Le Golf Sélect de Mirabel
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Le Golf Sélect de Mirabel clear sky chart from 2005-11-06 to 2025-07-21.

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% 31%	120307
	Night	17% 12% 4 9% 5% 4 4 3 5% 6% 31%	118825
Transparency	Day	51% 7% 12% 19% 10% 1	123784
	Night	52% 6% 11% 18% 10% 1	123509
Seeing	Day	23% 16% 31% 20% 8% 2	15386
	Night	23% 13% 30% 25% 8% 1	24368

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% 21% 5% 15% 5% 4 4 3 3 4 21%	3597
	11th to 20th	Day	13% 15% 6% 12% 7% 5% 5% 4 5% 6% 24%	3570
	21st to end	Day	10% 18% 6% 11% 6% 5% 6% 4 5% 4 25%	3960
February	1st to 10th	Day	13% 15% 5% 12% 7% 5% 5% 3 5% 5% 25%	1780
	11th to 20th	Day	14% 14% 4 10% 7% 6% 4 4 6% 6% 25%	1829
	21st to end	Day	18% 15% 5% 9% 6% 5% 5% 3 5% 5% 25%	1650
March	1st to 10th	Day	18% 15% 5% 11% 6% 5% 4 3 4 4 25%	4476
	11th to 20th	Day	11% 14% 4 9% 5% 5% 4 4 6% 7% 31%	4764
	21st to end	Day	19% 9% 4 9% 5% 4 4 3 4 4 35%	5919
April	1st to 10th	Day	21% 11% 3 8% 5% 4 4 3 4 5% 33%	2400
	11th to 20th	Day	21% 9% 3 7% 4 4 4 3 5% 5% 35%	2374
	21st to end	Day	22% 9% 3 7% 5% 4 4 4 4 5% 32%	2540
May	1st to 10th	Day	26% 11% 3 9% 5% 5% 5% 4 5% 6% 22%	6343
	11th to 20th	Day	19% 9% 3 8% 5% 5% 5% 3 5% 6% 30%	6318
	21st to end	Day	22% 8% 2 7% 5% 4 5% 4 6% 7% 31%	6949
June	1st to 10th	Day	20% 8% 3 8% 5% 5% 5% 4 6% 7% 29%	2800
	11th to 20th	Day	14% 7% 3 6% 5% 6% 5% 4 6% 8% 36%	2800
	21st to end	Day	19% 8% 3 7% 6% 6% 5% 4 6% 7% 28%	2800
July	1st to 10th	Day	12% 7% 2 7% 6% 6% 6% 5% 6% 9% 35%	4580
	11th to 20th	Day	14% 5% 3 6% 5% 5% 6% 4 7% 8% 36%	4580
	21st to end	Day	11% 5% 2 5% 4 4 4 4 7% 8% 45%	4814
August	1st to 10th	Day	14% 6% 2 8% 5% 5% 6% 5% 6% 9% 33%	4423
	11th to 20th	Day	14% 7% 3 6% 5% 4 5% 4 6% 8% 37%	3992
	21st to end	Day	16% 5% 2 6% 5% 5% 5% 4 6% 9% 39%	4180
September	1st to 10th	Day	13% 6% 2 6% 4 5% 5% 4 7% 8% 41%	2280
	11th to 20th	Day	13% 5% 2 5% 4 4 4 3 5% 7% 49%	2219
	21st to end	Day	17% 6% 2 5% 4 4 3 3 6% 7% 41%	2090
October	1st to 10th	Day	21% 7% 3 7% 4 3 3 4 5% 6% 36%	1929
	11th to 20th	Day	21% 8% 3 8% 6% 5% 5% 4 5% 6% 29%	1878
	21st to end	Day	23% 10% 3 7% 4 5% 4 4 5% 6% 28%	1881
November	1st to 10th	Day	15% 9% 3 8% 5% 5% 5% 4 6% 7% 33%	1761
	11th to 20th	Day	18% 10% 3 8% 4 6% 6% 4 6% 7% 29%	1685
	21st to end	Day	22% 12% 3 8% 5% 5% 5% 4 5% 6% 24%	1600
December	1st to 10th	Day	19% 21% 5% 11% 5% 5% 4 4 5% 5% 18%	2600
	11th to 20th	Day	18% 17% 5% 9% 5% 4 4 4 4 4 27%	2986
	21st to end	Day	23% 14% 5% 9% 5% 4 4 3 4 4 24%	3960
January	1st to 10th	Night	13% 22% 7% 13% 5% 4 4 3 4 4 20%	6349
	11th to 20th	Night	9% 16% 7% 16% 8% 6% 4 3 5% 5% 20%	6315
	21st to end	Night	12% 15% 6% 12% 7% 5% 4 4 4 5% 25%	6996
February	1st to 10th	Night	13% 13% 5% 11% 6% 5% 5% 4 6% 6% 26%	2618
	11th to 20th	Night	13% 12% 5% 10% 7% 5% 4 4 6% 6% 29%	2456
