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 2025-05-11.

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 3 1 3 3 3 3 3 5% 6% 67%	118267
	Night	3 3 1 3 3 3 3 3 5% 7% 66%	119586
Transparency	Day	17% 3 5% 14% 29% 31%	118031
	Night	19% 3 5% 14% 29% 29%	119411
Seeing	Day	6% 8% 21% 31% 24% 10%	15113
	Night	5% 4 24% 40% 23% 4	25198

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 3 2 4 5% 64%	4098
	11th to 20th	Day	2 2 1 1 2 2 2 4 5% 78%	4100
	21st to end	Day	5% 3 1 3 2 2 3 3 5% 6% 66%	4510
February	1st to 10th	Day	3 3 1 4 2 2 3 3 4 6% 69%	1800
	11th to 20th	Day	5% 3 1 3 3 3 4 3 3 6% 66%	1909
	21st to end	Day	4 4 1 2 3 2 3 2 4 5% 70%	1781
March	1st to 10th	Day	2 3 1 4 3 3 3 2 4 6% 70%	4954
	11th to 20th	Day	5% 3 1 3 2 3 3 3 4 6% 67%	5000
	21st to end	Day	2 3 1 4 3 4 4 3 5% 7% 64%	5486
April	1st to 10th	Day	1 2 1 3 2 2 2 3 4 6% 74%	2349
	11th to 20th	Day	3 2 1 2 2 2 2 1 2 4 79%	2371
	21st to end	Day	2 2 1 2 1 1 2 3 5% 81%	2400
May	1st to 10th	Day	1 1 1 1 1 2 2 3 3 85%	3920
	11th to 20th	Day	1 1 3 2 2 2 2 4 4 78%	3916
	21st to end	Day	1 1 1 1 1 1 1 2 3 88%	4477
June	1st to 10th	Day	3 2 1 3 3 3 3 3 4 7% 68%	2470
	11th to 20th	Day	2 2 1 2 2 2 3 3 4 5% 75%	2470
	21st to end	Day	5% 3 1 4 4 4 5% 4 7% 8% 56%	2470
July	1st to 10th	Day	3 3 1 3 4 4 4 4 7% 8% 58%	4110
	11th to 20th	Day	3 2 1 4 4 5% 5% 4 8% 10% 53%	4110
	21st to end	Day	4 4 2 6% 5% 7% 8% 7% 10% 12% 35%	4454
August	1st to 10th	Day	3 3 2 5% 5% 5% 5% 5% 8% 10% 50%	4049
	11th to 20th	Day	3 2 1 4 3 4 4 4 6% 9% 59%	3726
	21st to end	Day	4 3 1 5% 5% 5% 6% 6% 8% 11% 46%	4180
September	1st to 10th	Day	8% 4 2 5% 5% 4 5% 4 7% 8% 50%	2280
	11th to 20th	Day	6% 3 1 4 2 3 4 3 5% 7% 62%	2218
	21st to end	Day	3 2 1 3 2 2 2 3 4 6% 71%	2026
October	1st to 10th	Day	2 1 1 2 2 1 2 2 4 5% 78%	3170
	11th to 20th	Day	3 2 1 3 2 2 2 2 3 4 75%	3150
	21st to end	Day	1 1 1 1 1 1 2 2 3 86%	3438
November	1st to 10th	Day	2 2 1 3 3 2 3 2 4 6% 73%	1959
	11th to 20th	Day	2 3 1 3 2 3 3 3 4 5% 72%	2000
	21st to end	Day	5% 4 1 4 3 3 3 3 4 6% 63%	2000
December	1st to 10th	Day	6% 3 1 3 3 2 3 2 4 5% 67%	2997
	11th to 20th	Day	3 4 2 4 3 2 3 2 3 7% 68%	3409
	21st to end	Day	2 2 1 2 2 3 3 3 4 7% 72%	4510
January	1st to 10th	Night	4 6% 2 4 3 3 3 3 4 6% 62%	5867
	11th to 20th	Night	2 1 2 2 2 2 2 3 4 79%	5880
	21st to end	Night	7% 4 1 3 2 2 3 3 5% 6% 63%	6468
February	1st to 10th	Night	3 2 1 3 3 2 4 3 4 7% 69%	2600
	11th to 20th	Night	5% 5% 1 3 3 2 3 3 3 6% 67%	2375
	21st to end	Night	4 3 1 3 2 3 3 3 5% 6% 68%	1845
March	1st to 10th	Night	2 2 1 2 2 2 3 3 5% 5% 73%	4940
	11th to 20th	Night	6% 3 1 3 2 2 3 3 5% 5% 68%	5000
	21st to end	Night	1 2 1 3 2 3 3 3 5% 7% 68%	5489
April	1st to 10th	Night	1 2 1 2 2 2 2 2 4 6% 74%	2050
