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

2017-09-12
.

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
34%
15782
22%
46837
12%
15735
44%
15735
26%
29378

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%
900
21%
2434
5%
895
28%
895
19%
1640
January16th to endNight
15%
960
22%
2496
5%
960
27%
960
22%
1701
February1st to 15thNight
15%
841
17%
2249
4%
838
24%
838
19%
1547
February16th to endNight
16%
631
21%
1893
5%
631
29%
631
20%
1223
March1st to 15thNight
17%
624
18%
2064
7%
624
27%
624
17%
1388
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%
530
26%
1767
25%
530
66%
530
29%
1038
September16th to endNight
55%
592
29%
1772
21%
592
63%
592
33%
1029
October1st to 15thNight
45%
660
30%
1980
20%
660
54%
660
35%
1123
October16th to endNight
30%
704
27%
2112
13%
704
44%
704
30%
1244
November1st to 15thNight
31%
700
29%
2251
15%
700
47%
700
31%
1247
November16th to endNight
22%
756
23%
2376
12%
756
35%
756
21%
1503
December1st to 15thNight
19%
900
18%
2520
5%
900
30%
900
20%
1746
December16th to endNight
15%
960
18%
2688
4%
960
28%
960
18%
1905

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%35%45%7%41%
47820
Night
12%6%25%424346%46%
47024
TransparencyDay
41%6%12%22%14%2
47510
Night
38%5%11%24%17%3
46839
SeeingDay
15%10%27%25%16%4
5809
Night
16%13%31%24%12%1
15782

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%25%424335%43%
1501
16th to endDay
11%8%35%6%23347%42%
1728
February1st to 15thDay
13%8%48%42445%5%37%
1612
16th to endDay
11%10%26%435%45%7%37%
1580
March1st to 15thDay
15%8%45%5%24346%38%
1905
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%
2112
16th to endDay
11%5%2442445%6%46%
1843
October1st to 15thDay
12%6%24423436%50%
1650
16th to endDay
13%5%23322345%54%
1760
November1st to 15thDay
11%6%34323345%52%
1607
16th to endDay
16%8%25%424345%42%
1581
December1st to 15thDay
17%9%36%6%35%336%36%
1440
16th to endDay
14%11%47%42445%5%35%
1536
January1st to 15thNight
13%7%35%5%34445%42%
2434
16th to endNight
11%7%46%5%34345%42%
2496
February1st to 15thNight
14%8%47%42335%5%39%
2240
16th to endNight
12%7%47%5%23335%44%
1893
March1st to 15thNight
15%10%35%5%2333440%
2064
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%
1767
16th to endNight
9%5%2341335%7%52%
1772
October1st to 15thNight
10%314424336%55%
1980
16th to endNight
16%5%1422223453%
2112
November1st to 15thNight
9%5%23423336%55%
2251
16th to endNight
17%8%24322335%45%
2376
December1st to 15thNight
18%8%35%42435%6%35%
2520
16th to endNight
16%10%46%424345%36%
2688

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
43%311%22%16%2
1502
16th to endDay
40%5%13%26%11%1
1728
February1st to 15thDay
47%5%12%22%11%1
1614
16th to endDay
45%5%12%23%11%2
1580
March1st to 15thDay
46%6%9%19%14%3
1905
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
35%7%11%23%18%3
2112
16th to endDay
36%6%7%26%19%2
1843
October1st to 15thDay
35%5%9%24%21%3
1650
16th to endDay
33%39%28%21%4
1760
November1st to 15thDay
34%310%24%18%8%
1607
16th to endDay
44%39%23%16%1
1581
December1st to 15thDay
50%49%20%13%1
1440
16th to endDay
49%5%10%19%12%1
1536
January1st to 15thNight
42%6%9%23%16%2
2434
16th to endNight
43%411%23%15%1
2496
February1st to 15thNight
45%5%10%23%13%2
2249
16th to endNight
43%412%23%15%1
1893
March1st to 15thNight
47%48%19%16%2
2064
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%6%24%21%5%
1767
16th to endNight
31%5%8%25%25%3
1772
October1st to 15thNight
31%49%25%24%5%
1980
16th to endNight
35%29%26%20%5%
2112
November1st to 15thNight
30%410%25%21%7%
2251
16th to endNight
42%37%24%20%1
2376
December1st to 15thNight
47%5%12%19%14%1
2520
16th to endNight
49%5%11%18%12%3
2688

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
34%23%37%4
90
16th to endDay
22%33%36%5%2
96
February1st to 15thDay
22%28%36%12%
90
16th to endDay
27%23%35%12%1
81
March1st to 15thDay
28%24%38%6%1
90
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
12%5%16%28%28%9%
299
16th to endDay
13%7%20%22%26%9%
229
October1st to 15thDay
12%13%40%24%7%2
90
16th to endDay
15%12%35%31%41
96
November1st to 15thDay
10%7%38%27%10%5%
90
16th to endDay
41%18%22%13%4
90
December1st to 15thDay
22%22%34%14%24
90
16th to endDay
27%29%36%6%1
96
January1st to 15thNight
21%26%34%13%3
900
16th to endNight
16%25%39%15%2
960
February1st to 15thNight
21%22%38%16%1
841
16th to endNight
19%23%39%16%1
631
March1st to 15thNight
25%18%37%16%2
624
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%31%4
530
16th to endNight
12%5%20%27%28%5%
592
October1st to 15thNight
12%6%30%26%19%3
660
16th to endNight
20%12%34%22%8%
704
November1st to 15thNight
12%14%37%25%9%1
700
16th to endNight
24%20%31%19%4
756
December1st to 15thNight
26%17%35%17%3
900
16th to endNight
23%20%38%16%1
960
Page generated at 2017-09-13 06:39:10. Version ac04

Copyright 2017 A. Danko


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