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 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% 11% 4 10% 6% 5% 5% 4 5% 6% 30%	108742
	Night	14% 11% 4 11% 6% 5% 4 4 5% 6% 30%	109942
Transparency	Day	52% 7% 11% 19% 10% 1	112382
	Night	52% 7% 11% 19% 10% 1	114442
Seeing	Day	25% 19% 28% 18% 9% 3	15040
	Night	23% 18% 25% 23% 9% 1	24711

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	12% 17% 8% 26% 6% 4 4 3 3 4 15%	3732
	11th to 20th	Day	10% 17% 9% 23% 10% 8% 4 3 2 3 12%	4060
	21st to end	Day	17% 16% 11% 12% 8% 4 3 3 4 5% 19%	4466
February	1st to 10th	Day	15% 18% 6% 13% 7% 5% 5% 3 4 5% 20%	1800
	11th to 20th	Day	16% 13% 6% 13% 7% 5% 5% 5% 5% 5% 20%	1753
	21st to end	Day	17% 14% 5% 12% 6% 4 3 4 4 5% 24%	1583
March	1st to 10th	Day	18% 10% 6% 9% 6% 4 4 4 5% 6% 28%	3435
	11th to 20th	Day	11% 12% 7% 11% 5% 6% 5% 4 5% 5% 30%	3480
	21st to end	Day	15% 10% 3 7% 5% 5% 5% 4 5% 6% 34%	3815
April	1st to 10th	Day	13% 16% 4 7% 6% 4 5% 4 6% 6% 29%	2261
	11th to 20th	Day	15% 12% 3 6% 6% 5% 5% 4 5% 6% 34%	2254
	21st to end	Day	19% 11% 3 8% 5% 5% 4 3 5% 6% 31%	2398
May	1st to 10th	Day	25% 10% 4 7% 4 5% 4 3 5% 6% 27%	4082
	11th to 20th	Day	21% 11% 3 7% 5% 5% 5% 4 5% 7% 27%	4236
	21st to end	Day	12% 6% 2 7% 5% 5% 6% 4 7% 9% 37%	4823
June	1st to 10th	Day	15% 8% 3 7% 5% 5% 6% 5% 6% 8% 33%	2660
	11th to 20th	Day	14% 7% 3 7% 6% 5% 5% 4 7% 9% 33%	2660
	21st to end	Day	13% 7% 2 6% 6% 4 5% 5% 6% 9% 36%	2660
July	1st to 10th	Day	9% 7% 3 8% 6% 6% 5% 5% 7% 8% 37%	4440
	11th to 20th	Day	9% 6% 2 7% 6% 6% 5% 5% 8% 10% 37%	4280
	21st to end	Day	11% 8% 3 9% 7% 5% 5% 4 6% 7% 36%	4466
August	1st to 10th	Day	18% 8% 3 7% 6% 5% 6% 5% 6% 8% 28%	4104
	11th to 20th	Day	13% 6% 3 8% 7% 6% 6% 5% 7% 7% 33%	4044
	21st to end	Day	10% 6% 3 8% 5% 5% 5% 4 6% 8% 40%	4190
September	1st to 10th	Day	16% 8% 2 6% 4 4 5% 3 5% 7% 41%	2280
	11th to 20th	Day	13% 7% 2 7% 4 4 4 3 5% 8% 44%	2214
	21st to end	Day	19% 9% 3 7% 5% 4 4 4 6% 5% 33%	2019
October	1st to 10th	Day	15% 8% 2 8% 6% 5% 4 3 5% 6% 37%	1900
	11th to 20th	Day	17% 11% 3 7% 5% 5% 5% 3 5% 5% 35%	1900
	21st to end	Day	18% 13% 3 7% 4 4 4 4 5% 6% 33%	2090
November	1st to 10th	Day	11% 9% 4 7% 5% 5% 4 3 6% 5% 40%	1892
	11th to 20th	Day	13% 13% 5% 9% 5% 5% 5% 4 5% 7% 28%	1615
	21st to end	Day	16% 16% 7% 9% 6% 5% 4 4 4 6% 24%	1600
December	1st to 10th	Day	15% 13% 6% 22% 7% 5% 4 3 5% 3 16%	2600
	11th to 20th	Day	19% 16% 5% 11% 5% 5% 3 3 4 5% 24%	2990
	21st to end	Day	17% 22% 7% 12% 6% 5% 4 3 4 4 15%	3960
January	1st to 10th	Night	10% 16% 8% 25% 9% 4 4 3 3 4 14%	6211
	11th to 20th	Night	10% 14% 8% 21% 11% 6% 4 2 4 5% 14%	5900
	21st to end	Night	15% 15% 6% 14% 9% 6% 4 3 4 5% 19%	6490
February	1st to 10th	Night	14% 13% 5% 12% 7% 5% 5% 4 5% 5% 25%	2600
	11th to 20th	Night	15% 12% 5% 12% 7% 6% 6% 4 5% 6% 22%	2533
