Newberry Star Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Newberry Star 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	8% 5% 2 6% 5% 5% 5% 5% 7% 10% 41%	126744
	Night	9% 6% 2 6% 4 4 5% 4 6% 9% 44%	123633
Transparency	Day	36% 9% 15% 19% 15% 6%	130493
	Night	35% 8% 15% 19% 16% 7%	127953
Seeing	Day	10% 7% 20% 25% 23% 16%	16748
	Night	10% 5% 21% 33% 24% 6%	26755

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% 6% 2 5% 2 3 3 2 4 7% 56%	4056
	11th to 20th	Day	19% 9% 4 8% 4 3 3 3 4 6% 37%	4060
	21st to end	Day	10% 5% 2 5% 3 3 3 3 6% 9% 49%	4717
February	1st to 10th	Day	14% 7% 2 6% 5% 4 3 3 5% 6% 45%	2000
	11th to 20th	Day	12% 5% 2 5% 4 4 3 4 5% 6% 50%	1948
	21st to end	Day	11% 6% 2 6% 4 4 4 3 6% 6% 49%	1665
March	1st to 10th	Day	13% 7% 2 6% 4 4 5% 4 6% 8% 41%	4935
	11th to 20th	Day	8% 3 2 4 3 3 4 3 6% 9% 56%	4980
	21st to end	Day	10% 5% 2 4 4 3 4 4 6% 9% 50%	5465
April	1st to 10th	Day	7% 4 1 5% 5% 4 5% 4 7% 9% 50%	2200
	11th to 20th	Day	9% 5% 2 7% 4 5% 3 4 5% 7% 48%	2176
	21st to end	Day	4 3 1 4 5% 5% 5% 5% 7% 8% 53%	2515
May	1st to 10th	Day	5% 4 2 5% 5% 5% 5% 5% 8% 10% 47%	5862
	11th to 20th	Day	10% 6% 2 6% 4 4 4 4 7% 9% 45%	5861
	21st to end	Day	4 4 1 5% 4 5% 5% 5% 7% 12% 49%	6433
June	1st to 10th	Day	9% 7% 3 8% 5% 7% 8% 6% 8% 11% 29%	2600
	11th to 20th	Day	4 5% 2 8% 8% 7% 9% 7% 10% 12% 28%	2600
	21st to end	Day	7% 6% 3 9% 7% 6% 8% 7% 9% 10% 29%	2600
July	1st to 10th	Day	6% 6% 3 10% 7% 8% 9% 7% 11% 14% 18%	5900
	11th to 20th	Day	4 4 2 6% 6% 7% 8% 7% 10% 16% 30%	5900
	21st to end	Day	5% 4 2 7% 6% 7% 8% 6% 10% 14% 31%	6424
August	1st to 10th	Day	10% 5% 2 7% 5% 7% 8% 7% 9% 13% 27%	4234
	11th to 20th	Day	6% 5% 2 8% 6% 7% 8% 6% 8% 12% 31%	3922
	21st to end	Day	9% 6% 2 8% 6% 7% 7% 6% 9% 11% 29%	4021
September	1st to 10th	Day	9% 7% 3 11% 7% 8% 8% 6% 8% 11% 22%	2200
	11th to 20th	Day	11% 8% 3 9% 6% 8% 7% 5% 8% 8% 27%	2200
	21st to end	Day	8% 7% 3 8% 6% 6% 6% 4 6% 9% 37%	2200
October	1st to 10th	Day	10% 6% 3 9% 5% 5% 5% 5% 6% 8% 38%	2200
	11th to 20th	Day	6% 4 2 5% 4 3 4 3 4 8% 57%	2034
	21st to end	Day	7% 5% 2 5% 4 4 5% 4 6% 8% 52%	2200
November	1st to 10th	Day	8% 4 2 6% 4 4 4 5% 5% 7% 51%	2057
	11th to 20th	Day	8% 6% 2 5% 5% 4 4 4 5% 7% 50%	2010
	21st to end	Day	11% 6% 2 6% 5% 3 4 3 5% 7% 49%	1800
December	1st to 10th	Day	5% 4 1 4 4 4 4 4 5% 7% 57%	2930
	11th to 20th	Day	10% 7% 2 6% 4 4 4 4 6% 7% 46%	3373
	21st to end	Day	14% 8% 2 7% 4 4 4 3 5% 6% 43%	4466
January	1st to 10th	Night	9% 6% 2 4 2 2 3 2 4 7% 57%	5889
	11th to 20th	Night	18% 8% 3 7% 5% 4 5% 4 6% 7% 33%	5900
	21st to end	Night	14% 7% 3 6% 4 4 4 4 6% 8% 42%	6235
February	1st to 10th	Night	12% 6% 2 6% 4 5% 4 3 4 6% 47%	2400
	11th to 20th	Night	11% 7% 3 6% 4 4 3 3 5% 6% 48%	2338
	21st to end	Night	11% 6% 3 6% 4 3 3 3 5% 5% 50%	1963
March	1st to 10th	Night	15% 8% 3 7% 4 4 4 3 5% 6% 42%	4918