	11th to 20th	Night	2 2 1 3 3 2 2 2 4 5% 74%	1977
	21st to end	Night	2 1 2 2 2 3 3 3 4 78%	2000
May	1st to 10th	Night	2 1 1 1 2 1 1 3 4 83%	3270
	11th to 20th	Night	2 1 1 3 2 3 3 2 3 5% 73%	2978
	21st to end	Night	1 1 2 1 1 1 1 2 3 85%	3110
June	1st to 10th	Night	4 2 1 4 2 3 3 4 4 6% 67%	1710
	11th to 20th	Night	2 2 1 2 3 3 3 2 5% 5% 72%	1710
	21st to end	Night	5% 4 1 5% 5% 5% 6% 5% 8% 8% 50%	1710
July	1st to 10th	Night	3 3 1 5% 4 5% 6% 6% 10% 12% 45%	2860
	11th to 20th	Night	3 2 2 6% 5% 6% 8% 6% 9% 13% 41%	2860
	21st to end	Night	4 5% 3 8% 6% 6% 7% 6% 9% 13% 31%	3109
August	1st to 10th	Night	3 3 2 7% 5% 7% 8% 7% 9% 15% 35%	2877
	11th to 20th	Night	4 4 2 5% 5% 6% 7% 5% 8% 14% 40%	3113
	21st to end	Night	4 5% 3 9% 7% 7% 8% 6% 9% 10% 32%	3487
September	1st to 10th	Night	6% 4 2 6% 4 5% 6% 4 6% 7% 50%	1900
	11th to 20th	Night	5% 3 1 4 4 4 4 4 6% 8% 59%	1956
	21st to end	Night	3 2 1 3 2 3 3 2 4 5% 71%	2152
October	1st to 10th	Night	3 1 1 2 2 2 2 2 4 6% 75%	3800
	11th to 20th	Night	3 2 1 3 2 2 2 2 3 5% 75%	3778
	21st to end	Night	2 1 1 1 1 2 1 3 5% 83%	4120
November	1st to 10th	Night	2 1 1 2 2 2 3 3 4 5% 75%	2340
	11th to 20th	Night	3 2 1 3 2 2 2 3 4 6% 74%	2400
	21st to end	Night	6% 3 1 4 3 3 3 3 5% 6% 65%	2400
December	1st to 10th	Night	4 2 1 3 2 2 2 2 4 5% 74%	4176
	11th to 20th	Night	2 2 1 4 3 3 4 3 5% 6% 66%	4811
	21st to end	Night	4 3 1 3 2 2 2 2 4 5% 71%	6468

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	21% 4 2 10% 42% 20%	4099
	11th to 20th	Day	9% 3 3 14% 44% 27%	4100
	21st to end	Day	18% 4 3 17% 31% 27%	4510
February	1st to 10th	Day	17% 3 4 14% 26% 35%	1800
	11th to 20th	Day	21% 2 3 15% 31% 28%	1919
	21st to end	Day	18% 2 2 8% 30% 39%	1781
March	1st to 10th	Day	16% 2 3 6% 34% 40%	4954
	11th to 20th	Day	18% 3 3 15% 29% 32%	5000
	21st to end	Day	19% 3 4 10% 34% 31%	5486
April	1st to 10th	Day	12% 2 2 10% 35% 39%	2349
	11th to 20th	Day	11% 2 1 6% 26% 53%	2374
	21st to end	Day	9% 1 2 9% 31% 49%	2400
May	1st to 10th	Day	7% 1 1 6% 23% 61%	3920
	11th to 20th	Day	9% 3 5% 8% 27% 49%	3919
	21st to end	Day	5% 1 2 5% 14% 73%	4477
June	1st to 10th	Day	16% 3 2 10% 27% 42%	2470
	11th to 20th	Day	11% 3 2 6% 19% 60%	2470
	21st to end	Day	23% 5% 6% 15% 19% 31%	2470
July	1st to 10th	Day	20% 5% 12% 15% 20% 27%	4046
	11th to 20th	Day	22% 6% 11% 24% 29% 8%	4041
	21st to end	Day	32% 10% 17% 28% 11% 2	4314
August	1st to 10th	Day	25% 6% 12% 29% 23% 5%	4035
	11th to 20th	Day	20% 6% 9% 18% 34% 13%	3762
	21st to end	Day	27% 8% 14% 22% 20% 9%	4179
September	1st to 10th	Day	29% 4 9% 18% 23% 17%	2280
	11th to 20th	Day	21% 4 6% 17% 28% 24%	2218
	21st to end	Day	15% 3 4 16% 34% 28%	2026
October	1st to 10th	Day	11% 2 4 10% 24% 49%	3170
