Palmetto State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Palmetto State Park 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
50%
23682
24%
74304
17%
23629
57%
23629
31%
43548

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
37%
946
27%
2458
12%
946
46%
946
34%
1543
January11th to 20thNight
38%
915
25%
2379
11%
915
45%
915
32%
1517
January21st to endNight
36%
904
28%
2488
13%
904
46%
904
29%
1590
February1st to 10thNight
32%
720
24%
2160
11%
720
42%
720
24%
1376
February11th to 20thNight
31%
704
21%
2098
10%
700
40%
700
27%
1313
February21st to endNight
23%
574
24%
1758
7%
574
37%
574
22%
1124
March1st to 10thNight
30%
540
24%
1980
10%
540
45%
540
21%
1212
March11th to 20thNight
28%
540
20%
1980
12%
540
38%
540
20%
1257
March21st to endNight
31%
594
25%
2178
15%
594
45%
594
26%
1241
April1st to 10thNight
27%
540
22%
1980
12%
540
43%
540
24%
1157
April11th to 20thNight
32%
533
21%
1953
13%
533
45%
533
24%
1160
April21st to endNight
28%
540
26%
1713
13%
540
45%
540
26%
1055
May1st to 10thNight
32%
540
22%
1620
16%
540
40%
540
27%
1028
May11th to 20thNight
42%
531
22%
1594
19%
531
50%
531
30%
983
May21st to endNight
48%
583
21%
1745
16%
582
57%
582
31%
1057
June1st to 10thNight
69%
540
22%
1620
23%
540
73%
540
43%
863
June11th to 20thNight
63%
540
24%
1620
21%
540
72%
540
46%
832
June21st to endNight
72%
540
20%
1620
23%
540
75%
540
34%
964
July1st to 10thNight
72%
525
17%
1575
19%
525
74%
525
34%
941
July11th to 20thNight
81%
522
25%
1566
26%
522
85%
522
50%
779
July21st to endNight
81%
591
24%
1673
27%
558
84%
558
51%
832
August1st to 10thNight
86%
537
27%
1601
29%
534
89%
534
60%
728
August11th to 20thNight
81%
534
24%
1730
27%
534
83%
534
37%
944
August21st to endNight
80%
594
18%
2119
21%
594
81%
594
35%
1140
September1st to 10thNight
74%
540
20%
1980
23%
540
75%
540
31%
1090
September11th to 20thNight
74%
540
22%
1980
25%
540
75%
540
28%
1148
September21st to endNight
68%
540
25%
1980
26%
540
71%
540
35%
1046
October1st to 10thNight
78%
540
36%
1980
38%
540
80%
540
44%
927
October11th to 20thNight
59%
670
32%
2110
25%
670
65%
670
36%
1187
October21st to endNight
52%
792
33%
2376
22%
792
59%
792
39%
1295
November1st to 10thNight
57%
740
28%
2220
21%
740
61%
740
35%
1322
November11th to 20thNight
50%
807
27%
2327
17%
807
56%
807
35%
1371
November21st to endNight
40%
950
27%
2470
13%
950
48%
950
30%
1601
December1st to 10thNight
44%
950
29%
2470
16%
950
50%
950
31%
1605
December11th to 20thNight
35%
949
24%
2888
12%
948
41%
948
22%
1912
December21st to endNight
39%
1037
16%
4315
12%
1026
46%
1026
22%
2408

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%6%8%44%
74891
Night
13%5%2442445%7%50%
74876
TransparencyDay
38%6%11%20%17%8%
74616
Night
34%5%12%21%18%10%
74671
SeeingDay
12%6%18%27%26%10%
13652
Night
15%6%23%36%18%2
23696

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
17%6%25%433345%46%
1707
11th to 20thDay
21%6%25%423245%45%
