Copper Breaks State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Copper Breaks State Park clear sky chart from 2005-11-06 to 2025-09-04.

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% 4 2 4 3 3 3 3 5% 6% 60%	125969
	Night	6% 4 2 4 3 3 3 3 5% 7% 61%	123083
Transparency	Day	25% 4 8% 22% 27% 13%	129752
	Night	23% 4 8% 22% 27% 16%	127352
Seeing	Day	9% 6% 24% 33% 23% 6%	16405
	Night	8% 7% 32% 38% 14% 1	26239

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	7% 5% 2 6% 4 4 3 2 4 5% 58%	4077
	11th to 20th	Day	5% 5% 1 2 2 2 2 2 3 4 72%	4080
	21st to end	Day	12% 5% 2 4 3 3 3 3 4 7% 55%	4744
February	1st to 10th	Day	8% 5% 2 6% 3 2 3 2 3 6% 59%	2000
	11th to 20th	Day	9% 6% 2 6% 3 3 3 3 4 5% 56%	1949
	21st to end	Day	10% 8% 2 4 3 2 3 2 4 4 59%	1650
March	1st to 10th	Day	10% 4 2 4 3 3 3 3 4 6% 59%	4577
	11th to 20th	Day	8% 5% 2 4 3 3 3 3 4 5% 60%	4980
	21st to end	Day	5% 6% 2 4 3 3 4 3 5% 8% 56%	5462
April	1st to 10th	Day	8% 3 1 3 3 4 3 2 4 6% 62%	2290
	11th to 20th	Day	12% 5% 2 5% 3 3 3 3 4 5% 56%	2374
	21st to end	Day	9% 4 1 4 4 3 3 4 5% 6% 58%	2530
May	1st to 10th	Day	15% 5% 2 5% 3 3 3 3 4 6% 51%	5862
	11th to 20th	Day	10% 4 2 4 3 3 3 3 3 5% 60%	5862
	21st to end	Day	9% 5% 2 6% 4 4 4 3 5% 6% 52%	6434
June	1st to 10th	Day	5% 3 2 5% 4 4 4 3 6% 7% 57%	2600
	11th to 20th	Day	6% 2 1 4 4 4 4 3 6% 7% 60%	2600
	21st to end	Day	4 3 2 3 3 3 4 3 6% 6% 62%	2600
July	1st to 10th	Day	9% 5% 2 6% 5% 5% 5% 4 6% 7% 45%	5900
	11th to 20th	Day	3 2 1 4 4 4 4 3 5% 8% 62%	5900
	21st to end	Day	2 2 1 3 3 3 3 3 5% 8% 68%	6422
August	1st to 10th	Day	3 2 1 3 3 3 3 4 4 7% 67%	4215
	11th to 20th	Day	3 2 1 3 3 3 4 3 5% 8% 65%	3846
	21st to end	Day	4 3 1 3 3 3 3 3 5% 6% 66%	4312
September	1st to 10th	Day	10% 3 1 4 3 3 3 3 5% 6% 59%	2178
	11th to 20th	Day	10% 4 2 6% 5% 4 3 4 5% 7% 51%	2090
	21st to end	Day	8% 4 1 4 3 3 2 3 5% 5% 62%	2090
October	1st to 10th	Day	6% 3 1 3 3 3 4 3 5% 5% 64%	2090
	11th to 20th	Day	9% 3 1 4 3 2 2 3 3 4 67%	2011
	21st to end	Day	10% 4 2 3 2 2 2 2 3 4 66%	2062
November	1st to 10th	Day	8% 3 1 3 3 2 3 2 4 6% 63%	1763
	11th to 20th	Day	5% 3 1 2 2 2 2 3 4 6% 69%	1800
	21st to end	Day	10% 5% 2 3 3 2 3 2 4 5% 62%	1800
December	1st to 10th	Day	5% 5% 2 6% 3 2 3 3 4 6% 61%	2940
	11th to 20th	Day	6% 3 1 3 3 3 4 3 4 4 65%	3391
	21st to end	Day	10% 7% 2 5% 3 3 3 2 4 4 57%	4488
January	1st to 10th	Night	9% 7% 2 5% 3 2 3 3 4 5% 57%	5888
	11th to 20th	Night	3 3 2 3 2 2 3 2 3 5% 72%	5900
	21st to end	Night	11% 8% 2 4 3 2 2 3 4 5% 55%	6278
February	1st to 10th	Night	9% 5% 2 5% 3 2 3 3 4 5% 59%	2400
	11th to 20th	Night	9% 6% 1 4 3 2 3 3 5% 7% 57%	2338
	21st to end	Night	7% 4 3 4 3 4 3 3 5% 6% 58%	1980
March	1st to 10th	Night	7% 5% 2 5% 3 3 3 3 4 5% 60%	5292
	11th to 20th	Night	7% 3 1 3 2 3 3 2 4 6% 66%	4980
