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 2024-12-06.

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	18% 12% 4 10% 6% 5% 5% 4 5% 6% 26%	101671
	Night	18% 13% 5% 10% 6% 5% 5% 3 5% 5% 25%	98042
Transparency	Day	58% 6% 11% 17% 8% 1	105121
	Night	59% 6% 12% 16% 6% 1	102682
Seeing	Day	26% 17% 30% 18% 7% 2	14928
	Night	26% 13% 28% 25% 8% 1	23673

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	14% 19% 8% 18% 9% 5% 5% 3 4 4 13%	2517
	11th to 20th	Day	13% 16% 7% 18% 9% 5% 3 3 4 4 17%	2520
	21st to end	Day	13% 13% 8% 13% 7% 6% 4 4 4 7% 20%	2772
February	1st to 10th	Day	9% 17% 5% 14% 11% 8% 5% 4 4 4 19%	1562
	11th to 20th	Day	12% 18% 7% 13% 7% 6% 6% 3 5% 4 18%	1762
	21st to end	Day	14% 18% 5% 11% 7% 4 6% 3 4 5% 23%	1570
March	1st to 10th	Day	15% 17% 5% 11% 5% 5% 4 3 3 4 28%	3116
	11th to 20th	Day	15% 18% 7% 13% 6% 4 4 3 4 5% 21%	3246
	21st to end	Day	12% 14% 4 11% 5% 4 4 3 4 6% 34%	4166
April	1st to 10th	Day	22% 16% 4 10% 5% 4 4 3 4 4 25%	2280
	11th to 20th	Day	22% 12% 4 7% 4 4 3 3 4 6% 32%	2296
	21st to end	Day	21% 13% 4 7% 5% 4 3 3 5% 6% 28%	2470
May	1st to 10th	Day	21% 10% 3 9% 5% 5% 5% 4 5% 6% 27%	4389
	11th to 20th	Day	17% 7% 3 7% 5% 5% 5% 4 6% 9% 32%	4398
	21st to end	Day	18% 8% 3 7% 6% 5% 5% 4 6% 7% 31%	4837
June	1st to 10th	Day	22% 9% 3 8% 5% 5% 5% 4 6% 6% 27%	2755
	11th to 20th	Day	19% 9% 3 7% 5% 5% 5% 5% 6% 8% 31%	2850
	21st to end	Day	24% 8% 3 7% 6% 5% 5% 4 6% 6% 25%	2766
July	1st to 10th	Day	16% 8% 3 8% 6% 5% 6% 5% 6% 8% 29%	4440
	11th to 20th	Day	15% 8% 3 9% 7% 6% 6% 5% 6% 7% 28%	4440
	21st to end	Day	13% 7% 3 7% 6% 5% 5% 5% 7% 9% 34%	4814
August	1st to 10th	Day	16% 7% 3 8% 5% 6% 7% 5% 8% 9% 26%	4423
	11th to 20th	Day	19% 8% 3 9% 5% 5% 5% 4 7% 9% 26%	4168
	21st to end	Day	19% 8% 3 8% 5% 5% 5% 4 5% 6% 32%	4217
September	1st to 10th	Day	19% 7% 3 7% 5% 5% 5% 3 5% 6% 35%	2280
	11th to 20th	Day	18% 8% 3 7% 4 4 4 4 5% 6% 37%	2171
	21st to end	Day	25% 9% 2 7% 4 5% 3 3 4 6% 31%	2090
October	1st to 10th	Day	24% 11% 3 8% 5% 4 5% 4 4 6% 27%	1997
	11th to 20th	Day	26% 15% 4 9% 5% 5% 4 2 4 6% 19%	1791
	21st to end	Day	28% 17% 4 6% 4 4 3 3 4 6% 21%	1881
November	1st to 10th	Day	20% 16% 4 10% 6% 4 4 2 4 4 25%	1761
	11th to 20th	Day	20% 19% 5% 11% 6% 4 3 2 4 4 21%	1691
	21st to end	Day	20% 22% 7% 12% 7% 4 4 3 4 4 13%	1540
December	1st to 10th	Day	22% 19% 7% 13% 7% 5% 4 2 3 4 14%	1365
	11th to 20th	Day	22% 18% 5% 9% 7% 4 4 2 3 4 20%	1668
	21st to end	Day	22% 19% 7% 12% 10% 4 4 3 4 4 12%	2662
January	1st to 10th	Night	15% 19% 8% 14% 8% 6% 5% 3 4 4 14%	4429
	11th to 20th	Night	12% 16% 5% 16% 11% 8% 5% 3 4 5% 15%	4440
	21st to end	Night	10% 15% 7% 12% 8% 8% 6% 5% 5% 6% 18%	4884
February	1st to 10th	Night	11% 15% 5% 12% 10% 6% 5% 4 6% 5% 21%	2614
	11th to 20th	Night	11% 16% 6% 15% 9% 7% 6% 3 4 3 20%	2302
