Little Rock
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Rock clear sky chart from 2005-11-05 to 2018-02-22.

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
49%
16346
26%
49037
18%
16301
57%
16301
33%
29011

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%
974
27%
2522
10%
970
43%
970
31%
1605
January16th to endNight
31%
1040
28%
2704
10%
1040
42%
1040
32%
1711
February1st to 15thNight
28%
922
21%
2451
7%
919
37%
919
28%
1617
February16th to endNight
27%
647
28%
1965
11%
647
40%
647
28%
1181
March1st to 15thNight
31%
540
22%
1980
15%
540
41%
540
22%
1207
March16th to endNight
37%
576
21%
2106
15%
576
47%
576
23%
1277
April1st to 15thNight
35%
539
25%
1797
15%
539
51%
539
31%
994
April16th to endNight
40%
540
25%
1800
19%
540
53%
540
32%
1012
May1st to 15thNight
49%
540
20%
1770
16%
540
57%
540
27%
1074
May16th to endNight
53%
563
22%
1685
18%
561
60%
561
31%
1037
June1st to 15thNight
77%
540
25%
1449
22%
540
80%
540
50%
797
June16th to endNight
75%
540
27%
1525
24%
540
78%
540
46%
839
July1st to 15thNight
73%
510
18%
1530
18%
510
76%
510
35%
890
July16th to endNight
84%
564
25%
1594
29%
531
84%
531
41%
883
August1st to 15thNight
79%
539
24%
1670
27%
536
80%
536
42%
893
August16th to endNight
78%
573
24%
1910
30%
573
78%
573
31%
1121
September1st to 15thNight
70%
540
26%
1800
28%
540
73%
540
34%
1018
September16th to endNight
67%
603
33%
1967
32%
603
71%
603
38%
1052
October1st to 15thNight
58%
720
31%
2160
23%
720
63%
720
39%
1202
October16th to endNight
53%
768
38%
2304
25%
768
64%
768
42%
1227
November1st to 15thNight
49%
760
31%
2280
22%
760
58%
760
36%
1291
November16th to endNight
44%
793
31%
2535
22%
793
55%
793
32%
1464
December1st to 15thNight
38%
975
22%
2730
12%
975
46%
975
29%
1749
December16th to endNight
33%
1040
23%
2803
12%
1040
41%
1040
26%
1870

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%2442445%7%44%
49193
Night
11%424423347%50%
49233
TransparencyDay
38%5%11%22%18%4
48894
Night
33%49%23%21%6%
49037
SeeingDay
12%6%20%26%24%9%
6176
Night
13%6%24%32%20%2
16347

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
18%6%23412335%46%
1746
16th to endDay
15%6%34412345%48%
1872
February1st to 15thDay
17%6%24323336%45%
1739
16th to endDay
18%6%35%6%23335%40%
1665
March1st to 15thDay
19%5%35%423345%41%
1980
16th to endDay
16%6%35%5%24446%40%
2114
April1st to 15thDay
12%6%24423346%48%
2151
16th to endDay
14%6%25%5%24446%42%
2160
May1st to 15thDay
15%6%35%5%25%5%5%6%39%
2178
16th to endDay
9%426%7%46%6%7%9%35%
2430
June1st to 15thDay
5%325%5%36%5%7%9%44%
2505
16th to endDay
5%3245%46%6%7%10%43%
2429
July1st to 15thDay
5%436%7%46%7%7%10%34%
2340
16th to endDay
5%3246%37%6%7%11%41%
2466
August1st to 15thDay
6%425%5%36%7%8%10%39%
2280
16th to endDay
8%426%5%35%6%8%9%37%
2292
September1st to 15thDay
12%5%24435%5%5%7%43%
2160
16th to endDay
11%32432445%5%52%
1979
October1st to 15thDay
13%42332335%6%51%
1800
16th to endDay
14%312212235%59%
1920
November1st to 15thDay
11%6%13313345%55%
1908
16th to endDay
15%6%1442333449%
1751
December1st to 15thDay
17%7%35%22325%5%44%
1560
16th to endDay
19%7%35%423345%40%
1768
January1st to 15thNight
18%6%2431223450%
2522
16th to endNight
16%5%1342333451%
2704
February1st to 15thNight
18%6%24323325%46%
2442
16th to endNight
16%433422335%50%
1965
March1st to 15thNight
17%6%35%314245%44%
1980
16th to endNight
14%5%25%423446%45%
2106
April1st to 15thNight
10%32342345%8%50%
1797
16th to endNight
9%424423348%50%
1800
May1st to 15thNight
13%5%2342445%7%45%
1769
16th to endNight
9%425%425%45%8%46%
1683
June1st to 15thNight
22133245%6%9%58%
1449
16th to endNight
332332446%9%57%
1525
July1st to 15thNight
33245%46%5%7%12%44%
1620
16th to endNight
32123346%7%12%51%
1702
August1st to 15thNight
32135%245%6%12%52%
1680
16th to endNight
5%415%436%6%7%10%44%
1910
September1st to 15thNight
9%5%2332445%7%52%
1800
16th to endNight
6%315%42335%7%55%
1967
October1st to 15thNight
9%325%323236%56%
2160
16th to endNight
12%21322232363%
2304
November1st to 15thNight
11%314322347%53%
2280
16th to endNight
14%5%2332332453%
2535
December1st to 15thNight
17%6%2441334447%
2730
16th to endNight
18%7%34423345%43%
2803

