Anahuac Wildlife Refuge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Anahuac Wildlife Refuge clear sky chart from 2005-11-06 to 2026-10-29.

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% 6% 2 6% 4 5% 5% 4 6% 9% 40%	148674
	Night	13% 6% 2 6% 4 4 4 3 5% 8% 45%	143709
Transparency	Day	37% 9% 15% 20% 14% 6%	152294
	Night	36% 7% 14% 20% 16% 8%	148156
Seeing	Day	11% 6% 20% 28% 24% 9%	17457
	Night	13% 6% 19% 30% 26% 6%	27194

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	17% 9% 3 8% 3 3 3 3 4 5% 42%	5289
	11th to 20th	Day	13% 7% 2 6% 4 4 4 3 3 5% 49%	5310
	21st to end	Day	24% 9% 4 9% 4 3 4 3 4 6% 31%	5812
February	1st to 10th	Day	19% 8% 3 7% 5% 4 4 4 5% 6% 36%	1911
	11th to 20th	Day	22% 9% 3 6% 4 3 3 3 4 5% 38%	2157
	21st to end	Day	21% 8% 3 7% 4 3 4 4 3 6% 37%	1903
March	1st to 10th	Day	18% 8% 3 8% 5% 4 5% 4 6% 7% 33%	5046
	11th to 20th	Day	15% 7% 3 7% 4 4 4 3 5% 6% 44%	5090
	21st to end	Day	17% 7% 3 6% 4 4 4 3 5% 6% 40%	5583
April	1st to 10th	Day	14% 7% 3 7% 4 4 5% 4 6% 7% 38%	2325
	11th to 20th	Day	14% 7% 3 6% 5% 5% 4 4 6% 9% 37%	2494
	21st to end	Day	9% 7% 2 6% 4 4 5% 4 6% 8% 44%	2520
May	1st to 10th	Day	19% 8% 3 9% 6% 5% 5% 4 6% 7% 27%	7021
	11th to 20th	Day	10% 6% 3 7% 5% 5% 5% 4 6% 9% 40%	7385
	21st to end	Day	8% 6% 3 8% 6% 6% 7% 6% 10% 12% 29%	8392
June	1st to 10th	Day	6% 5% 2 6% 4 6% 6% 6% 8% 12% 40%	2730
	11th to 20th	Day	5% 4 2 7% 5% 5% 7% 6% 8% 12% 38%	2730
	21st to end	Day	7% 5% 2 6% 5% 6% 7% 8% 9% 12% 33%	2730
July	1st to 10th	Day	5% 4 2 5% 5% 5% 6% 5% 9% 14% 39%	7680
	11th to 20th	Day	7% 6% 3 9% 6% 7% 7% 6% 8% 11% 31%	7680
	21st to end	Day	7% 6% 2 6% 4 5% 5% 4 7% 11% 44%	8337
August	1st to 10th	Day	1 2 1 2 3 3 5% 5% 8% 13% 56%	6014
	11th to 20th	Day	2 1 1 3 3 3 5% 5% 8% 13% 57%	5514
	21st to end	Day	6% 4 2 6% 5% 5% 6% 5% 8% 12% 42%	6080
September	1st to 10th	Day	9% 6% 3 8% 5% 5% 7% 5% 9% 10% 33%	2392
	11th to 20th	Day	13% 6% 2 6% 4 5% 5% 5% 7% 9% 38%	2310
	21st to end	Day	9% 4 2 5% 4 4 5% 4 7% 9% 46%	2310
October	1st to 10th	Day	6% 4 2 5% 3 4 4 3 7% 7% 55%	2122
	11th to 20th	Day	9% 4 1 4 3 4 4 3 7% 7% 55%	2100
	21st to end	Day	11% 5% 2 5% 3 3 3 3 4 7% 54%	2280
November	1st to 10th	Day	10% 5% 2 5% 5% 4 4 3 5% 8% 48%	2058
	11th to 20th	Day	12% 5% 1 5% 4 5% 4 4 5% 7% 48%	2100
	21st to end	Day	14% 8% 3 6% 4 3 4 4 4 6% 44%	2100
December	1st to 10th	Day	21% 10% 2 7% 4 3 3 3 4 7% 37%	3101
	11th to 20th	Day	11% 7% 3 7% 5% 5% 5% 4 5% 7% 42%	3481
	21st to end	Day	13% 7% 2 6% 4 4 4 3 4 6% 46%	4587
January	1st to 10th	Night	16% 6% 3 6% 4 4 3 3 4 5% 46%	7634
	11th to 20th	Night	14% 7% 2 6% 4 3 4 3 4 5% 47%	7680
	21st to end	Night	27% 9% 3 6% 4 4 3 3 4 7% 30%	8402
February	1st to 10th	Night	18% 8% 3 6% 4 3 3 3 4 6% 41%	2725
	11th to 20th	Night	18% 9% 4 7% 4 3 3 3 4 5% 41%	2348
	21st to end	Night	19% 9% 3 6% 3 4 3 3 4 6% 39%	1903
