Bonnechere Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bonnechere Provincial Park clear sky chart from 2005-11-06 to 2025-12-03.

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% 11% 4 9% 5% 5% 4 3 5% 6% 32%	127471
	Night	15% 12% 4 10% 5% 5% 4 3 5% 6% 30%	123212
Transparency	Day	52% 6% 11% 21% 10% 1	131001
	Night	54% 6% 11% 19% 9% 1	127769
Seeing	Day	23% 16% 31% 19% 9% 3	15689
	Night	22% 14% 30% 24% 9% 1	24882

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% 15% 7% 15% 10% 6% 4 3 4 4 19%	3597
	11th to 20th	Day	11% 15% 7% 17% 9% 5% 5% 3 4 6% 19%	3570
	21st to end	Day	12% 19% 8% 14% 6% 6% 4 3 3 4 21%	4345
February	1st to 10th	Day	10% 15% 6% 15% 9% 5% 5% 4 5% 4 21%	1800
	11th to 20th	Day	11% 17% 5% 12% 6% 6% 4 4 5% 5% 24%	1753
	21st to end	Day	17% 15% 4 9% 6% 6% 5% 4 5% 5% 23%	1566
March	1st to 10th	Day	18% 15% 5% 11% 6% 4 4 3 5% 5% 25%	4706
	11th to 20th	Day	11% 13% 5% 10% 6% 5% 5% 4 6% 7% 28%	4980
	21st to end	Day	16% 12% 4 9% 5% 4 3 3 3 5% 37%	5598
April	1st to 10th	Day	20% 14% 3 7% 5% 5% 4 4 4 6% 29%	2400
	11th to 20th	Day	22% 10% 3 6% 5% 4 3 3 4 5% 35%	2379
	21st to end	Day	21% 10% 3 7% 5% 4 4 3 5% 5% 33%	2600
May	1st to 10th	Day	20% 9% 3 7% 5% 5% 4 3 5% 6% 34%	6290
	11th to 20th	Day	15% 9% 3 8% 4 4 4 4 5% 7% 37%	6318
	21st to end	Day	20% 9% 2 7% 5% 5% 4 3 5% 6% 35%	6949
June	1st to 10th	Day	19% 9% 3 7% 5% 4 5% 4 5% 7% 31%	2800
	11th to 20th	Day	14% 6% 2 7% 5% 4 4 5% 6% 8% 39%	2800
	21st to end	Day	16% 7% 3 6% 5% 5% 5% 4 6% 8% 34%	2800
July	1st to 10th	Day	15% 6% 2 7% 5% 5% 5% 4 7% 9% 35%	6360
	11th to 20th	Day	10% 5% 2 6% 5% 5% 4 4 6% 7% 46%	6360
	21st to end	Day	9% 4 1 6% 4 4 5% 4 6% 9% 48%	6926
August	1st to 10th	Day	14% 6% 2 9% 6% 6% 5% 4 6% 7% 34%	4312
	11th to 20th	Day	16% 6% 2 6% 5% 5% 4 4 6% 8% 37%	4174
	21st to end	Day	10% 5% 2 6% 5% 6% 6% 4 6% 10% 41%	4411
September	1st to 10th	Day	15% 6% 2 6% 4 4 5% 3 6% 7% 41%	2400
	11th to 20th	Day	13% 6% 3 6% 5% 3 4 4 5% 7% 46%	2400
	21st to end	Day	19% 7% 3 8% 5% 4 5% 3 4 7% 36%	2094
October	1st to 10th	Day	19% 8% 3 7% 4 5% 4 3 5% 5% 36%	2000
	11th to 20th	Day	21% 12% 4 9% 5% 5% 4 3 4 5% 27%	2000
	21st to end	Day	25% 13% 4 10% 5% 5% 4 3 4 5% 22%	2120
November	1st to 10th	Day	15% 13% 5% 8% 5% 4 4 2 5% 7% 32%	1741
	11th to 20th	Day	15% 16% 5% 9% 6% 4 5% 3 5% 6% 24%	1680
	21st to end	Day	21% 17% 7% 11% 7% 5% 4 3 4 5% 17%	1680
December	1st to 10th	Day	17% 23% 6% 13% 7% 6% 4 3 4 4 12%	2616
	11th to 20th	Day	16% 20% 6% 12% 6% 4 5% 3 4 3 22%	2986
	21st to end	Day	20% 21% 5% 15% 4 4 3 2 3 4 18%	3960
January	1st to 10th	Night	13% 18% 10% 16% 8% 5% 4 3 4 4 16%	6349
	11th to 20th	Night	11% 13% 6% 17% 8% 7% 6% 4 5% 5% 19%	6315
	21st to end	Night	11% 18% 8% 14% 7% 8% 5% 3 4 4 18%	6610
February	1st to 10th	Night	11% 16% 5% 13% 9% 6% 4 4 5% 6% 21%	2600
	11th to 20th	Night	11% 14% 6% 12% 7% 5% 5% 3 5% 5% 26%	2533
