Infinity's Edge Observatory - CO
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Infinity's Edge Observatory - CO clear sky chart from 2005-11-06 to 2026-02-01.

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 5% 4 4 5% 4 7% 9% 53%	136208
	Night	2 5% 2 5% 3 3 4 4 6% 8% 59%	133285
Transparency	Day	25% 7% 11% 24% 24% 10%	131165
	Night	22% 6% 12% 26% 25% 8%	129332
Seeing	Day	9% 14% 29% 29% 15% 4	17142
	Night	5% 8% 32% 41% 13% 1	27299

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	5% 3 6% 3 3 3 3 4 7% 62%	3718
	11th to 20th	Day	2 1 7% 4 5% 4 3 5% 9% 60%	4002
	21st to end	Day	4 2 6% 4 3 3 3 5% 8% 62%	4609
February	1st to 10th	Day	4 2 6% 4 3 4 4 5% 8% 60%	1800
	11th to 20th	Day	2 1 4 3 3 3 4 6% 8% 65%	1915
	21st to end	Day	4 2 6% 3 4 4 3 5% 7% 63%	1650
March	1st to 10th	Day	1 5% 2 5% 3 3 3 3 5% 7% 64%	4536
	11th to 20th	Day	2 8% 3 8% 7% 5% 5% 4 6% 8% 44%	5000
	21st to end	Day	1 4 2 4 4 4 4 4 7% 10% 56%	5766
April	1st to 10th	Day	2 6% 2 5% 4 4 5% 5% 6% 9% 53%	2400
	11th to 20th	Day	4 8% 3 7% 4 4 5% 4 6% 8% 48%	2371
	21st to end	Day	3 9% 3 7% 5% 4 5% 4 6% 9% 45%	2400
May	1st to 10th	Day	5% 9% 3 6% 4 4 5% 4 7% 10% 45%	5596
	11th to 20th	Day	3 6% 2 6% 5% 5% 6% 5% 7% 9% 45%	6289
	21st to end	Day	2 4 2 5% 4 5% 5% 4 8% 11% 50%	6925
June	1st to 10th	Day	3 4 2 6% 4 5% 6% 5% 8% 11% 47%	2800
	11th to 20th	Day	4 4 2 5% 3 4 5% 4 6% 8% 54%	2800
	21st to end	Day	3 4 2 5% 5% 5% 6% 6% 8% 9% 48%	2800
July	1st to 10th	Day	3 3 1 4 4 5% 6% 5% 7% 9% 53%	6339
	11th to 20th	Day	4 4 2 7% 5% 5% 7% 6% 9% 11% 41%	6340
	21st to end	Day	6% 5% 3 7% 5% 5% 7% 5% 8% 9% 40%	6587
August	1st to 10th	Day	5% 4 2 7% 6% 6% 7% 5% 9% 12% 38%	5779
	11th to 20th	Day	3 3 1 5% 4 5% 6% 6% 8% 10% 49%	5371
	21st to end	Day	4 4 2 7% 5% 6% 7% 5% 8% 10% 41%	5984
September	1st to 10th	Day	6% 4 2 6% 4 5% 5% 4 6% 8% 50%	2400
	11th to 20th	Day	5% 4 2 5% 4 4 5% 3 6% 6% 56%	2397
	21st to end	Day	4 4 1 5% 3 3 3 3 5% 6% 62%	2185
October	1st to 10th	Day	2 3 1 3 3 2 3 2 4 5% 72%	3270
	11th to 20th	Day	2 4 2 4 3 4 4 4 5% 9% 58%	3250
	21st to end	Day	2 3 1 3 3 2 3 2 4 6% 71%	3499
November	1st to 10th	Day	1 4 2 3 3 2 2 3 6% 6% 70%	1853
	11th to 20th	Day	3 1 3 3 2 2 3 5% 7% 69%	1890
	21st to end	Day	4 2 5% 3 3 3 3 5% 9% 63%	1789
December	1st to 10th	Day	3 2 4 2 2 2 2 4 6% 72%	2700
	11th to 20th	Day	2 1 4 2 2 3 3 5% 9% 68%	3106
	21st to end	Day	3 1 5% 3 3 4 4 7% 10% 59%	4092
January	1st to 10th	Night	3 3 8% 3 3 4 3 5% 8% 58%	6467
	11th to 20th	Night	1 2 1 4 3 4 3 3 5% 6% 67%	6230
	21st to end	Night	4 3 5% 3 4 4 3 5% 7% 62%	6611
February	1st to 10th	Night	3 3 5% 4 2 3 3 4 8% 65%	2600
	11th to 20th	Night	1 4 2 6% 3 3 3 3 4 7% 62%	2369
	21st to end	Night	4 2 6% 3 3 3 3 5% 7% 64%	1980
March	1st to 10th	Night	1 6% 3 5% 3 3 3 3 5% 7% 61%	5335
	11th to 20th	Night	1 9% 3 7% 3 3 4 4 5% 6% 55%	5000
