Bald Eagle State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bald Eagle State Park clear sky chart from 2005-11-06 to 2026-09-14.

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	15% 9% 3 9% 5% 5% 5% 4 6% 7% 32%	149356
	Night	15% 10% 4 9% 5% 5% 4 4 5% 7% 33%	141672
Transparency	Day	48% 7% 12% 21% 11% 1	152951
	Night	48% 7% 12% 20% 11% 1	146164
Seeing	Day	24% 17% 26% 20% 10% 3	17142
	Night	22% 15% 25% 27% 11% 1	26503

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	14% 16% 6% 16% 6% 4 4 3 4 4 22%	4661
	11th to 20th	Day	10% 14% 9% 19% 9% 6% 4 3 5% 4 16%	5161
	21st to end	Day	15% 14% 5% 10% 6% 5% 4 3 5% 5% 26%	5780
February	1st to 10th	Day	14% 15% 5% 11% 6% 6% 4 4 4 5% 26%	1890
	11th to 20th	Day	14% 14% 5% 12% 6% 4 4 4 6% 5% 27%	1843
	21st to end	Day	17% 13% 4 11% 6% 4 4 3 5% 5% 29%	1719
March	1st to 10th	Day	18% 13% 3 8% 5% 4 4 3 3 4 35%	4966
	11th to 20th	Day	12% 10% 4 10% 6% 5% 5% 4 5% 7% 36%	5090
	21st to end	Day	12% 9% 3 9% 5% 5% 5% 4 5% 5% 36%	5665
April	1st to 10th	Day	16% 13% 3 9% 5% 6% 3 2 5% 6% 32%	2520
	11th to 20th	Day	15% 10% 3 7% 4 4 4 4 6% 6% 35%	2494
	21st to end	Day	18% 8% 3 7% 5% 5% 4 4 5% 6% 35%	2590
May	1st to 10th	Day	23% 7% 3 7% 5% 6% 6% 4 6% 7% 27%	7642
	11th to 20th	Day	19% 8% 3 8% 5% 5% 4 4 6% 7% 31%	8198
	21st to end	Day	21% 7% 2 7% 4 4 5% 4 6% 6% 33%	9060
June	1st to 10th	Day	12% 7% 2 7% 5% 5% 6% 5% 6% 7% 37%	2940
	11th to 20th	Day	15% 5% 3 7% 5% 6% 5% 5% 6% 8% 36%	2940
	21st to end	Day	12% 6% 2 6% 5% 4 5% 5% 6% 10% 38%	2940
July	1st to 10th	Day	10% 6% 3 8% 6% 5% 5% 4 6% 8% 38%	8280
	11th to 20th	Day	6% 5% 2 8% 6% 6% 6% 5% 8% 11% 35%	8280
	21st to end	Day	11% 6% 3 7% 5% 5% 5% 4 7% 9% 39%	8366
August	1st to 10th	Day	17% 8% 3 8% 6% 6% 6% 4 6% 8% 28%	6014
	11th to 20th	Day	14% 7% 3 7% 5% 6% 6% 4 7% 9% 31%	5868
	21st to end	Day	10% 6% 2 6% 5% 6% 6% 5% 8% 10% 37%	6080
September	1st to 10th	Day	16% 5% 2 6% 4 5% 4 4 5% 6% 43%	2520
	11th to 20th	Day	13% 6% 2 5% 4 4 5% 3 5% 7% 47%	2436
	21st to end	Day	21% 8% 3 6% 4 4 4 4 5% 6% 35%	2087
October	1st to 10th	Day	15% 8% 3 6% 4 5% 4 3 6% 7% 40%	2000
	11th to 20th	Day	17% 7% 3 8% 5% 5% 5% 4 5% 6% 36%	2000
	21st to end	Day	17% 9% 3 7% 4 5% 5% 4 5% 6% 35%	2200
November	1st to 10th	Day	10% 7% 3 8% 5% 4 5% 3 6% 6% 43%	1909
	11th to 20th	Day	14% 12% 4 9% 6% 4 5% 4 5% 5% 31%	1743
	21st to end	Day	17% 13% 4 10% 5% 4 4 5% 5% 6% 29%	1680
December	1st to 10th	Day	15% 15% 7% 15% 7% 6% 4 3 4 4 19%	2680
	11th to 20th	Day	21% 15% 4 9% 4 4 3 3 5% 5% 26%	3066
	21st to end	Day	18% 18% 6% 12% 6% 5% 5% 3 5% 5% 16%	4048
January	1st to 10th	Night	11% 15% 6% 18% 7% 5% 4 4 4 5% 20%	8234
	11th to 20th	Night	11% 13% 7% 16% 7% 6% 5% 4 5% 6% 20%	7722
	21st to end	Night	14% 13% 4 10% 8% 6% 5% 4 4 4 27%	8401
February	1st to 10th	Night	14% 13% 4 10% 6% 5% 4 4 6% 5% 29%	2730
	11th to 20th	Night	16% 12% 5% 10% 5% 5% 5% 4 5% 6% 28%	2663
