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 2025-03-12.

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%	108761
	Night	13% 7% 2 6% 4 3 3 3 5% 6% 48%	110397
Transparency	Day	37% 6% 11% 25% 18% 4	112409
	Night	35% 6% 11% 25% 19% 4	114889
Seeing	Day	17% 11% 26% 26% 16% 4	15891
	Night	16% 10% 27% 30% 14% 1	25886

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	16% 11% 3 5% 5% 3 3 2 3 4 45%	4077
	11th to 20th	Day	9% 8% 3 7% 4 4 3 3 4 6% 49%	4080
	21st to end	Day	19% 8% 3 7% 3 3 3 2 4 4 45%	4488
February	1st to 10th	Day	17% 10% 4 7% 5% 4 4 3 4 5% 38%	1800
	11th to 20th	Day	16% 10% 3 6% 4 3 4 2 3 6% 43%	1818
	21st to end	Day	16% 10% 3 5% 5% 3 4 3 5% 6% 40%	1695
March	1st to 10th	Day	16% 10% 3 6% 3 3 3 2 4 5% 45%	3546
	11th to 20th	Day	13% 7% 2 5% 3 3 3 3 4 7% 51%	3491
	21st to end	Day	16% 8% 3 9% 5% 4 4 4 5% 6% 36%	3814
April	1st to 10th	Day	14% 7% 2 5% 4 4 4 3 6% 7% 45%	2270
	11th to 20th	Day	17% 8% 3 6% 4 4 4 3 5% 5% 40%	2254
	21st to end	Day	20% 9% 3 7% 5% 4 4 3 5% 4 37%	2280
May	1st to 10th	Day	17% 7% 3 7% 5% 5% 5% 4 6% 7% 35%	3922
	11th to 20th	Day	14% 7% 2 7% 5% 4 5% 3 6% 8% 39%	4082
	21st to end	Day	14% 6% 2 6% 6% 5% 5% 4 6% 9% 37%	4685
June	1st to 10th	Day	8% 6% 2 5% 5% 4 6% 4 7% 9% 44%	2660
	11th to 20th	Day	5% 5% 2 5% 5% 5% 5% 4 7% 10% 46%	2660
	21st to end	Day	5% 4 1 4 4 5% 5% 4 7% 9% 50%	2660
July	1st to 10th	Day	11% 5% 2 5% 4 5% 5% 4 6% 10% 42%	4167
	11th to 20th	Day	5% 3 1 5% 4 5% 5% 4 7% 11% 48%	4120
	21st to end	Day	7% 6% 2 7% 5% 5% 6% 6% 8% 11% 37%	4465
August	1st to 10th	Day	5% 3 1 4 4 3 5% 4 6% 8% 57%	4104
	11th to 20th	Day	11% 5% 2 6% 5% 4 4 4 6% 8% 45%	3865
	21st to end	Day	5% 3 2 5% 4 4 4 4 6% 8% 56%	4180
September	1st to 10th	Day	11% 4 2 5% 4 4 4 3 6% 6% 49%	2280
	11th to 20th	Day	11% 7% 2 5% 5% 4 5% 3 5% 7% 46%	2256
	21st to end	Day	7% 5% 2 5% 4 4 4 3 6% 6% 54%	1991
October	1st to 10th	Day	10% 3 2 5% 3 4 3 3 4 6% 57%	1900
	11th to 20th	Day	14% 5% 2 5% 3 3 3 2 3 5% 55%	1900
	21st to end	Day	18% 6% 2 5% 3 3 3 2 4 5% 48%	2090
November	1st to 10th	Day	15% 6% 2 4 2 3 3 2 3 5% 56%	1958
	11th to 20th	Day	14% 7% 2 5% 2 2 3 3 4 6% 51%	1853
	21st to end	Day	19% 7% 3 5% 4 3 2 3 3 4 47%	1630
December	1st to 10th	Day	11% 10% 2 5% 3 3 3 2 3 4 54%	2610
	11th to 20th	Day	14% 10% 3 6% 4 3 3 3 3 5% 46%	3008
	21st to end	Day	18% 21% 4 7% 4 3 3 2 4 4 29%	4102
January	1st to 10th	Night	15% 9% 5% 8% 4 4 4 3 4 5% 40%	5888
	11th to 20th	Night	10% 7% 2 9% 4 3 4 3 4 5% 48%	5900
	21st to end	Night	18% 10% 4 6% 3 3 3 2 3 5% 45%	6490
February	1st to 10th	Night	17% 9% 3 6% 4 3 3 3 5% 6% 41%	2600
	11th to 20th	Night	16% 7% 3 7% 4 3 3 3 3 5% 44%	2468
	21st to end	Night	16% 7% 3 4 3 3 3 3 5% 6% 46%	1950
March	1st to 10th	Night	20% 9% 2 5% 3 3 3 2 3 4 45%	3529