	21st to end	Night	12% 15% 5% 11% 7% 5% 4 4 5% 6% 26%	2062
March	1st to 10th	Night	17% 15% 5% 10% 5% 4 4 3 3 5% 29%	5119
	11th to 20th	Night	11% 13% 5% 9% 6% 6% 5% 4 7% 8% 27%	4979
	21st to end	Night	15% 11% 4 10% 5% 4 4 3 6% 6% 31%	5333
April	1st to 10th	Night	18% 14% 4 8% 5% 4 4 3 5% 5% 30%	2000
	11th to 20th	Night	19% 11% 2 7% 4 4 4 2 4 6% 37%	1975
	21st to end	Night	20% 10% 3 8% 5% 4 5% 4 4 5% 32%	1810
May	1st to 10th	Night	22% 8% 2 6% 4 5% 4 4 6% 7% 31%	3650
	11th to 20th	Night	15% 6% 2 7% 4 5% 4 3 5% 7% 43%	3575
	21st to end	Night	18% 8% 2 7% 5% 5% 5% 4 6% 6% 35%	3926
June	1st to 10th	Night	17% 7% 3 8% 5% 5% 5% 4 5% 7% 36%	1600
	11th to 20th	Night	13% 6% 2 5% 4 4 6% 4 5% 7% 44%	1600
	21st to end	Night	16% 7% 3 6% 5% 5% 5% 4 5% 8% 36%	1600
July	1st to 10th	Night	13% 6% 2 7% 5% 5% 5% 5% 7% 7% 38%	3600
	11th to 20th	Night	13% 4 2 6% 4 4 4 3 6% 7% 47%	3600
	21st to end	Night	9% 4 2 6% 4 4 4 3 6% 8% 50%	3926
August	1st to 10th	Night	12% 5% 2 6% 4 5% 5% 4 6% 7% 44%	2834
	11th to 20th	Night	16% 5% 2 5% 4 3 4 4 5% 7% 45%	2875
	21st to end	Night	13% 4 2 6% 4 4 5% 4 6% 8% 45%	3454
September	1st to 10th	Night	12% 5% 1 5% 4 4 4 5% 5% 7% 48%	2000
	11th to 20th	Night	13% 5% 2 5% 3 3 3 3 5% 6% 51%	2000
	21st to end	Night	17% 8% 2 5% 4 4 4 3 5% 7% 41%	2303
October	1st to 10th	Night	20% 7% 2 6% 3 3 4 4 4 5% 42%	2400
	11th to 20th	Night	20% 11% 3 7% 5% 5% 4 3 5% 6% 30%	2400
	21st to end	Night	21% 13% 3 8% 5% 4 3 4 5% 6% 26%	2719
November	1st to 10th	Night	16% 13% 3 8% 6% 4 5% 4 6% 6% 31%	2772
	11th to 20th	Night	15% 15% 4 10% 7% 5% 4 3 5% 5% 27%	2940
	21st to end	Night	20% 17% 5% 10% 7% 4 5% 3 5% 5% 20%	2940
December	1st to 10th	Night	17% 20% 6% 12% 6% 5% 5% 4 5% 5% 14%	4609
	11th to 20th	Night	18% 17% 6% 12% 6% 5% 4 3 3 5% 23%	5208
	21st to end	Night	23% 19% 5% 14% 6% 4 3 3 3 4 16%	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	69% 6% 9% 10% 6%	3598
	11th to 20th	Day	67% 5% 9% 11% 8%	3600
	21st to end	Day	68% 4 6% 12% 8% 1	4345
February	1st to 10th	Day	65% 5% 9% 15% 5% 1	1800
	11th to 20th	Day	60% 6% 12% 13% 8% 1	1762
	21st to end	Day	62% 5% 8% 14% 10% 1	1566
March	1st to 10th	Day	61% 4 8% 12% 13% 2	4709
	11th to 20th	Day	54% 6% 16% 15% 8% 2	4980
	21st to end	Day	51% 5% 7% 20% 16% 3	5598
April	1st to 10th	Day	56% 5% 7% 18% 11% 3	2400
	11th to 20th	Day	52% 4 8% 21% 14% 2	2379
	21st to end	Day	53% 4 8% 17% 15% 3	2600
May	1st to 10th	Day	50% 6% 8% 21% 10% 5%	6301
	11th to 20th	Day	46% 7% 10% 22% 14% 1	6322
	21st to end	Day	50% 6% 10% 20% 12% 2	6949
June	1st to 10th	Day	52% 7% 10% 19% 12% 1	2800
	11th to 20th	Day	41% 7% 12% 24% 14% 2	2800
	21st to end	Day	47% 7% 12% 21% 12% 1	2800
July	1st to 10th	Day	43% 7% 13% 27% 9% 1	6290
	11th to 20th	Day	35% 7% 12% 32% 13%	6285
	21st to end	Day	32% 6% 15% 35% 12%	6728
August	1st to 10th	Day	47% 7% 13% 24% 9%	4298
