White Sands National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the White Sands National Park clear sky chart from 2005-11-06 to 2024-10-25.

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 3 3 5% 7% 66%	100246
	Night	4 3 1 4 3 3 4 3 5% 7% 62%	98747
Transparency	Day	16% 5% 8% 17% 28% 26%	100009
	Night	19% 5% 8% 15% 27% 26%	98574
Seeing	Day	4 5% 17% 29% 29% 16%	14420
	Night	5% 3 21% 45% 25% 2	24804

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 5% 2 4 3 3 3 3 5% 6% 63%	2858
	11th to 20th	Day	2 2 1 2 2 2 2 2 3 7% 75%	2860
	21st to end	Day	8% 5% 1 4 3 2 4 3 6% 8% 56%	3146
February	1st to 10th	Day	3 3 1 3 2 3 2 2 4 6% 70%	1813
	11th to 20th	Day	5% 4 1 2 3 3 3 3 3 4 68%	1849
	21st to end	Day	3 2 1 3 3 2 3 3 3 4 72%	1570
March	1st to 10th	Day	3 4 1 3 3 3 3 2 3 6% 68%	3380
	11th to 20th	Day	4 4 1 4 3 3 4 3 5% 5% 63%	3490
	21st to end	Day	2 4 1 4 3 3 4 4 6% 8% 62%	3913
April	1st to 10th	Day	2 2 1 2 3 2 3 3 5% 6% 73%	2280
	11th to 20th	Day	2 2 1 2 2 2 2 2 3 4 77%	2251
	21st to end	Day	2 2 1 1 2 2 2 2 3 5% 79%	2280
May	1st to 10th	Day	1 1 1 1 2 2 2 2 3 84%	3800
	11th to 20th	Day	1 1 1 2 2 2 3 3 5% 6% 74%	3765
	21st to end	Day	1 1 1 1 1 1 1 2 3 88%	4351
June	1st to 10th	Day	2 2 1 2 2 3 3 2 5% 7% 69%	2570
	11th to 20th	Day	2 1 1 2 2 2 3 2 4 5% 77%	2611
	21st to end	Day	4 3 1 4 4 4 4 4 7% 8% 59%	2470
July	1st to 10th	Day	3 3 1 4 4 4 5% 6% 8% 10% 52%	4110
	11th to 20th	Day	2 1 1 3 3 4 4 4 7% 11% 61%	4110
	21st to end	Day	4 3 1 4 4 4 6% 5% 9% 13% 46%	4454
August	1st to 10th	Day	2 2 1 3 3 4 5% 5% 8% 12% 53%	3829
	11th to 20th	Day	3 2 1 3 3 3 3 4 6% 9% 64%	3726
	21st to end	Day	2 2 1 4 4 5% 6% 6% 8% 11% 52%	4180
September	1st to 10th	Day	6% 4 2 4 4 4 5% 4 5% 7% 56%	2280
	11th to 20th	Day	6% 2 1 3 3 3 4 4 4 7% 63%	2280
	21st to end	Day	3 2 1 2 2 3 2 1 3 7% 73%	2072
October	1st to 10th	Day	3 2 1 4 2 2 3 3 5% 6% 68%	1900
	11th to 20th	Day	4 2 1 3 2 2 2 2 3 5% 74%	1900
	21st to end	Day	2 1 1 2 2 1 2 2 3 4 80%	2025
November	1st to 10th	Day	2 2 1 2 1 2 2 2 4 5% 76%	1859
	11th to 20th	Day	2 2 1 3 2 3 3 2 5% 5% 73%	1815
	21st to end	Day	6% 3 1 3 2 3 3 4 5% 6% 63%	1710
December	1st to 10th	Day	5% 4 1 3 2 2 3 2 4 8% 65%	1702
	11th to 20th	Day	4 4 2 5% 4 3 3 3 4 7% 60%	1926
	21st to end	Day	5% 3 1 3 3 3 3 3 5% 7% 65%	3111
January	1st to 10th	Night	4 6% 2 4 3 4 3 3 5% 5% 61%	4097
	11th to 20th	Night	3 3 1 2 2 2 2 2 4 7% 72%	4110
	21st to end	Night	8% 5% 1 4 4 3 3 4 5% 7% 55%	4521
February	1st to 10th	Night	4 3 1 2 3 3 3 3 5% 6% 68%	2364
	11th to 20th	Night	8% 4 1 3 3 3 3 2 4 5% 64%	2218
	21st to end	Night	4 3 1 3 3 3 3 3 5% 7% 65%	1884
March	1st to 10th	Night	5% 6% 1 3 2 2 2 2 4 7% 65%	3488
	11th to 20th	Night	8% 4 2 4 3 3 3 3 4 6% 59%	3490