	21st to end	Night	12% 17% 5% 11% 6% 6% 5% 4 5% 5% 24%	1884
March	1st to 10th	Night	20% 15% 5% 10% 5% 4 6% 3 3 4 24%	3724
	11th to 20th	Night	16% 19% 5% 12% 6% 5% 5% 3 4 5% 20%	3709
	21st to end	Night	15% 11% 5% 10% 6% 6% 5% 3 5% 5% 30%	3466
April	1st to 10th	Night	20% 17% 4 10% 5% 4 4 3 4 5% 25%	1900
	11th to 20th	Night	21% 11% 3 8% 6% 3 4 3 4 6% 32%	1833
	21st to end	Night	22% 12% 3 7% 4 3 3 2 4 5% 33%	1710
May	1st to 10th	Night	20% 11% 3 8% 5% 5% 4 3 4 6% 30%	2580
	11th to 20th	Night	21% 9% 3 7% 4 3 4 4 5% 7% 34%	2495
	21st to end	Night	21% 7% 3 8% 5% 5% 5% 4 6% 7% 30%	2738
June	1st to 10th	Night	19% 9% 3 7% 6% 4 5% 5% 5% 6% 31%	1420
	11th to 20th	Night	19% 8% 3 5% 5% 5% 4 5% 5% 8% 34%	1330
	21st to end	Night	21% 9% 4 7% 5% 5% 5% 4 6% 7% 28%	1408
July	1st to 10th	Night	15% 7% 3 10% 6% 6% 5% 5% 7% 8% 28%	2520
	11th to 20th	Night	14% 7% 3 8% 6% 5% 6% 4 7% 8% 33%	2520
	21st to end	Night	13% 5% 2 5% 4 5% 5% 4 7% 7% 44%	2739
August	1st to 10th	Night	14% 7% 3 7% 5% 6% 5% 5% 7% 8% 32%	2506
	11th to 20th	Night	17% 9% 3 7% 6% 5% 5% 4 6% 8% 29%	2629
	21st to end	Night	19% 7% 3 8% 6% 5% 5% 4 5% 6% 33%	3436
September	1st to 10th	Night	20% 6% 2 7% 5% 4 3 3 4 7% 40%	1900
	11th to 20th	Night	19% 6% 3 7% 4 4 4 3 5% 6% 39%	2009
	21st to end	Night	21% 8% 2 7% 4 3 4 3 3 5% 38%	2090
October	1st to 10th	Night	20% 10% 3 6% 5% 4 3 3 5% 6% 35%	2180
	11th to 20th	Night	27% 12% 3 8% 5% 3 4 3 5% 5% 24%	2389
	21st to end	Night	25% 13% 4 9% 5% 4 5% 3 4 4 23%	2717
November	1st to 10th	Night	20% 17% 5% 10% 5% 4 4 3 4 5% 24%	2537
	11th to 20th	Night	20% 14% 5% 10% 6% 5% 5% 4 5% 4 22%	2705
	21st to end	Night	23% 19% 6% 11% 6% 5% 4 3 5% 4 15%	2856
December	1st to 10th	Night	19% 19% 8% 12% 7% 4 4 3 3 4 15%	2932
	11th to 20th	Night	20% 17% 7% 13% 6% 5% 4 3 4 4 18%	3531
	21st to end	Night	20% 22% 7% 13% 7% 4 3 2 3 3 15%	4980

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 10% 9% 2	2518
	11th to 20th	Day	71% 4 7% 14% 4	2520
	21st to end	Day	64% 6% 6% 17% 7% 1	2772
February	1st to 10th	Day	68% 5% 6% 12% 7% 1	1562
	11th to 20th	Day	68% 4 8% 10% 8% 1	1771
	21st to end	Day	65% 4 7% 14% 7% 2	1570
March	1st to 10th	Day	60% 5% 8% 15% 10% 2	3119
	11th to 20th	Day	66% 5% 7% 14% 7%	3246
	21st to end	Day	53% 3 7% 18% 15% 3	4166
April	1st to 10th	Day	63% 5% 9% 11% 10% 2	2280
	11th to 20th	Day	55% 4 8% 18% 11% 3	2296
	21st to end	Day	58% 4 8% 15% 13% 2	2470
May	1st to 10th	Day	55% 6% 10% 14% 13% 2	4403
	11th to 20th	Day	47% 8% 14% 21% 9% 1	4402
	21st to end	Day	50% 6% 9% 18% 15% 2	4837
June	1st to 10th	Day	56% 7% 9% 17% 9% 2	2755
	11th to 20th	Day	49% 7% 12% 19% 10% 2	2850
	21st to end	Day	58% 8% 10% 13% 11%	2766
July	1st to 10th	Day	50% 7% 12% 26% 5%	4370
	11th to 20th	Day	52% 8% 16% 20% 4	4365
	21st to end	Day	46% 8% 18% 23% 6%	4661
August	1st to 10th	Day	52% 8% 17% 19% 4	4409
