Easley, Liberty, Pickens Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Easley, Liberty, Pickens Area clear sky chart from 2005-11-06 to 2025-10-04.

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	13% 6% 2 6% 4 4 5% 4 6% 8% 43%	126338
	Night	15% 6% 2 6% 4 4 4 4 5% 7% 43%	123054
Transparency	Day	37% 7% 12% 20% 18% 6%	130062
	Night	38% 6% 10% 18% 21% 7%	127399
Seeing	Day	17% 8% 22% 25% 18% 9%	16287
	Night	17% 6% 22% 31% 20% 4	26302

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 2 2 3 2 4 5% 57%	4056
	11th to 20th	Day	12% 5% 2 5% 3 3 3 2 3 3 60%	4060
	21st to end	Day	20% 6% 2 6% 3 3 3 3 4 5% 46%	4466
February	1st to 10th	Day	15% 7% 3 5% 4 4 3 3 5% 6% 44%	1920
	11th to 20th	Day	22% 6% 2 5% 3 3 4 3 4 5% 43%	1948
	21st to end	Day	20% 5% 3 6% 4 5% 4 3 3 5% 43%	1650
March	1st to 10th	Day	21% 7% 2 7% 3 4 4 3 4 6% 40%	4836
	11th to 20th	Day	11% 4 2 5% 3 3 3 3 4 6% 54%	4980
	21st to end	Day	18% 6% 2 5% 4 4 4 3 4 4 46%	5465
April	1st to 10th	Day	13% 5% 1 5% 3 4 4 4 6% 8% 47%	2200
	11th to 20th	Day	12% 5% 2 5% 4 4 5% 4 5% 8% 47%	2365
	21st to end	Day	12% 4 2 4 4 4 4 5% 6% 7% 49%	2600
May	1st to 10th	Day	12% 7% 3 7% 5% 5% 5% 4 7% 8% 37%	5862
	11th to 20th	Day	18% 8% 3 7% 5% 5% 5% 4 6% 9% 30%	5861
	21st to end	Day	12% 6% 2 6% 5% 4 5% 4 7% 8% 41%	6433
June	1st to 10th	Day	10% 6% 2 7% 5% 5% 6% 6% 9% 12% 32%	2600
	11th to 20th	Day	5% 5% 2 5% 5% 6% 7% 6% 10% 12% 37%	2600
	21st to end	Day	6% 4 2 5% 6% 6% 7% 6% 9% 10% 40%	2600
July	1st to 10th	Day	6% 5% 2 6% 5% 5% 6% 5% 9% 11% 40%	5900
	11th to 20th	Day	6% 4 2 6% 5% 6% 6% 6% 9% 13% 36%	5900
	21st to end	Day	8% 7% 3 8% 6% 7% 7% 6% 9% 10% 28%	6424
August	1st to 10th	Day	13% 8% 3 7% 5% 5% 6% 5% 8% 11% 29%	4234
	11th to 20th	Day	8% 5% 2 7% 6% 5% 6% 5% 8% 11% 37%	4174
	21st to end	Day	8% 4 2 5% 4 4 5% 5% 6% 8% 51%	4259
September	1st to 10th	Day	8% 5% 3 6% 5% 5% 5% 5% 8% 9% 42%	2200
	11th to 20th	Day	13% 6% 3 7% 5% 5% 4 4 7% 8% 38%	2200
	21st to end	Day	14% 6% 3 6% 4 4 4 4 6% 8% 43%	2200
October	1st to 10th	Day	13% 5% 2 4 3 2 3 3 4 5% 55%	2104
	11th to 20th	Day	11% 5% 2 4 2 2 3 2 4 5% 59%	1900
	21st to end	Day	13% 5% 1 4 3 3 3 2 4 4 57%	2090
November	1st to 10th	Day	13% 6% 1 5% 3 2 2 3 3 5% 56%	1882
	11th to 20th	Day	14% 5% 2 4 3 3 3 3 4 6% 52%	1800
	21st to end	Day	16% 4 2 4 3 4 3 3 5% 5% 51%	1800
December	1st to 10th	Day	20% 6% 1 3 3 3 3 2 4 5% 51%	2930
	11th to 20th	Day	20% 5% 2 6% 4 4 4 3 4 6% 41%	3373
	21st to end	Day	25% 5% 1 3 3 2 3 3 4 6% 46%	4466
January	1st to 10th	Night	16% 3 1 3 2 3 3 2 3 5% 58%	5889
	11th to 20th	Night	12% 6% 1 5% 4 3 3 3 4 5% 55%	5900
	21st to end	Night	19% 6% 2 5% 3 3 2 2 4 6% 49%	6490
February	1st to 10th	Night	15% 6% 2 5% 4 4 4 3 4 5% 47%	2475
	11th to 20th	Night	22% 7% 1 5% 4 3 3 3 5% 4 44%	2338
	21st to end	Night	18% 6% 2 5% 3 3 4 4 5% 6% 44%	1980
