Lake Livingston State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Livingston State Park clear sky chart from 2005-11-06 to 2025-09-19.

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% 6% 2 6% 5% 4 5% 4 6% 8% 42%	126115
	Night	13% 7% 2 5% 4 3 4 3 5% 7% 46%	123188
Transparency	Day	39% 6% 11% 19% 18% 7%	129751
	Night	37% 5% 11% 19% 19% 9%	127615
Seeing	Day	14% 8% 21% 26% 23% 9%	16132
	Night	16% 8% 24% 32% 19% 2	25883

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	19% 9% 3 6% 3 3 3 2 4 6% 42%	4077
	11th to 20th	Day	16% 6% 2 5% 3 3 3 2 3 5% 51%	4080
	21st to end	Day	27% 9% 3 6% 2 2 2 2 3 7% 36%	4488
February	1st to 10th	Day	20% 8% 3 7% 4 4 3 3 4 5% 37%	1830
	11th to 20th	Day	21% 10% 2 6% 4 4 4 2 4 5% 39%	1985
	21st to end	Day	21% 8% 3 6% 4 3 4 3 5% 5% 39%	1815
March	1st to 10th	Day	18% 9% 3 8% 5% 4 4 3 4 5% 37%	4936
	11th to 20th	Day	14% 6% 2 6% 4 3 4 3 4 7% 47%	4980
	21st to end	Day	16% 9% 3 6% 5% 4 4 3 5% 6% 39%	5462
April	1st to 10th	Day	16% 8% 3 7% 4 5% 4 4 6% 5% 39%	2200
	11th to 20th	Day	14% 7% 3 7% 4 4 5% 4 6% 6% 39%	2369
	21st to end	Day	11% 6% 2 7% 5% 5% 4 4 5% 7% 44%	2400
May	1st to 10th	Day	18% 7% 3 8% 6% 5% 5% 4 6% 7% 32%	5491
	11th to 20th	Day	12% 5% 2 7% 5% 4 5% 4 6% 8% 42%	5862
	21st to end	Day	10% 6% 3 7% 6% 6% 6% 5% 7% 10% 36%	6434
June	1st to 10th	Day	6% 5% 2 6% 6% 6% 6% 5% 8% 10% 41%	2600
	11th to 20th	Day	5% 4 2 5% 5% 5% 6% 6% 9% 11% 42%	2600
	21st to end	Day	6% 5% 2 6% 7% 8% 7% 7% 9% 9% 34%	2600
July	1st to 10th	Day	8% 5% 2 7% 6% 5% 6% 6% 9% 12% 34%	5900
	11th to 20th	Day	6% 5% 3 6% 5% 5% 7% 5% 10% 13% 35%	5900
	21st to end	Day	11% 7% 3 6% 5% 5% 5% 5% 6% 9% 37%	6422
August	1st to 10th	Day	2 2 1 3 3 3 3 3 6% 10% 64%	4234
	11th to 20th	Day	3 3 1 4 4 4 5% 5% 8% 13% 51%	3983
	21st to end	Day	8% 4 2 7% 5% 6% 7% 5% 7% 10% 39%	4312
September	1st to 10th	Day	7% 4 2 7% 5% 6% 6% 4 7% 9% 43%	2234
	11th to 20th	Day	13% 6% 2 6% 5% 5% 6% 4 6% 7% 39%	2178
	21st to end	Day	7% 4 1 5% 4 6% 4 3 6% 7% 52%	2090
October	1st to 10th	Day	6% 4 2 5% 4 3 4 3 5% 6% 60%	1945
	11th to 20th	Day	10% 4 1 5% 4 3 3 4 5% 6% 54%	1900
	21st to end	Day	14% 5% 2 4 3 2 3 2 5% 6% 54%	2090
November	1st to 10th	Day	10% 6% 2 7% 5% 5% 4 3 5% 7% 46%	1958
	11th to 20th	Day	11% 7% 2 5% 3 4 4 3 5% 5% 50%	2000
	21st to end	Day	15% 6% 3 6% 4 4 3 3 4 6% 45%	1941
December	1st to 10th	Day	20% 8% 2 5% 4 2 4 2 4 6% 43%	2940
	11th to 20th	Day	13% 9% 3 7% 4 4 4 4 5% 7% 42%	3391
	21st to end	Day	15% 8% 3 7% 4 3 3 3 4 5% 45%	4488
January	1st to 10th	Night	17% 7% 2 5% 3 3 3 3 5% 6% 47%	5888
	11th to 20th	Night	15% 7% 2 5% 3 3 3 2 3 4 53%	5900
	21st to end	Night	27% 10% 2 5% 3 3 3 2 3 6% 35%	6490
February	1st to 10th	Night	19% 10% 3 5% 4 3 3 3 5% 6% 39%	2585
	11th to 20th	Night	22% 9% 3 5% 3 3 3 3 4 6% 40%	2299
	21st to end	Night	21% 7% 2 6% 4 4 3 4 3 5% 41%	1815
