Edisto Beach State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Edisto Beach State Park clear sky chart from 2005-11-05 to 2017-09-22.

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
55%
15967
21%
46948
16%
15926
61%
15926
28%
29796

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
36%
718
20%
2327
10%
716
49%
716
23%
1444
January16th to endNight
36%
768
22%
2496
14%
768
47%
768
25%
1513
February1st to 15thNight
41%
704
21%
2230
14%
701
52%
701
25%
1379
February16th to endNight
42%
631
25%
1809
14%
631
53%
631
27%
1151
March1st to 15thNight
49%
720
27%
1980
17%
720
57%
720
35%
1207
March16th to endNight
51%
768
21%
2112
14%
768
57%
768
33%
1313
April1st to 15thNight
55%
718
24%
1916
15%
718
61%
718
37%
1159
April16th to endNight
59%
720
26%
1800
15%
720
62%
720
41%
1101
May1st to 15thNight
62%
561
22%
1642
14%
561
65%
561
34%
986
May16th to endNight
70%
561
19%
1683
16%
561
70%
561
32%
1012
June1st to 15thNight
72%
540
13%
1620
11%
540
73%
540
27%
1040
June16th to endNight
75%
540
12%
1620
11%
540
75%
540
25%
1070
July1st to 15thNight
70%
510
13%
1530
12%
510
70%
510
27%
976
July16th to endNight
71%
564
10%
1595
9%
531
73%
531
24%
1089
August1st to 15thNight
71%
539
13%
1609
12%
536
71%
536
21%
1122
August16th to endNight
62%
728
12%
1874
10%
728
62%
728
18%
1429
September1st to 15thNight
66%
720
17%
1951
15%
720
66%
720
25%
1364
September16th to endNight
56%
685
13%
1892
12%
685
57%
685
20%
1373
October1st to 15thNight
59%
660
26%
1950
26%
660
63%
660
31%
1202
October16th to endNight
59%
704
31%
2112
27%
704
68%
704
36%
1203
November1st to 15thNight
57%
700
30%
2101
25%
700
65%
700
37%
1184
November16th to endNight
49%
720
26%
2263
20%
720
58%
720
30%
1329
December1st to 15thNight
45%
720
21%
2340
16%
720
52%
720
23%
1499
December16th to endNight
41%
768
22%
2496
17%
768
49%
768
21%
1651

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%42443446%8%44%
47929
Night
10%5%25%5%245%6%8%44%
47148
TransparencyDay
35%8%15%20%14%4
47630
Night
37%7%13%19%15%6%
46951
SeeingDay
12%215%25%31%12%
5800
Night
12%418%28%27%8%
15972

