La Tuque
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Tuque clear sky chart from 2005-11-06 to 2026-03-18.

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% 12% 4 10% 6% 5% 5% 4 5% 6% 26%	130791
	Night	16% 13% 5% 11% 7% 5% 5% 3 5% 5% 24%	130729
Transparency	Day	58% 5% 11% 17% 8% 1	134223
	Night	61% 5% 11% 16% 6% 1	135385
Seeing	Day	26% 17% 30% 18% 7% 2	16472
	Night	26% 13% 28% 25% 8% 1	25353

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	11% 19% 8% 19% 8% 6% 5% 3 4 4 13%	4661
	11th to 20th	Day	10% 19% 8% 20% 9% 5% 4 3 4 4 13%	4650
	21st to end	Day	7% 9% 7% 17% 8% 6% 5% 5% 6% 7% 22%	5124
February	1st to 10th	Day	9% 16% 5% 14% 11% 8% 5% 4 5% 5% 19%	1727
	11th to 20th	Day	12% 18% 7% 13% 7% 7% 5% 3 5% 4 19%	1954
	21st to end	Day	13% 17% 6% 11% 8% 4 6% 3 4 5% 24%	1730
March	1st to 10th	Day	16% 19% 7% 12% 5% 4 3 2 4 4 23%	4576
	11th to 20th	Day	15% 15% 5% 12% 6% 5% 5% 3 4 5% 24%	4718
	21st to end	Day	14% 16% 4 10% 5% 4 3 3 4 5% 32%	5970
April	1st to 10th	Day	21% 16% 4 10% 5% 4 4 3 4 4 25%	2400
	11th to 20th	Day	21% 13% 4 7% 4 4 3 3 4 6% 32%	2418
	21st to end	Day	22% 13% 4 8% 5% 4 4 3 5% 6% 28%	2600
May	1st to 10th	Day	24% 12% 3 8% 5% 5% 4 4 4 6% 25%	6295
	11th to 20th	Day	23% 7% 3 7% 4 5% 5% 3 5% 8% 30%	6318
	21st to end	Day	20% 10% 4 8% 6% 5% 4 4 5% 6% 29%	6949
June	1st to 10th	Day	22% 9% 3 8% 5% 5% 5% 4 6% 6% 27%	2900
	11th to 20th	Day	19% 9% 3 7% 5% 5% 5% 5% 6% 8% 30%	3000
	21st to end	Day	23% 8% 3 7% 6% 5% 5% 4 6% 6% 25%	2911
July	1st to 10th	Day	18% 8% 3 8% 5% 5% 6% 5% 6% 9% 26%	6360
	11th to 20th	Day	13% 8% 3 9% 6% 5% 6% 5% 7% 8% 30%	6360
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 5% 7% 10% 35%	6926
August	1st to 10th	Day	16% 7% 3 8% 5% 6% 7% 5% 8% 9% 27%	4563
	11th to 20th	Day	19% 8% 3 9% 5% 5% 5% 4 7% 9% 27%	4302
	21st to end	Day	19% 8% 3 8% 5% 5% 5% 4 5% 6% 31%	4350
September	1st to 10th	Day	18% 7% 3 7% 5% 5% 5% 4 6% 7% 35%	2400
	11th to 20th	Day	17% 8% 3 7% 4 4 4 4 5% 6% 37%	2285
	21st to end	Day	24% 9% 2 7% 4 5% 3 3 4 6% 32%	2200
October	1st to 10th	Day	23% 10% 3 8% 5% 4 5% 4 4 7% 28%	2102
	11th to 20th	Day	25% 15% 4 9% 5% 5% 4 2 4 6% 20%	1885
	21st to end	Day	28% 17% 4 7% 4 4 3 3 4 6% 21%	1980
November	1st to 10th	Day	20% 17% 5% 10% 6% 4 4 2 4 4 24%	1851
	11th to 20th	Day	19% 20% 6% 12% 6% 4 3 2 4 4 20%	1775
	21st to end	Day	19% 23% 8% 13% 6% 4 3 2 4 4 13%	1617
December	1st to 10th	Day	18% 18% 7% 14% 8% 7% 5% 3 3 4 13%	2350
	11th to 20th	Day	19% 16% 6% 13% 9% 4 4 2 4 5% 16%	2688
	21st to end	Day	18% 18% 6% 12% 10% 5% 5% 3 5% 4 14%	3896
January	1st to 10th	Night	12% 19% 10% 16% 7% 7% 6% 3 4 4 11%	8234
	11th to 20th	Night	10% 21% 7% 21% 10% 6% 5% 3 3 3 10%	8235
	21st to end	Night	5% 10% 6% 14% 10% 9% 8% 5% 7% 6% 19%	9057
February	1st to 10th	Night	10% 14% 5% 13% 9% 6% 5% 4 6% 6% 22%	2888
