New Mexico Astronomy Village
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the New Mexico Astronomy Village clear sky chart from 2005-11-06 to 2026-09-14.

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 3 3 3 4 3 5% 7% 66%	156840
	Night	3 3 1 4 3 3 4 3 5% 7% 63%	151858
Transparency	Day	17% 3 6% 15% 28% 30%	151826
	Night	20% 3 6% 15% 28% 28%	147879
Seeing	Day	6% 8% 21% 31% 24% 10%	16929
	Night	5% 4 24% 41% 23% 3	26867

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	3 6% 2 5% 3 3 4 3 4 5% 62%	5318
	11th to 20th	Day	1 1 1 1 1 2 2 3 5% 82%	5340
	21st to end	Day	6% 4 1 4 3 3 3 3 5% 6% 62%	5844
February	1st to 10th	Day	3 3 1 4 2 2 3 3 3 6% 70%	1890
	11th to 20th	Day	5% 3 1 3 3 3 4 3 3 6% 66%	2007
	21st to end	Day	4 3 1 2 3 2 3 2 4 5% 70%	1868
March	1st to 10th	Day	2 3 1 4 2 2 3 2 4 6% 70%	5064
	11th to 20th	Day	5% 3 1 3 2 3 3 3 4 6% 67%	5110
	21st to end	Day	1 3 1 4 3 4 4 3 5% 7% 64%	5607
April	1st to 10th	Day	2 2 1 3 2 2 2 3 4 6% 73%	2466
	11th to 20th	Day	2 2 1 2 2 2 2 1 3 5% 78%	2491
	21st to end	Day	2 2 1 1 2 1 1 2 3 5% 80%	2520
May	1st to 10th	Day	1 2 1 2 2 2 3 2 4 5% 77%	7057
	11th to 20th	Day	1 1 2 2 2 2 2 4 4 81%	7312
	21st to end	Day	1 1 1 2 2 2 2 2 3 4 82%	8370
June	1st to 10th	Day	3 2 1 3 3 2 3 3 4 7% 69%	2730
	11th to 20th	Day	2 2 1 2 2 2 3 2 5% 5% 75%	2730
	21st to end	Day	4 3 1 4 4 4 5% 4 7% 8% 57%	2730
July	1st to 10th	Day	2 2 1 4 4 4 5% 4 7% 9% 57%	7649
	11th to 20th	Day	2 2 1 4 4 6% 6% 5% 8% 12% 50%	7650
	21st to end	Day	3 3 1 5% 4 5% 6% 6% 9% 12% 44%	8304
August	1st to 10th	Day	2 2 1 3 4 5% 5% 5% 7% 10% 56%	7481
	11th to 20th	Day	2 2 1 4 3 4 5% 4 7% 11% 56%	7003
	21st to end	Day	2 2 1 4 4 4 6% 5% 7% 10% 56%	7751
September	1st to 10th	Day	7% 4 2 5% 5% 4 5% 4 7% 8% 50%	2520
	11th to 20th	Day	6% 3 1 4 2 3 4 3 5% 7% 61%	2372
	21st to end	Day	3 2 1 3 2 2 2 3 4 6% 71%	2132
October	1st to 10th	Day	2 1 1 2 2 1 2 2 4 5% 78%	3270
	11th to 20th	Day	3 2 1 3 2 2 2 2 3 4 75%	3250
	21st to end	Day	1 1 1 1 1 1 1 2 2 3 86%	3548
November	1st to 10th	Day	2 1 1 2 3 2 2 2 4 6% 75%	2059
	11th to 20th	Day	2 3 1 3 2 2 3 3 3 5% 72%	2100
	21st to end	Day	5% 4 1 3 3 3 3 3 4 6% 63%	2100
December	1st to 10th	Day	6% 3 1 3 2 2 3 2 4 5% 68%	3089
	11th to 20th	Day	3 4 2 4 3 2 3 2 3 7% 68%	3499
	21st to end	Day	3 2 1 2 2 3 3 3 4 7% 72%	4609
January	1st to 10th	Night	4 6% 2 5% 3 3 4 3 5% 6% 58%	7605
	11th to 20th	Night	1 1 1 1 2 2 2 3 4 82%	7650
	21st to end	Night	7% 4 2 4 3 3 4 4 5% 6% 59%	8370
February	1st to 10th	Night	3 2 1 3 3 3 4 3 4 7% 68%	2730
	11th to 20th	Night	5% 4 1 3 3 2 3 3 3 6% 67%	2497
	21st to end	Night	3 3 1 3 2 3 3 3 4 6% 69%	1934
March	1st to 10th	Night	2 2 1 2 2 2 3 3 5% 6% 72%	5050
	11th to 20th	Night	5% 3 1 2 2 2 3 3 5% 5% 69%	5110
