Caney Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caney Observatory clear sky chart from 2005-11-06 to 2026-07-31.

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	12% 7% 2 6% 4 4 4 3 5% 7% 45%	137745
	Night	12% 7% 2 6% 4 3 4 3 5% 6% 47%	135512
Transparency	Day	37% 6% 11% 25% 18% 4	141354
	Night	36% 5% 11% 25% 19% 4	139983
Seeing	Day	17% 11% 26% 25% 16% 4	17890
	Night	16% 10% 28% 30% 14% 1	27644

By Month

Percentage Cloud Cover SE (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	15% 10% 2 5% 4 3 4 3 3 4 46%	5289
	11th to 20th	Day	8% 8% 3 7% 4 4 3 3 4 6% 51%	5310
	21st to end	Day	17% 9% 3 6% 3 3 3 2 3 4 47%	5812
February	1st to 10th	Day	16% 9% 3 7% 4 4 4 3 4 5% 39%	1890
	11th to 20th	Day	16% 9% 2 6% 4 3 3 2 3 6% 44%	1911
	21st to end	Day	16% 10% 3 6% 5% 3 4 3 5% 6% 41%	1777
March	1st to 10th	Day	14% 11% 2 5% 3 3 3 3 4 6% 46%	5046
	11th to 20th	Day	10% 5% 2 5% 3 3 4 3 5% 7% 53%	5090
	21st to end	Day	13% 7% 3 8% 5% 5% 5% 4 6% 7% 36%	5583
April	1st to 10th	Day	15% 7% 2 5% 4 4 4 3 6% 6% 44%	2509
	11th to 20th	Day	17% 8% 3 6% 4 4 4 3 5% 5% 40%	2494
	21st to end	Day	20% 9% 3 7% 5% 4 4 3 5% 5% 36%	2520
May	1st to 10th	Day	15% 7% 2 7% 5% 5% 5% 4 6% 7% 38%	7317
	11th to 20th	Day	12% 7% 3 8% 5% 4 5% 3 5% 7% 39%	7627
	21st to end	Day	22% 8% 3 7% 5% 4 5% 3 6% 8% 31%	8768
June	1st to 10th	Day	9% 6% 2 5% 5% 4 6% 4 7% 9% 43%	2940
	11th to 20th	Day	6% 5% 2 5% 5% 5% 5% 4 7% 10% 45%	2940
	21st to end	Day	5% 4 1 4 4 5% 5% 4 8% 9% 50%	2940
July	1st to 10th	Day	8% 5% 2 5% 4 5% 5% 5% 6% 10% 44%	6107
	11th to 20th	Day	6% 4 2 6% 5% 5% 6% 4 7% 11% 45%	6030
	21st to end	Day	6% 5% 2 5% 4 4 5% 5% 7% 11% 45%	6553
August	1st to 10th	Day	5% 3 1 4 4 3 5% 4 6% 8% 58%	4234
	11th to 20th	Day	11% 4 2 6% 5% 4 4 4 6% 8% 45%	3990
	21st to end	Day	6% 3 1 5% 4 4 4 4 6% 8% 55%	4312
September	1st to 10th	Day	11% 5% 2 5% 4 4 4 4 6% 6% 49%	2400
	11th to 20th	Day	10% 7% 2 6% 5% 4 5% 3 5% 7% 46%	2375
	21st to end	Day	8% 5% 2 5% 4 3 4 3 6% 6% 54%	2096
October	1st to 10th	Day	10% 3 1 5% 4 4 3 3 4 6% 58%	2000
	11th to 20th	Day	14% 5% 2 5% 3 3 3 3 3 5% 56%	2000
	21st to end	Day	19% 7% 2 5% 3 3 3 2 4 5% 48%	2200
November	1st to 10th	Day	14% 6% 2 4 2 3 3 2 3 5% 57%	2058
	11th to 20th	Day	14% 6% 2 5% 2 3 3 3 4 6% 51%	1945
