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 2024-01-12.

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	16% 7% 3 5% 6% 3 5% 5% 5% 7% 38%	74747
	Night	17% 7% 3 5% 5% 3 4 4 5% 7% 41%	74964
Transparency	Day	30% 38% 8% 14% 9% 1	74452
	Night	28% 38% 9% 15% 9% 1	74793
Seeing	Day	24% 17% 29% 19% 9% 3	13774
	Night	21% 16% 29% 24% 8% 1	23065

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	13% 7% 3 6% 5% 3 5% 6% 6% 5% 40%	1517
	11th to 20th	Day	15% 9% 4 7% 6% 4 5% 5% 6% 6% 34%	1454
	21st to end	Day	13% 8% 4 5% 5% 3 5% 5% 6% 7% 39%	1741
February	1st to 10th	Day	17% 7% 4 7% 6% 4 5% 5% 5% 6% 32%	1620
	11th to 20th	Day	14% 8% 3 6% 6% 4 5% 5% 5% 7% 39%	1708
	21st to end	Day	19% 9% 3 7% 5% 3 4 3 5% 6% 35%	1480
March	1st to 10th	Day	13% 7% 3 7% 6% 4 4 3 5% 7% 40%	1797
	11th to 20th	Day	15% 8% 4 6% 7% 3 5% 5% 6% 7% 36%	1934
	21st to end	Day	19% 9% 3 5% 5% 3 4 4 4 6% 38%	2330
April	1st to 10th	Day	17% 8% 3 5% 6% 3 5% 4 5% 6% 38%	2160
	11th to 20th	Day	18% 6% 2 5% 5% 3 5% 4 4 7% 41%	2134
	21st to end	Day	19% 6% 3 6% 6% 3 6% 4 5% 6% 37%	2160
May	1st to 10th	Day	24% 7% 3 5% 6% 3 4 4 5% 6% 34%	2383
	11th to 20th	Day	20% 6% 3 5% 5% 3 6% 6% 5% 7% 36%	2478
	21st to end	Day	15% 5% 3 4 6% 3 5% 4 7% 8% 39%	2725
June	1st to 10th	Day	16% 5% 3 5% 7% 4 5% 5% 6% 9% 36%	2520
	11th to 20th	Day	16% 6% 3 6% 5% 4 5% 6% 7% 8% 34%	2520
	21st to end	Day	13% 5% 3 6% 7% 3 5% 5% 5% 10% 38%	2520
July	1st to 10th	Day	12% 6% 2 6% 7% 4 5% 5% 7% 9% 36%	2520
	11th to 20th	Day	11% 5% 2 5% 5% 4 6% 6% 7% 10% 39%	2520
	21st to end	Day	11% 6% 3 5% 7% 3 6% 6% 6% 9% 38%	2744
August	1st to 10th	Day	11% 6% 3 5% 7% 4 5% 6% 9% 9% 35%	2383
	11th to 20th	Day	12% 6% 2 6% 6% 5% 7% 6% 6% 8% 36%	2132
	21st to end	Day	14% 6% 3 5% 5% 3 4 5% 5% 8% 41%	2376
September	1st to 10th	Day	15% 6% 3 6% 4 3 5% 4 5% 8% 41%	2160
	11th to 20th	Day	15% 5% 1 4 4 3 5% 4 4 7% 49%	2111
	21st to end	Day	17% 6% 2 5% 4 3 4 5% 5% 7% 41%	1980
October	1st to 10th	Day	22% 5% 3 5% 5% 3 3 4 5% 7% 39%	1832
	11th to 20th	Day	15% 7% 2 4 5% 3 5% 5% 5% 7% 41%	1800
	21st to end	Day	24% 6% 2 4 5% 3 4 6% 5% 7% 35%	1861
November	1st to 10th	Day	14% 7% 3 4 4 3 3 3 4 6% 50%	1671
	11th to 20th	Day	19% 6% 2 4 4 2 4 4 5% 6% 43%	1710
	21st to end	Day	17% 7% 3 5% 5% 3 4 7% 5% 7% 39%	1568
December	1st to 10th	Day	18% 9% 3 6% 6% 3 4 5% 5% 8% 33%	1520
	11th to 20th	Day	21% 7% 3 6% 4 3 4 4 6% 6% 37%	1906
	21st to end	Day	18% 12% 5% 9% 7% 4 5% 4 4 6% 25%	2772
January	1st to 10th	Night	14% 7% 3 5% 4 3 4 4 6% 8% 42%	2649
	11th to 20th	Night	17% 7% 3 5% 6% 3 5% 5% 4 7% 36%	2546
	21st to end	Night	12% 8% 3 6% 4 3 4 5% 6% 7% 41%	2614
February	1st to 10th	Night	17% 8% 3 5% 4 3 5% 4 4 8% 38%	2340
	11th to 20th	Night	16% 6% 3 5% 5% 3 6% 4 5% 7% 38%	2136
	21st to end	Night	18% 8% 2 6% 6% 3 4 4 4 5% 39%	1776