	21st to end	Night	16% 11% 4 11% 6% 4 4 4 4 5% 31%	2086
March	1st to 10th	Night	19% 12% 4 8% 4 4 3 3 4 5% 33%	5078
	11th to 20th	Night	10% 11% 4 7% 5% 4 4 3 5% 7% 40%	5089
	21st to end	Night	14% 10% 4 9% 5% 4 4 4 4 6% 38%	5508
April	1st to 10th	Night	19% 12% 3 8% 5% 4 3 4 4 6% 31%	2100
	11th to 20th	Night	16% 8% 2 7% 5% 5% 4 4 5% 8% 36%	2075
	21st to end	Night	17% 8% 2 6% 5% 4 5% 4 5% 6% 38%	2047
May	1st to 10th	Night	22% 9% 3 7% 4 5% 4 4 5% 6% 31%	5257
	11th to 20th	Night	18% 9% 3 8% 5% 4 4 3 5% 6% 34%	4662
	21st to end	Night	21% 8% 3 7% 4 4 4 3 5% 7% 35%	5114
June	1st to 10th	Night	13% 6% 2 5% 5% 4 4 4 5% 8% 45%	1680
	11th to 20th	Night	12% 6% 3 6% 4 5% 5% 4 5% 9% 40%	1680
	21st to end	Night	11% 5% 2 6% 5% 4 5% 4 7% 10% 41%	1680
July	1st to 10th	Night	10% 7% 2 7% 5% 5% 4 4 6% 10% 39%	4680
	11th to 20th	Night	7% 5% 2 8% 5% 5% 6% 5% 8% 11% 37%	4680
	21st to end	Night	10% 6% 3 8% 4 5% 5% 4 5% 8% 43%	5693
August	1st to 10th	Night	15% 7% 3 8% 5% 6% 6% 4 7% 8% 32%	4135
	11th to 20th	Night	13% 7% 3 7% 4 6% 5% 4 6% 7% 38%	4118
	21st to end	Night	10% 5% 2 7% 5% 5% 4 5% 7% 9% 41%	5045
September	1st to 10th	Night	14% 5% 2 6% 4 4 5% 3 5% 8% 45%	2100
	11th to 20th	Night	11% 6% 3 5% 3 3 3 3 5% 8% 50%	2031
	21st to end	Night	18% 7% 2 7% 4 4 5% 3 5% 7% 38%	2306
October	1st to 10th	Night	16% 6% 2 6% 3 4 4 3 5% 7% 45%	2400
	11th to 20th	Night	16% 7% 3 7% 5% 3 4 4 6% 6% 41%	2400
	21st to end	Night	19% 8% 3 6% 4 3 5% 3 5% 6% 38%	2640
November	1st to 10th	Night	10% 7% 3 6% 4 3 3 3 5% 7% 48%	2608
	11th to 20th	Night	16% 12% 4 7% 5% 5% 4 3 6% 7% 32%	2872
	21st to end	Night	15% 12% 4 8% 4 5% 5% 3 6% 6% 31%	2940
December	1st to 10th	Night	13% 12% 5% 11% 6% 6% 5% 5% 6% 7% 24%	4720
	11th to 20th	Night	21% 13% 4 9% 5% 4 4 3 5% 6% 27%	5348
	21st to end	Night	19% 14% 5% 12% 6% 5% 5% 4 5% 5% 20%	7150

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	62% 7% 12% 12% 5% 1	4662
	11th to 20th	Day	69% 6% 8% 12% 6% 1	5195
	21st to end	Day	58% 5% 12% 17% 7%	5780
February	1st to 10th	Day	61% 5% 10% 16% 7% 1	1890
	11th to 20th	Day	57% 6% 9% 21% 7% 1	1852
	21st to end	Day	57% 4 10% 20% 7% 2	1719
March	1st to 10th	Day	52% 5% 11% 21% 9% 3	4969
	11th to 20th	Day	46% 6% 15% 21% 8% 3	5090
	21st to end	Day	48% 6% 10% 18% 15% 3	5665
April	1st to 10th	Day	53% 5% 10% 19% 12% 2	2520
	11th to 20th	Day	47% 6% 12% 19% 15% 2	2494
	21st to end	Day	49% 6% 9% 20% 14% 3	2590
May	1st to 10th	Day	53% 8% 11% 18% 8% 1	7651
	11th to 20th	Day	50% 7% 11% 20% 10% 1	8202
	21st to end	Day	48% 7% 10% 22% 11% 1	9061
June	1st to 10th	Day	43% 7% 11% 22% 15% 1	2940
	11th to 20th	Day	45% 6% 14% 20% 13% 1	2940
	21st to end	Day	39% 8% 13% 27% 13%	2940
July	1st to 10th	Day	42% 8% 12% 24% 13% 1	8210
	11th to 20th	Day	37% 10% 15% 28% 10%	8205
	21st to end	Day	39% 8% 11% 24% 18% 1	8181
August	1st to 10th	Day	51% 9% 12% 17% 10% 1	6001
