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 2024-10-20.

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% 8% 34%	101014
	Night	12% 10% 3 8% 5% 4 4 4 6% 7% 37%	97627
Transparency	Day	46% 7% 11% 21% 13% 2	100827
	Night	45% 7% 11% 21% 13% 2	97484
Seeing	Day	20% 13% 24% 22% 14% 6%	14944
	Night	18% 11% 22% 29% 17% 2	24991

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	13% 15% 5% 16% 5% 4 3 3 5% 6% 25%	2836
	11th to 20th	Day	14% 15% 7% 13% 6% 7% 3 3 4 3 26%	2840
	21st to end	Day	15% 16% 8% 9% 4 4 4 3 4 5% 28%	3124
February	1st to 10th	Day	14% 13% 5% 11% 6% 4 4 3 5% 5% 30%	1738
	11th to 20th	Day	18% 12% 5% 10% 6% 4 4 3 6% 5% 29%	1848
	21st to end	Day	18% 12% 4 10% 5% 4 4 3 5% 5% 30%	1570
March	1st to 10th	Day	18% 15% 4 7% 4 3 3 3 5% 6% 31%	3344
	11th to 20th	Day	12% 8% 3 7% 5% 4 4 3 5% 6% 43%	3480
	21st to end	Day	15% 9% 3 6% 5% 5% 4 4 5% 7% 37%	3815
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	13% 7% 2 6% 4 3 4 3 5% 6% 47%	1890
	21st to end	Day	17% 10% 3 6% 3 3 3 3 4 6% 42%	1980
November	1st to 10th	Day	11% 7% 2 4 3 4 3 4 5% 6% 51%	1731
	11th to 20th	Day	11% 10% 2 7% 5% 4 3 4 5% 7% 42%	1710
	21st to end	Day	13% 9% 2 8% 5% 3 3 3 5% 7% 41%	1710
December	1st to 10th	Day	17% 14% 5% 9% 5% 4 4 3 4 5% 30%	1710
	11th to 20th	Day	13% 14% 5% 9% 4 3 3 4 6% 8% 32%	2153
	21st to end	Day	14% 16% 4 9% 6% 5% 6% 5% 6% 6% 23%	3124
January	1st to 10th	Night	13% 15% 7% 14% 6% 4 4 3 4 4 25%	4109
	11th to 20th	Night	17% 13% 4 9% 7% 4 3 2 4 4 32%	4120
	21st to end	Night	15% 14% 5% 9% 6% 5% 4 3 4 5% 30%	4532
February	1st to 10th	Night	14% 11% 5% 9% 5% 4 4 3 5% 6% 33%	2437
	11th to 20th	Night	20% 11% 4 10% 5% 6% 4 3 4 4 29%	2218
	21st to end	Night	15% 16% 5% 9% 5% 4 4 4 4 6% 27%	1884
March	1st to 10th	Night	18% 15% 3 7% 5% 3 4 3 4 5% 33%	3509
	11th to 20th	Night	12% 9% 3 5% 4 3 4 4 5% 6% 44%	3480
	21st to end	Night	12% 10% 3 6% 5% 4 4 3 5% 6% 42%	3817
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%	2275
	21st to end	Night	13% 9% 3 6% 5% 3 3 3 4 5% 45%	2376
November	1st to 10th	Night	12% 7% 2 5% 4 3 4 3 5% 5% 51%	2342
	11th to 20th	Night	12% 10% 3 7% 3 4 4 3 4 7% 44%	2470
	21st to end	Night	12% 10% 3 6% 3 4 4 4 6% 6% 43%	2470
December	1st to 10th	Night	15% 14% 5% 10% 5% 4 4 4 5% 6% 28%	2470
	11th to 20th	Night	15% 13% 5% 12% 5% 4 3 3 5% 6% 30%	3042
	21st to end	Night	11% 15% 6% 11% 6% 5% 5% 5% 6% 8% 21%	4532

