State College
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the State College clear sky chart from 2005-11-06 to 2024-12-02.

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% 3 8% 5% 5% 5% 4 5% 7% 33%	101538
	Night	15% 10% 3 8% 5% 4 4 4 5% 7% 34%	98006
Transparency	Day	48% 6% 11% 22% 12% 1	105177
	Night	47% 6% 11% 22% 12% 2	102506
Seeing	Day	22% 15% 27% 21% 11% 4	14841
	Night	21% 13% 25% 29% 11% 1	24319

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	14% 17% 6% 10% 5% 5% 4 3 4 5% 27%	2517
	11th to 20th	Day	11% 17% 9% 16% 6% 6% 4 3 4 5% 19%	2836
	21st to end	Day	19% 18% 8% 13% 6% 5% 4 3 3 4 17%	3124
February	1st to 10th	Day	15% 17% 5% 9% 7% 5% 5% 3 4 6% 24%	1710
	11th to 20th	Day	13% 11% 4 12% 7% 5% 5% 4 6% 7% 26%	1663
	21st to end	Day	17% 13% 4 10% 6% 4 4 4 4 6% 28%	1552
March	1st to 10th	Day	21% 12% 4 8% 4 4 4 3 4 7% 29%	3405
	11th to 20th	Day	12% 12% 4 9% 5% 4 5% 3 5% 6% 34%	3480
	21st to end	Day	15% 10% 3 7% 5% 5% 4 3 5% 6% 37%	3841
April	1st to 10th	Day	16% 11% 4 8% 5% 5% 4 4 5% 7% 32%	2280
	11th to 20th	Day	15% 11% 3 8% 4 5% 4 4 5% 6% 35%	2254
	21st to end	Day	20% 8% 3 7% 5% 5% 4 4 5% 6% 34%	2351
May	1st to 10th	Day	27% 8% 3 7% 5% 4 4 3 5% 6% 29%	4082
	11th to 20th	Day	22% 9% 3 8% 5% 5% 4 3 4 7% 28%	4334
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 5% 6% 9% 39%	4823
June	1st to 10th	Day	13% 7% 3 7% 6% 5% 5% 5% 7% 7% 35%	2660
	11th to 20th	Day	13% 6% 3 7% 5% 5% 5% 4 6% 9% 35%	2660
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 5% 7% 9% 38%	2660
July	1st to 10th	Day	7% 7% 3 7% 6% 6% 6% 5% 8% 9% 37%	4440
	11th to 20th	Day	7% 6% 3 8% 5% 6% 6% 5% 8% 9% 37%	4392
	21st to end	Day	10% 8% 3 9% 5% 5% 5% 4 7% 8% 36%	4466
August	1st to 10th	Day	16% 9% 3 8% 6% 5% 5% 4 7% 9% 28%	4104
	11th to 20th	Day	13% 7% 3 8% 5% 5% 7% 5% 7% 7% 33%	3994
	21st to end	Day	11% 7% 2 7% 4 4 4 4 6% 8% 42%	4180
September	1st to 10th	Day	16% 6% 2 6% 4 3 4 4 4 6% 43%	2280
	11th to 20th	Day	14% 5% 2 5% 3 4 4 3 5% 8% 47%	2269
	21st to end	Day	20% 8% 3 6% 4 4 4 4 5% 6% 35%	1988
October	1st to 10th	Day	16% 7% 3 7% 4 4 6% 3 5% 7% 38%	1900
	11th to 20th	Day	17% 8% 3 7% 5% 5% 5% 3 6% 6% 35%	1900
	21st to end	Day	17% 9% 3 7% 4 4 5% 4 5% 7% 36%	2090
November	1st to 10th	Day	10% 8% 2 7% 4 4 5% 5% 5% 6% 43%	1837
	11th to 20th	Day	15% 12% 3 9% 5% 5% 5% 4 5% 5% 32%	1656
	21st to end	Day	17% 12% 5% 8% 7% 5% 4 4 6% 6% 28%	1600
December	1st to 10th	Day	18% 15% 4 10% 6% 5% 5% 4 5% 6% 22%	1528
	11th to 20th	Day	18% 14% 6% 8% 5% 4 4 4 4 6% 26%	1910
	21st to end	Day	21% 17% 6% 11% 6% 5% 5% 3 5% 4 16%	2772
January	1st to 10th	Night	13% 14% 5% 12% 7% 5% 4 4 6% 6% 25%	4429
	11th to 20th	Night	14% 16% 7% 13% 4 5% 4 3 5% 7% 22%	4120
	21st to end	Night	22% 15% 5% 12% 6% 4 4 3 4 4 22%	4532
February	1st to 10th	Night	15% 12% 4 9% 5% 5% 5% 4 5% 6% 30%	2470
	11th to 20th	Night	16% 10% 3 9% 6% 5% 6% 5% 5% 6% 29%	2403
