Zuni
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Zuni clear sky chart from 2005-11-06 to 2026-01-17.

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 4 2 4 4 4 4 4 5% 7% 60%	136117
	Night	3 5% 2 5% 3 4 4 3 5% 7% 59%	133001
Transparency	Day	23% 3 7% 18% 27% 22%	131020
	Night	25% 3 7% 18% 27% 20%	129101
Seeing	Day	7% 10% 22% 28% 23% 10%	16065
	Night	6% 4 20% 41% 25% 3	26180

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 8% 2 5% 3 3 4 3 5% 5% 58%	4188
	11th to 20th	Day	2 6% 1 3 2 2 3 3 4 5% 69%	4154
	21st to end	Day	3 11% 4 5% 3 4 3 2 4 4 56%	4510
February	1st to 10th	Day	2 8% 3 5% 4 4 3 3 4 7% 59%	1800
	11th to 20th	Day	3 8% 3 6% 4 3 4 4 5% 7% 53%	1785
	21st to end	Day	3 8% 2 6% 3 4 3 3 4 7% 56%	1799
March	1st to 10th	Day	2 6% 2 5% 3 3 3 3 5% 7% 59%	4954
	11th to 20th	Day	3 9% 4 7% 4 5% 5% 4 6% 7% 46%	5000
	21st to end	Day	2 5% 2 5% 4 4 4 3 6% 6% 58%	5486
April	1st to 10th	Day	2 4 2 5% 3 4 3 4 4 7% 63%	2320
	11th to 20th	Day	3 5% 2 4 3 3 3 3 5% 5% 64%	2371
	21st to end	Day	2 3 1 3 3 4 2 3 4 6% 67%	2400
May	1st to 10th	Day	3 3 1 4 3 4 4 3 5% 6% 63%	5704
	11th to 20th	Day	2 3 1 3 3 3 4 4 5% 6% 66%	5841
	21st to end	Day	1 2 1 2 2 2 3 3 4 5% 75%	6423
June	1st to 10th	Day	1 2 1 3 3 3 3 4 5% 7% 68%	2600
	11th to 20th	Day	2 2 1 2 2 2 2 2 4 4 77%	2600
	21st to end	Day	2 2 1 4 4 5% 4 4 6% 6% 62%	2600
July	1st to 10th	Day	2 2 1 4 4 4 4 3 5% 6% 64%	5879
	11th to 20th	Day	2 3 1 5% 5% 6% 7% 6% 8% 11% 45%	5880
	21st to end	Day	3 3 2 6% 5% 6% 6% 5% 7% 9% 47%	6401
August	1st to 10th	Day	3 3 1 6% 5% 6% 6% 5% 7% 9% 49%	5779
	11th to 20th	Day	3 3 2 5% 5% 5% 6% 5% 7% 9% 50%	5623
	21st to end	Day	3 3 2 6% 5% 6% 7% 6% 8% 10% 44%	5984
September	1st to 10th	Day	5% 4 1 6% 5% 5% 5% 4 6% 8% 51%	2400
	11th to 20th	Day	4 3 1 4 3 4 4 3 5% 5% 63%	2256
	21st to end	Day	4 2 1 4 3 3 3 3 4 6% 67%	2175
October	1st to 10th	Day	3 2 1 3 2 2 2 2 3 4 75%	3270
	11th to 20th	Day	4 3 1 4 3 3 4 3 5% 6% 65%	3250
	21st to end	Day	2 2 1 2 1 1 2 2 3 6% 77%	3548
November	1st to 10th	Day	2 3 1 3 3 2 2 3 4 7% 71%	2059
	11th to 20th	Day	2 2 1 3 3 3 3 3 3 5% 72%	2100
	21st to end	Day	4 6% 2 4 3 3 3 3 4 6% 63%	1918
December	1st to 10th	Day	3 4 1 3 2 1 2 2 3 5% 74%	2952
	11th to 20th	Day	4 5% 2 5% 4 3 3 2 4 7% 61%	3499
	21st to end	Day	3 6% 2 4 3 3 4 3 5% 6% 61%	4609
January	1st to 10th	Night	3 8% 3 6% 3 3 4 3 5% 6% 55%	5997
	11th to 20th	Night	3 5% 2 3 2 2 2 2 3 5% 71%	5958
	21st to end	Night	5% 11% 3 6% 4 3 3 3 5% 5% 53%	6468
February	1st to 10th	Night	2 6% 2 5% 3 2 3 2 4 6% 63%	2600
	11th to 20th	Night	4 8% 3 5% 3 3 4 4 4 6% 56%	2500
	21st to end	Night	4 7% 2 4 3 3 3 2 4 5% 61%	1828
March	1st to 10th	Night	3 8% 3 5% 3 3 3 2 4 6% 62%	4940
	11th to 20th	Night	5% 10% 3 6% 3 3 4 3 4 6% 51%	5000
