LoneStar Gazer Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the LoneStar Gazer Observatory clear sky chart from 2005-11-06 to 2024-12-24.

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 5% 4 4 4 4 5% 7% 47%	101502
	Night	13% 6% 2 5% 3 3 3 3 5% 7% 51%	98715
Transparency	Day	34% 6% 10% 21% 20% 9%	105309
	Night	32% 5% 11% 20% 20% 11%	103034
Seeing	Day	14% 9% 23% 30% 21% 5%	15029
	Night	16% 8% 27% 34% 14% 1	24999

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% 9% 2 5% 3 3 3 2 4 5% 51%	2847
	11th to 20th	Day	17% 5% 1 2 3 2 2 2 4 5% 56%	2850
	21st to end	Day	18% 8% 3 7% 3 3 2 2 3 7% 44%	3295
February	1st to 10th	Day	20% 7% 2 5% 3 3 3 2 4 4 46%	1900
	11th to 20th	Day	17% 8% 3 4 3 3 3 3 5% 5% 46%	1849
	21st to end	Day	19% 6% 2 4 3 2 3 3 4 5% 49%	1570
March	1st to 10th	Day	16% 8% 3 7% 4 4 4 3 4 5% 42%	3422
	11th to 20th	Day	20% 10% 3 8% 5% 4 4 4 5% 5% 33%	3480
	21st to end	Day	13% 8% 2 6% 4 4 4 4 5% 6% 44%	3814
April	1st to 10th	Day	15% 8% 2 6% 4 4 4 3 5% 6% 42%	2090
	11th to 20th	Day	17% 8% 3 6% 4 3 4 3 4 6% 43%	2066
	21st to end	Day	15% 6% 2 5% 5% 4 4 3 5% 6% 46%	2432
May	1st to 10th	Day	23% 8% 3 6% 5% 4 4 5% 6% 7% 30%	4082
	11th to 20th	Day	16% 6% 2 6% 4 4 4 3 5% 7% 44%	4082
	21st to end	Day	12% 6% 3 7% 5% 5% 7% 6% 8% 10% 34%	4477
June	1st to 10th	Day	5% 4 2 6% 5% 4 5% 4 7% 8% 50%	2470
	11th to 20th	Day	8% 3 1 5% 4 4 5% 5% 7% 9% 48%	2470
	21st to end	Day	7% 6% 2 5% 5% 6% 5% 5% 8% 9% 41%	2470
July	1st to 10th	Day	6% 4 2 5% 5% 4 5% 4 6% 9% 50%	4120
	11th to 20th	Day	4 3 1 5% 3 4 4 4 7% 11% 52%	4120
	21st to end	Day	10% 6% 3 6% 5% 4 6% 5% 6% 10% 39%	4465
August	1st to 10th	Day	1 1 1 2 2 3 3 3 5% 8% 72%	4104
	11th to 20th	Day	3 2 1 3 3 3 4 4 6% 10% 60%	3800
	21st to end	Day	4 3 1 5% 4 5% 5% 5% 7% 12% 49%	3988
September	1st to 10th	Day	8% 5% 2 6% 5% 4 5% 4 6% 8% 45%	2090
	11th to 20th	Day	12% 5% 2 7% 4 4 5% 4 7% 7% 43%	2090
	21st to end	Day	7% 4 2 5% 4 4 6% 3 6% 8% 53%	2090
October	1st to 10th	Day	6% 5% 1 4 3 4 4 3 5% 7% 59%	2090
	11th to 20th	Day	12% 4 2 5% 4 3 3 3 4 5% 55%	1938
	21st to end	Day	11% 5% 1 4 3 3 3 2 4 5% 60%	2090
November	1st to 10th	Day	15% 7% 2 5% 3 3 4 4 5% 6% 47%	1958
	11th to 20th	Day	10% 6% 2 6% 4 4 3 3 4 6% 53%	1880
	21st to end	Day	16% 7% 2 5% 3 3 4 3 4 5% 47%	1800
December	1st to 10th	Day	15% 8% 3 5% 3 3 3 3 5% 5% 48%	1800
	11th to 20th	Day	17% 7% 2 6% 4 3 4 3 5% 4 45%	2251
	21st to end	Day	16% 6% 2 4 2 2 3 3 3 4 54%	3162
January	1st to 10th	Night	19% 6% 2 3 2 2 2 2 3 5% 54%	4108
	11th to 20th	Night	14% 4 1 3 2 2 2 2 2 4 65%	4120
	21st to end	Night	19% 7% 3 7% 4 3 3 3 3 6% 43%	4400
February	1st to 10th	Night	20% 7% 2 5% 2 3 3 2 3 6% 48%	2280
	11th to 20th	Night	20% 6% 2 5% 3 3 2 2 4 5% 49%	2218
	21st to end	Night	20% 6% 2 4 3 3 3 2 4 5% 47%	1884
March	1st to 10th	Night	17% 8% 2 6% 4 4 4 3 5% 6% 41%	3430
