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 2025-05-11.

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% 10% 4 9% 5% 5% 5% 4 5% 7% 32%	113962
	Night	15% 10% 4 9% 5% 5% 4 4 5% 7% 33%	114957
Transparency	Day	49% 6% 12% 21% 11% 2	117601
	Night	48% 7% 12% 20% 11% 2	119481
Seeing	Day	24% 17% 26% 20% 10% 3	15346
	Night	22% 15% 25% 27% 11% 1	24899

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% 16% 7% 15% 5% 4 4 3 3 4 26%	3597
	11th to 20th	Day	11% 16% 11% 17% 9% 6% 4 3 5% 4 14%	3955
	21st to end	Day	17% 17% 6% 10% 5% 5% 4 3 5% 5% 24%	4466
February	1st to 10th	Day	15% 15% 5% 11% 6% 6% 4 4 4 5% 24%	1800
	11th to 20th	Day	13% 13% 4 12% 6% 4 4 4 6% 6% 28%	1753
	21st to end	Day	18% 11% 4 11% 6% 4 4 3 5% 5% 28%	1639
March	1st to 10th	Day	18% 13% 3 8% 5% 4 4 3 3 4 35%	4858
	11th to 20th	Day	12% 9% 4 9% 6% 5% 5% 4 5% 7% 36%	4980
	21st to end	Day	12% 10% 3 9% 5% 5% 5% 3 5% 5% 37%	5543
April	1st to 10th	Day	16% 13% 3 9% 5% 6% 4 3 5% 6% 32%	2400
	11th to 20th	Day	16% 10% 3 7% 5% 4 4 4 6% 6% 35%	2374
	21st to end	Day	18% 8% 3 7% 5% 4 4 4 4 6% 35%	2467
May	1st to 10th	Day	27% 7% 3 6% 5% 4 5% 3 5% 7% 29%	4238
	11th to 20th	Day	21% 9% 4 8% 6% 5% 4 4 5% 7% 28%	4388
	21st to end	Day	12% 6% 2 7% 4 5% 5% 4 7% 9% 39%	4837
June	1st to 10th	Day	13% 7% 2 7% 5% 6% 6% 5% 6% 7% 35%	2660
	11th to 20th	Day	14% 6% 2 7% 5% 6% 5% 4 6% 8% 36%	2660
	21st to end	Day	11% 6% 2 6% 5% 4 5% 5% 6% 10% 38%	2660
July	1st to 10th	Day	7% 6% 3 8% 6% 5% 6% 5% 7% 10% 37%	4440
	11th to 20th	Day	6% 5% 2 7% 5% 6% 7% 5% 8% 11% 37%	4440
	21st to end	Day	9% 7% 3 8% 5% 5% 5% 5% 8% 8% 36%	4478
August	1st to 10th	Day	18% 8% 3 7% 5% 5% 5% 4 6% 8% 32%	4104
	11th to 20th	Day	12% 7% 3 8% 6% 6% 7% 4 7% 8% 32%	3990
	21st to end	Day	12% 7% 2 5% 4 5% 5% 4 7% 9% 41%	4180
September	1st to 10th	Day	17% 6% 2 6% 4 5% 4 3 5% 6% 43%	2280
	11th to 20th	Day	13% 6% 2 5% 4 3 5% 3 5% 7% 47%	2280
	21st to end	Day	20% 8% 3 6% 4 3 4 4 5% 6% 36%	1983
October	1st to 10th	Day	15% 8% 3 7% 5% 5% 4 3 6% 7% 38%	1900
	11th to 20th	Day	17% 8% 3 8% 5% 5% 5% 3 5% 6% 36%	1900
	21st to end	Day	17% 9% 3 7% 4 5% 5% 4 5% 6% 35%	2090
November	1st to 10th	Day	10% 7% 2 8% 5% 4 5% 3 6% 6% 43%	1816
	11th to 20th	Day	14% 11% 3 9% 6% 4 6% 4 5% 6% 32%	1660
	21st to end	Day	17% 13% 3 9% 5% 4 4 5% 5% 6% 29%	1600
December	1st to 10th	Day	15% 15% 7% 15% 6% 6% 4 3 4 4 20%	2600
	11th to 20th	Day	22% 16% 4 9% 3 4 3 3 5% 5% 26%	2986
	21st to end	Day	18% 18% 6% 12% 6% 6% 5% 3 5% 5% 16%	3960
January	1st to 10th	Night	12% 12% 6% 18% 6% 4 4 4 4 5% 24%	6349
	11th to 20th	Night	12% 14% 7% 15% 7% 6% 4 4 5% 6% 19%	5928
	21st to end	Night	17% 15% 5% 11% 5% 6% 6% 4 4 4 24%	6490
February	1st to 10th	Night	15% 13% 4 10% 6% 5% 4 4 6% 5% 29%	2600
	11th to 20th	Night	15% 11% 4 10% 5% 5% 5% 4 5% 7% 29%	2533
	21st to end	Night	16% 11% 4 10% 6% 4 4 4 4 5% 31%	1990
