Quinte West
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Quinte West clear sky chart from 2005-11-06 to 2026-05-02.

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	15% 9% 3 8% 5% 4 4 4 5% 7% 35%	132086
	Night	16% 10% 3 8% 5% 5% 4 4 5% 7% 34%	130390
Transparency	Day	47% 6% 13% 21% 11% 1	135640
	Night	49% 6% 12% 20% 12% 1	134923
Seeing	Day	21% 15% 31% 21% 9% 3	16290
	Night	20% 12% 31% 26% 10% 1	25666

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	16% 13% 4 9% 5% 4 5% 4 6% 7% 28%	4661
	11th to 20th	Day	11% 20% 8% 15% 8% 5% 5% 3 5% 4 17%	4687
	21st to end	Day	12% 16% 7% 12% 6% 6% 5% 4 5% 6% 22%	5780
February	1st to 10th	Day	13% 15% 5% 11% 7% 4 5% 4 6% 5% 26%	1890
	11th to 20th	Day	13% 13% 4 11% 8% 5% 5% 3 5% 5% 27%	1843
	21st to end	Day	19% 13% 4 11% 6% 4 4 4 4 5% 26%	1667
March	1st to 10th	Day	20% 11% 3 8% 4 4 4 3 4 5% 33%	4855
	11th to 20th	Day	11% 12% 3 9% 6% 6% 5% 3 6% 7% 32%	5090
	21st to end	Day	19% 10% 3 7% 4 4 3 3 3 5% 39%	5714
April	1st to 10th	Day	18% 11% 3 8% 5% 4 4 3 4 6% 32%	2520
	11th to 20th	Day	20% 9% 3 6% 4 4 4 3 4 5% 38%	2494
	21st to end	Day	20% 9% 3 8% 5% 5% 4 3 5% 6% 34%	2693
May	1st to 10th	Day	21% 9% 3 8% 5% 4 4 3 5% 6% 31%	6176
	11th to 20th	Day	16% 10% 4 8% 4 4 4 3 5% 7% 35%	6318
	21st to end	Day	18% 7% 2 7% 5% 4 4 4 6% 8% 37%	6949
June	1st to 10th	Day	17% 7% 2 6% 5% 5% 5% 4 7% 8% 34%	2800
	11th to 20th	Day	12% 6% 3 5% 5% 4 5% 4 7% 9% 40%	2800
	21st to end	Day	14% 7% 3 6% 4 4 4 4 6% 9% 39%	2800
July	1st to 10th	Day	9% 6% 3 6% 4 5% 5% 4 6% 10% 43%	6360
	11th to 20th	Day	9% 5% 2 5% 4 5% 4 4 7% 9% 47%	6360
	21st to end	Day	7% 4 2 6% 4 5% 5% 5% 7% 9% 47%	6867
August	1st to 10th	Day	15% 7% 2 7% 4 4 4 4 6% 8% 40%	4234
	11th to 20th	Day	13% 6% 2 6% 4 3 5% 4 7% 10% 39%	4174
	21st to end	Day	11% 5% 2 5% 4 4 6% 5% 6% 8% 44%	4355
September	1st to 10th	Day	12% 6% 2 4 4 4 4 4 5% 8% 46%	2400
	11th to 20th	Day	10% 5% 2 6% 4 3 3 3 6% 7% 52%	2400
	21st to end	Day	15% 7% 2 7% 5% 4 4 3 5% 6% 41%	2090
October	1st to 10th	Day	16% 8% 3 7% 4 4 5% 3 5% 7% 38%	2000
	11th to 20th	Day	18% 7% 3 8% 4 6% 4 5% 5% 7% 33%	2000
	21st to end	Day	23% 10% 3 7% 6% 4 5% 3 5% 6% 28%	2160
November	1st to 10th	Day	15% 8% 3 7% 6% 5% 4 3 5% 8% 36%	1795
	11th to 20th	Day	15% 11% 3 8% 5% 4 5% 4 6% 7% 33%	1680
	21st to end	Day	19% 13% 4 8% 6% 5% 4 4 5% 6% 26%	1680
December	1st to 10th	Day	19% 14% 5% 11% 6% 5% 5% 4 5% 6% 21%	2680
	11th to 20th	Day	16% 15% 6% 10% 5% 5% 4 3 4 4 27%	3066
	21st to end	Day	25% 13% 4 9% 5% 4 4 3 4 6% 23%	4048
January	1st to 10th	Night	15% 13% 7% 12% 6% 5% 5% 4 5% 5% 24%	8234
	11th to 20th	Night	13% 15% 6% 14% 9% 6% 5% 4 5% 5% 18%	8197
	21st to end	Night	13% 13% 5% 10% 6% 6% 6% 4 5% 6% 27%	8401
February	1st to 10th	Night	14% 15% 4 10% 6% 5% 5% 4 5% 5% 27%	2730
	11th to 20th	Night	14% 14% 4 10% 5% 5% 5% 4 6% 6% 28%	2663