	21st to end	Night	1 6% 2 5% 4 3 4 3 6% 9% 58%	5196
April	1st to 10th	Night	1 5% 1 5% 4 3 3 3 5% 7% 62%	2000
	11th to 20th	Night	3 10% 3 7% 3 3 4 3 5% 7% 52%	1977
	21st to end	Night	3 10% 2 7% 4 3 3 3 6% 7% 52%	2000
May	1st to 10th	Night	5% 11% 3 7% 4 4 4 3 5% 8% 46%	4384
	11th to 20th	Night	4 7% 2 5% 3 3 4 3 6% 8% 52%	3622
	21st to end	Night	4 8% 2 5% 3 3 4 3 6% 8% 54%	3972
June	1st to 10th	Night	3 3 2 4 4 3 4 4 8% 8% 57%	1600
	11th to 20th	Night	3 2 1 3 3 3 3 4 6% 8% 63%	1600
	21st to end	Night	3 4 1 5% 4 4 4 5% 8% 9% 54%	1600
July	1st to 10th	Night	3 3 1 5% 4 5% 5% 5% 7% 9% 54%	3640
	11th to 20th	Night	2 3 2 5% 4 5% 5% 6% 9% 14% 47%	3640
	21st to end	Night	3 4 2 6% 4 5% 6% 6% 9% 11% 44%	4281
August	1st to 10th	Night	4 5% 2 6% 5% 4 5% 4 8% 11% 46%	4033
	11th to 20th	Night	2 3 1 4 4 5% 6% 5% 8% 11% 50%	4475
	21st to end	Night	5% 6% 2 7% 6% 6% 6% 6% 8% 10% 37%	4993
September	1st to 10th	Night	5% 4 2 5% 4 5% 5% 5% 7% 8% 50%	2000
	11th to 20th	Night	5% 4 2 4 3 3 4 3 6% 9% 57%	2001
	21st to end	Night	5% 5% 2 5% 4 3 3 3 5% 6% 60%	2210
October	1st to 10th	Night	3 3 1 4 3 3 3 2 4 5% 69%	3920
	11th to 20th	Night	2 6% 1 4 3 3 3 3 4 7% 64%	3898
	21st to end	Night	1 3 1 3 2 2 2 2 4 6% 73%	4268
November	1st to 10th	Night	1 3 1 3 3 3 3 2 4 6% 70%	2665
	11th to 20th	Night	3 1 3 2 2 2 3 5% 7% 71%	2730
	21st to end	Night	1 5% 2 3 3 3 3 3 5% 7% 65%	2829
December	1st to 10th	Night	2 1 4 2 1 2 2 4 7% 75%	4710
	11th to 20th	Night	2 1 2 2 2 3 3 5% 7% 71%	5321
	21st to end	Night	1 4 2 6% 4 4 4 3 5% 8% 58%	7128

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	20% 5% 12% 31% 24% 8%	3719
	11th to 20th	Day	19% 6% 13% 22% 30% 10%	4002
	21st to end	Day	20% 5% 9% 27% 26% 12%	4609
February	1st to 10th	Day	21% 5% 16% 27% 20% 10%	1800
	11th to 20th	Day	16% 5% 11% 29% 31% 7%	1925
	21st to end	Day	21% 4 9% 24% 28% 14%	1650
March	1st to 10th	Day	19% 4 7% 18% 34% 19%	4536
	11th to 20th	Day	34% 7% 9% 24% 22% 5%	5000
	21st to end	Day	21% 6% 11% 43% 17% 2	5766
April	1st to 10th	Day	25% 7% 13% 25% 21% 10%	2400
	11th to 20th	Day	31% 8% 10% 24% 21% 7%	2374
	21st to end	Day	32% 9% 10% 27% 19% 3	2400
May	1st to 10th	Day	32% 8% 10% 24% 20% 6%	5596
	11th to 20th	Day	29% 9% 11% 21% 22% 8%	6293
	21st to end	Day	24% 9% 12% 22% 27% 7%	6926
June	1st to 10th	Day	28% 9% 15% 20% 20% 8%	2800
	11th to 20th	Day	25% 8% 9% 18% 23% 18%	2800
	21st to end	Day	27% 8% 11% 21% 20% 12%	2800
July	1st to 10th	Day	21% 7% 9% 16% 21% 26%	6271
	11th to 20th	Day	31% 8% 15% 24% 14% 6%	6265
	21st to end	Day	36% 8% 15% 15% 15% 11%	6398
August	1st to 10th	Day	39% 9% 18% 17% 12% 4	4208
	11th to 20th	Day	30% 9% 14% 15% 20% 12%	3887
	21st to end	Day	31% 8% 14% 17% 23% 7%	4311
September	1st to 10th	Day	29% 6% 10% 19% 24% 11%	2400
	11th to 20th	Day	26% 6% 10% 19% 28% 12%	2397
