Cosmic Obsession - Kerrville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cosmic Obsession - Kerrville 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	9% 6% 2 5% 4 4 4 3 5% 7% 51%	132355
	Night	9% 6% 2 5% 3 3 3 3 5% 7% 54%	130830
Transparency	Day	33% 5% 9% 21% 20% 12%	136199
	Night	31% 4 10% 20% 21% 15%	135050
Seeing	Day	11% 8% 25% 31% 20% 5%	16768
	Night	11% 8% 31% 36% 13% 1	26806

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	9% 4 3 5% 3 3 3 3 4 5% 59%	5289
	11th to 20th	Day	10% 7% 2 4 3 2 2 2 5% 5% 59%	5467
	21st to end	Day	17% 7% 2 5% 3 4 4 3 4 6% 46%	6468
February	1st to 10th	Day	11% 7% 2 6% 3 4 3 3 5% 5% 52%	2100
	11th to 20th	Day	11% 7% 2 6% 4 3 3 4 5% 5% 50%	2049
	21st to end	Day	12% 5% 2 5% 2 3 3 3 5% 6% 55%	1730
March	1st to 10th	Day	9% 6% 2 5% 3 3 3 3 4 6% 56%	4769
	11th to 20th	Day	11% 7% 2 6% 3 3 3 2 3 5% 55%	5090
	21st to end	Day	9% 6% 2 6% 3 4 3 3 5% 6% 52%	5583
April	1st to 10th	Day	11% 7% 2 6% 4 4 4 3 5% 7% 47%	2310
	11th to 20th	Day	13% 6% 2 7% 4 4 3 3 5% 6% 47%	2473
	21st to end	Day	11% 7% 2 7% 5% 4 3 3 5% 6% 48%	2557
May	1st to 10th	Day	13% 7% 3 7% 4 4 4 4 5% 7% 42%	5992
	11th to 20th	Day	8% 6% 2 6% 4 4 4 3 6% 8% 48%	5941
	21st to end	Day	11% 7% 2 6% 5% 5% 5% 4 6% 9% 39%	6434
June	1st to 10th	Day	4 4 2 5% 4 4 5% 4 6% 9% 53%	2600
	11th to 20th	Day	6% 3 2 6% 4 4 4 4 7% 10% 51%	2600
	21st to end	Day	5% 5% 2 5% 5% 6% 6% 5% 7% 9% 44%	2600
July	1st to 10th	Day	13% 7% 3 7% 4 5% 5% 4 6% 9% 37%	5900
	11th to 20th	Day	4 4 2 6% 5% 5% 6% 4 6% 8% 49%	5900
	21st to end	Day	6% 4 2 5% 4 4 5% 4 7% 10% 49%	6422
August	1st to 10th	Day	1 2 1 3 3 3 4 3 5% 8% 68%	3911
	11th to 20th	Day	4 2 1 4 3 3 4 3 6% 9% 61%	3846
	21st to end	Day	5% 4 2 5% 5% 5% 5% 5% 7% 9% 49%	4290
September	1st to 10th	Day	9% 7% 2 7% 6% 5% 4 4 6% 7% 43%	2200
	11th to 20th	Day	9% 6% 2 7% 4 5% 5% 4 6% 9% 43%	2200
	21st to end	Day	9% 6% 2 5% 4 5% 4 4 6% 7% 49%	2200
October	1st to 10th	Day	5% 4 2 4 3 4 4 3 6% 7% 58%	2200
	11th to 20th	Day	11% 5% 1 5% 3 4 3 3 4 5% 57%	2172
	21st to end	Day	10% 5% 2 5% 3 2 2 2 4 5% 60%	2200
November	1st to 10th	Day	12% 7% 1 4 3 3 4 3 5% 7% 52%	1984
	11th to 20th	Day	8% 6% 2 4 4 4 3 3 4 7% 56%	1890
	21st to end	Day	13% 7% 3 6% 3 3 4 2 5% 6% 50%	1890
December	1st to 10th	Day	20% 8% 3 6% 3 3 2 2 4 5% 43%	3030
	11th to 20th	Day	10% 8% 3 7% 4 4 4 3 6% 5% 47%	3481
	21st to end	Day	9% 6% 2 4 2 2 2 2 3 4 63%	4587
January	1st to 10th	Night	9% 4 2 6% 2 3 3 2 3 6% 60%	7634
	11th to 20th	Night	8% 4 2 3 2 2 2 2 4 5% 66%	7578
	21st to end	Night	23% 7% 2 5% 3 3 3 2 3 5% 45%	7746
February	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 5% 6% 55%	2520
	11th to 20th	Night	11% 6% 2 5% 3 3 4 2 5% 6% 53%	2458
	21st to end	Night	11% 5% 2 5% 3 3 3 3 5% 5% 53%	2076
March	1st to 10th	Night	7% 6% 2 5% 4 4 4 3 6% 7% 51%	5315