March	1st to 10th	Night	21% 10% 3 5% 3 3 3 3 5% 6% 38%	4919
	11th to 20th	Night	15% 7% 3 6% 4 3 3 3 4 5% 47%	4980
	21st to end	Night	18% 10% 3 6% 4 3 4 3 4 4 41%	5467
April	1st to 10th	Night	15% 7% 2 6% 4 5% 5% 4 5% 6% 42%	2200
	11th to 20th	Night	14% 5% 3 6% 4 4 3 3 5% 7% 44%	1980
	21st to end	Night	15% 5% 3 7% 4 3 4 3 4 6% 46%	2000
May	1st to 10th	Night	20% 9% 3 8% 5% 4 5% 4 5% 9% 30%	4403
	11th to 20th	Night	13% 7% 3 7% 4 4 4 4 6% 8% 41%	4053
	21st to end	Night	11% 7% 2 7% 5% 4 6% 5% 8% 10% 34%	4443
June	1st to 10th	Night	7% 4 2 4 4 3 4 4 8% 9% 52%	1800
	11th to 20th	Night	4 3 2 3 4 3 5% 4 7% 11% 56%	1800
	21st to end	Night	5% 5% 2 6% 4 4 5% 5% 7% 12% 46%	1800
July	1st to 10th	Night	6% 5% 2 6% 5% 5% 5% 5% 9% 14% 38%	4078
	11th to 20th	Night	4 4 1 5% 4 5% 5% 4 8% 12% 48%	4077
	21st to end	Night	8% 6% 3 6% 5% 4 5% 4 6% 9% 44%	4449
August	1st to 10th	Night	1 2 1 2 2 3 3 2 6% 10% 70%	2926
	11th to 20th	Night	2 2 1 2 2 3 4 3 7% 13% 61%	3069
	21st to end	Night	6% 3 2 5% 5% 5% 6% 5% 8% 11% 45%	3586
September	1st to 10th	Night	5% 5% 2 6% 5% 4 6% 3 6% 10% 47%	2160
	11th to 20th	Night	11% 6% 2 6% 4 4 5% 4 6% 8% 44%	2178
	21st to end	Night	8% 4 1 5% 4 3 4 3 6% 7% 55%	2090
October	1st to 10th	Night	4 3 1 4 4 3 4 3 5% 8% 60%	2214
	11th to 20th	Night	11% 4 1 3 3 2 3 2 4 6% 61%	2280
	21st to end	Night	12% 5% 1 4 3 2 3 2 4 5% 58%	2508
November	1st to 10th	Night	12% 5% 2 4 4 4 4 3 5% 7% 51%	2340
	11th to 20th	Night	11% 4 2 6% 3 3 3 3 5% 6% 53%	2400
	21st to end	Night	15% 7% 2 6% 3 3 4 3 5% 6% 46%	2455
December	1st to 10th	Night	19% 9% 3 7% 4 4 3 2 5% 5% 39%	4250
	11th to 20th	Night	17% 10% 2 6% 3 3 4 3 4 5% 43%	4816
	21st to end	Night	15% 7% 2 5% 3 3 3 3 3 4 51%	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	45% 4 4 22% 20% 6%	4078
	11th to 20th	Day	38% 3 3 17% 29% 10%	4080
	21st to end	Day	51% 2 3 14% 16% 13%	4488
February	1st to 10th	Day	50% 3 5% 13% 18% 10%	1830
	11th to 20th	Day	50% 4 5% 15% 15% 10%	1995
	21st to end	Day	49% 4 7% 15% 16% 10%	1815
March	1st to 10th	Day	50% 4 6% 11% 19% 11%	4936
	11th to 20th	Day	39% 4 6% 13% 20% 19%	4980
	21st to end	Day	46% 5% 7% 19% 17% 5%	5464
April	1st to 10th	Day	46% 6% 6% 17% 17% 9%	2200
	11th to 20th	Day	44% 5% 9% 14% 17% 10%	2369
	21st to end	Day	39% 6% 9% 19% 22% 5%	2400
May	1st to 10th	Day	50% 6% 9% 21% 10% 3	5526
	11th to 20th	Day	39% 6% 15% 17% 21% 2	5866
	21st to end	Day	41% 8% 11% 26% 12% 2	6447
June	1st to 10th	Day	37% 10% 15% 22% 15% 1	2600
	11th to 20th	Day	32% 10% 14% 25% 15% 2	2600
	21st to end	Day	42% 12% 16% 20% 11% 1	2600
July	1st to 10th	Day	38% 10% 27% 21% 3	5836
	11th to 20th	Day	36% 9% 23% 25% 6%	5831
	21st to end	Day	41% 9% 16% 25% 9% 1	6240
August	1st to 10th	Day	16% 6% 14% 37% 26% 1	4220
	11th to 20th	Day	22% 8% 28% 33% 8% 1	4022
	21st to end	Day	38% 10% 17% 19% 15% 1	4311
