High Point State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the High Point State Park clear sky chart from 2005-11-06 to 2025-11-18.

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	17% 7% 3 6% 5% 4 5% 4 6% 7% 37%	127058
	Night	17% 7% 3 6% 4 4 4 3 5% 7% 39%	123327
Transparency	Day	28% 39% 7% 14% 9% 1	130559
	Night	28% 39% 8% 14% 10% 2	127900
Seeing	Day	24% 17% 29% 19% 9% 3	16236
	Night	21% 16% 29% 25% 9% 1	25386

By Month

Percentage Cloud Cover NE (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	12% 9% 3 9% 5% 4 4 4 6% 6% 37%	3597
	11th to 20th	Day	14% 10% 4 10% 6% 5% 4 3 5% 5% 33%	3570
	21st to end	Day	18% 9% 3 6% 5% 4 5% 3 5% 5% 38%	4355
February	1st to 10th	Day	15% 8% 4 8% 5% 5% 5% 4 5% 6% 34%	1800
	11th to 20th	Day	14% 9% 3 7% 5% 5% 4 4 5% 6% 39%	1904
	21st to end	Day	18% 9% 3 8% 4 4 4 3 5% 6% 36%	1650
March	1st to 10th	Day	22% 8% 3 6% 4 4 3 3 4 5% 38%	4476
	11th to 20th	Day	12% 8% 3 7% 5% 4 4 3 5% 7% 41%	4878
	21st to end	Day	19% 8% 2 6% 4 4 4 3 4 6% 40%	5868
April	1st to 10th	Day	18% 9% 2 6% 5% 5% 4 3 5% 6% 36%	2400
	11th to 20th	Day	18% 8% 2 6% 4 5% 4 3 4 7% 39%	2374
	21st to end	Day	18% 6% 3 7% 5% 5% 5% 4 5% 6% 38%	2400
May	1st to 10th	Day	30% 7% 2 5% 4 4 4 3 5% 7% 28%	6013
	11th to 20th	Day	22% 9% 3 6% 4 4 5% 4 5% 6% 33%	6318
	21st to end	Day	21% 6% 2 5% 4 5% 5% 4 7% 8% 32%	6949
June	1st to 10th	Day	15% 6% 2 7% 6% 5% 5% 4 6% 9% 35%	2800
	11th to 20th	Day	17% 6% 3 6% 5% 5% 5% 5% 7% 8% 35%	2800
	21st to end	Day	13% 6% 3 8% 5% 5% 5% 4 6% 10% 37%	2800
July	1st to 10th	Day	11% 7% 3 8% 6% 5% 5% 5% 7% 10% 34%	6360
	11th to 20th	Day	11% 7% 3 7% 5% 5% 6% 5% 8% 11% 32%	6360
	21st to end	Day	13% 7% 2 7% 5% 4 5% 4 6% 8% 41%	6926
August	1st to 10th	Day	21% 6% 2 7% 5% 5% 5% 4 7% 8% 30%	4335
	11th to 20th	Day	14% 5% 2 6% 4 5% 5% 4 6% 9% 39%	3856
	21st to end	Day	14% 6% 2 5% 3 3 4 3 5% 10% 45%	4312
September	1st to 10th	Day	15% 6% 2 6% 4 4 4 4 5% 8% 43%	2400
	11th to 20th	Day	13% 5% 1 4 3 4 4 3 5% 7% 49%	2345
	21st to end	Day	18% 6% 2 6% 4 5% 4 4 5% 6% 38%	2200
October	1st to 10th	Day	20% 6% 2 6% 4 4 3 4 5% 6% 41%	2035
	11th to 20th	Day	15% 7% 2 6% 4 4 5% 4 5% 7% 42%	2000
	21st to end	Day	22% 6% 2 5% 4 4 4 4 5% 7% 38%	2067
November	1st to 10th	Day	13% 7% 2 5% 3 4 3 2 5% 6% 50%	1851
	11th to 20th	Day	18% 7% 2 5% 3 3 4 4 6% 6% 42%	1863
	21st to end	Day	17% 8% 2 6% 5% 4 5% 5% 5% 7% 38%	1650
December	1st to 10th	Day	16% 8% 2 7% 4 3 5% 4 6% 6% 37%	2600
	11th to 20th	Day	21% 9% 3 6% 4 3 3 3 5% 5% 39%	2986
	21st to end	Day	17% 10% 4 8% 5% 5% 4 3 5% 7% 30%	3960
January	1st to 10th	Night	13% 7% 3 10% 5% 5% 4 4 6% 7% 37%	6349
	11th to 20th	Night	12% 8% 4 11% 6% 5% 5% 4 5% 7% 36%	6315
	21st to end	Night	16% 9% 2 7% 4 4 4 4 6% 6% 38%	6600
February	1st to 10th	Night	16% 9% 3 6% 4 5% 4 4 4 7% 39%	2600
	11th to 20th	Night	16% 7% 3 6% 5% 4 5% 3 6% 6% 39%	2380
