Quadeville Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Quadeville Road clear sky chart from 2005-11-06 to 2026-01-02.

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% 12% 4 9% 5% 5% 4 3 5% 6% 31%	127712
	Night	15% 13% 4 10% 6% 5% 4 3 5% 6% 30%	123627
Transparency	Day	53% 5% 10% 20% 11% 1	131229
	Night	54% 5% 11% 19% 10% 1	128197
Seeing	Day	24% 18% 31% 17% 7% 2	15789
	Night	22% 16% 31% 22% 8% 1	25037

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% 16% 5% 15% 11% 8% 5% 3 5% 4 16%	3605
	11th to 20th	Day	11% 16% 7% 18% 8% 6% 5% 3 5% 5% 16%	3570
	21st to end	Day	12% 18% 8% 17% 7% 5% 4 3 3 4 19%	4343
February	1st to 10th	Day	12% 16% 5% 15% 9% 5% 5% 4 5% 4 20%	1800
	11th to 20th	Day	11% 16% 7% 13% 7% 5% 4 3 5% 5% 25%	1753
	21st to end	Day	16% 17% 5% 9% 7% 5% 5% 4 4 5% 22%	1583
March	1st to 10th	Day	16% 16% 5% 12% 6% 4 4 3 4 7% 24%	4695
	11th to 20th	Day	10% 14% 5% 11% 7% 5% 5% 4 6% 7% 27%	4980
	21st to end	Day	16% 14% 4 9% 4 3 3 2 4 4 37%	5620
April	1st to 10th	Day	20% 15% 3 8% 5% 4 4 2 4 5% 29%	2400
	11th to 20th	Day	22% 12% 3 6% 4 4 3 3 3 4 36%	2374
	21st to end	Day	22% 12% 3 7% 4 3 4 3 4 5% 33%	2580
May	1st to 10th	Day	21% 9% 3 8% 5% 5% 4 3 4 6% 31%	6292
	11th to 20th	Day	15% 10% 4 8% 5% 5% 4 4 5% 7% 34%	6318
	21st to end	Day	19% 9% 3 8% 5% 5% 4 3 5% 6% 33%	6949
June	1st to 10th	Day	21% 9% 3 7% 5% 4 5% 4 5% 6% 31%	2800
	11th to 20th	Day	15% 6% 3 6% 5% 5% 5% 4 6% 8% 37%	2800
	21st to end	Day	17% 8% 2 7% 5% 4 5% 4 6% 8% 33%	2800
July	1st to 10th	Day	14% 7% 3 7% 5% 5% 6% 4 7% 8% 34%	6360
	11th to 20th	Day	11% 6% 3 6% 4 4 5% 4 6% 8% 43%	6360
	21st to end	Day	9% 5% 2 6% 4 4 4 4 6% 9% 46%	6926
August	1st to 10th	Day	15% 8% 3 8% 6% 4 5% 4 6% 7% 33%	4314
	11th to 20th	Day	18% 7% 2 6% 5% 4 5% 4 7% 8% 34%	4174
	21st to end	Day	11% 6% 3 6% 4 5% 5% 5% 7% 10% 39%	4379
September	1st to 10th	Day	15% 7% 2 6% 4 5% 4 4 5% 7% 40%	2400
	11th to 20th	Day	12% 8% 2 6% 4 4 4 3 5% 7% 45%	2400
	21st to end	Day	18% 8% 2 7% 5% 4 4 4 5% 6% 36%	2100
October	1st to 10th	Day	20% 10% 3 6% 5% 4 3 4 5% 6% 35%	2000
	11th to 20th	Day	21% 14% 4 8% 5% 5% 4 3 4 6% 27%	2000
	21st to end	Day	25% 14% 4 9% 6% 5% 5% 3 4 5% 22%	2115
November	1st to 10th	Day	15% 14% 4 8% 5% 5% 5% 3 4 6% 33%	1768
	11th to 20th	Day	15% 16% 6% 11% 6% 4 5% 3 5% 5% 25%	1680
	21st to end	Day	20% 19% 6% 11% 6% 5% 4 3 4 5% 17%	1680
December	1st to 10th	Day	17% 25% 7% 12% 7% 5% 4 3 3 5% 11%	2680
	11th to 20th	Day	15% 20% 7% 14% 6% 4 3 2 3 4 22%	3066
	21st to end	Day	20% 19% 7% 14% 5% 4 4 2 3 4 18%	4048
January	1st to 10th	Night	12% 16% 9% 17% 9% 5% 4 2 4 4 17%	6364
	11th to 20th	Night	9% 14% 6% 17% 10% 7% 6% 4 5% 6% 16%	6315
	21st to end	Night	12% 17% 8% 15% 7% 7% 5% 3 4 4 18%	6610
February	1st to 10th	Night	11% 18% 6% 12% 8% 6% 5% 4 4 5% 21%	2600
	11th to 20th	Night	12% 14% 6% 11% 7% 6% 4 4 5% 5% 27%	2533
