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 2024-11-04.

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%	101796
	Night	17% 11% 4 8% 5% 4 4 4 5% 6% 33%	97312
Transparency	Day	50% 9% 14% 19% 8% 1	105239
	Night	51% 8% 12% 19% 9% 1	101959
Seeing	Day	23% 16% 31% 21% 8% 2	15985
	Night	23% 14% 29% 25% 9% 1	23792

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% 13% 5% 13% 6% 4 5% 3 4 5% 29%	2207
	11th to 20th	Day	11% 17% 6% 12% 6% 5% 4 4 5% 6% 23%	2334
	21st to end	Day	7% 10% 5% 12% 6% 6% 5% 3 5% 5% 36%	2772
February	1st to 10th	Day	9% 11% 4 10% 8% 6% 5% 4 5% 6% 32%	1600
	11th to 20th	Day	10% 13% 4 13% 7% 6% 4 3 5% 6% 26%	1663
	21st to end	Day	11% 13% 4 8% 5% 5% 4 4 5% 6% 34%	1543
March	1st to 10th	Day	12% 14% 4 8% 5% 7% 6% 5% 5% 6% 29%	3138
	11th to 20th	Day	20% 20% 4 8% 5% 4 4 4 4 5% 23%	3480
	21st to end	Day	20% 16% 4 9% 4 4 3 3 4 5% 29%	3816
April	1st to 10th	Day	18% 13% 4 9% 5% 4 4 3 5% 6% 30%	2330
	11th to 20th	Day	16% 10% 3 8% 4 4 5% 4 5% 7% 36%	2442
	21st to end	Day	22% 10% 3 7% 4 3 4 3 6% 6% 32%	2470
May	1st to 10th	Day	15% 10% 4 10% 6% 5% 5% 3 5% 7% 30%	4120
	11th to 20th	Day	21% 7% 2 7% 4 3 5% 4 6% 7% 35%	4699
	21st to end	Day	21% 9% 3 8% 5% 5% 5% 4 6% 6% 28%	5185
June	1st to 10th	Day	23% 8% 3 7% 5% 5% 4 3 5% 5% 33%	2850
	11th to 20th	Day	20% 6% 3 6% 5% 4 4 4 6% 8% 34%	2850
	21st to end	Day	24% 8% 3 7% 4 5% 4 5% 6% 7% 28%	2850
July	1st to 10th	Day	15% 7% 2 7% 5% 6% 5% 4 7% 8% 35%	4760
	11th to 20th	Day	15% 7% 2 6% 5% 6% 5% 5% 7% 9% 34%	4760
	21st to end	Day	13% 6% 2 6% 5% 5% 5% 4 7% 9% 39%	4955
August	1st to 10th	Day	14% 5% 2 7% 5% 6% 7% 5% 8% 9% 31%	4278
	11th to 20th	Day	19% 7% 2 7% 5% 6% 6% 5% 7% 8% 27%	4045
	21st to end	Day	14% 5% 2 7% 5% 5% 6% 5% 6% 8% 38%	4532
September	1st to 10th	Day	17% 8% 2 6% 5% 4 5% 3 5% 7% 37%	2313
	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	19% 10% 3 10% 6% 5% 4 4 4 6% 29%	1603
	11th to 20th	Day	22% 13% 4 8% 4 5% 5% 3 5% 6% 26%	1520
	21st to end	Day	21% 14% 5% 8% 5% 4 3 3 4 5% 27%	1386
December	1st to 10th	Day	17% 15% 4 7% 4 5% 4 4 6% 6% 28%	1330
	11th to 20th	Day	18% 14% 5% 9% 4 3 3 2 4 4 35%	1668
	21st to end	Day	14% 15% 5% 10% 4 3 2 3 4 5% 34%	2431
January	1st to 10th	Night	10% 18% 6% 12% 6% 4 4 3 4 4 29%	4748
	11th to 20th	Night	13% 15% 6% 9% 5% 6% 5% 4 5% 6% 26%	4629
	21st to end	Night	6% 10% 5% 11% 5% 4 5% 4 5% 6% 39%	4884
February	1st to 10th	Night	9% 13% 5% 10% 7% 5% 4 3 5% 5% 35%	2580
	11th to 20th	Night	12% 15% 5% 10% 6% 4 4 4 5% 6% 28%	2403
	21st to end	Night	11% 14% 4 9% 6% 6% 5% 4 5% 5% 30%	1908
March	1st to 10th	Night	13% 12% 4 8% 7% 6% 6% 4 5% 6% 31%	3701
	11th to 20th	Night	19% 18% 5% 10% 5% 4 3 3 4 5% 23%	3479
	21st to end	Night	21% 17% 4 6% 5% 3 4 3 4 5% 28%	3816
April	1st to 10th	Night	24% 11% 3 6% 5% 3 4 3 4 5% 32%	1846
	11th to 20th	Night	20% 9% 2 5% 5% 4 4 3 5% 7% 36%	1688
	21st to end	Night	24% 11% 2 6% 3 3 3 2 4 6% 37%	1710
May	1st to 10th	Night	19% 7% 4 9% 5% 5% 4 3 6% 7% 31%	2818
	11th to 20th	Night	18% 9% 3 7% 5% 4 5% 4 4 6% 36%	2234
