Uvalde
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Uvalde clear sky chart from 2005-11-06 to 2024-07-31.

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	13% 6% 2 5% 4 4 4 3 5% 7% 49%	90161
	Night	12% 5% 2 4 3 3 3 3 5% 7% 54%	89705
Transparency	Day	34% 5% 10% 20% 19% 11%	89940
	Night	30% 5% 11% 20% 20% 14%	89531
Seeing	Day	13% 5% 19% 32% 25% 6%	14365
	Night	13% 5% 23% 42% 16% 1	24325

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	12% 6% 2 3 2 2 2 2 3 5% 61%	2847
	11th to 20th	Day	14% 5% 1 3 2 2 2 2 4 5% 58%	3024
	21st to end	Day	16% 6% 2 5% 3 3 3 2 4 9% 45%	3487
February	1st to 10th	Day	16% 8% 2 5% 3 2 3 3 4 5% 48%	1900
	11th to 20th	Day	16% 6% 3 5% 3 3 3 3 5% 6% 47%	1849
	21st to end	Day	15% 6% 1 3 3 3 3 3 4 6% 53%	1570
March	1st to 10th	Day	17% 8% 2 5% 4 2 3 2 4 6% 46%	3236
	11th to 20th	Day	23% 9% 3 7% 4 3 3 2 4 5% 37%	3480
	21st to end	Day	16% 5% 2 4 3 3 3 3 5% 6% 50%	3814
April	1st to 10th	Day	14% 7% 2 5% 4 3 3 3 5% 7% 47%	2090
	11th to 20th	Day	16% 5% 2 4 4 4 3 3 5% 5% 49%	2241
	21st to end	Day	16% 6% 2 6% 5% 3 3 3 4 5% 47%	2280
May	1st to 10th	Day	22% 6% 2 6% 4 3 3 3 5% 7% 39%	4068
	11th to 20th	Day	14% 6% 2 5% 4 5% 4 3 5% 8% 45%	4082
	21st to end	Day	11% 5% 2 6% 5% 5% 5% 4 6% 9% 43%	4477
June	1st to 10th	Day	6% 4 2 3 3 4 4 4 7% 10% 53%	2470
	11th to 20th	Day	7% 4 2 4 3 4 5% 4 6% 8% 52%	2470
	21st to end	Day	6% 5% 2 5% 6% 6% 6% 4 7% 9% 43%	2470
July	1st to 10th	Day	11% 7% 2 5% 6% 4 5% 4 6% 7% 43%	2470
	11th to 20th	Day	6% 4 1 3 3 4 4 4 6% 9% 56%	2470
	21st to end	Day	5% 3 1 3 4 4 4 4 7% 10% 54%	2603
August	1st to 10th	Day	2 2 1 2 2 3 4 3 7% 10% 64%	2149
	11th to 20th	Day	6% 3 1 4 4 4 4 4 6% 9% 55%	2123
	21st to end	Day	7% 3 2 5% 4 5% 5% 4 7% 9% 50%	2372
September	1st to 10th	Day	10% 7% 3 6% 6% 5% 6% 4 5% 7% 41%	1980
	11th to 20th	Day	12% 6% 3 6% 6% 4 4 4 6% 8% 42%	1980
	21st to end	Day	10% 4 2 5% 4 5% 6% 4 5% 7% 49%	1980
October	1st to 10th	Day	8% 4 2 4 3 4 4 3 5% 8% 54%	1980
	11th to 20th	Day	15% 5% 2 4 4 3 3 3 4 6% 50%	1980
	21st to end	Day	13% 5% 1 3 3 3 3 2 4 4 58%	1987
November	1st to 10th	Day	17% 7% 2 5% 3 3 3 3 4 6% 46%	1806
	11th to 20th	Day	16% 6% 3 4 3 3 4 3 4 5% 49%	1710
	21st to end	Day	18% 6% 2 6% 3 3 4 2 3 4 48%	1710
December	1st to 10th	Day	18% 8% 3 4 3 2 2 3 4 5% 48%	1710
	11th to 20th	Day	18% 7% 2 5% 3 4 3 3 3 5% 46%	2161
	21st to end	Day	15% 6% 2 4 3 3 2 2 4 5% 55%	3135
January	1st to 10th	Night	14% 4 1 4 2 2 2 2 3 6% 58%	4108
	11th to 20th	Night	11% 3 1 3 2 2 2 2 2 4 68%	3961
	21st to end	Night	19% 7% 2 4 3 3 3 2 4 6% 47%	4180
February	1st to 10th	Night	13% 6% 1 4 2 3 2 2 4 6% 56%	2280
	11th to 20th	Night	17% 7% 1 3 3 3 3 2 3 6% 54%	2218
	21st to end	Night	13% 6% 2 4 4 3 4 3 4 7% 51%	1884
March	1st to 10th	Night	12% 7% 2 5% 4 4 4 3 5% 7% 47%	3622
