Memorial Field of Flushing
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Memorial Field of Flushing clear sky chart from 2005-11-06 to 2025-11-18.

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% 7% 2 6% 4 4 4 3 6% 8% 40%	126854
	Night	17% 7% 2 6% 4 4 4 3 5% 6% 42%	123536
Transparency	Day	40% 7% 13% 22% 16% 2	130381
	Night	41% 6% 12% 22% 17% 3	128096
Seeing	Day	19% 13% 31% 23% 10% 3	16358
	Night	20% 11% 32% 28% 9% 1	25466

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% 6% 2 4 3 3 3 3 5% 6% 52%	3597
	11th to 20th	Day	14% 8% 2 6% 4 4 4 3 4 6% 43%	3570
	21st to end	Day	18% 10% 4 7% 4 4 4 3 4 4 39%	4280
February	1st to 10th	Day	16% 8% 3 6% 4 3 4 3 5% 7% 39%	1827
	11th to 20th	Day	15% 7% 3 7% 4 4 4 3 4 6% 44%	1948
	21st to end	Day	20% 7% 2 6% 4 3 4 3 5% 6% 39%	1650
March	1st to 10th	Day	22% 6% 2 5% 3 3 3 3 4 6% 42%	4476
	11th to 20th	Day	12% 7% 2 6% 4 4 5% 4 6% 8% 42%	4740
	21st to end	Day	18% 6% 2 6% 4 4 4 3 5% 6% 43%	5960
April	1st to 10th	Day	18% 8% 3 5% 4 3 4 4 5% 7% 38%	2400
	11th to 20th	Day	17% 6% 2 6% 4 5% 4 3 5% 8% 41%	2374
	21st to end	Day	18% 6% 2 4 4 4 5% 3 6% 7% 40%	2436
May	1st to 10th	Day	27% 8% 2 5% 4 4 4 3 5% 8% 28%	5886
	11th to 20th	Day	23% 9% 3 6% 4 3 4 3 5% 6% 34%	6221
	21st to end	Day	22% 6% 2 5% 3 4 4 4 6% 8% 35%	6949
June	1st to 10th	Day	16% 6% 2 5% 4 4 5% 4 7% 9% 37%	2800
	11th to 20th	Day	16% 6% 2 6% 4 4 4 4 5% 8% 38%	2800
	21st to end	Day	11% 6% 2 6% 5% 5% 4 4 7% 10% 41%	2800
July	1st to 10th	Day	10% 7% 2 7% 5% 5% 6% 5% 6% 10% 37%	6360
	11th to 20th	Day	11% 7% 3 7% 5% 5% 5% 5% 8% 11% 33%	6360
	21st to end	Day	13% 6% 2 6% 4 4 5% 4 6% 9% 39%	6926
August	1st to 10th	Day	19% 6% 2 6% 4 4 5% 4 7% 9% 33%	4294
	11th to 20th	Day	13% 5% 2 6% 4 5% 5% 4 7% 8% 41%	3850
	21st to end	Day	9% 5% 2 6% 4 4 4 4 6% 9% 48%	4312
September	1st to 10th	Day	14% 5% 2 5% 4 5% 4 3 5% 7% 46%	2400
	11th to 20th	Day	12% 5% 3 4 3 4 4 3 5% 8% 50%	2301
	21st to end	Day	18% 6% 3 6% 4 4 4 3 6% 6% 40%	2200
October	1st to 10th	Day	20% 6% 1 6% 3 4 3 3 5% 6% 43%	2109
	11th to 20th	Day	16% 5% 2 5% 4 3 4 4 5% 6% 47%	2000
	21st to end	Day	19% 5% 2 5% 3 3 4 3 5% 6% 44%	2028
November	1st to 10th	Day	13% 6% 2 6% 3 2 3 2 5% 5% 52%	1851
	11th to 20th	Day	16% 5% 2 5% 3 4 4 3 5% 6% 48%	1863
	21st to end	Day	16% 7% 2 4 4 4 3 4 5% 7% 45%	1740
December	1st to 10th	Day	16% 7% 2 5% 4 3 4 3 4 7% 46%	2600
	11th to 20th	Day	22% 8% 2 5% 2 2 3 2 4 6% 46%	2986
	21st to end	Day	17% 8% 2 6% 5% 4 4 3 5% 6% 39%	3960
January	1st to 10th	Night	14% 6% 2 5% 3 3 3 3 5% 6% 50%	6349
	11th to 20th	Night	15% 8% 2 6% 3 3 3 3 4 5% 47%	6315
	21st to end	Night	18% 9% 2 6% 3 4 4 4 4 6% 39%	6674
February	1st to 10th	Night	18% 8% 3 6% 5% 4 4 3 4 6% 41%	2571
	11th to 20th	Night	18% 8% 3 6% 4 4 3 3 4 5% 41%	2338
	21st to end	Night	20% 7% 2 5% 4 3 4 3 4 5% 42%	1980