	21st to end	Night	15% 11% 4 9% 5% 4 5% 4 5% 7% 31%	2139
March	1st to 10th	Night	18% 10% 3 9% 6% 5% 5% 3 5% 5% 31%	5202
	11th to 20th	Night	12% 10% 3 7% 5% 5% 5% 5% 6% 7% 35%	5089
	21st to end	Night	20% 9% 3 6% 3 3 3 2 5% 6% 40%	5459
April	1st to 10th	Night	18% 10% 3 7% 5% 4 5% 3 6% 6% 33%	2100
	11th to 20th	Night	18% 9% 3 7% 4 5% 3 3 5% 6% 37%	2075
	21st to end	Night	18% 6% 3 7% 5% 4 3 5% 6% 7% 36%	1945
May	1st to 10th	Night	27% 8% 3 7% 4 4 4 4 5% 5% 29%	3786
	11th to 20th	Night	13% 7% 3 8% 5% 4 4 3 5% 7% 41%	3575
	21st to end	Night	18% 7% 2 6% 5% 4 5% 4 6% 7% 38%	3926
June	1st to 10th	Night	14% 5% 3 8% 5% 4 5% 5% 7% 7% 38%	1600
	11th to 20th	Night	10% 5% 2 7% 5% 4 5% 5% 6% 9% 43%	1600
	21st to end	Night	12% 6% 3 8% 5% 5% 4 4 5% 7% 42%	1600
July	1st to 10th	Night	8% 6% 2 6% 5% 5% 5% 4 7% 10% 42%	3600
	11th to 20th	Night	9% 5% 2 5% 4 4 4 4 5% 7% 49%	3600
	21st to end	Night	9% 5% 2 5% 4 3 3 3 6% 9% 51%	3969
August	1st to 10th	Night	9% 6% 2 6% 4 4 4 4 5% 8% 47%	2915
	11th to 20th	Night	12% 6% 2 6% 3 4 3 4 5% 7% 47%	2875
	21st to end	Night	8% 4 2 5% 4 4 5% 5% 7% 9% 48%	3508
September	1st to 10th	Night	10% 5% 2 6% 4 3 4 3 7% 8% 47%	2000
	11th to 20th	Night	11% 4 1 4 4 3 4 3 6% 7% 54%	2000
	21st to end	Night	17% 6% 2 6% 4 4 4 3 4 6% 43%	2304
October	1st to 10th	Night	16% 6% 2 7% 4 5% 4 4 5% 7% 41%	2400
	11th to 20th	Night	20% 8% 3 8% 5% 4 5% 3 5% 6% 34%	2400
	21st to end	Night	21% 9% 3 7% 5% 4 4 4 5% 7% 32%	2680
November	1st to 10th	Night	18% 8% 2 6% 4 4 4 3 5% 7% 39%	2720
	11th to 20th	Night	16% 10% 3 7% 5% 5% 5% 4 6% 7% 33%	2940
	21st to end	Night	21% 11% 3 7% 5% 5% 5% 5% 6% 6% 27%	2940
December	1st to 10th	Night	19% 14% 3 7% 5% 5% 5% 4 6% 8% 23%	4720
	11th to 20th	Night	18% 14% 4 9% 5% 4 4 3 5% 6% 27%	5348
	21st to end	Night	26% 14% 4 9% 5% 4 4 3 5% 5% 21%	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	54% 6% 13% 19% 8% 1	4662
	11th to 20th	Day	70% 5% 8% 9% 7% 1	4717
	21st to end	Day	64% 4 10% 11% 10% 1	5780
February	1st to 10th	Day	59% 7% 11% 16% 6% 1	1890
	11th to 20th	Day	58% 5% 10% 15% 10% 1	1852
	21st to end	Day	60% 6% 11% 14% 9% 1	1667
March	1st to 10th	Day	54% 4 12% 14% 15% 1	4858
	11th to 20th	Day	50% 5% 20% 13% 10% 2	5090
	21st to end	Day	48% 4 7% 21% 17% 2	5714
April	1st to 10th	Day	53% 5% 10% 19% 11% 2	2520
	11th to 20th	Day	49% 4 9% 21% 15% 1	2494
	21st to end	Day	51% 5% 10% 18% 12% 2	2693
May	1st to 10th	Day	53% 6% 10% 18% 11% 3	6185
	11th to 20th	Day	48% 7% 11% 17% 16% 1	6322
	21st to end	Day	45% 7% 13% 22% 11% 2	6949
June	1st to 10th	Day	45% 8% 13% 19% 14% 1	2800
	11th to 20th	Day	38% 8% 14% 25% 14% 2	2800
	21st to end	Day	41% 8% 14% 23% 13% 1	2800
July	1st to 10th	Day	37% 6% 14% 29% 14% 1	6290
	11th to 20th	Day	32% 7% 15% 30% 16%	6285
	21st to end	Day	32% 7% 14% 35% 12%	6670
August	1st to 10th	Day	42% 7% 15% 23% 12% 1	4221
	11th to 20th	Day	40% 7% 15% 28% 9%	4213
