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 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
34%
16719
21%
48991
10%
16673
44%
16673
26%
29994

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%
975
19%
2522
8%
970
36%
970
24%
1668
January16th to endNight
24%
1040
23%
2704
8%
1040
35%
1040
23%
1802
February1st to 15thNight
23%
955
12%
2483
5%
951
28%
951
19%
1788
February16th to endNight
24%
723
23%
2041
6%
723
38%
723
25%
1278
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
43%
540
17%
1440
5%
540
49%
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
59%
510
40%
786
July16th to endNight
62%
564
25%
1594
18%
531
72%
531
47%
779
August1st to 15thNight
62%
539
20%
1610
20%
536
66%
536
36%
905
August16th to endNight
55%
573
25%
1752
22%
573
63%
573
35%
980
September1st to 15thNight
49%
540
24%
1893
20%
540
60%
540
32%
996
September16th to endNight
47%
537
29%
1980
22%
537
61%
537
33%
991
October1st to 15thNight
34%
687
25%
2127
14%
687
43%
687
28%
1268
October16th to endNight
36%
768
26%
2304
13%
768
47%
768
32%
1318
November1st to 15thNight
32%
927
27%
2447
10%
927
43%
927
33%
1442
November16th to endNight
27%
975
25%
2722
9%
975
39%
975
29%
1640
December1st to 15thNight
23%
975
16%
2730
5%
975
31%
975
20%
1836
December16th to endNight
24%
1040
19%
2890
7%
1040
35%
1040
19%
2023

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%
49243
Night
10%6%24423447%48%
49182
Cloud CoverDay
11%6%25%5%2445%7%43%
49254
Night
10%6%24423447%48%
49186
Cloud CoverDay
11%6%25%42445%7%43%
49252
Night
10%6%24423347%48%
49186
TransparencyDay
39%6%14%24%13%1
48952
Night
35%5%13%26%16%2
48991
SeeingDay
12%14%29%26%13%2
6475
Night
12%21%27%27%9%
16720

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%36%7%45%45%7%39%
1746
16th to endDay
10%11%37%5%2445%7%36%
1872
February1st to 15thDay
10%9%5%9%5%35%45%6%33%
1710
16th to endDay
10%8%38%6%23447%38%
1588
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%6%10%41%
2340
16th to endDay
8%5%15%4245%6%8%47%
2450
September1st to 15thDay
11%5%23423446%51%
2065
16th to endDay
10%414323446%55%
1980
October1st to 15thDay
14%6%23323345%49%
1821
16th to endDay
13%6%25%42334449%
1920
November1st to 15thDay
9%5%15%324345%55%
1739
16th to endDay
12%8%34414348%43%
1566
December1st to 15thDay
11%10%37%434446%37%
1560
16th to endDay
12%9%5%9%6%3445%5%32%
1684
January1st to 15thNight
7%6%36%6%3446%7%42%
2522
16th to endNight
10%8%46%5%23336%45%
2704
February1st to 15thNight
12%8%5%7%6%3345%6%35%
2480
16th to endNight
9%6%35%42445%6%47%
2041
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
42144246%6%8%53%
1620
16th to endNight
9%324323336%55%
1752
September1st to 15thNight
9%313423446%56%
1893
16th to endNight
8%5%23213346%58%
1980
October1st to 15thNight
15%5%23323435%50%
2127
16th to endNight
11%5%14322345%54%
2304
November1st to 15thNight
9%423324347%54%
2447
16th to endNight
10%6%33323346%52%
2722
December1st to 15thNight
12%9%26%5%34446%42%
2730
16th to endNight
13%10%36%5%24347%38%
2890

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%36%7%45%45%6%39%
1746
16th to endDay
10%12%37%5%3435%7%36%
1872
February1st to 15thDay
10%9%5%9%5%3445%7%32%
1710
16th to endDay
11%8%37%6%23447%38%
1588
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%42%
2340
16th to endDay
8%415%4245%5%8%47%
2450
September1st to 15thDay
10%5%2441435%6%50%
2065
16th to endDay
10%314323445%55%
1980
October1st to 15thDay
14%5%24323345%48%
1821
16th to endDay
12%6%25%43334448%
1920
November1st to 15thDay
9%5%25%413345%55%
1739
16th to endDay
12%8%34423347%44%
1566
December1st to 15thDay
11%10%37%5%34446%37%
1560
16th to endDay
13%9%5%9%7%345%45%32%
1684
January1st to 15thNight
7%7%36%6%3445%7%42%
2522
16th to endNight
10%8%46%424336%45%
2704
February1st to 15thNight
12%9%48%6%34447%35%
2473
16th to endNight
9%6%36%42346%6%47%
2041
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%
1620
16th to endNight
9%324423336%56%
1752
September1st to 15thNight
9%412423447%55%
1893
16th to endNight
8%423213346%58%
1980
October1st to 15thNight
15%5%13323345%50%
2127
16th to endNight
11%5%14323435%54%
2304
November1st to 15thNight
8%5%23323347%54%
2447
16th to endNight
11%6%24322346%52%
2722
December1st to 15thNight
12%8%26%5%34346%41%
2730
16th to endNight
13%10%37%5%23346%38%
2890

