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 2024-04-10.

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% 5% 3 4 5% 6% 8% 44%	83308
	Night	13% 7% 3 5% 5% 3 4 5% 5% 8% 42%	85467
Transparency	Day	38% 7% 15% 22% 14% 3	83026
	Night	41% 7% 13% 21% 15% 3	85269
Seeing	Day	14% 6% 19% 26% 25% 10%	14708
	Night	16% 7% 21% 28% 22% 6%	24504

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	10% 8% 3 6% 5% 3 3 4 4 7% 48%	2781
	11th to 20th	Day	10% 5% 3 5% 6% 3 5% 5% 6% 6% 45%	2840
	21st to end	Day	12% 10% 3 7% 5% 3 4 4 5% 7% 39%	3124
February	1st to 10th	Day	15% 7% 2 4 4 3 4 6% 6% 7% 41%	1761
	11th to 20th	Day	18% 7% 2 6% 6% 2 4 3 5% 6% 41%	1848
	21st to end	Day	14% 6% 3 5% 5% 3 4 5% 6% 7% 42%	1570
March	1st to 10th	Day	22% 10% 3 5% 5% 2 4 3 6% 6% 35%	3297
	11th to 20th	Day	10% 4 2 4 4 2 3 4 4 6% 56%	3480
	21st to end	Day	16% 7% 2 4 4 2 4 4 4 6% 47%	3962
April	1st to 10th	Day	12% 5% 2 4 4 2 4 4 4 6% 52%	2270
	11th to 20th	Day	8% 4 2 5% 4 2 4 5% 6% 8% 50%	2134
	21st to end	Day	8% 4 2 4 4 3 4 4 6% 8% 53%	2160
May	1st to 10th	Day	10% 5% 2 4 5% 2 6% 5% 6% 9% 46%	2160
	11th to 20th	Day	14% 6% 2 6% 4 3 5% 4 6% 9% 41%	2185
	21st to end	Day	9% 5% 2 5% 5% 2 5% 5% 7% 10% 44%	2725
June	1st to 10th	Day	9% 5% 3 6% 5% 4 6% 5% 6% 10% 41%	2520
	11th to 20th	Day	9% 4 2 4 5% 3 5% 5% 8% 11% 45%	2520
	21st to end	Day	7% 4 2 6% 6% 3 6% 8% 8% 11% 39%	2520
July	1st to 10th	Day	9% 5% 2 5% 4 3 5% 6% 8% 11% 42%	2484
	11th to 20th	Day	8% 6% 2 5% 5% 3 5% 5% 8% 13% 40%	2340
	21st to end	Day	8% 6% 3 5% 6% 3 6% 6% 8% 11% 37%	2547
August	1st to 10th	Day	11% 6% 2 5% 5% 4 5% 6% 7% 11% 37%	2224
	11th to 20th	Day	10% 6% 2 6% 5% 3 4 6% 7% 11% 40%	2126
	21st to end	Day	12% 6% 3 6% 7% 4 6% 5% 8% 9% 35%	2376
September	1st to 10th	Day	12% 6% 3 6% 7% 3 5% 5% 6% 9% 39%	2160
	11th to 20th	Day	13% 6% 3 6% 6% 4 5% 6% 6% 7% 37%	2156
	21st to end	Day	19% 7% 3 6% 5% 3 4 4 5% 6% 37%	1958
October	1st to 10th	Day	14% 6% 3 5% 5% 3 5% 3 5% 5% 47%	1800
	11th to 20th	Day	14% 6% 2 5% 4 2 4 3 4 6% 50%	1800
	21st to end	Day	12% 5% 2 4 5% 3 4 4 5% 6% 51%	1980
November	1st to 10th	Day	16% 6% 2 5% 5% 3 4 4 5% 7% 45%	1800
	11th to 20th	Day	15% 5% 2 5% 4 2 4 4 5% 7% 48%	1710
	21st to end	Day	13% 5% 3 5% 5% 2 4 5% 5% 7% 47%	1710
December	1st to 10th	Day	16% 6% 4 6% 5% 3 6% 5% 5% 7% 37%	1598
	11th to 20th	Day	16% 5% 2 5% 4 2 3 3 4 5% 51%	1910
	21st to end	Day	12% 6% 3 5% 4 3 4 4 5% 7% 46%	2772
January	1st to 10th	Night	13% 7% 3 5% 4 3 4 4 5% 7% 45%	4160
	11th to 20th	Night	14% 7% 2 5% 5% 4 5% 5% 6% 7% 40%	4120
	21st to end	Night	13% 7% 3 5% 6% 3 5% 5% 5% 7% 42%	4532
February	1st to 10th	Night	19% 7% 2 4 4 3 4 5% 5% 7% 40%	2418
	11th to 20th	Night	18% 9% 3 6% 5% 2 4 4 5% 6% 38%	2218
	21st to end	Night	17% 7% 2 6% 6% 3 5% 4 4 6% 41%	1884
March	1st to 10th	Night	20% 11% 4 7% 6% 3 5% 4 4 6% 30%	3552
