Rickett's Glen State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rickett's Glen State Park clear sky chart from 2005-11-06 to 2025-08-05.

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	17% 9% 3 8% 5% 5% 5% 4 6% 7% 33%	126005
	Night	17% 9% 3 7% 5% 4 4 4 5% 7% 35%	122035
Transparency	Day	49% 4 11% 22% 12% 2	129561
	Night	47% 3 12% 23% 13% 2	126565
Seeing	Day	25% 17% 28% 18% 9% 3	15735
	Night	22% 15% 29% 24% 9% 1	24991

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	11% 15% 5% 12% 5% 4 4 4 5% 7% 28%	3597
	11th to 20th	Day	11% 15% 8% 18% 7% 6% 4 3 4 5% 20%	3690
	21st to end	Day	16% 12% 7% 10% 6% 4 4 3 4 5% 29%	4466
February	1st to 10th	Day	15% 14% 5% 10% 5% 6% 5% 4 6% 5% 27%	1800
	11th to 20th	Day	14% 12% 4 10% 7% 5% 4 4 6% 6% 30%	1813
	21st to end	Day	19% 12% 3 9% 6% 4 4 3 5% 6% 28%	1650
March	1st to 10th	Day	19% 12% 4 7% 5% 4 4 3 4 5% 34%	4631
	11th to 20th	Day	12% 9% 4 9% 5% 4 4 4 5% 6% 38%	4980
	21st to end	Day	16% 10% 3 6% 5% 4 5% 4 5% 6% 36%	5688
April	1st to 10th	Day	17% 14% 3 8% 5% 4 4 3 4 6% 31%	2400
	11th to 20th	Day	17% 11% 3 7% 4 5% 4 4 5% 5% 35%	2374
	21st to end	Day	17% 8% 3 8% 5% 4 5% 3 6% 6% 37%	2400
May	1st to 10th	Day	28% 8% 2 6% 5% 4 5% 4 5% 7% 26%	6066
	11th to 20th	Day	26% 8% 3 7% 5% 5% 5% 4 6% 7% 26%	6318
	21st to end	Day	22% 6% 2 5% 5% 4 5% 5% 7% 8% 31%	6949
June	1st to 10th	Day	16% 7% 2 6% 6% 5% 6% 4 6% 8% 34%	2800
	11th to 20th	Day	18% 7% 2 6% 6% 5% 5% 4 6% 7% 34%	2800
	21st to end	Day	15% 6% 2 5% 5% 4 4 4 7% 9% 37%	2800
July	1st to 10th	Day	9% 6% 3 7% 6% 6% 6% 5% 6% 9% 37%	6360
	11th to 20th	Day	12% 6% 3 7% 5% 6% 6% 5% 9% 10% 31%	6360
	21st to end	Day	13% 7% 2 7% 4 5% 6% 4 7% 8% 37%	6757
August	1st to 10th	Day	22% 7% 2 7% 5% 5% 5% 3 5% 7% 31%	4156
	11th to 20th	Day	17% 6% 2 6% 5% 5% 6% 4 6% 9% 34%	3885
	21st to end	Day	18% 5% 2 5% 3 4 5% 4 7% 9% 39%	4180
September	1st to 10th	Day	17% 6% 2 6% 4 4 4 4 5% 8% 41%	2280
	11th to 20th	Day	14% 6% 2 5% 3 4 3 4 5% 6% 46%	2280
	21st to end	Day	23% 7% 3 6% 4 4 4 3 5% 6% 35%	2026
October	1st to 10th	Day	20% 7% 3 5% 4 4 4 3 6% 8% 37%	1900
	11th to 20th	Day	18% 9% 3 7% 5% 4 4 3 4 7% 36%	1900
	21st to end	Day	20% 10% 2 7% 5% 4 4 4 5% 6% 32%	2052
November	1st to 10th	Day	15% 8% 3 7% 5% 4 4 3 4 6% 42%	1761
	11th to 20th	Day	16% 11% 3 8% 5% 4 4 3 5% 6% 34%	1740
	21st to end	Day	18% 11% 3 7% 6% 5% 4 4 5% 7% 31%	1600
December	1st to 10th	Day	16% 13% 5% 9% 5% 6% 5% 4 5% 4 28%	2600
	11th to 20th	Day	21% 14% 4 8% 4 3 3 3 5% 5% 30%	2986
	21st to end	Day	17% 14% 5% 11% 7% 5% 5% 3 5% 6% 23%	3960
January	1st to 10th	Night	12% 9% 4 11% 6% 5% 5% 4 6% 8% 29%	6349
	11th to 20th	Night	11% 12% 5% 14% 5% 5% 5% 4 5% 7% 26%	6177
	21st to end	Night	14% 11% 4 11% 7% 5% 5% 4 5% 6% 28%	6490
February	1st to 10th	Night	15% 11% 3 8% 5% 5% 4 4 5% 7% 31%	2600
	11th to 20th	Night	14% 10% 4 10% 7% 5% 5% 4 6% 6% 29%	2472
