Lexington(NE)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lexington(NE) clear sky chart from 2005-11-06 to 2025-07-21.

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	8% 6% 2 5% 4 3 4 3 5% 7% 53%	123788
	Night	7% 6% 2 5% 4 4 4 3 5% 7% 53%	124138
Transparency	Day	30% 5% 13% 27% 20% 4	123542
	Night	31% 5% 12% 26% 21% 5%	123976
Seeing	Day	11% 8% 31% 32% 15% 2	16736
	Night	10% 8% 36% 36% 9%	26638

By Month

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	9% 12% 3 7% 5% 4 3 3 4 6% 46%	3638
	11th to 20th	Day	5% 8% 3 8% 5% 5% 5% 4 5% 5% 48%	3640
	21st to end	Day	3 6% 3 9% 5% 4 4 3 5% 6% 52%	4376
February	1st to 10th	Day	7% 9% 3 9% 6% 5% 5% 4 5% 7% 39%	1875
	11th to 20th	Day	5% 8% 3 8% 5% 4 4 4 5% 7% 47%	1949
	21st to end	Day	7% 7% 3 5% 3 3 3 3 4 6% 56%	1650
March	1st to 10th	Day	11% 7% 2 4 2 2 3 2 3 5% 57%	4500
	11th to 20th	Day	8% 6% 2 5% 3 3 3 3 4 6% 58%	4970
	21st to end	Day	10% 8% 3 7% 4 3 4 4 5% 8% 46%	5464
April	1st to 10th	Day	10% 6% 2 4 4 4 4 4 6% 7% 50%	2382
	11th to 20th	Day	13% 8% 2 5% 4 3 4 4 5% 8% 44%	2439
	21st to end	Day	16% 6% 2 5% 4 3 4 3 6% 6% 46%	2600
May	1st to 10th	Day	9% 5% 2 5% 4 3 4 3 5% 7% 53%	5900
	11th to 20th	Day	10% 4 2 5% 3 3 4 2 4 7% 57%	5862
	21st to end	Day	19% 7% 2 5% 4 3 3 3 5% 7% 42%	6446
June	1st to 10th	Day	6% 4 1 4 3 3 3 4 7% 9% 56%	2785
	11th to 20th	Day	7% 4 1 4 4 3 5% 4 6% 8% 54%	2800
	21st to end	Day	5% 3 1 5% 3 4 4 4 6% 8% 57%	2800
July	1st to 10th	Day	7% 4 2 5% 4 3 4 3 5% 7% 54%	4570
	11th to 20th	Day	5% 4 1 5% 3 4 4 4 6% 10% 54%	4570
	21st to end	Day	4 3 1 4 4 4 4 4 5% 9% 58%	4558
August	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 6% 8% 47%	4103
	11th to 20th	Day	11% 6% 2 5% 4 4 4 4 6% 7% 46%	4041
	21st to end	Day	5% 4 2 5% 4 3 3 2 5% 7% 61%	4246
September	1st to 10th	Day	10% 4 2 4 4 3 3 3 4 6% 58%	2209
	11th to 20th	Day	8% 3 2 4 4 3 4 3 4 6% 59%	2090
	21st to end	Day	10% 4 1 4 2 3 3 2 3 6% 64%	2090
October	1st to 10th	Day	9% 3 1 1 1 1 1 2 2 5% 74%	3480
	11th to 20th	Day	5% 4 1 4 2 3 3 3 4 6% 65%	3180
	21st to end	Day	9% 5% 2 4 3 3 3 3 4 6% 60%	3099
November	1st to 10th	Day	8% 5% 1 5% 4 3 3 4 5% 6% 56%	1763
	11th to 20th	Day	6% 7% 1 3 3 3 3 3 4 5% 62%	1800