	21st to end	Night	4 5% 2 4 3 3 4 3 4 7% 60%	3734
April	1st to 10th	Night	1 3 1 2 3 3 3 3 5% 6% 69%	1900
	11th to 20th	Night	4 3 2 3 3 2 3 3 4 5% 68%	1877
	21st to end	Night	3 2 1 3 2 2 2 3 5% 5% 72%	1900
May	1st to 10th	Night	2 1 1 1 1 2 2 2 2 4 82%	3170
	11th to 20th	Night	2 2 1 3 3 3 4 3 5% 7% 69%	3140
	21st to end	Night	1 1 2 1 2 1 2 2 3 83%	3218
June	1st to 10th	Night	3 2 1 3 4 5% 4 4 7% 6% 61%	1594
	11th to 20th	Night	3 1 2 2 2 3 3 5% 6% 71%	1552
	21st to end	Night	4 3 1 4 5% 5% 4 5% 9% 9% 50%	1710
July	1st to 10th	Night	2 3 2 5% 5% 6% 7% 6% 8% 10% 46%	2860
	11th to 20th	Night	2 2 1 5% 5% 5% 6% 5% 7% 11% 51%	2860
	21st to end	Night	4 5% 2 6% 6% 6% 8% 7% 9% 11% 35%	3109
August	1st to 10th	Night	3 2 1 4 4 5% 6% 6% 9% 15% 44%	3094
	11th to 20th	Night	3 2 1 4 3 4 5% 5% 8% 11% 55%	3113
	21st to end	Night	4 4 2 7% 5% 6% 7% 6% 9% 11% 38%	3487
September	1st to 10th	Night	5% 3 2 5% 4 4 5% 5% 6% 9% 52%	1900
	11th to 20th	Night	7% 4 1 4 3 4 3 3 5% 8% 57%	1900
	21st to end	Night	4 2 1 3 2 3 4 3 4 6% 68%	2104
October	1st to 10th	Night	4 3 1 4 3 3 3 3 5% 7% 64%	2280
	11th to 20th	Night	4 2 1 2 3 2 2 2 3 4 75%	2280
	21st to end	Night	4 2 1 2 2 2 2 1 3 4 78%	2436
November	1st to 10th	Night	2 1 1 2 2 2 3 2 4 7% 75%	2220
	11th to 20th	Night	2 2 1 2 1 3 3 2 4 6% 74%	2341
	21st to end	Night	6% 3 1 4 2 2 3 3 4 6% 64%	2470
December	1st to 10th	Night	7% 3 1 3 2 3 3 3 4 7% 65%	2474
	11th to 20th	Night	4 3 1 5% 3 3 4 3 5% 7% 60%	3271
	21st to end	Night	6% 3 1 3 2 3 4 3 4 6% 65%	4581

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	18% 5% 8% 15% 41% 14%	2859
	11th to 20th	Day	12% 3 6% 19% 45% 15%	2860
	21st to end	Day	22% 6% 9% 24% 27% 12%	3146
February	1st to 10th	Day	16% 3 5% 18% 30% 28%	1813
	11th to 20th	Day	20% 3 5% 15% 32% 25%	1859
	21st to end	Day	16% 3 4 8% 32% 37%	1570
March	1st to 10th	Day	17% 3 5% 10% 35% 31%	3380
	11th to 20th	Day	19% 6% 7% 18% 27% 24%	3490
	21st to end	Day	15% 6% 8% 14% 31% 27%	3913
April	1st to 10th	Day	12% 3 5% 11% 31% 40%	2280
	11th to 20th	Day	12% 2 4 9% 24% 49%	2254
	21st to end	Day	9% 3 4 11% 29% 44%	2280
May	1st to 10th	Day	7% 2 2 6% 19% 64%	3800
	11th to 20th	Day	9% 5% 7% 12% 24% 43%	3768
	21st to end	Day	5% 1 3 7% 15% 69%	4351
June	1st to 10th	Day	13% 4 8% 14% 25% 36%	2570
	11th to 20th	Day	9% 3 5% 8% 23% 52%	2611
	21st to end	Day	20% 6% 10% 15% 22% 27%	2470
July	1st to 10th	Day	22% 7% 15% 19% 18% 20%	4046
	11th to 20th	Day	15% 7% 14% 28% 30% 7%	4041
	21st to end	Day	23% 9% 16% 29% 19% 3	4314
August	1st to 10th	Day	19% 7% 11% 31% 27% 5%	3815
	11th to 20th	Day	16% 6% 12% 18% 37% 11%	3762
	21st to end	Day	21% 8% 16% 26% 23% 6%	4179
September	1st to 10th	Day	24% 7% 10% 20% 22% 16%	2280
	11th to 20th	Day	20% 6% 8% 18% 27% 21%	2280