March	1st to 10th	Night	21% 10% 3 7% 4 3 4 2 5% 6% 36%	5029
	11th to 20th	Night	17% 9% 3 6% 4 3 3 3 4 5% 43%	5090
	21st to end	Night	16% 10% 2 6% 4 3 3 3 4 6% 42%	5588
April	1st to 10th	Night	15% 7% 3 6% 4 5% 4 5% 6% 7% 40%	2294
	11th to 20th	Night	15% 6% 3 5% 3 3 3 4 5% 7% 46%	2075
	21st to end	Night	13% 5% 3 5% 4 5% 5% 4 7% 8% 43%	2100
May	1st to 10th	Night	24% 9% 3 7% 5% 4 4 4 5% 8% 27%	5832
	11th to 20th	Night	13% 6% 2 7% 5% 4 5% 4 6% 8% 40%	5477
	21st to end	Night	12% 8% 3 7% 5% 5% 5% 4 8% 12% 31%	5793
June	1st to 10th	Night	4 4 1 4 3 4 5% 4 7% 11% 53%	1890
	11th to 20th	Night	6% 3 1 5% 4 3 5% 4 7% 13% 49%	1890
	21st to end	Night	6% 5% 2 6% 4 5% 5% 5% 9% 12% 41%	1890
July	1st to 10th	Night	3 4 2 5% 4 4 4 3 7% 13% 51%	5308
	11th to 20th	Night	5% 5% 2 7% 6% 6% 6% 5% 7% 10% 40%	5307
	21st to end	Night	5% 4 2 6% 4 4 5% 4 8% 12% 47%	5770
August	1st to 10th	Night	1 1 1 2 2 2 3 3 5% 10% 72%	4156
	11th to 20th	Night	1 1 1 3 2 2 3 3 7% 11% 65%	4529
	21st to end	Night	3 3 1 5% 3 4 5% 5% 8% 14% 49%	5046
September	1st to 10th	Night	6% 5% 2 6% 4 5% 5% 5% 8% 12% 42%	2221
	11th to 20th	Night	9% 6% 2 6% 3 5% 5% 4 6% 8% 44%	2310
	21st to end	Night	7% 4 2 5% 3 4 4 4 6% 8% 53%	2310
October	1st to 10th	Night	6% 4 1 4 3 4 4 3 5% 8% 59%	2474
	11th to 20th	Night	8% 3 1 3 3 3 4 3 5% 7% 60%	2520
	21st to end	Night	10% 5% 2 4 3 3 3 3 4 5% 59%	2737
November	1st to 10th	Night	9% 6% 2 5% 3 3 3 4 5% 7% 53%	2460
	11th to 20th	Night	11% 5% 1 5% 3 3 4 3 4 6% 55%	2520
	21st to end	Night	13% 6% 3 6% 4 4 4 3 5% 6% 46%	2520
December	1st to 10th	Night	23% 9% 4 7% 5% 4 3 3 5% 6% 32%	4302
	11th to 20th	Night	12% 7% 3 8% 5% 4 4 3 5% 6% 44%	4946
	21st to end	Night	15% 7% 3 6% 4 3 4 2 4 6% 46%	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	45% 6% 7% 20% 17% 6%	5290
	11th to 20th	Day	36% 5% 8% 19% 20% 12%	5310
	21st to end	Day	54% 5% 5% 13% 14% 10%	5812
February	1st to 10th	Day	48% 6% 6% 15% 15% 10%	1911
	11th to 20th	Day	49% 5% 10% 14% 15% 8%	2167
	21st to end	Day	48% 7% 8% 14% 16% 8%	1903
March	1st to 10th	Day	47% 10% 8% 13% 12% 10%	5046
	11th to 20th	Day	40% 8% 8% 12% 18% 15%	5090
	21st to end	Day	42% 7% 10% 19% 19% 2	5585
April	1st to 10th	Day	44% 8% 10% 15% 14% 8%	2325
	11th to 20th	Day	43% 7% 12% 16% 14% 8%	2494
	21st to end	Day	35% 9% 13% 20% 18% 5%	2520
May	1st to 10th	Day	51% 11% 11% 15% 10% 2	7056
	11th to 20th	Day	37% 9% 15% 20% 16% 3	7389
	21st to end	Day	39% 13% 20% 22% 6%	8405
June	1st to 10th	Day	32% 12% 18% 25% 13%	2730
	11th to 20th	Day	33% 10% 19% 25% 11% 1	2730
	21st to end	Day	36% 14% 19% 24% 7%	2730
July	1st to 10th	Day	30% 12% 36% 20% 1	7616
	11th to 20th	Day	43% 12% 27% 16% 3	7611
	21st to end	Day	32% 11% 20% 33% 4	8155
August	1st to 10th	Day	15% 10% 25% 33% 14% 3	6000
	11th to 20th	Day	16% 10% 36% 33% 4	5550
	21st to end	Day	32% 10% 17% 28% 11% 1	6079
