Mt. Pisgah Parking Lot
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mt. Pisgah Parking Lot 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	10% 7% 3 7% 5% 5% 6% 4 6% 8% 39%	126905
	Night	10% 7% 2 6% 5% 5% 5% 4 6% 8% 43%	123809
Transparency	Day	41% 7% 12% 18% 16% 6%	130616
	Night	36% 8% 13% 19% 18% 7%	128154
Seeing	Day	19% 16% 24% 21% 13% 6%	16462
	Night	17% 14% 22% 26% 17% 3	26507

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	7% 6% 2 5% 3 3 3 3 5% 6% 56%	4056
	11th to 20th	Day	6% 6% 2 5% 3 3 4 3 5% 4 59%	4060
	21st to end	Day	11% 7% 2 6% 4 4 5% 4 5% 6% 46%	4466
February	1st to 10th	Day	9% 9% 2 7% 4 5% 4 5% 5% 7% 44%	1905
	11th to 20th	Day	11% 8% 3 8% 4 5% 4 4 5% 6% 43%	1948
	21st to end	Day	10% 7% 2 7% 5% 6% 5% 5% 6% 6% 42%	1650
March	1st to 10th	Day	14% 6% 2 6% 4 4 5% 4 6% 6% 42%	4800
	11th to 20th	Day	8% 7% 3 6% 4 3 4 3 4 6% 52%	4980
	21st to end	Day	13% 9% 2 7% 5% 4 4 3 4 5% 44%	5465
April	1st to 10th	Day	9% 7% 2 6% 4 4 5% 4 6% 10% 42%	2200
	11th to 20th	Day	12% 7% 3 6% 5% 4 4 4 6% 8% 42%	2395
	21st to end	Day	11% 6% 2 7% 5% 5% 4 4 5% 7% 44%	2600
May	1st to 10th	Day	10% 7% 3 9% 7% 6% 6% 5% 7% 8% 32%	5862
	11th to 20th	Day	16% 8% 2 8% 6% 7% 7% 5% 7% 8% 27%	5861
	21st to end	Day	11% 6% 2 7% 5% 6% 6% 5% 7% 9% 37%	6433
June	1st to 10th	Day	10% 7% 3 9% 7% 6% 7% 6% 8% 9% 28%	2600
	11th to 20th	Day	7% 6% 3 8% 6% 7% 7% 6% 8% 9% 31%	2600
	21st to end	Day	7% 6% 3 9% 7% 6% 7% 5% 8% 9% 32%	2600
July	1st to 10th	Day	6% 5% 2 8% 7% 8% 8% 6% 8% 10% 31%	5900
	11th to 20th	Day	8% 7% 3 11% 8% 8% 8% 6% 7% 9% 24%	5900
	21st to end	Day	9% 9% 4 12% 9% 9% 9% 6% 7% 8% 17%	6424
August	1st to 10th	Day	15% 8% 3 9% 7% 8% 7% 6% 8% 10% 20%	4234
	11th to 20th	Day	9% 7% 3 9% 7% 7% 7% 6% 8% 10% 25%	4174
	21st to end	Day	7% 5% 3 8% 6% 6% 7% 5% 7% 8% 39%	4297
September	1st to 10th	Day	10% 7% 3 9% 7% 6% 6% 5% 6% 7% 35%	2200
	11th to 20th	Day	17% 7% 3 9% 5% 5% 6% 4 6% 7% 31%	2200
	21st to end	Day	16% 8% 3 6% 6% 5% 6% 4 5% 6% 36%	2200
October	1st to 10th	Day	14% 7% 2 6% 4 4 4 4 4 6% 47%	2178
	11th to 20th	Day	9% 5% 2 5% 4 3 4 4 4 6% 55%	2000
	21st to end	Day	12% 5% 2 5% 3 3 3 2 5% 5% 55%	2200
November	1st to 10th	Day	9% 8% 2 4 3 3 3 3 4 6% 55%	1950
	11th to 20th	Day	8% 6% 2 4 3 3 4 4 6% 6% 53%	1890
	21st to end	Day	10% 5% 2 6% 4 3 4 4 5% 7% 49%	1890
December	1st to 10th	Day	7% 5% 2 6% 5% 5% 4 3 5% 7% 52%	2948
	11th to 20th	Day	9% 5% 3 6% 4 5% 6% 4 6% 9% 43%	3373
	21st to end	Day	12% 7% 3 5% 3 4 4 4 5% 7% 46%	4466
January	1st to 10th	Night	9% 4 2 5% 4 3 4 3 6% 7% 53%	5889
	11th to 20th	Night	5% 6% 2 5% 3 3 4 4 6% 6% 56%	5900
	21st to end	Night	10% 8% 3 6% 4 4 5% 3 4 5% 48%	6490
February	1st to 10th	Night	8% 7% 3 6% 5% 5% 5% 5% 6% 7% 44%	2490
	11th to 20th	Night	11% 9% 2 6% 5% 5% 4 4 5% 5% 42%	2338
	21st to end	Night	10% 6% 2 6% 6% 6% 5% 4 7% 7% 41%	1980
