Susquehannock State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Susquehannock State Park clear sky chart from 2005-11-06 to 2026-07-01.

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% 6% 2 6% 4 4 4 4 6% 7% 41%	137994
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	134395
Transparency	Day	40% 7% 12% 23% 16% 3	141583
	Night	40% 6% 11% 23% 17% 3	138877
Seeing	Day	20% 14% 27% 23% 12% 4	17059
	Night	18% 12% 30% 29% 11% 1	26443

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	13% 6% 2 7% 4 5% 4 4 5% 6% 45%	4661
	11th to 20th	Day	14% 8% 2 8% 4 4 4 2 4 4 45%	5078
	21st to end	Day	14% 6% 3 6% 5% 5% 5% 4 6% 7% 40%	5780
February	1st to 10th	Day	13% 9% 2 6% 4 4 4 3 6% 8% 40%	1890
	11th to 20th	Day	17% 8% 3 6% 5% 5% 4 3 5% 6% 39%	1942
	21st to end	Day	17% 12% 3 7% 3 3 3 3 4 5% 40%	1730
March	1st to 10th	Day	19% 5% 1 5% 3 4 3 3 4 5% 46%	4767
	11th to 20th	Day	12% 7% 3 6% 4 4 4 3 5% 7% 46%	5090
	21st to end	Day	17% 7% 2 6% 4 4 4 3 5% 5% 42%	5807
April	1st to 10th	Day	15% 7% 2 6% 5% 5% 4 4 5% 7% 40%	2520
	11th to 20th	Day	14% 6% 2 5% 4 4 4 4 5% 8% 43%	2494
	21st to end	Day	17% 6% 2 5% 4 4 4 4 6% 7% 41%	2520
May	1st to 10th	Day	22% 7% 3 5% 4 4 5% 3 6% 7% 34%	7487
	11th to 20th	Day	20% 6% 2 6% 4 4 5% 4 5% 8% 36%	8221
	21st to end	Day	23% 5% 2 6% 4 4 4 4 6% 7% 36%	9045
June	1st to 10th	Day	11% 6% 2 6% 5% 4 5% 4 7% 10% 39%	2940
	11th to 20th	Day	12% 6% 2 7% 4 5% 5% 5% 7% 9% 39%	2940
	21st to end	Day	11% 4 2 5% 4 5% 5% 5% 6% 10% 42%	2940
July	1st to 10th	Day	7% 5% 2 6% 5% 5% 6% 4 8% 10% 41%	6360
	11th to 20th	Day	10% 7% 3 7% 5% 6% 7% 6% 8% 11% 30%	6360
	21st to end	Day	9% 6% 2 7% 5% 5% 5% 4 8% 10% 39%	6564
August	1st to 10th	Day	18% 5% 2 7% 4 5% 5% 5% 7% 8% 33%	4234
	11th to 20th	Day	12% 5% 2 6% 5% 4 6% 4 8% 9% 39%	3944
	21st to end	Day	11% 5% 2 5% 4 4 4 3 6% 7% 50%	4312
September	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 5% 6% 46%	2400
	11th to 20th	Day	13% 5% 2 5% 3 4 3 3 5% 8% 50%	2400
	21st to end	Day	20% 7% 3 6% 4 3 4 3 5% 7% 36%	2135
October	1st to 10th	Day	17% 6% 2 6% 4 3 4 3 5% 6% 46%	2000
	11th to 20th	Day	17% 5% 2 5% 3 3 4 4 5% 6% 47%	2000
	21st to end	Day	15% 6% 2 6% 3 3 4 3 5% 6% 47%	2200
November	1st to 10th	Day	12% 5% 2 4 3 3 4 4 4 7% 52%	1856
	11th to 20th	Day	15% 6% 1 4 3 3 4 4 5% 6% 48%	1890
	21st to end	Day	15% 7% 2 6% 4 5% 3 3 5% 5% 46%	1689
December	1st to 10th	Day	13% 7% 3 6% 4 4 4 3 6% 6% 44%	2680
	11th to 20th	Day	20% 9% 2 4 3 3 4 3 4 7% 40%	3070
	21st to end	Day	15% 7% 3 6% 5% 5% 5% 4 5% 7% 37%	4048
January	1st to 10th	Night	11% 8% 3 6% 4 4 4 3 5% 7% 43%	8233
	11th to 20th	Night	15% 8% 2 5% 3 3 3 3 4 5% 49%	7878
	21st to end	Night	15% 7% 2 5% 4 3 3 3 5% 6% 47%	8401
February	1st to 10th	Night	16% 8% 2 7% 5% 4 4 3 5% 6% 40%	2730
	11th to 20th	Night	17% 8% 3 6% 3 4 4 4 5% 5% 41%	2564
	21st to end	Night	15% 8% 3 6% 4 5% 5% 3 4 6% 41%	2076
