Cleburne State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cleburne State Park clear sky chart from 2005-11-06 to 2026-05-17.

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	10% 5% 2 5% 4 3 4 3 5% 7% 53%	132204
	Night	10% 5% 2 4 3 3 3 3 5% 6% 56%	130935
Transparency	Day	31% 4 9% 24% 23% 9%	135947
	Night	29% 3 8% 22% 25% 13%	135256
Seeing	Day	12% 7% 23% 29% 22% 6%	17061
	Night	13% 7% 29% 35% 15% 1	27036

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% 6% 2 4 3 3 3 2 3 6% 57%	5289
	11th to 20th	Day	7% 4 1 4 3 2 3 2 5% 5% 64%	5310
	21st to end	Day	21% 8% 2 5% 3 2 3 2 3 4 46%	5829
February	1st to 10th	Day	14% 6% 2 6% 4 3 2 3 4 5% 50%	2100
	11th to 20th	Day	14% 8% 2 6% 4 3 4 2 3 6% 48%	2049
	21st to end	Day	18% 5% 2 3 2 2 1 2 3 5% 56%	1730
March	1st to 10th	Day	13% 5% 2 5% 3 3 4 3 4 6% 51%	5018
	11th to 20th	Day	12% 4 2 5% 3 3 3 3 4 5% 56%	5090
	21st to end	Day	10% 6% 2 6% 4 4 3 3 5% 7% 50%	5583
April	1st to 10th	Day	11% 6% 2 6% 4 4 4 3 4 7% 48%	2310
	11th to 20th	Day	14% 7% 2 5% 3 3 4 3 5% 7% 47%	2333
	21st to end	Day	13% 5% 2 6% 4 4 4 4 5% 5% 48%	2730
May	1st to 10th	Day	15% 6% 3 6% 4 4 4 3 5% 7% 43%	5992
	11th to 20th	Day	12% 6% 2 6% 5% 4 4 3 5% 6% 47%	5941
	21st to end	Day	12% 7% 2 7% 4 4 5% 4 6% 8% 40%	6434
June	1st to 10th	Day	6% 3 2 5% 4 4 4 5% 6% 9% 53%	2600
	11th to 20th	Day	4 3 1 5% 4 4 4 4 6% 9% 55%	2600
	21st to end	Day	4 4 2 5% 4 4 4 4 6% 9% 55%	2600
July	1st to 10th	Day	9% 6% 2 7% 5% 6% 5% 4 6% 7% 43%	5900
	11th to 20th	Day	3 2 1 3 3 3 4 4 6% 10% 60%	5900
	21st to end	Day	4 3 1 5% 4 4 5% 5% 7% 10% 53%	6422
August	1st to 10th	Day	1 1 2 2 3 4 3 5% 7% 72%	4234
	11th to 20th	Day	4 2 1 3 2 3 4 3 5% 9% 65%	4115
	21st to end	Day	3 2 1 4 4 4 4 4 6% 8% 60%	4124
September	1st to 10th	Day	9% 4 2 5% 4 5% 4 4 4 6% 53%	2200
	11th to 20th	Day	9% 4 2 7% 5% 3 5% 4 6% 7% 49%	2200
	21st to end	Day	6% 3 2 4 3 3 3 4 5% 7% 60%	2200
October	1st to 10th	Day	6% 2 1 4 2 3 4 3 5% 6% 66%	2200
	11th to 20th	Day	9% 4 1 4 2 2 3 3 4 5% 63%	2000
	21st to end	Day	12% 4 1 5% 2 2 2 2 3 4 63%	2200
November	1st to 10th	Day	13% 6% 2 3 2 3 3 2 4 5% 57%	2058
	11th to 20th	Day	7% 3 2 4 4 4 3 3 4 6% 62%	1925
	21st to end	Day	14% 5% 2 6% 3 2 3 3 4 5% 53%	1890
December	1st to 10th	Day	16% 6% 2 4 3 3 3 3 4 5% 50%	3030
	11th to 20th	Day	16% 7% 2 6% 4 4 4 2 3 3 48%	3481
	21st to end	Day	16% 6% 2 5% 3 3 2 2 4 4 54%	4587
January	1st to 10th	Night	12% 4 2 4 2 2 3 2 4 6% 59%	7634
	11th to 20th	Night	7% 3 1 2 2 2 3 3 4 4 71%	7680
	21st to end	Night	22% 7% 3 5% 3 3 3 2 4 5% 43%	8402
February	1st to 10th	Night	13% 6% 2 5% 3 3 2 3 4 5% 53%	2535
	11th to 20th	Night	15% 7% 1 4 4 3 2 3 3 5% 52%	2458
	21st to end	Night	17% 5% 1 4 2 3 3 2 4 5% 54%	2076
March	1st to 10th	Night	13% 7% 2 6% 4 4 3 3 4 5% 49%	5042
