Caprock Canyons Trailway
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caprock Canyons Trailway clear sky chart from 2005-11-06 to 2024-04-10.

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 3 3 2 3 4 4 7% 60%	83542
	Night	6% 4 2 3 3 2 3 4 5% 7% 61%	85317
Transparency	Day	25% 4 8% 23% 26% 14%	83270
	Night	23% 4 8% 22% 27% 16%	85112
Seeing	Day	8% 7% 24% 33% 22% 6%	14373
	Night	8% 7% 30% 40% 15% 1	24501

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	7% 6% 3 5% 4 2 3 4 4 4 58%	2847
	11th to 20th	Day	4 4 1 3 3 2 4 3 4 6% 67%	2850
	21st to end	Day	10% 6% 2 3 4 3 4 3 4 6% 55%	3432
February	1st to 10th	Day	7% 5% 2 4 3 2 3 2 3 6% 62%	1900
	11th to 20th	Day	7% 5% 2 5% 3 2 3 3 4 7% 60%	1849
	21st to end	Day	6% 7% 2 4 3 2 3 4 3 5% 60%	1570
March	1st to 10th	Day	8% 4 2 3 3 2 2 3 4 7% 62%	3130
	11th to 20th	Day	10% 4 2 3 3 2 3 3 4 6% 59%	3417
	21st to end	Day	6% 7% 3 4 4 3 4 4 4 7% 54%	3837
April	1st to 10th	Day	7% 3 2 3 3 1 3 2 4 6% 65%	2269
	11th to 20th	Day	10% 4 2 4 3 2 3 4 4 5% 57%	2131
	21st to end	Day	8% 3 1 3 3 2 3 4 5% 6% 61%	2210
May	1st to 10th	Day	10% 4 2 4 3 2 4 3 4 5% 59%	2340
	11th to 20th	Day	11% 4 2 4 4 2 3 4 5% 7% 56%	2302
	21st to end	Day	8% 3 2 4 4 3 4 5% 5% 8% 54%	2531
June	1st to 10th	Day	6% 3 2 3 3 2 4 5% 6% 9% 56%	2340
	11th to 20th	Day	6% 3 1 3 3 2 4 4 6% 8% 61%	2340
	21st to end	Day	4 3 1 3 3 2 4 4 6% 7% 63%	2340
July	1st to 10th	Day	7% 2 2 3 4 3 5% 7% 6% 9% 53%	2340
	11th to 20th	Day	4 1 1 3 4 2 4 3 5% 8% 63%	2340
	21st to end	Day	2 2 1 3 3 3 5% 5% 5% 10% 60%	2546
August	1st to 10th	Day	3 2 1 4 3 2 4 6% 7% 9% 59%	2227
	11th to 20th	Day	6% 3 2 3 5% 3 5% 5% 6% 9% 54%	2123
	21st to end	Day	6% 3 1 4 4 3 5% 5% 5% 9% 55%	2376
September	1st to 10th	Day	9% 3 2 4 3 3 3 4 5% 8% 58%	2093
	11th to 20th	Day	9% 4 1 4 4 3 4 5% 4 8% 52%	1980
	21st to end	Day	7% 3 1 3 3 2 2 4 4 6% 63%	1980
October	1st to 10th	Day	8% 3 2 4 4 3 3 3 3 5% 62%	1980
	11th to 20th	Day	8% 3 1 3 2 2 3 3 3 4 67%	1969
	21st to end	Day	8% 5% 1 3 2 2 2 2 3 4 67%	1854
November	1st to 10th	Day	6% 3 2 2 2 2 2 3 4 6% 68%	1673
	11th to 20th	Day	4 3 1 2 2 2 3 3 3 6% 71%	1710
	21st to end	Day	9% 5% 2 3 2 2 3 3 4 6% 62%	1710
December	1st to 10th	Day	6% 4 2 4 4 3 3 4 4 5% 61%	1710
	11th to 20th	Day	8% 3 2 4 3 3 3 5% 4 6% 60%	2161
	21st to end	Day	7% 6% 2 4 4 2 3 3 3 5% 60%	3135
January	1st to 10th	Night	7% 6% 2 4 3 2 3 3 4 7% 60%	4108
	11th to 20th	Night	4 2 2 3 3 2 3 4 5% 6% 66%	4120
	21st to end	Night	10% 6% 3 4 4 2 3 3 4 5% 56%	4262
February	1st to 10th	Night	7% 6% 2 4 4 2 3 3 3 6% 60%	2280
	11th to 20th	Night	7% 5% 2 4 4 2 3 3 4 6% 59%	2218
	21st to end	Night	7% 4 1 3 4 2 3 3 5% 7% 61%	1884
March	1st to 10th	Night	6% 5% 2 4 4 2 2 3 3 5% 64%	3734
	11th to 20th	Night	7% 4 2 4 3 3 3 3 4 5% 62%	3544