March	1st to 10th	Night	19% 12% 5% 9% 4 4 3 3 4 5% 33%	4966
	11th to 20th	Night	10% 11% 4 7% 5% 4 4 3 5% 7% 40%	4979
	21st to end	Night	14% 10% 4 9% 5% 4 4 4 4 6% 38%	5388
April	1st to 10th	Night	19% 13% 3 8% 5% 4 3 4 4 7% 31%	2000
	11th to 20th	Night	16% 8% 2 7% 5% 4 4 4 5% 8% 36%	1975
	21st to end	Night	17% 8% 2 6% 5% 5% 5% 4 5% 6% 38%	1950
May	1st to 10th	Night	27% 8% 3 7% 4 5% 5% 3 4 5% 29%	2923
	11th to 20th	Night	21% 10% 3 8% 5% 4 4 4 5% 6% 30%	2511
	21st to end	Night	11% 7% 2 7% 6% 5% 5% 4 6% 9% 38%	2738
June	1st to 10th	Night	13% 6% 2 6% 5% 4 4 4 5% 8% 44%	1520
	11th to 20th	Night	11% 6% 3 6% 4 5% 6% 4 6% 10% 41%	1520
	21st to end	Night	10% 5% 2 6% 5% 4 5% 4 8% 10% 41%	1520
July	1st to 10th	Night	9% 6% 2 7% 5% 6% 4 4 7% 9% 41%	2520
	11th to 20th	Night	6% 4 2 6% 5% 5% 6% 5% 7% 11% 44%	2520
	21st to end	Night	11% 6% 3 8% 4 5% 4 4 5% 7% 41%	3071
August	1st to 10th	Night	17% 5% 2 6% 4 5% 5% 4 6% 8% 36%	2825
	11th to 20th	Night	14% 7% 3 7% 3 5% 5% 3 6% 7% 40%	2807
	21st to end	Night	12% 5% 2 7% 4 4 4 4 7% 8% 44%	3476
September	1st to 10th	Night	15% 6% 2 6% 4 4 4 3 5% 7% 45%	1900
	11th to 20th	Night	11% 6% 3 4 3 3 3 2 4 8% 52%	1900
	21st to end	Night	18% 6% 2 7% 5% 4 4 3 5% 6% 39%	2190
October	1st to 10th	Night	16% 7% 2 6% 4 4 4 3 5% 7% 43%	2280
	11th to 20th	Night	16% 7% 3 7% 4 3 4 4 6% 6% 41%	2280
	21st to end	Night	19% 9% 3 6% 4 3 5% 3 5% 6% 37%	2508
November	1st to 10th	Night	10% 7% 3 6% 4 3 3 3 5% 7% 48%	2481
	11th to 20th	Night	16% 11% 4 6% 5% 5% 4 3 6% 7% 33%	2735
	21st to end	Night	15% 12% 3 8% 4 6% 5% 3 6% 6% 32%	2800
December	1st to 10th	Night	13% 12% 5% 11% 6% 6% 5% 5% 6% 7% 24%	4580
	11th to 20th	Night	21% 13% 4 8% 5% 4 4 3 5% 6% 27%	5208
	21st to end	Night	19% 14% 5% 12% 6% 5% 5% 4 5% 5% 20%	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	61% 6% 11% 15% 6% 1	3598
	11th to 20th	Day	71% 6% 8% 11% 4 1	3989
	21st to end	Day	61% 5% 10% 17% 7% 1	4466
February	1st to 10th	Day	62% 5% 10% 15% 7% 1	1800
	11th to 20th	Day	56% 6% 9% 21% 7% 1	1762
	21st to end	Day	57% 4 10% 20% 8% 2	1639
March	1st to 10th	Day	52% 5% 11% 20% 9% 3	4861
	11th to 20th	Day	46% 6% 16% 21% 8% 3	4980
	21st to end	Day	48% 6% 10% 18% 16% 3	5543
April	1st to 10th	Day	53% 5% 10% 19% 12% 2	2400
	11th to 20th	Day	48% 5% 11% 19% 15% 2	2374
	21st to end	Day	49% 6% 9% 20% 14% 3	2467
May	1st to 10th	Day	54% 5% 9% 20% 9% 1	4250
	11th to 20th	Day	55% 7% 12% 16% 8% 2	4392
	21st to end	Day	38% 8% 13% 25% 13% 2	4837
June	1st to 10th	Day	45% 8% 11% 22% 14% 1	2660
	11th to 20th	Day	45% 6% 14% 21% 13% 1	2660
	21st to end	Day	39% 8% 12% 27% 13%	2660
July	1st to 10th	Day	39% 9% 15% 25% 11% 1	4370
	11th to 20th	Day	36% 9% 15% 24% 14% 1	4365
	21st to end	Day	41% 8% 12% 23% 15%	4335
August	1st to 10th	Day	48% 8% 14% 20% 9%	4091
	11th to 20th	Day	44% 9% 12% 26% 9%	4029
