Aynor, SC
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Aynor, SC clear sky chart from 2005-11-06 to 2026-02-01.

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 7% 5% 5% 5% 4 6% 8% 40%	127435
	Night	12% 6% 2 6% 4 4 4 4 6% 8% 44%	124621
Transparency	Day	40% 6% 13% 19% 17% 6%	131038
	Night	38% 5% 12% 19% 19% 7%	129087
Seeing	Day	15% 7% 23% 25% 19% 10%	17292
	Night	14% 6% 22% 34% 21% 3	27437

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	13% 6% 2 4 4 3 3 2 4 6% 54%	4146
	11th to 20th	Day	11% 6% 2 5% 4 3 3 3 4 6% 54%	4150
	21st to end	Day	14% 9% 3 6% 4 4 4 3 4 6% 43%	4565
February	1st to 10th	Day	16% 7% 3 7% 5% 4 4 4 6% 5% 42%	1800
	11th to 20th	Day	19% 6% 2 5% 3 3 4 3 4 5% 45%	1837
	21st to end	Day	15% 5% 3 7% 4 4 4 3 5% 7% 43%	1815
March	1st to 10th	Day	20% 8% 3 6% 4 4 3 3 5% 5% 38%	4935
	11th to 20th	Day	9% 5% 2 5% 3 4 4 3 5% 7% 54%	4980
	21st to end	Day	12% 5% 2 6% 4 4 4 3 5% 5% 49%	5465
April	1st to 10th	Day	9% 4 2 4 4 4 4 4 6% 7% 51%	2295
	11th to 20th	Day	9% 5% 2 5% 4 3 5% 4 6% 7% 51%	2374
	21st to end	Day	8% 4 2 4 4 5% 5% 4 7% 8% 50%	2400
May	1st to 10th	Day	10% 6% 2 8% 5% 5% 5% 5% 7% 9% 37%	5669
	11th to 20th	Day	16% 7% 3 8% 5% 5% 5% 5% 7% 9% 30%	5861
	21st to end	Day	10% 5% 2 6% 4 5% 5% 5% 6% 9% 42%	6433
June	1st to 10th	Day	9% 7% 3 7% 6% 6% 6% 5% 7% 10% 33%	2600
	11th to 20th	Day	9% 5% 2 7% 5% 6% 6% 5% 7% 10% 38%	2600
	21st to end	Day	7% 6% 2 7% 6% 5% 6% 6% 9% 12% 34%	2600
July	1st to 10th	Day	10% 8% 3 9% 6% 6% 7% 6% 9% 12% 24%	5900
	11th to 20th	Day	7% 5% 3 8% 7% 8% 8% 7% 11% 13% 25%	5900
	21st to end	Day	9% 7% 3 9% 7% 6% 8% 6% 8% 11% 24%	6424
August	1st to 10th	Day	22% 9% 3 9% 6% 5% 6% 5% 7% 9% 19%	4234
	11th to 20th	Day	10% 7% 3 8% 5% 6% 7% 5% 7% 11% 30%	3983
	21st to end	Day	8% 6% 3 7% 5% 6% 6% 4 7% 11% 37%	4312
September	1st to 10th	Day	9% 6% 2 8% 5% 6% 6% 4 7% 10% 38%	2400
	11th to 20th	Day	14% 8% 3 7% 5% 4 5% 4 5% 8% 37%	2221
	21st to end	Day	16% 7% 3 8% 4 4 4 4 5% 8% 36%	2173
October	1st to 10th	Day	14% 7% 2 6% 4 4 5% 4 5% 6% 44%	2000
	11th to 20th	Day	11% 4 2 5% 3 3 4 2 4 6% 57%	2000
	21st to end	Day	11% 5% 2 4 4 3 4 3 4 6% 56%	2200
November	1st to 10th	Day	12% 5% 2 5% 3 3 3 4 4 5% 55%	2057
	11th to 20th	Day	14% 5% 2 5% 4 3 3 2 4 5% 52%	2100
	21st to end	Day	12% 6% 2 5% 3 3 4 3 5% 6% 51%	1958
December	1st to 10th	Day	10% 5% 2 6% 4 4 4 3 5% 6% 51%	3020
	11th to 20th	Day	15% 6% 2 6% 3 3 4 3 4 6% 46%	3463
	21st to end	Day	15% 7% 2 6% 4 4 4 3 5% 6% 45%	4565
January	1st to 10th	Night	11% 6% 2 5% 3 3 3 3 4 5% 55%	6019
	11th to 20th	Night	12% 6% 2 5% 4 4 4 3 5% 7% 48%	6030
	21st to end	Night	13% 7% 3 7% 4 4 4 3 4 5% 46%	6633
February	1st to 10th	Night	16% 6% 2 6% 4 4 3 3 5% 6% 44%	2601
	11th to 20th	Night	18% 7% 2 6% 4 3 4 4 4 6% 42%	2443
	21st to end	Night	14% 5% 2 6% 4 5% 4 4 5% 6% 46%	1815