	11th to 20th	Day	43% 7% 15% 26% 8%	4213
	21st to end	Day	37% 8% 13% 32% 10% 1	4411
September	1st to 10th	Day	40% 7% 14% 27% 11%	2400
	11th to 20th	Day	38% 7% 11% 32% 13%	2400
	21st to end	Day	49% 6% 12% 23% 10%	2094
October	1st to 10th	Day	52% 5% 9% 26% 8%	3260
	11th to 20th	Day	51% 6% 12% 23% 8%	3240
	21st to end	Day	58% 7% 15% 15% 5% 1	3410
November	1st to 10th	Day	53% 5% 13% 21% 7%	1741
	11th to 20th	Day	60% 6% 12% 13% 7% 1	1680
	21st to end	Day	71% 5% 10% 9% 5% 1	1680
December	1st to 10th	Day	76% 5% 8% 8% 2	2616
	11th to 20th	Day	67% 5% 6% 13% 9%	2986
	21st to end	Day	72% 4 5% 14% 4	3960
January	1st to 10th	Night	72% 5% 8% 11% 4	6349
	11th to 20th	Night	65% 8% 9% 11% 6%	6360
	21st to end	Night	69% 5% 6% 9% 10% 1	6610
February	1st to 10th	Night	64% 6% 10% 14% 6% 1	2600
	11th to 20th	Night	60% 5% 10% 18% 6% 1	2535
	21st to end	Night	57% 6% 10% 18% 8% 1	2062
March	1st to 10th	Night	59% 5% 8% 14% 10% 4	5129
	11th to 20th	Night	53% 7% 16% 15% 8% 1	4980
	21st to end	Night	51% 6% 10% 19% 12% 2	5333
April	1st to 10th	Night	55% 6% 8% 18% 11% 2	2000
	11th to 20th	Night	49% 4 8% 24% 13% 2	1975
	21st to end	Night	54% 5% 7% 16% 15% 2	1810
May	1st to 10th	Night	50% 6% 10% 20% 10% 4	3656
	11th to 20th	Night	39% 9% 14% 21% 15% 3	3576
	21st to end	Night	47% 8% 12% 20% 12% 1	3927
June	1st to 10th	Night	46% 8% 11% 22% 12% 1	1600
	11th to 20th	Night	38% 7% 12% 26% 16% 1	1600
	21st to end	Night	44% 8% 13% 20% 14% 1	1600
July	1st to 10th	Night	42% 7% 16% 23% 12% 1	3560
	11th to 20th	Night	36% 6% 12% 33% 12%	3552
	21st to end	Night	31% 7% 11% 38% 13%	3809
August	1st to 10th	Night	38% 7% 14% 27% 13%	2824
	11th to 20th	Night	38% 7% 17% 29% 10%	2902
	21st to end	Night	36% 8% 15% 29% 11% 2	3454
September	1st to 10th	Night	36% 7% 13% 30% 13% 1	2000
	11th to 20th	Night	35% 6% 14% 34% 11%	2000
	21st to end	Night	43% 7% 12% 28% 10%	2303
October	1st to 10th	Night	39% 5% 13% 31% 12%	3920
	11th to 20th	Night	48% 6% 16% 21% 10%	3899
	21st to end	Night	53% 6% 17% 17% 7%	4379
November	1st to 10th	Night	54% 6% 14% 19% 7%	2772
	11th to 20th	Night	59% 7% 11% 16% 6% 1	2940
	21st to end	Night	66% 6% 11% 13% 3	2940
December	1st to 10th	Night	71% 6% 11% 9% 2	4609
	11th to 20th	Night	66% 5% 7% 11% 10%	5208
	21st to end	Night	73% 4 5% 11% 7%	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	19% 23% 38% 18% 3 1	200
	11th to 20th	Day	26% 15% 38% 16% 4 2	200
	21st to end	Day	24% 18% 33% 19% 5%	303
February	1st to 10th	Day	26% 29% 32% 10% 3 1	300
	11th to 20th	Day	27% 27% 38% 7% 1	300
	21st to end	Day	32% 18% 36% 13% 1	330
March	1st to 10th	Day	26% 23% 33% 15% 3	500
	11th to 20th	Day	26% 18% 32% 18% 5% 1	500
	21st to end	Day	30% 20% 31% 14% 5% 1	550
April	1st to 10th	Day	29% 22% 29% 14% 5% 1	500
	11th to 20th	Day	34% 17% 24% 14% 8% 3	492
	21st to end	Day	29% 17% 33% 14% 5% 2	500
