Sky Meadows State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sky Meadows State Park clear sky chart from 2005-11-06 to 2024-03-28.

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	14% 6% 2 5% 5% 3 5% 5% 5% 8% 41%	78827
	Night	14% 6% 2 5% 5% 3 4 5% 5% 7% 43%	81175
Transparency	Day	40% 6% 12% 23% 15% 3	78541
	Night	39% 6% 12% 24% 17% 3	80980
Seeing	Day	18% 13% 25% 24% 15% 5%	14069
	Night	17% 9% 29% 31% 13% 1	23807

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	17% 5% 2 5% 5% 3 5% 4 4 7% 44%	2688
	11th to 20th	Day	14% 10% 3 7% 5% 3 5% 5% 4 5% 39%	2840
	21st to end	Day	16% 9% 4 7% 6% 3 5% 5% 4 6% 36%	3124
February	1st to 10th	Day	13% 9% 3 6% 6% 3 5% 6% 5% 6% 38%	1710
	11th to 20th	Day	17% 6% 3 5% 5% 3 4 4 6% 7% 39%	1671
	21st to end	Day	17% 9% 4 5% 6% 3 3 4 5% 5% 40%	1586
March	1st to 10th	Day	13% 7% 2 5% 5% 3 4 3 4 6% 47%	2090
	11th to 20th	Day	15% 6% 3 6% 5% 4 5% 5% 4 7% 41%	2090
	21st to end	Day	17% 7% 3 7% 6% 4 4 4 5% 7% 38%	2255
April	1st to 10th	Day	11% 5% 3 7% 5% 3 6% 4 6% 8% 42%	2158
	11th to 20th	Day	13% 6% 2 5% 6% 3 4 5% 5% 6% 46%	2134
	21st to end	Day	17% 6% 3 6% 5% 3 4 5% 5% 7% 39%	2176
May	1st to 10th	Day	17% 6% 3 6% 5% 4 5% 5% 5% 10% 36%	2340
	11th to 20th	Day	19% 5% 2 5% 6% 4 5% 5% 5% 7% 35%	2348
	21st to end	Day	15% 6% 2 5% 5% 3 4 6% 6% 8% 40%	2725
June	1st to 10th	Day	11% 5% 3 4 4 3 5% 5% 6% 10% 43%	2520
	11th to 20th	Day	11% 5% 2 6% 6% 3 6% 6% 7% 10% 38%	2520
	21st to end	Day	10% 3 2 5% 5% 3 6% 7% 6% 10% 43%	2520
July	1st to 10th	Day	9% 5% 3 5% 7% 4 6% 5% 6% 9% 40%	2520
	11th to 20th	Day	6% 4 2 5% 6% 5% 6% 6% 8% 11% 42%	2369
	21st to end	Day	10% 6% 2 5% 7% 4 6% 7% 7% 10% 36%	2547
August	1st to 10th	Day	8% 6% 3 6% 7% 4 7% 8% 7% 10% 34%	2327
	11th to 20th	Day	12% 5% 2 6% 6% 3 6% 6% 7% 9% 37%	2249
	21st to end	Day	10% 5% 2 6% 5% 4 5% 5% 8% 8% 42%	2376
September	1st to 10th	Day	15% 7% 2 5% 6% 3 4 4 5% 6% 44%	2160
	11th to 20th	Day	13% 5% 2 4 4 3 4 4 5% 8% 48%	2136
	21st to end	Day	19% 6% 3 5% 5% 2 5% 4 5% 6% 39%	1890
October	1st to 10th	Day	17% 5% 2 5% 5% 3 3 4 4 6% 46%	1800
	11th to 20th	Day	17% 5% 2 4 6% 3 4 4 4 5% 47%	1800
	21st to end	Day	15% 5% 2 4 4 2 4 3 4 6% 50%	1980
November	1st to 10th	Day	13% 6% 2 3 4 3 3 4 4 7% 51%	1818
	11th to 20th	Day	15% 5% 3 4 4 2 4 4 5% 6% 49%	1638
	21st to end	Day	15% 5% 2 4 5% 3 4 4 4 7% 47%	1520
December	1st to 10th	Day	16% 8% 3 6% 5% 4 5% 5% 5% 8% 37%	1520
	11th to 20th	Day	16% 4 2 5% 5% 3 4 4 5% 8% 43%	1910
	21st to end	Day	17% 6% 2 5% 5% 3 6% 5% 7% 8% 35%	2772
January	1st to 10th	Night	12% 7% 3 5% 5% 3 4 4 5% 7% 45%	4255
	11th to 20th	Night	18% 8% 2 4 4 3 3 4 4 6% 45%	4120
	21st to end	Night	17% 10% 3 7% 4 2 4 4 4 6% 39%	4532
February	1st to 10th	Night	13% 7% 3 7% 6% 3 5% 5% 6% 6% 41%	2470
	11th to 20th	Night	17% 8% 3 5% 4 3 4 5% 5% 6% 41%	2394
	21st to end	Night	17% 8% 3 5% 5% 3 4 5% 5% 6% 41%	1865