	21st to end	Night	1 2 1 3 2 3 4 3 5% 7% 68%	5610
April	1st to 10th	Night	1 2 1 2 2 2 3 3 4 6% 73%	2153
	11th to 20th	Night	2 2 1 3 3 2 2 2 4 5% 74%	2077
	21st to end	Night	2 1 2 2 2 3 3 4 4 77%	2100
May	1st to 10th	Night	3 3 1 3 2 2 3 2 4 6% 71%	5890
	11th to 20th	Night	1 1 1 2 2 2 3 2 4 6% 75%	5563
	21st to end	Night	1 1 1 3 2 2 2 2 3 4 78%	5837
June	1st to 10th	Night	3 2 1 4 2 3 3 4 5% 6% 66%	1890
	11th to 20th	Night	2 2 1 2 3 3 3 2 5% 5% 71%	1890
	21st to end	Night	4 4 1 5% 5% 4 6% 4 7% 8% 51%	1890
July	1st to 10th	Night	3 3 2 5% 5% 5% 6% 6% 9% 11% 45%	5340
	11th to 20th	Night	3 3 2 6% 6% 7% 8% 7% 11% 15% 33%	5340
	21st to end	Night	3 4 3 8% 6% 6% 7% 6% 9% 13% 34%	5805
August	1st to 10th	Night	2 3 2 7% 6% 7% 8% 6% 9% 13% 38%	5328
	11th to 20th	Night	3 3 2 6% 5% 6% 8% 7% 9% 16% 35%	5853
	21st to end	Night	3 4 2 7% 6% 7% 7% 5% 9% 12% 38%	6465
September	1st to 10th	Night	6% 4 2 7% 4 5% 6% 4 7% 7% 48%	2100
	11th to 20th	Night	5% 3 1 4 4 4 4 4 6% 8% 58%	2089
	21st to end	Night	4 2 1 4 2 3 3 2 4 5% 70%	2266
October	1st to 10th	Night	3 1 1 3 2 2 2 2 4 6% 74%	3920
	11th to 20th	Night	3 2 1 3 2 2 2 2 3 4 74%	3898
	21st to end	Night	2 1 2 1 1 2 1 3 4 83%	4252
November	1st to 10th	Night	2 1 1 2 2 2 3 3 4 5% 76%	2460
	11th to 20th	Night	3 2 1 3 2 2 3 3 4 6% 73%	2520
	21st to end	Night	6% 3 1 4 3 2 3 2 5% 5% 66%	2520
December	1st to 10th	Night	4 2 3 2 2 2 2 4 5% 74%	4304
	11th to 20th	Night	2 2 1 4 3 3 4 3 5% 6% 67%	4941
	21st to end	Night	4 3 1 3 2 2 2 2 4 5% 71%	6611

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	23% 3 4 15% 39% 17%	5321
	11th to 20th	Day	7% 2 3 12% 43% 33%	5340
	21st to end	Day	23% 3 3 14% 31% 27%	5844
February	1st to 10th	Day	17% 3 4 14% 27% 35%	1890
	11th to 20th	Day	21% 2 4 16% 31% 27%	2017
	21st to end	Day	17% 3 2 9% 32% 38%	1868
March	1st to 10th	Day	16% 2 3 6% 33% 41%	5064
	11th to 20th	Day	18% 3 3 15% 29% 32%	5110
	21st to end	Day	19% 3 4 10% 34% 31%	5607
April	1st to 10th	Day	13% 2 2 10% 35% 38%	2466
	11th to 20th	Day	12% 2 1 7% 27% 52%	2494
	21st to end	Day	10% 1 2 9% 30% 48%	2520
May	1st to 10th	Day	11% 2 3 12% 25% 47%	7057
	11th to 20th	Day	8% 2 3 8% 26% 53%	7315
	21st to end	Day	9% 1 2 7% 15% 66%	8371
June	1st to 10th	Day	15% 3 2 11% 26% 43%	2730
	11th to 20th	Day	11% 2 2 6% 19% 59%	2730
	21st to end	Day	22% 5% 6% 15% 20% 32%	2730
July	1st to 10th	Day	20% 4 10% 15% 27% 24%	7586
	11th to 20th	Day	23% 7% 17% 26% 21% 5%	7581
	21st to end	Day	27% 8% 15% 25% 18% 7%	8120
August	1st to 10th	Day	24% 6% 11% 33% 22% 4	5921
	11th to 20th	Day	19% 6% 13% 25% 29% 9%	5519
	21st to end	Day	22% 6% 11% 23% 27% 11%	6078
September	1st to 10th	Day	30% 4 10% 17% 23% 15%	2520
	11th to 20th	Day	21% 4 7% 18% 28% 22%	2372
	21st to end	Day	15% 3 5% 17% 33% 27%	2132
