Council Bluffs Recreational Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Council Bluffs Recreational Area 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
34%
16566
22%
49115
12%
16519
44%
16519
26%
30831

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
15%
975
20%
2638
4%
970
27%
970
19%
1789
January16th to endNight
16%
1040
22%
2704
5%
1040
28%
1040
23%
1820
February1st to 15thNight
15%
912
16%
2440
3%
909
23%
909
19%
1688
February16th to endNight
15%
683
20%
2049
5%
683
28%
683
19%
1347
March1st to 15thNight
17%
664
18%
2192
7%
664
27%
664
17%
1473
March16th to endNight
21%
576
14%
2052
7%
576
32%
576
17%
1379
April1st to 15thNight
24%
539
21%
1797
10%
539
40%
539
25%
1055
April16th to endNight
30%
540
20%
1800
11%
540
43%
540
24%
1130
May1st to 15thNight
34%
540
17%
1711
11%
539
44%
539
25%
1087
May16th to endNight
41%
563
19%
1497
12%
561
46%
561
25%
1047
June1st to 15thNight
59%
540
21%
1440
14%
540
64%
540
41%
845
June16th to endNight
57%
540
24%
1440
14%
540
64%
540
43%
834
July1st to 15thNight
66%
510
18%
1360
14%
510
68%
510
40%
818
July16th to endNight
72%
564
22%
1555
19%
531
76%
531
39%
895
August1st to 15thNight
73%
539
22%
1673
25%
536
75%
536
39%
909
August16th to endNight
68%
573
24%
1910
27%
573
71%
573
36%
1045
September1st to 15thNight
60%
540
26%
1800
25%
540
66%
540
29%
1054
September16th to endNight
57%
646
31%
1933
23%
646
64%
646
34%
1111
October1st to 15thNight
44%
720
28%
2160
19%
720
53%
720
34%
1238
October16th to endNight
30%
768
29%
2304
14%
768
45%
768
31%
1344
November1st to 15thNight
30%
760
28%
2444
15%
760
45%
760
29%
1393
November16th to endNight
23%
819
25%
2574
13%
819
37%
819
22%
1601
December1st to 15thNight
20%
975
18%
2730
6%
975
32%
975
21%
1854
December16th to endNight
15%
1040
18%
2912
4%
1040
27%
1040
17%
2075

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%6%25%5%3445%7%41%
49511
Night
12%6%25%424346%46%
49302
TransparencyDay
41%6%11%22%15%2
49201
Night
38%5%11%23%17%3
49117
SeeingDay
16%10%27%25%15%4
6367
Night
16%13%31%24%12%1
16566

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
14%8%36%434335%42%
1627
16th to endDay
10%7%35%5%23347%44%
1872
February1st to 15thDay
14%8%48%42445%5%37%
1751
16th to endDay
14%10%26%335%45%6%36%
1710
March1st to 15thDay
15%8%45%5%24346%38%
2014
16th to endDay
17%11%35%6%34446%31%
2169
April1st to 15thDay
12%7%245%3335%6%44%
2151
16th to endDay
19%7%35%5%2345%6%35%
2160
May1st to 15thDay
17%6%345%35%46%8%36%
2236
16th to endDay
12%7%26%5%35%5%46%38%
2617
June1st to 15thDay
7%425%5%35%5%6%8%43%
2520
16th to endDay
6%3235%35%5%7%10%46%
2520
July1st to 15thDay
10%425%5%36%6%6%9%40%
2520
16th to endDay
44145%48%6%7%10%40%
2503
August1st to 15thDay
8%5%25%5%46%6%7%9%39%
2277
16th to endDay
8%5%25%5%35%6%6%8%40%
2292
September1st to 15thDay
13%42433446%8%44%
2160
16th to endDay
11%5%3442445%7%46%
2011
October1st to 15thDay
12%6%24433436%48%
1800
16th to endDay
12%5%23423345%53%
1920
November1st to 15thDay
11%6%34323345%51%
1744
16th to endDay
15%8%25%424345%44%
1713
December1st to 15thDay
15%8%36%6%35%336%37%
1560
16th to endDay
14%11%46%43445%5%35%
1664
January1st to 15thNight
13%7%36%6%34445%41%
2638
16th to endNight
10%8%46%5%34345%43%
2704
February1st to 15thNight
14%8%47%5%2335%6%38%
2431
16th to endNight
14%7%46%5%23235%42%
2049
March1st to 15thNight
16%10%35%5%2333440%
2192
16th to endNight
18%8%36%433445%36%
2052
April1st to 15thNight
10%5%24423447%48%
1797
16th to endNight
15%6%245%24346%44%
1800
May1st to 15thNight
16%42332445%7%44%
1711
16th to endNight
10%7%25%6%35%45%7%41%
1496
June1st to 15thNight
7%314325%5%5%10%51%
1440
16th to endNight
5%31333446%10%53%
1440
July1st to 15thNight
8%313333449%53%
1440
16th to endNight
43243245%6%10%51%
1662
August1st to 15thNight
5%3133235%7%10%53%
1683
16th to endNight
5%32443446%8%52%
1910
September1st to 15thNight
10%5%2443335%6%49%
1800
16th to endNight
8%5%1342335%7%53%
1933
October1st to 15thNight
10%324424336%54%
2160
16th to endNight
15%41422223454%
2304
November1st to 15thNight
11%5%23423337%52%
2444
16th to endNight
16%8%24323335%47%
2574
December1st to 15thNight
17%8%3442435%6%38%
2730
16th to endNight
15%11%46%5%24346%35%
2912

