Eagle Pass
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eagle Pass clear sky chart from 2005-11-06 to 2024-05-13.

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	11% 5% 2 5% 3 3 4 3 5% 7% 52%	84074
	Night	10% 4 2 4 3 3 3 3 5% 7% 56%	85507
Transparency	Day	32% 5% 10% 20% 20% 13%	83810
	Night	28% 5% 10% 20% 21% 15%	85291
Seeing	Day	11% 5% 19% 33% 26% 7%	13891
	Night	12% 4 22% 45% 17% 1	24035

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	11% 6% 2 3 3 2 2 2 3 5% 62%	2853
	11th to 20th	Day	10% 7% 2 3 2 2 2 3 5% 5% 61%	3170
	21st to end	Day	12% 7% 2 5% 4 4 3 3 6% 8% 45%	3487
February	1st to 10th	Day	11% 6% 2 6% 3 3 4 3 4 7% 50%	1900
	11th to 20th	Day	13% 7% 2 3 3 3 3 3 4 7% 52%	1849
	21st to end	Day	11% 4 1 4 3 3 3 3 6% 6% 56%	1570
March	1st to 10th	Day	14% 7% 2 5% 4 3 4 3 5% 6% 46%	3156
	11th to 20th	Day	21% 8% 3 6% 4 3 3 3 4 6% 40%	3480
	21st to end	Day	10% 5% 2 4 3 3 4 3 5% 7% 54%	3814
April	1st to 10th	Day	11% 6% 2 4 4 3 4 3 5% 7% 50%	2159
	11th to 20th	Day	12% 5% 2 4 3 4 3 3 5% 7% 51%	2254
	21st to end	Day	13% 6% 2 5% 3 3 3 3 5% 7% 50%	2280
May	1st to 10th	Day	14% 6% 2 4 4 4 3 3 5% 9% 45%	2373
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 6% 10% 41%	2330
	21st to end	Day	13% 7% 2 6% 5% 4 4 5% 6% 10% 39%	2531
June	1st to 10th	Day	4 3 1 4 3 3 4 4 7% 10% 58%	2340
	11th to 20th	Day	4 3 2 4 3 3 4 4 7% 10% 57%	2340
	21st to end	Day	5% 4 2 5% 6% 5% 6% 5% 6% 9% 48%	2340
July	1st to 10th	Day	10% 6% 2 5% 5% 5% 5% 4 6% 9% 43%	2340
	11th to 20th	Day	4 3 1 3 2 3 4 4 5% 9% 62%	2340
	21st to end	Day	6% 3 1 3 3 4 4 4 5% 9% 57%	2356
August	1st to 10th	Day	2 2 1 2 3 4 3 2 5% 8% 69%	2149
	11th to 20th	Day	3 3 2 4 3 3 3 4 6% 8% 61%	2123
	21st to end	Day	6% 4 1 5% 4 3 4 4 6% 8% 56%	2376
September	1st to 10th	Day	10% 6% 2 6% 5% 4 5% 4 7% 7% 43%	2013
	11th to 20th	Day	12% 6% 2 6% 4 5% 5% 5% 6% 7% 42%	1980
	21st to end	Day	9% 4 2 5% 3 4 4 4 6% 8% 51%	1980
October	1st to 10th	Day	8% 4 2 4 3 3 4 3 5% 8% 56%	1980
	11th to 20th	Day	14% 6% 2 5% 4 4 3 3 4 7% 49%	1980
	21st to end	Day	13% 5% 1 3 2 2 2 2 3 4 61%	2050
November	1st to 10th	Day	15% 6% 2 6% 3 3 3 2 5% 6% 50%	1755
	11th to 20th	Day	13% 5% 2 4 3 4 4 3 4 6% 52%	1710
	21st to end	Day	15% 7% 2 5% 3 3 3 3 4 5% 50%	1710
December	1st to 10th	Day	17% 7% 3 5% 3 2 2 2 4 5% 49%	1710
	11th to 20th	Day	14% 7% 3 5% 4 4 3 3 4 7% 47%	2161
	21st to end	Day	13% 6% 2 5% 3 3 3 2 4 5% 55%	3135
January	1st to 10th	Night	10% 4 2 4 2 2 2 2 5% 7% 59%	4108
	11th to 20th	Night	9% 4 1 3 2 2 2 2 2 4 69%	3822
	21st to end	Night	16% 6% 2 6% 3 3 2 3 5% 6% 48%	4180
February	1st to 10th	Night	10% 5% 2 4 3 3 3 3 5% 5% 57%	2280
	11th to 20th	Night	14% 6% 1 4 2 2 3 2 4 6% 56%	2218
	21st to end	Night	10% 5% 2 4 3 4 4 3 5% 6% 55%	1884
March	1st to 10th	Night	11% 5% 1 4 3 4 4 4 5% 8% 51%	3706