October	1st to 10th	Day	11% 2 5% 10% 24% 49%	3270
	11th to 20th	Day	15% 2 4 11% 30% 38%	3250
	21st to end	Day	7% 1 1 10% 32% 49%	3548
November	1st to 10th	Day	13% 2 4 16% 35% 30%	2059
	11th to 20th	Day	17% 2 3 16% 30% 31%	2100
	21st to end	Day	21% 3 4 17% 31% 23%	2100
December	1st to 10th	Day	20% 3 3 18% 36% 21%	3089
	11th to 20th	Day	20% 2 3 14% 38% 23%	3498
	21st to end	Day	14% 2 5% 17% 40% 22%	4609
January	1st to 10th	Night	27% 2 4 17% 37% 14%	7605
	11th to 20th	Night	9% 1 2 12% 44% 32%	7650
	21st to end	Night	26% 3 4 13% 27% 27%	8370
February	1st to 10th	Night	16% 3 4 17% 27% 33%	2730
	11th to 20th	Night	20% 2 3 17% 32% 26%	2497
	21st to end	Night	16% 3 3 11% 31% 36%	1934
March	1st to 10th	Night	13% 2 3 8% 38% 36%	5050
	11th to 20th	Night	16% 3 3 16% 34% 28%	5110
	21st to end	Night	17% 2 3 16% 33% 28%	5610
April	1st to 10th	Night	13% 2 3 12% 35% 35%	2153
	11th to 20th	Night	15% 2 2 8% 28% 45%	2077
	21st to end	Night	11% 2 2 11% 30% 44%	2100
May	1st to 10th	Night	16% 2 4 12% 21% 44%	5888
	11th to 20th	Night	11% 2 4 8% 29% 46%	5564
	21st to end	Night	12% 1 3 5% 14% 65%	5838
June	1st to 10th	Night	18% 3 3 11% 24% 41%	1890
	11th to 20th	Night	15% 2 3 7% 20% 54%	1890
	21st to end	Night	27% 5% 7% 15% 15% 31%	1890
July	1st to 10th	Night	28% 6% 13% 16% 21% 17%	5295
	11th to 20th	Night	33% 9% 19% 19% 16% 4	5286
	21st to end	Night	38% 7% 17% 21% 9% 8%	5677
August	1st to 10th	Night	36% 8% 14% 27% 12% 4	4212
	11th to 20th	Night	28% 7% 16% 19% 24% 6%	4613
	21st to end	Night	37% 7% 13% 17% 19% 9%	5069
September	1st to 10th	Night	32% 6% 10% 18% 17% 16%	2100
	11th to 20th	Night	24% 5% 8% 19% 24% 20%	2089
	21st to end	Night	17% 4 7% 16% 30% 26%	2266
October	1st to 10th	Night	13% 2 5% 9% 26% 45%	3920
	11th to 20th	Night	15% 1 4 13% 26% 41%	3898
	21st to end	Night	8% 1 2 10% 31% 49%	4252
November	1st to 10th	Night	12% 2 3 15% 35% 33%	2460
	11th to 20th	Night	15% 2 3 17% 32% 32%	2520
	21st to end	Night	21% 2 3 18% 32% 23%	2520
December	1st to 10th	Night	14% 2 3 22% 39% 19%	4304
	11th to 20th	Night	19% 3 5% 12% 34% 27%	4941
	21st to end	Night	16% 2 3 18% 39% 22%	6611

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	12% 8% 27% 36% 14% 3	330
	11th to 20th	Day	5% 7% 27% 39% 18% 5%	330
	21st to end	Day	6% 7% 29% 36% 16% 7%	363
February	1st to 10th	Day	3 10% 28% 34% 22% 4	330
	11th to 20th	Day	12% 11% 29% 36% 12% 2	330
	21st to end	Day	8% 25% 34% 23% 8% 2	411
March	1st to 10th	Day	9% 19% 34% 27% 9% 1	540
	11th to 20th	Day	10% 16% 28% 31% 12% 3	540
	21st to end	Day	7% 20% 33% 27% 10% 2	594
April	1st to 10th	Day	6% 15% 33% 28% 13% 4	540
	11th to 20th	Day	7% 19% 33% 26% 13% 2	532
	21st to end	Day	5% 15% 36% 26% 14% 2	540
May	1st to 10th	Day	3 13% 36% 31% 14% 3	543
