Badlands National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Badlands National Park 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	8% 6% 2 6% 4 3 4 3 5% 8% 51%	158083
	Night	8% 6% 2 6% 4 4 4 4 6% 7% 49%	150843
Transparency	Day	32% 4 13% 28% 19% 4	152840
	Night	34% 4 13% 27% 18% 4	147098
Seeing	Day	12% 7% 27% 32% 18% 4	18589
	Night	11% 6% 32% 38% 11% 1	28418

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	4 10% 6% 11% 6% 4 3 3 4 7% 42%	4720
	11th to 20th	Day	5% 10% 5% 12% 5% 4 4 3 5% 6% 41%	4740
	21st to end	Day	3 7% 3 10% 6% 5% 5% 3 4 6% 48%	5188
February	1st to 10th	Day	8% 11% 4 8% 6% 4 6% 3 5% 6% 38%	1859
	11th to 20th	Day	6% 11% 4 6% 5% 3 4 3 5% 7% 46%	2049
	21st to end	Day	6% 7% 3 8% 5% 4 4 4 5% 7% 47%	1730
March	1st to 10th	Day	8% 8% 2 5% 4 3 3 3 4 6% 55%	4600
	11th to 20th	Day	7% 6% 1 4 3 3 3 2 6% 8% 57%	4817
	21st to end	Day	15% 10% 3 7% 4 4 4 3 5% 8% 36%	5960
April	1st to 10th	Day	14% 8% 3 5% 3 3 4 3 5% 8% 44%	2520
	11th to 20th	Day	13% 7% 3 6% 4 4 5% 4 5% 7% 42%	2505
	21st to end	Day	15% 7% 3 5% 4 4 4 4 5% 8% 42%	2730
May	1st to 10th	Day	10% 6% 2 5% 4 4 4 3 5% 7% 49%	7655
	11th to 20th	Day	14% 6% 2 5% 3 3 4 3 5% 7% 48%	8035
	21st to end	Day	16% 5% 2 6% 3 3 4 3 5% 7% 45%	9026
June	1st to 10th	Day	8% 4 1 4 3 4 4 4 6% 9% 52%	2940
	11th to 20th	Day	8% 3 2 4 3 4 4 4 7% 8% 53%	2940
	21st to end	Day	6% 3 1 3 3 3 3 4 6% 7% 59%	2940
July	1st to 10th	Day	5% 4 1 5% 4 4 5% 4 6% 9% 53%	8249
	11th to 20th	Day	6% 3 1 4 2 3 3 3 5% 7% 64%	8250
	21st to end	Day	7% 4 1 4 3 4 4 4 7% 10% 53%	8957
August	1st to 10th	Day	5% 3 2 4 3 3 4 3 6% 9% 57%	7975
	11th to 20th	Day	7% 4 2 5% 3 3 5% 3 6% 9% 52%	7485
	21st to end	Day	7% 4 1 4 3 3 4 3 6% 10% 54%	7751
September	1st to 10th	Day	6% 3 1 4 3 3 2 3 3 7% 64%	2520
	11th to 20th	Day	9% 4 1 4 2 3 3 2 4 7% 60%	2363
	21st to end	Day	10% 3 1 3 2 3 3 3 4 7% 61%	2288
October	1st to 10th	Day	7% 4 1 3 2 2 2 2 3 4 70%	3590
	11th to 20th	Day	9% 4 2 5% 2 2 3 2 4 7% 59%	3071
	21st to end	Day	11% 7% 2 5% 4 4 4 3 5% 7% 48%	3190
November	1st to 10th	Day	7% 6% 2 5% 3 5% 4 4 6% 6% 54%	1853
	11th to 20th	Day	6% 6% 2 7% 4 4 3 4 4 7% 54%	1890
	21st to end	Day	4 9% 3 6% 4 3 3 4 6% 8% 50%	1799
December	1st to 10th	Day	4 8% 4 8% 5% 4 4 3 6% 8% 46%	2700
	11th to 20th	Day	3 7% 3 7% 4 4 4 3 6% 7% 52%	3106
	21st to end	Day	9% 12% 2 6% 4 4 4 2 4 6% 47%	4092
January	1st to 10th	Night	7% 11% 4 11% 6% 4 4 3 5% 6% 40%	8201
	11th to 20th	Night	3 8% 3 12% 6% 5% 5% 4 6% 7% 42%	8250
	21st to end	Night	2 6% 4 9% 5% 4 4 3 5% 6% 50%	9026
February	1st to 10th	Night	9% 11% 4 8% 5% 4 4 4 5% 6% 39%	2775
	11th to 20th	Night	5% 9% 4 8% 5% 5% 5% 5% 6% 5% 42%	2458
	21st to end	Night	7% 8% 2 6% 6% 4 4 4 5% 7% 49%	2076
March	1st to 10th	Night	10% 7% 3 5% 4 3 4 3 4 6% 50%	5494
