Taxahaw
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Taxahaw clear sky chart from 2005-11-06 to 2026-08-15.

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 6% 5% 4 5% 4 6% 8% 42%	143530
	Night	13% 6% 2 6% 4 4 4 4 5% 7% 43%	138371
Transparency	Day	39% 6% 12% 19% 18% 6%	147163
	Night	39% 5% 11% 18% 20% 7%	142810
Seeing	Day	16% 9% 25% 25% 18% 7%	17769
	Night	16% 8% 25% 31% 18% 2	27810

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 6% 3 3 3 2 4 5% 53%	5258
	11th to 20th	Day	12% 5% 1 4 3 3 3 2 3 4 60%	5280
	21st to end	Day	18% 8% 2 7% 5% 4 4 3 4 5% 40%	5780
February	1st to 10th	Day	14% 7% 3 5% 4 4 3 3 4 7% 44%	1890
	11th to 20th	Day	20% 7% 2 6% 3 2 3 3 5% 5% 45%	1996
	21st to end	Day	19% 7% 2 7% 4 3 3 3 5% 5% 42%	1822
March	1st to 10th	Day	20% 7% 3 7% 4 4 3 3 4 5% 40%	5045
	11th to 20th	Day	9% 6% 2 5% 4 4 4 3 4 6% 54%	5090
	21st to end	Day	14% 6% 2 7% 4 4 3 3 4 5% 48%	5586
April	1st to 10th	Day	10% 4 2 5% 4 4 4 5% 6% 7% 50%	2326
	11th to 20th	Day	10% 6% 2 5% 3 4 4 4 5% 8% 49%	2494
	21st to end	Day	10% 5% 2 5% 4 4 5% 3 5% 7% 49%	2613
May	1st to 10th	Day	12% 6% 2 8% 5% 5% 5% 4 6% 9% 38%	7616
	11th to 20th	Day	14% 6% 2 6% 4 4 5% 4 7% 8% 39%	7626
	21st to end	Day	13% 7% 3 7% 6% 5% 5% 5% 7% 9% 35%	8391
June	1st to 10th	Day	9% 5% 2 7% 6% 5% 6% 5% 7% 10% 36%	2730
	11th to 20th	Day	8% 5% 2 5% 6% 6% 6% 5% 8% 10% 39%	2730
	21st to end	Day	6% 5% 2 6% 6% 6% 7% 6% 8% 12% 38%	2730
July	1st to 10th	Day	7% 5% 2 7% 6% 6% 7% 6% 9% 11% 34%	7680
	11th to 20th	Day	7% 6% 2 7% 6% 7% 8% 6% 10% 13% 29%	7680
	21st to end	Day	9% 7% 3 8% 6% 6% 7% 6% 9% 11% 28%	8340
August	1st to 10th	Day	23% 8% 3 7% 5% 6% 6% 6% 7% 9% 20%	4364
	11th to 20th	Day	10% 6% 2 7% 6% 5% 6% 6% 8% 11% 33%	4226
	21st to end	Day	6% 3 1 5% 4 4 5% 5% 7% 12% 48%	4317
September	1st to 10th	Day	7% 5% 2 6% 6% 6% 5% 5% 7% 9% 42%	2267
	11th to 20th	Day	12% 6% 2 7% 5% 5% 6% 4 7% 8% 39%	2200
	21st to end	Day	19% 6% 2 6% 4 3 4 4 5% 7% 40%	2200
October	1st to 10th	Day	14% 5% 2 4 3 4 5% 3 4 6% 49%	2054
	11th to 20th	Day	12% 4 2 5% 3 3 3 3 3 5% 58%	2000
	21st to end	Day	13% 3 2 6% 3 3 4 2 3 5% 57%	2200
November	1st to 10th	Day	12% 5% 2 4 3 3 3 2 5% 5% 55%	2057
	11th to 20th	Day	14% 5% 2 4 2 2 3 3 5% 6% 55%	2004
	21st to end	Day	13% 5% 2 5% 4 3 4 3 5% 6% 51%	1890
December	1st to 10th	Day	12% 7% 2 6% 5% 4 3 3 4 5% 50%	3020
	11th to 20th	Day	15% 6% 2 6% 4 4 4 3 5% 6% 45%	3463
	21st to end	Day	19% 6% 2 5% 3 3 3 3 4 6% 46%	4565
January	1st to 10th	Night	12% 6% 2 5% 3 3 3 3 4 5% 54%	7635
	11th to 20th	Night	11% 6% 2 5% 3 3 3 3 4 5% 54%	7680
	21st to end	Night	18% 9% 3 6% 4 3 3 2 4 5% 43%	8401
February	1st to 10th	Night	15% 6% 2 5% 4 3 4 3 5% 5% 47%	2730
	11th to 20th	Night	19% 7% 3 6% 4 4 3 3 4 5% 42%	2505
	21st to end	Night	16% 6% 2 4 4 3 4 4 4 6% 47%	1982
March	1st to 10th	Night	19% 8% 3 6% 4 4 3 3 4 5% 41%	5028