	21st to end	Night	15% 12% 4 9% 5% 5% 4 4 5% 6% 30%	1980
March	1st to 10th	Night	18% 12% 4 7% 5% 4 4 4 4 5% 34%	5193
	11th to 20th	Night	12% 7% 4 7% 4 4 4 3 5% 7% 43%	4979
	21st to end	Night	15% 10% 3 7% 5% 4 5% 3 5% 5% 38%	5243
April	1st to 10th	Night	17% 13% 4 8% 6% 4 4 4 5% 6% 30%	2000
	11th to 20th	Night	17% 8% 2 6% 5% 5% 4 3 6% 8% 36%	1975
	21st to end	Night	18% 8% 2 6% 4 3 4 4 6% 7% 40%	2000
May	1st to 10th	Night	32% 8% 3 6% 4 3 4 3 5% 6% 27%	3916
	11th to 20th	Night	25% 8% 3 6% 4 4 5% 3 5% 5% 33%	3575
	21st to end	Night	24% 7% 2 4 5% 4 3 3 5% 8% 35%	3926
June	1st to 10th	Night	17% 5% 2 6% 4 4 5% 4 6% 8% 40%	1600
	11th to 20th	Night	16% 5% 2 6% 5% 4 5% 3 7% 9% 39%	1600
	21st to end	Night	13% 6% 2 4 4 4 5% 4 8% 9% 41%	1600
July	1st to 10th	Night	13% 7% 3 7% 4 5% 5% 4 5% 8% 41%	3600
	11th to 20th	Night	17% 7% 3 6% 4 4 4 4 6% 9% 35%	3600
	21st to end	Night	13% 5% 2 4 4 4 4 3 5% 7% 48%	4078
August	1st to 10th	Night	21% 7% 2 5% 4 4 4 4 7% 8% 34%	2861
	11th to 20th	Night	18% 8% 3 6% 3 3 4 3 4 5% 44%	2911
	21st to end	Night	15% 4 1 4 3 4 4 3 5% 8% 47%	3476
September	1st to 10th	Night	17% 5% 2 5% 3 4 4 4 4 7% 43%	1900
	11th to 20th	Night	13% 6% 2 5% 3 4 3 3 5% 6% 50%	1900
	21st to end	Night	20% 7% 2 6% 4 4 3 3 4 6% 41%	2151
October	1st to 10th	Night	21% 9% 2 5% 3 3 3 3 3 7% 42%	2280
	11th to 20th	Night	18% 8% 2 5% 4 4 3 4 4 5% 43%	2280
	21st to end	Night	21% 8% 2 6% 4 4 5% 3 5% 7% 34%	2545
November	1st to 10th	Night	11% 8% 3 7% 4 4 4 4 5% 6% 44%	2537
	11th to 20th	Night	19% 9% 3 6% 5% 5% 4 4 5% 6% 36%	2657
	21st to end	Night	14% 9% 4 7% 5% 5% 5% 4 5% 7% 34%	2800
December	1st to 10th	Night	13% 13% 5% 9% 4 5% 4 4 5% 8% 30%	4580
	11th to 20th	Night	22% 12% 4 7% 4 4 4 3 4 5% 31%	5208
	21st to end	Night	19% 14% 5% 8% 5% 5% 4 3 4 6% 27%	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	53% 4 8% 23% 10% 2	3598
	11th to 20th	Day	65% 3 7% 15% 9% 1	3720
	21st to end	Day	58% 2 8% 21% 10% 1	4466
February	1st to 10th	Day	58% 3 11% 17% 10% 1	1800
	11th to 20th	Day	54% 3 7% 25% 10% 1	1822
	21st to end	Day	55% 2 9% 22% 9% 2	1650
March	1st to 10th	Day	53% 2 9% 21% 10% 5%	4634
	11th to 20th	Day	45% 2 15% 25% 9% 4	4980
	21st to end	Day	48% 3 11% 15% 20% 4	5688
April	1st to 10th	Day	54% 3 8% 20% 12% 4	2400
	11th to 20th	Day	50% 3 10% 20% 15% 2	2374
	21st to end	Day	46% 2 9% 23% 15% 4	2400
May	1st to 10th	Day	58% 3 11% 17% 10% 1	6075
	11th to 20th	Day	56% 3 10% 21% 10% 1	6322
	21st to end	Day	49% 4 10% 23% 12% 1	6949
June	1st to 10th	Day	47% 4 13% 22% 14% 1	2800
	11th to 20th	Day	47% 4 13% 22% 12% 1	2800
	21st to end	Day	41% 5% 14% 27% 12% 1	2800
July	1st to 10th	Day	43% 7% 12% 25% 13%	6290
	11th to 20th	Day	43% 6% 18% 23% 10%	6285
	21st to end	Day	43% 5% 11% 23% 18% 1	6562
August	1st to 10th	Day	53% 4 12% 19% 11%	4143