	21st to end	Night	15% 13% 3 10% 6% 5% 4 3 4 5% 31%	1901
March	1st to 10th	Night	21% 13% 4 7% 4 3 4 3 4 5% 32%	3432
	11th to 20th	Night	11% 11% 6% 9% 5% 4 4 4 5% 7% 35%	3480
	21st to end	Night	14% 10% 2 7% 5% 3 4 3 4 5% 43%	3791
April	1st to 10th	Night	17% 13% 4 9% 5% 4 4 4 4 5% 32%	1900
	11th to 20th	Night	16% 8% 3 6% 5% 4 4 5% 5% 7% 37%	1875
	21st to end	Night	17% 7% 2 8% 5% 4 4 4 5% 8% 37%	1844
May	1st to 10th	Night	27% 9% 3 7% 4 4 4 3 4 5% 29%	2813
	11th to 20th	Night	25% 10% 3 6% 4 4 4 4 5% 6% 30%	2542
	21st to end	Night	12% 6% 3 7% 5% 4 4 4 6% 10% 38%	2732
June	1st to 10th	Night	12% 7% 2 6% 4 3 4 4 6% 9% 43%	1520
	11th to 20th	Night	12% 6% 2 7% 5% 4 5% 4 7% 9% 39%	1520
	21st to end	Night	11% 5% 2 5% 4 4 4 4 7% 12% 41%	1520
July	1st to 10th	Night	8% 6% 3 8% 5% 5% 5% 4 7% 9% 40%	2520
	11th to 20th	Night	6% 5% 3 6% 5% 5% 5% 5% 7% 12% 42%	2551
	21st to end	Night	12% 7% 2 7% 5% 5% 4 3 6% 8% 41%	3087
August	1st to 10th	Night	15% 8% 3 7% 4 4 5% 4 6% 8% 35%	2825
	11th to 20th	Night	13% 9% 3 7% 4 4 4 3 6% 7% 40%	2803
	21st to end	Night	11% 7% 2 6% 4 3 4 4 6% 8% 45%	3476
September	1st to 10th	Night	15% 5% 2 5% 4 4 5% 4 4 7% 45%	1900
	11th to 20th	Night	11% 6% 2 4 3 3 4 3 5% 7% 51%	1908
	21st to end	Night	18% 7% 2 6% 5% 4 4 3 5% 6% 40%	2190
October	1st to 10th	Night	17% 6% 2 6% 4 3 4 3 5% 8% 43%	2280
	11th to 20th	Night	15% 7% 2 7% 4 3 5% 3 5% 7% 42%	2280
	21st to end	Night	19% 9% 3 6% 3 4 3 4 6% 6% 38%	2508
November	1st to 10th	Night	10% 8% 2 6% 5% 3 4 3 4 6% 49%	2459
	11th to 20th	Night	16% 11% 3 7% 5% 5% 4 3 5% 7% 34%	2740
	21st to end	Night	16% 11% 4 9% 4 4 5% 4 5% 6% 32%	2800
December	1st to 10th	Night	17% 11% 5% 8% 6% 5% 5% 4 6% 7% 26%	2686
	11th to 20th	Night	18% 11% 4 10% 5% 5% 5% 4 5% 6% 29%	3285
	21st to end	Night	18% 13% 4 10% 7% 5% 5% 4 6% 6% 21%	4884

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	57% 7% 12% 17% 6% 2	2518
	11th to 20th	Day	67% 5% 8% 12% 7% 1	2836
	21st to end	Day	70% 6% 7% 13% 4 1	3124
February	1st to 10th	Day	60% 5% 11% 16% 7% 1	1710
	11th to 20th	Day	55% 6% 10% 22% 7% 1	1672
	21st to end	Day	56% 4 10% 19% 8% 2	1552
March	1st to 10th	Day	55% 5% 10% 23% 7% 1	3405
	11th to 20th	Day	48% 6% 14% 21% 9% 2	3480
	21st to end	Day	47% 5% 12% 21% 13% 2	3841
April	1st to 10th	Day	51% 5% 9% 20% 12% 2	2280
	11th to 20th	Day	48% 6% 9% 19% 15% 3	2254
	21st to end	Day	50% 6% 8% 21% 13% 2	2351
May	1st to 10th	Day	55% 6% 8% 20% 10% 1	4120
	11th to 20th	Day	54% 7% 12% 18% 7% 1	4338
	21st to end	Day	38% 9% 12% 25% 13% 2	4837
June	1st to 10th	Day	44% 8% 11% 22% 14% 1	2660
	11th to 20th	Day	43% 7% 13% 21% 13% 2	2660
	21st to end	Day	39% 8% 13% 27% 13% 1	2660
July	1st to 10th	Day	40% 9% 14% 24% 11% 2	4370
	11th to 20th	Day	38% 9% 14% 24% 15% 1	4317
	21st to end	Day	43% 7% 10% 23% 17% 1	4324
August	1st to 10th	Day	49% 8% 13% 20% 9%	4091
