Scottsbluff
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Scottsbluff clear sky chart from 2005-11-06 to 2026-09-29.

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	7% 5% 2 5% 3 4 4 4 6% 8% 55%	158055
	Night	7% 5% 2 6% 4 4 4 4 6% 7% 52%	150929
Transparency	Day	27% 6% 13% 26% 21% 7%	152916
	Night	30% 6% 14% 27% 18% 5%	147080
Seeing	Day	10% 9% 28% 31% 18% 4	18431
	Night	9% 7% 35% 39% 9%	28296

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	3 7% 3 8% 5% 4 3 3 5% 6% 53%	4720
	11th to 20th	Day	3 7% 3 8% 5% 5% 5% 4 6% 7% 46%	4740
	21st to end	Day	2 5% 2 7% 4 4 4 3 5% 7% 56%	5459
February	1st to 10th	Day	4 9% 3 7% 5% 5% 4 3 5% 8% 46%	1896
	11th to 20th	Day	5% 8% 4 7% 4 4 4 3 6% 7% 47%	2049
	21st to end	Day	5% 6% 2 6% 4 4 4 3 5% 6% 55%	1730
March	1st to 10th	Day	8% 11% 2 5% 3 3 3 3 4 6% 52%	4600
	11th to 20th	Day	7% 6% 2 4 3 3 3 3 4 6% 59%	4777
	21st to end	Day	9% 7% 2 6% 4 4 4 4 6% 8% 45%	6101
April	1st to 10th	Day	10% 7% 2 4 4 4 4 4 6% 6% 49%	2520
	11th to 20th	Day	14% 6% 2 6% 4 4 5% 4 5% 7% 44%	2491
	21st to end	Day	12% 6% 2 5% 4 5% 4 3 6% 7% 46%	2600
May	1st to 10th	Day	10% 5% 2 5% 3 4 4 3 5% 7% 52%	7655
	11th to 20th	Day	10% 4 2 4 3 4 4 4 6% 8% 50%	8135
	21st to end	Day	12% 5% 2 5% 4 4 4 4 6% 7% 48%	9026
June	1st to 10th	Day	6% 3 1 4 4 4 4 5% 6% 9% 54%	2940
	11th to 20th	Day	8% 3 2 4 3 3 4 4 6% 9% 54%	2940
	21st to end	Day	5% 2 1 3 3 4 4 4 6% 9% 58%	2940
July	1st to 10th	Day	4 3 1 3 3 3 4 4 6% 8% 61%	8249
	11th to 20th	Day	3 2 1 2 2 3 4 3 6% 8% 66%	8250
	21st to end	Day	6% 3 1 4 4 5% 5% 4 8% 10% 50%	8957
August	1st to 10th	Day	6% 3 1 3 3 3 4 4 5% 8% 60%	7977
	11th to 20th	Day	3 3 1 4 3 4 5% 4 6% 8% 59%	7003
	21st to end	Day	6% 3 2 5% 4 4 5% 4 7% 9% 50%	7751
September	1st to 10th	Day	6% 3 1 3 2 3 3 2 5% 5% 65%	2520
	11th to 20th	Day	8% 2 1 4 3 3 3 3 4 7% 62%	2433
	21st to end	Day	8% 3 1 3 2 2 2 3 5% 6% 64%	2288
October	1st to 10th	Day	7% 3 1 2 1 2 2 2 3 4 74%	3435
	11th to 20th	Day	8% 4 2 4 3 3 3 3 4 6% 61%	3250
	21st to end	Day	7% 6% 1 5% 3 3 3 3 5% 7% 57%	3206
November	1st to 10th	Day	4 6% 2 4 3 3 4 3 6% 8% 59%	1853
	11th to 20th	Day	3 4 1 4 3 3 3 3 7% 7% 60%	1890
	21st to end	Day	5% 6% 2 4 3 3 4 3 5% 7% 59%	1776
December	1st to 10th	Day	3 4 2 4 3 3 3 3 6% 7% 63%	2700
	11th to 20th	Day	3 4 1 4 2 3 3 3 5% 8% 64%	3106
	21st to end	Day	7% 8% 2 6% 4 4 4 4 5% 8% 48%	4092
January	1st to 10th	Night	4 9% 3 7% 4 4 5% 3 5% 6% 49%	8201
	11th to 20th	Night	2 6% 3 8% 5% 4 4 4 5% 8% 50%	8250
	21st to end	Night	2 5% 3 8% 5% 5% 5% 4 4 6% 54%	8810
February	1st to 10th	Night	4 10% 3 7% 4 5% 4 4 6% 6% 46%	2722
	11th to 20th	Night	6% 8% 3 7% 5% 4 5% 4 6% 7% 45%	2458
	21st to end	Night	4 7% 2 7% 4 3 4 3 6% 7% 53%	2076
March	1st to 10th	Night	8% 12% 3 5% 3 3 3 2 3 4 54%	5494
	11th to 20th	Night	7% 6% 2 5% 3 3 3 3 4 5% 58%	5425