March	1st to 10th	Night	19% 5% 2 6% 4 3 4 3 5% 6% 41%	5016
	11th to 20th	Night	10% 4 1 4 3 4 4 3 5% 7% 55%	4980
	21st to end	Night	18% 5% 2 5% 3 3 4 3 5% 7% 46%	5467
April	1st to 10th	Night	14% 5% 2 5% 4 4 4 3 5% 6% 49%	2200
	11th to 20th	Night	12% 6% 2 6% 4 3 3 3 4 7% 50%	1997
	21st to end	Night	12% 6% 2 6% 4 4 4 4 4 7% 50%	1800
May	1st to 10th	Night	13% 8% 3 8% 5% 5% 5% 4 6% 8% 35%	4033
	11th to 20th	Night	23% 8% 2 6% 5% 5% 5% 4 6% 8% 29%	4032
	21st to end	Night	14% 6% 2 6% 4 4 5% 4 6% 9% 40%	4421
June	1st to 10th	Night	8% 6% 3 8% 5% 5% 6% 5% 8% 11% 33%	1800
	11th to 20th	Night	8% 6% 2 7% 6% 4 5% 5% 8% 10% 38%	1800
	21st to end	Night	7% 6% 2 6% 5% 7% 6% 6% 8% 11% 37%	1800
July	1st to 10th	Night	11% 7% 3 9% 7% 6% 7% 5% 7% 10% 28%	4058
	11th to 20th	Night	9% 7% 3 8% 5% 6% 7% 6% 9% 12% 28%	4057
	21st to end	Night	13% 10% 4 9% 6% 6% 6% 5% 7% 10% 25%	4427
August	1st to 10th	Night	13% 8% 3 10% 7% 5% 6% 4 7% 10% 27%	2915
	11th to 20th	Night	14% 8% 3 10% 7% 6% 5% 5% 7% 9% 27%	2875
	21st to end	Night	8% 6% 3 7% 5% 5% 5% 4 6% 8% 43%	3599
September	1st to 10th	Night	10% 7% 2 8% 5% 6% 5% 4 7% 9% 38%	2200
	11th to 20th	Night	15% 7% 3 8% 4 5% 6% 4 7% 8% 35%	2200
	21st to end	Night	15% 7% 2 6% 4 5% 4 3 5% 7% 42%	2200
October	1st to 10th	Night	14% 5% 2 5% 4 3 3 3 5% 5% 51%	2143
	11th to 20th	Night	12% 4 1 5% 4 3 4 3 5% 5% 53%	2280
	21st to end	Night	14% 4 1 3 3 2 3 3 4 4 57%	2508
November	1st to 10th	Night	14% 5% 2 5% 3 3 3 2 3 5% 55%	2412
	11th to 20th	Night	16% 6% 2 4 4 2 3 2 3 6% 52%	2600
	21st to end	Night	16% 4 1 4 3 3 4 4 5% 5% 49%	2600
December	1st to 10th	Night	18% 5% 2 4 3 3 3 3 3 5% 52%	4250
	11th to 20th	Night	20% 6% 2 6% 3 3 4 3 4 4 45%	4822
	21st to end	Night	22% 5% 2 4 3 3 3 3 4 6% 45%	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% 3 5% 22% 30% 8%	4057
	11th to 20th	Day	31% 3 4 15% 39% 9%	4060
	21st to end	Day	41% 2 4 17% 24% 11%	4466
February	1st to 10th	Day	40% 3 9% 21% 20% 6%	1920
	11th to 20th	Day	44% 4 6% 18% 21% 7%	1958
	21st to end	Day	44% 5% 6% 14% 22% 8%	1650
March	1st to 10th	Day	45% 3 7% 14% 18% 13%	4836
	11th to 20th	Day	31% 4 6% 13% 26% 20%	4980
	21st to end	Day	41% 4 6% 23% 20% 6%	5465
April	1st to 10th	Day	34% 6% 11% 20% 23% 7%	2200
	11th to 20th	Day	34% 7% 8% 20% 21% 9%	2365
	21st to end	Day	33% 6% 11% 26% 19% 4	2600
May	1st to 10th	Day	42% 9% 13% 20% 13% 3	5897
	11th to 20th	Day	49% 8% 14% 18% 11% 1	5865
	21st to end	Day	38% 8% 13% 19% 19% 3	6447
June	1st to 10th	Day	39% 12% 16% 22% 8% 2	2600
	11th to 20th	Day	33% 12% 20% 22% 12% 1	2600
	21st to end	Day	34% 11% 17% 21% 14% 3	2600
July	1st to 10th	Day	35% 11% 19% 26% 8% 1	5835
	11th to 20th	Day	34% 13% 32% 17% 3 1	5831
	21st to end	Day	46% 12% 17% 19% 5%	6240
August	1st to 10th	Day	45% 10% 16% 24% 6%	4221
	11th to 20th	Day	37% 10% 22% 16% 13% 1	4213
	21st to end	Day	29% 8% 15% 26% 20% 2	4259