March	1st to 10th	Night	14% 9% 2 6% 5% 5% 5% 4 6% 6% 38%	5051
	11th to 20th	Night	8% 6% 2 5% 4 4 5% 3 5% 8% 51%	4980
	21st to end	Night	12% 6% 2 7% 5% 5% 5% 4 5% 6% 42%	5467
April	1st to 10th	Night	8% 7% 3 7% 4 4 4 4 7% 7% 46%	2200
	11th to 20th	Night	10% 6% 3 5% 4 4 4 3 5% 7% 49%	1969
	21st to end	Night	8% 7% 2 6% 5% 4 3 4 5% 6% 49%	1800
May	1st to 10th	Night	9% 7% 2 6% 4 6% 6% 6% 8% 10% 36%	4033
	11th to 20th	Night	17% 7% 2 7% 5% 5% 6% 4 7% 10% 29%	4032
	21st to end	Night	12% 6% 2 5% 4 5% 5% 4 7% 9% 40%	4421
June	1st to 10th	Night	8% 6% 2 8% 6% 5% 6% 5% 9% 12% 35%	1800
	11th to 20th	Night	7% 5% 2 6% 5% 4 5% 5% 10% 13% 39%	1800
	21st to end	Night	7% 4 2 5% 5% 5% 6% 5% 7% 12% 42%	1800
July	1st to 10th	Night	5% 5% 2 7% 7% 7% 7% 6% 8% 11% 34%	4058
	11th to 20th	Night	5% 7% 2 7% 5% 6% 7% 5% 9% 13% 33%	4057
	21st to end	Night	9% 9% 3 9% 6% 6% 7% 5% 8% 10% 27%	4427
August	1st to 10th	Night	11% 8% 2 7% 6% 6% 7% 6% 7% 10% 29%	2915
	11th to 20th	Night	10% 9% 3 7% 6% 6% 7% 5% 8% 9% 29%	2875
	21st to end	Night	8% 5% 2 5% 4 4 5% 4 6% 9% 46%	3562
September	1st to 10th	Night	12% 7% 3 7% 4 5% 5% 4 7% 8% 38%	2200
	11th to 20th	Night	17% 9% 3 7% 4 4 4 3 6% 8% 35%	2200
	21st to end	Night	15% 7% 3 6% 3 4 4 3 4 7% 44%	2200
October	1st to 10th	Night	14% 7% 2 5% 4 4 3 3 4 6% 47%	2220
	11th to 20th	Night	11% 7% 2 6% 3 3 4 3 5% 5% 51%	2400
	21st to end	Night	11% 5% 2 5% 3 4 4 4 4 5% 54%	2640
November	1st to 10th	Night	10% 7% 2 5% 4 4 5% 3 5% 5% 50%	2566
	11th to 20th	Night	9% 6% 2 5% 3 4 4 3 5% 8% 51%	2730
	21st to end	Night	10% 5% 2 4 5% 5% 5% 4 6% 6% 48%	2730
December	1st to 10th	Night	7% 6% 2 6% 4 4 5% 4 6% 7% 50%	4277
	11th to 20th	Night	11% 8% 3 7% 5% 4 5% 4 5% 6% 42%	4822
	21st to end	Night	14% 7% 3 5% 4 4 4 3 6% 7% 42%	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	27% 5% 7% 15% 37% 9%	4057
	11th to 20th	Day	28% 4 6% 11% 38% 13%	4060
	21st to end	Day	36% 4 9% 17% 24% 10%	4466
February	1st to 10th	Day	39% 6% 8% 21% 18% 7%	1905
	11th to 20th	Day	41% 7% 9% 16% 20% 6%	1958
	21st to end	Day	41% 7% 10% 14% 20% 8%	1650
March	1st to 10th	Day	41% 5% 6% 15% 19% 14%	4800
	11th to 20th	Day	32% 6% 6% 14% 23% 20%	4980
	21st to end	Day	41% 6% 7% 25% 14% 6%	5465
April	1st to 10th	Day	35% 8% 12% 21% 18% 5%	2200
	11th to 20th	Day	38% 7% 11% 18% 20% 6%	2395
	21st to end	Day	37% 9% 12% 24% 16% 2	2600
May	1st to 10th	Day	46% 9% 13% 19% 11% 1	5897
	11th to 20th	Day	50% 9% 14% 17% 9%	5865
	21st to end	Day	40% 10% 14% 18% 15% 3	6447
June	1st to 10th	Day	47% 13% 15% 18% 6% 1	2600
	11th to 20th	Day	43% 13% 18% 15% 10% 1	2600
	21st to end	Day	43% 11% 15% 18% 10% 2	2600
July	1st to 10th	Day	43% 10% 18% 20% 8%	5835
	11th to 20th	Day	52% 10% 23% 11% 3	5831
	21st to end	Day	59% 10% 16% 9% 5%	6240
August	1st to 10th	Day	55% 8% 16% 18% 3	4221
	11th to 20th	Day	48% 8% 19% 12% 9% 3	4213
	21st to end	Day	41% 7% 13% 27% 12% 1	4297