	21st to end	Night	11% 7% 2 7% 4 5% 5% 4 7% 8% 40%	5094
April	1st to 10th	Night	12% 6% 2 6% 3 4 4 3 6% 7% 48%	2100
	11th to 20th	Night	11% 6% 2 6% 5% 4 4 3 5% 6% 48%	2077
	21st to end	Night	13% 8% 3 6% 4 4 4 4 5% 6% 43%	2017
May	1st to 10th	Night	13% 7% 2 6% 3 4 4 3 5% 5% 48%	5292
	11th to 20th	Night	11% 5% 2 4 3 3 4 4 6% 7% 51%	4742
	21st to end	Night	15% 5% 2 6% 4 4 5% 4 6% 8% 42%	5181
June	1st to 10th	Night	8% 5% 1 4 3 4 5% 4 6% 9% 52%	1680
	11th to 20th	Night	8% 3 1 4 4 4 4 4 6% 10% 52%	1680
	21st to end	Night	6% 3 1 3 3 5% 4 4 7% 10% 54%	1680
July	1st to 10th	Night	4 3 2 5% 5% 5% 6% 5% 7% 8% 49%	4740
	11th to 20th	Night	4 2 1 3 3 3 4 4 6% 9% 61%	4740
	21st to end	Night	5% 4 2 7% 5% 5% 6% 5% 7% 9% 45%	5152
August	1st to 10th	Night	9% 3 1 4 4 4 5% 4 6% 9% 52%	4827
	11th to 20th	Night	5% 3 2 5% 4 5% 5% 4 7% 9% 50%	5853
	21st to end	Night	6% 4 2 6% 4 5% 5% 5% 7% 9% 46%	6465
September	1st to 10th	Night	6% 4 2 4 4 3 4 3 5% 7% 59%	2100
	11th to 20th	Night	8% 3 2 5% 3 3 3 4 4 7% 57%	2186
	21st to end	Night	8% 3 1 5% 3 3 4 3 5% 4 61%	2288
October	1st to 10th	Night	7% 2 1 2 2 2 2 2 2 4 74%	3746
	11th to 20th	Night	9% 3 1 4 2 3 4 3 5% 6% 60%	3898
	21st to end	Night	8% 4 1 4 3 3 4 4 5% 6% 57%	4561
November	1st to 10th	Night	6% 4 2 5% 3 3 4 2 5% 8% 57%	2665
	11th to 20th	Night	5% 6% 1 5% 3 4 3 3 6% 7% 58%	2730
	21st to end	Night	5% 7% 2 5% 3 3 3 3 5% 6% 58%	2840
December	1st to 10th	Night	3 4 1 4 4 3 3 3 5% 6% 63%	4710
	11th to 20th	Night	3 4 2 5% 4 4 5% 4 6% 8% 56%	5321
	21st to end	Night	8% 8% 3 6% 4 4 4 4 6% 8% 46%	7128

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	32% 4 14% 29% 20% 1	4723
	11th to 20th	Day	35% 6% 14% 23% 18% 4	4740
	21st to end	Day	28% 4 14% 30% 21% 3	5459
February	1st to 10th	Day	37% 6% 16% 23% 16% 3	1896
	11th to 20th	Day	36% 6% 12% 26% 17% 4	2059
	21st to end	Day	29% 6% 13% 28% 19% 5%	1730
March	1st to 10th	Day	32% 4 7% 27% 27% 2	4600
	11th to 20th	Day	26% 4 14% 26% 27% 3	4777
	21st to end	Day	34% 8% 15% 28% 13% 1	6101
April	1st to 10th	Day	33% 7% 16% 26% 15% 4	2520
	11th to 20th	Day	37% 8% 12% 21% 18% 4	2494
	21st to end	Day	35% 7% 13% 27% 16% 2	2600
May	1st to 10th	Day	29% 8% 12% 31% 15% 4	7655
	11th to 20th	Day	30% 7% 11% 25% 21% 6%	8139
	21st to end	Day	32% 7% 14% 26% 18% 3	9027
June	1st to 10th	Day	24% 10% 17% 28% 16% 4	2940
	11th to 20th	Day	26% 8% 12% 27% 20% 8%	2940
	21st to end	Day	21% 7% 12% 26% 26% 9%	2940
July	1st to 10th	Day	20% 5% 8% 27% 28% 12%	8181
	11th to 20th	Day	16% 4 9% 27% 25% 20%	8175
	21st to end	Day	26% 6% 15% 19% 20% 14%	8759
August	1st to 10th	Day	22% 5% 11% 22% 24% 16%	6317
	11th to 20th	Day	27% 7% 14% 24% 19% 8%	5519
	21st to end	Day	23% 7% 19% 23% 17% 12%	6078
September	1st to 10th	Day	21% 4 8% 23% 30% 15%	2520