	21st to end	Night	15% 12% 4 13% 6% 4 4 4 4 5% 27%	1960
March	1st to 10th	Night	20% 11% 4 8% 5% 5% 4 4 5% 6% 28%	3418
	11th to 20th	Night	12% 9% 7% 9% 5% 4 5% 3 6% 6% 33%	3480
	21st to end	Night	13% 11% 3 9% 4 4 4 3 5% 6% 39%	3817
April	1st to 10th	Night	14% 14% 4 9% 6% 4 4 3 5% 5% 32%	1917
	11th to 20th	Night	14% 9% 3 6% 5% 4 4 4 5% 8% 37%	1875
	21st to end	Night	14% 10% 3 9% 5% 4 4 3 5% 7% 37%	1798
May	1st to 10th	Night	26% 10% 2 8% 5% 4 4 3 4 6% 28%	2813
	11th to 20th	Night	21% 13% 2 7% 5% 4 4 4 4 5% 30%	2655
	21st to end	Night	12% 9% 3 8% 4 4 5% 4 6% 9% 36%	2732
June	1st to 10th	Night	11% 7% 3 6% 5% 5% 4 4 6% 8% 43%	1520
	11th to 20th	Night	11% 5% 3 6% 6% 5% 5% 4 6% 9% 40%	1520
	21st to end	Night	10% 5% 2 5% 5% 5% 5% 5% 7% 10% 42%	1520
July	1st to 10th	Night	10% 7% 3 8% 5% 6% 5% 5% 6% 8% 38%	2520
	11th to 20th	Night	7% 5% 2 6% 5% 5% 5% 4 7% 10% 44%	2675
	21st to end	Night	12% 8% 2 7% 5% 5% 4 3 6% 7% 40%	3087
August	1st to 10th	Night	18% 7% 2 7% 4 5% 4 5% 6% 8% 34%	2825
	11th to 20th	Night	13% 9% 2 7% 4 4 5% 4 5% 7% 41%	2785
	21st to end	Night	9% 6% 2 8% 4 4 4 4 6% 8% 45%	3434
September	1st to 10th	Night	14% 6% 2 6% 4 4 5% 3 5% 6% 46%	1900
	11th to 20th	Night	10% 6% 2 5% 3 4 3 4 6% 8% 50%	1962
	21st to end	Night	18% 7% 3 6% 4 4 4 3 4 7% 39%	2160
October	1st to 10th	Night	15% 8% 2 6% 4 4 4 3 5% 7% 42%	2280
	11th to 20th	Night	15% 9% 2 6% 4 5% 5% 4 4 6% 38%	2280
	21st to end	Night	19% 11% 3 7% 4 3 4 3 5% 6% 36%	2508
November	1st to 10th	Night	10% 10% 4 7% 4 4 4 4 4 6% 45%	2405
	11th to 20th	Night	15% 12% 4 8% 6% 5% 4 4 5% 6% 31%	2781
	21st to end	Night	16% 14% 5% 8% 6% 6% 5% 3 5% 5% 28%	2800
December	1st to 10th	Night	13% 12% 6% 21% 7% 5% 4 3 4 5% 19%	4580
	11th to 20th	Night	18% 12% 7% 13% 6% 5% 4 3 4 5% 23%	5205
	21st to end	Night	16% 19% 8% 13% 6% 5% 5% 3 4 4 18%	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	71% 6% 8% 11% 3 1	3733
	11th to 20th	Day	77% 4 6% 7% 4 1	4060
	21st to end	Day	69% 4 8% 12% 7% 1	4466
February	1st to 10th	Day	65% 5% 10% 13% 6% 1	1800
	11th to 20th	Day	62% 7% 9% 15% 7%	1762
	21st to end	Day	61% 5% 11% 15% 6% 2	1583
March	1st to 10th	Day	56% 6% 10% 22% 6%	3435
	11th to 20th	Day	53% 8% 15% 17% 7% 1	3480
	21st to end	Day	48% 7% 13% 20% 11% 1	3815
April	1st to 10th	Day	53% 6% 11% 16% 11% 2	2261
	11th to 20th	Day	51% 6% 9% 17% 14% 2	2254
	21st to end	Day	53% 5% 9% 20% 11% 1	2398
May	1st to 10th	Day	57% 7% 8% 19% 9% 1	4120
	11th to 20th	Day	55% 8% 12% 17% 7% 1	4240
	21st to end	Day	40% 8% 15% 22% 13% 2	4837
June	1st to 10th	Day	46% 9% 11% 22% 11% 1	2660
	11th to 20th	Day	45% 8% 13% 19% 13% 1	2660
	21st to end	Day	42% 7% 13% 25% 12%	2660
July	1st to 10th	Day	43% 8% 13% 24% 11% 2	4370
	11th to 20th	Day	38% 8% 15% 24% 14% 1	4206
	21st to end	Day	46% 7% 9% 22% 16% 1	4324
August	1st to 10th	Day	50% 10% 14% 19% 8%	4091
	11th to 20th	Day	46% 7% 11% 27% 9%	4083