	21st to end	Night	21% 9% 3 9% 6% 5% 5% 4 5% 7% 26%	2401
June	1st to 10th	Night	23% 8% 2 5% 5% 4 4 4 5% 8% 33%	1330
	11th to 20th	Night	18% 6% 3 7% 5% 4 4 4 6% 9% 34%	1330
	21st to end	Night	25% 7% 3 7% 5% 4 5% 4 5% 5% 30%	1330
July	1st to 10th	Night	16% 6% 2 6% 4 5% 5% 5% 6% 7% 38%	2210
	11th to 20th	Night	13% 6% 2 6% 4 6% 5% 5% 7% 9% 36%	2210
	21st to end	Night	12% 5% 1 5% 4 4 4 5% 6% 8% 45%	2600
August	1st to 10th	Night	17% 6% 3 7% 5% 5% 5% 5% 6% 8% 34%	2620
	11th to 20th	Night	18% 7% 3 7% 5% 4 5% 5% 7% 9% 31%	2782
	21st to end	Night	15% 5% 2 6% 4 4 5% 4 6% 6% 42%	3124
September	1st to 10th	Night	17% 8% 3 6% 4 5% 4 4 5% 6% 38%	1866
	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%	2548
	11th to 20th	Night	20% 12% 4 7% 5% 4 4 4 4 6% 30%	2660
	21st to end	Night	19% 16% 5% 8% 5% 4 4 3 4 5% 26%	2793
December	1st to 10th	Night	19% 16% 4 7% 5% 4 4 3 4 4 29%	2850
	11th to 20th	Night	21% 14% 4 8% 4 4 3 2 3 5% 32%	3531
	21st to end	Night	15% 14% 5% 10% 5% 4 4 3 5% 6% 30%	5236

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% 6% 13% 18% 6%	2208
	11th to 20th	Day	56% 10% 12% 16% 5% 1	2334
	21st to end	Day	46% 8% 10% 20% 16% 1	2772
February	1st to 10th	Day	51% 7% 10% 19% 10% 2	1600
	11th to 20th	Day	59% 6% 11% 15% 9%	1671
	21st to end	Day	49% 5% 10% 23% 11% 1	1543
March	1st to 10th	Day	51% 11% 11% 19% 7% 1	3141
	11th to 20th	Day	62% 6% 9% 15% 7% 1	3480
	21st to end	Day	57% 5% 9% 17% 9% 3	3816
April	1st to 10th	Day	54% 6% 10% 15% 13% 2	2330
	11th to 20th	Day	46% 7% 13% 22% 11% 1	2442
	21st to end	Day	51% 6% 11% 18% 12% 2	2470
May	1st to 10th	Day	49% 11% 15% 17% 7% 1	4134
	11th to 20th	Day	46% 10% 15% 19% 10% 1	4703
	21st to end	Day	51% 10% 12% 18% 9% 1	5185
June	1st to 10th	Day	51% 7% 11% 19% 9% 3	2850
	11th to 20th	Day	47% 8% 14% 17% 12% 2	2850
	21st to end	Day	53% 9% 13% 15% 9% 1	2850
July	1st to 10th	Day	44% 9% 14% 26% 7%	4685
	11th to 20th	Day	44% 10% 18% 21% 6%	4679
	21st to end	Day	39% 11% 18% 24% 9%	4797
August	1st to 10th	Day	45% 12% 19% 18% 6%	4264
	11th to 20th	Day	51% 11% 21% 14% 4	4084
	21st to end	Day	41% 10% 18% 20% 10%	4532
September	1st to 10th	Day	45% 10% 16% 19% 10%	2313
	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% 8% 16% 14% 7%	1603
	11th to 20th	Day	59% 7% 13% 17% 3	1520
	21st to end	Day	60% 6% 13% 15% 5% 1	1386
December	1st to 10th	Day	56% 8% 14% 17% 5% 1	1330
	11th to 20th	Day	54% 6% 9% 21% 10%	1668
	21st to end	Day	52% 6% 12% 18% 8% 4	2431
January	1st to 10th	Night	59% 6% 8% 17% 9% 1	4748
	11th to 20th	Night	55% 10% 12% 17% 5% 1	4629
	21st to end	Night	43% 9% 12% 23% 14%	4884
February	1st to 10th	Night	52% 5% 9% 19% 13% 2	2580
	11th to 20th	Night	55% 7% 11% 17% 9% 1	2406
	21st to end	Night	54% 7% 8% 19% 10% 2	1908
March	1st to 10th	Night	52% 9% 11% 17% 10% 1	3711
	11th to 20th	Night	62% 6% 8% 15% 7% 1	3480
	21st to end	Night	56% 7% 8% 16% 11% 1	3816
April	1st to 10th	Night	54% 6% 9% 13% 14% 3	1846
	11th to 20th	Night	47% 7% 9% 19% 16% 2	1688