	11th to 20th	Night	18% 8% 3 8% 3 3 4 3 4 5% 42%	3480
	21st to end	Night	12% 5% 1 5% 3 3 3 3 5% 7% 51%	3817
April	1st to 10th	Night	10% 5% 1 4 3 3 3 4 7% 7% 52%	2090
	11th to 20th	Night	15% 5% 2 6% 3 3 4 3 4 6% 49%	1884
	21st to end	Night	15% 6% 2 5% 4 3 2 3 4 6% 50%	1900
May	1st to 10th	Night	17% 6% 2 5% 3 3 3 3 5% 6% 47%	2833
	11th to 20th	Night	12% 4 2 5% 3 3 3 3 5% 7% 54%	2823
	21st to end	Night	9% 4 2 5% 3 4 3 3 5% 8% 52%	3090
June	1st to 10th	Night	3 3 1 2 3 2 4 3 5% 10% 64%	1710
	11th to 20th	Night	4 2 1 4 4 4 4 4 6% 10% 58%	1710
	21st to end	Night	5% 4 1 5% 3 4 4 4 6% 10% 53%	1710
July	1st to 10th	Night	7% 6% 1 6% 4 4 4 4 6% 9% 48%	1710
	11th to 20th	Night	2 3 1 3 3 3 3 4 7% 8% 62%	1710
	21st to end	Night	5% 2 1 3 4 3 4 4 7% 11% 56%	1940
August	1st to 10th	Night	2 1 1 2 2 3 3 4 9% 72%	1790
	11th to 20th	Night	5% 3 1 4 3 4 3 3 6% 10% 58%	1778
	21st to end	Night	5% 4 1 5% 4 5% 4 4 6% 9% 52%	1983
September	1st to 10th	Night	7% 5% 1 5% 5% 5% 5% 4 6% 8% 47%	1980
	11th to 20th	Night	10% 6% 2 6% 4 5% 4 4 5% 9% 46%	1980
	21st to end	Night	9% 5% 2 5% 3 4 4 4 5% 8% 52%	1980
October	1st to 10th	Night	7% 4 1 3 3 3 4 3 4 7% 61%	1980
	11th to 20th	Night	13% 4 2 3 3 3 3 3 4 6% 56%	1980
	21st to end	Night	12% 3 1 3 2 2 2 2 3 5% 65%	2348
November	1st to 10th	Night	14% 6% 1 4 3 3 2 2 4 5% 56%	2268
	11th to 20th	Night	11% 5% 2 5% 3 3 3 3 4 5% 56%	2470
	21st to end	Night	17% 4 2 4 3 3 3 4 4 6% 50%	2470
December	1st to 10th	Night	15% 6% 2 4 3 3 3 3 4 6% 52%	2470
	11th to 20th	Night	17% 6% 2 5% 3 3 3 2 3 5% 50%	3036
	21st to end	Night	16% 4 2 4 2 3 2 2 5% 7% 53%	4532

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	28% 2 4 15% 28% 24%	2848
	11th to 20th	Day	29% 2 5% 16% 25% 23%	3024
	21st to end	Day	38% 4 7% 15% 26% 10%	3487
February	1st to 10th	Day	40% 3 6% 13% 19% 20%	1900
	11th to 20th	Day	38% 3 6% 16% 21% 15%	1859
	21st to end	Day	33% 4 8% 17% 21% 17%	1570
March	1st to 10th	Day	42% 4 6% 14% 19% 14%	3236
	11th to 20th	Day	50% 5% 7% 10% 16% 13%	3480
	21st to end	Day	34% 4 9% 16% 16% 21%	3814
April	1st to 10th	Day	37% 4 8% 16% 18% 16%	2090
	11th to 20th	Day	36% 6% 7% 19% 17% 16%	2241
	21st to end	Day	38% 4 6% 19% 17% 15%	2280
May	1st to 10th	Day	44% 5% 9% 18% 14% 10%	4106
	11th to 20th	Day	37% 6% 9% 21% 17% 9%	4086
	21st to end	Day	35% 7% 11% 30% 15% 2	4489
June	1st to 10th	Day	22% 8% 14% 30% 21% 5%	2470
	11th to 20th	Day	27% 7% 13% 27% 19% 7%	2470
	21st to end	Day	34% 7% 14% 23% 17% 4	2470
July	1st to 10th	Day	38% 7% 15% 25% 13% 2	2406
	11th to 20th	Day	23% 7% 17% 28% 22% 3	2401
	21st to end	Day	20% 8% 20% 35% 16% 1	2465
August	1st to 10th	Day	15% 6% 15% 40% 21% 2	2136
	11th to 20th	Day	24% 8% 16% 33% 15% 4	2123
	21st to end	Day	29% 8% 16% 26% 17% 4	2372
September	1st to 10th	Day	41% 7% 12% 18% 16% 5%	1980
