Wading River
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wading River clear sky chart from 2005-11-06 to 2026-03-03.

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	16% 7% 2 6% 4 4 4 3 5% 7% 43%	130675
	Night	17% 8% 3 6% 4 4 4 3 5% 6% 41%	130489
Transparency	Day	26% 38% 8% 15% 11% 2	134217
	Night	29% 36% 7% 15% 11% 2	135034
Seeing	Day	18% 5% 22% 30% 19% 6%	16700
	Night	20% 7% 27% 30% 13% 2	25864

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	12% 7% 2 6% 3 4 4 3 5% 6% 47%	4661
	11th to 20th	Day	16% 7% 2 6% 3 3 3 3 4 5% 46%	4650
	21st to end	Day	16% 8% 3 5% 3 4 4 3 4 7% 44%	5339
February	1st to 10th	Day	17% 6% 3 6% 4 4 4 4 5% 7% 40%	1984
	11th to 20th	Day	15% 6% 3 5% 4 3 4 3 4 7% 44%	2048
	21st to end	Day	18% 8% 2 6% 3 3 4 3 4 7% 41%	1730
March	1st to 10th	Day	20% 7% 2 4 3 3 3 3 4 6% 45%	4496
	11th to 20th	Day	12% 9% 2 5% 4 3 4 4 6% 7% 45%	4650
	21st to end	Day	18% 8% 2 6% 4 3 4 3 5% 6% 41%	5970
April	1st to 10th	Day	18% 8% 2 5% 4 4 4 4 5% 7% 41%	2400
	11th to 20th	Day	17% 6% 2 5% 5% 3 3 4 5% 6% 45%	2374
	21st to end	Day	18% 5% 2 4 3 4 4 3 7% 6% 43%	2500
May	1st to 10th	Day	26% 8% 3 6% 3 3 3 3 6% 8% 32%	5886
	11th to 20th	Day	20% 9% 3 6% 3 3 3 3 4 7% 40%	6061
	21st to end	Day	18% 6% 2 5% 3 3 4 4 6% 7% 41%	6949
June	1st to 10th	Day	15% 6% 2 5% 4 4 4 4 6% 9% 42%	2800
	11th to 20th	Day	14% 6% 2 5% 3 4 5% 4 6% 9% 42%	2800
	21st to end	Day	10% 6% 2 6% 4 4 4 3 5% 9% 46%	2800
July	1st to 10th	Day	11% 7% 2 7% 5% 5% 5% 4 6% 10% 38%	6360
	11th to 20th	Day	10% 6% 2 7% 5% 5% 5% 5% 7% 10% 38%	6360
	21st to end	Day	14% 6% 2 6% 4 4 4 4 6% 7% 45%	6926
August	1st to 10th	Day	17% 5% 2 6% 4 4 5% 4 6% 8% 38%	4334
	11th to 20th	Day	11% 5% 2 7% 4 4 4 3 5% 8% 48%	3850
	21st to end	Day	7% 4 2 5% 4 3 5% 4 6% 8% 52%	4312
September	1st to 10th	Day	13% 6% 2 5% 4 3 5% 3 5% 6% 48%	2400
	11th to 20th	Day	11% 5% 2 4 3 3 3 2 4 7% 54%	2256
	21st to end	Day	18% 5% 2 7% 4 4 4 4 5% 6% 40%	2200
October	1st to 10th	Day	21% 6% 2 4 2 3 3 2 4 6% 46%	2180
	11th to 20th	Day	15% 5% 2 5% 3 3 4 3 6% 7% 47%	1990
	21st to end	Day	18% 7% 2 5% 4 3 4 3 4 7% 42%	1980
November	1st to 10th	Day	14% 6% 2 5% 4 4 5% 3 4 6% 49%	1851
	11th to 20th	Day	16% 6% 2 5% 4 2 3 3 5% 7% 47%	1890
	21st to end	Day	15% 7% 2 6% 3 4 4 4 5% 6% 44%	1890
December	1st to 10th	Day	15% 8% 2 6% 5% 3 4 3 5% 7% 44%	2684
	11th to 20th	Day	21% 8% 2 4 2 2 3 2 4 5% 47%	3066
	21st to end	Day	18% 10% 3 7% 4 3 4 3 4 5% 39%	4048
January	1st to 10th	Night	15% 7% 3 6% 4 3 3 2 4 6% 47%	8234
	11th to 20th	Night	17% 8% 3 7% 4 3 3 3 4 5% 44%	8235
	21st to end	Night	16% 9% 3 7% 4 4 4 3 5% 6% 38%	8840
February	1st to 10th	Night	15% 10% 3 6% 5% 4 4 4 5% 7% 38%	2635
	11th to 20th	Night	18% 8% 2 5% 4 4 3 4 6% 7% 38%	2458
	21st to end	Night	19% 7% 2 5% 5% 4 4 3 4 6% 39%	2076
