Luling Skies Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Luling Skies Observatory clear sky chart from 2005-11-06 to 2024-10-20.

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	10% 6% 3 8% 6% 5% 6% 5% 7% 8% 37%	100374
	Night	11% 6% 2 5% 4 4 4 4 6% 9% 45%	98255
Transparency	Day	40% 9% 13% 18% 15% 5%	100193
	Night	35% 8% 15% 20% 16% 7%	98106
Seeing	Day	11% 5% 17% 24% 25% 17%	14598
	Night	11% 4 18% 31% 27% 8%	24179

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	15% 6% 3 7% 5% 5% 5% 4 6% 8% 37%	2847
	11th to 20th	Day	11% 6% 2 5% 4 3 3 3 4 5% 53%	2886
	21st to end	Day	22% 9% 3 7% 4 4 5% 3 4 6% 33%	3476
February	1st to 10th	Day	14% 10% 2 7% 4 5% 5% 4 5% 7% 37%	1900
	11th to 20th	Day	15% 8% 2 6% 3 3 4 3 5% 7% 42%	1848
	21st to end	Day	16% 8% 3 7% 5% 5% 5% 3 5% 7% 37%	1570
March	1st to 10th	Day	19% 10% 3 8% 6% 5% 5% 4 5% 7% 27%	3332
	11th to 20th	Day	13% 6% 3 7% 5% 5% 5% 5% 8% 10% 33%	3480
	21st to end	Day	11% 6% 2 6% 4 5% 5% 4 6% 7% 45%	3973
April	1st to 10th	Day	10% 6% 2 6% 5% 6% 5% 4 6% 8% 42%	2280
	11th to 20th	Day	12% 6% 3 7% 5% 5% 4 4 6% 9% 39%	2254
	21st to end	Day	7% 5% 3 6% 5% 5% 5% 4 6% 8% 47%	2280
May	1st to 10th	Day	8% 5% 2 8% 5% 6% 6% 5% 7% 10% 37%	3765
	11th to 20th	Day	10% 5% 3 7% 5% 5% 5% 4 7% 8% 41%	3764
	21st to end	Day	5% 4 2 6% 6% 6% 6% 5% 7% 10% 44%	4129
June	1st to 10th	Day	9% 6% 3 10% 7% 6% 7% 6% 8% 9% 28%	2280
	11th to 20th	Day	5% 5% 2 8% 8% 7% 9% 6% 9% 12% 28%	2404
	21st to end	Day	6% 7% 3 9% 9% 8% 8% 8% 8% 9% 22%	2470
July	1st to 10th	Day	7% 8% 3 9% 8% 9% 9% 6% 9% 12% 20%	4120
	11th to 20th	Day	6% 6% 3 11% 9% 9% 9% 8% 8% 10% 21%	4034
	21st to end	Day	7% 7% 3 12% 9% 8% 9% 7% 9% 10% 18%	4118
August	1st to 10th	Day	3 3 2 6% 4 5% 6% 5% 9% 11% 44%	3785
	11th to 20th	Day	5% 5% 2 7% 6% 6% 8% 7% 10% 12% 33%	3729
	21st to end	Day	7% 7% 3 12% 8% 6% 6% 5% 7% 7% 30%	4180
September	1st to 10th	Day	12% 7% 3 8% 7% 7% 7% 6% 7% 9% 28%	2280
	11th to 20th	Day	10% 6% 3 8% 6% 6% 6% 5% 7% 9% 34%	2233
	21st to end	Day	8% 4 3 7% 5% 4 6% 4 7% 7% 46%	2090
October	1st to 10th	Day	7% 3 2 6% 4 5% 4 4 6% 7% 52%	1990
	11th to 20th	Day	6% 4 2 6% 4 4 4 4 6% 8% 53%	1890
	21st to end	Day	10% 5% 2 5% 3 3 4 3 5% 7% 52%	1980
November	1st to 10th	Day	7% 5% 1 6% 3 4 4 5% 5% 7% 52%	1858
	11th to 20th	Day	9% 7% 2 5% 4 3 4 2 5% 7% 52%	1900
	21st to end	Day	12% 6% 2 6% 4 4 5% 4 6% 7% 42%	1723
December	1st to 10th	Day	13% 6% 3 6% 4 5% 5% 4 6% 6% 42%	1710
	11th to 20th	Day	14% 9% 2 8% 5% 4 3 4 5% 6% 39%	2344
	21st to end	Day	17% 8% 3 7% 5% 4 4 4 5% 6% 38%	3472
January	1st to 10th	Night	15% 9% 2 5% 4 4 4 4 5% 6% 43%	4088
	11th to 20th	Night	14% 6% 2 4 3 3 3 3 5% 6% 52%	4059
	21st to end	Night	23% 8% 2 4 4 3 3 2 4 7% 39%	4180
February	1st to 10th	Night	14% 7% 3 7% 4 4 4 3 6% 6% 42%	2280
	11th to 20th	Night	17% 7% 3 5% 3 3 3 3 5% 7% 44%	2218