	21st to end	Night	5% 5% 3 6% 4 3 4 4 4 6% 55%	3791
April	1st to 10th	Night	5% 3 2 2 3 2 3 4 5% 7% 65%	1900
	11th to 20th	Night	8% 4 1 3 4 3 3 4 5% 7% 57%	1777
	21st to end	Night	8% 2 1 3 2 1 3 3 5% 7% 64%	1746
May	1st to 10th	Night	9% 4 1 3 3 2 3 4 5% 7% 59%	1620
	11th to 20th	Night	9% 3 2 3 4 2 4 5% 6% 7% 56%	1593
	21st to end	Night	8% 3 1 3 4 2 4 4 6% 8% 58%	1745
June	1st to 10th	Night	5% 2 1 3 4 2 4 5% 8% 11% 55%	1620
	11th to 20th	Night	3 2 1 2 3 3 4 5% 7% 11% 58%	1620
	21st to end	Night	4 2 1 2 3 2 5% 4 5% 10% 62%	1620
July	1st to 10th	Night	5% 3 1 3 4 3 5% 5% 7% 10% 54%	1620
	11th to 20th	Night	4 2 1 3 4 2 4 4 6% 9% 61%	1620
	21st to end	Night	3 2 1 2 3 2 4 4 6% 11% 62%	1772
August	1st to 10th	Night	2 1 1 3 4 2 4 5% 7% 10% 59%	1708
	11th to 20th	Night	7% 4 2 4 5% 3 6% 6% 7% 9% 48%	1778
	21st to end	Night	4 2 2 3 3 2 4 5% 5% 10% 60%	1980
September	1st to 10th	Night	7% 4 1 4 5% 2 4 5% 5% 6% 57%	1866
	11th to 20th	Night	11% 4 2 4 4 2 4 5% 6% 7% 51%	1980
	21st to end	Night	6% 2 1 2 2 2 3 4 5% 5% 66%	1980
October	1st to 10th	Night	9% 3 1 3 2 2 3 3 4 6% 64%	1980
	11th to 20th	Night	9% 3 1 2 2 1 2 3 3 4 71%	1980
	21st to end	Night	7% 3 1 2 2 2 2 2 3 5% 71%	2488
November	1st to 10th	Night	6% 2 1 2 2 1 2 3 4 6% 71%	2405
	11th to 20th	Night	4 3 1 2 2 2 2 2 3 6% 72%	2470
	21st to end	Night	7% 3 2 3 3 2 3 4 4 6% 63%	2470
December	1st to 10th	Night	8% 4 1 3 3 3 3 3 3 5% 64%	2470
	11th to 20th	Night	7% 4 2 3 4 2 4 4 5% 7% 59%	3036
	21st to end	Night	6% 5% 1 4 4 2 3 4 5% 7% 60%	4532

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% 4 5% 21% 26% 15%	2848
	11th to 20th	Day	21% 3 7% 26% 30% 14%	2850
	21st to end	Day	31% 4 7% 21% 30% 8%	3432
February	1st to 10th	Day	25% 3 7% 24% 26% 15%	1900
	11th to 20th	Day	27% 3 6% 24% 24% 16%	1859
	21st to end	Day	28% 3 4 15% 31% 19%	1570
March	1st to 10th	Day	23% 4 5% 13% 26% 29%	3130
	11th to 20th	Day	28% 3 7% 25% 27% 11%	3417
	21st to end	Day	29% 6% 6% 22% 25% 11%	3837
April	1st to 10th	Day	22% 4 6% 18% 26% 23%	2269
	11th to 20th	Day	29% 4 6% 18% 23% 19%	2134
	21st to end	Day	23% 4 9% 23% 28% 13%	2210
May	1st to 10th	Day	29% 4 7% 17% 23% 20%	2340
	11th to 20th	Day	29% 5% 10% 25% 22% 10%	2306
	21st to end	Day	29% 6% 12% 22% 18% 12%	2531
June	1st to 10th	Day	24% 6% 15% 28% 17% 9%	2340
	11th to 20th	Day	21% 6% 11% 23% 24% 15%	2340
	21st to end	Day	20% 5% 12% 27% 24% 13%	2340
July	1st to 10th	Day	25% 8% 13% 30% 20% 5%	2276
	11th to 20th	Day	18% 4 10% 28% 31% 8%	2271
	21st to end	Day	18% 7% 14% 33% 25% 3	2405
August	1st to 10th	Day	19% 6% 14% 29% 24% 8%	2213
	11th to 20th	Day	27% 6% 15% 27% 19% 6%	2123
	21st to end	Day	25% 7% 11% 24% 22% 10%	2376
September	1st to 10th	Day	26% 6% 9% 24% 22% 13%	2093
	11th to 20th	Day	31% 6% 10% 20% 27% 6%	1980