	11th to 20th	Night	11% 6% 2 5% 5% 2 4 4 5% 7% 48%	3480
	21st to end	Night	16% 8% 3 5% 4 2 3 3 4 5% 48%	3668
April	1st to 10th	Night	12% 6% 2 5% 4 3 4 4 5% 7% 48%	1900
	11th to 20th	Night	8% 5% 3 6% 4 3 6% 6% 7% 6% 46%	1775
	21st to end	Night	10% 4 2 4 5% 4 4 4 5% 7% 52%	1800
May	1st to 10th	Night	11% 6% 3 4 5% 4 4 5% 6% 10% 42%	1800
	11th to 20th	Night	15% 6% 3 4 5% 3 4 4 5% 10% 43%	1718
	21st to end	Night	10% 5% 2 4 5% 3 4 4 6% 10% 45%	1550
June	1st to 10th	Night	12% 5% 2 5% 5% 4 6% 5% 7% 10% 40%	1440
	11th to 20th	Night	8% 4 2 4 5% 3 6% 6% 6% 13% 42%	1440
	21st to end	Night	9% 6% 2 4 6% 4 6% 6% 7% 12% 38%	1440
July	1st to 10th	Night	8% 5% 2 5% 6% 4 6% 7% 9% 13% 36%	1470
	11th to 20th	Night	8% 6% 3 6% 6% 3 5% 6% 6% 11% 41%	1620
	21st to end	Night	8% 6% 3 6% 6% 4 6% 7% 8% 12% 33%	1771
August	1st to 10th	Night	10% 5% 2 6% 7% 4 5% 7% 8% 12% 34%	1696
	11th to 20th	Night	9% 6% 2 6% 6% 5% 6% 6% 7% 10% 37%	1774
	21st to end	Night	13% 7% 2 6% 6% 3 5% 6% 8% 11% 34%	1980
September	1st to 10th	Night	12% 5% 2 6% 6% 4 6% 6% 8% 9% 35%	1800
	11th to 20th	Night	15% 7% 3 7% 6% 3 4 3 5% 8% 37%	1804
	21st to end	Night	19% 8% 3 6% 6% 4 5% 4 5% 6% 34%	1998
October	1st to 10th	Night	12% 6% 3 6% 5% 3 4 3 5% 7% 46%	2160
	11th to 20th	Night	15% 6% 3 4 4 3 4 4 5% 6% 47%	2160
	21st to end	Night	12% 4 3 5% 4 2 5% 4 4 7% 50%	2376
November	1st to 10th	Night	14% 7% 3 5% 5% 3 4 5% 5% 6% 44%	2275
	11th to 20th	Night	17% 7% 3 5% 5% 3 3 4 5% 7% 42%	2470
	21st to end	Night	13% 6% 2 5% 5% 2 4 4 5% 7% 48%	2470
December	1st to 10th	Night	15% 8% 3 6% 5% 3 4 5% 5% 7% 38%	2579
	11th to 20th	Night	14% 7% 3 5% 5% 2 4 4 5% 6% 46%	3285
	21st to end	Night	12% 7% 3 5% 4 3 3 4 5% 7% 46%	4884

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	37% 6% 9% 29% 17% 2	2782
	11th to 20th	Day	38% 6% 8% 24% 19% 5%	2840
	21st to end	Day	45% 7% 11% 18% 15% 5%	3124
February	1st to 10th	Day	42% 5% 14% 23% 14% 2	1761
	11th to 20th	Day	46% 4 10% 18% 18% 4	1857
	21st to end	Day	41% 6% 14% 20% 15% 5%	1570
March	1st to 10th	Day	51% 5% 12% 14% 12% 6%	3297
	11th to 20th	Day	30% 5% 11% 19% 22% 12%	3480
	21st to end	Day	38% 6% 11% 25% 16% 4	3962
April	1st to 10th	Day	33% 6% 14% 22% 21% 4	2270
	11th to 20th	Day	32% 6% 14% 27% 16% 5%	2134
	21st to end	Day	29% 7% 15% 29% 18% 3	2160
May	1st to 10th	Day	34% 8% 19% 22% 14% 2	2160
	11th to 20th	Day	40% 8% 17% 26% 8% 1	2189
	21st to end	Day	34% 10% 18% 27% 10% 1	2725
June	1st to 10th	Day	38% 9% 18% 23% 11%	2520
	11th to 20th	Day	31% 11% 21% 27% 9%	2520
	21st to end	Day	35% 12% 21% 23% 8%	2520
July	1st to 10th	Day	34% 10% 24% 25% 8%	2416
	11th to 20th	Day	32% 12% 27% 22% 7%	2271
	21st to end	Day	37% 10% 23% 24% 6%	2405
August	1st to 10th	Day	39% 11% 27% 18% 5%	2211
	11th to 20th	Day	37% 12% 22% 20% 9%	2126
	21st to end	Day	43% 10% 20% 18% 8% 1	2376
September	1st to 10th	Day	40% 11% 19% 17% 12% 1	2160