	21st to end	Night	17% 7% 3 6% 4 4 4 3 6% 6% 41%	1884
March	1st to 10th	Night	22% 11% 3 8% 5% 4 4 4 5% 6% 31%	3549
	11th to 20th	Night	13% 8% 2 7% 5% 4 5% 4 7% 7% 38%	3480
	21st to end	Night	14% 7% 2 5% 4 4 4 3 5% 7% 45%	3658
April	1st to 10th	Night	13% 6% 2 5% 4 3 5% 4 6% 6% 46%	1900
	11th to 20th	Night	11% 6% 2 6% 4 4 5% 3 5% 7% 46%	1875
	21st to end	Night	5% 4 2 4 4 4 5% 4 6% 8% 54%	1900
May	1st to 10th	Night	13% 5% 3 6% 4 5% 4 4 6% 9% 41%	3130
	11th to 20th	Night	14% 6% 2 7% 4 5% 5% 4 6% 7% 42%	3129
	21st to end	Night	6% 3 1 4 3 4 4 5% 8% 12% 49%	3426
June	1st to 10th	Night	7% 5% 2 5% 4 5% 5% 5% 8% 12% 43%	1900
	11th to 20th	Night	3 5% 1 4 5% 4 5% 5% 9% 12% 47%	1766
	21st to end	Night	6% 5% 2 5% 4 4 4 5% 9% 12% 43%	1710
July	1st to 10th	Night	3 4 2 5% 6% 5% 7% 6% 9% 15% 38%	2850
	11th to 20th	Night	2 2 1 4 4 4 5% 5% 11% 15% 46%	2929
	21st to end	Night	3 4 2 6% 6% 6% 6% 6% 10% 15% 35%	3435
August	1st to 10th	Night	1 2 1 3 3 3 5% 4 8% 12% 58%	3144
	11th to 20th	Night	3 2 1 5% 4 4 6% 6% 10% 15% 44%	3100
	21st to end	Night	4 5% 2 7% 5% 6% 6% 5% 8% 10% 43%	3476
September	1st to 10th	Night	7% 6% 2 5% 5% 6% 6% 5% 8% 10% 39%	1900
	11th to 20th	Night	7% 4 2 6% 5% 5% 6% 5% 7% 10% 43%	1926
	21st to end	Night	8% 4 2 5% 3 4 4 4 6% 9% 53%	2090
October	1st to 10th	Night	6% 4 2 4 4 3 4 3 5% 6% 59%	2185
	11th to 20th	Night	6% 3 2 5% 3 2 4 3 5% 7% 61%	2275
	21st to end	Night	11% 4 2 5% 4 3 4 3 4 6% 56%	2376
November	1st to 10th	Night	9% 5% 2 5% 3 4 3 3 4 6% 56%	2220
	11th to 20th	Night	11% 5% 1 4 4 3 4 3 5% 6% 54%	2280
	21st to end	Night	10% 6% 2 6% 4 4 4 4 5% 6% 49%	2450
December	1st to 10th	Night	13% 7% 3 6% 5% 4 4 3 4 6% 46%	2470
	11th to 20th	Night	12% 9% 2 6% 4 4 4 4 5% 7% 43%	2837
	21st to end	Night	16% 10% 3 7% 4 4 4 3 4 5% 40%	4180

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	43% 5% 8% 16% 19% 10%	2848
	11th to 20th	Day	32% 5% 6% 18% 32% 7%	2886
	21st to end	Day	53% 5% 5% 12% 18% 6%	3476
February	1st to 10th	Day	45% 6% 9% 13% 17% 9%	1900
	11th to 20th	Day	40% 6% 9% 18% 18% 9%	1858
	21st to end	Day	46% 6% 10% 14% 17% 6%	1570
March	1st to 10th	Day	53% 7% 11% 15% 11% 3	3332
	11th to 20th	Day	43% 8% 12% 20% 13% 4	3480
	21st to end	Day	35% 8% 12% 16% 21% 9%	3973
April	1st to 10th	Day	36% 9% 14% 16% 17% 9%	2280
	11th to 20th	Day	40% 6% 10% 20% 16% 7%	2254
	21st to end	Day	31% 7% 11% 22% 22% 6%	2280
May	1st to 10th	Day	37% 12% 14% 22% 10% 4	3800
	11th to 20th	Day	37% 8% 11% 20% 21% 3	3768
	21st to end	Day	29% 10% 16% 34% 11% 1	4141
June	1st to 10th	Day	44% 11% 15% 20% 9% 1	2280
	11th to 20th	Day	41% 12% 15% 21% 11% 1	2404
	21st to end	Day	48% 13% 17% 15% 7%	2470
July	1st to 10th	Day	47% 14% 23% 14% 1	4056
	11th to 20th	Day	47% 17% 27% 7% 2	3965
	21st to end	Day	52% 15% 18% 12% 2	3987
August	1st to 10th	Day	27% 9% 17% 26% 21%	3773
	11th to 20th	Day	35% 13% 24% 22% 5% 1	3765
