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 2024-11-25.

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% 7% 2 6% 4 4 4 4 6% 7% 42%	101269
	Night	13% 6% 2 5% 4 3 4 3 5% 7% 47%	98282
Transparency	Day	39% 6% 11% 20% 18% 6%	104931
	Night	35% 5% 11% 20% 20% 9%	102747
Seeing	Day	14% 8% 22% 26% 23% 7%	15074
	Night	16% 7% 24% 33% 18% 2	24904

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	18% 8% 3 6% 4 3 3 4 4 6% 40%	2847
	11th to 20th	Day	21% 6% 2 3 3 2 3 2 3 5% 51%	2850
	21st to end	Day	24% 8% 3 5% 3 2 2 2 3 6% 41%	3135
February	1st to 10th	Day	21% 9% 3 7% 5% 3 4 3 3 4 38%	1710
	11th to 20th	Day	23% 9% 2 5% 5% 4 3 2 3 5% 40%	1875
	21st to end	Day	22% 7% 3 6% 3 3 4 3 4 5% 40%	1727
March	1st to 10th	Day	20% 12% 4 9% 5% 4 4 3 4 5% 30%	3436
	11th to 20th	Day	20% 7% 3 6% 4 5% 4 4 6% 7% 33%	3480
	21st to end	Day	17% 9% 3 7% 5% 4 4 3 4 6% 38%	3814
April	1st to 10th	Day	14% 8% 3 7% 5% 3 4 4 5% 6% 40%	2112
	11th to 20th	Day	15% 8% 2 6% 4 4 5% 4 5% 7% 39%	2254
	21st to end	Day	11% 6% 1 6% 6% 4 4 4 5% 6% 45%	2280
May	1st to 10th	Day	18% 9% 3 7% 5% 5% 5% 4 7% 7% 29%	3825
	11th to 20th	Day	15% 6% 3 6% 4 5% 4 4 5% 7% 43%	4082
	21st to end	Day	11% 7% 3 8% 6% 5% 6% 5% 7% 10% 32%	4477
June	1st to 10th	Day	7% 4 2 7% 6% 5% 6% 5% 8% 11% 39%	2470
	11th to 20th	Day	5% 4 2 5% 5% 5% 7% 6% 8% 11% 42%	2470
	21st to end	Day	6% 6% 2 7% 5% 6% 6% 5% 8% 11% 37%	2470
July	1st to 10th	Day	10% 5% 2 5% 6% 6% 6% 5% 8% 11% 37%	4120
	11th to 20th	Day	6% 6% 2 7% 5% 6% 6% 6% 8% 10% 38%	4120
	21st to end	Day	16% 9% 3 8% 5% 4 4 4 6% 8% 33%	4465
August	1st to 10th	Day	2 2 1 3 3 3 4 3 5% 9% 66%	4104
	11th to 20th	Day	3 3 1 4 3 3 4 3 8% 11% 57%	3855
	21st to end	Day	7% 4 2 6% 5% 6% 6% 6% 9% 11% 39%	4180
September	1st to 10th	Day	6% 5% 3 7% 5% 5% 5% 5% 7% 8% 44%	2176
	11th to 20th	Day	13% 5% 2 6% 5% 5% 5% 4 6% 8% 42%	2090
	21st to end	Day	7% 5% 1 5% 4 4 4 4 8% 8% 51%	2090
October	1st to 10th	Day	7% 4 2 4 3 3 4 2 5% 6% 61%	1924
	11th to 20th	Day	11% 6% 1 4 3 3 4 3 4 6% 55%	1900
	21st to end	Day	14% 6% 2 5% 2 3 3 3 4 5% 53%	2090
November	1st to 10th	Day	11% 7% 2 5% 4 4 5% 3 6% 7% 46%	1958
	11th to 20th	Day	12% 6% 2 5% 4 3 3 3 4 6% 51%	2000
	21st to end	Day	18% 7% 2 6% 4 3 3 3 4 5% 45%	1877
December	1st to 10th	Day	17% 7% 3 6% 3 3 4 3 4 5% 44%	1710
	11th to 20th	Day	18% 8% 3 5% 5% 4 4 3 4 5% 42%	2161
	21st to end	Day	16% 10% 4 8% 3 3 3 3 4 5% 41%	3135
January	1st to 10th	Night	16% 7% 2 5% 3 3 3 3 4 5% 49%	4108
	11th to 20th	Night	19% 6% 2 5% 2 2 2 2 3 4 52%	4120
	21st to end	Night	23% 12% 2 5% 3 2 3 2 3 6% 40%	4532
February	1st to 10th	Night	18% 8% 3 5% 4 3 3 3 4 6% 43%	2470
	11th to 20th	Night	21% 8% 3 6% 4 3 4 2 2 4 44%	2209
	21st to end	Night	21% 6% 2 5% 3 3 3 3 4 6% 43%	1727
March	1st to 10th	Night	24% 10% 2 7% 4 4 3 3 4 6% 34%	3419
