Gaston County
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gaston County clear sky chart from 2005-11-06 to 2025-12-03.

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 4 4 6% 8% 44%	127048
	Night	14% 6% 2 6% 4 4 4 4 5% 7% 44%	123654
Transparency	Day	25% 38% 8% 14% 12% 4	130707
	Night	25% 38% 6% 12% 14% 5%	128064
Seeing	Day	16% 8% 22% 24% 20% 10%	16697
	Night	16% 7% 24% 31% 20% 3	26759

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	14% 6% 1 4 3 2 2 2 3 5% 56%	4056
	11th to 20th	Day	12% 6% 2 4 3 3 3 2 3 3 59%	4060
	21st to end	Day	18% 6% 2 5% 4 4 4 3 4 5% 45%	4466
February	1st to 10th	Day	15% 7% 2 4 4 4 4 4 7% 7% 43%	1800
	11th to 20th	Day	22% 6% 2 4 3 3 2 3 4 5% 45%	1940
	21st to end	Day	18% 8% 3 6% 4 4 4 3 4 6% 42%	1685
March	1st to 10th	Day	20% 7% 2 6% 3 3 3 3 4 6% 41%	4935
	11th to 20th	Day	9% 5% 2 6% 3 3 3 2 4 7% 55%	4980
	21st to end	Day	17% 7% 2 6% 4 3 3 3 4 5% 47%	5465
April	1st to 10th	Day	11% 5% 1 5% 3 4 4 4 6% 8% 50%	2200
	11th to 20th	Day	12% 5% 2 5% 4 3 4 4 5% 7% 49%	2354
	21st to end	Day	13% 5% 2 6% 4 4 4 4 5% 7% 47%	2576
May	1st to 10th	Day	10% 6% 2 7% 5% 5% 6% 5% 8% 10% 36%	5862
	11th to 20th	Day	19% 7% 3 7% 5% 5% 5% 4 6% 9% 31%	5861
	21st to end	Day	12% 5% 2 6% 4 4 5% 4 6% 9% 43%	6433
June	1st to 10th	Day	9% 6% 3 6% 4 5% 5% 5% 8% 11% 38%	2600
	11th to 20th	Day	7% 5% 2 6% 5% 5% 5% 5% 8% 10% 43%	2600
	21st to end	Day	6% 5% 2 6% 5% 5% 5% 5% 9% 12% 40%	2600
July	1st to 10th	Day	9% 5% 2 7% 5% 5% 6% 5% 8% 10% 38%	5900
	11th to 20th	Day	6% 5% 2 6% 5% 6% 7% 5% 8% 14% 35%	5900
	21st to end	Day	9% 6% 3 8% 6% 6% 6% 5% 8% 11% 31%	6424
August	1st to 10th	Day	20% 6% 2 6% 5% 6% 5% 5% 8% 10% 26%	4234
	11th to 20th	Day	10% 5% 2 6% 5% 6% 6% 4 8% 11% 37%	4174
	21st to end	Day	6% 4 1 5% 3 4 5% 4 6% 9% 53%	4397
September	1st to 10th	Day	8% 5% 2 5% 4 5% 6% 5% 7% 9% 44%	2201
	11th to 20th	Day	13% 6% 2 6% 4 4 4 5% 6% 8% 42%	2200
	21st to end	Day	18% 6% 2 6% 5% 4 4 4 5% 6% 40%	2200
October	1st to 10th	Day	14% 5% 2 3 3 3 3 2 4 5% 55%	2090
	11th to 20th	Day	13% 5% 1 4 3 3 3 2 3 6% 59%	2000
	21st to end	Day	14% 5% 2 4 3 3 2 2 4 4 58%	2200
November	1st to 10th	Day	13% 6% 2 5% 3 2 3 2 4 5% 54%	2057
	11th to 20th	Day	13% 5% 2 3 3 3 3 3 5% 6% 55%	1921
	21st to end	Day	14% 5% 2 5% 4 3 4 3 5% 5% 50%	1890
December	1st to 10th	Day	14% 5% 2 4 3 3 3 2 4 5% 54%	2948
	11th to 20th	Day	19% 7% 3 6% 4 4 4 3 5% 6% 41%	3373
	21st to end	Day	21% 6% 2 4 3 3 3 3 4 6% 45%	4466
January	1st to 10th	Night	13% 5% 2 4 3 3 3 2 3 4 58%	5889
	11th to 20th	Night	12% 6% 2 4 3 3 3 3 3 5% 56%	5900
	21st to end	Night	18% 7% 2 4 3 3 3 3 4 6% 48%	6490
February	1st to 10th	Night	15% 6% 2 5% 4 4 4 3 5% 6% 46%	2600
	11th to 20th	Night	21% 7% 2 5% 4 3 3 3 4 4 43%	2343
	21st to end	Night	15% 6% 2 5% 4 3 4 4 5% 7% 45%	1944
March	1st to 10th	Night	19% 6% 2 6% 4 3 3 3 4 5% 45%	4918
