Caney Ridge Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caney Ridge Observatory clear sky chart from 2005-11-06 to 2025-03-27.

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% 9% 3 8% 5% 5% 5% 4 6% 7% 34%	109526
	Night	12% 9% 3 8% 5% 4 4 4 5% 7% 37%	109827
Transparency	Day	45% 7% 11% 21% 14% 3	113268
	Night	44% 6% 11% 21% 14% 3	114224
Seeing	Day	21% 14% 24% 22% 14% 6%	15456
	Night	19% 11% 22% 29% 16% 2	25623

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	11% 15% 6% 15% 7% 4 3 3 4 6% 26%	4056
	11th to 20th	Day	11% 14% 6% 14% 6% 6% 3 3 3 3 32%	4060
	21st to end	Day	13% 12% 6% 9% 4 4 4 3 5% 6% 34%	4466
February	1st to 10th	Day	14% 13% 5% 11% 6% 4 4 3 5% 5% 30%	1830
	11th to 20th	Day	18% 12% 5% 9% 6% 5% 4 3 5% 5% 28%	1948
	21st to end	Day	17% 12% 4 9% 5% 4 4 3 5% 6% 31%	1650
March	1st to 10th	Day	18% 14% 4 8% 4 4 3 3 5% 6% 32%	3451
	11th to 20th	Day	12% 8% 3 7% 4 4 4 3 5% 6% 43%	3590
	21st to end	Day	15% 9% 3 6% 5% 5% 4 4 5% 7% 38%	3881
April	1st to 10th	Day	11% 9% 4 7% 4 4 5% 5% 5% 8% 37%	2090
	11th to 20th	Day	13% 9% 3 5% 5% 4 4 3 5% 7% 41%	2328
	21st to end	Day	15% 9% 2 7% 5% 4 4 3 5% 8% 38%	2470
May	1st to 10th	Day	14% 10% 4 10% 6% 6% 6% 5% 6% 6% 27%	4082
	11th to 20th	Day	15% 9% 4 9% 5% 6% 6% 5% 6% 6% 29%	4081
	21st to end	Day	9% 6% 2 7% 6% 6% 6% 6% 8% 10% 34%	4476
June	1st to 10th	Day	9% 7% 3 7% 6% 5% 7% 5% 7% 9% 35%	2470
	11th to 20th	Day	7% 6% 3 7% 7% 6% 6% 6% 8% 10% 35%	2470
	21st to end	Day	8% 6% 2 7% 6% 6% 6% 6% 7% 10% 36%	2470
July	1st to 10th	Day	7% 6% 2 6% 6% 6% 7% 6% 9% 10% 36%	4120
	11th to 20th	Day	10% 6% 2 6% 6% 6% 6% 6% 8% 10% 34%	4120
	21st to end	Day	15% 10% 4 11% 8% 7% 7% 5% 6% 7% 19%	4466
August	1st to 10th	Day	9% 6% 3 8% 7% 7% 7% 7% 8% 10% 29%	4104
	11th to 20th	Day	8% 7% 2 8% 6% 6% 7% 5% 8% 11% 32%	4044
	21st to end	Day	6% 4 2 6% 4 5% 5% 5% 6% 10% 46%	4312
September	1st to 10th	Day	11% 6% 2 7% 5% 5% 5% 4 7% 8% 40%	2090
	11th to 20th	Day	13% 8% 3 7% 6% 5% 5% 4 6% 8% 38%	2090
	21st to end	Day	19% 7% 2 6% 4 4 4 3 5% 7% 39%	2090
October	1st to 10th	Day	13% 5% 3 5% 4 4 5% 3 6% 7% 46%	2038
	11th to 20th	Day	12% 7% 2 6% 4 3 4 3 5% 5% 48%	1900
	21st to end	Day	16% 10% 2 5% 3 3 3 3 4 6% 44%	2090
November	1st to 10th	Day	11% 7% 2 4 3 4 3 3 5% 7% 50%	1824
	11th to 20th	Day	11% 11% 2 7% 5% 4 3 4 6% 7% 41%	1800
	21st to end	Day	13% 10% 3 8% 4 3 3 3 5% 7% 40%	1800
December	1st to 10th	Day	11% 11% 5% 11% 6% 5% 5% 3 4 4 35%	2930
	11th to 20th	Day	15% 15% 6% 9% 4 4 4 4 6% 7% 26%	3373
	21st to end	Day	11% 13% 5% 10% 6% 6% 7% 5% 7% 6% 23%	4466
January	1st to 10th	Night	12% 14% 6% 16% 9% 5% 5% 3 4 4 22%	5889
	11th to 20th	Night	16% 12% 4 11% 8% 4 3 2 4 4 32%	5900
	21st to end	Night	13% 11% 4 8% 5% 5% 5% 3 4 5% 37%	6490
February	1st to 10th	Night	14% 12% 5% 9% 5% 4 4 3 5% 6% 33%	2565
	11th to 20th	Night	20% 11% 4 10% 5% 6% 4 3 4 4 28%	2338
