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 2024-11-02.

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 4 3 4 4 4 6% 8% 54%	101360
	Night	7% 6% 2 5% 4 4 4 4 6% 7% 52%	97824
Transparency	Day	27% 7% 13% 26% 20% 7%	101101
	Night	29% 8% 15% 27% 17% 5%	97673
Seeing	Day	10% 8% 27% 31% 19% 5%	15769
	Night	9% 7% 34% 39% 10%	25720

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	2 6% 4 8% 5% 4 3 3 5% 6% 54%	2538
	11th to 20th	Day	4 8% 4 8% 5% 5% 5% 4 6% 7% 43%	2540
	21st to end	Day	3 5% 2 4 3 3 3 3 5% 7% 63%	2926
February	1st to 10th	Day	5% 10% 3 8% 5% 5% 4 3 6% 7% 45%	1714
	11th to 20th	Day	5% 8% 4 6% 4 4 4 3 6% 7% 48%	1849
	21st to end	Day	5% 7% 3 6% 4 4 4 3 5% 6% 53%	1570
March	1st to 10th	Day	5% 10% 2 5% 4 4 3 3 5% 7% 52%	3130
	11th to 20th	Day	8% 5% 2 3 3 3 4 3 4 6% 59%	3262
	21st to end	Day	9% 7% 3 7% 5% 4 4 4 6% 8% 44%	4165
April	1st to 10th	Day	10% 7% 2 4 4 4 4 4 6% 6% 48%	2280
	11th to 20th	Day	15% 6% 2 6% 4 4 5% 4 5% 8% 42%	2251
	21st to end	Day	12% 6% 2 5% 4 4 4 3 6% 7% 47%	2352
May	1st to 10th	Day	14% 6% 2 5% 3 4 5% 4 5% 7% 45%	4120
	11th to 20th	Day	11% 4 2 4 3 4 5% 4 6% 8% 50%	4357
	21st to end	Day	10% 4 2 5% 3 4 5% 4 6% 8% 48%	4825
June	1st to 10th	Day	6% 3 1 4 4 4 4 5% 6% 9% 54%	2660
	11th to 20th	Day	8% 3 2 4 3 3 4 4 6% 9% 53%	2660
	21st to end	Day	4 2 1 3 3 4 4 4 6% 9% 59%	2660
July	1st to 10th	Day	6% 3 1 3 3 3 4 3 6% 7% 61%	4430
	11th to 20th	Day	3 1 1 2 2 3 4 4 8% 10% 60%	4430
	21st to end	Day	3 2 1 3 3 4 4 4 7% 10% 60%	4802
August	1st to 10th	Day	9% 4 2 4 3 3 4 4 6% 9% 53%	4326
	11th to 20th	Day	4 3 1 5% 3 4 5% 4 6% 7% 58%	3726
	21st to end	Day	4 3 2 4 3 4 5% 4 5% 8% 59%	4180
September	1st to 10th	Day	7% 4 1 3 2 3 3 2 5% 5% 65%	2280
	11th to 20th	Day	7% 2 1 3 2 3 3 3 3 6% 65%	2201
	21st to end	Day	8% 3 1 3 2 2 2 3 5% 6% 65%	2090
October	1st to 10th	Day	11% 5% 1 3 2 2 3 3 5% 6% 59%	2000
	11th to 20th	Day	8% 4 2 3 3 2 3 3 5% 7% 61%	1900
	21st to end	Day	7% 5% 1 4 3 3 3 3 5% 6% 59%	1896
November	1st to 10th	Day	3 6% 2 4 3 3 3 3 5% 8% 59%	1682
	11th to 20th	Day	4 5% 2 4 3 3 3 3 7% 7% 59%	1710
	21st to end	Day	5% 6% 2 4 3 3 3 3 4 7% 60%	1608
December	1st to 10th	Day	4 6% 3 6% 4 3 4 4 6% 7% 53%	1520
	11th to 20th	Day	4 6% 1 5% 3 4 3 3 6% 8% 57%	1926
	21st to end	Day	9% 10% 3 5% 4 3 4 3 4 7% 47%	2794
January	1st to 10th	Night	3 8% 3 6% 4 4 4 3 6% 7% 53%	4417
	11th to 20th	Night	2 7% 4 7% 4 4 5% 4 6% 8% 49%	4430
	21st to end	Night	3 5% 2 6% 4 4 4 4 5% 7% 57%	4768
February	1st to 10th	Night	4 10% 3 7% 4 5% 4 4 6% 6% 46%	2464
	11th to 20th	Night	6% 8% 3 7% 5% 4 5% 4 6% 7% 46%	2218
	21st to end	Night	4 8% 3 8% 4 4 4 3 6% 6% 51%	1884
March	1st to 10th	Night	5% 13% 3 5% 4 3 3 3 4 5% 51%	3734
	11th to 20th	Night	9% 7% 2 6% 4 3 3 3 4 5% 56%	3707