	11th to 20th	Day	52% 8% 18% 18% 4	4210
	21st to end	Day	52% 7% 12% 17% 12%	4217
September	1st to 10th	Day	48% 7% 14% 22% 9% 1	2280
	11th to 20th	Day	46% 7% 17% 21% 9%	2171
	21st to end	Day	55% 6% 13% 19% 7%	2090
October	1st to 10th	Day	59% 5% 9% 22% 5%	3322
	11th to 20th	Day	65% 5% 11% 17% 1	2955
	21st to end	Day	61% 5% 17% 14% 3	3081
November	1st to 10th	Day	63% 5% 11% 14% 6% 1	1761
	11th to 20th	Day	68% 4 9% 13% 5%	1691
	21st to end	Day	75% 5% 10% 8% 2	1540
December	1st to 10th	Day	75% 5% 6% 12% 3	1365
	11th to 20th	Day	70% 3 7% 15% 5%	1668
	21st to end	Day	76% 4 7% 10% 3	2662
January	1st to 10th	Night	74% 4 11% 9% 3	4429
	11th to 20th	Night	71% 4 10% 11% 3 1	4440
	21st to end	Night	64% 7% 9% 13% 7%	4884
February	1st to 10th	Night	63% 6% 9% 14% 8% 1	2614
	11th to 20th	Night	69% 4 8% 12% 7%	2304
	21st to end	Night	61% 5% 8% 16% 9% 1	1884
March	1st to 10th	Night	64% 5% 8% 14% 8% 1	3734
	11th to 20th	Night	67% 6% 8% 12% 7% 1	3710
	21st to end	Night	55% 5% 9% 19% 8% 4	3466
April	1st to 10th	Night	62% 4 9% 14% 10% 1	1900
	11th to 20th	Night	54% 5% 8% 20% 11% 2	1833
	21st to end	Night	54% 5% 9% 19% 12% 1	1710
May	1st to 10th	Night	53% 8% 10% 18% 10% 1	2586
	11th to 20th	Night	48% 7% 13% 23% 9% 1	2496
	21st to end	Night	51% 7% 10% 19% 12% 1	2739
June	1st to 10th	Night	52% 9% 10% 20% 9% 1	1420
	11th to 20th	Night	47% 7% 13% 19% 11% 3	1330
	21st to end	Night	53% 8% 12% 16% 11%	1408
July	1st to 10th	Night	50% 9% 16% 20% 4	2480
	11th to 20th	Night	47% 8% 20% 21% 4	2472
	21st to end	Night	37% 9% 21% 23% 9%	2651
August	1st to 10th	Night	47% 8% 19% 19% 7%	2496
	11th to 20th	Night	50% 9% 22% 16% 4	2653
	21st to end	Night	51% 6% 12% 23% 9%	3436
September	1st to 10th	Night	44% 7% 14% 24% 9% 1	1900
	11th to 20th	Night	45% 7% 16% 26% 6%	2009
	21st to end	Night	50% 5% 13% 25% 7%	2090
October	1st to 10th	Night	55% 5% 13% 21% 6% 1	3635
	11th to 20th	Night	59% 7% 14% 17% 3	3964
	21st to end	Night	59% 5% 16% 13% 7%	4467
November	1st to 10th	Night	63% 5% 12% 15% 5%	2537
	11th to 20th	Night	64% 6% 10% 14% 6%	2705
	21st to end	Night	73% 5% 9% 10% 2	2856
December	1st to 10th	Night	74% 5% 9% 10% 2	2932
	11th to 20th	Night	71% 4 6% 13% 5%	3532
	21st to end	Night	75% 4 8% 10% 3	4980

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	23% 18% 43% 12% 5%	180
	11th to 20th	Day	26% 18% 37% 13% 7%	180
	21st to end	Day	20% 15% 37% 21% 7% 1	198
February	1st to 10th	Day	21% 31% 35% 13% 2 1	200
	11th to 20th	Day	25% 27% 31% 14% 2	369
	21st to end	Day	26% 26% 31% 13% 4	382
March	1st to 10th	Day	24% 21% 33% 17% 5%	460
	11th to 20th	Day	26% 22% 29% 17% 6% 1	460
	21st to end	Day	27% 25% 27% 14% 5% 2	506
April	1st to 10th	Day	30% 19% 28% 16% 7% 1	460
	11th to 20th	Day	35% 18% 24% 14% 7% 2	452
	21st to end	Day	31% 20% 33% 11% 4 1	460
May	1st to 10th	Day	31% 17% 30% 14% 6% 2	463