March	1st to 10th	Night	19% 9% 3 5% 3 3 3 2 5% 5% 43%	5364
	11th to 20th	Night	14% 10% 3 6% 4 3 4 3 5% 5% 43%	5218
	21st to end	Night	18% 8% 3 7% 4 3 4 3 5% 5% 39%	4972
April	1st to 10th	Night	19% 6% 3 7% 5% 4 4 4 5% 6% 37%	2000
	11th to 20th	Night	19% 8% 3 6% 3 4 4 4 5% 7% 39%	1975
	21st to end	Night	19% 6% 2 6% 3 3 4 4 4 7% 43%	1962
May	1st to 10th	Night	26% 10% 4 7% 4 4 3 3 4 7% 27%	4054
	11th to 20th	Night	24% 9% 3 6% 4 3 3 3 4 5% 35%	3713
	21st to end	Night	22% 8% 3 6% 4 4 3 3 5% 7% 35%	3926
June	1st to 10th	Night	17% 8% 2 4 4 5% 3 4 6% 9% 40%	1600
	11th to 20th	Night	14% 7% 3 6% 4 4 4 4 6% 9% 39%	1600
	21st to end	Night	11% 5% 2 6% 5% 5% 6% 4 7% 10% 40%	1600
July	1st to 10th	Night	10% 7% 3 8% 6% 6% 5% 5% 6% 9% 35%	3600
	11th to 20th	Night	14% 10% 3 7% 5% 5% 5% 4 6% 9% 32%	3600
	21st to end	Night	14% 6% 2 6% 4 4 4 4 6% 8% 42%	3926
August	1st to 10th	Night	23% 6% 2 6% 4 4 4 5% 6% 7% 32%	2820
	11th to 20th	Night	14% 7% 2 7% 5% 4 4 4 7% 7% 39%	3197
	21st to end	Night	9% 5% 2 4 4 3 5% 4 5% 7% 52%	3586
September	1st to 10th	Night	13% 6% 2 7% 5% 4 5% 4 5% 6% 43%	2000
	11th to 20th	Night	12% 5% 2 5% 3 3 2 3 4 7% 51%	2097
	21st to end	Night	18% 6% 3 6% 4 4 3 3 4 7% 42%	2200
October	1st to 10th	Night	18% 5% 3 6% 4 3 3 3 4 7% 43%	2289
	11th to 20th	Night	15% 4 2 5% 3 4 4 2 5% 6% 50%	2400
	21st to end	Night	19% 8% 2 5% 4 3 3 2 4 6% 44%	2810
November	1st to 10th	Night	12% 6% 2 5% 4 4 3 3 4 6% 51%	2667
	11th to 20th	Night	19% 6% 2 5% 2 3 3 3 4 5% 49%	2692
	21st to end	Night	15% 6% 2 5% 4 4 3 4 5% 6% 46%	2657
December	1st to 10th	Night	17% 7% 2 5% 3 3 3 3 5% 5% 47%	4580
	11th to 20th	Night	26% 6% 2 4 3 3 3 2 4 5% 43%	5208
	21st to end	Night	19% 9% 2 6% 3 4 4 3 4 5% 41%	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	32% 4 10% 31% 20% 3	3598
	11th to 20th	Day	40% 5% 11% 22% 17% 5%	3600
	21st to end	Day	48% 4 10% 23% 13% 1	4280
February	1st to 10th	Day	44% 5% 14% 23% 13% 1	1827
	11th to 20th	Day	42% 4 9% 25% 17% 2	1957
	21st to end	Day	45% 4 12% 21% 15% 3	1650
March	1st to 10th	Day	41% 6% 11% 20% 14% 8%	4479
	11th to 20th	Day	36% 7% 15% 27% 11% 3	4740
	21st to end	Day	42% 6% 10% 13% 24% 5%	5960
April	1st to 10th	Day	44% 5% 12% 19% 16% 4	2400
	11th to 20th	Day	42% 5% 13% 21% 17% 3	2374
	21st to end	Day	41% 6% 12% 21% 17% 4	2436
May	1st to 10th	Day	53% 6% 16% 14% 10% 1	5897
	11th to 20th	Day	48% 6% 11% 19% 14% 2	6225
	21st to end	Day	43% 7% 13% 22% 14% 1	6949
June	1st to 10th	Day	40% 9% 14% 21% 15% 2	2800
	11th to 20th	Day	42% 8% 13% 24% 12% 2	2800
	21st to end	Day	37% 9% 16% 22% 16% 1	2800
July	1st to 10th	Day	42% 10% 13% 21% 14% 1	6290
	11th to 20th	Day	39% 10% 19% 21% 10% 1	6285
	21st to end	Day	39% 8% 13% 20% 19% 2	6728
August	1st to 10th	Day	45% 8% 15% 22% 9% 1	4280
	11th to 20th	Day	36% 8% 14% 29% 11% 1	3886
	21st to end	Day	31% 8% 13% 27% 20% 2	4312
