Lake Wateree State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Wateree State Park clear sky chart from 2005-11-06 to 2025-12-18.

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% 42%	127176
	Night	14% 6% 2 6% 4 4 4 4 6% 7% 44%	123864
Transparency	Day	38% 7% 12% 19% 18% 6%	130822
	Night	38% 6% 10% 18% 20% 7%	128287
Seeing	Day	16% 10% 26% 24% 18% 6%	16840
	Night	16% 9% 25% 31% 18% 2	26917

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 5% 3 3 2 2 4 5% 55%	4056
	11th to 20th	Day	12% 5% 2 4 3 3 3 2 3 4 59%	4060
	21st to end	Day	16% 8% 2 6% 4 4 3 3 4 4 45%	4466
February	1st to 10th	Day	14% 8% 3 5% 4 4 4 3 5% 8% 42%	1800
	11th to 20th	Day	22% 6% 2 5% 2 3 3 3 4 5% 44%	1933
	21st to end	Day	19% 7% 3 5% 4 4 3 3 4 5% 44%	1720
March	1st to 10th	Day	21% 7% 3 7% 4 4 3 2 4 5% 40%	4935
	11th to 20th	Day	8% 4 2 6% 4 4 4 3 5% 6% 54%	4980
	21st to end	Day	15% 6% 2 6% 4 4 4 2 4 5% 48%	5465
April	1st to 10th	Day	10% 4 1 5% 4 4 5% 4 6% 8% 49%	2200
	11th to 20th	Day	10% 5% 2 6% 4 4 4 4 6% 7% 49%	2364
	21st to end	Day	10% 5% 2 5% 4 4 4 4 5% 7% 50%	2514
May	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 4 7% 10% 39%	5862
	11th to 20th	Day	18% 6% 3 7% 5% 5% 6% 4 7% 9% 31%	5861
	21st to end	Day	11% 6% 2 7% 4 4 5% 4 5% 7% 45%	6433
June	1st to 10th	Day	9% 6% 2 8% 5% 5% 5% 5% 8% 11% 36%	2600
	11th to 20th	Day	8% 4 1 6% 4 6% 6% 5% 8% 11% 42%	2600
	21st to end	Day	5% 5% 2 6% 6% 6% 6% 6% 9% 11% 39%	2600
July	1st to 10th	Day	10% 7% 3 8% 6% 6% 7% 6% 8% 10% 29%	5900
	11th to 20th	Day	6% 5% 2 6% 6% 7% 8% 6% 10% 14% 30%	5900
	21st to end	Day	8% 7% 3 8% 6% 6% 6% 6% 9% 13% 28%	6424
August	1st to 10th	Day	23% 7% 3 7% 4 5% 6% 5% 7% 9% 22%	4234
	11th to 20th	Day	11% 6% 2 7% 5% 5% 6% 5% 8% 11% 34%	4174
	21st to end	Day	7% 3 2 4 4 4 5% 4 8% 11% 48%	4345
September	1st to 10th	Day	8% 5% 2 7% 5% 5% 5% 4 7% 10% 42%	2222
	11th to 20th	Day	13% 6% 3 7% 4 6% 4 4 6% 8% 39%	2200
	21st to end	Day	18% 7% 2 5% 4 4 4 3 6% 7% 41%	2200
October	1st to 10th	Day	16% 5% 1 4 4 3 4 3 5% 5% 50%	2075
	11th to 20th	Day	12% 4 2 5% 4 3 2 2 4 5% 58%	2000
	21st to end	Day	13% 5% 2 4 3 3 3 2 3 5% 57%	2200
November	1st to 10th	Day	14% 5% 1 4 3 3 3 3 4 5% 54%	2057
	11th to 20th	Day	14% 5% 1 4 3 2 2 2 4 6% 56%	1984
	21st to end	Day	14% 5% 2 5% 3 3 3 3 5% 7% 50%	1890
December	1st to 10th	Day	13% 6% 2 5% 4 3 4 3 4 5% 51%	3020
	11th to 20th	Day	15% 7% 3 6% 3 3 4 3 5% 6% 45%	3436
	21st to end	Day	20% 7% 2 4 3 3 3 3 4 6% 46%	4466
January	1st to 10th	Night	12% 4 2 5% 3 3 3 3 3 4 58%	5889
	11th to 20th	Night	12% 5% 2 5% 4 4 4 3 4 5% 52%	5900
	21st to end	Night	15% 9% 2 6% 4 4 3 3 4 5% 46%	6490
February	1st to 10th	Night	15% 6% 2 5% 4 3 4 3 6% 5% 46%	2600
	11th to 20th	Night	20% 5% 3 5% 4 4 4 3 4 5% 43%	2348
	21st to end	Night	14% 6% 2 5% 4 3 4 3 5% 8% 46%	1910
March	1st to 10th	Night	20% 7% 2 6% 4 4 3 3 5% 6% 40%	4918
