Emerald Beach
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Emerald Beach clear sky chart from 2005-11-06 to 2024-01-13.

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
57%
23504
22%
74484
18%
23449
63%
23449
29%
44764

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 10thNight
35%
760
23%
2407
13%
757
46%
757
24%
1501
January11th to 20thNight
43%
732
28%
2196
16%
732
53%
732
29%
1315
January21st to endNight
32%
792
25%
2376
11%
792
45%
792
23%
1551
February1st to 10thNight
39%
720
24%
2160
13%
720
48%
720
26%
1371
February11th to 20thNight
36%
701
23%
2099
10%
700
47%
700
28%
1310
February21st to endNight
39%
592
22%
1776
13%
592
46%
592
25%
1160
March1st to 10thNight
46%
720
25%
2160
14%
720
54%
720
32%
1286
March11th to 20thNight
49%
720
22%
2059
13%
720
56%
720
31%
1269
March21st to endNight
51%
712
25%
2098
16%
712
59%
712
34%
1229
April1st to 10thNight
50%
540
24%
1800
20%
540
58%
540
28%
1057
April11th to 20thNight
54%
533
24%
1775
21%
533
61%
533
30%
1032
April21st to endNight
68%
540
32%
1800
31%
540
74%
540
44%
880
May1st to 10thNight
68%
540
25%
1774
25%
540
72%
540
41%
920
May11th to 20thNight
71%
531
20%
1592
18%
531
73%
531
35%
927
May21st to endNight
75%
582
23%
1744
22%
582
76%
582
36%
1008
June1st to 10thNight
71%
540
15%
1620
15%
540
71%
540
29%
1003
June11th to 20thNight
82%
540
17%
1620
18%
540
82%
540
35%
942
June21st to endNight
76%
540
13%
1620
13%
540
76%
540
30%
992
July1st to 10thNight
77%
525
11%
1575
11%
525
77%
525
26%
1040
July11th to 20thNight
78%
522
10%
1617
11%
522
78%
522
27%
1047
July21st to endNight
81%
591
12%
1858
14%
558
81%
558
30%
1107
August1st to 10thNight
84%
537
11%
1778
13%
534
84%
534
31%
1045
August11th to 20thNight
75%
534
9%
1776
11%
534
75%
534
23%
1152
August21st to endNight
70%
594
15%
1980
18%
594
70%
594
21%
1310
September1st to 10thNight
72%
584
16%
1844
17%
584
72%
584
28%
1173
September11th to 20thNight
66%
720
17%
1980
13%
720
68%
720
28%
1330
September21st to endNight
70%
720
28%
1980
24%
720
72%
720
36%
1202
October1st to 10thNight
65%
720
28%
1980
23%
720
69%
720
39%
1157
October11th to 20thNight
68%
720
38%
1980
32%
720
73%
720
46%
1070
October21st to endNight
58%
792
29%
2333
25%
792
63%
792
35%
1365
November1st to 10thNight
60%
740
29%
2406
27%
740
67%
740
39%
1249
November11th to 20thNight
50%
760
30%
2470
23%
760
61%
760
33%
1368
November21st to endNight
47%
760
25%
2470
20%
760
55%
760
31%
1433
December1st to 10thNight
45%
760
24%
2470
19%
760
54%
760
27%
1501
December11th to 20thNight
40%
759
22%
2914
15%
758
49%
758
21%
1750
December21st to endNight
36%
831
15%
4397
14%
817
45%
817
13%
2712

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
9%5%25%5%35%5%7%9%45%
74781
Night
9%5%25%5%35%5%6%9%47%
74967
TransparencyDay
34%9%15%19%16%6%
74516
Night
34%8%14%19%18%7%
74751
SeeingDay
10%5%18%26%27%14%
13504
Night
11%5%19%27%28%10%
23514

