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 2025-06-10.

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	17% 10% 3 8% 5% 5% 5% 4 5% 6% 32%	119716
	Night	17% 11% 4 9% 5% 4 4 4 5% 6% 30%	118520
Transparency	Day	51% 4 13% 21% 10% 1	123206
	Night	54% 4 11% 19% 10% 1	123191
Seeing	Day	21% 10% 28% 25% 13% 4	15251
	Night	22% 9% 28% 30% 10% 1	24310

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% 19% 5% 14% 5% 4 4 3 4 5% 22%	3597
	11th to 20th	Day	12% 16% 5% 11% 6% 5% 5% 3 5% 6% 24%	3570
	21st to end	Day	11% 15% 6% 11% 6% 6% 5% 4 5% 6% 26%	3960
February	1st to 10th	Day	14% 16% 4 11% 7% 5% 5% 4 4 6% 25%	1775
	11th to 20th	Day	14% 12% 5% 10% 7% 5% 5% 5% 5% 5% 27%	1843
	21st to end	Day	18% 15% 4 9% 6% 5% 3 3 4 5% 27%	1650
March	1st to 10th	Day	18% 13% 5% 11% 6% 4 4 3 4 5% 26%	4476
	11th to 20th	Day	10% 13% 4 11% 6% 5% 5% 4 6% 6% 32%	4740
	21st to end	Day	18% 9% 3 9% 5% 5% 4 3 4 5% 35%	5942
April	1st to 10th	Day	21% 11% 3 7% 5% 4 3 3 5% 5% 33%	2400
	11th to 20th	Day	20% 8% 3 7% 4 4 4 3 5% 5% 36%	2374
	21st to end	Day	22% 9% 3 7% 4 4 4 4 4 6% 32%	2545
May	1st to 10th	Day	24% 10% 3 9% 5% 5% 5% 4 5% 6% 23%	6297
	11th to 20th	Day	19% 9% 4 8% 5% 5% 4 4 5% 7% 31%	6318
	21st to end	Day	22% 8% 2 7% 5% 4 4 4 6% 6% 32%	6949
June	1st to 10th	Day	20% 9% 3 7% 5% 5% 5% 4 6% 7% 31%	2786
	11th to 20th	Day	14% 6% 2 7% 6% 4 5% 4 6% 8% 38%	2660
	21st to end	Day	19% 8% 3 7% 6% 5% 5% 4 6% 7% 31%	2660
July	1st to 10th	Day	11% 6% 3 7% 6% 6% 5% 4 6% 8% 37%	4440
	11th to 20th	Day	13% 6% 2 6% 4 5% 5% 5% 7% 9% 38%	4440
	21st to end	Day	11% 6% 2 5% 4 4 5% 4 6% 8% 45%	4814
August	1st to 10th	Day	14% 6% 3 8% 5% 5% 5% 4 7% 9% 34%	4423
	11th to 20th	Day	14% 6% 3 7% 5% 5% 4 4 5% 9% 39%	3985
	21st to end	Day	16% 4 2 6% 4 4 5% 4 6% 9% 40%	4180
September	1st to 10th	Day	11% 6% 3 6% 4 4 5% 4 6% 8% 42%	2280
	11th to 20th	Day	13% 5% 2 5% 4 4 4 4 5% 7% 49%	2213
	21st to end	Day	17% 5% 2 6% 4 4 4 4 5% 7% 41%	2090
October	1st to 10th	Day	20% 7% 3 7% 5% 4 4 4 5% 5% 37%	1943
	11th to 20th	Day	18% 9% 2 8% 7% 6% 5% 4 5% 6% 30%	1873
	21st to end	Day	23% 11% 3 7% 4 3 4 3 6% 7% 29%	1881
November	1st to 10th	Day	17% 9% 3 6% 6% 5% 4 4 6% 7% 34%	1761
	11th to 20th	Day	17% 10% 4 8% 5% 5% 5% 3 6% 7% 30%	1705
	21st to end	Day	22% 12% 3 8% 6% 6% 6% 4 5% 6% 23%	1600
December	1st to 10th	Day	21% 20% 5% 10% 5% 4 5% 4 5% 5% 17%	2600
	11th to 20th	Day	18% 14% 5% 10% 6% 5% 4 4 5% 4 27%	2986
	21st to end	Day	23% 13% 4 10% 6% 4 5% 3 4 4 23%	3960
January	1st to 10th	Night	14% 21% 9% 11% 5% 5% 4 3 4 5% 20%	6349
	11th to 20th	Night	10% 15% 6% 16% 8% 6% 5% 4 5% 5% 19%	6315
	21st to end	Night	13% 15% 5% 11% 7% 6% 5% 3 5% 6% 24%	6996
February	1st to 10th	Night	14% 15% 5% 11% 7% 5% 4 5% 6% 6% 23%	2621
	11th to 20th	Night	14% 10% 3 10% 6% 5% 6% 4 6% 7% 28%	2442
	21st to end	Night	15% 15% 4 9% 5% 4 4 4 4 5% 31%	1980
