Queens
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Queens clear sky chart from 2005-11-06 to 2024-01-13.

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	20% 8% 4 6% 5% 3 4 5% 5% 7% 32%	75036
	Night	21% 8% 3 6% 5% 3 4 5% 5% 7% 32%	74682
Transparency	Day	51% 8% 12% 18% 10% 1	74747
	Night	53% 7% 11% 18% 9% 1	74506
Seeing	Day	24% 10% 27% 28% 10% 1	16048
	Night	24% 10% 28% 27% 9% 1	23757

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	18% 12% 5% 9% 6% 5% 5% 5% 6% 7% 22%	1516
	11th to 20th	Day	22% 12% 5% 8% 5% 3 5% 4 7% 7% 21%	1591
	21st to end	Day	15% 9% 4 7% 7% 5% 5% 6% 8% 8% 27%	1782
February	1st to 10th	Day	20% 12% 5% 7% 6% 4 5% 6% 6% 7% 23%	1620
	11th to 20th	Day	18% 9% 5% 8% 6% 5% 7% 6% 5% 6% 25%	1573
	21st to end	Day	13% 10% 5% 7% 6% 4 5% 5% 6% 7% 31%	1377
March	1st to 10th	Day	19% 12% 5% 8% 6% 3 4 5% 5% 7% 27%	1976
	11th to 20th	Day	17% 9% 5% 7% 6% 3 5% 4 5% 7% 32%	1980
	21st to end	Day	17% 11% 5% 6% 6% 3 4 4 4 6% 34%	2178
April	1st to 10th	Day	24% 13% 5% 7% 6% 3 3 4 4 6% 27%	2115
	11th to 20th	Day	21% 9% 3 6% 4 3 4 3 6% 8% 35%	2223
	21st to end	Day	23% 7% 4 7% 5% 3 4 4 5% 6% 33%	2340
May	1st to 10th	Day	24% 10% 4 7% 6% 3 4 4 5% 7% 26%	2340
	11th to 20th	Day	22% 8% 3 5% 5% 3 4 4 4 7% 35%	2455
	21st to end	Day	20% 9% 3 6% 5% 3 4 4 5% 8% 32%	2724
June	1st to 10th	Day	24% 10% 4 5% 6% 3 4 4 4 8% 29%	2520
	11th to 20th	Day	21% 8% 3 7% 5% 3 4 4 5% 6% 35%	2604
	21st to end	Day	23% 7% 3 7% 5% 3 5% 5% 6% 7% 28%	2700
July	1st to 10th	Day	18% 7% 3 5% 5% 3 4 4 6% 11% 34%	2633
	11th to 20th	Day	16% 7% 4 7% 5% 3 5% 4 6% 9% 33%	2520
	21st to end	Day	19% 7% 4 6% 5% 3 4 5% 6% 8% 32%	2571
August	1st to 10th	Day	15% 6% 3 5% 6% 3 5% 5% 6% 9% 37%	2327
	11th to 20th	Day	16% 7% 2 6% 5% 3 5% 6% 6% 8% 37%	2304
	21st to end	Day	14% 6% 3 5% 5% 3 4 4 5% 8% 43%	2494
September	1st to 10th	Day	14% 6% 2 5% 5% 3 4 5% 5% 7% 45%	2160
	11th to 20th	Day	18% 6% 3 5% 4 2 4 5% 5% 6% 42%	2040
	21st to end	Day	19% 6% 2 5% 5% 3 3 4 4 6% 42%	1954
October	1st to 10th	Day	20% 5% 2 5% 5% 3 4 5% 4 7% 40%	1800
	11th to 20th	Day	20% 6% 2 5% 5% 3 5% 5% 6% 7% 35%	1800
	21st to end	Day	23% 7% 3 6% 5% 4 5% 5% 5% 6% 32%	1980
November	1st to 10th	Day	19% 10% 3 6% 6% 3 4 4 4 6% 35%	1590
	11th to 20th	Day	22% 8% 3 6% 6% 3 5% 5% 6% 8% 29%	1520
	21st to end	Day	21% 9% 4 7% 7% 4 5% 4 5% 7% 28%	1520
December	1st to 10th	Day	25% 10% 4 8% 7% 3 5% 5% 5% 7% 22%	1520
	11th to 20th	Day	31% 9% 4 6% 5% 3 4 6% 6% 6% 20%	1906
	21st to end	Day	23% 9% 5% 8% 6% 3 4 4 5% 7% 26%	2783
January	1st to 10th	Night	19% 12% 4 8% 7% 4 6% 5% 5% 7% 22%	2649
	11th to 20th	Night	20% 10% 4 8% 7% 4 5% 6% 6% 8% 22%	2409
	21st to end	Night	15% 10% 4 8% 6% 4 5% 7% 7% 8% 27%	2574
February	1st to 10th	Night	20% 10% 3 7% 7% 4 6% 5% 5% 7% 26%	2340
	11th to 20th	Night	18% 10% 3 7% 7% 4 6% 6% 7% 7% 24%	2273