	21st to end	Night	2 6% 2 4 3 3 4 4 5% 7% 62%	5489
April	1st to 10th	Night	3 4 2 5% 3 3 3 3 5% 6% 65%	2080
	11th to 20th	Night	4 4 1 3 2 4 3 2 5% 5% 67%	1977
	21st to end	Night	3 5% 2 4 2 2 3 2 4 6% 67%	2000
May	1st to 10th	Night	5% 5% 2 5% 3 4 3 3 5% 6% 60%	4259
	11th to 20th	Night	2 3 1 4 4 3 3 2 4 6% 67%	4074
	21st to end	Night	2 1 1 3 2 2 3 3 5% 5% 73%	4474
June	1st to 10th	Night	4 3 1 4 3 3 3 3 5% 6% 64%	1800
	11th to 20th	Night	3 2 1 2 2 2 2 2 4 4 76%	1800
	21st to end	Night	3 3 2 5% 4 4 5% 5% 6% 7% 57%	1800
July	1st to 10th	Night	2 3 2 5% 4 4 5% 4 6% 7% 59%	4100
	11th to 20th	Night	3 5% 2 8% 7% 7% 7% 6% 9% 10% 35%	4100
	21st to end	Night	3 5% 2 7% 6% 7% 8% 7% 9% 9% 36%	4472
August	1st to 10th	Night	2 3 2 8% 7% 7% 8% 7% 9% 10% 38%	4033
	11th to 20th	Night	3 4 2 8% 6% 7% 7% 6% 9% 11% 37%	4225
	21st to end	Night	4 4 3 8% 6% 7% 8% 7% 9% 10% 34%	4993
September	1st to 10th	Night	4 5% 2 7% 6% 6% 6% 5% 6% 8% 45%	2000
	11th to 20th	Night	4 2 2 4 3 3 3 4 5% 6% 63%	2139
	21st to end	Night	4 3 1 4 3 3 4 3 5% 5% 65%	2224
October	1st to 10th	Night	3 2 1 3 2 2 3 3 5% 6% 71%	3920
	11th to 20th	Night	5% 3 1 4 3 3 3 2 5% 6% 67%	3898
	21st to end	Night	2 3 1 3 2 2 2 2 4 5% 74%	4252
November	1st to 10th	Night	2 3 1 3 3 3 3 2 5% 6% 71%	2460
	11th to 20th	Night	2 3 1 3 2 2 2 2 4 5% 73%	2520
	21st to end	Night	4 7% 2 3 3 3 3 3 4 5% 63%	2699
December	1st to 10th	Night	4 3 1 2 2 2 2 2 4 6% 70%	4370
	11th to 20th	Night	3 5% 2 4 3 3 3 3 5% 7% 64%	4941
	21st to end	Night	3 6% 2 4 3 3 4 3 5% 6% 62%	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	27% 3 5% 27% 31% 6%	4189
	11th to 20th	Day	18% 3 7% 23% 23% 26%	4154
	21st to end	Day	31% 3 4 14% 23% 24%	4510
February	1st to 10th	Day	27% 2 9% 19% 27% 16%	1800
	11th to 20th	Day	30% 4 5% 22% 25% 14%	1794
	21st to end	Day	29% 3 5% 17% 27% 20%	1799
March	1st to 10th	Day	22% 3 4 14% 35% 21%	4954
	11th to 20th	Day	33% 5% 6% 17% 26% 12%	5000
	21st to end	Day	25% 3 6% 27% 31% 10%	5486
April	1st to 10th	Day	22% 3 5% 17% 33% 19%	2320
	11th to 20th	Day	21% 3 5% 14% 35% 23%	2374
	21st to end	Day	18% 3 6% 17% 38% 19%	2400
May	1st to 10th	Day	22% 2 3 19% 31% 22%	5704
	11th to 20th	Day	17% 4 6% 9% 34% 31%	5844
	21st to end	Day	14% 2 2 7% 28% 48%	6424
June	1st to 10th	Day	14% 4 5% 12% 30% 35%	2600
	11th to 20th	Day	12% 2 3 8% 24% 52%	2600
	21st to end	Day	20% 4 7% 11% 22% 35%	2600
July	1st to 10th	Day	21% 4 5% 9% 14% 47%	5816
	11th to 20th	Day	30% 4 13% 26% 15% 12%	5811
	21st to end	Day	32% 5% 15% 20% 19% 9%	6217
August	1st to 10th	Day	38% 5% 17% 21% 11% 8%	4208
	11th to 20th	Day	29% 5% 11% 23% 18% 13%	4070
	21st to end	Day	33% 5% 15% 19% 21% 7%	4311
September	1st to 10th	Day	30% 5% 9% 17% 22% 17%	2400
	11th to 20th	Day	22% 5% 6% 15% 27% 25%	2256
	21st to end	Day	19% 3 6% 14% 31% 27%	2175