	11th to 20th	Night	10% 5% 2 4 4 3 3 3 4 7% 55%	5090
	21st to end	Night	11% 6% 2 5% 3 4 3 3 4 6% 54%	5588
April	1st to 10th	Night	10% 5% 2 4 3 3 3 3 6% 7% 53%	2310
	11th to 20th	Night	12% 5% 2 5% 4 4 3 3 5% 6% 51%	2231
	21st to end	Night	12% 6% 2 4 3 3 2 3 5% 7% 53%	1890
May	1st to 10th	Night	17% 8% 2 6% 4 3 3 3 5% 7% 43%	4143
	11th to 20th	Night	8% 6% 3 7% 4 4 4 3 6% 7% 48%	4107
	21st to end	Night	11% 6% 2 4 3 4 4 4 6% 10% 47%	4443
June	1st to 10th	Night	4 3 1 4 3 4 4 3 7% 10% 58%	1800
	11th to 20th	Night	3 3 1 3 2 3 2 3 5% 9% 65%	1800
	21st to end	Night	2 3 2 4 3 3 3 4 7% 9% 60%	1800
July	1st to 10th	Night	8% 5% 2 5% 4 4 4 4 7% 10% 48%	4078
	11th to 20th	Night	2 1 1 2 2 2 3 3 5% 11% 66%	4077
	21st to end	Night	2 3 1 4 3 4 4 4 6% 8% 60%	4449
August	1st to 10th	Night	1 1 1 1 1 1 2 4 7% 81%	2926
	11th to 20th	Night	2 2 1 2 3 2 2 3 6% 11% 66%	2938
	21st to end	Night	2 2 1 3 3 3 3 3 6% 10% 64%	3777
September	1st to 10th	Night	8% 4 2 5% 3 4 4 3 6% 7% 54%	2200
	11th to 20th	Night	9% 5% 2 5% 3 4 3 3 5% 7% 54%	2200
	21st to end	Night	6% 3 1 3 3 3 3 3 5% 9% 61%	2200
October	1st to 10th	Night	5% 3 1 3 2 2 3 2 4 7% 68%	2200
	11th to 20th	Night	9% 3 1 3 2 2 2 2 5% 5% 65%	2380
	21st to end	Night	14% 4 1 3 1 2 3 2 3 4 62%	2640
November	1st to 10th	Night	10% 5% 2 4 3 2 2 2 3 4 63%	2460
	11th to 20th	Night	6% 4 1 4 3 3 3 3 4 6% 62%	2692
	21st to end	Night	16% 5% 2 5% 3 2 3 2 4 5% 54%	2730
December	1st to 10th	Night	16% 5% 2 5% 3 3 3 3 3 5% 53%	4380
	11th to 20th	Night	16% 7% 2 5% 3 3 3 2 3 5% 51%	4946
	21st to end	Night	14% 7% 2 4 2 2 2 2 3 4 57%	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	32% 2 6% 25% 29% 7%	5290
	11th to 20th	Day	25% 1 5% 25% 34% 11%	5310
	21st to end	Day	45% 2 4 17% 21% 12%	5829
February	1st to 10th	Day	38% 3 5% 17% 24% 13%	2100
	11th to 20th	Day	41% 2 6% 20% 21% 10%	2059
	21st to end	Day	35% 2 3 17% 26% 16%	1730
March	1st to 10th	Day	35% 3 6% 14% 22% 19%	5018
	11th to 20th	Day	32% 3 8% 15% 18% 25%	5090
	21st to end	Day	33% 4 10% 23% 20% 9%	5585
April	1st to 10th	Day	36% 4 10% 19% 20% 12%	2310
	11th to 20th	Day	39% 3 8% 19% 21% 10%	2333
	21st to end	Day	37% 4 7% 20% 24% 7%	2730
May	1st to 10th	Day	41% 4 10% 23% 19% 4	6030
	11th to 20th	Day	39% 4 8% 18% 25% 6%	5945
	21st to end	Day	41% 5% 11% 24% 14% 5%	6447
June	1st to 10th	Day	28% 6% 12% 31% 19% 4	2600
	11th to 20th	Day	25% 4 12% 31% 21% 6%	2600
	21st to end	Day	26% 5% 12% 27% 25% 6%	2600
July	1st to 10th	Day	39% 6% 15% 30% 10% 1	5836
	11th to 20th	Day	19% 5% 16% 36% 21% 3	5831
	21st to end	Day	24% 6% 16% 30% 22% 2	6240
August	1st to 10th	Day	12% 3 11% 32% 38% 5%	4220
	11th to 20th	Day	18% 4 14% 38% 24% 2	4154
	21st to end	Day	21% 7% 18% 33% 19% 2	4123
September	1st to 10th	Day	32% 4 9% 21% 23% 11%	2200
	11th to 20th	Day	34% 5% 10% 22% 21% 8%	2200