	21st to end	Day	8% 8% 2 5% 3 2 3 2 5% 7% 56%	1800
December	1st to 10th	Day	4 5% 2 5% 4 3 4 3 4 6% 61%	2940
	11th to 20th	Day	4 7% 2 6% 4 4 3 3 5% 6% 56%	3169
	21st to end	Day	10% 12% 4 10% 4 4 4 3 4 5% 41%	4004
January	1st to 10th	Night	7% 11% 4 11% 5% 4 4 3 5% 7% 39%	6327
	11th to 20th	Night	3 7% 3 7% 4 4 4 3 5% 7% 53%	6340
	21st to end	Night	3 8% 4 7% 5% 4 4 4 4 6% 51%	6598
February	1st to 10th	Night	8% 10% 3 7% 4 4 5% 4 5% 7% 44%	2540
	11th to 20th	Night	4 9% 3 7% 4 4 5% 4 6% 8% 46%	2338
	21st to end	Night	5% 7% 2 6% 5% 3 4 4 4 5% 55%	1980
March	1st to 10th	Night	9% 6% 2 5% 3 3 3 2 4 6% 58%	5374
	11th to 20th	Night	8% 6% 1 5% 3 2 3 3 5% 6% 58%	4989
	21st to end	Night	10% 8% 3 7% 5% 5% 5% 5% 6% 7% 40%	5467
April	1st to 10th	Night	11% 7% 2 5% 3 4 4 4 5% 6% 49%	2015
	11th to 20th	Night	12% 5% 2 5% 4 4 4 4 6% 7% 47%	1909
	21st to end	Night	13% 6% 2 4 3 3 4 3 6% 9% 47%	1800
May	1st to 10th	Night	15% 5% 2 5% 4 4 4 4 5% 6% 45%	4080
	11th to 20th	Night	8% 5% 2 4 3 4 4 4 6% 7% 53%	4053
	21st to end	Night	18% 7% 2 5% 4 4 4 3 5% 7% 41%	4451
June	1st to 10th	Night	6% 3 1 5% 3 3 5% 4 6% 9% 53%	1610
	11th to 20th	Night	9% 4 2 5% 3 3 4 4 5% 9% 52%	1600
	21st to end	Night	5% 4 1 4 4 4 5% 4 7% 9% 55%	1600
July	1st to 10th	Night	8% 4 2 5% 5% 4 4 4 6% 8% 50%	2620
	11th to 20th	Night	5% 3 1 5% 5% 6% 5% 4 7% 9% 49%	2620
	21st to end	Night	3 3 1 3 2 2 3 4 5% 9% 63%	3004
August	1st to 10th	Night	6% 4 2 5% 4 4 5% 4 8% 12% 47%	2836
	11th to 20th	Night	10% 5% 2 6% 4 4 4 4 6% 7% 48%	2798
	21st to end	Night	4 3 2 5% 3 4 5% 4 6% 9% 55%	3417
September	1st to 10th	Night	8% 4 2 4 3 2 3 2 4 6% 62%	1970
	11th to 20th	Night	6% 3 1 4 3 3 3 3 4 7% 62%	2090
	21st to end	Night	8% 3 1 4 3 2 3 2 4 6% 63%	2090
October	1st to 10th	Night	8% 2 1 3 2 2 1 2 3 4 72%	3480
	11th to 20th	Night	5% 4 1 4 2 2 2 2 3 6% 67%	3705
	21st to end	Night	7% 4 1 4 3 3 4 3 5% 7% 59%	4457
November	1st to 10th	Night	6% 4 1 4 3 3 3 3 5% 7% 61%	2535
	11th to 20th	Night	6% 6% 2 4 3 3 3 4 5% 6% 58%	2600
	21st to end	Night	7% 5% 2 5% 3 3 3 3 5% 8% 57%	2600
December	1st to 10th	Night	3 4 2 3 3 3 3 3 5% 6% 65%	4250
	11th to 20th	Night	4 5% 2 5% 4 3 3 4 6% 8% 57%	5021
	21st to end	Night	11% 12% 4 7% 4 3 3 3 5% 6% 41%	6974