	11th to 20th	Day	15% 2 4 11% 31% 38%	3150
	21st to end	Day	7% 1 1 10% 32% 49%	3438
November	1st to 10th	Day	14% 2 4 17% 35% 29%	1959
	11th to 20th	Day	16% 2 3 16% 30% 32%	2000
	21st to end	Day	22% 3 4 17% 30% 23%	2000
December	1st to 10th	Day	20% 3 3 18% 35% 21%	2997
	11th to 20th	Day	21% 2 3 14% 38% 22%	3408
	21st to end	Day	13% 2 5% 17% 40% 22%	4510
January	1st to 10th	Night	23% 2 3 11% 43% 17%	5867
	11th to 20th	Night	11% 2 2 15% 45% 25%	5880
	21st to end	Night	23% 3 4 15% 27% 28%	6468
February	1st to 10th	Night	16% 3 4 17% 26% 34%	2600
	11th to 20th	Night	20% 2 3 16% 31% 27%	2375
	21st to end	Night	16% 3 3 10% 29% 37%	1845
March	1st to 10th	Night	13% 2 3 8% 39% 35%	4940
	11th to 20th	Night	17% 3 3 16% 34% 28%	5000
	21st to end	Night	17% 2 3 16% 34% 27%	5489
April	1st to 10th	Night	13% 2 3 12% 35% 36%	2050
	11th to 20th	Night	15% 2 2 8% 28% 46%	1977
	21st to end	Night	11% 2 2 11% 30% 45%	2000
May	1st to 10th	Night	9% 1 1 6% 24% 60%	3270
	11th to 20th	Night	12% 3 5% 8% 21% 50%	2979
	21st to end	Night	7% 1 1 4 16% 70%	3110
June	1st to 10th	Night	18% 4 3 11% 25% 40%	1710
	11th to 20th	Night	14% 2 2 7% 20% 54%	1710
	21st to end	Night	28% 6% 7% 15% 15% 30%	1710
July	1st to 10th	Night	26% 7% 15% 17% 18% 17%	2815
	11th to 20th	Night	29% 7% 13% 23% 21% 7%	2806
	21st to end	Night	40% 8% 19% 24% 7% 2	3011
August	1st to 10th	Night	33% 8% 16% 28% 11% 5%	2868
	11th to 20th	Night	30% 6% 12% 13% 30% 8%	3143
	21st to end	Night	41% 8% 15% 17% 14% 4	3487
September	1st to 10th	Night	31% 6% 9% 19% 18% 18%	1900
	11th to 20th	Night	23% 5% 8% 18% 25% 21%	1956
	21st to end	Night	16% 4 7% 16% 31% 26%	2152
October	1st to 10th	Night	12% 2 5% 9% 26% 46%	3800
	11th to 20th	Night	14% 1 4 13% 27% 42%	3778
	21st to end	Night	8% 1 2 10% 31% 49%	4120
November	1st to 10th	Night	12% 2 4 16% 35% 32%	2340
	11th to 20th	Night	14% 2 3 17% 32% 33%	2400
	21st to end	Night	22% 3 4 17% 30% 24%	2400
December	1st to 10th	Night	15% 2 3 22% 39% 19%	4176
	11th to 20th	Night	19% 3 5% 13% 34% 27%	4811
	21st to end	Night	16% 2 2 18% 40% 22%	6468

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% 37% 14% 3	300
	11th to 20th	Day	6% 8% 28% 37% 17% 4	300
	21st to end	Day	5% 8% 30% 35% 16% 7%	330
February	1st to 10th	Day	4 11% 27% 34% 20% 4	300
	11th to 20th	Day	11% 10% 30% 36% 12% 2	300
	21st to end	Day	9% 27% 34% 22% 8% 2	380
March	1st to 10th	Day	10% 20% 33% 28% 9% 1	500
	11th to 20th	Day	11% 16% 28% 30% 11% 3	500
	21st to end	Day	8% 22% 35% 26% 9% 1	550
April	1st to 10th	Day	6% 16% 33% 28% 13% 4	500
	11th to 20th	Day	7% 19% 32% 26% 13% 2	492
	21st to end	Day	5% 14% 36% 28% 15% 2	500
May	1st to 10th	Day	4 13% 35% 30% 15% 3	503
	11th to 20th	Day	3 9% 28% 34% 21% 4	489