1643
21st to endDay
16%6%35%32344449%
1881
February1st to 10thDay
22%8%24323345%43%
1800
11th to 20thDay
21%7%35%323445%41%
1749
21st to endDay
19%7%34424445%45%
1497
March1st to 10thDay
20%7%36%434346%39%
1980
11th to 20thDay
16%6%36%5%3445%6%42%
1980
21st to endDay
17%7%34424446%46%
2178
April1st to 10thDay
15%7%36%6%345%47%41%
1980
11th to 20thDay
16%7%36%6%34446%42%
1956
21st to endDay
14%6%35%5%34446%45%
2240
May1st to 10thDay
12%6%36%5%45%5%6%7%40%
2340
11th to 20thDay
11%7%36%6%36%6%6%8%39%
2302
21st to endDay
11%6%36%6%36%6%7%10%36%
2531
June1st to 10thDay
5%3146%46%7%8%9%46%
2340
11th to 20thDay
5%325%7%46%6%7%11%45%
2340
21st to endDay
6%6%37%6%47%7%9%11%34%
2340
July1st to 10thDay
9%6%36%7%5%6%6%7%9%36%
2340
11th to 20thDay
43246%46%7%7%12%45%
2340
21st to endDay
43246%45%6%8%12%46%
2546
August1st to 10thDay
22135%36%6%6%11%54%
2328
11th to 20thDay
5%225%5%47%7%8%10%46%
2167
21st to endDay
6%425%6%5%6%7%8%11%40%
2234
September1st to 10thDay
6%5%27%7%46%5%7%8%42%
1980
11th to 20thDay
10%7%36%6%45%6%6%7%40%
1980
21st to endDay
7%425%436%5%6%9%47%
1980
October1st to 10thDay
6%3245%345%6%9%52%
1980
11th to 20thDay
13%6%234345%47%48%
1830
21st to endDay
11%414424345%57%
1980
November1st to 10thDay
12%8%25%5%3445%7%45%
1858
11th to 20thDay
12%6%25%5%23447%50%
1848
21st to endDay
18%7%36%434445%43%
1710
December1st to 10thDay
17%7%35%5%34346%42%
1710
11th to 20thDay
17%8%35%5%34445%43%
2161
21st to endDay
16%6%35%423345%50%
3135
January1st to 10thNight
19%6%13323347%49%
2458
11th to 20thNight
18%5%34313335%51%
2379
21st to endNight
19%6%34423435%48%
2488
February1st to 10thNight
20%6%2442445%6%44%
2160
11th to 20thNight
21%8%24322336%47%
2098
21st to endNight
23%5%3442345%6%43%
1758
March1st to 10thNight
17%7%244345%46%43%
1980
11th to 20thNight
17%8%26%5%24446%41%
1980
21st to endNight
15%6%24323346%50%
2178
April1st to 10thNight
12%6%35%43446%7%45%
1980
11th to 20thNight
16%8%245%33347%45%
1953
21st to endNight
13%7%46%5%23447%45%
1713
May1st to 10thNight
13%7%35%5%2446%8%42%
1620
11th to 20thNight
11%5%25%5%35%5%6%9%44%
1593
21st to endNight
10%5%244346%6%13%42%
1745
June1st to 10thNight
441443446%9%58%
1620
11th to 20thNight
332343447%10%58%
1620
21st to endNight
6%5%2445%6%6%6%8%49%
1620
July1st to 10thNight
7%425%5%346%7%11%46%
1620
11th to 20thNight
32133245%6%11%60%
1620
21st to endNight
321433447%13%57%
1772
August1st to 10thNight
11222345%9%70%
1611
11th to 20thNight
4314425%6%7%10%54%
1730
21st to endNight
6%2244345%7%12%51%
2119
September1st to 10thNight
7%5%25%5%345%6%8%51%
1980
11th to 20thNight
8%5%245%45%5%5%9%48%
1980
21st to endNight
7%3245%445%5%9%52%
1980
October1st to 10thNight
432342445%8%61%
1980
11th to 20thNight
12%424433446%54%
2110
21st to endNight
12%41342333461%
2376
November1st to 10thNight
12%5%25%423346%53%
2220
11th to 20thNight
11%5%25%423445%54%
2327
21st to endNight
17%5%35%424347%46%
2470
December1st to 10thNight
17%6%245%33346%47%