	11th to 20th	Night	19% 6% 2 6% 4 3 3 3 4 6% 43%	3480
	21st to end	Night	9% 4 2 4 3 3 3 3 5% 7% 58%	3817
April	1st to 10th	Night	9% 4 2 4 3 3 4 4 7% 8% 53%	2014
	11th to 20th	Night	12% 5% 2 5% 4 3 4 3 5% 6% 52%	1877
	21st to end	Night	11% 5% 1 4 2 4 3 3 5% 6% 54%	1900
May	1st to 10th	Night	9% 3 1 5% 4 4 4 5% 7% 7% 51%	1805
	11th to 20th	Night	11% 4 2 5% 4 4 4 4 6% 8% 48%	1620
	21st to end	Night	8% 5% 1 5% 4 4 4 5% 7% 10% 48%	1745
June	1st to 10th	Night	3 2 1 4 3 2 4 3 6% 9% 63%	1620
	11th to 20th	Night	2 1 1 3 3 3 4 4 7% 9% 64%	1620
	21st to end	Night	4 3 1 3 4 5% 5% 4 7% 12% 52%	1620
July	1st to 10th	Night	9% 5% 3 4 4 4 4 4 6% 9% 49%	1620
	11th to 20th	Night	2 2 1 3 3 3 4 4 5% 8% 66%	1620
	21st to end	Night	4 3 1 4 3 2 4 3 6% 9% 61%	1956
August	1st to 10th	Night	2 1 2 2 2 2 2 5% 9% 72%	1790
	11th to 20th	Night	3 3 1 4 3 3 4 3 5% 8% 63%	1778
	21st to end	Night	5% 3 1 4 4 4 4 4 5% 9% 56%	1980
September	1st to 10th	Night	7% 5% 2 6% 4 5% 4 4 7% 9% 47%	1944
	11th to 20th	Night	10% 5% 2 5% 4 4 5% 4 6% 9% 47%	1980
	21st to end	Night	10% 3 2 4 3 4 3 3 5% 8% 53%	1980
October	1st to 10th	Night	7% 4 1 4 2 3 3 2 5% 7% 62%	1980
	11th to 20th	Night	12% 4 2 3 2 2 3 2 4 6% 59%	1980
	21st to end	Night	8% 3 1 3 2 2 2 2 3 4 69%	2286
November	1st to 10th	Night	12% 5% 2 3 3 2 2 2 3 5% 60%	2319
	11th to 20th	Night	10% 5% 2 4 3 2 3 3 4 5% 59%	2470
	21st to end	Night	14% 5% 2 5% 3 3 3 3 5% 5% 51%	2470
December	1st to 10th	Night	14% 5% 1 4 3 3 3 2 4 6% 53%	2470
	11th to 20th	Night	15% 5% 2 5% 3 3 3 2 4 5% 52%	3036
	21st to end	Night	12% 4 2 4 2 3 4 3 4 8% 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 5% 12% 29% 25%	2854
	11th to 20th	Day	27% 3 4 17% 23% 25%	3170
	21st to end	Day	37% 4 9% 14% 27% 9%	3487
February	1st to 10th	Day	35% 4 7% 14% 20% 21%	1900
	11th to 20th	Day	33% 5% 6% 19% 20% 17%	1859
	21st to end	Day	28% 5% 8% 16% 25% 18%	1570
March	1st to 10th	Day	38% 6% 7% 15% 17% 17%	3156
	11th to 20th	Day	47% 4 6% 10% 16% 16%	3480
	21st to end	Day	28% 4 11% 17% 17% 23%	3814
April	1st to 10th	Day	33% 4 8% 18% 19% 18%	2159
	11th to 20th	Day	32% 5% 9% 18% 17% 19%	2254
	21st to end	Day	34% 5% 8% 18% 18% 17%	2280
May	1st to 10th	Day	37% 5% 8% 19% 19% 12%	2373
	11th to 20th	Day	38% 7% 10% 21% 18% 6%	2334
	21st to end	Day	40% 7% 10% 21% 17% 4	2531
June	1st to 10th	Day	20% 6% 13% 30% 23% 7%	2340
	11th to 20th	Day	22% 7% 13% 28% 23% 8%	2340
	21st to end	Day	31% 7% 14% 24% 19% 6%	2340
July	1st to 10th	Day	37% 7% 14% 25% 15% 3	2276
	11th to 20th	Day	18% 7% 14% 33% 24% 5%	2271
	21st to end	Day	20% 7% 17% 37% 17% 2	2225
August	1st to 10th	Day	14% 5% 14% 40% 24% 3	2136
	11th to 20th	Day	20% 7% 18% 33% 19% 4	2123
	21st to end	Day	24% 9% 16% 27% 19% 5%	2376
September	1st to 10th	Day	38% 8% 13% 19% 15% 6%	2013