	21st to end	Day	22% 5% 7% 22% 32% 13%	1980
October	1st to 10th	Day	27% 4 8% 23% 24% 13%	1980
	11th to 20th	Day	22% 3 5% 15% 30% 25%	1969
	21st to end	Day	23% 3 5% 22% 31% 16%	1854
November	1st to 10th	Day	19% 3 7% 18% 33% 20%	1673
	11th to 20th	Day	16% 4 5% 25% 34% 16%	1710
	21st to end	Day	25% 3 4 16% 32% 20%	1710
December	1st to 10th	Day	27% 3 6% 24% 28% 12%	1710
	11th to 20th	Day	26% 4 8% 19% 28% 14%	2159
	21st to end	Day	28% 4 6% 19% 32% 13%	3135
January	1st to 10th	Night	26% 3 7% 27% 27% 9%	4108
	11th to 20th	Night	19% 3 12% 20% 33% 13%	4120
	21st to end	Night	30% 5% 6% 19% 29% 11%	4262
February	1st to 10th	Night	28% 3 7% 17% 29% 16%	2280
	11th to 20th	Night	28% 3 6% 21% 24% 18%	2218
	21st to end	Night	24% 3 5% 17% 27% 24%	1884
March	1st to 10th	Night	24% 3 4 13% 24% 31%	3734
	11th to 20th	Night	25% 3 8% 25% 21% 18%	3544
	21st to end	Night	28% 5% 7% 25% 20% 15%	3791
April	1st to 10th	Night	20% 4 8% 18% 25% 25%	1900
	11th to 20th	Night	26% 5% 8% 17% 26% 17%	1777
	21st to end	Night	20% 4 11% 23% 27% 14%	1746
May	1st to 10th	Night	25% 5% 9% 17% 22% 22%	1620
	11th to 20th	Night	26% 7% 11% 20% 21% 14%	1594
	21st to end	Night	25% 6% 14% 23% 19% 14%	1746
June	1st to 10th	Night	21% 6% 18% 29% 17% 8%	1620
	11th to 20th	Night	19% 6% 12% 24% 25% 14%	1620
	21st to end	Night	20% 4 12% 26% 22% 16%	1620
July	1st to 10th	Night	23% 7% 16% 29% 18% 7%	1575
	11th to 20th	Night	17% 6% 11% 22% 31% 15%	1566
	21st to end	Night	16% 5% 12% 31% 30% 6%	1673
August	1st to 10th	Night	17% 6% 10% 30% 27% 10%	1698
	11th to 20th	Night	30% 6% 13% 23% 22% 6%	1778
	21st to end	Night	21% 6% 13% 27% 23% 10%	1980
September	1st to 10th	Night	26% 6% 10% 22% 23% 13%	1866
	11th to 20th	Night	32% 6% 12% 15% 28% 9%	1980
	21st to end	Night	19% 5% 8% 21% 29% 18%	1980
October	1st to 10th	Night	23% 3 10% 21% 26% 17%	1980
	11th to 20th	Night	20% 3 6% 15% 30% 26%	1980
	21st to end	Night	19% 2 5% 21% 33% 20%	2488
November	1st to 10th	Night	16% 3 7% 22% 30% 21%	2405
	11th to 20th	Night	16% 2 5% 22% 35% 19%	2470
	21st to end	Night	23% 4 4 18% 30% 21%	2470
December	1st to 10th	Night	25% 2 7% 23% 28% 16%	2470
	11th to 20th	Night	25% 4 5% 20% 31% 15%	3037
	21st to end	Night	23% 5% 6% 22% 30% 14%	4532

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% 11% 34% 32% 12% 2	270
	11th to 20th	Day	14% 12% 28% 33% 12% 1	270
	21st to end	Day	7% 10% 37% 32% 12% 1	297
February	1st to 10th	Day	11% 13% 33% 33% 10%	270
	11th to 20th	Day	9% 10% 44% 24% 12% 1	270
	21st to end	Day	16% 16% 35% 28% 4	225
March	1st to 10th	Day	9% 7% 44% 30% 10%	270
	11th to 20th	Day	14% 13% 36% 26% 8% 3	270
	21st to end	Day	13% 14% 34% 30% 9%	308
April	1st to 10th	Day	9% 17% 43% 22% 8%	457
	11th to 20th	Day	12% 16% 44% 22% 5%	412
	21st to end	Day	12% 17% 33% 28% 9% 2	470
