Prince Gallitzin State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Prince Gallitzin 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% 11% 4 10% 6% 5% 5% 4 5% 6% 30%	137962
	Night	14% 11% 4 11% 6% 5% 4 3 5% 6% 30%	134393
Transparency	Day	52% 6% 10% 20% 10% 1	141559
	Night	52% 7% 11% 19% 11% 1	138868
Seeing	Day	25% 19% 27% 17% 8% 3	16839
	Night	23% 18% 26% 23% 9% 1	26380

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% 17% 7% 25% 7% 4 4 3 3 4 13%	4838
	11th to 20th	Day	9% 16% 9% 23% 11% 7% 4 2 2 3 14%	5280
	21st to end	Day	15% 13% 9% 11% 10% 7% 5% 3 4 4 20%	5780
February	1st to 10th	Day	14% 17% 6% 13% 7% 5% 5% 3 4 5% 21%	1890
	11th to 20th	Day	15% 13% 6% 14% 7% 5% 5% 5% 5% 5% 20%	1843
	21st to end	Day	17% 15% 5% 12% 6% 4 3 4 5% 5% 25%	1703
March	1st to 10th	Day	16% 10% 8% 9% 5% 4 4 3 4 5% 31%	5045
	11th to 20th	Day	12% 11% 6% 10% 5% 5% 5% 4 5% 6% 31%	5090
	21st to end	Day	13% 10% 3 8% 5% 6% 5% 4 5% 6% 34%	5586
April	1st to 10th	Day	14% 16% 5% 8% 6% 4 5% 4 5% 6% 29%	2499
	11th to 20th	Day	14% 12% 3 6% 6% 5% 5% 4 5% 6% 33%	2494
	21st to end	Day	19% 11% 3 8% 5% 4 4 3 5% 7% 32%	2650
May	1st to 10th	Day	20% 9% 3 8% 5% 5% 6% 4 6% 6% 27%	7616
	11th to 20th	Day	18% 10% 3 7% 5% 5% 5% 5% 6% 8% 29%	7921
	21st to end	Day	21% 8% 3 7% 4 5% 5% 4 5% 6% 31%	9045
June	1st to 10th	Day	14% 8% 3 6% 5% 5% 6% 5% 6% 8% 35%	2940
	11th to 20th	Day	14% 8% 3 7% 6% 5% 5% 4 7% 9% 32%	2940
	21st to end	Day	13% 6% 2 6% 6% 5% 5% 4 7% 9% 36%	2940
July	1st to 10th	Day	8% 6% 3 8% 6% 6% 6% 5% 7% 8% 38%	6360
	11th to 20th	Day	9% 7% 3 9% 7% 7% 6% 5% 8% 10% 30%	6130
	21st to end	Day	11% 7% 3 8% 5% 5% 5% 4 6% 7% 40%	6424
August	1st to 10th	Day	17% 8% 3 7% 5% 5% 6% 5% 7% 8% 29%	4234
	11th to 20th	Day	13% 6% 3 7% 6% 6% 6% 5% 7% 7% 33%	4174
	21st to end	Day	10% 6% 3 7% 5% 4 5% 4 7% 9% 40%	4322
September	1st to 10th	Day	16% 8% 2 6% 4 3 5% 3 5% 7% 42%	2400
	11th to 20th	Day	12% 7% 2 7% 4 4 4 3 5% 8% 45%	2330
	21st to end	Day	19% 10% 3 7% 5% 4 4 4 6% 5% 33%	2125
October	1st to 10th	Day	15% 8% 2 7% 6% 5% 4 3 5% 7% 38%	2000
	11th to 20th	Day	16% 11% 3 7% 5% 5% 5% 3 6% 5% 34%	2000
	21st to end	Day	17% 13% 3 7% 4 4 4 4 5% 6% 33%	2200
November	1st to 10th	Day	11% 9% 4 7% 5% 5% 4 4 6% 6% 40%	1989
	11th to 20th	Day	13% 15% 6% 9% 5% 5% 5% 4 5% 7% 27%	1696
	21st to end	Day	15% 16% 7% 10% 6% 5% 4 4 4 6% 23%	1680
December	1st to 10th	Day	15% 14% 6% 23% 7% 5% 4 3 5% 3 16%	2680
	11th to 20th	Day	19% 16% 5% 12% 6% 5% 3 3 4 5% 23%	3070
	21st to end	Day	17% 22% 7% 13% 6% 5% 4 3 4 4 15%	4048
January	1st to 10th	Night	10% 17% 8% 24% 10% 5% 4 3 4 4 13%	8053
	11th to 20th	Night	9% 15% 7% 21% 12% 6% 4 3 4 5% 14%	7680
	21st to end	Night	13% 14% 5% 12% 9% 9% 4 3 4 5% 21%	8401
February	1st to 10th	Night	14% 13% 5% 12% 7% 6% 5% 4 5% 4 25%	2730
	11th to 20th	Night	15% 12% 5% 13% 7% 6% 6% 4 5% 6% 22%	2663
