Nebraska City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Nebraska City clear sky chart from 2005-11-06 to 2026-07-16.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	11% 7% 3 7% 4 4 4 3 5% 7% 45%	137781
	Night	10% 7% 2 6% 4 4 4 3 5% 7% 48%	135210
Transparency	Day	39% 3 12% 27% 17% 2	141406
	Night	37% 3 12% 27% 19% 3	139652
Seeing	Day	14% 8% 28% 30% 16% 4	18108
	Night	14% 8% 31% 35% 12% 1	27950

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	9% 11% 4 13% 6% 5% 5% 4 4 5% 34%	5289
	11th to 20th	Day	6% 8% 3 8% 6% 6% 6% 4 6% 6% 40%	5310
	21st to end	Day	7% 12% 5% 10% 5% 5% 4 3 5% 6% 37%	5812
February	1st to 10th	Day	9% 12% 4 8% 6% 5% 4 3 6% 7% 35%	1890
	11th to 20th	Day	10% 9% 3 7% 5% 5% 5% 3 4 7% 40%	1870
	21st to end	Day	9% 8% 3 6% 5% 4 4 3 5% 7% 46%	1730
March	1st to 10th	Day	15% 8% 3 6% 3 3 3 2 3 5% 51%	5033
	11th to 20th	Day	11% 6% 2 5% 4 3 3 3 4 7% 51%	5090
	21st to end	Day	16% 9% 3 9% 5% 4 5% 3 5% 7% 33%	5583
April	1st to 10th	Day	16% 7% 2 6% 4 4 4 3 5% 6% 44%	2381
	11th to 20th	Day	15% 6% 2 6% 5% 4 4 3 5% 6% 43%	2579
	21st to end	Day	19% 7% 3 7% 5% 4 5% 3 4 7% 38%	2730
May	1st to 10th	Day	11% 6% 3 7% 4 4 4 4 5% 7% 45%	7617
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 5% 6% 49%	7627
	21st to end	Day	18% 8% 3 7% 4 3 4 4 5% 7% 37%	8607
June	1st to 10th	Day	7% 4 2 6% 4 3 4 5% 6% 9% 49%	2940
	11th to 20th	Day	8% 5% 2 4 4 4 4 4 6% 9% 49%	2940
	21st to end	Day	7% 5% 2 7% 5% 6% 6% 4 6% 7% 46%	2940
July	1st to 10th	Day	9% 4 2 6% 4 4 5% 4 7% 9% 46%	6062
	11th to 20th	Day	7% 5% 2 6% 5% 4 4 4 6% 8% 48%	5966
	21st to end	Day	6% 5% 2 5% 3 3 4 4 6% 9% 53%	6422
August	1st to 10th	Day	6% 4 2 6% 4 4 5% 5% 7% 10% 47%	4234
	11th to 20th	Day	12% 6% 2 5% 4 4 4 4 6% 9% 44%	4171
	21st to end	Day	6% 4 2 6% 4 4 5% 4 6% 9% 49%	4553
September	1st to 10th	Day	12% 4 1 4 3 3 4 3 4 6% 55%	2340
	11th to 20th	Day	10% 5% 1 5% 4 4 4 3 6% 7% 52%	2200
	21st to end	Day	12% 4 2 4 2 2 4 2 5% 6% 57%	2200
October	1st to 10th	Day	14% 5% 2 5% 3 2 3 2 5% 6% 53%	2035
	11th to 20th	Day	12% 6% 2 5% 2 2 3 3 4 5% 57%	2000
	21st to end	Day	13% 7% 2 7% 4 3 3 3 5% 7% 47%	2200
November	1st to 10th	Day	10% 6% 2 5% 4 2 4 2 5% 5% 56%	1912
	11th to 20th	Day	10% 6% 2 6% 5% 3 4 3 4 7% 50%	1825
	21st to end	Day	13% 8% 3 6% 4 3 4 3 5% 7% 43%	1680
December	1st to 10th	Day	5% 5% 2 6% 4 5% 4 3 5% 7% 53%	2690
	11th to 20th	Day	9% 8% 2 9% 6% 4 4 3 5% 6% 43%	3088
	21st to end	Day	18% 10% 5% 14% 5% 4 3 3 4 5% 30%	4235
January	1st to 10th	Night	10% 9% 4 16% 6% 5% 4 3 4 6% 32%	7634
	11th to 20th	Night	5% 7% 3 7% 4 5% 7% 4 6% 7% 46%	7680
	21st to end	Night	9% 13% 4 9% 4 4 4 3 4 5% 40%	8402
February	1st to 10th	Night	11% 11% 3 8% 6% 4 4 3 4 5% 41%	2730
	11th to 20th	Night	9% 9% 3 7% 4 4 4 4 6% 7% 42%	2654
	21st to end	Night	9% 7% 2 7% 4 5% 3 3 4 6% 51%	2076
