Shinnecock Hills Golf Club
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shinnecock Hills Golf Club clear sky chart from 2005-11-06 to 2026-02-01.

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	16% 8% 2 6% 4 4 4 3 5% 7% 42%	127222
	Night	18% 8% 3 6% 4 4 4 3 5% 6% 40%	124788
Transparency	Day	43% 3 13% 24% 16% 2	130766
	Night	45% 3 11% 23% 16% 3	129331
Seeing	Day	20% 11% 29% 24% 12% 3	16629
	Night	21% 11% 27% 27% 12% 2	25762

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	13% 7% 3 5% 4 4 4 3 5% 6% 47%	3677
	11th to 20th	Day	15% 8% 2 5% 3 3 3 3 4 6% 46%	3650
	21st to end	Day	18% 9% 4 6% 4 4 3 3 4 4 40%	4160
February	1st to 10th	Day	18% 7% 2 6% 4 4 5% 3 6% 7% 37%	1921
	11th to 20th	Day	16% 6% 2 6% 5% 4 4 3 5% 6% 43%	1948
	21st to end	Day	20% 8% 3 6% 3 3 3 3 6% 5% 39%	1650
March	1st to 10th	Day	20% 8% 2 5% 3 3 3 2 4 6% 44%	4476
	11th to 20th	Day	12% 9% 2 5% 4 3 4 3 6% 7% 46%	4654
	21st to end	Day	19% 9% 3 6% 3 4 4 3 5% 6% 39%	5942
April	1st to 10th	Day	18% 8% 2 5% 4 4 3 3 6% 6% 41%	2400
	11th to 20th	Day	18% 6% 2 5% 4 3 4 3 4 7% 44%	2374
	21st to end	Day	18% 6% 2 4 3 4 4 4 6% 6% 42%	2520
May	1st to 10th	Day	27% 10% 3 6% 3 3 3 3 5% 7% 30%	5886
	11th to 20th	Day	21% 10% 3 6% 4 3 3 3 4 6% 39%	5985
	21st to end	Day	19% 8% 2 6% 3 3 3 3 6% 9% 37%	6949
June	1st to 10th	Day	17% 6% 1 6% 4 3 4 4 6% 9% 40%	2800
	11th to 20th	Day	13% 7% 2 6% 4 4 4 4 6% 8% 41%	2800
	21st to end	Day	12% 6% 2 5% 4 4 3 4 7% 9% 44%	2800
July	1st to 10th	Day	13% 9% 3 7% 4 4 4 4 6% 9% 37%	6360
	11th to 20th	Day	12% 8% 3 7% 4 4 5% 5% 7% 10% 35%	6360
	21st to end	Day	15% 7% 2 6% 4 3 4 4 6% 7% 44%	6926
August	1st to 10th	Day	16% 7% 2 6% 4 4 4 4 6% 9% 37%	4307
	11th to 20th	Day	11% 6% 2 6% 4 4 5% 4 6% 8% 46%	3889
	21st to end	Day	7% 3 1 4 4 4 5% 4 6% 9% 53%	4312
September	1st to 10th	Day	14% 6% 2 6% 4 3 3 3 5% 7% 48%	2400
	11th to 20th	Day	10% 6% 1 5% 3 3 3 3 5% 7% 53%	2237
	21st to end	Day	18% 7% 2 7% 4 3 5% 4 5% 6% 39%	2200
October	1st to 10th	Day	20% 5% 2 4 3 3 3 2 4 7% 46%	2200
	11th to 20th	Day	15% 5% 2 5% 3 2 4 4 6% 7% 47%	1980
	21st to end	Day	18% 6% 3 5% 4 4 4 3 5% 7% 41%	1980
November	1st to 10th	Day	15% 6% 2 4 3 4 4 3 4 5% 49%	1851
	11th to 20th	Day	15% 6% 2 5% 4 3 3 3 5% 7% 47%	1890
	21st to end	Day	17% 9% 2 5% 4 3 3 4 5% 6% 43%	1890
December	1st to 10th	Day	14% 8% 3 7% 4 3 3 3 4 7% 43%	2734
	11th to 20th	Day	21% 9% 2 5% 3 2 2 2 3 5% 46%	3066
	21st to end	Day	19% 10% 3 7% 4 4 3 3 4 5% 38%	4048
January	1st to 10th	Night	14% 6% 2 5% 3 3 3 3 5% 7% 48%	6489
	11th to 20th	Night	15% 8% 3 7% 4 3 4 3 4 4 44%	6455
	21st to end	Night	17% 9% 3 7% 5% 4 4 4 5% 6% 35%	7036
February	1st to 10th	Night	17% 9% 3 7% 4 4 4 3 5% 6% 37%	2478
	11th to 20th	Night	19% 8% 2 5% 4 3 4 3 5% 8% 37%	2338
	21st to end	Night	21% 7% 2 6% 4 4 4 3 4 6% 39%	1980
