7%15%22%48%13%
510
16th to endNight
6%1424%53%9%
564
August1st to 15thNight
10%1221%50%13%
542
16th to endNight
12%1418%42%20%
764
September1st to 15thNight
12%15%23%46%11%
707
16th to endNight
23%18%26%30%9%
657
October1st to 15thNight
18%213%29%28%7%
660
16th to endNight
10%5%20%29%27%6%
704
November1st to 15thNight
12%323%33%22%5%
700
16th to endNight
12%7%23%32%19%3
720
December1st to 15thNight
18%6%24%31%17%2
720
16th to endNight
17%6%26%33%14%1
768
Page generated at 2017-09-13 07:39:05. Version ac04

Copyright 2017 A. Danko


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