	21st to end	Day	24% 3 9% 24% 27% 14%	2200
October	1st to 10th	Day	13% 2 6% 15% 33% 31%	3590
	11th to 20th	Day	16% 2 5% 21% 35% 21%	3240
	21st to end	Day	22% 3 4 23% 35% 13%	3538
November	1st to 10th	Day	32% 3 7% 21% 26% 12%	2058
	11th to 20th	Day	25% 3 9% 22% 27% 15%	1925
	21st to end	Day	37% 2 4 21% 24% 12%	1890
December	1st to 10th	Day	38% 2 5% 24% 25% 6%	3030
	11th to 20th	Day	42% 3 5% 12% 27% 11%	3479
	21st to end	Day	36% 2 4 22% 25% 11%	4587
January	1st to 10th	Night	29% 2 6% 21% 33% 9%	7635
	11th to 20th	Night	19% 1 4 20% 36% 19%	7680
	21st to end	Night	46% 2 4 14% 21% 13%	8402
February	1st to 10th	Night	36% 2 7% 15% 24% 16%	2535
	11th to 20th	Night	37% 2 7% 18% 26% 11%	2458
	21st to end	Night	34% 3 6% 14% 23% 19%	2076
March	1st to 10th	Night	38% 4 5% 14% 21% 18%	5042
	11th to 20th	Night	31% 2 8% 17% 17% 24%	5090
	21st to end	Night	33% 3 7% 19% 27% 10%	5588
April	1st to 10th	Night	30% 4 9% 23% 19% 15%	2310
	11th to 20th	Night	33% 4 11% 18% 20% 14%	2231
	21st to end	Night	32% 4 11% 19% 27% 7%	1890
May	1st to 10th	Night	42% 4 8% 26% 15% 6%	4170
	11th to 20th	Night	36% 4 13% 18% 22% 8%	4108
	21st to end	Night	33% 5% 14% 29% 12% 8%	4452
June	1st to 10th	Night	22% 5% 15% 34% 19% 6%	1800
	11th to 20th	Night	18% 4 16% 33% 23% 7%	1800
	21st to end	Night	20% 7% 12% 28% 27% 6%	1800
July	1st to 10th	Night	32% 5% 15% 37% 10% 1	4035
	11th to 20th	Night	14% 4 16% 38% 24% 3	4026
	21st to end	Night	21% 6% 17% 31% 23% 2	4320
August	1st to 10th	Night	6% 2 9% 37% 40% 6%	2916
	11th to 20th	Night	15% 3 16% 39% 24% 3	2965
	21st to end	Night	16% 6% 20% 35% 20% 3	3777
September	1st to 10th	Night	29% 4 10% 23% 23% 11%	2200
	11th to 20th	Night	31% 4 12% 21% 22% 10%	2200
	21st to end	Night	23% 2 8% 25% 26% 17%	2200
October	1st to 10th	Night	12% 2 6% 15% 28% 38%	3590
	11th to 20th	Night	15% 2 5% 20% 32% 26%	3866
	21st to end	Night	23% 2 3 20% 37% 16%	4252
November	1st to 10th	Night	28% 2 7% 20% 28% 15%	2460
	11th to 20th	Night	24% 3 7% 22% 27% 17%	2692
	21st to end	Night	35% 2 6% 18% 27% 12%	2730
December	1st to 10th	Night	36% 2 5% 21% 25% 11%	4380
	11th to 20th	Night	38% 2 5% 12% 28% 15%	4947
	21st to end	Night	33% 2 5% 19% 26% 15%	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	21% 10% 39% 23% 7%	330
	11th to 20th	Day	19% 14% 32% 26% 7% 2	330
	21st to end	Day	22% 13% 37% 21% 6% 1	363
February	1st to 10th	Day	19% 15% 38% 21% 7%	330
	11th to 20th	Day	25% 18% 37% 16% 3	330
	21st to end	Day	23% 14% 38% 20% 5%	273
March	1st to 10th	Day	23% 18% 35% 19% 4 1	330
	11th to 20th	Day	21% 18% 37% 18% 5% 2	330
	21st to end	Day	14% 14% 44% 21% 6% 1	363
April	1st to 10th	Day	19% 15% 39% 22% 5% 1	330
	11th to 20th	Day	20% 16% 37% 22% 6%	371
	21st to end	Day	20% 13% 39% 19% 8% 1	750