	11th to 20th	Night	12% 8% 2 5% 3 3 3 3 4 5% 51%	3497
	21st to end	Night	15% 8% 3 7% 4 4 4 4 5% 6% 39%	3817
April	1st to 10th	Night	11% 5% 2 5% 3 3 3 4 5% 7% 52%	1909
	11th to 20th	Night	14% 6% 2 4 3 3 5% 4 5% 7% 47%	1875
	21st to end	Night	19% 7% 2 6% 3 4 4 3 6% 7% 40%	1900
May	1st to 10th	Night	17% 6% 2 5% 4 4 4 3 5% 7% 44%	2962
	11th to 20th	Night	13% 7% 2 6% 4 4 4 4 7% 9% 40%	2823
	21st to end	Night	14% 7% 3 6% 5% 4 4 4 5% 9% 39%	2878
June	1st to 10th	Night	8% 3 2 5% 3 3 4 3 6% 10% 53%	1520
	11th to 20th	Night	4 3 1 3 4 3 3 4 7% 10% 57%	1520
	21st to end	Night	2 3 1 3 4 3 4 3 6% 9% 61%	1520
July	1st to 10th	Night	9% 4 2 5% 4 4 5% 5% 6% 8% 48%	2783
	11th to 20th	Night	3 2 1 4 3 3 4 4 6% 9% 60%	2850
	21st to end	Night	6% 6% 3 6% 5% 4 5% 4 6% 9% 47%	3098
August	1st to 10th	Night	3 2 1 3 3 3 4 4 6% 9% 62%	2836
	11th to 20th	Night	9% 4 2 5% 4 3 4 3 6% 8% 51%	2965
	21st to end	Night	5% 3 1 4 3 3 4 3 5% 7% 62%	3476
September	1st to 10th	Night	8% 4 1 4 4 3 4 3 5% 8% 56%	1900
	11th to 20th	Night	9% 5% 2 5% 3 4 4 3 6% 7% 51%	1919
	21st to end	Night	8% 4 2 5% 3 4 3 3 4 7% 58%	2169
October	1st to 10th	Night	6% 3 1 4 4 3 3 3 5% 7% 60%	2280
	11th to 20th	Night	14% 4 1 4 3 3 3 3 4 5% 56%	2280
	21st to end	Night	17% 6% 2 5% 3 2 2 2 3 5% 50%	2508
November	1st to 10th	Night	12% 6% 2 4 3 3 2 2 3 6% 56%	2340
	11th to 20th	Night	12% 6% 2 4 2 2 3 3 5% 5% 54%	2545
	21st to end	Night	17% 8% 2 4 3 3 3 3 4 6% 48%	2765
December	1st to 10th	Night	12% 9% 2 5% 3 3 3 3 4 6% 50%	4580
	11th to 20th	Night	16% 8% 3 6% 4 3 3 2 3 4 47%	5199
	21st to end	Night	23% 17% 3 7% 4 3 3 3 4 4 29%	6858

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	44% 3 9% 24% 17% 2	4078
	11th to 20th	Day	36% 3 9% 27% 19% 6%	4080
	21st to end	Day	44% 3 7% 18% 19% 8%	4488
February	1st to 10th	Day	48% 5% 11% 22% 12% 2	1800
	11th to 20th	Day	44% 4 11% 21% 17% 4	1827
	21st to end	Day	45% 5% 7% 21% 15% 7%	1695
March	1st to 10th	Day	41% 6% 8% 20% 16% 9%	3546
	11th to 20th	Day	33% 6% 9% 28% 18% 6%	3491
	21st to end	Day	46% 8% 12% 22% 11% 1	3814
April	1st to 10th	Day	38% 7% 11% 23% 19% 2	2270
	11th to 20th	Day	43% 7% 12% 19% 16% 4	2254
	21st to end	Day	50% 5% 9% 20% 13% 2	2280
May	1st to 10th	Day	44% 10% 13% 19% 13% 1	3957
	11th to 20th	Day	41% 10% 14% 23% 11% 1	4086
	21st to end	Day	40% 11% 13% 22% 14% 1	4698
June	1st to 10th	Day	34% 10% 15% 25% 15% 1	2660
	11th to 20th	Day	30% 8% 14% 31% 15% 2	2660
	21st to end	Day	26% 9% 16% 28% 16% 5%	2660
July	1st to 10th	Day	35% 8% 17% 26% 12% 1	4103
	11th to 20th	Day	27% 8% 14% 33% 17% 2	4051
	21st to end	Day	36% 10% 20% 25% 8% 1	4325
August	1st to 10th	Day	23% 7% 19% 28% 21% 2	4090
	11th to 20th	Day	36% 6% 15% 28% 13% 1	3904
	21st to end	Day	26% 7% 13% 37% 14% 4	4179
September	1st to 10th	Day	33% 7% 11% 24% 16% 8%	2280