	11th to 20th	Night	7% 6% 2 4 3 3 3 4 5% 9% 53%	5374
	21st to end	Night	14% 10% 3 8% 5% 5% 5% 4 6% 7% 34%	5215
April	1st to 10th	Night	13% 8% 3 6% 4 3 5% 4 4 6% 43%	2100
	11th to 20th	Night	14% 6% 2 6% 5% 4 3 4 5% 6% 43%	2062
	21st to end	Night	15% 8% 2 5% 3 4 4 4 5% 8% 42%	1890
May	1st to 10th	Night	9% 5% 2 5% 5% 5% 5% 5% 7% 8% 46%	5292
	11th to 20th	Night	11% 5% 2 5% 3 3 4 3 5% 8% 51%	4853
	21st to end	Night	18% 6% 2 5% 4 4 4 4 5% 7% 43%	5181
June	1st to 10th	Night	8% 5% 2 4 3 4 4 4 7% 9% 52%	1680
	11th to 20th	Night	11% 3 2 4 5% 4 4 4 7% 7% 48%	1680
	21st to end	Night	7% 3 2 4 4 4 4 4 6% 8% 54%	1680
July	1st to 10th	Night	5% 3 1 5% 4 4 6% 5% 7% 9% 53%	4740
	11th to 20th	Night	6% 3 1 4 3 3 4 3 5% 8% 62%	4740
	21st to end	Night	6% 5% 2 5% 4 4 5% 4 7% 9% 49%	5152
August	1st to 10th	Night	5% 3 2 4 3 3 4 4 6% 9% 56%	4846
	11th to 20th	Night	7% 4 2 5% 4 4 4 4 6% 9% 50%	5354
	21st to end	Night	7% 4 2 6% 4 4 5% 4 6% 9% 49%	6465
September	1st to 10th	Night	7% 3 1 4 3 3 3 3 4 6% 63%	2100
	11th to 20th	Night	9% 3 2 4 3 3 4 3 6% 8% 56%	2257
	21st to end	Night	10% 4 1 3 3 2 3 2 3 6% 61%	2288
October	1st to 10th	Night	8% 3 1 3 2 2 2 2 3 4 70%	3590
	11th to 20th	Night	8% 4 1 4 2 2 4 3 5% 7% 59%	4041
	21st to end	Night	10% 6% 2 4 3 3 4 4 5% 7% 52%	4610
November	1st to 10th	Night	7% 6% 2 6% 4 4 4 4 6% 8% 49%	2665
	11th to 20th	Night	6% 8% 2 7% 5% 3 4 3 5% 6% 51%	2730
	21st to end	Night	6% 7% 2 5% 4 3 4 4 6% 7% 52%	2819
December	1st to 10th	Night	4 7% 2 6% 4 4 5% 4 7% 6% 50%	4710
	11th to 20th	Night	4 7% 2 7% 5% 5% 5% 4 6% 8% 46%	5321
	21st to end	Night	10% 10% 3 8% 4 4 4 4 6% 7% 42%	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	44% 2 15% 29% 9%	4723
	11th to 20th	Day	44% 4 14% 22% 14% 2	4740
	21st to end	Day	38% 3 16% 28% 13% 2	5188
February	1st to 10th	Day	47% 3 13% 22% 13% 2	1859
	11th to 20th	Day	39% 3 16% 22% 15% 4	2059
	21st to end	Day	37% 3 14% 29% 14% 3	1730
March	1st to 10th	Day	33% 2 8% 30% 24% 4	4600
	11th to 20th	Day	28% 2 13% 37% 20% 1	4817
	21st to end	Day	47% 4 17% 21% 10%	5960
April	1st to 10th	Day	40% 4 14% 29% 11% 3	2520
	11th to 20th	Day	41% 4 12% 23% 17% 3	2508
	21st to end	Day	41% 3 15% 29% 11% 1	2730
May	1st to 10th	Day	34% 4 10% 31% 20% 2	7655
	11th to 20th	Day	37% 3 11% 26% 20% 3	8039
	21st to end	Day	38% 4 13% 25% 18% 2	9027
June	1st to 10th	Day	29% 4 19% 29% 16% 3	2940
	11th to 20th	Day	27% 4 19% 28% 19% 4	2940
	21st to end	Day	23% 3 12% 32% 23% 6%	2940
July	1st to 10th	Day	26% 6% 14% 30% 22% 2	8181
	11th to 20th	Day	20% 4 10% 27% 24% 15%	8175
	21st to end	Day	26% 6% 13% 27% 22% 6%	8759
August	1st to 10th	Day	23% 4 14% 23% 25% 10%	6312
	11th to 20th	Day	34% 7% 17% 25% 15% 3	5900
	21st to end	Day	19% 5% 20% 28% 20% 9%	6078
September	1st to 10th	Day	22% 2 8% 30% 28% 10%	2520
	11th to 20th	Day	27% 3 10% 31% 23% 8%	2363