March	1st to 10th	Night	19% 10% 2 6% 3 3 3 2 4 6% 41%	5389
	11th to 20th	Night	15% 10% 3 7% 4 4 4 3 5% 6% 41%	5303
	21st to end	Night	21% 8% 2 6% 3 4 4 3 5% 5% 38%	4962
April	1st to 10th	Night	19% 7% 2 6% 5% 4 4 3 5% 6% 38%	2000
	11th to 20th	Night	18% 8% 3 5% 4 4 4 3 4 6% 42%	1975
	21st to end	Night	18% 8% 3 6% 5% 3 3 3 5% 5% 42%	1900
May	1st to 10th	Night	25% 10% 3 8% 4 4 4 3 5% 7% 28%	4054
	11th to 20th	Night	24% 9% 2 7% 4 3 4 4 5% 6% 32%	3861
	21st to end	Night	22% 9% 2 6% 4 4 5% 4 5% 7% 32%	3926
June	1st to 10th	Night	18% 6% 3 5% 4 4 5% 3 6% 7% 40%	1600
	11th to 20th	Night	17% 6% 2 6% 3 3 4 4 6% 10% 40%	1600
	21st to end	Night	11% 6% 2 5% 6% 4 6% 5% 6% 9% 40%	1600
July	1st to 10th	Night	12% 8% 3 8% 5% 4 5% 4 7% 9% 34%	3600
	11th to 20th	Night	14% 8% 3 9% 5% 5% 5% 4 7% 9% 32%	3600
	21st to end	Night	14% 6% 3 6% 5% 4 4 4 5% 7% 43%	3926
August	1st to 10th	Night	21% 6% 3 7% 5% 4 4 4 7% 8% 32%	2765
	11th to 20th	Night	12% 5% 2 7% 4 5% 5% 4 7% 8% 40%	3196
	21st to end	Night	8% 4 2 4 3 3 4 3 6% 9% 54%	3586
September	1st to 10th	Night	14% 5% 2 7% 5% 5% 5% 4 5% 6% 44%	2000
	11th to 20th	Night	14% 5% 2 4 2 4 4 3 4 7% 52%	2143
	21st to end	Night	18% 6% 2 7% 5% 5% 4 3 5% 6% 39%	2200
October	1st to 10th	Night	20% 7% 2 6% 4 3 3 3 4 6% 41%	2216
	11th to 20th	Night	16% 5% 2 5% 3 4 4 3 4 5% 48%	2410
	21st to end	Night	21% 7% 2 6% 4 3 4 3 5% 6% 39%	2860
November	1st to 10th	Night	13% 6% 2 6% 4 4 4 3 4 7% 47%	2667
	11th to 20th	Night	18% 8% 2 5% 4 3 3 3 4 6% 46%	2730
	21st to end	Night	15% 6% 1 6% 4 4 4 3 5% 7% 45%	2730
December	1st to 10th	Night	16% 8% 3 5% 4 4 3 2 4 5% 45%	4714
	11th to 20th	Night	23% 8% 2 5% 4 3 3 2 4 4 41%	5348
	21st to end	Night	18% 9% 3 7% 4 3 4 3 4 5% 41%	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	30% 23% 7% 22% 16% 2	4662
	11th to 20th	Day	30% 22% 7% 19% 16% 7%	4680
	21st to end	Day	33% 24% 9% 20% 14% 1	5339
February	1st to 10th	Day	19% 59% 8% 8% 5%	1984
	11th to 20th	Day	19% 58% 3 10% 10% 1	2057
	21st to end	Day	17% 59% 5% 11% 7% 2	1730
March	1st to 10th	Day	30% 31% 7% 12% 11% 9%	4499
	11th to 20th	Day	26% 31% 10% 22% 10% 1	4650
	21st to end	Day	33% 29% 7% 9% 17% 4	5970
April	1st to 10th	Day	20% 62% 3 7% 6% 1	2400
	11th to 20th	Day	16% 62% 4 9% 10%	2374
	21st to end	Day	16% 62% 3 10% 8% 1	2500
May	1st to 10th	Day	40% 31% 14% 10% 5%	5897
	11th to 20th	Day	36% 30% 9% 15% 9% 1	6065
	21st to end	Day	33% 31% 7% 19% 10%	6949
June	1st to 10th	Day	16% 62% 4 10% 8%	2800
	11th to 20th	Day	16% 62% 5% 10% 7% 1	2800
	21st to end	Day	13% 60% 6% 10% 9% 1	2800
July	1st to 10th	Day	34% 30% 10% 14% 11% 1	6290
	11th to 20th	Day	32% 29% 16% 16% 7%	6285
	21st to end	Day	29% 27% 9% 19% 15% 1	6728
August	1st to 10th	Day	32% 37% 10% 16% 5%	4320
	11th to 20th	Day	23% 37% 10% 25% 5%	3886
	21st to end	Day	15% 38% 11% 21% 14% 1	4312
