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 2025-02-25.

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%	108687
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	110001
Transparency	Day	40% 7% 12% 23% 16% 3	112319
	Night	39% 6% 11% 23% 17% 3	114508
Seeing	Day	19% 13% 27% 23% 13% 4	15256
	Night	18% 11% 30% 29% 11% 1	24768

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 6% 4 4 4 4 5% 6% 48%	3597
	11th to 20th	Day	13% 9% 3 10% 5% 4 4 2 4 4 42%	3900
	21st to end	Day	16% 8% 3 6% 4 4 4 3 5% 6% 41%	4466
February	1st to 10th	Day	14% 9% 2 6% 4 4 4 3 6% 7% 39%	1800
	11th to 20th	Day	17% 8% 2 5% 5% 5% 4 3 5% 6% 40%	1847
	21st to end	Day	17% 11% 3 7% 3 3 3 3 4 5% 40%	1610
March	1st to 10th	Day	23% 6% 2 5% 4 4 4 3 5% 6% 40%	3247
	11th to 20th	Day	10% 6% 3 6% 5% 4 5% 4 6% 7% 46%	3480
	21st to end	Day	21% 8% 2 5% 4 3 3 2 4 4 43%	3962
April	1st to 10th	Day	15% 7% 2 6% 5% 4 4 5% 5% 7% 40%	2280
	11th to 20th	Day	14% 6% 2 5% 4 4 4 4 5% 7% 44%	2254
	21st to end	Day	17% 6% 2 5% 4 4 4 4 5% 7% 41%	2280
May	1st to 10th	Day	28% 7% 3 6% 4 4 4 3 5% 6% 30%	4011
	11th to 20th	Day	24% 8% 3 7% 5% 5% 4 4 5% 7% 28%	4398
	21st to end	Day	11% 5% 2 5% 4 4 4 4 7% 9% 44%	4823
June	1st to 10th	Day	12% 6% 2 6% 5% 4 5% 4 8% 10% 38%	2660
	11th to 20th	Day	12% 6% 2 7% 5% 5% 6% 4 7% 9% 39%	2660
	21st to end	Day	10% 4 2 5% 4 5% 5% 5% 7% 10% 43%	2660
July	1st to 10th	Day	6% 4 2 6% 5% 5% 6% 5% 9% 11% 40%	4440
	11th to 20th	Day	9% 6% 2 5% 5% 5% 6% 5% 7% 11% 38%	4440
	21st to end	Day	10% 7% 3 8% 6% 6% 6% 5% 8% 8% 34%	4564
August	1st to 10th	Day	18% 5% 2 7% 4 5% 6% 5% 7% 8% 33%	4104
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 8% 9% 40%	3821
	21st to end	Day	11% 5% 1 5% 4 4 4 4 6% 7% 49%	4180
September	1st to 10th	Day	15% 6% 2 6% 4 4 4 3 5% 6% 45%	2280
	11th to 20th	Day	12% 5% 2 5% 3 3 3 3 5% 8% 50%	2280
	21st to end	Day	20% 7% 3 6% 4 3 4 3 5% 7% 36%	2028
October	1st to 10th	Day	17% 6% 2 6% 4 3 4 3 5% 6% 44%	1900
	11th to 20th	Day	17% 5% 2 5% 3 3 4 3 5% 6% 48%	1900
	21st to end	Day	16% 6% 2 6% 3 3 4 3 5% 5% 47%	2090
November	1st to 10th	Day	12% 5% 2 4 3 3 4 4 4 7% 51%	1766
	11th to 20th	Day	15% 6% 1 5% 3 3 4 4 5% 6% 48%	1800
	21st to end	Day	15% 7% 2 6% 4 5% 3 3 5% 5% 46%	1609
December	1st to 10th	Day	13% 6% 3 6% 4 5% 4 3 5% 6% 45%	2600
	11th to 20th	Day	20% 9% 2 5% 3 3 4 3 4 7% 40%	2990
	21st to end	Day	15% 7% 3 6% 5% 5% 5% 4 5% 7% 37%	3960
January	1st to 10th	Night	13% 7% 2 6% 4 4 4 3 5% 7% 47%	6349
	11th to 20th	Night	14% 7% 2 5% 4 3 4 3 4 5% 49%	6056
	21st to end	Night	16% 7% 3 6% 4 3 3 3 4 5% 46%	6490
February	1st to 10th	Night	16% 8% 3 7% 5% 4 3 3 5% 6% 40%	2600
	11th to 20th	Night	17% 8% 3 6% 3 4 4 4 5% 5% 42%	2439
	21st to end	Night	16% 7% 3 6% 4 5% 5% 3 4 6% 41%	1939
March	1st to 10th	Night	21% 9% 3 6% 4 3 3 3 4 5% 39%	3588