May	1st to 10th	Day	10% 8% 38% 33% 11%	603
	11th to 20th	Day	12% 7% 27% 35% 17% 3	625
	21st to end	Day	9% 7% 31% 32% 18% 3	679
June	1st to 10th	Day	8% 3 20% 39% 26% 5%	630
	11th to 20th	Day	6% 3 24% 41% 21% 4	630
	21st to end	Day	5% 2 15% 38% 33% 7%	630
July	1st to 10th	Day	5% 1 6% 38% 35% 15%	621
	11th to 20th	Day	3 1 9% 32% 42% 14%	618
	21st to end	Day	2 4 32% 45% 16%	684
August	1st to 10th	Day	3 2 7% 38% 42% 9%	525
	11th to 20th	Day	4 2 9% 39% 31% 16%	437
	21st to end	Day	6% 2 8% 33% 37% 14%	495
September	1st to 10th	Day	7% 2 7% 36% 33% 14%	383
	11th to 20th	Day	6% 12% 37% 36% 10%	270
	21st to end	Day	11% 3 12% 31% 32% 11%	270
October	1st to 10th	Day	8% 3 25% 34% 26% 4	270
	11th to 20th	Day	7% 6% 25% 33% 26% 3	270
	21st to end	Day	16% 6% 27% 27% 21% 3	297
November	1st to 10th	Day	13% 6% 30% 29% 19% 4	270
	11th to 20th	Day	7% 9% 28% 34% 17% 5%	270
	21st to end	Day	17% 11% 30% 22% 16% 4	270
December	1st to 10th	Day	7% 7% 40% 29% 16% 1	270
	11th to 20th	Day	6% 10% 31% 39% 12% 1	270
	21st to end	Day	14% 14% 37% 27% 8%	297
January	1st to 10th	Night	7% 8% 34% 41% 11%	950
	11th to 20th	Night	9% 9% 33% 40% 9%	950
	21st to end	Night	7% 8% 32% 44% 8% 1	879
February	1st to 10th	Night	11% 9% 35% 37% 7% 1	760
	11th to 20th	Night	9% 10% 39% 36% 5%	744
	21st to end	Night	11% 11% 38% 35% 4	628
March	1st to 10th	Night	10% 12% 41% 33% 5%	760
	11th to 20th	Night	13% 12% 37% 31% 8%	608
	21st to end	Night	7% 15% 43% 31% 4	627
April	1st to 10th	Night	6% 12% 44% 34% 3	570
	11th to 20th	Night	11% 11% 50% 26% 2	533
	21st to end	Night	10% 9% 43% 33% 4	540
May	1st to 10th	Night	10% 8% 43% 34% 5%	540
	11th to 20th	Night	10% 5% 32% 40% 12% 1	531
	21st to end	Night	9% 5% 36% 38% 11% 1	584
June	1st to 10th	Night	5% 3 29% 45% 18%	540
	11th to 20th	Night	4 3 38% 45% 9%	540
	21st to end	Night	5% 2 22% 47% 23% 1	540
July	1st to 10th	Night	5% 2 11% 46% 34% 2	525
	11th to 20th	Night	4 11% 47% 36% 1	522
	21st to end	Night	3 1 5% 46% 44% 2	591
August	1st to 10th	Night	3 1 7% 48% 40% 1	537
	11th to 20th	Night	7% 2 9% 45% 37% 1	534
	21st to end	Night	5% 1 8% 41% 43% 2	594
September	1st to 10th	Night	6% 2 10% 46% 34% 2	540
	11th to 20th	Night	13% 2 14% 43% 28% 1	540
	21st to end	Night	6% 2 20% 44% 27% 2	540
October	1st to 10th	Night	11% 4 25% 43% 17% 1	540
	11th to 20th	Night	10% 4 31% 43% 12%	540
	21st to end	Night	8% 7% 31% 36% 17% 1	904
November	1st to 10th	Night	7% 6% 28% 44% 14% 1	925
	11th to 20th	Night	6% 8% 32% 41% 13% 1	950
	21st to end	Night	9% 8% 33% 38% 12% 1	950
December	1st to 10th	Night	11% 6% 31% 43% 9%	950
	11th to 20th	Night	11% 8% 35% 39% 7%	950
	21st to end	Night	11% 8% 35% 39% 7%	1045

Page generated at 2024-04-07 08:28:10. Version ac07

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