	11th to 20th	Night	11% 17% 6% 14% 9% 7% 5% 3 4 3 21%	2550
	21st to end	Night	12% 17% 5% 11% 7% 6% 5% 4 5% 5% 24%	2076
March	1st to 10th	Night	19% 15% 6% 13% 7% 4 6% 3 4 4 20%	5484
	11th to 20th	Night	14% 15% 4 11% 6% 6% 5% 4 5% 6% 22%	5392
	21st to end	Night	17% 13% 5% 9% 5% 6% 5% 3 5% 5% 27%	4962
April	1st to 10th	Night	20% 17% 4 10% 5% 4 3 3 4 5% 25%	2000
	11th to 20th	Night	21% 11% 3 8% 6% 3 4 3 4 6% 32%	1931
	21st to end	Night	23% 12% 3 7% 4 3 3 2 4 5% 33%	1800
May	1st to 10th	Night	22% 10% 3 9% 5% 5% 4 3 4 5% 30%	3688
	11th to 20th	Night	25% 8% 3 7% 4 3 5% 4 5% 7% 29%	3575
	21st to end	Night	22% 9% 3 8% 5% 4 5% 4 5% 7% 29%	3926
June	1st to 10th	Night	20% 9% 3 7% 5% 4 5% 4 5% 6% 31%	1495
	11th to 20th	Night	19% 7% 3 5% 5% 5% 4 5% 6% 8% 33%	1400
	21st to end	Night	21% 9% 4 6% 5% 5% 4 4 6% 7% 28%	1482
July	1st to 10th	Night	13% 7% 3 9% 6% 6% 6% 5% 8% 9% 27%	3600
	11th to 20th	Night	15% 8% 3 8% 6% 5% 5% 4 7% 8% 34%	3600
	21st to end	Night	13% 6% 2 5% 4 4 5% 4 6% 7% 43%	3926
August	1st to 10th	Night	13% 7% 3 7% 5% 6% 5% 5% 7% 8% 34%	2586
	11th to 20th	Night	17% 9% 3 7% 6% 5% 5% 4 6% 8% 30%	2714
	21st to end	Night	19% 7% 3 8% 6% 5% 5% 4 5% 6% 33%	3545
September	1st to 10th	Night	19% 6% 2 7% 5% 4 3 3 4 7% 41%	2000
	11th to 20th	Night	18% 6% 3 7% 4 4 4 3 5% 6% 40%	2115
	21st to end	Night	20% 8% 2 7% 5% 3 4 3 4 5% 39%	2200
October	1st to 10th	Night	19% 10% 3 6% 4 4 3 3 5% 6% 36%	2295
	11th to 20th	Night	26% 12% 3 8% 5% 3 4 3 5% 5% 25%	2515
	21st to end	Night	25% 13% 4 9% 5% 4 5% 3 4 5% 22%	2860
November	1st to 10th	Night	20% 17% 5% 10% 5% 4 4 3 4 5% 23%	2667
	11th to 20th	Night	20% 15% 5% 10% 6% 5% 5% 3 5% 4 21%	2840
	21st to end	Night	23% 20% 6% 12% 6% 4 4 3 5% 4 14%	2999
December	1st to 10th	Night	15% 16% 9% 17% 9% 5% 5% 3 3 4 13%	5060
	11th to 20th	Night	21% 16% 6% 13% 8% 6% 4 3 3 4 16%	5741
	21st to end	Night	18% 21% 7% 13% 6% 5% 4 2 4 5% 15%	7291

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	75% 4 8% 11% 3	4662
	11th to 20th	Day	76% 3 5% 10% 6%	4680
	21st to end	Day	59% 5% 6% 18% 12%	5124
February	1st to 10th	Day	67% 4 6% 14% 7% 2	1727
	11th to 20th	Day	68% 4 8% 12% 8% 1	1963
	21st to end	Day	64% 4 7% 15% 8% 2	1730
March	1st to 10th	Day	66% 4 6% 11% 11% 3	4579
	11th to 20th	Day	62% 5% 11% 12% 9% 1	4718
	21st to end	Day	56% 3 6% 16% 17% 3	5970
April	1st to 10th	Day	63% 5% 8% 12% 10% 2	2400
	11th to 20th	Day	56% 4 8% 18% 12% 3	2418
	21st to end	Day	58% 4 8% 15% 13% 2	2600
May	1st to 10th	Day	59% 5% 8% 13% 13% 1	6306
	11th to 20th	Day	52% 7% 13% 18% 8% 2	6322
	21st to end	Day	55% 6% 8% 16% 12% 4	6949
June	1st to 10th	Day	56% 6% 9% 17% 10% 2	2900
	11th to 20th	Day	50% 7% 12% 19% 10% 2	3000
	21st to end	Day	57% 8% 10% 13% 11% 1	2911
July	1st to 10th	Day	53% 6% 12% 24% 5%	6290
	11th to 20th	Day	49% 7% 17% 23% 4	6285
	21st to end	Day	43% 7% 17% 26% 7%	6728