September	1st to 10th	Day	16% 57% 6% 12% 8% 1	2400
	11th to 20th	Day	16% 56% 4 11% 12% 1	2256
	21st to end	Day	22% 57% 5% 8% 7% 1	2200
October	1st to 10th	Day	19% 37% 7% 14% 18% 4	3557
	11th to 20th	Day	13% 36% 6% 17% 25% 3	3218
	21st to end	Day	16% 36% 10% 21% 16% 2	3180
November	1st to 10th	Day	19% 53% 7% 10% 10% 1	1851
	11th to 20th	Day	15% 54% 4 12% 14% 2	1890
	21st to end	Day	18% 54% 6% 15% 6% 1	1890
December	1st to 10th	Day	25% 35% 11% 21% 8%	2684
	11th to 20th	Day	29% 30% 9% 14% 15% 2	3066
	21st to end	Day	36% 28% 4 17% 12% 3	4048
January	1st to 10th	Night	32% 21% 8% 21% 16% 2	8234
	11th to 20th	Night	33% 21% 9% 17% 15% 5%	8280
	21st to end	Night	38% 23% 6% 16% 14% 3	8840
February	1st to 10th	Night	19% 59% 5% 11% 5% 1	2635
	11th to 20th	Night	19% 57% 2 11% 9% 2	2460
	21st to end	Night	20% 58% 3 9% 6% 2	2076
March	1st to 10th	Night	36% 29% 7% 13% 9% 7%	5399
	11th to 20th	Night	32% 30% 9% 18% 8% 3	5304
	21st to end	Night	37% 30% 4 8% 18% 4	4962
April	1st to 10th	Night	20% 62% 3 8% 6% 1	2000
	11th to 20th	Night	16% 62% 5% 8% 8% 1	1975
	21st to end	Night	18% 61% 3 9% 8% 1	1900
May	1st to 10th	Night	43% 30% 11% 9% 5% 1	4060
	11th to 20th	Night	40% 31% 10% 11% 7% 2	3862
	21st to end	Night	39% 31% 8% 14% 6% 1	3927
June	1st to 10th	Night	17% 61% 2 10% 9% 1	1600
	11th to 20th	Night	15% 62% 5% 11% 6%	1600
	21st to end	Night	15% 61% 3 11% 8% 1	1600
July	1st to 10th	Night	37% 29% 8% 17% 8% 1	3560
	11th to 20th	Night	38% 29% 12% 14% 7%	3552
	21st to end	Night	31% 27% 10% 19% 13%	3809
August	1st to 10th	Night	37% 37% 9% 10% 5% 1	2755
	11th to 20th	Night	26% 38% 10% 20% 5%	3226
	21st to end	Night	13% 37% 9% 26% 15% 1	3586
September	1st to 10th	Night	16% 57% 5% 14% 7% 1	2000
	11th to 20th	Night	15% 56% 4 10% 12% 2	2143
	21st to end	Night	24% 57% 3 9% 6% 1	2200
October	1st to 10th	Night	23% 38% 7% 17% 13% 2	3619
	11th to 20th	Night	13% 36% 5% 18% 26% 3	3921
	21st to end	Night	16% 36% 9% 20% 17% 2	4610
November	1st to 10th	Night	19% 53% 5% 12% 10% 1	2667
	11th to 20th	Night	17% 54% 4 10% 11% 4	2730
	21st to end	Night	17% 54% 6% 15% 7% 1	2730
December	1st to 10th	Night	27% 35% 8% 22% 7% 1	4714
	11th to 20th	Night	34% 30% 5% 17% 12% 2	5348
	21st to end	Night	34% 27% 7% 15% 14% 3	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	19% 12% 40% 19% 10% 1	220
	11th to 20th	Day	18% 16% 38% 23% 5%	220
	21st to end	Day	20% 13% 33% 23% 9% 2	281
February	1st to 10th	Day	21% 10% 36% 26% 6% 1	424
	11th to 20th	Day	22% 9% 37% 27% 4	536
	21st to end	Day	23% 8% 34% 27% 8% 1	446
March	1st to 10th	Day	18% 8% 31% 33% 8% 1	508
	11th to 20th	Day	18% 5% 34% 33% 9% 1	500
	21st to end	Day	21% 5% 32% 30% 9% 3	550
April	1st to 10th	Day	22% 7% 28% 30% 12% 2	500
	11th to 20th	Day	21% 4 25% 34% 14% 2	492
	21st to end	Day	23% 4 21% 35% 14% 3	500
May	1st to 10th	Day	26% 3 22% 32% 14% 3	503
