Kinzua Bridge State Park Visitor's Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kinzua Bridge State Park Visitor's Center clear sky chart from 2005-11-06 to 2025-04-26.

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	16% 12% 5% 10% 6% 5% 4 3 5% 6% 28%	113758
	Night	15% 14% 5% 12% 6% 4 4 3 5% 5% 27%	114839
Transparency	Day	55% 5% 11% 19% 9% 1	117398
	Night	57% 5% 11% 17% 9% 1	119362
Seeing	Day	27% 18% 28% 16% 8% 3	15167
	Night	25% 18% 27% 21% 9% 1	24770

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% 19% 10% 22% 9% 4 3 2 3 3 12%	3597
	11th to 20th	Day	9% 20% 10% 25% 8% 7% 2 2 3 3 11%	4023
	21st to end	Day	18% 15% 8% 14% 9% 5% 5% 3 4 4 15%	4466
February	1st to 10th	Day	14% 21% 7% 14% 9% 6% 4 2 4 3 18%	1800
	11th to 20th	Day	13% 16% 8% 16% 8% 5% 4 3 5% 4 19%	1753
	21st to end	Day	17% 18% 3 13% 7% 4 4 3 4 5% 23%	1590
March	1st to 10th	Day	16% 12% 9% 10% 5% 4 3 3 3 5% 30%	4932
	11th to 20th	Day	12% 15% 7% 10% 4 3 3 3 4 6% 33%	4980
	21st to end	Day	16% 13% 5% 12% 6% 4 4 3 4 4 28%	5465
April	1st to 10th	Day	17% 17% 4 9% 4 4 4 3 5% 6% 27%	2387
	11th to 20th	Day	17% 16% 3 7% 4 4 4 3 4 5% 32%	2374
	21st to end	Day	21% 11% 3 7% 5% 4 3 3 4 5% 33%	2495
May	1st to 10th	Day	26% 9% 3 7% 5% 4 4 3 4 5% 29%	4108
	11th to 20th	Day	20% 11% 3 9% 6% 5% 5% 4 5% 7% 25%	4324
	21st to end	Day	13% 7% 2 6% 5% 5% 4 4 5% 7% 41%	4837
June	1st to 10th	Day	17% 9% 3 7% 6% 5% 5% 3 6% 8% 32%	2660
	11th to 20th	Day	15% 7% 3 7% 6% 6% 5% 4 8% 8% 32%	2660
	21st to end	Day	16% 6% 3 7% 5% 4 4 5% 7% 8% 35%	2660
July	1st to 10th	Day	10% 6% 2 7% 5% 6% 6% 5% 7% 10% 35%	4440
	11th to 20th	Day	11% 7% 3 7% 5% 5% 6% 5% 8% 9% 35%	4390
	21st to end	Day	11% 7% 3 7% 6% 5% 6% 5% 6% 8% 36%	4466
August	1st to 10th	Day	19% 8% 3 8% 5% 5% 5% 4 6% 9% 28%	4104
	11th to 20th	Day	15% 7% 2 8% 6% 6% 7% 5% 8% 9% 27%	4044
	21st to end	Day	14% 7% 2 6% 5% 4 5% 4 7% 9% 36%	4226
September	1st to 10th	Day	19% 7% 2 6% 4 4 5% 3 5% 5% 40%	2280
	11th to 20th	Day	15% 6% 3 7% 4 5% 4 4 4 7% 40%	2218
	21st to end	Day	23% 8% 3 7% 5% 3 5% 3 5% 6% 31%	2019
October	1st to 10th	Day	19% 8% 3 7% 4 4 5% 4 6% 6% 33%	1900
	11th to 20th	Day	21% 11% 4 8% 5% 3 4 3 4 5% 31%	1900
	21st to end	Day	22% 15% 3 8% 5% 5% 5% 4 4 5% 25%	2090
November	1st to 10th	Day	14% 14% 4 7% 5% 3 4 4 6% 6% 34%	1824
	11th to 20th	Day	15% 19% 6% 9% 5% 3 3 4 5% 6% 24%	1600
	21st to end	Day	18% 23% 7% 10% 6% 3 4 3 4 4 19%	1600
December	1st to 10th	Day	17% 23% 10% 21% 6% 3 3 2 3 3 8%	2600
	11th to 20th	Day	18% 19% 8% 14% 9% 4 3 2 4 3 17%	2986
	21st to end	Day	18% 25% 9% 12% 5% 4 3 3 3 4 13%	3960
January	1st to 10th	Night	12% 17% 9% 27% 10% 4 3 2 3 3 9%	6349
	11th to 20th	Night	9% 17% 9% 25% 10% 6% 4 3 4 4 9%	5859
	21st to end	Night	16% 17% 7% 16% 10% 7% 5% 3 3 3 13%	6490
February	1st to 10th	Night	14% 19% 6% 14% 9% 6% 4 3 4 3 18%	2600