	11th to 20th	Day	39% 8% 12% 20% 19% 4	1980
	21st to end	Day	29% 7% 11% 23% 18% 11%	1980
October	1st to 10th	Day	28% 6% 9% 23% 23% 10%	1980
	11th to 20th	Day	36% 5% 10% 15% 20% 15%	1980
	21st to end	Day	28% 4 5% 14% 26% 22%	2050
November	1st to 10th	Day	36% 4 8% 19% 21% 12%	1755
	11th to 20th	Day	34% 4 7% 18% 21% 16%	1710
	21st to end	Day	37% 4 7% 17% 18% 17%	1710
December	1st to 10th	Day	39% 4 5% 18% 22% 12%	1710
	11th to 20th	Day	37% 4 8% 16% 17% 19%	2159
	21st to end	Day	33% 3 4 16% 28% 15%	3135
January	1st to 10th	Night	25% 2 6% 13% 28% 25%	4108
	11th to 20th	Night	22% 2 4 18% 25% 30%	3822
	21st to end	Night	38% 4 5% 15% 25% 13%	4180
February	1st to 10th	Night	29% 4 8% 16% 18% 25%	2280
	11th to 20th	Night	32% 4 7% 19% 21% 19%	2218
	21st to end	Night	30% 5% 8% 15% 22% 20%	1884
March	1st to 10th	Night	31% 6% 10% 19% 18% 16%	3706
	11th to 20th	Night	43% 5% 8% 13% 16% 15%	3480
	21st to end	Night	26% 5% 11% 21% 17% 20%	3817
April	1st to 10th	Night	27% 6% 11% 19% 19% 19%	2014
	11th to 20th	Night	32% 6% 9% 17% 16% 20%	1877
	21st to end	Night	31% 5% 10% 21% 18% 15%	1900
May	1st to 10th	Night	30% 7% 13% 21% 17% 13%	1805
	11th to 20th	Night	33% 8% 10% 25% 18% 6%	1621
	21st to end	Night	30% 8% 15% 25% 19% 4	1746
June	1st to 10th	Night	17% 7% 16% 31% 24% 6%	1620
	11th to 20th	Night	17% 6% 14% 29% 27% 8%	1620
	21st to end	Night	24% 8% 16% 26% 20% 6%	1620
July	1st to 10th	Night	32% 8% 18% 23% 16% 3	1575
	11th to 20th	Night	17% 8% 13% 29% 27% 6%	1566
	21st to end	Night	16% 7% 21% 34% 20% 2	1847
August	1st to 10th	Night	12% 4 15% 39% 27% 3	1779
	11th to 20th	Night	19% 8% 16% 33% 20% 4	1778
	21st to end	Night	25% 8% 18% 26% 18% 5%	1980
September	1st to 10th	Night	32% 8% 15% 22% 16% 8%	1944
	11th to 20th	Night	33% 7% 16% 21% 18% 4	1980
	21st to end	Night	29% 5% 12% 23% 18% 13%	1980
October	1st to 10th	Night	23% 5% 11% 26% 23% 13%	1980
	11th to 20th	Night	28% 4 10% 21% 20% 17%	1980
	21st to end	Night	22% 2 7% 16% 28% 24%	2286
November	1st to 10th	Night	29% 2 8% 20% 26% 15%	2319
	11th to 20th	Night	28% 3 9% 20% 22% 17%	2470
	21st to end	Night	34% 5% 8% 17% 19% 18%	2470
December	1st to 10th	Night	33% 4 8% 19% 20% 16%	2470
	11th to 20th	Night	35% 3 7% 16% 20% 19%	3037
	21st to end	Night	30% 5% 8% 15% 24% 19%	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	18% 3 27% 34% 17% 1	270
	11th to 20th	Day	19% 7% 23% 33% 17% 1	270
	21st to end	Day	12% 10% 29% 33% 14% 2	297
February	1st to 10th	Day	20% 8% 23% 26% 18% 5%	270
	11th to 20th	Day	20% 8% 33% 24% 12% 3	270
	21st to end	Day	15% 10% 34% 28% 12%	225
March	1st to 10th	Day	17% 10% 34% 33% 5% 1	270
	11th to 20th	Day	17% 9% 33% 28% 13%	270
	21st to end	Day	13% 12% 32% 34% 9%	297
April	1st to 10th	Day	11% 11% 37% 33% 8%	339
	11th to 20th	Day	9% 12% 40% 32% 7%	452
