Fayetteville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fayetteville clear sky chart from 2005-11-05 to 2017-08-12.

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%
15847
22%
46503
14%
15809
56%
15809
28%
29422

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%
717
22%
2327
13%
716
47%
716
23%
1444
January16th to endNight
31%
768
23%
2496
12%
768
46%
768
26%
1535
February1st to 15thNight
32%
702
21%
2287
11%
701
45%
701
26%
1390
February16th to endNight
30%
631
28%
1831
13%
631
46%
631
31%
1096
March1st to 15thNight
34%
720
26%
1980
14%
720
45%
720
32%
1219
March16th to endNight
40%
768
21%
2112
13%
768
48%
768
29%
1368
April1st to 15thNight
39%
718
23%
1846
11%
718
46%
718
33%
1172
April16th to endNight
48%
720
22%
1800
10%
720
52%
720
35%
1164
May1st to 15thNight
48%
585
17%
1665
9%
585
53%
585
28%
1073
May16th to endNight
64%
561
17%
1682
14%
561
65%
561
30%
1069
June1st to 15thNight
64%
540
14%
1620
12%
540
65%
540
27%
1055
June16th to endNight
67%
540
15%
1620
13%
540
68%
540
27%
1062
July1st to 15thNight
67%
510
12%
1530
10%
510
68%
510
25%
1032
July16th to endNight
72%
564
13%
1595
11%
531
73%
531
28%
1032
August1st to 15thNight
68%
527
15%
1575
13%
524
68%
524
25%
1063
August16th to endNight
64%
687
15%
1737
11%
687
65%
687
25%
1244
September1st to 15thNight
68%
660
25%
1672
20%
660
69%
660
32%
1099
September16th to endNight
48%
657
15%
1837
12%
657
51%
657
21%
1310
October1st to 15thNight
52%
660
27%
1980
25%
660
59%
660
30%
1233
October16th to endNight
52%
704
33%
2112
25%
704
65%
704
38%
1182
November1st to 15thNight
50%
700
29%
2101
21%
700
61%
700
35%
1192
November16th to endNight
46%
720
26%
2262
18%
720
57%
720
30%
1328
December1st to 15thNight
43%
720
22%
2340
16%
720
52%
720
25%
1458
December16th to endNight
39%
768
23%
2496
17%
768
48%
768
23%
1602

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%2445%7%43%
47465
Night
12%5%2442445%7%44%
46702
TransparencyDay
38%6%12%19%17%4
47166
Night
37%6%11%18%18%6%
46505
SeeingDay
15%5%18%24%23%12%
5668
Night
15%5%23%33%19%2
15854

