Baie-Comeau
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Baie-Comeau clear sky chart from 2005-11-06 to 2025-09-04.

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% 7% 32%	126502
	Night	17% 11% 4 8% 5% 4 4 3 5% 6% 32%	122379
Transparency	Day	50% 8% 13% 19% 8% 1	129924
	Night	51% 7% 12% 19% 10% 1	127045
Seeing	Day	24% 16% 31% 20% 8% 1	17091
	Night	23% 14% 29% 25% 9% 1	24841

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% 5% 13% 7% 5% 4 3 4 4 24%	3157
	11th to 20th	Day	9% 15% 7% 16% 7% 4 4 3 5% 6% 24%	3309
	21st to end	Day	5% 8% 4 11% 6% 6% 5% 4 5% 6% 40%	3960
February	1st to 10th	Day	8% 11% 4 10% 8% 6% 5% 4 5% 7% 32%	1685
	11th to 20th	Day	10% 13% 4 13% 7% 6% 4 3 5% 6% 26%	1753
	21st to end	Day	10% 13% 4 8% 5% 5% 4 4 5% 6% 34%	1622
March	1st to 10th	Day	15% 15% 4 10% 4 6% 5% 4 4 6% 27%	4512
	11th to 20th	Day	19% 18% 4 8% 5% 5% 5% 4 5% 5% 22%	4980
	21st to end	Day	19% 16% 5% 9% 4 4 3 3 4 5% 28%	5466
April	1st to 10th	Day	18% 13% 4 9% 5% 4 4 3 5% 6% 30%	2453
	11th to 20th	Day	16% 10% 3 8% 4 4 5% 4 5% 7% 35%	2572
	21st to end	Day	22% 10% 3 7% 4 3 4 4 5% 6% 32%	2600
May	1st to 10th	Day	20% 10% 3 8% 5% 5% 4 3 5% 7% 30%	5900
	11th to 20th	Day	26% 7% 2 6% 4 3 4 3 5% 6% 32%	6745
	21st to end	Day	20% 9% 3 8% 5% 4 4 4 5% 6% 32%	7451
June	1st to 10th	Day	23% 8% 3 7% 5% 5% 4 3 5% 6% 33%	3000
	11th to 20th	Day	20% 6% 3 6% 5% 4 4 4 6% 8% 34%	3000
	21st to end	Day	24% 8% 3 7% 4 5% 4 5% 6% 7% 28%	3000
July	1st to 10th	Day	16% 7% 2 7% 5% 6% 5% 4 7% 8% 32%	6820
	11th to 20th	Day	16% 7% 3 7% 5% 6% 5% 5% 7% 8% 31%	6820
	21st to end	Day	12% 5% 2 6% 4 5% 5% 4 7% 9% 42%	7123
August	1st to 10th	Day	14% 5% 2 7% 5% 6% 7% 5% 8% 9% 32%	4413
	11th to 20th	Day	19% 7% 2 7% 5% 6% 6% 5% 7% 8% 29%	4175
	21st to end	Day	14% 5% 2 7% 4 5% 6% 5% 7% 8% 37%	4675
September	1st to 10th	Day	17% 8% 2 6% 5% 5% 5% 3 5% 7% 37%	2352
	11th to 20th	Day	22% 7% 2 5% 4 4 3 3 4 6% 40%	2090
	21st to end	Day	20% 7% 2 7% 5% 4 4 3 4 6% 38%	2090
October	1st to 10th	Day	20% 6% 2 7% 5% 5% 5% 3 5% 7% 36%	1976
	11th to 20th	Day	26% 7% 3 7% 5% 5% 5% 4 5% 6% 27%	1829
	21st to end	Day	26% 11% 3 7% 6% 4 4 2 5% 6% 27%	1881
November	1st to 10th	Day	20% 10% 3 9% 6% 5% 5% 3 4 6% 29%	1661
	11th to 20th	Day	23% 13% 4 8% 4 5% 4 3 5% 6% 26%	1600
	21st to end	Day	22% 14% 5% 7% 5% 4 4 3 4 5% 25%	1458
December	1st to 10th	Day	14% 16% 5% 10% 5% 5% 3 3 4 5% 30%	2280
	11th to 20th	Day	19% 12% 5% 9% 5% 3 4 3 5% 6% 30%	2618
	21st to end	Day	15% 13% 5% 10% 4 3 2 2 4 5% 36%	3476
January	1st to 10th	Night	15% 21% 7% 12% 6% 4 4 3 3 4 22%	6808
	11th to 20th	Night	10% 15% 6% 13% 6% 6% 5% 4 5% 6% 25%	6572
	21st to end	Night	4 9% 4 9% 5% 5% 5% 5% 6% 6% 42%	6996
February	1st to 10th	Night	8% 12% 5% 10% 7% 5% 4 3 5% 6% 34%	2715
	11th to 20th	Night	12% 15% 5% 10% 6% 4 4 4 5% 6% 28%	2533
	21st to end	Night	11% 14% 4 9% 6% 6% 4 4 5% 5% 31%	2005