March	1st to 10th	Night	13% 5% 2 4 5% 3 4 5% 5% 6% 47%	2090
	11th to 20th	Night	17% 6% 2 4 5% 3 4 3 5% 7% 44%	2090
	21st to end	Night	16% 6% 3 6% 4 4 3 4 5% 6% 42%	2256
April	1st to 10th	Night	13% 7% 3 7% 5% 2 6% 5% 5% 7% 41%	1800
	11th to 20th	Night	13% 5% 2 6% 5% 3 5% 4 6% 8% 44%	1775
	21st to end	Night	17% 4 2 4 4 3 5% 5% 5% 8% 42%	1800
May	1st to 10th	Night	17% 6% 2 5% 6% 3 5% 5% 6% 8% 38%	1620
	11th to 20th	Night	17% 6% 3 6% 5% 3 4 4 6% 8% 37%	1544
	21st to end	Night	14% 5% 2 5% 4 3 5% 5% 6% 10% 42%	1550
June	1st to 10th	Night	10% 5% 2 6% 4 2 5% 6% 7% 9% 44%	1440
	11th to 20th	Night	12% 5% 2 5% 5% 3 4 5% 7% 9% 42%	1440
	21st to end	Night	8% 4 3 5% 5% 3 5% 5% 8% 10% 44%	1440
July	1st to 10th	Night	10% 6% 3 5% 6% 4 5% 5% 7% 10% 39%	1440
	11th to 20th	Night	6% 4 2 5% 5% 4 6% 6% 8% 10% 46%	1586
	21st to end	Night	8% 4 3 4 5% 4 5% 6% 8% 13% 40%	1771
August	1st to 10th	Night	8% 6% 2 6% 6% 4 7% 6% 7% 10% 39%	1611
	11th to 20th	Night	11% 6% 2 6% 6% 4 6% 7% 6% 9% 38%	1632
	21st to end	Night	11% 5% 2 5% 5% 3 6% 6% 7% 10% 41%	1980
September	1st to 10th	Night	16% 5% 2 5% 5% 3 4 5% 5% 7% 44%	1800
	11th to 20th	Night	12% 5% 2 5% 4 3 3 3 4 6% 52%	1821
	21st to end	Night	19% 6% 2 6% 5% 3 4 3 4 6% 43%	2069
October	1st to 10th	Night	19% 5% 2 4 4 4 3 3 5% 7% 45%	2160
	11th to 20th	Night	15% 4 2 4 4 3 4 4 4 6% 51%	2160
	21st to end	Night	15% 5% 2 5% 4 2 3 4 5% 6% 49%	2376
November	1st to 10th	Night	11% 6% 2 4 4 2 3 4 4 6% 52%	2259
	11th to 20th	Night	13% 7% 2 4 3 3 4 4 4 7% 49%	2540
	21st to end	Night	13% 4 2 4 4 3 5% 4 5% 8% 47%	2660
December	1st to 10th	Night	16% 7% 3 5% 5% 3 4 5% 5% 6% 41%	2660
	11th to 20th	Night	16% 6% 3 5% 5% 2 5% 4 5% 6% 43%	3285
	21st to end	Night	15% 6% 3 5% 6% 3 5% 6% 7% 9% 35%	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	40% 4 7% 31% 14% 4	2689
	11th to 20th	Day	47% 4 9% 20% 15% 6%	2840
	21st to end	Day	48% 4 11% 22% 13% 2	3124
February	1st to 10th	Day	44% 6% 13% 23% 12% 3	1710
	11th to 20th	Day	43% 5% 9% 24% 16% 3	1680
	21st to end	Day	46% 5% 11% 19% 15% 4	1586
March	1st to 10th	Day	39% 3 11% 25% 20% 3	2090
	11th to 20th	Day	42% 5% 10% 19% 19% 5%	2090
	21st to end	Day	45% 5% 10% 19% 16% 4	2255
April	1st to 10th	Day	39% 6% 12% 19% 19% 5%	2158
	11th to 20th	Day	37% 6% 11% 21% 19% 6%	2134
	21st to end	Day	45% 5% 10% 22% 14% 4	2176
May	1st to 10th	Day	43% 6% 14% 20% 14% 2	2340
	11th to 20th	Day	46% 7% 13% 19% 12% 2	2352
	21st to end	Day	40% 8% 14% 26% 11% 1	2725
June	1st to 10th	Day	37% 7% 15% 25% 16% 2	2520
	11th to 20th	Day	39% 9% 16% 21% 13% 2	2520
	21st to end	Day	33% 9% 16% 25% 16% 2	2520
July	1st to 10th	Day	38% 9% 13% 22% 16% 2	2450
	11th to 20th	Day	32% 9% 15% 27% 15% 2	2298
	21st to end	Day	40% 9% 12% 21% 16% 2	2405
August	1st to 10th	Day	42% 9% 15% 23% 11% 1	2314
	11th to 20th	Day	41% 9% 14% 21% 14% 1	2249