	21st to end	Night	15% 15% 5% 9% 5% 4 4 4 4 6% 29%	1980
March	1st to 10th	Night	18% 15% 4 7% 5% 3 4 3 4 5% 33%	3622
	11th to 20th	Night	11% 9% 3 5% 4 3 4 4 5% 7% 45%	3590
	21st to end	Night	12% 10% 3 6% 5% 4 4 3 5% 6% 41%	3890
April	1st to 10th	Night	11% 10% 3 6% 4 4 4 4 6% 7% 41%	2090
	11th to 20th	Night	12% 8% 3 6% 5% 4 4 4 6% 6% 42%	1816
	21st to end	Night	13% 7% 3 6% 4 4 4 4 6% 8% 40%	1710
May	1st to 10th	Night	13% 9% 4 9% 7% 6% 5% 5% 6% 7% 31%	2813
	11th to 20th	Night	14% 9% 3 7% 5% 4 4 4 6% 8% 35%	2812
	21st to end	Night	8% 7% 3 8% 6% 6% 5% 4 7% 10% 38%	3079
June	1st to 10th	Night	9% 6% 2 5% 4 4 6% 4 7% 11% 42%	1710
	11th to 20th	Night	5% 6% 2 6% 4 4 6% 5% 9% 12% 42%	1710
	21st to end	Night	7% 6% 2 7% 5% 5% 6% 5% 7% 11% 39%	1710
July	1st to 10th	Night	7% 5% 2 6% 5% 4 6% 5% 9% 12% 39%	2840
	11th to 20th	Night	8% 6% 2 5% 4 4 5% 5% 7% 10% 44%	2840
	21st to end	Night	11% 11% 4 10% 6% 6% 6% 4 7% 10% 26%	3087
August	1st to 10th	Night	8% 6% 2 8% 6% 5% 5% 6% 8% 10% 35%	2825
	11th to 20th	Night	8% 7% 3 8% 6% 5% 6% 4 7% 9% 37%	2785
	21st to end	Night	4 4 1 5% 3 3 4 4 6% 9% 57%	3305
September	1st to 10th	Night	11% 7% 3 5% 4 5% 4 3 5% 7% 46%	2090
	11th to 20th	Night	13% 7% 2 6% 3 3 4 4 5% 7% 45%	2090
	21st to end	Night	13% 6% 2 5% 5% 4 4 4 5% 6% 46%	2090
October	1st to 10th	Night	13% 5% 2 5% 3 4 4 3 4 6% 51%	2142
	11th to 20th	Night	12% 7% 2 6% 4 4 4 4 4 6% 47%	2280
	21st to end	Night	13% 9% 3 6% 5% 3 3 3 4 6% 47%	2508
November	1st to 10th	Night	12% 7% 2 5% 4 3 4 3 5% 5% 50%	2469
	11th to 20th	Night	12% 10% 3 7% 4 4 4 3 4 7% 43%	2600
	21st to end	Night	12% 10% 3 6% 4 3 4 4 5% 6% 43%	2600
December	1st to 10th	Night	11% 10% 4 12% 6% 5% 5% 4 5% 5% 34%	4250
	11th to 20th	Night	15% 12% 6% 12% 5% 4 4 3 5% 6% 28%	4822
	21st to end	Night	10% 13% 6% 11% 6% 5% 5% 5% 6% 9% 24%	6490

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	61% 4 5% 18% 11% 1	4057
	11th to 20th	Day	57% 5% 5% 13% 18% 2	4060
	21st to end	Day	50% 5% 7% 20% 17% 1	4466
February	1st to 10th	Day	56% 5% 7% 17% 14% 1	1830
	11th to 20th	Day	57% 5% 8% 16% 12% 2	1958
	21st to end	Day	53% 4 8% 15% 14% 4	1650
March	1st to 10th	Day	53% 5% 8% 18% 13% 4	3451
	11th to 20th	Day	41% 6% 7% 23% 19% 4	3590
	21st to end	Day	45% 6% 9% 26% 12% 2	3881
April	1st to 10th	Day	44% 7% 10% 21% 14% 3	2090
	11th to 20th	Day	42% 6% 9% 21% 19% 4	2328
	21st to end	Day	46% 6% 12% 24% 11% 2	2470
May	1st to 10th	Day	54% 8% 11% 16% 10% 1	4120
	11th to 20th	Day	51% 8% 10% 22% 7% 1	4085
	21st to end	Day	39% 10% 16% 20% 13% 2	4489
June	1st to 10th	Day	41% 9% 15% 22% 12% 1	2470
	11th to 20th	Day	40% 11% 15% 18% 15% 1	2470
	21st to end	Day	41% 9% 14% 20% 15% 2	2470
July	1st to 10th	Day	39% 9% 21% 18% 11% 1	4055
	11th to 20th	Day	40% 8% 15% 29% 7% 1	4051
	21st to end	Day	60% 8% 9% 14% 8% 1	4324
August	1st to 10th	Day	45% 9% 16% 22% 8%	4091
	11th to 20th	Day	42% 8% 15% 23% 10% 1	4083