2470
11th to 20thNight
19%8%35%433446%42%
3036
21st to endNight
17%6%24323335%51%
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
41%45%15%23%12%
1708
11th to 20thDay
42%36%15%19%15%
1643
21st to endDay
39%45%15%23%14%
1881
February1st to 10thDay
44%46%12%20%14%
1800
11th to 20thDay
45%46%17%17%11%
1759
21st to endDay
42%5%8%15%17%13%
1497
March1st to 10thDay
47%410%13%17%9%
1980
11th to 20thDay
44%47%13%18%13%
1980
21st to endDay
40%310%16%18%12%
2178
April1st to 10thDay
43%5%8%17%16%10%
1980
11th to 20thDay
45%47%15%18%11%
1956
21st to endDay
41%5%5%21%19%9%
2240
May1st to 10thDay
42%7%9%18%16%8%
2340
11th to 20thDay
40%8%9%20%18%4
2306
21st to endDay
41%7%14%21%15%1
2531
June1st to 10thDay
29%10%14%26%19%2
2340
11th to 20thDay
32%7%15%24%18%4
2340
21st to endDay
40%9%15%22%12%2
2340
July1st to 10thDay
41%8%16%24%9%2
2276
11th to 20thDay
30%9%20%24%16%1
2271
21st to endDay
26%10%20%33%10%1
2405
August1st to 10thDay
22%8%17%35%16%1
2314
11th to 20thDay
29%9%20%27%11%3
2167
21st to endDay
34%10%19%24%10%2
2234
September1st to 10thDay
39%8%13%20%15%6%
1980
11th to 20thDay
41%8%12%18%16%5%
1980
21st to endDay
32%6%12%22%17%12%
1980
October1st to 10thDay
28%6%12%22%21%11%
1980
11th to 20thDay
36%5%8%16%19%16%
1830
21st to endDay
30%47%16%24%20%
1980
November1st to 10thDay
38%6%9%18%19%10%
1858
11th to 20thDay
35%411%17%19%14%
1848
21st to endDay
44%48%14%19%12%
1710
December1st to 10thDay
44%48%18%19%7%
1710
11th to 20thDay
43%5%7%10%21%13%
2159
21st to endDay
38%35%18%23%13%
3135
January1st to 10thNight
37%37%16%22%15%
2458
11th to 20thNight
39%26%17%20%15%
2379
21st to endNight
40%3415%20%17%
2488
February1st to 10thNight
42%47%12%18%16%
2160
11th to 20thNight
42%37%16%18%14%
2098
21st to endNight
43%5%6%16%16%14%
1758
March1st to 10thNight
42%5%11%16%17%10%
1980
11th to 20thNight
44%6%8%13%17%13%
1980
21st to endNight
37%411%17%19%13%
2178
April1st to 10thNight
38%5%10%20%16%11%
1980
11th to 20thNight
40%410%15%15%15%
1953
21st to endNight
40%5%9%20%17%9%
1713
May1st to 10thNight
39%6%11%19%15%10%
1620
11th to 20thNight
36%6%12%25%17%4
1594
21st to endNight
33%8%19%26%13%1
1746
June1st to 10thNight
23%7%18%28%22%2
1620
11th to 20thNight
22%5%16%33%20%4
1620
21st to endNight
31%8%19%27%13%2
1620
July1st to 10thNight
29%10%21%30%9%1
1575
11th to 20thNight
17%8%28%32%14%1
1566
21st to endNight
17%8%30%37%9%
1673
August1st to 10thNight
12%6%25%41%15%1
1601
11th to 20thNight
22%12%24%31%9%2
1730
21st to endNight
24%11%26%27%10%3
2119
September1st to 10thNight
30%8%19%24%13%6%
1980
11th to 20thNight
32%9%16%23%15%5%
1980
21st to endNight
29%5%18%21%16%11%
1980
October1st to 10thNight
21%5%11%29%22%11%
1980
11th to 20thNight
31%48%19%20%17%
2110
21st to endNight
28%46%18%22%22%
2376
November1st to 10thNight
33%5%9%19%20%13%
2220
11th to 20thNight
33%5%11%18%20%14%
2327
21st to endNight
39%49%16%18%13%
2470
December1st to 10thNight
39%47%21%18%11%
2470