September	1st to 10th	Day	37% 7% 13% 23% 19% 3	2400
	11th to 20th	Day	32% 6% 12% 24% 24% 2	2301
	21st to end	Day	44% 6% 11% 17% 18% 3	2200
October	1st to 10th	Day	34% 7% 11% 18% 23% 6%	3434
	11th to 20th	Day	26% 5% 11% 23% 30% 5%	3240
	21st to end	Day	28% 4 14% 26% 25% 3	3253
November	1st to 10th	Day	35% 4 13% 22% 23% 3	1851
	11th to 20th	Day	38% 4 10% 23% 22% 4	1863
	21st to end	Day	39% 5% 14% 30% 11% 2	1740
December	1st to 10th	Day	39% 5% 15% 28% 12% 1	2600
	11th to 20th	Day	42% 3 13% 22% 17% 2	2986
	21st to end	Day	44% 6% 9% 23% 15% 3	3960
January	1st to 10th	Night	35% 4 9% 25% 23% 4	6349
	11th to 20th	Night	39% 4 14% 22% 16% 5%	6360
	21st to end	Night	45% 4 10% 20% 17% 4	6674
February	1st to 10th	Night	45% 5% 13% 24% 12% 2	2571
	11th to 20th	Night	45% 5% 9% 19% 17% 5%	2340
	21st to end	Night	44% 4 9% 23% 17% 3	1980
March	1st to 10th	Night	43% 4 10% 21% 13% 9%	5374
	11th to 20th	Night	40% 6% 15% 23% 12% 4	5219
	21st to end	Night	46% 5% 7% 14% 23% 5%	4972
April	1st to 10th	Night	46% 6% 10% 18% 16% 4	2000
	11th to 20th	Night	45% 6% 10% 18% 20% 2	1975
	21st to end	Night	42% 6% 10% 20% 19% 4	1962
May	1st to 10th	Night	56% 6% 13% 13% 10% 1	4060
	11th to 20th	Night	50% 6% 13% 14% 14% 2	3714
	21st to end	Night	48% 5% 14% 21% 11% 2	3927
June	1st to 10th	Night	41% 8% 9% 20% 20% 1	1600
	11th to 20th	Night	40% 7% 14% 26% 11% 1	1600
	21st to end	Night	37% 8% 14% 24% 15% 2	1600
July	1st to 10th	Night	46% 8% 13% 20% 12% 2	3560
	11th to 20th	Night	47% 9% 14% 20% 9%	3552
	21st to end	Night	37% 8% 15% 21% 18% 1	3809
August	1st to 10th	Night	50% 8% 16% 16% 10% 1	2810
	11th to 20th	Night	41% 8% 13% 27% 10% 1	3227
	21st to end	Night	29% 7% 12% 32% 18% 1	3586
September	1st to 10th	Night	40% 8% 10% 23% 19% 1	2000
	11th to 20th	Night	33% 5% 11% 24% 23% 3	2097
	21st to end	Night	42% 5% 10% 21% 20% 2	2200
October	1st to 10th	Night	37% 6% 12% 23% 20% 3	3744
	11th to 20th	Night	24% 4 10% 27% 30% 4	3899
	21st to end	Night	30% 4 13% 29% 22% 2	4535
November	1st to 10th	Night	35% 5% 12% 23% 21% 4	2667
	11th to 20th	Night	39% 4 8% 23% 21% 5%	2692
	21st to end	Night	38% 5% 13% 28% 15% 2	2657
December	1st to 10th	Night	39% 4 12% 30% 13% 2	4580
	11th to 20th	Night	46% 4 10% 22% 15% 3	5208
	21st to end	Night	44% 6% 10% 19% 17% 3	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	23% 28% 30% 15% 5% 1	200
	11th to 20th	Day	20% 30% 35% 12% 3	200
	21st to end	Day	19% 21% 40% 12% 6% 1	290
February	1st to 10th	Day	26% 21% 37% 14% 2	327
	11th to 20th	Day	26% 19% 38% 16% 2	496
	21st to end	Day	24% 20% 36% 16% 4	414
March	1st to 10th	Day	23% 22% 32% 19% 4	500
	11th to 20th	Day	18% 21% 39% 16% 6% 1	500
	21st to end	Day	25% 21% 34% 15% 5% 1	550
April	1st to 10th	Day	25% 21% 34% 13% 7% 1	500
	11th to 20th	Day	23% 17% 35% 16% 8% 1	492
	21st to end	Day	24% 15% 35% 20% 5% 1	500