	21st to end	Night	13% 8% 4 8% 6% 5% 5% 6% 5% 7% 33%	1876
March	1st to 10th	Night	18% 10% 3 6% 5% 4 5% 5% 5% 7% 32%	1971
	11th to 20th	Night	19% 9% 4 6% 6% 3 5% 5% 4 7% 31%	1979
	21st to end	Night	17% 10% 4 6% 6% 2 4 4 5% 6% 36%	2178
April	1st to 10th	Night	26% 10% 3 6% 5% 3 3 4 4 5% 30%	1844
	11th to 20th	Night	25% 7% 3 5% 4 3 4 4 4 6% 34%	1684
	21st to end	Night	24% 9% 3 6% 5% 3 4 4 4 6% 32%	1620
May	1st to 10th	Night	24% 10% 4 5% 6% 3 4 3 5% 6% 31%	1620
	11th to 20th	Night	24% 7% 3 6% 4 2 4 4 4 8% 33%	1436
	21st to end	Night	19% 9% 3 8% 5% 3 3 4 6% 7% 33%	1550
June	1st to 10th	Night	26% 8% 3 5% 4 3 3 5% 5% 7% 30%	1440
	11th to 20th	Night	22% 8% 3 6% 6% 3 4 4 4 5% 34%	1366
	21st to end	Night	26% 9% 4 6% 7% 3 4 3 5% 6% 28%	1260
July	1st to 10th	Night	19% 7% 3 5% 4 2 4 5% 6% 9% 35%	1304
	11th to 20th	Night	18% 9% 4 6% 6% 3 5% 6% 7% 7% 30%	1440
	21st to end	Night	19% 9% 4 5% 5% 3 4 4 5% 7% 34%	1742
August	1st to 10th	Night	15% 7% 3 6% 6% 2 3 3 5% 8% 43%	1612
	11th to 20th	Night	18% 8% 2 6% 5% 4 4 4 5% 7% 37%	1596
	21st to end	Night	15% 7% 2 6% 5% 3 3 4 5% 7% 42%	1861
September	1st to 10th	Night	14% 6% 3 5% 5% 3 5% 4 5% 9% 43%	1800
	11th to 20th	Night	18% 7% 2 5% 3 3 4 4 5% 6% 45%	1916
	21st to end	Night	21% 7% 3 5% 6% 3 3 4 4 7% 39%	2006
October	1st to 10th	Night	21% 5% 2 4 4 3 4 3 5% 7% 41%	2160
	11th to 20th	Night	18% 7% 2 5% 4 3 4 4 5% 7% 40%	2160
	21st to end	Night	24% 7% 2 5% 4 3 4 4 4 7% 36%	2376
November	1st to 10th	Night	20% 8% 3 5% 5% 3 4 4 5% 7% 37%	2483
	11th to 20th	Night	20% 7% 3 6% 6% 4 6% 5% 6% 7% 30%	2660
	21st to end	Night	20% 9% 3 6% 5% 3 6% 5% 5% 7% 31%	2660
December	1st to 10th	Night	24% 10% 4 9% 5% 3 5% 5% 5% 7% 23%	2660
	11th to 20th	Night	30% 9% 3 6% 5% 3 4 4 5% 6% 23%	3293
	21st to end	Night	25% 8% 3 6% 6% 3 5% 4 5% 6% 29%	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	62% 8% 12% 12% 6%	1517
	11th to 20th	Day	62% 9% 12% 14% 3	1591
	21st to end	Day	53% 8% 14% 19% 6%	1782
February	1st to 10th	Day	59% 8% 13% 13% 6% 1	1620
	11th to 20th	Day	59% 8% 12% 15% 6% 1	1581
	21st to end	Day	48% 9% 13% 19% 9% 2	1377
March	1st to 10th	Day	55% 6% 10% 18% 11% 1	1980
	11th to 20th	Day	46% 7% 15% 18% 13% 2	1980
	21st to end	Day	48% 6% 10% 21% 12% 3	2178
April	1st to 10th	Day	56% 5% 9% 16% 13% 2	2115
	11th to 20th	Day	47% 5% 13% 20% 13% 1	2223
	21st to end	Day	50% 6% 12% 18% 12% 2	2340
May	1st to 10th	Day	57% 6% 11% 16% 9% 1	2340
	11th to 20th	Day	48% 6% 11% 19% 14% 1	2459
	21st to end	Day	51% 9% 12% 19% 9% 1	2724
June	1st to 10th	Day	55% 7% 11% 18% 10%	2520
	11th to 20th	Day	51% 7% 10% 18% 12% 2	2604
	21st to end	Day	59% 8% 9% 13% 10% 1	2700
July	1st to 10th	Day	50% 10% 13% 16% 10% 2	2561
	11th to 20th	Day	53% 9% 12% 18% 7% 1	2444
	21st to end	Day	51% 12% 12% 18% 6% 1	2427
August	1st to 10th	Day	46% 10% 12% 19% 12% 1	2314