March	1st to 10th	Night	13% 6% 2 5% 3 3 3 3 3 6% 51%	5040
	11th to 20th	Night	9% 6% 2 5% 3 2 3 3 4 6% 57%	5090
	21st to end	Night	14% 9% 3 7% 4 4 4 3 6% 8% 38%	5588
April	1st to 10th	Night	13% 6% 3 6% 4 4 4 3 5% 6% 46%	2238
	11th to 20th	Night	11% 7% 3 6% 4 4 4 3 5% 7% 47%	1988
	21st to end	Night	18% 7% 2 5% 4 3 4 3 4 6% 45%	1890
May	1st to 10th	Night	12% 5% 2 6% 4 4 3 3 4 5% 51%	5266
	11th to 20th	Night	14% 4 2 4 3 3 3 2 4 7% 54%	5265
	21st to end	Night	19% 6% 2 6% 4 3 4 3 5% 6% 42%	5562
June	1st to 10th	Night	6% 4 2 5% 4 3 4 4 7% 9% 53%	1680
	11th to 20th	Night	6% 4 1 4 3 3 4 4 8% 9% 53%	1680
	21st to end	Night	5% 3 2 4 3 3 4 4 7% 8% 57%	1680
July	1st to 10th	Night	7% 5% 2 6% 4 3 4 4 5% 7% 52%	4117
	11th to 20th	Night	5% 4 2 5% 4 4 4 4 6% 9% 53%	4122
	21st to end	Night	6% 3 1 4 4 4 4 4 7% 10% 54%	4449
August	1st to 10th	Night	3 3 1 4 3 3 4 3 5% 9% 60%	2926
	11th to 20th	Night	12% 4 2 4 3 3 4 3 5% 7% 53%	2888
	21st to end	Night	6% 4 1 5% 3 3 3 3 5% 8% 58%	3351
September	1st to 10th	Night	10% 3 2 4 3 4 3 3 4 7% 57%	2056
	11th to 20th	Night	8% 4 1 5% 3 3 4 4 5% 7% 56%	2200
	21st to end	Night	8% 4 1 4 3 4 3 4 4 5% 60%	2200
October	1st to 10th	Night	12% 6% 1 4 3 3 3 3 5% 6% 53%	2344
	11th to 20th	Night	12% 5% 2 4 3 3 4 3 4 6% 56%	2400
	21st to end	Night	15% 6% 2 5% 3 3 4 3 4 5% 51%	2640
November	1st to 10th	Night	9% 4 2 4 3 3 3 3 6% 7% 57%	2603
	11th to 20th	Night	10% 6% 2 5% 3 4 3 3 5% 7% 53%	2792
	21st to end	Night	13% 7% 2 5% 4 3 3 3 4 6% 50%	2940
December	1st to 10th	Night	5% 5% 2 5% 4 4 4 3 5% 8% 53%	4720
	11th to 20th	Night	10% 8% 3 7% 4 4 4 3 5% 7% 47%	5339
	21st to end	Night	17% 13% 5% 10% 4 3 3 3 4 5% 33%	6980

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	53% 3 11% 22% 10% 1	5290
	11th to 20th	Day	44% 2 12% 22% 17% 3	5310
	21st to end	Day	50% 2 15% 22% 11%	5812
February	1st to 10th	Day	49% 2 15% 22% 10% 1	1890
	11th to 20th	Day	46% 2 10% 25% 13% 3	1879
	21st to end	Day	40% 3 12% 27% 16% 2	1730
March	1st to 10th	Day	40% 2 8% 27% 18% 6%	5033
	11th to 20th	Day	36% 2 8% 27% 24% 4	5090
	21st to end	Day	52% 3 20% 19% 5% 2	5585
April	1st to 10th	Day	43% 3 11% 28% 13% 2	2381
	11th to 20th	Day	43% 2 13% 24% 15% 2	2579
	21st to end	Day	48% 3 10% 25% 14% 1	2730
May	1st to 10th	Day	40% 3 8% 30% 18% 2	7655
	11th to 20th	Day	37% 3 9% 26% 22% 3	7631
	21st to end	Day	47% 3 9% 25% 15% 1	8621
June	1st to 10th	Day	32% 4 18% 29% 15% 2	2940
	11th to 20th	Day	32% 3 14% 31% 18% 2	2940
	21st to end	Day	36% 4 13% 30% 14% 4	2940
July	1st to 10th	Day	33% 5% 14% 31% 16% 1	5998
	11th to 20th	Day	34% 5% 13% 28% 18% 2	5897
	21st to end	Day	27% 5% 18% 33% 15% 2	6240
August	1st to 10th	Day	30% 5% 17% 29% 17% 2	4220
	11th to 20th	Day	37% 4 15% 26% 17%	4210
	21st to end	Day	33% 5% 14% 28% 16% 5%	4552