	11th to 20th	Night	11% 4 2 4 3 3 4 3 5% 6% 55%	4980
	21st to end	Night	15% 4 2 5% 4 4 4 3 5% 7% 48%	5467
April	1st to 10th	Night	11% 6% 2 5% 4 4 4 4 5% 6% 50%	2200
	11th to 20th	Night	10% 5% 2 5% 4 3 4 3 5% 7% 52%	1984
	21st to end	Night	10% 4 2 5% 4 3 4 3 5% 7% 51%	1901
May	1st to 10th	Night	11% 6% 3 6% 5% 4 5% 4 6% 9% 41%	4033
	11th to 20th	Night	19% 6% 2 6% 4 5% 5% 4 7% 8% 33%	4032
	21st to end	Night	13% 5% 2 5% 4 4 5% 5% 7% 8% 42%	4421
June	1st to 10th	Night	11% 7% 3 7% 6% 6% 6% 5% 7% 10% 34%	1800
	11th to 20th	Night	9% 6% 2 6% 5% 6% 6% 5% 7% 11% 37%	1800
	21st to end	Night	7% 5% 2 7% 6% 5% 7% 6% 9% 11% 36%	1800
July	1st to 10th	Night	11% 7% 3 10% 6% 6% 7% 5% 8% 10% 26%	4058
	11th to 20th	Night	8% 5% 2 7% 6% 6% 8% 6% 11% 14% 26%	4057
	21st to end	Night	11% 9% 4 11% 7% 7% 7% 5% 8% 10% 22%	4427
August	1st to 10th	Night	24% 8% 3 8% 5% 5% 5% 4 7% 9% 23%	2915
	11th to 20th	Night	11% 7% 2 7% 5% 5% 6% 5% 8% 10% 33%	2875
	21st to end	Night	6% 4 2 5% 3 4 4 4 7% 11% 50%	3517
September	1st to 10th	Night	9% 5% 2 6% 5% 5% 4 4 7% 9% 42%	2173
	11th to 20th	Night	14% 6% 2 8% 6% 4 5% 3 5% 6% 41%	2200
	21st to end	Night	17% 7% 2 6% 4 4 4 4 5% 6% 42%	2200
October	1st to 10th	Night	14% 6% 2 5% 2 3 3 3 3 6% 53%	2324
	11th to 20th	Night	15% 5% 1 4 3 3 3 2 3 6% 56%	2400
	21st to end	Night	12% 5% 1 4 3 3 3 3 4 4 57%	2640
November	1st to 10th	Night	13% 6% 2 4 3 3 3 3 3 6% 54%	2461
	11th to 20th	Night	13% 6% 2 5% 4 3 3 3 4 5% 54%	2630
	21st to end	Night	13% 5% 2 4 4 4 3 3 6% 7% 49%	2730
December	1st to 10th	Night	14% 6% 2 5% 3 4 3 3 4 5% 53%	4380
	11th to 20th	Night	17% 7% 3 6% 3 3 3 3 5% 6% 45%	4914
	21st to end	Night	19% 6% 2 6% 4 4 3 3 5% 5% 44%	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% 20% 32% 7%	4057
	11th to 20th	Day	31% 3 4 15% 37% 10%	4060
	21st to end	Day	43% 3 4 18% 22% 10%	4466
February	1st to 10th	Day	42% 4 9% 21% 19% 6%	1800
	11th to 20th	Day	43% 4 6% 17% 24% 6%	1943
	21st to end	Day	43% 4 8% 16% 21% 8%	1720
March	1st to 10th	Day	47% 4 6% 13% 19% 11%	4935
	11th to 20th	Day	31% 4 7% 13% 27% 18%	4980
	21st to end	Day	40% 4 6% 20% 22% 7%	5465
April	1st to 10th	Day	32% 5% 11% 20% 26% 6%	2200
	11th to 20th	Day	33% 7% 10% 20% 20% 11%	2364
	21st to end	Day	33% 6% 12% 24% 22% 4	2514
May	1st to 10th	Day	39% 7% 17% 24% 11% 1	5897
	11th to 20th	Day	48% 8% 15% 17% 12% 1	5865
	21st to end	Day	37% 7% 13% 20% 20% 4	6447
June	1st to 10th	Day	39% 9% 16% 24% 10% 2	2600
	11th to 20th	Day	33% 10% 19% 23% 14% 2	2600
	21st to end	Day	34% 12% 17% 21% 14% 2	2600
July	1st to 10th	Day	45% 12% 18% 19% 6% 1	5835
	11th to 20th	Day	36% 17% 30% 14% 3 1	5831
	21st to end	Day	43% 14% 17% 20% 6% 1	6240
August	1st to 10th	Day	55% 9% 18% 14% 4	4221
	11th to 20th	Day	39% 12% 16% 19% 12% 1	4213
	21st to end	Day	27% 9% 16% 31% 15% 2	4345