March	1st to 10th	Night	18% 13% 4 7% 5% 5% 5% 3 5% 6% 30%	5327
	11th to 20th	Night	20% 17% 5% 10% 5% 4 4 3 4 6% 23%	4979
	21st to end	Night	19% 17% 4 6% 4 3 5% 3 4 5% 30%	5466
April	1st to 10th	Night	23% 11% 3 6% 5% 3 4 3 4 5% 32%	1943
	11th to 20th	Night	20% 10% 3 5% 5% 4 4 3 5% 7% 36%	1778
	21st to end	Night	24% 11% 2 6% 3 3 3 2 4 6% 36%	1800
May	1st to 10th	Night	22% 7% 3 8% 4 4 4 3 5% 6% 34%	4038
	11th to 20th	Night	25% 9% 3 6% 4 4 4 3 4 5% 33%	3212
	21st to end	Night	20% 7% 2 8% 6% 5% 5% 4 5% 7% 31%	3446
June	1st to 10th	Night	23% 8% 2 5% 5% 4 4 4 5% 8% 33%	1400
	11th to 20th	Night	19% 6% 3 8% 5% 4 4 4 6% 8% 33%	1400
	21st to end	Night	25% 7% 3 7% 5% 4 4 4 5% 6% 30%	1400
July	1st to 10th	Night	14% 6% 2 7% 5% 5% 6% 5% 7% 8% 36%	3160
	11th to 20th	Night	15% 6% 3 6% 4 5% 5% 4 6% 9% 35%	3160
	21st to end	Night	11% 5% 2 6% 4 4 4 4 6% 8% 46%	3722
August	1st to 10th	Night	17% 5% 3 7% 5% 5% 5% 5% 6% 8% 35%	2703
	11th to 20th	Night	18% 7% 3 7% 5% 4 5% 4 7% 9% 32%	2872
	21st to end	Night	15% 6% 2 6% 4 5% 5% 4 6% 6% 41%	3223
September	1st to 10th	Night	17% 8% 3 6% 4 5% 4 4 5% 6% 39%	1894
	11th to 20th	Night	21% 6% 2 5% 5% 4 4 3 5% 6% 39%	2090
	21st to end	Night	20% 6% 2 5% 4 3 3 3 5% 6% 43%	2090
October	1st to 10th	Night	20% 7% 2 6% 4 4 4 3 5% 6% 39%	2203
	11th to 20th	Night	24% 8% 2 6% 4 5% 4 4 5% 6% 32%	2347
	21st to end	Night	25% 9% 3 6% 4 4 3 4 5% 5% 32%	2717
November	1st to 10th	Night	21% 11% 4 7% 4 4 4 3 4 6% 31%	2637
	11th to 20th	Night	20% 12% 4 7% 5% 4 4 4 4 5% 30%	2800
	21st to end	Night	20% 17% 5% 8% 5% 3 4 3 4 5% 25%	2940
December	1st to 10th	Night	14% 14% 5% 10% 5% 4 4 3 5% 5% 31%	4910
	11th to 20th	Night	20% 13% 4 9% 4 4 3 2 4 5% 30%	5591
	21st to end	Night	16% 13% 5% 10% 4 4 4 3 4 6% 31%	7502

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	63% 6% 12% 14% 4	3158
	11th to 20th	Day	56% 8% 13% 16% 5% 1	3336
	21st to end	Day	42% 7% 11% 22% 17% 1	3960
February	1st to 10th	Day	50% 7% 11% 20% 10% 2	1685
	11th to 20th	Day	58% 6% 11% 15% 9%	1761
	21st to end	Day	49% 5% 10% 24% 11% 1	1622
March	1st to 10th	Day	55% 9% 9% 15% 10% 1	4515
	11th to 20th	Day	62% 6% 9% 13% 8% 1	4980
	21st to end	Day	58% 5% 7% 17% 11% 2	5466
April	1st to 10th	Day	54% 6% 10% 15% 14% 1	2453
	11th to 20th	Day	47% 7% 13% 22% 11% 1	2572
	21st to end	Day	52% 6% 11% 18% 12% 2	2600
May	1st to 10th	Day	51% 10% 13% 19% 6% 2	5911
	11th to 20th	Day	51% 8% 14% 17% 9% 2	6749
	21st to end	Day	49% 8% 13% 20% 10% 1	7451
June	1st to 10th	Day	51% 7% 11% 19% 9% 3	3000
	11th to 20th	Day	47% 8% 14% 17% 12% 2	3000
	21st to end	Day	53% 9% 13% 15% 9% 1	3000
July	1st to 10th	Day	46% 9% 13% 25% 6%	6745
	11th to 20th	Day	47% 10% 17% 20% 6%	6739
	21st to end	Day	36% 9% 17% 27% 10%	6920
August	1st to 10th	Day	44% 12% 19% 19% 6%	4399
	11th to 20th	Day	50% 11% 21% 15% 4	4214
