Saint-Lin-Laurentides
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint-Lin-Laurentides 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	16% 9% 3 8% 5% 5% 5% 4 5% 7% 33%	131254
	Night	16% 11% 4 9% 5% 4 4 3 5% 6% 32%	130268
Transparency	Day	48% 8% 13% 20% 10% 1	134699
	Night	51% 7% 12% 19% 10% 1	134910
Seeing	Day	20% 14% 31% 24% 10% 2	16157
	Night	21% 10% 32% 28% 9% 1	25252

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	13% 17% 6% 12% 4 4 4 4 5% 5% 26%	4661
	11th to 20th	Day	10% 17% 7% 12% 6% 5% 5% 3 4 5% 25%	4650
	21st to end	Day	7% 13% 6% 13% 8% 6% 5% 4 6% 6% 26%	5124
February	1st to 10th	Day	12% 16% 4 9% 7% 5% 5% 4 4 5% 29%	1834
	11th to 20th	Day	11% 13% 6% 11% 6% 5% 5% 4 5% 5% 29%	1943
	21st to end	Day	16% 16% 3 11% 6% 4 5% 3 4 5% 28%	1730
March	1st to 10th	Day	19% 13% 4 10% 7% 5% 5% 3 4 5% 26%	4576
	11th to 20th	Day	11% 13% 4 10% 5% 5% 4 3 5% 7% 34%	4767
	21st to end	Day	18% 10% 4 9% 5% 5% 4 3 4 5% 34%	5966
April	1st to 10th	Day	21% 11% 3 8% 5% 4 5% 3 4 4 33%	2400
	11th to 20th	Day	21% 8% 2 6% 5% 4 4 3 4 5% 37%	2374
	21st to end	Day	21% 9% 3 7% 5% 4 4 4 4 5% 33%	2567
May	1st to 10th	Day	26% 9% 3 8% 5% 5% 4 3 5% 6% 24%	6294
	11th to 20th	Day	20% 8% 3 8% 5% 5% 4 3 6% 7% 31%	6318
	21st to end	Day	22% 8% 2 6% 4 5% 5% 4 6% 7% 31%	6949
June	1st to 10th	Day	20% 7% 3 7% 5% 6% 4 4 6% 7% 30%	2800
	11th to 20th	Day	14% 7% 2 7% 5% 4 5% 5% 7% 8% 37%	2800
	21st to end	Day	19% 7% 3 8% 6% 5% 5% 4 6% 7% 30%	2800
July	1st to 10th	Day	14% 5% 3 8% 6% 6% 6% 5% 6% 8% 33%	6360
	11th to 20th	Day	11% 6% 2 5% 4 5% 6% 5% 7% 9% 39%	6360
	21st to end	Day	9% 5% 2 5% 4 4 4 4 6% 10% 46%	6926
August	1st to 10th	Day	13% 5% 2 7% 5% 6% 6% 5% 7% 9% 33%	4563
	11th to 20th	Day	14% 6% 3 8% 5% 4 4 4 7% 8% 37%	4155
	21st to end	Day	15% 5% 2 6% 4 5% 4 4 7% 8% 40%	4312
September	1st to 10th	Day	12% 5% 2 5% 4 4 5% 4 6% 8% 44%	2400
	11th to 20th	Day	12% 5% 2 5% 3 3 3 3 5% 7% 51%	2318
	21st to end	Day	17% 6% 2 6% 5% 4 4 3 5% 6% 43%	2200
October	1st to 10th	Day	18% 7% 3 6% 3 5% 3 3 6% 7% 39%	2060
	11th to 20th	Day	18% 8% 4 7% 6% 5% 5% 4 5% 7% 32%	1952
	21st to end	Day	22% 10% 4 7% 4 5% 4 3 5% 5% 32%	1980
November	1st to 10th	Day	14% 10% 3 7% 4 4 5% 4 5% 6% 35%	1851
	11th to 20th	Day	17% 11% 4 8% 4 4 5% 4 5% 6% 33%	1790
	21st to end	Day	21% 12% 3 7% 6% 5% 4 4 4 8% 26%	1680
December	1st to 10th	Day	19% 16% 6% 12% 6% 5% 5% 3 4 4 20%	2680
	11th to 20th	Day	18% 15% 3 8% 5% 4 5% 3 5% 5% 28%	3066
	21st to end	Day	23% 14% 4 9% 5% 4 4 3 4 5% 25%	4048
January	1st to 10th	Night	12% 17% 7% 14% 5% 4 4 3 4 4 25%	8234
	11th to 20th	Night	10% 16% 7% 16% 8% 5% 5% 3 5% 5% 21%	8235
	21st to end	Night	9% 12% 5% 13% 8% 6% 5% 4 5% 6% 28%	9057
February	1st to 10th	Night	12% 14% 5% 11% 7% 5% 5% 4 6% 5% 27%	2782
	11th to 20th	Night	13% 11% 5% 10% 6% 5% 5% 4 5% 5% 32%	2562
