Lufkin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lufkin clear sky chart from 2005-11-06 to 2026-01-17.

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% 6% 2 6% 4 4 4 4 6% 8% 43%	127293
	Night	13% 6% 2 5% 4 3 4 3 5% 7% 47%	124641
Transparency	Day	38% 5% 11% 21% 18% 7%	130916
	Night	36% 4 10% 20% 20% 9%	129081
Seeing	Day	14% 8% 22% 26% 22% 7%	16574
	Night	16% 7% 24% 33% 18% 2	26474

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	19% 8% 3 6% 4 3 3 3 4 5% 43%	4167
	11th to 20th	Day	16% 5% 2 4 3 2 3 2 5% 6% 52%	4134
	21st to end	Day	27% 10% 3 5% 2 2 2 2 3 4 41%	4488
February	1st to 10th	Day	21% 8% 3 7% 5% 3 4 3 3 4 38%	1800
	11th to 20th	Day	23% 9% 2 5% 5% 3 3 2 3 5% 39%	1978
	21st to end	Day	22% 8% 4 6% 3 3 4 2 4 5% 40%	1815
March	1st to 10th	Day	19% 11% 3 8% 4 4 3 3 4 5% 37%	4936
	11th to 20th	Day	14% 5% 2 5% 4 4 4 3 5% 6% 48%	4980
	21st to end	Day	17% 9% 3 7% 4 4 4 3 5% 7% 39%	5462
April	1st to 10th	Day	14% 9% 3 7% 5% 4 4 4 5% 6% 40%	2223
	11th to 20th	Day	14% 8% 2 6% 4 4 5% 4 5% 7% 40%	2374
	21st to end	Day	11% 6% 2 6% 6% 4 4 4 5% 7% 44%	2400
May	1st to 10th	Day	17% 8% 3 7% 5% 4 5% 4 6% 7% 32%	5493
	11th to 20th	Day	13% 6% 3 6% 5% 5% 5% 4 6% 8% 40%	5862
	21st to end	Day	10% 7% 3 7% 5% 5% 5% 5% 7% 11% 35%	6434
June	1st to 10th	Day	7% 4 2 7% 6% 5% 6% 5% 8% 11% 39%	2600
	11th to 20th	Day	5% 4 2 6% 5% 5% 7% 6% 8% 11% 41%	2600
	21st to end	Day	6% 6% 2 7% 5% 6% 6% 5% 8% 11% 38%	2600
July	1st to 10th	Day	9% 6% 2 6% 5% 5% 6% 6% 8% 12% 36%	5900
	11th to 20th	Day	6% 5% 2 6% 4 5% 5% 5% 8% 11% 43%	5900
	21st to end	Day	11% 7% 3 7% 4 4 5% 4 7% 8% 40%	6422
August	1st to 10th	Day	2 2 1 3 3 3 4 3 5% 9% 66%	4234
	11th to 20th	Day	3 3 1 4 3 3 4 3 8% 11% 57%	3979
	21st to end	Day	8% 4 2 6% 5% 6% 6% 5% 8% 11% 38%	4312
September	1st to 10th	Day	6% 5% 3 7% 5% 5% 5% 4 8% 8% 44%	2290
	11th to 20th	Day	12% 5% 2 6% 5% 4 5% 4 6% 8% 43%	2200
	21st to end	Day	7% 5% 1 5% 4 4 4 4 8% 8% 51%	2200
October	1st to 10th	Day	7% 4 2 4 3 3 4 2 4 6% 62%	2025
	11th to 20th	Day	11% 6% 1 4 3 3 3 3 4 6% 56%	2000
	21st to end	Day	14% 6% 2 5% 2 3 3 3 4 6% 53%	2200
November	1st to 10th	Day	11% 7% 2 5% 4 4 5% 3 6% 6% 48%	2058
	11th to 20th	Day	12% 6% 2 5% 4 3 3 3 4 6% 52%	2100
	21st to end	Day	17% 7% 2 6% 4 3 3 3 4 5% 45%	2029
December	1st to 10th	Day	22% 6% 2 5% 3 3 4 3 4 4 46%	3030
	11th to 20th	Day	17% 8% 3 6% 5% 4 3 3 4 6% 41%	3481
	21st to end	Day	16% 9% 3 7% 3 3 3 3 3 5% 44%	4587
January	1st to 10th	Night	17% 6% 2 5% 3 3 3 3 3 5% 51%	6018
	11th to 20th	Night	15% 6% 2 5% 3 2 3 2 3 4 54%	5979
	21st to end	Night	27% 11% 2 5% 2 2 3 2 3 5% 37%	6490
February	1st to 10th	Night	18% 8% 3 5% 4 3 3 3 4 6% 43%	2600
	11th to 20th	Night	22% 8% 3 6% 3 3 4 2 2 4 43%	2327
	21st to end	Night	21% 6% 2 5% 4 3 3 3 4 5% 43%	1815