	21st to end	Night	14% 15% 4 9% 5% 4 4 3 5% 5% 30%	1980
March	1st to 10th	Night	22% 14% 4 8% 5% 4 4 3 4 5% 29%	5364
	11th to 20th	Night	13% 14% 3 8% 5% 5% 5% 3 6% 7% 30%	5191
	21st to end	Night	16% 11% 4 9% 5% 5% 5% 4 4 4 33%	5012
April	1st to 10th	Night	22% 10% 3 7% 4 4 4 3 4 6% 33%	2000
	11th to 20th	Night	20% 9% 3 7% 4 5% 5% 2 5% 6% 35%	1975
	21st to end	Night	21% 10% 2 6% 4 4 4 4 5% 5% 35%	1860
May	1st to 10th	Night	23% 9% 3 9% 6% 5% 5% 3 5% 6% 26%	3640
	11th to 20th	Night	21% 8% 3 7% 4 4 4 4 5% 6% 35%	3575
	21st to end	Night	20% 10% 3 8% 4 4 5% 3 5% 7% 30%	3926
June	1st to 10th	Night	19% 8% 2 6% 5% 5% 4 4 7% 8% 32%	1600
	11th to 20th	Night	16% 8% 3 6% 5% 4 4 4 5% 7% 40%	1600
	21st to end	Night	19% 7% 2 6% 5% 4 6% 4 6% 6% 36%	1600
July	1st to 10th	Night	13% 7% 3 8% 5% 5% 6% 5% 6% 7% 36%	2600
	11th to 20th	Night	14% 7% 2 6% 4 4 4 4 5% 9% 41%	2600
	21st to end	Night	12% 6% 2 6% 4 4 5% 4 6% 8% 44%	2739
August	1st to 10th	Night	15% 7% 3 7% 5% 4 5% 4 5% 8% 38%	2506
	11th to 20th	Night	16% 7% 3 6% 4 4 5% 4 6% 6% 40%	2800
	21st to end	Night	17% 5% 3 7% 4 4 4 4 5% 6% 42%	3476
September	1st to 10th	Night	11% 5% 3 7% 4 4 5% 3 6% 7% 45%	1900
	11th to 20th	Night	14% 6% 2 5% 3 3 4 3 4 7% 50%	1959
	21st to end	Night	17% 6% 2 5% 4 4 3 3 5% 7% 45%	2090
October	1st to 10th	Night	18% 8% 3 6% 4 4 5% 3 5% 6% 39%	2247
	11th to 20th	Night	21% 8% 2 6% 4 5% 4 2 5% 6% 35%	2300
	21st to end	Night	22% 9% 3 8% 5% 5% 4 3 5% 5% 30%	2717
November	1st to 10th	Night	19% 10% 3 7% 4 4 5% 3 6% 7% 33%	2537
	11th to 20th	Night	17% 11% 3 8% 5% 5% 5% 3 4 5% 33%	2713
	21st to end	Night	20% 14% 4 9% 6% 4 4 3 4 6% 28%	2800
December	1st to 10th	Night	17% 16% 5% 11% 6% 6% 5% 4 5% 5% 20%	4580
	11th to 20th	Night	23% 14% 4 10% 5% 4 3 2 3 4 26%	5208
	21st to end	Night	25% 16% 4 9% 4 3 3 3 4 5% 25%	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	64% 7% 9% 15% 4 1	3598
	11th to 20th	Day	59% 7% 10% 16% 6% 2	3600
	21st to end	Day	59% 7% 11% 13% 11% 1	3960
February	1st to 10th	Day	60% 5% 8% 18% 7% 2	1780
	11th to 20th	Day	59% 6% 10% 15% 9% 1	1838
	21st to end	Day	60% 4 9% 14% 11% 2	1650
March	1st to 10th	Day	61% 5% 7% 12% 11% 3	4479
	11th to 20th	Day	50% 6% 16% 14% 11% 2	4764
	21st to end	Day	52% 4 7% 15% 19% 2	5919
April	1st to 10th	Day	54% 4 8% 18% 13% 3	2400
	11th to 20th	Day	50% 5% 7% 21% 16% 2	2374
	21st to end	Day	54% 6% 8% 16% 13% 3	2540
May	1st to 10th	Day	61% 6% 7% 17% 8% 1	6354
	11th to 20th	Day	51% 7% 13% 17% 9% 2	6322
	21st to end	Day	51% 6% 11% 19% 12% 1	6949
June	1st to 10th	Day	52% 7% 9% 18% 12% 1	2800
	11th to 20th	Day	43% 7% 12% 22% 13% 3	2800
	21st to end	Day	52% 8% 11% 18% 9% 1	2800
July	1st to 10th	Day	43% 9% 14% 24% 10%	4510
	11th to 20th	Day	40% 9% 15% 28% 8%	4505
	21st to end	Day	35% 7% 15% 32% 10%	4661
August	1st to 10th	Day	45% 9% 16% 21% 9%	4409