March	1st to 10th	Night	21% 13% 3 9% 4 4 4 3 4 5% 29%	5364
	11th to 20th	Night	15% 13% 4 8% 5% 5% 5% 4 6% 7% 30%	5215
	21st to end	Night	16% 10% 3 10% 5% 5% 5% 3 5% 5% 33%	4990
April	1st to 10th	Night	23% 9% 3 6% 5% 4 4 4 5% 6% 31%	2000
	11th to 20th	Night	22% 9% 3 7% 5% 3 4 3 5% 7% 33%	1975
	21st to end	Night	21% 9% 3 6% 5% 4 4 3 5% 5% 35%	1855
May	1st to 10th	Night	25% 10% 3 8% 6% 5% 4 4 5% 6% 24%	3686
	11th to 20th	Night	22% 9% 3 7% 5% 4 4 3 4 6% 33%	3575
	21st to end	Night	18% 10% 3 9% 5% 4 5% 3 5% 7% 31%	3926
June	1st to 10th	Night	20% 7% 2 8% 5% 5% 4 5% 6% 9% 31%	1598
	11th to 20th	Night	16% 7% 3 6% 4 3 4 5% 6% 8% 39%	1520
	21st to end	Night	18% 7% 2 7% 5% 5% 5% 4 6% 7% 34%	1520
July	1st to 10th	Night	14% 7% 3 7% 5% 5% 5% 4 7% 7% 35%	2520
	11th to 20th	Night	14% 5% 3 7% 5% 4 4 4 6% 9% 41%	2520
	21st to end	Night	11% 7% 3 5% 5% 5% 4 3 6% 8% 44%	2739
August	1st to 10th	Night	15% 7% 3 8% 4 4 4 4 5% 8% 38%	2506
	11th to 20th	Night	15% 7% 3 7% 4 5% 4 4 5% 7% 39%	2807
	21st to end	Night	16% 6% 3 7% 5% 5% 4 4 6% 6% 40%	3476
September	1st to 10th	Night	11% 5% 3 7% 5% 4 5% 4 5% 8% 43%	1900
	11th to 20th	Night	15% 6% 2 5% 4 3 3 2 4 7% 50%	1966
	21st to end	Night	16% 6% 2 5% 4 4 4 3 5% 7% 43%	2090
October	1st to 10th	Night	18% 7% 3 7% 4 4 4 4 5% 6% 37%	2233
	11th to 20th	Night	20% 8% 3 8% 5% 5% 4 4 4 6% 35%	2305
	21st to end	Night	22% 8% 3 8% 5% 5% 5% 3 5% 6% 30%	2717
November	1st to 10th	Night	19% 10% 3 7% 5% 4 4 4 5% 7% 32%	2537
	11th to 20th	Night	18% 10% 3 9% 5% 4 4 4 6% 5% 32%	2693
	21st to end	Night	22% 13% 5% 9% 5% 4 4 3 4 6% 25%	2800
December	1st to 10th	Night	18% 17% 5% 12% 6% 5% 5% 4 5% 5% 19%	4580
	11th to 20th	Night	23% 14% 4 10% 6% 4 4 4 5% 4 23%	5208
	21st to end	Night	25% 16% 4 9% 4 3 3 4 6% 4 23%	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	65% 3 12% 16% 4	3598
	11th to 20th	Day	60% 4 11% 16% 7% 1	3600
	21st to end	Day	58% 4 13% 14% 10% 1	3960
February	1st to 10th	Day	60% 4 9% 19% 6% 2	1775
	11th to 20th	Day	57% 4 13% 17% 8% 1	1852
	21st to end	Day	60% 3 10% 16% 10% 2	1650
March	1st to 10th	Day	61% 3 8% 15% 10% 3	4479
	11th to 20th	Day	52% 4 17% 15% 11% 2	4740
	21st to end	Day	52% 3 8% 17% 18% 2	5942
April	1st to 10th	Day	53% 5% 7% 21% 13% 2	2400
	11th to 20th	Day	49% 3 8% 22% 16% 1	2374
	21st to end	Day	54% 3 9% 18% 13% 3	2545
May	1st to 10th	Day	61% 4 9% 19% 7% 1	6308
	11th to 20th	Day	53% 4 14% 19% 9% 2	6322
	21st to end	Day	51% 4 12% 20% 12% 1	6949
June	1st to 10th	Day	51% 5% 11% 20% 13% 1	2786
	11th to 20th	Day	43% 5% 12% 23% 14% 3	2660
	21st to end	Day	51% 5% 14% 20% 10% 1	2660
July	1st to 10th	Day	42% 5% 14% 27% 11%	4370
	11th to 20th	Day	40% 5% 17% 31% 8%	4365
	21st to end	Day	36% 6% 14% 34% 10%	4661
August	1st to 10th	Day	45% 5% 17% 24% 8%	4409
	11th to 20th	Day	42% 5% 18% 29% 6%	4027