	11th to 20th	Night	9% 8% 2 5% 3 3 3 2 4 5% 55%	5090
	21st to end	Night	9% 9% 2 5% 3 3 3 3 5% 6% 52%	5588
April	1st to 10th	Night	7% 6% 2 6% 5% 4 4 4 5% 7% 51%	2310
	11th to 20th	Night	11% 8% 2 7% 4 3 3 3 4 5% 49%	2092
	21st to end	Night	13% 7% 2 4 4 3 4 3 4 6% 50%	2062
May	1st to 10th	Night	15% 9% 3 7% 3 3 4 3 4 6% 42%	4143
	11th to 20th	Night	6% 5% 2 5% 3 4 4 4 6% 8% 53%	4107
	21st to end	Night	9% 7% 2 6% 3 4 4 4 7% 10% 42%	4443
June	1st to 10th	Night	2 3 1 3 2 3 4 4 7% 11% 61%	1800
	11th to 20th	Night	3 3 1 4 3 3 4 4 6% 9% 60%	1800
	21st to end	Night	4 5% 2 5% 4 3 4 3 6% 10% 55%	1800
July	1st to 10th	Night	9% 6% 2 6% 5% 4 5% 4 6% 9% 45%	4078
	11th to 20th	Night	3 3 1 4 4 4 4 4 6% 10% 58%	4077
	21st to end	Night	4 6% 2 5% 3 4 4 3 6% 9% 54%	4449
August	1st to 10th	Night	1 1 1 2 2 3 3 3 4 8% 73%	3244
	11th to 20th	Night	2 2 1 3 3 3 4 3 6% 9% 63%	3213
	21st to end	Night	4 4 2 5% 4 4 4 4 7% 10% 53%	3615
September	1st to 10th	Night	8% 6% 2 5% 3 3 4 3 6% 9% 51%	2200
	11th to 20th	Night	9% 6% 2 5% 3 4 4 4 6% 8% 49%	2200
	21st to end	Night	8% 4 2 4 4 4 3 4 6% 7% 54%	2200
October	1st to 10th	Night	4 4 1 4 3 3 3 3 5% 7% 64%	2200
	11th to 20th	Night	9% 4 2 4 3 3 3 2 4 6% 58%	2205
	21st to end	Night	10% 5% 2 4 3 3 2 2 3 4 63%	2640
November	1st to 10th	Night	10% 6% 1 5% 3 3 2 2 4 5% 59%	2528
	11th to 20th	Night	8% 6% 2 3 3 2 3 3 4 7% 59%	2730
	21st to end	Night	13% 6% 2 5% 3 3 3 3 5% 6% 51%	2730
December	1st to 10th	Night	21% 6% 3 5% 3 3 3 3 4 5% 43%	4380
	11th to 20th	Night	13% 10% 2 5% 3 3 3 2 4 5% 50%	4946
	21st to end	Night	9% 7% 2 4 2 2 2 2 3 5% 61%	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	29% 2 5% 23% 26% 15%	5290
	11th to 20th	Day	30% 2 4 15% 26% 23%	5467
	21st to end	Day	40% 3 4 14% 26% 12%	6468
February	1st to 10th	Day	35% 4 6% 13% 22% 21%	2100
	11th to 20th	Day	36% 5% 6% 19% 19% 16%	2059
	21st to end	Day	31% 3 7% 16% 25% 19%	1730
March	1st to 10th	Day	31% 3 5% 16% 16% 29%	4769
	11th to 20th	Day	34% 3 5% 9% 16% 33%	5090
	21st to end	Day	32% 5% 8% 18% 20% 18%	5585
April	1st to 10th	Day	37% 4 9% 17% 18% 15%	2310
	11th to 20th	Day	40% 4 7% 16% 19% 14%	2473
	21st to end	Day	38% 4 9% 19% 18% 12%	2557
May	1st to 10th	Day	43% 5% 9% 17% 19% 8%	6030
	11th to 20th	Day	33% 6% 10% 16% 23% 13%	5945
	21st to end	Day	40% 7% 11% 24% 15% 3	6447
June	1st to 10th	Day	28% 6% 13% 30% 20% 3	2600
	11th to 20th	Day	30% 6% 12% 25% 20% 6%	2600
	21st to end	Day	35% 9% 12% 23% 17% 5%	2600
July	1st to 10th	Day	43% 7% 15% 28% 6%	5836
	11th to 20th	Day	31% 6% 15% 32% 14% 2	5831
	21st to end	Day	28% 7% 18% 27% 18% 1	6240
August	1st to 10th	Day	14% 5% 10% 39% 30% 1	3897
	11th to 20th	Day	21% 5% 21% 38% 12% 2	3882
	21st to end	Day	29% 10% 16% 25% 19% 2	4289
September	1st to 10th	Day	40% 6% 10% 19% 17% 8%	2200