	21st to end	Day	20% 7% 3 5% 4 3 2 3 4 4 46%	1711
December	1st to 10th	Day	11% 10% 2 5% 3 3 3 2 3 4 54%	2690
	11th to 20th	Day	14% 10% 3 6% 4 3 3 3 3 5% 46%	3088
	21st to end	Day	18% 20% 4 7% 4 3 3 2 4 5% 30%	4193
January	1st to 10th	Night	13% 9% 4 7% 4 4 3 3 4 5% 44%	7634
	11th to 20th	Night	9% 6% 2 8% 4 3 4 3 4 5% 53%	7680
	21st to end	Night	17% 9% 3 6% 4 4 3 3 4 5% 43%	8402
February	1st to 10th	Night	16% 9% 2 6% 4 3 3 3 5% 6% 43%	2730
	11th to 20th	Night	16% 7% 3 7% 4 3 3 3 4 6% 44%	2595
	21st to end	Night	16% 7% 3 4 3 3 3 3 4 6% 46%	2045
March	1st to 10th	Night	17% 11% 3 6% 4 4 3 2 3 4 44%	5029
	11th to 20th	Night	9% 9% 2 6% 3 3 3 3 4 5% 52%	5090
	21st to end	Night	13% 7% 3 6% 4 4 5% 4 5% 7% 42%	5588
April	1st to 10th	Night	12% 6% 2 5% 3 3 3 3 5% 7% 51%	2109
	11th to 20th	Night	15% 6% 2 5% 3 3 5% 4 5% 7% 47%	2075
	21st to end	Night	18% 7% 2 7% 3 3 4 3 6% 7% 40%	2100
May	1st to 10th	Night	15% 7% 2 6% 4 3 4 3 5% 7% 44%	5535
	11th to 20th	Night	13% 6% 2 6% 4 4 4 4 7% 9% 40%	5265
	21st to end	Night	22% 10% 4 7% 4 4 4 3 5% 7% 30%	5399
June	1st to 10th	Night	8% 4 2 5% 4 3 4 4 6% 9% 52%	1680
	11th to 20th	Night	5% 3 1 3 4 4 4 4 7% 10% 55%	1680
	21st to end	Night	3 3 1 4 4 3 4 3 5% 9% 61%	1680
July	1st to 10th	Night	7% 5% 2 6% 5% 4 5% 5% 7% 9% 45%	4071
	11th to 20th	Night	4 3 2 5% 4 4 4 4 6% 9% 56%	4167
	21st to end	Night	4 5% 2 5% 4 4 4 4 6% 11% 50%	4539
August	1st to 10th	Night	3 2 1 3 3 3 4 4 6% 9% 62%	2926
	11th to 20th	Night	9% 4 2 5% 4 4 4 3 6% 8% 51%	3060
	21st to end	Night	5% 3 1 4 3 3 4 3 5% 8% 62%	3586
September	1st to 10th	Night	9% 4 1 5% 4 3 4 3 5% 8% 55%	2000
	11th to 20th	Night	9% 5% 2 5% 4 4 4 3 6% 8% 50%	2020
	21st to end	Night	8% 4 2 5% 3 4 3 3 4 7% 57%	2283
October	1st to 10th	Night	6% 4 1 3 4 3 3 3 5% 7% 60%	2400
	11th to 20th	Night	13% 4 1 4 3 3 3 3 4 5% 56%	2400
	21st to end	Night	18% 6% 2 5% 3 2 2 2 3 5% 50%	2640
November	1st to 10th	Night	12% 6% 2 4 3 2 2 2 3 6% 57%	2460
	11th to 20th	Night	12% 6% 2 4 3 2 3 3 5% 5% 55%	2672
	21st to end	Night	17% 8% 3 4 3 3 3 3 4 6% 46%	2904
December	1st to 10th	Night	12% 9% 2 5% 3 3 3 3 4 6% 50%	4720
	11th to 20th	Night	16% 8% 3 6% 4 3 3 2 3 4 48%	5339
	21st to end	Night	23% 17% 3 7% 4 3 3 3 4 4 30%	7009