October	1st to 10th	Day	15% 2 4 12% 28% 39%	3270
	11th to 20th	Day	21% 1 2 12% 42% 22%	3250
	21st to end	Day	11% 2 3 16% 38% 30%	3548
November	1st to 10th	Day	15% 2 5% 23% 37% 19%	2059
	11th to 20th	Day	17% 2 6% 20% 38% 18%	2100
	21st to end	Day	24% 2 6% 20% 31% 17%	1918
December	1st to 10th	Day	16% 2 5% 25% 36% 17%	2952
	11th to 20th	Day	25% 3 5% 23% 37% 7%	3498
	21st to end	Day	25% 2 8% 25% 27% 12%	4609
January	1st to 10th	Night	30% 3 5% 25% 31% 7%	5997
	11th to 20th	Night	18% 2 5% 23% 28% 23%	5958
	21st to end	Night	34% 4 5% 13% 23% 21%	6468
February	1st to 10th	Night	23% 3 9% 21% 29% 15%	2600
	11th to 20th	Night	29% 3 6% 23% 23% 15%	2501
	21st to end	Night	24% 4 6% 16% 33% 18%	1828
March	1st to 10th	Night	25% 2 4 18% 34% 17%	4940
	11th to 20th	Night	32% 5% 5% 19% 27% 12%	5000
	21st to end	Night	21% 4 6% 27% 33% 8%	5489
April	1st to 10th	Night	22% 3 4 19% 34% 18%	2080
	11th to 20th	Night	20% 2 4 15% 34% 24%	1977
	21st to end	Night	18% 4 6% 15% 38% 19%	2000
May	1st to 10th	Night	24% 2 6% 18% 34% 15%	4256
	11th to 20th	Night	18% 4 6% 10% 36% 27%	4075
	21st to end	Night	14% 2 3 8% 29% 44%	4474
June	1st to 10th	Night	19% 4 5% 10% 28% 34%	1800
	11th to 20th	Night	13% 3 3 8% 21% 52%	1800
	21st to end	Night	25% 4 7% 14% 17% 33%	1800
July	1st to 10th	Night	24% 4 9% 10% 13% 40%	4055
	11th to 20th	Night	39% 5% 15% 21% 6% 13%	4046
	21st to end	Night	41% 6% 18% 16% 14% 5%	4344
August	1st to 10th	Night	43% 6% 21% 12% 9% 7%	2928
	11th to 20th	Night	39% 6% 17% 14% 11% 13%	3054
	21st to end	Night	36% 6% 17% 20% 13% 7%	3597
September	1st to 10th	Night	34% 7% 11% 18% 15% 16%	2000
	11th to 20th	Night	21% 6% 9% 16% 25% 23%	2139
	21st to end	Night	20% 4 6% 14% 27% 29%	2224
October	1st to 10th	Night	15% 3 5% 12% 27% 38%	3920
	11th to 20th	Night	20% 1 3 16% 36% 24%	3898
	21st to end	Night	15% 2 2 14% 39% 28%	4252
November	1st to 10th	Night	16% 2 4 21% 37% 20%	2460
	11th to 20th	Night	15% 3 5% 19% 37% 21%	2520
	21st to end	Night	24% 2 6% 18% 31% 18%	2699
December	1st to 10th	Night	17% 2 4 28% 29% 20%	4370
	11th to 20th	Night	21% 3 6% 19% 38% 14%	4941
	21st to end	Night	23% 3 6% 26% 31% 12%	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% 29% 32% 16% 2	330
	11th to 20th	Day	11% 9% 25% 30% 21% 4	318
	21st to end	Day	5% 12% 26% 31% 19% 8%	330
February	1st to 10th	Day	4 12% 30% 35% 14% 5%	300
	11th to 20th	Day	11% 14% 29% 35% 11% 1	300
	21st to end	Day	12% 20% 34% 23% 8% 3	398
March	1st to 10th	Day	12% 20% 29% 24% 13% 2	500
	11th to 20th	Day	13% 18% 30% 22% 14% 3	500
	21st to end	Day	11% 25% 31% 22% 8% 3	550
April	1st to 10th	Day	7% 15% 31% 27% 14% 5%	500
	11th to 20th	Day	11% 19% 32% 23% 12% 3	492
	21st to end	Day	7% 18% 32% 24% 15% 4	500
May	1st to 10th	Day	7% 14% 32% 32% 14% 2	503