March	1st to 10th	Night	22% 9% 2 5% 3 3 3 2 3 6% 41%	4919
	11th to 20th	Night	14% 6% 1 6% 4 3 3 3 5% 6% 49%	4980
	21st to end	Night	19% 8% 3 7% 4 4 3 3 4 4 42%	5467
April	1st to 10th	Night	12% 7% 2 6% 4 4 4 4 5% 7% 44%	2175
	11th to 20th	Night	13% 6% 2 6% 4 4 4 3 5% 7% 45%	1975
	21st to end	Night	13% 7% 2 6% 4 3 4 3 4 6% 48%	2000
May	1st to 10th	Night	15% 10% 3 8% 5% 4 4 3 6% 8% 33%	4388
	11th to 20th	Night	12% 7% 3 7% 5% 5% 5% 4 6% 6% 40%	4053
	21st to end	Night	10% 6% 2 7% 5% 5% 4 6% 7% 10% 38%	4443
June	1st to 10th	Night	6% 4 1 5% 3 3 4 4 7% 11% 50%	1800
	11th to 20th	Night	3 3 1 4 3 3 3 4 7% 12% 56%	1800
	21st to end	Night	6% 4 2 5% 5% 4 5% 4 7% 12% 47%	1800
July	1st to 10th	Night	7% 4 2 7% 5% 5% 6% 5% 8% 13% 38%	4078
	11th to 20th	Night	3 4 2 5% 4 4 5% 4 8% 12% 50%	4077
	21st to end	Night	10% 6% 2 6% 3 4 4 4 6% 10% 45%	4449
August	1st to 10th	Night	2 1 1 2 1 2 2 3 4 9% 73%	2926
	11th to 20th	Night	3 2 1 3 2 3 4 4 7% 13% 58%	3071
	21st to end	Night	5% 4 2 7% 5% 5% 6% 5% 7% 10% 44%	3586
September	1st to 10th	Night	6% 5% 3 6% 4 5% 4 4 5% 6% 52%	2105
	11th to 20th	Night	10% 7% 2 7% 4 3 5% 3 5% 8% 48%	2200
	21st to end	Night	7% 4 2 4 3 3 4 4 7% 7% 56%	2200
October	1st to 10th	Night	4 3 1 3 3 4 4 4 4 7% 63%	2354
	11th to 20th	Night	9% 5% 1 4 2 3 3 3 5% 5% 60%	2400
	21st to end	Night	13% 4 2 3 2 2 3 2 4 5% 59%	2640
November	1st to 10th	Night	13% 5% 2 4 3 3 3 3 4 6% 54%	2460
	11th to 20th	Night	10% 6% 2 5% 3 3 3 3 3 6% 55%	2520
	21st to end	Night	17% 7% 2 6% 3 3 3 3 5% 6% 47%	2587
December	1st to 10th	Night	21% 8% 2 6% 4 3 3 2 4 5% 43%	4380
	11th to 20th	Night	17% 9% 2 6% 4 3 3 3 4 5% 44%	4946
	21st to end	Night	16% 7% 2 5% 3 3 3 2 4 5% 51%	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	44% 4 4 24% 21% 4	4168
	11th to 20th	Day	34% 2 4 21% 28% 11%	4134
	21st to end	Day	50% 2 2 15% 17% 14%	4488
February	1st to 10th	Day	51% 4 5% 13% 19% 10%	1800
	11th to 20th	Day	51% 3 6% 15% 17% 8%	1988
	21st to end	Day	49% 4 6% 13% 18% 11%	1815
March	1st to 10th	Day	51% 3 5% 11% 19% 11%	4936
	11th to 20th	Day	37% 4 5% 16% 21% 17%	4980
	21st to end	Day	45% 4 9% 20% 17% 5%	5464
April	1st to 10th	Day	44% 6% 7% 18% 17% 8%	2223
	11th to 20th	Day	42% 5% 11% 15% 18% 8%	2374
	21st to end	Day	39% 5% 9% 19% 23% 5%	2400
May	1st to 10th	Day	50% 5% 11% 21% 10% 2	5528
	11th to 20th	Day	42% 5% 15% 16% 21% 1	5866
	21st to end	Day	41% 7% 13% 22% 15% 2	6447
June	1st to 10th	Day	36% 9% 16% 23% 15% 1	2600
	11th to 20th	Day	34% 8% 14% 26% 16% 2	2600
	21st to end	Day	38% 9% 15% 23% 13% 2	2600
July	1st to 10th	Day	40% 6% 28% 22% 4	5836
	11th to 20th	Day	33% 6% 21% 32% 8%	5831
	21st to end	Day	40% 7% 15% 28% 10%	6240
August	1st to 10th	Day	16% 6% 14% 35% 28% 1	4220
	11th to 20th	Day	20% 6% 25% 39% 9% 1	4018
	21st to end	Day	37% 9% 19% 20% 14% 1	4311
September	1st to 10th	Day	35% 8% 14% 19% 16% 8%	2290