May	1st to 10th	Day	24% 16% 30% 19% 8% 3	503
	11th to 20th	Day	21% 16% 31% 20% 9% 3	527
	21st to end	Day	19% 17% 32% 20% 10% 2	573
June	1st to 10th	Day	23% 13% 35% 20% 8%	530
	11th to 20th	Day	17% 16% 29% 25% 10% 3	530
	21st to end	Day	18% 15% 33% 23% 9% 3	530
July	1st to 10th	Day	12% 8% 34% 34% 10% 2	525
	11th to 20th	Day	13% 12% 33% 27% 12% 3	524
	21st to end	Day	13% 11% 33% 27% 12% 4	576
August	1st to 10th	Day	15% 7% 31% 28% 15% 5%	526
	11th to 20th	Day	16% 6% 28% 27% 18% 5%	519
	21st to end	Day	15% 9% 32% 25% 12% 6%	583
September	1st to 10th	Day	18% 11% 29% 20% 13% 8%	530
	11th to 20th	Day	13% 10% 22% 23% 20% 12%	530
	21st to end	Day	19% 15% 25% 21% 15% 5%	530
October	1st to 10th	Day	24% 17% 23% 20% 14% 3	530
	11th to 20th	Day	27% 22% 28% 16% 6% 1	530
	21st to end	Day	33% 16% 26% 19% 5%	539
November	1st to 10th	Day	29% 17% 33% 15% 5% 1	315
	11th to 20th	Day	27% 23% 34% 9% 7%	220
	21st to end	Day	35% 19% 33% 9% 2 1	220
December	1st to 10th	Day	28% 16% 36% 15% 4	204
	11th to 20th	Day	30% 27% 30% 10% 3 2	200
	21st to end	Day	34% 17% 29% 15% 5% 1	220
January	1st to 10th	Night	23% 19% 35% 18% 4	800
	11th to 20th	Night	25% 16% 31% 22% 6%	800
	21st to end	Night	17% 15% 36% 25% 7% 1	880
February	1st to 10th	Night	19% 19% 38% 19% 4	800
	11th to 20th	Night	21% 19% 38% 18% 3	783
	21st to end	Night	22% 19% 31% 25% 3	660
March	1st to 10th	Night	26% 17% 33% 20% 4	800
	11th to 20th	Night	22% 21% 32% 20% 5% 1	800
	21st to end	Night	21% 16% 34% 22% 7%	880
April	1st to 10th	Night	28% 16% 31% 22% 4	800
	11th to 20th	Night	27% 16% 30% 19% 8%	791
	21st to end	Night	24% 14% 27% 25% 9%	610
May	1st to 10th	Night	21% 11% 30% 29% 8% 1	430
	11th to 20th	Night	22% 10% 33% 26% 9% 1	394
	21st to end	Night	15% 11% 35% 28% 10%	433
June	1st to 10th	Night	18% 7% 37% 33% 5% 1	400
	11th to 20th	Night	18% 10% 29% 33% 11% 1	400
	21st to end	Night	20% 10% 29% 30% 12%	400
July	1st to 10th	Night	11% 7% 33% 36% 11% 2	390
	11th to 20th	Night	12% 8% 26% 39% 14% 1	388
	21st to end	Night	8% 7% 33% 37% 14%	438
August	1st to 10th	Night	12% 4 26% 35% 23% 1	542
	11th to 20th	Night	12% 4 22% 37% 21% 3	594
	21st to end	Night	14% 8% 29% 31% 17% 2	800
September	1st to 10th	Night	16% 7% 31% 28% 18% 2	800
	11th to 20th	Night	16% 7% 23% 30% 21% 4	800
	21st to end	Night	20% 10% 24% 26% 19% 2	800
October	1st to 10th	Night	24% 10% 28% 24% 14% 1	800
	11th to 20th	Night	26% 17% 28% 20% 8% 1	800
	21st to end	Night	27% 17% 28% 23% 5%	880
November	1st to 10th	Night	26% 17% 27% 22% 6% 1	820
	11th to 20th	Night	23% 20% 30% 18% 9% 1	840
	21st to end	Night	30% 19% 24% 23% 4	840
December	1st to 10th	Night	30% 18% 30% 17% 4	809
	11th to 20th	Night	26% 19% 29% 22% 4	800
	21st to end	Night	33% 16% 27% 20% 4 1	880

Page generated at 2025-11-30 01:00:54. Version ac07

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