	11th to 20th	Day	38% 7% 12% 21% 18% 4	1980
	21st to end	Day	32% 8% 11% 21% 18% 10%	1980
October	1st to 10th	Day	27% 6% 11% 23% 25% 8%	1980
	11th to 20th	Day	35% 4 9% 17% 20% 14%	1980
	21st to end	Day	31% 3 5% 16% 25% 20%	1987
November	1st to 10th	Day	39% 5% 8% 19% 18% 11%	1806
	11th to 20th	Day	37% 4 8% 16% 20% 15%	1710
	21st to end	Day	42% 3 4 18% 18% 15%	1710
December	1st to 10th	Day	39% 4 8% 16% 22% 11%	1710
	11th to 20th	Day	42% 3 7% 10% 20% 18%	2159
	21st to end	Day	34% 3 5% 15% 31% 13%	3135
January	1st to 10th	Night	28% 2 6% 13% 25% 25%	4108
	11th to 20th	Night	23% 2 4 18% 24% 29%	3961
	21st to end	Night	40% 2 5% 13% 25% 13%	4180
February	1st to 10th	Night	31% 3 7% 16% 19% 23%	2280
	11th to 20th	Night	35% 3 6% 18% 19% 19%	2218
	21st to end	Night	34% 4 7% 15% 21% 19%	1884
March	1st to 10th	Night	36% 6% 9% 16% 18% 15%	3622
	11th to 20th	Night	45% 5% 8% 14% 13% 15%	3480
	21st to end	Night	31% 6% 12% 19% 17% 17%	3817
April	1st to 10th	Night	29% 6% 11% 19% 18% 17%	2090
	11th to 20th	Night	36% 4 10% 16% 15% 19%	1884
	21st to end	Night	36% 4 10% 20% 16% 15%	1900
May	1st to 10th	Night	36% 6% 11% 20% 16% 12%	2860
	11th to 20th	Night	30% 7% 11% 20% 21% 11%	2824
	21st to end	Night	28% 7% 13% 29% 18% 6%	3099
June	1st to 10th	Night	16% 6% 17% 33% 24% 3	1710
	11th to 20th	Night	20% 6% 12% 29% 26% 7%	1710
	21st to end	Night	25% 9% 17% 26% 18% 5%	1710
July	1st to 10th	Night	32% 7% 21% 25% 13% 2	1665
	11th to 20th	Night	18% 8% 18% 29% 24% 3	1656
	21st to end	Night	18% 7% 25% 33% 16% 2	1838
August	1st to 10th	Night	11% 6% 19% 42% 20% 2	1779
	11th to 20th	Night	20% 8% 21% 31% 16% 3	1778
	21st to end	Night	27% 8% 19% 26% 16% 4	1983
September	1st to 10th	Night	32% 10% 15% 19% 17% 7%	1980
	11th to 20th	Night	36% 7% 16% 20% 17% 4	1980
	21st to end	Night	30% 6% 13% 22% 19% 11%	1980
October	1st to 10th	Night	24% 5% 11% 26% 22% 11%	1980
	11th to 20th	Night	30% 4 9% 20% 20% 16%	1980
	21st to end	Night	24% 3 7% 16% 26% 24%	2348
November	1st to 10th	Night	31% 4 7% 19% 24% 15%	2268
	11th to 20th	Night	30% 4 10% 18% 22% 17%	2470
	21st to end	Night	36% 4 8% 17% 19% 17%	2470
December	1st to 10th	Night	34% 4 7% 20% 20% 15%	2470
	11th to 20th	Night	38% 3 6% 15% 19% 19%	3037
	21st to end	Night	32% 4 6% 16% 25% 18%	4532

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% 9% 27% 33% 12%	270
	11th to 20th	Day	18% 8% 22% 36% 14% 1	270
	21st to end	Day	16% 6% 31% 32% 14%	297
February	1st to 10th	Day	24% 10% 23% 26% 16% 1	270
	11th to 20th	Day	21% 8% 34% 26% 9% 3	270
	21st to end	Day	24% 10% 36% 22% 8%	225
March	1st to 10th	Day	22% 11% 36% 25% 6%	270
	11th to 20th	Day	19% 10% 40% 22% 10%	270
	21st to end	Day	21% 11% 34% 28% 5%	297
April	1st to 10th	Day	15% 11% 35% 31% 8%	270