May	1st to 10th	Day	29% 15% 32% 18% 6% 2	503
	11th to 20th	Day	21% 13% 33% 24% 8% 1	527
	21st to end	Day	20% 7% 29% 27% 15% 3	573
June	1st to 10th	Day	17% 9% 30% 29% 12% 3	530
	11th to 20th	Day	16% 11% 32% 29% 10% 2	530
	21st to end	Day	13% 8% 31% 31% 16% 2	530
July	1st to 10th	Day	12% 5% 26% 35% 17% 5%	525
	11th to 20th	Day	9% 5% 26% 35% 21% 5%	524
	21st to end	Day	13% 7% 29% 33% 16% 2	576
August	1st to 10th	Day	12% 6% 24% 35% 16% 6%	526
	11th to 20th	Day	14% 5% 21% 36% 19% 5%	519
	21st to end	Day	11% 6% 28% 34% 15% 6%	583
September	1st to 10th	Day	17% 6% 29% 25% 17% 6%	530
	11th to 20th	Day	13% 4 28% 30% 15% 9%	530
	21st to end	Day	22% 10% 28% 24% 11% 5%	530
October	1st to 10th	Day	22% 9% 26% 23% 15% 4	530
	11th to 20th	Day	19% 14% 32% 22% 10% 2	530
	21st to end	Day	23% 12% 34% 21% 8% 2	487
November	1st to 10th	Day	14% 15% 35% 22% 12% 2	425
	11th to 20th	Day	21% 20% 32% 21% 5%	421
	21st to end	Day	19% 17% 36% 21% 6% 1	340
December	1st to 10th	Day	23% 20% 37% 15% 7%	200
	11th to 20th	Day	30% 25% 32% 10% 4	200
	21st to end	Day	24% 18% 38% 11% 9%	220
January	1st to 10th	Night	20% 17% 41% 19% 4	800
	11th to 20th	Night	25% 16% 33% 23% 3	800
	21st to end	Night	19% 16% 41% 21% 3	880
February	1st to 10th	Night	22% 14% 38% 24% 2	800
	11th to 20th	Night	23% 17% 41% 18% 1	783
	21st to end	Night	22% 17% 36% 20% 4	660
March	1st to 10th	Night	22% 15% 37% 21% 4	800
	11th to 20th	Night	22% 13% 39% 21% 4 1	800
	21st to end	Night	21% 14% 38% 22% 4	880
April	1st to 10th	Night	22% 16% 36% 21% 5%	800
	11th to 20th	Night	22% 13% 34% 25% 6%	791
	21st to end	Night	20% 12% 34% 27% 6% 1	762
May	1st to 10th	Night	24% 11% 35% 24% 7% 1	600
	11th to 20th	Night	22% 9% 36% 27% 6%	454
	21st to end	Night	21% 6% 19% 39% 14% 2	433
June	1st to 10th	Night	19% 5% 28% 35% 13% 1	400
	11th to 20th	Night	15% 6% 24% 40% 15%	400
	21st to end	Night	10% 5% 22% 49% 13% 1	400
July	1st to 10th	Night	12% 4 21% 45% 18% 1	390
	11th to 20th	Night	14% 3 19% 43% 20% 2	388
	21st to end	Night	13% 4 21% 44% 18% 1	438
August	1st to 10th	Night	14% 2 21% 42% 20% 2	528
	11th to 20th	Night	14% 4 19% 37% 24% 1	790
	21st to end	Night	14% 4 21% 37% 23% 2	880
September	1st to 10th	Night	15% 4 26% 34% 19% 2	800
	11th to 20th	Night	15% 4 25% 33% 20% 4	800
	21st to end	Night	20% 6% 25% 32% 16% 2	800
October	1st to 10th	Night	21% 8% 27% 25% 16% 3	800
	11th to 20th	Night	18% 12% 29% 31% 10% 1	800
	21st to end	Night	23% 11% 35% 24% 7%	880
November	1st to 10th	Night	15% 11% 35% 28% 11% 1	820
	11th to 20th	Night	21% 16% 32% 23% 7%	829
	21st to end	Night	19% 15% 34% 26% 6% 1	800
December	1st to 10th	Night	25% 14% 34% 21% 6% 1	800
	11th to 20th	Night	24% 15% 35% 24% 4	800
	21st to end	Night	23% 14% 37% 24% 3	880

Page generated at 2025-11-15 00:55:58. Version ac07

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