March	1st to 10th	Night	19% 11% 3 6% 4 4 3 3 4 5% 39%	4918
	11th to 20th	Night	11% 5% 2 5% 3 3 4 3 5% 9% 50%	4980
	21st to end	Night	12% 4 2 5% 4 4 4 3 4 6% 52%	5467
April	1st to 10th	Night	10% 6% 2 6% 5% 4 4 4 5% 7% 48%	2105
	11th to 20th	Night	10% 4 2 6% 4 3 4 3 6% 7% 51%	1975
	21st to end	Night	8% 4 1 5% 5% 4 4 3 6% 8% 52%	2000
May	1st to 10th	Night	6% 7% 2 6% 4 4 5% 4 7% 11% 43%	4268
	11th to 20th	Night	15% 6% 2 7% 4 4 4 4 6% 11% 36%	4032
	21st to end	Night	11% 6% 2 6% 4 4 5% 4 7% 9% 42%	4421
June	1st to 10th	Night	9% 6% 2 7% 5% 5% 5% 5% 8% 11% 37%	1800
	11th to 20th	Night	9% 5% 2 6% 5% 5% 6% 5% 8% 11% 40%	1800
	21st to end	Night	6% 5% 2 7% 7% 5% 6% 5% 8% 13% 36%	1800
July	1st to 10th	Night	10% 6% 3 8% 6% 6% 7% 6% 7% 10% 31%	4058
	11th to 20th	Night	7% 6% 3 7% 5% 5% 6% 5% 9% 15% 30%	4057
	21st to end	Night	9% 7% 3 9% 6% 6% 6% 5% 9% 11% 29%	4427
August	1st to 10th	Night	19% 9% 3 8% 4 5% 5% 4 8% 10% 25%	2915
	11th to 20th	Night	7% 6% 3 8% 5% 6% 6% 5% 7% 9% 38%	3030
	21st to end	Night	7% 5% 2 6% 5% 4 5% 4 8% 9% 45%	3586
September	1st to 10th	Night	9% 5% 2 6% 5% 5% 5% 5% 8% 10% 42%	2000
	11th to 20th	Night	13% 7% 2 8% 4 5% 5% 4 5% 5% 42%	2173
	21st to end	Night	16% 7% 3 7% 4 4 4 3 4 7% 41%	2225
October	1st to 10th	Night	12% 7% 2 6% 4 4 3 3 4 7% 48%	2400
	11th to 20th	Night	11% 4 2 4 4 3 3 2 4 5% 58%	2400
	21st to end	Night	10% 4 2 5% 3 3 3 3 4 6% 56%	2640
November	1st to 10th	Night	12% 5% 1 5% 4 3 3 3 4 5% 56%	2461
	11th to 20th	Night	14% 7% 2 5% 3 3 2 2 5% 6% 51%	2520
	21st to end	Night	10% 5% 2 5% 4 3 3 4 6% 8% 48%	2657
December	1st to 10th	Night	12% 6% 2 5% 4 3 3 3 4 5% 53%	4380
	11th to 20th	Night	16% 8% 3 7% 4 3 3 3 4 5% 44%	4952
	21st to end	Night	14% 7% 2 6% 4 4 4 3 5% 6% 44%	6633

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	33% 3 6% 17% 34% 8%	4147
	11th to 20th	Day	33% 2 4 17% 34% 10%	4150
	21st to end	Day	44% 4 5% 16% 21% 11%	4565
February	1st to 10th	Day	44% 3 8% 20% 20% 5%	1800
	11th to 20th	Day	43% 3 6% 18% 21% 9%	1846
	21st to end	Day	40% 4 9% 19% 20% 8%	1815
March	1st to 10th	Day	49% 3 7% 13% 20% 9%	4935
	11th to 20th	Day	31% 3 8% 15% 28% 15%	4980
	21st to end	Day	38% 4 9% 18% 21% 10%	5465
April	1st to 10th	Day	31% 4 12% 21% 25% 7%	2295
	11th to 20th	Day	31% 4 10% 24% 20% 11%	2374
	21st to end	Day	31% 4 12% 25% 23% 4	2400
May	1st to 10th	Day	40% 7% 18% 25% 8% 1	5701
	11th to 20th	Day	48% 7% 14% 19% 11% 1	5865
	21st to end	Day	37% 6% 14% 21% 19% 3	6447
June	1st to 10th	Day	43% 7% 15% 23% 11% 1	2600
	11th to 20th	Day	38% 7% 20% 21% 13% 1	2600
	21st to end	Day	38% 10% 19% 23% 9% 1	2600
July	1st to 10th	Day	48% 10% 23% 15% 3 1	5835
	11th to 20th	Day	45% 13% 30% 9% 3	5831
	21st to end	Day	49% 11% 16% 18% 6%	6240
August	1st to 10th	Day	61% 8% 17% 11% 3	4221
	11th to 20th	Day	44% 9% 18% 20% 9%	4022
	21st to end	Day	38% 7% 16% 31% 7% 1	4312