	21st to end	Day	36% 8% 16% 25% 12% 3	2376
September	1st to 10th	Day	41% 6% 12% 19% 19% 4	2160
	11th to 20th	Day	35% 5% 10% 27% 20% 3	2136
	21st to end	Day	44% 6% 10% 20% 18% 2	1890
October	1st to 10th	Day	39% 6% 11% 25% 16% 4	1800
	11th to 20th	Day	38% 5% 9% 24% 20% 3	1800
	21st to end	Day	35% 4 9% 26% 22% 3	1980
November	1st to 10th	Day	33% 4 11% 25% 22% 5%	1818
	11th to 20th	Day	37% 4 11% 22% 22% 5%	1638
	21st to end	Day	37% 5% 10% 28% 18% 2	1520
December	1st to 10th	Day	44% 5% 12% 26% 11% 2	1520
	11th to 20th	Day	40% 3 12% 31% 10% 4	1906
	21st to end	Day	43% 7% 14% 25% 10% 1	2772
January	1st to 10th	Night	36% 4 10% 28% 18% 3	4255
	11th to 20th	Night	41% 4 9% 24% 19% 4	4120
	21st to end	Night	45% 4 10% 26% 14% 1	4532
February	1st to 10th	Night	43% 6% 12% 24% 14% 2	2470
	11th to 20th	Night	44% 3 10% 23% 16% 5%	2396
	21st to end	Night	45% 4 11% 22% 14% 5%	1865
March	1st to 10th	Night	36% 5% 11% 28% 17% 3	2090
	11th to 20th	Night	41% 4 10% 21% 20% 4	2090
	21st to end	Night	41% 5% 11% 21% 16% 5%	2256
April	1st to 10th	Night	42% 5% 10% 21% 18% 4	1800
	11th to 20th	Night	36% 5% 12% 22% 19% 6%	1775
	21st to end	Night	40% 6% 13% 25% 12% 5%	1800
May	1st to 10th	Night	42% 6% 13% 22% 13% 4	1620
	11th to 20th	Night	45% 7% 13% 19% 15% 2	1545
	21st to end	Night	38% 7% 17% 25% 11% 1	1551
June	1st to 10th	Night	34% 9% 13% 26% 16% 2	1440
	11th to 20th	Night	38% 8% 16% 22% 14% 2	1440
	21st to end	Night	32% 9% 16% 23% 17% 3	1440
July	1st to 10th	Night	38% 8% 17% 20% 13% 4	1400
	11th to 20th	Night	31% 10% 17% 23% 16% 3	1534
	21st to end	Night	32% 9% 18% 25% 15% 1	1672
August	1st to 10th	Night	40% 8% 15% 23% 13% 1	1600
	11th to 20th	Night	40% 10% 13% 22% 14% 2	1632
	21st to end	Night	37% 9% 15% 22% 14% 3	1980
September	1st to 10th	Night	39% 6% 11% 21% 18% 4	1800
	11th to 20th	Night	34% 5% 9% 27% 21% 3	1821
	21st to end	Night	43% 5% 9% 22% 18% 3	2069
October	1st to 10th	Night	40% 5% 11% 24% 17% 3	2160
	11th to 20th	Night	35% 4 10% 27% 22% 3	2160
	21st to end	Night	36% 5% 9% 25% 22% 4	2376
November	1st to 10th	Night	33% 4 10% 26% 21% 6%	2259
	11th to 20th	Night	36% 4 7% 25% 22% 6%	2540
	21st to end	Night	36% 4 12% 25% 20% 4	2660
December	1st to 10th	Night	43% 5% 11% 26% 13% 2	2660
	11th to 20th	Night	41% 4 10% 24% 17% 4	3288
	21st to end	Night	42% 7% 16% 21% 13% 1	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	29% 25% 26% 16% 4	231
	11th to 20th	Day	27% 26% 29% 15% 3	270
	21st to end	Day	22% 27% 34% 13% 4 1	297
February	1st to 10th	Day	22% 23% 36% 14% 4	270
	11th to 20th	Day	32% 25% 35% 7% 1	278
	21st to end	Day	27% 19% 35% 16% 3	382
March	1st to 10th	Day	22% 23% 27% 25% 3	460
	11th to 20th	Day	23% 23% 30% 17% 6% 1	460
	21st to end	Day	20% 19% 33% 20% 6% 1	490
April	1st to 10th	Day	21% 21% 26% 22% 8% 1	420
	11th to 20th	Day	15% 17% 26% 23% 15% 3	412
	21st to end	Day	25% 14% 30% 20% 10% 2	420