	21st to end	Day	49% 11% 13% 14% 11% 2	4179
September	1st to 10th	Day	46% 12% 17% 12% 10% 3	2280
	11th to 20th	Day	43% 9% 15% 15% 14% 4	2233
	21st to end	Day	35% 8% 12% 21% 15% 9%	2090
October	1st to 10th	Day	29% 6% 11% 19% 22% 13%	1990
	11th to 20th	Day	28% 6% 10% 19% 24% 14%	1890
	21st to end	Day	31% 5% 8% 17% 26% 14%	1980
November	1st to 10th	Day	29% 5% 9% 23% 26% 8%	1858
	11th to 20th	Day	32% 5% 6% 20% 24% 12%	1900
	21st to end	Day	39% 7% 8% 18% 18% 10%	1723
December	1st to 10th	Day	40% 7% 10% 21% 16% 7%	1710
	11th to 20th	Day	44% 5% 8% 14% 21% 8%	2342
	21st to end	Day	46% 7% 9% 13% 22% 3	3472
January	1st to 10th	Night	41% 5% 7% 15% 22% 10%	4088
	11th to 20th	Night	33% 5% 6% 18% 27% 10%	4059
	21st to end	Night	47% 4 6% 14% 20% 9%	4180
February	1st to 10th	Night	42% 4 8% 17% 19% 10%	2280
	11th to 20th	Night	41% 5% 7% 16% 19% 12%	2219
	21st to end	Night	42% 6% 11% 15% 15% 11%	1884
March	1st to 10th	Night	53% 7% 10% 13% 12% 5%	3549
	11th to 20th	Night	41% 9% 12% 18% 14% 6%	3480
	21st to end	Night	36% 5% 10% 22% 19% 7%	3658
April	1st to 10th	Night	36% 7% 12% 18% 16% 11%	1900
	11th to 20th	Night	37% 6% 11% 21% 17% 9%	1875
	21st to end	Night	27% 5% 11% 25% 25% 6%	1900
May	1st to 10th	Night	36% 10% 14% 23% 13% 4	3160
	11th to 20th	Night	39% 8% 11% 20% 21% 1	3130
	21st to end	Night	23% 9% 19% 34% 13% 1	3435
June	1st to 10th	Night	31% 10% 19% 28% 12%	1900
	11th to 20th	Night	26% 11% 21% 28% 13%	1766
	21st to end	Night	30% 13% 26% 22% 9%	1710
July	1st to 10th	Night	32% 14% 36% 17% 1	2805
	11th to 20th	Night	22% 17% 47% 11% 2	2875
	21st to end	Night	33% 20% 28% 18% 2	3325
August	1st to 10th	Night	16% 9% 25% 31% 19%	3132
	11th to 20th	Night	23% 13% 34% 27% 2	3130
	21st to end	Night	35% 12% 20% 20% 11% 3	3476
September	1st to 10th	Night	35% 12% 22% 16% 12% 3	1900
	11th to 20th	Night	33% 12% 16% 18% 15% 6%	1926
	21st to end	Night	28% 7% 14% 27% 15% 9%	2090
October	1st to 10th	Night	26% 5% 11% 22% 21% 15%	2185
	11th to 20th	Night	23% 5% 9% 21% 26% 15%	2275
	21st to end	Night	30% 4 7% 16% 29% 15%	2376
November	1st to 10th	Night	29% 6% 7% 22% 25% 11%	2220
	11th to 20th	Night	31% 4 8% 18% 27% 12%	2280
	21st to end	Night	36% 5% 7% 20% 22% 10%	2450
December	1st to 10th	Night	39% 5% 9% 22% 19% 7%	2470
	11th to 20th	Night	40% 6% 8% 15% 17% 14%	2838
	21st to end	Night	47% 5% 9% 16% 17% 7%	4180

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	16% 14% 33% 29% 7% 2	270
	11th to 20th	Day	13% 15% 29% 32% 10% 1	270
	21st to end	Day	21% 13% 38% 23% 5% 1	297
February	1st to 10th	Day	19% 11% 37% 24% 7% 1	270
	11th to 20th	Day	24% 9% 32% 23% 11% 1	270
	21st to end	Day	10% 16% 44% 22% 7%	225
March	1st to 10th	Day	14% 13% 37% 27% 8% 1	270
	11th to 20th	Day	17% 13% 34% 27% 8% 1	270
	21st to end	Day	14% 8% 33% 31% 11% 2	392
April	1st to 10th	Day	11% 10% 32% 33% 13% 2	460
	11th to 20th	Day	16% 12% 27% 25% 17% 2	452