	11th to 20th	Day	7% 13% 28% 29% 17% 6%	528
	21st to end	Day	5% 15% 29% 27% 18% 6%	573
June	1st to 10th	Day	4 7% 24% 33% 24% 9%	530
	11th to 20th	Day	3 9% 25% 30% 22% 12%	530
	21st to end	Day	4 5% 21% 36% 24% 10%	530
July	1st to 10th	Day	4 2 12% 32% 35% 16%	526
	11th to 20th	Day	6% 1 5% 24% 35% 28%	524
	21st to end	Day	5% 2 5% 25% 38% 24%	575
August	1st to 10th	Day	7% 2 7% 24% 38% 21%	527
	11th to 20th	Day	7% 4 11% 26% 29% 23%	517
	21st to end	Day	8% 1 8% 28% 30% 26%	583
September	1st to 10th	Day	5% 3 12% 27% 34% 19%	530
	11th to 20th	Day	3 4 20% 32% 32% 9%	530
	21st to end	Day	6% 6% 18% 29% 29% 12%	505
October	1st to 10th	Day	5% 7% 22% 24% 25% 17%	330
	11th to 20th	Day	7% 11% 19% 30% 21% 12%	330
	21st to end	Day	6% 8% 18% 26% 31% 11%	363
November	1st to 10th	Day	5% 8% 25% 33% 22% 7%	330
	11th to 20th	Day	6% 6% 18% 31% 27% 12%	330
	21st to end	Day	7% 12% 23% 28% 24% 6%	330
December	1st to 10th	Day	9% 6% 21% 29% 28% 6%	330
	11th to 20th	Day	6% 8% 25% 31% 22% 8%	330
	21st to end	Day	15% 11% 25% 30% 15% 4	363
January	1st to 10th	Night	8% 3 23% 43% 21% 3	840
	11th to 20th	Night	7% 4 24% 42% 19% 3	824
	21st to end	Night	9% 5% 22% 42% 19% 3	880
February	1st to 10th	Night	5% 6% 27% 41% 18% 2	800
	11th to 20th	Night	10% 5% 29% 42% 13% 1	784
	21st to end	Night	9% 7% 31% 42% 10%	660
March	1st to 10th	Night	7% 8% 31% 41% 13% 1	800
	11th to 20th	Night	8% 9% 24% 40% 18% 1	800
	21st to end	Night	6% 8% 29% 41% 14% 1	880
April	1st to 10th	Night	5% 9% 31% 40% 14% 1	680
	11th to 20th	Night	7% 9% 33% 37% 13% 1	593
	21st to end	Night	4 8% 35% 38% 13% 1	600
May	1st to 10th	Night	4 5% 31% 45% 13% 1	600
	11th to 20th	Night	4 6% 26% 42% 21% 1	591
	21st to end	Night	4 5% 26% 45% 19% 1	650
June	1st to 10th	Night	5% 4 19% 50% 22% 1	600
	11th to 20th	Night	3 3 22% 49% 23% 1	600
	21st to end	Night	5% 2 15% 45% 32% 2	600
July	1st to 10th	Night	5% 1 7% 41% 42% 3	585
	11th to 20th	Night	7% 2 4 29% 52% 7%	582
	21st to end	Night	8% 2 3 28% 50% 10%	657
August	1st to 10th	Night	5% 2 4 26% 53% 11%	597
	11th to 20th	Night	7% 2 5% 31% 47% 7%	594
	21st to end	Night	6% 1 3 30% 52% 7%	660
September	1st to 10th	Night	5% 3 8% 43% 39% 3	600
	11th to 20th	Night	4 1 10% 43% 37% 4	739
	21st to end	Night	5% 3 14% 40% 34% 5%	800
October	1st to 10th	Night	6% 3 18% 44% 27% 3	800
	11th to 20th	Night	4 4 18% 46% 25% 4	800
	21st to end	Night	4 2 19% 42% 27% 5%	880
November	1st to 10th	Night	4 3 18% 45% 27% 4	820
	11th to 20th	Night	5% 2 20% 43% 26% 5%	840
	21st to end	Night	9% 6% 19% 37% 25% 3	840
December	1st to 10th	Night	9% 4 18% 45% 22% 3	840
	11th to 20th	Night	9% 4 22% 43% 20% 1	840
	21st to end	Night	9% 5% 24% 44% 15% 2	924

Page generated at 2026-01-13 23:14:30. Version ac07

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