Omaha
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Omaha 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
34%
15882
21%
46595
10%
15836
43%
15836
26%
28582

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
29%
900
19%
2327
9%
895
36%
895
24%
1532
January16th to endNight
23%
960
23%
2496
7%
960
34%
960
21%
1680
February1st to 15thNight
22%
880
12%
2288
4%
876
27%
876
19%
1643
February16th to endNight
25%
690
23%
1952
6%
690
39%
690
26%
1209
March1st to 15thNight
29%
554
22%
1994
12%
554
41%
554
21%
1171
March16th to endNight
23%
576
15%
2112
8%
576
33%
576
15%
1367
April1st to 15thNight
24%
539
20%
1872
11%
539
40%
539
20%
1131
April16th to endNight
25%
540
20%
1620
9%
540
40%
540
18%
1070
May1st to 15thNight
29%
540
17%
1620
9%
540
40%
540
22%
1041
May16th to endNight
32%
562
16%
1613
6%
561
41%
561
22%
1042
June1st to 15thNight
42%
540
17%
1440
5%
540
48%
540
31%
880
June16th to endNight
45%
540
22%
1440
7%
540
53%
540
41%
792
July1st to 15thNight
56%
510
17%
1481
9%
510
60%
510
40%
786
July16th to endNight
61%
564
25%
1594
18%
531
71%
531
47%
779
August1st to 15thNight
62%
527
20%
1575
20%
524
66%
524
35%
891
August16th to endNight
53%
525
23%
1605
20%
525
61%
525
33%
915
September1st to 15thNight
47%
495
25%
1735
20%
495
59%
495
30%
933
September16th to endNight
48%
492
28%
1815
22%
492
60%
492
34%
904
October1st to 15thNight
34%
630
27%
1950
15%
630
44%
630
29%
1147
October16th to endNight
36%
704
24%
2112
12%
704
46%
704
31%
1224
November1st to 15thNight
33%
854
28%
2254
11%
854
45%
854
34%
1302
November16th to endNight
26%
900
23%
2512
8%
900
38%
900
27%
1543
December1st to 15thNight
23%
900
15%
2520
5%
900
31%
900
19%
1726
December16th to endNight
24%
960
19%
2668
6%
960
35%
960
18%
1874

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
11%6%25%42445%7%43%
47359
Night
10%6%24423447%48%
46786
Cloud CoverDay
11%6%35%5%2445%7%43%
47370
Night
10%6%24423447%48%
46790
Cloud CoverDay
11%6%25%42445%7%43%
47368
Night
10%6%24424347%48%
46790
TransparencyDay
40%6%14%24%13%1
47068
Night
35%5%13%26%16%2
46595
SeeingDay
12%15%28%26%13%2
5849
Night
12%22%27%27%9%
15883

By Month

Percentage Cloud Cover NE (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
8%8%35%7%35%447%41%
1611
16th to endDay
10%11%37%5%2445%7%35%
1728
February1st to 15thDay
11%9%5%9%5%35%45%6%33%
1575
16th to endDay
11%8%37%6%33447%38%
1530
March1st to 15thDay
10%9%46%5%3445%5%41%
1954
16th to endDay
17%10%35%425%446%33%
2112
April1st to 15thDay
16%8%26%5%23335%40%
2075
16th to endDay
22%8%25%424446%34%
2340
May1st to 15thDay
14%6%35%6%25%45%7%39%
2331
16th to endDay
14%6%45%5%35%5%5%8%36%
2499
June1st to 15thDay
10%5%25%5%3446%8%43%
2520
16th to endDay
6%314425%5%6%8%50%
2520
July1st to 15thDay
7%4244245%6%9%48%
2385
16th to endDay
421443446%10%52%
2466
August1st to 15thDay
6%425%5%35%6%7%10%42%
2289
16th to endDay
9%415%4245%6%9%46%
2245
September1st to 15thDay
12%5%2442345%6%49%
1893
16th to endDay
10%414323345%56%
1815
October1st to 15thDay
13%5%23323345%51%
1669
16th to endDay
13%6%25%42334449%
1760
November1st to 15thDay
8%5%14324335%57%
1602
16th to endDay
13%8%45%414347%42%
1446
December1st to 15thDay
12%11%38%434446%34%
1440
16th to endDay
13%10%5%8%6%34445%32%
1554
January1st to 15thNight
7%6%35%6%3446%7%43%
2327
16th to endNight
10%9%46%5%13336%44%
2496
February1st to 15thNight
12%8%5%8%6%3345%6%36%
2285
16th to endNight
8%5%35%42445%6%48%
1952
March1st to 15thNight
10%8%24423346%49%
1982
16th to endNight
16%8%25%42335%8%37%
2112
April1st to 15thNight
12%7%35%323446%46%
1872
16th to endNight
16%8%25%323445%42%
1620
May1st to 15thNight
13%5%36%42436%6%43%
1620
16th to endNight
12%5%3442345%8%44%
1611
June1st to 15thNight
8%3244245%6%7%50%
1440
16th to endNight
32133245%6%9%58%
1440
July1st to 15thNight
321332446%10%56%
1571
16th to endNight
3112323449%62%
1702
August1st to 15thNight
5%2244245%6%8%53%
1585
16th to endNight
10%324423236%54%
1605
September1st to 15thNight
10%413413346%54%
1735
16th to endNight
8%423213346%59%
1815
October1st to 15thNight
14%423322335%52%
1950
16th to endNight
12%5%14322345%53%
2112
November1st to 15thNight
8%323323347%57%
2254
16th to endNight
11%6%33323346%51%
2512
December1st to 15thNight
13%9%36%5%34446%40%
2520
16th to endNight
13%10%36%5%24347%37%
2668