	11th to 20th	Night	22% 9% 2 7% 5% 4 4 4 5% 5% 34%	3480
	21st to end	Night	14% 8% 3 7% 5% 3 4 3 5% 5% 43%	3817
April	1st to 10th	Night	14% 7% 2 5% 3 4 4 3 6% 7% 47%	2090
	11th to 20th	Night	19% 6% 2 5% 3 3 3 3 5% 5% 44%	2063
	21st to end	Night	16% 6% 3 5% 3 3 4 3 3 6% 47%	1743
May	1st to 10th	Night	25% 9% 2 6% 3 3 3 3 5% 5% 36%	2823
	11th to 20th	Night	11% 6% 3 5% 3 3 4 3 5% 6% 50%	2823
	21st to end	Night	13% 6% 2 5% 3 4 5% 4 6% 8% 42%	3090
June	1st to 10th	Night	5% 3 1 3 3 3 3 3 6% 11% 59%	1710
	11th to 20th	Night	5% 2 2 4 3 3 4 4 5% 10% 57%	1710
	21st to end	Night	7% 5% 1 4 4 3 4 3 6% 10% 54%	1710
July	1st to 10th	Night	5% 3 1 4 3 3 4 4 6% 10% 56%	2850
	11th to 20th	Night	3 3 1 4 4 3 3 3 7% 11% 57%	2850
	21st to end	Night	9% 7% 2 6% 3 4 4 5% 6% 10% 43%	3098
August	1st to 10th	Night	1 1 2 2 2 2 2 5% 8% 77%	2836
	11th to 20th	Night	3 2 1 3 2 3 3 4 6% 11% 61%	3022
	21st to end	Night	4 3 1 4 3 4 4 4 6% 11% 56%	3673
September	1st to 10th	Night	8% 5% 2 5% 4 4 5% 3 5% 8% 51%	2090
	11th to 20th	Night	10% 7% 2 6% 5% 4 4 3 6% 8% 46%	2090
	21st to end	Night	8% 4 1 4 3 4 4 3 6% 8% 55%	2090
October	1st to 10th	Night	7% 3 1 4 3 3 3 3 4 6% 63%	2090
	11th to 20th	Night	12% 5% 1 4 3 3 3 3 4 5% 56%	2220
	21st to end	Night	14% 4 2 3 3 2 3 3 3 4 60%	2508
November	1st to 10th	Night	15% 6% 2 5% 3 3 3 2 4 6% 52%	2340
	11th to 20th	Night	10% 5% 1 4 3 3 3 2 5% 6% 57%	2515
	21st to end	Night	17% 5% 2 5% 3 3 4 2 4 6% 48%	2600
December	1st to 10th	Night	15% 6% 2 5% 3 3 3 2 4 5% 51%	2600
	11th to 20th	Night	16% 9% 3 5% 3 3 3 3 4 5% 47%	3166
	21st to end	Night	19% 6% 2 3 2 2 2 2 3 4 54%	4578

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	36% 3 5% 18% 25% 14%	2848
	11th to 20th	Day	32% 3 7% 15% 30% 14%	2850
	21st to end	Day	42% 3 6% 10% 28% 12%	3295
February	1st to 10th	Day	42% 4 6% 13% 21% 14%	1900
	11th to 20th	Day	41% 3 8% 16% 20% 12%	1859
	21st to end	Day	40% 3 6% 18% 19% 15%	1570
March	1st to 10th	Day	43% 4 8% 13% 21% 11%	3422
	11th to 20th	Day	51% 7% 8% 9% 16% 8%	3480
	21st to end	Day	38% 6% 10% 14% 23% 9%	3814
April	1st to 10th	Day	42% 5% 8% 17% 15% 13%	2090
	11th to 20th	Day	43% 6% 7% 15% 19% 11%	2066
	21st to end	Day	39% 6% 6% 20% 20% 9%	2432
May	1st to 10th	Day	52% 7% 10% 14% 13% 5%	4120
	11th to 20th	Day	40% 6% 9% 17% 23% 5%	4086
	21st to end	Day	39% 11% 13% 25% 10% 2	4489
June	1st to 10th	Day	29% 8% 13% 27% 19% 4	2470
	11th to 20th	Day	30% 7% 13% 26% 17% 6%	2470
	21st to end	Day	35% 9% 12% 23% 18% 3	2470
July	1st to 10th	Day	30% 7% 17% 38% 8% 1	4056
	11th to 20th	Day	25% 6% 17% 33% 17% 2	4051
	21st to end	Day	37% 8% 18% 28% 9% 1	4325
August	1st to 10th	Day	12% 4 11% 39% 32% 1	4090
	11th to 20th	Day	20% 5% 21% 39% 13% 3	3838
	21st to end	Day	26% 9% 20% 25% 18% 2	3987
September	1st to 10th	Day	35% 7% 10% 22% 16% 10%	2090
