Ocracoke Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ocracoke Campground clear sky chart from 2005-11-06 to 2025-10-19.

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	11% 6% 2 6% 4 4 5% 4 6% 8% 42%	125860
	Night	12% 7% 2 6% 4 4 4 4 6% 8% 42%	123832
Transparency	Day	38% 7% 16% 22% 14% 3	129457
	Night	39% 7% 14% 20% 16% 4	128305
Seeing	Day	14% 6% 19% 27% 26% 9%	16815
	Night	15% 7% 21% 28% 23% 6%	26469

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	9% 7% 3 6% 3 3 3 2 3 6% 54%	3987
	11th to 20th	Day	12% 5% 2 5% 4 3 4 3 5% 5% 51%	4060
	21st to end	Day	12% 12% 4 9% 4 4 4 3 5% 5% 38%	4466
February	1st to 10th	Day	16% 8% 2 5% 4 4 5% 4 6% 7% 40%	1854
	11th to 20th	Day	19% 8% 2 7% 4 3 3 3 5% 5% 41%	1948
	21st to end	Day	13% 6% 2 5% 4 5% 3 4 6% 7% 44%	1650
March	1st to 10th	Day	18% 9% 3 6% 4 4 4 3 6% 6% 38%	4727
	11th to 20th	Day	9% 5% 2 5% 3 4 5% 3 4 6% 54%	4980
	21st to end	Day	12% 6% 1 5% 3 3 4 3 4 6% 52%	5682
April	1st to 10th	Day	12% 6% 2 5% 4 4 4 3 5% 6% 51%	2400
	11th to 20th	Day	8% 5% 2 5% 4 4 4 5% 6% 8% 51%	2374
	21st to end	Day	8% 4 2 4 4 4 4 3 7% 8% 54%	2400
May	1st to 10th	Day	7% 6% 2 7% 5% 5% 6% 4 7% 9% 40%	5405
	11th to 20th	Day	16% 9% 3 8% 5% 5% 5% 4 7% 9% 31%	5591
	21st to end	Day	11% 6% 2 6% 4 4 5% 4 6% 10% 42%	6934
June	1st to 10th	Day	9% 6% 2 7% 4 6% 5% 4 7% 10% 41%	2800
	11th to 20th	Day	8% 4 2 4 4 5% 5% 4 8% 11% 45%	2800
	21st to end	Day	6% 4 2 6% 5% 5% 6% 5% 8% 11% 41%	2800
July	1st to 10th	Day	7% 5% 2 7% 5% 6% 6% 5% 9% 13% 35%	6254
	11th to 20th	Day	5% 5% 2 8% 6% 6% 6% 6% 9% 13% 35%	5900
	21st to end	Day	7% 6% 3 7% 5% 5% 6% 5% 9% 12% 33%	6424
August	1st to 10th	Day	14% 12% 4 10% 6% 5% 4 4 7% 9% 26%	4042
	11th to 20th	Day	8% 5% 2 6% 5% 4 5% 5% 7% 9% 44%	3850
	21st to end	Day	8% 6% 3 7% 4 5% 5% 4 8% 9% 42%	4312
September	1st to 10th	Day	13% 6% 2 7% 5% 4 5% 4 6% 8% 39%	2400
	11th to 20th	Day	15% 7% 2 7% 5% 6% 5% 5% 6% 7% 36%	2394
	21st to end	Day	19% 8% 3 7% 4 4 4 3 5% 6% 37%	2175
October	1st to 10th	Day	13% 6% 2 6% 4 4 4 3 5% 5% 47%	2000
	11th to 20th	Day	14% 6% 2 5% 4 4 3 2 4 5% 50%	1980
	21st to end	Day	11% 5% 2 5% 4 3 4 3 5% 6% 52%	2090
November	1st to 10th	Day	15% 6% 2 5% 4 4 4 3 5% 7% 45%	1897
	11th to 20th	Day	15% 6% 2 5% 4 3 3 3 5% 7% 47%	1800
	21st to end	Day	12% 6% 2 6% 4 3 4 4 5% 7% 48%	1800
December	1st to 10th	Day	10% 5% 3 5% 4 4 4 3 4 6% 51%	2734
	11th to 20th	Day	12% 6% 3 7% 5% 4 4 3 5% 6% 44%	2990
	21st to end	Day	11% 5% 2 5% 4 4 4 3 5% 8% 50%	3960
January	1st to 10th	Night	10% 7% 3 5% 3 3 3 3 5% 5% 53%	5954
	11th to 20th	Night	12% 6% 2 6% 4 4 4 3 5% 6% 49%	5900
	21st to end	Night	12% 7% 3 7% 4 4 4 3 5% 6% 43%	6490
February	1st to 10th	Night	19% 8% 2 5% 3 4 4 4 5% 6% 40%	2545
	11th to 20th	Night	17% 10% 3 7% 4 3 4 4 6% 5% 38%	2338
	21st to end	Night	16% 7% 2 6% 5% 4 4 4 4 6% 42%	1980
March	1st to 10th	Night	16% 9% 3 8% 5% 4 4 3 4 5% 39%	5108
