Congaree National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Congaree National Park clear sky chart from 2005-11-05 to 2017-12-20.

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
50%
16217
22%
48041
15%
16176
57%
16176
28%
30175

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
34%
718
21%
2327
11%
716
48%
716
24%
1422
January16th to endNight
31%
768
24%
2496
15%
768
44%
768
24%
1536
February1st to 15thNight
33%
704
23%
2229
12%
701
48%
701
26%
1364
February16th to endNight
31%
631
27%
1845
13%
631
45%
631
30%
1128
March1st to 15thNight
37%
720
26%
1980
14%
720
46%
720
31%
1223
March16th to endNight
40%
768
20%
2112
11%
768
48%
768
31%
1343
April1st to 15thNight
42%
718
23%
1925
12%
718
49%
718
35%
1170
April16th to endNight
48%
676
24%
1756
14%
676
54%
676
35%
1090
May1st to 15thNight
50%
539
19%
1620
12%
539
55%
539
28%
1009
May16th to endNight
64%
561
19%
1682
14%
561
67%
561
30%
1056
June1st to 15thNight
65%
540
14%
1620
12%
540
66%
540
25%
1086
June16th to endNight
70%
540
14%
1620
13%
540
71%
540
28%
1071
July1st to 15thNight
68%
510
11%
1530
9%
510
69%
510
23%
1048
July16th to endNight
72%
564
11%
1595
10%
531
74%
531
25%
1087
August1st to 15thNight
68%
539
14%
1609
12%
536
68%
536
22%
1127
August16th to endNight
66%
688
15%
1834
12%
688
66%
688
24%
1297
September1st to 15thNight
68%
720
19%
1971
17%
720
68%
720
27%
1325
September16th to endNight
57%
717
18%
1980
16%
717
59%
717
25%
1365
October1st to 15thNight
56%
720
29%
2112
26%
720
62%
720
34%
1244
October16th to endNight
55%
768
35%
2304
28%
768
66%
768
39%
1252
November1st to 15thNight
55%
760
30%
2281
24%
760
64%
760
38%
1271
November16th to endNight
46%
780
28%
2519
21%
780
57%
780
31%
1452
December1st to 15thNight
44%
780
24%
2535
18%
780
55%
780
26%
1573
December16th to endNight
38%
788
23%
2559
18%
788
46%
788
22%
1636

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
12%5%25%5%35%5%5%7%42%
48792
Night
11%5%2442445%7%45%
48240
TransparencyDay
38%7%11%19%17%5%
48493
Night
36%7%11%18%18%7%
48043
SeeingDay
13%417%24%24%14%
6024
Night
14%5%21%33%21%2
16222

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
15%6%24324445%45%
1611
16th to endDay
15%5%235%24345%47%
1728
February1st to 15thDay
15%6%25%323345%46%
1630
16th to endDay
15%5%2442433448%
1628
March1st to 15thDay
13%423423247%49%
1980
16th to endDay
14%425%5%23446%45%
2111
April1st to 15thDay
10%323425%45%7%49%
2023
16th to endDay
9%425%43446%8%47%
2214
May1st to 15thDay
9%5%25%5%35%5%47%44%
2331
16th to endDay
9%6%26%6%36%5%7%8%38%
2431
June1st to 15thDay
9%425%5%46%5%7%10%38%
2340
16th to endDay
6%3245%46%8%8%10%39%
2340
July1st to 15thDay
7%5%26%7%5%7%7%7%10%32%
2340
16th to endDay
6%437%6%47%8%8%11%30%
2465
August1st to 15thDay
10%6%26%6%37%7%7%10%30%
2340
16th to endDay
12%6%26%6%47%5%8%11%29%
2354
September1st to 15thDay
9%5%245%345%6%9%41%
1986
16th to endDay
17%5%25%435%45%6%38%
1980
October1st to 15thDay
16%314423335%51%
1846
16th to endDay
10%41321233460%
1920
November1st to 15thDay
13%423223246%54%
1907
16th to endDay
12%5%145%23336%50%
1768
December1st to 15thDay
16%7%245%24445%41%
1755
16th to endDay
19%6%24423445%41%
1764
January1st to 15thNight
13%6%25%424435%47%
2327
16th to endNight
16%6%2442334446%
2496
February1st to 15thNight
16%414424346%46%
2220
16th to endNight
13%5%25%423346%49%
1845
March1st to 15thNight
11%424424447%48%
1980
16th to endNight
12%42442435%6%47%
2112
April1st to 15thNight
10%423415%447%51%
1925
16th to endNight
9%3245%3445%7%49%
1756
May1st to 15thNight
8%5%246%3446%8%44%
1619
16th to endNight
7%4245%25%5%7%10%44%
1682
June1st to 15thNight
10%4245%45%6%7%11%35%
1620
16th to endNight
5%425%6%35%6%8%10%39%
1620
July1st to 15thNight
7%5%36%5%46%7%8%10%34%
1620
16th to endNight
44347%37%7%9%12%34%
1703
August1st to 15thNight
8%5%27%6%36%7%8%12%32%
1620
16th to endNight
10%5%35%6%46%6%7%12%32%
1834
September1st to 15thNight
8%5%25%5%35%5%6%8%41%
1971
16th to endNight
15%6%26%5%34446%39%
1980
October1st to 15thNight
15%413322345%51%
2112
16th to endNight
9%423312346%57%
2304
November1st to 15thNight
12%413213236%57%
2281
16th to endNight
13%5%13323346%50%
2519
December1st to 15thNight
15%5%23424346%46%
2535
16th to endNight
17%6%34424446%41%
2559