	11th to 20th	Day	37% 6% 10% 23% 23% 2	2256
	21st to end	Day	29% 6% 9% 28% 25% 3	1991
October	1st to 10th	Day	17% 4 6% 17% 43% 14%	3160
	11th to 20th	Day	21% 2 6% 20% 38% 13%	3140
	21st to end	Day	30% 3 8% 31% 24% 4	3428
November	1st to 10th	Day	32% 4 9% 27% 22% 6%	1958
	11th to 20th	Day	34% 4 8% 23% 23% 8%	1853
	21st to end	Day	42% 4 9% 21% 23% 2	1630
December	1st to 10th	Day	35% 3 8% 33% 19% 1	2610
	11th to 20th	Day	41% 5% 6% 25% 22% 1	3005
	21st to end	Day	57% 6% 8% 18% 9% 1	4102
January	1st to 10th	Night	44% 5% 11% 23% 14% 3	5888
	11th to 20th	Night	36% 5% 9% 23% 24% 2	5900
	21st to end	Night	44% 3 8% 20% 21% 4	6490
February	1st to 10th	Night	43% 5% 12% 24% 14% 3	2600
	11th to 20th	Night	43% 4 10% 21% 19% 3	2469
	21st to end	Night	39% 4 10% 20% 20% 7%	1950
March	1st to 10th	Night	43% 5% 9% 19% 16% 8%	3529
	11th to 20th	Night	35% 6% 10% 25% 20% 4	3497
	21st to end	Night	43% 8% 11% 25% 12% 1	3817
April	1st to 10th	Night	32% 5% 12% 24% 22% 5%	1909
	11th to 20th	Night	35% 6% 10% 24% 19% 6%	1875
	21st to end	Night	43% 6% 11% 23% 15% 2	1900
May	1st to 10th	Night	38% 8% 14% 22% 15% 3	2992
	11th to 20th	Night	36% 12% 15% 24% 13% 2	2824
	21st to end	Night	39% 11% 13% 26% 11%	2886
June	1st to 10th	Night	26% 8% 15% 31% 18% 3	1520
	11th to 20th	Night	20% 8% 15% 34% 20% 3	1520
	21st to end	Night	20% 7% 16% 31% 20% 7%	1520
July	1st to 10th	Night	31% 8% 18% 23% 16% 4	2738
	11th to 20th	Night	20% 7% 12% 38% 22% 2	2796
	21st to end	Night	33% 8% 17% 31% 11%	2999
August	1st to 10th	Night	17% 7% 18% 35% 22% 1	2826
	11th to 20th	Night	30% 7% 17% 29% 14% 2	2992
	21st to end	Night	20% 6% 13% 38% 18% 3	3476
September	1st to 10th	Night	26% 6% 12% 29% 19% 8%	1900
	11th to 20th	Night	32% 7% 10% 23% 24% 5%	1919
	21st to end	Night	27% 5% 11% 22% 32% 4	2169
October	1st to 10th	Night	14% 3 8% 15% 42% 19%	3800
	11th to 20th	Night	21% 3 6% 18% 33% 19%	3779
	21st to end	Night	30% 3 6% 29% 26% 6%	4120
November	1st to 10th	Night	31% 4 9% 25% 24% 7%	2340
	11th to 20th	Night	31% 4 8% 24% 26% 7%	2545
	21st to end	Night	38% 5% 8% 24% 22% 3	2765
December	1st to 10th	Night	36% 4 9% 34% 17% 1	4580
	11th to 20th	Night	43% 3 6% 24% 21% 4	5201
	21st to end	Night	57% 5% 9% 20% 7% 2	6858

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% 25% 34% 15% 2	300
	11th to 20th	Day	30% 22% 36% 9% 2	300
	21st to end	Day	24% 28% 30% 16% 2	330
February	1st to 10th	Day	27% 20% 39% 11% 3	300
	11th to 20th	Day	33% 25% 30% 9% 3	300
	21st to end	Day	34% 20% 36% 8% 2	249
March	1st to 10th	Day	26% 21% 36% 14% 3	300
	11th to 20th	Day	32% 20% 32% 15% 1	273
	21st to end	Day	27% 25% 39% 6% 2	297
April	1st to 10th	Day	25% 20% 29% 20% 6%	450
	11th to 20th	Day	24% 21% 32% 17% 5%	452
	21st to end	Day	25% 18% 32% 19% 5% 1	460
May	1st to 10th	Day	21% 15% 34% 21% 8%	555