	11th to 20th	Day	22% 4 9% 25% 27% 13%	2433
	21st to end	Day	21% 4 10% 25% 33% 7%	2288
October	1st to 10th	Day	17% 3 7% 19% 31% 23%	3435
	11th to 20th	Day	25% 4 10% 32% 22% 6%	3250
	21st to end	Day	27% 4 13% 28% 24% 4	3206
November	1st to 10th	Day	24% 5% 15% 28% 21% 8%	1853
	11th to 20th	Day	21% 5% 14% 30% 24% 5%	1890
	21st to end	Day	26% 4 14% 29% 24% 4	1776
December	1st to 10th	Day	20% 5% 14% 34% 25% 3	2700
	11th to 20th	Day	19% 4 16% 39% 19% 3	3104
	21st to end	Day	33% 6% 12% 33% 15% 1	4092
January	1st to 10th	Night	34% 5% 10% 33% 15% 2	8202
	11th to 20th	Night	31% 5% 17% 26% 16% 5%	8250
	21st to end	Night	32% 5% 13% 29% 19% 3	8810
February	1st to 10th	Night	36% 7% 15% 27% 13% 2	2722
	11th to 20th	Night	36% 8% 13% 25% 15% 3	2458
	21st to end	Night	31% 6% 11% 29% 20% 3	2076
March	1st to 10th	Night	33% 6% 7% 24% 26% 5%	5494
	11th to 20th	Night	28% 5% 12% 23% 31% 3	5425
	21st to end	Night	38% 10% 21% 19% 12% 1	5094
April	1st to 10th	Night	35% 7% 14% 23% 16% 4	2100
	11th to 20th	Night	35% 7% 13% 24% 17% 4	2077
	21st to end	Night	40% 8% 11% 26% 14% 1	2017
May	1st to 10th	Night	36% 7% 11% 27% 17% 1	5293
	11th to 20th	Night	30% 8% 15% 29% 12% 5%	4743
	21st to end	Night	38% 9% 16% 27% 9% 1	5182
June	1st to 10th	Night	27% 9% 24% 25% 13% 3	1680
	11th to 20th	Night	26% 8% 18% 23% 18% 7%	1680
	21st to end	Night	24% 8% 15% 25% 21% 6%	1680
July	1st to 10th	Night	29% 6% 14% 24% 21% 5%	4700
	11th to 20th	Night	20% 5% 16% 26% 20% 14%	4692
	21st to end	Night	34% 7% 17% 20% 16% 7%	5038
August	1st to 10th	Night	28% 6% 13% 24% 22% 7%	3811
	11th to 20th	Night	32% 9% 17% 24% 14% 5%	4613
	21st to end	Night	25% 8% 26% 18% 16% 8%	5069
September	1st to 10th	Night	25% 5% 9% 24% 25% 11%	2100
	11th to 20th	Night	26% 6% 10% 25% 22% 11%	2186
	21st to end	Night	26% 5% 8% 27% 24% 10%	2288
October	1st to 10th	Night	17% 3 7% 18% 32% 23%	3746
	11th to 20th	Night	24% 4 13% 31% 21% 6%	3898
	21st to end	Night	27% 5% 11% 29% 20% 8%	4561
November	1st to 10th	Night	25% 6% 13% 27% 24% 5%	2665
	11th to 20th	Night	24% 6% 11% 30% 22% 6%	2730
	21st to end	Night	27% 5% 11% 31% 21% 5%	2840
December	1st to 10th	Night	22% 4 14% 36% 21% 2	4710
	11th to 20th	Night	26% 4 13% 39% 15% 2	5322
	21st to end	Night	35% 6% 12% 33% 14% 1	7128

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	10% 9% 33% 32% 14% 2	330
	11th to 20th	Day	12% 14% 36% 30% 8%	330
	21st to end	Day	8% 11% 45% 28% 7% 1	363
February	1st to 10th	Day	8% 16% 48% 23% 5%	330
	11th to 20th	Day	7% 15% 43% 27% 6% 2	330
	21st to end	Day	14% 17% 37% 27% 5%	273
March	1st to 10th	Day	9% 14% 35% 28% 13% 1	330
	11th to 20th	Day	12% 13% 35% 27% 11% 2	389
	21st to end	Day	12% 16% 36% 26% 9% 2	594
April	1st to 10th	Day	16% 16% 35% 23% 9% 1	540
	11th to 20th	Day	17% 18% 33% 23% 8% 2	532
	21st to end	Day	16% 12% 31% 27% 13% 2	620