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%5%3432343444%
1611
16th to endDay
15%6%24423345%47%
1728
February1st to 15thDay
17%5%1441345%5%45%
1575
16th to endDay
16%5%14423346%47%
1638
March1st to 15thDay
12%41342445%7%48%
1980
16th to endDay
15%5%24424347%44%
2111
April1st to 15thDay
10%31232435%8%53%
2101
16th to endDay
11%5%2443445%7%47%
2160
May1st to 15thDay
11%5%26%6%35%46%7%39%
2295
16th to endDay
7%425%5%35%6%6%8%43%
2431
June1st to 15thDay
9%325%5%45%6%6%8%41%
2340
16th to endDay
7%325%6%37%6%6%11%39%
2340
July1st to 15thDay
8%5%25%6%47%7%8%10%33%
2340
16th to endDay
5%5%26%6%46%7%9%12%34%
2465
August1st to 15thDay
11%6%26%6%36%6%6%10%32%
2288
16th to endDay
11%6%26%6%5%5%6%8%10%29%
2102
September1st to 15thDay
9%3145%36%47%10%43%
1955
16th to endDay
19%7%27%6%3446%5%32%
1793
October1st to 15thDay
18%5%23423335%47%
1650
16th to endDay
10%424313235%58%
1760
November1st to 15thDay
15%423212336%54%
1757
16th to endDay
13%5%23313347%49%
1697
December1st to 15thDay
15%6%26%413446%43%
1620
16th to endDay
19%6%24413335%43%
1728
January1st to 15thNight
14%5%25%42435%6%45%
2327
16th to endNight
16%5%2432335%6%45%
2496
February1st to 15thNight
17%413424335%48%
2278
16th to endNight
12%4233345%5%6%48%
1831
March1st to 15thNight
13%41432435%6%49%
1980
16th to endNight
14%425%3245%6%5%44%
2112
April1st to 15thNight
11%5%24424347%48%
1846
16th to endNight
11%324425%5%5%7%47%
1800
May1st to 15thNight
8%6%27%43445%9%42%
1664
16th to endNight
9%5%246%35%5%5%8%44%
1682
June1st to 15thNight
10%5%235%46%6%6%10%37%
1620
16th to endNight
5%5%35%5%36%5%8%10%39%
1620
July1st to 15thNight
6%426%6%36%7%9%11%32%
1620
16th to endNight
6%425%5%46%7%6%11%38%
1703
August1st to 15thNight
8%6%26%6%26%5%7%10%37%
1586
16th to endNight
9%5%26%7%36%7%7%9%32%
1737
September1st to 15thNight
9%5%35%4245%6%8%43%
1672
16th to endNight
20%6%26%6%34347%34%
1837
October1st to 15thNight
18%5%24323235%49%
1980
16th to endNight
10%424312246%57%
2112
November1st to 15thNight
13%414313235%55%
2101
16th to endNight
14%5%13414245%51%
2262
December1st to 15thNight
15%6%25%42435%6%43%
2340
16th to endNight
18%7%24424346%42%
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
42%5%8%16%20%6%
1612
16th to endDay
39%45%18%23%8%
1728
February1st to 15thDay
39%29%19%23%5%
1577
16th to endDay
38%38%22%21%5%
1638
March1st to 15thDay
35%411%22%20%6%
1980
16th to endDay
39%6%10%19%19%3
2112
April1st to 15thDay
29%312%25%21%6%
2101
16th to endDay
35%6%11%19%18%7%
2160
May1st to 15thDay
41%8%13%20%14%2
2295
16th to endDay
36%8%16%21%15%
2435
June1st to 15thDay
37%9%16%21%14%
2340
16th to endDay
36%9%18%21%11%3
2340
July1st to 15thDay
38%12%18%18%8%2
2201
16th to endDay
35%13%20%20%8%2
2310
August1st to 15thDay
44%9%16%17%11%
2275
16th to endDay
46%10%15%17%9%1
2102
September1st to 15thDay
34%9%15%16%17%5%
1955
16th to endDay
51%6%9%12%16%3
1793
October1st to 15thDay
39%49%22%20%3
1650
16th to endDay
30%38%20%29%8%
1760
November1st to 15thDay
32%38%19%27%8%
1757
16th to endDay
34%48%21%22%8%
1697
December1st to 15thDay
41%411%18%18%5%
1620
16th to endDay
44%47%19%18%5%
1728
January1st to 15thNight
40%5%9%14%24%6%
2327
16th to endNight
40%36%19%21%8%
2496
February1st to 15thNight
38%48%17%23%7%
2287
16th to endNight
34%410%20%23%6%
1831
March1st to 15thNight
33%5%9%20%23%7%
1980
16th to endNight
37%6%11%18%20%5%
2112
April1st to 15thNight
35%5%9%20%22%6%
1846
16th to endNight
35%6%11%19%18%9%
1800
May1st to 15thNight
37%7%14%20%16%2
1665
16th to endNight
35%8%14%26%13%1
1684
June1st to 15thNight
38%8%19%20%10%1
1620
16th to endNight
35%11%17%20%12%2
1620
July1st to 15thNight
38%11%17%21%8%2
1530
16th to endNight
35%11%21%19%11%1
1595
August1st to 15thNight
40%9%18%20%9%1
1575
16th to endNight
42%10%17%18%9%1
1737
September1st to 15thNight
35%8%16%18%14%6%
1672
16th to endNight
49%5%11%14%15%3
1837
October1st to 15thNight
38%48%18%23%6%
1980
16th to endNight
29%47%20%26%12%
2112
November1st to 15thNight
32%37%15%27%14%
2101
16th to endNight
35%47%17%25%10%
2262
December1st to 15thNight
39%5%11%18%18%6%
2340
16th to endNight
44%48%17%19%6%
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
17%14%30%30%7%
90
16th to endDay
20%19%36%18%4
96
February1st to 15thDay
22%16%42%16%2
90
16th to endDay
14%9%38%26%9%
195
March1st to 15thDay
14%10%31%30%12%
270
16th to endDay
17%7%29%28%14%2
288
April1st to 15thDay
15%14%23%21%18%5%
270
16th to endDay
16%322%28%23%5%
270
May1st to 15thDay
14%7%27%27%15%7%
288
16th to endDay
11%214%21%26%23%
331
June1st to 15thDay
12%113%22%32%17%
315
16th to endDay
9%112%20%35%20%
315
July1st to 15thDay
7%5%24%41%19%
305
16th to endDay
7%6%23%41%19%
326
August1st to 15thDay
16%17%19%29%24%
297
16th to endDay
13%1420%26%33%
268
September1st to 15thDay
9%28%23%27%28%
255
16th to endDay
29%214%20%22%9%
254
October1st to 15thDay
27%318%20%22%7%
255
16th to endDay
12%419%29%25%8%
272
November1st to 15thDay
17%7%23%26%18%6%
265
16th to endDay
16%5%20%32%22%1
167
December1st to 15thDay
22%6%36%21%12%1
90
16th to endDay
26%15%33%14%9%1
96
January1st to 15thNight
16%10%30%32%9%
720
16th to endNight
18%8%37%30%4
768
February1st to 15thNight
19%10%35%31%2
704
16th to endNight
14%10%40%30%3
631
March1st to 15thNight
15%9%37%29%7%
720
16th to endNight
17%7%29%35%9%
768
April1st to 15thNight
14%9%32%33%10%
718
16th to endNight
13%5%28%39%12%
720
May1st to 15thNight
11%5%27%39%14%
585
16th to endNight
11%14%37%33%1
563
June1st to 15thNight
12%211%39%28%5%
540
16th to endNight
7%111%41%32%6%
540
July1st to 15thNight
9%10%36%38%4
510
16th to endNight
7%17%37%41%4
564
August1st to 15thNight
13%7%32%40%4
527
16th to endNight
12%7%31%40%6%
687
September1st to 15thNight
12%6%32%41%5%
660
16th to endNight
22%215%28%28%2
657
October1st to 15thNight
22%218%26%26%2
660
16th to endNight
12%426%30%22%3
704
November1st to 15thNight
15%422%36%18%2
700
16th to endNight
16%7%25%31%18%
720
December1st to 15thNight
17%7%24%38%11%
720
16th to endNight
22%8%24%36%8%
768
Page generated at 2017-08-13 14:17:00. Version ac04

Copyright 2017 A. Danko


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