	21st to end	Night	4 5% 2 5% 3 3 4 3 5% 7% 59%	5467
April	1st to 10th	Night	7% 5% 1 4 3 3 4 3 4 6% 61%	2105
	11th to 20th	Night	11% 3 1 4 2 3 3 3 5% 7% 58%	1977
	21st to end	Night	8% 4 1 4 3 3 2 3 6% 6% 59%	1869
May	1st to 10th	Night	13% 5% 1 4 2 3 3 3 4 5% 55%	4053
	11th to 20th	Night	7% 3 1 4 3 3 4 3 5% 7% 59%	4053
	21st to end	Night	10% 5% 2 4 3 3 4 3 5% 6% 55%	4443
June	1st to 10th	Night	5% 3 1 3 3 4 3 4 7% 11% 56%	1800
	11th to 20th	Night	3 3 1 3 3 3 4 4 7% 11% 59%	1800
	21st to end	Night	3 2 1 4 3 3 4 3 6% 7% 62%	1800
July	1st to 10th	Night	6% 5% 2 6% 5% 5% 4 4 6% 8% 48%	4078
	11th to 20th	Night	3 2 1 3 2 3 3 3 6% 11% 64%	4077
	21st to end	Night	1 2 1 4 3 3 4 4 6% 8% 65%	4449
August	1st to 10th	Night	1 1 1 2 2 3 3 3 5% 9% 70%	2940
	11th to 20th	Night	3 2 1 3 2 3 4 4 7% 11% 60%	3213
	21st to end	Night	3 2 1 3 2 2 3 3 6% 10% 64%	3597
September	1st to 10th	Night	8% 4 2 5% 2 4 4 4 4 7% 58%	2066
	11th to 20th	Night	9% 5% 2 5% 4 3 3 4 5% 9% 51%	2090
	21st to end	Night	6% 3 1 4 3 4 3 4 4 6% 62%	2090
October	1st to 10th	Night	6% 4 1 4 3 2 3 3 4 5% 65%	2090
	11th to 20th	Night	7% 3 2 4 2 2 2 2 3 4 69%	2147
	21st to end	Night	7% 2 1 3 2 2 2 2 3 5% 69%	2532
November	1st to 10th	Night	8% 3 1 3 2 2 2 2 4 5% 68%	2535
	11th to 20th	Night	5% 3 1 3 2 2 3 3 4 6% 68%	2600
	21st to end	Night	8% 4 1 3 4 3 3 3 4 6% 63%	2600
December	1st to 10th	Night	7% 4 2 3 2 3 3 3 4 6% 64%	4250
	11th to 20th	Night	5% 3 1 4 3 3 3 3 4 6% 66%	4816
	21st to end	Night	7% 6% 2 5% 3 3 3 3 4 5% 58%	6490

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	29% 3 6% 30% 23% 9%	4078
	11th to 20th	Day	18% 2 5% 22% 41% 12%	4080
	21st to end	Day	31% 3 8% 19% 24% 15%	4744
February	1st to 10th	Day	27% 3 8% 21% 30% 11%	2000
	11th to 20th	Day	31% 3 6% 23% 23% 13%	1959
	21st to end	Day	30% 3 4 16% 27% 20%	1650
March	1st to 10th	Day	27% 3 5% 10% 26% 30%	4577
	11th to 20th	Day	27% 4 7% 15% 24% 24%	4980
	21st to end	Day	26% 4 9% 26% 26% 9%	5464
April	1st to 10th	Day	25% 3 8% 21% 26% 17%	2290
	11th to 20th	Day	31% 5% 7% 17% 24% 16%	2374
	21st to end	Day	27% 5% 10% 23% 27% 9%	2530
May	1st to 10th	Day	33% 5% 9% 22% 18% 12%	5900
	11th to 20th	Day	27% 5% 8% 16% 25% 19%	5866
	21st to end	Day	32% 7% 10% 22% 16% 13%	6447
June	1st to 10th	Day	25% 6% 13% 29% 19% 7%	2600
	11th to 20th	Day	21% 6% 12% 24% 28% 9%	2600
	21st to end	Day	22% 5% 12% 26% 27% 9%	2600
July	1st to 10th	Day	37% 6% 9% 21% 23% 5%	5836
	11th to 20th	Day	21% 4 11% 27% 30% 7%	5831
	21st to end	Day	14% 4 14% 32% 30% 6%	6240
August	1st to 10th	Day	16% 4 9% 23% 31% 16%	4201
	11th to 20th	Day	17% 5% 12% 27% 28% 11%	3882
	21st to end	Day	19% 6% 14% 26% 29% 6%	4311
September	1st to 10th	Day	27% 4 9% 22% 25% 12%	2178
	11th to 20th	Day	33% 5% 9% 19% 24% 9%	2090