	11th to 20th	Day	37% 6% 13% 21% 18% 5%	2200
	21st to end	Day	34% 5% 9% 21% 19% 12%	2200
October	1st to 10th	Day	16% 4 7% 14% 26% 32%	3590
	11th to 20th	Day	28% 3 6% 19% 22% 23%	3516
	21st to end	Day	24% 3 5% 17% 38% 13%	3538
November	1st to 10th	Day	34% 5% 7% 19% 22% 13%	1984
	11th to 20th	Day	31% 4 7% 18% 22% 19%	1890
	21st to end	Day	38% 4 6% 17% 22% 14%	1890
December	1st to 10th	Day	46% 2 6% 17% 19% 11%	3030
	11th to 20th	Day	39% 4 8% 12% 22% 15%	3479
	21st to end	Day	28% 2 4 17% 28% 22%	4587
January	1st to 10th	Night	29% 2 6% 17% 29% 16%	7635
	11th to 20th	Night	22% 1 3 16% 30% 26%	7578
	21st to end	Night	45% 2 3 10% 22% 17%	7746
February	1st to 10th	Night	32% 3 8% 13% 22% 22%	2520
	11th to 20th	Night	34% 4 7% 18% 21% 17%	2458
	21st to end	Night	34% 4 7% 13% 23% 19%	2076
March	1st to 10th	Night	31% 4 7% 18% 20% 19%	5315
	11th to 20th	Night	34% 3 6% 11% 15% 31%	5090
	21st to end	Night	35% 4 7% 18% 19% 18%	5588
April	1st to 10th	Night	34% 5% 10% 18% 15% 18%	2310
	11th to 20th	Night	39% 5% 9% 14% 17% 16%	2092
	21st to end	Night	39% 4 10% 18% 18% 11%	2062
May	1st to 10th	Night	44% 5% 8% 17% 13% 12%	4170
	11th to 20th	Night	30% 5% 12% 19% 20% 14%	4108
	21st to end	Night	37% 7% 15% 24% 12% 5%	4452
June	1st to 10th	Night	18% 7% 20% 34% 20% 2	1800
	11th to 20th	Night	22% 7% 15% 27% 23% 6%	1800
	21st to end	Night	26% 6% 19% 28% 17% 4	1800
July	1st to 10th	Night	36% 9% 21% 29% 5%	4035
	11th to 20th	Night	22% 7% 20% 34% 15% 1	4026
	21st to end	Night	28% 7% 21% 27% 15% 2	4320
August	1st to 10th	Night	12% 4 16% 43% 24% 1	3234
	11th to 20th	Night	18% 6% 26% 38% 11% 1	3243
	21st to end	Night	26% 10% 20% 25% 17% 2	3615
September	1st to 10th	Night	31% 8% 12% 23% 19% 8%	2200
	11th to 20th	Night	33% 8% 16% 23% 15% 6%	2200
	21st to end	Night	29% 6% 12% 22% 19% 12%	2200
October	1st to 10th	Night	14% 3 9% 16% 23% 35%	3590
	11th to 20th	Night	23% 4 9% 16% 28% 20%	3587
	21st to end	Night	24% 2 6% 19% 34% 16%	4252
November	1st to 10th	Night	30% 3 7% 19% 24% 15%	2528
	11th to 20th	Night	27% 4 7% 22% 21% 19%	2730
	21st to end	Night	36% 4 8% 16% 22% 16%	2730
December	1st to 10th	Night	45% 4 7% 15% 16% 13%	4380
	11th to 20th	Night	38% 3 6% 13% 21% 19%	4947
	21st to end	Night	30% 3 4 16% 29% 19%	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	14% 15% 42% 22% 7% 1	330
	11th to 20th	Day	16% 14% 36% 26% 6% 1	330
	21st to end	Day	15% 13% 46% 19% 7%	363
February	1st to 10th	Day	21% 11% 34% 25% 10%	330
	11th to 20th	Day	19% 14% 40% 22% 4	330
	21st to end	Day	17% 15% 45% 20% 3	273
March	1st to 10th	Day	18% 17% 41% 20% 4	330
	11th to 20th	Day	15% 14% 42% 20% 8%	330
	21st to end	Day	11% 15% 44% 23% 6% 1	363
April	1st to 10th	Day	17% 18% 40% 23% 3	330
	11th to 20th	Day	14% 18% 41% 22% 5%	511
	21st to end	Day	14% 16% 42% 22% 5%	577