	11th to 20th	Day	44% 10% 16% 19% 10% 1	2304
	21st to end	Day	39% 8% 13% 24% 14% 1	2494
September	1st to 10th	Day	39% 7% 12% 24% 17% 2	2160
	11th to 20th	Day	43% 7% 10% 23% 16% 2	2040
	21st to end	Day	43% 7% 9% 23% 17% 1	1954
October	1st to 10th	Day	42% 7% 12% 26% 12% 2	1800
	11th to 20th	Day	45% 8% 13% 21% 12% 1	1800
	21st to end	Day	52% 7% 12% 19% 9% 1	1980
November	1st to 10th	Day	51% 6% 11% 22% 9% 1	1590
	11th to 20th	Day	53% 9% 12% 17% 8% 1	1520
	21st to end	Day	55% 7% 14% 18% 5% 1	1520
December	1st to 10th	Day	63% 7% 13% 12% 4	1520
	11th to 20th	Day	65% 8% 9% 11% 6%	1905
	21st to end	Day	58% 9% 14% 12% 5% 2	2783
January	1st to 10th	Night	64% 7% 11% 14% 4	2649
	11th to 20th	Night	62% 10% 12% 11% 5%	2409
	21st to end	Night	55% 10% 14% 15% 6%	2574
February	1st to 10th	Night	59% 9% 11% 13% 7% 1	2340
	11th to 20th	Night	57% 9% 12% 13% 8% 1	2276
	21st to end	Night	51% 9% 15% 16% 9% 1	1876
March	1st to 10th	Night	52% 7% 11% 18% 10% 2	1980
	11th to 20th	Night	53% 6% 12% 15% 12% 2	1980
	21st to end	Night	49% 5% 10% 20% 14% 2	2178
April	1st to 10th	Night	56% 5% 9% 14% 12% 4	1844
	11th to 20th	Night	50% 5% 11% 19% 14% 2	1684
	21st to end	Night	53% 4 10% 20% 12% 1	1620
May	1st to 10th	Night	55% 5% 9% 20% 10% 1	1620
	11th to 20th	Night	51% 6% 8% 22% 12% 1	1437
	21st to end	Night	53% 8% 11% 19% 9% 1	1551
June	1st to 10th	Night	57% 5% 10% 20% 8%	1440
	11th to 20th	Night	53% 5% 12% 16% 13% 1	1366
	21st to end	Night	61% 6% 10% 11% 11% 1	1260
July	1st to 10th	Night	48% 9% 13% 18% 11% 1	1267
	11th to 20th	Night	56% 9% 9% 18% 8% 1	1392
	21st to end	Night	52% 9% 11% 18% 7% 2	1646
August	1st to 10th	Night	44% 8% 11% 23% 13% 1	1600
	11th to 20th	Night	47% 10% 13% 19% 11% 1	1596
	21st to end	Night	43% 7% 13% 23% 13%	1861
September	1st to 10th	Night	41% 7% 10% 27% 14% 2	1800
	11th to 20th	Night	42% 6% 8% 25% 17% 2	1916
	21st to end	Night	47% 5% 8% 23% 15% 1	2006
October	1st to 10th	Night	44% 6% 12% 24% 13% 2	2160
	11th to 20th	Night	43% 7% 13% 27% 10%	2160
	21st to end	Night	50% 8% 10% 19% 12% 1	2376
November	1st to 10th	Night	50% 7% 13% 19% 10% 1	2483
	11th to 20th	Night	53% 9% 13% 17% 8%	2660
	21st to end	Night	54% 10% 15% 15% 6%	2660
December	1st to 10th	Night	63% 8% 11% 14% 4	2660
	11th to 20th	Night	66% 7% 8% 13% 5% 1	3295
	21st to end	Night	58% 7% 13% 16% 5%	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	28% 17% 32% 19% 4	370
	11th to 20th	Day	29% 14% 35% 18% 4	346
	21st to end	Day	20% 16% 35% 25% 3	374
February	1st to 10th	Day	26% 15% 36% 22% 1	340
	11th to 20th	Day	26% 21% 32% 19% 1	336
	21st to end	Day	16% 16% 41% 23% 4	300
March	1st to 10th	Day	23% 15% 37% 20% 4	420
	11th to 20th	Day	19% 17% 33% 24% 6% 1	420
	21st to end	Day	23% 12% 34% 23% 7% 1	462
April	1st to 10th	Day	31% 14% 30% 21% 5%	420
	11th to 20th	Day	23% 9% 36% 27% 5%	412