March	1st to 10th	Night	17% 8% 2 5% 4 3 3 3 3 6% 46%	5288
	11th to 20th	Night	11% 7% 2 5% 3 3 3 4 4 6% 52%	5090
	21st to end	Night	14% 7% 3 6% 4 4 4 3 5% 6% 44%	5366
April	1st to 10th	Night	17% 8% 2 6% 5% 3 3 3 5% 8% 39%	2100
	11th to 20th	Night	15% 5% 2 6% 5% 3 4 4 6% 8% 42%	2075
	21st to end	Night	18% 6% 3 4 3 3 4 3 6% 7% 44%	2100
May	1st to 10th	Night	21% 7% 2 6% 5% 4 4 3 5% 8% 33%	5421
	11th to 20th	Night	21% 8% 2 6% 3 4 3 3 5% 8% 35%	4639
	21st to end	Night	25% 7% 2 6% 4 3 4 3 5% 7% 35%	5108
June	1st to 10th	Night	11% 6% 2 6% 4 5% 4 4 5% 9% 45%	1680
	11th to 20th	Night	13% 6% 1 7% 4 5% 5% 4 7% 8% 40%	1680
	21st to end	Night	11% 5% 2 5% 5% 5% 5% 5% 7% 10% 42%	1680
July	1st to 10th	Night	8% 5% 2 7% 6% 5% 6% 5% 7% 10% 38%	3598
	11th to 20th	Night	11% 8% 3 9% 6% 6% 6% 5% 8% 10% 29%	3597
	21st to end	Night	10% 7% 2 6% 4 5% 4 4 6% 8% 43%	4283
August	1st to 10th	Night	19% 5% 2 6% 4 4 6% 3 6% 9% 35%	2915
	11th to 20th	Night	13% 7% 3 7% 4 5% 5% 3 6% 8% 40%	3071
	21st to end	Night	12% 5% 2 6% 4 4 4 4 6% 8% 47%	3586
September	1st to 10th	Night	14% 7% 1 6% 3 3 4 3 4 6% 48%	2000
	11th to 20th	Night	12% 6% 2 5% 4 3 4 2 4 7% 52%	2000
	21st to end	Night	21% 7% 2 6% 4 4 4 3 4 7% 39%	2260
October	1st to 10th	Night	19% 6% 2 6% 4 4 3 3 5% 5% 45%	2400
	11th to 20th	Night	16% 5% 2 4 3 3 3 3 4 6% 51%	2400
	21st to end	Night	17% 5% 2 4 2 3 4 3 5% 6% 50%	2640
November	1st to 10th	Night	11% 4 2 5% 4 3 4 3 5% 6% 53%	2662
	11th to 20th	Night	15% 6% 2 5% 4 3 3 2 5% 6% 47%	2730
	21st to end	Night	13% 6% 2 5% 5% 4 4 3 6% 7% 46%	2929
December	1st to 10th	Night	11% 7% 2 5% 5% 4 4 3 5% 7% 47%	4720
	11th to 20th	Night	21% 6% 2 5% 4 4 4 3 5% 7% 40%	5345
	21st to end	Night	18% 8% 2 6% 5% 4 5% 4 6% 7% 36%	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	39% 4 10% 26% 18% 3	4662
	11th to 20th	Day	43% 3 7% 20% 18% 7%	5078
	21st to end	Day	43% 6% 11% 26% 12% 2	5780
February	1st to 10th	Day	43% 5% 13% 25% 12% 2	1890
	11th to 20th	Day	45% 5% 11% 24% 14% 2	1951
	21st to end	Day	47% 4 10% 22% 13% 4	1730
March	1st to 10th	Day	39% 5% 9% 24% 17% 6%	4767
	11th to 20th	Day	37% 5% 11% 27% 15% 6%	5090
	21st to end	Day	43% 5% 9% 18% 19% 5%	5807
April	1st to 10th	Day	43% 6% 11% 19% 16% 5%	2520
	11th to 20th	Day	38% 7% 13% 22% 16% 5%	2494
	21st to end	Day	41% 6% 10% 22% 18% 4	2520
May	1st to 10th	Day	47% 7% 11% 20% 14% 1	7519
	11th to 20th	Day	44% 7% 11% 25% 12% 1	8225
	21st to end	Day	46% 7% 10% 21% 16% 1	9061
June	1st to 10th	Day	37% 9% 13% 22% 17% 2	2940
	11th to 20th	Day	40% 9% 13% 23% 12% 3	2940
	21st to end	Day	35% 9% 15% 24% 16% 1	2940
July	1st to 10th	Day	35% 11% 15% 20% 16% 3	6290
	11th to 20th	Day	43% 12% 16% 20% 8% 1	6285
	21st to end	Day	37% 9% 11% 22% 21% 1	6376
August	1st to 10th	Day	46% 9% 13% 23% 9%	4221
	11th to 20th	Day	36% 9% 12% 28% 14% 1	3983
