Liberty University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Liberty University clear sky chart from 2005-11-06 to 2024-11-04.

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	14% 6% 2 6% 4 4 4 4 6% 8% 42%	100772
	Night	14% 6% 2 6% 4 4 4 4 5% 7% 43%	98147
Transparency	Day	38% 6% 12% 23% 17% 4	104421
	Night	38% 6% 11% 22% 18% 5%	102637
Seeing	Day	19% 11% 24% 25% 15% 6%	15107
	Night	17% 9% 26% 32% 16% 2	25131

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% 5% 2 4 3 3 4 3 4 6% 50%	2836
	11th to 20th	Day	15% 6% 2 7% 4 5% 3 4 5% 6% 45%	2840
	21st to end	Day	21% 8% 2 6% 3 3 4 3 4 5% 41%	3124
February	1st to 10th	Day	13% 7% 2 5% 4 5% 5% 4 7% 7% 42%	1710
	11th to 20th	Day	20% 5% 2 5% 3 5% 4 3 5% 7% 43%	1663
	21st to end	Day	20% 7% 3 6% 4 3 4 3 5% 6% 38%	1669
March	1st to 10th	Day	21% 8% 2 6% 4 3 4 3 5% 7% 37%	3435
	11th to 20th	Day	10% 5% 2 5% 3 4 4 3 6% 7% 52%	3480
	21st to end	Day	20% 6% 3 6% 5% 4 4 3 5% 5% 38%	3815
April	1st to 10th	Day	11% 5% 2 5% 4 4 4 3 5% 7% 50%	2204
	11th to 20th	Day	13% 6% 2 5% 4 4 4 3 5% 8% 47%	2254
	21st to end	Day	16% 6% 2 6% 5% 4 4 3 5% 7% 42%	2337
May	1st to 10th	Day	15% 6% 3 7% 5% 5% 6% 5% 7% 9% 32%	4082
	11th to 20th	Day	20% 7% 2 6% 4 4 4 4 5% 8% 34%	4081
	21st to end	Day	9% 4 2 5% 4 5% 5% 4 8% 10% 45%	4476
June	1st to 10th	Day	9% 4 2 6% 5% 5% 5% 4 6% 10% 44%	2591
	11th to 20th	Day	10% 5% 2 6% 4 5% 5% 5% 7% 11% 40%	2660
	21st to end	Day	7% 5% 2 6% 5% 5% 5% 5% 8% 11% 41%	2501
July	1st to 10th	Day	6% 5% 2 6% 5% 5% 6% 5% 9% 12% 40%	4120
	11th to 20th	Day	9% 6% 2 6% 5% 5% 6% 5% 8% 12% 36%	4120
	21st to end	Day	12% 7% 3 8% 6% 6% 7% 5% 8% 9% 29%	4466
August	1st to 10th	Day	14% 7% 2 7% 5% 5% 5% 5% 7% 11% 31%	4104
	11th to 20th	Day	9% 5% 2 6% 5% 5% 6% 5% 8% 10% 40%	3994
	21st to end	Day	9% 4 2 5% 3 4 4 4 6% 11% 48%	4180
September	1st to 10th	Day	12% 5% 2 6% 3 4 4 4 5% 7% 48%	2280
	11th to 20th	Day	14% 6% 3 5% 4 3 4 4 5% 7% 44%	2137
	21st to end	Day	22% 7% 3 6% 5% 4 3 3 5% 6% 36%	2059
October	1st to 10th	Day	15% 6% 2 4 4 3 2 2 4 6% 51%	1900
	11th to 20th	Day	16% 4 1 4 3 3 3 3 4 6% 53%	1900
	21st to end	Day	12% 5% 2 5% 3 3 4 3 3 6% 53%	2090
November	1st to 10th	Day	12% 5% 2 4 3 3 3 3 4 6% 55%	1887
	11th to 20th	Day	15% 5% 2 5% 4 3 3 3 5% 6% 50%	1788
	21st to end	Day	14% 5% 1 5% 3 2 3 3 5% 8% 50%	1520
December	1st to 10th	Day	17% 7% 2 5% 3 5% 5% 4 7% 8% 38%	1520
	11th to 20th	Day	16% 5% 2 4 3 2 3 2 4 6% 53%	1910
	21st to end	Day	19% 6% 2 5% 4 4 5% 3 5% 8% 39%	3039
January	1st to 10th	Night	14% 7% 2 5% 3 4 3 3 5% 5% 49%	4109
	11th to 20th	Night	16% 7% 2 5% 3 3 3 3 4 6% 48%	4120
	21st to end	Night	22% 7% 2 6% 3 4 3 2 4 5% 42%	4532
February	1st to 10th	Night	14% 7% 2 5% 4 3 3 4 7% 7% 44%	2470
	11th to 20th	Night	19% 7% 2 5% 3 3 3 3 5% 6% 43%	2403
	21st to end	Night	16% 7% 2 6% 4 4 4 3 4 6% 44%	1780