September	1st to 10th	Day	45% 9% 12% 17% 14% 3	2200
	11th to 20th	Day	50% 8% 10% 17% 14% 2	2200
	21st to end	Day	46% 7% 12% 17% 14% 5%	2200
October	1st to 10th	Day	29% 4 7% 18% 30% 11%	3542
	11th to 20th	Day	21% 3 5% 18% 26% 27%	3240
	21st to end	Day	28% 2 7% 24% 20% 17%	3538
November	1st to 10th	Day	31% 4 8% 19% 27% 10%	1950
	11th to 20th	Day	30% 6% 7% 22% 27% 9%	1890
	21st to end	Day	32% 6% 9% 21% 26% 7%	1890
December	1st to 10th	Day	34% 5% 6% 18% 27% 11%	2948
	11th to 20th	Day	35% 6% 13% 16% 21% 9%	3370
	21st to end	Day	36% 5% 10% 26% 19% 4	4466
January	1st to 10th	Night	28% 5% 9% 15% 31% 12%	5889
	11th to 20th	Night	28% 6% 7% 13% 33% 14%	5900
	21st to end	Night	35% 6% 8% 13% 26% 12%	6490
February	1st to 10th	Night	36% 7% 12% 20% 19% 6%	2490
	11th to 20th	Night	41% 7% 9% 19% 18% 6%	2339
	21st to end	Night	37% 9% 11% 16% 20% 6%	1980
March	1st to 10th	Night	40% 7% 10% 12% 23% 8%	5051
	11th to 20th	Night	28% 7% 7% 19% 22% 18%	4980
	21st to end	Night	39% 6% 10% 23% 15% 6%	5467
April	1st to 10th	Night	34% 7% 13% 22% 20% 3	2200
	11th to 20th	Night	33% 6% 12% 22% 22% 5%	1969
	21st to end	Night	34% 9% 13% 25% 17% 2	1800
May	1st to 10th	Night	41% 11% 15% 24% 8% 1	4060
	11th to 20th	Night	47% 9% 20% 17% 7%	4033
	21st to end	Night	35% 10% 18% 24% 10% 2	4429
June	1st to 10th	Night	38% 15% 20% 20% 7% 1	1800
	11th to 20th	Night	34% 12% 25% 21% 8% 1	1800
	21st to end	Night	32% 13% 21% 19% 12% 3	1800
July	1st to 10th	Night	40% 13% 21% 22% 5%	4015
	11th to 20th	Night	39% 14% 31% 13% 2 1	4006
	21st to end	Night	48% 12% 20% 14% 5%	4297
August	1st to 10th	Night	47% 10% 23% 16% 4	2904
	11th to 20th	Night	45% 9% 22% 14% 10%	2902
	21st to end	Night	33% 9% 17% 31% 10% 1	3562
September	1st to 10th	Night	41% 11% 15% 18% 12% 2	2200
	11th to 20th	Night	48% 8% 13% 17% 14% 1	2200
	21st to end	Night	42% 6% 13% 22% 15% 3	2200
October	1st to 10th	Night	29% 4 9% 20% 28% 10%	3623
	11th to 20th	Night	22% 4 7% 19% 26% 22%	3899
	21st to end	Night	31% 3 7% 22% 22% 16%	4252
November	1st to 10th	Night	33% 7% 9% 19% 23% 9%	2566
	11th to 20th	Night	31% 5% 8% 18% 27% 10%	2730
	21st to end	Night	34% 6% 8% 20% 24% 8%	2730
December	1st to 10th	Night	32% 6% 9% 19% 25% 9%	4277
	11th to 20th	Night	39% 6% 11% 17% 19% 9%	4824
	21st to end	Night	38% 5% 12% 19% 22% 3	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	32% 31% 29% 7% 1	300
	11th to 20th	Day	33% 27% 28% 10% 2	300
	21st to end	Day	24% 38% 30% 7% 2	330
February	1st to 10th	Day	25% 31% 33% 9% 2	300
	11th to 20th	Day	40% 32% 25% 3	300
	21st to end	Day	35% 37% 23% 6%	249
March	1st to 10th	Day	26% 27% 28% 13% 5%	438
	11th to 20th	Day	28% 29% 26% 13% 4 1	500
	21st to end	Day	25% 26% 30% 14% 4	550
April	1st to 10th	Day	23% 26% 27% 17% 6% 1	500
	11th to 20th	Day	19% 26% 26% 19% 9% 2	492
	21st to end	Day	20% 19% 29% 19% 10% 3	500
May	1st to 10th	Day	16% 22% 30% 20% 7% 4	503