	21st to end	Day	24% 4 7% 20% 32% 13%	2090
October	1st to 10th	Day	13% 4 6% 15% 35% 28%	3480
	11th to 20th	Day	21% 4 5% 23% 30% 18%	3316
	21st to end	Day	16% 2 4 28% 38% 11%	3378
November	1st to 10th	Day	23% 3 7% 21% 30% 16%	1763
	11th to 20th	Day	18% 3 6% 24% 33% 16%	1800
	21st to end	Day	26% 2 6% 19% 31% 16%	1800
December	1st to 10th	Day	26% 3 5% 34% 24% 8%	2940
	11th to 20th	Day	23% 2 8% 16% 34% 16%	3389
	21st to end	Day	31% 3 7% 23% 26% 10%	4488
January	1st to 10th	Night	30% 2 6% 32% 22% 7%	5888
	11th to 20th	Night	16% 3 8% 20% 38% 15%	5900
	21st to end	Night	32% 3 6% 17% 28% 14%	6278
February	1st to 10th	Night	28% 3 7% 19% 28% 15%	2400
	11th to 20th	Night	28% 3 8% 21% 24% 16%	2338
	21st to end	Night	27% 4 5% 16% 26% 23%	1980
March	1st to 10th	Night	26% 3 4 12% 22% 33%	5292
	11th to 20th	Night	20% 3 6% 18% 18% 35%	4980
	21st to end	Night	24% 5% 8% 20% 30% 12%	5467
April	1st to 10th	Night	25% 4 7% 18% 25% 20%	2105
	11th to 20th	Night	26% 5% 10% 18% 25% 16%	1977
	21st to end	Night	24% 5% 10% 24% 26% 10%	1869
May	1st to 10th	Night	31% 6% 12% 21% 16% 15%	4080
	11th to 20th	Night	24% 6% 9% 16% 24% 23%	4054
	21st to end	Night	29% 7% 11% 17% 17% 19%	4452
June	1st to 10th	Night	21% 7% 16% 30% 19% 7%	1800
	11th to 20th	Night	19% 5% 13% 26% 27% 9%	1800
	21st to end	Night	20% 5% 11% 26% 26% 13%	1800
July	1st to 10th	Night	32% 6% 11% 28% 19% 4	4035
	11th to 20th	Night	15% 5% 10% 32% 29% 9%	4026
	21st to end	Night	16% 4 13% 31% 30% 6%	4320
August	1st to 10th	Night	12% 4 8% 24% 33% 20%	2930
	11th to 20th	Night	16% 5% 13% 26% 29% 11%	3243
	21st to end	Night	16% 4 13% 30% 28% 9%	3597
September	1st to 10th	Night	26% 5% 10% 19% 26% 14%	2066
	11th to 20th	Night	31% 4 12% 19% 23% 11%	2090
	21st to end	Night	24% 4 7% 20% 28% 17%	2090
October	1st to 10th	Night	13% 3 6% 14% 34% 31%	3480
	11th to 20th	Night	22% 2 6% 19% 30% 21%	3555
	21st to end	Night	15% 2 4 23% 39% 16%	4168
November	1st to 10th	Night	20% 3 8% 22% 29% 19%	2535
	11th to 20th	Night	18% 4 6% 21% 34% 18%	2600
	21st to end	Night	24% 4 6% 18% 31% 17%	2600
December	1st to 10th	Night	23% 2 5% 28% 30% 11%	4250
	11th to 20th	Night	21% 3 6% 19% 34% 18%	4817
	21st to end	Night	28% 4 7% 25% 26% 11%	6490

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	9% 9% 41% 29% 11% 1	300
	11th to 20th	Day	14% 13% 29% 32% 12%	300
	21st to end	Day	10% 12% 36% 32% 9% 1	330
February	1st to 10th	Day	13% 11% 36% 30% 9% 1	300
	11th to 20th	Day	12% 10% 44% 26% 7%	300
	21st to end	Day	17% 15% 34% 26% 7% 1	249
March	1st to 10th	Day	12% 10% 38% 32% 8%	300
	11th to 20th	Day	17% 13% 38% 22% 8% 2	300
	21st to end	Day	10% 11% 43% 26% 10%	330
April	1st to 10th	Day	14% 13% 41% 21% 10% 1	390
	11th to 20th	Day	14% 13% 47% 24% 3	492