	21st to end	Day	40% 7% 13% 27% 12% 2	4190
September	1st to 10th	Day	43% 6% 9% 22% 16% 3	2280
	11th to 20th	Day	38% 6% 10% 26% 18% 1	2214
	21st to end	Day	50% 7% 11% 17% 13% 1	2019
October	1st to 10th	Day	40% 5% 9% 26% 19% 2	3160
	11th to 20th	Day	44% 6% 8% 23% 11% 8%	3140
	21st to end	Day	35% 5% 12% 28% 19% 1	3428
November	1st to 10th	Day	44% 6% 12% 19% 16% 3	1892
	11th to 20th	Day	54% 6% 11% 16% 10% 2	1615
	21st to end	Day	60% 6% 10% 17% 6%	1600
December	1st to 10th	Day	64% 12% 11% 9% 4	2600
	11th to 20th	Day	63% 4 10% 19% 4	2986
	21st to end	Day	72% 5% 8% 11% 5%	3960
January	1st to 10th	Night	71% 7% 7% 10% 5%	6211
	11th to 20th	Night	70% 7% 9% 10% 3 1	5900
	21st to end	Night	66% 6% 8% 13% 6% 1	6490
February	1st to 10th	Night	59% 7% 10% 17% 7%	2600
	11th to 20th	Night	59% 6% 11% 16% 8%	2535
	21st to end	Night	59% 5% 10% 16% 9% 1	1960
March	1st to 10th	Night	55% 6% 10% 21% 7% 1	3418
	11th to 20th	Night	48% 7% 15% 22% 8% 1	3480
	21st to end	Night	45% 5% 12% 21% 16% 2	3817
April	1st to 10th	Night	54% 5% 11% 17% 12% 1	1917
	11th to 20th	Night	45% 7% 12% 19% 14% 2	1875
	21st to end	Night	46% 6% 11% 22% 12% 3	1798
May	1st to 10th	Night	57% 6% 8% 17% 10% 2	2840
	11th to 20th	Night	54% 9% 10% 18% 8% 1	2656
	21st to end	Night	42% 9% 14% 21% 11% 4	2739
June	1st to 10th	Night	38% 9% 12% 26% 14% 1	1520
	11th to 20th	Night	39% 10% 13% 24% 12% 2	1520
	21st to end	Night	35% 10% 14% 25% 15%	1520
July	1st to 10th	Night	42% 8% 12% 21% 15% 3	2480
	11th to 20th	Night	33% 8% 17% 25% 16% 1	2627
	21st to end	Night	42% 6% 13% 19% 18% 2	2988
August	1st to 10th	Night	46% 10% 14% 22% 8%	2814
	11th to 20th	Night	42% 6% 11% 29% 12%	2812
	21st to end	Night	37% 7% 12% 31% 12% 2	3434
September	1st to 10th	Night	40% 5% 10% 24% 18% 3	1900
	11th to 20th	Night	31% 6% 12% 29% 20% 1	1962
	21st to end	Night	46% 5% 12% 21% 16% 1	2160
October	1st to 10th	Night	37% 6% 9% 27% 21% 1	3800
	11th to 20th	Night	37% 6% 10% 23% 15% 9%	3779
	21st to end	Night	35% 5% 12% 26% 20% 2	4120
November	1st to 10th	Night	40% 5% 13% 21% 18% 3	2405
	11th to 20th	Night	52% 7% 11% 18% 10% 3	2781
	21st to end	Night	55% 8% 11% 18% 7% 1	2800
December	1st to 10th	Night	61% 11% 12% 13% 3	4580
	11th to 20th	Night	63% 5% 12% 15% 4	5208
	21st to end	Night	68% 7% 8% 11% 6%	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	35% 32% 23% 6% 4	229
	11th to 20th	Day	41% 30% 25% 3 1	300
	21st to end	Day	33% 32% 26% 7% 2	330
February	1st to 10th	Day	35% 32% 26% 5% 1	300
	11th to 20th	Day	47% 26% 24% 3	300
	21st to end	Day	37% 28% 26% 8% 1	343
March	1st to 10th	Day	33% 25% 25% 13% 3	460
	11th to 20th	Day	33% 25% 27% 10% 4 1	460
	21st to end	Day	32% 27% 25% 11% 4 1	506
April	1st to 10th	Day	30% 27% 26% 13% 3 1	460
	11th to 20th	Day	24% 27% 25% 14% 7% 3	452
	21st to end	Day	30% 22% 32% 11% 5% 1	460