	21st to end	Day	42% 11% 18% 20% 10%	4675
September	1st to 10th	Day	45% 10% 16% 19% 10%	2352
	11th to 20th	Day	45% 7% 15% 24% 8%	2090
	21st to end	Day	47% 8% 13% 23% 9%	2090
October	1st to 10th	Day	53% 8% 15% 18% 6% 1	3288
	11th to 20th	Day	52% 9% 11% 26% 3	3019
	21st to end	Day	49% 6% 16% 20% 9%	3081
November	1st to 10th	Day	55% 7% 16% 15% 7%	1661
	11th to 20th	Day	59% 7% 13% 17% 3	1600
	21st to end	Day	61% 6% 12% 15% 5% 1	1458
December	1st to 10th	Day	56% 7% 12% 16% 8%	2280
	11th to 20th	Day	55% 6% 11% 20% 7%	2618
	21st to end	Day	51% 5% 10% 22% 8% 3	3476
January	1st to 10th	Night	66% 6% 8% 13% 6% 1	6808
	11th to 20th	Night	57% 9% 13% 17% 4 1	6619
	21st to end	Night	38% 8% 14% 22% 18%	6996
February	1st to 10th	Night	50% 5% 10% 19% 14% 2	2715
	11th to 20th	Night	55% 7% 11% 18% 9% 1	2536
	21st to end	Night	54% 7% 8% 20% 10% 2	2005
March	1st to 10th	Night	55% 7% 9% 15% 14% 1	5337
	11th to 20th	Night	62% 6% 9% 14% 8% 1	4980
	21st to end	Night	55% 6% 7% 14% 16% 2	5466
April	1st to 10th	Night	55% 6% 9% 14% 14% 3	1943
	11th to 20th	Night	47% 7% 9% 19% 16% 2	1778
	21st to end	Night	51% 4 10% 18% 15% 3	1800
May	1st to 10th	Night	48% 9% 11% 15% 14% 2	4044
	11th to 20th	Night	53% 6% 10% 19% 10% 1	3213
	21st to end	Night	49% 9% 12% 17% 11% 2	3447
June	1st to 10th	Night	48% 7% 13% 19% 12% 2	1400
	11th to 20th	Night	47% 8% 13% 17% 12% 2	1400
	21st to end	Night	54% 7% 9% 17% 11% 1	1400
July	1st to 10th	Night	42% 9% 14% 25% 10%	3125
	11th to 20th	Night	43% 8% 19% 24% 6%	3118
	21st to end	Night	35% 7% 21% 23% 14%	3611
August	1st to 10th	Night	44% 9% 18% 23% 7%	2693
	11th to 20th	Night	46% 11% 23% 15% 5%	2899
	21st to end	Night	39% 9% 14% 26% 11%	3223
September	1st to 10th	Night	44% 8% 14% 24% 9%	1894
	11th to 20th	Night	45% 8% 16% 21% 9% 1	2090
	21st to end	Night	42% 6% 14% 25% 12%	2090
October	1st to 10th	Night	51% 5% 11% 25% 6% 1	3671
	11th to 20th	Night	48% 7% 13% 25% 6%	3896
	21st to end	Night	51% 8% 13% 22% 7%	4467
November	1st to 10th	Night	55% 8% 12% 16% 8% 1	2637
	11th to 20th	Night	55% 8% 14% 18% 5%	2800
	21st to end	Night	62% 7% 10% 13% 8% 1	2940
December	1st to 10th	Night	54% 7% 14% 18% 7%	4910
	11th to 20th	Night	56% 5% 10% 20% 8%	5592
	21st to end	Night	54% 7% 11% 19% 7% 2	7502

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	24% 17% 33% 19% 8%	200
	11th to 20th	Day	20% 24% 26% 20% 10% 2	200
	21st to end	Day	18% 20% 31% 23% 6% 2	220
February	1st to 10th	Day	17% 17% 38% 19% 6% 2	285
	11th to 20th	Day	14% 21% 40% 19% 5% 1	396
	21st to end	Day	22% 20% 39% 12% 5% 1	401
March	1st to 10th	Day	24% 18% 34% 18% 6%	500
	11th to 20th	Day	24% 20% 28% 20% 8% 1	500
	21st to end	Day	26% 22% 31% 14% 5% 2	550
April	1st to 10th	Day	27% 24% 28% 16% 4	500
	11th to 20th	Day	23% 18% 34% 19% 4 1	492
	21st to end	Day	27% 18% 32% 15% 6% 1	500
May	1st to 10th	Day	28% 17% 28% 20% 6% 1	504