	11th to 20th	Night	12% 14% 6% 16% 9% 6% 6% 3 5% 5% 17%	2533
	21st to end	Night	18% 14% 5% 15% 8% 5% 4 3 4 4 22%	2033
March	1st to 10th	Night	15% 16% 6% 11% 9% 5% 3 2 4 4 26%	4908
	11th to 20th	Night	13% 13% 7% 9% 4 3 3 3 5% 6% 35%	4979
	21st to end	Night	12% 14% 5% 11% 5% 5% 4 3 4 6% 31%	5467
April	1st to 10th	Night	17% 15% 4 9% 5% 4 4 3 5% 5% 27%	2011
	11th to 20th	Night	18% 14% 3 6% 4 3 3 3 6% 5% 34%	1975
	21st to end	Night	15% 11% 4 8% 5% 4 4 3 5% 8% 33%	1816
May	1st to 10th	Night	26% 11% 3 6% 4 4 4 3 4 6% 30%	2833
	11th to 20th	Night	21% 12% 3 6% 5% 3 5% 3 4 6% 32%	2566
	21st to end	Night	14% 8% 2 6% 4 4 4 3 7% 8% 40%	2738
June	1st to 10th	Night	13% 7% 3 6% 5% 5% 4 4 7% 9% 37%	1520
	11th to 20th	Night	11% 7% 3 6% 5% 5% 4 4 6% 9% 39%	1520
	21st to end	Night	15% 8% 2 6% 3 5% 4 3 6% 7% 42%	1520
July	1st to 10th	Night	12% 9% 2 9% 4 4 4 4 5% 7% 39%	2520
	11th to 20th	Night	10% 7% 2 6% 5% 4 5% 5% 6% 9% 42%	2567
	21st to end	Night	13% 6% 2 6% 4 4 5% 4 6% 8% 41%	3087
August	1st to 10th	Night	17% 8% 2 7% 5% 4 5% 4 6% 8% 35%	2825
	11th to 20th	Night	17% 9% 3 6% 4 5% 5% 3 5% 6% 38%	2785
	21st to end	Night	11% 7% 2 6% 4 4 5% 4 5% 9% 44%	3398
September	1st to 10th	Night	14% 7% 3 7% 4 4 4 3 5% 7% 43%	1900
	11th to 20th	Night	13% 7% 2 5% 3 4 4 3 6% 6% 47%	1959
	21st to end	Night	20% 8% 2 7% 4 4 4 4 5% 6% 34%	2161
October	1st to 10th	Night	17% 8% 3 7% 4 4 4 3 4 6% 40%	2280
	11th to 20th	Night	19% 11% 3 6% 5% 4 4 3 5% 6% 33%	2280
	21st to end	Night	23% 14% 4 7% 4 3 4 3 5% 5% 28%	2508
November	1st to 10th	Night	11% 15% 3 8% 4 4 3 3 5% 6% 38%	2468
	11th to 20th	Night	15% 19% 5% 10% 5% 4 4 4 5% 5% 24%	2800
	21st to end	Night	15% 20% 6% 12% 6% 4 4 4 4 5% 20%	2800
December	1st to 10th	Night	13% 19% 10% 20% 8% 5% 5% 3 4 4 10%	4580
	11th to 20th	Night	18% 18% 9% 15% 5% 4 3 2 3 4 18%	5208
	21st to end	Night	18% 20% 10% 14% 7% 4 3 3 4 4 13%	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	78% 3 5% 9% 4	3598
	11th to 20th	Day	81% 2 5% 8% 3	4057
	21st to end	Day	72% 3 9% 11% 4 1	4466
February	1st to 10th	Day	71% 3 9% 11% 5%	1800
	11th to 20th	Day	67% 4 8% 15% 6%	1762
	21st to end	Day	63% 3 10% 16% 5% 2	1590
March	1st to 10th	Day	56% 4 11% 20% 8%	4935
	11th to 20th	Day	53% 4 15% 19% 7% 2	4980
	21st to end	Day	58% 4 6% 17% 12% 2	5465
April	1st to 10th	Day	58% 4 10% 17% 11% 1	2387
	11th to 20th	Day	53% 6% 10% 18% 12% 1	2374
	21st to end	Day	53% 4 10% 19% 12% 2	2495
May	1st to 10th	Day	56% 5% 9% 21% 8% 1	4120
	11th to 20th	Day	56% 7% 12% 19% 6% 1	4328
	21st to end	Day	41% 6% 13% 24% 14% 1	4837
June	1st to 10th	Day	48% 6% 12% 20% 12% 1	2660
	11th to 20th	Day	47% 7% 14% 20% 11% 1	2660
	21st to end	Day	44% 7% 13% 24% 11%	2660
July	1st to 10th	Day	42% 7% 13% 24% 12% 2	4370
	11th to 20th	Day	41% 8% 13% 23% 14%	4315
	21st to end	Day	43% 7% 13% 25% 11% 1	4324