	11th to 20th	Day	38% 7% 13% 19% 17% 6%	2200
	21st to end	Day	29% 6% 11% 22% 20% 12%	2200
October	1st to 10th	Day	16% 3 6% 13% 25% 37%	3298
	11th to 20th	Day	20% 3 3 22% 30% 22%	3240
	21st to end	Day	28% 3 4 14% 38% 13%	3538
November	1st to 10th	Day	36% 5% 8% 18% 23% 10%	2058
	11th to 20th	Day	35% 3 6% 19% 24% 12%	2100
	21st to end	Day	42% 4 6% 19% 21% 8%	2029
December	1st to 10th	Day	43% 2 7% 16% 25% 6%	3030
	11th to 20th	Day	45% 3 6% 14% 23% 10%	3479
	21st to end	Day	44% 3 5% 14% 28% 6%	4587
January	1st to 10th	Night	38% 3 4 24% 25% 6%	6018
	11th to 20th	Night	36% 2 4 17% 31% 10%	5979
	21st to end	Night	53% 2 4 12% 16% 13%	6490
February	1st to 10th	Night	44% 4 5% 15% 18% 14%	2600
	11th to 20th	Night	48% 3 5% 15% 19% 10%	2327
	21st to end	Night	44% 4 8% 13% 16% 15%	1815
March	1st to 10th	Night	47% 3 5% 12% 21% 12%	4919
	11th to 20th	Night	38% 4 6% 15% 17% 20%	4980
	21st to end	Night	47% 4 7% 15% 20% 7%	5467
April	1st to 10th	Night	39% 5% 9% 19% 16% 12%	2175
	11th to 20th	Night	38% 6% 9% 19% 16% 12%	1975
	21st to end	Night	37% 5% 10% 18% 24% 6%	2000
May	1st to 10th	Night	48% 6% 10% 21% 13% 3	4418
	11th to 20th	Night	44% 4 12% 17% 20% 2	4054
	21st to end	Night	38% 6% 16% 25% 12% 2	4452
June	1st to 10th	Night	26% 7% 19% 29% 18% 1	1800
	11th to 20th	Night	21% 7% 18% 32% 18% 4	1800
	21st to end	Night	29% 8% 17% 29% 16% 1	1800
July	1st to 10th	Night	36% 8% 30% 21% 4	4035
	11th to 20th	Night	26% 7% 27% 31% 8%	4026
	21st to end	Night	36% 7% 19% 28% 10% 1	4320
August	1st to 10th	Night	10% 5% 17% 34% 32% 2	2916
	11th to 20th	Night	17% 6% 24% 43% 9% 1	3098
	21st to end	Night	33% 10% 18% 22% 15% 2	3586
September	1st to 10th	Night	31% 7% 16% 20% 17% 9%	2105
	11th to 20th	Night	35% 6% 13% 22% 17% 7%	2200
	21st to end	Night	24% 6% 11% 23% 22% 13%	2200
October	1st to 10th	Night	14% 4 5% 15% 21% 41%	3848
	11th to 20th	Night	16% 2 4 21% 32% 25%	3899
	21st to end	Night	24% 2 4 15% 39% 15%	4252
November	1st to 10th	Night	33% 4 9% 19% 24% 12%	2460
	11th to 20th	Night	33% 3 7% 20% 24% 14%	2520
	21st to end	Night	39% 3 8% 17% 22% 10%	2587
December	1st to 10th	Night	46% 3 5% 15% 26% 5%	4380
	11th to 20th	Night	45% 3 6% 12% 23% 12%	4947
	21st to end	Night	38% 3 6% 15% 31% 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	24% 15% 39% 17% 5%	330
	11th to 20th	Day	27% 13% 36% 20% 4 1	318
	21st to end	Day	28% 20% 33% 16% 3	330
February	1st to 10th	Day	28% 17% 37% 15% 3	300
	11th to 20th	Day	37% 15% 32% 15% 1	300
	21st to end	Day	27% 22% 38% 9% 3	249
March	1st to 10th	Day	27% 19% 35% 13% 5%	300
	11th to 20th	Day	22% 23% 40% 14% 2 1	300
	21st to end	Day	22% 13% 43% 18% 2 1	330
April	1st to 10th	Day	23% 18% 37% 19% 3 1	323
	11th to 20th	Day	24% 15% 30% 22% 10%	492
	21st to end	Day	16% 13% 35% 26% 9% 2	500