	11th to 20th	Night	13% 5% 2 5% 4 3 3 3 6% 6% 48%	4980
	21st to end	Night	13% 8% 2 6% 3 3 3 3 4 5% 49%	5248
April	1st to 10th	Night	12% 6% 2 6% 3 4 5% 3 5% 7% 48%	2000
	11th to 20th	Night	8% 6% 2 6% 4 4 5% 4 7% 7% 47%	1975
	21st to end	Night	9% 4 2 5% 5% 4 4 4 6% 7% 51%	2000
May	1st to 10th	Night	7% 7% 3 7% 6% 6% 6% 5% 7% 11% 36%	4490
	11th to 20th	Night	15% 8% 3 7% 5% 5% 5% 4 7% 10% 31%	4326
	21st to end	Night	12% 9% 3 7% 5% 4 5% 4 7% 10% 35%	3920
June	1st to 10th	Night	11% 5% 2 6% 4 5% 5% 4 7% 10% 39%	1600
	11th to 20th	Night	7% 5% 2 5% 5% 5% 6% 5% 7% 12% 42%	1600
	21st to end	Night	8% 6% 2 5% 6% 5% 5% 5% 8% 11% 40%	1600
July	1st to 10th	Night	5% 5% 2 8% 5% 6% 6% 5% 8% 13% 36%	3684
	11th to 20th	Night	6% 5% 2 7% 6% 7% 7% 6% 10% 14% 29%	4057
	21st to end	Night	9% 5% 2 7% 5% 6% 6% 6% 10% 14% 31%	4427
August	1st to 10th	Night	11% 10% 4 10% 6% 5% 5% 5% 7% 11% 26%	3075
	11th to 20th	Night	6% 6% 2 7% 5% 6% 6% 4 8% 10% 39%	3197
	21st to end	Night	8% 5% 2 6% 5% 5% 5% 5% 8% 10% 40%	3586
September	1st to 10th	Night	12% 6% 2 7% 6% 5% 6% 5% 8% 8% 34%	2000
	11th to 20th	Night	16% 9% 3 8% 5% 4 4 3 6% 7% 35%	2005
	21st to end	Night	18% 9% 2 7% 5% 5% 5% 4 5% 6% 34%	2220
October	1st to 10th	Night	12% 7% 2 7% 4 4 4 3 5% 7% 44%	2400
	11th to 20th	Night	16% 7% 2 4 3 3 4 3 5% 6% 47%	2377
	21st to end	Night	12% 4 2 5% 4 3 4 3 4 6% 52%	2508
November	1st to 10th	Night	14% 7% 2 6% 4 4 4 3 5% 6% 43%	2398
	11th to 20th	Night	17% 7% 2 6% 4 4 4 3 5% 6% 41%	2600
	21st to end	Night	12% 6% 2 6% 4 3 4 3 5% 7% 48%	2600
December	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 3 5% 55%	4443
	11th to 20th	Night	13% 7% 3 7% 5% 4 4 4 5% 7% 40%	5205
	21st to end	Night	12% 7% 2 5% 4 4 4 3 5% 7% 47%	6996

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	34% 4 6% 25% 24% 7%	3988
	11th to 20th	Day	35% 5% 6% 22% 27% 7%	4060
	21st to end	Day	48% 5% 9% 15% 18% 5%	4466
February	1st to 10th	Day	43% 5% 13% 23% 14% 2	1854
	11th to 20th	Day	47% 4 10% 18% 17% 4	1957
	21st to end	Day	39% 5% 13% 21% 16% 5%	1650
March	1st to 10th	Day	48% 4 11% 15% 17% 6%	4727
	11th to 20th	Day	32% 5% 9% 19% 21% 14%	4980
	21st to end	Day	34% 5% 13% 24% 19% 5%	5682
April	1st to 10th	Day	33% 6% 14% 21% 21% 4	2400
	11th to 20th	Day	31% 6% 14% 29% 16% 5%	2374
	21st to end	Day	28% 6% 16% 29% 18% 3	2400
May	1st to 10th	Day	37% 9% 22% 24% 8% 1	5437
	11th to 20th	Day	47% 10% 17% 20% 5%	5595
	21st to end	Day	36% 8% 15% 30% 10%	6949
June	1st to 10th	Day	37% 9% 18% 23% 12% 1	2800
	11th to 20th	Day	31% 11% 20% 28% 10%	2800
	21st to end	Day	33% 12% 21% 26% 8%	2800
July	1st to 10th	Day	38% 9% 31% 18% 4	6186
	11th to 20th	Day	37% 14% 33% 12% 3	5831
	21st to end	Day	40% 13% 20% 22% 6%	6240
August	1st to 10th	Day	54% 8% 24% 11% 3	4029
	11th to 20th	Day	34% 10% 18% 26% 11%	3886
	21st to end	Day	37% 8% 21% 25% 9% 1	4312