	11th to 20th	Day	44% 10% 14% 25% 7%	5907
	21st to end	Day	36% 10% 15% 26% 12% 1	6080
September	1st to 10th	Day	41% 6% 11% 24% 16% 2	2520
	11th to 20th	Day	36% 5% 11% 26% 20% 2	2436
	21st to end	Day	49% 5% 10% 19% 16% 1	2087
October	1st to 10th	Day	39% 6% 10% 26% 16% 4	3260
	11th to 20th	Day	40% 6% 10% 23% 18% 2	3240
	21st to end	Day	33% 5% 16% 30% 15% 1	3538
November	1st to 10th	Day	40% 5% 13% 22% 16% 3	1909
	11th to 20th	Day	54% 5% 10% 20% 9% 2	1743
	21st to end	Day	55% 6% 11% 20% 7% 1	1680
December	1st to 10th	Day	66% 7% 10% 13% 5%	2680
	11th to 20th	Day	59% 5% 13% 18% 5%	3066
	21st to end	Day	67% 6% 12% 9% 4 1	4048
January	1st to 10th	Night	61% 8% 11% 14% 6% 1	8234
	11th to 20th	Night	61% 7% 11% 11% 8% 1	7763
	21st to end	Night	57% 7% 10% 18% 8% 1	8401
February	1st to 10th	Night	54% 5% 12% 20% 8% 1	2730
	11th to 20th	Night	55% 5% 10% 19% 10%	2665
	21st to end	Night	55% 5% 9% 19% 11% 1	2086
March	1st to 10th	Night	54% 5% 11% 19% 10% 2	5088
	11th to 20th	Night	41% 7% 17% 24% 8% 4	5090
	21st to end	Night	47% 5% 9% 19% 18% 2	5508
April	1st to 10th	Night	53% 5% 9% 18% 14% 1	2100
	11th to 20th	Night	46% 7% 10% 21% 14% 2	2075
	21st to end	Night	45% 6% 9% 24% 13% 3	2047
May	1st to 10th	Night	53% 7% 11% 18% 10% 2	5264
	11th to 20th	Night	49% 8% 11% 20% 11% 1	4663
	21st to end	Night	48% 7% 11% 20% 12% 2	5115
June	1st to 10th	Night	38% 7% 12% 26% 16% 1	1680
	11th to 20th	Night	40% 7% 14% 22% 14% 2	1680
	21st to end	Night	36% 8% 14% 28% 14% 1	1680
July	1st to 10th	Night	40% 9% 13% 22% 15% 1	4640
	11th to 20th	Night	35% 10% 16% 27% 11%	4632
	21st to end	Night	36% 9% 11% 21% 21% 1	5563
August	1st to 10th	Night	48% 9% 13% 19% 9% 1	4124
	11th to 20th	Night	41% 9% 14% 26% 10%	4145
	21st to end	Night	35% 9% 15% 28% 11% 1	5045
September	1st to 10th	Night	39% 6% 11% 25% 17% 3	2100
	11th to 20th	Night	32% 5% 12% 29% 20% 1	2031
	21st to end	Night	45% 6% 11% 21% 16% 1	2306
October	1st to 10th	Night	39% 6% 12% 22% 20% 1	3920
	11th to 20th	Night	35% 6% 11% 26% 19% 4	3899
	21st to end	Night	35% 4 14% 26% 18% 2	4252
November	1st to 10th	Night	37% 4 13% 25% 18% 2	2608
	11th to 20th	Night	50% 5% 10% 21% 12% 3	2872
	21st to end	Night	51% 5% 13% 22% 8% 1	2940
December	1st to 10th	Night	55% 9% 14% 17% 5%	4720
	11th to 20th	Night	57% 5% 14% 18% 6%	5348
	21st to end	Night	62% 7% 11% 15% 5%	7150

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	35% 26% 26% 8% 4 1	220
	11th to 20th	Day	40% 24% 26% 9% 1	314
	21st to end	Day	31% 31% 27% 9% 2	363
February	1st to 10th	Day	31% 29% 26% 10% 4	330
	11th to 20th	Day	40% 23% 33% 4 1	330
	21st to end	Day	33% 25% 27% 13% 2	435
March	1st to 10th	Day	33% 23% 26% 15% 3	540
	11th to 20th	Day	34% 23% 24% 15% 2 2	540
	21st to end	Day	31% 24% 26% 14% 4 2	594
April	1st to 10th	Day	33% 22% 26% 14% 4 1	540
	11th to 20th	Day	29% 23% 23% 16% 7% 3	532
	21st to end	Day	27% 21% 31% 13% 7% 1	540
