Dark Sky New Mexico
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dark Sky New Mexico clear sky chart from 2005-11-05 to 2017-12-20.

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	3 2 1 2 3 2 4 4 5% 6% 63%	48836
	Night	2 2 1 2 3 2 3 4 4 6% 64%	48198
Transparency	Day	20% 4 7% 14% 26% 26%	48531
	Night	19% 4 7% 15% 28% 25%	48004
Seeing	Day	5% 8% 20% 30% 24% 9%	5535
	Night	3 3 18% 40% 30% 3	15725

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 15th	Day	2 2 1 2 3 2 3 5% 4 8% 63%	1611
	16th to end	Day	4 4 2 3 2 1 3 3 4 7% 61%	1728
February	1st to 15th	Day	2 2 2 2 1 3 2 4 5% 70%	1575
	16th to end	Day	3 2 1 2 2 1 3 3 4 5% 69%	1718
March	1st to 15th	Day	1 2 1 2 2 1 3 4 3 7% 68%	1980
	16th to end	Day	2 2 1 2 2 1 2 2 4 4 73%	2112
April	1st to 15th	Day	2 1 1 2 1 2 2 4 6% 72%	2082
	16th to end	Day	1 1 1 1 1 1 2 2 3 82%	2160
May	1st to 15th	Day	1 1 2 2 1 3 3 3 5% 75%	2193
	16th to end	Day	1 1 1 2 1 2 2 3 5% 76%	2429
June	1st to 15th	Day	2 1 1 2 1 2 2 3 6% 73%	2340
	16th to end	Day	2 2 1 2 4 2 4 4 5% 7% 62%	2340
July	1st to 15th	Day	4 3 1 4 5% 5% 7% 7% 8% 11% 41%	2340
	16th to end	Day	7% 4 3 5% 6% 4 8% 7% 8% 10% 32%	2467
August	1st to 15th	Day	5% 5% 1 5% 5% 4 6% 7% 8% 11% 37%	2301
	16th to end	Day	5% 4 2 4 5% 3 6% 7% 7% 10% 42%	2292
September	1st to 15th	Day	6% 4 2 4 7% 4 7% 5% 6% 7% 45%	2109
	16th to end	Day	4 2 2 3 1 3 3 5% 6% 65%	1974
October	1st to 15th	Day	1 2 2 3 1 2 3 4 6% 71%	1800
	16th to end	Day	1 1 1 1 2 1 2 2 3 4 77%	1920
November	1st to 15th	Day	1 2 2 1 2 2 4 6% 74%	1909
	16th to end	Day	3 2 1 2 3 1 2 2 3 4 71%	1937
December	1st to 15th	Day	3 2 1 3 3 1 3 4 4 6% 64%	1755
	16th to end	Day	3 4 1 3 3 1 3 3 5% 5% 63%	1764
January	1st to 15th	Night	4 3 1 3 2 1 2 3 4 6% 65%	2327
	16th to end	Night	4 2 1 3 2 2 3 3 4 5% 63%	2496
February	1st to 15th	Night	1 2 1 2 2 2 3 3 4 5% 70%	2277
	16th to end	Night	1 2 1 2 2 1 3 2 3 5% 70%	1753
March	1st to 15th	Night	3 2 1 2 2 1 2 3 4 6% 70%	1980
	16th to end	Night	1 1 1 2 1 3 2 3 4 76%	2112
April	1st to 15th	Night	2 1 1 3 1 3 3 4 5% 69%	1864
	16th to end	Night	1 1 1 1 1 1 2 2 4 81%	1800
May	1st to 15th	Night	1 1 2 2 1 2 3 3 5% 75%	1754
	16th to end	Night	2 1 2 2 1 2 3 3 4 76%	1684
June	1st to 15th	Night	2 1 1 2 1 1 1 3 4 5% 75%	1620
	16th to end	Night	1 1 1 2 3 2 5% 5% 7% 8% 59%	1620
July	1st to 15th	Night	2 3 1 3 5% 4 9% 9% 9% 11% 37%	1620
	16th to end	Night	3 3 2 4 6% 4 10% 11% 11% 13% 27%	1701
August	1st to 15th	Night	3 3 1 4 6% 3 7% 7% 9% 11% 40%	1659
	16th to end	Night	4 3 1 4 6% 4 5% 7% 8% 10% 42%	1910
September	1st to 15th	Night	5% 4 2 5% 5% 3 6% 6% 7% 10% 42%	1848
	16th to end	Night	3 3 1 2 3 1 2 3 3 5% 69%	1986
October	1st to 15th	Night	1 1 1 2 3 1 3 3 4 5% 72%	2160
	16th to end	Night	1 1 1 1 1 2 2 3 4 78%	2304
November	1st to 15th	Night	1 1 1 1 1 2 3 2 7% 75%	2280
	16th to end	Night	3 2 1 2 2 2 2 2 2 5% 71%	2350
December	1st to 15th	Night	3 3 1 2 2 1 3 3 4 6% 65%	2535
	16th to end	Night	3 3 1 3 3 2 4 3 4 5% 64%	2558