September	1st to 10th	Day	35% 10% 15% 18% 18% 4	2222
	11th to 20th	Day	41% 8% 12% 17% 19% 3	2200
	21st to end	Day	42% 5% 10% 21% 14% 7%	2200
October	1st to 10th	Day	31% 5% 7% 20% 27% 9%	3374
	11th to 20th	Day	21% 2 4 18% 28% 27%	3240
	21st to end	Day	27% 3 5% 22% 29% 15%	3538
November	1st to 10th	Day	32% 4 7% 17% 29% 11%	2057
	11th to 20th	Day	31% 3 8% 21% 27% 10%	1984
	21st to end	Day	35% 5% 8% 21% 23% 8%	1890
December	1st to 10th	Day	37% 4 6% 18% 27% 9%	3020
	11th to 20th	Day	40% 4 11% 19% 19% 7%	3433
	21st to end	Day	41% 3 8% 23% 23% 2	4466
January	1st to 10th	Night	31% 4 5% 18% 36% 7%	5889
	11th to 20th	Night	34% 4 6% 15% 33% 7%	5900
	21st to end	Night	42% 3 3 15% 28% 8%	6490
February	1st to 10th	Night	39% 5% 8% 20% 20% 8%	2600
	11th to 20th	Night	44% 5% 7% 16% 22% 7%	2349
	21st to end	Night	38% 4 10% 17% 22% 10%	1910
March	1st to 10th	Night	44% 5% 7% 13% 24% 7%	4918
	11th to 20th	Night	29% 5% 7% 13% 28% 19%	4980
	21st to end	Night	36% 4 7% 21% 21% 11%	5467
April	1st to 10th	Night	33% 6% 10% 20% 23% 8%	2200
	11th to 20th	Night	32% 5% 10% 21% 22% 11%	1984
	21st to end	Night	31% 5% 12% 27% 20% 5%	1901
May	1st to 10th	Night	38% 7% 15% 24% 14% 2	4060
	11th to 20th	Night	46% 9% 16% 19% 11% 1	4033
	21st to end	Night	35% 9% 14% 24% 17% 2	4429
June	1st to 10th	Night	42% 10% 15% 21% 11% 1	1800
	11th to 20th	Night	38% 11% 18% 21% 11% 2	1800
	21st to end	Night	36% 14% 17% 20% 11% 2	1800
July	1st to 10th	Night	48% 13% 20% 14% 5% 1	4015
	11th to 20th	Night	41% 19% 26% 10% 3 1	4006
	21st to end	Night	53% 13% 15% 14% 5%	4297
August	1st to 10th	Night	56% 9% 17% 14% 3 1	2904
	11th to 20th	Night	41% 12% 20% 19% 6% 1	2902
	21st to end	Night	28% 8% 15% 29% 18% 3	3517
September	1st to 10th	Night	35% 9% 15% 20% 15% 5%	2173
	11th to 20th	Night	43% 7% 12% 16% 20% 2	2200
	21st to end	Night	42% 7% 12% 18% 16% 5%	2200
October	1st to 10th	Night	32% 5% 9% 20% 27% 6%	3805
	11th to 20th	Night	22% 3 5% 16% 27% 27%	3899
	21st to end	Night	26% 4 6% 19% 27% 18%	4252
November	1st to 10th	Night	33% 3 8% 16% 27% 13%	2461
	11th to 20th	Night	33% 4 6% 17% 27% 12%	2630
	21st to end	Night	34% 5% 7% 20% 25% 9%	2730
December	1st to 10th	Night	35% 3 7% 18% 29% 8%	4380
	11th to 20th	Night	41% 5% 10% 16% 19% 9%	4916
	21st to end	Night	42% 4 7% 24% 20% 2	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	19% 25% 43% 10% 2	300
	11th to 20th	Day	22% 21% 37% 17% 4	300
	21st to end	Day	22% 24% 37% 15% 2	330
February	1st to 10th	Day	17% 24% 42% 12% 5%	300
	11th to 20th	Day	35% 16% 41% 7% 2	300
	21st to end	Day	22% 21% 37% 16% 4	319
March	1st to 10th	Day	22% 18% 34% 19% 7%	500
	11th to 20th	Day	21% 18% 40% 17% 4 1	500
	21st to end	Day	21% 18% 37% 18% 6% 1	550
April	1st to 10th	Day	19% 17% 35% 18% 10% 1	500
	11th to 20th	Day	13% 16% 33% 26% 10% 3	492
	21st to end	Day	14% 11% 29% 27% 16% 3	500