	21st to end	Day	38% 7% 12% 29% 12% 2	4180
September	1st to 10th	Day	42% 5% 9% 25% 16% 3	2280
	11th to 20th	Day	36% 5% 11% 25% 20% 2	2280
	21st to end	Day	48% 5% 10% 19% 16% 1	1983
October	1st to 10th	Day	40% 6% 11% 25% 15% 4	3160
	11th to 20th	Day	40% 6% 10% 24% 18% 2	3140
	21st to end	Day	33% 5% 16% 30% 15% 1	3428
November	1st to 10th	Day	40% 5% 13% 22% 16% 3	1816
	11th to 20th	Day	52% 5% 10% 21% 10% 2	1660
	21st to end	Day	55% 6% 11% 21% 7% 1	1600
December	1st to 10th	Day	65% 7% 10% 13% 5%	2600
	11th to 20th	Day	59% 5% 13% 18% 5%	2986
	21st to end	Day	67% 6% 12% 9% 4 1	3960
January	1st to 10th	Night	59% 7% 11% 16% 7% 1	6349
	11th to 20th	Night	61% 7% 12% 11% 7% 2	5969
	21st to end	Night	59% 7% 10% 15% 8% 1	6490
February	1st to 10th	Night	55% 5% 13% 20% 7% 1	2600
	11th to 20th	Night	54% 5% 10% 20% 10% 1	2535
	21st to end	Night	55% 5% 9% 18% 11% 2	1990
March	1st to 10th	Night	54% 5% 11% 19% 9% 2	4976
	11th to 20th	Night	41% 7% 17% 24% 8% 4	4980
	21st to end	Night	47% 5% 9% 18% 18% 2	5388
April	1st to 10th	Night	53% 5% 9% 18% 14% 1	2000
	11th to 20th	Night	46% 6% 10% 21% 14% 2	1975
	21st to end	Night	45% 6% 9% 24% 14% 3	1950
May	1st to 10th	Night	56% 5% 9% 18% 9% 2	2930
	11th to 20th	Night	54% 8% 12% 16% 10% 1	2512
	21st to end	Night	39% 8% 15% 20% 13% 5%	2739
June	1st to 10th	Night	38% 7% 12% 25% 15% 2	1520
	11th to 20th	Night	39% 7% 15% 23% 14% 2	1520
	21st to end	Night	36% 8% 13% 29% 14% 1	1520
July	1st to 10th	Night	39% 8% 13% 22% 15% 3	2480
	11th to 20th	Night	31% 10% 16% 27% 16% 1	2472
	21st to end	Night	40% 8% 12% 18% 20% 2	2973
August	1st to 10th	Night	44% 9% 15% 23% 9%	2814
	11th to 20th	Night	41% 7% 12% 28% 12%	2834
	21st to end	Night	34% 8% 13% 32% 12% 2	3476
September	1st to 10th	Night	39% 6% 10% 25% 17% 3	1900
	11th to 20th	Night	32% 5% 12% 29% 21% 1	1900
	21st to end	Night	44% 6% 11% 22% 16% 1	2190
October	1st to 10th	Night	40% 7% 12% 22% 19% 1	3800
	11th to 20th	Night	35% 6% 11% 26% 19% 4	3779
	21st to end	Night	34% 4 14% 27% 18% 2	4120
November	1st to 10th	Night	36% 4 13% 25% 18% 2	2481
	11th to 20th	Night	49% 5% 10% 21% 12% 3	2735
	21st to end	Night	50% 6% 13% 22% 8% 1	2800
December	1st to 10th	Night	55% 9% 14% 17% 4	4580
	11th to 20th	Night	58% 5% 14% 18% 6%	5208
	21st to end	Night	61% 8% 11% 15% 5%	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	34% 25% 28% 9% 4 2	200
	11th to 20th	Day	38% 23% 29% 9% 1	285
	21st to end	Day	28% 32% 28% 9% 3	330
February	1st to 10th	Day	32% 30% 26% 9% 3	300
	11th to 20th	Day	40% 24% 32% 3 1	300
	21st to end	Day	34% 24% 27% 14% 2	403
March	1st to 10th	Day	32% 23% 26% 15% 3	500
	11th to 20th	Day	32% 23% 26% 15% 2 2	500
	21st to end	Day	31% 22% 27% 14% 4 2	550
April	1st to 10th	Day	32% 22% 26% 15% 4 1	500
	11th to 20th	Day	29% 22% 23% 15% 8% 3	492
	21st to end	Day	26% 21% 31% 13% 7% 2	500