September	1st to 10th	Day	40% 8% 16% 18% 14% 5%	2400
	11th to 20th	Day	46% 5% 10% 17% 17% 4	2221
	21st to end	Day	47% 5% 10% 19% 15% 3	2173
October	1st to 10th	Day	40% 5% 8% 19% 23% 5%	3260
	11th to 20th	Day	21% 2 5% 16% 29% 27%	3240
	21st to end	Day	27% 3 5% 19% 34% 11%	3538
November	1st to 10th	Day	32% 3 8% 19% 27% 11%	2057
	11th to 20th	Day	36% 2 7% 18% 26% 10%	2100
	21st to end	Day	34% 4 9% 20% 25% 8%	1958
December	1st to 10th	Day	34% 4 8% 16% 23% 15%	3020
	11th to 20th	Day	39% 4 9% 23% 20% 6%	3460
	21st to end	Day	41% 3 10% 22% 21% 3	4565
January	1st to 10th	Night	33% 3 5% 17% 35% 7%	6019
	11th to 20th	Night	36% 3 6% 15% 32% 7%	6030
	21st to end	Night	42% 3 5% 13% 26% 10%	6633
February	1st to 10th	Night	41% 3 7% 20% 20% 8%	2601
	11th to 20th	Night	44% 3 8% 17% 20% 8%	2445
	21st to end	Night	39% 4 10% 19% 19% 11%	1815
March	1st to 10th	Night	49% 3 7% 12% 23% 6%	4918
	11th to 20th	Night	32% 4 8% 12% 26% 17%	4980
	21st to end	Night	35% 3 10% 22% 20% 10%	5467
April	1st to 10th	Night	35% 3 12% 19% 22% 9%	2105
	11th to 20th	Night	32% 4 11% 23% 19% 11%	1975
	21st to end	Night	30% 4 14% 26% 22% 4	2000
May	1st to 10th	Night	35% 5% 21% 26% 11% 2	4298
	11th to 20th	Night	42% 7% 19% 20% 12%	4033
	21st to end	Night	36% 8% 15% 22% 17% 1	4429
June	1st to 10th	Night	39% 9% 17% 24% 10% 1	1800
	11th to 20th	Night	36% 7% 21% 24% 10% 1	1800
	21st to end	Night	37% 9% 22% 23% 7% 1	1800
July	1st to 10th	Night	46% 9% 26% 15% 4 1	4015
	11th to 20th	Night	41% 12% 36% 8% 3	4006
	21st to end	Night	46% 11% 16% 22% 4	4297
August	1st to 10th	Night	53% 7% 23% 14% 2	2904
	11th to 20th	Night	39% 10% 21% 24% 7%	3057
	21st to end	Night	33% 6% 18% 33% 10%	3586
September	1st to 10th	Night	36% 8% 20% 20% 13% 5%	2000
	11th to 20th	Night	42% 7% 13% 19% 16% 3	2173
	21st to end	Night	45% 4 13% 22% 13% 4	2225
October	1st to 10th	Night	36% 4 9% 20% 25% 5%	3920
	11th to 20th	Night	21% 2 5% 14% 26% 33%	3899
	21st to end	Night	25% 3 6% 23% 28% 15%	4252
November	1st to 10th	Night	32% 2 9% 17% 26% 13%	2461
	11th to 20th	Night	36% 2 8% 16% 26% 12%	2520
	21st to end	Night	34% 4 9% 22% 23% 9%	2657
December	1st to 10th	Night	36% 2 7% 14% 28% 13%	4380
	11th to 20th	Night	43% 4 11% 16% 18% 8%	4954
	21st to end	Night	40% 4 9% 22% 22% 3	6633

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	20% 15% 41% 18% 5% 1	330
	11th to 20th	Day	15% 18% 37% 20% 10% 1	330
	21st to end	Day	21% 18% 38% 18% 4 1	363
February	1st to 10th	Day	20% 13% 38% 22% 6% 1	300
	11th to 20th	Day	30% 13% 35% 18% 4	338
	21st to end	Day	18% 13% 39% 21% 9%	414
March	1st to 10th	Day	17% 15% 34% 23% 9% 1	500
	11th to 20th	Day	17% 13% 39% 22% 9% 1	500
	21st to end	Day	15% 12% 39% 22% 9% 2	550
April	1st to 10th	Day	14% 16% 32% 25% 11% 2	500
	11th to 20th	Day	11% 12% 30% 23% 16% 8%	492
	21st to end	Day	9% 8% 27% 29% 19% 9%	500