	11th to 20th	Night	11% 4 1 4 3 3 4 3 5% 7% 54%	5090
	21st to end	Night	15% 4 2 5% 4 4 4 3 5% 6% 49%	5588
April	1st to 10th	Night	11% 6% 2 4 4 4 4 4 6% 7% 49%	2294
	11th to 20th	Night	10% 5% 2 5% 4 3 3 3 5% 7% 53%	2075
	21st to end	Night	11% 4 2 5% 5% 4 4 4 6% 7% 49%	2023
May	1st to 10th	Night	12% 7% 3 7% 4 4 4 4 6% 10% 39%	5237
	11th to 20th	Night	15% 6% 2 6% 4 4 4 4 5% 9% 43%	5234
	21st to end	Night	15% 8% 3 8% 5% 5% 5% 4 7% 8% 33%	5761
June	1st to 10th	Night	10% 7% 3 7% 6% 7% 6% 4 6% 9% 35%	1890
	11th to 20th	Night	10% 7% 2 7% 5% 6% 6% 5% 8% 10% 35%	1890
	21st to end	Night	7% 5% 2 6% 6% 5% 5% 6% 8% 12% 38%	1890
July	1st to 10th	Night	8% 7% 3 8% 6% 5% 6% 6% 9% 13% 30%	5278
	11th to 20th	Night	10% 7% 3 8% 7% 6% 7% 6% 9% 13% 26%	5277
	21st to end	Night	12% 9% 3 10% 7% 6% 7% 5% 8% 10% 23%	5736
August	1st to 10th	Night	24% 7% 3 7% 6% 5% 6% 4 7% 9% 23%	3005
	11th to 20th	Night	11% 7% 2 8% 5% 6% 5% 5% 8% 9% 34%	2911
	21st to end	Night	6% 5% 1 5% 4 4 5% 4 7% 11% 49%	3548
September	1st to 10th	Night	9% 5% 2 6% 5% 4 4 4 7% 10% 43%	2129
	11th to 20th	Night	13% 7% 2 7% 4 4 4 3 6% 7% 42%	2200
	21st to end	Night	17% 7% 2 5% 4 5% 5% 4 5% 6% 41%	2200
October	1st to 10th	Night	13% 5% 2 5% 3 3 3 3 4 6% 51%	2345
	11th to 20th	Night	13% 4 2 5% 3 3 3 2 4 5% 55%	2400
	21st to end	Night	11% 5% 1 4 3 3 3 3 4 5% 57%	2640
November	1st to 10th	Night	13% 6% 2 5% 3 3 3 2 4 5% 53%	2461
	11th to 20th	Night	12% 6% 2 5% 4 3 3 3 4 5% 54%	2613
	21st to end	Night	13% 5% 2 4 3 4 4 3 6% 7% 49%	2730
December	1st to 10th	Night	13% 6% 2 5% 3 3 3 3 4 6% 52%	4380
	11th to 20th	Night	16% 8% 2 6% 4 3 3 3 4 6% 45%	4952
	21st to end	Night	19% 6% 2 5% 3 3 4 3 5% 5% 45%	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	36% 2 8% 21% 26% 6%	5259
	11th to 20th	Day	30% 3 4 13% 37% 14%	5280
	21st to end	Day	47% 2 4 17% 20% 10%	5780
February	1st to 10th	Day	41% 4 7% 23% 19% 6%	1890
	11th to 20th	Day	42% 4 6% 19% 23% 5%	2006
	21st to end	Day	44% 5% 7% 16% 20% 8%	1822
March	1st to 10th	Day	46% 4 6% 13% 20% 11%	5045
	11th to 20th	Day	32% 4 7% 13% 26% 18%	5090
	21st to end	Day	40% 4 7% 20% 23% 7%	5586
April	1st to 10th	Day	32% 5% 11% 21% 26% 6%	2326
	11th to 20th	Day	34% 5% 8% 22% 22% 9%	2494
	21st to end	Day	33% 6% 11% 23% 22% 4	2613
May	1st to 10th	Day	43% 6% 15% 23% 12% 2	7651
	11th to 20th	Day	42% 5% 14% 21% 16% 2	7630
	21st to end	Day	45% 7% 14% 16% 15% 3	8405
June	1st to 10th	Day	39% 9% 16% 23% 11% 2	2730
	11th to 20th	Day	36% 10% 18% 21% 13% 2	2730
	21st to end	Day	34% 11% 17% 23% 14% 1	2730
July	1st to 10th	Day	41% 7% 20% 26% 5% 1	7615
	11th to 20th	Day	44% 8% 28% 15% 4	7611
	21st to end	Day	47% 8% 17% 18% 9% 1	8156
August	1st to 10th	Day	57% 8% 18% 13% 4	4351
	11th to 20th	Day	42% 9% 17% 20% 11% 1	4265
	21st to end	Day	28% 8% 15% 31% 15% 2	4317