	11th to 20th	Day	42% 9% 16% 26% 7%	4034
	21st to end	Day	40% 8% 18% 20% 14% 1	4180
September	1st to 10th	Day	39% 8% 13% 27% 13%	2280
	11th to 20th	Day	35% 6% 14% 31% 14% 1	2219
	21st to end	Day	41% 7% 14% 26% 11%	2090
October	1st to 10th	Day	44% 8% 14% 24% 10%	3202
	11th to 20th	Day	45% 6% 17% 24% 7%	3094
	21st to end	Day	44% 7% 21% 19% 8%	3081
November	1st to 10th	Day	49% 6% 15% 21% 8% 1	1761
	11th to 20th	Day	53% 6% 12% 17% 11% 1	1685
	21st to end	Day	60% 8% 13% 13% 5% 1	1600
December	1st to 10th	Day	68% 6% 10% 13% 3	2600
	11th to 20th	Day	60% 6% 9% 16% 9%	2986
	21st to end	Day	62% 6% 9% 15% 7%	3960
January	1st to 10th	Night	66% 7% 11% 12% 4	6349
	11th to 20th	Night	62% 8% 10% 14% 5%	6360
	21st to end	Night	60% 6% 10% 11% 13% 1	6996
February	1st to 10th	Night	58% 5% 10% 18% 8% 1	2618
	11th to 20th	Night	55% 6% 12% 19% 8% 1	2458
	21st to end	Night	55% 5% 10% 16% 13% 1	1980
March	1st to 10th	Night	58% 4 8% 14% 12% 4	5374
	11th to 20th	Night	50% 7% 14% 15% 10% 3	5192
	21st to end	Night	53% 5% 7% 20% 13% 2	5012
April	1st to 10th	Night	52% 5% 8% 18% 14% 2	2000
	11th to 20th	Night	49% 5% 7% 21% 15% 2	1975
	21st to end	Night	50% 5% 8% 18% 15% 4	1860
May	1st to 10th	Night	58% 6% 10% 17% 7% 2	3646
	11th to 20th	Night	48% 8% 11% 20% 11% 2	3576
	21st to end	Night	53% 6% 10% 16% 14% 1	3927
June	1st to 10th	Night	48% 7% 10% 21% 13% 1	1600
	11th to 20th	Night	43% 7% 10% 23% 15% 2	1600
	21st to end	Night	46% 8% 12% 19% 14% 1	1600
July	1st to 10th	Night	44% 8% 16% 19% 12% 1	2560
	11th to 20th	Night	39% 7% 17% 29% 8%	2552
	21st to end	Night	36% 8% 17% 25% 14%	2651
August	1st to 10th	Night	43% 8% 13% 27% 9%	2496
	11th to 20th	Night	42% 8% 18% 26% 7%	2824
	21st to end	Night	40% 9% 15% 22% 13% 1	3476
September	1st to 10th	Night	37% 7% 12% 27% 16% 1	1900
	11th to 20th	Night	34% 6% 13% 34% 12% 1	1959
	21st to end	Night	39% 7% 11% 29% 14%	2090
October	1st to 10th	Night	42% 6% 15% 25% 11% 1	3754
	11th to 20th	Night	42% 6% 14% 28% 10%	3823
	21st to end	Night	45% 6% 18% 18% 11% 1	4467
November	1st to 10th	Night	50% 6% 14% 21% 9% 1	2537
	11th to 20th	Night	52% 6% 12% 18% 10% 2	2713
	21st to end	Night	57% 7% 12% 17% 6%	2800
December	1st to 10th	Night	63% 6% 13% 13% 4	4580
	11th to 20th	Night	62% 5% 7% 15% 10% 1	5208
	21st to end	Night	62% 4 7% 14% 12%	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	22% 23% 36% 16% 4	200
	11th to 20th	Day	27% 22% 35% 12% 5% 1	200
	21st to end	Day	22% 19% 38% 17% 4	220
February	1st to 10th	Day	33% 24% 33% 9% 1	290
	11th to 20th	Day	23% 27% 39% 10% 1	376
	21st to end	Day	29% 22% 30% 16% 3	414
March	1st to 10th	Day	28% 19% 33% 17% 4	500
	11th to 20th	Day	26% 23% 33% 14% 3 1	500
	21st to end	Day	28% 22% 27% 14% 7% 1	550
April	1st to 10th	Day	32% 18% 29% 14% 6% 1	500
	11th to 20th	Day	31% 22% 23% 16% 6% 1	492