	11th to 20th	Day	18% 15% 25% 23% 12% 7%	527
	21st to end	Day	17% 11% 20% 27% 14% 10%	573
June	1st to 10th	Day	15% 8% 26% 27% 15% 10%	530
	11th to 20th	Day	11% 8% 23% 23% 23% 12%	530
	21st to end	Day	10% 7% 27% 27% 18% 11%	530
July	1st to 10th	Day	10% 5% 15% 29% 26% 15%	525
	11th to 20th	Day	10% 4 12% 27% 25% 21%	524
	21st to end	Day	10% 3 13% 27% 28% 18%	576
August	1st to 10th	Day	21% 5% 16% 26% 16% 15%	526
	11th to 20th	Day	12% 6% 15% 30% 23% 14%	519
	21st to end	Day	16% 4 16% 27% 24% 14%	583
September	1st to 10th	Day	13% 4 17% 31% 25% 10%	530
	11th to 20th	Day	21% 6% 15% 27% 23% 8%	530
	21st to end	Day	24% 7% 19% 29% 17% 4	530
October	1st to 10th	Day	22% 9% 19% 25% 18% 7%	530
	11th to 20th	Day	14% 18% 27% 26% 13% 2	530
	21st to end	Day	20% 16% 25% 27% 9% 2	583
November	1st to 10th	Day	21% 18% 31% 19% 9% 2	428
	11th to 20th	Day	18% 27% 36% 15% 4	330
	21st to end	Day	20% 28% 35% 11% 5% 1	330
December	1st to 10th	Day	26% 32% 32% 8% 2	306
	11th to 20th	Day	21% 26% 36% 13% 3 1	300
	21st to end	Day	26% 20% 40% 9% 4 1	330
January	1st to 10th	Night	19% 27% 30% 19% 5% 1	800
	11th to 20th	Night	21% 21% 34% 19% 5%	800
	21st to end	Night	18% 26% 33% 20% 3	880
February	1st to 10th	Night	16% 23% 33% 24% 4	800
	11th to 20th	Night	24% 26% 32% 16% 2	783
	21st to end	Night	19% 29% 32% 18% 2	660
March	1st to 10th	Night	18% 26% 32% 21% 5%	800
	11th to 20th	Night	20% 22% 30% 20% 7% 1	800
	21st to end	Night	20% 22% 32% 18% 8%	880
April	1st to 10th	Night	19% 24% 29% 21% 7% 1	800
	11th to 20th	Night	18% 18% 28% 24% 10% 2	675
	21st to end	Night	12% 16% 27% 31% 13% 1	600
May	1st to 10th	Night	13% 14% 31% 27% 14% 2	600
	11th to 20th	Night	17% 9% 21% 31% 19% 3	591
	21st to end	Night	16% 5% 15% 28% 30% 7%	650
June	1st to 10th	Night	11% 2 19% 37% 27% 6%	600
	11th to 20th	Night	10% 4 14% 28% 34% 11%	600
	21st to end	Night	7% 3 14% 32% 36% 8%	600
July	1st to 10th	Night	12% 2 8% 23% 47% 8%	585
	11th to 20th	Night	10% 2 8% 24% 44% 12%	582
	21st to end	Night	9% 2 7% 28% 42% 12%	657
August	1st to 10th	Night	15% 2 8% 29% 37% 9%	597
	11th to 20th	Night	16% 3 10% 27% 36% 8%	594
	21st to end	Night	15% 3 10% 23% 40% 10%	704
September	1st to 10th	Night	15% 5% 10% 29% 34% 7%	800
	11th to 20th	Night	23% 5% 9% 27% 30% 6%	800
	21st to end	Night	21% 6% 13% 32% 24% 3	800
October	1st to 10th	Night	19% 9% 17% 24% 24% 7%	800
	11th to 20th	Night	19% 11% 25% 26% 16% 3	800
	21st to end	Night	16% 14% 21% 33% 13% 3	880
November	1st to 10th	Night	18% 11% 22% 29% 17% 3	820
	11th to 20th	Night	16% 19% 22% 31% 10% 2	840
	21st to end	Night	18% 17% 23% 30% 11% 1	840
December	1st to 10th	Night	19% 20% 28% 27% 7%	809
	11th to 20th	Night	17% 17% 30% 29% 7% 1	800
	21st to end	Night	22% 18% 28% 27% 4	880

Page generated at 2025-11-30 01:00:51. Version ac07

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