	11th to 20th	Day	45% 8% 9% 27% 10% 1	4033
	21st to end	Day	38% 7% 10% 29% 15% 2	4180
September	1st to 10th	Day	41% 5% 9% 24% 17% 3	2280
	11th to 20th	Day	35% 5% 11% 27% 20% 2	2269
	21st to end	Day	47% 6% 10% 19% 16% 1	1988
October	1st to 10th	Day	40% 5% 8% 25% 18% 4	3160
	11th to 20th	Day	43% 5% 9% 24% 17% 4	3140
	21st to end	Day	32% 5% 14% 30% 18% 1	3428
November	1st to 10th	Day	40% 6% 13% 22% 17% 3	1837
	11th to 20th	Day	53% 5% 9% 21% 10% 2	1656
	21st to end	Day	54% 7% 11% 20% 7%	1600
December	1st to 10th	Day	62% 6% 12% 14% 5%	1528
	11th to 20th	Day	58% 6% 13% 19% 5%	1906
	21st to end	Day	69% 6% 10% 12% 3	2772
January	1st to 10th	Night	55% 6% 11% 20% 7% 1	4429
	11th to 20th	Night	60% 7% 12% 14% 7% 1	4120
	21st to end	Night	65% 5% 8% 16% 6% 1	4532
February	1st to 10th	Night	53% 5% 11% 21% 9% 1	2470
	11th to 20th	Night	52% 6% 11% 20% 11% 1	2405
	21st to end	Night	54% 5% 9% 19% 11% 2	1901
March	1st to 10th	Night	54% 5% 9% 22% 9% 1	3432
	11th to 20th	Night	46% 7% 12% 25% 9% 1	3480
	21st to end	Night	43% 4 8% 23% 19% 3	3791
April	1st to 10th	Night	53% 4 8% 19% 14% 2	1900
	11th to 20th	Night	45% 6% 10% 22% 15% 2	1875
	21st to end	Night	45% 5% 9% 23% 14% 3	1844
May	1st to 10th	Night	56% 6% 7% 18% 10% 2	2840
	11th to 20th	Night	53% 8% 12% 16% 9% 1	2543
	21st to end	Night	38% 9% 15% 22% 12% 4	2739
June	1st to 10th	Night	38% 6% 13% 26% 15% 2	1520
	11th to 20th	Night	38% 8% 14% 23% 15% 2	1520
	21st to end	Night	35% 8% 13% 28% 15% 1	1520
July	1st to 10th	Night	40% 7% 14% 21% 15% 3	2480
	11th to 20th	Night	33% 8% 16% 26% 16% 1	2503
	21st to end	Night	40% 6% 12% 18% 21% 2	2988
August	1st to 10th	Night	46% 8% 14% 22% 10%	2814
	11th to 20th	Night	42% 6% 11% 27% 13% 1	2830
	21st to end	Night	36% 6% 12% 32% 13% 2	3476
September	1st to 10th	Night	38% 6% 11% 24% 18% 3	1900
	11th to 20th	Night	31% 6% 11% 30% 20% 2	1908
	21st to end	Night	44% 5% 10% 22% 17% 1	2190
October	1st to 10th	Night	38% 5% 11% 25% 20% 1	3800
	11th to 20th	Night	34% 5% 10% 26% 20% 4	3779
	21st to end	Night	33% 4 13% 28% 20% 2	4120
November	1st to 10th	Night	36% 5% 13% 25% 19% 2	2459
	11th to 20th	Night	49% 4 10% 22% 12% 3	2740
	21st to end	Night	51% 5% 12% 22% 8% 1	2800
December	1st to 10th	Night	55% 7% 12% 19% 7%	2686
	11th to 20th	Night	55% 6% 11% 20% 7%	3288
	21st to end	Night	60% 7% 12% 17% 4	4884

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	26% 28% 27% 12% 5% 2	180
	11th to 20th	Day	34% 22% 31% 11% 1 1	268
	21st to end	Day	26% 22% 36% 11% 4 1	297
February	1st to 10th	Day	27% 24% 33% 13% 3	270
	11th to 20th	Day	35% 24% 34% 7% 1	270
	21st to end	Day	34% 20% 28% 16% 2	364
March	1st to 10th	Day	29% 21% 28% 18% 4	460
	11th to 20th	Day	30% 22% 29% 15% 4 1	460
	21st to end	Day	26% 22% 30% 15% 5% 2	506
April	1st to 10th	Day	27% 21% 26% 19% 5% 1	460
	11th to 20th	Day	22% 23% 23% 18% 9% 4	452