May	1st to 10th	Day	15% 12% 40% 28% 5%	753
	11th to 20th	Day	15% 10% 35% 30% 9% 1	756
	21st to end	Day	13% 8% 31% 37% 10% 1	789
June	1st to 10th	Day	5% 3 21% 48% 21% 3	730
	11th to 20th	Day	6% 3 23% 47% 17% 4	730
	21st to end	Day	4 3 17% 38% 30% 7%	730
July	1st to 10th	Day	11% 3 10% 35% 32% 9%	721
	11th to 20th	Day	6% 1 6% 42% 39% 7%	718
	21st to end	Day	3 1 7% 37% 40% 12%	794
August	1st to 10th	Day	2 3 36% 46% 13%	533
	11th to 20th	Day	6% 1 4 33% 40% 15%	517
	21st to end	Day	5% 1 5% 27% 44% 18%	574
September	1st to 10th	Day	11% 1 8% 27% 36% 18%	330
	11th to 20th	Day	5% 6% 29% 44% 16%	330
	21st to end	Day	10% 2 7% 31% 37% 13%	330
October	1st to 10th	Day	4 3 13% 34% 37% 9%	330
	11th to 20th	Day	9% 3 20% 43% 22% 3	330
	21st to end	Day	15% 10% 27% 32% 13% 3	363
November	1st to 10th	Day	17% 7% 28% 30% 15% 2	330
	11th to 20th	Day	17% 10% 27% 28% 13% 5%	330
	21st to end	Day	21% 14% 37% 18% 8% 3	330
December	1st to 10th	Day	18% 8% 33% 28% 11% 3	330
	11th to 20th	Day	12% 18% 34% 25% 10% 1	330
	21st to end	Day	12% 12% 35% 32% 9%	363
January	1st to 10th	Night	14% 10% 37% 31% 8%	1050
	11th to 20th	Night	15% 10% 39% 30% 5%	1013
	21st to end	Night	17% 11% 38% 27% 6%	924
February	1st to 10th	Night	14% 14% 37% 29% 7%	840
	11th to 20th	Night	15% 16% 39% 27% 3	824
	21st to end	Night	15% 13% 49% 21% 1	692
March	1st to 10th	Night	16% 15% 42% 24% 3	765
	11th to 20th	Night	14% 12% 40% 29% 4	630
	21st to end	Night	9% 14% 50% 24% 3	693
April	1st to 10th	Night	9% 13% 51% 23% 3	630
	11th to 20th	Night	13% 17% 49% 20% 1	623
	21st to end	Night	15% 12% 47% 21% 4	630
May	1st to 10th	Night	11% 15% 46% 25% 3	630
	11th to 20th	Night	10% 10% 40% 31% 8% 1	609
	21st to end	Night	10% 7% 41% 34% 8%	650
June	1st to 10th	Night	3 2 30% 51% 14%	600
	11th to 20th	Night	4 2 37% 48% 9%	600
	21st to end	Night	5% 2 22% 49% 21% 1	600
July	1st to 10th	Night	8% 3 13% 51% 24% 2	585
	11th to 20th	Night	3 1 12% 58% 24% 1	582
	21st to end	Night	5% 1 8% 58% 26% 3	657
August	1st to 10th	Night	1 1 6% 58% 33% 2	597
	11th to 20th	Night	4 1 7% 51% 34% 3	594
	21st to end	Night	5% 1 8% 44% 38% 4	660
September	1st to 10th	Night	10% 1 8% 43% 35% 3	600
	11th to 20th	Night	10% 2 9% 41% 36% 3	600
	21st to end	Night	7% 2 13% 46% 31% 2	600
October	1st to 10th	Night	5% 2 16% 47% 28% 2	600
	11th to 20th	Night	11% 4 24% 42% 18% 1	605
	21st to end	Night	13% 9% 29% 30% 18% 2	880
November	1st to 10th	Night	13% 6% 26% 40% 14% 2	888
	11th to 20th	Night	10% 6% 33% 35% 13% 2	1050
	21st to end	Night	17% 8% 33% 31% 10% 1	1050
December	1st to 10th	Night	15% 7% 32% 37% 8% 1	1050
	11th to 20th	Night	17% 10% 33% 33% 7%	1050
	21st to end	Night	13% 11% 35% 35% 7%	1155

Page generated at 2026-05-14 00:58:57. Version ac07

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