March	1st to 10th	Night	15% 8% 3 5% 4 2 4 3 4 7% 44%	2150
	11th to 20th	Night	17% 7% 3 4 5% 2 5% 5% 4 7% 42%	2021
	21st to end	Night	16% 6% 3 6% 5% 3 4 4 6% 8% 39%	2026
April	1st to 10th	Night	17% 8% 3 7% 5% 3 5% 4 5% 7% 36%	1800
	11th to 20th	Night	18% 6% 3 5% 6% 3 5% 4 5% 7% 39%	1775
	21st to end	Night	20% 7% 3 5% 5% 3 4 3 6% 6% 40%	1800
May	1st to 10th	Night	23% 8% 4 6% 4 2 5% 5% 4 5% 34%	1590
	11th to 20th	Night	18% 6% 2 5% 5% 3 5% 4 6% 7% 39%	1415
	21st to end	Night	14% 5% 2 5% 5% 3 5% 5% 5% 9% 42%	1550
June	1st to 10th	Night	17% 5% 2 5% 5% 3 5% 4 4 8% 42%	1440
	11th to 20th	Night	14% 6% 2 4 4 3 5% 6% 5% 8% 41%	1440
	21st to end	Night	12% 4 2 5% 4 2 4 5% 5% 10% 46%	1440
July	1st to 10th	Night	13% 4 3 5% 5% 3 5% 4 5% 9% 43%	1440
	11th to 20th	Night	11% 5% 2 4 5% 4 5% 6% 7% 10% 42%	1440
	21st to end	Night	12% 4 2 3 5% 3 5% 7% 6% 9% 44%	1574
August	1st to 10th	Night	10% 5% 3 6% 5% 2 4 6% 6% 9% 44%	1551
	11th to 20th	Night	12% 7% 3 6% 6% 4 6% 6% 5% 7% 39%	1749
	21st to end	Night	15% 4 2 5% 5% 4 5% 5% 5% 8% 43%	1980
September	1st to 10th	Night	16% 5% 2 4 4 3 4 4 5% 8% 45%	1800
	11th to 20th	Night	14% 5% 2 4 3 2 4 3 3 7% 52%	1849
	21st to end	Night	16% 5% 3 4 5% 2 4 4 4 7% 46%	1980
October	1st to 10th	Night	23% 5% 3 3 4 3 3 3 4 6% 42%	2124
	11th to 20th	Night	19% 5% 2 5% 4 3 3 4 4 7% 46%	2160
	21st to end	Night	23% 7% 2 4 3 2 3 4 5% 6% 41%	2493
November	1st to 10th	Night	14% 6% 2 5% 4 2 4 4 5% 6% 49%	2407
	11th to 20th	Night	19% 6% 3 4 3 2 4 3 5% 6% 44%	2470
	21st to end	Night	14% 7% 2 5% 5% 3 4 5% 5% 7% 43%	2607
December	1st to 10th	Night	19% 7% 3 5% 6% 3 5% 4 6% 7% 35%	2660
	11th to 20th	Night	19% 8% 2 5% 5% 3 6% 5% 5% 6% 36%	3288
	21st to end	Night	22% 10% 4 6% 5% 3 4 3 5% 6% 32%	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	26% 42% 8% 18% 5%	1518
	11th to 20th	Day	32% 42% 10% 9% 5% 2	1454
	21st to end	Day	28% 38% 8% 16% 8% 1	1741
February	1st to 10th	Day	33% 37% 7% 13% 10% 1	1620
	11th to 20th	Day	31% 39% 7% 13% 9% 1	1717
	21st to end	Day	34% 37% 7% 13% 7% 2	1480
March	1st to 10th	Day	28% 37% 9% 17% 9% 1	1800
	11th to 20th	Day	31% 37% 8% 14% 9% 1	1934
	21st to end	Day	32% 37% 5% 13% 11% 2	2330
April	1st to 10th	Day	29% 37% 7% 15% 9% 3	2160
	11th to 20th	Day	31% 37% 8% 13% 8% 3	2134
	21st to end	Day	30% 37% 7% 12% 10% 3	2160
May	1st to 10th	Day	32% 37% 6% 12% 10% 2	2383
	11th to 20th	Day	31% 39% 6% 12% 10% 2	2482
	21st to end	Day	26% 40% 10% 14% 9% 2	2725
June	1st to 10th	Day	28% 40% 10% 13% 8% 1	2520
	11th to 20th	Day	30% 40% 10% 14% 4 1	2520
	21st to end	Day	29% 39% 10% 16% 6%	2520
July	1st to 10th	Day	30% 40% 8% 14% 8% 1	2450
	11th to 20th	Day	24% 40% 12% 16% 8% 1	2445
	21st to end	Day	26% 42% 8% 12% 10% 2	2591
August	1st to 10th	Day	28% 40% 10% 14% 8%	2369
	11th to 20th	Day	29% 39% 9% 15% 8% 1	2132