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	59% 5% 6% 16% 12% 2	2837
	11th to 20th	Day	63% 5% 7% 14% 11% 1	2840
	21st to end	Day	57% 6% 7% 16% 14% 1	3124
February	1st to 10th	Day	56% 5% 6% 17% 14% 1	1738
	11th to 20th	Day	56% 5% 8% 17% 12% 2	1858
	21st to end	Day	55% 5% 9% 14% 14% 4	1570
March	1st to 10th	Day	53% 5% 8% 18% 13% 3	3344
	11th to 20th	Day	41% 6% 7% 23% 18% 4	3480
	21st to end	Day	45% 6% 9% 26% 11% 2	3815
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	37% 6% 10% 23% 21% 4	2038
	11th to 20th	Day	38% 5% 10% 23% 20% 4	1890
	21st to end	Day	43% 5% 6% 25% 16% 4	1980
November	1st to 10th	Day	33% 5% 8% 23% 26% 4	1731
	11th to 20th	Day	41% 5% 7% 22% 20% 5%	1710
	21st to end	Day	43% 5% 9% 20% 19% 3	1710
December	1st to 10th	Day	57% 6% 7% 19% 9% 2	1710
	11th to 20th	Day	49% 6% 10% 16% 16% 3	2150
	21st to end	Day	58% 8% 10% 18% 7%	3124
January	1st to 10th	Night	62% 6% 6% 14% 11% 2	4109
	11th to 20th	Night	55% 5% 7% 15% 16% 2	4120
	21st to end	Night	55% 6% 8% 17% 12% 1	4532
February	1st to 10th	Night	52% 4 10% 19% 13% 1	2437
	11th to 20th	Night	58% 5% 6% 17% 11% 3	2219
	21st to end	Night	57% 6% 8% 16% 10% 4	1884
March	1st to 10th	Night	55% 3 8% 17% 14% 2	3509
	11th to 20th	Night	38% 7% 9% 29% 12% 6%	3480
	21st to end	Night	42% 6% 11% 23% 17% 1	3817
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	33% 6% 10% 23% 22% 6%	2142
	11th to 20th	Night	38% 6% 8% 24% 20% 4	2275
	21st to end	Night	41% 5% 5% 24% 19% 6%	2376
November	1st to 10th	Night	36% 5% 8% 21% 25% 6%	2342
	11th to 20th	Night	41% 5% 7% 20% 20% 7%	2470
	21st to end	Night	41% 5% 7% 25% 18% 4	2470
December	1st to 10th	Night	57% 6% 8% 18% 10% 2	2470
	11th to 20th	Night	55% 5% 7% 18% 13% 2	3044
	21st to end	Night	56% 9% 11% 14% 10% 1	4532

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	27% 27% 31% 11% 3	270
	11th to 20th	Day	41% 25% 23% 10% 2	270
	21st to end	Day	29% 31% 29% 8% 3	297
February	1st to 10th	Day	29% 26% 33% 9% 3	270
	11th to 20th	Day	44% 28% 21% 5% 2	270
	21st to end	Day	38% 26% 30% 5% 1	225
March	1st to 10th	Day	28% 21% 27% 17% 6%	403
	11th to 20th	Day	25% 23% 32% 16% 3 1	460
	21st to end	Day	31% 20% 27% 16% 6%	506
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% 3	486
	21st to end	Day	24% 14% 24% 23% 11% 3	495
November	1st to 10th	Day	19% 15% 31% 23% 10% 2	329
	11th to 20th	Day	23% 19% 33% 18% 7%	270
	21st to end	Day	21% 21% 34% 19% 4 1	270
December	1st to 10th	Day	31% 21% 32% 13% 2	270
	11th to 20th	Day	27% 17% 34% 17% 4 1	270
	21st to end	Day	26% 25% 33% 12% 4	297
January	1st to 10th	Night	25% 20% 29% 23% 4	760
	11th to 20th	Night	29% 20% 27% 20% 4	760
	21st to end	Night	23% 20% 32% 22% 3	836
February	1st to 10th	Night	23% 18% 31% 25% 3	760
	11th to 20th	Night	31% 21% 29% 17% 1	743
	21st to end	Night	30% 21% 30% 18% 2	628
March	1st to 10th	Night	23% 18% 29% 25% 5%	760
	11th to 20th	Night	26% 15% 29% 23% 6% 1	760
	21st to end	Night	22% 18% 28% 25% 7%	836
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	759
	21st to end	Night	21% 11% 22% 32% 13% 1	792
November	1st to 10th	Night	17% 7% 23% 33% 18% 2	740
	11th to 20th	Night	17% 17% 25% 29% 11% 1	760
	21st to end	Night	20% 15% 24% 31% 9% 1	760
December	1st to 10th	Night	26% 15% 28% 24% 7%	760
	11th to 20th	Night	21% 15% 28% 29% 6% 1	760
	21st to end	Night	25% 17% 27% 28% 4	836

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