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	43% 3 8% 27% 17% 2	5290
	11th to 20th	Day	34% 3 7% 30% 20% 5%	5310
	21st to end	Day	42% 3 7% 20% 20% 7%	5812
February	1st to 10th	Day	47% 5% 11% 23% 12% 2	1890
	11th to 20th	Day	43% 4 11% 21% 17% 4	1920
	21st to end	Day	45% 5% 6% 21% 16% 7%	1777
March	1st to 10th	Day	40% 4 7% 21% 14% 13%	5046
	11th to 20th	Day	30% 5% 7% 23% 23% 12%	5090
	21st to end	Day	44% 7% 11% 26% 11% 1	5585
April	1st to 10th	Day	39% 7% 11% 22% 19% 2	2509
	11th to 20th	Day	44% 6% 12% 19% 16% 4	2494
	21st to end	Day	50% 6% 10% 21% 13% 1	2520
May	1st to 10th	Day	43% 8% 10% 22% 15% 2	7352
	11th to 20th	Day	43% 7% 11% 21% 16% 2	7631
	21st to end	Day	50% 8% 11% 17% 13% 1	8782
June	1st to 10th	Day	35% 9% 14% 25% 15% 1	2940
	11th to 20th	Day	32% 8% 14% 30% 14% 2	2940
	21st to end	Day	27% 9% 16% 28% 16% 4	2940
July	1st to 10th	Day	33% 8% 15% 25% 17% 2	6043
	11th to 20th	Day	30% 9% 17% 29% 14% 1	5961
	21st to end	Day	30% 8% 19% 30% 12%	6371
August	1st to 10th	Day	22% 7% 18% 29% 21% 2	4220
	11th to 20th	Day	36% 6% 15% 29% 13% 1	4029
	21st to end	Day	26% 7% 13% 36% 15% 3	4311
September	1st to 10th	Day	33% 7% 11% 25% 16% 8%	2400
	11th to 20th	Day	37% 6% 10% 23% 22% 2	2375
	21st to end	Day	29% 5% 9% 27% 26% 3	2096
October	1st to 10th	Day	17% 4 6% 17% 43% 14%	3260
	11th to 20th	Day	21% 2 6% 21% 37% 12%	3240
	21st to end	Day	31% 3 8% 31% 23% 4	3538
November	1st to 10th	Day	32% 4 9% 28% 22% 6%	2058
	11th to 20th	Day	34% 4 8% 24% 23% 7%	1945
	21st to end	Day	42% 4 9% 21% 22% 2	1711
December	1st to 10th	Day	35% 3 9% 33% 19% 1	2690
	11th to 20th	Day	41% 5% 6% 25% 22% 1	3085
	21st to end	Day	56% 6% 8% 19% 10% 1	4193
January	1st to 10th	Night	42% 4 10% 29% 13% 2	7635
	11th to 20th	Night	32% 4 8% 22% 30% 4	7680
	21st to end	Night	44% 4 8% 20% 21% 3	8402
February	1st to 10th	Night	41% 5% 12% 25% 15% 3	2730
	11th to 20th	Night	43% 4 10% 22% 19% 3	2596
	21st to end	Night	39% 4 10% 20% 20% 8%	2045
March	1st to 10th	Night	45% 4 7% 17% 18% 9%	5029
	11th to 20th	Night	34% 4 8% 24% 19% 11%	5090
	21st to end	Night	39% 6% 11% 27% 15% 1	5588
April	1st to 10th	Night	32% 5% 13% 24% 21% 5%	2109
	11th to 20th	Night	36% 6% 10% 23% 19% 6%	2075
	21st to end	Night	43% 6% 11% 24% 15% 2	2100
May	1st to 10th	Night	39% 6% 13% 25% 15% 2	5565
	11th to 20th	Night	38% 9% 11% 23% 14% 4	5266
	21st to end	Night	53% 8% 10% 18% 9% 2	5410
June	1st to 10th	Night	27% 8% 14% 30% 18% 3	1680
	11th to 20th	Night	22% 7% 15% 33% 19% 3	1680
	21st to end	Night	21% 7% 16% 31% 19% 6%	1680
July	1st to 10th	Night	32% 9% 16% 22% 19% 3	4028
	11th to 20th	Night	23% 8% 16% 35% 16% 1	4116
	21st to end	Night	26% 7% 18% 33% 14%	4410
August	1st to 10th	Night	17% 7% 18% 35% 22% 1	2916
	11th to 20th	Night	30% 7% 18% 29% 14% 2	3087
	21st to end	Night	20% 6% 13% 38% 19% 4	3586
September	1st to 10th	Night	27% 6% 12% 29% 19% 8%	2000
	11th to 20th	Night	32% 6% 11% 23% 23% 5%	2020
	21st to end	Night	28% 5% 10% 21% 33% 4	2283
October	1st to 10th	Night	14% 3 8% 15% 42% 18%	3920
	11th to 20th	Night	21% 3 6% 19% 32% 19%	3899
	21st to end	Night	31% 3 6% 28% 26% 6%	4252
November	1st to 10th	Night	31% 4 8% 25% 24% 7%	2460
	11th to 20th	Night	30% 4 8% 26% 25% 7%	2672
	21st to end	Night	40% 5% 8% 24% 21% 3	2904
December	1st to 10th	Night	36% 4 9% 33% 16% 1	4720
	11th to 20th	Night	42% 3 7% 24% 21% 4	5341
	21st to end	Night	56% 5% 9% 20% 7% 2	7009