May	1st to 10th	Day	22% 16% 29% 18% 12% 3	423
	11th to 20th	Day	21% 10% 29% 23% 13% 4	447
	21st to end	Day	19% 5% 23% 25% 21% 7%	485
June	1st to 10th	Day	15% 8% 24% 27% 20% 7%	450
	11th to 20th	Day	14% 10% 25% 27% 18% 6%	450
	21st to end	Day	10% 6% 25% 31% 22% 6%	450
July	1st to 10th	Day	12% 4 13% 30% 27% 13%	445
	11th to 20th	Day	5% 2 17% 34% 31% 11%	444
	21st to end	Day	11% 4 18% 33% 26% 9%	488
August	1st to 10th	Day	11% 4 16% 27% 29% 12%	446
	11th to 20th	Day	12% 3 17% 30% 25% 13%	439
	21st to end	Day	8% 5% 18% 29% 25% 16%	495
September	1st to 10th	Day	17% 6% 17% 25% 22% 13%	450
	11th to 20th	Day	15% 4 16% 30% 22% 12%	450
	21st to end	Day	22% 11% 18% 27% 18% 4	450
October	1st to 10th	Day	17% 8% 18% 27% 23% 6%	450
	11th to 20th	Day	15% 14% 26% 29% 13% 3	450
	21st to end	Day	17% 12% 34% 25% 9% 3	495
November	1st to 10th	Day	17% 11% 28% 28% 13% 3	436
	11th to 20th	Day	20% 15% 29% 24% 11% 1	298
	21st to end	Day	18% 19% 31% 25% 6% 1	180
December	1st to 10th	Day	18% 22% 33% 22% 5% 1	180
	11th to 20th	Day	23% 18% 29% 24% 6%	180
	21st to end	Day	22% 16% 32% 22% 9%	198
January	1st to 10th	Night	17% 18% 40% 22% 3	760
	11th to 20th	Night	21% 13% 33% 28% 4	760
	21st to end	Night	18% 15% 42% 22% 2	836
February	1st to 10th	Night	16% 15% 38% 28% 2	760
	11th to 20th	Night	21% 20% 39% 18% 2	743
	21st to end	Night	23% 16% 38% 20% 3	628
March	1st to 10th	Night	19% 15% 39% 24% 3	760
	11th to 20th	Night	22% 17% 33% 22% 5% 1	760
	21st to end	Night	19% 13% 39% 23% 5% 1	821
April	1st to 10th	Night	18% 18% 36% 24% 4	720
	11th to 20th	Night	15% 11% 35% 28% 9% 1	711
	21st to end	Night	20% 10% 31% 32% 7%	720
May	1st to 10th	Night	20% 6% 28% 32% 13%	540
	11th to 20th	Night	19% 5% 26% 37% 13%	483
	21st to end	Night	14% 3 20% 42% 21% 1	389
June	1st to 10th	Night	11% 2 23% 41% 23%	360
	11th to 20th	Night	13% 5% 18% 40% 23% 1	360
	21st to end	Night	6% 3 22% 48% 20% 1	360
July	1st to 10th	Night	11% 2 16% 40% 27% 4	350
	11th to 20th	Night	6% 1 13% 37% 40% 3	490
	21st to end	Night	8% 1 15% 44% 29% 3	591
August	1st to 10th	Night	9% 2 10% 45% 31% 3	537
	11th to 20th	Night	10% 3 14% 38% 32% 3	568
	21st to end	Night	13% 2 16% 39% 26% 4	792
September	1st to 10th	Night	16% 3 14% 34% 29% 4	720
	11th to 20th	Night	13% 3 18% 32% 30% 4	720
	21st to end	Night	21% 4 22% 31% 22% 1	720
October	1st to 10th	Night	21% 5% 20% 30% 22% 3	720
	11th to 20th	Night	15% 8% 27% 36% 13% 1	720
	21st to end	Night	18% 9% 31% 31% 11%	792
November	1st to 10th	Night	14% 7% 32% 35% 11% 1	740
	11th to 20th	Night	17% 12% 32% 29% 8% 1	760
	21st to end	Night	16% 12% 33% 31% 8%	760
December	1st to 10th	Night	19% 14% 36% 25% 6%	760
	11th to 20th	Night	17% 8% 41% 30% 4	760
	21st to end	Night	17% 12% 34% 34% 3	836

Page generated at 2024-03-24 23:37:00. Version ac07

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