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 15th	Day	18% 4 7% 17% 33% 17%	1612
	16th to end	Day	23% 3 4 15% 33% 18%	1728
February	1st to 15th	Day	16% 2 5% 14% 30% 30%	1575
	16th to end	Day	17% 2 5% 13% 34% 27%	1718
March	1st to 15th	Day	16% 2 4 11% 34% 30%	1980
	16th to end	Day	15% 1 4 11% 33% 35%	2112
April	1st to 15th	Day	12% 2 3 10% 36% 34%	2082
	16th to end	Day	10% 2 7% 25% 53%	2160
May	1st to 15th	Day	12% 2 4 8% 26% 45%	2193
	16th to end	Day	12% 2 4 9% 25% 46%	2432
June	1st to 15th	Day	12% 2 3 7% 21% 52%	2340
	16th to end	Day	20% 3 7% 10% 21% 36%	2340
July	1st to 15th	Day	30% 9% 16% 17% 13% 11%	2201
	16th to end	Day	39% 13% 18% 19% 8% 1	2312
August	1st to 15th	Day	36% 10% 16% 19% 13% 4	2286
	16th to end	Day	33% 9% 14% 15% 16% 10%	2292
September	1st to 15th	Day	34% 7% 11% 16% 17% 11%	2109
	16th to end	Day	19% 3 5% 16% 33% 21%	1974
October	1st to 15th	Day	15% 3 6% 16% 27% 31%	1800
	16th to end	Day	11% 2 4 17% 32% 31%	1920
November	1st to 15th	Day	12% 1 5% 19% 34% 25%	1909
	16th to end	Day	17% 2 3 15% 34% 26%	1937
December	1st to 15th	Day	20% 2 6% 21% 33% 15%	1755
	16th to end	Day	22% 3 8% 22% 31% 11%	1764
January	1st to 15th	Night	20% 4 6% 17% 32% 18%	2327
	16th to end	Night	22% 3 4 19% 33% 17%	2496
February	1st to 15th	Night	15% 2 4 16% 31% 28%	2288
	16th to end	Night	16% 2 5% 15% 34% 26%	1753
March	1st to 15th	Night	15% 2 4 13% 33% 31%	1980
	16th to end	Night	13% 1 4 10% 37% 32%	2112
April	1st to 15th	Night	15% 1 4 11% 35% 31%	1864
	16th to end	Night	9% 2 3 7% 30% 46%	1800
May	1st to 15th	Night	11% 1 4 9% 27% 45%	1755
	16th to end	Night	13% 2 5% 11% 26% 41%	1685
June	1st to 15th	Night	12% 1 4 7% 23% 50%	1620
	16th to end	Night	20% 5% 7% 13% 19% 34%	1620
July	1st to 15th	Night	29% 14% 15% 18% 12% 9%	1530
	16th to end	Night	36% 16% 22% 17% 5% 1	1593
August	1st to 15th	Night	32% 11% 18% 19% 14% 4	1650
	16th to end	Night	31% 11% 15% 17% 14% 8%	1910
September	1st to 15th	Night	32% 8% 14% 15% 16% 11%	1848
	16th to end	Night	18% 3 5% 16% 36% 18%	1986
October	1st to 15th	Night	14% 3 8% 15% 26% 32%	2160
	16th to end	Night	10% 2 3 16% 30% 36%	2304
November	1st to 15th	Night	11% 2 4 20% 34% 26%	2280
	16th to end	Night	18% 2 3 12% 33% 29%	2350
December	1st to 15th	Night	19% 2 6% 22% 32% 16%	2535
	16th to end	Night	21% 4 8% 22% 32% 12%	2558