	11th to 20th	Night	9% 4 2 4 3 3 4 3 5% 7% 55%	4980
	21st to end	Night	16% 4 2 5% 4 4 4 3 5% 6% 48%	5467
April	1st to 10th	Night	12% 5% 2 5% 4 4 4 3 6% 7% 48%	2200
	11th to 20th	Night	12% 5% 2 6% 3 4 3 3 5% 7% 52%	1995
	21st to end	Night	12% 5% 2 5% 5% 5% 4 4 5% 7% 47%	1840
May	1st to 10th	Night	13% 7% 3 7% 5% 4 4 4 6% 9% 39%	4033
	11th to 20th	Night	19% 7% 2 7% 5% 5% 5% 3 6% 9% 32%	4032
	21st to end	Night	14% 5% 2 6% 4 4 5% 4 7% 9% 40%	4421
June	1st to 10th	Night	10% 6% 2 7% 5% 6% 6% 5% 8% 10% 35%	1800
	11th to 20th	Night	9% 6% 2 7% 6% 6% 5% 6% 7% 10% 37%	1800
	21st to end	Night	6% 5% 2 6% 6% 6% 6% 5% 9% 12% 37%	1800
July	1st to 10th	Night	10% 7% 3 9% 6% 6% 7% 5% 7% 10% 30%	4058
	11th to 20th	Night	8% 7% 3 7% 6% 5% 6% 6% 11% 13% 29%	4057
	21st to end	Night	11% 8% 4 9% 7% 6% 7% 6% 8% 10% 24%	4427
August	1st to 10th	Night	21% 10% 3 7% 5% 4 5% 4 7% 8% 24%	2915
	11th to 20th	Night	11% 8% 3 8% 6% 6% 7% 5% 8% 9% 31%	2875
	21st to end	Night	5% 4 2 6% 5% 5% 5% 5% 7% 9% 47%	3454
September	1st to 10th	Night	9% 6% 2 6% 4 4 5% 4 7% 9% 43%	2194
	11th to 20th	Night	15% 7% 3 7% 5% 4 5% 5% 5% 7% 38%	2200
	21st to end	Night	17% 7% 2 7% 4 4 4 4 5% 6% 40%	2200
October	1st to 10th	Night	14% 5% 1 5% 3 4 4 3 4 6% 50%	2309
	11th to 20th	Night	14% 5% 2 4 3 3 3 3 4 5% 54%	2400
	21st to end	Night	13% 4 2 5% 2 3 3 3 3 5% 58%	2640
November	1st to 10th	Night	14% 5% 2 5% 4 3 3 2 4 5% 53%	2461
	11th to 20th	Night	12% 4 2 5% 4 3 3 3 5% 5% 53%	2693
	21st to end	Night	13% 4 2 4 4 4 5% 3 5% 7% 50%	2730
December	1st to 10th	Night	16% 6% 2 4 3 3 3 2 4 5% 52%	4277
	11th to 20th	Night	20% 7% 2 5% 4 3 3 3 4 5% 43%	4822
	21st to end	Night	20% 4 2 4 3 3 3 3 4 6% 46%	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	24% 25% 3 14% 27% 7%	4057
	11th to 20th	Day	22% 25% 2 11% 31% 9%	4060
	21st to end	Day	33% 28% 2 12% 18% 8%	4466
February	1st to 10th	Day	15% 62% 3 11% 8% 2	1800
	11th to 20th	Day	19% 61% 3 7% 8% 2	1950
	21st to end	Day	18% 62% 3 4 11% 3	1685
March	1st to 10th	Day	38% 28% 4 8% 11% 11%	4935
	11th to 20th	Day	20% 29% 3 10% 22% 17%	4980
	21st to end	Day	29% 28% 3 18% 17% 5%	5465
April	1st to 10th	Day	15% 62% 4 8% 9% 2	2200
	11th to 20th	Day	16% 62% 3 9% 7% 2	2354
	21st to end	Day	14% 62% 5% 12% 7% 1	2576
May	1st to 10th	Day	31% 31% 15% 16% 7% 1	5897
	11th to 20th	Day	39% 29% 10% 15% 7%	5865
	21st to end	Day	28% 30% 9% 15% 14% 3	6447
June	1st to 10th	Day	15% 63% 6% 10% 5% 1	2600
	11th to 20th	Day	11% 63% 10% 9% 7%	2600
	21st to end	Day	14% 62% 8% 11% 6%	2600
July	1st to 10th	Day	30% 28% 14% 21% 7%	5835
	11th to 20th	Day	29% 29% 28% 14% 1	5831
	21st to end	Day	37% 28% 11% 19% 5% 1	6240
August	1st to 10th	Day	38% 36% 12% 12% 2	4221
	11th to 20th	Day	24% 37% 15% 15% 8% 1	4213
	21st to end	Day	13% 36% 10% 28% 12% 1	4397