	11th to 20th	Day	38% 8% 11% 19% 18% 6%	2090
	21st to end	Day	29% 7% 9% 21% 19% 14%	2090
October	1st to 10th	Day	16% 3 6% 12% 25% 38%	3480
	11th to 20th	Day	21% 3 8% 19% 29% 20%	3204
	21st to end	Day	25% 4 4 20% 33% 14%	3428
November	1st to 10th	Day	37% 6% 9% 17% 21% 11%	1958
	11th to 20th	Day	34% 4 7% 18% 21% 16%	1880
	21st to end	Day	40% 4 6% 17% 20% 14%	1800
December	1st to 10th	Day	39% 4 9% 19% 22% 9%	1800
	11th to 20th	Day	41% 6% 7% 12% 22% 13%	2249
	21st to end	Day	35% 4 5% 14% 28% 14%	3162
January	1st to 10th	Night	34% 3 6% 15% 24% 17%	4108
	11th to 20th	Night	27% 2 5% 16% 30% 20%	4120
	21st to end	Night	44% 3 5% 12% 25% 11%	4400
February	1st to 10th	Night	40% 4 6% 13% 20% 17%	2280
	11th to 20th	Night	39% 4 7% 16% 20% 15%	2218
	21st to end	Night	41% 4 6% 14% 18% 17%	1884
March	1st to 10th	Night	43% 6% 9% 14% 19% 10%	3430
	11th to 20th	Night	51% 6% 9% 10% 14% 9%	3480
	21st to end	Night	42% 6% 9% 15% 20% 9%	3817
April	1st to 10th	Night	37% 6% 8% 17% 17% 15%	2090
	11th to 20th	Night	41% 5% 10% 14% 16% 15%	2063
	21st to end	Night	40% 4 9% 19% 19% 9%	1743
May	1st to 10th	Night	49% 6% 9% 16% 14% 6%	2850
	11th to 20th	Night	33% 8% 10% 25% 17% 8%	2824
	21st to end	Night	36% 9% 13% 28% 9% 4	3099
June	1st to 10th	Night	21% 7% 17% 29% 23% 3	1710
	11th to 20th	Night	22% 6% 16% 29% 21% 6%	1710
	21st to end	Night	27% 7% 16% 29% 18% 3	1710
July	1st to 10th	Night	23% 8% 26% 36% 7% 1	2805
	11th to 20th	Night	21% 7% 19% 36% 16% 1	2796
	21st to end	Night	37% 6% 22% 28% 8%	2999
August	1st to 10th	Night	8% 4 14% 43% 29% 1	2826
	11th to 20th	Night	18% 5% 29% 33% 12% 2	3049
	21st to end	Night	23% 10% 21% 27% 17% 2	3673
September	1st to 10th	Night	30% 7% 13% 24% 17% 8%	2090
	11th to 20th	Night	35% 7% 14% 22% 15% 7%	2090
	21st to end	Night	27% 6% 13% 22% 18% 13%	2090
October	1st to 10th	Night	15% 4 6% 15% 20% 41%	3480
	11th to 20th	Night	20% 3 9% 16% 31% 21%	3680
	21st to end	Night	25% 3 5% 19% 32% 16%	4120
November	1st to 10th	Night	35% 5% 8% 17% 22% 13%	2340
	11th to 20th	Night	30% 5% 8% 20% 22% 17%	2515
	21st to end	Night	39% 4 7% 17% 18% 15%	2600
December	1st to 10th	Night	37% 4 8% 20% 20% 11%	2600
	11th to 20th	Night	41% 4 6% 11% 22% 17%	3167
	21st to end	Night	36% 3 5% 14% 29% 13%	4578

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	19% 17% 34% 24% 3 1	270
	11th to 20th	Day	24% 16% 29% 24% 6% 1	270
	21st to end	Day	21% 20% 32% 22% 6%	297
February	1st to 10th	Day	29% 17% 31% 16% 7%	270
	11th to 20th	Day	26% 21% 35% 16% 1 1	270
	21st to end	Day	27% 25% 33% 14% 1	225
March	1st to 10th	Day	23% 22% 35% 17% 3	270
	11th to 20th	Day	21% 24% 33% 16% 6%	270
	21st to end	Day	18% 22% 39% 17% 5%	297
April	1st to 10th	Day	23% 20% 39% 14% 4	270
	11th to 20th	Day	20% 23% 32% 18% 7%	264
	21st to end	Day	19% 15% 38% 20% 7%	612