	21st to end	Day	30% 19% 31% 14% 5% 1	500
May	1st to 10th	Day	26% 18% 33% 17% 5% 1	503
	11th to 20th	Day	23% 18% 31% 21% 6% 2	527
	21st to end	Day	24% 17% 31% 20% 7% 1	573
June	1st to 10th	Day	23% 17% 34% 19% 7%	530
	11th to 20th	Day	18% 16% 33% 23% 9% 2	530
	21st to end	Day	25% 14% 32% 21% 7% 2	530
July	1st to 10th	Day	13% 12% 36% 25% 10% 4	525
	11th to 20th	Day	16% 9% 35% 29% 9% 2	524
	21st to end	Day	15% 9% 35% 28% 12% 2	532
August	1st to 10th	Day	17% 8% 27% 32% 14% 2	486
	11th to 20th	Day	12% 11% 25% 30% 15% 6%	479
	21st to end	Day	16% 11% 31% 22% 14% 6%	539
September	1st to 10th	Day	16% 8% 35% 23% 12% 5%	490
	11th to 20th	Day	12% 9% 27% 25% 19% 8%	490
	21st to end	Day	20% 13% 27% 23% 13% 4	490
October	1st to 10th	Day	24% 15% 28% 20% 12% 1	490
	11th to 20th	Day	23% 19% 29% 19% 8% 1	477
	21st to end	Day	31% 15% 29% 20% 4	429
November	1st to 10th	Day	29% 17% 29% 19% 6% 1	395
	11th to 20th	Day	27% 18% 36% 15% 5%	285
	21st to end	Day	31% 20% 33% 15% 3	200
December	1st to 10th	Day	31% 16% 28% 21% 4 1	200
	11th to 20th	Day	31% 26% 29% 12% 2 1	200
	21st to end	Day	33% 19% 27% 16% 4 1	220
January	1st to 10th	Night	26% 15% 35% 21% 4	800
	11th to 20th	Night	26% 18% 31% 19% 6% 1	800
	21st to end	Night	18% 15% 38% 24% 5%	880
February	1st to 10th	Night	19% 18% 37% 22% 3	800
	11th to 20th	Night	22% 17% 38% 19% 4	783
	21st to end	Night	23% 17% 32% 25% 3	660
March	1st to 10th	Night	23% 16% 35% 23% 3	800
	11th to 20th	Night	24% 17% 34% 20% 5%	800
	21st to end	Night	24% 14% 32% 24% 6%	880
April	1st to 10th	Night	29% 15% 28% 25% 4	800
	11th to 20th	Night	26% 14% 33% 23% 5% 1	791
	21st to end	Night	28% 12% 33% 18% 8%	660
May	1st to 10th	Night	25% 11% 33% 23% 6% 3	420
	11th to 20th	Night	21% 11% 31% 28% 9% 1	394
	21st to end	Night	17% 11% 37% 28% 7%	433
June	1st to 10th	Night	23% 10% 30% 29% 9% 1	400
	11th to 20th	Night	20% 6% 31% 32% 10% 1	400
	21st to end	Night	21% 6% 30% 30% 13% 1	400
July	1st to 10th	Night	11% 8% 29% 37% 14% 1	390
	11th to 20th	Night	13% 7% 22% 42% 16%	388
	21st to end	Night	14% 4 28% 38% 14% 1	416
August	1st to 10th	Night	15% 3 22% 42% 18% 1	378
	11th to 20th	Night	13% 4 24% 34% 22% 2	563
	21st to end	Night	15% 7% 24% 34% 18% 2	836
September	1st to 10th	Night	14% 6% 29% 37% 14% 1	760
	11th to 20th	Night	17% 7% 20% 32% 24% 1	760
	21st to end	Night	20% 6% 27% 28% 16% 2	760
October	1st to 10th	Night	23% 9% 26% 30% 11% 1	760
	11th to 20th	Night	26% 12% 28% 26% 7% 1	760
	21st to end	Night	28% 13% 29% 25% 5%	836
November	1st to 10th	Night	26% 15% 28% 24% 7% 1	780
	11th to 20th	Night	23% 16% 33% 20% 8%	800
	21st to end	Night	32% 15% 28% 18% 6%	800
December	1st to 10th	Night	28% 15% 32% 20% 5%	800
	11th to 20th	Night	30% 18% 29% 18% 4 1	800
	21st to end	Night	35% 15% 27% 18% 5%	880

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