	21st to end	Night	12% 16% 5% 10% 6% 5% 4 4 5% 6% 27%	2045
March	1st to 10th	Night	18% 15% 4 11% 6% 4 4 3 3 4 28%	5144
	11th to 20th	Night	9% 13% 5% 11% 6% 5% 6% 4 7% 8% 26%	4979
	21st to end	Night	15% 13% 5% 9% 6% 4 4 3 5% 6% 31%	5298
April	1st to 10th	Night	19% 13% 4 9% 5% 4 3 3 4 5% 31%	2000
	11th to 20th	Night	17% 11% 4 6% 4 5% 4 2 4 5% 37%	1975
	21st to end	Night	19% 12% 3 7% 5% 5% 4 4 5% 6% 31%	1835
May	1st to 10th	Night	22% 9% 3 7% 4 4 5% 4 5% 6% 30%	3645
	11th to 20th	Night	15% 7% 2 6% 5% 4 3 3 5% 7% 43%	3575
	21st to end	Night	18% 9% 2 7% 5% 4 4 4 5% 7% 34%	3926
June	1st to 10th	Night	15% 9% 3 7% 5% 4 5% 4 6% 8% 35%	1600
	11th to 20th	Night	14% 6% 3 6% 4 4 5% 4 4 7% 43%	1600
	21st to end	Night	19% 6% 2 7% 4 4 5% 4 6% 7% 36%	1600
July	1st to 10th	Night	12% 7% 2 7% 5% 5% 5% 5% 6% 8% 37%	3600
	11th to 20th	Night	12% 6% 2 6% 4 4 4 4 5% 8% 47%	3600
	21st to end	Night	8% 6% 2 5% 4 4 5% 4 6% 8% 49%	3926
August	1st to 10th	Night	11% 6% 2 6% 4 4 4 4 6% 8% 43%	2831
	11th to 20th	Night	14% 7% 2 5% 4 4 4 3 5% 7% 44%	2875
	21st to end	Night	13% 5% 2 5% 4 5% 4 4 7% 9% 44%	3485
September	1st to 10th	Night	12% 6% 2 5% 4 4 4 4 5% 7% 47%	2000
	11th to 20th	Night	13% 5% 2 5% 4 3 4 3 4 7% 51%	2000
	21st to end	Night	17% 8% 3 6% 4 4 4 3 5% 5% 41%	2297
October	1st to 10th	Night	18% 9% 3 5% 4 4 4 3 4 7% 39%	2400
	11th to 20th	Night	19% 13% 3 8% 6% 5% 5% 3 4 5% 30%	2400
	21st to end	Night	20% 15% 4 8% 5% 5% 4 4 4 6% 26%	2725
November	1st to 10th	Night	15% 15% 4 8% 6% 4 4 3 5% 5% 31%	2746
	11th to 20th	Night	16% 14% 6% 10% 5% 5% 5% 3 4 5% 27%	2940
	21st to end	Night	18% 18% 5% 12% 6% 5% 3 3 5% 5% 19%	2940
December	1st to 10th	Night	17% 20% 7% 14% 7% 5% 4 3 5% 5% 14%	4720
	11th to 20th	Night	18% 18% 7% 13% 5% 4 3 3 3 4 22%	5348
	21st to end	Night	22% 20% 5% 13% 6% 4 3 2 3 4 17%	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	71% 4 8% 9% 7%	3606
	11th to 20th	Day	70% 5% 8% 9% 8% 1	3600
	21st to end	Day	70% 3 6% 11% 8% 1	4343
February	1st to 10th	Day	66% 4 8% 15% 6% 1	1800
	11th to 20th	Day	61% 4 10% 15% 9% 1	1762
	21st to end	Day	63% 5% 9% 12% 10% 2	1583
March	1st to 10th	Day	61% 3 9% 10% 14% 2	4698
	11th to 20th	Day	56% 4 14% 15% 9% 2	4980
	21st to end	Day	51% 3 6% 20% 17% 3	5620
April	1st to 10th	Day	57% 4 6% 18% 12% 3	2400
	11th to 20th	Day	53% 4 6% 21% 15% 1	2374
	21st to end	Day	54% 4 7% 17% 15% 3	2580
May	1st to 10th	Day	54% 5% 8% 19% 10% 4	6303
	11th to 20th	Day	49% 6% 10% 19% 15% 1	6322
	21st to end	Day	51% 4 11% 19% 12% 2	6949
June	1st to 10th	Day	53% 5% 10% 19% 12% 1	2800
	11th to 20th	Day	44% 6% 11% 24% 14% 2	2800
	21st to end	Day	47% 7% 11% 21% 12% 1	2800
July	1st to 10th	Day	45% 5% 13% 26% 10%	6290
	11th to 20th	Day	38% 6% 12% 29% 15%	6285
	21st to end	Day	34% 6% 13% 36% 11%	6728
August	1st to 10th	Day	48% 5% 14% 22% 10%	4300