	11th to 20th	Day	25% 14% 29% 22% 9% 1	724
	21st to end	Day	26% 20% 28% 18% 7% 1	790
June	1st to 10th	Day	28% 13% 31% 21% 7% 1	730
	11th to 20th	Day	23% 15% 29% 20% 11% 2	730
	21st to end	Day	26% 12% 31% 22% 8% 1	730
July	1st to 10th	Day	21% 13% 32% 25% 9% 1	720
	11th to 20th	Day	19% 10% 30% 29% 11% 1	718
	21st to end	Day	18% 12% 32% 27% 9% 2	669
August	1st to 10th	Day	18% 12% 30% 27% 10% 2	526
	11th to 20th	Day	19% 11% 31% 27% 10% 2	519
	21st to end	Day	19% 12% 32% 22% 11% 3	583
September	1st to 10th	Day	22% 14% 33% 20% 8% 3	502
	11th to 20th	Day	26% 15% 26% 23% 6% 3	490
	21st to end	Day	20% 16% 32% 19% 8% 3	490
October	1st to 10th	Day	22% 18% 29% 20% 10% 2	430
	11th to 20th	Day	30% 16% 29% 14% 10% 1	390
	21st to end	Day	34% 15% 24% 17% 8% 1	429
November	1st to 10th	Day	30% 17% 34% 14% 5% 1	395
	11th to 20th	Day	30% 15% 27% 22% 6% 1	400
	21st to end	Day	28% 22% 29% 17% 3	258
December	1st to 10th	Day	26% 17% 28% 18% 10% 3	200
	11th to 20th	Day	26% 25% 31% 14% 5% 1	200
	21st to end	Day	24% 19% 34% 19% 4 1	220
January	1st to 10th	Night	24% 14% 36% 21% 4	900
	11th to 20th	Night	20% 18% 32% 23% 7%	857
	21st to end	Night	13% 17% 35% 28% 6%	880
February	1st to 10th	Night	13% 19% 38% 21% 8% 1	800
	11th to 20th	Night	21% 16% 35% 21% 7%	783
	21st to end	Night	18% 14% 37% 22% 8% 1	660
March	1st to 10th	Night	19% 16% 34% 24% 6% 1	800
	11th to 20th	Night	19% 21% 31% 23% 7%	800
	21st to end	Night	23% 18% 29% 22% 8%	880
April	1st to 10th	Night	29% 16% 27% 22% 5%	738
	11th to 20th	Night	25% 14% 29% 22% 9% 1	594
	21st to end	Night	30% 13% 27% 22% 8% 1	600
May	1st to 10th	Night	26% 13% 25% 28% 8% 1	600
	11th to 20th	Night	24% 8% 28% 30% 10%	429
	21st to end	Night	24% 11% 28% 28% 10%	433
June	1st to 10th	Night	25% 6% 28% 31% 10%	400
	11th to 20th	Night	23% 6% 23% 33% 15% 2	400
	21st to end	Night	26% 6% 24% 33% 11% 1	400
July	1st to 10th	Night	19% 5% 26% 37% 12% 1	390
	11th to 20th	Night	17% 5% 21% 42% 13% 2	388
	21st to end	Night	18% 7% 19% 36% 18% 1	438
August	1st to 10th	Night	19% 5% 17% 38% 19% 2	463
	11th to 20th	Night	20% 6% 22% 35% 16% 1	592
	21st to end	Night	18% 6% 23% 35% 17% 1	660
September	1st to 10th	Night	21% 9% 26% 30% 13% 1	660
	11th to 20th	Night	23% 8% 27% 26% 14% 1	760
	21st to end	Night	23% 10% 26% 28% 13% 1	760
October	1st to 10th	Night	22% 15% 25% 27% 10% 1	760
	11th to 20th	Night	26% 11% 27% 25% 10% 1	760
	21st to end	Night	31% 13% 27% 21% 7% 1	836
November	1st to 10th	Night	28% 17% 28% 21% 5%	830
	11th to 20th	Night	26% 19% 29% 20% 5% 1	900
	21st to end	Night	29% 18% 30% 18% 4	900
December	1st to 10th	Night	27% 14% 29% 23% 6% 1	900
	11th to 20th	Night	26% 22% 29% 16% 6%	900
	21st to end	Night	26% 17% 27% 23% 5% 2	990

Page generated at 2025-09-01 01:51:09. Version ac07

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