	21st to end	Day	39% 6% 18% 23% 14% 1	4180
September	1st to 10th	Day	37% 6% 15% 29% 13%	2280
	11th to 20th	Day	35% 4 13% 32% 15% 1	2213
	21st to end	Day	42% 5% 14% 27% 11% 1	2090
October	1st to 10th	Day	46% 4 13% 28% 9%	3229
	11th to 20th	Day	44% 3 18% 27% 7%	3089
	21st to end	Day	44% 4 20% 23% 8% 1	3081
November	1st to 10th	Day	48% 5% 15% 23% 8% 1	1761
	11th to 20th	Day	53% 5% 11% 20% 11% 1	1705
	21st to end	Day	60% 6% 13% 16% 5% 1	1600
December	1st to 10th	Day	69% 4 10% 14% 2	2600
	11th to 20th	Day	60% 6% 9% 17% 8%	2986
	21st to end	Day	64% 4 11% 15% 6%	3960
January	1st to 10th	Night	69% 2 12% 13% 4	6349
	11th to 20th	Night	66% 4 11% 14% 4	6360
	21st to end	Night	61% 3 11% 12% 12% 1	6996
February	1st to 10th	Night	61% 5% 9% 17% 7% 1	2621
	11th to 20th	Night	54% 5% 12% 20% 8% 1	2444
	21st to end	Night	56% 3 9% 18% 13% 1	1980
March	1st to 10th	Night	58% 3 7% 16% 12% 4	5374
	11th to 20th	Night	53% 4 14% 16% 11% 2	5216
	21st to end	Night	54% 3 6% 22% 13% 2	4990
April	1st to 10th	Night	54% 3 8% 19% 14% 2	2000
	11th to 20th	Night	53% 4 7% 20% 14% 2	1975
	21st to end	Night	51% 4 7% 20% 14% 4	1855
May	1st to 10th	Night	61% 4 10% 17% 7% 2	3692
	11th to 20th	Night	52% 4 11% 21% 11% 2	3576
	21st to end	Night	53% 3 11% 18% 14% 1	3927
June	1st to 10th	Night	51% 5% 10% 20% 12% 1	1598
	11th to 20th	Night	42% 4 12% 23% 16% 2	1520
	21st to end	Night	48% 5% 13% 19% 14% 1	1520
July	1st to 10th	Night	46% 5% 14% 21% 13%	2480
	11th to 20th	Night	40% 5% 17% 29% 9%	2472
	21st to end	Night	38% 5% 17% 26% 13%	2651
August	1st to 10th	Night	44% 5% 15% 28% 9%	2496
	11th to 20th	Night	44% 5% 19% 24% 8%	2831
	21st to end	Night	43% 5% 15% 22% 13% 1	3476
September	1st to 10th	Night	39% 6% 11% 27% 16% 1	1900
	11th to 20th	Night	36% 3 13% 34% 13% 1	1966
	21st to end	Night	41% 6% 11% 27% 14%	2090
October	1st to 10th	Night	44% 5% 13% 27% 10% 1	3727
	11th to 20th	Night	44% 4 13% 31% 9%	3828
	21st to end	Night	47% 4 18% 19% 12% 1	4467
November	1st to 10th	Night	52% 4 12% 22% 9% 1	2537
	11th to 20th	Night	52% 5% 12% 19% 10% 1	2693
	21st to end	Night	61% 6% 11% 16% 6%	2800
December	1st to 10th	Night	68% 4 12% 12% 4	4580
	11th to 20th	Night	63% 4 8% 15% 10%	5208
	21st to end	Night	64% 3 9% 15% 9%	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	25% 14% 29% 23% 10% 1	200
	11th to 20th	Day	27% 13% 33% 21% 7% 1	200
	21st to end	Day	20% 14% 35% 22% 8% 1	220
February	1st to 10th	Day	29% 17% 35% 15% 5%	287
	11th to 20th	Day	23% 12% 40% 22% 3	390
	21st to end	Day	27% 11% 30% 29% 4	414
March	1st to 10th	Day	24% 11% 35% 23% 7%	500
	11th to 20th	Day	19% 13% 37% 23% 6% 2	500
	21st to end	Day	25% 11% 31% 19% 12% 2	550
April	1st to 10th	Day	28% 13% 26% 22% 9% 2	500
	11th to 20th	Day	25% 14% 27% 20% 11% 3	492
	21st to end	Day	27% 11% 29% 21% 10% 2	500
May	1st to 10th	Day	23% 9% 29% 26% 10% 3	503