September	1st to 10th	Day	40% 15% 16% 14% 13% 3	2392
	11th to 20th	Day	40% 10% 14% 21% 13% 2	2310
	21st to end	Day	31% 9% 15% 22% 13% 9%	2310
October	1st to 10th	Day	21% 5% 8% 16% 16% 34%	3395
	11th to 20th	Day	19% 5% 8% 19% 39% 10%	3340
	21st to end	Day	24% 5% 8% 17% 37% 10%	3618
November	1st to 10th	Day	33% 7% 11% 21% 19% 9%	2058
	11th to 20th	Day	34% 7% 11% 16% 20% 13%	2100
	21st to end	Day	41% 6% 10% 17% 19% 8%	2100
December	1st to 10th	Day	48% 4 8% 16% 19% 5%	3101
	11th to 20th	Day	39% 9% 9% 16% 18% 10%	3479
	21st to end	Day	38% 6% 8% 16% 21% 11%	4587
January	1st to 10th	Night	40% 5% 10% 19% 18% 8%	7635
	11th to 20th	Night	39% 5% 5% 16% 23% 13%	7680
	21st to end	Night	54% 4 6% 12% 16% 8%	8402
February	1st to 10th	Night	46% 5% 8% 11% 20% 11%	2725
	11th to 20th	Night	45% 6% 7% 14% 18% 10%	2348
	21st to end	Night	46% 6% 7% 14% 17% 10%	1903
March	1st to 10th	Night	47% 7% 8% 14% 14% 10%	5029
	11th to 20th	Night	43% 7% 7% 12% 15% 16%	5090
	21st to end	Night	42% 7% 8% 16% 20% 7%	5588
April	1st to 10th	Night	42% 8% 10% 16% 15% 9%	2294
	11th to 20th	Night	36% 6% 12% 19% 15% 12%	2075
	21st to end	Night	36% 8% 13% 19% 18% 6%	2100
May	1st to 10th	Night	54% 8% 11% 16% 10% 3	5862
	11th to 20th	Night	39% 8% 12% 22% 15% 3	5478
	21st to end	Night	40% 13% 21% 21% 6%	5805
June	1st to 10th	Night	22% 10% 21% 32% 14%	1890
	11th to 20th	Night	25% 10% 20% 30% 15% 1	1890
	21st to end	Night	31% 10% 26% 26% 8%	1890
July	1st to 10th	Night	25% 8% 43% 22% 2	5265
	11th to 20th	Night	36% 10% 33% 18% 4	5256
	21st to end	Night	29% 10% 20% 36% 5%	5641
August	1st to 10th	Night	10% 6% 28% 40% 15% 2	4146
	11th to 20th	Night	12% 6% 39% 37% 5%	4559
	21st to end	Night	24% 12% 21% 32% 9% 1	5046
September	1st to 10th	Night	32% 12% 22% 18% 12% 3	2221
	11th to 20th	Night	35% 9% 17% 20% 15% 3	2310
	21st to end	Night	28% 8% 16% 23% 18% 8%	2310
October	1st to 10th	Night	18% 6% 8% 17% 17% 34%	3968
	11th to 20th	Night	15% 5% 7% 24% 30% 18%	4019
	21st to end	Night	19% 5% 7% 14% 39% 16%	4349
November	1st to 10th	Night	30% 6% 12% 21% 21% 10%	2460
	11th to 20th	Night	30% 5% 10% 20% 22% 12%	2520
	21st to end	Night	39% 5% 10% 19% 18% 8%	2520
December	1st to 10th	Night	53% 5% 7% 15% 15% 5%	4302
	11th to 20th	Night	40% 6% 8% 14% 18% 13%	4947
	21st to end	Night	39% 6% 7% 14% 26% 8%	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	25% 12% 36% 21% 6%	330
	11th to 20th	Day	15% 14% 35% 28% 7% 1	330
	21st to end	Day	21% 18% 34% 23% 4	363
February	1st to 10th	Day	21% 14% 37% 23% 5%	330
	11th to 20th	Day	25% 16% 34% 21% 3	330
	21st to end	Day	18% 18% 42% 19% 3	273
March	1st to 10th	Day	19% 14% 40% 24% 3	330
	11th to 20th	Day	13% 18% 48% 14% 6% 1	330
	21st to end	Day	16% 15% 33% 26% 8% 1	363
April	1st to 10th	Day	15% 17% 37% 25% 6%	345
	11th to 20th	Day	17% 13% 33% 24% 12%	532