	21st to end	Day	35% 7% 13% 34% 10% 1	4355
September	1st to 10th	Day	35% 8% 15% 29% 12% 1	2400
	11th to 20th	Day	31% 6% 15% 33% 15% 1	2400
	21st to end	Day	42% 8% 13% 27% 9%	2090
October	1st to 10th	Day	38% 6% 13% 30% 13% 1	3260
	11th to 20th	Day	41% 7% 17% 23% 12% 1	3240
	21st to end	Day	49% 6% 14% 21% 10%	3474
November	1st to 10th	Day	47% 6% 16% 20% 10% 1	1795
	11th to 20th	Day	49% 8% 15% 17% 11% 1	1680
	21st to end	Day	58% 9% 13% 13% 7%	1680
December	1st to 10th	Day	64% 5% 16% 11% 4	2680
	11th to 20th	Day	61% 7% 9% 14% 9%	3066
	21st to end	Day	63% 6% 9% 15% 7%	4048
January	1st to 10th	Night	61% 6% 11% 15% 7%	8234
	11th to 20th	Night	65% 7% 10% 10% 7% 1	8242
	21st to end	Night	56% 5% 10% 14% 14% 1	8401
February	1st to 10th	Night	58% 5% 12% 18% 6% 1	2730
	11th to 20th	Night	56% 6% 11% 19% 8%	2665
	21st to end	Night	51% 7% 12% 21% 9% 1	2139
March	1st to 10th	Night	54% 5% 8% 17% 12% 4	5212
	11th to 20th	Night	45% 7% 17% 19% 10% 2	5090
	21st to end	Night	45% 4 9% 22% 17% 2	5459
April	1st to 10th	Night	50% 5% 10% 20% 13% 2	2100
	11th to 20th	Night	47% 6% 10% 19% 17% 1	2075
	21st to end	Night	46% 7% 11% 18% 15% 3	1945
May	1st to 10th	Night	55% 7% 9% 14% 11% 4	3793
	11th to 20th	Night	42% 6% 15% 22% 15% 2	3576
	21st to end	Night	44% 7% 13% 19% 15% 2	3927
June	1st to 10th	Night	42% 7% 12% 23% 15% 2	1600
	11th to 20th	Night	36% 7% 14% 22% 19% 3	1600
	21st to end	Night	41% 7% 14% 23% 14% 2	1600
July	1st to 10th	Night	36% 6% 16% 22% 19% 1	3560
	11th to 20th	Night	33% 6% 12% 33% 16% 1	3552
	21st to end	Night	30% 7% 13% 34% 15% 1	3852
August	1st to 10th	Night	35% 6% 13% 30% 15% 2	2904
	11th to 20th	Night	35% 7% 16% 28% 13% 1	2902
	21st to end	Night	30% 8% 13% 37% 12% 1	3508
September	1st to 10th	Night	34% 7% 16% 29% 14% 1	2000
	11th to 20th	Night	29% 8% 13% 33% 17% 1	2000
	21st to end	Night	42% 6% 11% 26% 13% 1	2304
October	1st to 10th	Night	35% 5% 10% 28% 21% 1	3920
	11th to 20th	Night	42% 5% 15% 29% 9%	3899
	21st to end	Night	44% 5% 14% 26% 10%	4316
November	1st to 10th	Night	44% 7% 13% 23% 12% 1	2720
	11th to 20th	Night	49% 7% 13% 19% 10% 2	2940
	21st to end	Night	54% 9% 15% 16% 5% 1	2940
December	1st to 10th	Night	58% 7% 14% 17% 4	4720
	11th to 20th	Night	58% 7% 12% 13% 10% 1	5348
	21st to end	Night	65% 6% 10% 11% 9%	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	24% 24% 32% 14% 6%	220
	11th to 20th	Day	29% 23% 30% 14% 3 1	226
	21st to end	Day	26% 24% 29% 15% 4 1	363
February	1st to 10th	Day	28% 26% 29% 13% 3	330
	11th to 20th	Day	26% 26% 38% 8% 1	330
	21st to end	Day	32% 22% 34% 11% 1	383
March	1st to 10th	Day	24% 20% 37% 16% 4	540
	11th to 20th	Day	27% 22% 30% 17% 3	540
	21st to end	Day	31% 19% 30% 13% 6% 1	594
April	1st to 10th	Day	28% 22% 32% 11% 6% 1	540
	11th to 20th	Day	30% 22% 24% 15% 7% 3	532
	21st to end	Day	26% 19% 31% 16% 5% 2	540