	11th to 20th	Day	46% 6% 15% 26% 7% 1	4213
	21st to end	Day	38% 6% 14% 31% 10% 1	4379
September	1st to 10th	Day	42% 6% 13% 28% 11%	2400
	11th to 20th	Day	38% 5% 12% 31% 15%	2400
	21st to end	Day	48% 5% 13% 23% 11%	2100
October	1st to 10th	Day	50% 4 9% 28% 8%	3260
	11th to 20th	Day	50% 5% 12% 22% 11% 1	3240
	21st to end	Day	59% 4 14% 17% 6% 1	3392
November	1st to 10th	Day	52% 6% 12% 22% 7% 1	1768
	11th to 20th	Day	60% 5% 12% 13% 9% 1	1680
	21st to end	Day	69% 5% 9% 10% 6% 1	1680
December	1st to 10th	Day	77% 4 9% 7% 2	2680
	11th to 20th	Day	68% 4 8% 12% 8%	3066
	21st to end	Day	72% 2 7% 14% 5%	4048
January	1st to 10th	Night	71% 3 10% 11% 5%	6364
	11th to 20th	Night	68% 4 10% 11% 6%	6360
	21st to end	Night	70% 3 7% 8% 11% 1	6610
February	1st to 10th	Night	64% 4 11% 14% 7% 1	2600
	11th to 20th	Night	59% 5% 10% 18% 7% 1	2535
	21st to end	Night	57% 4 10% 18% 10% 1	2045
March	1st to 10th	Night	61% 3 8% 15% 9% 4	5154
	11th to 20th	Night	54% 5% 16% 16% 8% 2	4980
	21st to end	Night	53% 5% 7% 20% 13% 2	5298
April	1st to 10th	Night	56% 3 8% 19% 12% 2	2000
	11th to 20th	Night	50% 3 7% 24% 14% 1	1975
	21st to end	Night	53% 5% 8% 17% 16% 2	1835
May	1st to 10th	Night	52% 6% 9% 20% 9% 4	3651
	11th to 20th	Night	40% 7% 14% 23% 14% 2	3576
	21st to end	Night	48% 6% 12% 20% 13% 1	3927
June	1st to 10th	Night	45% 6% 13% 24% 11% 1	1600
	11th to 20th	Night	39% 7% 10% 27% 16% 1	1600
	21st to end	Night	44% 7% 14% 21% 13% 1	1600
July	1st to 10th	Night	44% 7% 15% 20% 13% 1	3560
	11th to 20th	Night	36% 5% 12% 33% 13%	3552
	21st to end	Night	33% 6% 12% 36% 13%	3809
August	1st to 10th	Night	38% 6% 15% 27% 12% 2	2821
	11th to 20th	Night	39% 5% 16% 30% 9% 1	2902
	21st to end	Night	36% 6% 15% 31% 10% 2	3485
September	1st to 10th	Night	36% 6% 15% 30% 13% 1	2000
	11th to 20th	Night	34% 5% 13% 36% 12% 1	2000
	21st to end	Night	44% 5% 11% 28% 11%	2297
October	1st to 10th	Night	40% 4 12% 29% 15%	3920
	11th to 20th	Night	48% 5% 15% 21% 11% 1	3899
	21st to end	Night	52% 5% 17% 19% 7%	4398
November	1st to 10th	Night	53% 5% 13% 20% 8%	2746
	11th to 20th	Night	59% 5% 11% 17% 7% 1	2940
	21st to end	Night	66% 5% 11% 14% 4	2940
December	1st to 10th	Night	70% 5% 12% 10% 2	4720
	11th to 20th	Night	67% 3 7% 12% 10% 1	5348
	21st to end	Night	72% 3 6% 11% 8%	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% 24% 39% 10% 4	202
	11th to 20th	Day	26% 21% 39% 11% 4 1	200
	21st to end	Day	23% 26% 34% 14% 2	302
February	1st to 10th	Day	31% 29% 30% 7% 3	300
	11th to 20th	Day	27% 32% 37% 4	300
	21st to end	Day	34% 22% 35% 9% 1	347
March	1st to 10th	Day	26% 26% 32% 13% 2	500
	11th to 20th	Day	30% 20% 33% 14% 3	500
	21st to end	Day	33% 23% 29% 11% 4 1	550
April	1st to 10th	Day	31% 25% 27% 12% 4	500
	11th to 20th	Day	36% 20% 23% 11% 9% 1	492
	21st to end	Day	32% 20% 32% 10% 5% 1	500