September	1st to 10th	Day	41% 10% 18% 17% 12% 2	2400
	11th to 20th	Day	46% 9% 13% 19% 12% 1	2394
	21st to end	Day	48% 6% 13% 18% 15% 1	2175
October	1st to 10th	Day	36% 4 8% 23% 23% 6%	3260
	11th to 20th	Day	30% 4 7% 19% 23% 17%	3220
	21st to end	Day	26% 5% 8% 34% 22% 5%	3428
November	1st to 10th	Day	39% 7% 9% 21% 20% 3	1897
	11th to 20th	Day	38% 4 10% 22% 20% 5%	1800
	21st to end	Day	37% 5% 13% 23% 20% 3	1800
December	1st to 10th	Day	35% 5% 10% 20% 27% 4	2734
	11th to 20th	Day	41% 5% 13% 20% 16% 4	2986
	21st to end	Day	34% 5% 17% 28% 15% 1	3960
January	1st to 10th	Night	33% 4 7% 20% 31% 5%	5954
	11th to 20th	Night	37% 4 8% 19% 27% 6%	5900
	21st to end	Night	40% 5% 10% 19% 22% 4	6490
February	1st to 10th	Night	44% 5% 11% 21% 14% 4	2545
	11th to 20th	Night	47% 6% 10% 16% 17% 4	2340
	21st to end	Night	44% 4 10% 18% 18% 6%	1980
March	1st to 10th	Night	48% 4 9% 17% 17% 6%	5108
	11th to 20th	Night	36% 5% 10% 13% 23% 13%	4980
	21st to end	Night	38% 4 11% 25% 18% 4	5248
April	1st to 10th	Night	37% 5% 14% 20% 20% 5%	2000
	11th to 20th	Night	36% 5% 13% 25% 16% 5%	1975
	21st to end	Night	32% 7% 13% 30% 15% 3	2000
May	1st to 10th	Night	39% 9% 21% 22% 8% 1	4520
	11th to 20th	Night	46% 10% 16% 19% 9%	4327
	21st to end	Night	42% 8% 17% 24% 9%	3927
June	1st to 10th	Night	38% 9% 19% 22% 11% 1	1600
	11th to 20th	Night	33% 10% 20% 26% 11% 1	1600
	21st to end	Night	36% 11% 21% 26% 7%	1600
July	1st to 10th	Night	36% 10% 32% 18% 3	3645
	11th to 20th	Night	40% 15% 28% 14% 2	4006
	21st to end	Night	38% 14% 21% 19% 7%	4297
August	1st to 10th	Night	51% 8% 25% 14% 2	3064
	11th to 20th	Night	37% 11% 19% 23% 9%	3227
	21st to end	Night	36% 9% 18% 28% 9% 1	3586
September	1st to 10th	Night	44% 10% 15% 19% 12% 1	2000
	11th to 20th	Night	49% 8% 13% 17% 12% 1	2005
	21st to end	Night	49% 7% 13% 19% 11%	2220
October	1st to 10th	Night	39% 5% 8% 20% 24% 4	3920
	11th to 20th	Night	32% 3 6% 18% 20% 21%	3876
	21st to end	Night	25% 4 8% 34% 24% 6%	4120
November	1st to 10th	Night	41% 6% 10% 20% 19% 4	2398
	11th to 20th	Night	44% 5% 10% 18% 20% 4	2600
	21st to end	Night	37% 4 10% 24% 20% 4	2600
December	1st to 10th	Night	33% 4 9% 16% 31% 8%	4443
	11th to 20th	Night	43% 7% 15% 15% 16% 5%	5208
	21st to end	Night	36% 5% 16% 27% 15% 1	6996

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	15% 15% 40% 22% 8%	285
	11th to 20th	Day	16% 9% 34% 32% 9% 1	300
	21st to end	Day	17% 12% 35% 25% 10% 1	330
February	1st to 10th	Day	19% 9% 31% 29% 11% 1	354
	11th to 20th	Day	24% 13% 33% 25% 5%	496
	21st to end	Day	15% 8% 32% 32% 11% 2	414
March	1st to 10th	Day	16% 11% 34% 26% 12% 1	500
	11th to 20th	Day	17% 10% 33% 28% 11% 1	500
	21st to end	Day	15% 7% 34% 29% 12% 3	550
April	1st to 10th	Day	15% 9% 30% 29% 14% 2	500
	11th to 20th	Day	9% 6% 26% 30% 24% 4	492
	21st to end	Day	8% 3 23% 34% 25% 6%	500
May	1st to 10th	Day	11% 5% 21% 34% 22% 7%	503