May	1st to 10th	Day	11% 15% 36% 23% 11% 4	503
	11th to 20th	Day	18% 7% 23% 27% 18% 7%	527
	21st to end	Day	16% 7% 19% 27% 21% 10%	573
June	1st to 10th	Day	11% 4 21% 34% 23% 7%	530
	11th to 20th	Day	9% 4 19% 28% 28% 12%	530
	21st to end	Day	8% 1 15% 33% 32% 11%	530
July	1st to 10th	Day	9% 1 13% 24% 34% 19%	525
	11th to 20th	Day	9% 2 9% 29% 35% 16%	524
	21st to end	Day	8% 2 11% 34% 33% 12%	576
August	1st to 10th	Day	17% 5% 15% 25% 26% 12%	526
	11th to 20th	Day	13% 3 13% 27% 29% 14%	519
	21st to end	Day	13% 2 14% 30% 26% 15%	583
September	1st to 10th	Day	11% 3 14% 32% 30% 11%	530
	11th to 20th	Day	16% 3 14% 27% 30% 10%	530
	21st to end	Day	20% 5% 17% 29% 22% 7%	530
October	1st to 10th	Day	16% 5% 22% 29% 21% 7%	530
	11th to 20th	Day	12% 10% 24% 29% 21% 5%	530
	21st to end	Day	16% 8% 26% 27% 18% 5%	583
November	1st to 10th	Day	19% 9% 29% 26% 15% 3	535
	11th to 20th	Day	18% 14% 36% 22% 8% 2	424
	21st to end	Day	12% 15% 40% 23% 8% 1	330
December	1st to 10th	Day	26% 16% 39% 16% 3	330
	11th to 20th	Day	21% 13% 35% 22% 7% 2	321
	21st to end	Day	27% 15% 35% 15% 7% 2	330
January	1st to 10th	Night	22% 16% 31% 26% 5%	800
	11th to 20th	Night	19% 15% 32% 29% 5%	800
	21st to end	Night	19% 16% 35% 27% 3	880
February	1st to 10th	Night	19% 13% 33% 31% 4	800
	11th to 20th	Night	24% 14% 38% 22% 1	783
	21st to end	Night	17% 17% 36% 25% 4	660
March	1st to 10th	Night	18% 13% 37% 26% 5%	800
	11th to 20th	Night	18% 14% 36% 25% 8%	800
	21st to end	Night	17% 14% 38% 24% 7%	880
April	1st to 10th	Night	14% 16% 34% 27% 8%	800
	11th to 20th	Night	13% 14% 29% 31% 12% 1	791
	21st to end	Night	14% 7% 31% 36% 12%	701
May	1st to 10th	Night	11% 8% 30% 38% 12% 1	600
	11th to 20th	Night	13% 6% 27% 37% 16% 1	591
	21st to end	Night	12% 4 16% 33% 31% 4	650
June	1st to 10th	Night	13% 5% 16% 38% 24% 4	600
	11th to 20th	Night	10% 3 16% 35% 29% 7%	600
	21st to end	Night	9% 2 15% 38% 31% 6%	600
July	1st to 10th	Night	10% 1 9% 36% 35% 8%	585
	11th to 20th	Night	10% 1 6% 35% 40% 8%	582
	21st to end	Night	7% 4 11% 33% 39% 6%	657
August	1st to 10th	Night	14% 3 12% 28% 38% 5%	597
	11th to 20th	Night	13% 3 9% 32% 36% 7%	594
	21st to end	Night	12% 3 11% 30% 38% 6%	837
September	1st to 10th	Night	10% 3 12% 33% 37% 5%	800
	11th to 20th	Night	17% 3 14% 30% 33% 4	800
	21st to end	Night	20% 4 15% 34% 24% 3	800
October	1st to 10th	Night	16% 4 20% 30% 26% 4	800
	11th to 20th	Night	17% 6% 25% 30% 21% 2	800
	21st to end	Night	14% 8% 24% 31% 21% 2	880
November	1st to 10th	Night	15% 8% 26% 33% 15% 4	820
	11th to 20th	Night	16% 11% 29% 32% 10% 1	840
	21st to end	Night	15% 10% 29% 32% 14% 1	840
December	1st to 10th	Night	20% 12% 30% 30% 7%	840
	11th to 20th	Night	19% 10% 28% 32% 11% 1	829
	21st to end	Night	24% 13% 26% 28% 8%	880

Page generated at 2025-12-15 01:13:53. Version ac07

Copyright © 2025 Attilla Danko.