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 10thDay
12%5%25%5%445%6%8%43%
1753
11th to 20thDay
11%7%245%23447%49%
1826
21st to endDay
16%7%26%5%34446%42%
1980
February1st to 10thDay
15%8%35%5%34447%43%
1800
11th to 20thDay
13%6%35%42445%8%46%
1748
21st to endDay
13%7%45%5%445%6%7%39%
1480
March1st to 10thDay
9%6%25%5%25%46%7%49%
1800
11th to 20thDay
11%5%25%5%36%5%6%7%45%
1899
21st to endDay
10%5%25%5%345%5%7%50%
2272
April1st to 10thDay
11%5%345%3445%8%48%
2160
11th to 20thDay
10%6%25%445%5%5%7%48%
2134
21st to endDay
7%42342445%7%58%
2160
May1st to 10thDay
7%32342445%7%58%
2182
11th to 20thDay
6%425%435%6%7%11%48%
2301
21st to endDay
5%424435%5%7%11%50%
2531
June1st to 10thDay
7%5%35%6%47%6%9%11%37%
2340
11th to 20thDay
5%324447%8%9%14%41%
2340
21st to endDay
6%435%7%46%7%8%13%37%
2340
July1st to 10thDay
8%436%6%47%7%9%13%32%
2340
11th to 20thDay
7%5%26%7%47%8%11%13%29%
2283
21st to endDay
6%425%6%47%9%10%14%34%
2350
August1st to 10thDay
7%4146%36%8%9%14%35%
2148
11th to 20thDay
8%426%6%5%6%8%9%14%33%
2125
21st to endDay
10%5%36%6%36%6%8%9%38%
2376
September1st to 10thDay
7%6%25%5%36%7%9%10%42%
2097
11th to 20thDay
10%6%26%5%36%6%8%9%40%
1980
21st to endDay
6%4245%347%7%9%50%
1980
October1st to 10thDay
6%5%234345%5%8%55%
1980
11th to 20thDay
8%323423347%61%
1980
21st to endDay
8%4245%3445%6%55%
2017
November1st to 10thDay
7%5%2342345%6%59%
1672
11th to 20thDay
9%5%2342335%8%55%
1710
21st to endDay
10%5%25%5%345%6%8%48%
1710
December1st to 10thDay
12%6%25%5%335%5%8%46%
1710
11th to 20thDay
13%7%46%5%3445%6%43%
2153
21st to endDay
15%9%46%5%24445%42%
3124
January1st to 10thNight
14%7%25%5%345%5%6%45%
2407
11th to 20thNight
11%6%25%42346%8%48%
2196
21st to endNight
16%8%35%5%3445%6%42%
2376
February1st to 10thNight
14%7%36%5%24346%47%
2160
11th to 20thNight
15%7%35%42345%6%47%
2098
21st to endNight
15%7%345%345%5%6%43%
1776
March1st to 10thNight
10%5%245%3446%8%49%
2160
11th to 20thNight
10%6%25%5%35%46%8%46%
2059
21st to endNight
9%424435%45%8%51%
2098
April1st to 10thNight
10%6%35%5%35%46%7%47%
1800
11th to 20thNight
11%6%25%43446%7%47%
1775
21st to endNight
6%32343445%8%61%
1800
May1st to 10thNight
6%42432445%9%56%
1774
11th to 20thNight
5%4245%346%7%10%50%
1592
21st to endNight
6%4245%35%5%7%10%51%
1744
June1st to 10thNight
6%5%36%6%45%5%9%11%41%
1620
11th to 20thNight
4224436%6%10%13%47%
1620
21st to endNight
6%424436%7%9%13%41%
1620
July1st to 10thNight
6%426%446%6%10%12%38%
1620
11th to 20thNight
4325%6%36%8%10%14%40%
1671
21st to endNight
42246%46%7%10%13%42%
1968
August1st to 10thNight
4315%5%37%6%9%14%44%
1790
11th to 20thNight
7%5%246%46%7%9%15%36%
1776
21st to endNight
7%5%36%6%46%5%9%10%38%
1980
September1st to 10thNight
7%426%7%46%7%7%13%38%
1844
11th to 20thNight
9%5%35%6%5%5%6%6%9%41%
1980
21st to endNight
7%5%25%4346%5%9%50%
1980
October1st to 10thNight
6%5%25%4335%6%8%54%
1980
11th to 20thNight
6%42432345%6%61%
1980
21st to endNight
9%435%4345%5%6%52%
2333
November1st to 10thNight
8%5%2342345%7%58%
2406
11th to 20thNight
9%5%25%43445%7%54%
2470
21st to endNight
11%425%5%3445%7%49%
2470
December1st to 10thNight
12%5%35%5%25%447%46%
2470
11th to 20thNight
14%6%35%5%345%5%7%43%
3042
21st to endNight
15%10%36%6%34446%41%
4532