	21st to end	Day	25% 2 8% 33% 28% 4	2288
October	1st to 10th	Day	20% 2 8% 22% 32% 16%	3590
	11th to 20th	Day	28% 2 11% 36% 20% 3	3071
	21st to end	Day	36% 3 11% 31% 16% 4	3190
November	1st to 10th	Day	30% 3 13% 28% 21% 5%	1853
	11th to 20th	Day	32% 3 11% 28% 22% 5%	1890
	21st to end	Day	33% 3 15% 32% 14% 4	1799
December	1st to 10th	Day	37% 3 15% 29% 14% 1	2700
	11th to 20th	Day	32% 4 19% 32% 13% 1	3104
	21st to end	Day	41% 2 8% 38% 11% 1	4092
January	1st to 10th	Night	46% 3 13% 28% 9% 1	8202
	11th to 20th	Night	41% 4 16% 24% 14% 1	8250
	21st to end	Night	35% 3 14% 29% 18% 1	9026
February	1st to 10th	Night	46% 3 14% 23% 13% 1	2775
	11th to 20th	Night	42% 4 11% 25% 15% 3	2458
	21st to end	Night	35% 3 14% 29% 15% 4	2076
March	1st to 10th	Night	37% 2 7% 28% 22% 3	5494
	11th to 20th	Night	29% 2 13% 33% 21% 2	5374
	21st to end	Night	48% 3 16% 22% 10% 1	5215
April	1st to 10th	Night	42% 5% 13% 25% 13% 3	2100
	11th to 20th	Night	40% 3 12% 22% 20% 3	2062
	21st to end	Night	42% 3 13% 27% 13% 1	1890
May	1st to 10th	Night	34% 5% 10% 28% 21% 2	5293
	11th to 20th	Night	33% 3 12% 29% 20% 3	4854
	21st to end	Night	41% 4 12% 26% 16% 1	5182
June	1st to 10th	Night	29% 4 19% 28% 18% 2	1680
	11th to 20th	Night	33% 4 19% 24% 17% 3	1680
	21st to end	Night	27% 4 13% 30% 19% 6%	1680
July	1st to 10th	Night	26% 5% 19% 28% 20% 2	4700
	11th to 20th	Night	21% 4 13% 26% 23% 14%	4692
	21st to end	Night	30% 6% 15% 27% 17% 4	5038
August	1st to 10th	Night	23% 5% 14% 24% 25% 10%	3833
	11th to 20th	Night	34% 8% 21% 21% 14% 3	4215
	21st to end	Night	24% 6% 20% 25% 18% 6%	5069
September	1st to 10th	Night	22% 3 9% 29% 28% 9%	2100
	11th to 20th	Night	26% 4 12% 27% 25% 6%	2257
	21st to end	Night	27% 3 7% 31% 26% 7%	2288
October	1st to 10th	Night	21% 2 6% 20% 32% 18%	3590
	11th to 20th	Night	25% 4 10% 36% 22% 4	4041
	21st to end	Night	32% 3 12% 27% 20% 6%	4610
November	1st to 10th	Night	34% 3 12% 27% 20% 6%	2665
	11th to 20th	Night	35% 2 11% 27% 20% 5%	2730
	21st to end	Night	31% 4 14% 31% 18% 3	2819
December	1st to 10th	Night	32% 4 18% 29% 15% 1	4710
	11th to 20th	Night	35% 4 16% 31% 12% 2	5322
	21st to end	Night	42% 3 9% 32% 12% 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	8% 6% 32% 31% 18% 5%	330
	11th to 20th	Day	13% 10% 35% 28% 13% 2	330
	21st to end	Day	10% 11% 40% 28% 9% 2	363
February	1st to 10th	Day	12% 9% 38% 35% 5%	330
	11th to 20th	Day	12% 9% 39% 30% 9%	330
	21st to end	Day	13% 10% 42% 26% 8% 1	273
March	1st to 10th	Day	15% 6% 35% 29% 12% 3	330
	11th to 20th	Day	11% 10% 35% 29% 12% 3	330
	21st to end	Day	19% 11% 27% 27% 13% 3	531
April	1st to 10th	Day	20% 12% 33% 26% 8% 1	540
	11th to 20th	Day	20% 13% 30% 26% 10%	546
	21st to end	Day	20% 8% 26% 30% 15% 1	750
May	1st to 10th	Day	17% 8% 25% 30% 16% 4	753