September	1st to 10th	Day	35% 10% 14% 19% 19% 3	2200
	11th to 20th	Day	41% 8% 13% 17% 18% 2	2200
	21st to end	Day	39% 7% 12% 18% 18% 6%	2200
October	1st to 10th	Day	27% 3 7% 18% 35% 10%	3481
	11th to 20th	Day	20% 2 6% 17% 28% 28%	3140
	21st to end	Day	28% 4 4 23% 26% 15%	3428
November	1st to 10th	Day	33% 3 8% 19% 28% 10%	1882
	11th to 20th	Day	34% 3 6% 21% 27% 8%	1800
	21st to end	Day	35% 5% 7% 22% 24% 7%	1800
December	1st to 10th	Day	37% 2 4 18% 28% 10%	2930
	11th to 20th	Day	45% 4 7% 17% 18% 9%	3370
	21st to end	Day	40% 3 8% 26% 20% 3	4466
January	1st to 10th	Night	30% 2 6% 19% 32% 10%	5889
	11th to 20th	Night	33% 3 5% 14% 35% 9%	5900
	21st to end	Night	38% 3 5% 16% 29% 10%	6490
February	1st to 10th	Night	38% 5% 8% 21% 22% 6%	2475
	11th to 20th	Night	44% 4 6% 17% 23% 7%	2339
	21st to end	Night	41% 5% 7% 16% 22% 9%	1980
March	1st to 10th	Night	42% 5% 7% 12% 27% 8%	5016
	11th to 20th	Night	28% 4 7% 13% 28% 19%	4980
	21st to end	Night	39% 4 6% 22% 21% 9%	5467
April	1st to 10th	Night	36% 4 9% 20% 25% 7%	2200
	11th to 20th	Night	34% 4 7% 23% 24% 8%	1997
	21st to end	Night	34% 6% 9% 26% 21% 4	1800
May	1st to 10th	Night	44% 8% 12% 21% 13% 1	4060
	11th to 20th	Night	51% 8% 14% 16% 11% 1	4033
	21st to end	Night	37% 8% 13% 23% 15% 2	4429
June	1st to 10th	Night	41% 12% 15% 20% 11% 2	1800
	11th to 20th	Night	37% 10% 19% 22% 12% 1	1800
	21st to end	Night	36% 14% 17% 17% 13% 4	1800
July	1st to 10th	Night	47% 11% 16% 20% 6% 1	4015
	11th to 20th	Night	44% 14% 24% 15% 2 1	4006
	21st to end	Night	52% 11% 15% 16% 5% 1	4297
August	1st to 10th	Night	49% 10% 19% 16% 5%	2904
	11th to 20th	Night	50% 11% 17% 13% 9% 1	2902
	21st to end	Night	37% 8% 14% 21% 18% 2	3599
September	1st to 10th	Night	41% 9% 13% 19% 15% 3	2200
	11th to 20th	Night	45% 9% 12% 16% 16% 2	2200
	21st to end	Night	41% 6% 11% 19% 17% 6%	2200
October	1st to 10th	Night	29% 5% 11% 13% 34% 9%	3546
	11th to 20th	Night	21% 4 5% 17% 28% 25%	3779
	21st to end	Night	28% 3 4 21% 26% 18%	4120
November	1st to 10th	Night	35% 3 7% 19% 26% 11%	2412
	11th to 20th	Night	34% 4 5% 17% 29% 10%	2600
	21st to end	Night	35% 5% 6% 20% 26% 8%	2600
December	1st to 10th	Night	36% 3 5% 19% 29% 8%	4250
	11th to 20th	Night	44% 4 8% 16% 19% 9%	4824
	21st to end	Night	41% 4 8% 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	21% 17% 38% 21% 4	300
	11th to 20th	Day	26% 17% 33% 18% 5% 1	300
	21st to end	Day	22% 16% 43% 15% 4 1	330
February	1st to 10th	Day	21% 15% 37% 20% 7%	300
	11th to 20th	Day	36% 17% 31% 14% 2	300
	21st to end	Day	29% 21% 34% 13% 3	249
March	1st to 10th	Day	22% 15% 29% 25% 9%	449
	11th to 20th	Day	19% 14% 36% 24% 6% 1	500
	21st to end	Day	24% 17% 30% 21% 7% 1	550
April	1st to 10th	Day	20% 15% 28% 26% 10% 2	500
	11th to 20th	Day	14% 13% 33% 25% 13% 2	492
	21st to end	Day	18% 8% 25% 27% 16% 6%	500