	21st to end	Day	2 8% 33% 36% 18% 3	529
June	1st to 10th	Day	5% 5% 21% 38% 24% 6%	490
	11th to 20th	Day	3 4 23% 39% 25% 7%	490
	21st to end	Day	4 3 11% 40% 31% 12%	490
July	1st to 10th	Day	6% 1 5% 30% 34% 24%	486
	11th to 20th	Day	6% 1 3 22% 39% 29%	484
	21st to end	Day	5% 1 3 17% 45% 29%	531
August	1st to 10th	Day	5% 2 2 20% 39% 32%	487
	11th to 20th	Day	4 3 5% 23% 41% 23%	477
	21st to end	Day	4 2 6% 22% 38% 28%	539
September	1st to 10th	Day	10% 2 6% 32% 36% 16%	490
	11th to 20th	Day	5% 1 11% 32% 36% 14%	490
	21st to end	Day	4 4 15% 37% 31% 10%	426
October	1st to 10th	Day	6% 3 15% 32% 30% 13%	300
	11th to 20th	Day	7% 6% 17% 32% 30% 8%	300
	21st to end	Day	4 5% 17% 32% 28% 14%	330
November	1st to 10th	Day	6% 5% 28% 35% 21% 5%	300
	11th to 20th	Day	4 6% 18% 39% 27% 7%	300
	21st to end	Day	8% 11% 23% 35% 18% 4	300
December	1st to 10th	Day	6% 7% 24% 36% 23% 4	300
	11th to 20th	Day	8% 7% 28% 33% 21% 4	300
	21st to end	Day	8% 9% 30% 34% 15% 4	330
January	1st to 10th	Night	6% 5% 28% 41% 17% 4	800
	11th to 20th	Night	6% 3 31% 39% 18% 4	800
	21st to end	Night	9% 5% 28% 40% 14% 3	880
February	1st to 10th	Night	4 6% 33% 39% 15% 4	800
	11th to 20th	Night	7% 7% 34% 39% 11% 2	784
	21st to end	Night	5% 8% 45% 32% 8% 1	660
March	1st to 10th	Night	6% 9% 41% 34% 9% 1	800
	11th to 20th	Night	7% 7% 33% 38% 13% 2	800
	21st to end	Night	4 8% 38% 38% 11% 1	880
April	1st to 10th	Night	2 8% 42% 39% 8% 1	650
	11th to 20th	Night	3 9% 43% 33% 11% 1	593
	21st to end	Night	1 12% 40% 36% 9% 1	600
May	1st to 10th	Night	4 6% 38% 45% 7% 1	600
	11th to 20th	Night	4 4 32% 45% 14% 1	563
	21st to end	Night	3 5% 35% 46% 11%	617
June	1st to 10th	Night	5% 2 22% 52% 18% 1	570
	11th to 20th	Night	2 3 24% 53% 17% 1	570
	21st to end	Night	6% 2 13% 46% 32% 1	570
July	1st to 10th	Night	6% 2 6% 39% 42% 5%	555
	11th to 20th	Night	3 2 3 31% 53% 8%	552
	21st to end	Night	6% 1 2 27% 54% 10%	624
August	1st to 10th	Night	4 2 2 24% 56% 12%	567
	11th to 20th	Night	5% 2 4 31% 49% 9%	564
	21st to end	Night	5% 1 3 29% 54% 8%	627
September	1st to 10th	Night	6% 2 4 37% 49% 2	570
	11th to 20th	Night	6% 1 6% 46% 37% 4	626
	21st to end	Night	4 1 12% 45% 33% 5%	760
October	1st to 10th	Night	6% 2 16% 48% 25% 3	760
	11th to 20th	Night	4 2 18% 50% 22% 4	760
	21st to end	Night	3 3 20% 43% 25% 7%	836
November	1st to 10th	Night	3 2 20% 43% 24% 7%	780
	11th to 20th	Night	3 3 22% 43% 25% 3	800
	21st to end	Night	8% 4 25% 40% 18% 5%	800
December	1st to 10th	Night	6% 3 26% 44% 18% 3	800
	11th to 20th	Night	5% 4 28% 45% 15% 3	800
	21st to end	Night	8% 6% 27% 41% 15% 3	880

Page generated at 2025-05-08 07:33:58. Version ac07

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