September	1st to 10th	Day	14% 59% 6% 11% 9% 1	2201
	11th to 20th	Day	17% 58% 6% 10% 9% 1	2200
	21st to end	Day	23% 57% 7% 8% 5% 1	2200
October	1st to 10th	Day	20% 35% 3 15% 19% 8%	3402
	11th to 20th	Day	10% 35% 2 12% 21% 21%	3240
	21st to end	Day	16% 34% 2 19% 16% 13%	3538
November	1st to 10th	Day	20% 53% 3 9% 11% 4	2057
	11th to 20th	Day	15% 54% 3 13% 13% 3	1921
	21st to end	Day	16% 54% 4 12% 12% 2	1890
December	1st to 10th	Day	22% 34% 3 13% 21% 8%	2948
	11th to 20th	Day	34% 31% 4 11% 15% 5%	3370
	21st to end	Day	31% 26% 5% 23% 13% 1	4466
January	1st to 10th	Night	22% 25% 2 12% 30% 8%	5889
	11th to 20th	Night	24% 26% 2 11% 30% 7%	5900
	21st to end	Night	30% 27% 2 13% 20% 7%	6490
February	1st to 10th	Night	16% 61% 4 9% 8% 2	2600
	11th to 20th	Night	20% 60% 3 6% 8% 2	2344
	21st to end	Night	14% 61% 3 8% 10% 4	1944
March	1st to 10th	Night	33% 29% 4 7% 20% 6%	4918
	11th to 20th	Night	18% 28% 3 10% 24% 17%	4980
	21st to end	Night	27% 29% 3 18% 17% 7%	5467
April	1st to 10th	Night	15% 62% 4 9% 8% 3	2200
	11th to 20th	Night	14% 62% 4 9% 6% 3	1995
	21st to end	Night	14% 62% 5% 11% 7% 1	1840
May	1st to 10th	Night	32% 30% 11% 16% 10% 1	4060
	11th to 20th	Night	36% 30% 11% 14% 8%	4033
	21st to end	Night	28% 31% 9% 18% 12% 2	4429
June	1st to 10th	Night	16% 63% 7% 9% 4 1	1800
	11th to 20th	Night	14% 63% 8% 10% 5%	1800
	21st to end	Night	14% 63% 8% 9% 6% 1	1800
July	1st to 10th	Night	37% 28% 14% 14% 6%	4015
	11th to 20th	Night	35% 32% 21% 11% 1	4006
	21st to end	Night	44% 27% 11% 14% 3	4297
August	1st to 10th	Night	43% 36% 11% 9% 1	2904
	11th to 20th	Night	30% 37% 16% 10% 6%	2902
	21st to end	Night	16% 36% 7% 21% 18% 2	3454
September	1st to 10th	Night	14% 59% 8% 9% 9% 1	2194
	11th to 20th	Night	21% 58% 6% 7% 8% 1	2200
	21st to end	Night	23% 58% 7% 8% 4 1	2200
October	1st to 10th	Night	26% 35% 5% 12% 17% 5%	3777
	11th to 20th	Night	11% 35% 3 13% 19% 19%	3899
	21st to end	Night	18% 34% 2 15% 19% 13%	4252
November	1st to 10th	Night	20% 52% 3 9% 11% 4	2461
	11th to 20th	Night	16% 54% 3 9% 13% 6%	2693
	21st to end	Night	16% 54% 3 12% 13% 3	2730
December	1st to 10th	Night	24% 34% 3 13% 20% 6%	4277
	11th to 20th	Night	33% 32% 6% 10% 13% 7%	4824
	21st to end	Night	30% 27% 8% 18% 17% 1	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	20% 18% 36% 22% 4	300
	11th to 20th	Day	23% 20% 32% 20% 6%	300
	21st to end	Day	22% 18% 37% 16% 7%	330
February	1st to 10th	Day	19% 18% 35% 20% 7% 1	300
	11th to 20th	Day	35% 16% 34% 12% 3	300
	21st to end	Day	26% 20% 32% 18% 4	284
March	1st to 10th	Day	22% 15% 29% 24% 8% 1	500
	11th to 20th	Day	19% 13% 39% 21% 7%	500
	21st to end	Day	21% 14% 35% 23% 6% 1	550
April	1st to 10th	Day	20% 14% 32% 20% 12% 1	500
	11th to 20th	Day	14% 14% 29% 25% 14% 4	492
	21st to end	Day	17% 8% 27% 26% 17% 5%	500
May	1st to 10th	Day	10% 11% 34% 24% 16% 4	503