Percentage Cloud Cover SW (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
8%7%35%7%35%446%41%
1611
16th to endDay
10%12%37%5%3435%8%35%
1728
February1st to 15thDay
10%9%5%9%5%35%45%6%33%
1575
16th to endDay
11%8%47%6%33447%38%
1530
March1st to 15thDay
10%9%46%43445%5%41%
1965
16th to endDay
16%10%45%425%45%7%33%
2112
April1st to 15thDay
16%8%26%5%24336%40%
2075
16th to endDay
22%7%25%42445%6%34%
2340
May1st to 15thDay
13%6%35%6%25%45%7%38%
2331
16th to endDay
14%6%36%5%25%5%5%8%36%
2499
June1st to 15thDay
10%5%25%5%25%46%8%43%
2520
16th to endDay
6%314425%5%6%7%51%
2520
July1st to 15thDay
7%4244245%6%8%48%
2385
16th to endDay
422442446%9%53%
2466
August1st to 15thDay
6%326%5%36%6%6%10%41%
2289
16th to endDay
9%415%4245%5%8%46%
2245
September1st to 15thDay
11%5%2442435%6%48%
1893
16th to endDay
10%324223345%56%
1815
October1st to 15thDay
13%5%23423346%51%
1669
16th to endDay
13%6%25%43334448%
1760
November1st to 15thDay
8%5%14313335%56%
1602
16th to endDay
13%9%45%423347%42%
1446
December1st to 15thDay
12%11%38%5%34446%35%
1440
16th to endDay
13%9%5%8%7%34445%32%
1554
January1st to 15thNight
7%7%36%6%3445%7%43%
2327
16th to endNight
11%8%46%424336%44%
2496
February1st to 15thNight
12%9%48%6%33446%36%
2278
16th to endNight
8%5%36%42346%6%48%
1952
March1st to 15thNight
10%8%34323345%49%
1994
16th to endNight
16%8%26%42435%8%36%
2112
April1st to 15thNight
12%7%25%32435%6%46%
1872
16th to endNight
16%8%34423445%42%
1620
May1st to 15thNight
12%6%35%42346%7%43%
1619
16th to endNight
11%6%35%42435%8%44%
1611
June1st to 15thNight
8%4244245%5%9%50%
1440
16th to endNight
323315%5%5%10%57%
1440
July1st to 15thNight
321342446%10%56%
1571
16th to endNight
2212323449%63%
1702
August1st to 15thNight
42144245%6%8%53%
1585
16th to endNight
10%324423336%55%
1605
September1st to 15thNight
10%412423447%54%
1735
16th to endNight
8%423213346%59%
1815
October1st to 15thNight
14%5%13322345%52%
1950
16th to endNight
12%5%14322435%53%
2112
November1st to 15thNight
8%423313347%56%
2254
16th to endNight
11%6%24323346%51%
2512
December1st to 15thNight
13%9%36%5%34346%39%
2520
16th to endNight
13%10%47%5%23347%37%
2668

