Parc national d'Oka
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Parc national d'Oka clear sky chart from 2005-11-06 to 2026-10-14.

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% 9% 3 8% 5% 5% 5% 4 5% 7% 33%	149918
	Night	17% 11% 4 9% 5% 5% 4 4 5% 6% 30%	141849
Transparency	Day	49% 4 13% 22% 10% 1	153365
	Night	53% 4 12% 20% 10% 1	146491
Seeing	Day	20% 10% 28% 25% 13% 4	17017
	Night	22% 9% 28% 29% 10% 1	25922

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	15% 17% 5% 14% 5% 4 5% 3 5% 5% 22%	4661
	11th to 20th	Day	12% 16% 6% 13% 7% 6% 5% 3 5% 6% 22%	4650
	21st to end	Day	9% 13% 5% 12% 9% 7% 6% 4 5% 5% 23%	5124
February	1st to 10th	Day	13% 15% 4 11% 6% 5% 5% 4 4 6% 26%	1864
	11th to 20th	Day	14% 12% 5% 10% 7% 5% 5% 5% 5% 5% 27%	1938
	21st to end	Day	17% 16% 5% 10% 6% 5% 3 3 4 5% 27%	1730
March	1st to 10th	Day	18% 13% 5% 11% 6% 4 4 3 4 5% 26%	4576
	11th to 20th	Day	10% 13% 4 11% 6% 5% 5% 4 6% 6% 31%	4844
	21st to end	Day	18% 9% 4 9% 5% 5% 4 3 4 5% 34%	6073
April	1st to 10th	Day	21% 11% 3 7% 5% 4 3 3 5% 5% 32%	2520
	11th to 20th	Day	21% 8% 3 7% 4 4 4 3 5% 5% 35%	2494
	21st to end	Day	21% 9% 3 7% 4 4 4 4 4 6% 32%	2672
May	1st to 10th	Day	22% 9% 3 9% 5% 5% 6% 4 6% 8% 24%	8174
	11th to 20th	Day	18% 8% 4 8% 4 5% 4 3 5% 7% 33%	8221
	21st to end	Day	21% 9% 2 7% 4 4 4 3 5% 6% 34%	9060
June	1st to 10th	Day	20% 8% 3 7% 4 5% 5% 4 6% 7% 31%	2940
	11th to 20th	Day	14% 6% 3 7% 6% 5% 5% 4 6% 8% 37%	2940
	21st to end	Day	18% 8% 3 7% 5% 5% 5% 4 6% 7% 32%	2940
July	1st to 10th	Day	10% 6% 2 8% 5% 6% 6% 4 6% 9% 38%	8280
	11th to 20th	Day	10% 5% 2 5% 4 5% 5% 4 6% 9% 46%	8280
	21st to end	Day	11% 6% 2 6% 4 5% 5% 4 7% 10% 42%	8993
August	1st to 10th	Day	15% 7% 3 8% 5% 5% 5% 4 7% 8% 33%	6483
	11th to 20th	Day	12% 7% 3 7% 5% 5% 5% 4 6% 8% 38%	5863
	21st to end	Day	13% 5% 2 7% 5% 5% 5% 4 7% 10% 38%	6080
September	1st to 10th	Day	12% 6% 2 6% 4 4 5% 4 6% 9% 43%	2520
	11th to 20th	Day	12% 5% 2 5% 4 4 4 4 5% 7% 50%	2445
	21st to end	Day	17% 5% 2 6% 4 4 4 4 5% 7% 41%	2310
October	1st to 10th	Day	19% 6% 3 7% 4 4 4 4 5% 6% 38%	2147
	11th to 20th	Day	18% 9% 2 8% 6% 6% 5% 4 5% 6% 31%	2001
	21st to end	Day	23% 11% 3 7% 4 3 4 3 6% 7% 29%	1980
November	1st to 10th	Day	16% 10% 3 7% 5% 5% 4 4 6% 7% 33%	1851
	11th to 20th	Day	17% 10% 5% 8% 5% 5% 5% 3 6% 6% 29%	1790
	21st to end	Day	22% 13% 3 8% 5% 6% 6% 4 5% 5% 23%	1680
December	1st to 10th	Day	20% 20% 5% 10% 5% 4 5% 4 5% 5% 17%	2680
	11th to 20th	Day	17% 14% 5% 10% 6% 5% 4 4 4 4 26%	3066
	21st to end	Day	23% 13% 4 10% 6% 4 6% 3 4 4 23%	4048
January	1st to 10th	Night	13% 19% 8% 12% 5% 4 4 3 4 5% 21%	8234
	11th to 20th	Night	12% 16% 6% 17% 8% 6% 5% 4 4 5% 17%	8235
	21st to end	Night	11% 14% 5% 12% 8% 6% 5% 3 5% 6% 26%	9057
February	1st to 10th	Night	13% 14% 5% 11% 7% 5% 4 5% 6% 6% 24%	2752
	11th to 20th	Night	14% 10% 4 10% 6% 5% 6% 4 6% 7% 28%	2567