May	1st to 10th	Day	17% 11% 35% 29% 8%	539
	11th to 20th	Day	15% 9% 28% 30% 17% 2	725
	21st to end	Day	11% 7% 28% 32% 17% 5%	789
June	1st to 10th	Day	7% 3 17% 35% 30% 8%	730
	11th to 20th	Day	6% 2 18% 38% 30% 6%	730
	21st to end	Day	8% 3 13% 29% 35% 13%	730
July	1st to 10th	Day	9% 2 9% 28% 38% 15%	721
	11th to 20th	Day	5% 1 5% 29% 46% 14%	718
	21st to end	Day	6% 2 6% 27% 44% 15%	794
August	1st to 10th	Day	4 1 4 25% 47% 18%	726
	11th to 20th	Day	6% 1 2 24% 47% 21%	601
	21st to end	Day	12% 3 5% 20% 38% 21%	583
September	1st to 10th	Day	5% 1 9% 29% 40% 16%	420
	11th to 20th	Day	9% 2 12% 28% 35% 14%	330
	21st to end	Day	10% 4 13% 33% 32% 8%	330
October	1st to 10th	Day	6% 2 23% 39% 23% 6%	330
	11th to 20th	Day	9% 7% 27% 34% 17% 6%	330
	21st to end	Day	22% 9% 29% 23% 12% 5%	363
November	1st to 10th	Day	14% 8% 29% 31% 15% 2	330
	11th to 20th	Day	17% 10% 33% 29% 10% 1	330
	21st to end	Day	19% 19% 35% 20% 5% 2	330
December	1st to 10th	Day	21% 10% 38% 20% 9% 2	330
	11th to 20th	Day	25% 13% 35% 19% 8% 1	330
	21st to end	Day	23% 16% 34% 21% 4 2	363
January	1st to 10th	Night	22% 11% 32% 29% 7%	1050
	11th to 20th	Night	22% 14% 30% 26% 7%	1031
	21st to end	Night	25% 10% 32% 30% 3	1100
February	1st to 10th	Night	24% 12% 34% 26% 4	1000
	11th to 20th	Night	29% 13% 32% 22% 3	773
	21st to end	Night	27% 13% 37% 21% 2	495
March	1st to 10th	Night	24% 12% 33% 26% 4	600
	11th to 20th	Night	18% 15% 35% 27% 4 1	600
	21st to end	Night	18% 11% 37% 28% 6%	660
April	1st to 10th	Night	15% 12% 39% 27% 7%	600
	11th to 20th	Night	17% 13% 34% 27% 10%	593
	21st to end	Night	16% 10% 36% 28% 10%	600
May	1st to 10th	Night	14% 8% 37% 31% 9% 1	600
	11th to 20th	Night	15% 7% 30% 31% 16% 1	591
	21st to end	Night	8% 4 27% 38% 20% 2	650
June	1st to 10th	Night	7% 2 13% 42% 31% 4	600
	11th to 20th	Night	3 2 19% 48% 25% 4	600
	21st to end	Night	6% 3 10% 44% 32% 6%	600
July	1st to 10th	Night	7% 2 8% 37% 39% 7%	585
	11th to 20th	Night	4 1 8% 39% 41% 7%	582
	21st to end	Night	4 2 7% 39% 42% 6%	657
August	1st to 10th	Night	2 1 4 44% 41% 8%	597
	11th to 20th	Night	6% 1 4 40% 44% 6%	594
	21st to end	Night	9% 1 5% 34% 42% 8%	660
September	1st to 10th	Night	7% 2 7% 36% 42% 7%	600
	11th to 20th	Night	13% 2 7% 30% 41% 7%	600
	21st to end	Night	8% 2 12% 37% 36% 6%	600
October	1st to 10th	Night	6% 2 13% 39% 36% 5%	754
	11th to 20th	Night	13% 5% 20% 41% 20% 2	800
	21st to end	Night	15% 6% 25% 31% 20% 2	880
November	1st to 10th	Night	14% 5% 24% 35% 21% 2	820
	11th to 20th	Night	13% 9% 25% 39% 13%	840
	21st to end	Night	20% 10% 28% 28% 13%	907
December	1st to 10th	Night	24% 11% 27% 28% 10%	1050
	11th to 20th	Night	25% 10% 29% 31% 5%	1050
	21st to end	Night	23% 10% 28% 31% 7%	1155

Page generated at 2026-01-14 00:14:28. Version ac07

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