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
8%7%35%7%45%446%41%
1611
16th to endDay
10%12%37%5%2445%7%35%
1728
February1st to 15thDay
10%9%5%8%6%35%45%7%33%
1575
16th to endDay
11%8%47%6%3345%7%38%
1530
March1st to 15thDay
10%9%46%43445%5%40%
1965
16th to endDay
17%10%35%434446%34%
2110
April1st to 15thDay
16%7%26%5%24345%40%
2075
16th to endDay
22%7%24424445%34%
2340
May1st to 15thDay
13%6%36%5%2445%7%38%
2331
16th to endDay
14%5%36%5%35%45%8%36%
2499
June1st to 15thDay
10%5%25%4345%6%8%43%
2520
16th to endDay
6%314425%5%6%8%50%
2520
July1st to 15thDay
7%4244245%6%8%48%
2385
16th to endDay
42233345%6%9%53%
2466
August1st to 15thDay
6%425%6%36%6%6%9%42%
2289
16th to endDay
9%4244245%6%8%46%
2245
September1st to 15thDay
12%6%14424446%49%
1893
16th to endDay
10%41422335%5%56%
1815
October1st to 15thDay
13%5%23323336%51%
1669
16th to endDay
14%6%35%33334448%
1760
November1st to 15thDay
9%5%14313345%56%
1602
16th to endDay
13%8%35%424347%42%
1446
December1st to 15thDay
13%10%37%5%34446%35%
1440
16th to endDay
13%10%49%7%34445%32%
1554
January1st to 15thNight
7%6%35%6%3446%7%43%
2327
16th to endNight
10%9%46%424236%44%
2496
February1st to 15thNight
12%9%38%6%3345%6%36%
2278
16th to endNight
8%6%35%42345%6%48%
1952
March1st to 15thNight
10%8%34324346%49%
1994
16th to endNight
16%8%25%42436%7%37%
2112
April1st to 15thNight
12%7%24423446%46%
1872
16th to endNight
17%7%35%324345%42%
1620
May1st to 15thNight
13%5%26%42445%7%43%
1619
16th to endNight
11%6%25%42335%8%44%
1611
June1st to 15thNight
8%4144145%6%8%50%
1440
16th to endNight
3213225%5%5%10%58%
1440
July1st to 15thNight
32133245%6%10%56%
1571
16th to endNight
322313349%63%
1702
August1st to 15thNight
42244246%6%8%53%
1585
16th to endNight
10%424424336%55%
1605
September1st to 15thNight
11%313423346%54%
1735
16th to endNight
9%422213346%59%
1815
October1st to 15thNight
15%423323335%52%
1950
16th to endNight
12%5%13323345%53%
2112
November1st to 15thNight
8%423323347%57%
2254
16th to endNight
11%6%34323246%50%
2512
December1st to 15thNight
13%10%35%434446%39%
2520
16th to endNight
13%10%36%5%24346%37%
2668