	21st to end	Night	14% 15% 4 9% 5% 5% 4 4 4 5% 31%	2076
March	1st to 10th	Night	21% 13% 3 9% 4 4 4 3 4 5% 29%	5484
	11th to 20th	Night	15% 13% 4 8% 5% 5% 5% 4 6% 7% 29%	5330
	21st to end	Night	16% 10% 3 10% 5% 5% 5% 4 5% 5% 32%	5101
April	1st to 10th	Night	23% 9% 3 6% 5% 4 4 4 5% 6% 31%	2100
	11th to 20th	Night	22% 9% 3 8% 5% 3 4 3 5% 7% 32%	2075
	21st to end	Night	21% 9% 3 6% 5% 4 4 3 5% 5% 35%	1948
May	1st to 10th	Night	22% 9% 3 8% 6% 5% 4 4 6% 8% 25%	4780
	11th to 20th	Night	20% 9% 3 7% 5% 5% 5% 3 5% 6% 33%	4639
	21st to end	Night	18% 9% 3 8% 4 4 5% 3 5% 8% 32%	5114
June	1st to 10th	Night	19% 7% 2 8% 5% 5% 4 5% 6% 9% 31%	1680
	11th to 20th	Night	16% 7% 3 6% 4 3 4 5% 6% 8% 39%	1680
	21st to end	Night	18% 7% 2 7% 5% 5% 5% 3 6% 7% 35%	1680
July	1st to 10th	Night	12% 6% 3 7% 5% 5% 6% 5% 7% 9% 34%	4680
	11th to 20th	Night	12% 5% 2 6% 4 4 4 4 5% 9% 44%	4680
	21st to end	Night	12% 6% 3 6% 5% 5% 5% 4 6% 8% 41%	5084
August	1st to 10th	Night	16% 8% 3 8% 4 4 5% 4 6% 7% 35%	3666
	11th to 20th	Night	15% 7% 3 7% 4 4 4 4 5% 7% 39%	4132
	21st to end	Night	13% 6% 3 7% 5% 5% 5% 4 6% 7% 40%	5045
September	1st to 10th	Night	12% 5% 3 7% 5% 4 4 4 6% 8% 42%	2100
	11th to 20th	Night	14% 6% 2 5% 3 3 3 2 4 7% 50%	2174
	21st to end	Night	16% 6% 2 5% 4 4 4 3 5% 7% 43%	2310
October	1st to 10th	Night	18% 7% 2 6% 4 4 4 4 5% 6% 39%	2469
	11th to 20th	Night	19% 8% 3 8% 5% 5% 4 4 4 6% 35%	2464
	21st to end	Night	22% 8% 3 8% 5% 5% 5% 3 5% 6% 31%	2860
November	1st to 10th	Night	20% 10% 3 7% 5% 4 4 4 5% 7% 32%	2667
	11th to 20th	Night	18% 11% 3 9% 5% 4 4 4 6% 5% 32%	2828
	21st to end	Night	21% 13% 5% 9% 5% 4 4 3 4 5% 25%	2940
December	1st to 10th	Night	17% 17% 5% 11% 6% 5% 5% 4 5% 5% 19%	4720
	11th to 20th	Night	22% 15% 4 10% 6% 4 4 3 5% 4 23%	5348
	21st to end	Night	25% 16% 4 9% 4 3 3 4 5% 4 23%	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	64% 3 13% 16% 4	4662
	11th to 20th	Day	61% 4 9% 15% 10% 1	4680
	21st to end	Day	61% 5% 11% 12% 10% 1	5124
February	1st to 10th	Day	59% 4 9% 20% 6% 2	1864
	11th to 20th	Day	57% 4 12% 18% 8% 1	1947
	21st to end	Day	61% 3 9% 15% 9% 2	1730
March	1st to 10th	Day	61% 3 8% 15% 10% 3	4579
	11th to 20th	Day	52% 4 17% 15% 11% 2	4844
	21st to end	Day	52% 3 8% 17% 18% 2	6073
April	1st to 10th	Day	54% 4 7% 21% 12% 2	2520
	11th to 20th	Day	50% 3 8% 22% 16% 1	2494
	21st to end	Day	53% 3 9% 19% 13% 3	2672
May	1st to 10th	Day	57% 4 9% 20% 10% 1	8186
	11th to 20th	Day	50% 4 13% 22% 9% 1	8225
	21st to end	Day	50% 3 11% 23% 11% 1	9061
June	1st to 10th	Day	50% 5% 10% 21% 13% 1	2940
	11th to 20th	Day	44% 5% 12% 23% 14% 3	2940
	21st to end	Day	49% 5% 13% 21% 10% 1	2940
July	1st to 10th	Day	41% 5% 15% 27% 12%	8210
	11th to 20th	Day	34% 4 15% 33% 14%	8205
	21st to end	Day	37% 5% 17% 33% 8%	8795
August	1st to 10th	Day	48% 5% 16% 20% 9% 2	6469