	21st to end	Day	13% 3 7% 18% 33% 25%	2072
October	1st to 10th	Day	17% 5% 7% 14% 27% 30%	1900
	11th to 20th	Day	15% 3 5% 10% 30% 37%	1900
	21st to end	Day	10% 2 3 19% 33% 33%	2025
November	1st to 10th	Day	11% 2 6% 19% 34% 28%	1859
	11th to 20th	Day	13% 3 7% 19% 30% 28%	1815
	21st to end	Day	20% 4 7% 15% 35% 20%	1710
December	1st to 10th	Day	19% 4 6% 23% 34% 14%	1702
	11th to 20th	Day	24% 4 9% 21% 31% 11%	1924
	21st to end	Day	16% 4 8% 20% 35% 18%	3111
January	1st to 10th	Night	20% 6% 7% 15% 38% 15%	4097
	11th to 20th	Night	13% 3 7% 16% 46% 15%	4110
	21st to end	Night	24% 6% 8% 19% 30% 12%	4521
February	1st to 10th	Night	17% 3 7% 16% 25% 31%	2364
	11th to 20th	Night	21% 4 6% 11% 29% 29%	2218
	21st to end	Night	16% 3 6% 9% 27% 37%	1884
March	1st to 10th	Night	18% 4 6% 10% 33% 30%	3488
	11th to 20th	Night	21% 8% 9% 15% 25% 23%	3490
	21st to end	Night	18% 6% 7% 11% 33% 25%	3734
April	1st to 10th	Night	14% 3 6% 10% 30% 38%	1900
	11th to 20th	Night	17% 3 6% 11% 20% 43%	1877
	21st to end	Night	12% 4 5% 12% 26% 42%	1900
May	1st to 10th	Night	8% 2 3 6% 16% 65%	3170
	11th to 20th	Night	11% 6% 9% 11% 20% 43%	3141
	21st to end	Night	9% 2 3 6% 13% 67%	3219
June	1st to 10th	Night	19% 7% 8% 15% 18% 35%	1594
	11th to 20th	Night	12% 3 6% 11% 16% 51%	1552
	21st to end	Night	24% 7% 12% 17% 17% 22%	1710
July	1st to 10th	Night	28% 9% 14% 18% 15% 15%	2815
	11th to 20th	Night	23% 6% 13% 20% 29% 9%	2806
	21st to end	Night	34% 10% 16% 26% 11% 3	3011
August	1st to 10th	Night	23% 8% 13% 27% 24% 6%	3085
	11th to 20th	Night	19% 6% 12% 18% 32% 13%	3143
	21st to end	Night	33% 8% 14% 21% 18% 5%	3487
September	1st to 10th	Night	26% 7% 13% 15% 21% 18%	1900
	11th to 20th	Night	24% 5% 10% 17% 21% 22%	1900
	21st to end	Night	17% 4 9% 15% 29% 26%	2104
October	1st to 10th	Night	19% 6% 8% 13% 23% 31%	2280
	11th to 20th	Night	15% 3 5% 11% 23% 44%	2280
	21st to end	Night	13% 2 4 14% 30% 37%	2436
November	1st to 10th	Night	11% 3 4 15% 34% 33%	2220
	11th to 20th	Night	12% 3 5% 16% 31% 32%	2341
	21st to end	Night	20% 4 6% 15% 32% 23%	2470
December	1st to 10th	Night	19% 4 7% 19% 31% 21%	2474
	11th to 20th	Night	21% 5% 9% 20% 31% 14%	3272
	21st to end	Night	18% 3 7% 18% 40% 13%	4581

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	8% 6% 19% 41% 22% 5%	270
	11th to 20th	Day	5% 4 19% 41% 25% 7%	270
	21st to end	Day	4 4 25% 34% 28% 6%	297
February	1st to 10th	Day	5% 7% 23% 36% 22% 7%	270
	11th to 20th	Day	12% 6% 22% 43% 15% 2	270
	21st to end	Day	5% 12% 27% 42% 11% 3	225
March	1st to 10th	Day	5% 12% 31% 36% 13% 2	418
	11th to 20th	Day	7% 13% 25% 33% 18% 5%	460
	21st to end	Day	4 19% 31% 31% 12% 3	506
April	1st to 10th	Day	4 12% 29% 35% 17% 3	460
	11th to 20th	Day	3 17% 33% 31% 14% 2	452