August	1st to 10th	Day	50% 8% 18% 19% 5%	4549
	11th to 20th	Day	51% 7% 18% 19% 4	4344
	21st to end	Day	52% 7% 12% 18% 11%	4350
September	1st to 10th	Day	47% 7% 15% 22% 9% 1	2400
	11th to 20th	Day	46% 7% 17% 22% 9%	2285
	21st to end	Day	54% 6% 13% 20% 8%	2200
October	1st to 10th	Day	58% 5% 9% 23% 5%	3427
	11th to 20th	Day	65% 5% 11% 18% 2	3049
	21st to end	Day	62% 5% 16% 13% 3	3180
November	1st to 10th	Day	65% 5% 10% 14% 5% 1	1851
	11th to 20th	Day	69% 4 9% 13% 5%	1775
	21st to end	Day	76% 5% 10% 8% 2	1617
December	1st to 10th	Day	76% 5% 6% 11% 3	2350
	11th to 20th	Day	71% 3 8% 15% 4	2688
	21st to end	Day	74% 4 6% 13% 4	3896
January	1st to 10th	Night	77% 3 8% 9% 2	8234
	11th to 20th	Night	80% 3 6% 8% 3	8280
	21st to end	Night	63% 5% 8% 15% 9%	9057
February	1st to 10th	Night	62% 5% 9% 14% 9% 1	2888
	11th to 20th	Night	68% 4 8% 12% 7% 1	2552
	21st to end	Night	61% 5% 8% 17% 9%	2076
March	1st to 10th	Night	69% 4 7% 11% 9% 1	5494
	11th to 20th	Night	61% 6% 11% 12% 9% 1	5393
	21st to end	Night	58% 4 7% 20% 9% 3	4962
April	1st to 10th	Night	62% 4 9% 14% 10% 1	2000
	11th to 20th	Night	54% 5% 8% 20% 12% 1	1931
	21st to end	Night	54% 5% 9% 19% 12% 1	1800
May	1st to 10th	Night	56% 7% 8% 18% 10% 1	3694
	11th to 20th	Night	53% 7% 10% 22% 7% 1	3576
	21st to end	Night	53% 6% 11% 16% 11% 3	3927
June	1st to 10th	Night	52% 8% 9% 20% 9% 1	1495
	11th to 20th	Night	47% 7% 13% 19% 11% 3	1400
	21st to end	Night	53% 8% 12% 16% 11%	1482
July	1st to 10th	Night	50% 9% 18% 19% 4	3560
	11th to 20th	Night	46% 7% 21% 22% 3	3552
	21st to end	Night	38% 7% 19% 28% 8%	3809
August	1st to 10th	Night	46% 8% 19% 20% 7%	2576
	11th to 20th	Night	49% 8% 21% 17% 4	2738
	21st to end	Night	51% 6% 12% 22% 8%	3545
September	1st to 10th	Night	44% 7% 15% 25% 9% 1	2000
	11th to 20th	Night	44% 7% 16% 26% 6%	2115
	21st to end	Night	49% 5% 13% 25% 8%	2200
October	1st to 10th	Night	53% 5% 13% 22% 6% 1	3750
	11th to 20th	Night	58% 7% 14% 18% 3	4090
	21st to end	Night	59% 5% 15% 13% 6%	4610
November	1st to 10th	Night	64% 5% 12% 14% 5%	2667
	11th to 20th	Night	65% 6% 10% 14% 5%	2840
	21st to end	Night	74% 5% 8% 10% 2	2999
December	1st to 10th	Night	76% 5% 8% 9% 2	5060
	11th to 20th	Night	73% 3 6% 14% 3	5742
	21st to end	Night	72% 3 7% 12% 5%	7291

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% 17% 44% 12% 5%	220
	11th to 20th	Day	25% 19% 37% 13% 6%	220
	21st to end	Day	18% 17% 36% 22% 7% 1	242
February	1st to 10th	Day	18% 28% 37% 13% 2 2	245
	11th to 20th	Day	26% 25% 31% 15% 2	441
	21st to end	Day	24% 25% 33% 13% 4	446
March	1st to 10th	Day	26% 21% 32% 15% 5%	540
	11th to 20th	Day	29% 21% 28% 16% 5% 1	528
	21st to end	Day	28% 25% 27% 14% 5% 1	550
April	1st to 10th	Day	31% 18% 28% 15% 6% 1	500
	11th to 20th	Day	35% 18% 23% 15% 7% 2	492
	21st to end	Day	32% 19% 32% 11% 4 1	500