March	1st to 10th	Night	20% 7% 3 7% 4 4 4 4 5% 6% 35%	3418
	11th to 20th	Night	11% 4 1 4 4 3 4 3 5% 7% 52%	3480
	21st to end	Night	16% 7% 2 5% 3 3 3 3 5% 7% 47%	3817
April	1st to 10th	Night	14% 6% 2 5% 4 4 4 3 5% 6% 46%	1974
	11th to 20th	Night	12% 4 2 5% 4 3 4 3 6% 7% 49%	1875
	21st to end	Night	14% 5% 3 5% 5% 3 5% 4 6% 7% 44%	1857
May	1st to 10th	Night	16% 8% 2 8% 5% 5% 4 4 6% 7% 34%	2813
	11th to 20th	Night	23% 8% 3 6% 4 4 3 3 4 6% 36%	2812
	21st to end	Night	10% 4 2 5% 4 4 4 4 7% 10% 45%	3079
June	1st to 10th	Night	9% 4 2 6% 4 5% 5% 5% 7% 11% 42%	1578
	11th to 20th	Night	9% 5% 2 7% 5% 4 5% 4 6% 9% 43%	1520
	21st to end	Night	7% 5% 2 4 4 4 6% 5% 8% 11% 44%	1667
July	1st to 10th	Night	6% 5% 3 6% 5% 5% 6% 5% 8% 10% 41%	2840
	11th to 20th	Night	9% 6% 2 6% 5% 6% 5% 5% 8% 11% 38%	2840
	21st to end	Night	12% 9% 3 8% 6% 6% 6% 5% 7% 9% 30%	3087
August	1st to 10th	Night	17% 6% 3 8% 5% 5% 5% 5% 7% 9% 30%	2825
	11th to 20th	Night	8% 6% 2 7% 6% 5% 6% 5% 8% 9% 38%	2800
	21st to end	Night	10% 6% 2 5% 4 4 5% 4 6% 10% 44%	3476
September	1st to 10th	Night	11% 6% 2 5% 4 4 5% 5% 6% 7% 45%	1900
	11th to 20th	Night	15% 6% 2 6% 4 4 5% 3 6% 6% 44%	2039
	21st to end	Night	23% 8% 3 6% 4 4 3 3 4 6% 37%	2119
October	1st to 10th	Night	17% 5% 3 6% 3 3 3 2 4 6% 49%	2280
	11th to 20th	Night	13% 5% 2 5% 4 4 4 3 5% 6% 51%	2280
	21st to end	Night	13% 4 1 4 3 3 3 3 4 6% 56%	2508
November	1st to 10th	Night	13% 6% 3 5% 3 3 3 2 3 4 54%	2264
	11th to 20th	Night	13% 5% 2 5% 3 3 4 4 5% 6% 51%	2384
	21st to end	Night	13% 3 2 5% 4 4 4 4 5% 7% 50%	2660
December	1st to 10th	Night	18% 7% 3 6% 4 4 4 3 4 5% 42%	2660
	11th to 20th	Night	15% 7% 1 5% 4 3 3 3 4 7% 46%	3285
	21st to end	Night	17% 6% 2 6% 4 4 5% 4 6% 7% 40%	4596

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	35% 3 8% 29% 19% 6%	2837
	11th to 20th	Day	39% 4 8% 20% 24% 5%	2840
	21st to end	Day	47% 4 6% 23% 17% 3	3124
February	1st to 10th	Day	39% 5% 11% 25% 17% 4	1710
	11th to 20th	Day	41% 4 8% 22% 20% 5%	1672
	21st to end	Day	47% 5% 11% 16% 17% 5%	1669
March	1st to 10th	Day	47% 4 8% 20% 13% 7%	3435
	11th to 20th	Day	31% 6% 8% 25% 21% 10%	3480
	21st to end	Day	47% 6% 10% 18% 17% 3	3815
April	1st to 10th	Day	33% 5% 12% 23% 20% 8%	2204
	11th to 20th	Day	36% 5% 10% 23% 21% 6%	2254
	21st to end	Day	41% 6% 9% 23% 15% 5%	2337
May	1st to 10th	Day	46% 8% 13% 20% 11% 2	4120
	11th to 20th	Day	46% 7% 11% 23% 11% 1	4085
	21st to end	Day	31% 9% 16% 22% 20% 3	4489
June	1st to 10th	Day	34% 8% 16% 26% 15% 1	2591
	11th to 20th	Day	36% 9% 16% 22% 16% 2	2660
	21st to end	Day	34% 9% 16% 23% 16% 2	2501
July	1st to 10th	Day	34% 11% 22% 18% 10% 5%	4055
	11th to 20th	Day	38% 9% 19% 24% 10% 1	4051
	21st to end	Day	47% 10% 12% 19% 11%	4324
August	1st to 10th	Day	45% 8% 17% 24% 6% 1	4091
	11th to 20th	Day	36% 9% 17% 28% 10% 1	4033
	21st to end	Day	30% 7% 19% 27% 16% 1	4180