	11th to 20th	Day	3 11% 30% 33% 20% 4	568
	21st to end	Day	2 8% 31% 36% 19% 3	617
June	1st to 10th	Day	5% 4 23% 38% 24% 6%	570
	11th to 20th	Day	2 4 23% 39% 24% 8%	570
	21st to end	Day	3 2 13% 39% 30% 13%	570
July	1st to 10th	Day	5% 1 6% 30% 35% 23%	566
	11th to 20th	Day	5% 1 3 24% 38% 28%	564
	21st to end	Day	4 1 3 19% 44% 28%	619
August	1st to 10th	Day	4 2 3 20% 40% 31%	567
	11th to 20th	Day	4 3 6% 23% 40% 25%	557
	21st to end	Day	4 2 6% 23% 39% 27%	627
September	1st to 10th	Day	9% 2 6% 31% 35% 18%	570
	11th to 20th	Day	5% 2 10% 33% 36% 15%	543
	21st to end	Day	3 4 15% 38% 30% 10%	462
October	1st to 10th	Day	6% 4 15% 33% 29% 12%	330
	11th to 20th	Day	8% 5% 17% 33% 29% 8%	330
	21st to end	Day	3 5% 18% 33% 29% 12%	363
November	1st to 10th	Day	5% 4 26% 35% 23% 7%	330
	11th to 20th	Day	4 5% 18% 38% 27% 7%	330
	21st to end	Day	7% 11% 23% 36% 19% 4	330
December	1st to 10th	Day	5% 7% 24% 36% 23% 5%	330
	11th to 20th	Day	8% 6% 27% 33% 22% 5%	330
	21st to end	Day	8% 8% 29% 33% 17% 4	363
January	1st to 10th	Night	6% 5% 28% 41% 16% 4	840
	11th to 20th	Night	5% 3 30% 41% 17% 4	840
	21st to end	Night	9% 5% 28% 42% 14% 3	924
February	1st to 10th	Night	4 6% 33% 40% 15% 3	840
	11th to 20th	Night	7% 7% 35% 38% 11% 1	824
	21st to end	Night	5% 8% 45% 34% 8% 1	692
March	1st to 10th	Night	5% 9% 41% 35% 9% 1	840
	11th to 20th	Night	7% 7% 33% 38% 13% 2	840
	21st to end	Night	4 8% 37% 39% 12% 1	924
April	1st to 10th	Night	2 8% 41% 40% 8% 1	683
	11th to 20th	Night	3 9% 43% 34% 10% 1	623
	21st to end	Night	1 12% 42% 35% 9% 1	630
May	1st to 10th	Night	3 7% 38% 44% 6% 1	630
	11th to 20th	Night	3 5% 33% 44% 14% 1	621
	21st to end	Night	3 5% 33% 48% 11%	683
June	1st to 10th	Night	5% 2 23% 52% 17% 1	630
	11th to 20th	Night	2 3 24% 54% 16% 1	630
	21st to end	Night	6% 2 13% 47% 31% 1	630
July	1st to 10th	Night	6% 2 6% 41% 41% 4	615
	11th to 20th	Night	3 2 4 32% 52% 7%	612
	21st to end	Night	6% 1 2 28% 53% 9%	690
August	1st to 10th	Night	4 2 2 26% 55% 11%	627
	11th to 20th	Night	5% 2 4 32% 49% 8%	624
	21st to end	Night	5% 1 3 30% 54% 7%	693
September	1st to 10th	Night	6% 2 4 37% 49% 2	630
	11th to 20th	Night	6% 1 6% 46% 36% 4	668
	21st to end	Night	4 1 11% 46% 33% 5%	800
October	1st to 10th	Night	6% 2 16% 49% 24% 3	800
	11th to 20th	Night	5% 2 18% 50% 21% 4	800
	21st to end	Night	2 3 20% 43% 24% 7%	880
November	1st to 10th	Night	3 2 20% 43% 25% 7%	820
	11th to 20th	Night	4 3 21% 44% 24% 3	840
	21st to end	Night	7% 4 26% 41% 18% 5%	840
December	1st to 10th	Night	5% 3 26% 44% 18% 3	840
	11th to 20th	Night	5% 4 27% 46% 15% 3	840
	21st to end	Night	8% 6% 27% 41% 15% 3	924

Page generated at 2026-09-11 02:11:51. Version ac07

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