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 2024-01-17.

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	13% 5% 2 4 4 3 4 4 5% 7% 49%	74865
	Night	11% 4 2 4 4 2 3 4 5% 7% 54%	74984
Transparency	Day	34% 5% 10% 21% 19% 11%	74594
	Night	30% 5% 11% 21% 20% 14%	74775
Seeing	Day	13% 5% 18% 32% 26% 6%	13577
	Night	13% 4 22% 42% 17% 1	23688

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	14% 6% 2 3 3 2 2 3 3 6% 55%	1707
	11th to 20th	Day	18% 5% 2 4 3 2 3 3 4 6% 50%	1779
	21st to end	Day	14% 5% 2 4 4 2 3 4 4 7% 51%	1980
February	1st to 10th	Day	17% 7% 3 4 3 2 3 4 3 6% 49%	1800
	11th to 20th	Day	17% 6% 3 5% 4 3 3 3 5% 6% 47%	1749
	21st to end	Day	16% 5% 2 3 3 2 3 3 4 6% 53%	1480
March	1st to 10th	Day	19% 6% 3 4 4 2 3 3 4 6% 46%	1854
	11th to 20th	Day	16% 6% 3 5% 4 3 4 4 4 6% 47%	1980
	21st to end	Day	19% 5% 2 3 4 3 3 3 4 5% 50%	2178
April	1st to 10th	Day	15% 6% 2 4 4 2 4 3 5% 7% 47%	1980
	11th to 20th	Day	16% 5% 2 3 4 3 3 4 5% 6% 50%	2121
	21st to end	Day	16% 6% 2 5% 5% 2 3 4 4 5% 48%	2160
May	1st to 10th	Day	16% 4 2 4 4 2 4 4 6% 7% 45%	2326
	11th to 20th	Day	15% 6% 3 4 4 3 5% 4 5% 9% 41%	2302
	21st to end	Day	16% 6% 3 6% 7% 3 5% 4 5% 7% 39%	2531
June	1st to 10th	Day	6% 3 2 3 3 3 4 5% 7% 10% 53%	2340
	11th to 20th	Day	7% 3 3 3 4 3 4 5% 6% 9% 53%	2340
	21st to end	Day	7% 4 3 4 6% 4 7% 5% 6% 9% 43%	2340
July	1st to 10th	Day	12% 6% 3 5% 5% 4 5% 5% 6% 8% 41%	2340
	11th to 20th	Day	5% 3 1 3 4 3 4 6% 5% 9% 57%	2340
	21st to end	Day	5% 2 1 2 4 2 5% 5% 6% 11% 56%	2475
August	1st to 10th	Day	2 1 1 2 3 2 4 4 7% 10% 64%	2149
	11th to 20th	Day	6% 3 1 3 4 3 4 5% 6% 9% 56%	2123
	21st to end	Day	8% 3 2 4 5% 3 6% 5% 7% 9% 50%	2372
September	1st to 10th	Day	10% 6% 3 6% 7% 3 6% 6% 5% 7% 41%	1980
	11th to 20th	Day	12% 6% 3 4 7% 4 3 5% 5% 8% 43%	1980
	21st to end	Day	10% 4 2 4 5% 3 6% 5% 5% 8% 49%	1980
October	1st to 10th	Day	8% 4 2 4 3 3 4 4 5% 8% 55%	1980
	11th to 20th	Day	15% 5% 2 4 4 3 3 4 4 6% 50%	1980
	21st to end	Day	13% 5% 2 3 3 2 3 3 4 5% 58%	1987
November	1st to 10th	Day	17% 6% 3 4 4 2 3 4 4 6% 46%	1806
	11th to 20th	Day	16% 6% 3 4 4 2 4 4 4 5% 49%	1710
	21st to end	Day	18% 6% 3 5% 4 2 4 3 3 4 48%	1710
December	1st to 10th	Day	18% 7% 3 4 3 2 2 4 4 5% 48%	1710
	11th to 20th	Day	18% 6% 3 5% 4 3 3 4 3 4 46%	2161
	21st to end	Day	15% 6% 2 3 3 2 3 3 3 5% 56%	3135
January	1st to 10th	Night	14% 4 2 3 3 2 3 3 3 5% 57%	2458
	11th to 20th	Night	15% 4 2 4 4 2 3 4 4 5% 53%	2340
	21st to end	Night	17% 5% 3 3 3 2 3 3 4 6% 51%	2376
February	1st to 10th	Night	13% 5% 2 3 3 3 3 3 4 6% 56%	2160
	11th to 20th	Night	17% 6% 2 3 3 2 2 3 4 6% 54%	2098
	21st to end	Night	14% 5% 2 4 4 3 3 3 4 7% 51%	1776
March	1st to 10th	Night	14% 6% 2 4 5% 2 4 4 5% 7% 47%	2104