	11th to 20th	Day	18% 7% 31% 24% 16% 4	527
	21st to end	Day	20% 9% 28% 26% 13% 5%	573
June	1st to 10th	Day	20% 9% 26% 29% 12% 4	526
	11th to 20th	Day	16% 8% 25% 31% 17% 2	490
	21st to end	Day	22% 7% 25% 25% 15% 5%	490
July	1st to 10th	Day	10% 8% 25% 31% 20% 7%	485
	11th to 20th	Day	13% 6% 26% 31% 18% 6%	484
	21st to end	Day	13% 6% 21% 36% 19% 5%	532
August	1st to 10th	Day	15% 5% 20% 31% 21% 7%	486
	11th to 20th	Day	12% 4 20% 33% 22% 10%	479
	21st to end	Day	14% 6% 25% 25% 20% 9%	539
September	1st to 10th	Day	15% 7% 24% 26% 19% 9%	490
	11th to 20th	Day	13% 6% 21% 25% 21% 13%	490
	21st to end	Day	18% 8% 25% 24% 19% 6%	490
October	1st to 10th	Day	21% 9% 25% 25% 14% 6%	490
	11th to 20th	Day	20% 12% 30% 23% 13% 2	475
	21st to end	Day	29% 13% 24% 24% 9%	429
November	1st to 10th	Day	27% 13% 23% 27% 9% 1	395
	11th to 20th	Day	22% 15% 35% 20% 8% 1	305
	21st to end	Day	27% 16% 32% 19% 7% 1	200
December	1st to 10th	Day	31% 9% 29% 24% 7% 2	200
	11th to 20th	Day	25% 14% 39% 17% 5% 1	200
	21st to end	Day	30% 12% 30% 20% 5% 3	220
January	1st to 10th	Night	25% 12% 31% 27% 5%	800
	11th to 20th	Night	27% 9% 33% 25% 6% 1	800
	21st to end	Night	19% 10% 35% 28% 8% 1	880
February	1st to 10th	Night	20% 11% 36% 26% 6% 1	800
	11th to 20th	Night	21% 11% 36% 27% 5%	783
	21st to end	Night	22% 9% 34% 30% 5%	660
March	1st to 10th	Night	24% 12% 31% 28% 6%	800
	11th to 20th	Night	25% 10% 31% 28% 6% 1	800
	21st to end	Night	22% 10% 28% 30% 9%	880
April	1st to 10th	Night	27% 10% 27% 29% 6%	800
	11th to 20th	Night	25% 12% 30% 27% 6% 1	791
	21st to end	Night	27% 9% 28% 27% 9%	655
May	1st to 10th	Night	26% 6% 29% 29% 9% 2	440
	11th to 20th	Night	21% 7% 26% 34% 11% 1	394
	21st to end	Night	16% 6% 30% 37% 10%	433
June	1st to 10th	Night	25% 4 27% 34% 10% 1	400
	11th to 20th	Night	17% 5% 25% 36% 16% 1	380
	21st to end	Night	19% 6% 26% 32% 17% 1	380
July	1st to 10th	Night	12% 4 24% 40% 19% 1	370
	11th to 20th	Night	11% 3 24% 44% 17% 1	368
	21st to end	Night	13% 4 21% 42% 17% 1	416
August	1st to 10th	Night	16% 3 15% 44% 21% 1	378
	11th to 20th	Night	14% 3 19% 36% 25% 3	570
	21st to end	Night	15% 3 22% 35% 22% 2	836
September	1st to 10th	Night	14% 4 23% 39% 19% 1	760
	11th to 20th	Night	18% 5% 17% 35% 23% 3	760
	21st to end	Night	19% 6% 23% 31% 19% 2	760
October	1st to 10th	Night	21% 7% 26% 31% 14% 1	760
	11th to 20th	Night	23% 9% 28% 29% 11% 1	760
	21st to end	Night	26% 10% 30% 28% 6%	836
November	1st to 10th	Night	25% 12% 28% 27% 8% 1	780
	11th to 20th	Night	23% 13% 33% 21% 9% 1	800
	21st to end	Night	29% 13% 29% 21% 7% 1	800
December	1st to 10th	Night	30% 10% 31% 24% 5%	800
	11th to 20th	Night	29% 14% 29% 23% 5% 1	800
	21st to end	Night	34% 10% 27% 23% 5%	880

Page generated at 2025-06-07 10:28:13. Version ac07

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