September	1st to 10th	Day	36% 9% 14% 19% 19% 3	2267
	11th to 20th	Day	41% 8% 11% 17% 20% 3	2200
	21st to end	Day	43% 6% 10% 20% 15% 6%	2200
October	1st to 10th	Day	33% 5% 6% 19% 27% 10%	3340
	11th to 20th	Day	20% 3 5% 18% 27% 28%	3240
	21st to end	Day	27% 3 4 23% 26% 17%	3538
November	1st to 10th	Day	31% 4 8% 18% 30% 10%	2057
	11th to 20th	Day	30% 4 8% 20% 27% 9%	2004
	21st to end	Day	34% 4 9% 21% 23% 9%	1890
December	1st to 10th	Day	38% 3 5% 17% 26% 10%	3020
	11th to 20th	Day	41% 3 10% 19% 21% 7%	3460
	21st to end	Day	40% 3 8% 24% 22% 2	4565
January	1st to 10th	Night	34% 3 9% 21% 28% 6%	7636
	11th to 20th	Night	33% 3 5% 14% 33% 11%	7680
	21st to end	Night	46% 2 3 15% 25% 9%	8401
February	1st to 10th	Night	40% 4 8% 19% 21% 7%	2730
	11th to 20th	Night	45% 4 7% 16% 23% 6%	2506
	21st to end	Night	38% 5% 9% 16% 22% 9%	1982
March	1st to 10th	Night	45% 5% 6% 12% 26% 7%	5028
	11th to 20th	Night	30% 4 7% 13% 28% 18%	5090
	21st to end	Night	37% 4 8% 21% 21% 9%	5588
April	1st to 10th	Night	33% 5% 10% 20% 23% 8%	2294
	11th to 20th	Night	31% 5% 9% 22% 23% 10%	2075
	21st to end	Night	33% 7% 11% 25% 20% 4	2023
May	1st to 10th	Night	41% 5% 15% 24% 13% 2	5264
	11th to 20th	Night	39% 6% 15% 24% 14% 1	5235
	21st to end	Night	46% 7% 13% 20% 12% 2	5771
June	1st to 10th	Night	44% 9% 14% 20% 12% 2	1890
	11th to 20th	Night	41% 9% 17% 20% 12% 1	1890
	21st to end	Night	35% 11% 18% 21% 12% 2	1890
July	1st to 10th	Night	43% 7% 24% 21% 5% 1	5235
	11th to 20th	Night	48% 12% 26% 10% 4 1	5226
	21st to end	Night	53% 8% 17% 14% 6% 2	5606
August	1st to 10th	Night	57% 7% 17% 15% 3 1	2994
	11th to 20th	Night	43% 9% 22% 19% 7% 1	2938
	21st to end	Night	29% 7% 13% 28% 19% 4	3548
September	1st to 10th	Night	35% 9% 15% 20% 15% 6%	2129
	11th to 20th	Night	41% 8% 13% 16% 20% 2	2200
	21st to end	Night	43% 7% 12% 18% 16% 5%	2200
October	1st to 10th	Night	34% 4 8% 21% 26% 6%	3839
	11th to 20th	Night	22% 3 4 17% 29% 25%	3899
	21st to end	Night	28% 3 5% 20% 26% 18%	4252
November	1st to 10th	Night	35% 4 7% 16% 26% 12%	2461
	11th to 20th	Night	33% 4 6% 17% 28% 12%	2613
	21st to end	Night	34% 4 7% 21% 26% 8%	2730
December	1st to 10th	Night	35% 4 7% 17% 28% 9%	4380
	11th to 20th	Night	42% 4 11% 16% 19% 9%	4954
	21st to end	Night	41% 3 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% 24% 42% 13% 2	330
	11th to 20th	Day	23% 22% 35% 16% 4	330
	21st to end	Day	22% 25% 35% 15% 2	363
February	1st to 10th	Day	18% 22% 39% 16% 5%	330
	11th to 20th	Day	38% 15% 38% 7% 2	330
	21st to end	Day	25% 19% 35% 17% 4	365
March	1st to 10th	Day	20% 18% 33% 22% 6%	540
	11th to 20th	Day	20% 18% 39% 18% 4 2	540
	21st to end	Day	19% 15% 37% 22% 7% 1	594
April	1st to 10th	Day	17% 17% 33% 23% 9% 1	540
	11th to 20th	Day	11% 16% 32% 24% 13% 3	532
	21st to end	Day	13% 10% 30% 28% 15% 3	540
May	1st to 10th	Day	12% 14% 35% 23% 13% 3	543