	21st to end	Day	30% 7% 17% 32% 12% 1	4312
September	1st to 10th	Day	39% 8% 13% 21% 14% 5%	2090
	11th to 20th	Day	43% 7% 9% 24% 16% 2	2090
	21st to end	Day	45% 6% 11% 21% 16% 2	2090
October	1st to 10th	Day	29% 5% 8% 21% 33% 5%	3389
	11th to 20th	Day	29% 3 10% 24% 19% 15%	3140
	21st to end	Day	30% 4 8% 31% 15% 13%	3428
November	1st to 10th	Day	34% 5% 8% 22% 26% 4	1824
	11th to 20th	Day	42% 5% 7% 21% 20% 5%	1800
	21st to end	Day	44% 5% 10% 20% 19% 3	1800
December	1st to 10th	Day	52% 5% 5% 20% 17% 1	2930
	11th to 20th	Day	56% 5% 9% 16% 12% 2	3370
	21st to end	Day	56% 8% 11% 18% 7% 1	4466
January	1st to 10th	Night	65% 5% 5% 15% 9% 1	5889
	11th to 20th	Night	56% 5% 5% 14% 17% 3	5900
	21st to end	Night	49% 5% 7% 21% 17% 1	6490
February	1st to 10th	Night	52% 4 11% 19% 13% 1	2565
	11th to 20th	Night	60% 5% 6% 16% 10% 3	2339
	21st to end	Night	56% 5% 8% 16% 11% 4	1980
March	1st to 10th	Night	55% 3 8% 18% 15% 2	3622
	11th to 20th	Night	38% 7% 8% 29% 12% 7%	3590
	21st to end	Night	42% 6% 11% 23% 17% 1	3890
April	1st to 10th	Night	41% 7% 11% 22% 15% 3	2090
	11th to 20th	Night	40% 5% 11% 21% 18% 5%	1816
	21st to end	Night	41% 6% 14% 27% 11% 1	1710
May	1st to 10th	Night	49% 11% 13% 20% 7% 1	2840
	11th to 20th	Night	45% 9% 14% 25% 7%	2813
	21st to end	Night	37% 12% 15% 23% 11% 2	3087
June	1st to 10th	Night	35% 10% 19% 20% 15% 2	1710
	11th to 20th	Night	32% 12% 18% 21% 14% 2	1710
	21st to end	Night	38% 9% 15% 21% 14% 3	1710
July	1st to 10th	Night	35% 9% 22% 23% 9% 1	2795
	11th to 20th	Night	34% 7% 19% 30% 8% 2	2786
	21st to end	Night	51% 10% 13% 17% 8% 1	2988
August	1st to 10th	Night	41% 8% 18% 25% 8%	2814
	11th to 20th	Night	42% 8% 15% 25% 10%	2812
	21st to end	Night	24% 6% 16% 36% 18% 1	3305
September	1st to 10th	Night	38% 7% 14% 20% 16% 5%	2090
	11th to 20th	Night	37% 7% 11% 23% 20% 2	2090
	21st to end	Night	37% 7% 12% 23% 18% 2	2090
October	1st to 10th	Night	30% 5% 9% 21% 31% 5%	3571
	11th to 20th	Night	31% 4 7% 23% 21% 14%	3779
	21st to end	Night	26% 3 6% 30% 21% 14%	4120
November	1st to 10th	Night	37% 5% 8% 21% 24% 6%	2469
	11th to 20th	Night	42% 4 7% 19% 20% 7%	2600
	21st to end	Night	42% 5% 7% 25% 18% 4	2600
December	1st to 10th	Night	52% 5% 7% 21% 13% 1	4250
	11th to 20th	Night	57% 4 9% 18% 10% 1	4824
	21st to end	Night	54% 8% 13% 15% 11% 1	6490

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	30% 28% 29% 10% 3	300
	11th to 20th	Day	40% 26% 23% 9% 2	300
	21st to end	Day	28% 33% 28% 8% 2	330
February	1st to 10th	Day	28% 27% 33% 8% 3	300
	11th to 20th	Day	48% 26% 20% 4 2	300
	21st to end	Day	35% 27% 32% 5% 1	249
March	1st to 10th	Day	30% 21% 26% 17% 6%	440
	11th to 20th	Day	26% 23% 32% 15% 2 1	500
	21st to end	Day	32% 20% 27% 15% 5%	530
April	1st to 10th	Day	28% 19% 25% 17% 9% 2	460
	11th to 20th	Day	21% 19% 29% 19% 10% 2	452
	21st to end	Day	24% 16% 27% 22% 8% 2	460