	11th to 20th	Day	21% 5% 20% 32% 17% 6%	775
	21st to end	Day	19% 6% 26% 30% 15% 5%	844
June	1st to 10th	Day	7% 6% 24% 33% 21% 9%	780
	11th to 20th	Day	11% 6% 30% 35% 15% 3	780
	21st to end	Day	8% 7% 24% 35% 23% 3	780
July	1st to 10th	Day	6% 2 19% 40% 26% 6%	771
	11th to 20th	Day	7% 2 22% 42% 23% 4	768
	21st to end	Day	5% 3 19% 40% 28% 5%	849
August	1st to 10th	Day	6% 3 20% 40% 27% 5%	776
	11th to 20th	Day	7% 4 19% 36% 25% 8%	730
	21st to end	Day	7% 5% 20% 35% 23% 10%	627
September	1st to 10th	Day	7% 5% 23% 34% 25% 7%	570
	11th to 20th	Day	10% 4 21% 30% 25% 10%	413
	21st to end	Day	14% 6% 22% 30% 21% 7%	354
October	1st to 10th	Day	15% 7% 21% 28% 19% 10%	330
	11th to 20th	Day	15% 10% 33% 23% 15% 4	330
	21st to end	Day	16% 10% 32% 25% 15% 2	363
November	1st to 10th	Day	11% 9% 34% 31% 11% 3	330
	11th to 20th	Day	13% 12% 31% 29% 13% 2	330
	21st to end	Day	11% 7% 32% 33% 14% 3	330
December	1st to 10th	Day	13% 10% 35% 32% 8% 1	330
	11th to 20th	Day	11% 9% 41% 30% 9% 1	330
	21st to end	Day	15% 10% 34% 28% 11% 2	363
January	1st to 10th	Night	8% 8% 35% 35% 12% 2	1050
	11th to 20th	Night	10% 12% 36% 33% 9% 1	1050
	21st to end	Night	11% 8% 38% 35% 8%	1155
February	1st to 10th	Night	15% 9% 37% 33% 6%	945
	11th to 20th	Night	10% 6% 41% 37% 7%	824
	21st to end	Night	10% 6% 41% 34% 8% 1	692
March	1st to 10th	Night	13% 8% 33% 37% 8% 1	840
	11th to 20th	Night	12% 7% 33% 36% 11% 1	758
	21st to end	Night	17% 8% 31% 34% 9% 1	693
April	1st to 10th	Night	17% 7% 34% 35% 7%	630
	11th to 20th	Night	17% 9% 35% 35% 4	623
	21st to end	Night	19% 8% 27% 35% 10%	630
May	1st to 10th	Night	14% 5% 27% 40% 13% 1	630
	11th to 20th	Night	16% 5% 27% 38% 13%	621
	21st to end	Night	16% 7% 35% 32% 10% 1	683
June	1st to 10th	Night	10% 6% 30% 38% 16% 1	630
	11th to 20th	Night	12% 5% 34% 40% 8% 1	630
	21st to end	Night	8% 3 31% 43% 14%	630
July	1st to 10th	Night	7% 3 26% 45% 18% 1	615
	11th to 20th	Night	5% 1 29% 50% 15%	612
	21st to end	Night	5% 2 26% 52% 14% 1	690
August	1st to 10th	Night	6% 4 24% 49% 17%	627
	11th to 20th	Night	6% 2 24% 51% 16%	624
	21st to end	Night	4 5% 24% 50% 17%	693
September	1st to 10th	Night	8% 1 27% 46% 16% 1	630
	11th to 20th	Night	10% 4 26% 42% 17% 1	630
	21st to end	Night	13% 5% 26% 40% 16% 1	624
October	1st to 10th	Night	16% 5% 26% 37% 15% 1	600
	11th to 20th	Night	13% 7% 31% 36% 12% 1	879
	21st to end	Night	14% 8% 32% 35% 11% 1	1100
November	1st to 10th	Night	10% 5% 36% 40% 10% 1	1025
	11th to 20th	Night	10% 8% 34% 37% 10%	1050
	21st to end	Night	9% 7% 35% 38% 10%	1050
December	1st to 10th	Night	12% 8% 38% 33% 9%	1050
	11th to 20th	Night	9% 7% 37% 36% 10% 1	1050
	21st to end	Night	15% 9% 32% 35% 8%	1155

Page generated at 2026-09-26 02:18:40. Version ac07

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