	11th to 20th	Night	14% 6% 2 5% 4 2 4 4 4 6% 50%	1980
	21st to end	Night	12% 4 2 3 3 2 3 4 5% 8% 54%	2178
April	1st to 10th	Night	10% 5% 2 3 3 2 3 5% 7% 8% 52%	1980
	11th to 20th	Night	16% 4 2 4 4 2 4 3 4 6% 51%	1784
	21st to end	Night	14% 5% 3 4 4 2 3 4 4 6% 52%	1800
May	1st to 10th	Night	10% 4 2 5% 4 3 3 5% 5% 7% 51%	1630
	11th to 20th	Night	13% 5% 2 5% 4 3 3 4 6% 8% 49%	1593
	21st to end	Night	11% 5% 2 4 4 4 4 5% 6% 8% 48%	1745
June	1st to 10th	Night	3 3 1 2 3 1 4 4 5% 10% 65%	1620
	11th to 20th	Night	3 2 1 3 4 3 4 4 6% 11% 59%	1620
	21st to end	Night	6% 3 2 4 4 2 5% 5% 6% 10% 54%	1620
July	1st to 10th	Night	8% 5% 2 5% 5% 3 5% 5% 6% 10% 47%	1620
	11th to 20th	Night	2 3 1 2 3 2 3 5% 6% 9% 63%	1620
	21st to end	Night	4 1 1 3 3 2 4 5% 7% 12% 58%	1837
August	1st to 10th	Night	2 1 1 1 2 2 3 3 4 8% 73%	1790
	11th to 20th	Night	5% 3 1 3 4 3 4 4 5% 11% 58%	1778
	21st to end	Night	5% 4 2 5% 5% 3 5% 5% 5% 9% 52%	1983
September	1st to 10th	Night	8% 4 2 5% 5% 3 6% 5% 6% 8% 47%	1980
	11th to 20th	Night	11% 6% 2 5% 5% 3 4 5% 4 9% 46%	1980
	21st to end	Night	9% 5% 2 4 4 3 4 4 5% 8% 52%	1980
October	1st to 10th	Night	7% 3 2 3 3 2 3 4 4 7% 61%	1980
	11th to 20th	Night	13% 4 2 3 3 2 3 3 4 6% 56%	1980
	21st to end	Night	12% 3 1 2 3 1 2 2 3 5% 65%	2348
November	1st to 10th	Night	14% 5% 1 3 3 2 3 3 4 5% 56%	2268
	11th to 20th	Night	11% 5% 2 4 3 2 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% 5% 2 3 3 2 3 3 4 6% 53%	2470
	11th to 20th	Night	17% 6% 2 4 4 2 3 3 3 5% 50%	3036
	21st to end	Night	16% 4 2 3 3 2 3 3 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	32% 3 5% 17% 23% 20%	1708
	11th to 20th	Day	38% 2 5% 15% 20% 19%	1779
	21st to end	Day	35% 3 7% 14% 23% 18%	1980
February	1st to 10th	Day	40% 3 5% 12% 19% 20%	1800
	11th to 20th	Day	39% 3 6% 16% 21% 14%	1759
	21st to end	Day	34% 4 8% 16% 21% 18%	1480
March	1st to 10th	Day	42% 4 8% 16% 17% 13%	1854
	11th to 20th	Day	38% 5% 8% 14% 15% 20%	1980
	21st to end	Day	37% 4 8% 16% 18% 17%	2178
April	1st to 10th	Day	38% 4 9% 17% 19% 14%	1980
	11th to 20th	Day	36% 5% 6% 19% 17% 16%	2121
	21st to end	Day	38% 4 6% 20% 17% 16%	2160
May	1st to 10th	Day	37% 5% 9% 20% 18% 10%	2326
	11th to 20th	Day	39% 7% 9% 21% 18% 5%	2306
	21st to end	Day	43% 6% 9% 21% 17% 3	2531
June	1st to 10th	Day	22% 8% 14% 30% 21% 5%	2340
	11th to 20th	Day	27% 7% 13% 28% 19% 6%	2340
	21st to end	Day	34% 8% 14% 23% 17% 5%	2340
July	1st to 10th	Day	39% 7% 15% 23% 13% 2	2276
	11th to 20th	Day	22% 7% 17% 28% 22% 3	2271
	21st to end	Day	19% 8% 20% 36% 15% 1	2337
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	30% 3 6% 16% 22% 22%	2458
	11th to 20th	Night	34% 3 6% 16% 20% 20%	2340
	21st to end	Night	36% 3 5% 14% 20% 22%	2376