	11th to 20th	Night	19% 8% 2 7% 5% 4 4 3 5% 6% 35%	3480
	21st to end	Night	14% 7% 2 7% 5% 4 4 3 5% 5% 43%	3817
April	1st to 10th	Night	12% 6% 2 6% 4 5% 4 4 5% 7% 44%	2066
	11th to 20th	Night	14% 6% 2 6% 4 4 4 3 5% 7% 44%	1875
	21st to end	Night	12% 7% 2 6% 4 3 4 3 4 6% 49%	1900
May	1st to 10th	Night	15% 9% 3 8% 5% 4 4 3 6% 8% 34%	3054
	11th to 20th	Night	14% 7% 3 6% 4 4 4 3 4 6% 44%	2823
	21st to end	Night	10% 5% 2 7% 5% 5% 4 6% 8% 10% 39%	3090
June	1st to 10th	Night	6% 4 1 5% 3 3 4 4 7% 11% 50%	1710
	11th to 20th	Night	2 3 1 4 3 3 3 4 7% 12% 57%	1710
	21st to end	Night	6% 4 2 5% 5% 4 5% 5% 7% 11% 47%	1710
July	1st to 10th	Night	8% 4 2 6% 5% 4 5% 5% 8% 12% 42%	2850
	11th to 20th	Night	3 4 2 5% 4 5% 5% 5% 8% 11% 48%	2850
	21st to end	Night	13% 8% 3 7% 3 4 4 4 6% 10% 38%	3098
August	1st to 10th	Night	1 1 1 2 1 2 2 3 4 9% 73%	2836
	11th to 20th	Night	3 2 1 3 2 3 4 4 7% 13% 58%	2975
	21st to end	Night	5% 4 2 7% 5% 5% 5% 5% 7% 10% 44%	3476
September	1st to 10th	Night	6% 5% 3 7% 4 4 4 4 6% 6% 52%	2000
	11th to 20th	Night	11% 7% 2 7% 4 3 5% 3 5% 8% 47%	2090
	21st to end	Night	7% 4 1 4 3 3 4 4 7% 7% 56%	2090
October	1st to 10th	Night	4 3 1 3 3 4 4 3 4 7% 62%	2236
	11th to 20th	Night	10% 5% 2 4 3 3 3 3 5% 5% 59%	2280
	21st to end	Night	13% 4 2 3 2 3 3 2 4 5% 59%	2508
November	1st to 10th	Night	13% 5% 2 4 4 3 3 3 4 6% 52%	2340
	11th to 20th	Night	10% 6% 2 5% 3 3 4 3 3 6% 54%	2400
	21st to end	Night	17% 7% 2 6% 3 3 3 3 5% 6% 47%	2395
December	1st to 10th	Night	18% 7% 2 5% 3 3 4 3 5% 5% 44%	2470
	11th to 20th	Night	17% 8% 3 6% 4 3 4 2 4 5% 45%	3036
	21st to end	Night	17% 7% 2 5% 4 3 3 3 4 5% 47%	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	44% 5% 4 18% 24% 5%	2848
	11th to 20th	Day	38% 3 4 21% 29% 5%	2850
	21st to end	Day	47% 2 3 18% 19% 10%	3135
February	1st to 10th	Day	51% 4 5% 13% 18% 9%	1710
	11th to 20th	Day	50% 3 5% 15% 18% 9%	1885
	21st to end	Day	48% 4 6% 13% 18% 11%	1727
March	1st to 10th	Day	57% 4 6% 12% 16% 4	3436
	11th to 20th	Day	49% 5% 7% 19% 15% 5%	3480
	21st to end	Day	47% 4 8% 16% 21% 3	3814
April	1st to 10th	Day	44% 6% 7% 18% 17% 8%	2112
	11th to 20th	Day	43% 5% 11% 15% 17% 9%	2254
	21st to end	Day	39% 5% 9% 19% 24% 5%	2280
May	1st to 10th	Day	52% 6% 12% 17% 10% 3	3860
	11th to 20th	Day	40% 5% 10% 18% 25% 1	4086
	21st to end	Day	43% 9% 14% 22% 11% 1	4489
June	1st to 10th	Day	36% 9% 15% 23% 15% 1	2470
	11th to 20th	Day	33% 8% 14% 26% 16% 2	2470
	21st to end	Day	39% 9% 14% 23% 13% 2	2470
July	1st to 10th	Day	39% 8% 25% 24% 5%	4056
	11th to 20th	Day	38% 7% 16% 27% 11%	4051
	21st to end	Day	48% 7% 15% 22% 7%	4325
August	1st to 10th	Day	15% 6% 14% 35% 28% 1	4090
	11th to 20th	Day	20% 6% 25% 39% 10% 1	3894
	21st to end	Day	36% 9% 19% 20% 15% 1	4179
September	1st to 10th	Day	36% 8% 13% 19% 15% 8%	2176