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 15th	Day	7% 8% 25% 43% 13% 1	90
	16th to end	Day	6% 9% 19% 35% 21% 7%	96
February	1st to 15th	Day	8% 4 12% 35% 33% 5%	90
	16th to end	Day	10% 21% 31% 20% 15% 1	219
March	1st to 15th	Day	6% 17% 30% 25% 15% 5%	270
	16th to end	Day	8% 18% 28% 28% 10% 6%	288
April	1st to 15th	Day	7% 19% 28% 29% 11% 3	269
	16th to end	Day	3 24% 32% 27% 9% 2	270
May	1st to 15th	Day	4 19% 37% 23% 12% 3	288
	16th to end	Day	4 9% 34% 34% 16% 1	330
June	1st to 15th	Day	5% 2 25% 38% 18% 9%	315
	16th to end	Day	5% 11% 38% 30% 12%	315
July	1st to 15th	Day	4 7% 36% 39% 10%	305
	16th to end	Day	6% 8% 25% 35% 24%	327
August	1st to 15th	Day	5% 1 6% 28% 35% 22%	315
	16th to end	Day	5% 1 4 27% 43% 18%	332
September	1st to 15th	Day	9% 9% 35% 34% 10%	315
	16th to end	Day	6% 6% 19% 31% 28% 7%	309
October	1st to 15th	Day	2 16% 31% 28% 19%	135
	16th to end	Day	2 15% 25% 36% 20%	144
November	1st to 15th	Day	2 8% 21% 31% 24% 11%	135
	16th to end	Day	6% 11% 20% 32% 21% 8%	135
December	1st to 15th	Day	6% 10% 20% 26% 27% 8%	135
	16th to end	Day	8% 15% 29% 34% 12%	108
January	1st to 15th	Night	5% 3 20% 44% 23% 2	720
	16th to end	Night	5% 5% 21% 42% 23% 1	768
February	1st to 15th	Night	3 6% 20% 41% 24% 3	704
	16th to end	Night	2 6% 31% 45% 14%	632
March	1st to 15th	Night	3 6% 29% 39% 17% 2	720
	16th to end	Night	2 5% 24% 43% 22% 2	768
April	1st to 15th	Night	3 8% 30% 42% 13% 1	605
	16th to end	Night	2 8% 32% 40% 15% 1	540
May	1st to 15th	Night	2 5% 29% 44% 17% 1	540
	16th to end	Night	2 3 24% 47% 20%	563
June	1st to 15th	Night	2 1 13% 55% 25%	540
	16th to end	Night	1 1 8% 49% 37% 1	540
July	1st to 15th	Night	4 6% 37% 46% 4	510
	16th to end	Night	5% 3 28% 55% 7%	564
August	1st to 15th	Night	4 3 22% 56% 12%	539
	16th to end	Night	5% 4 24% 56% 9%	573
September	1st to 15th	Night	6% 1 6% 30% 51% 4	588
	16th to end	Night	5% 13% 37% 38% 4	716
October	1st to 15th	Night	1 16% 44% 33% 3	720
	16th to end	Night	2 1 12% 40% 36% 6%	768
November	1st to 15th	Night	1 2 18% 40% 31% 5%	760
	16th to end	Night	4 2 21% 37% 30% 3	780
December	1st to 15th	Night	5% 2 19% 42% 25% 3	780
	16th to end	Night	4 5% 22% 41% 21% 3	787

Page generated at 2017-12-21 05:04:53. Version ac04

Copyright 2017 A. Danko