	11th to 20th	Day	17% 5% 20% 27% 22% 9%	527
	21st to end	Day	15% 5% 15% 23% 27% 14%	573
June	1st to 10th	Day	13% 2 15% 32% 27% 11%	530
	11th to 20th	Day	10% 3 14% 28% 26% 19%	530
	21st to end	Day	8% 2 11% 29% 33% 17%	530
July	1st to 10th	Day	10% 2 8% 21% 32% 28%	525
	11th to 20th	Day	7% 2 6% 24% 36% 24%	524
	21st to end	Day	7% 2 7% 27% 38% 20%	576
August	1st to 10th	Day	17% 2 11% 25% 28% 17%	526
	11th to 20th	Day	13% 3 8% 26% 30% 21%	519
	21st to end	Day	11% 3 10% 22% 29% 25%	583
September	1st to 10th	Day	11% 2 12% 26% 30% 21%	530
	11th to 20th	Day	16% 3 11% 21% 30% 18%	530
	21st to end	Day	22% 4 20% 23% 25% 8%	530
October	1st to 10th	Day	16% 4 19% 28% 23% 11%	530
	11th to 20th	Day	13% 6% 23% 28% 23% 7%	530
	21st to end	Day	19% 5% 22% 28% 19% 6%	583
November	1st to 10th	Day	21% 7% 23% 30% 16% 4	535
	11th to 20th	Day	15% 11% 33% 29% 9% 2	361
	21st to end	Day	10% 13% 36% 26% 13% 2	330
December	1st to 10th	Day	24% 10% 37% 22% 7% 1	306
	11th to 20th	Day	22% 11% 31% 26% 9% 1	300
	21st to end	Day	27% 13% 31% 20% 8% 1	330
January	1st to 10th	Night	20% 13% 33% 28% 6%	800
	11th to 20th	Night	20% 11% 35% 29% 5%	800
	21st to end	Night	18% 9% 40% 30% 3	880
February	1st to 10th	Night	18% 9% 35% 34% 4	800
	11th to 20th	Night	24% 11% 40% 23% 2	783
	21st to end	Night	20% 13% 38% 26% 3	660
March	1st to 10th	Night	17% 12% 31% 35% 5%	800
	11th to 20th	Night	16% 11% 36% 29% 8% 1	800
	21st to end	Night	20% 9% 36% 28% 7%	880
April	1st to 10th	Night	17% 12% 33% 31% 8%	800
	11th to 20th	Night	13% 13% 30% 29% 15%	791
	21st to end	Night	13% 6% 27% 36% 17%	640
May	1st to 10th	Night	12% 7% 28% 35% 18%	600
	11th to 20th	Night	14% 5% 21% 36% 22% 2	591
	21st to end	Night	16% 3 13% 31% 33% 3	650
June	1st to 10th	Night	12% 3 13% 40% 30% 3	600
	11th to 20th	Night	12% 3 14% 30% 32% 10%	600
	21st to end	Night	8% 2 10% 36% 39% 6%	600
July	1st to 10th	Night	9% 3 8% 28% 43% 9%	585
	11th to 20th	Night	8% 2 6% 28% 46% 10%	582
	21st to end	Night	7% 2 9% 32% 43% 7%	657
August	1st to 10th	Night	16% 2 6% 29% 39% 8%	597
	11th to 20th	Night	14% 2 9% 27% 40% 9%	594
	21st to end	Night	11% 2 9% 25% 46% 7%	800
September	1st to 10th	Night	11% 2 9% 31% 41% 6%	800
	11th to 20th	Night	17% 3 12% 24% 37% 7%	800
	21st to end	Night	20% 3 15% 33% 28% 2	800
October	1st to 10th	Night	16% 4 17% 30% 28% 6%	800
	11th to 20th	Night	16% 5% 23% 33% 20% 2	800
	21st to end	Night	15% 6% 23% 33% 21% 3	880
November	1st to 10th	Night	15% 5% 23% 36% 18% 2	820
	11th to 20th	Night	13% 9% 30% 36% 11% 1	840
	21st to end	Night	14% 7% 30% 36% 13% 1	840
December	1st to 10th	Night	23% 9% 27% 33% 7%	809
	11th to 20th	Night	20% 7% 28% 35% 9% 1	800
	21st to end	Night	24% 8% 27% 32% 9%	880

Page generated at 2025-11-30 01:00:50. Version ac07

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