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	40% 5% 12% 28% 15% 1	3639
	11th to 20th	Day	37% 8% 8% 24% 20% 3	3640
	21st to end	Day	32% 5% 14% 25% 19% 4	4376
February	1st to 10th	Day	43% 6% 14% 20% 12% 4	1875
	11th to 20th	Day	35% 7% 16% 23% 16% 4	1959
	21st to end	Day	29% 5% 14% 27% 19% 6%	1650
March	1st to 10th	Day	31% 3 8% 23% 28% 6%	4500
	11th to 20th	Day	28% 4 9% 24% 27% 8%	4970
	21st to end	Day	35% 8% 19% 27% 10% 1	5464
April	1st to 10th	Day	31% 7% 16% 26% 17% 3	2382
	11th to 20th	Day	38% 6% 15% 22% 16% 4	2442
	21st to end	Day	37% 7% 12% 27% 16% 1	2600
May	1st to 10th	Day	27% 6% 14% 28% 20% 5%	5900
	11th to 20th	Day	28% 6% 11% 27% 22% 6%	5866
	21st to end	Day	40% 7% 13% 25% 13% 2	6447
June	1st to 10th	Day	22% 8% 21% 33% 14% 2	2785
	11th to 20th	Day	27% 7% 15% 27% 18% 5%	2800
	21st to end	Day	24% 7% 13% 30% 21% 5%	2800
July	1st to 10th	Day	29% 5% 12% 25% 26% 3	4501
	11th to 20th	Day	25% 5% 17% 30% 19% 3	4495
	21st to end	Day	22% 5% 16% 28% 22% 7%	4414
August	1st to 10th	Day	33% 6% 15% 24% 19% 1	4090
	11th to 20th	Day	37% 5% 15% 24% 17% 1	4080
	21st to end	Day	24% 5% 15% 26% 20% 10%	4245
September	1st to 10th	Day	28% 6% 9% 24% 25% 8%	2209
	11th to 20th	Day	25% 7% 13% 27% 24% 4	2090
	21st to end	Day	24% 4 8% 32% 27% 5%	2090
October	1st to 10th	Day	17% 3 5% 24% 38% 14%	3480
	11th to 20th	Day	22% 3 13% 36% 20% 6%	3180
	21st to end	Day	27% 3 9% 31% 25% 5%	3099
November	1st to 10th	Day	27% 6% 12% 29% 23% 3	1763
	11th to 20th	Day	25% 5% 10% 29% 26% 6%	1800
	21st to end	Day	30% 4 13% 26% 23% 4	1800
December	1st to 10th	Day	25% 3 11% 33% 24% 4	2940
	11th to 20th	Day	29% 4 19% 30% 16% 1	3167
	21st to end	Day	47% 4 7% 27% 14% 1	4004
January	1st to 10th	Night	44% 5% 12% 22% 15% 2	6327
	11th to 20th	Night	30% 5% 13% 25% 24% 2	6340
	21st to end	Night	34% 6% 9% 24% 21% 5%	6598
February	1st to 10th	Night	39% 7% 12% 24% 14% 4	2540
	11th to 20th	Night	36% 5% 13% 28% 15% 3	2338
	21st to end	Night	30% 5% 11% 24% 22% 8%	1980
March	1st to 10th	Night	29% 4 7% 24% 28% 8%	5374
	11th to 20th	Night	27% 4 7% 22% 28% 13%	4989
	21st to end	Night	40% 8% 19% 21% 11% 1	5467
April	1st to 10th	Night	34% 6% 14% 24% 19% 3	2015
	11th to 20th	Night	34% 6% 14% 26% 17% 3	1909
	21st to end	Night	34% 6% 16% 27% 16% 2	1800
May	1st to 10th	Night	37% 7% 11% 26% 16% 2	4080
	11th to 20th	Night	28% 8% 15% 26% 19% 5%	4054
	21st to end	Night	40% 9% 13% 23% 13% 1	4452
June	1st to 10th	Night	25% 8% 22% 27% 15% 2	1610
	11th to 20th	Night	29% 8% 15% 27% 17% 5%	1600
	21st to end	Night	24% 8% 15% 29% 21% 3	1600
July	1st to 10th	Night	31% 6% 13% 30% 18% 2	2580
	11th to 20th	Night	29% 7% 17% 25% 18% 4	2572
	21st to end	Night	17% 5% 18% 25% 23% 11%	2910
August	1st to 10th	Night	29% 6% 17% 27% 19% 2	2826
	11th to 20th	Night	36% 5% 16% 26% 16% 1	2825
	21st to end	Night	27% 4 15% 28% 19% 8%	3417
September	1st to 10th	Night	24% 5% 9% 25% 26% 11%	1970
	11th to 20th	Night	23% 5% 12% 28% 25% 6%	2090
	21st to end	Night	24% 5% 8% 27% 30% 7%	2090
October	1st to 10th	Night	18% 3 6% 17% 46% 10%	3480
	11th to 20th	Night	20% 3 12% 29% 25% 11%	3705
	21st to end	Night	26% 3 10% 27% 28% 5%	4457
November	1st to 10th	Night	22% 4 12% 30% 24% 7%	2535
	11th to 20th	Night	25% 6% 10% 27% 25% 7%	2600
	21st to end	Night	27% 4 11% 27% 25% 5%	2600
December	1st to 10th	Night	20% 4 15% 37% 21% 3	4250
	11th to 20th	Night	26% 4 15% 35% 18% 3	5022
	21st to end	Night	44% 4 10% 28% 13% 1	6974

