Batesburg-Leesville High School
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Batesburg-Leesville High School clear sky chart from 2005-11-06 to 2025-05-26.

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	12% 6% 2 6% 4 4 5% 4 6% 8% 43%	114553
	Night	13% 6% 2 6% 4 4 4 4 5% 7% 45%	114739
Transparency	Day	38% 6% 11% 19% 20% 7%	118282
	Night	37% 5% 10% 18% 21% 8%	119149
Seeing	Day	15% 10% 25% 24% 18% 7%	15975
	Night	15% 9% 25% 31% 18% 2	26102

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% 5% 2 4 3 3 3 3 4 6% 53%	4056
	11th to 20th	Day	12% 6% 2 4 3 3 3 2 3 5% 58%	4060
	21st to end	Day	16% 8% 3 6% 4 4 4 2 4 5% 45%	4466
February	1st to 10th	Day	14% 7% 2 6% 5% 4 4 4 6% 7% 41%	1860
	11th to 20th	Day	20% 7% 2 6% 3 3 3 2 4 6% 43%	1948
	21st to end	Day	17% 6% 3 6% 4 4 4 3 4 6% 44%	1681
March	1st to 10th	Day	21% 9% 3 7% 4 3 3 2 4 5% 40%	4935
	11th to 20th	Day	8% 4 2 5% 4 4 4 3 5% 7% 55%	4980
	21st to end	Day	15% 7% 3 7% 4 4 4 3 4 4 46%	5465
April	1st to 10th	Day	10% 5% 2 4 4 4 5% 4 6% 6% 50%	2200
	11th to 20th	Day	11% 6% 2 5% 4 4 4 3 6% 6% 49%	2314
	21st to end	Day	9% 5% 2 4 4 4 5% 5% 6% 8% 49%	2565
May	1st to 10th	Day	9% 7% 3 6% 5% 4 5% 4 7% 9% 41%	4212
	11th to 20th	Day	15% 8% 3 7% 4 5% 5% 4 6% 7% 36%	4211
	21st to end	Day	7% 4 2 4 4 5% 5% 5% 7% 10% 47%	4541
June	1st to 10th	Day	10% 5% 3 8% 6% 5% 5% 5% 9% 10% 35%	2470
	11th to 20th	Day	6% 6% 2 5% 5% 5% 6% 5% 9% 10% 42%	2470
	21st to end	Day	5% 5% 2 6% 5% 6% 7% 5% 10% 12% 37%	2470
July	1st to 10th	Day	12% 8% 3 8% 5% 6% 6% 6% 8% 11% 26%	4120
	11th to 20th	Day	5% 5% 2 6% 7% 7% 7% 7% 10% 14% 30%	4120
	21st to end	Day	8% 8% 3 9% 7% 7% 7% 7% 10% 13% 21%	4466
August	1st to 10th	Day	20% 6% 2 7% 5% 6% 7% 5% 7% 10% 24%	4104
	11th to 20th	Day	10% 5% 2 8% 6% 6% 7% 6% 9% 10% 30%	4044
	21st to end	Day	7% 4 2 6% 4 4 5% 5% 8% 10% 45%	4140
September	1st to 10th	Day	7% 6% 2 7% 6% 6% 5% 5% 7% 10% 40%	2090
	11th to 20th	Day	14% 7% 3 7% 5% 4 4 4 6% 8% 40%	2090
	21st to end	Day	15% 7% 3 6% 4 4 3 4 5% 6% 42%	2090
October	1st to 10th	Day	13% 6% 2 6% 3 3 2 3 5% 6% 51%	2014
	11th to 20th	Day	11% 4 2 4 3 3 3 2 3 5% 60%	1900
	21st to end	Day	11% 6% 2 5% 4 3 3 3 4 5% 57%	2090
November	1st to 10th	Day	13% 6% 2 5% 3 4 3 3 4 5% 53%	1957
	11th to 20th	Day	13% 6% 2 5% 3 2 3 3 4 6% 53%	1855
	21st to end	Day	13% 6% 2 6% 4 4 4 3 4 5% 49%	1800
December	1st to 10th	Day	11% 6% 2 5% 4 4 4 3 5% 5% 50%	2930
	11th to 20th	Day	14% 6% 2 6% 3 4 4 3 5% 6% 47%	3373
	21st to end	Day	21% 6% 2 5% 3 3 3 2 5% 6% 45%	4466
January	1st to 10th	Night	12% 4 2 5% 3 3 3 2 4 5% 57%	5889
	11th to 20th	Night	11% 6% 2 5% 4 3 4 3 5% 7% 49%	5900
	21st to end	Night	15% 9% 2 6% 4 3 3 3 4 5% 46%	6490
February	1st to 10th	Night	15% 6% 2 6% 4 4 4 3 5% 6% 46%	2538
	11th to 20th	Night	19% 7% 3 5% 4 4 3 3 4 5% 44%	2338
	21st to end	Night	14% 6% 2 5% 4 4 4 3 5% 6% 47%	1947