	21st to end	Night	9% 7% 2 7% 4 4 4 4 6% 8% 44%	3477
April	1st to 10th	Night	13% 7% 2 5% 3 4 3 3 5% 7% 48%	1900
	11th to 20th	Night	11% 6% 2 6% 5% 4 4 3 5% 6% 47%	1877
	21st to end	Night	13% 8% 3 6% 4 4 4 4 5% 6% 43%	1825
May	1st to 10th	Night	14% 8% 3 7% 4 4 4 3 6% 7% 41%	2850
	11th to 20th	Night	11% 4 1 4 2 3 4 4 7% 8% 51%	2533
	21st to end	Night	14% 3 2 5% 4 4 5% 4 6% 8% 46%	2762
June	1st to 10th	Night	8% 5% 1 4 2 3 5% 3 6% 9% 52%	1520
	11th to 20th	Night	8% 3 1 4 4 4 4 4 6% 10% 52%	1520
	21st to end	Night	4 2 1 3 4 5% 4 4 7% 10% 55%	1520
July	1st to 10th	Night	6% 4 2 5% 5% 5% 5% 4 6% 7% 52%	2540
	11th to 20th	Night	3 2 1 3 3 3 4 4 8% 11% 57%	2540
	21st to end	Night	3 2 2 4 4 4 5% 4 7% 10% 54%	2761
August	1st to 10th	Night	12% 4 2 4 4 4 5% 4 6% 9% 45%	2609
	11th to 20th	Night	4 3 2 4 4 4 5% 5% 7% 10% 51%	3113
	21st to end	Night	4 3 1 5% 4 5% 6% 4 7% 9% 53%	3487
September	1st to 10th	Night	7% 4 2 4 3 3 4 3 5% 7% 59%	1900
	11th to 20th	Night	8% 3 1 4 3 3 3 3 4 7% 61%	1978
	21st to end	Night	8% 3 1 4 3 3 4 3 4 4 62%	2090
October	1st to 10th	Night	12% 4 1 4 3 3 3 3 4 6% 59%	2176
	11th to 20th	Night	9% 4 1 3 3 3 4 3 5% 5% 62%	2280
	21st to end	Night	8% 6% 2 4 2 3 4 3 5% 7% 56%	2682
November	1st to 10th	Night	6% 4 2 5% 3 3 4 2 5% 8% 58%	2419
	11th to 20th	Night	5% 6% 1 5% 3 4 3 4 6% 7% 57%	2470
	21st to end	Night	5% 7% 2 5% 3 3 3 3 5% 6% 58%	2569
December	1st to 10th	Night	5% 7% 2 6% 4 3 4 4 6% 8% 53%	2660
	11th to 20th	Night	4 5% 2 4 3 4 4 3 5% 8% 58%	3271
	21st to end	Night	10% 9% 3 6% 3 3 4 3 5% 7% 47%	4873

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	30% 6% 14% 29% 20% 1	2539
	11th to 20th	Day	37% 9% 18% 20% 15% 1	2540
	21st to end	Day	21% 6% 21% 34% 14% 3	2926
February	1st to 10th	Day	39% 7% 16% 22% 14% 2	1714
	11th to 20th	Day	34% 7% 12% 26% 17% 4	1859
	21st to end	Day	31% 7% 14% 27% 17% 5%	1570
March	1st to 10th	Day	30% 6% 9% 28% 23% 3	3130
	11th to 20th	Day	26% 6% 18% 32% 16% 2	3262
	21st to end	Day	35% 11% 15% 28% 9% 1	4165
April	1st to 10th	Day	33% 7% 16% 25% 14% 5%	2280
	11th to 20th	Day	38% 8% 13% 21% 16% 4	2254
	21st to end	Day	34% 7% 13% 28% 16% 2	2352
May	1st to 10th	Day	34% 11% 14% 23% 13% 5%	4120
	11th to 20th	Day	28% 10% 15% 30% 15% 3	4361
	21st to end	Day	30% 10% 17% 27% 13% 3	4825
June	1st to 10th	Day	23% 11% 18% 28% 16% 4	2660
	11th to 20th	Day	26% 8% 12% 27% 20% 7%	2660
	21st to end	Day	19% 7% 12% 26% 26% 9%	2660
July	1st to 10th	Day	22% 5% 8% 21% 29% 14%	4361
	11th to 20th	Day	16% 6% 12% 28% 25% 14%	4355
	21st to end	Day	18% 6% 12% 21% 23% 20%	4651
August	1st to 10th	Day	26% 6% 15% 26% 19% 8%	4311
	11th to 20th	Day	25% 7% 11% 21% 25% 11%	3762
	21st to end	Day	22% 6% 11% 19% 25% 18%	4179
September	1st to 10th	Day	21% 4 8% 21% 30% 16%	2280
	11th to 20th	Day	20% 4 9% 25% 29% 14%	2201