May	1st to 10th	Day	32% 17% 26% 14% 8% 3	503
	11th to 20th	Day	23% 17% 27% 19% 9% 5%	487
	21st to end	Day	19% 12% 27% 22% 15% 4	529
June	1st to 10th	Day	19% 13% 29% 24% 13% 2	490
	11th to 20th	Day	18% 14% 24% 27% 14% 3	490
	21st to end	Day	14% 16% 31% 26% 10% 3	490
July	1st to 10th	Day	12% 9% 26% 29% 18% 7%	485
	11th to 20th	Day	8% 8% 31% 30% 17% 6%	484
	21st to end	Day	12% 10% 30% 28% 14% 5%	532
August	1st to 10th	Day	12% 8% 26% 27% 21% 6%	486
	11th to 20th	Day	15% 8% 23% 27% 18% 8%	479
	21st to end	Day	14% 11% 24% 26% 16% 10%	539
September	1st to 10th	Day	19% 10% 20% 25% 18% 9%	490
	11th to 20th	Day	14% 7% 21% 26% 22% 9%	490
	21st to end	Day	25% 12% 25% 20% 15% 4	490
October	1st to 10th	Day	22% 12% 23% 22% 17% 5%	490
	11th to 20th	Day	24% 17% 27% 21% 9% 2	490
	21st to end	Day	24% 18% 29% 20% 9% 1	539
November	1st to 10th	Day	20% 18% 25% 24% 11% 2	423
	11th to 20th	Day	28% 23% 24% 18% 5% 1	260
	21st to end	Day	28% 26% 32% 12% 4	200
December	1st to 10th	Day	36% 26% 23% 11% 4 1	200
	11th to 20th	Day	37% 21% 27% 14% 1 1	200
	21st to end	Day	33% 22% 27% 11% 6%	220
January	1st to 10th	Night	23% 26% 32% 16% 3	800
	11th to 20th	Night	28% 21% 28% 21% 4	800
	21st to end	Night	23% 25% 30% 21% 2	880
February	1st to 10th	Night	28% 20% 29% 21% 2	800
	11th to 20th	Night	31% 24% 29% 15% 1	783
	21st to end	Night	28% 21% 30% 18% 2	660
March	1st to 10th	Night	28% 19% 29% 20% 4	800
	11th to 20th	Night	27% 19% 27% 22% 6%	800
	21st to end	Night	23% 19% 30% 21% 6%	880
April	1st to 10th	Night	29% 18% 29% 20% 5%	800
	11th to 20th	Night	23% 18% 29% 22% 7% 1	791
	21st to end	Night	25% 12% 28% 28% 8%	750
May	1st to 10th	Night	25% 10% 22% 32% 11% 1	600
	11th to 20th	Night	17% 12% 28% 34% 10%	386
	21st to end	Night	12% 9% 24% 33% 21% 1	411
June	1st to 10th	Night	14% 8% 21% 39% 18% 1	380
	11th to 20th	Night	13% 8% 20% 44% 15%	380
	21st to end	Night	11% 5% 28% 39% 17%	380
July	1st to 10th	Night	11% 8% 19% 36% 24% 2	370
	11th to 20th	Night	7% 2 20% 40% 29% 2	368
	21st to end	Night	10% 5% 19% 41% 23% 2	608
August	1st to 10th	Night	10% 4 16% 41% 27% 2	567
	11th to 20th	Night	13% 6% 11% 38% 27% 5%	573
	21st to end	Night	12% 6% 15% 36% 28% 3	836
September	1st to 10th	Night	17% 6% 19% 31% 25% 3	760
	11th to 20th	Night	13% 7% 19% 26% 29% 6%	760
	21st to end	Night	20% 9% 18% 29% 20% 3	760
October	1st to 10th	Night	20% 10% 20% 26% 20% 4	760
	11th to 20th	Night	20% 15% 24% 29% 10% 1	760
	21st to end	Night	26% 15% 23% 28% 8% 1	836
November	1st to 10th	Night	16% 14% 27% 33% 10% 1	780
	11th to 20th	Night	27% 16% 23% 26% 6% 2	800
	21st to end	Night	26% 18% 27% 24% 5% 1	800
December	1st to 10th	Night	29% 19% 29% 18% 5%	800
	11th to 20th	Night	30% 16% 27% 23% 4	800
	21st to end	Night	25% 20% 26% 26% 3	880

Page generated at 2025-05-08 09:33:58. Version ac07

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