August	1st to 10th	Day	51% 7% 13% 21% 8%	4091
	11th to 20th	Day	48% 8% 16% 23% 5%	4083
	21st to end	Day	41% 6% 12% 29% 10% 1	4226
September	1st to 10th	Day	46% 5% 10% 22% 16% 1	2280
	11th to 20th	Day	43% 5% 11% 24% 16% 2	2218
	21st to end	Day	53% 5% 10% 19% 12%	2019
October	1st to 10th	Day	43% 6% 11% 22% 17% 1	3160
	11th to 20th	Day	46% 4 13% 18% 14% 4	3140
	21st to end	Day	47% 4 13% 24% 10% 1	3428
November	1st to 10th	Day	48% 6% 12% 19% 13% 2	1824
	11th to 20th	Day	60% 4 11% 16% 7% 2	1600
	21st to end	Day	68% 4 10% 12% 5% 1	1600
December	1st to 10th	Day	82% 2 8% 7% 2	2600
	11th to 20th	Day	71% 4 9% 13% 3	2986
	21st to end	Day	75% 4 8% 9% 4	3960
January	1st to 10th	Night	79% 3 7% 8% 3	6349
	11th to 20th	Night	78% 3 9% 6% 2	5900
	21st to end	Night	76% 3 7% 9% 5% 1	6490
February	1st to 10th	Night	69% 4 9% 12% 5%	2600
	11th to 20th	Night	68% 4 8% 13% 5% 1	2535
	21st to end	Night	65% 4 9% 13% 8% 1	2033
March	1st to 10th	Night	61% 4 12% 16% 6% 1	4918
	11th to 20th	Night	50% 5% 16% 20% 6% 3	4980
	21st to end	Night	53% 5% 9% 17% 15% 2	5467
April	1st to 10th	Night	58% 5% 9% 16% 11% 1	2011
	11th to 20th	Night	51% 5% 11% 19% 11% 2	1975
	21st to end	Night	49% 5% 12% 20% 12% 2	1816
May	1st to 10th	Night	55% 5% 11% 19% 8% 2	2840
	11th to 20th	Night	53% 7% 13% 19% 7% 1	2567
	21st to end	Night	40% 8% 12% 21% 15% 4	2739
June	1st to 10th	Night	43% 6% 12% 24% 13% 1	1520
	11th to 20th	Night	40% 8% 15% 23% 13% 2	1520
	21st to end	Night	40% 6% 13% 27% 14%	1520
July	1st to 10th	Night	45% 5% 11% 21% 17% 1	2480
	11th to 20th	Night	36% 6% 17% 26% 15% 1	2519
	21st to end	Night	40% 7% 12% 24% 17% 1	2988
August	1st to 10th	Night	47% 7% 14% 24% 8% 1	2814
	11th to 20th	Night	45% 6% 15% 27% 8%	2812
	21st to end	Night	36% 6% 14% 33% 10% 1	3398
September	1st to 10th	Night	40% 5% 12% 25% 15% 3	1900
	11th to 20th	Night	37% 5% 12% 26% 18% 2	1959
	21st to end	Night	50% 6% 12% 19% 12% 1	2161
October	1st to 10th	Night	44% 5% 9% 22% 19% 1	3800
	11th to 20th	Night	44% 5% 13% 18% 14% 7%	3779
	21st to end	Night	43% 4 16% 24% 12% 1	4120
November	1st to 10th	Night	46% 5% 12% 21% 14% 3	2468
	11th to 20th	Night	61% 5% 10% 15% 8% 2	2800
	21st to end	Night	65% 4 11% 16% 3 1	2800
December	1st to 10th	Night	76% 4 11% 7% 2	4580
	11th to 20th	Night	71% 3 9% 14% 4	5208
	21st to end	Night	74% 4 8% 11% 3	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	36% 26% 28% 6% 4 1	200
	11th to 20th	Day	38% 30% 25% 5% 2	299
	21st to end	Day	37% 25% 30% 7% 1	330
February	1st to 10th	Day	38% 30% 27% 5%	300
	11th to 20th	Day	42% 27% 27% 3 1	300
	21st to end	Day	41% 27% 26% 6%	339
March	1st to 10th	Day	34% 25% 30% 9% 3	500
	11th to 20th	Day	33% 26% 29% 9% 3 1	500
	21st to end	Day	37% 23% 25% 11% 3 1	550
April	1st to 10th	Day	34% 23% 26% 13% 3	500
	11th to 20th	Day	34% 23% 24% 11% 6% 2	492
	21st to end	Day	30% 17% 36% 12% 5% 1	480
