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 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	11% 9% 4 8% 6% 5% 5% 4 6% 8% 34%	138202
	Night	11% 9% 4 9% 5% 5% 5% 4 5% 7% 36%	134824
Transparency	Day	46% 6% 11% 21% 14% 2	141900
	Night	45% 6% 11% 21% 14% 3	139198
Seeing	Day	21% 14% 25% 21% 13% 6%	17300
	Night	19% 11% 22% 29% 16% 2	27339

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	12% 15% 5% 13% 6% 4 4 3 4 6% 28%	5258
	11th to 20th	Day	9% 13% 6% 13% 6% 6% 3 3 3 3 36%	5280
	21st to end	Day	12% 12% 6% 9% 5% 4 4 3 4 6% 34%	5780
February	1st to 10th	Day	14% 12% 5% 11% 6% 4 4 3 5% 5% 30%	1922
	11th to 20th	Day	18% 12% 4 9% 6% 5% 4 3 6% 5% 29%	2048
	21st to end	Day	17% 12% 4 10% 5% 4 4 3 5% 5% 31%	1730
March	1st to 10th	Day	13% 14% 6% 9% 5% 4 4 3 5% 6% 32%	4909
	11th to 20th	Day	10% 9% 4 6% 4 4 4 4 5% 7% 43%	5090
	21st to end	Day	14% 8% 3 7% 5% 5% 5% 4 5% 7% 38%	5586
April	1st to 10th	Day	11% 9% 4 7% 4 4 5% 4 5% 7% 38%	2310
	11th to 20th	Day	12% 8% 3 6% 5% 4 4 3 5% 7% 42%	2576
	21st to end	Day	14% 9% 3 7% 5% 4 4 4 5% 8% 37%	2730
May	1st to 10th	Day	12% 10% 4 9% 5% 6% 6% 5% 6% 7% 29%	7616
	11th to 20th	Day	12% 7% 3 8% 6% 6% 6% 5% 7% 7% 33%	7626
	21st to end	Day	12% 8% 3 10% 7% 6% 6% 5% 7% 9% 25%	8391
June	1st to 10th	Day	9% 7% 3 7% 6% 5% 7% 5% 7% 9% 35%	2730
	11th to 20th	Day	6% 6% 3 7% 7% 6% 7% 6% 8% 10% 34%	2730
	21st to end	Day	8% 6% 2 7% 6% 6% 6% 6% 8% 10% 36%	2730
July	1st to 10th	Day	7% 6% 2 7% 5% 6% 7% 5% 8% 9% 38%	6030
	11th to 20th	Day	9% 6% 3 8% 6% 7% 7% 6% 9% 11% 28%	6030
	21st to end	Day	12% 9% 4 10% 8% 7% 7% 6% 7% 8% 22%	6554
August	1st to 10th	Day	9% 6% 3 8% 6% 7% 7% 6% 8% 10% 29%	4234
	11th to 20th	Day	8% 7% 2 8% 6% 6% 7% 5% 8% 11% 31%	4174
	21st to end	Day	6% 4 2 6% 4 5% 5% 5% 7% 10% 47%	4448
September	1st to 10th	Day	11% 6% 2 7% 5% 5% 4 4 7% 8% 40%	2200
	11th to 20th	Day	12% 7% 3 7% 6% 5% 5% 4 6% 8% 39%	2200
	21st to end	Day	19% 7% 2 6% 4 4 4 4 5% 7% 38%	2200
October	1st to 10th	Day	13% 5% 3 5% 4 4 5% 2 6% 7% 47%	2145
	11th to 20th	Day	12% 7% 2 5% 4 3 4 3 5% 6% 49%	2000
	21st to end	Day	16% 10% 3 6% 4 3 3 3 4 6% 43%	2200
November	1st to 10th	Day	10% 8% 2 4 3 4 3 4 5% 7% 50%	1917
	11th to 20th	Day	11% 10% 2 7% 5% 4 3 4 6% 7% 42%	1890
	21st to end	Day	13% 10% 3 8% 4 3 3 3 5% 7% 39%	1890
December	1st to 10th	Day	11% 12% 5% 11% 6% 5% 5% 3 4 5% 35%	3020
	11th to 20th	Day	15% 15% 6% 9% 4 4 4 4 6% 7% 26%	3463
	21st to end	Day	11% 13% 5% 10% 6% 6% 7% 5% 7% 6% 23%	4565
January	1st to 10th	Night	12% 13% 6% 14% 8% 5% 5% 3 4 5% 26%	7635
	11th to 20th	Night	14% 12% 4 11% 7% 4 3 2 4 4 35%	7680
	21st to end	Night	13% 11% 4 10% 6% 5% 5% 3 4 5% 34%	8401
February	1st to 10th	Night	14% 12% 5% 9% 5% 4 4 3 5% 6% 33%	2693
	11th to 20th	Night	20% 11% 4 10% 5% 6% 4 3 4 4 28%	2458
	21st to end	Night	15% 15% 5% 10% 5% 4 4 4 4 6% 28%	2076