	21st to end	Night	14% 13% 4 9% 5% 5% 4 3 4 6% 32%	2076
March	1st to 10th	Night	21% 13% 4 8% 5% 4 4 3 4 4 30%	5484
	11th to 20th	Night	13% 13% 4 8% 5% 4 5% 4 6% 6% 32%	5344
	21st to end	Night	16% 11% 4 9% 5% 5% 4 4 5% 4 33%	4965
April	1st to 10th	Night	23% 10% 3 7% 5% 4 4 3 4 7% 31%	2000
	11th to 20th	Night	21% 8% 3 6% 4 4 5% 3 5% 6% 36%	1975
	21st to end	Night	21% 10% 3 6% 3 3 4 3 5% 5% 37%	1832
May	1st to 10th	Night	26% 10% 3 9% 5% 5% 4 4 4 6% 26%	3689
	11th to 20th	Night	21% 8% 3 7% 5% 4 4 4 5% 7% 32%	3575
	21st to end	Night	20% 9% 4 8% 5% 4 4 4 5% 7% 31%	3926
June	1st to 10th	Night	20% 7% 3 6% 6% 4 3 3 5% 8% 34%	1600
	11th to 20th	Night	16% 7% 2 7% 4 4 4 4 7% 7% 39%	1600
	21st to end	Night	20% 6% 3 6% 4 4 5% 4 6% 8% 35%	1600
July	1st to 10th	Night	12% 6% 3 7% 5% 6% 5% 6% 7% 9% 34%	3600
	11th to 20th	Night	13% 6% 3 6% 4 4 5% 4 6% 7% 44%	3600
	21st to end	Night	9% 5% 2 6% 4 4 5% 4 7% 8% 47%	3926
August	1st to 10th	Night	13% 6% 3 7% 5% 4 5% 5% 6% 7% 39%	2586
	11th to 20th	Night	15% 7% 3 7% 4 4 5% 3 6% 6% 41%	2857
	21st to end	Night	17% 6% 3 7% 4 4 4 3 6% 7% 40%	3586
September	1st to 10th	Night	10% 4 2 6% 4 5% 5% 3 5% 7% 47%	2000
	11th to 20th	Night	13% 5% 2 5% 3 3 3 3 5% 7% 52%	2081
	21st to end	Night	16% 6% 1 6% 4 3 4 3 4 6% 47%	2200
October	1st to 10th	Night	18% 6% 2 7% 4 5% 4 3 4 5% 43%	2337
	11th to 20th	Night	18% 8% 3 7% 4 4 4 3 5% 6% 38%	2447
	21st to end	Night	21% 9% 2 7% 5% 5% 4 3 4 6% 33%	2860
November	1st to 10th	Night	18% 9% 3 7% 5% 5% 4 3 5% 6% 34%	2667
	11th to 20th	Night	18% 10% 3 8% 5% 4 4 4 5% 5% 35%	2827
	21st to end	Night	21% 13% 3 8% 5% 4 4 3 4 5% 30%	2940
December	1st to 10th	Night	17% 14% 5% 10% 7% 6% 5% 4 5% 5% 21%	4720
	11th to 20th	Night	23% 13% 4 9% 5% 4 4 3 4 5% 29%	5348
	21st to end	Night	23% 16% 4 9% 4 3 3 2 4 4 27%	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	57% 8% 13% 18% 5% 1	4662
	11th to 20th	Day	58% 8% 10% 14% 8% 2	4680
	21st to end	Day	55% 8% 10% 14% 12% 1	5124
February	1st to 10th	Day	56% 6% 9% 18% 8% 2	1834
	11th to 20th	Day	55% 8% 11% 15% 10% 1	1952
	21st to end	Day	58% 5% 10% 15% 10% 2	1730
March	1st to 10th	Day	59% 7% 9% 12% 10% 4	4579
	11th to 20th	Day	48% 8% 19% 13% 10% 3	4767
	21st to end	Day	51% 6% 9% 15% 17% 2	5966
April	1st to 10th	Day	54% 5% 9% 18% 12% 2	2400
	11th to 20th	Day	48% 7% 9% 22% 14% 2	2374
	21st to end	Day	51% 7% 9% 17% 12% 3	2567
May	1st to 10th	Day	58% 8% 9% 17% 7% 1	6305
	11th to 20th	Day	50% 8% 16% 16% 8% 2	6322
	21st to end	Day	49% 8% 13% 17% 12% 1	6949
June	1st to 10th	Day	50% 8% 12% 17% 11% 2	2800
	11th to 20th	Day	42% 9% 13% 21% 12% 3	2800
	21st to end	Day	52% 8% 12% 17% 9% 1	2800
July	1st to 10th	Day	45% 8% 15% 23% 8%	6290
	11th to 20th	Day	36% 10% 16% 28% 10%	6285
	21st to end	Day	32% 8% 17% 34% 10%	6728
August	1st to 10th	Day	43% 10% 19% 20% 8%	4549
	11th to 20th	Day	41% 10% 19% 24% 6%	4197