	21st to end	Day	20% 4 9% 25% 34% 8%	2090
October	1st to 10th	Day	26% 5% 11% 22% 27% 8%	2000
	11th to 20th	Day	24% 5% 11% 29% 23% 8%	1900
	21st to end	Day	25% 6% 14% 29% 21% 6%	1896
November	1st to 10th	Day	23% 5% 16% 28% 20% 8%	1682
	11th to 20th	Day	22% 5% 15% 30% 24% 4	1710
	21st to end	Day	25% 4 14% 29% 24% 4	1608
December	1st to 10th	Day	29% 7% 16% 27% 18% 3	1520
	11th to 20th	Day	24% 6% 15% 36% 18% 1	1924
	21st to end	Day	36% 6% 12% 30% 14% 2	2794
January	1st to 10th	Night	29% 7% 12% 36% 14% 1	4417
	11th to 20th	Night	30% 8% 21% 22% 17% 3	4430
	21st to end	Night	25% 8% 21% 32% 13% 1	4768
February	1st to 10th	Night	36% 8% 16% 26% 13% 2	2464
	11th to 20th	Night	34% 8% 14% 25% 15% 3	2218
	21st to end	Night	33% 6% 12% 28% 18% 4	1884
March	1st to 10th	Night	32% 8% 9% 24% 24% 4	3734
	11th to 20th	Night	29% 6% 15% 29% 18% 2	3707
	21st to end	Night	34% 13% 23% 22% 8% 1	3477
April	1st to 10th	Night	35% 7% 14% 23% 17% 5%	1900
	11th to 20th	Night	35% 8% 14% 24% 16% 3	1877
	21st to end	Night	39% 8% 11% 27% 14% 1	1825
May	1st to 10th	Night	38% 11% 15% 20% 14% 2	2850
	11th to 20th	Night	26% 11% 19% 32% 8% 4	2534
	21st to end	Night	32% 12% 18% 27% 8% 3	2762
June	1st to 10th	Night	26% 10% 24% 25% 12% 3	1520
	11th to 20th	Night	26% 9% 18% 24% 17% 6%	1520
	21st to end	Night	22% 8% 15% 26% 23% 6%	1520
July	1st to 10th	Night	28% 7% 11% 24% 21% 8%	2500
	11th to 20th	Night	19% 6% 20% 26% 21% 8%	2492
	21st to end	Night	23% 7% 16% 23% 20% 11%	2674
August	1st to 10th	Night	34% 8% 17% 21% 17% 3	2601
	11th to 20th	Night	26% 9% 16% 23% 20% 7%	3143
	21st to end	Night	26% 7% 15% 19% 23% 11%	3487
September	1st to 10th	Night	25% 5% 9% 23% 26% 12%	1900
	11th to 20th	Night	22% 7% 10% 26% 24% 12%	1978
	21st to end	Night	24% 5% 8% 27% 25% 10%	2090
October	1st to 10th	Night	27% 5% 13% 22% 25% 8%	2176
	11th to 20th	Night	24% 5% 12% 29% 21% 9%	2280
	21st to end	Night	28% 6% 13% 25% 20% 8%	2682
November	1st to 10th	Night	25% 6% 13% 27% 24% 6%	2419
	11th to 20th	Night	25% 6% 12% 30% 21% 6%	2470
	21st to end	Night	27% 6% 11% 30% 21% 5%	2569
December	1st to 10th	Night	29% 6% 15% 29% 18% 4	2660
	11th to 20th	Night	25% 5% 15% 37% 17% 1	3272
	21st to end	Night	35% 7% 13% 30% 13% 2	4873

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% 6% 33% 32% 16% 3	270
	11th to 20th	Day	10% 13% 34% 33% 9%	270
	21st to end	Day	8% 9% 47% 27% 7% 2	297
February	1st to 10th	Day	8% 16% 49% 22% 5%	270
	11th to 20th	Day	7% 16% 46% 24% 6% 2	270
	21st to end	Day	14% 16% 37% 29% 4	225
March	1st to 10th	Day	7% 15% 35% 30% 14%	270
	11th to 20th	Day	11% 11% 35% 28% 12% 3	323
	21st to end	Day	13% 15% 35% 26% 9% 2	506
April	1st to 10th	Day	17% 16% 35% 22% 9% 1	460
	11th to 20th	Day	20% 17% 31% 23% 8% 2	452
	21st to end	Day	14% 12% 30% 27% 14% 3	532