May	1st to 10th	Day	33% 18% 26% 14% 7% 2	543
	11th to 20th	Day	23% 18% 28% 18% 8% 4	567
	21st to end	Day	23% 13% 27% 21% 13% 4	617
June	1st to 10th	Day	17% 14% 29% 24% 13% 3	570
	11th to 20th	Day	20% 15% 25% 24% 12% 3	570
	21st to end	Day	14% 15% 31% 27% 10% 3	570
July	1st to 10th	Day	12% 8% 26% 30% 17% 7%	565
	11th to 20th	Day	8% 8% 32% 29% 17% 6%	564
	21st to end	Day	13% 9% 30% 28% 15% 5%	620
August	1st to 10th	Day	13% 8% 25% 27% 21% 7%	566
	11th to 20th	Day	15% 8% 23% 28% 18% 8%	559
	21st to end	Day	13% 11% 24% 25% 16% 10%	627
September	1st to 10th	Day	17% 10% 22% 24% 18% 9%	570
	11th to 20th	Day	14% 7% 21% 26% 24% 9%	542
	21st to end	Day	25% 12% 24% 20% 15% 4	530
October	1st to 10th	Day	20% 12% 22% 23% 17% 6%	530
	11th to 20th	Day	24% 17% 28% 21% 8% 2	530
	21st to end	Day	24% 18% 30% 19% 8% 1	583
November	1st to 10th	Day	21% 18% 25% 24% 10% 2	456
	11th to 20th	Day	31% 23% 23% 17% 6% 1	283
	21st to end	Day	30% 25% 32% 11% 3	220
December	1st to 10th	Day	35% 28% 24% 10% 3 1	220
	11th to 20th	Day	36% 22% 27% 14% 1	220
	21st to end	Day	33% 24% 27% 10% 5%	242
January	1st to 10th	Night	23% 26% 32% 16% 3	840
	11th to 20th	Night	28% 22% 27% 20% 3	840
	21st to end	Night	24% 25% 30% 20% 2	924
February	1st to 10th	Night	27% 19% 29% 23% 2	840
	11th to 20th	Night	31% 23% 30% 15% 1	823
	21st to end	Night	29% 21% 31% 18% 2	692
March	1st to 10th	Night	29% 19% 28% 20% 3	840
	11th to 20th	Night	28% 18% 27% 21% 5%	840
	21st to end	Night	23% 19% 31% 21% 5%	924
April	1st to 10th	Night	29% 18% 28% 20% 4	840
	11th to 20th	Night	22% 19% 29% 22% 8% 1	831
	21st to end	Night	24% 12% 28% 28% 7%	787
May	1st to 10th	Night	24% 10% 23% 31% 10% 1	630
	11th to 20th	Night	17% 11% 28% 34% 10%	425
	21st to end	Night	14% 9% 25% 32% 19% 1	455
June	1st to 10th	Night	15% 7% 22% 38% 18% 1	420
	11th to 20th	Night	14% 8% 21% 43% 14%	420
	21st to end	Night	12% 5% 28% 38% 18%	420
July	1st to 10th	Night	11% 8% 18% 37% 24% 2	410
	11th to 20th	Night	7% 2 20% 41% 28% 2	408
	21st to end	Night	10% 5% 18% 42% 23% 2	672
August	1st to 10th	Night	10% 4 15% 41% 28% 3	627
	11th to 20th	Night	13% 7% 12% 37% 27% 5%	634
	21st to end	Night	12% 6% 15% 37% 27% 3	924
September	1st to 10th	Night	16% 6% 19% 31% 25% 3	840
	11th to 20th	Night	13% 7% 18% 27% 29% 6%	813
	21st to end	Night	21% 9% 19% 29% 20% 3	800
October	1st to 10th	Night	20% 9% 20% 26% 21% 4	800
	11th to 20th	Night	20% 15% 24% 30% 10% 1	800
	21st to end	Night	26% 15% 23% 28% 7% 1	880
November	1st to 10th	Night	16% 14% 26% 33% 10% 1	820
	11th to 20th	Night	28% 16% 23% 25% 6% 2	840
	21st to end	Night	27% 18% 27% 23% 4 1	840
December	1st to 10th	Night	28% 20% 30% 17% 5%	840
	11th to 20th	Night	30% 17% 28% 22% 4	840
	21st to end	Night	25% 20% 27% 26% 3	924

Page generated at 2026-09-11 04:11:53. Version ac07

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