May	1st to 10th	Day	14% 11% 39% 30% 6% 1	753
	11th to 20th	Day	16% 7% 31% 32% 12% 3	756
	21st to end	Day	15% 5% 30% 31% 16% 3	789
June	1st to 10th	Day	7% 2 18% 38% 26% 8%	730
	11th to 20th	Day	6% 3 21% 42% 25% 4	730
	21st to end	Day	4 1 12% 38% 37% 9%	730
July	1st to 10th	Day	8% 2 8% 35% 35% 12%	721
	11th to 20th	Day	2 7% 33% 44% 14%	718
	21st to end	Day	3 2 5% 31% 44% 14%	794
August	1st to 10th	Day	2 1 5% 33% 45% 14%	726
	11th to 20th	Day	8% 1 4 33% 43% 11%	685
	21st to end	Day	6% 1 5% 30% 37% 21%	473
September	1st to 10th	Day	8% 2 7% 26% 38% 19%	330
	11th to 20th	Day	3 1 5% 29% 46% 16%	330
	21st to end	Day	8% 2 8% 34% 32% 15%	330
October	1st to 10th	Day	3 2 17% 33% 34% 12%	330
	11th to 20th	Day	8% 6% 27% 35% 19% 5%	330
	21st to end	Day	23% 8% 24% 26% 15% 3	363
November	1st to 10th	Day	20% 6% 29% 30% 12% 3	330
	11th to 20th	Day	11% 8% 30% 32% 15% 3	330
	21st to end	Day	19% 12% 36% 22% 10% 1	330
December	1st to 10th	Day	16% 8% 34% 28% 11% 2	330
	11th to 20th	Day	20% 9% 34% 24% 10% 2	330
	21st to end	Day	18% 10% 35% 27% 9% 1	363
January	1st to 10th	Night	15% 9% 36% 33% 7%	1050
	11th to 20th	Night	17% 13% 30% 34% 6%	1050
	21st to end	Night	19% 11% 32% 31% 6%	1155
February	1st to 10th	Night	19% 11% 36% 29% 5%	855
	11th to 20th	Night	19% 13% 37% 28% 3	824
	21st to end	Night	23% 12% 41% 23% 2	692
March	1st to 10th	Night	18% 13% 38% 26% 5%	643
	11th to 20th	Night	17% 10% 40% 28% 5%	630
	21st to end	Night	13% 12% 43% 29% 4	693
April	1st to 10th	Night	14% 12% 44% 26% 5%	630
	11th to 20th	Night	15% 13% 41% 26% 4	623
	21st to end	Night	13% 11% 43% 25% 7%	630
May	1st to 10th	Night	13% 10% 40% 32% 5%	630
	11th to 20th	Night	12% 6% 37% 32% 12% 1	609
	21st to end	Night	11% 4 34% 37% 12% 2	650
June	1st to 10th	Night	5% 2 25% 44% 21% 3	600
	11th to 20th	Night	5% 1 27% 51% 14% 1	600
	21st to end	Night	4 1 21% 45% 28% 3	600
July	1st to 10th	Night	7% 1 11% 45% 32% 3	585
	11th to 20th	Night	3 12% 49% 32% 2	582
	21st to end	Night	2 1 8% 49% 37% 3	657
August	1st to 10th	Night	1 7% 49% 40% 3	597
	11th to 20th	Night	5% 1 7% 46% 37% 5%	594
	21st to end	Night	5% 1 6% 41% 43% 5%	660
September	1st to 10th	Night	10% 2 8% 42% 35% 3	600
	11th to 20th	Night	12% 2 7% 40% 38% 2	600
	21st to end	Night	7% 1 13% 43% 33% 3	600
October	1st to 10th	Night	6% 1 19% 45% 26% 3	600
	11th to 20th	Night	10% 4 26% 40% 18% 2	780
	21st to end	Night	17% 5% 29% 32% 15% 1	880
November	1st to 10th	Night	12% 4 29% 39% 15% 1	820
	11th to 20th	Night	8% 7% 35% 37% 12% 1	1012
	21st to end	Night	18% 9% 33% 28% 11% 1	1050
December	1st to 10th	Night	16% 8% 34% 35% 8%	1050
	11th to 20th	Night	21% 7% 32% 33% 7%	1050
	21st to end	Night	18% 9% 32% 33% 8%	1155

Page generated at 2026-05-14 00:58:53. Version ac07

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