Charlotte, TX
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Charlotte, TX clear sky chart from 2005-11-06 to 2026-01-17.

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 5% 4 4 4 4 5% 7% 47%	127402
	Night	13% 5% 2 5% 3 3 3 3 5% 7% 51%	124599
Transparency	Day	36% 3 10% 23% 18% 11%	131220
	Night	33% 3 12% 22% 18% 12%	128844
Seeing	Day	13% 3 18% 31% 27% 9%	16207
	Night	14% 4 25% 39% 16% 1	26248

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% 6% 2 4 3 3 3 2 4 4 51%	4167
	11th to 20th	Day	17% 5% 1 4 3 3 3 2 4 5% 53%	4200
	21st to end	Day	25% 8% 2 5% 3 2 3 3 5% 6% 39%	4994
February	1st to 10th	Day	18% 8% 3 5% 4 2 3 3 4 5% 46%	2000
	11th to 20th	Day	18% 6% 3 6% 3 3 3 2 4 6% 45%	1949
	21st to end	Day	17% 6% 2 4 3 3 3 3 5% 5% 50%	1650
March	1st to 10th	Day	13% 6% 2 5% 3 3 4 3 5% 6% 51%	4823
	11th to 20th	Day	15% 7% 2 6% 4 3 3 3 3 4 52%	4980
	21st to end	Day	17% 8% 2 5% 3 3 3 2 4 6% 47%	5462
April	1st to 10th	Day	12% 6% 2 6% 4 4 3 4 5% 7% 47%	2200
	11th to 20th	Day	17% 5% 2 6% 4 3 4 2 5% 7% 45%	2203
	21st to end	Day	14% 8% 2 6% 4 3 4 3 4 5% 46%	2474
May	1st to 10th	Day	18% 7% 3 7% 5% 4 4 4 6% 7% 34%	5862
	11th to 20th	Day	8% 4 2 5% 4 4 4 4 7% 8% 51%	5862
	21st to end	Day	8% 6% 2 7% 4 5% 5% 5% 6% 9% 42%	6434
June	1st to 10th	Day	4 3 2 4 4 5% 5% 6% 8% 9% 51%	2600
	11th to 20th	Day	5% 3 2 5% 5% 5% 5% 5% 7% 10% 48%	2600
	21st to end	Day	7% 4 2 6% 6% 6% 6% 5% 8% 12% 38%	2600
July	1st to 10th	Day	11% 7% 3 8% 5% 4 5% 4 6% 8% 39%	5900
	11th to 20th	Day	5% 5% 3 6% 5% 5% 6% 5% 7% 10% 44%	5900
	21st to end	Day	5% 5% 2 7% 5% 5% 6% 5% 7% 10% 43%	6422
August	1st to 10th	Day	1 2 1 2 2 3 3 3 5% 8% 72%	3982
	11th to 20th	Day	3 2 1 3 3 3 4 5% 7% 11% 58%	3846
	21st to end	Day	4 3 1 5% 5% 5% 6% 5% 7% 12% 47%	4158
September	1st to 10th	Day	10% 5% 2 6% 5% 6% 6% 4 6% 8% 41%	2200
	11th to 20th	Day	10% 6% 2 6% 4 5% 6% 4 6% 9% 42%	2200
	21st to end	Day	8% 4 1 5% 4 5% 5% 5% 7% 8% 48%	2200
October	1st to 10th	Day	6% 4 2 5% 4 4 5% 3 5% 6% 58%	2200
	11th to 20th	Day	12% 4 2 4 4 4 3 3 5% 6% 53%	2128
	21st to end	Day	10% 3 1 4 3 3 3 2 4 5% 61%	2200
November	1st to 10th	Day	14% 7% 3 6% 3 4 3 3 4 7% 47%	2058
	11th to 20th	Day	13% 7% 2 4 3 3 3 3 5% 6% 52%	1960
	21st to end	Day	17% 7% 3 6% 4 4 4 2 4 5% 45%	1890
December	1st to 10th	Day	32% 11% 3 5% 3 2 3 1 3 4 34%	3030
	11th to 20th	Day	17% 8% 3 6% 4 4 4 3 5% 6% 42%	3481
	21st to end	Day	11% 5% 2 5% 3 3 3 3 4 4 56%	4587
January	1st to 10th	Night	19% 6% 2 4 2 2 3 2 4 6% 49%	6018
	11th to 20th	Night	14% 4 1 3 3 2 3 2 4 6% 59%	5955
	21st to end	Night	31% 5% 2 5% 2 2 3 2 4 6% 38%	5984
February	1st to 10th	Night	16% 6% 2 4 4 3 4 3 4 6% 50%	2400
	11th to 20th	Night	20% 6% 2 4 3 3 2 2 4 5% 49%	2338
	21st to end	Night	16% 6% 2 4 4 3 3 3 4 5% 48%	1980