September	1st to 10th	Day	35% 7% 12% 20% 22% 4	2280
	11th to 20th	Day	39% 6% 8% 25% 19% 3	2137
	21st to end	Day	49% 5% 9% 17% 18% 2	2059
October	1st to 10th	Day	35% 4 7% 18% 29% 6%	3160
	11th to 20th	Day	25% 3 6% 24% 28% 15%	3140
	21st to end	Day	22% 4 12% 26% 25% 11%	3428
November	1st to 10th	Day	31% 4 9% 23% 28% 5%	1887
	11th to 20th	Day	35% 5% 9% 22% 21% 8%	1788
	21st to end	Day	34% 4 9% 24% 25% 4	1520
December	1st to 10th	Day	43% 6% 11% 20% 17% 4	1520
	11th to 20th	Day	34% 3 8% 26% 21% 8%	1906
	21st to end	Day	43% 4 11% 26% 14% 2	3039
January	1st to 10th	Night	37% 3 8% 24% 23% 5%	4109
	11th to 20th	Night	39% 4 7% 20% 25% 5%	4120
	21st to end	Night	46% 3 6% 23% 16% 6%	4532
February	1st to 10th	Night	37% 5% 11% 24% 19% 3	2470
	11th to 20th	Night	43% 4 8% 19% 19% 7%	2405
	21st to end	Night	41% 4 9% 24% 16% 6%	1780
March	1st to 10th	Night	49% 6% 8% 19% 16% 4	3418
	11th to 20th	Night	31% 5% 7% 20% 27% 10%	3480
	21st to end	Night	38% 5% 10% 23% 19% 5%	3817
April	1st to 10th	Night	38% 6% 10% 18% 22% 6%	1974
	11th to 20th	Night	33% 5% 11% 22% 22% 6%	1875
	21st to end	Night	38% 7% 11% 23% 18% 4	1857
May	1st to 10th	Night	47% 7% 13% 19% 12% 2	2840
	11th to 20th	Night	48% 7% 9% 22% 12% 1	2813
	21st to end	Night	32% 8% 17% 25% 14% 3	3087
June	1st to 10th	Night	33% 9% 15% 27% 16% 1	1578
	11th to 20th	Night	36% 7% 17% 20% 17% 2	1520
	21st to end	Night	31% 10% 16% 21% 17% 4	1667
July	1st to 10th	Night	35% 10% 21% 17% 13% 3	2795
	11th to 20th	Night	38% 9% 21% 22% 8% 1	2786
	21st to end	Night	49% 9% 13% 20% 9%	2988
August	1st to 10th	Night	47% 8% 16% 21% 7% 1	2814
	11th to 20th	Night	39% 8% 16% 25% 11% 1	2827
	21st to end	Night	35% 7% 14% 32% 10% 2	3476
September	1st to 10th	Night	37% 8% 13% 19% 18% 6%	1900
	11th to 20th	Night	39% 7% 10% 21% 20% 3	2039
	21st to end	Night	49% 5% 8% 18% 16% 3	2119
October	1st to 10th	Night	39% 3 10% 19% 23% 6%	3800
	11th to 20th	Night	26% 3 7% 21% 29% 14%	3779
	21st to end	Night	20% 3 7% 30% 29% 12%	4120
November	1st to 10th	Night	35% 3 8% 21% 25% 8%	2264
	11th to 20th	Night	33% 4 9% 21% 24% 8%	2384
	21st to end	Night	34% 4 8% 26% 22% 7%	2660
December	1st to 10th	Night	44% 4 8% 23% 17% 4	2660
	11th to 20th	Night	39% 4 8% 21% 21% 7%	3288
	21st to end	Night	41% 5% 11% 22% 18% 2	4596

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	26% 27% 26% 17% 4 1	270
	11th to 20th	Day	30% 21% 34% 14% 1	270
	21st to end	Day	29% 22% 33% 13% 3	297
February	1st to 10th	Day	23% 22% 37% 12% 5%	270
	11th to 20th	Day	40% 22% 29% 6% 3	270
	21st to end	Day	32% 19% 30% 16% 4	348
March	1st to 10th	Day	26% 17% 30% 21% 5%	460
	11th to 20th	Day	20% 23% 33% 19% 5%	460
	21st to end	Day	23% 17% 34% 21% 5% 1	506
April	1st to 10th	Day	22% 20% 29% 20% 7% 1	460
	11th to 20th	Day	20% 15% 29% 21% 12% 3	452
	21st to end	Day	23% 11% 32% 22% 11% 1	460