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	24% 23% 35% 15% 2	330
	11th to 20th	Day	29% 22% 37% 9% 2	330
	21st to end	Day	25% 27% 31% 15% 2	363
February	1st to 10th	Day	25% 21% 39% 12% 4	330
	11th to 20th	Day	32% 24% 32% 9% 3	330
	21st to end	Day	34% 20% 37% 8% 2	273
March	1st to 10th	Day	27% 22% 36% 14% 2	330
	11th to 20th	Day	32% 21% 34% 12% 1	330
	21st to end	Day	26% 24% 41% 7% 2	363
April	1st to 10th	Day	27% 18% 29% 20% 6%	529
	11th to 20th	Day	24% 22% 33% 17% 4	532
	21st to end	Day	24% 19% 31% 20% 5% 1	540
May	1st to 10th	Day	20% 16% 35% 21% 7%	645
	11th to 20th	Day	18% 13% 32% 23% 11% 3	775
	21st to end	Day	15% 9% 34% 25% 14% 3	844
June	1st to 10th	Day	12% 6% 22% 32% 23% 5%	780
	11th to 20th	Day	7% 4 22% 37% 25% 4	780
	21st to end	Day	6% 4 28% 37% 21% 4	780
July	1st to 10th	Day	11% 3 15% 34% 29% 8%	771
	11th to 20th	Day	6% 3 15% 35% 31% 10%	768
	21st to end	Day	9% 1 13% 33% 32% 12%	845
August	1st to 10th	Day	9% 2 15% 39% 29% 6%	726
	11th to 20th	Day	12% 2 15% 32% 31% 8%	612
	21st to end	Day	9% 3 13% 30% 31% 14%	583
September	1st to 10th	Day	10% 3 12% 35% 31% 9%	530
	11th to 20th	Day	9% 3 17% 32% 29% 9%	505
	21st to end	Day	9% 9% 26% 30% 22% 4	330
October	1st to 10th	Day	9% 8% 28% 35% 16% 3	330
	11th to 20th	Day	15% 15% 34% 25% 10% 1	330
	21st to end	Day	29% 15% 33% 18% 4	363
November	1st to 10th	Day	18% 17% 28% 29% 7% 1	330
	11th to 20th	Day	19% 19% 35% 19% 7% 1	330
	21st to end	Day	30% 16% 28% 17% 8% 2	330
December	1st to 10th	Day	18% 24% 34% 17% 5% 2	330
	11th to 20th	Day	25% 20% 31% 18% 6% 1	330
	21st to end	Day	27% 22% 36% 13% 2	363
January	1st to 10th	Night	21% 17% 33% 24% 5%	1050
	11th to 20th	Night	21% 19% 35% 20% 4	1050
	21st to end	Night	20% 18% 37% 22% 3	1155
February	1st to 10th	Night	21% 16% 38% 23% 3	1050
	11th to 20th	Night	24% 18% 37% 20% 2	961
	21st to end	Night	22% 18% 35% 23% 2	661
March	1st to 10th	Night	20% 17% 35% 26% 3	630
	11th to 20th	Night	25% 14% 32% 25% 5%	630
	21st to end	Night	22% 14% 38% 22% 5%	693
April	1st to 10th	Night	16% 14% 40% 26% 4	630
	11th to 20th	Night	19% 15% 34% 26% 6%	623
	21st to end	Night	22% 11% 37% 22% 7%	630
May	1st to 10th	Night	16% 8% 31% 36% 9%	630
	11th to 20th	Night	17% 7% 27% 31% 17% 1	621
	21st to end	Night	15% 6% 24% 36% 17% 2	683
June	1st to 10th	Night	10% 4 17% 38% 29% 2	630
	11th to 20th	Night	6% 2 21% 44% 25% 2	630
	21st to end	Night	3 2 19% 45% 30% 2	630
July	1st to 10th	Night	7% 1 10% 39% 37% 6%	615
	11th to 20th	Night	4 1 10% 39% 41% 6%	612
	21st to end	Night	6% 2 10% 38% 39% 5%	687
August	1st to 10th	Night	6% 2 8% 45% 34% 5%	597
	11th to 20th	Night	8% 2 12% 41% 35% 3	594
	21st to end	Night	7% 1 11% 39% 37% 5%	660
September	1st to 10th	Night	9% 2 14% 38% 33% 3	600
	11th to 20th	Night	11% 1 12% 40% 31% 5%	600
	21st to end	Night	10% 4 21% 37% 25% 3	683
October	1st to 10th	Night	8% 4 23% 37% 25% 3	800
	11th to 20th	Night	14% 10% 31% 34% 12% 1	800
	21st to end	Night	22% 11% 30% 29% 8%	880
November	1st to 10th	Night	15% 8% 35% 32% 10%	820
	11th to 20th	Night	17% 12% 31% 32% 8%	840
	21st to end	Night	23% 13% 28% 28% 9%	1014
December	1st to 10th	Night	20% 15% 32% 26% 6%	1050
	11th to 20th	Night	24% 13% 30% 28% 4	1050
	21st to end	Night	25% 18% 31% 22% 4	1155

Page generated at 2026-07-28 02:25:27. Version ac07

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