March	1st to 10th	Night	16% 7% 2 5% 3 3 3 3 4 5% 48%	5035
	11th to 20th	Night	15% 7% 2 5% 3 2 3 2 3 5% 54%	4980
	21st to end	Night	17% 6% 2 4 3 3 3 3 5% 6% 49%	5467
April	1st to 10th	Night	10% 6% 2 5% 4 4 3 5% 6% 8% 48%	2200
	11th to 20th	Night	15% 6% 2 5% 4 3 3 3 5% 6% 48%	2142
	21st to end	Night	15% 7% 2 6% 4 4 3 3 5% 6% 45%	1925
May	1st to 10th	Night	19% 8% 3 6% 4 3 4 2 5% 7% 38%	4053
	11th to 20th	Night	9% 4 2 5% 3 4 4 3 6% 9% 51%	4053
	21st to end	Night	9% 7% 3 7% 5% 4 5% 4 6% 11% 40%	4443
June	1st to 10th	Night	5% 2 1 3 3 3 4 3 6% 9% 62%	1800
	11th to 20th	Night	3 2 1 4 3 3 4 3 6% 9% 62%	1800
	21st to end	Night	6% 4 2 5% 4 3 4 5% 7% 10% 52%	1800
July	1st to 10th	Night	8% 6% 2 7% 4 5% 5% 4 7% 10% 42%	4078
	11th to 20th	Night	4 4 2 5% 3 3 5% 4 6% 11% 52%	4077
	21st to end	Night	5% 4 2 5% 4 4 4 4 7% 9% 51%	4449
August	1st to 10th	Night	1 1 2 2 2 3 2 4 6% 78%	3172
	11th to 20th	Night	2 2 1 3 2 3 4 4 6% 12% 60%	3213
	21st to end	Night	4 3 1 4 3 3 4 4 7% 11% 56%	3743
September	1st to 10th	Night	7% 6% 2 6% 5% 3 6% 4 7% 9% 45%	2200
	11th to 20th	Night	9% 6% 2 5% 4 4 4 4 5% 9% 48%	2200
	21st to end	Night	6% 4 1 5% 3 3 4 4 6% 10% 54%	2200
October	1st to 10th	Night	5% 4 1 3 4 2 4 3 5% 7% 64%	2200
	11th to 20th	Night	11% 4 1 4 3 2 3 3 4 6% 60%	2250
	21st to end	Night	12% 4 1 3 2 2 2 2 3 5% 64%	2640
November	1st to 10th	Night	14% 4 2 4 3 3 3 2 4 5% 55%	2460
	11th to 20th	Night	11% 5% 2 4 3 3 3 3 5% 6% 57%	2655
	21st to end	Night	17% 5% 2 4 4 4 3 3 4 5% 49%	2730
December	1st to 10th	Night	31% 9% 3 5% 3 2 2 2 3 4 35%	4380
	11th to 20th	Night	17% 7% 2 6% 3 3 3 2 4 5% 47%	4946
	21st to end	Night	13% 5% 2 4 2 2 3 2 4 6% 56%	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	38% 2 4 19% 24% 13%	4168
	11th to 20th	Day	36% 2 3 19% 21% 20%	4200
	21st to end	Day	47% 2 4 13% 22% 12%	4994
February	1st to 10th	Day	43% 2 5% 13% 20% 17%	2000
	11th to 20th	Day	42% 2 6% 18% 19% 13%	1959
	21st to end	Day	38% 2 8% 18% 19% 15%	1650
March	1st to 10th	Day	36% 2 7% 20% 15% 22%	4823
	11th to 20th	Day	38% 2 4 9% 17% 30%	4980
	21st to end	Day	39% 2 7% 22% 17% 12%	5464
April	1st to 10th	Day	37% 3 9% 18% 18% 14%	2200
	11th to 20th	Day	41% 2 7% 19% 17% 14%	2203
	21st to end	Day	41% 3 6% 20% 18% 12%	2474
May	1st to 10th	Day	48% 4 10% 21% 12% 5%	5900
	11th to 20th	Day	32% 3 11% 26% 19% 10%	5866
	21st to end	Day	37% 4 9% 34% 15% 1	6447
June	1st to 10th	Day	26% 5% 14% 31% 20% 4	2600
	11th to 20th	Day	29% 4 12% 27% 23% 5%	2600
	21st to end	Day	38% 6% 14% 27% 13% 3	2600
July	1st to 10th	Day	43% 4 17% 30% 6%	5836
	11th to 20th	Day	34% 5% 19% 30% 11% 1	5831
	21st to end	Day	34% 4 18% 28% 14% 2	6240
August	1st to 10th	Day	12% 3 12% 48% 23% 2	3968
	11th to 20th	Day	19% 4 25% 39% 11% 2	3882
	21st to end	Day	29% 6% 20% 25% 18% 1	4157
September	1st to 10th	Day	41% 5% 13% 20% 15% 7%	2200