	11th to 20th	Day	40% 7% 13% 16% 18% 7%	2090
	21st to end	Day	29% 6% 11% 22% 20% 13%	2090
October	1st to 10th	Day	16% 3 6% 13% 23% 38%	3197
	11th to 20th	Day	20% 3 4 22% 30% 22%	3140
	21st to end	Day	28% 3 4 14% 38% 13%	3428
November	1st to 10th	Day	37% 5% 8% 18% 22% 9%	1958
	11th to 20th	Day	35% 4 6% 18% 24% 13%	2000
	21st to end	Day	42% 5% 6% 18% 21% 9%	1877
December	1st to 10th	Day	43% 3 11% 16% 19% 8%	1710
	11th to 20th	Day	45% 4 5% 15% 22% 8%	2159
	21st to end	Day	47% 3 5% 13% 25% 8%	3135
January	1st to 10th	Night	38% 4 5% 18% 27% 8%	4108
	11th to 20th	Night	39% 3 5% 17% 27% 10%	4120
	21st to end	Night	49% 2 5% 16% 18% 10%	4532
February	1st to 10th	Night	43% 4 6% 15% 18% 13%	2470
	11th to 20th	Night	47% 4 5% 15% 20% 11%	2209
	21st to end	Night	43% 4 8% 13% 17% 15%	1727
March	1st to 10th	Night	53% 4 6% 14% 16% 7%	3419
	11th to 20th	Night	50% 5% 8% 14% 17% 5%	3480
	21st to end	Night	43% 5% 9% 14% 23% 6%	3817
April	1st to 10th	Night	39% 5% 9% 19% 16% 12%	2066
	11th to 20th	Night	39% 6% 9% 19% 16% 12%	1875
	21st to end	Night	36% 5% 9% 18% 25% 7%	1900
May	1st to 10th	Night	46% 7% 10% 19% 14% 4	3084
	11th to 20th	Night	42% 4 10% 18% 23% 3	2824
	21st to end	Night	37% 7% 17% 26% 11% 2	3099
June	1st to 10th	Night	26% 8% 18% 29% 17% 1	1710
	11th to 20th	Night	20% 8% 18% 32% 18% 4	1710
	21st to end	Night	29% 8% 15% 29% 17% 1	1710
July	1st to 10th	Night	33% 8% 31% 22% 5%	2805
	11th to 20th	Night	28% 8% 23% 29% 10%	2796
	21st to end	Night	42% 7% 21% 22% 8%	2999
August	1st to 10th	Night	10% 5% 17% 34% 32% 2	2826
	11th to 20th	Night	18% 6% 24% 42% 9% 1	3002
	21st to end	Night	33% 10% 18% 22% 15% 2	3476
September	1st to 10th	Night	31% 7% 16% 20% 16% 9%	2000
	11th to 20th	Night	36% 6% 13% 20% 17% 8%	2090
	21st to end	Night	25% 6% 11% 22% 23% 13%	2090
October	1st to 10th	Night	14% 4 5% 15% 20% 42%	3730
	11th to 20th	Night	16% 2 4 20% 32% 25%	3779
	21st to end	Night	24% 3 4 15% 39% 15%	4120
November	1st to 10th	Night	34% 4 9% 18% 23% 11%	2340
	11th to 20th	Night	33% 3 7% 18% 24% 14%	2400
	21st to end	Night	39% 4 7% 17% 23% 11%	2395
December	1st to 10th	Night	42% 4 9% 18% 19% 9%	2470
	11th to 20th	Night	44% 3 5% 13% 22% 13%	3037
	21st to end	Night	40% 4 6% 14% 29% 7%	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	24% 16% 39% 16% 6%	270
	11th to 20th	Day	30% 11% 34% 19% 4 1	270
	21st to end	Day	27% 19% 35% 16% 3	297
February	1st to 10th	Day	29% 19% 34% 15% 3	270
	11th to 20th	Day	36% 15% 33% 15% 1	270
	21st to end	Day	27% 24% 39% 9% 1	225
March	1st to 10th	Day	26% 19% 37% 13% 5%	270
	11th to 20th	Day	23% 21% 39% 15% 2 1	270
	21st to end	Day	23% 13% 44% 18% 2 1	297
April	1st to 10th	Day	22% 18% 39% 19% 3	292
	11th to 20th	Day	25% 14% 27% 22% 11%	452
	21st to end	Day	16% 12% 36% 26% 8% 2	460