	11th to 20th	Day	42% 5% 18% 28% 7%	5905
	21st to end	Day	39% 6% 20% 24% 11%	6080
September	1st to 10th	Day	36% 6% 14% 31% 12%	2520
	11th to 20th	Day	34% 4 12% 34% 15% 1	2445
	21st to end	Day	42% 5% 13% 26% 12% 1	2310
October	1st to 10th	Day	45% 4 13% 28% 10%	3433
	11th to 20th	Day	44% 4 18% 27% 7%	3217
	21st to end	Day	44% 4 20% 23% 8% 1	3180
November	1st to 10th	Day	49% 5% 15% 22% 8% 1	1851
	11th to 20th	Day	54% 5% 11% 19% 10% 1	1790
	21st to end	Day	61% 6% 13% 15% 5%	1680
December	1st to 10th	Day	69% 4 10% 14% 3	2680
	11th to 20th	Day	60% 6% 9% 17% 8%	3066
	21st to end	Day	64% 4 11% 15% 6%	4048
January	1st to 10th	Night	67% 2 11% 14% 5%	8234
	11th to 20th	Night	69% 4 9% 12% 5%	8280
	21st to end	Night	60% 3 9% 15% 13%	9057
February	1st to 10th	Night	61% 5% 9% 18% 7% 1	2752
	11th to 20th	Night	54% 5% 11% 21% 8% 1	2569
	21st to end	Night	56% 3 9% 18% 13% 1	2076
March	1st to 10th	Night	58% 3 7% 16% 12% 4	5494
	11th to 20th	Night	53% 4 14% 16% 11% 2	5331
	21st to end	Night	54% 3 6% 22% 13% 2	5101
April	1st to 10th	Night	54% 4 8% 19% 13% 2	2100
	11th to 20th	Night	53% 4 7% 21% 14% 2	2075
	21st to end	Night	50% 4 7% 20% 15% 4	1948
May	1st to 10th	Night	57% 4 11% 18% 8% 2	4786
	11th to 20th	Night	52% 4 10% 23% 10% 1	4640
	21st to end	Night	51% 3 10% 19% 16% 1	5115
June	1st to 10th	Night	50% 6% 10% 21% 12% 1	1680
	11th to 20th	Night	43% 4 12% 22% 16% 2	1680
	21st to end	Night	48% 5% 12% 21% 13% 1	1680
July	1st to 10th	Night	44% 5% 17% 22% 12% 1	4640
	11th to 20th	Night	36% 5% 16% 32% 12%	4632
	21st to end	Night	41% 5% 16% 28% 11%	4967
August	1st to 10th	Night	47% 5% 16% 21% 9% 1	3656
	11th to 20th	Night	43% 5% 17% 26% 8%	4156
	21st to end	Night	40% 6% 18% 23% 11% 1	5045
September	1st to 10th	Night	39% 6% 11% 29% 15% 1	2100
	11th to 20th	Night	35% 3 13% 34% 14% 1	2174
	21st to end	Night	41% 5% 10% 26% 16% 1	2310
October	1st to 10th	Night	43% 5% 13% 27% 11% 1	3963
	11th to 20th	Night	44% 4 13% 30% 9%	3987
	21st to end	Night	47% 4 17% 20% 11% 1	4610
November	1st to 10th	Night	52% 4 12% 22% 8% 1	2667
	11th to 20th	Night	53% 5% 12% 19% 10% 1	2828
	21st to end	Night	61% 5% 11% 16% 6%	2940
December	1st to 10th	Night	68% 4 12% 12% 4	4720
	11th to 20th	Night	63% 4 8% 15% 10%	5348
	21st to end	Night	64% 3 8% 15% 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% 13% 31% 22% 10%	220
	11th to 20th	Day	28% 15% 32% 19% 6%	220
	21st to end	Day	19% 15% 34% 23% 9% 1	242
February	1st to 10th	Day	26% 16% 36% 16% 5%	316
	11th to 20th	Day	22% 12% 41% 21% 3	425
	21st to end	Day	26% 11% 31% 28% 3	446
March	1st to 10th	Day	23% 12% 35% 22% 7%	540
	11th to 20th	Day	22% 13% 35% 22% 6% 2	540
	21st to end	Day	24% 13% 31% 18% 11% 2	594
April	1st to 10th	Day	28% 13% 27% 21% 9% 1	540
	11th to 20th	Day	26% 14% 27% 20% 11% 3	532
	21st to end	Day	26% 12% 29% 21% 10% 2	540
