Keaton Beach
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Keaton Beach clear sky chart from 2005-11-05 to 2017-12-04.

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
52%
15974
22%
47887
16%
15936
59%
15936
27%
29295

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
33%
717
21%
2327
11%
716
47%
716
22%
1427
January16th to endNight
35%
768
24%
2379
15%
768
45%
768
23%
1515
February1st to 15thNight
38%
701
25%
2106
16%
700
48%
700
26%
1280
February16th to endNight
38%
631
25%
1893
12%
631
51%
631
25%
1164
March1st to 15thNight
42%
720
28%
2016
15%
720
53%
720
32%
1182
March16th to endNight
47%
768
26%
2112
14%
768
56%
768
32%
1232
April1st to 15thNight
49%
718
23%
1976
15%
718
55%
718
30%
1198
April16th to endNight
54%
570
31%
1764
22%
570
64%
570
37%
904
May1st to 15thNight
59%
539
26%
1619
19%
539
64%
539
35%
872
May16th to endNight
63%
561
24%
1682
15%
561
70%
561
33%
928
June1st to 15thNight
62%
540
16%
1620
12%
540
65%
540
25%
1021
June16th to endNight
60%
540
13%
1620
10%
540
63%
540
24%
1036
July1st to 15thNight
69%
510
12%
1530
11%
510
70%
510
25%
979
July16th to endNight
66%
564
8%
1595
8%
531
70%
531
20%
1100
August1st to 15thNight
67%
539
8%
1711
9%
536
67%
536
20%
1164
August16th to endNight
64%
619
12%
1956
12%
619
64%
619
19%
1376
September1st to 15thNight
61%
720
11%
1980
10%
720
61%
720
21%
1419
September16th to endNight
59%
717
19%
1980
13%
717
65%
717
23%
1348
October1st to 15thNight
60%
720
27%
1980
22%
720
65%
720
33%
1196
October16th to endNight
57%
768
32%
2301
27%
768
66%
768
36%
1290
November1st to 15thNight
50%
760
30%
2318
25%
760
60%
760
34%
1277
November16th to endNight
46%
780
29%
2535
21%
780
59%
780
29%
1414
December1st to 15thNight
43%
736
25%
2391
21%
736
52%
736
25%
1439
December16th to endNight
42%
768
23%
2496
16%
768
53%
768
22%
1534

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
8%424435%5%6%9%44%
48594
Night
9%42443446%8%46%
48093
TransparencyDay
35%9%13%18%15%6%
48295
Night
33%7%14%19%16%7%
47896
SeeingDay
9%9%12%22%28%18%
5841
Night
9%16%14%25%26%7%
15983