May	1st to 10th	Day	17% 11% 35% 28% 8%	497
	11th to 20th	Day	15% 7% 27% 32% 18% 2	675
	21st to end	Day	11% 7% 27% 32% 17% 5%	734
June	1st to 10th	Day	7% 3 16% 34% 31% 9%	680
	11th to 20th	Day	5% 1 18% 39% 30% 7%	680
	21st to end	Day	8% 3 13% 29% 34% 13%	680
July	1st to 10th	Day	8% 2 9% 27% 39% 15%	671
	11th to 20th	Day	5% 1 5% 29% 45% 14%	668
	21st to end	Day	6% 1 6% 28% 43% 15%	739
August	1st to 10th	Day	4 1 4 26% 47% 18%	676
	11th to 20th	Day	6% 1 2 25% 45% 20%	557
	21st to end	Day	11% 3 6% 20% 39% 22%	539
September	1st to 10th	Day	5% 2 8% 29% 40% 16%	386
	11th to 20th	Day	10% 3 12% 30% 34% 11%	300
	21st to end	Day	10% 3 12% 34% 32% 9%	300
October	1st to 10th	Day	7% 2 24% 39% 22% 6%	300
	11th to 20th	Day	10% 7% 28% 34% 16% 5%	300
	21st to end	Day	23% 9% 28% 22% 13% 5%	330
November	1st to 10th	Day	15% 9% 29% 32% 13% 2	300
	11th to 20th	Day	19% 10% 32% 27% 10% 1	300
	21st to end	Day	20% 17% 35% 20% 6% 2	282
December	1st to 10th	Day	19% 12% 36% 21% 10% 3	270
	11th to 20th	Day	26% 15% 34% 19% 6%	270
	21st to end	Day	24% 17% 35% 19% 4 2	297
January	1st to 10th	Night	21% 11% 32% 29% 7%	950
	11th to 20th	Night	24% 14% 29% 26% 7%	950
	21st to end	Night	24% 10% 32% 30% 3	1045
February	1st to 10th	Night	23% 12% 34% 27% 4	950
	11th to 20th	Night	28% 13% 33% 23% 4	735
	21st to end	Night	27% 14% 37% 21% 1	471
March	1st to 10th	Night	24% 12% 33% 27% 5%	570
	11th to 20th	Night	18% 14% 35% 28% 4 1	570
	21st to end	Night	18% 11% 37% 28% 6%	627
April	1st to 10th	Night	14% 12% 40% 27% 7%	570
	11th to 20th	Night	17% 13% 34% 27% 10%	563
	21st to end	Night	16% 10% 36% 28% 11%	570
May	1st to 10th	Night	14% 8% 39% 31% 8% 1	570
	11th to 20th	Night	15% 6% 30% 32% 16% 1	561
	21st to end	Night	8% 4 27% 38% 21% 2	617
June	1st to 10th	Night	7% 2 11% 43% 32% 4	570
	11th to 20th	Night	3 2 18% 48% 25% 4	570
	21st to end	Night	7% 3 10% 44% 31% 6%	570
July	1st to 10th	Night	6% 2 8% 38% 39% 7%	555
	11th to 20th	Night	4 1 8% 40% 40% 7%	552
	21st to end	Night	4 1 6% 39% 43% 6%	624
August	1st to 10th	Night	2 1 5% 43% 42% 7%	567
	11th to 20th	Night	6% 1 4 40% 44% 5%	564
	21st to end	Night	9% 1 5% 34% 43% 8%	627
September	1st to 10th	Night	7% 2 7% 35% 43% 7%	570
	11th to 20th	Night	14% 2 7% 30% 40% 6%	570
	21st to end	Night	8% 2 11% 35% 36% 7%	570
October	1st to 10th	Night	6% 2 13% 39% 35% 5%	716
	11th to 20th	Night	13% 6% 20% 41% 19% 3	760
	21st to end	Night	15% 6% 26% 31% 20% 2	836
November	1st to 10th	Night	14% 4 24% 35% 20% 2	780
	11th to 20th	Night	14% 9% 25% 38% 13%	800
	21st to end	Night	20% 10% 27% 29% 14% 1	839
December	1st to 10th	Night	22% 11% 27% 28% 11% 1	950
	11th to 20th	Night	25% 10% 29% 30% 5%	950
	21st to end	Night	24% 9% 29% 30% 7%	1045

Page generated at 2024-11-22 07:02:30. Version ac07

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