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	11% 8% 37% 30% 12% 2	300
	11th to 20th	Day	14% 12% 36% 29% 8%	300
	21st to end	Day	9% 8% 45% 24% 12% 2	330
February	1st to 10th	Day	11% 14% 45% 23% 7%	300
	11th to 20th	Day	9% 10% 45% 27% 7% 3	300
	21st to end	Day	12% 13% 48% 22% 4	249
March	1st to 10th	Day	14% 11% 41% 25% 9%	300
	11th to 20th	Day	15% 10% 36% 27% 11% 1	300
	21st to end	Day	18% 14% 39% 22% 5% 1	330
April	1st to 10th	Day	14% 20% 41% 19% 6% 1	482
	11th to 20th	Day	17% 16% 36% 26% 6%	560
	21st to end	Day	19% 14% 34% 22% 9% 1	700
May	1st to 10th	Day	14% 9% 34% 31% 11% 1	703
	11th to 20th	Day	17% 11% 31% 27% 13% 2	725
	21st to end	Day	16% 10% 31% 29% 12% 2	789
June	1st to 10th	Day	7% 6% 27% 34% 20% 6%	730
	11th to 20th	Day	8% 6% 33% 38% 14% 1	730
	21st to end	Day	7% 7% 31% 38% 16% 1	730
July	1st to 10th	Day	5% 5% 24% 37% 26% 4	721
	11th to 20th	Day	6% 3 20% 42% 27% 4	718
	21st to end	Day	6% 2 17% 44% 26% 6%	740
August	1st to 10th	Day	8% 2 17% 44% 26% 3	676
	11th to 20th	Day	9% 3 19% 45% 22% 2	665
	21st to end	Day	8% 3 18% 45% 23% 4	579
September	1st to 10th	Day	10% 3 25% 41% 19% 2	419
	11th to 20th	Day	4 6% 31% 34% 21% 4	300
	21st to end	Day	12% 9% 28% 31% 16% 3	300
October	1st to 10th	Day	19% 6% 24% 30% 15% 6%	300
	11th to 20th	Day	7% 9% 42% 27% 11% 3	300
	21st to end	Day	20% 13% 27% 30% 9% 1	330
November	1st to 10th	Day	13% 8% 39% 27% 11% 2	300
	11th to 20th	Day	11% 12% 37% 28% 11% 1	300
	21st to end	Day	15% 9% 40% 24% 10% 2	300
December	1st to 10th	Day	7% 9% 42% 30% 10% 1	300
	11th to 20th	Day	14% 9% 39% 29% 9% 1	300
	21st to end	Day	14% 13% 38% 28% 6% 1	330
January	1st to 10th	Night	10% 9% 38% 35% 8% 1	1000
	11th to 20th	Night	9% 11% 40% 33% 6% 1	1000
	21st to end	Night	8% 8% 45% 32% 7%	1100
February	1st to 10th	Night	12% 9% 45% 29% 5%	940
	11th to 20th	Night	8% 10% 44% 33% 5%	784
	21st to end	Night	9% 11% 44% 32% 4	660
March	1st to 10th	Night	12% 11% 41% 33% 3	800
	11th to 20th	Night	13% 9% 40% 32% 6%	609
	21st to end	Night	16% 12% 40% 28% 5%	660
April	1st to 10th	Night	14% 14% 42% 29% 2	600
	11th to 20th	Night	14% 14% 43% 26% 2	593
	21st to end	Night	17% 11% 36% 29% 7%	600
May	1st to 10th	Night	16% 8% 38% 33% 7%	600
	11th to 20th	Night	15% 9% 35% 33% 7% 1	591
	21st to end	Night	17% 7% 33% 32% 10%	650
June	1st to 10th	Night	8% 5% 32% 41% 14% 1	600
	11th to 20th	Night	10% 6% 38% 38% 8%	600
	21st to end	Night	6% 5% 35% 46% 10%	600
July	1st to 10th	Night	5% 3 29% 42% 20% 1	585
	11th to 20th	Night	3 1 24% 54% 16% 1	582
	21st to end	Night	4 1 19% 54% 21% 1	624
August	1st to 10th	Night	7% 2 18% 51% 21% 1	567
	11th to 20th	Night	9% 2 22% 50% 16%	564
	21st to end	Night	7% 2 23% 47% 20% 1	627
September	1st to 10th	Night	8% 3 27% 50% 11% 1	570
	11th to 20th	Night	6% 4 35% 39% 15% 1	570
	21st to end	Night	9% 6% 33% 37% 14%	570
October	1st to 10th	Night	15% 6% 33% 33% 12%	570
	11th to 20th	Night	12% 10% 35% 33% 10%	712
	21st to end	Night	13% 11% 33% 33% 10%	1035
November	1st to 10th	Night	8% 8% 37% 41% 6% 1	975
	11th to 20th	Night	9% 10% 37% 37% 7%	1000
	21st to end	Night	10% 8% 35% 36% 10% 1	1000
December	1st to 10th	Night	7% 10% 41% 37% 5%	1000
	11th to 20th	Night	12% 9% 39% 33% 7%	1000
	21st to end	Night	14% 10% 38% 33% 6%	1100

Page generated at 2025-07-18 00:10:04. Version ac07

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