	21st to end	Night	15% 13% 5% 13% 6% 4 4 4 4 5% 27%	2095
March	1st to 10th	Night	16% 11% 5% 10% 7% 5% 4 3 5% 5% 30%	5028
	11th to 20th	Night	11% 8% 6% 8% 4 4 4 3 5% 6% 40%	5090
	21st to end	Night	11% 11% 4 10% 5% 4 5% 3 5% 6% 36%	5588
April	1st to 10th	Night	16% 14% 4 9% 5% 4 4 3 5% 5% 31%	2119
	11th to 20th	Night	15% 10% 3 7% 5% 5% 4 4 5% 8% 36%	2075
	21st to end	Night	14% 11% 3 8% 5% 3 4 3 5% 7% 37%	1987
May	1st to 10th	Night	20% 11% 3 8% 5% 5% 4 4 5% 7% 29%	5237
	11th to 20th	Night	18% 13% 3 7% 5% 4 4 3 4 7% 33%	4937
	21st to end	Night	21% 11% 3 7% 4 3 4 4 4 7% 31%	5108
June	1st to 10th	Night	11% 7% 3 6% 5% 4 4 3 5% 8% 43%	1680
	11th to 20th	Night	12% 6% 3 5% 5% 5% 5% 5% 6% 8% 39%	1680
	21st to end	Night	10% 6% 2 5% 5% 5% 4 5% 7% 10% 42%	1680
July	1st to 10th	Night	9% 7% 3 8% 4 5% 5% 5% 6% 9% 38%	3598
	11th to 20th	Night	9% 6% 2 7% 6% 6% 6% 4 8% 10% 36%	3822
	21st to end	Night	10% 7% 2 6% 5% 4 4 3 6% 8% 43%	4427
August	1st to 10th	Night	17% 7% 2 7% 4 5% 4 5% 6% 8% 35%	2915
	11th to 20th	Night	12% 8% 2 7% 4 4 5% 4 5% 7% 41%	2875
	21st to end	Night	9% 6% 2 7% 4 4 4 4 6% 8% 45%	3543
September	1st to 10th	Night	14% 6% 2 6% 4 4 5% 3 5% 6% 47%	2000
	11th to 20th	Night	9% 6% 2 5% 3 4 3 4 6% 8% 50%	2065
	21st to end	Night	19% 8% 3 6% 4 4 4 3 4 7% 38%	2274
October	1st to 10th	Night	15% 7% 2 5% 4 4 4 3 5% 7% 44%	2400
	11th to 20th	Night	15% 9% 2 6% 4 5% 5% 4 4 6% 39%	2400
	21st to end	Night	19% 11% 3 6% 4 3 4 3 5% 5% 37%	2640
November	1st to 10th	Night	10% 10% 4 7% 4 4 4 4 4 6% 44%	2528
	11th to 20th	Night	15% 12% 4 8% 6% 5% 4 4 5% 5% 30%	2920
	21st to end	Night	16% 14% 6% 9% 6% 5% 4 3 5% 5% 28%	2940
December	1st to 10th	Night	13% 12% 6% 21% 7% 5% 4 3 4 5% 19%	4720
	11th to 20th	Night	18% 12% 7% 13% 6% 5% 4 3 4 5% 23%	5345
	21st to end	Night	15% 19% 7% 13% 6% 5% 5% 3 4 4 18%	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	73% 6% 8% 10% 2 1	4839
	11th to 20th	Day	76% 4 5% 8% 6% 1	5280
	21st to end	Day	67% 4 9% 14% 6%	5780
February	1st to 10th	Day	64% 6% 10% 13% 7%	1890
	11th to 20th	Day	63% 7% 9% 14% 6%	1852
	21st to end	Day	61% 5% 11% 15% 6% 2	1703
March	1st to 10th	Day	54% 5% 10% 21% 8% 1	5045
	11th to 20th	Day	51% 7% 14% 20% 7% 2	5090
	21st to end	Day	49% 6% 11% 19% 13% 2	5586
April	1st to 10th	Day	54% 6% 11% 16% 11% 2	2499
	11th to 20th	Day	50% 7% 10% 17% 14% 2	2494
	21st to end	Day	52% 5% 9% 21% 12% 1	2650
May	1st to 10th	Day	55% 7% 10% 19% 8% 2	7651
	11th to 20th	Day	51% 7% 10% 21% 10% 1	7925
	21st to end	Day	51% 6% 10% 18% 14% 1	9061
June	1st to 10th	Day	45% 8% 11% 23% 13%	2940
	11th to 20th	Day	46% 8% 13% 19% 13% 1	2940
	21st to end	Day	42% 7% 13% 25% 12%	2940
July	1st to 10th	Day	42% 8% 11% 26% 12% 2	6290
	11th to 20th	Day	44% 9% 15% 21% 10%	6056
	21st to end	Day	42% 6% 8% 25% 18% 1	6240
August	1st to 10th	Day	49% 10% 14% 19% 8%	4221