	21st to end	Day	32% 6% 12% 28% 19% 2	4312
September	1st to 10th	Day	39% 6% 11% 20% 20% 4	2400
	11th to 20th	Day	34% 5% 10% 26% 21% 4	2400
	21st to end	Day	46% 7% 9% 18% 18% 2	2135
October	1st to 10th	Day	36% 5% 8% 19% 28% 5%	3260
	11th to 20th	Day	27% 5% 11% 25% 23% 9%	3240
	21st to end	Day	24% 3 12% 29% 28% 4	3538
November	1st to 10th	Day	32% 5% 13% 24% 21% 4	1856
	11th to 20th	Day	37% 5% 11% 24% 21% 3	1890
	21st to end	Day	41% 4 11% 29% 12% 2	1689
December	1st to 10th	Day	40% 5% 16% 25% 11% 3	2680
	11th to 20th	Day	44% 4 13% 29% 9% 1	3066
	21st to end	Day	44% 6% 14% 19% 14% 1	4048
January	1st to 10th	Night	40% 5% 12% 25% 15% 3	8234
	11th to 20th	Night	38% 4 9% 22% 20% 7%	7878
	21st to end	Night	38% 4 8% 29% 19% 2	8401
February	1st to 10th	Night	44% 5% 13% 24% 13% 2	2730
	11th to 20th	Night	44% 4 10% 21% 18% 3	2566
	21st to end	Night	44% 5% 10% 21% 16% 4	2076
March	1st to 10th	Night	41% 5% 8% 25% 12% 9%	5288
	11th to 20th	Night	33% 6% 12% 29% 14% 6%	5090
	21st to end	Night	41% 5% 8% 19% 24% 3	5366
April	1st to 10th	Night	44% 5% 11% 19% 17% 4	2100
	11th to 20th	Night	38% 6% 12% 20% 19% 4	2075
	21st to end	Night	39% 6% 11% 21% 18% 5%	2100
May	1st to 10th	Night	48% 7% 10% 19% 14% 3	5451
	11th to 20th	Night	47% 7% 11% 24% 11% 1	4640
	21st to end	Night	49% 7% 9% 21% 12% 2	5115
June	1st to 10th	Night	36% 8% 10% 24% 20% 2	1680
	11th to 20th	Night	40% 8% 14% 22% 15% 1	1680
	21st to end	Night	35% 8% 14% 25% 16% 2	1680
July	1st to 10th	Night	40% 10% 15% 17% 14% 3	3560
	11th to 20th	Night	46% 11% 17% 17% 9% 1	3552
	21st to end	Night	36% 8% 13% 23% 20%	4157
August	1st to 10th	Night	45% 8% 17% 20% 9% 1	2904
	11th to 20th	Night	40% 7% 11% 26% 14% 1	3098
	21st to end	Night	34% 7% 11% 30% 17% 2	3586
September	1st to 10th	Night	37% 7% 10% 21% 21% 4	2000
	11th to 20th	Night	33% 5% 10% 24% 24% 4	2000
	21st to end	Night	45% 6% 9% 19% 18% 2	2260
October	1st to 10th	Night	42% 6% 9% 19% 22% 2	3920
	11th to 20th	Night	25% 5% 11% 26% 28% 6%	3899
	21st to end	Night	25% 4 10% 32% 24% 4	4252
November	1st to 10th	Night	31% 5% 12% 25% 22% 5%	2662
	11th to 20th	Night	39% 4 9% 23% 20% 5%	2730
	21st to end	Night	37% 5% 12% 26% 17% 2	2929
December	1st to 10th	Night	38% 5% 13% 30% 14% 1	4720
	11th to 20th	Night	44% 5% 13% 21% 15% 3	5348
	21st to end	Night	45% 7% 12% 19% 17% 1	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	28% 27% 29% 12% 4 1	220
	11th to 20th	Day	30% 29% 27% 12% 1	293
	21st to end	Day	23% 30% 32% 11% 4	363
February	1st to 10th	Day	26% 22% 38% 11% 3 1	330
	11th to 20th	Day	31% 24% 35% 7% 1	429
	21st to end	Day	28% 22% 35% 13% 3	446
March	1st to 10th	Day	23% 24% 31% 18% 4	540
	11th to 20th	Day	24% 23% 34% 14% 5% 1	540
	21st to end	Day	24% 21% 35% 15% 4 2	594
April	1st to 10th	Day	23% 21% 33% 16% 6% 1	540
	11th to 20th	Day	20% 21% 30% 17% 9% 3	532
	21st to end	Day	24% 16% 32% 20% 8% 1	540