September	1st to 10th	Day	32% 3 11% 30% 20% 5%	2340
	11th to 20th	Day	33% 2 11% 33% 20% 1	2200
	21st to end	Day	29% 2 8% 33% 25% 1	2200
October	1st to 10th	Day	21% 1 7% 21% 47% 3	3308
	11th to 20th	Day	21% 1 10% 31% 29% 7%	3240
	21st to end	Day	35% 2 8% 28% 23% 3	3538
November	1st to 10th	Day	32% 2 12% 30% 20% 3	1912
	11th to 20th	Day	37% 2 12% 28% 19% 1	1825
	21st to end	Day	43% 3 11% 29% 13% 1	1680
December	1st to 10th	Day	32% 3 18% 32% 15%	2690
	11th to 20th	Day	43% 2 16% 28% 10%	3085
	21st to end	Day	59% 2 12% 20% 6%	4235
January	1st to 10th	Night	55% 3 12% 18% 11% 1	7635
	11th to 20th	Night	39% 2 11% 27% 19% 2	7680
	21st to end	Night	49% 2 13% 18% 16% 2	8402
February	1st to 10th	Night	47% 2 13% 22% 13% 3	2730
	11th to 20th	Night	42% 3 13% 25% 15% 3	2655
	21st to end	Night	36% 2 9% 26% 22% 5%	2076
March	1st to 10th	Night	37% 1 6% 29% 24% 3	5040
	11th to 20th	Night	30% 2 6% 28% 25% 8%	5090
	21st to end	Night	46% 3 19% 25% 7% 1	5588
April	1st to 10th	Night	40% 2 9% 27% 17% 3	2238
	11th to 20th	Night	38% 3 10% 28% 18% 4	1988
	21st to end	Night	42% 3 12% 23% 18% 2	1890
May	1st to 10th	Night	37% 2 8% 27% 23% 3	5293
	11th to 20th	Night	34% 2 10% 24% 26% 5%	5266
	21st to end	Night	44% 3 10% 25% 16% 1	5573
June	1st to 10th	Night	28% 5% 14% 33% 17% 4	1680
	11th to 20th	Night	26% 4 14% 31% 21% 5%	1680
	21st to end	Night	25% 4 14% 31% 22% 3	1680
July	1st to 10th	Night	32% 4 13% 30% 19% 3	4074
	11th to 20th	Night	28% 5% 14% 28% 22% 3	4071
	21st to end	Night	25% 7% 16% 31% 19% 1	4320
August	1st to 10th	Night	23% 3 16% 35% 21% 2	2916
	11th to 20th	Night	31% 4 14% 30% 19% 2	2915
	21st to end	Night	26% 3 16% 29% 18% 8%	3351
September	1st to 10th	Night	29% 2 11% 28% 24% 7%	2056
	11th to 20th	Night	29% 3 12% 34% 20% 3	2200
	21st to end	Night	28% 3 7% 29% 30% 4	2200
October	1st to 10th	Night	21% 2 6% 20% 47% 4	3838
	11th to 20th	Night	22% 2 7% 30% 30% 10%	3899
	21st to end	Night	35% 3 8% 29% 24% 2	4252
November	1st to 10th	Night	28% 2 14% 28% 24% 4	2603
	11th to 20th	Night	33% 2 11% 32% 20% 3	2792
	21st to end	Night	38% 2 12% 28% 18% 2	2940
December	1st to 10th	Night	31% 4 13% 35% 16% 1	4720
	11th to 20th	Night	39% 3 15% 30% 13%	5341
	21st to end	Night	56% 2 11% 23% 7% 1	6980

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	18% 12% 34% 26% 8% 2	330
	11th to 20th	Day	18% 15% 33% 25% 8%	330
	21st to end	Day	13% 10% 42% 27% 7% 1	363
February	1st to 10th	Day	16% 14% 45% 20% 5%	330
	11th to 20th	Day	17% 15% 35% 25% 7% 1	330
	21st to end	Day	11% 16% 40% 27% 5%	273
March	1st to 10th	Day	16% 12% 41% 24% 6%	330
	11th to 20th	Day	28% 11% 28% 22% 10% 1	330
	21st to end	Day	23% 18% 33% 21% 3 1	363
April	1st to 10th	Day	24% 12% 38% 20% 5%	401
	11th to 20th	Day	21% 12% 35% 23% 8%	617
	21st to end	Day	22% 11% 35% 20% 11% 1	750