	11th to 20th	Day	38% 5% 13% 23% 17% 4	2200
	21st to end	Day	32% 5% 11% 24% 17% 12%	2200
October	1st to 10th	Day	18% 3 5% 14% 24% 36%	3590
	11th to 20th	Day	25% 3 9% 20% 21% 22%	3446
	21st to end	Day	25% 3 5% 20% 30% 18%	3538
November	1st to 10th	Day	39% 3 6% 19% 19% 14%	2058
	11th to 20th	Day	35% 2 8% 18% 21% 16%	1960
	21st to end	Day	44% 2 5% 17% 19% 12%	1890
December	1st to 10th	Day	57% 1 4 13% 15% 9%	3030
	11th to 20th	Day	44% 2 8% 16% 17% 14%	3479
	21st to end	Day	33% 2 4 21% 26% 15%	4587
January	1st to 10th	Night	38% 2 5% 17% 20% 18%	6018
	11th to 20th	Night	29% 1 4 19% 25% 21%	5955
	21st to end	Night	50% 2 3 12% 20% 13%	5984
February	1st to 10th	Night	37% 2 8% 14% 18% 21%	2400
	11th to 20th	Night	40% 2 6% 18% 19% 16%	2338
	21st to end	Night	39% 2 6% 18% 18% 16%	1980
March	1st to 10th	Night	40% 2 8% 18% 15% 17%	5035
	11th to 20th	Night	37% 1 7% 13% 15% 26%	4980
	21st to end	Night	37% 2 12% 19% 19% 11%	5467
April	1st to 10th	Night	34% 3 12% 21% 16% 14%	2200
	11th to 20th	Night	38% 2 10% 18% 15% 17%	2142
	21st to end	Night	40% 3 10% 18% 17% 11%	1925
May	1st to 10th	Night	47% 3 9% 19% 16% 6%	4080
	11th to 20th	Night	31% 3 13% 21% 21% 11%	4054
	21st to end	Night	39% 3 16% 31% 10% 1	4452
June	1st to 10th	Night	20% 3 19% 34% 22% 2	1800
	11th to 20th	Night	20% 4 12% 34% 25% 5%	1800
	21st to end	Night	27% 6% 22% 29% 14% 2	1800
July	1st to 10th	Night	38% 6% 24% 26% 4	4035
	11th to 20th	Night	27% 5% 26% 31% 11%	4026
	21st to end	Night	29% 5% 24% 28% 13% 1	4320
August	1st to 10th	Night	9% 3 15% 52% 21%	3162
	11th to 20th	Night	19% 4 34% 36% 7% 1	3243
	21st to end	Night	22% 9% 26% 29% 13% 1	3743
September	1st to 10th	Night	35% 6% 19% 20% 14% 7%	2200
	11th to 20th	Night	34% 5% 14% 26% 17% 4	2200
	21st to end	Night	26% 4 15% 26% 18% 11%	2200
October	1st to 10th	Night	15% 3 7% 18% 21% 35%	3590
	11th to 20th	Night	20% 3 10% 19% 26% 22%	3658
	21st to end	Night	21% 2 9% 20% 31% 17%	4252
November	1st to 10th	Night	32% 2 8% 20% 22% 15%	2460
	11th to 20th	Night	29% 3 11% 19% 20% 17%	2655
	21st to end	Night	39% 2 8% 19% 19% 13%	2730
December	1st to 10th	Night	57% 1 5% 13% 12% 11%	4380
	11th to 20th	Night	41% 2 7% 15% 18% 17%	4947
	21st to end	Night	31% 2 6% 17% 25% 18%	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	22% 5% 31% 29% 12% 2	330
	11th to 20th	Day	20% 7% 30% 29% 13% 1	318
	21st to end	Day	20% 5% 37% 26% 11% 1	330
February	1st to 10th	Day	21% 6% 26% 27% 17% 2	300
	11th to 20th	Day	23% 7% 35% 26% 8% 1	300
	21st to end	Day	22% 6% 39% 25% 7%	249
March	1st to 10th	Day	20% 9% 37% 24% 9% 1	300
	11th to 20th	Day	16% 6% 41% 25% 12%	300
	21st to end	Day	18% 6% 38% 29% 8%	330
April	1st to 10th	Day	17% 5% 37% 29% 11%	300
	11th to 20th	Day	21% 6% 32% 28% 13%	321