	11th to 20th	Day	46% 7% 11% 27% 9%	4213
	21st to end	Day	39% 7% 12% 28% 12% 2	4322
September	1st to 10th	Day	42% 6% 9% 23% 17% 3	2400
	11th to 20th	Day	37% 6% 11% 26% 18% 1	2330
	21st to end	Day	51% 7% 11% 17% 14% 1	2125
October	1st to 10th	Day	39% 5% 8% 26% 19% 2	3260
	11th to 20th	Day	44% 6% 8% 23% 11% 8%	3240
	21st to end	Day	36% 5% 12% 28% 19% 1	3538
November	1st to 10th	Day	43% 6% 12% 20% 16% 3	1989
	11th to 20th	Day	55% 7% 11% 16% 10% 2	1696
	21st to end	Day	61% 6% 9% 17% 6%	1680
December	1st to 10th	Day	65% 11% 10% 9% 4	2680
	11th to 20th	Day	63% 4 10% 19% 4	3066
	21st to end	Day	72% 5% 8% 11% 4	4048
January	1st to 10th	Night	72% 7% 7% 10% 4	8054
	11th to 20th	Night	68% 8% 8% 10% 5% 1	7680
	21st to end	Night	64% 6% 8% 16% 6% 1	8401
February	1st to 10th	Night	58% 7% 9% 17% 8%	2730
	11th to 20th	Night	60% 6% 11% 16% 7%	2665
	21st to end	Night	59% 5% 10% 16% 9% 1	2095
March	1st to 10th	Night	56% 6% 10% 19% 9% 1	5028
	11th to 20th	Night	42% 7% 16% 23% 8% 4	5090
	21st to end	Night	47% 6% 12% 17% 17% 2	5588
April	1st to 10th	Night	55% 6% 11% 16% 12% 1	2119
	11th to 20th	Night	46% 7% 12% 19% 14% 2	2075
	21st to end	Night	46% 6% 11% 23% 12% 2	1987
May	1st to 10th	Night	54% 7% 11% 15% 11% 2	5264
	11th to 20th	Night	50% 8% 10% 23% 8% 1	4938
	21st to end	Night	52% 6% 9% 20% 10% 2	5115
June	1st to 10th	Night	38% 8% 11% 26% 15% 1	1680
	11th to 20th	Night	40% 9% 13% 23% 13% 2	1680
	21st to end	Night	36% 10% 14% 25% 15%	1680
July	1st to 10th	Night	41% 8% 12% 24% 13% 2	3560
	11th to 20th	Night	41% 9% 18% 21% 11% 1	3777
	21st to end	Night	37% 6% 11% 24% 20% 1	4297
August	1st to 10th	Night	45% 10% 14% 22% 9% 1	2904
	11th to 20th	Night	42% 6% 11% 28% 12%	2902
	21st to end	Night	36% 6% 12% 31% 12% 2	3543
September	1st to 10th	Night	39% 5% 10% 25% 18% 3	2000
	11th to 20th	Night	31% 6% 13% 29% 19% 1	2065
	21st to end	Night	47% 5% 11% 20% 16% 1	2274
October	1st to 10th	Night	36% 6% 9% 26% 22% 1	3920
	11th to 20th	Night	37% 6% 10% 23% 15% 9%	3899
	21st to end	Night	35% 5% 12% 26% 20% 2	4252
November	1st to 10th	Night	41% 5% 12% 21% 18% 3	2528
	11th to 20th	Night	52% 7% 11% 18% 10% 3	2920
	21st to end	Night	55% 8% 11% 18% 7% 1	2940
December	1st to 10th	Night	61% 11% 12% 12% 3	4720
	11th to 20th	Night	63% 5% 12% 16% 4	5348
	21st to end	Night	68% 7% 8% 11% 6%	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	36% 31% 24% 6% 4	252
	11th to 20th	Day	44% 30% 23% 3 1	330
	21st to end	Day	36% 31% 25% 7% 1	363
February	1st to 10th	Day	35% 31% 27% 6% 2	330
	11th to 20th	Day	47% 24% 26% 3	330
	21st to end	Day	35% 29% 28% 8% 1	388
March	1st to 10th	Day	35% 26% 25% 11% 3	540
	11th to 20th	Day	35% 24% 27% 9% 4 1	540
	21st to end	Day	32% 28% 25% 11% 3 1	594
April	1st to 10th	Day	32% 26% 26% 12% 3 1	540
	11th to 20th	Day	26% 26% 27% 13% 6% 2	532
	21st to end	Day	29% 21% 32% 12% 5% 1	540