May	1st to 10th	Day	30% 19% 27% 15% 6% 2	463
	11th to 20th	Day	27% 15% 31% 16% 7% 3	487
	21st to end	Day	18% 14% 30% 22% 12% 5%	529
June	1st to 10th	Day	22% 17% 30% 21% 8% 2	490
	11th to 20th	Day	19% 14% 28% 25% 11% 2	490
	21st to end	Day	17% 15% 38% 20% 8% 2	490
July	1st to 10th	Day	13% 8% 30% 26% 16% 6%	485
	11th to 20th	Day	16% 10% 28% 25% 16% 6%	484
	21st to end	Day	14% 10% 33% 28% 10% 5%	532
August	1st to 10th	Day	16% 6% 28% 28% 14% 8%	486
	11th to 20th	Day	17% 9% 27% 27% 13% 7%	479
	21st to end	Day	14% 12% 29% 25% 14% 7%	539
September	1st to 10th	Day	23% 11% 23% 21% 15% 7%	490
	11th to 20th	Day	16% 7% 25% 24% 19% 9%	490
	21st to end	Day	30% 11% 25% 18% 11% 4	490
October	1st to 10th	Day	21% 14% 30% 17% 15% 3	490
	11th to 20th	Day	27% 21% 29% 14% 7% 1	490
	21st to end	Day	33% 20% 29% 15% 4	539
November	1st to 10th	Day	27% 20% 28% 16% 8% 2	414
	11th to 20th	Day	38% 23% 27% 10% 1 2	200
	21st to end	Day	39% 23% 32% 6% 1	200
December	1st to 10th	Day	38% 33% 22% 5% 2 2	200
	11th to 20th	Day	46% 19% 29% 5% 2	200
	21st to end	Day	36% 25% 32% 4 2	220
January	1st to 10th	Night	29% 29% 32% 8% 3	800
	11th to 20th	Night	31% 27% 26% 14% 2	800
	21st to end	Night	29% 29% 28% 13% 1	880
February	1st to 10th	Night	32% 25% 28% 15% 1	800
	11th to 20th	Night	30% 31% 29% 10% 1	783
	21st to end	Night	32% 28% 29% 10% 1	660
March	1st to 10th	Night	27% 27% 30% 14% 2	800
	11th to 20th	Night	31% 24% 25% 17% 4 1	800
	21st to end	Night	26% 22% 34% 14% 4 1	880
April	1st to 10th	Night	28% 21% 30% 17% 3	800
	11th to 20th	Night	29% 17% 28% 18% 7% 1	791
	21st to end	Night	23% 14% 32% 27% 5%	642
May	1st to 10th	Night	25% 10% 26% 28% 10% 1	570
	11th to 20th	Night	20% 11% 29% 33% 6%	419
	21st to end	Night	15% 8% 25% 32% 18% 2	411
June	1st to 10th	Night	14% 9% 31% 33% 12%	380
	11th to 20th	Night	13% 11% 25% 40% 12% 1	380
	21st to end	Night	16% 7% 31% 33% 13% 1	380
July	1st to 10th	Night	15% 4 26% 35% 19% 2	370
	11th to 20th	Night	10% 4 23% 39% 23% 1	389
	21st to end	Night	14% 5% 21% 39% 21% 1	624
August	1st to 10th	Night	13% 3 22% 35% 25% 2	567
	11th to 20th	Night	17% 5% 17% 33% 24% 3	564
	21st to end	Night	14% 5% 22% 33% 22% 4	784
September	1st to 10th	Night	18% 8% 23% 28% 19% 3	760
	11th to 20th	Night	16% 6% 20% 28% 26% 4	760
	21st to end	Night	23% 11% 22% 24% 16% 4	760
October	1st to 10th	Night	22% 11% 26% 23% 16% 2	760
	11th to 20th	Night	27% 16% 29% 20% 7% 1	760
	21st to end	Night	32% 15% 32% 17% 4	836
November	1st to 10th	Night	21% 18% 32% 22% 6% 1	780
	11th to 20th	Night	30% 20% 30% 14% 5% 2	800
	21st to end	Night	31% 22% 30% 14% 4 1	800
December	1st to 10th	Night	34% 27% 24% 10% 4	800
	11th to 20th	Night	33% 25% 25% 15% 3	800
	21st to end	Night	31% 24% 31% 13% 1	880

Page generated at 2025-04-23 09:25:02. Version ac07

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