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%6%17%22%10%
1612
16th to endDay
48%5%16%19%9%
1728
February1st to 15thDay
50%6%16%20%7%
1576
16th to endDay
44%7%12%21%12%1
1530
March1st to 15thDay
44%5%13%22%12%1
1965
16th to endDay
51%5%15%19%6%1
2112
April1st to 15thDay
46%5%10%26%9%1
2075
16th to endDay
50%6%11%20%9%
2340
May1st to 15thDay
44%6%12%22%12%
2331
16th to endDay
43%8%14%21%9%
2503
June1st to 15thDay
37%7%15%23%13%1
2520
16th to endDay
28%8%15%30%12%3
2520
July1st to 15thDay
32%8%15%26%13%3
2246
16th to endDay
24%7%18%29%18%2
2311
August1st to 15thDay
33%9%17%24%14%1
2275
16th to endDay
33%7%12%26%14%5%
2245
September1st to 15thDay
35%5%12%25%18%3
1893
16th to endDay
29%411%32%20%1
1815
October1st to 15thDay
34%411%26%21%2
1669
16th to endDay
38%412%24%17%2
1760
November1st to 15thDay
31%313%27%22%1
1602
16th to endDay
42%413%28%9%
1446
December1st to 15thDay
50%5%15%19%8%1
1440
16th to endDay
53%6%12%17%8%
1554
January1st to 15thNight
39%5%17%24%13%
2327
16th to endNight
41%5%15%25%11%
2496
February1st to 15thNight
48%5%14%21%8%1
2288
16th to endNight
35%5%13%24%18%2
1952
March1st to 15thNight
36%5%11%26%16%2
1994
16th to endNight
45%6%13%24%8%1
2112
April1st to 15thNight
38%5%9%27%16%1
1872
16th to endNight
43%5%13%22%13%1
1620
May1st to 15thNight
39%6%13%23%15%1
1620
16th to endNight
38%7%16%22%14%1
1613
June1st to 15thNight
29%8%14%28%15%3
1440
16th to endNight
20%7%14%30%22%3
1440
July1st to 15thNight
22%7%18%30%17%4
1481
16th to endNight
18%415%38%20%2
1594
August1st to 15thNight
25%9%16%29%17%2
1575
16th to endNight
32%311%24%19%8%
1605
September1st to 15thNight
29%5%11%26%21%5%
1735
16th to endNight
26%410%33%21%3
1815
October1st to 15thNight
34%49%23%24%3
1950
16th to endNight
32%413%26%21%2
2112
November1st to 15thNight
27%413%26%24%3
2254
16th to endNight
35%414%28%15%1
2512
December1st to 15thNight
45%5%15%23%9%
2520
16th to endNight
47%5%14%21%10%1
2668

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
21%8%38%25%5%
90
16th to endDay
22%6%42%20%7%
96
February1st to 15thDay
15%18%42%18%4
90
16th to endDay
16%18%32%24%6%2
81
March1st to 15thDay
13%18%48%14%4
90
16th to endDay
31%14%32%16%5%
96
April1st to 15thDay
15%21%34%21%6%1
194
16th to endDay
25%25%25%14%7%
450
May1st to 15thDay
14%25%28%22%8%1
468
16th to endDay
16%19%29%22%10%1
517
June1st to 15thDay
9%17%25%30%14%2
495
16th to endDay
5%17%33%28%12%2
495
July1st to 15thDay
10%10%23%28%23%4
475
16th to endDay
213%19%40%21%3
515
August1st to 15thDay
6%8%22%36%21%4
474
16th to endDay
9%11%21%31%21%3
413
September1st to 15thDay
10%6%32%29%19%1
168
16th to endDay
11%5%32%27%22%1
90
October1st to 15thDay
10%8%35%31%6%7%
90
16th to endDay
10%11%41%28%8%
96
November1st to 15thDay
10%5%31%35%14%3
90
16th to endDay
46%6%36%6%3
90
December1st to 15thDay
17%21%38%14%5%2
90
16th to endDay
23%21%35%15%3
96
January1st to 15thNight
10%28%27%27%6%
900
16th to endNight
14%26%29%24%5%
960
February1st to 15thNight
13%27%29%24%4
880
16th to endNight
10%23%37%21%6%
690
March1st to 15thNight
13%25%27%25%7%
554
16th to endNight
17%26%29%20%5%
576
April1st to 15thNight
14%28%30%23%3
539
16th to endNight
18%27%25%21%5%
540
May1st to 15thNight
14%25%27%23%8%
540
16th to endNight
13%21%27%26%9%
563
June1st to 15thNight
9%19%24%36%10%
540
16th to endNight
319%29%36%11%
540
July1st to 15thNight
412%23%38%21%
510
16th to endNight
317%14%45%18%
564
August1st to 15thNight
410%16%46%19%2
527
16th to endNight
11%10%19%34%21%2
525
September1st to 15thNight
12%12%23%30%18%1
495
16th to endNight
10%14%25%33%16%
492
October1st to 15thNight
16%14%31%25%10%1
630
16th to endNight
13%16%29%30%9%
704
November1st to 15thNight
9%24%29%25%10%
854
16th to endNight
14%25%32%20%7%
900
December1st to 15thNight
19%26%26%21%4
900
16th to endNight
16%25%27%25%6%
960
Page generated at 2017-08-13 13:16:38. Version ac04

Copyright 2017 A. Danko


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