	11th to 20th	Day	17% 3 14% 33% 24% 9%	527
	21st to end	Day	13% 3 10% 26% 29% 18%	573
June	1st to 10th	Day	11% 2 10% 33% 35% 8%	530
	11th to 20th	Day	9% 3 8% 26% 38% 16%	530
	21st to end	Day	7% 2 9% 22% 43% 18%	530
July	1st to 10th	Day	10% 4 5% 18% 44% 19%	525
	11th to 20th	Day	8% 2 4 18% 46% 23%	524
	21st to end	Day	9% 3 5% 22% 45% 16%	576
August	1st to 10th	Day	14% 2 6% 24% 37% 17%	526
	11th to 20th	Day	11% 2 3 20% 40% 24%	519
	21st to end	Day	14% 3 5% 22% 39% 17%	583
September	1st to 10th	Day	14% 3 9% 22% 31% 21%	530
	11th to 20th	Day	17% 4 10% 24% 33% 12%	530
	21st to end	Day	22% 3 9% 26% 29% 11%	530
October	1st to 10th	Day	17% 5% 13% 23% 31% 11%	530
	11th to 20th	Day	16% 5% 17% 32% 24% 7%	522
	21st to end	Day	11% 6% 19% 27% 27% 9%	539
November	1st to 10th	Day	17% 7% 19% 28% 25% 5%	465
	11th to 20th	Day	19% 6% 28% 33% 12% 3	400
	21st to end	Day	14% 10% 26% 30% 18% 3	400
December	1st to 10th	Day	16% 7% 38% 27% 11% 1	282
	11th to 20th	Day	17% 8% 34% 26% 15% 2	200
	21st to end	Day	16% 6% 31% 30% 15% 2	220
January	1st to 10th	Night	16% 18% 32% 24% 9% 1	800
	11th to 20th	Night	15% 14% 30% 28% 12% 1	800
	21st to end	Night	19% 12% 35% 27% 6%	880
February	1st to 10th	Night	22% 11% 31% 29% 7% 1	800
	11th to 20th	Night	22% 15% 32% 24% 6%	783
	21st to end	Night	19% 12% 30% 29% 9% 1	660
March	1st to 10th	Night	15% 12% 32% 29% 11% 1	800
	11th to 20th	Night	16% 10% 30% 31% 11% 3	800
	21st to end	Night	16% 11% 29% 30% 12% 2	880
April	1st to 10th	Night	14% 9% 32% 30% 14% 1	800
	11th to 20th	Night	10% 6% 27% 32% 20% 4	791
	21st to end	Night	12% 4 23% 36% 23% 3	800
May	1st to 10th	Night	15% 5% 20% 37% 19% 4	800
	11th to 20th	Night	16% 4 20% 32% 21% 7%	729
	21st to end	Night	13% 3 9% 29% 33% 14%	433
June	1st to 10th	Night	13% 3 12% 34% 33% 7%	400
	11th to 20th	Night	9% 2 8% 30% 42% 10%	400
	21st to end	Night	9% 2 7% 34% 38% 10%	400
July	1st to 10th	Night	7% 1 5% 30% 45% 13%	423
	11th to 20th	Night	10% 2 4 20% 47% 16%	582
	21st to end	Night	10% 2 5% 27% 47% 9%	657
August	1st to 10th	Night	12% 2 6% 27% 41% 11%	692
	11th to 20th	Night	12% 3 4 25% 38% 19%	790
	21st to end	Night	14% 3 4 23% 41% 15%	880
September	1st to 10th	Night	15% 2 8% 20% 38% 18%	800
	11th to 20th	Night	19% 3 8% 27% 34% 10%	800
	21st to end	Night	22% 3 8% 26% 34% 8%	800
October	1st to 10th	Night	15% 3 13% 26% 33% 11%	800
	11th to 20th	Night	19% 5% 20% 27% 23% 6%	793
	21st to end	Night	14% 7% 21% 27% 25% 6%	836
November	1st to 10th	Night	15% 6% 18% 34% 22% 5%	780
	11th to 20th	Night	20% 8% 21% 33% 17% 2	800
	21st to end	Night	15% 10% 26% 27% 19% 3	800
December	1st to 10th	Night	19% 11% 30% 26% 14% 1	800
	11th to 20th	Night	17% 10% 31% 30% 11% 3	800
	21st to end	Night	17% 10% 29% 32% 11% 1	880

Page generated at 2025-10-16 01:50:28. Version ac07

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