	11th to 20th	Night	6% 5% 2 4 4 4 4 3 6% 9% 55%	4980
	21st to end	Night	10% 5% 2 5% 4 4 4 4 6% 7% 50%	5467
April	1st to 10th	Night	8% 6% 2 5% 4 4 4 3 6% 8% 51%	2200
	11th to 20th	Night	6% 5% 2 6% 4 4 3 3 6% 8% 52%	2173
	21st to end	Night	5% 3 1 5% 4 3 4 3 6% 8% 57%	1897
May	1st to 10th	Night	5% 4 2 5% 4 4 5% 5% 7% 9% 51%	4033
	11th to 20th	Night	9% 6% 2 6% 4 3 4 4 6% 10% 48%	4032
	21st to end	Night	3 3 1 4 3 4 4 4 7% 11% 58%	4421
June	1st to 10th	Night	9% 6% 3 7% 5% 5% 6% 5% 9% 11% 36%	1800
	11th to 20th	Night	5% 4 2 6% 5% 6% 6% 7% 9% 15% 35%	1800
	21st to end	Night	5% 5% 2 6% 5% 5% 6% 6% 9% 13% 38%	1800
July	1st to 10th	Night	8% 6% 3 9% 7% 8% 8% 7% 9% 13% 20%	4058
	11th to 20th	Night	3 4 2 7% 5% 6% 7% 6% 9% 14% 36%	4057
	21st to end	Night	5% 6% 3 8% 7% 7% 8% 7% 9% 11% 28%	4427
August	1st to 10th	Night	8% 6% 2 8% 5% 6% 6% 6% 10% 13% 30%	2915
	11th to 20th	Night	4 3 2 5% 4 4 6% 6% 9% 14% 44%	3121
	21st to end	Night	7% 6% 3 9% 6% 6% 7% 5% 9% 11% 31%	3841
September	1st to 10th	Night	7% 8% 3 10% 5% 5% 7% 6% 9% 11% 29%	2200
	11th to 20th	Night	11% 7% 3 9% 6% 5% 6% 5% 9% 9% 30%	2200
	21st to end	Night	9% 6% 3 6% 5% 5% 5% 5% 6% 9% 41%	2200
October	1st to 10th	Night	11% 6% 2 6% 5% 4 5% 4 6% 8% 43%	2200
	11th to 20th	Night	6% 4 2 5% 3 3 3 3 5% 7% 58%	2365
	21st to end	Night	7% 6% 2 6% 4 4 4 4 5% 7% 52%	2640
November	1st to 10th	Night	7% 4 2 5% 4 4 4 4 6% 7% 53%	2461
	11th to 20th	Night	9% 6% 2 5% 4 4 3 4 5% 6% 52%	2540
	21st to end	Night	9% 7% 2 5% 4 4 5% 4 5% 7% 48%	2600
December	1st to 10th	Night	9% 5% 2 5% 3 3 3 3 5% 7% 55%	4250
	11th to 20th	Night	11% 7% 2 5% 5% 3 4 3 4 7% 48%	4822
	21st to end	Night	13% 8% 3 7% 5% 4 4 4 5% 7% 41%	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	29% 4 7% 16% 28% 17%	4057
	11th to 20th	Day	49% 4 4 12% 19% 12%	4060
	21st to end	Day	32% 4 11% 24% 17% 11%	4717
February	1st to 10th	Day	40% 6% 8% 14% 21% 12%	2000
	11th to 20th	Day	34% 5% 9% 16% 23% 11%	1958
	21st to end	Day	35% 5% 10% 17% 20% 13%	1665
March	1st to 10th	Day	38% 7% 9% 15% 19% 11%	4935
	11th to 20th	Day	25% 5% 11% 18% 23% 18%	4980
	21st to end	Day	31% 5% 10% 25% 19% 10%	5465
April	1st to 10th	Day	29% 8% 12% 20% 20% 12%	2200
	11th to 20th	Day	35% 6% 9% 18% 23% 9%	2176
	21st to end	Day	26% 7% 13% 23% 22% 9%	2515
May	1st to 10th	Day	29% 9% 20% 26% 13% 4	5897
	11th to 20th	Day	34% 8% 14% 31% 11% 2	5865
	21st to end	Day	26% 9% 17% 31% 15% 2	6447
June	1st to 10th	Day	45% 12% 17% 18% 7% 1	2600
	11th to 20th	Day	41% 16% 20% 19% 4	2600
	21st to end	Day	44% 14% 22% 15% 5%	2600
July	1st to 10th	Day	48% 18% 27% 6%	5835
	11th to 20th	Day	35% 15% 37% 12% 1	5831
	21st to end	Day	37% 15% 28% 18% 2	6240
August	1st to 10th	Day	43% 15% 26% 13% 3	4221
	11th to 20th	Day	39% 15% 21% 17% 8%	3960
	21st to end	Day	43% 15% 20% 19% 3	4021