March	1st to 10th	Night	19% 8% 3 6% 4 4 4 3 4 6% 40%	4918
	11th to 20th	Night	11% 3 1 4 3 3 3 4 5% 7% 55%	4980
	21st to end	Night	14% 5% 2 5% 4 4 4 4 5% 7% 47%	5467
April	1st to 10th	Night	11% 5% 2 5% 4 5% 4 3 5% 7% 50%	2200
	11th to 20th	Night	10% 6% 2 5% 4 4 4 3 4 7% 53%	2034
	21st to end	Night	7% 4 2 5% 5% 3 4 4 6% 7% 53%	1850
May	1st to 10th	Night	9% 6% 3 6% 4 4 5% 4 7% 11% 41%	2903
	11th to 20th	Night	13% 7% 2 6% 5% 5% 4 5% 5% 9% 39%	2902
	21st to end	Night	6% 4 2 5% 4 4 4 5% 7% 10% 48%	3130
June	1st to 10th	Night	10% 7% 3 8% 5% 5% 5% 6% 8% 11% 32%	1710
	11th to 20th	Night	7% 6% 1 6% 5% 5% 6% 5% 7% 10% 42%	1710
	21st to end	Night	6% 5% 1 7% 6% 6% 6% 6% 10% 12% 35%	1710
July	1st to 10th	Night	11% 10% 3 8% 6% 5% 6% 5% 7% 10% 28%	2840
	11th to 20th	Night	7% 6% 2 8% 5% 5% 6% 6% 11% 13% 30%	2840
	21st to end	Night	10% 10% 3 10% 7% 6% 7% 6% 8% 10% 23%	3087
August	1st to 10th	Night	20% 8% 3 8% 5% 5% 6% 5% 8% 10% 22%	2825
	11th to 20th	Night	9% 7% 3 8% 5% 5% 6% 4 8% 11% 35%	2785
	21st to end	Night	6% 4 2 5% 4 4 5% 5% 7% 10% 49%	3479
September	1st to 10th	Night	9% 6% 3 5% 5% 5% 6% 5% 7% 10% 40%	2090
	11th to 20th	Night	12% 7% 3 7% 6% 5% 4 4 5% 7% 39%	2090
	21st to end	Night	15% 6% 3 6% 4 4 4 4 4 7% 44%	2090
October	1st to 10th	Night	11% 6% 2 6% 3 3 3 3 4 6% 52%	2166
	11th to 20th	Night	12% 5% 1 4 3 3 3 3 5% 6% 56%	2280
	21st to end	Night	10% 5% 2 5% 3 3 3 3 4 5% 57%	2508
November	1st to 10th	Night	12% 6% 2 5% 3 4 3 2 4 5% 54%	2341
	11th to 20th	Night	13% 6% 3 5% 3 3 3 3 4 6% 52%	2540
	21st to end	Night	13% 5% 2 5% 3 3 4 3 5% 7% 49%	2600
December	1st to 10th	Night	12% 6% 2 5% 3 3 3 3 4 6% 54%	4250
	11th to 20th	Night	16% 7% 3 6% 3 3 3 2 5% 6% 46%	4822
	21st to end	Night	19% 7% 2 6% 3 4 4 3 4 5% 42%	6490

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	32% 4 6% 21% 30% 7%	4057
	11th to 20th	Day	31% 3 4 16% 36% 10%	4060
	21st to end	Day	43% 2 4 17% 23% 11%	4466
February	1st to 10th	Day	41% 4 10% 20% 18% 6%	1860
	11th to 20th	Day	43% 4 5% 18% 24% 6%	1958
	21st to end	Day	42% 5% 8% 14% 22% 9%	1681
March	1st to 10th	Day	49% 3 5% 12% 21% 10%	4935
	11th to 20th	Day	29% 4 7% 15% 26% 19%	4980
	21st to end	Day	43% 3 6% 18% 22% 8%	5465
April	1st to 10th	Day	33% 6% 10% 20% 26% 6%	2200
	11th to 20th	Day	33% 5% 10% 20% 21% 10%	2314
	21st to end	Day	31% 7% 10% 27% 21% 4	2565
May	1st to 10th	Day	36% 9% 15% 24% 14% 2	4250
	11th to 20th	Day	45% 7% 13% 21% 14% 1	4215
	21st to end	Day	28% 9% 18% 21% 22% 2	4554
June	1st to 10th	Day	40% 11% 17% 21% 10% 2	2470
	11th to 20th	Day	33% 9% 16% 26% 14% 1	2470
	21st to end	Day	35% 12% 16% 22% 14% 2	2470
July	1st to 10th	Day	48% 8% 18% 17% 7% 2	4055
	11th to 20th	Day	40% 11% 26% 19% 4 1	4051
	21st to end	Day	49% 13% 20% 14% 4 1	4324
August	1st to 10th	Day	53% 8% 19% 15% 4	4091
	11th to 20th	Day	46% 7% 15% 18% 14% 1	4083