11th to 20thNight
43%46%11%19%16%
3037
21st to endNight
37%36%14%28%12%
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
22%9%35%23%10%1
270
11th to 20thDay
24%10%23%29%11%2
248
21st to endDay
19%11%34%25%10%
264
February1st to 10thDay
29%12%25%23%10%1
240
11th to 20thDay
27%14%31%19%8%2
240
21st to endDay
27%13%37%22%2
198
March1st to 10thDay
24%10%36%23%7%1
240
11th to 20thDay
16%11%42%23%7%1
240
21st to endDay
19%11%34%28%8%1
264
April1st to 10thDay
19%9%39%23%10%
240
11th to 20thDay
18%14%29%27%11%2
234
21st to endDay
18%10%33%25%12%1
500
May1st to 10thDay
14%10%35%29%10%1
603
11th to 20thDay
14%6%24%35%18%2
625
21st to endDay
11%424%35%23%3
679
June1st to 10thDay
7%111%37%34%10%
630
11th to 20thDay
5%112%40%34%7%
630
21st to endDay
7%38%31%35%15%
630
July1st to 10thDay
7%26%27%40%17%
621
11th to 20thDay
41422%51%19%
618
21st to endDay
31426%47%19%
684
August1st to 10thDay
22324%47%23%
626
11th to 20thDay
5%1325%40%26%
481
21st to endDay
6%3418%29%39%
353
September1st to 10thDay
6%2317%41%31%
270
11th to 20thDay
6%2220%40%30%
270
21st to endDay
10%1323%38%24%
270
October1st to 10thDay
8%110%26%37%18%
270
11th to 20thDay
11%415%30%29%11%
270
21st to endDay
16%8%24%23%22%6%
297
November1st to 10thDay
19%416%35%19%7%
270
11th to 20thDay
18%5%21%31%21%4
270
21st to endDay
25%10%30%20%12%3
270
December1st to 10thDay
21%7%23%30%13%6%
270
11th to 20thDay
22%13%24%29%12%
270
21st to endDay
22%9%31%25%11%2
297
January1st to 10thNight
22%7%29%32%9%
950
11th to 20thNight
21%10%26%34%8%
915
21st to endNight
23%7%28%35%7%
904
February1st to 10thNight
26%9%28%31%5%
720
11th to 20thNight
25%10%32%30%4
704
21st to endNight
28%12%34%24%3
574
March1st to 10thNight
22%10%33%31%3
540
11th to 20thNight
21%7%37%29%6%
540
21st to endNight
18%9%38%30%41
594
April1st to 10thNight
15%9%45%28%3
540
11th to 20thNight
18%9%36%32%6%
533
21st to endNight
17%7%43%24%9%
540
May1st to 10thNight
15%9%42%29%5%
540
11th to 20thNight
14%5%33%37%11%1
531
21st to endNight
10%332%39%15%1
584
June1st to 10thNight
5%216%53%23%1
540
11th to 20thNight
4125%51%17%1
540
21st to endNight
6%311%45%31%5%
540
July1st to 10thNight
6%38%46%33%5%
525
11th to 20thNight
319%47%36%4
522
21st to endNight
38%46%38%5%
591
August1st to 10thNight
116%51%37%4
537
11th to 20thNight
415%49%37%4
534
21st to endNight
7%2436%45%6%
594
September1st to 10thNight
8%15%35%45%6%
540
11th to 20thNight
10%2435%45%4
540
21st to endNight
9%11%34%40%4
540
October1st to 10thNight
5%19%46%35%4
540
11th to 20thNight
12%419%41%22%2
670
21st to endNight
13%7%25%33%21%2
792
November1st to 10thNight
14%5%19%41%20%1
740
11th to 20thNight
14%5%24%39%16%2
807
21st to endNight
19%8%27%31%14%1
950
December1st to 10thNight
21%7%23%37%12%1
950
11th to 20thNight
25%9%26%32%8%
950
21st to endNight
21%8%26%37%9%1
1045
Page generated at 2024-01-10 18:35:21. Version ac07

Copyright 2024 Attilla Danko


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