Arkadelphia
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Arkadelphia clear sky chart from 2005-11-05 to 2018-03-11.

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
49%
16368
26%
49185
18%
16324
56%
16324
32%
28958

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
32%
973
27%
2522
10%
970
43%
970
29%
1620
January16th to endNight
32%
1040
29%
2704
11%
1040
42%
1040
32%
1706
February1st to 15thNight
29%
948
21%
2477
7%
945
37%
945
28%
1631
February16th to endNight
26%
615
26%
1981
11%
615
39%
615
24%
1202
March1st to 15thNight
30%
573
23%
2101
14%
573
42%
573
22%
1284
March16th to endNight
37%
576
21%
2112
16%
576
46%
576
24%
1258
April1st to 15thNight
35%
539
26%
1821
16%
539
50%
539
32%
986
April16th to endNight
40%
540
26%
1800
19%
540
53%
540
31%
1027
May1st to 15thNight
47%
540
21%
1742
17%
540
56%
540
27%
1053
May16th to endNight
51%
563
22%
1685
18%
561
58%
561
32%
1027
June1st to 15thNight
75%
540
22%
1620
21%
540
79%
540
42%
874
June16th to endNight
74%
540
25%
1620
25%
540
77%
540
43%
865
July1st to 15thNight
74%
510
18%
1530
20%
510
75%
510
38%
880
July16th to endNight
83%
564
25%
1594
29%
531
83%
531
44%
853
August1st to 15thNight
79%
539
26%
1646
30%
536
81%
536
46%
854
August16th to endNight
74%
573
24%
1910
30%
573
74%
573
32%
1090
September1st to 15thNight
70%
540
25%
1800
26%
540
72%
540
35%
1004
September16th to endNight
71%
576
33%
1992
34%
576
74%
576
38%
1033
October1st to 15thNight
62%
720
31%
2160
23%
720
67%
720
39%
1202
October16th to endNight
53%
768
38%
2304
25%
768
63%
768
43%
1207
November1st to 15thNight
51%
760
29%
2280
21%
760
59%
760
35%
1315
November16th to endNight
42%
816
32%
2409
21%
816
53%
816
32%
1436
December1st to 15thNight
37%
975
23%
2671
12%
975
45%
975
29%
1726
December16th to endNight
32%
1040
23%
2704
10%
1040
40%
1040
26%
1825

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
14%5%2443445%6%43%
49421
Night
12%424323346%50%
49380
TransparencyDay
40%410%21%18%4
49121
Night
34%310%22%22%7%
49185
SeeingDay
14%5%20%27%24%8%
6194
Night
15%7%22%31%20%2
16370

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
20%5%2432323446%
1746
16th to endDay
20%5%2432223448%
1872
February1st to 15thDay
20%5%24323335%43%
1716
16th to endDay
23%8%35%42332439%
1788
March1st to 15thDay
21%6%2431335%5%42%
2095
16th to endDay
17%8%35%424345%39%
2110
April1st to 15thDay
15%5%24423346%47%
2125
16th to endDay
15%6%25%5%2435%5%43%
2160
May1st to 15thDay
17%6%35%5%35%5%46%37%
2207
16th to endDay
10%5%36%6%46%5%6%9%35%
2430
June1st to 15thDay
6%425%7%47%46%8%41%
2340
16th to endDay
7%4246%46%7%7%8%41%
2340
July1st to 15thDay
8%5%146%47%6%7%9%36%
2340
16th to endDay
6%3246%47%7%7%10%39%
2466
August1st to 15thDay
6%315%5%45%7%8%10%41%
2301
16th to endDay
8%5%26%6%46%6%6%8%37%
2292
September1st to 15thDay
14%415%445%45%6%43%
2160
16th to endDay
9%324425%446%52%
1953
October1st to 15thDay
12%425%424336%50%
1800
16th to endDay
14%312211245%59%
1920
November1st to 15thDay
14%5%23312235%53%
1908
16th to endDay
17%7%24412235%48%
1871
December1st to 15thDay
19%6%2442434444%
1609
16th to endDay
20%8%25%323345%41%
1872
January1st to 15thNight
19%5%2432223450%
2522
16th to endNight
18%42321233351%
2704
February1st to 15thNight
18%5%25%323235%47%
2467
16th to endNight
19%5%23322246%46%
1981
March1st to 15thNight
19%5%34422345%45%
2101
16th to endNight
15%6%24324335%46%
2112
April1st to 15thNight
11%32431345%8%52%
1821
16th to endNight
11%424424335%52%
1800
May1st to 15thNight
13%5%14425%447%46%
1741
16th to endNight
8%425%434449%46%
1683
June1st to 15thNight
32244235%6%9%55%
1620
16th to endNight
5%2233245%6%10%54%
1620
July1st to 15thNight
43145%35%6%6%12%45%
1620
16th to endNight
3113425%47%12%52%
1702
August1st to 15thNight
42124245%6%12%54%
1656
16th to endNight
7%425%4346%7%11%44%
1910
September1st to 15thNight
8%41441436%8%52%
1800
16th to endNight
6%41331445%6%56%
1992
October1st to 15thNight
10%413423345%56%
2160
16th to endNight
11%31321223363%
2304
November1st to 15thNight
11%313324345%54%
2280
16th to endNight
18%6%1231223354%
2409
December1st to 15thNight
18%5%33422335%46%
2671
16th to endNight
20%7%24313345%42%
2704