	21st to end	Day	39% 8% 18% 21% 13% 1	4312
September	1st to 10th	Day	34% 10% 16% 28% 12%	2400
	11th to 20th	Day	32% 8% 15% 31% 13% 1	2318
	21st to end	Day	42% 7% 14% 25% 12%	2200
October	1st to 10th	Day	42% 7% 15% 25% 10%	3359
	11th to 20th	Day	42% 7% 17% 27% 7%	3155
	21st to end	Day	42% 6% 21% 21% 10% 1	3180
November	1st to 10th	Day	47% 8% 15% 20% 9% 1	1851
	11th to 20th	Day	50% 7% 15% 17% 10% 1	1790
	21st to end	Day	57% 8% 15% 14% 6% 1	1680
December	1st to 10th	Day	67% 6% 9% 15% 4	2680
	11th to 20th	Day	55% 7% 11% 17% 10%	3066
	21st to end	Day	59% 8% 11% 14% 8%	4048
January	1st to 10th	Night	61% 7% 11% 14% 6% 1	8234
	11th to 20th	Night	62% 9% 10% 13% 6% 1	8280
	21st to end	Night	56% 7% 10% 13% 14% 1	9057
February	1st to 10th	Night	57% 7% 10% 16% 9% 1	2782
	11th to 20th	Night	52% 7% 11% 19% 10% 1	2564
	21st to end	Night	53% 6% 9% 18% 12% 1	2076
March	1st to 10th	Night	57% 6% 9% 13% 11% 4	5494
	11th to 20th	Night	49% 9% 14% 15% 12% 2	5345
	21st to end	Night	51% 7% 8% 20% 13% 2	4965
April	1st to 10th	Night	52% 6% 9% 18% 14% 2	2000
	11th to 20th	Night	48% 6% 9% 20% 14% 2	1975
	21st to end	Night	48% 6% 9% 19% 14% 3	1832
May	1st to 10th	Night	57% 8% 10% 16% 6% 2	3695
	11th to 20th	Night	49% 9% 13% 17% 10% 2	3576
	21st to end	Night	51% 8% 11% 16% 13% 1	3927
June	1st to 10th	Night	48% 7% 12% 18% 14% 1	1600
	11th to 20th	Night	43% 8% 12% 20% 13% 3	1600
	21st to end	Night	47% 9% 11% 18% 14% 1	1600
July	1st to 10th	Night	42% 9% 19% 21% 9%	3560
	11th to 20th	Night	37% 9% 18% 29% 8%	3552
	21st to end	Night	33% 7% 18% 29% 12%	3809
August	1st to 10th	Night	42% 9% 14% 27% 9%	2576
	11th to 20th	Night	41% 8% 18% 25% 8%	2881
	21st to end	Night	42% 8% 15% 22% 13% 1	3586
September	1st to 10th	Night	34% 10% 15% 26% 15% 1	2000
	11th to 20th	Night	33% 6% 15% 33% 12% 1	2081
	21st to end	Night	39% 7% 12% 28% 14%	2200
October	1st to 10th	Night	42% 8% 14% 24% 12% 1	3818
	11th to 20th	Night	41% 6% 12% 30% 11%	3983
	21st to end	Night	43% 7% 18% 18% 12% 2	4610
November	1st to 10th	Night	49% 7% 13% 21% 8% 1	2667
	11th to 20th	Night	50% 6% 13% 19% 10% 1	2827
	21st to end	Night	58% 6% 11% 17% 7% 1	2940
December	1st to 10th	Night	63% 7% 12% 14% 4	4720
	11th to 20th	Night	58% 6% 9% 16% 11% 1	5348
	21st to end	Night	61% 5% 8% 14% 12%	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	20% 16% 34% 24% 5%	220
	11th to 20th	Day	22% 21% 35% 17% 4 1	220
	21st to end	Day	16% 18% 33% 26% 5% 2	242
February	1st to 10th	Day	24% 22% 34% 18% 2	302
	11th to 20th	Day	18% 17% 40% 21% 3	430
	21st to end	Day	26% 15% 36% 20% 3	446
March	1st to 10th	Day	24% 16% 34% 20% 5%	540
	11th to 20th	Day	21% 20% 34% 21% 3 1	528
	21st to end	Day	26% 17% 31% 16% 8% 1	550
April	1st to 10th	Day	24% 20% 30% 19% 7% 1	500
	11th to 20th	Day	28% 21% 24% 17% 9% 1	492
	21st to end	Day	27% 16% 33% 17% 6% 1	500