	21st to end	Day	3 12% 34% 29% 17% 4	460
May	1st to 10th	Day	2 9% 33% 30% 20% 5%	463
	11th to 20th	Day	1 7% 24% 36% 24% 8%	488
	21st to end	Day	2 6% 29% 37% 23% 3	529
June	1st to 10th	Day	3 3 14% 34% 36% 11%	590
	11th to 20th	Day	3 2 13% 35% 38% 9%	631
	21st to end	Day	3 1 8% 31% 34% 23%	490
July	1st to 10th	Day	3 1 5% 19% 44% 29%	486
	11th to 20th	Day	2 2 16% 39% 41%	484
	21st to end	Day	3 2 18% 34% 43%	531
August	1st to 10th	Day	2 1 16% 35% 45%	487
	11th to 20th	Day	5% 1 5% 15% 41% 33%	477
	21st to end	Day	3 1 3 15% 38% 40%	539
September	1st to 10th	Day	6% 6% 22% 39% 27%	490
	11th to 20th	Day	5% 6% 23% 44% 21%	490
	21st to end	Day	3 3 8% 24% 38% 24%	329
October	1st to 10th	Day	5% 3 11% 24% 32% 25%	300
	11th to 20th	Day	6% 3 11% 26% 32% 21%	300
	21st to end	Day	5% 5% 15% 23% 32% 19%	311
November	1st to 10th	Day	4 4 18% 30% 32% 11%	270
	11th to 20th	Day	1 3 14% 26% 43% 13%	270
	21st to end	Day	7% 6% 24% 34% 24% 6%	270
December	1st to 10th	Day	9% 3 14% 39% 29% 7%	270
	11th to 20th	Day	6% 6% 19% 44% 23% 3	270
	21st to end	Day	8% 5% 23% 43% 18% 3	297
January	1st to 10th	Night	6% 3 22% 50% 18% 1	760
	11th to 20th	Night	6% 4 26% 46% 18% 1	760
	21st to end	Night	6% 3 27% 45% 18% 1	836
February	1st to 10th	Night	5% 3 29% 44% 17% 1	760
	11th to 20th	Night	8% 4 29% 48% 10%	744
	21st to end	Night	4 5% 44% 40% 7%	628
March	1st to 10th	Night	8% 6% 33% 44% 10%	760
	11th to 20th	Night	5% 7% 30% 44% 14% 1	760
	21st to end	Night	4 4 36% 45% 11%	780
April	1st to 10th	Night	1 5% 41% 43% 10%	570
	11th to 20th	Night	5% 7% 38% 41% 9%	563
	21st to end	Night	3 7% 37% 44% 9%	570
May	1st to 10th	Night	4 2 34% 50% 9%	570
	11th to 20th	Night	3 2 23% 56% 16%	561
	21st to end	Night	2 3 28% 54% 13%	617
June	1st to 10th	Night	3 2 18% 54% 23% 1	570
	11th to 20th	Night	2 1 16% 57% 22% 1	570
	21st to end	Night	3 1 9% 50% 34% 2	570
July	1st to 10th	Night	5% 6% 41% 44% 4	555
	11th to 20th	Night	3 5% 33% 54% 6%	552
	21st to end	Night	4 1 3 32% 54% 6%	624
August	1st to 10th	Night	4 1 3 26% 58% 8%	567
	11th to 20th	Night	4 1 3 30% 54% 8%	564
	21st to end	Night	4 5% 32% 53% 5%	627
September	1st to 10th	Night	4 5% 39% 47% 4	570
	11th to 20th	Night	7% 1 5% 44% 41% 1	570
	21st to end	Night	4 1 10% 51% 31% 3	613
October	1st to 10th	Night	4 2 13% 47% 33% 1	760
	11th to 20th	Night	4 2 17% 49% 26% 2	760
	21st to end	Night	4 2 18% 39% 32% 5%	812
November	1st to 10th	Night	3 1 16% 46% 32% 2	740
	11th to 20th	Night	3 1 18% 48% 28% 2	821
	21st to end	Night	7% 3 22% 42% 24% 2	950
December	1st to 10th	Night	8% 3 20% 47% 21% 1	950
	11th to 20th	Night	5% 3 25% 48% 18%	950
	21st to end	Night	5% 4 25% 50% 15% 1	870

Page generated at 2024-10-22 18:21:03. Version ac07

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