September	1st to 10th	Day	50% 15% 18% 10% 6% 1	2200
	11th to 20th	Day	49% 13% 16% 14% 8% 1	2200
	21st to end	Day	43% 7% 14% 18% 14% 4	2200
October	1st to 10th	Day	51% 8% 9% 13% 13% 6%	3590
	11th to 20th	Day	20% 4 6% 17% 39% 14%	3287
	21st to end	Day	21% 5% 7% 23% 34% 9%	3538
November	1st to 10th	Day	31% 6% 11% 20% 19% 14%	2057
	11th to 20th	Day	34% 5% 8% 17% 23% 12%	2010
	21st to end	Day	36% 4 9% 19% 24% 8%	1800
December	1st to 10th	Day	27% 5% 12% 22% 22% 12%	2930
	11th to 20th	Day	36% 6% 9% 23% 18% 8%	3370
	21st to end	Day	41% 4 9% 19% 21% 5%	4466
January	1st to 10th	Night	28% 4 7% 15% 32% 15%	5889
	11th to 20th	Night	49% 5% 6% 16% 18% 6%	5900
	21st to end	Night	40% 6% 10% 18% 17% 10%	6235
February	1st to 10th	Night	38% 5% 9% 16% 21% 12%	2400
	11th to 20th	Night	37% 5% 8% 19% 19% 12%	2339
	21st to end	Night	35% 5% 11% 17% 21% 11%	1963
March	1st to 10th	Night	43% 6% 8% 15% 17% 10%	4918
	11th to 20th	Night	26% 6% 13% 17% 20% 18%	4980
	21st to end	Night	32% 6% 10% 22% 19% 11%	5467
April	1st to 10th	Night	31% 6% 13% 20% 19% 10%	2200
	11th to 20th	Night	30% 7% 9% 23% 21% 10%	2173
	21st to end	Night	23% 7% 14% 28% 19% 8%	1897
May	1st to 10th	Night	26% 10% 20% 28% 12% 4	4060
	11th to 20th	Night	31% 8% 15% 28% 15% 2	4033
	21st to end	Night	20% 7% 19% 35% 18% 1	4429
June	1st to 10th	Night	38% 12% 22% 22% 7%	1800
	11th to 20th	Night	33% 16% 26% 21% 4	1800
	21st to end	Night	34% 16% 25% 20% 5% 1	1800
July	1st to 10th	Night	51% 18% 25% 5% 1	4015
	11th to 20th	Night	35% 16% 37% 11% 1	4006
	21st to end	Night	43% 15% 23% 17% 1	4297
August	1st to 10th	Night	40% 14% 32% 11% 3	2904
	11th to 20th	Night	26% 14% 30% 22% 7%	3149
	21st to end	Night	42% 14% 23% 17% 3	3841
September	1st to 10th	Night	43% 17% 21% 13% 5% 1	2200
	11th to 20th	Night	46% 13% 18% 16% 7% 1	2200
	21st to end	Night	38% 10% 18% 18% 13% 4	2200
October	1st to 10th	Night	50% 9% 12% 12% 11% 7%	3590
	11th to 20th	Night	21% 5% 7% 20% 34% 12%	3851
	21st to end	Night	23% 4 6% 22% 35% 10%	4252
November	1st to 10th	Night	28% 7% 11% 21% 19% 13%	2461
	11th to 20th	Night	32% 5% 9% 19% 21% 13%	2540
	21st to end	Night	35% 5% 11% 18% 21% 10%	2600
December	1st to 10th	Night	30% 4 11% 21% 18% 16%	4250
	11th to 20th	Night	37% 6% 10% 21% 17% 10%	4824
	21st to end	Night	43% 5% 10% 19% 18% 6%	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	9% 14% 50% 19% 8% 1	300
	11th to 20th	Day	11% 15% 39% 24% 9% 2	300
	21st to end	Day	16% 20% 42% 18% 4	330
February	1st to 10th	Day	15% 12% 34% 29% 9% 1	300
	11th to 20th	Day	16% 14% 36% 25% 7% 2	300
	21st to end	Day	9% 14% 38% 26% 12% 1	264
March	1st to 10th	Day	12% 13% 34% 27% 13% 1	500
	11th to 20th	Day	13% 10% 33% 27% 15% 2	500
	21st to end	Day	11% 10% 32% 30% 15% 1	550
April	1st to 10th	Day	13% 11% 29% 27% 18% 2	500
	11th to 20th	Day	10% 9% 31% 28% 18% 4	492