	21st to end	Day	28% 16% 32% 13% 8% 2	460
May	1st to 10th	Day	30% 17% 27% 13% 10% 3	463
	11th to 20th	Day	24% 17% 28% 16% 13% 4	487
	21st to end	Day	19% 10% 26% 23% 17% 5%	529
June	1st to 10th	Day	19% 13% 27% 25% 12% 3	490
	11th to 20th	Day	18% 10% 24% 29% 14% 4	490
	21st to end	Day	14% 11% 30% 28% 13% 3	490
July	1st to 10th	Day	13% 8% 24% 27% 18% 9%	485
	11th to 20th	Day	9% 6% 28% 30% 20% 7%	484
	21st to end	Day	14% 7% 28% 29% 16% 6%	532
August	1st to 10th	Day	11% 8% 25% 26% 22% 8%	486
	11th to 20th	Day	13% 5% 25% 27% 19% 11%	479
	21st to end	Day	14% 7% 22% 29% 15% 12%	539
September	1st to 10th	Day	17% 8% 21% 27% 19% 8%	490
	11th to 20th	Day	16% 5% 19% 28% 23% 10%	490
	21st to end	Day	26% 11% 22% 21% 14% 5%	490
October	1st to 10th	Day	21% 10% 19% 24% 20% 4	490
	11th to 20th	Day	20% 16% 28% 23% 11% 2	490
	21st to end	Day	23% 14% 32% 23% 7% 1	539
November	1st to 10th	Day	17% 16% 29% 26% 11% 2	435
	11th to 20th	Day	24% 22% 29% 18% 6% 1	256
	21st to end	Day	24% 25% 32% 16% 3 1	200
December	1st to 10th	Day	29% 26% 31% 9% 4 1	182
	11th to 20th	Day	27% 24% 27% 19% 2	180
	21st to end	Day	28% 22% 28% 16% 5%	198
January	1st to 10th	Night	22% 22% 34% 18% 3	760
	11th to 20th	Night	27% 17% 29% 23% 3	760
	21st to end	Night	23% 20% 32% 23% 3	836
February	1st to 10th	Night	26% 17% 29% 26% 2	760
	11th to 20th	Night	27% 24% 31% 16% 1	743
	21st to end	Night	28% 19% 31% 21% 2	628
March	1st to 10th	Night	25% 15% 32% 24% 3	760
	11th to 20th	Night	26% 18% 29% 22% 5%	760
	21st to end	Night	24% 16% 32% 22% 6% 1	836
April	1st to 10th	Night	26% 18% 30% 22% 5%	760
	11th to 20th	Night	22% 14% 32% 25% 7% 1	751
	21st to end	Night	23% 12% 28% 30% 7%	704
May	1st to 10th	Night	24% 9% 24% 31% 11% 1	570
	11th to 20th	Night	18% 10% 28% 34% 10%	408
	21st to end	Night	15% 6% 21% 35% 22% 1	411
June	1st to 10th	Night	15% 6% 21% 38% 19% 1	380
	11th to 20th	Night	13% 6% 21% 42% 18%	380
	21st to end	Night	11% 6% 23% 44% 16% 1	380
July	1st to 10th	Night	12% 5% 18% 41% 22% 3	370
	11th to 20th	Night	7% 2 18% 42% 29% 2	386
	21st to end	Night	11% 3 18% 45% 22% 1	624
August	1st to 10th	Night	10% 2 15% 43% 28% 2	567
	11th to 20th	Night	14% 5% 12% 37% 27% 4	569
	21st to end	Night	14% 3 17% 33% 30% 3	836
September	1st to 10th	Night	18% 4 17% 35% 24% 3	760
	11th to 20th	Night	14% 5% 16% 31% 30% 5%	760
	21st to end	Night	21% 8% 19% 28% 20% 3	760
October	1st to 10th	Night	20% 7% 21% 28% 21% 3	760
	11th to 20th	Night	20% 13% 23% 32% 11% 1	760
	21st to end	Night	23% 14% 24% 32% 7%	836
November	1st to 10th	Night	15% 11% 27% 34% 11% 1	780
	11th to 20th	Night	25% 17% 23% 26% 8% 1	800
	21st to end	Night	24% 17% 27% 27% 5% 1	800
December	1st to 10th	Night	27% 17% 30% 21% 5%	768
	11th to 20th	Night	26% 17% 28% 25% 4	760
	21st to end	Night	25% 16% 29% 27% 3	836

Page generated at 2024-11-29 10:43:09. Version ac07

Copyright © 2024 Attilla Danko.