September	1st to 10th	Day	37% 10% 13% 18% 16% 7%	2234
	11th to 20th	Day	43% 8% 12% 17% 16% 5%	2178
	21st to end	Day	31% 7% 10% 21% 17% 12%	2090
October	1st to 10th	Day	18% 4 6% 13% 21% 38%	3231
	11th to 20th	Day	21% 3 4 19% 35% 19%	3140
	21st to end	Day	26% 4 4 13% 39% 14%	3428
November	1st to 10th	Day	37% 6% 8% 18% 20% 10%	1958
	11th to 20th	Day	36% 5% 6% 17% 22% 14%	2000
	21st to end	Day	42% 4 6% 19% 20% 10%	1941
December	1st to 10th	Day	44% 3 6% 17% 25% 5%	2940
	11th to 20th	Day	42% 5% 7% 14% 22% 10%	3389
	21st to end	Day	42% 4 4 14% 28% 8%	4488
January	1st to 10th	Night	38% 5% 5% 23% 22% 7%	5888
	11th to 20th	Night	37% 2 4 17% 30% 9%	5900
	21st to end	Night	53% 3 3 13% 16% 12%	6490
February	1st to 10th	Night	47% 3 5% 13% 17% 13%	2585
	11th to 20th	Night	48% 3 6% 14% 18% 11%	2299
	21st to end	Night	47% 4 6% 13% 16% 14%	1815
March	1st to 10th	Night	49% 4 5% 12% 20% 10%	4919
	11th to 20th	Night	41% 5% 6% 15% 16% 17%	4980
	21st to end	Night	48% 5% 6% 14% 20% 7%	5467
April	1st to 10th	Night	43% 6% 9% 16% 16% 11%	2200
	11th to 20th	Night	40% 4 9% 18% 17% 12%	1980
	21st to end	Night	40% 5% 8% 19% 22% 6%	2000
May	1st to 10th	Night	52% 7% 9% 19% 10% 3	4433
	11th to 20th	Night	42% 6% 11% 19% 20% 2	4054
	21st to end	Night	42% 8% 16% 24% 9% 1	4452
June	1st to 10th	Night	26% 9% 18% 30% 17% 1	1800
	11th to 20th	Night	22% 8% 18% 31% 17% 4	1800
	21st to end	Night	29% 9% 22% 27% 12% 1	1800
July	1st to 10th	Night	34% 9% 33% 22% 3	4035
	11th to 20th	Night	27% 9% 28% 30% 6%	4026
	21st to end	Night	36% 9% 19% 28% 8%	4320
August	1st to 10th	Night	11% 5% 19% 39% 25% 1	2916
	11th to 20th	Night	15% 7% 33% 36% 9% 1	3096
	21st to end	Night	31% 12% 19% 24% 11% 2	3586
September	1st to 10th	Night	31% 8% 20% 20% 14% 7%	2160
	11th to 20th	Night	37% 7% 14% 21% 15% 6%	2178
	21st to end	Night	28% 6% 12% 21% 20% 12%	2090
October	1st to 10th	Night	15% 4 6% 17% 18% 39%	3695
	11th to 20th	Night	16% 3 4 23% 32% 23%	3779
	21st to end	Night	24% 3 5% 13% 40% 15%	4120
November	1st to 10th	Night	33% 6% 9% 19% 21% 11%	2340
	11th to 20th	Night	34% 4 8% 17% 23% 13%	2400
	21st to end	Night	39% 4 8% 18% 20% 11%	2455
December	1st to 10th	Night	49% 3 5% 17% 21% 6%	4250
	11th to 20th	Night	44% 3 7% 10% 22% 13%	4817
	21st to end	Night	38% 5% 5% 15% 29% 9%	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	27% 15% 36% 16% 5% 1	300
	11th to 20th	Day	26% 15% 34% 19% 5% 1	300
	21st to end	Day	27% 18% 34% 18% 4	330
February	1st to 10th	Day	26% 15% 34% 20% 3	300
	11th to 20th	Day	30% 18% 33% 17% 2	300
	21st to end	Day	30% 22% 35% 10% 4	249
March	1st to 10th	Day	27% 20% 30% 18% 5%	300
	11th to 20th	Day	17% 28% 38% 13% 3	300
	21st to end	Day	23% 15% 41% 16% 5% 1	330
April	1st to 10th	Day	24% 19% 34% 21% 2	300
	11th to 20th	Day	25% 16% 25% 25% 9%	487
	21st to end	Day	17% 15% 33% 24% 9% 2	500