	21st to end	Day	12% 8% 35% 31% 12% 1	540
May	1st to 10th	Day	14% 11% 33% 26% 16% 1	543
	11th to 20th	Day	10% 6% 26% 39% 16% 3	687
	21st to end	Day	7% 5% 24% 40% 21% 3	844
June	1st to 10th	Day	6% 3 15% 37% 29% 9%	780
	11th to 20th	Day	7% 2 14% 39% 29% 10%	780
	21st to end	Day	9% 1 9% 34% 33% 13%	780
July	1st to 10th	Day	6% 2 5% 27% 40% 20%	771
	11th to 20th	Day	7% 2 3 26% 42% 20%	768
	21st to end	Day	6% 1 4 30% 40% 19%	849
August	1st to 10th	Day	3 1 2 20% 49% 25%	776
	11th to 20th	Day	3 1 2 13% 51% 30%	574
	21st to end	Day	11% 2 6% 18% 38% 26%	627
September	1st to 10th	Day	10% 2 8% 23% 38% 18%	442
	11th to 20th	Day	9% 1 6% 26% 42% 17%	360
	21st to end	Day	10% 10% 29% 39% 11%	360
October	1st to 10th	Day	8% 2 9% 42% 32% 8%	360
	11th to 20th	Day	9% 2 16% 37% 29% 7%	360
	21st to end	Day	14% 8% 21% 33% 19% 4	387
November	1st to 10th	Day	12% 6% 22% 36% 20% 4	330
	11th to 20th	Day	14% 5% 25% 41% 12% 2	330
	21st to end	Day	15% 14% 33% 25% 10% 3	330
December	1st to 10th	Day	18% 10% 33% 24% 12% 4	330
	11th to 20th	Day	16% 13% 34% 28% 9% 1	330
	21st to end	Day	16% 12% 36% 27% 8% 1	363
January	1st to 10th	Night	21% 9% 32% 29% 9%	1050
	11th to 20th	Night	18% 9% 30% 33% 10%	1050
	21st to end	Night	22% 9% 28% 34% 7%	1155
February	1st to 10th	Night	22% 8% 30% 33% 6%	1045
	11th to 20th	Night	22% 11% 28% 30% 9%	714
	21st to end	Night	21% 12% 33% 27% 7%	519
March	1st to 10th	Night	22% 9% 30% 30% 9%	630
	11th to 20th	Night	17% 10% 27% 36% 10% 1	630
	21st to end	Night	15% 8% 26% 34% 17% 1	693
April	1st to 10th	Night	16% 7% 30% 35% 11%	630
	11th to 20th	Night	17% 10% 27% 34% 13%	623
	21st to end	Night	14% 7% 27% 37% 14% 1	630
May	1st to 10th	Night	15% 8% 25% 39% 13%	630
	11th to 20th	Night	9% 6% 22% 42% 20% 1	621
	21st to end	Night	5% 5% 19% 37% 31% 4	683
June	1st to 10th	Night	6% 2 5% 34% 46% 6%	630
	11th to 20th	Night	7% 2 6% 34% 45% 7%	630
	21st to end	Night	7% 1 5% 24% 47% 14%	630
July	1st to 10th	Night	6% 1 4 19% 48% 22%	615
	11th to 20th	Night	4 1 2 13% 55% 26%	612
	21st to end	Night	4 1 3 16% 59% 18%	690
August	1st to 10th	Night	2 1 9% 63% 25%	627
	11th to 20th	Night	4 2 7% 65% 22%	624
	21st to end	Night	7% 1 4 17% 51% 20%	693
September	1st to 10th	Night	7% 2 6% 16% 50% 20%	630
	11th to 20th	Night	10% 2 6% 19% 50% 13%	630
	21st to end	Night	9% 2 5% 26% 49% 9%	630
October	1st to 10th	Night	6% 2 9% 33% 41% 9%	794
	11th to 20th	Night	8% 2 15% 38% 32% 5%	840
	21st to end	Night	10% 7% 17% 36% 26% 3	913
November	1st to 10th	Night	10% 4 17% 39% 25% 4	820
	11th to 20th	Night	13% 5% 19% 41% 21% 1	840
	21st to end	Night	15% 7% 27% 34% 15% 2	840
December	1st to 10th	Night	21% 7% 23% 32% 16% 1	998
	11th to 20th	Night	19% 8% 27% 33% 12%	1050
	21st to end	Night	20% 9% 28% 32% 11%	1155

Page generated at 2026-10-26 03:37:47. Version ac07

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