May	1st to 10th	Day	21% 13% 31% 22% 10% 3	463
	11th to 20th	Day	19% 10% 24% 26% 16% 4	487
	21st to end	Day	18% 4 22% 30% 19% 8%	529
June	1st to 10th	Day	11% 5% 26% 32% 21% 5%	490
	11th to 20th	Day	10% 6% 21% 33% 19% 10%	490
	21st to end	Day	10% 4 24% 35% 21% 7%	490
July	1st to 10th	Day	9% 4 16% 28% 30% 13%	485
	11th to 20th	Day	7% 1 14% 36% 29% 13%	484
	21st to end	Day	11% 2 18% 31% 27% 11%	532
August	1st to 10th	Day	14% 6% 16% 27% 24% 12%	486
	11th to 20th	Day	11% 3 16% 29% 27% 14%	479
	21st to end	Day	12% 2 12% 27% 27% 19%	539
September	1st to 10th	Day	13% 4 14% 27% 24% 17%	490
	11th to 20th	Day	17% 3 14% 29% 25% 12%	490
	21st to end	Day	28% 8% 19% 24% 16% 5%	490
October	1st to 10th	Day	21% 6% 17% 32% 18% 6%	490
	11th to 20th	Day	16% 12% 22% 28% 20% 3	490
	21st to end	Day	16% 10% 29% 30% 11% 4	539
November	1st to 10th	Day	18% 7% 30% 28% 13% 3	467
	11th to 20th	Day	20% 15% 27% 25% 11% 2	358
	21st to end	Day	19% 19% 26% 24% 8% 3	180
December	1st to 10th	Day	25% 15% 34% 18% 7% 1	180
	11th to 20th	Day	24% 13% 31% 25% 6% 2	180
	21st to end	Day	27% 14% 33% 18% 6% 2	276
January	1st to 10th	Night	20% 16% 36% 25% 4	760
	11th to 20th	Night	18% 18% 32% 30% 3	760
	21st to end	Night	18% 14% 41% 24% 3	836
February	1st to 10th	Night	16% 15% 38% 27% 3	760
	11th to 20th	Night	25% 17% 37% 20% 1	743
	21st to end	Night	21% 14% 38% 24% 3	628
March	1st to 10th	Night	17% 15% 36% 28% 4	760
	11th to 20th	Night	23% 13% 33% 24% 6% 1	760
	21st to end	Night	18% 12% 35% 28% 5%	836
April	1st to 10th	Night	18% 16% 35% 25% 6%	760
	11th to 20th	Night	14% 12% 32% 30% 11%	751
	21st to end	Night	17% 6% 32% 36% 8%	717
May	1st to 10th	Night	16% 9% 30% 31% 14% 1	570
	11th to 20th	Night	21% 6% 21% 34% 17% 1	561
	21st to end	Night	17% 1 13% 34% 30% 4	617
June	1st to 10th	Night	9% 2 17% 43% 28% 2	438
	11th to 20th	Night	11% 2 16% 41% 26% 3	380
	21st to end	Night	9% 2 12% 46% 29% 3	527
July	1st to 10th	Night	11% 2 10% 37% 36% 4	555
	11th to 20th	Night	7% 1 9% 33% 46% 4	552
	21st to end	Night	9% 1 8% 44% 34% 4	624
August	1st to 10th	Night	13% 3 8% 39% 31% 5%	567
	11th to 20th	Night	14% 2 6% 42% 33% 4	566
	21st to end	Night	12% 2 10% 35% 36% 5%	836
September	1st to 10th	Night	14% 2 9% 33% 36% 6%	760
	11th to 20th	Night	18% 3 11% 34% 31% 5%	760
	21st to end	Night	27% 5% 17% 29% 22% 1	760
October	1st to 10th	Night	19% 4 19% 28% 25% 5%	760
	11th to 20th	Night	16% 8% 23% 35% 17% 2	760
	21st to end	Night	16% 7% 26% 36% 14% 2	836
November	1st to 10th	Night	16% 6% 29% 34% 13% 2	755
	11th to 20th	Night	16% 11% 30% 30% 12% 1	760
	21st to end	Night	14% 11% 31% 33% 10% 1	760
December	1st to 10th	Night	23% 10% 34% 27% 6% 1	760
	11th to 20th	Night	17% 10% 35% 32% 5%	760
	21st to end	Night	21% 12% 33% 31% 4	836

Page generated at 2024-11-01 22:47:46. Version ac07

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