	21st to end	Day	23% 4 7% 23% 34% 9%	2185
October	1st to 10th	Day	15% 4 6% 17% 37% 21%	3270
	11th to 20th	Day	22% 4 8% 30% 28% 8%	3250
	21st to end	Day	15% 3 6% 24% 43% 9%	3499
November	1st to 10th	Day	15% 4 9% 24% 35% 13%	1853
	11th to 20th	Day	14% 5% 6% 36% 30% 9%	1890
	21st to end	Day	19% 4 10% 27% 29% 10%	1789
December	1st to 10th	Day	15% 4 10% 33% 29% 9%	2700
	11th to 20th	Day	14% 5% 11% 35% 30% 6%	3104
	21st to end	Day	17% 6% 11% 28% 29% 9%	4092
January	1st to 10th	Night	22% 5% 10% 30% 27% 6%	6467
	11th to 20th	Night	15% 5% 11% 27% 27% 15%	6230
	21st to end	Night	19% 7% 11% 25% 28% 10%	6611
February	1st to 10th	Night	19% 4 14% 32% 23% 8%	2600
	11th to 20th	Night	22% 5% 11% 30% 25% 7%	2369
	21st to end	Night	19% 4 7% 28% 29% 12%	1980
March	1st to 10th	Night	22% 3 8% 18% 38% 10%	5335
	11th to 20th	Night	27% 7% 8% 21% 29% 8%	5000
	21st to end	Night	21% 7% 16% 38% 16% 1	5196
April	1st to 10th	Night	21% 5% 13% 31% 25% 6%	2000
	11th to 20th	Night	31% 6% 10% 28% 21% 5%	1977
	21st to end	Night	31% 6% 14% 27% 19% 3	2000
May	1st to 10th	Night	35% 7% 14% 24% 13% 6%	4381
	11th to 20th	Night	26% 9% 11% 28% 21% 5%	3623
	21st to end	Night	26% 8% 15% 21% 26% 5%	3972
June	1st to 10th	Night	22% 10% 21% 24% 14% 10%	1600
	11th to 20th	Night	16% 8% 14% 22% 23% 18%	1600
	21st to end	Night	24% 8% 13% 23% 21% 11%	1600
July	1st to 10th	Night	24% 8% 10% 20% 26% 12%	3600
	11th to 20th	Night	23% 9% 25% 28% 12% 4	3592
	21st to end	Night	28% 10% 22% 20% 10% 10%	4158
August	1st to 10th	Night	37% 11% 21% 17% 10% 4	2928
	11th to 20th	Night	26% 9% 23% 18% 17% 6%	3235
	21st to end	Night	28% 10% 21% 20% 19% 2	3597
September	1st to 10th	Night	28% 7% 13% 23% 20% 8%	2000
	11th to 20th	Night	23% 7% 12% 23% 23% 12%	2001
	21st to end	Night	24% 4 10% 26% 29% 7%	2210
October	1st to 10th	Night	17% 6% 8% 24% 33% 13%	3920
	11th to 20th	Night	20% 4 11% 32% 25% 8%	3898
	21st to end	Night	13% 3 6% 29% 38% 10%	4268
November	1st to 10th	Night	15% 5% 10% 26% 33% 11%	2665
	11th to 20th	Night	13% 5% 8% 35% 30% 9%	2730
	21st to end	Night	19% 4 10% 29% 29% 10%	2829
December	1st to 10th	Night	12% 3 11% 37% 30% 7%	4710
	11th to 20th	Night	12% 5% 10% 33% 36% 5%	5322
	21st to end	Night	22% 7% 11% 23% 32% 6%	7128

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	7% 19% 30% 32% 12%	330
	11th to 20th	Day	10% 16% 38% 31% 5% 1	330
	21st to end	Day	3 16% 39% 30% 9% 2	363
February	1st to 10th	Day	6% 30% 37% 22% 4 1	300
	11th to 20th	Day	6% 26% 38% 25% 4 1	300
	21st to end	Day	9% 25% 40% 20% 5% 1	249
March	1st to 10th	Day	7% 22% 33% 28% 10%	310
	11th to 20th	Day	10% 23% 36% 21% 10% 1	500
	21st to end	Day	12% 28% 37% 19% 5%	550
April	1st to 10th	Day	12% 23% 37% 21% 6% 1	500
	11th to 20th	Day	18% 27% 33% 17% 4 1	492
	21st to end	Day	12% 24% 38% 18% 6% 2	500