May	1st to 10th	Day	23% 19% 28% 17% 9% 4	463
	11th to 20th	Day	19% 10% 26% 28% 11% 7%	487
	21st to end	Day	16% 7% 22% 27% 17% 10%	529
June	1st to 10th	Day	12% 6% 28% 27% 19% 8%	490
	11th to 20th	Day	9% 6% 22% 29% 23% 11%	490
	21st to end	Day	11% 6% 26% 29% 17% 10%	490
July	1st to 10th	Day	13% 5% 20% 24% 23% 15%	485
	11th to 20th	Day	8% 4 15% 32% 26% 14%	484
	21st to end	Day	13% 4 17% 28% 25% 12%	532
August	1st to 10th	Day	13% 5% 19% 29% 22% 13%	486
	11th to 20th	Day	15% 5% 16% 28% 23% 13%	479
	21st to end	Day	11% 3 13% 28% 27% 18%	539
September	1st to 10th	Day	10% 6% 19% 25% 30% 10%	490
	11th to 20th	Day	14% 4 16% 28% 27% 12%	490
	21st to end	Day	21% 11% 19% 24% 20% 5%	490
October	1st to 10th	Day	19% 6% 19% 28% 20% 7%	490
	11th to 20th	Day	18% 14% 26% 23% 16% 2	490
	21st to end	Day	23% 13% 25% 25% 11% 2	539
November	1st to 10th	Day	19% 15% 32% 22% 10% 2	362
	11th to 20th	Day	24% 19% 33% 17% 6%	300
	21st to end	Day	25% 21% 32% 18% 4 1	300
December	1st to 10th	Day	32% 22% 33% 12% 2	300
	11th to 20th	Day	28% 17% 34% 15% 4 1	300
	21st to end	Day	26% 25% 32% 13% 4	330
January	1st to 10th	Night	26% 20% 29% 22% 4	800
	11th to 20th	Night	30% 21% 27% 20% 3	800
	21st to end	Night	22% 20% 34% 22% 3	880
February	1st to 10th	Night	23% 19% 31% 24% 3	800
	11th to 20th	Night	32% 21% 28% 17% 1	783
	21st to end	Night	29% 21% 30% 18% 2	660
March	1st to 10th	Night	23% 18% 29% 25% 4	800
	11th to 20th	Night	26% 16% 29% 23% 6% 1	800
	21st to end	Night	22% 18% 28% 25% 7%	863
April	1st to 10th	Night	20% 16% 31% 26% 7%	760
	11th to 20th	Night	18% 14% 27% 28% 11% 1	630
	21st to end	Night	18% 8% 33% 32% 8% 1	570
May	1st to 10th	Night	15% 13% 24% 34% 12% 2	570
	11th to 20th	Night	16% 6% 20% 38% 18% 2	561
	21st to end	Night	12% 3 15% 36% 28% 5%	617
June	1st to 10th	Night	9% 4 16% 39% 28% 3	570
	11th to 20th	Night	6% 2 15% 38% 33% 6%	570
	21st to end	Night	10% 3 15% 41% 27% 4	570
July	1st to 10th	Night	12% 2 8% 34% 39% 5%	555
	11th to 20th	Night	11% 1 9% 32% 43% 5%	552
	21st to end	Night	10% 3 9% 33% 38% 7%	624
August	1st to 10th	Night	10% 3 7% 36% 40% 5%	567
	11th to 20th	Night	11% 3 8% 39% 34% 6%	564
	21st to end	Night	9% 3 5% 34% 39% 9%	661
September	1st to 10th	Night	13% 5% 9% 30% 38% 5%	760
	11th to 20th	Night	17% 3 13% 30% 32% 6%	760
	21st to end	Night	16% 5% 18% 33% 25% 3	760
October	1st to 10th	Night	15% 6% 18% 31% 25% 5%	760
	11th to 20th	Night	18% 9% 22% 33% 17% 2	760
	21st to end	Night	20% 11% 23% 33% 13% 1	836
November	1st to 10th	Night	16% 8% 24% 33% 17% 2	780
	11th to 20th	Night	17% 17% 25% 29% 11% 1	800
	21st to end	Night	20% 16% 24% 31% 9% 1	800
December	1st to 10th	Night	26% 15% 29% 24% 6%	800
	11th to 20th	Night	23% 15% 28% 28% 5% 1	800
	21st to end	Night	24% 17% 27% 27% 4	880

Page generated at 2025-03-24 09:04:31. Version ac07

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