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 10thDay
37%7%9%16%22%8%
1754
11th to 20thDay
35%5%10%18%23%8%
1826
21st to endDay
43%5%7%15%21%9%
1980
February1st to 10thDay
42%6%9%15%19%10%
1800
11th to 20thDay
37%6%10%18%20%9%
1758
21st to endDay
41%9%11%15%15%8%
1480
March1st to 10thDay
33%7%9%21%21%8%
1800
11th to 20thDay
35%8%15%16%18%8%
1899
21st to endDay
33%8%13%21%17%8%
2272
April1st to 10thDay
35%7%11%18%20%8%
2160
11th to 20thDay
34%7%10%21%20%8%
2134
21st to endDay
25%7%12%24%23%8%
2160
May1st to 10thDay
24%6%14%27%21%8%
2182
11th to 20thDay
27%11%20%22%18%2
2305
21st to endDay
26%12%17%24%19%3
2531
June1st to 10thDay
37%11%20%25%7%1
2340
11th to 20thDay
27%12%23%28%9%1
2340
21st to endDay
35%13%24%18%9%1
2340
July1st to 10thDay
40%15%26%15%3
2275
11th to 20thDay
39%18%27%13%3
2214
21st to endDay
32%16%30%18%4
2219
August1st to 10thDay
32%16%28%20%3
2136
11th to 20thDay
36%17%27%14%5%
2125
21st to endDay
38%13%22%18%7%2
2376
September1st to 10thDay
33%14%22%17%9%4
2097
11th to 20thDay
38%11%17%17%12%6%
1980
21st to endDay
28%11%14%19%22%7%
1980
October1st to 10thDay
26%8%13%21%20%13%
1980
11th to 20thDay
24%5%10%23%26%12%
1980
21st to endDay
31%5%6%15%27%16%
2017
November1st to 10thDay
28%49%21%25%13%
1672
11th to 20thDay
30%5%9%19%27%11%
1710
21st to endDay
33%6%10%20%21%10%
1710
December1st to 10thDay
36%7%15%17%18%7%
1710
11th to 20thDay
42%6%6%17%19%9%
2150
21st to endDay
44%5%8%18%22%3
3124
January1st to 10thNight
40%6%8%13%25%9%
2407
11th to 20thNight
35%6%9%18%24%9%
2196
21st to endNight
44%47%12%25%8%
2376
February1st to 10thNight
41%48%17%21%10%
2160
11th to 20thNight
38%5%9%15%21%13%
2099
21st to endNight
41%7%9%17%15%12%
1776
March1st to 10thNight
33%7%11%18%22%9%
2160
11th to 20thNight
35%6%13%20%16%9%
2059
21st to endNight
31%7%13%21%19%10%
2098
April1st to 10thNight
35%6%13%16%19%11%
1800
11th to 20thNight
34%6%10%22%20%9%
1775
21st to endNight
22%5%11%28%26%8%
1800
May1st to 10thNight
25%6%13%22%26%9%
1774
11th to 20thNight
28%9%19%22%19%3
1593
21st to endNight
26%10%17%24%20%3
1745
June1st to 10thNight
34%10%23%24%9%1
1620
11th to 20thNight
24%13%25%26%10%1
1620
21st to endNight
30%13%28%19%9%1
1620
July1st to 10thNight
34%15%26%20%5%
1575
11th to 20thNight
27%20%34%15%4
1617
21st to endNight
28%13%33%22%4
1858
August1st to 10thNight
25%15%33%22%4
1778
11th to 20thNight
34%16%31%16%3
1776
21st to endNight
39%13%21%19%6%2
1980
September1st to 10thNight
35%11%25%15%11%3
1844
11th to 20thNight
38%10%16%17%14%5%
1980
21st to endNight
30%8%13%22%20%7%
1980
October1st to 10thNight
28%7%11%20%21%13%
1980
11th to 20thNight
24%49%22%28%12%
1980
21st to endNight
32%5%8%15%25%16%
2333
November1st to 10thNight
27%410%19%24%17%
2406
11th to 20thNight
32%46%19%27%12%
2470
21st to endNight
35%5%10%19%20%12%
2470
December1st to 10thNight
37%6%12%19%20%6%
2470
11th to 20thNight
40%5%9%14%21%11%
3044
21st to endNight
45%6%7%19%20%3
4532