	11th to 20th	Day	12% 14% 37% 29% 8%	439
	21st to end	Day	12% 10% 40% 31% 7%	460
May	1st to 10th	Day	20% 7% 29% 35% 9% 1	639
	11th to 20th	Day	19% 7% 27% 34% 12% 1	675
	21st to end	Day	16% 4 27% 39% 13% 1	734
June	1st to 10th	Day	5% 3 16% 45% 25% 6%	680
	11th to 20th	Day	8% 2 13% 49% 24% 4	680
	21st to end	Day	8% 2 10% 35% 37% 8%	680
July	1st to 10th	Day	10% 3 6% 32% 40% 9%	671
	11th to 20th	Day	5% 1 3 29% 52% 10%	668
	21st to end	Day	3 1 5% 34% 45% 12%	661
August	1st to 10th	Day	2 1 2 32% 49% 14%	447
	11th to 20th	Day	8% 5% 25% 48% 14%	437
	21st to end	Day	5% 1 5% 29% 41% 19%	491
September	1st to 10th	Day	11% 5% 18% 42% 24%	270
	11th to 20th	Day	6% 1 3 20% 46% 24%	270
	21st to end	Day	11% 4 18% 50% 17%	270
October	1st to 10th	Day	9% 3 11% 27% 38% 12%	270
	11th to 20th	Day	12% 3 9% 41% 27% 7%	270
	21st to end	Day	19% 8% 21% 28% 19% 5%	297
November	1st to 10th	Day	20% 7% 17% 30% 21% 5%	270
	11th to 20th	Day	25% 7% 13% 30% 20% 6%	270
	21st to end	Day	23% 9% 28% 25% 11% 3	270
December	1st to 10th	Day	22% 3 19% 32% 19% 4	270
	11th to 20th	Day	23% 8% 21% 33% 15%	270
	21st to end	Day	20% 5% 25% 33% 14% 3	297
January	1st to 10th	Night	17% 4 23% 43% 12% 1	950
	11th to 20th	Night	17% 5% 25% 44% 9%	856
	21st to end	Night	20% 7% 24% 41% 8%	836
February	1st to 10th	Night	18% 7% 27% 39% 8% 1	760
	11th to 20th	Night	21% 7% 31% 34% 7%	744
	21st to end	Night	16% 7% 36% 38% 3	628
March	1st to 10th	Night	18% 9% 36% 31% 6%	700
	11th to 20th	Night	15% 10% 34% 36% 4	570
	21st to end	Night	14% 9% 43% 29% 5%	627
April	1st to 10th	Night	11% 8% 42% 36% 3	570
	11th to 20th	Night	16% 9% 44% 29% 2	563
	21st to end	Night	13% 10% 41% 32% 4	570
May	1st to 10th	Night	10% 7% 44% 35% 3	570
	11th to 20th	Night	13% 6% 35% 38% 7%	561
	21st to end	Night	11% 4 36% 40% 8%	617
June	1st to 10th	Night	4 3 26% 52% 14% 1	570
	11th to 20th	Night	3 2 28% 56% 11%	570
	21st to end	Night	6% 2 18% 54% 19% 1	570
July	1st to 10th	Night	8% 3 9% 55% 24% 1	555
	11th to 20th	Night	3 1 10% 54% 31% 1	552
	21st to end	Night	4 2 9% 54% 31%	624
August	1st to 10th	Night	1 7% 52% 38% 1	537
	11th to 20th	Night	6% 1 6% 51% 34% 2	534
	21st to end	Night	6% 2 7% 45% 38% 3	594
September	1st to 10th	Night	7% 1 6% 46% 36% 4	540
	11th to 20th	Night	11% 1 7% 42% 35% 4	540
	21st to end	Night	10% 1 10% 39% 34% 5%	540
October	1st to 10th	Night	6% 2 10% 50% 31% 1	540
	11th to 20th	Night	16% 3 16% 41% 21% 2	540
	21st to end	Night	11% 5% 20% 37% 23% 3	764
November	1st to 10th	Night	15% 3 15% 37% 28% 3	788
	11th to 20th	Night	13% 3 18% 44% 21% 2	950
	21st to end	Night	18% 4 21% 39% 17% 1	950
December	1st to 10th	Night	18% 4 17% 43% 16% 2	950
	11th to 20th	Night	22% 6% 19% 39% 13%	950
	21st to end	Night	17% 5% 22% 45% 11% 1	1045

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