May	1st to 10th	Day	32% 17% 30% 14% 6% 2	503
	11th to 20th	Day	26% 17% 31% 20% 6% 1	527
	21st to end	Day	27% 20% 29% 17% 5% 1	573
June	1st to 10th	Day	26% 17% 30% 20% 7%	630
	11th to 20th	Day	25% 16% 28% 21% 10% 1	730
	21st to end	Day	26% 12% 30% 23% 8% 1	641
July	1st to 10th	Day	22% 13% 34% 23% 7% 2	525
	11th to 20th	Day	17% 13% 38% 23% 7% 2	524
	21st to end	Day	18% 14% 31% 26% 10% 2	576
August	1st to 10th	Day	18% 12% 29% 26% 11% 3	526
	11th to 20th	Day	19% 8% 30% 26% 12% 5%	519
	21st to end	Day	22% 17% 26% 18% 12% 5%	583
September	1st to 10th	Day	22% 15% 31% 19% 9% 5%	530
	11th to 20th	Day	18% 13% 26% 24% 13% 6%	530
	21st to end	Day	26% 15% 26% 16% 11% 5%	530
October	1st to 10th	Day	26% 18% 24% 19% 11% 2	530
	11th to 20th	Day	31% 18% 27% 13% 9% 2	467
	21st to end	Day	39% 13% 26% 16% 5%	462
November	1st to 10th	Day	35% 19% 27% 13% 4 2	425
	11th to 20th	Day	31% 18% 29% 17% 4 1	315
	21st to end	Day	33% 25% 28% 13% 2	220
December	1st to 10th	Day	31% 14% 34% 16% 5%	220
	11th to 20th	Day	30% 20% 36% 10% 4	220
	21st to end	Day	33% 19% 29% 13% 5% 2	242
January	1st to 10th	Night	25% 16% 32% 21% 6% 1	840
	11th to 20th	Night	26% 16% 30% 20% 7%	840
	21st to end	Night	17% 13% 34% 27% 9% 1	924
February	1st to 10th	Night	17% 17% 34% 23% 8% 1	840
	11th to 20th	Night	21% 16% 37% 21% 4	823
	21st to end	Night	21% 17% 29% 28% 5%	692
March	1st to 10th	Night	24% 16% 33% 22% 6%	840
	11th to 20th	Night	28% 17% 28% 21% 6%	829
	21st to end	Night	26% 15% 29% 22% 8% 1	880
April	1st to 10th	Night	30% 14% 27% 22% 6% 1	800
	11th to 20th	Night	28% 12% 29% 23% 7% 1	747
	21st to end	Night	31% 16% 29% 20% 4	600
May	1st to 10th	Night	26% 13% 30% 25% 6%	442
	11th to 20th	Night	27% 11% 25% 29% 7%	394
	21st to end	Night	27% 11% 30% 25% 6%	433
June	1st to 10th	Night	24% 8% 32% 29% 7% 1	400
	11th to 20th	Night	20% 12% 26% 33% 9%	400
	21st to end	Night	23% 7% 26% 33% 11% 1	400
July	1st to 10th	Night	17% 7% 27% 39% 10%	390
	11th to 20th	Night	16% 5% 27% 38% 15%	388
	21st to end	Night	16% 6% 24% 40% 13% 1	438
August	1st to 10th	Night	15% 5% 23% 40% 18% 1	398
	11th to 20th	Night	17% 6% 22% 36% 18% 1	495
	21st to end	Night	23% 10% 24% 27% 15% 2	852
September	1st to 10th	Night	22% 7% 24% 33% 13% 1	800
	11th to 20th	Night	21% 7% 22% 32% 16% 2	800
	21st to end	Night	25% 9% 25% 26% 14% 1	800
October	1st to 10th	Night	24% 12% 24% 29% 11% 1	800
	11th to 20th	Night	34% 12% 24% 21% 9% 1	800
	21st to end	Night	34% 12% 27% 20% 7%	880
November	1st to 10th	Night	33% 13% 26% 22% 4 2	820
	11th to 20th	Night	29% 15% 27% 20% 8% 1	840
	21st to end	Night	34% 16% 25% 21% 4	871
December	1st to 10th	Night	29% 15% 27% 21% 7% 1	950
	11th to 20th	Night	29% 16% 28% 21% 5% 1	950
	21st to end	Night	32% 15% 26% 21% 6%	957

Page generated at 2026-03-15 02:23:53. Version ac07

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