May	1st to 10th	Day	13% 11% 29% 28% 13% 6%	503
	11th to 20th	Day	19% 7% 20% 27% 19% 8%	527
	21st to end	Day	16% 7% 20% 23% 21% 13%	573
June	1st to 10th	Day	13% 5% 15% 31% 26% 11%	530
	11th to 20th	Day	7% 6% 17% 26% 26% 19%	530
	21st to end	Day	10% 2 15% 28% 26% 19%	530
July	1st to 10th	Day	9% 2 11% 24% 30% 25%	525
	11th to 20th	Day	8% 1 8% 24% 33% 27%	524
	21st to end	Day	7% 3 7% 30% 31% 22%	576
August	1st to 10th	Day	18% 3 13% 24% 24% 18%	526
	11th to 20th	Day	11% 3 9% 28% 32% 17%	519
	21st to end	Day	13% 2 13% 24% 26% 22%	583
September	1st to 10th	Day	10% 2 14% 28% 32% 15%	530
	11th to 20th	Day	16% 3 15% 21% 28% 17%	530
	21st to end	Day	19% 4 18% 27% 23% 8%	530
October	1st to 10th	Day	18% 4 17% 30% 21% 11%	502
	11th to 20th	Day	12% 9% 19% 34% 22% 4	490
	21st to end	Day	18% 6% 21% 31% 20% 4	539
November	1st to 10th	Day	21% 7% 25% 27% 16% 4	420
	11th to 20th	Day	18% 14% 30% 29% 7% 1	300
	21st to end	Day	11% 13% 33% 30% 10% 3	300
December	1st to 10th	Day	28% 14% 28% 23% 7%	300
	11th to 20th	Day	25% 10% 34% 23% 8% 1	300
	21st to end	Day	31% 13% 26% 22% 6% 2	330
January	1st to 10th	Night	21% 10% 32% 32% 6%	800
	11th to 20th	Night	20% 12% 30% 32% 6%	800
	21st to end	Night	20% 12% 35% 30% 3	880
February	1st to 10th	Night	18% 10% 30% 38% 4	800
	11th to 20th	Night	26% 8% 34% 28% 3	783
	21st to end	Night	19% 14% 32% 32% 3	660
March	1st to 10th	Night	19% 8% 31% 35% 6%	800
	11th to 20th	Night	17% 8% 36% 31% 8% 1	800
	21st to end	Night	19% 9% 30% 33% 9%	880
April	1st to 10th	Night	16% 12% 28% 34% 10%	800
	11th to 20th	Night	15% 10% 26% 34% 14% 1	698
	21st to end	Night	13% 5% 23% 38% 20% 1	600
May	1st to 10th	Night	14% 5% 22% 38% 21% 1	600
	11th to 20th	Night	17% 5% 18% 33% 24% 3	591
	21st to end	Night	17% 1 13% 27% 36% 6%	650
June	1st to 10th	Night	12% 2 13% 34% 34% 5%	600
	11th to 20th	Night	11% 3 14% 26% 34% 13%	600
	21st to end	Night	8% 2 12% 31% 39% 8%	600
July	1st to 10th	Night	13% 2 8% 23% 40% 14%	585
	11th to 20th	Night	10% 2 5% 23% 42% 16%	582
	21st to end	Night	11% 1 9% 23% 44% 12%	657
August	1st to 10th	Night	16% 3 10% 22% 37% 12%	597
	11th to 20th	Night	15% 2 9% 24% 39% 9%	594
	21st to end	Night	14% 1 10% 25% 40% 10%	716
September	1st to 10th	Night	12% 3 12% 28% 36% 10%	800
	11th to 20th	Night	18% 4 13% 25% 34% 7%	800
	21st to end	Night	17% 3 16% 31% 29% 3	800
October	1st to 10th	Night	16% 5% 16% 29% 28% 6%	773
	11th to 20th	Night	16% 4 20% 36% 22% 3	760
	21st to end	Night	15% 5% 20% 36% 19% 4	836
November	1st to 10th	Night	16% 5% 21% 35% 19% 4	780
	11th to 20th	Night	19% 7% 27% 34% 12% 2	800
	21st to end	Night	18% 6% 24% 38% 14% 1	800
December	1st to 10th	Night	24% 7% 23% 36% 9% 1	800
	11th to 20th	Night	20% 6% 29% 35% 11% 1	800
	21st to end	Night	25% 10% 24% 33% 8%	880

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