	11th to 20th	Day	16% 7% 24% 26% 21% 7%	567
	21st to end	Day	16% 6% 19% 25% 23% 11%	617
June	1st to 10th	Day	12% 2 21% 32% 25% 8%	570
	11th to 20th	Day	9% 4 18% 31% 26% 12%	570
	21st to end	Day	8% 2 15% 36% 31% 9%	570
July	1st to 10th	Day	9% 2 9% 23% 37% 20%	565
	11th to 20th	Day	10% 2 7% 27% 36% 17%	564
	21st to end	Day	9% 2 11% 31% 35% 12%	620
August	1st to 10th	Day	19% 3 13% 26% 23% 16%	566
	11th to 20th	Day	11% 2 11% 30% 28% 18%	535
	21st to end	Day	12% 2 13% 30% 27% 17%	583
September	1st to 10th	Day	9% 2 14% 34% 27% 14%	530
	11th to 20th	Day	14% 5% 14% 25% 32% 11%	530
	21st to end	Day	20% 5% 19% 28% 23% 5%	530
October	1st to 10th	Day	17% 5% 21% 29% 22% 8%	530
	11th to 20th	Day	13% 8% 25% 28% 20% 6%	530
	21st to end	Day	15% 9% 28% 25% 18% 5%	583
November	1st to 10th	Day	17% 8% 29% 29% 14% 4	535
	11th to 20th	Day	18% 14% 35% 23% 9% 2	444
	21st to end	Day	12% 15% 38% 23% 10% 2	330
December	1st to 10th	Day	25% 16% 37% 17% 4	330
	11th to 20th	Day	20% 13% 36% 22% 8% 2	330
	21st to end	Day	26% 12% 38% 17% 7% 1	363
January	1st to 10th	Night	19% 13% 35% 26% 6%	840
	11th to 20th	Night	18% 13% 35% 28% 6%	840
	21st to end	Night	20% 10% 38% 28% 3	924
February	1st to 10th	Night	19% 11% 36% 30% 4	840
	11th to 20th	Night	22% 14% 39% 22% 2	823
	21st to end	Night	20% 14% 36% 26% 4	692
March	1st to 10th	Night	18% 10% 35% 32% 5%	840
	11th to 20th	Night	17% 13% 36% 26% 8%	840
	21st to end	Night	18% 11% 37% 28% 6%	924
April	1st to 10th	Night	15% 15% 33% 29% 8%	840
	11th to 20th	Night	13% 12% 32% 30% 13%	831
	21st to end	Night	12% 7% 28% 41% 12%	763
May	1st to 10th	Night	13% 8% 32% 36% 12%	630
	11th to 20th	Night	14% 5% 25% 38% 17% 1	621
	21st to end	Night	15% 3 16% 33% 31% 2	683
June	1st to 10th	Night	13% 3 18% 40% 24% 3	630
	11th to 20th	Night	13% 3 16% 34% 27% 7%	630
	21st to end	Night	9% 2 14% 38% 32% 5%	630
July	1st to 10th	Night	8% 1 11% 35% 37% 7%	615
	11th to 20th	Night	10% 1 8% 30% 44% 6%	612
	21st to end	Night	9% 2 12% 34% 39% 4	690
August	1st to 10th	Night	16% 2 10% 27% 39% 6%	627
	11th to 20th	Night	14% 1 7% 33% 37% 7%	606
	21st to end	Night	12% 2 11% 30% 40% 5%	855
September	1st to 10th	Night	11% 2 12% 32% 37% 6%	800
	11th to 20th	Night	16% 2 15% 29% 35% 4	800
	21st to end	Night	21% 4 16% 31% 26% 3	800
October	1st to 10th	Night	15% 5% 19% 28% 28% 5%	800
	11th to 20th	Night	15% 6% 24% 32% 21% 2	800
	21st to end	Night	14% 7% 24% 31% 22% 2	880
November	1st to 10th	Night	17% 6% 24% 33% 16% 3	820
	11th to 20th	Night	15% 10% 30% 31% 12% 1	840
	21st to end	Night	15% 10% 30% 31% 13% 2	840
December	1st to 10th	Night	20% 10% 29% 33% 7% 1	840
	11th to 20th	Night	20% 8% 27% 36% 10%	840
	21st to end	Night	23% 13% 24% 30% 9%	924

Page generated at 2026-08-12 03:37:20. Version ac07

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