February	1st to 10th	Night	31% 3 7% 16% 18% 24%	2160
	11th to 20th	Night	35% 3 6% 18% 19% 19%	2098
	21st to end	Night	35% 4 7% 14% 20% 19%	1776
March	1st to 10th	Night	36% 5% 10% 16% 18% 15%	2104
	11th to 20th	Night	36% 6% 9% 12% 17% 21%	1980
	21st to end	Night	29% 5% 13% 19% 16% 18%	2178
April	1st to 10th	Night	29% 6% 11% 19% 18% 16%	1980
	11th to 20th	Night	35% 4 10% 17% 15% 19%	1784
	21st to end	Night	34% 4 10% 20% 16% 16%	1800
May	1st to 10th	Night	31% 7% 12% 21% 16% 13%	1630
	11th to 20th	Night	32% 7% 12% 23% 20% 6%	1594
	21st to end	Night	33% 7% 14% 27% 16% 3	1746
June	1st to 10th	Night	16% 6% 17% 33% 24% 3	1620
	11th to 20th	Night	19% 7% 13% 29% 25% 7%	1620
	21st to end	Night	25% 9% 18% 25% 18% 5%	1620
July	1st to 10th	Night	33% 8% 21% 23% 14% 2	1575
	11th to 20th	Night	16% 8% 18% 29% 25% 3	1566
	21st to end	Night	16% 7% 26% 35% 16% 2	1735
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	20% 8% 22% 34% 15% 1	258
	21st to end	Day	16% 6% 33% 33% 12%	264
February	1st to 10th	Day	25% 9% 23% 26% 17% 1	240
	11th to 20th	Day	22% 7% 33% 25% 9% 3	240
	21st to end	Day	25% 10% 37% 20% 7%	198
March	1st to 10th	Day	23% 11% 34% 28% 5%	240
	11th to 20th	Day	18% 9% 39% 22% 12%	240
	21st to end	Day	22% 10% 33% 28% 6%	264
April	1st to 10th	Day	15% 9% 35% 33% 8%	240
	11th to 20th	Day	11% 13% 36% 31% 9%	399
	21st to end	Day	12% 10% 39% 31% 7%	420
May	1st to 10th	Day	19% 6% 30% 35% 10% 1	589
	11th to 20th	Day	20% 6% 26% 34% 12% 2	625
	21st to end	Day	16% 4 25% 39% 14% 1	679
June	1st to 10th	Day	5% 3 15% 45% 26% 6%	630
	11th to 20th	Day	8% 2 11% 49% 26% 4	630
	21st to end	Day	8% 2 10% 35% 37% 8%	630
July	1st to 10th	Day	11% 3 6% 32% 40% 9%	621
	11th to 20th	Day	4 1 3 29% 54% 9%	618
	21st to end	Day	3 4 33% 47% 13%	613
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%	844
	21st to end	Night	20% 7% 23% 41% 9%	792
February	1st to 10th	Night	18% 6% 28% 39% 8% 1	720
	11th to 20th	Night	21% 6% 31% 34% 8%	704
	21st to end	Night	17% 7% 35% 38% 3	592
March	1st to 10th	Night	18% 8% 36% 31% 6%	664
	11th to 20th	Night	16% 10% 33% 36% 5%	540
	21st to end	Night	13% 8% 43% 31% 6%	594
April	1st to 10th	Night	10% 7% 43% 37% 3	540
	11th to 20th	Night	16% 8% 44% 30% 2	533
	21st to end	Night	13% 9% 41% 33% 4	540
May	1st to 10th	Night	10% 6% 45% 36% 3	540
	11th to 20th	Night	13% 6% 34% 39% 7%	531
	21st to end	Night	11% 4 35% 41% 9%	584
June	1st to 10th	Night	4 2 25% 53% 15% 1	540
	11th to 20th	Night	3 1 27% 58% 11%	540
	21st to end	Night	6% 1 17% 55% 20% 1	540
July	1st to 10th	Night	8% 3 8% 55% 24% 1	525
	11th to 20th	Night	3 1 9% 55% 31% 1	522
	21st to end	Night	4 1 8% 54% 32%	591
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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