	21st to end	Night	17% 8% 2 7% 5% 4 4 3 5% 5% 39%	1980
March	1st to 10th	Night	19% 9% 3 5% 4 4 3 3 5% 6% 40%	5364
	11th to 20th	Night	14% 7% 3 5% 4 4 4 4 5% 7% 44%	5077
	21st to end	Night	16% 9% 3 7% 5% 3 4 3 5% 6% 38%	5064
April	1st to 10th	Night	18% 9% 3 8% 5% 5% 4 3 5% 6% 35%	2000
	11th to 20th	Night	19% 7% 2 6% 6% 4 5% 3 5% 6% 38%	1975
	21st to end	Night	18% 7% 2 6% 4 4 3 3 6% 6% 41%	2000
May	1st to 10th	Night	32% 8% 2 6% 3 3 4 3 5% 7% 28%	3968
	11th to 20th	Night	24% 10% 3 6% 4 3 3 3 5% 5% 34%	3575
	21st to end	Night	22% 6% 2 6% 5% 4 4 3 6% 8% 33%	3926
June	1st to 10th	Night	16% 6% 2 6% 4 5% 4 3 4 8% 42%	1600
	11th to 20th	Night	14% 7% 2 5% 4 5% 5% 4 6% 8% 41%	1600
	21st to end	Night	13% 4 2 6% 3 4 4 4 6% 10% 45%	1600
July	1st to 10th	Night	12% 6% 2 7% 5% 5% 5% 4 6% 9% 40%	3600
	11th to 20th	Night	14% 8% 3 6% 5% 5% 6% 4 6% 9% 35%	3600
	21st to end	Night	13% 5% 2 5% 4 4 5% 4 5% 8% 46%	3926
August	1st to 10th	Night	21% 6% 2 7% 4 4 4 4 6% 7% 34%	2810
	11th to 20th	Night	14% 7% 2 7% 4 5% 4 4 5% 6% 42%	3158
	21st to end	Night	12% 4 2 5% 3 4 4 3 5% 8% 50%	3586
September	1st to 10th	Night	16% 5% 2 5% 3 4 4 3 5% 7% 47%	2000
	11th to 20th	Night	13% 5% 2 5% 3 3 4 2 4 7% 52%	2055
	21st to end	Night	17% 6% 3 6% 3 3 4 3 4 7% 43%	2200
October	1st to 10th	Night	21% 6% 2 4 4 3 3 2 4 6% 44%	2360
	11th to 20th	Night	19% 5% 2 5% 3 3 3 3 4 6% 47%	2400
	21st to end	Night	22% 6% 2 4 3 2 3 3 5% 6% 43%	2771
November	1st to 10th	Night	13% 6% 2 5% 3 3 4 3 5% 7% 49%	2667
	11th to 20th	Night	18% 8% 3 5% 3 3 4 3 5% 6% 44%	2692
	21st to end	Night	14% 8% 2 6% 5% 4 4 4 5% 7% 42%	2745
December	1st to 10th	Night	14% 8% 3 7% 4 4 4 3 5% 7% 41%	4580
	11th to 20th	Night	24% 8% 2 5% 4 4 4 3 4 5% 38%	5208
	21st to end	Night	20% 11% 4 8% 5% 4 4 3 5% 5% 32%	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% 28% 7% 20% 10% 2	3598
	11th to 20th	Day	37% 29% 6% 16% 9% 3	3600
	21st to end	Day	35% 30% 8% 16% 11% 1	4355
February	1st to 10th	Day	20% 63% 6% 7% 4	1800
	11th to 20th	Day	17% 61% 3 10% 8% 1	1913
	21st to end	Day	17% 62% 4 10% 5% 1	1650
March	1st to 10th	Day	36% 30% 7% 13% 9% 7%	4479
	11th to 20th	Day	27% 32% 11% 22% 4 3	4878
	21st to end	Day	32% 30% 8% 6% 19% 5%	5868
April	1st to 10th	Day	22% 62% 3 7% 5% 1	2400
	11th to 20th	Day	17% 62% 4 8% 8%	2374
	21st to end	Day	19% 62% 3 9% 6% 1	2400
May	1st to 10th	Day	42% 31% 11% 10% 5%	6024
	11th to 20th	Day	39% 31% 7% 15% 8% 1	6322
	21st to end	Day	35% 32% 8% 16% 8% 1	6949
June	1st to 10th	Day	18% 63% 4 9% 6%	2800
	11th to 20th	Day	17% 63% 5% 9% 6%	2800
	21st to end	Day	17% 62% 4 9% 8%	2800
July	1st to 10th	Day	34% 31% 9% 16% 10% 1	6290
	11th to 20th	Day	33% 30% 12% 18% 7%	6285
	21st to end	Day	31% 27% 8% 18% 16% 1	6728
August	1st to 10th	Day	35% 38% 9% 13% 5%	4321
	11th to 20th	Day	24% 38% 11% 20% 6%	3892