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%245%3445%7%43%
1611
16th to endDay
15%6%24413346%46%
1728
February1st to 15thDay
14%6%25%423345%44%
1629
16th to endDay
12%5%2442335%5%49%
1664
March1st to 15thDay
11%5%2331435%7%51%
1980
16th to endDay
11%423434448%49%
2111
April1st to 15thDay
8%32332335%8%54%
2032
16th to endDay
6%313424348%56%
2160
May1st to 15thDay
7%323425%5%7%8%49%
2317
16th to endDay
8%413425%5%7%9%46%
2431
June1st to 15thDay
7%3245%35%6%9%11%40%
2340
16th to endDay
6%415%5%36%5%8%12%39%
2340
July1st to 15thDay
7%3246%37%7%7%10%38%
2340
16th to endDay
8%435%6%46%7%7%11%34%
2465
August1st to 15thDay
8%325%6%36%8%9%12%30%
2340
16th to endDay
12%6%37%6%36%7%7%10%29%
2315
September1st to 15thDay
11%5%25%5%345%7%9%39%
2005
16th to endDay
14%7%25%5%345%7%8%34%
1881
October1st to 15thDay
12%414323436%52%
1680
16th to endDay
9%323323335%58%
1760
November1st to 15thDay
9%414423336%56%
1757
16th to endDay
10%424323345%54%
1695
December1st to 15thDay
12%6%35%33425%6%45%
1620
16th to endDay
13%6%24434347%44%
1728
January1st to 15thNight
10%6%35%6%3445%6%43%
2327
16th to endNight
13%5%25%423345%46%
2496
February1st to 15thNight
14%5%2442444447%
2223
16th to endNight
11%5%35%42445%6%45%
1809
March1st to 15thNight
9%324425%45%8%49%
1980
16th to endNight
11%5%25%423345%51%
2112
April1st to 15thNight
9%414324447%53%
1916
16th to endNight
7%324325%45%9%52%
1800
May1st to 15thNight
5%5%24325%46%8%50%
1641
16th to endNight
6%3244245%7%10%46%
1682
June1st to 15thNight
8%4245%36%7%8%13%35%
1620
16th to endNight
5%4235%47%7%9%14%35%
1620
July1st to 15thNight
7%5%35%435%6%8%12%37%
1620
16th to endNight
7%425%7%46%7%9%11%32%
1703
August1st to 15thNight
8%425%6%47%9%10%11%29%
1620
16th to endNight
11%6%37%7%36%6%8%10%26%
1874
September1st to 15thNight
10%5%26%6%35%5%7%10%37%
1951
16th to endNight
15%7%35%6%36%5%7%8%30%
1892
October1st to 15thNight
13%5%24423446%48%
1950
16th to endNight
9%324324435%57%
2112
November1st to 15thNight
9%414313347%54%
2101
16th to endNight
11%5%24423345%51%
2263
December1st to 15thNight
13%6%25%5%34446%42%
2340
16th to endNight
15%6%36%5%34446%39%
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%410%19%19%5%
1612
16th to endDay
39%38%19%21%6%
1728
February1st to 15thDay
41%48%16%22%8%
1631
16th to endDay
37%48%21%21%7%
1664
March1st to 15thDay
32%411%22%20%8%
1980
16th to endDay
33%7%12%23%17%6%
2112
April1st to 15thDay
28%5%13%25%18%7%
2032
16th to endDay
26%5%13%25%20%8%
2160
May1st to 15thDay
30%8%14%26%16%3
2317
16th to endDay
31%9%19%26%12%
2435
June1st to 15thDay
33%11%24%22%8%
2340
16th to endDay
34%13%20%23%7%
2340
July1st to 15thDay
34%12%24%21%5%1
2201
16th to endDay
38%15%24%17%3
2310
August1st to 15thDay
39%14%20%18%6%
2327
16th to endDay
45%13%20%16%3
2315
September1st to 15thDay
40%9%18%17%11%2
2005
16th to endDay
44%9%15%16%10%3
1881
October1st to 15thDay
33%5%12%18%21%8%
1680
16th to endDay
30%47%19%26%11%
1760
November1st to 15thDay
30%49%19%24%11%
1757
16th to endDay
33%5%8%20%21%9%
1695
December1st to 15thDay
40%5%11%20%14%7%
1620
16th to endDay
39%6%11%21%15%6%
1728
January1st to 15thNight
40%410%17%18%7%
2327
16th to endNight
39%39%15%22%9%
2496
February1st to 15thNight
39%47%19%17%11%
2232
16th to endNight
38%5%8%15%21%9%
1809
March1st to 15thNight
32%6%12%21%18%9%
1980
16th to endNight
35%413%19%17%8%
2112
April1st to 15thNight
31%5%11%22%21%8%
1916
16th to endNight
29%5%12%21%22%7%
1800
May1st to 15thNight
31%7%15%21%20%3
1642
16th to endNight
30%9%18%28%11%1
1684
June1st to 15thNight
36%9%22%23%7%
1620
16th to endNight
34%14%21%22%6%
1620
July1st to 15thNight
34%11%25%22%41
1530
16th to endNight
38%12%22%21%3
1595
August1st to 15thNight
39%15%20%18%5%
1609
16th to endNight
48%13%17%17%2
1874
September1st to 15thNight
39%12%16%17%11%1
1951
16th to endNight
48%9%15%15%10%1
1892
October1st to 15thNight
37%410%19%19%8%
1950
16th to endNight
30%49%17%24%13%
2112
November1st to 15thNight
30%48%21%24%11%
2101
16th to endNight
34%49%17%22%11%
2263
December1st to 15thNight
41%6%12%17%15%6%
2340
16th to endNight
45%5%8%19%13%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
15%10%27%26%10%10%
90
16th to endDay
15%7%39%27%10%
96
February1st to 15thDay
8%16%30%35%8%
90
16th to endDay
11%6%42%32%6%
165
March1st to 15thDay
11%432%30%19%1
270
16th to endDay
13%425%31%18%5%
288
April1st to 15thDay
11%5%22%32%20%7%
270
16th to endDay
4218%31%29%12%
270
May1st to 15thDay
7%221%31%29%7%
288
16th to endDay
11%19%20%36%20%
331
June1st to 15thDay
8%7%23%40%19%
315
16th to endDay
8%7%23%39%21%
315
July1st to 15thDay
7%418%46%22%
305
16th to endDay
9%416%52%16%
326
August1st to 15thDay
10%418%48%17%
313
16th to endDay
16%313%41%24%
332
September1st to 15thDay
15%18%20%38%15%
315
16th to endDay
17%7%23%34%16%
278
October1st to 15thDay
20%215%29%21%10%
255
16th to endDay
9%318%28%28%11%
272
November1st to 15thDay
14%6%20%26%27%6%
265
16th to endDay
9%327%32%21%5%
165
December1st to 15thDay
20%132%27%16%2
90
16th to endDay
23%416%30%23%1
96
January1st to 15thNight
14%9%32%28%13%1
720
16th to endNight
15%10%33%30%9%
768
February1st to 15thNight
15%10%27%34%11%
704
16th to endNight
14%6%30%38%10%
631
March1st to 15thNight
11%5%29%38%15%1
720
16th to endNight
13%422%34%22%2
768
April1st to 15thNight
10%5%23%33%22%4
718
16th to endNight
9%420%30%27%7%
720
May1st to 15thNight
7%220%35%25%9%
562
16th to endNight
7%112%23%34%20%
563
June1st to 15thNight
11%426%41%16%
540
16th to endNight
7%6%25%37%22%
540
July1st to 15thNight
9%7%20%47%15%
510
16th to endNight
8%219%55%13%
564
August1st to 15thNight
11%317%51%15%
539
16th to endNight
14%8%16%40%20%
728
September1st to 15thNight
11%16%20%45%14%
720
16th to endNight
18%111%20%37%11%
685
October1st to 15thNight
15%214%28%29%9%
660
16th to endNight
9%419%28%30%7%
704
November1st to 15thNight
11%420%30%28%4
700
16th to endNight
14%7%25%29%20%3
720
December1st to 15thNight
15%5%26%29%17%4
720
16th to endNight
17%7%27%32%14%1
768
Page generated at 2017-09-23 06:43:47. Version ac04

Copyright 2017 A. Danko


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