May	1st to 10th	Day	33% 18% 26% 14% 6% 2	463
	11th to 20th	Day	25% 18% 32% 14% 8% 3	487
	21st to end	Day	16% 14% 30% 23% 12% 4	529
June	1st to 10th	Day	19% 18% 28% 22% 10% 2	490
	11th to 20th	Day	22% 13% 28% 23% 11% 3	490
	21st to end	Day	16% 14% 32% 26% 9% 2	490
July	1st to 10th	Day	12% 10% 31% 23% 17% 7%	485
	11th to 20th	Day	11% 10% 33% 27% 13% 6%	484
	21st to end	Day	14% 8% 33% 28% 12% 6%	532
August	1st to 10th	Day	12% 11% 24% 28% 18% 6%	486
	11th to 20th	Day	16% 9% 26% 26% 15% 8%	479
	21st to end	Day	13% 11% 27% 25% 14% 10%	539
September	1st to 10th	Day	18% 11% 23% 25% 15% 8%	490
	11th to 20th	Day	14% 5% 24% 30% 19% 8%	490
	21st to end	Day	27% 15% 25% 17% 12% 5%	490
October	1st to 10th	Day	21% 14% 24% 23% 14% 3	490
	11th to 20th	Day	26% 20% 26% 19% 8% 1	490
	21st to end	Day	28% 21% 30% 17% 5%	539
November	1st to 10th	Day	23% 21% 29% 18% 9% 2	462
	11th to 20th	Day	28% 26% 33% 10% 3	215
	21st to end	Day	33% 25% 34% 7% 1	200
December	1st to 10th	Day	39% 31% 22% 7% 2 1	200
	11th to 20th	Day	40% 21% 32% 7% 1	200
	21st to end	Day	37% 25% 27% 9% 3	220
January	1st to 10th	Night	30% 32% 25% 10% 3	800
	11th to 20th	Night	31% 29% 24% 14% 2	800
	21st to end	Night	28% 29% 29% 13% 1	880
February	1st to 10th	Night	32% 26% 25% 15% 2	800
	11th to 20th	Night	32% 32% 26% 9% 1	783
	21st to end	Night	31% 25% 28% 15% 1	647
March	1st to 10th	Night	27% 26% 27% 18% 2	760
	11th to 20th	Night	29% 26% 23% 17% 5%	760
	21st to end	Night	24% 25% 31% 15% 5%	836
April	1st to 10th	Night	27% 23% 30% 18% 3	760
	11th to 20th	Night	23% 19% 29% 20% 8%	751
	21st to end	Night	20% 16% 31% 26% 5% 1	658
May	1st to 10th	Night	23% 14% 26% 28% 9% 1	570
	11th to 20th	Night	18% 15% 26% 32% 9%	469
	21st to end	Night	13% 8% 26% 31% 20% 1	411
June	1st to 10th	Night	11% 9% 27% 35% 16% 1	380
	11th to 20th	Night	14% 7% 27% 36% 15% 1	380
	21st to end	Night	11% 7% 29% 39% 13%	380
July	1st to 10th	Night	12% 5% 21% 40% 20% 2	370
	11th to 20th	Night	9% 4 21% 39% 25% 3	458
	21st to end	Night	11% 8% 20% 39% 20% 2	624
August	1st to 10th	Night	11% 4 19% 40% 25% 2	567
	11th to 20th	Night	15% 6% 16% 37% 23% 3	564
	21st to end	Night	12% 6% 22% 34% 23% 4	807
September	1st to 10th	Night	17% 6% 22% 30% 22% 3	760
	11th to 20th	Night	13% 6% 18% 32% 26% 5%	760
	21st to end	Night	21% 12% 21% 25% 17% 3	760
October	1st to 10th	Night	19% 11% 24% 26% 18% 2	760
	11th to 20th	Night	23% 17% 27% 23% 8% 1	760
	21st to end	Night	27% 19% 26% 21% 6%	836
November	1st to 10th	Night	18% 18% 29% 27% 8% 1	780
	11th to 20th	Night	28% 22% 27% 18% 5% 2	800
	21st to end	Night	29% 21% 30% 16% 4 1	800
December	1st to 10th	Night	33% 26% 24% 13% 4	800
	11th to 20th	Night	31% 27% 24% 16% 2	800
	21st to end	Night	29% 25% 29% 17% 1	880

Page generated at 2025-02-22 06:51:37. Version ac07

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