	21st to end	Day	19% 37% 8% 26% 10% 1	4312
September	1st to 10th	Day	16% 59% 6% 12% 8%	2400
	11th to 20th	Day	17% 57% 4 10% 11% 2	2345
	21st to end	Day	21% 58% 5% 9% 6% 1	2200
October	1st to 10th	Day	24% 36% 4 13% 19% 4	3308
	11th to 20th	Day	18% 37% 5% 19% 18% 3	3240
	21st to end	Day	13% 36% 13% 20% 15% 3	3318
November	1st to 10th	Day	19% 54% 6% 12% 8% 1	1851
	11th to 20th	Day	16% 55% 4 12% 11% 2	1863
	21st to end	Day	18% 58% 6% 12% 4 1	1650
December	1st to 10th	Day	28% 38% 10% 18% 5% 1	2600
	11th to 20th	Day	32% 32% 9% 16% 9% 2	2986
	21st to end	Day	40% 29% 5% 14% 11% 1	3960
January	1st to 10th	Night	32% 29% 8% 17% 12% 2	6349
	11th to 20th	Night	33% 28% 13% 14% 10% 3	6360
	21st to end	Night	34% 29% 9% 11% 13% 4	6600
February	1st to 10th	Night	17% 62% 6% 10% 4 1	2600
	11th to 20th	Night	17% 61% 3 9% 8% 2	2382
	21st to end	Night	17% 62% 4 8% 7% 2	1980
March	1st to 10th	Night	33% 30% 9% 12% 11% 4	5374
	11th to 20th	Night	26% 31% 14% 18% 8% 3	5078
	21st to end	Night	35% 30% 5% 12% 17% 2	5064
April	1st to 10th	Night	20% 62% 3 9% 5% 1	2000
	11th to 20th	Night	17% 62% 5% 8% 8%	1975
	21st to end	Night	17% 61% 4 10% 7% 1	2000
May	1st to 10th	Night	42% 31% 10% 11% 5%	3974
	11th to 20th	Night	39% 32% 10% 11% 9%	3576
	21st to end	Night	37% 32% 9% 16% 6% 1	3927
June	1st to 10th	Night	15% 63% 3 9% 10%	1600
	11th to 20th	Night	15% 63% 6% 10% 5%	1600
	21st to end	Night	15% 60% 5% 12% 7% 1	1600
July	1st to 10th	Night	32% 30% 11% 14% 12% 1	3560
	11th to 20th	Night	35% 29% 11% 17% 8% 1	3552
	21st to end	Night	28% 27% 9% 22% 14% 1	3809
August	1st to 10th	Night	35% 39% 10% 11% 4 1	2800
	11th to 20th	Night	28% 38% 9% 21% 5%	3188
	21st to end	Night	18% 37% 7% 27% 10%	3586
September	1st to 10th	Night	15% 58% 6% 13% 9% 1	2000
	11th to 20th	Night	14% 57% 5% 10% 13% 2	2055
	21st to end	Night	21% 57% 4 10% 8% 1	2200
October	1st to 10th	Night	26% 36% 6% 17% 14% 1	3854
	11th to 20th	Night	14% 36% 6% 20% 21% 3	3899
	21st to end	Night	16% 36% 11% 22% 14% 1	4470
November	1st to 10th	Night	18% 54% 7% 11% 9% 1	2667
	11th to 20th	Night	16% 55% 5% 10% 12% 2	2692
	21st to end	Night	18% 57% 7% 13% 5% 1	2745
December	1st to 10th	Night	28% 36% 8% 24% 4	4580
	11th to 20th	Night	34% 32% 8% 13% 11% 2	5208
	21st to end	Night	40% 29% 7% 12% 10% 2	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	36% 24% 28% 11% 2	200
	11th to 20th	Day	39% 27% 26% 7% 2	200
	21st to end	Day	28% 32% 28% 7% 4 1	307
February	1st to 10th	Day	34% 28% 29% 8% 1	300
	11th to 20th	Day	37% 28% 28% 7% 1	452
	21st to end	Day	30% 26% 33% 9% 2	414
March	1st to 10th	Day	29% 27% 27% 13% 3	500
	11th to 20th	Day	27% 26% 30% 13% 4 1	500
	21st to end	Day	32% 23% 30% 9% 4 1	550
April	1st to 10th	Day	35% 23% 26% 12% 4 1	500
	11th to 20th	Day	29% 24% 29% 10% 6% 1	492
	21st to end	Day	30% 17% 34% 14% 4 2	500