	11th to 20th	Day	20% 3 18% 33% 22% 4	527
	21st to end	Day	19% 2 10% 28% 27% 13%	573
June	1st to 10th	Day	17% 1 13% 35% 27% 8%	530
	11th to 20th	Day	15% 2 15% 33% 28% 7%	530
	21st to end	Day	13% 2 12% 35% 30% 9%	530
July	1st to 10th	Day	13% 3 8% 28% 34% 14%	525
	11th to 20th	Day	10% 2 8% 28% 38% 15%	524
	21st to end	Day	13% 1 9% 36% 35% 7%	576
August	1st to 10th	Day	12% 2 9% 30% 34% 14%	526
	11th to 20th	Day	13% 3 7% 31% 34% 12%	519
	21st to end	Day	11% 1 11% 35% 28% 14%	583
September	1st to 10th	Day	18% 2 18% 24% 24% 15%	530
	11th to 20th	Day	14% 2 12% 31% 28% 13%	530
	21st to end	Day	20% 2 18% 33% 21% 5%	530
October	1st to 10th	Day	24% 5% 15% 25% 21% 11%	530
	11th to 20th	Day	15% 7% 29% 26% 19% 5%	524
	21st to end	Day	21% 7% 27% 26% 14% 3	462
November	1st to 10th	Day	15% 9% 25% 29% 17% 4	425
	11th to 20th	Day	18% 13% 32% 26% 10%	430
	21st to end	Day	18% 14% 31% 23% 12% 1	430
December	1st to 10th	Day	18% 11% 35% 23% 13%	224
	11th to 20th	Day	24% 14% 33% 24% 5% 1	220
	21st to end	Day	23% 9% 35% 22% 9% 2	242
January	1st to 10th	Night	20% 14% 40% 20% 6%	840
	11th to 20th	Night	26% 14% 33% 23% 4	840
	21st to end	Night	20% 14% 39% 23% 4	924
February	1st to 10th	Night	21% 11% 37% 27% 4	840
	11th to 20th	Night	24% 11% 41% 22% 2	823
	21st to end	Night	24% 10% 37% 24% 6%	692
March	1st to 10th	Night	21% 10% 36% 26% 7%	809
	11th to 20th	Night	20% 8% 37% 28% 7% 1	800
	21st to end	Night	23% 6% 35% 27% 9% 1	880
April	1st to 10th	Night	23% 5% 32% 30% 9%	800
	11th to 20th	Night	22% 4 29% 32% 12%	791
	21st to end	Night	22% 4 28% 35% 10% 1	700
May	1st to 10th	Night	26% 4 22% 33% 15% 2	600
	11th to 20th	Night	24% 2 25% 35% 12% 1	524
	21st to end	Night	22% 3 13% 36% 25% 2	433
June	1st to 10th	Night	19% 2 17% 38% 21% 3	400
	11th to 20th	Night	17% 3 12% 43% 23% 3	400
	21st to end	Night	13% 3 16% 43% 24% 2	400
July	1st to 10th	Night	11% 4 12% 42% 28% 3	390
	11th to 20th	Night	12% 2 12% 39% 32% 4	388
	21st to end	Night	14% 2 12% 46% 24% 3	438
August	1st to 10th	Night	10% 1 12% 45% 28% 3	499
	11th to 20th	Night	14% 2 11% 36% 33% 5%	789
	21st to end	Night	13% 2 13% 36% 29% 6%	880
September	1st to 10th	Night	15% 2 20% 32% 25% 5%	800
	11th to 20th	Night	16% 2 14% 37% 23% 8%	800
	21st to end	Night	21% 3 20% 33% 19% 4	800
October	1st to 10th	Night	21% 8% 22% 27% 17% 5%	800
	11th to 20th	Night	20% 9% 26% 29% 14% 1	800
	21st to end	Night	25% 7% 30% 26% 11% 1	880
November	1st to 10th	Night	16% 8% 31% 29% 13% 2	820
	11th to 20th	Night	22% 13% 32% 23% 10%	840
	21st to end	Night	17% 15% 33% 27% 8% 1	840
December	1st to 10th	Night	23% 14% 32% 23% 6% 1	840
	11th to 20th	Night	24% 13% 34% 24% 5%	840
	21st to end	Night	24% 12% 35% 25% 4	924

Page generated at 2026-02-28 01:40:25. Version ac07

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