May	1st to 10th	Day	17% 13% 25% 29% 14% 3	653
	11th to 20th	Day	17% 7% 23% 32% 17% 5%	675
	21st to end	Day	13% 9% 26% 30% 18% 4	734
June	1st to 10th	Day	6% 4 22% 35% 25% 8%	680
	11th to 20th	Day	9% 7% 30% 35% 17% 3	680
	21st to end	Day	6% 5% 25% 34% 26% 4	680
July	1st to 10th	Day	7% 2 18% 37% 30% 6%	671
	11th to 20th	Day	5% 2 18% 37% 32% 6%	668
	21st to end	Day	6% 1 15% 36% 36% 6%	739
August	1st to 10th	Day	6% 2 18% 38% 31% 5%	647
	11th to 20th	Day	5% 4 20% 36% 24% 11%	477
	21st to end	Day	4 3 23% 33% 26% 11%	539
September	1st to 10th	Day	5% 5% 20% 32% 28% 11%	490
	11th to 20th	Day	7% 3 19% 32% 28% 11%	411
	21st to end	Day	7% 9% 21% 32% 19% 11%	300
October	1st to 10th	Day	13% 6% 23% 23% 22% 12%	300
	11th to 20th	Day	8% 12% 29% 28% 17% 7%	300
	21st to end	Day	10% 11% 33% 28% 15% 3	330
November	1st to 10th	Day	6% 10% 32% 34% 14% 5%	273
	11th to 20th	Day	6% 12% 33% 33% 15% 1	270
	21st to end	Day	13% 7% 33% 33% 13% 2	270
December	1st to 10th	Day	9% 12% 38% 30% 10% 1	270
	11th to 20th	Day	9% 13% 42% 26% 10%	270
	21st to end	Day	14% 11% 37% 29% 8% 1	297
January	1st to 10th	Night	7% 10% 38% 34% 10%	950
	11th to 20th	Night	7% 13% 42% 31% 6% 1	950
	21st to end	Night	8% 8% 45% 33% 6%	979
February	1st to 10th	Night	8% 9% 49% 29% 5%	760
	11th to 20th	Night	9% 9% 43% 34% 5%	744
	21st to end	Night	8% 12% 45% 31% 4	628
March	1st to 10th	Night	10% 10% 40% 35% 6%	760
	11th to 20th	Night	12% 6% 35% 40% 7%	760
	21st to end	Night	14% 11% 36% 34% 5%	627
April	1st to 10th	Night	16% 11% 36% 32% 5%	570
	11th to 20th	Night	12% 10% 40% 33% 4	563
	21st to end	Night	16% 9% 31% 35% 9%	570
May	1st to 10th	Night	18% 8% 30% 34% 10% 1	570
	11th to 20th	Night	16% 6% 27% 40% 11%	561
	21st to end	Night	13% 6% 31% 39% 12%	617
June	1st to 10th	Night	9% 6% 26% 44% 15% 1	570
	11th to 20th	Night	9% 5% 33% 45% 8%	570
	21st to end	Night	4 3 29% 52% 11%	570
July	1st to 10th	Night	7% 2 21% 50% 19% 1	555
	11th to 20th	Night	4 2 21% 56% 16%	552
	21st to end	Night	4 1 18% 53% 23%	624
August	1st to 10th	Night	8% 2 22% 51% 18%	567
	11th to 20th	Night	5% 3 25% 52% 16%	564
	21st to end	Night	4 3 20% 55% 18%	627
September	1st to 10th	Night	8% 3 23% 47% 17% 1	570
	11th to 20th	Night	8% 3 23% 46% 19% 1	570
	21st to end	Night	10% 2 28% 46% 13% 1	570
October	1st to 10th	Night	14% 5% 27% 39% 14% 1	656
	11th to 20th	Night	11% 5% 31% 41% 12%	760
	21st to end	Night	11% 6% 34% 38% 10%	1010
November	1st to 10th	Night	7% 6% 37% 41% 10%	931
	11th to 20th	Night	6% 10% 41% 36% 6%	950
	21st to end	Night	8% 8% 35% 39% 8%	950
December	1st to 10th	Night	8% 10% 45% 32% 5%	950
	11th to 20th	Night	8% 7% 40% 39% 5%	950
	21st to end	Night	12% 11% 40% 32% 6%	1045

Page generated at 2024-10-29 23:22:56. Version ac07

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