	11th to 20th	Day	18% 11% 31% 25% 12% 3	675
	21st to end	Day	12% 9% 36% 24% 15% 4	734
June	1st to 10th	Day	11% 4 22% 33% 24% 6%	680
	11th to 20th	Day	6% 3 21% 40% 27% 5%	680
	21st to end	Day	5% 4 28% 36% 21% 5%	680
July	1st to 10th	Day	12% 3 15% 34% 29% 7%	671
	11th to 20th	Day	6% 2 16% 35% 31% 10%	668
	21st to end	Day	9% 1 13% 32% 31% 13%	739
August	1st to 10th	Day	10% 2 15% 38% 29% 6%	676
	11th to 20th	Day	13% 2 16% 32% 30% 7%	567
	21st to end	Day	9% 2 12% 30% 32% 15%	539
September	1st to 10th	Day	10% 2 13% 34% 32% 10%	490
	11th to 20th	Day	9% 3 18% 33% 28% 8%	466
	21st to end	Day	8% 9% 28% 29% 22% 3	300
October	1st to 10th	Day	10% 8% 29% 33% 16% 3	300
	11th to 20th	Day	15% 15% 36% 25% 9% 1	300
	21st to end	Day	27% 15% 33% 19% 5%	330
November	1st to 10th	Day	20% 15% 28% 29% 7% 1	300
	11th to 20th	Day	20% 19% 35% 18% 8% 1	300
	21st to end	Day	29% 15% 29% 17% 8% 2	300
December	1st to 10th	Day	17% 26% 33% 17% 5% 2	300
	11th to 20th	Day	26% 21% 27% 19% 6% 1	300
	21st to end	Day	28% 23% 34% 12% 2	330
January	1st to 10th	Night	21% 18% 33% 24% 5%	1000
	11th to 20th	Night	22% 19% 35% 20% 4	1000
	21st to end	Night	20% 18% 37% 21% 3	1100
February	1st to 10th	Night	22% 16% 37% 22% 3	1000
	11th to 20th	Night	23% 18% 37% 20% 2	914
	21st to end	Night	23% 17% 35% 22% 2	630
March	1st to 10th	Night	20% 17% 33% 27% 3	600
	11th to 20th	Night	24% 13% 32% 26% 5%	575
	21st to end	Night	23% 13% 37% 22% 5%	627
April	1st to 10th	Night	16% 15% 39% 26% 4	570
	11th to 20th	Night	18% 15% 34% 26% 7%	563
	21st to end	Night	22% 12% 37% 21% 7%	570
May	1st to 10th	Night	16% 8% 31% 35% 9%	570
	11th to 20th	Night	16% 7% 26% 32% 17% 1	561
	21st to end	Night	13% 5% 25% 36% 18% 2	617
June	1st to 10th	Night	10% 4 15% 39% 31% 2	570
	11th to 20th	Night	6% 2 21% 44% 26% 2	570
	21st to end	Night	2 1 19% 45% 30% 2	570
July	1st to 10th	Night	7% 1 10% 39% 35% 6%	555
	11th to 20th	Night	4 1 10% 40% 41% 5%	552
	21st to end	Night	6% 2 10% 39% 38% 5%	624
August	1st to 10th	Night	6% 1 8% 44% 35% 5%	567
	11th to 20th	Night	9% 2 12% 42% 33% 3	564
	21st to end	Night	7% 1 10% 39% 39% 5%	627
September	1st to 10th	Night	9% 2 14% 39% 33% 4	570
	11th to 20th	Night	11% 1 13% 41% 29% 5%	570
	21st to end	Night	10% 4 22% 37% 25% 3	649
October	1st to 10th	Night	8% 4 23% 36% 25% 3	760
	11th to 20th	Night	15% 10% 32% 33% 11% 1	760
	21st to end	Night	21% 11% 30% 30% 8%	836
November	1st to 10th	Night	15% 8% 34% 31% 10% 1	780
	11th to 20th	Night	18% 12% 31% 31% 8%	800
	21st to end	Night	22% 12% 29% 27% 10%	965
December	1st to 10th	Night	21% 15% 32% 26% 6%	1000
	11th to 20th	Night	24% 13% 30% 28% 5%	1000
	21st to end	Night	25% 19% 30% 22% 4	1100

Page generated at 2025-03-09 07:08:42. Version ac07

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