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
44%310%22%15%3
1628
16th to endDay
38%5%14%26%13%2
1872
February1st to 15thDay
46%5%12%22%11%1
1753
16th to endDay
47%411%21%11%3
1710
March1st to 15thDay
46%5%9%19%14%4
2014
16th to endDay
53%6%12%18%8%
2171
April1st to 15thDay
39%411%22%19%2
2151
16th to endDay
49%5%10%20%12%1
2160
May1st to 15thDay
46%6%11%22%12%
2236
16th to endDay
45%8%12%18%13%2
2621
June1st to 15thDay
36%8%13%24%16%1
2520
16th to endDay
29%8%17%24%16%3
2520
July1st to 15thDay
38%7%12%24%12%4
2371
16th to endDay
34%9%17%24%12%1
2347
August1st to 15thDay
37%9%13%24%14%1
2263
16th to endDay
37%7%14%20%14%5%
2292
September1st to 15thDay
36%6%10%23%18%3
2160
16th to endDay
35%6%8%27%19%2
2011
October1st to 15thDay
37%5%9%23%20%3
1800
16th to endDay
33%29%28%21%4
1920
November1st to 15thDay
36%39%24%17%7%
1744
16th to endDay
43%39%24%18%1
1713
December1st to 15thDay
48%5%9%21%13%1
1560
16th to endDay
50%5%11%18%12%1
1664
January1st to 15thNight
43%5%9%22%15%2
2638
16th to endNight
42%411%23%16%1
2704
February1st to 15thNight
46%5%10%21%13%2
2440
16th to endNight
45%411%21%15%1
2049
March1st to 15thNight
47%48%18%15%4
2192
16th to endNight
48%5%12%22%10%
2052
April1st to 15thNight
35%5%12%26%17%3
1797
16th to endNight
40%410%26%15%2
1800
May1st to 15thNight
39%7%15%20%16%1
1712
16th to endNight
42%9%11%20%14%3
1498
June1st to 15thNight
27%6%15%29%19%1
1440
16th to endNight
23%8%14%28%19%4
1440
July1st to 15thNight
29%6%15%27%15%4
1360
16th to endNight
26%8%16%30%16%1
1555
August1st to 15thNight
23%9%17%27%20%2
1673
16th to endNight
27%7%16%23%20%5%
1910
September1st to 15thNight
35%5%7%25%21%5%
1800
16th to endNight
30%6%8%26%24%3
1933
October1st to 15thNight
32%410%24%23%5%
2160
16th to endNight
34%38%26%21%5%
2304
November1st to 15thNight
33%410%24%20%6%
2444
16th to endNight
41%37%24%21%1
2574
December1st to 15thNight
45%5%11%20%15%1
2730
16th to endNight
49%5%11%18%11%3
2912

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
30%22%38%7%1
135
16th to endDay
20%31%36%10%1
144
February1st to 15thDay
24%27%37%9%
135
16th to endDay
34%23%30%10%1
120
March1st to 15thDay
30%21%40%6%
121
16th to endDay
27%23%36%10%1
155
April1st to 15thDay
20%15%37%20%5%
270
16th to endDay
24%17%32%14%7%2
270
May1st to 15thDay
18%17%34%19%7%2
328
16th to endDay
17%11%35%22%10%3
517
June1st to 15thDay
10%5%27%32%17%5%
495
16th to endDay
8%5%31%36%14%3
495
July1st to 15thDay
14%221%35%21%5%
475
16th to endDay
6%214%33%34%8%
515
August1st to 15thDay
13%112%33%30%9%
430
16th to endDay
12%217%30%27%10%
332
September1st to 15thDay
13%5%15%27%28%9%
315
16th to endDay
11%6%19%26%26%9%
287
October1st to 15thDay
16%12%36%27%5%1
135
16th to endDay
13%19%34%29%2
144
November1st to 15thDay
16%10%37%25%6%3
135
16th to endDay
31%16%33%14%4
135
December1st to 15thDay
20%26%34%12%24
135
16th to endDay
27%29%36%5%
144
January1st to 15thNight
21%26%34%14%3
975
16th to endNight
16%24%39%16%2
1040
February1st to 15thNight
21%22%38%15%1
912
16th to endNight
21%22%37%16%1
683
March1st to 15thNight
25%18%37%16%2
664
16th to endNight
20%16%37%20%5%
576
April1st to 15thNight
15%18%39%22%4
539
16th to endNight
19%11%36%25%6%
540
May1st to 15thNight
19%7%35%26%10%
540
16th to endNight
13%7%31%31%13%2
563
June1st to 15thNight
10%223%37%24%2
540
16th to endNight
6%228%39%21%2
540
July1st to 15thNight
11%15%40%27%4
510
16th to endNight
5%111%43%31%5%
564
August1st to 15thNight
6%212%34%41%4
539
16th to endNight
6%16%35%33%6%
573
September1st to 15thNight
12%216%31%32%4
540
16th to endNight
11%5%19%28%28%5%
646
October1st to 15thNight
12%6%31%27%18%3
720
16th to endNight
19%12%35%23%8%
768
November1st to 15thNight
14%14%37%24%8%1
760
16th to endNight
23%19%31%20%5%
819
December1st to 15thNight
24%17%35%18%3
975
16th to endNight
23%20%38%16%1
1040
Page generated at 2018-03-12 12:28:15. Version ac04

Copyright 2018 A. Danko


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