	21st to end	Day	4 6% 21% 36% 24% 9%	500
May	1st to 10th	Day	6% 7% 22% 29% 24% 12%	503
	11th to 20th	Day	8% 4 17% 29% 26% 16%	527
	21st to end	Day	8% 4 12% 22% 32% 23%	573
June	1st to 10th	Day	11% 2 11% 28% 26% 22%	530
	11th to 20th	Day	7% 3 11% 20% 32% 28%	530
	21st to end	Day	4 2 7% 18% 36% 33%	530
July	1st to 10th	Day	7% 3 6% 13% 30% 42%	525
	11th to 20th	Day	6% 1 2 14% 33% 44%	524
	21st to end	Day	6% 2 5% 15% 32% 40%	576
August	1st to 10th	Day	10% 2 6% 16% 29% 36%	526
	11th to 20th	Day	8% 2 4 15% 28% 44%	519
	21st to end	Day	11% 2 5% 20% 33% 29%	583
September	1st to 10th	Day	11% 3 9% 21% 27% 28%	530
	11th to 20th	Day	11% 2 10% 28% 30% 19%	530
	21st to end	Day	9% 2 10% 23% 36% 19%	530
October	1st to 10th	Day	13% 5% 23% 32% 19% 8%	530
	11th to 20th	Day	5% 7% 17% 32% 31% 9%	530
	21st to end	Day	8% 5% 22% 40% 21% 4	583
November	1st to 10th	Day	11% 6% 21% 33% 24% 5%	535
	11th to 20th	Day	14% 6% 28% 34% 15% 3	468
	21st to end	Day	12% 8% 35% 30% 12% 3	300
December	1st to 10th	Day	9% 12% 35% 27% 12% 4	300
	11th to 20th	Day	15% 15% 29% 28% 13%	300
	21st to end	Day	13% 10% 32% 30% 13% 2	330
January	1st to 10th	Night	14% 11% 33% 32% 9%	800
	11th to 20th	Night	12% 11% 25% 38% 14% 1	800
	21st to end	Night	18% 10% 35% 31% 6%	880
February	1st to 10th	Night	15% 6% 31% 38% 10% 1	800
	11th to 20th	Night	15% 9% 32% 35% 9% 1	783
	21st to end	Night	12% 8% 35% 38% 6%	660
March	1st to 10th	Night	12% 9% 33% 37% 10%	800
	11th to 20th	Night	12% 8% 30% 37% 14% 1	800
	21st to end	Night	10% 8% 33% 36% 13%	880
April	1st to 10th	Night	12% 8% 29% 38% 13%	800
	11th to 20th	Night	8% 9% 32% 39% 12% 1	791
	21st to end	Night	6% 4 24% 42% 22% 1	685
May	1st to 10th	Night	5% 4 20% 46% 23% 2	600
	11th to 20th	Night	7% 3 19% 40% 28% 3	591
	21st to end	Night	5% 2 12% 38% 37% 6%	650
June	1st to 10th	Night	12% 2 11% 37% 32% 8%	600
	11th to 20th	Night	6% 1 8% 26% 40% 20%	600
	21st to end	Night	8% 1 6% 22% 44% 20%	600
July	1st to 10th	Night	6% 2 4 19% 45% 23%	585
	11th to 20th	Night	5% 1 3 14% 51% 26%	582
	21st to end	Night	5% 2 3 15% 55% 21%	657
August	1st to 10th	Night	9% 1 4 16% 50% 20%	597
	11th to 20th	Night	6% 2 3 12% 52% 26%	594
	21st to end	Night	11% 2 9% 23% 40% 16%	811
September	1st to 10th	Night	11% 2 11% 23% 39% 14%	800
	11th to 20th	Night	12% 4 9% 33% 33% 8%	800
	21st to end	Night	11% 2 12% 33% 37% 6%	800
October	1st to 10th	Night	13% 3 19% 35% 26% 3	800
	11th to 20th	Night	7% 5% 17% 42% 27% 2	800
	21st to end	Night	9% 3 21% 41% 23% 2	880
November	1st to 10th	Night	9% 5% 24% 41% 20% 2	820
	11th to 20th	Night	12% 6% 23% 42% 16% 1	829
	21st to end	Night	12% 7% 27% 40% 14% 1	800
December	1st to 10th	Night	12% 6% 27% 35% 20% 1	800
	11th to 20th	Night	14% 9% 25% 37% 15% 1	800
	21st to end	Night	15% 8% 27% 36% 14% 1	880

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