	21st to end	Day	24% 9% 27% 28% 11% 1	420
May	1st to 10th	Day	26% 9% 34% 25% 6% 1	423
	11th to 20th	Day	21% 7% 29% 31% 11% 1	601
	21st to end	Day	26% 7% 26% 31% 9% 1	680
June	1st to 10th	Day	28% 5% 22% 35% 9% 1	630
	11th to 20th	Day	23% 6% 22% 36% 12% 1	630
	21st to end	Day	29% 5% 19% 34% 11% 2	630
July	1st to 10th	Day	23% 5% 21% 36% 14% 1	620
	11th to 20th	Day	25% 5% 15% 38% 17% 1	618
	21st to end	Day	21% 5% 18% 39% 15% 2	511
August	1st to 10th	Day	17% 6% 18% 39% 18% 2	446
	11th to 20th	Day	21% 7% 20% 30% 20% 3	439
	21st to end	Day	17% 4 23% 32% 21% 3	495
September	1st to 10th	Day	17% 3 21% 39% 18% 2	450
	11th to 20th	Day	22% 7% 23% 30% 14% 4	450
	21st to end	Day	20% 6% 24% 32% 14% 3	437
October	1st to 10th	Day	20% 5% 27% 31% 15% 2	360
	11th to 20th	Day	19% 12% 27% 26% 13% 3	360
	21st to end	Day	25% 12% 29% 26% 8% 1	396
November	1st to 10th	Day	21% 13% 28% 25% 12%	365
	11th to 20th	Day	24% 20% 27% 22% 6% 1	370
	21st to end	Day	24% 15% 33% 23% 4	370
December	1st to 10th	Day	32% 13% 32% 19% 4	370
	11th to 20th	Day	31% 23% 28% 16% 2	370
	21st to end	Day	24% 19% 34% 20% 4 1	407
January	1st to 10th	Night	25% 17% 33% 21% 4	850
	11th to 20th	Night	25% 15% 34% 22% 4	749
	21st to end	Night	21% 16% 37% 21% 5%	792
February	1st to 10th	Night	28% 16% 33% 22% 2	720
	11th to 20th	Night	23% 18% 37% 20% 2	703
	21st to end	Night	17% 13% 41% 23% 6%	592
March	1st to 10th	Night	25% 13% 38% 22% 3	720
	11th to 20th	Night	22% 11% 31% 28% 8%	720
	21st to end	Night	22% 12% 33% 26% 7% 1	792
April	1st to 10th	Night	34% 8% 28% 24% 6%	584
	11th to 20th	Night	28% 5% 34% 26% 6% 1	534
	21st to end	Night	28% 5% 26% 29% 11% 2	540
May	1st to 10th	Night	30% 4 26% 31% 8% 2	540
	11th to 20th	Night	27% 4 25% 31% 11% 2	532
	21st to end	Night	25% 4 23% 36% 11% 2	583
June	1st to 10th	Night	30% 5% 20% 32% 13% 1	540
	11th to 20th	Night	27% 4 20% 38% 11%	466
	21st to end	Night	30% 4 16% 32% 17% 1	360
July	1st to 10th	Night	23% 4 15% 42% 16% 1	392
	11th to 20th	Night	21% 5% 15% 43% 15% 1	522
	21st to end	Night	24% 6% 12% 41% 17% 1	590
August	1st to 10th	Night	17% 2 16% 40% 22% 3	538
	11th to 20th	Night	20% 3 18% 36% 21% 2	532
	21st to end	Night	18% 3 18% 36% 20% 4	594
September	1st to 10th	Night	17% 5% 19% 38% 19% 2	540
	11th to 20th	Night	22% 4 22% 31% 17% 4	656
	21st to end	Night	23% 6% 23% 30% 13% 4	720
October	1st to 10th	Night	24% 5% 26% 32% 13% 2	720
	11th to 20th	Night	20% 10% 29% 26% 13% 2	720
	21st to end	Night	27% 11% 29% 27% 6%	792
November	1st to 10th	Night	22% 11% 28% 29% 9% 1	789
	11th to 20th	Night	24% 16% 28% 24% 7%	850
	21st to end	Night	24% 17% 31% 20% 7% 1	850
December	1st to 10th	Night	29% 13% 33% 20% 5% 1	850
	11th to 20th	Night	27% 21% 32% 16% 3	850
	21st to end	Night	26% 16% 34% 19% 5%	935

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