	21st to end	Day	33% 6% 14% 29% 17% 2	4140
September	1st to 10th	Day	36% 11% 15% 16% 17% 5%	2090
	11th to 20th	Day	42% 8% 10% 18% 18% 4	2090
	21st to end	Day	41% 6% 10% 19% 17% 7%	2090
October	1st to 10th	Day	33% 3 5% 17% 31% 10%	3352
	11th to 20th	Day	19% 2 5% 17% 27% 31%	3140
	21st to end	Day	27% 2 3 21% 32% 15%	3428
November	1st to 10th	Day	35% 3 7% 18% 25% 12%	1957
	11th to 20th	Day	32% 5% 7% 20% 25% 11%	1855
	21st to end	Day	37% 4 8% 19% 23% 9%	1800
December	1st to 10th	Day	36% 3 6% 18% 28% 10%	2930
	11th to 20th	Day	39% 2 10% 22% 20% 7%	3370
	21st to end	Day	41% 3 7% 23% 24% 2	4466
January	1st to 10th	Night	30% 3 6% 18% 35% 7%	5889
	11th to 20th	Night	34% 4 5% 17% 32% 8%	5900
	21st to end	Night	41% 3 4 14% 28% 10%	6490
February	1st to 10th	Night	40% 4 8% 20% 20% 8%	2538
	11th to 20th	Night	43% 4 6% 18% 21% 8%	2339
	21st to end	Night	37% 5% 9% 17% 20% 12%	1947
March	1st to 10th	Night	45% 4 7% 12% 24% 8%	4918
	11th to 20th	Night	28% 4 7% 13% 29% 20%	4980
	21st to end	Night	37% 4 7% 19% 21% 12%	5467
April	1st to 10th	Night	34% 4 11% 20% 23% 8%	2200
	11th to 20th	Night	32% 5% 8% 21% 23% 11%	2034
	21st to end	Night	29% 6% 11% 27% 22% 5%	1850
May	1st to 10th	Night	35% 9% 15% 24% 14% 3	2930
	11th to 20th	Night	39% 9% 16% 20% 16% 1	2903
	21st to end	Night	26% 11% 14% 25% 21% 3	3138
June	1st to 10th	Night	41% 11% 15% 20% 11% 2	1710
	11th to 20th	Night	35% 10% 17% 24% 13% 2	1710
	21st to end	Night	36% 13% 18% 20% 11% 2	1710
July	1st to 10th	Night	49% 8% 20% 14% 7% 2	2795
	11th to 20th	Night	40% 12% 28% 15% 4 1	2786
	21st to end	Night	53% 13% 19% 11% 4	2988
August	1st to 10th	Night	55% 9% 18% 14% 3	2814
	11th to 20th	Night	43% 7% 21% 20% 8% 1	2812
	21st to end	Night	29% 7% 15% 30% 17% 2	3479
September	1st to 10th	Night	37% 9% 16% 19% 14% 5%	2090
	11th to 20th	Night	42% 8% 12% 17% 17% 4	2090
	21st to end	Night	39% 7% 13% 18% 18% 5%	2090
October	1st to 10th	Night	35% 3 8% 16% 31% 7%	3608
	11th to 20th	Night	19% 3 5% 16% 25% 32%	3779
	21st to end	Night	25% 3 5% 19% 29% 19%	4120
November	1st to 10th	Night	33% 4 7% 16% 26% 13%	2341
	11th to 20th	Night	35% 3 6% 17% 25% 13%	2540
	21st to end	Night	34% 5% 9% 18% 25% 10%	2600
December	1st to 10th	Night	34% 3 6% 16% 31% 9%	4250
	11th to 20th	Night	41% 2 11% 18% 20% 8%	4824
	21st to end	Night	44% 3 5% 24% 20% 3	6490

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	17% 25% 41% 14% 3	300
	11th to 20th	Day	21% 23% 35% 18% 2	300
	21st to end	Day	22% 25% 38% 12% 2	330
February	1st to 10th	Day	16% 26% 38% 16% 4	300
	11th to 20th	Day	34% 20% 32% 12% 1	300
	21st to end	Day	24% 23% 35% 14% 4	280
March	1st to 10th	Day	20% 21% 31% 20% 8%	500
	11th to 20th	Day	18% 19% 40% 17% 5%	500
	21st to end	Day	19% 19% 37% 17% 8%	550
April	1st to 10th	Day	18% 17% 34% 22% 9%	500
	11th to 20th	Day	13% 14% 32% 24% 14% 3	492
	21st to end	Day	12% 10% 30% 27% 18% 3	500