May	1st to 10th	Day	25% 17% 27% 20% 9% 2	543
	11th to 20th	Day	22% 13% 29% 24% 11% 3	567
	21st to end	Day	23% 7% 22% 24% 19% 5%	617
June	1st to 10th	Day	14% 9% 31% 25% 15% 6%	570
	11th to 20th	Day	18% 10% 25% 29% 14% 4	570
	21st to end	Day	13% 8% 25% 32% 15% 6%	570
July	1st to 10th	Day	12% 5% 17% 31% 23% 12%	525
	11th to 20th	Day	6% 3 19% 36% 26% 9%	524
	21st to end	Day	11% 5% 24% 33% 21% 6%	576
August	1st to 10th	Day	13% 4 20% 32% 23% 8%	526
	11th to 20th	Day	12% 3 19% 32% 22% 11%	519
	21st to end	Day	10% 5% 22% 31% 22% 10%	583
September	1st to 10th	Day	18% 8% 19% 25% 20% 10%	530
	11th to 20th	Day	15% 4 22% 28% 23% 8%	530
	21st to end	Day	25% 11% 22% 24% 14% 4	530
October	1st to 10th	Day	21% 8% 22% 26% 14% 9%	530
	11th to 20th	Day	19% 14% 27% 24% 13% 3	530
	21st to end	Day	18% 14% 33% 23% 9% 2	583
November	1st to 10th	Day	18% 12% 31% 25% 11% 3	428
	11th to 20th	Day	18% 20% 32% 21% 9%	430
	21st to end	Day	22% 22% 34% 17% 5%	229
December	1st to 10th	Day	24% 24% 31% 16% 3 1	220
	11th to 20th	Day	28% 22% 31% 14% 5%	220
	21st to end	Day	25% 20% 31% 17% 7%	242
January	1st to 10th	Night	19% 17% 42% 19% 3	840
	11th to 20th	Night	24% 17% 33% 24% 3	840
	21st to end	Night	18% 18% 42% 21% 2	924
February	1st to 10th	Night	20% 18% 37% 23% 2	840
	11th to 20th	Night	24% 21% 38% 16% 1	823
	21st to end	Night	21% 20% 39% 18% 2	692
March	1st to 10th	Night	19% 19% 36% 21% 4	840
	11th to 20th	Night	21% 19% 36% 20% 5%	840
	21st to end	Night	21% 15% 39% 21% 4	924
April	1st to 10th	Night	23% 17% 37% 20% 4	840
	11th to 20th	Night	18% 13% 34% 27% 7%	831
	21st to end	Night	21% 12% 32% 28% 7%	840
May	1st to 10th	Night	21% 10% 31% 31% 7%	698
	11th to 20th	Night	20% 9% 30% 34% 8%	414
	21st to end	Night	18% 5% 20% 39% 15% 2	455
June	1st to 10th	Night	12% 4 26% 40% 18%	420
	11th to 20th	Night	15% 5% 23% 42% 15%	420
	21st to end	Night	11% 3 20% 49% 17%	420
July	1st to 10th	Night	12% 3 16% 40% 27% 2	390
	11th to 20th	Night	7% 3 13% 45% 30% 3	388
	21st to end	Night	9% 2 16% 46% 25% 2	591
August	1st to 10th	Night	12% 2 13% 43% 27% 2	597
	11th to 20th	Night	13% 4 15% 38% 29% 2	712
	21st to end	Night	13% 3 16% 39% 25% 4	880
September	1st to 10th	Night	16% 3 20% 35% 23% 4	800
	11th to 20th	Night	13% 4 15% 38% 26% 5%	800
	21st to end	Night	23% 4 19% 33% 19% 2	800
October	1st to 10th	Night	21% 5% 22% 28% 20% 4	800
	11th to 20th	Night	18% 9% 28% 32% 12% 1	800
	21st to end	Night	19% 11% 32% 26% 12%	880
November	1st to 10th	Night	15% 9% 34% 31% 11% 1	820
	11th to 20th	Night	19% 16% 31% 27% 7% 1	840
	21st to end	Night	16% 16% 34% 27% 7%	840
December	1st to 10th	Night	21% 16% 35% 21% 6%	840
	11th to 20th	Night	20% 14% 39% 22% 5%	840
	21st to end	Night	20% 15% 36% 26% 3	924

Page generated at 2026-06-28 02:10:48. Version ac07

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