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%26%7%45%45%6%39%
1746
16th to endDay
10%11%37%5%2445%7%36%
1872
February1st to 15thDay
10%9%5%9%6%35%45%7%32%
1710
16th to endDay
11%8%47%6%2345%7%38%
1588
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%43%
2340
16th to endDay
8%4244245%5%8%48%
2450
September1st to 15thDay
11%5%14324446%51%
2065
16th to endDay
10%41432335%6%55%
1980
October1st to 15thDay
15%5%23323345%49%
1821
16th to endDay
13%6%25%33334449%
1920
November1st to 15thDay
9%5%15%323345%54%
1739
16th to endDay
12%7%34424347%43%
1566
December1st to 15thDay
12%10%37%5%34446%37%
1560
16th to endDay
12%9%49%7%345%45%31%
1684
January1st to 15thNight
7%7%35%6%4446%7%42%
2522
16th to endNight
10%8%36%424236%45%
2704
February1st to 15thNight
12%9%38%6%3345%6%36%
2473
16th to endNight
9%6%35%42345%6%47%
2041
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
42244236%6%8%53%
1620
16th to endNight
9%324323336%56%
1752
September1st to 15thNight
10%313423347%55%
1893
16th to endNight
9%422212346%58%
1980
October1st to 15thNight
15%413323435%51%
2127
16th to endNight
11%5%13323345%54%
2304
November1st to 15thNight
9%5%23323347%54%
2447
16th to endNight
10%6%34323246%52%
2722
December1st to 15thNight
12%9%25%5%34346%41%
2730
16th to endNight
13%10%36%5%24346%38%
2890

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%6%17%21%10%
1747
16th to endDay
47%5%16%20%10%
1872
February1st to 15thDay
50%6%15%19%7%
1711
16th to endDay
44%7%11%21%12%2
1588
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%23%14%1
2326
16th to endDay
33%7%12%26%15%4
2450
September1st to 15thDay
33%5%12%27%18%2
2065
16th to endDay
29%5%11%32%19%
1980
October1st to 15thDay
37%410%25%20%1
1821
16th to endDay
38%412%23%18%3
1920
November1st to 15thDay
31%414%27%21%1
1739
16th to endDay
40%413%29%11%
1566
December1st to 15thDay
47%5%16%20%8%1
1560
16th to endDay
53%6%12%18%8%
1684
January1st to 15thNight
39%5%16%24%13%
2522
16th to endNight
40%5%15%25%11%
2704
February1st to 15thNight
48%5%14%20%9%1
2483
16th to endNight
36%5%13%24%17%2
2041
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
24%9%16%29%16%2
1610
16th to endNight
30%412%25%19%8%
1752
September1st to 15thNight
28%5%12%28%20%5%
1893
16th to endNight
26%410%33%20%3
1980
October1st to 15thNight
35%5%9%23%23%3
2127
16th to endNight
31%412%25%23%2
2304
November1st to 15thNight
29%413%25%23%3
2447
16th to endNight
33%413%30%16%1
2722
December1st to 15thNight
43%5%15%24%10%
2730
16th to endNight
47%5%13%21%10%1
2890

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
18%11%39%25%5%
135
16th to endDay
19%5%44%22%8%
144
February1st to 15thDay
16%17%42%20%2
135
16th to endDay
16%20%34%23%5%2
100
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
493
16th to endDay
9%9%22%32%21%4
490
September1st to 15thDay
9%5%32%29%19%3
220
16th to endDay
11%435%29%18%
135
October1st to 15thDay
20%7%34%25%5%7%
135
16th to endDay
12%13%38%23%10%
144
November1st to 15thDay
10%9%37%30%10%2
135
16th to endDay
34%8%37%15%3
135
December1st to 15thDay
13%19%42%17%5%1
135
16th to endDay
19%17%40%18%4
144
January1st to 15thNight
9%27%27%27%6%
975
16th to endNight
14%24%30%24%5%
1040
February1st to 15thNight
14%26%29%25%4
955
16th to endNight
11%23%37%21%6%
723
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%20%2
539
16th to endNight
10%9%19%34%22%2
573
September1st to 15thNight
11%11%23%30%20%2
540
16th to endNight
10%12%27%32%15%
537
October1st to 15thNight
17%14%30%25%9%1
687
16th to endNight
13%16%30%30%9%
768
November1st to 15thNight
10%23%30%25%9%
927
16th to endNight
13%24%33%21%7%
975
December1st to 15thNight
18%26%28%22%4
975
16th to endNight
16%23%27%26%5%
1040
Page generated at 2018-02-23 10:21:31. Version ac04

Copyright 2018 A. Danko


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