	21st to end	Day	31% 38% 7% 13% 9% 2	2376
September	1st to 10th	Day	28% 38% 8% 13% 11% 2	2160
	11th to 20th	Day	23% 37% 8% 15% 16% 2	2111
	21st to end	Day	30% 37% 6% 12% 13% 2	1980
October	1st to 10th	Day	29% 38% 8% 15% 11%	1832
	11th to 20th	Day	27% 38% 9% 16% 9% 1	1800
	21st to end	Day	32% 39% 7% 12% 8% 2	1861
November	1st to 10th	Day	20% 41% 8% 16% 13% 2	1671
	11th to 20th	Day	28% 40% 8% 14% 8% 2	1710
	21st to end	Day	28% 42% 8% 15% 6% 1	1568
December	1st to 10th	Day	30% 41% 11% 12% 6% 1	1520
	11th to 20th	Day	33% 35% 12% 15% 6% 1	1906
	21st to end	Day	46% 29% 8% 12% 5%	2772
January	1st to 10th	Night	26% 41% 10% 15% 8%	2649
	11th to 20th	Night	30% 43% 9% 13% 4 1	2546
	21st to end	Night	26% 39% 8% 17% 10% 1	2614
February	1st to 10th	Night	31% 37% 9% 13% 9% 1	2340
	11th to 20th	Night	30% 39% 9% 12% 8% 2	2138
	21st to end	Night	32% 37% 6% 16% 9% 2	1776
March	1st to 10th	Night	26% 37% 11% 17% 8% 1	2160
	11th to 20th	Night	31% 37% 8% 15% 7% 1	2022
	21st to end	Night	26% 38% 8% 14% 12% 2	2026
April	1st to 10th	Night	31% 38% 8% 12% 9% 2	1800
	11th to 20th	Night	33% 38% 6% 13% 11% 1	1775
	21st to end	Night	28% 38% 8% 13% 10% 3	1800
May	1st to 10th	Night	33% 38% 6% 11% 11% 2	1590
	11th to 20th	Night	28% 37% 8% 12% 12% 2	1416
	21st to end	Night	23% 40% 11% 15% 8% 2	1551
June	1st to 10th	Night	28% 38% 8% 16% 10%	1440
	11th to 20th	Night	27% 39% 10% 18% 5% 1	1440
	21st to end	Night	22% 41% 12% 18% 8%	1440
July	1st to 10th	Night	27% 40% 10% 14% 8% 2	1400
	11th to 20th	Night	24% 43% 9% 15% 8% 1	1392
	21st to end	Night	20% 42% 12% 14% 11% 1	1486
August	1st to 10th	Night	24% 39% 12% 15% 10%	1541
	11th to 20th	Night	29% 38% 11% 14% 8%	1749
	21st to end	Night	29% 39% 8% 12% 11% 1	1980
September	1st to 10th	Night	26% 38% 9% 15% 11% 1	1800
	11th to 20th	Night	24% 36% 6% 18% 16% 1	1849
	21st to end	Night	25% 38% 7% 15% 15% 1	1980
October	1st to 10th	Night	29% 37% 7% 15% 11%	2124
	11th to 20th	Night	28% 38% 9% 16% 8%	2160
	21st to end	Night	29% 38% 9% 15% 8% 1	2493
November	1st to 10th	Night	20% 41% 9% 14% 13% 2	2407
	11th to 20th	Night	27% 40% 7% 14% 10% 2	2470
	21st to end	Night	25% 41% 10% 17% 7%	2607
December	1st to 10th	Night	28% 41% 9% 14% 7% 1	2660
	11th to 20th	Night	31% 35% 11% 12% 10% 1	3288
	21st to end	Night	40% 29% 11% 15% 5%	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	34% 23% 29% 12% 2	180
	11th to 20th	Day	35% 27% 28% 8% 2	164
	21st to end	Day	27% 32% 29% 6% 4 1	246
February	1st to 10th	Day	37% 28% 26% 8% 1	240
	11th to 20th	Day	34% 28% 29% 7% 1	376
	21st to end	Day	33% 26% 31% 9% 2	346
March	1st to 10th	Day	26% 27% 29% 14% 4	420
	11th to 20th	Day	27% 27% 30% 13% 3 1	420
	21st to end	Day	32% 23% 30% 9% 5% 2	462
April	1st to 10th	Day	32% 22% 26% 14% 5% 1	420
	11th to 20th	Day	27% 22% 30% 12% 7% 2	412