	11th to 20th	Day	44% 9% 13% 19% 13% 2	2156
	21st to end	Day	48% 6% 11% 18% 16% 1	1958
October	1st to 10th	Day	39% 5% 11% 23% 21% 1	1800
	11th to 20th	Day	36% 6% 9% 23% 21% 5%	1800
	21st to end	Day	34% 6% 9% 23% 24% 4	1980
November	1st to 10th	Day	40% 7% 9% 20% 21% 4	1800
	11th to 20th	Day	38% 4 11% 21% 21% 5%	1710
	21st to end	Day	37% 5% 13% 23% 20% 3	1710
December	1st to 10th	Day	46% 7% 14% 19% 11% 3	1598
	11th to 20th	Day	39% 4 9% 23% 20% 5%	1906
	21st to end	Day	38% 5% 14% 24% 17% 2	2772
January	1st to 10th	Night	38% 6% 9% 24% 19% 3	4160
	11th to 20th	Night	43% 5% 10% 21% 16% 5%	4120
	21st to end	Night	41% 7% 10% 19% 19% 4	4532
February	1st to 10th	Night	43% 5% 11% 22% 15% 4	2418
	11th to 20th	Night	47% 5% 10% 16% 17% 4	2220
	21st to end	Night	45% 5% 11% 18% 16% 5%	1884
March	1st to 10th	Night	57% 5% 9% 15% 12% 2	3552
	11th to 20th	Night	35% 7% 10% 14% 21% 12%	3480
	21st to end	Night	40% 5% 10% 25% 15% 5%	3668
April	1st to 10th	Night	37% 5% 14% 19% 21% 5%	1900
	11th to 20th	Night	37% 5% 14% 24% 16% 5%	1775
	21st to end	Night	32% 7% 13% 30% 16% 4	1800
May	1st to 10th	Night	37% 8% 17% 21% 15% 2	1800
	11th to 20th	Night	39% 7% 17% 22% 14% 1	1719
	21st to end	Night	34% 8% 19% 28% 10% 1	1551
June	1st to 10th	Night	39% 9% 18% 23% 10% 1	1440
	11th to 20th	Night	33% 10% 21% 25% 10% 1	1440
	21st to end	Night	37% 11% 21% 23% 8%	1440
July	1st to 10th	Night	36% 12% 23% 21% 8%	1429
	11th to 20th	Night	37% 10% 25% 23% 6%	1566
	21st to end	Night	39% 12% 22% 22% 5%	1672
August	1st to 10th	Night	40% 11% 27% 19% 3	1685
	11th to 20th	Night	39% 11% 21% 17% 10% 1	1774
	21st to end	Night	42% 11% 21% 18% 8% 1	1980
September	1st to 10th	Night	43% 10% 16% 18% 12% 1	1800
	11th to 20th	Night	47% 8% 14% 19% 12% 1	1804
	21st to end	Night	50% 7% 10% 19% 13%	1998
October	1st to 10th	Night	38% 6% 10% 24% 20% 2	2160
	11th to 20th	Night	38% 5% 9% 24% 19% 4	2160
	21st to end	Night	34% 5% 9% 24% 24% 5%	2376
November	1st to 10th	Night	42% 6% 10% 19% 19% 4	2275
	11th to 20th	Night	43% 5% 10% 17% 20% 5%	2470
	21st to end	Night	37% 4 11% 24% 20% 4	2470
December	1st to 10th	Night	46% 6% 13% 17% 14% 3	2579
	11th to 20th	Night	40% 5% 10% 20% 20% 5%	3288
	21st to end	Night	38% 5% 13% 24% 18% 2	4884

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	16% 14% 38% 23% 9%	256
	11th to 20th	Day	16% 9% 33% 33% 10% 1	270
	21st to end	Day	16% 12% 34% 26% 11% 1	297
February	1st to 10th	Day	18% 8% 32% 30% 11% 1	321
	11th to 20th	Day	22% 12% 34% 27% 5%	456
	21st to end	Day	16% 9% 33% 30% 10% 2	382
March	1st to 10th	Day	16% 10% 35% 26% 13% 1	460
	11th to 20th	Day	17% 10% 33% 27% 12% 1	460
	21st to end	Day	16% 7% 34% 28% 12% 3	506
April	1st to 10th	Day	16% 9% 30% 28% 14% 2	457
	11th to 20th	Day	9% 6% 27% 29% 25% 5%	412
	21st to end	Day	9% 4 25% 35% 22% 5%	420
May	1st to 10th	Day	12% 5% 23% 33% 21% 6%	423