	21st to end	Day	7% 7% 24% 35% 24% 4	460
May	1st to 10th	Day	8% 6% 22% 32% 26% 6%	463
	11th to 20th	Day	8% 4 18% 31% 29% 10%	487
	21st to end	Day	6% 1 8% 31% 35% 19%	529
June	1st to 10th	Day	9% 2 9% 23% 32% 24%	490
	11th to 20th	Day	8% 2 9% 24% 36% 22%	614
	21st to end	Day	8% 1 8% 24% 32% 27%	680
July	1st to 10th	Day	11% 3 4 17% 33% 33%	671
	11th to 20th	Day	6% 2 4 10% 36% 40%	621
	21st to end	Day	9% 4 13% 32% 42%	532
August	1st to 10th	Day	4 1 3 14% 35% 43%	486
	11th to 20th	Day	9% 1 2 10% 29% 49%	479
	21st to end	Day	9% 3 8% 14% 33% 34%	539
September	1st to 10th	Day	12% 2 6% 16% 36% 29%	490
	11th to 20th	Day	11% 2 8% 20% 36% 22%	490
	21st to end	Day	9% 3 7% 25% 38% 19%	490
October	1st to 10th	Day	6% 2 14% 39% 29% 10%	390
	11th to 20th	Day	6% 4 15% 37% 26% 12%	297
	21st to end	Day	17% 7% 18% 29% 22% 7%	297
November	1st to 10th	Day	12% 3 16% 33% 30% 7%	270
	11th to 20th	Day	16% 7% 26% 28% 19% 4	270
	21st to end	Day	16% 9% 29% 30% 13% 4	270
December	1st to 10th	Day	16% 7% 30% 26% 15% 7%	270
	11th to 20th	Day	16% 11% 34% 31% 7%	270
	21st to end	Day	23% 7% 30% 23% 14% 2	297
January	1st to 10th	Night	18% 8% 30% 36% 8% 1	943
	11th to 20th	Night	17% 7% 27% 40% 10%	915
	21st to end	Night	20% 8% 34% 33% 7%	836
February	1st to 10th	Night	17% 7% 30% 37% 7% 1	760
	11th to 20th	Night	19% 8% 29% 32% 10%	743
	21st to end	Night	18% 10% 35% 32% 5%	628
March	1st to 10th	Night	14% 10% 31% 34% 11%	654
	11th to 20th	Night	15% 4 28% 38% 16% 1	570
	21st to end	Night	11% 8% 26% 37% 17%	627
April	1st to 10th	Night	14% 8% 25% 38% 14% 1	570
	11th to 20th	Night	13% 8% 28% 34% 17% 1	563
	21st to end	Night	6% 5% 23% 42% 22% 1	570
May	1st to 10th	Night	8% 3 17% 44% 27% 1	570
	11th to 20th	Night	8% 2 13% 44% 30% 3	561
	21st to end	Night	6% 1 9% 34% 40% 10%	617
June	1st to 10th	Night	8% 2 4 33% 45% 9%	570
	11th to 20th	Night	4 1 5% 23% 53% 14%	570
	21st to end	Night	8% 1 7% 21% 43% 21%	570
July	1st to 10th	Night	6% 1 3 12% 49% 28%	555
	11th to 20th	Night	4 1 1 5% 52% 36%	552
	21st to end	Night	5% 2 13% 50% 29%	624
August	1st to 10th	Night	2 1 12% 49% 36%	567
	11th to 20th	Night	5% 1 2 9% 45% 38%	564
	21st to end	Night	7% 1 5% 15% 45% 27%	627
September	1st to 10th	Night	9% 1 3 17% 47% 23%	570
	11th to 20th	Night	9% 1 5% 23% 49% 14%	596
	21st to end	Night	9% 2 7% 28% 44% 10%	760
October	1st to 10th	Night	7% 1 11% 38% 37% 6%	760
	11th to 20th	Night	7% 4 16% 35% 33% 6%	759
	21st to end	Night	13% 4 19% 35% 27% 3	792
November	1st to 10th	Night	10% 4 13% 41% 29% 3	740
	11th to 20th	Night	14% 4 20% 39% 21% 2	760
	21st to end	Night	12% 5% 25% 38% 18% 1	760
December	1st to 10th	Night	15% 7% 24% 33% 20% 1	760
	11th to 20th	Night	16% 5% 25% 39% 14% 1	760
	21st to end	Night	21% 8% 26% 33% 11% 1	836

Page generated at 2024-10-17 12:09:42. Version ac07

Copyright © 2024 Attilla Danko.