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 10thDay
16%11%39%25%9%1
270
11th to 20thDay
10%11%33%30%15%1
248
21st to endDay
22%13%39%19%6%
264
February1st to 10thDay
18%13%35%27%8%
240
11th to 20thDay
15%10%37%30%9%
240
21st to endDay
9%11%44%31%6%
198
March1st to 10thDay
9%9%43%32%7%
240
11th to 20thDay
14%10%31%31%12%1
339
21st to endDay
12%10%30%34%14%2
462
April1st to 10thDay
14%7%30%32%15%3
420
11th to 20thDay
13%9%27%29%19%2
412
21st to endDay
7%326%36%24%4
420
May1st to 10thDay
6%423%34%27%6%
423
11th to 20thDay
7%111%38%29%13%
447
21st to endDay
7%17%31%36%17%
485
June1st to 10thDay
10%29%29%35%15%
450
11th to 20thDay
7%28%22%37%23%
450
21st to endDay
9%15%21%35%28%
450
July1st to 10thDay
7%25%13%40%33%
445
11th to 20thDay
7%1410%40%38%
444
21st to endDay
6%415%42%32%
488
August1st to 10thDay
8%1213%38%38%
446
11th to 20thDay
9%2210%40%37%
439
21st to endDay
7%37%19%37%27%
495
September1st to 10thDay
8%25%17%40%27%
450
11th to 20thDay
13%37%21%40%18%
450
21st to endDay
8%18%27%38%17%
450
October1st to 10thDay
8%217%37%28%8%
450
11th to 20thDay
7%416%26%36%11%
450
21st to endDay
10%7%18%33%27%5%
392
November1st to 10thDay
11%416%33%31%6%
270
11th to 20thDay
13%6%23%34%21%3
270
21st to endDay
11%6%26%37%16%4
270
December1st to 10thDay
15%9%29%30%14%3
270
11th to 20thDay
18%11%30%32%9%1
270
21st to endDay
21%7%29%30%11%1
297
January1st to 10thNight
15%13%33%29%10%1
760
11th to 20thNight
13%12%27%33%14%1
732
21st to endNight
19%10%34%29%7%
792
February1st to 10thNight
15%11%29%33%11%1
720
11th to 20thNight
16%12%31%27%13%
703
21st to endNight
16%10%30%34%9%
592
March1st to 10thNight
14%6%31%35%14%1
720
11th to 20thNight
12%7%28%32%19%3
720
21st to endNight
10%7%26%35%21%1
712
April1st to 10thNight
13%7%24%35%20%2
540
11th to 20thNight
12%5%24%30%26%3
533
21st to endNight
7%317%35%32%6%
540
May1st to 10thNight
7%315%33%34%9%
540
11th to 20thNight
6%112%32%38%11%
531
21st to endNight
7%18%20%50%14%
584
June1st to 10thNight
8%15%23%47%14%
540
11th to 20thNight
31420%48%23%
540
21st to endNight
8%1415%48%25%
540
July1st to 10thNight
7%1212%46%32%
525
11th to 20thNight
5%118%40%45%
522
21st to endNight
41212%49%33%
591
August1st to 10thNight
4110%42%43%
537
11th to 20thNight
9%28%45%35%
534
21st to endNight
8%26%16%43%24%
594
September1st to 10thNight
8%2418%43%25%
584
11th to 20thNight
10%38%20%45%13%
720
21st to endNight
10%29%26%42%12%
720
October1st to 10thNight
7%217%36%32%6%
720
11th to 20thNight
6%417%31%32%10%
720
21st to endNight
11%5%18%33%29%4
792
November1st to 10thNight
10%5%20%38%23%4
740
11th to 20thNight
12%7%26%33%20%1
760
21st to endNight
12%6%28%32%20%2
760
December1st to 10thNight
13%8%28%29%19%3
760
11th to 20thNight
16%8%31%28%17%1
760
21st to endNight
20%10%28%28%13%1
836
Page generated at 2024-01-10 19:35:21. Version ac07

Copyright 2024 Attilla Danko


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