March	1st to 10th	Night	21% 10% 2 5% 3 3 3 3 4 6% 40%	5364
	11th to 20th	Night	16% 11% 3 6% 4 3 4 3 5% 5% 41%	5303
	21st to end	Night	21% 9% 3 5% 3 4 4 3 5% 6% 38%	4972
April	1st to 10th	Night	20% 8% 2 5% 4 4 4 3 5% 6% 39%	2000
	11th to 20th	Night	18% 7% 2 6% 4 4 3 3 4 6% 42%	1975
	21st to end	Night	20% 8% 3 6% 4 2 4 3 4 6% 40%	1878
May	1st to 10th	Night	24% 13% 5% 7% 4 3 3 3 5% 6% 28%	4054
	11th to 20th	Night	25% 10% 2 6% 3 4 3 3 5% 7% 31%	3951
	21st to end	Night	22% 9% 3 7% 4 4 4 4 6% 8% 30%	3926
June	1st to 10th	Night	18% 8% 3 6% 4 3 4 4 4 7% 39%	1600
	11th to 20th	Night	18% 7% 2 5% 4 4 3 4 6% 9% 40%	1600
	21st to end	Night	12% 6% 3 6% 5% 5% 5% 4 6% 9% 37%	1600
July	1st to 10th	Night	15% 12% 4 8% 5% 3 4 4 5% 8% 32%	3600
	11th to 20th	Night	16% 11% 3 7% 4 4 5% 4 7% 9% 30%	3600
	21st to end	Night	14% 7% 2 6% 4 4 4 3 5% 8% 41%	3926
August	1st to 10th	Night	22% 7% 2 6% 5% 4 5% 4 6% 7% 31%	2808
	11th to 20th	Night	10% 6% 3 7% 4 5% 5% 5% 6% 9% 41%	3156
	21st to end	Night	8% 4 1 5% 3 4 4 3 6% 9% 55%	3586
September	1st to 10th	Night	14% 7% 2 5% 4 4 5% 5% 5% 6% 42%	2000
	11th to 20th	Night	13% 6% 2 4 3 3 3 2 5% 7% 50%	2162
	21st to end	Night	18% 8% 2 7% 5% 4 4 3 4 6% 39%	2200
October	1st to 10th	Night	19% 7% 3 6% 4 4 4 3 4 6% 41%	2200
	11th to 20th	Night	17% 6% 2 4 4 3 3 2 4 6% 48%	2415
	21st to end	Night	20% 8% 3 7% 4 3 3 3 4 6% 40%	2860
November	1st to 10th	Night	14% 7% 3 5% 4 4 3 4 4 6% 47%	2667
	11th to 20th	Night	19% 7% 2 4 4 4 3 3 5% 5% 44%	2730
	21st to end	Night	15% 5% 2 5% 5% 4 4 4 5% 9% 42%	2730
December	1st to 10th	Night	16% 8% 3 6% 4 3 4 3 5% 5% 43%	4651
	11th to 20th	Night	24% 8% 2 5% 3 3 3 3 4 5% 40%	5348
	21st to end	Night	18% 9% 3 6% 4 4 3 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	40% 2 7% 30% 19% 1	3678
	11th to 20th	Day	41% 3 11% 22% 17% 6%	3680
	21st to end	Day	49% 1 10% 23% 15% 1	4160
February	1st to 10th	Day	47% 3 15% 22% 12% 1	1921
	11th to 20th	Day	44% 3 9% 27% 16% 2	1957
	21st to end	Day	46% 3 12% 20% 15% 4	1650
March	1st to 10th	Day	43% 3 11% 18% 16% 9%	4479
	11th to 20th	Day	39% 2 14% 30% 14% 1	4654
	21st to end	Day	48% 2 8% 16% 21% 5%	5942
April	1st to 10th	Day	44% 4 10% 20% 19% 4	2400
	11th to 20th	Day	41% 4 10% 22% 20% 3	2374
	21st to end	Day	41% 4 9% 24% 18% 4	2520
May	1st to 10th	Day	56% 3 16% 15% 8% 1	5897
	11th to 20th	Day	50% 2 12% 21% 13% 2	5989
	21st to end	Day	47% 3 11% 26% 13% 1	6949
June	1st to 10th	Day	42% 4 13% 24% 15% 1	2800
	11th to 20th	Day	40% 5% 14% 26% 14% 1	2800
	21st to end	Day	37% 5% 16% 26% 15% 1	2800
July	1st to 10th	Day	46% 5% 14% 19% 14% 1	6290
	11th to 20th	Day	46% 4 18% 23% 9% 1	6285
	21st to end	Day	40% 3 12% 26% 18% 1	6728
August	1st to 10th	Day	46% 4 17% 24% 10%	4293
	11th to 20th	Day	38% 4 16% 32% 10% 1	3926
	21st to end	Day	29% 3 16% 31% 19% 1	4312