May	1st to 10th	Day	16% 12% 25% 29% 14% 4	753
	11th to 20th	Day	17% 8% 24% 30% 17% 4	775
	21st to end	Day	13% 10% 28% 28% 17% 4	844
June	1st to 10th	Day	6% 5% 24% 34% 24% 7%	780
	11th to 20th	Day	9% 8% 29% 35% 17% 3	780
	21st to end	Day	7% 7% 26% 32% 24% 4	780
July	1st to 10th	Day	6% 2 18% 39% 29% 6%	771
	11th to 20th	Day	5% 2 18% 38% 31% 6%	768
	21st to end	Day	6% 2 16% 35% 36% 5%	849
August	1st to 10th	Day	6% 2 19% 39% 29% 5%	743
	11th to 20th	Day	5% 4 19% 36% 26% 11%	557
	21st to end	Day	5% 3 24% 33% 25% 11%	627
September	1st to 10th	Day	5% 5% 22% 32% 28% 9%	570
	11th to 20th	Day	8% 3 20% 33% 26% 10%	483
	21st to end	Day	8% 8% 21% 32% 20% 12%	354
October	1st to 10th	Day	12% 7% 25% 23% 22% 12%	330
	11th to 20th	Day	10% 12% 29% 27% 16% 6%	330
	21st to end	Day	9% 12% 33% 27% 15% 4	363
November	1st to 10th	Day	6% 11% 33% 32% 13% 4	330
	11th to 20th	Day	5% 12% 35% 32% 15% 2	330
	21st to end	Day	13% 7% 30% 34% 15% 2	330
December	1st to 10th	Day	10% 12% 39% 27% 10% 1	330
	11th to 20th	Day	10% 14% 41% 25% 10%	330
	21st to end	Day	13% 12% 37% 29% 7% 1	363
January	1st to 10th	Night	8% 11% 38% 34% 9%	1050
	11th to 20th	Night	8% 13% 43% 30% 5% 1	1050
	21st to end	Night	8% 9% 44% 33% 5%	1081
February	1st to 10th	Night	8% 9% 50% 28% 5%	840
	11th to 20th	Night	10% 9% 42% 34% 5%	824
	21st to end	Night	8% 13% 45% 30% 4	692
March	1st to 10th	Night	10% 10% 39% 34% 6%	840
	11th to 20th	Night	12% 7% 36% 39% 6%	840
	21st to end	Night	14% 12% 37% 33% 4	693
April	1st to 10th	Night	16% 11% 36% 33% 5%	630
	11th to 20th	Night	12% 10% 40% 33% 4	623
	21st to end	Night	17% 10% 31% 34% 8%	630
May	1st to 10th	Night	17% 8% 31% 35% 10% 1	630
	11th to 20th	Night	16% 6% 29% 39% 10%	621
	21st to end	Night	13% 6% 31% 38% 11%	683
June	1st to 10th	Night	9% 6% 27% 43% 14% 1	630
	11th to 20th	Night	9% 5% 35% 43% 8%	630
	21st to end	Night	5% 4 31% 50% 10%	630
July	1st to 10th	Night	6% 2 22% 51% 18%	615
	11th to 20th	Night	5% 2 22% 55% 17%	612
	21st to end	Night	5% 1 20% 51% 23%	690
August	1st to 10th	Night	7% 2 24% 50% 16%	627
	11th to 20th	Night	5% 3 25% 51% 16%	624
	21st to end	Night	5% 3 20% 55% 17%	693
September	1st to 10th	Night	7% 3 24% 48% 17% 1	630
	11th to 20th	Night	9% 4 24% 45% 18% 1	630
	21st to end	Night	10% 2 28% 46% 14%	624
October	1st to 10th	Night	14% 5% 26% 40% 14% 1	691
	11th to 20th	Night	11% 6% 32% 40% 11%	800
	21st to end	Night	11% 6% 35% 38% 10%	1063
November	1st to 10th	Night	7% 7% 36% 40% 9%	1025
	11th to 20th	Night	6% 11% 41% 36% 6%	1050
	21st to end	Night	8% 8% 35% 40% 8%	1050
December	1st to 10th	Night	8% 10% 44% 32% 5%	1050
	11th to 20th	Night	8% 9% 39% 38% 5%	1050
	21st to end	Night	11% 11% 40% 33% 5%	1155

Page generated at 2026-09-26 02:18:37. Version ac07

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