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
41%26%22%20%6%
1747
16th to endDay
41%1421%25%5%
1872
February1st to 15thDay
43%37%22%18%4
1717
16th to endDay
50%26%17%18%5%
1788
March1st to 15thDay
44%29%18%17%7%
2095
16th to endDay
46%49%22%16%1
2112
April1st to 15thDay
39%39%22%18%7%
2125
16th to endDay
43%38%20%19%3
2160
May1st to 15thDay
46%5%8%17%17%4
2207
16th to endDay
42%7%14%21%11%1
2434
June1st to 15thDay
39%6%11%24%16%1
2340
16th to endDay
36%7%12%23%18%2
2340
July1st to 15thDay
37%7%16%24%13%
2201
16th to endDay
35%8%17%23%14%1
2311
August1st to 15thDay
34%9%15%24%14%2
2287
16th to endDay
41%7%15%20%13%3
2292
September1st to 15thDay
40%5%10%17%18%7%
2160
16th to endDay
32%410%21%22%7%
1953
October1st to 15thDay
36%39%18%21%10%
1800
16th to endDay
28%25%20%29%13%
1920
November1st to 15thDay
33%37%22%25%7%
1908
16th to endDay
40%16%17%27%6%
1871
December1st to 15thDay
43%39%18%17%7%
1609
16th to endDay
46%28%20%17%4
1872
January1st to 15thNight
39%15%20%26%5%
2522
16th to endNight
37%26%18%26%7%
2704
February1st to 15thNight
41%27%21%20%5%
2477
16th to endNight
40%27%21%19%8%
1981
March1st to 15thNight
42%37%16%19%9%
2101
16th to endNight
40%39%21%21%3
2112
April1st to 15thNight
30%311%22%20%11%
1821
16th to endNight
34%48%24%24%5%
1800
May1st to 15thNight
37%5%9%20%19%7%
1742
16th to endNight
35%5%16%26%14%1
1685
June1st to 15thNight
23%7%11%33%21%3
1620
16th to endNight
24%5%13%27%24%4
1620
July1st to 15thNight
29%6%19%27%15%1
1530
16th to endNight
22%7%18%31%18%2
1594
August1st to 15thNight
21%5%18%30%19%3
1646
16th to endNight
30%7%15%24%18%3
1910
September1st to 15thNight
29%6%13%21%21%8%
1800
16th to endNight
26%48%23%25%10%
1992
October1st to 15thNight
30%29%19%23%14%
2160
16th to endNight
26%2418%32%15%
2304
November1st to 15thNight
32%38%20%25%10%
2280
16th to endNight
36%25%16%30%8%
2409
December1st to 15thNight
41%29%19%19%7%
2671
16th to endNight
44%28%20%17%5%
2704

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
20%14%40%20%5%
135
16th to endDay
17%22%36%16%5%1
144
February1st to 15thDay
24%14%40%15%4
135
16th to endDay
30%21%35%9%3
120
March1st to 15thDay
29%17%38%13%
121
16th to endDay
20%18%23%29%7%
96
April1st to 15thDay
21%12%31%20%13%
244
16th to endDay
22%8%26%21%18%2
270
May1st to 15thDay
16%7%34%26%12%3
344
16th to endDay
11%5%28%34%15%5%
517
June1st to 15thDay
9%113%32%33%9%
495
16th to endDay
7%114%35%31%8%
495
July1st to 15thDay
7%113%36%32%8%
475
16th to endDay
5%426%44%18%
515
August1st to 15thDay
7%18%29%37%15%
454
16th to endDay
17%423%36%16%
332
September1st to 15thDay
12%18%24%38%15%
315
16th to endDay
5%113%38%30%10%
159
October1st to 15thDay
6%225%38%18%7%
135
16th to endDay
18%431%25%13%4
144
November1st to 15thDay
24%8%23%25%14%2
135
16th to endDay
25%11%30%17%11%3
135
December1st to 15thDay
20%17%30%18%11%2
135
16th to endDay
29%16%34%15%2
144
January1st to 15thNight
23%12%29%27%7%
975
16th to endNight
20%12%33%29%4
1040
February1st to 15thNight
22%13%31%29%4
948
16th to endNight
22%13%33%25%4
615
March1st to 15thNight
22%10%32%29%5%
573
16th to endNight
19%10%30%31%7%
576
April1st to 15thNight
13%11%37%25%11%
539
16th to endNight
13%6%34%30%13%
540
May1st to 15thNight
15%425%38%13%1
540
16th to endNight
10%326%34%22%3
563
June1st to 15thNight
319%42%38%4
540
16th to endNight
5%110%35%40%7%
540
July1st to 15thNight
5%8%31%46%7%
510
16th to endNight
3328%50%12%
564
August1st to 15thNight
5%6%28%46%12%
539
16th to endNight
9%430%46%8%
573
September1st to 15thNight
11%10%28%42%6%
540
16th to endNight
9%110%33%40%5%
576
October1st to 15thNight
12%316%32%30%4
720
16th to endNight
13%6%23%32%22%2
768
November1st to 15thNight
13%8%21%35%19%1
760
16th to endNight
19%9%24%28%16%
816
December1st to 15thNight
23%8%26%32%8%
975
16th to endNight
24%10%27%30%7%
1040
Page generated at 2018-03-12 12:28:05. Version ac04

Copyright 2018 A. Danko


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