	21st to end	Day	11% 13% 40% 28% 7% 2	630
May	1st to 10th	Day	9% 8% 39% 34% 10% 1	703
	11th to 20th	Day	12% 8% 31% 31% 16% 3	725
	21st to end	Day	9% 8% 29% 35% 16% 4	789
June	1st to 10th	Day	5% 2 19% 43% 25% 5%	730
	11th to 20th	Day	4 3 20% 45% 24% 3	730
	21st to end	Day	3 2 13% 43% 32% 6%	730
July	1st to 10th	Day	6% 1 7% 36% 36% 13%	721
	11th to 20th	Day	3 1 6% 35% 45% 10%	718
	21st to end	Day	3 1 5% 32% 45% 15%	794
August	1st to 10th	Day	4 1 6% 34% 42% 12%	720
	11th to 20th	Day	4 1 8% 37% 37% 13%	517
	21st to end	Day	4 1 6% 30% 42% 17%	583
September	1st to 10th	Day	10% 1 4 30% 36% 18%	364
	11th to 20th	Day	6% 1 8% 34% 37% 14%	300
	21st to end	Day	11% 3 8% 30% 34% 14%	300
October	1st to 10th	Day	3 3 21% 31% 34% 7%	300
	11th to 20th	Day	8% 5% 27% 37% 22% 2	300
	21st to end	Day	17% 8% 25% 30% 18% 3	330
November	1st to 10th	Day	14% 4 34% 28% 17% 3	300
	11th to 20th	Day	11% 8% 28% 30% 19% 4	300
	21st to end	Day	16% 10% 34% 24% 13% 4	300
December	1st to 10th	Day	8% 7% 39% 33% 12% 1	300
	11th to 20th	Day	7% 9% 33% 36% 12% 2	300
	21st to end	Day	17% 12% 39% 22% 9% 2	330
January	1st to 10th	Night	8% 8% 37% 37% 9%	1000
	11th to 20th	Night	9% 9% 33% 40% 8%	1000
	21st to end	Night	9% 8% 38% 37% 7%	1005
February	1st to 10th	Night	11% 9% 40% 32% 8%	800
	11th to 20th	Night	12% 10% 42% 31% 5%	784
	21st to end	Night	11% 12% 45% 28% 3	660
March	1st to 10th	Night	10% 13% 43% 30% 5%	770
	11th to 20th	Night	13% 12% 42% 27% 6%	600
	21st to end	Night	6% 13% 47% 30% 3	660
April	1st to 10th	Night	9% 11% 50% 27% 4	600
	11th to 20th	Night	12% 12% 50% 23% 3	593
	21st to end	Night	9% 10% 47% 29% 5%	600
May	1st to 10th	Night	9% 9% 47% 31% 5%	600
	11th to 20th	Night	9% 7% 41% 31% 12% 1	591
	21st to end	Night	7% 6% 39% 37% 10% 1	650
June	1st to 10th	Night	5% 3 31% 46% 14% 1	600
	11th to 20th	Night	3 2 35% 52% 8%	600
	21st to end	Night	4 2 26% 46% 23% 1	600
July	1st to 10th	Night	4 2 12% 46% 33% 2	585
	11th to 20th	Night	3 1 9% 54% 31% 2	582
	21st to end	Night	3 1 5% 52% 39% 2	657
August	1st to 10th	Night	1 7% 55% 35% 1	597
	11th to 20th	Night	5% 1 10% 48% 35% 1	594
	21st to end	Night	3 1 8% 46% 39% 3	660
September	1st to 10th	Night	7% 2 11% 47% 31% 2	579
	11th to 20th	Night	11% 2 18% 42% 27% 1	570
	21st to end	Night	8% 2 20% 44% 25% 1	570
October	1st to 10th	Night	7% 4 26% 42% 20% 1	570
	11th to 20th	Night	8% 4 34% 41% 11%	627
	21st to end	Night	8% 9% 32% 35% 16%	860
November	1st to 10th	Night	9% 5% 33% 39% 13% 1	975
	11th to 20th	Night	5% 7% 37% 38% 11% 1	1000
	21st to end	Night	10% 7% 34% 36% 11% 1	1000
December	1st to 10th	Night	10% 9% 31% 41% 10%	1000
	11th to 20th	Night	11% 7% 38% 37% 7%	1000
	21st to end	Night	11% 7% 38% 36% 7%	1100

Page generated at 2025-09-01 00:51:07. Version ac07

Copyright © 2025 Attilla Danko.