May	1st to 10th	Day	27% 19% 30% 15% 6% 3	503
	11th to 20th	Day	21% 17% 34% 20% 7% 2	527
	21st to end	Day	23% 17% 32% 17% 9% 2	573
June	1st to 10th	Day	25% 15% 36% 17% 6%	530
	11th to 20th	Day	16% 19% 31% 22% 9% 2	530
	21st to end	Day	21% 15% 36% 18% 9% 2	530
July	1st to 10th	Day	12% 10% 35% 33% 8% 2	525
	11th to 20th	Day	13% 14% 35% 25% 11% 2	524
	21st to end	Day	14% 11% 39% 24% 10% 3	576
August	1st to 10th	Day	15% 8% 32% 30% 11% 4	526
	11th to 20th	Day	15% 9% 29% 27% 14% 5%	519
	21st to end	Day	15% 13% 32% 25% 11% 4	583
September	1st to 10th	Day	18% 14% 29% 20% 14% 5%	530
	11th to 20th	Day	12% 11% 23% 27% 16% 11%	530
	21st to end	Day	21% 15% 28% 21% 11% 5%	530
October	1st to 10th	Day	25% 17% 27% 17% 11% 3	530
	11th to 20th	Day	28% 22% 31% 14% 5% 1	530
	21st to end	Day	30% 20% 30% 16% 4	536
November	1st to 10th	Day	27% 21% 31% 15% 5%	342
	11th to 20th	Day	29% 22% 34% 9% 6% 1	220
	21st to end	Day	33% 29% 28% 7% 2	220
December	1st to 10th	Day	29% 19% 38% 13% 1	220
	11th to 20th	Day	31% 32% 25% 9% 1 1	220
	21st to end	Day	32% 25% 27% 12% 3 1	242
January	1st to 10th	Night	24% 22% 36% 14% 3	805
	11th to 20th	Night	25% 20% 31% 18% 5% 1	800
	21st to end	Night	17% 19% 36% 21% 6%	880
February	1st to 10th	Night	20% 23% 38% 17% 2	800
	11th to 20th	Night	21% 23% 39% 14% 3	783
	21st to end	Night	22% 23% 33% 19% 3	660
March	1st to 10th	Night	25% 22% 33% 17% 3	800
	11th to 20th	Night	24% 20% 33% 18% 4 1	800
	21st to end	Night	22% 20% 33% 19% 6%	880
April	1st to 10th	Night	29% 17% 31% 19% 4	800
	11th to 20th	Night	25% 21% 29% 18% 8%	791
	21st to end	Night	25% 17% 26% 23% 9%	635
May	1st to 10th	Night	24% 10% 28% 28% 9% 1	425
	11th to 20th	Night	21% 11% 33% 28% 7%	394
	21st to end	Night	16% 11% 33% 30% 10%	433
June	1st to 10th	Night	17% 10% 38% 29% 7% 1	400
	11th to 20th	Night	18% 10% 33% 30% 9% 1	400
	21st to end	Night	19% 12% 28% 30% 11% 1	400
July	1st to 10th	Night	10% 9% 35% 34% 11% 1	390
	11th to 20th	Night	12% 8% 28% 39% 13%	388
	21st to end	Night	10% 6% 33% 39% 11% 1	438
August	1st to 10th	Night	10% 4 27% 39% 19% 1	539
	11th to 20th	Night	10% 6% 25% 37% 19% 3	594
	21st to end	Night	15% 8% 29% 31% 15% 2	818
September	1st to 10th	Night	14% 9% 31% 28% 16% 2	800
	11th to 20th	Night	17% 6% 24% 29% 20% 4	800
	21st to end	Night	21% 11% 24% 25% 16% 3	800
October	1st to 10th	Night	23% 13% 29% 22% 12% 2	800
	11th to 20th	Night	27% 16% 31% 18% 8% 1	800
	21st to end	Night	28% 16% 28% 21% 5%	880
November	1st to 10th	Night	27% 17% 28% 21% 6% 1	820
	11th to 20th	Night	25% 21% 30% 15% 8% 1	840
	21st to end	Night	31% 19% 26% 20% 3	840
December	1st to 10th	Night	28% 20% 33% 15% 4	840
	11th to 20th	Night	26% 24% 30% 16% 3 1	840
	21st to end	Night	33% 19% 30% 15% 3	924

Page generated at 2025-12-30 01:14:06. Version ac07

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