	11th to 20th	Day	24% 17% 32% 20% 7% 1	487
	21st to end	Day	26% 22% 30% 16% 6% 1	529
June	1st to 10th	Day	26% 17% 30% 20% 7% 1	585
	11th to 20th	Day	24% 15% 28% 22% 10% 1	680
	21st to end	Day	26% 11% 30% 24% 9% 1	596
July	1st to 10th	Day	20% 13% 34% 24% 7% 2	485
	11th to 20th	Day	17% 12% 37% 24% 8% 2	484
	21st to end	Day	18% 12% 31% 26% 11% 2	532
August	1st to 10th	Day	20% 13% 29% 25% 11% 2	486
	11th to 20th	Day	20% 8% 29% 26% 12% 5%	479
	21st to end	Day	22% 17% 26% 18% 12% 5%	539
September	1st to 10th	Day	22% 15% 31% 18% 9% 5%	490
	11th to 20th	Day	19% 13% 27% 25% 12% 5%	490
	21st to end	Day	27% 14% 27% 16% 11% 5%	490
October	1st to 10th	Day	27% 18% 22% 19% 11% 2	490
	11th to 20th	Day	32% 18% 27% 12% 9% 2	433
	21st to end	Day	40% 13% 26% 16% 6%	429
November	1st to 10th	Day	33% 19% 28% 14% 4 2	395
	11th to 20th	Day	31% 19% 30% 16% 4	291
	21st to end	Day	32% 26% 28% 13% 2	200
December	1st to 10th	Day	32% 13% 32% 17% 6% 1	190
	11th to 20th	Day	30% 21% 36% 9% 3 1	180
	21st to end	Day	36% 21% 25% 12% 5% 2	198
January	1st to 10th	Night	26% 16% 32% 20% 6% 1	760
	11th to 20th	Night	26% 16% 30% 21% 7%	760
	21st to end	Night	18% 13% 33% 26% 9% 1	836
February	1st to 10th	Night	18% 17% 34% 23% 8%	760
	11th to 20th	Night	22% 16% 37% 20% 5%	743
	21st to end	Night	22% 18% 29% 26% 5%	628
March	1st to 10th	Night	23% 15% 34% 22% 6%	760
	11th to 20th	Night	27% 16% 28% 23% 7%	760
	21st to end	Night	25% 15% 30% 21% 8% 1	836
April	1st to 10th	Night	30% 13% 27% 23% 6% 1	760
	11th to 20th	Night	28% 12% 29% 22% 7% 1	709
	21st to end	Night	30% 16% 29% 21% 4	570
May	1st to 10th	Night	26% 13% 30% 25% 6%	420
	11th to 20th	Night	26% 11% 26% 29% 7%	374
	21st to end	Night	28% 12% 30% 24% 5%	411
June	1st to 10th	Night	23% 8% 31% 29% 8% 1	380
	11th to 20th	Night	20% 12% 27% 32% 9%	380
	21st to end	Night	22% 7% 26% 33% 11% 1	380
July	1st to 10th	Night	17% 6% 28% 39% 10%	370
	11th to 20th	Night	16% 5% 26% 38% 15%	368
	21st to end	Night	17% 6% 23% 40% 14% 1	416
August	1st to 10th	Night	15% 5% 24% 39% 17% 1	378
	11th to 20th	Night	17% 7% 22% 34% 19% 1	470
	21st to end	Night	22% 10% 24% 27% 15% 2	809
September	1st to 10th	Night	23% 7% 25% 33% 12% 1	760
	11th to 20th	Night	22% 7% 22% 32% 16% 2	760
	21st to end	Night	25% 10% 25% 25% 14% 1	760
October	1st to 10th	Night	25% 12% 23% 28% 11% 1	760
	11th to 20th	Night	35% 11% 24% 21% 8% 1	760
	21st to end	Night	34% 12% 28% 19% 7%	836
November	1st to 10th	Night	32% 13% 26% 23% 5% 2	780
	11th to 20th	Night	29% 16% 27% 20% 8% 1	800
	21st to end	Night	34% 16% 25% 21% 4	828
December	1st to 10th	Night	30% 15% 26% 21% 8% 1	878
	11th to 20th	Night	28% 16% 28% 21% 5% 1	850
	21st to end	Night	33% 15% 27% 20% 6%	863

Page generated at 2024-12-03 06:45:14. Version ac07

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