September	1st to 10th	Day	37% 5% 13% 24% 20% 1	2400
	11th to 20th	Day	33% 3 11% 27% 24% 2	2237
	21st to end	Day	46% 5% 9% 21% 18% 2	2200
October	1st to 10th	Day	35% 2 11% 23% 24% 5%	3590
	11th to 20th	Day	28% 2 12% 24% 31% 2	3196
	21st to end	Day	34% 3 14% 28% 19% 2	3180
November	1st to 10th	Day	38% 3 15% 23% 19% 2	1851
	11th to 20th	Day	38% 3 12% 24% 19% 2	1890
	21st to end	Day	43% 3 13% 29% 10% 2	1890
December	1st to 10th	Day	43% 2 15% 27% 12% 1	2734
	11th to 20th	Day	45% 2 13% 20% 18% 3	3066
	21st to end	Day	51% 2 8% 22% 15% 2	4048
January	1st to 10th	Night	38% 2 9% 29% 20% 2	6489
	11th to 20th	Night	45% 2 11% 22% 16% 4	6500
	21st to end	Night	51% 1 10% 21% 14% 3	7036
February	1st to 10th	Night	48% 3 13% 23% 10% 2	2478
	11th to 20th	Night	47% 3 8% 24% 14% 3	2340
	21st to end	Night	48% 2 7% 24% 15% 4	1980
March	1st to 10th	Night	48% 2 11% 20% 13% 7%	5374
	11th to 20th	Night	46% 2 12% 24% 12% 3	5304
	21st to end	Night	50% 2 5% 14% 23% 5%	4972
April	1st to 10th	Night	47% 3 8% 20% 17% 4	2000
	11th to 20th	Night	44% 3 10% 20% 21% 2	1975
	21st to end	Night	46% 2 9% 22% 17% 5%	1878
May	1st to 10th	Night	59% 2 14% 14% 9% 1	4060
	11th to 20th	Night	55% 2 13% 17% 9% 4	3952
	21st to end	Night	54% 3 12% 21% 9% 1	3927
June	1st to 10th	Night	47% 4 10% 21% 16% 2	1600
	11th to 20th	Night	42% 4 14% 25% 14% 1	1600
	21st to end	Night	43% 5% 12% 25% 14% 1	1600
July	1st to 10th	Night	51% 5% 11% 21% 11% 1	3560
	11th to 20th	Night	51% 4 15% 21% 9% 1	3552
	21st to end	Night	42% 3 14% 25% 15% 1	3809
August	1st to 10th	Night	51% 5% 16% 19% 9% 1	2798
	11th to 20th	Night	39% 5% 16% 30% 9%	3185
	21st to end	Night	28% 4 14% 33% 20% 1	3586
September	1st to 10th	Night	43% 4 9% 26% 18% 2	2000
	11th to 20th	Night	35% 3 10% 26% 23% 3	2162
	21st to end	Night	48% 4 8% 20% 18% 3	2200
October	1st to 10th	Night	41% 2 10% 26% 18% 3	3590
	11th to 20th	Night	29% 2 9% 26% 31% 4	3938
	21st to end	Night	35% 2 13% 26% 22% 2	4610
November	1st to 10th	Night	40% 3 11% 24% 19% 3	2667
	11th to 20th	Night	43% 4 9% 23% 17% 4	2730
	21st to end	Night	40% 4 13% 29% 12% 1	2730
December	1st to 10th	Night	45% 2 12% 28% 12% 2	4651
	11th to 20th	Night	49% 2 9% 24% 14% 2	5348
	21st to end	Night	46% 2 10% 20% 18% 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	22% 21% 37% 15% 3 1	220
	11th to 20th	Day	25% 25% 34% 14% 3	220
	21st to end	Day	23% 20% 37% 13% 5% 1	267
February	1st to 10th	Day	24% 17% 38% 17% 4	421
	11th to 20th	Day	27% 21% 37% 14% 2	496
	21st to end	Day	26% 17% 35% 17% 3 1	414
March	1st to 10th	Day	21% 21% 35% 19% 4	500
	11th to 20th	Day	20% 15% 40% 19% 5% 1	500
	21st to end	Day	26% 14% 36% 17% 6% 1	550
April	1st to 10th	Day	26% 16% 34% 18% 6% 1	500
	11th to 20th	Day	24% 15% 32% 20% 8% 1	492
	21st to end	Day	24% 12% 32% 23% 6% 2	500
May	1st to 10th	Day	27% 12% 32% 20% 7% 2	503