May	1st to 10th	Day	23% 10% 29% 26% 9% 3	543
	11th to 20th	Day	19% 9% 30% 23% 15% 4	567
	21st to end	Day	20% 10% 30% 25% 12% 4	617
June	1st to 10th	Day	20% 9% 25% 29% 13% 4	570
	11th to 20th	Day	16% 9% 27% 30% 16% 2	570
	21st to end	Day	21% 7% 28% 26% 15% 4	570
July	1st to 10th	Day	10% 8% 27% 31% 18% 6%	565
	11th to 20th	Day	12% 8% 28% 29% 17% 6%	564
	21st to end	Day	13% 8% 22% 34% 19% 5%	620
August	1st to 10th	Day	14% 5% 23% 30% 21% 7%	566
	11th to 20th	Day	11% 5% 22% 32% 21% 9%	559
	21st to end	Day	14% 7% 26% 25% 20% 8%	627
September	1st to 10th	Day	15% 8% 24% 26% 18% 9%	570
	11th to 20th	Day	12% 6% 22% 26% 22% 12%	570
	21st to end	Day	19% 8% 26% 23% 19% 6%	570
October	1st to 10th	Day	20% 10% 26% 25% 13% 5%	570
	11th to 20th	Day	20% 12% 30% 24% 12% 2	525
	21st to end	Day	28% 12% 25% 25% 10%	462
November	1st to 10th	Day	27% 15% 23% 25% 9% 1	425
	11th to 20th	Day	23% 14% 34% 21% 8% 1	330
	21st to end	Day	29% 15% 31% 18% 6%	220
December	1st to 10th	Day	30% 10% 28% 23% 7% 1	220
	11th to 20th	Day	25% 14% 40% 16% 5% 1	220
	21st to end	Day	29% 12% 32% 19% 5% 2	242
January	1st to 10th	Night	24% 12% 32% 27% 5%	840
	11th to 20th	Night	28% 10% 31% 25% 6%	840
	21st to end	Night	19% 10% 35% 28% 8% 1	924
February	1st to 10th	Night	19% 11% 36% 27% 7% 1	840
	11th to 20th	Night	20% 11% 36% 27% 5%	823
	21st to end	Night	22% 9% 34% 30% 5%	692
March	1st to 10th	Night	24% 12% 31% 27% 6%	840
	11th to 20th	Night	25% 11% 30% 27% 6%	840
	21st to end	Night	23% 11% 28% 29% 9%	924
April	1st to 10th	Night	28% 11% 27% 29% 5%	840
	11th to 20th	Night	25% 11% 30% 27% 6%	831
	21st to end	Night	26% 9% 27% 28% 9%	688
May	1st to 10th	Night	26% 6% 29% 29% 8% 2	462
	11th to 20th	Night	21% 8% 27% 33% 10% 1	414
	21st to end	Night	17% 6% 31% 36% 9%	455
June	1st to 10th	Night	24% 4 27% 35% 11%	420
	11th to 20th	Night	18% 8% 25% 34% 15% 1	420
	21st to end	Night	19% 6% 26% 31% 17% 1	420
July	1st to 10th	Night	12% 4 25% 40% 19% 1	410
	11th to 20th	Night	11% 4 25% 42% 16% 1	408
	21st to end	Night	14% 5% 21% 42% 17% 1	460
August	1st to 10th	Night	15% 4 17% 43% 21% 1	418
	11th to 20th	Night	14% 3 20% 36% 24% 3	632
	21st to end	Night	15% 4 23% 35% 21% 2	924
September	1st to 10th	Night	14% 5% 23% 38% 18% 1	840
	11th to 20th	Night	17% 5% 17% 35% 23% 3	840
	21st to end	Night	19% 6% 24% 30% 19% 2	840
October	1st to 10th	Night	21% 7% 28% 30% 14% 1	840
	11th to 20th	Night	22% 9% 28% 29% 11% 1	813
	21st to end	Night	26% 10% 30% 28% 6%	880
November	1st to 10th	Night	25% 12% 28% 27% 8%	820
	11th to 20th	Night	23% 13% 33% 22% 9% 1	840
	21st to end	Night	29% 13% 30% 20% 7% 1	840
December	1st to 10th	Night	29% 11% 30% 24% 5%	840
	11th to 20th	Night	28% 15% 30% 22% 5% 1	840
	21st to end	Night	35% 11% 27% 22% 5%	924

Page generated at 2026-10-11 05:06:26. Version ac07

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