May	1st to 10th	Day	18% 9% 33% 26% 13% 3	753
	11th to 20th	Day	18% 7% 29% 29% 15% 2	775
	21st to end	Day	20% 5% 27% 31% 15% 3	844
June	1st to 10th	Day	7% 4 22% 30% 29% 8%	780
	11th to 20th	Day	10% 3 27% 34% 21% 5%	780
	21st to end	Day	9% 5% 31% 36% 17% 3	780
July	1st to 10th	Day	9% 2 15% 32% 31% 11%	771
	11th to 20th	Day	6% 2 18% 41% 25% 8%	744
	21st to end	Day	8% 2 13% 40% 30% 7%	794
August	1st to 10th	Day	7% 3 17% 42% 26% 5%	726
	11th to 20th	Day	9% 3 16% 42% 25% 5%	715
	21st to end	Day	10% 1 18% 36% 28% 7%	733
September	1st to 10th	Day	12% 3 22% 36% 21% 7%	470
	11th to 20th	Day	8% 2 23% 37% 20% 10%	330
	21st to end	Day	16% 4 23% 34% 17% 5%	330
October	1st to 10th	Day	18% 6% 23% 31% 14% 8%	330
	11th to 20th	Day	9% 15% 40% 24% 11% 1	330
	21st to end	Day	19% 14% 34% 23% 7% 3	363
November	1st to 10th	Day	17% 10% 36% 27% 7% 2	330
	11th to 20th	Day	18% 13% 38% 23% 8%	330
	21st to end	Day	23% 12% 31% 25% 9% 1	330
December	1st to 10th	Day	9% 12% 38% 30% 8% 2	330
	11th to 20th	Day	18% 13% 32% 28% 9%	330
	21st to end	Day	21% 13% 38% 24% 4 1	363
January	1st to 10th	Night	12% 10% 35% 34% 8%	1050
	11th to 20th	Night	14% 14% 34% 30% 7%	1050
	21st to end	Night	16% 8% 39% 30% 6%	1155
February	1st to 10th	Night	16% 11% 38% 30% 5%	1050
	11th to 20th	Night	14% 11% 40% 31% 5%	1020
	21st to end	Night	12% 11% 41% 29% 6% 1	692
March	1st to 10th	Night	14% 12% 38% 29% 7%	641
	11th to 20th	Night	19% 7% 36% 32% 6%	630
	21st to end	Night	23% 9% 37% 25% 5%	693
April	1st to 10th	Night	17% 14% 38% 25% 6%	630
	11th to 20th	Night	15% 14% 36% 30% 4	623
	21st to end	Night	20% 7% 35% 30% 7%	630
May	1st to 10th	Night	17% 7% 28% 38% 9% 1	630
	11th to 20th	Night	17% 7% 27% 38% 11% 1	621
	21st to end	Night	17% 5% 25% 37% 15%	683
June	1st to 10th	Night	7% 3 22% 47% 20% 1	630
	11th to 20th	Night	8% 2 28% 44% 17% 1	630
	21st to end	Night	6% 4 28% 46% 16%	630
July	1st to 10th	Night	8% 2 13% 41% 34% 2	615
	11th to 20th	Night	4 1 16% 48% 29% 2	597
	21st to end	Night	4 1 14% 51% 28% 2	657
August	1st to 10th	Night	6% 2 15% 51% 24% 3	597
	11th to 20th	Night	8% 3 13% 49% 25% 3	594
	21st to end	Night	9% 1 18% 43% 26% 3	660
September	1st to 10th	Night	12% 3 23% 38% 22% 3	600
	11th to 20th	Night	10% 3 26% 40% 21% 2	600
	21st to end	Night	12% 3 26% 39% 20% 1	600
October	1st to 10th	Night	15% 5% 29% 34% 15% 2	744
	11th to 20th	Night	15% 8% 36% 33% 7%	800
	21st to end	Night	20% 10% 30% 32% 8%	880
November	1st to 10th	Night	10% 10% 33% 37% 10%	963
	11th to 20th	Night	14% 12% 38% 30% 7%	1050
	21st to end	Night	17% 10% 35% 29% 9%	1050
December	1st to 10th	Night	13% 11% 36% 33% 6%	1050
	11th to 20th	Night	17% 9% 34% 32% 7%	1050
	21st to end	Night	20% 10% 35% 30% 5%	1155

Page generated at 2026-07-13 02:14:49. Version ac07

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