May	1st to 10th	Day	32% 21% 27% 13% 6% 2	543
	11th to 20th	Day	26% 18% 32% 14% 7% 2	567
	21st to end	Day	20% 16% 29% 21% 11% 3	617
June	1st to 10th	Day	18% 19% 28% 23% 9% 2	570
	11th to 20th	Day	24% 15% 28% 21% 9% 3	570
	21st to end	Day	16% 14% 31% 27% 9% 2	570
July	1st to 10th	Day	12% 10% 31% 24% 17% 7%	525
	11th to 20th	Day	10% 11% 31% 28% 14% 6%	524
	21st to end	Day	14% 8% 31% 30% 12% 6%	576
August	1st to 10th	Day	12% 11% 25% 29% 18% 6%	526
	11th to 20th	Day	17% 8% 25% 26% 15% 8%	519
	21st to end	Day	13% 10% 28% 25% 14% 10%	583
September	1st to 10th	Day	18% 12% 22% 24% 15% 8%	530
	11th to 20th	Day	13% 5% 24% 30% 20% 8%	530
	21st to end	Day	27% 15% 25% 17% 12% 5%	530
October	1st to 10th	Day	20% 14% 23% 24% 15% 4	530
	11th to 20th	Day	26% 20% 27% 18% 8% 1	530
	21st to end	Day	28% 22% 29% 16% 5%	583
November	1st to 10th	Day	24% 22% 28% 17% 8% 1	499
	11th to 20th	Day	31% 25% 31% 9% 3	236
	21st to end	Day	35% 25% 32% 7% 1	220
December	1st to 10th	Day	39% 31% 21% 6% 2 1	220
	11th to 20th	Day	41% 20% 32% 6% 1	220
	21st to end	Day	39% 25% 25% 8% 2	242
January	1st to 10th	Night	31% 32% 25% 10% 3	840
	11th to 20th	Night	32% 30% 24% 14% 1	840
	21st to end	Night	28% 29% 29% 12% 1	924
February	1st to 10th	Night	31% 25% 26% 15% 2	840
	11th to 20th	Night	32% 31% 27% 9% 1	823
	21st to end	Night	31% 25% 29% 14% 1	692
March	1st to 10th	Night	28% 25% 28% 17% 2	840
	11th to 20th	Night	29% 25% 24% 16% 5%	840
	21st to end	Night	24% 25% 32% 14% 4	924
April	1st to 10th	Night	28% 23% 29% 17% 3	840
	11th to 20th	Night	24% 20% 28% 20% 8%	831
	21st to end	Night	20% 17% 30% 27% 6% 1	727
May	1st to 10th	Night	23% 14% 27% 28% 8%	630
	11th to 20th	Night	19% 15% 28% 31% 8%	519
	21st to end	Night	16% 9% 26% 29% 19% 1	455
June	1st to 10th	Night	11% 9% 28% 36% 16% 1	420
	11th to 20th	Night	16% 8% 28% 34% 14%	420
	21st to end	Night	11% 7% 29% 39% 14%	420
July	1st to 10th	Night	12% 5% 22% 40% 19% 2	390
	11th to 20th	Night	9% 4 22% 39% 24% 3	483
	21st to end	Night	11% 8% 19% 40% 20% 2	657
August	1st to 10th	Night	11% 4 19% 41% 24% 2	597
	11th to 20th	Night	14% 6% 16% 38% 23% 3	594
	21st to end	Night	12% 5% 23% 34% 23% 4	850
September	1st to 10th	Night	17% 7% 21% 31% 22% 3	800
	11th to 20th	Night	13% 5% 18% 33% 27% 4	800
	21st to end	Night	21% 12% 21% 25% 17% 3	800
October	1st to 10th	Night	19% 11% 23% 27% 19% 2	800
	11th to 20th	Night	23% 17% 28% 23% 8% 1	800
	21st to end	Night	27% 18% 27% 22% 5%	880
November	1st to 10th	Night	19% 17% 28% 27% 8%	820
	11th to 20th	Night	29% 21% 26% 18% 5% 1	840
	21st to end	Night	30% 21% 29% 16% 4	840
December	1st to 10th	Night	32% 27% 25% 13% 4	840
	11th to 20th	Night	31% 27% 24% 15% 2	840
	21st to end	Night	29% 25% 28% 16% 1	924

Page generated at 2026-06-28 02:10:44. Version ac07

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