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%37%24%19%5%
1747
16th to endDay
39%36%23%22%5%
1872
February1st to 15thDay
41%310%24%16%3
1741
16th to endDay
47%46%19%17%4
1665
March1st to 15thDay
45%39%17%17%6%
1980
16th to endDay
44%411%23%14%1
2116
April1st to 15thDay
36%5%10%23%18%5%
2151
16th to endDay
41%48%21%19%3
2160
May1st to 15thDay
44%7%10%15%18%3
2178
16th to endDay
40%8%15%22%11%1
2434
June1st to 15thDay
33%6%13%27%18%
2505
16th to endDay
31%7%13%25%18%3
2429
July1st to 15thDay
37%9%13%24%12%1
2201
16th to endDay
31%9%17%25%14%1
2311
August1st to 15thDay
34%8%15%23%14%2
2266
16th to endDay
38%8%15%20%13%3
2292
September1st to 15thDay
37%6%11%18%17%7%
2160
16th to endDay
32%48%22%24%6%
1979
October1st to 15thDay
33%410%20%23%8%
1800
16th to endDay
27%3423%29%11%
1920
November1st to 15thDay
31%38%24%24%7%
1908
16th to endDay
38%36%19%24%6%
1751
December1st to 15thDay
42%39%22%15%6%
1560
16th to endDay
45%310%19%16%4
1768
January1st to 15thNight
39%17%21%25%4
2522
16th to endNight
37%36%22%23%7%
2704
February1st to 15thNight
41%37%23%18%5%
2451
16th to endNight
37%28%24%19%7%
1965
March1st to 15thNight
42%310%16%19%8%
1980
16th to endNight
41%48%24%19%2
2106
April1st to 15thNight
31%5%10%23%21%8%
1797
16th to endNight
32%5%11%23%23%4
1800
May1st to 15thNight
37%5%10%20%18%6%
1770
16th to endNight
34%7%14%24%16%1
1685
June1st to 15thNight
20%6%14%30%25%2
1449
16th to endNight
23%6%11%28%24%5%
1525
July1st to 15thNight
28%9%17%27%15%2
1530
16th to endNight
22%10%14%30%18%3
1594
August1st to 15thNight
23%7%17%30%17%2
1670
16th to endNight
31%8%13%25%17%3
1910
September1st to 15thNight
30%6%10%24%20%8%
1800
16th to endNight
27%5%9%21%26%9%
1967
October1st to 15thNight
30%38%22%23%11%
2160
16th to endNight
26%2419%34%12%
2304
November1st to 15thNight
31%37%23%24%11%
2280
16th to endNight
35%35%18%29%7%
2535
December1st to 15thNight
41%38%21%19%6%
2730
16th to endNight
43%38%21%18%4
2803

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
27%11%33%22%5%
135
16th to endDay
16%27%31%15%7%
144
February1st to 15thDay
19%19%40%17%3
135
16th to endDay
21%25%36%13%32
100
March1st to 15thDay
28%17%41%8%3
90
16th to endDay
11%26%22%32%9%
100
April1st to 15thDay
15%11%36%23%11%1
270
16th to endDay
21%7%26%25%15%3
270
May1st to 15thDay
16%8%29%27%14%3
315
16th to endDay
10%6%24%29%22%6%
517
June1st to 15thDay
7%212%34%31%12%
495
16th to endDay
5%216%34%27%12%
495
July1st to 15thDay
5%215%33%30%11%
475
16th to endDay
4425%40%24%
515
August1st to 15thDay
9%7%27%37%17%
433
16th to endDay
16%1421%38%18%
332
September1st to 15thDay
10%28%23%40%14%
315
16th to endDay
8%16%27%35%12%
212
October1st to 15thDay
11%427%31%20%5%
135
16th to endDay
15%6%31%29%12%3
144
November1st to 15thDay
20%7%25%25%18%2
135
16th to endDay
20%15%27%23%10%2
135
December1st to 15thDay
17%13%38%16%11%2
135
16th to endDay
23%20%38%13%4
144
January1st to 15thNight
22%9%31%28%7%
975
16th to endNight
17%10%37%30%4
1040
February1st to 15thNight
21%10%35%27%5%
922
16th to endNight
18%12%38%25%3
647
March1st to 15thNight
17%10%35%30%5%
540
16th to endNight
17%9%32%31%9%
576
April1st to 15thNight
11%10%38%26%10%
539
16th to endNight
11%8%35%31%12%
540
May1st to 15thNight
13%5%26%40%13%
540
16th to endNight
11%223%33%25%3
563
June1st to 15thNight
2112%42%36%4
540
16th to endNight
4110%41%35%5%
540
July1st to 15thNight
211%34%45%5%
510
16th to endNight
4428%52%10%
564
August1st to 15thNight
45%30%48%10%
539
16th to endNight
7%1433%47%6%
573
September1st to 15thNight
11%18%29%42%6%
540
16th to endNight
7%114%33%37%5%
603
October1st to 15thNight
11%219%33%29%3
720
16th to endNight
13%426%33%20%1
768
November1st to 15thNight
12%8%23%34%19%1
760
16th to endNight
17%7%27%32%15%
793
December1st to 15thNight
20%6%29%34%8%
975
16th to endNight
22%9%30%30%6%
1040
Page generated at 2018-02-23 10:21:29. Version ac04

Copyright 2018 A. Danko


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