	21st to end	Day	16% 7% 37% 32% 7% 1	574
May	1st to 10th	Day	16% 5% 33% 36% 9%	703
	11th to 20th	Day	15% 4 28% 37% 13% 3	725
	21st to end	Day	13% 3 23% 39% 21% 2	789
June	1st to 10th	Day	6% 1 12% 40% 34% 7%	730
	11th to 20th	Day	5% 2 10% 45% 32% 6%	730
	21st to end	Day	8% 2 8% 32% 38% 13%	730
July	1st to 10th	Day	12% 2 4 31% 37% 14%	721
	11th to 20th	Day	5% 1 5% 29% 47% 14%	718
	21st to end	Day	5% 2 3 28% 47% 15%	794
August	1st to 10th	Day	3 1 3 29% 43% 21%	578
	11th to 20th	Day	5% 3 30% 41% 21%	517
	21st to end	Day	6% 1 2 21% 37% 33%	494
September	1st to 10th	Day	10% 3 21% 44% 23%	330
	11th to 20th	Day	8% 1 3 16% 46% 27%	330
	21st to end	Day	8% 1 3 21% 44% 23%	330
October	1st to 10th	Day	7% 1 6% 26% 42% 17%	330
	11th to 20th	Day	11% 7% 37% 32% 13%	330
	21st to end	Day	13% 6% 20% 29% 25% 8%	363
November	1st to 10th	Day	15% 2 19% 30% 27% 6%	330
	11th to 20th	Day	18% 3 18% 28% 27% 5%	330
	21st to end	Day	22% 7% 29% 24% 14% 3	330
December	1st to 10th	Day	25% 2 22% 31% 17% 4	330
	11th to 20th	Day	24% 6% 22% 26% 20% 1	330
	21st to end	Day	16% 6% 23% 34% 18% 3	363
January	1st to 10th	Night	20% 5% 25% 38% 12%	1050
	11th to 20th	Night	21% 5% 26% 39% 8%	1020
	21st to end	Night	24% 5% 26% 36% 9%	880
February	1st to 10th	Night	19% 8% 30% 36% 7%	800
	11th to 20th	Night	24% 6% 32% 31% 6%	784
	21st to end	Night	21% 10% 36% 31% 2	660
March	1st to 10th	Night	22% 8% 39% 27% 4	655
	11th to 20th	Night	18% 7% 38% 33% 4	600
	21st to end	Night	17% 7% 46% 26% 4	660
April	1st to 10th	Night	13% 7% 48% 28% 4	600
	11th to 20th	Night	17% 7% 45% 27% 3	593
	21st to end	Night	18% 7% 45% 25% 5%	600
May	1st to 10th	Night	13% 6% 48% 28% 5%	600
	11th to 20th	Night	14% 5% 40% 35% 6% 1	591
	21st to end	Night	9% 4 41% 39% 7%	650
June	1st to 10th	Night	5% 27% 50% 17% 1	600
	11th to 20th	Night	4 1 31% 51% 13%	600
	21st to end	Night	7% 2 16% 49% 23% 2	600
July	1st to 10th	Night	8% 2 12% 53% 23% 3	585
	11th to 20th	Night	3 1 11% 54% 29% 1	582
	21st to end	Night	5% 1 11% 53% 30% 1	657
August	1st to 10th	Night	2 1 12% 53% 30% 2	597
	11th to 20th	Night	5% 9% 52% 31% 3	594
	21st to end	Night	6% 1 7% 41% 41% 4	660
September	1st to 10th	Night	9% 2 6% 45% 35% 4	600
	11th to 20th	Night	11% 1 5% 39% 41% 3	600
	21st to end	Night	8% 1 10% 42% 36% 4	600
October	1st to 10th	Night	6% 1 10% 46% 35% 3	600
	11th to 20th	Night	11% 2 18% 47% 21% 1	650
	21st to end	Night	12% 4 24% 37% 21% 2	880
November	1st to 10th	Night	14% 3 19% 39% 23% 2	820
	11th to 20th	Night	12% 2 22% 43% 20% 2	975
	21st to end	Night	19% 5% 23% 37% 15% 1	1050
December	1st to 10th	Night	23% 3 21% 37% 15% 1	1050
	11th to 20th	Night	24% 4 22% 37% 13%	1050
	21st to end	Night	18% 5% 22% 42% 12%	1155

Page generated at 2026-01-14 00:14:30. Version ac07

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