	11th to 20th	Day	46% 4 13% 28% 9%	3924
	21st to end	Day	39% 4 12% 33% 10% 1	4180
September	1st to 10th	Day	42% 5% 10% 25% 16% 2	2280
	11th to 20th	Day	37% 3 10% 26% 22% 2	2280
	21st to end	Day	48% 4 10% 20% 17% 1	2026
October	1st to 10th	Day	42% 4 9% 22% 20% 4	3160
	11th to 20th	Day	41% 3 6% 29% 16% 4	3140
	21st to end	Day	35% 2 15% 30% 16% 1	3366
November	1st to 10th	Day	41% 3 13% 25% 17% 2	1761
	11th to 20th	Day	49% 3 10% 22% 13% 2	1740
	21st to end	Day	51% 3 14% 23% 8% 1	1600
December	1st to 10th	Day	56% 5% 11% 22% 6% 1	2600
	11th to 20th	Day	56% 3 14% 17% 10%	2986
	21st to end	Day	62% 3 11% 15% 9%	3960
January	1st to 10th	Night	49% 3 10% 23% 13% 2	6349
	11th to 20th	Night	55% 4 11% 17% 10% 3	6222
	21st to end	Night	55% 3 10% 17% 15% 1	6490
February	1st to 10th	Night	51% 3 13% 23% 9% 1	2600
	11th to 20th	Night	53% 4 9% 21% 11% 2	2474
	21st to end	Night	54% 2 9% 21% 12% 2	1980
March	1st to 10th	Night	52% 3 12% 19% 11% 4	5203
	11th to 20th	Night	41% 2 18% 26% 9% 4	4980
	21st to end	Night	48% 3 7% 17% 21% 4	5243
April	1st to 10th	Night	55% 2 8% 20% 12% 3	2000
	11th to 20th	Night	46% 4 10% 22% 16% 1	1975
	21st to end	Night	44% 3 10% 22% 18% 3	2000
May	1st to 10th	Night	58% 3 9% 19% 9% 2	3923
	11th to 20th	Night	52% 5% 13% 17% 12% 1	3576
	21st to end	Night	49% 3 12% 22% 12% 2	3927
June	1st to 10th	Night	42% 4 11% 27% 17% 1	1600
	11th to 20th	Night	41% 4 15% 27% 11% 1	1600
	21st to end	Night	37% 6% 14% 29% 13% 1	1600
July	1st to 10th	Night	41% 5% 14% 23% 16% 1	3560
	11th to 20th	Night	45% 5% 15% 23% 11% 1	3552
	21st to end	Night	34% 4 13% 26% 21% 1	3958
August	1st to 10th	Night	47% 5% 16% 23% 9% 1	2850
	11th to 20th	Night	43% 3 12% 27% 14%	2938
	21st to end	Night	36% 4 12% 34% 15% 1	3476
September	1st to 10th	Night	41% 5% 10% 27% 16% 2	1900
	11th to 20th	Night	35% 3 11% 28% 22% 2	1900
	21st to end	Night	45% 2 9% 24% 19% 1	2151
October	1st to 10th	Night	43% 3 10% 23% 20% 1	3800
	11th to 20th	Night	34% 2 11% 27% 19% 6%	3779
	21st to end	Night	34% 2 16% 28% 17% 2	4181
November	1st to 10th	Night	39% 3 13% 24% 18% 2	2537
	11th to 20th	Night	48% 3 10% 23% 13% 3	2657
	21st to end	Night	47% 3 14% 25% 10% 1	2800
December	1st to 10th	Night	50% 3 14% 28% 5%	4580
	11th to 20th	Night	55% 3 12% 18% 12% 1	5208
	21st to end	Night	58% 2 9% 19% 11% 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	34% 26% 30% 8% 3 1	200
	11th to 20th	Day	38% 26% 29% 6% 1	227
	21st to end	Day	28% 31% 26% 12% 2	330
February	1st to 10th	Day	35% 29% 28% 7% 1	300
	11th to 20th	Day	38% 29% 29% 4	360
	21st to end	Day	35% 24% 29% 10% 1	414
March	1st to 10th	Day	34% 23% 27% 13% 3	500
	11th to 20th	Day	29% 26% 30% 11% 3 1	500
	21st to end	Day	32% 25% 27% 11% 3 1	550
April	1st to 10th	Day	34% 25% 25% 11% 4 1	500
	11th to 20th	Day	33% 24% 23% 12% 5% 2	492
	21st to end	Day	26% 22% 33% 12% 5% 1	500