	11th to 20th	Day	17% 2 12% 32% 27% 10%	447
	21st to end	Day	13% 2 8% 25% 31% 20%	485
June	1st to 10th	Day	12% 2 9% 33% 35% 9%	450
	11th to 20th	Day	10% 3 9% 24% 35% 18%	450
	21st to end	Day	8% 2 10% 24% 41% 15%	450
July	1st to 10th	Day	11% 4 5% 18% 43% 20%	445
	11th to 20th	Day	9% 2 4 18% 45% 23%	444
	21st to end	Day	9% 2 4 24% 46% 14%	488
August	1st to 10th	Day	12% 2 5% 24% 38% 19%	446
	11th to 20th	Day	11% 3 2 18% 41% 26%	439
	21st to end	Day	14% 3 4 20% 42% 17%	495
September	1st to 10th	Day	12% 3 8% 21% 32% 25%	450
	11th to 20th	Day	14% 4 10% 24% 35% 13%	450
	21st to end	Day	23% 3 10% 25% 27% 13%	450
October	1st to 10th	Day	18% 5% 12% 22% 30% 13%	450
	11th to 20th	Day	14% 4 18% 30% 25% 8%	450
	21st to end	Day	11% 6% 21% 28% 26% 7%	495
November	1st to 10th	Day	17% 7% 19% 27% 24% 6%	428
	11th to 20th	Day	19% 5% 28% 32% 12% 3	370
	21st to end	Day	14% 9% 25% 31% 18% 3	370
December	1st to 10th	Day	17% 7% 38% 25% 11% 2	258
	11th to 20th	Day	18% 8% 33% 24% 16% 2	180
	21st to end	Day	17% 6% 30% 29% 15% 2	198
January	1st to 10th	Night	16% 16% 33% 25% 10% 1	760
	11th to 20th	Night	16% 13% 29% 29% 13% 1	760
	21st to end	Night	20% 13% 34% 27% 6%	836
February	1st to 10th	Night	21% 10% 31% 29% 8% 1	760
	11th to 20th	Night	22% 14% 32% 24% 7%	743
	21st to end	Night	19% 12% 30% 28% 9% 1	628
March	1st to 10th	Night	15% 11% 32% 29% 11% 1	760
	11th to 20th	Night	16% 10% 31% 30% 11% 3	760
	21st to end	Night	17% 11% 28% 29% 13% 2	836
April	1st to 10th	Night	14% 9% 32% 30% 13% 1	760
	11th to 20th	Night	11% 6% 27% 31% 21% 5%	711
	21st to end	Night	12% 4 23% 37% 22% 2	720
May	1st to 10th	Night	16% 5% 20% 37% 18% 4	720
	11th to 20th	Night	16% 4 20% 32% 21% 8%	657
	21st to end	Night	13% 3 7% 29% 34% 15%	389
June	1st to 10th	Night	13% 2 11% 34% 33% 7%	360
	11th to 20th	Night	9% 2 8% 29% 42% 11%	360
	21st to end	Night	10% 2 8% 35% 37% 8%	360
July	1st to 10th	Night	7% 1 4 31% 44% 13%	379
	11th to 20th	Night	11% 2 4 19% 47% 16%	522
	21st to end	Night	10% 3 5% 28% 47% 8%	591
August	1st to 10th	Night	12% 2 5% 27% 42% 12%	622
	11th to 20th	Night	12% 3 3 26% 38% 19%	710
	21st to end	Night	14% 2 4 21% 42% 16%	792
September	1st to 10th	Night	13% 2 6% 19% 39% 19%	720
	11th to 20th	Night	18% 3 8% 26% 35% 10%	720
	21st to end	Night	23% 3 8% 26% 31% 9%	720
October	1st to 10th	Night	14% 3 13% 26% 33% 11%	720
	11th to 20th	Night	18% 5% 19% 28% 24% 6%	720
	21st to end	Night	14% 7% 22% 27% 24% 5%	792
November	1st to 10th	Night	16% 6% 19% 33% 21% 5%	740
	11th to 20th	Night	20% 7% 21% 33% 17% 2	760
	21st to end	Night	15% 9% 26% 28% 19% 3	760
December	1st to 10th	Night	19% 11% 28% 26% 15% 1	760
	11th to 20th	Night	17% 10% 31% 30% 10% 3	760
	21st to end	Night	17% 11% 29% 31% 11% 1	836

Page generated at 2024-04-07 09:28:12. Version ac07

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