May	1st to 10th	Day	17% 13% 37% 25% 7%	653
	11th to 20th	Day	20% 7% 27% 32% 11% 2	675
	21st to end	Day	18% 7% 28% 33% 13% 2	734
June	1st to 10th	Day	7% 3 18% 39% 27% 6%	680
	11th to 20th	Day	9% 2 18% 46% 20% 5%	680
	21st to end	Day	7% 2 15% 36% 31% 9%	680
July	1st to 10th	Day	7% 2 10% 42% 30% 10%	671
	11th to 20th	Day	4 8% 39% 42% 7%	668
	21st to end	Day	6% 1 6% 37% 43% 8%	739
August	1st to 10th	Day	2 1 8% 36% 43% 11%	676
	11th to 20th	Day	6% 6% 39% 40% 10%	527
	21st to end	Day	6% 9% 30% 36% 18%	425
September	1st to 10th	Day	10% 8% 26% 41% 15%	300
	11th to 20th	Day	10% 9% 28% 43% 10%	300
	21st to end	Day	10% 2 8% 35% 35% 11%	300
October	1st to 10th	Day	4 3 18% 38% 30% 7%	300
	11th to 20th	Day	11% 6% 28% 31% 21% 4	300
	21st to end	Day	19% 15% 23% 25% 15% 3	330
November	1st to 10th	Day	22% 7% 27% 30% 9% 4	300
	11th to 20th	Day	17% 13% 30% 24% 14% 2	300
	21st to end	Day	22% 18% 33% 16% 10% 1	300
December	1st to 10th	Day	18% 12% 36% 21% 10% 3	300
	11th to 20th	Day	20% 16% 35% 21% 7%	300
	21st to end	Day	20% 13% 37% 19% 9% 1	306
January	1st to 10th	Night	20% 11% 30% 31% 8% 1	950
	11th to 20th	Night	21% 11% 30% 30% 7%	950
	21st to end	Night	20% 13% 31% 30% 6%	965
February	1st to 10th	Night	25% 12% 31% 26% 5%	760
	11th to 20th	Night	25% 13% 35% 25% 2	744
	21st to end	Night	26% 14% 40% 19% 1	628
March	1st to 10th	Night	24% 13% 36% 24% 3	581
	11th to 20th	Night	22% 11% 34% 29% 4	570
	21st to end	Night	17% 15% 41% 25% 3	627
April	1st to 10th	Night	16% 13% 40% 28% 2	570
	11th to 20th	Night	22% 13% 39% 22% 4	563
	21st to end	Night	18% 11% 42% 21% 8%	570
May	1st to 10th	Night	17% 11% 38% 28% 5%	570
	11th to 20th	Night	14% 7% 34% 33% 11% 1	561
	21st to end	Night	14% 6% 34% 33% 13%	617
June	1st to 10th	Night	6% 2 24% 45% 21% 2	570
	11th to 20th	Night	5% 2 34% 46% 12% 1	570
	21st to end	Night	7% 2 19% 45% 24% 2	570
July	1st to 10th	Night	7% 1 17% 43% 28% 4	555
	11th to 20th	Night	4 14% 53% 27% 2	552
	21st to end	Night	5% 13% 50% 28% 3	624
August	1st to 10th	Night	1 9% 57% 28% 4	567
	11th to 20th	Night	6% 1 10% 51% 29% 4	564
	21st to end	Night	7% 7% 48% 33% 5%	627
September	1st to 10th	Night	10% 1 11% 41% 32% 6%	570
	11th to 20th	Night	12% 2 10% 41% 32% 4	570
	21st to end	Night	12% 1 13% 36% 36% 3	570
October	1st to 10th	Night	7% 2 15% 45% 27% 4	570
	11th to 20th	Night	14% 4 24% 37% 19% 2	700
	21st to end	Night	16% 10% 25% 29% 19% 1	836
November	1st to 10th	Night	16% 6% 23% 38% 16% 1	780
	11th to 20th	Night	14% 8% 29% 34% 14% 1	915
	21st to end	Night	21% 10% 29% 28% 12% 1	1000
December	1st to 10th	Night	20% 8% 31% 31% 10% 1	1000
	11th to 20th	Night	24% 10% 29% 31% 6%	1000
	21st to end	Night	22% 10% 28% 32% 8%	1063

Page generated at 2024-12-21 03:13:51. Version ac07

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