	11th to 20th	Night	11% 6% 2 5% 4 4 4 4 4 6% 51%	3480
	21st to end	Night	15% 9% 3 6% 4 3 3 2 3 5% 47%	3669
April	1st to 10th	Night	16% 8% 2 5% 5% 3 3 3 5% 8% 39%	1900
	11th to 20th	Night	15% 5% 2 5% 4 3 4 4 6% 8% 43%	1875
	21st to end	Night	18% 7% 3 5% 3 3 4 3 6% 6% 43%	1900
May	1st to 10th	Night	25% 8% 2 6% 5% 3 4 3 5% 8% 31%	2911
	11th to 20th	Night	25% 11% 3 7% 4 4 4 3 5% 6% 28%	2495
	21st to end	Night	12% 6% 2 5% 3 4 5% 4 6% 10% 43%	2732
June	1st to 10th	Night	12% 6% 1 6% 4 5% 4 4 5% 9% 45%	1520
	11th to 20th	Night	12% 6% 1 7% 4 5% 5% 4 7% 9% 41%	1520
	21st to end	Night	10% 4 2 5% 5% 5% 5% 5% 7% 10% 43%	1520
July	1st to 10th	Night	7% 5% 2 7% 7% 5% 6% 5% 7% 10% 39%	2520
	11th to 20th	Night	9% 6% 3 6% 5% 5% 6% 5% 8% 11% 37%	2520
	21st to end	Night	12% 8% 3 7% 5% 5% 5% 4 6% 7% 38%	2985
August	1st to 10th	Night	20% 5% 2 6% 4 4 6% 3 6% 9% 35%	2825
	11th to 20th	Night	13% 7% 3 7% 4 5% 5% 3 5% 8% 41%	2975
	21st to end	Night	12% 5% 2 6% 4 4 4 4 6% 8% 47%	3476
September	1st to 10th	Night	14% 7% 1 6% 4 3 4 3 4 6% 47%	1900
	11th to 20th	Night	12% 6% 2 4 3 3 4 2 4 7% 53%	1900
	21st to end	Night	21% 6% 2 5% 4 4 4 3 4 6% 40%	2147
October	1st to 10th	Night	20% 7% 2 6% 4 4 3 3 5% 5% 43%	2280
	11th to 20th	Night	16% 5% 2 4 3 3 3 3 4 6% 51%	2280
	21st to end	Night	17% 5% 2 4 2 3 4 3 5% 6% 49%	2508
November	1st to 10th	Night	11% 4 2 5% 4 3 4 3 5% 5% 54%	2532
	11th to 20th	Night	16% 6% 2 5% 4 3 3 2 5% 6% 47%	2600
	21st to end	Night	13% 5% 2 5% 5% 4 4 3 6% 7% 46%	2789
December	1st to 10th	Night	11% 7% 2 5% 5% 4 4 3 5% 7% 47%	4580
	11th to 20th	Night	22% 6% 2 5% 4 4 4 3 5% 7% 40%	5205
	21st to end	Night	18% 8% 2 6% 5% 4 5% 4 6% 7% 36%	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	36% 4 10% 25% 21% 3	3598
	11th to 20th	Day	46% 4 8% 20% 16% 6%	3900
	21st to end	Day	44% 6% 11% 24% 14% 2	4466
February	1st to 10th	Day	44% 5% 13% 25% 11% 2	1800
	11th to 20th	Day	44% 5% 11% 24% 14% 3	1856
	21st to end	Day	47% 4 10% 21% 13% 4	1610
March	1st to 10th	Day	45% 5% 11% 27% 11% 2	3247
	11th to 20th	Day	34% 5% 11% 28% 18% 4	3480
	21st to end	Day	45% 5% 9% 20% 18% 3	3962
April	1st to 10th	Day	42% 6% 12% 19% 16% 5%	2280
	11th to 20th	Day	38% 7% 12% 22% 16% 5%	2254
	21st to end	Day	41% 6% 11% 20% 18% 4	2280
May	1st to 10th	Day	53% 7% 10% 19% 10% 2	4046
	11th to 20th	Day	54% 8% 13% 17% 7% 1	4402
	21st to end	Day	33% 8% 14% 25% 17% 2	4837
June	1st to 10th	Day	38% 9% 13% 23% 15% 2	2660
	11th to 20th	Day	40% 9% 13% 24% 12% 3	2660
	21st to end	Day	34% 9% 16% 24% 16% 1	2660
July	1st to 10th	Day	35% 11% 17% 20% 14% 4	4370
	11th to 20th	Day	36% 10% 16% 25% 11% 1	4365
	21st to end	Day	43% 9% 11% 18% 16% 1	4418
August	1st to 10th	Day	46% 9% 13% 23% 9%	4091
	11th to 20th	Day	36% 8% 12% 28% 15% 1	3860
	21st to end	Day	33% 6% 12% 28% 18% 2	4180
September	1st to 10th	Day	40% 6% 11% 19% 20% 4	2280