May	1st to 10th	Day	17% 12% 34% 26% 10%	537
	11th to 20th	Day	12% 11% 29% 31% 14% 2	725
	21st to end	Day	9% 7% 30% 34% 18% 2	789
June	1st to 10th	Day	6% 4 17% 35% 27% 10%	730
	11th to 20th	Day	7% 2 17% 38% 28% 8%	730
	21st to end	Day	7% 3 13% 27% 36% 15%	730
July	1st to 10th	Day	8% 3 9% 28% 34% 19%	721
	11th to 20th	Day	5% 1 4 29% 43% 18%	718
	21st to end	Day	7% 3 5% 24% 41% 20%	794
August	1st to 10th	Day	4 1 5% 22% 47% 22%	726
	11th to 20th	Day	4 2 18% 51% 24%	605
	21st to end	Day	10% 2 6% 20% 36% 26%	583
September	1st to 10th	Day	6% 2 8% 27% 41% 16%	364
	11th to 20th	Day	10% 4 11% 23% 37% 15%	324
	21st to end	Day	11% 2 10% 31% 35% 12%	300
October	1st to 10th	Day	5% 3 21% 39% 27% 6%	300
	11th to 20th	Day	11% 4 23% 37% 17% 9%	300
	21st to end	Day	21% 8% 25% 25% 16% 5%	330
November	1st to 10th	Day	15% 5% 26% 35% 17% 3	300
	11th to 20th	Day	14% 11% 31% 35% 8% 1	300
	21st to end	Day	18% 20% 30% 20% 10% 2	300
December	1st to 10th	Day	18% 11% 36% 20% 10% 4	300
	11th to 20th	Day	21% 16% 36% 22% 4 1	300
	21st to end	Day	24% 14% 34% 22% 5% 1	330
January	1st to 10th	Night	24% 11% 31% 29% 6%	1000
	11th to 20th	Night	24% 14% 29% 26% 7%	1000
	21st to end	Night	25% 12% 29% 29% 4	1100
February	1st to 10th	Night	26% 14% 33% 25% 3	985
	11th to 20th	Night	29% 11% 32% 24% 4	745
	21st to end	Night	24% 15% 36% 24% 2	495
March	1st to 10th	Night	26% 12% 34% 24% 5%	600
	11th to 20th	Night	19% 14% 35% 27% 5%	600
	21st to end	Night	17% 12% 38% 26% 7%	660
April	1st to 10th	Night	20% 10% 39% 26% 6%	600
	11th to 20th	Night	19% 12% 32% 29% 8%	593
	21st to end	Night	20% 9% 33% 29% 9%	600
May	1st to 10th	Night	16% 11% 35% 31% 7%	600
	11th to 20th	Night	16% 7% 27% 34% 15% 1	591
	21st to end	Night	9% 5% 28% 36% 19% 2	650
June	1st to 10th	Night	6% 2 16% 40% 33% 4	600
	11th to 20th	Night	5% 3 17% 45% 27% 3	600
	21st to end	Night	7% 3 11% 38% 37% 6%	600
July	1st to 10th	Night	5% 1 7% 41% 37% 8%	585
	11th to 20th	Night	4 1 7% 39% 43% 5%	582
	21st to end	Night	5% 1 6% 40% 42% 6%	657
August	1st to 10th	Night	2 6% 41% 45% 5%	597
	11th to 20th	Night	5% 1 2 39% 46% 6%	594
	21st to end	Night	7% 1 6% 30% 46% 10%	660
September	1st to 10th	Night	6% 2 10% 32% 44% 8%	600
	11th to 20th	Night	13% 2 6% 29% 44% 7%	594
	21st to end	Night	9% 3 9% 36% 38% 6%	570
October	1st to 10th	Night	5% 2 13% 38% 37% 5%	694
	11th to 20th	Night	12% 4 22% 41% 19% 2	760
	21st to end	Night	14% 6% 27% 31% 19% 2	836
November	1st to 10th	Night	13% 6% 23% 35% 21% 2	780
	11th to 20th	Night	13% 10% 26% 38% 13%	800
	21st to end	Night	19% 11% 29% 28% 13% 1	855
December	1st to 10th	Night	23% 10% 27% 29% 11% 1	1000
	11th to 20th	Night	25% 11% 29% 29% 6%	1000
	21st to end	Night	24% 12% 28% 30% 7%	1100

Page generated at 2025-09-16 00:49:10. Version ac07

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