May	1st to 10th	Day	11% 12% 34% 27% 13% 3	503
	11th to 20th	Day	18% 5% 20% 32% 16% 8%	527
	21st to end	Day	13% 7% 17% 27% 24% 12%	549
June	1st to 10th	Day	12% 4 15% 33% 26% 10%	490
	11th to 20th	Day	8% 4 19% 27% 28% 14%	490
	21st to end	Day	8% 2 15% 34% 27% 14%	490
July	1st to 10th	Day	10% 2 9% 24% 32% 24%	485
	11th to 20th	Day	7% 2 11% 24% 37% 19%	484
	21st to end	Day	7% 2 11% 32% 35% 13%	532
August	1st to 10th	Day	15% 4 12% 25% 30% 15%	486
	11th to 20th	Day	12% 5% 11% 24% 32% 17%	479
	21st to end	Day	13% 3 10% 26% 31% 17%	539
September	1st to 10th	Day	9% 3 12% 30% 32% 13%	490
	11th to 20th	Day	18% 3 13% 26% 28% 12%	490
	21st to end	Day	20% 2 17% 28% 26% 8%	490
October	1st to 10th	Day	15% 6% 22% 30% 19% 9%	490
	11th to 20th	Day	11% 7% 24% 32% 20% 6%	490
	21st to end	Day	13% 8% 27% 28% 19% 5%	539
November	1st to 10th	Day	20% 9% 26% 25% 15% 5%	495
	11th to 20th	Day	18% 13% 38% 23% 6% 3	355
	21st to end	Day	12% 16% 37% 25% 10% 1	300
December	1st to 10th	Day	24% 19% 34% 18% 4	300
	11th to 20th	Day	22% 14% 41% 16% 7% 1	300
	21st to end	Day	28% 19% 32% 15% 5% 2	330
January	1st to 10th	Night	19% 16% 34% 25% 6%	800
	11th to 20th	Night	17% 17% 34% 27% 6%	800
	21st to end	Night	19% 18% 38% 23% 3	880
February	1st to 10th	Night	18% 14% 35% 29% 5%	800
	11th to 20th	Night	22% 17% 35% 24% 2	783
	21st to end	Night	17% 18% 36% 25% 4	660
March	1st to 10th	Night	18% 12% 35% 30% 5%	800
	11th to 20th	Night	18% 12% 39% 24% 7%	800
	21st to end	Night	15% 15% 38% 24% 7%	880
April	1st to 10th	Night	14% 16% 33% 28% 9%	800
	11th to 20th	Night	14% 12% 31% 31% 11%	791
	21st to end	Night	9% 9% 31% 38% 13%	650
May	1st to 10th	Night	11% 7% 32% 37% 13%	600
	11th to 20th	Night	12% 4 30% 34% 18% 3	591
	21st to end	Night	9% 4 17% 39% 27% 4	634
June	1st to 10th	Night	11% 2 22% 38% 22% 5%	570
	11th to 20th	Night	9% 4 14% 35% 30% 9%	570
	21st to end	Night	8% 2 13% 40% 30% 7%	570
July	1st to 10th	Night	9% 1 9% 37% 36% 8%	555
	11th to 20th	Night	10% 2 6% 34% 38% 9%	552
	21st to end	Night	8% 2 11% 37% 38% 5%	624
August	1st to 10th	Night	13% 2 8% 32% 38% 8%	567
	11th to 20th	Night	15% 1 7% 33% 39% 4	564
	21st to end	Night	12% 2 11% 31% 40% 5%	765
September	1st to 10th	Night	12% 2 11% 34% 37% 5%	760
	11th to 20th	Night	15% 2 14% 28% 36% 4	760
	21st to end	Night	17% 3 15% 33% 27% 5%	760
October	1st to 10th	Night	14% 5% 18% 32% 26% 4	760
	11th to 20th	Night	15% 5% 24% 31% 22% 3	760
	21st to end	Night	11% 8% 24% 32% 22% 3	836
November	1st to 10th	Night	15% 8% 24% 32% 19% 3	780
	11th to 20th	Night	16% 10% 31% 30% 12% 1	800
	21st to end	Night	14% 10% 30% 29% 15% 1	800
December	1st to 10th	Night	18% 13% 28% 31% 9% 1	800
	11th to 20th	Night	20% 10% 27% 33% 10% 1	800
	21st to end	Night	25% 13% 27% 29% 7%	880

Page generated at 2025-05-23 09:21:04. Version ac07

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