	21st to end	Day	11% 8% 39% 33% 7% 1	460
May	1st to 10th	Day	14% 7% 33% 34% 10% 1	556
	11th to 20th	Day	14% 6% 30% 37% 12% 1	637
	21st to end	Day	15% 5% 24% 41% 14% 1	679
June	1st to 10th	Day	4 2 15% 51% 24% 4	630
	11th to 20th	Day	4 1 14% 50% 26% 5%	630
	21st to end	Day	3 2 9% 42% 37% 7%	630
July	1st to 10th	Day	11% 1 5% 32% 43% 8%	621
	11th to 20th	Day	3 3 35% 50% 8%	618
	21st to end	Day	3 4 35% 47% 11%	494
August	1st to 10th	Day	2 3 31% 50% 14%	447
	11th to 20th	Day	3 5% 28% 46% 18%	437
	21st to end	Day	4 1 4 31% 42% 18%	495
September	1st to 10th	Day	12% 1 23% 41% 23%	303
	11th to 20th	Day	6% 1 4 15% 40% 33%	270
	21st to end	Day	7% 1 6% 18% 46% 22%	270
October	1st to 10th	Day	10% 2 10% 27% 40% 12%	270
	11th to 20th	Day	14% 1 8% 37% 32% 8%	270
	21st to end	Day	18% 7% 20% 31% 19% 5%	297
November	1st to 10th	Day	21% 5% 17% 27% 24% 6%	270
	11th to 20th	Day	23% 6% 11% 26% 25% 9%	270
	21st to end	Day	20% 6% 28% 29% 14% 3	270
December	1st to 10th	Day	22% 5% 18% 28% 19% 8%	270
	11th to 20th	Day	16% 10% 26% 25% 22% 1	270
	21st to end	Day	16% 5% 26% 29% 21% 3	297
January	1st to 10th	Night	15% 3 21% 46% 14% 1	950
	11th to 20th	Night	16% 4 19% 51% 11%	769
	21st to end	Night	17% 6% 23% 44% 9%	836
February	1st to 10th	Night	14% 6% 26% 43% 11%	760
	11th to 20th	Night	16% 7% 30% 40% 7%	744
	21st to end	Night	14% 6% 32% 44% 4	628
March	1st to 10th	Night	16% 7% 33% 37% 7%	745
	11th to 20th	Night	12% 9% 34% 40% 5%	570
	21st to end	Night	10% 7% 47% 31% 5%	627
April	1st to 10th	Night	9% 6% 43% 39% 3	570
	11th to 20th	Night	13% 7% 45% 32% 3	563
	21st to end	Night	12% 7% 46% 31% 4	570
May	1st to 10th	Night	8% 6% 45% 37% 3	570
	11th to 20th	Night	11% 6% 41% 36% 6%	540
	21st to end	Night	8% 5% 38% 39% 10%	584
June	1st to 10th	Night	3 2 25% 59% 10%	540
	11th to 20th	Night	2 1 29% 58% 10% 1	540
	21st to end	Night	4 1 17% 60% 18%	540
July	1st to 10th	Night	9% 1 11% 59% 18% 1	525
	11th to 20th	Night	2 1 8% 63% 25% 1	522
	21st to end	Night	4 1 10% 58% 27% 1	591
August	1st to 10th	Night	2 7% 61% 28% 2	537
	11th to 20th	Night	4 1 8% 50% 35% 1	534
	21st to end	Night	4 1 7% 52% 33% 3	594
September	1st to 10th	Night	8% 1 5% 45% 36% 4	540
	11th to 20th	Night	11% 2 4 42% 38% 3	540
	21st to end	Night	11% 1 8% 40% 36% 4	540
October	1st to 10th	Night	7% 1 9% 47% 34% 1	540
	11th to 20th	Night	13% 1 16% 41% 27% 1	540
	21st to end	Night	9% 5% 18% 42% 24% 2	702
November	1st to 10th	Night	15% 3 12% 40% 28% 1	839
	11th to 20th	Night	13% 3 16% 42% 24% 2	950
	21st to end	Night	17% 5% 17% 43% 17% 1	950
December	1st to 10th	Night	17% 2 17% 43% 21% 1	950
	11th to 20th	Night	21% 5% 18% 41% 15%	950
	21st to end	Night	15% 5% 20% 45% 14% 1	1045

Page generated at 2024-05-10 11:39:00. Version ac07

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