May	1st to 10th	Day	32% 20% 29% 10% 8% 2	503
	11th to 20th	Day	27% 16% 30% 17% 9% 2	527
	21st to end	Day	25% 10% 28% 19% 15% 3	573
June	1st to 10th	Day	21% 14% 31% 22% 11% 2	530
	11th to 20th	Day	22% 14% 25% 26% 11% 1	530
	21st to end	Day	19% 11% 33% 26% 10% 1	530
July	1st to 10th	Day	13% 9% 29% 28% 17% 3	525
	11th to 20th	Day	11% 9% 27% 31% 18% 4	524
	21st to end	Day	16% 10% 31% 28% 12% 4	576
August	1st to 10th	Day	13% 9% 28% 24% 20% 6%	502
	11th to 20th	Day	18% 7% 27% 27% 15% 6%	479
	21st to end	Day	16% 12% 25% 25% 13% 9%	539
September	1st to 10th	Day	21% 11% 24% 21% 17% 7%	490
	11th to 20th	Day	14% 7% 26% 26% 18% 9%	490
	21st to end	Day	29% 12% 23% 21% 12% 3	490
October	1st to 10th	Day	28% 12% 20% 23% 13% 4	490
	11th to 20th	Day	23% 20% 28% 20% 7% 1	490
	21st to end	Day	27% 18% 29% 20% 6% 1	519
November	1st to 10th	Day	24% 19% 28% 19% 9% 1	395
	11th to 20th	Day	27% 23% 28% 18% 3 1	340
	21st to end	Day	32% 24% 33% 9% 3	200
December	1st to 10th	Day	33% 29% 26% 7% 5% 1	200
	11th to 20th	Day	36% 26% 29% 9% 2	200
	21st to end	Day	29% 27% 31% 10% 2	220
January	1st to 10th	Night	23% 24% 38% 13% 3	800
	11th to 20th	Night	24% 23% 32% 19% 3	800
	21st to end	Night	19% 26% 35% 17% 2	880
February	1st to 10th	Night	26% 22% 34% 17% 2	800
	11th to 20th	Night	27% 24% 36% 12% 1	783
	21st to end	Night	28% 21% 35% 13% 2	660
March	1st to 10th	Night	27% 23% 33% 16% 2	800
	11th to 20th	Night	26% 23% 30% 18% 4	800
	21st to end	Night	25% 22% 33% 15% 4 1	880
April	1st to 10th	Night	26% 22% 31% 18% 3	800
	11th to 20th	Night	23% 18% 34% 18% 6%	791
	21st to end	Night	24% 16% 32% 24% 5%	800
May	1st to 10th	Night	29% 13% 25% 24% 10%	541
	11th to 20th	Night	22% 11% 30% 30% 6% 1	394
	21st to end	Night	22% 7% 22% 36% 13%	433
June	1st to 10th	Night	19% 4 25% 37% 15% 1	400
	11th to 20th	Night	19% 7% 26% 35% 13%	400
	21st to end	Night	13% 4 29% 42% 12% 1	400
July	1st to 10th	Night	13% 5% 22% 39% 20% 2	390
	11th to 20th	Night	10% 7% 18% 44% 20% 1	388
	21st to end	Night	12% 4 21% 43% 18% 2	502
August	1st to 10th	Night	16% 2 16% 43% 21% 2	579
	11th to 20th	Night	16% 3 17% 35% 26% 3	638
	21st to end	Night	16% 5% 21% 33% 24% 2	836
September	1st to 10th	Night	19% 6% 23% 31% 19% 2	760
	11th to 20th	Night	16% 6% 22% 27% 25% 4	760
	21st to end	Night	23% 9% 21% 29% 16% 2	760
October	1st to 10th	Night	27% 8% 22% 25% 16% 2	760
	11th to 20th	Night	23% 12% 28% 29% 6% 1	760
	21st to end	Night	25% 14% 32% 24% 5%	836
November	1st to 10th	Night	16% 16% 34% 26% 7% 1	780
	11th to 20th	Night	25% 19% 30% 21% 5% 1	800
	21st to end	Night	23% 20% 34% 20% 3 1	800
December	1st to 10th	Night	27% 23% 32% 15% 4	800
	11th to 20th	Night	24% 20% 33% 20% 3	800
	21st to end	Night	26% 19% 35% 17% 3	880

Page generated at 2025-08-02 01:32:24. Version ac07

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