May	1st to 10th	Day	36% 19% 23% 14% 6% 2	503
	11th to 20th	Day	23% 20% 31% 17% 7% 2	527
	21st to end	Day	23% 10% 30% 24% 12% 2	573
June	1st to 10th	Day	20% 13% 33% 21% 11% 1	530
	11th to 20th	Day	22% 15% 25% 25% 12% 1	530
	21st to end	Day	15% 14% 35% 26% 10% 1	530
July	1st to 10th	Day	14% 10% 30% 28% 15% 4	525
	11th to 20th	Day	10% 9% 28% 31% 19% 2	524
	21st to end	Day	14% 9% 35% 27% 13% 2	576
August	1st to 10th	Day	13% 8% 27% 30% 15% 6%	526
	11th to 20th	Day	15% 8% 25% 30% 17% 5%	519
	21st to end	Day	13% 11% 30% 26% 14% 7%	583
September	1st to 10th	Day	18% 12% 26% 22% 14% 7%	530
	11th to 20th	Day	14% 9% 26% 23% 17% 11%	530
	21st to end	Day	24% 11% 26% 23% 11% 5%	530
October	1st to 10th	Day	25% 12% 23% 22% 13% 5%	530
	11th to 20th	Day	22% 17% 30% 19% 10% 2	530
	21st to end	Day	26% 19% 30% 18% 7% 1	509
November	1st to 10th	Day	21% 19% 28% 24% 7% 2	425
	11th to 20th	Day	28% 23% 25% 18% 5%	421
	21st to end	Day	32% 22% 31% 13% 3	250
December	1st to 10th	Day	32% 27% 27% 11% 4 1	200
	11th to 20th	Day	40% 23% 26% 9% 3	200
	21st to end	Day	29% 23% 30% 12% 5%	220
January	1st to 10th	Night	22% 25% 36% 14% 2	800
	11th to 20th	Night	27% 22% 28% 21% 3	800
	21st to end	Night	21% 23% 36% 17% 2	880
February	1st to 10th	Night	24% 20% 37% 18% 2	800
	11th to 20th	Night	28% 25% 33% 13% 1	783
	21st to end	Night	29% 23% 31% 14% 3	660
March	1st to 10th	Night	26% 23% 33% 16% 3	800
	11th to 20th	Night	25% 23% 29% 19% 3 1	800
	21st to end	Night	23% 22% 35% 16% 4	880
April	1st to 10th	Night	26% 21% 33% 16% 4	800
	11th to 20th	Night	23% 20% 32% 20% 5%	791
	21st to end	Night	23% 18% 28% 24% 6%	800
May	1st to 10th	Night	29% 14% 28% 24% 5%	566
	11th to 20th	Night	22% 12% 33% 25% 7%	394
	21st to end	Night	16% 8% 28% 36% 12%	433
June	1st to 10th	Night	18% 6% 27% 38% 12% 1	400
	11th to 20th	Night	15% 7% 30% 35% 14%	400
	21st to end	Night	13% 5% 28% 43% 12%	400
July	1st to 10th	Night	12% 6% 20% 42% 19% 1	390
	11th to 20th	Night	12% 5% 23% 43% 17% 1	388
	21st to end	Night	12% 4 24% 42% 16% 1	438
August	1st to 10th	Night	11% 3 22% 41% 21% 1	531
	11th to 20th	Night	13% 4 22% 36% 23% 2	763
	21st to end	Night	15% 6% 23% 35% 21% 1	880
September	1st to 10th	Night	17% 7% 25% 32% 17% 2	800
	11th to 20th	Night	15% 8% 22% 32% 20% 4	800
	21st to end	Night	19% 8% 24% 31% 17% 2	800
October	1st to 10th	Night	22% 10% 24% 27% 15% 1	800
	11th to 20th	Night	20% 14% 29% 30% 8%	800
	21st to end	Night	24% 15% 32% 22% 7%	880
November	1st to 10th	Night	18% 17% 32% 24% 8% 1	820
	11th to 20th	Night	25% 18% 28% 21% 7% 1	829
	21st to end	Night	22% 20% 33% 20% 6% 1	800
December	1st to 10th	Night	25% 20% 30% 19% 5%	800
	11th to 20th	Night	26% 22% 29% 20% 3	800
	21st to end	Night	27% 20% 32% 18% 3	880

Page generated at 2025-11-15 00:55:57. Version ac07

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