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%244245%5%7%42%
1611
16th to endDay
14%42442445%5%47%
1843
February1st to 15thDay
15%5%24422345%50%
1750
16th to endDay
12%5%24323345%52%
1580
March1st to 15thDay
7%42332335%8%53%
1944
16th to endDay
8%3144235%47%55%
2111
April1st to 15thDay
7%324425%45%8%52%
1972
16th to endDay
6%31432235%8%59%
2205
May1st to 15thDay
5%31331346%9%56%
2331
16th to endDay
43234345%7%10%50%
2431
June1st to 15thDay
8%425%5%37%6%9%12%36%
2340
16th to endDay
8%325%5%36%8%9%13%34%
2340
July1st to 15thDay
7%415%6%48%8%9%13%29%
2340
16th to endDay
7%435%7%47%9%9%13%26%
2465
August1st to 15thDay
11%325%6%5%8%8%11%11%25%
2234
16th to endDay
9%6%26%6%36%7%9%10%29%
2232
September1st to 15thDay
8%5%36%7%46%7%8%12%28%
1980
16th to endDay
8%5%26%6%46%6%7%10%36%
1980
October1st to 15thDay
6%3245%235%5%9%51%
1980
16th to endDay
7%314424346%56%
1923
November1st to 15thDay
7%31321335%8%59%
1868
16th to endDay
9%413323347%56%
1755
December1st to 15thDay
11%6%2443445%6%45%
1651
16th to endDay
11%6%35%4245%6%7%41%
1728
January1st to 15thNight
13%6%25%424448%43%
2327
16th to endNight
15%6%35%423346%43%
2379
February1st to 15thNight
14%5%2432333451%
2103
16th to endNight
12%5%24424345%49%
1893
March1st to 15thNight
8%43432335%8%52%
2016
16th to endNight
8%413424247%56%
2112
April1st to 15thNight
8%425%4335%5%7%50%
1976
16th to endNight
5%313323348%60%
1764
May1st to 15thNight
6%3233234410%55%
1619
16th to endNight
42134245%6%11%54%
1682
June1st to 15thNight
9%415%4345%8%13%40%
1620
16th to endNight
6%5%15%5%36%5%8%12%39%
1620
July1st to 15thNight
6%3245%346%9%16%38%
1620
16th to endNight
5%415%6%48%8%10%14%30%
1703
August1st to 15thNight
7%425%6%36%6%9%14%33%
1722
16th to endNight
7%6%26%6%46%7%8%10%32%
1956
September1st to 15thNight
8%6%25%7%46%6%8%13%29%
1980
16th to endNight
9%5%26%6%35%6%7%8%36%
1980
October1st to 15thNight
5%4245%35%447%52%
1980
16th to endNight
7%42332445%5%55%
2301
November1st to 15thNight
6%414434446%55%
2318
16th to endNight
9%425%323446%53%
2535
December1st to 15thNight
11%6%245%33447%46%
2391
16th to endNight
11%6%345%2445%7%44%
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
38%6%10%17%16%10%
1612
16th to endDay
37%5%9%15%21%10%
1843
February1st to 15thDay
37%37%15%20%15%
1752
16th to endDay
34%5%9%13%25%10%
1580
March1st to 15thDay
27%6%11%21%24%8%
1944
16th to endDay
30%6%12%20%19%11%
2112
April1st to 15thDay
31%7%8%20%22%9%
1972
16th to endDay
25%6%12%25%21%8%
2205
May1st to 15thDay
25%7%11%25%20%9%
2331
16th to endDay
29%11%15%23%16%3
2435
June1st to 15thDay
38%14%18%21%5%
2340
16th to endDay
39%13%20%19%6%
2340
July1st to 15thDay
41%16%23%15%1
2201
16th to endDay
43%16%22%14%2
2310
August1st to 15thDay
46%18%20%12%2
2221
16th to endDay
46%16%19%12%4
2232
September1st to 15thDay
49%14%16%11%6%1
1980
16th to endDay
42%11%13%17%11%3
1980
October1st to 15thDay
30%8%11%18%18%11%
1980
16th to endDay
28%5%8%14%24%17%
1923
November1st to 15thDay
23%5%10%22%24%13%
1868
16th to endDay
28%5%8%18%24%13%
1755
December1st to 15thDay
37%6%9%19%19%7%
1651
16th to endDay
38%7%9%22%13%8%
1728
January1st to 15thNight
39%49%16%19%9%
2327
16th to endNight
42%37%12%22%11%
2379
February1st to 15thNight
35%46%15%21%15%
2112
16th to endNight
37%47%16%22%11%
1893
March1st to 15thNight
30%311%23%20%9%
2016
16th to endNight
29%5%11%21%20%11%
2112
April1st to 15thNight
31%6%10%19%23%9%
1976
16th to endNight
23%411%28%23%8%
1764
May1st to 15thNight
25%6%13%24%19%10%
1620
16th to endNight
23%8%19%25%19%3
1684
June1st to 15thNight
32%10%22%26%6%
1620
16th to endNight
34%10%24%21%7%
1620
July1st to 15thNight
30%14%30%21%3
1530
16th to endNight
36%17%28%14%3
1595
August1st to 15thNight
35%16%29%15%2
1711
16th to endNight
41%14%22%16%4
1956
September1st to 15thNight
42%12%22%15%5%1
1980
16th to endNight
41%8%16%19%10%3
1980
October1st to 15thNight
30%7%13%16%19%11%
1980
16th to endNight
29%47%16%24%17%
2301
November1st to 15thNight
28%48%22%24%11%
2318
16th to endNight
31%49%18%20%15%
2535
December1st to 15thNight
36%5%10%24%16%6%
2391
16th to endNight
38%5%9%23%14%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
14%8%33%24%12%6%
90
16th to endDay
16%15%30%28%9%
96
February1st to 15thDay
10%14%24%32%18%
90
16th to endDay
7%6%38%32%14%1
81
March1st to 15thDay
9%14%23%35%14%1
234
16th to endDay
10%14%20%29%21%3
288
April1st to 15thDay
8%14%25%25%23%2
270
16th to endDay
6%11%15%32%27%6%
270
May1st to 15thDay
8%13%10%31%24%11%
288
16th to endDay
6%10%6%20%32%23%
331
June1st to 15thDay
9%9%216%35%26%
315
16th to endDay
7%10%312%33%31%
315
July1st to 15thDay
5%6%39%26%47%
305
16th to endDay
7%9%49%35%32%
326
August1st to 15thDay
15%5%411%30%33%
313
16th to endDay
10%4310%37%33%
332
September1st to 15thDay
13%5%8%15%28%28%
315
16th to endDay
13%6%5%15%37%22%
314
October1st to 15thDay
7%6%13%25%34%11%
315
16th to endDay
7%6%18%36%24%6%
336
November1st to 15thDay
8%8%10%36%25%9%
286
16th to endDay
7%218%39%24%7%
135
December1st to 15thDay
5%5%25%40%22%3
100
16th to endDay
16%418%35%18%6%
96
January1st to 15thNight
12%22%25%25%12%1
720
16th to endNight
13%22%23%27%12%
768
February1st to 15thNight
14%21%21%27%13%1
704
16th to endNight
13%21%21%34%8%
631
March1st to 15thNight
10%21%22%31%14%1
720
16th to endNight
9%20%18%29%20%1
768
April1st to 15thNight
9%20%15%31%21%1
718
16th to endNight
5%19%15%28%29%2
570
May1st to 15thNight
6%18%11%35%26%3
540
16th to endNight
6%17%6%19%41%7%
563
June1st to 15thNight
7%17%316%41%13%
540
16th to endNight
7%17%314%34%22%
540
July1st to 15thNight
5%12%29%36%33%
510
16th to endNight
316%18%42%26%
564
August1st to 15thNight
7%9%37%47%24%
539
16th to endNight
8%8%315%37%26%
619
September1st to 15thNight
9%9%5%17%39%19%
720
16th to endNight
10%8%7%26%38%7%
717
October1st to 15thNight
7%9%14%33%31%3
720
16th to endNight
8%10%17%33%28%2
768
November1st to 15thNight
7%15%20%31%21%2
760
16th to endNight
10%17%20%31%18%1
780
December1st to 15thNight
10%19%19%26%22%
736
16th to endNight
12%21%17%29%17%
768
Page generated at 2017-12-05 10:19:01. Version ac04

Copyright 2017 A. Danko


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