	11th to 20th	Day	34% 5% 10% 26% 22% 4	2280
	21st to end	Day	45% 6% 9% 19% 19% 2	2028
October	1st to 10th	Day	37% 5% 8% 18% 28% 5%	3160
	11th to 20th	Day	26% 5% 11% 25% 23% 9%	3140
	21st to end	Day	25% 3 12% 29% 28% 4	3428
November	1st to 10th	Day	33% 5% 13% 24% 21% 4	1766
	11th to 20th	Day	36% 5% 11% 25% 20% 3	1800
	21st to end	Day	40% 4 12% 30% 12% 2	1609
December	1st to 10th	Day	40% 5% 16% 25% 11% 3	2600
	11th to 20th	Day	45% 4 13% 29% 9% 1	2986
	21st to end	Day	44% 7% 15% 19% 14% 1	3960
January	1st to 10th	Night	37% 4 10% 26% 19% 4	6349
	11th to 20th	Night	37% 4 11% 24% 18% 6%	6056
	21st to end	Night	41% 4 9% 27% 18% 2	6490
February	1st to 10th	Night	44% 5% 13% 24% 12% 1	2600
	11th to 20th	Night	44% 4 10% 21% 19% 3	2441
	21st to end	Night	45% 5% 10% 20% 16% 4	1939
March	1st to 10th	Night	47% 5% 9% 25% 12% 1	3588
	11th to 20th	Night	33% 6% 11% 31% 16% 3	3480
	21st to end	Night	41% 5% 7% 20% 22% 5%	3669
April	1st to 10th	Night	43% 5% 11% 20% 17% 4	1900
	11th to 20th	Night	38% 6% 12% 20% 19% 5%	1875
	21st to end	Night	40% 6% 11% 21% 18% 5%	1900
May	1st to 10th	Night	51% 8% 8% 18% 12% 2	2941
	11th to 20th	Night	55% 8% 11% 13% 11% 1	2496
	21st to end	Night	35% 11% 14% 23% 13% 4	2739
June	1st to 10th	Night	36% 9% 11% 25% 18% 2	1520
	11th to 20th	Night	39% 8% 14% 23% 15% 1	1520
	21st to end	Night	34% 8% 14% 26% 16% 2	1520
July	1st to 10th	Night	38% 11% 17% 17% 12% 4	2480
	11th to 20th	Night	38% 10% 18% 21% 12% 1	2472
	21st to end	Night	42% 8% 14% 19% 16% 1	2890
August	1st to 10th	Night	45% 8% 17% 20% 8% 1	2814
	11th to 20th	Night	40% 7% 12% 26% 14% 1	3002
	21st to end	Night	34% 7% 11% 30% 17% 2	3476
September	1st to 10th	Night	38% 7% 11% 20% 20% 4	1900
	11th to 20th	Night	32% 4 10% 24% 25% 4	1900
	21st to end	Night	44% 5% 9% 20% 19% 3	2147
October	1st to 10th	Night	43% 6% 9% 19% 21% 2	3800
	11th to 20th	Night	24% 5% 11% 26% 28% 6%	3779
	21st to end	Night	25% 4 11% 32% 24% 4	4120
November	1st to 10th	Night	32% 5% 12% 25% 22% 5%	2532
	11th to 20th	Night	39% 4 9% 24% 19% 5%	2600
	21st to end	Night	37% 5% 13% 26% 17% 2	2789
December	1st to 10th	Night	37% 5% 12% 30% 14% 2	4580
	11th to 20th	Night	44% 5% 13% 21% 14% 3	5208
	21st to end	Night	45% 7% 12% 18% 17% 1	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	29% 27% 28% 13% 3 1	200
	11th to 20th	Day	29% 28% 29% 13% 1	266
	21st to end	Day	21% 29% 34% 12% 5%	330
February	1st to 10th	Day	27% 21% 38% 10% 3 1	300
	11th to 20th	Day	30% 26% 35% 7% 1	394
	21st to end	Day	28% 21% 34% 14% 3	398
March	1st to 10th	Day	20% 24% 32% 20% 4	460
	11th to 20th	Day	22% 23% 35% 14% 5% 1	460
	21st to end	Day	23% 20% 33% 17% 5% 2	506
April	1st to 10th	Day	21% 21% 35% 17% 6% 1	460
	11th to 20th	Day	18% 20% 30% 19% 10% 3	452
	21st to end	Day	24% 15% 32% 20% 8% 1	460