May	1st to 10th	Day	24% 15% 33% 21% 6% 1	503
	11th to 20th	Day	20% 14% 32% 23% 10% 2	527
	21st to end	Day	20% 15% 33% 23% 7% 2	573
June	1st to 10th	Day	22% 11% 34% 23% 9% 1	530
	11th to 20th	Day	16% 14% 30% 28% 11% 1	530
	21st to end	Day	22% 12% 28% 26% 10% 2	530
July	1st to 10th	Day	13% 8% 32% 31% 13% 4	525
	11th to 20th	Day	12% 9% 31% 32% 14% 2	524
	21st to end	Day	11% 7% 31% 32% 15% 3	576
August	1st to 10th	Day	13% 8% 23% 34% 19% 3	526
	11th to 20th	Day	11% 6% 24% 33% 18% 8%	519
	21st to end	Day	15% 9% 27% 25% 17% 8%	583
September	1st to 10th	Day	14% 7% 29% 28% 15% 7%	530
	11th to 20th	Day	11% 9% 22% 28% 21% 9%	530
	21st to end	Day	19% 10% 27% 24% 15% 5%	530
October	1st to 10th	Day	21% 11% 28% 24% 12% 3	530
	11th to 20th	Day	19% 17% 32% 21% 10% 1	502
	21st to end	Day	26% 15% 30% 23% 6%	462
November	1st to 10th	Day	25% 15% 31% 22% 7%	425
	11th to 20th	Day	22% 16% 35% 18% 8%	330
	21st to end	Day	29% 18% 32% 14% 6%	220
December	1st to 10th	Day	25% 18% 24% 25% 7% 1	220
	11th to 20th	Day	22% 18% 40% 19% 1 1	220
	21st to end	Day	28% 17% 31% 16% 7% 2	242
January	1st to 10th	Night	23% 13% 35% 25% 4	840
	11th to 20th	Night	22% 13% 35% 24% 6%	840
	21st to end	Night	16% 11% 38% 28% 7% 1	924
February	1st to 10th	Night	18% 11% 39% 26% 5% 1	840
	11th to 20th	Night	18% 13% 42% 22% 5%	823
	21st to end	Night	20% 12% 38% 27% 4	692
March	1st to 10th	Night	24% 15% 33% 24% 4	840
	11th to 20th	Night	23% 14% 33% 23% 6%	829
	21st to end	Night	21% 10% 38% 25% 6%	880
April	1st to 10th	Night	28% 11% 31% 26% 4	800
	11th to 20th	Night	25% 12% 32% 26% 5% 1	791
	21st to end	Night	27% 10% 33% 23% 6%	632
May	1st to 10th	Night	24% 10% 32% 27% 6% 1	443
	11th to 20th	Night	22% 9% 30% 31% 8%	394
	21st to end	Night	21% 7% 38% 27% 8%	433
June	1st to 10th	Night	23% 6% 31% 32% 8%	400
	11th to 20th	Night	18% 8% 29% 33% 12%	400
	21st to end	Night	21% 7% 27% 32% 13%	400
July	1st to 10th	Night	9% 7% 32% 37% 14% 1	390
	11th to 20th	Night	13% 4 24% 45% 14%	388
	21st to end	Night	12% 3 26% 44% 14% 1	438
August	1st to 10th	Night	13% 4 16% 47% 19%	398
	11th to 20th	Night	14% 4 23% 34% 22% 2	573
	21st to end	Night	15% 6% 24% 35% 18% 2	880
September	1st to 10th	Night	14% 5% 26% 39% 15% 1	800
	11th to 20th	Night	14% 5% 22% 35% 23% 2	800
	21st to end	Night	19% 5% 29% 32% 14% 2	800
October	1st to 10th	Night	21% 6% 29% 32% 11% 1	800
	11th to 20th	Night	22% 8% 31% 29% 9% 1	800
	21st to end	Night	26% 9% 33% 25% 6%	880
November	1st to 10th	Night	22% 12% 33% 26% 7%	820
	11th to 20th	Night	24% 10% 34% 22% 9% 1	840
	21st to end	Night	27% 13% 33% 20% 6% 1	840
December	1st to 10th	Night	27% 11% 32% 23% 6%	840
	11th to 20th	Night	27% 13% 34% 22% 4 1	840
	21st to end	Night	31% 12% 31% 20% 5%	924

Page generated at 2026-03-15 02:23:57. Version ac07

Copyright © 2026 Attilla Danko.