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%49%16%21%6%
1612
16th to endDay
39%37%17%23%8%
1728
February1st to 15thDay
39%37%19%23%6%
1632
16th to endDay
39%36%20%23%6%
1628
March1st to 15thDay
35%48%21%20%9%
1980
16th to endDay
40%6%9%19%19%4
2112
April1st to 15thDay
33%5%11%20%22%7%
2023
16th to endDay
32%5%11%20%21%7%
2214
May1st to 15thDay
37%7%13%20%19%2
2331
16th to endDay
40%8%14%23%12%1
2435
June1st to 15thDay
38%9%17%24%10%
2340
16th to endDay
34%12%17%22%11%1
2340
July1st to 15thDay
41%12%17%18%7%3
2201
16th to endDay
39%14%20%17%7%1
2310
August1st to 15thDay
43%11%15%18%9%
2327
16th to endDay
44%13%16%16%7%1
2354
September1st to 15thDay
37%10%13%16%17%4
1986
16th to endDay
45%5%9%17%16%4
1980
October1st to 15thDay
36%38%20%24%6%
1846
16th to endDay
28%35%18%30%12%
1920
November1st to 15thDay
31%37%19%26%11%
1907
16th to endDay
34%49%18%22%10%
1768
December1st to 15thDay
44%49%17%17%6%
1755
16th to endDay
43%5%8%19%16%7%
1764
January1st to 15thNight
38%5%9%14%25%7%
2327
16th to endNight
40%45%18%21%10%
2496
February1st to 15thNight
38%37%18%20%10%
2229
16th to endNight
36%48%20%21%9%
1845
March1st to 15thNight
35%5%10%18%21%9%
1980
16th to endNight
35%6%11%19%19%6%
2112
April1st to 15thNight
31%5%10%19%23%8%
1925
16th to endNight
32%6%11%19%21%9%
1756
May1st to 15thNight
36%8%14%20%18%2
1620
16th to endNight
33%9%15%26%13%1
1684
June1st to 15thNight
40%9%17%22%9%
1620
16th to endNight
35%12%18%21%10%2
1620
July1st to 15thNight
38%13%19%17%7%3
1530
16th to endNight
34%15%23%15%8%1
1595
August1st to 15thNight
40%13%18%16%9%1
1609
16th to endNight
42%11%20%18%8%
1834
September1st to 15thNight
38%10%13%18%14%5%
1971
16th to endNight
44%6%11%17%15%4
1980
October1st to 15thNight
34%39%19%24%7%
2112
16th to endNight
27%46%19%26%14%
2304
November1st to 15thNight
29%37%17%27%14%
2281
16th to endNight
34%47%16%23%14%
2519
December1st to 15thNight
39%5%9%17%19%8%
2535
16th to endNight
43%49%17%16%8%
2559

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%13%36%22%10%2
90
16th to endDay
14%22%39%18%31
96
February1st to 15thDay
16%21%50%11%1
90
16th to endDay
14%13%34%31%5%
129
March1st to 15thDay
13%10%30%31%12%
270
16th to endDay
12%8%32%25%17%2
288
April1st to 15thDay
14%10%22%24%22%5%
270
16th to endDay
12%322%27%21%11%
270
May1st to 15thDay
11%7%23%26%22%8%
288
16th to endDay
12%412%20%28%22%
331
June1st to 15thDay
11%10%22%31%22%
315
16th to endDay
8%10%27%30%22%
315
July1st to 15thDay
9%6%26%29%27%
305
16th to endDay
8%1421%39%24%
326
August1st to 15thDay
15%17%21%30%23%
313
16th to endDay
15%8%16%28%31%
332
September1st to 15thDay
14%18%22%33%18%
315
16th to endDay
20%111%25%25%14%
314
October1st to 15thDay
18%114%29%25%9%
315
16th to endDay
9%5%20%25%26%12%
336
November1st to 15thDay
19%419%28%23%6%
325
16th to endDay
6%8%23%31%22%6%
148
December1st to 15thDay
20%8%32%27%11%
135
16th to endDay
22%12%28%22%12%
108
January1st to 15thNight
16%11%31%30%8%
720
16th to endNight
19%10%33%32%3
768
February1st to 15thNight
19%11%31%32%4
704
16th to endNight
16%9%36%33%4
631
March1st to 15thNight
14%8%35%32%8%
720
16th to endNight
13%7%33%32%12%
768
April1st to 15thNight
12%11%31%32%12%
718
16th to endNight
11%6%27%37%15%
676
May1st to 15thNight
11%427%39%15%1
540
16th to endNight
10%115%34%34%3
563
June1st to 15thNight
12%111%39%29%5%
540
16th to endNight
7%18%37%37%6%
540
July1st to 15thNight
10%6%38%37%6%
510
16th to endNight
6%17%34%43%6%
564
August1st to 15thNight
11%15%28%45%7%
539
16th to endNight
13%16%27%43%8%
688
September1st to 15thNight
9%18%28%44%6%
720
16th to endNight
19%211%30%33%3
717
October1st to 15thNight
18%217%30%27%4
720
16th to endNight
11%5%22%30%26%2
768
November1st to 15thNight
14%420%37%18%3
760
16th to endNight
15%7%26%28%19%1
780
December1st to 15thNight
18%6%23%35%14%1
780
16th to endNight
21%7%27%33%9%1
788
Page generated at 2017-12-21 07:04:49. Version ac04

Copyright 2017 A. Danko


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