May	1st to 10th	Day	9% 12% 29% 26% 15% 9%	503
	11th to 20th	Day	15% 4 20% 29% 21% 10%	527
	21st to end	Day	16% 4 16% 26% 23% 16%	573
June	1st to 10th	Day	11% 2 16% 31% 26% 13%	530
	11th to 20th	Day	10% 2 15% 25% 28% 19%	530
	21st to end	Day	8% 1 10% 30% 32% 18%	530
July	1st to 10th	Day	9% 1 6% 27% 34% 23%	525
	11th to 20th	Day	9% 5% 23% 36% 27%	524
	21st to end	Day	8% 2 8% 28% 36% 19%	576
August	1st to 10th	Day	18% 3 10% 23% 27% 20%	526
	11th to 20th	Day	12% 2 7% 24% 30% 26%	519
	21st to end	Day	13% 2 10% 25% 28% 23%	583
September	1st to 10th	Day	9% 2 12% 28% 27% 21%	530
	11th to 20th	Day	17% 4 13% 28% 25% 13%	530
	21st to end	Day	22% 1 16% 28% 21% 12%	530
October	1st to 10th	Day	17% 4 21% 28% 22% 9%	530
	11th to 20th	Day	12% 6% 23% 29% 22% 8%	530
	21st to end	Day	13% 6% 24% 30% 21% 6%	583
November	1st to 10th	Day	16% 6% 27% 30% 16% 6%	535
	11th to 20th	Day	16% 9% 34% 27% 13% 1	540
	21st to end	Day	14% 12% 32% 26% 14% 2	398
December	1st to 10th	Day	21% 11% 37% 21% 10% 1	330
	11th to 20th	Day	19% 12% 32% 25% 8% 2	330
	21st to end	Day	20% 11% 39% 19% 9% 2	363
January	1st to 10th	Night	18% 13% 33% 29% 7%	840
	11th to 20th	Night	16% 13% 28% 33% 9%	840
	21st to end	Night	20% 11% 36% 29% 3	924
February	1st to 10th	Night	19% 9% 33% 33% 6%	801
	11th to 20th	Night	21% 13% 32% 29% 4	783
	21st to end	Night	17% 13% 32% 32% 5%	660
March	1st to 10th	Night	18% 10% 34% 31% 7%	800
	11th to 20th	Night	15% 9% 36% 33% 6% 1	800
	21st to end	Night	15% 10% 37% 30% 8%	880
April	1st to 10th	Night	13% 12% 32% 33% 9% 1	800
	11th to 20th	Night	13% 9% 30% 32% 15% 1	791
	21st to end	Night	9% 6% 31% 39% 14% 1	800
May	1st to 10th	Night	9% 6% 30% 37% 16% 1	708
	11th to 20th	Night	13% 5% 21% 39% 20% 2	591
	21st to end	Night	11% 2 11% 36% 35% 6%	650
June	1st to 10th	Night	11% 1 10% 43% 31% 4	600
	11th to 20th	Night	10% 1 8% 38% 35% 7%	600
	21st to end	Night	9% 8% 37% 38% 8%	600
July	1st to 10th	Night	10% 1 5% 35% 43% 6%	585
	11th to 20th	Night	8% 1 4 28% 50% 8%	582
	21st to end	Night	7% 1 5% 37% 44% 7%	657
August	1st to 10th	Night	15% 1 4 29% 42% 8%	597
	11th to 20th	Night	10% 1 4 32% 43% 10%	684
	21st to end	Night	13% 1 6% 31% 40% 9%	880
September	1st to 10th	Night	11% 2 8% 35% 40% 6%	800
	11th to 20th	Night	16% 1 10% 35% 32% 6%	800
	21st to end	Night	21% 1 11% 34% 30% 4	800
October	1st to 10th	Night	14% 3 18% 35% 25% 5%	800
	11th to 20th	Night	13% 4 22% 34% 24% 3	800
	21st to end	Night	12% 5% 22% 36% 22% 3	880
November	1st to 10th	Night	14% 5% 22% 38% 17% 3	820
	11th to 20th	Night	18% 8% 26% 33% 14% 1	840
	21st to end	Night	13% 8% 28% 35% 15% 2	840
December	1st to 10th	Night	20% 9% 25% 37% 10% 1	840
	11th to 20th	Night	17% 9% 26% 35% 12% 1	840
	21st to end	Night	19% 9% 28% 32% 11%	924

Page generated at 2026-01-29 01:21:44. Version ac07

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