	11th to 20th	Day	20% 8% 36% 26% 9% 1	527
	21st to end	Day	20% 6% 24% 30% 16% 5%	573
June	1st to 10th	Day	17% 5% 28% 32% 15% 3	530
	11th to 20th	Day	17% 5% 28% 31% 16% 4	530
	21st to end	Day	15% 4 25% 34% 18% 4	530
July	1st to 10th	Day	17% 3 21% 34% 21% 5%	525
	11th to 20th	Day	11% 5% 20% 34% 22% 8%	524
	21st to end	Day	14% 5% 23% 35% 19% 3	576
August	1st to 10th	Day	14% 3 20% 35% 21% 7%	526
	11th to 20th	Day	15% 2 19% 34% 22% 8%	519
	21st to end	Day	11% 3 26% 33% 17% 10%	583
September	1st to 10th	Day	20% 5% 21% 30% 16% 8%	530
	11th to 20th	Day	14% 4 26% 25% 19% 12%	530
	21st to end	Day	22% 6% 30% 24% 15% 3	530
October	1st to 10th	Day	22% 7% 24% 23% 16% 7%	530
	11th to 20th	Day	15% 13% 31% 21% 16% 3	513
	21st to end	Day	24% 11% 33% 20% 9% 3	462
November	1st to 10th	Day	16% 14% 32% 26% 11% 2	425
	11th to 20th	Day	19% 22% 30% 20% 8%	430
	21st to end	Day	22% 21% 27% 21% 8% 1	430
December	1st to 10th	Day	19% 23% 36% 14% 8%	261
	11th to 20th	Day	30% 25% 26% 15% 3	220
	21st to end	Day	26% 16% 33% 16% 7% 2	242
January	1st to 10th	Night	22% 23% 33% 17% 5%	840
	11th to 20th	Night	28% 19% 29% 20% 4	840
	21st to end	Night	20% 22% 34% 21% 2	924
February	1st to 10th	Night	23% 14% 38% 22% 3	801
	11th to 20th	Night	27% 20% 35% 15% 2	783
	21st to end	Night	25% 18% 33% 19% 5%	660
March	1st to 10th	Night	23% 16% 33% 22% 5%	800
	11th to 20th	Night	23% 12% 34% 24% 5% 2	800
	21st to end	Night	22% 13% 35% 22% 7% 1	880
April	1st to 10th	Night	26% 11% 31% 26% 6%	800
	11th to 20th	Night	21% 10% 31% 29% 8% 1	791
	21st to end	Night	21% 8% 32% 28% 9% 1	678
May	1st to 10th	Night	24% 7% 27% 29% 12% 2	600
	11th to 20th	Night	24% 7% 32% 30% 8% 1	562
	21st to end	Night	22% 2 18% 36% 20% 2	433
June	1st to 10th	Night	21% 3 24% 31% 19% 2	400
	11th to 20th	Night	22% 3 17% 37% 20% 2	400
	21st to end	Night	16% 4 17% 40% 21% 2	400
July	1st to 10th	Night	14% 2 14% 42% 25% 3	390
	11th to 20th	Night	13% 4 15% 39% 23% 5%	388
	21st to end	Night	14% 3 15% 44% 23% 2	438
August	1st to 10th	Night	11% 2 16% 44% 25% 2	529
	11th to 20th	Night	13% 3 15% 37% 27% 6%	761
	21st to end	Night	13% 4 14% 37% 26% 6%	880
September	1st to 10th	Night	16% 3 20% 33% 22% 6%	800
	11th to 20th	Night	16% 3 18% 32% 23% 8%	800
	21st to end	Night	22% 5% 21% 30% 18% 3	800
October	1st to 10th	Night	22% 8% 23% 25% 18% 5%	800
	11th to 20th	Night	22% 11% 26% 27% 13% 2	800
	21st to end	Night	24% 10% 31% 23% 10% 1	880
November	1st to 10th	Night	17% 11% 30% 26% 13% 2	820
	11th to 20th	Night	24% 20% 26% 21% 9% 1	840
	21st to end	Night	20% 20% 29% 24% 8% 1	840
December	1st to 10th	Night	25% 18% 29% 21% 5% 1	840
	11th to 20th	Night	24% 22% 29% 21% 4	840
	21st to end	Night	26% 16% 33% 20% 4	924

Page generated at 2026-01-29 01:21:41. Version ac07

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