May	1st to 10th	Day	24% 14% 33% 18% 7% 4	507
	11th to 20th	Day	18% 12% 35% 23% 10% 3	527
	21st to end	Day	16% 12% 31% 25% 12% 4	573
June	1st to 10th	Day	17% 14% 34% 24% 10% 2	530
	11th to 20th	Day	12% 13% 34% 26% 13% 3	530
	21st to end	Day	18% 11% 32% 25% 11% 2	530
July	1st to 10th	Day	10% 9% 30% 31% 17% 4	525
	11th to 20th	Day	14% 8% 29% 27% 17% 5%	524
	21st to end	Day	9% 8% 34% 32% 12% 4	576
August	1st to 10th	Day	12% 6% 29% 30% 16% 7%	526
	11th to 20th	Day	13% 5% 25% 30% 19% 7%	519
	21st to end	Day	11% 9% 31% 27% 14% 8%	583
September	1st to 10th	Day	13% 9% 28% 28% 13% 8%	530
	11th to 20th	Day	9% 8% 25% 25% 21% 13%	530
	21st to end	Day	16% 12% 28% 25% 14% 5%	530
October	1st to 10th	Day	19% 15% 25% 19% 15% 6%	530
	11th to 20th	Day	22% 18% 33% 18% 7% 2	530
	21st to end	Day	28% 18% 28% 22% 4	561
November	1st to 10th	Day	26% 17% 27% 21% 8% 1	369
	11th to 20th	Day	23% 21% 36% 15% 4	220
	21st to end	Day	26% 22% 34% 14% 4 1	220
December	1st to 10th	Day	29% 16% 35% 15% 5%	220
	11th to 20th	Day	30% 24% 32% 12% 2	220
	21st to end	Day	36% 19% 31% 12% 2	242
January	1st to 10th	Night	26% 19% 33% 19% 4	840
	11th to 20th	Night	27% 18% 31% 19% 5%	840
	21st to end	Night	22% 15% 35% 22% 5%	924
February	1st to 10th	Night	22% 18% 39% 20% 2	840
	11th to 20th	Night	22% 19% 36% 19% 4	823
	21st to end	Night	24% 18% 34% 20% 3	692
March	1st to 10th	Night	22% 16% 35% 23% 3	840
	11th to 20th	Night	23% 18% 33% 22% 3 1	840
	21st to end	Night	22% 15% 34% 22% 6% 1	924
April	1st to 10th	Night	23% 14% 37% 23% 3	840
	11th to 20th	Night	22% 16% 31% 22% 8% 1	831
	21st to end	Night	21% 12% 31% 26% 10% 1	685
May	1st to 10th	Night	23% 7% 28% 28% 12% 1	483
	11th to 20th	Night	14% 8% 34% 35% 10%	394
	21st to end	Night	12% 6% 33% 34% 14% 1	433
June	1st to 10th	Night	15% 4 35% 33% 13% 1	400
	11th to 20th	Night	12% 7% 29% 36% 16% 1	400
	21st to end	Night	14% 6% 29% 37% 14% 1	400
July	1st to 10th	Night	6% 6% 27% 43% 18% 1	390
	11th to 20th	Night	10% 3 25% 38% 22% 1	388
	21st to end	Night	11% 2 27% 43% 17% 1	456
August	1st to 10th	Night	11% 3 18% 40% 26% 3	597
	11th to 20th	Night	9% 5% 19% 37% 26% 4	594
	21st to end	Night	9% 4 27% 36% 21% 2	828
September	1st to 10th	Night	12% 5% 28% 33% 20% 3	800
	11th to 20th	Night	13% 4 19% 31% 27% 5%	800
	21st to end	Night	19% 8% 21% 31% 19% 4	800
October	1st to 10th	Night	19% 9% 29% 25% 17% 3	800
	11th to 20th	Night	23% 12% 31% 25% 8% 1	800
	21st to end	Night	25% 13% 32% 24% 5%	880
November	1st to 10th	Night	22% 15% 26% 28% 8% 1	820
	11th to 20th	Night	23% 16% 34% 21% 5% 1	840
	21st to end	Night	28% 16% 30% 20% 6%	840
December	1st to 10th	Night	29% 17% 31% 20% 4	840
	11th to 20th	Night	25% 18% 35% 18% 3	840
	21st to end	Night	34% 14% 33% 17% 3	924

Page generated at 2026-04-29 02:21:42. Version ac07

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