March	1st to 10th	Night	14% 14% 4 7% 4 4 4 3 4 5% 36%	5164
	11th to 20th	Night	10% 8% 3 5% 4 3 3 3 5% 7% 49%	5090
	21st to end	Night	10% 10% 3 7% 5% 5% 5% 4 6% 7% 38%	5588
April	1st to 10th	Night	11% 10% 3 6% 4 4 4 4 5% 7% 41%	2310
	11th to 20th	Night	11% 8% 3 6% 5% 4 4 4 6% 7% 43%	2009
	21st to end	Night	13% 7% 3 6% 4 4 4 4 6% 8% 40%	1890
May	1st to 10th	Night	12% 8% 3 8% 6% 5% 5% 5% 6% 10% 31%	5237
	11th to 20th	Night	10% 7% 3 8% 6% 5% 6% 5% 7% 8% 35%	5234
	21st to end	Night	14% 10% 4 11% 7% 6% 6% 3 6% 8% 26%	5761
June	1st to 10th	Night	8% 6% 2 6% 4 4 5% 4 7% 10% 42%	1890
	11th to 20th	Night	6% 6% 2 6% 4 5% 6% 5% 9% 11% 40%	1890
	21st to end	Night	7% 6% 2 7% 5% 5% 6% 5% 8% 11% 38%	1890
July	1st to 10th	Night	7% 6% 2 6% 5% 5% 6% 5% 9% 11% 38%	4148
	11th to 20th	Night	7% 6% 2 7% 5% 5% 6% 5% 8% 12% 36%	4147
	21st to end	Night	10% 10% 4 10% 6% 6% 6% 5% 7% 9% 26%	4517
August	1st to 10th	Night	8% 6% 2 8% 6% 5% 5% 6% 8% 10% 35%	2915
	11th to 20th	Night	8% 7% 3 8% 5% 5% 6% 4 7% 9% 37%	2875
	21st to end	Night	4 4 1 5% 3 4 4 4 6% 9% 56%	3410
September	1st to 10th	Night	12% 7% 2 5% 4 5% 4 3 5% 7% 46%	2200
	11th to 20th	Night	13% 7% 2 6% 3 3 4 4 5% 8% 46%	2200
	21st to end	Night	13% 7% 2 5% 5% 4 4 4 5% 6% 45%	2200
October	1st to 10th	Night	12% 5% 2 5% 3 4 4 3 4 6% 52%	2255
	11th to 20th	Night	12% 6% 2 6% 4 4 4 4 4 6% 48%	2400
	21st to end	Night	13% 9% 3 6% 4 3 3 3 4 5% 47%	2640
November	1st to 10th	Night	11% 7% 3 5% 4 3 4 3 4 5% 51%	2596
	11th to 20th	Night	12% 10% 3 7% 3 4 4 3 4 7% 43%	2730
	21st to end	Night	12% 10% 3 7% 4 4 4 4 5% 6% 42%	2730
December	1st to 10th	Night	11% 10% 4 12% 6% 5% 5% 4 5% 5% 34%	4380
	11th to 20th	Night	14% 12% 6% 12% 5% 4 4 3 5% 6% 29%	4952
	21st to end	Night	10% 13% 6% 11% 6% 5% 5% 5% 6% 9% 24%	6633

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% 4 8% 17% 12% 1	5259
	11th to 20th	Day	54% 4 4 15% 20% 3	5280
	21st to end	Day	51% 4 7% 23% 14% 1	5780
February	1st to 10th	Day	56% 5% 6% 17% 14% 1	1922
	11th to 20th	Day	57% 5% 8% 17% 12% 2	2058
	21st to end	Day	54% 4 8% 16% 13% 4	1730
March	1st to 10th	Day	53% 4 6% 15% 15% 6%	4909
	11th to 20th	Day	40% 5% 6% 19% 24% 6%	5090
	21st to end	Day	45% 5% 9% 26% 14% 1	5586
April	1st to 10th	Day	43% 6% 12% 22% 14% 3	2310
	11th to 20th	Day	41% 5% 10% 22% 19% 4	2576
	21st to end	Day	46% 6% 11% 24% 11% 2	2730
May	1st to 10th	Day	51% 6% 11% 19% 12% 1	7651
	11th to 20th	Day	47% 7% 13% 23% 10%	7630
	21st to end	Day	51% 9% 12% 15% 10% 3	8405
June	1st to 10th	Day	41% 9% 15% 21% 13% 1	2730
	11th to 20th	Day	40% 10% 16% 19% 14% 1	2730
	21st to end	Day	40% 9% 14% 21% 14% 2	2730
July	1st to 10th	Day	40% 8% 18% 20% 13% 1	5965
	11th to 20th	Day	45% 10% 18% 22% 5% 1	5961
	21st to end	Day	56% 8% 11% 17% 8%	6370
August	1st to 10th	Day	45% 9% 16% 22% 8%	4221
	11th to 20th	Day	42% 8% 15% 23% 10% 1	4213