May	1st to 10th	Day	26% 15% 26% 21% 10% 2	463
	11th to 20th	Day	21% 12% 28% 24% 11% 3	487
	21st to end	Day	18% 6% 22% 27% 22% 5%	529
June	1st to 10th	Day	14% 8% 31% 24% 16% 7%	490
	11th to 20th	Day	15% 9% 24% 31% 15% 5%	490
	21st to end	Day	12% 7% 28% 32% 15% 6%	490
July	1st to 10th	Day	12% 4 17% 31% 24% 12%	485
	11th to 20th	Day	5% 3 18% 37% 27% 10%	484
	21st to end	Day	12% 4 24% 32% 21% 6%	532
August	1st to 10th	Day	13% 4 20% 32% 24% 8%	486
	11th to 20th	Day	11% 4 19% 33% 23% 11%	479
	21st to end	Day	10% 5% 20% 32% 22% 11%	539
September	1st to 10th	Day	19% 7% 18% 24% 21% 11%	490
	11th to 20th	Day	15% 3 22% 27% 24% 9%	490
	21st to end	Day	26% 10% 22% 23% 14% 4	490
October	1st to 10th	Day	22% 8% 23% 26% 14% 8%	490
	11th to 20th	Day	17% 13% 27% 26% 14% 3	490
	21st to end	Day	18% 13% 33% 24% 10% 2	539
November	1st to 10th	Day	17% 11% 31% 26% 12% 3	398
	11th to 20th	Day	16% 20% 33% 22% 10%	400
	21st to end	Day	21% 22% 33% 18% 6%	209
December	1st to 10th	Day	23% 23% 33% 17% 3 2	200
	11th to 20th	Day	28% 22% 31% 15% 6%	200
	21st to end	Day	23% 20% 32% 18% 7%	220
January	1st to 10th	Night	19% 17% 42% 18% 3	800
	11th to 20th	Night	23% 16% 33% 25% 3	800
	21st to end	Night	17% 18% 42% 21% 2	880
February	1st to 10th	Night	20% 18% 37% 22% 2	800
	11th to 20th	Night	24% 21% 38% 16% 1	783
	21st to end	Night	21% 20% 38% 18% 2	647
March	1st to 10th	Night	18% 19% 37% 22% 4	760
	11th to 20th	Night	20% 20% 36% 19% 5% 1	760
	21st to end	Night	21% 14% 38% 22% 5%	836
April	1st to 10th	Night	21% 17% 38% 20% 4	760
	11th to 20th	Night	18% 13% 34% 28% 7%	751
	21st to end	Night	22% 11% 33% 27% 8%	760
May	1st to 10th	Night	22% 9% 29% 31% 8%	632
	11th to 20th	Night	20% 8% 30% 33% 8%	374
	21st to end	Night	16% 5% 20% 41% 16% 2	411
June	1st to 10th	Night	13% 3 25% 40% 18% 1	380
	11th to 20th	Night	13% 4 23% 44% 16% 1	380
	21st to end	Night	11% 2 20% 51% 15%	380
July	1st to 10th	Night	11% 2 16% 40% 28% 2	370
	11th to 20th	Night	6% 3 13% 45% 30% 3	368
	21st to end	Night	9% 2 16% 46% 24% 2	561
August	1st to 10th	Night	12% 2 14% 43% 27% 2	567
	11th to 20th	Night	13% 4 15% 38% 28% 2	676
	21st to end	Night	13% 3 15% 39% 26% 4	836
September	1st to 10th	Night	17% 3 19% 34% 23% 4	760
	11th to 20th	Night	13% 4 14% 37% 27% 5%	760
	21st to end	Night	23% 4 19% 33% 19% 2	760
October	1st to 10th	Night	21% 6% 22% 29% 19% 4	760
	11th to 20th	Night	17% 9% 28% 32% 13% 1	760
	21st to end	Night	20% 10% 32% 26% 13%	836
November	1st to 10th	Night	14% 9% 34% 32% 11% 1	780
	11th to 20th	Night	19% 15% 31% 28% 7% 1	800
	21st to end	Night	16% 16% 34% 27% 7%	800
December	1st to 10th	Night	22% 16% 35% 21% 6% 1	800
	11th to 20th	Night	20% 13% 40% 23% 5%	800
	21st to end	Night	20% 15% 36% 26% 3	880

Page generated at 2025-02-22 06:51:38. Version ac07

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