	21st to end	Day	32% 18% 31% 13% 4 2	420
May	1st to 10th	Day	35% 20% 23% 13% 6% 2	423
	11th to 20th	Day	23% 20% 32% 17% 7% 1	447
	21st to end	Day	20% 9% 29% 25% 13% 3	485
June	1st to 10th	Day	19% 14% 33% 22% 11% 1	450
	11th to 20th	Day	21% 16% 26% 24% 12% 1	450
	21st to end	Day	14% 14% 34% 26% 11% 1	450
July	1st to 10th	Day	14% 10% 29% 26% 16% 5%	445
	11th to 20th	Day	11% 8% 28% 32% 19% 2	444
	21st to end	Day	14% 9% 36% 26% 13% 2	488
August	1st to 10th	Day	11% 9% 28% 32% 14% 7%	446
	11th to 20th	Day	15% 7% 27% 29% 16% 6%	439
	21st to end	Day	13% 12% 29% 25% 14% 7%	495
September	1st to 10th	Day	19% 11% 26% 22% 14% 7%	450
	11th to 20th	Day	16% 10% 29% 20% 14% 10%	450
	21st to end	Day	22% 12% 28% 22% 12% 5%	450
October	1st to 10th	Day	28% 12% 24% 20% 12% 4	450
	11th to 20th	Day	20% 17% 30% 21% 10% 2	450
	21st to end	Day	29% 18% 30% 17% 6% 1	435
November	1st to 10th	Day	21% 18% 25% 26% 7% 2	365
	11th to 20th	Day	29% 22% 25% 17% 6% 1	370
	21st to end	Day	29% 21% 32% 14% 3	228
December	1st to 10th	Day	32% 28% 26% 10% 4 1	180
	11th to 20th	Day	39% 22% 28% 8% 3	180
	21st to end	Day	30% 25% 30% 12% 4	198
January	1st to 10th	Night	22% 24% 37% 15% 3	760
	11th to 20th	Night	26% 21% 29% 21% 3	728
	21st to end	Night	21% 23% 36% 18% 2	792
February	1st to 10th	Night	26% 20% 35% 17% 2	720
	11th to 20th	Night	26% 26% 33% 14% 1	703
	21st to end	Night	30% 23% 31% 14% 2	592
March	1st to 10th	Night	25% 23% 33% 16% 3	720
	11th to 20th	Night	26% 23% 29% 18% 3 1	720
	21st to end	Night	22% 22% 34% 17% 5% 1	792
April	1st to 10th	Night	24% 22% 33% 16% 4	720
	11th to 20th	Night	22% 19% 33% 21% 5%	711
	21st to end	Night	24% 19% 26% 25% 6%	720
May	1st to 10th	Night	28% 14% 28% 24% 6%	510
	11th to 20th	Night	21% 12% 36% 24% 7%	354
	21st to end	Night	15% 9% 26% 38% 13%	389
June	1st to 10th	Night	18% 5% 27% 37% 12% 1	360
	11th to 20th	Night	15% 7% 30% 35% 13%	360
	21st to end	Night	12% 4 27% 46% 11%	360
July	1st to 10th	Night	13% 6% 20% 41% 20% 1	350
	11th to 20th	Night	12% 5% 23% 42% 17% 1	348
	21st to end	Night	12% 4 25% 41% 16% 1	394
August	1st to 10th	Night	10% 3 24% 40% 22% 1	477
	11th to 20th	Night	14% 4 22% 34% 24% 2	685
	21st to end	Night	15% 6% 21% 35% 21% 2	792
September	1st to 10th	Night	18% 7% 25% 32% 16% 3	720
	11th to 20th	Night	16% 8% 24% 30% 18% 4	720
	21st to end	Night	18% 8% 25% 30% 17% 2	720
October	1st to 10th	Night	24% 10% 23% 27% 14% 1	720
	11th to 20th	Night	20% 13% 30% 30% 7%	720
	21st to end	Night	26% 15% 32% 21% 6%	792
November	1st to 10th	Night	17% 17% 32% 24% 9% 1	740
	11th to 20th	Night	25% 18% 28% 22% 7% 1	760
	21st to end	Night	20% 19% 33% 21% 6% 1	760
December	1st to 10th	Night	25% 21% 29% 18% 5%	760
	11th to 20th	Night	25% 23% 29% 21% 3	760
	21st to end	Night	27% 20% 33% 17% 2	836

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