	21st to end	Day	30% 7% 17% 32% 13% 1	4448
September	1st to 10th	Day	38% 8% 14% 21% 15% 5%	2200
	11th to 20th	Day	42% 7% 9% 25% 16% 2	2200
	21st to end	Day	45% 6% 12% 20% 16% 2	2200
October	1st to 10th	Day	29% 4 8% 21% 33% 5%	3496
	11th to 20th	Day	28% 3 10% 24% 20% 15%	3240
	21st to end	Day	31% 4 7% 31% 15% 12%	3538
November	1st to 10th	Day	34% 5% 9% 22% 26% 4	1917
	11th to 20th	Day	41% 5% 7% 22% 20% 4	1890
	21st to end	Day	44% 4 9% 21% 18% 3	1890
December	1st to 10th	Day	52% 5% 5% 20% 16% 1	3020
	11th to 20th	Day	56% 5% 9% 16% 12% 2	3460
	21st to end	Day	56% 8% 11% 18% 7% 1	4565
January	1st to 10th	Night	61% 5% 9% 18% 7% 1	7636
	11th to 20th	Night	53% 4 5% 16% 19% 3	7680
	21st to end	Night	53% 4 6% 20% 15% 2	8401
February	1st to 10th	Night	52% 4 11% 19% 13% 1	2693
	11th to 20th	Night	59% 5% 6% 17% 10% 3	2459
	21st to end	Night	57% 5% 7% 16% 11% 3	2076
March	1st to 10th	Night	52% 3 6% 20% 15% 4	5164
	11th to 20th	Night	33% 5% 7% 26% 22% 7%	5090
	21st to end	Night	44% 5% 11% 24% 14% 1	5588
April	1st to 10th	Night	41% 7% 12% 23% 15% 3	2310
	11th to 20th	Night	40% 5% 11% 22% 17% 5%	2009
	21st to end	Night	42% 6% 13% 26% 12% 1	1890
May	1st to 10th	Night	47% 9% 13% 21% 10%	5264
	11th to 20th	Night	44% 8% 15% 22% 10%	5235
	21st to end	Night	54% 9% 12% 16% 7% 1	5771
June	1st to 10th	Night	35% 9% 18% 21% 15% 1	1890
	11th to 20th	Night	34% 12% 17% 21% 13% 2	1890
	21st to end	Night	37% 9% 15% 22% 14% 3	1890
July	1st to 10th	Night	37% 10% 18% 26% 9% 1	4105
	11th to 20th	Night	39% 9% 22% 22% 6% 2	4096
	21st to end	Night	52% 9% 14% 17% 9%	4387
August	1st to 10th	Night	41% 8% 19% 24% 7%	2904
	11th to 20th	Night	41% 8% 16% 25% 10%	2902
	21st to end	Night	24% 6% 16% 36% 18% 1	3410
September	1st to 10th	Night	37% 7% 15% 20% 17% 5%	2200
	11th to 20th	Night	36% 7% 11% 24% 20% 2	2200
	21st to end	Night	39% 7% 12% 22% 18% 2	2200
October	1st to 10th	Night	30% 5% 9% 21% 31% 4	3684
	11th to 20th	Night	30% 4 7% 23% 22% 14%	3899
	21st to end	Night	27% 3 6% 29% 21% 13%	4252
November	1st to 10th	Night	37% 4 8% 21% 24% 5%	2596
	11th to 20th	Night	42% 4 7% 20% 21% 6%	2730
	21st to end	Night	43% 5% 7% 25% 17% 3	2730
December	1st to 10th	Night	53% 5% 7% 21% 13% 1	4380
	11th to 20th	Night	56% 4 10% 18% 10% 1	4954
	21st to end	Night	54% 7% 13% 15% 11% 1	6633

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	31% 27% 29% 9% 3	330
	11th to 20th	Day	41% 26% 23% 8% 2	330
	21st to end	Day	31% 32% 27% 7% 2	363
February	1st to 10th	Day	28% 27% 34% 8% 3	330
	11th to 20th	Day	47% 26% 20% 5% 2	330
	21st to end	Day	34% 27% 32% 6% 1	273
March	1st to 10th	Day	30% 21% 28% 16% 5%	477
	11th to 20th	Day	28% 23% 31% 15% 2 1	540
	21st to end	Day	30% 20% 30% 15% 5%	594
April	1st to 10th	Day	28% 20% 26% 17% 8% 2	540
	11th to 20th	Day	22% 19% 31% 18% 9% 2	532
	21st to end	Day	24% 17% 27% 22% 8% 2	540