May	1st to 10th	Day	14% 20% 35% 21% 8% 2	568
	11th to 20th	Day	10% 15% 27% 32% 14% 3	725
	21st to end	Day	9% 16% 26% 29% 18% 2	789
June	1st to 10th	Day	5% 12% 25% 31% 22% 5%	730
	11th to 20th	Day	8% 11% 27% 34% 16% 4	730
	21st to end	Day	5% 8% 28% 33% 21% 5%	730
July	1st to 10th	Day	7% 5% 17% 35% 29% 8%	721
	11th to 20th	Day	9% 2 14% 35% 31% 9%	718
	21st to end	Day	12% 5% 14% 30% 31% 8%	657
August	1st to 10th	Day	11% 5% 24% 32% 21% 7%	527
	11th to 20th	Day	7% 5% 22% 36% 21% 9%	517
	21st to end	Day	10% 5% 26% 32% 20% 7%	583
September	1st to 10th	Day	9% 6% 23% 32% 24% 6%	530
	11th to 20th	Day	6% 10% 31% 34% 15% 3	527
	21st to end	Day	6% 10% 20% 32% 22% 10%	330
October	1st to 10th	Day	6% 14% 24% 27% 20% 10%	330
	11th to 20th	Day	7% 20% 25% 27% 19% 3	330
	21st to end	Day	11% 13% 33% 29% 12% 3	363
November	1st to 10th	Day	9% 15% 33% 30% 9% 4	330
	11th to 20th	Day	5% 17% 32% 34% 10% 2	330
	21st to end	Day	4 14% 40% 30% 10% 1	330
December	1st to 10th	Day	7% 16% 38% 28% 8% 2	330
	11th to 20th	Day	8% 17% 39% 29% 7% 1	330
	21st to end	Day	10% 19% 40% 22% 7% 2	363
January	1st to 10th	Night	2 12% 41% 36% 8% 1	1050
	11th to 20th	Night	2 14% 43% 33% 7% 1	943
	21st to end	Night	1 8% 42% 41% 7% 1	924
February	1st to 10th	Night	1 9% 48% 36% 6%	800
	11th to 20th	Night	2 10% 48% 35% 5%	784
	21st to end	Night	2 9% 52% 34% 3	660
March	1st to 10th	Night	3 12% 42% 37% 6%	800
	11th to 20th	Night	5% 7% 37% 43% 8%	800
	21st to end	Night	4 11% 43% 38% 4	755
April	1st to 10th	Night	6% 13% 39% 39% 4	600
	11th to 20th	Night	11% 11% 37% 34% 6% 1	593
	21st to end	Night	9% 10% 35% 38% 8%	600
May	1st to 10th	Night	11% 9% 32% 39% 10% 1	600
	11th to 20th	Night	9% 5% 25% 47% 13% 2	591
	21st to end	Night	9% 9% 26% 39% 16% 2	650
June	1st to 10th	Night	5% 5% 20% 48% 20% 3	600
	11th to 20th	Night	5% 3 26% 50% 14% 2	600
	21st to end	Night	4 3 17% 48% 27% 2	600
July	1st to 10th	Night	7% 3 9% 42% 36% 3	585
	11th to 20th	Night	5% 2 9% 42% 39% 4	582
	21st to end	Night	8% 2 5% 37% 44% 4	657
August	1st to 10th	Night	8% 3 8% 44% 34% 3	597
	11th to 20th	Night	6% 3 9% 49% 31% 3	594
	21st to end	Night	7% 2 10% 46% 33% 2	660
September	1st to 10th	Night	7% 2 13% 48% 26% 5%	600
	11th to 20th	Night	8% 2 17% 49% 23% 2	600
	21st to end	Night	6% 4 25% 44% 19% 2	610
October	1st to 10th	Night	5% 7% 26% 45% 15% 2	800
	11th to 20th	Night	3 6% 32% 46% 12% 1	800
	21st to end	Night	5% 6% 34% 41% 12% 2	884
November	1st to 10th	Night	3 8% 37% 41% 10% 1	1025
	11th to 20th	Night	2 12% 38% 40% 7% 1	1050
	21st to end	Night	4 10% 35% 43% 7%	1050
December	1st to 10th	Night	2 11% 42% 38% 6%	1050
	11th to 20th	Night	4 12% 43% 36% 6%	1050
	21st to end	Night	3 15% 43% 34% 5%	1155

Page generated at 2026-01-28 23:21:42. Version ac07

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