May	1st to 10th	Day	24% 20% 28% 16% 8% 3	543
	11th to 20th	Day	19% 12% 26% 28% 10% 6%	567
	21st to end	Day	19% 8% 25% 24% 15% 8%	617
June	1st to 10th	Day	11% 7% 29% 26% 20% 7%	570
	11th to 20th	Day	9% 7% 24% 29% 21% 10%	570
	21st to end	Day	11% 6% 25% 29% 19% 10%	570
July	1st to 10th	Day	12% 5% 19% 25% 24% 15%	565
	11th to 20th	Day	10% 4 15% 31% 26% 14%	564
	21st to end	Day	13% 5% 19% 27% 25% 12%	616
August	1st to 10th	Day	14% 5% 18% 28% 22% 12%	526
	11th to 20th	Day	14% 5% 15% 30% 23% 12%	519
	21st to end	Day	11% 4 15% 28% 26% 16%	583
September	1st to 10th	Day	9% 6% 20% 26% 29% 9%	530
	11th to 20th	Day	13% 4 16% 28% 26% 13%	530
	21st to end	Day	22% 11% 20% 24% 18% 5%	530
October	1st to 10th	Day	18% 6% 19% 30% 20% 7%	530
	11th to 20th	Day	17% 13% 28% 23% 16% 2	530
	21st to end	Day	25% 13% 26% 24% 10% 2	583
November	1st to 10th	Day	21% 15% 33% 21% 9% 2	395
	11th to 20th	Day	25% 19% 33% 16% 6%	330
	21st to end	Day	26% 22% 31% 16% 4 1	330
December	1st to 10th	Day	31% 23% 33% 11% 2	330
	11th to 20th	Day	28% 18% 35% 14% 3 1	330
	21st to end	Day	28% 25% 31% 12% 4	363
January	1st to 10th	Night	26% 20% 29% 22% 4	840
	11th to 20th	Night	30% 21% 27% 19% 3	840
	21st to end	Night	23% 20% 34% 21% 2	924
February	1st to 10th	Night	24% 18% 32% 24% 3	840
	11th to 20th	Night	32% 22% 28% 17% 1	823
	21st to end	Night	29% 21% 30% 18% 2	692
March	1st to 10th	Night	23% 18% 30% 25% 4	840
	11th to 20th	Night	26% 16% 29% 22% 6%	840
	21st to end	Night	21% 19% 30% 23% 6%	924
April	1st to 10th	Night	20% 16% 32% 25% 7%	840
	11th to 20th	Night	17% 15% 29% 27% 10% 1	697
	21st to end	Night	18% 9% 33% 31% 9% 1	630
May	1st to 10th	Night	16% 12% 25% 34% 11% 2	630
	11th to 20th	Night	16% 7% 21% 38% 17% 2	621
	21st to end	Night	15% 3 16% 35% 26% 5%	683
June	1st to 10th	Night	10% 4 16% 40% 28% 3	630
	11th to 20th	Night	8% 2 15% 38% 31% 5%	630
	21st to end	Night	10% 3 15% 41% 27% 3	630
July	1st to 10th	Night	12% 2 8% 33% 39% 5%	615
	11th to 20th	Night	10% 2 8% 33% 42% 5%	612
	21st to end	Night	12% 3 10% 32% 37% 7%	687
August	1st to 10th	Night	11% 3 8% 36% 38% 4	597
	11th to 20th	Night	11% 3 8% 38% 35% 6%	594
	21st to end	Night	9% 3 6% 35% 38% 8%	696
September	1st to 10th	Night	13% 5% 10% 31% 37% 5%	800
	11th to 20th	Night	16% 3 13% 30% 33% 6%	800
	21st to end	Night	17% 5% 19% 32% 25% 3	800
October	1st to 10th	Night	14% 7% 18% 31% 25% 5%	800
	11th to 20th	Night	17% 8% 22% 34% 17% 2	800
	21st to end	Night	21% 11% 23% 32% 12% 1	880
November	1st to 10th	Night	17% 8% 25% 32% 16% 2	820
	11th to 20th	Night	18% 17% 25% 29% 10% 1	840
	21st to end	Night	21% 16% 24% 30% 9% 1	840
December	1st to 10th	Night	26% 15% 29% 24% 6%	840
	11th to 20th	Night	23% 15% 29% 27% 5%	840
	21st to end	Night	25% 18% 27% 26% 4	924

Page generated at 2026-07-28 03:25:21. Version ac07

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