	21st to end	Night	50% 4 10% 18% 16% 3	1710
May	1st to 10th	Night	48% 11% 15% 14% 11% 1	2824
	11th to 20th	Night	48% 7% 12% 21% 11% 1	2235
	21st to end	Night	53% 10% 10% 16% 10% 1	2402
June	1st to 10th	Night	49% 7% 13% 19% 11% 2	1330
	11th to 20th	Night	46% 8% 14% 17% 13% 2	1330
	21st to end	Night	55% 7% 9% 18% 11% 1	1330
July	1st to 10th	Night	42% 10% 14% 25% 9%	2175
	11th to 20th	Night	41% 9% 18% 25% 8%	2168
	21st to end	Night	35% 8% 23% 18% 15%	2517
August	1st to 10th	Night	45% 9% 18% 21% 7%	2610
	11th to 20th	Night	46% 11% 24% 14% 4	2809
	21st to end	Night	38% 9% 15% 27% 11%	3124
September	1st to 10th	Night	44% 8% 14% 24% 9%	1866
	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	54% 8% 12% 16% 8% 1	2548
	11th to 20th	Night	55% 8% 14% 18% 5%	2660
	21st to end	Night	60% 7% 11% 13% 8% 1	2793
December	1st to 10th	Night	58% 7% 12% 16% 6%	2850
	11th to 20th	Night	55% 5% 11% 18% 10%	3532
	21st to end	Night	54% 9% 12% 13% 9% 3	5236

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% 14% 33% 21% 8%	180
	11th to 20th	Day	21% 24% 27% 21% 7% 1	180
	21st to end	Day	19% 19% 30% 23% 6% 3	198
February	1st to 10th	Day	18% 16% 37% 19% 7% 3	260
	11th to 20th	Day	14% 21% 41% 18% 6% 1	366
	21st to end	Day	22% 20% 40% 12% 5% 1	370
March	1st to 10th	Day	23% 18% 33% 19% 7%	460
	11th to 20th	Day	23% 18% 29% 21% 8% 1	460
	21st to end	Day	25% 22% 32% 15% 5% 2	506
April	1st to 10th	Day	25% 23% 29% 17% 5%	460
	11th to 20th	Day	22% 18% 33% 21% 5% 1	452
	21st to end	Day	25% 19% 33% 16% 6% 1	460
May	1st to 10th	Day	27% 17% 27% 22% 6% 1	464
	11th to 20th	Day	23% 14% 29% 23% 10% 1	674
	21st to end	Day	27% 21% 27% 18% 7% 1	735
June	1st to 10th	Day	28% 12% 31% 21% 7% 1	680
	11th to 20th	Day	23% 15% 28% 21% 12% 2	680
	21st to end	Day	25% 12% 31% 23% 8% 1	680
July	1st to 10th	Day	21% 12% 32% 24% 9% 1	670
	11th to 20th	Day	19% 9% 30% 29% 12% 1	668
	21st to end	Day	19% 10% 30% 29% 10% 2	621
August	1st to 10th	Day	19% 12% 30% 27% 9% 2	486
	11th to 20th	Day	19% 11% 30% 27% 11% 2	479
	21st to end	Day	18% 12% 31% 24% 11% 3	539
September	1st to 10th	Day	22% 14% 33% 20% 8% 3	490
	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	28% 18% 35% 15% 5% 1	374
	11th to 20th	Day	28% 15% 28% 22% 6% 1	370
	21st to end	Day	26% 23% 30% 17% 4	236
December	1st to 10th	Day	24% 16% 28% 18% 11% 3	180
	11th to 20th	Day	25% 24% 33% 13% 4 1	180
	21st to end	Day	24% 21% 33% 17% 4 1	198
January	1st to 10th	Night	23% 13% 37% 22% 4	850
	11th to 20th	Night	21% 18% 33% 22% 5%	812
	21st to end	Night	13% 17% 35% 28% 7%	836
February	1st to 10th	Night	14% 19% 38% 21% 8% 1	760
	11th to 20th	Night	20% 16% 36% 21% 7%	743
	21st to end	Night	18% 14% 37% 22% 8% 1	628
March	1st to 10th	Night	18% 16% 35% 25% 6% 1	760
	11th to 20th	Night	19% 21% 30% 23% 7%	760
	21st to end	Night	23% 18% 30% 22% 7%	836
April	1st to 10th	Night	29% 15% 27% 24% 6%	701
	11th to 20th	Night	25% 14% 28% 23% 9% 1	564
	21st to end	Night	29% 13% 27% 22% 8% 1	570
May	1st to 10th	Night	26% 12% 25% 28% 9% 1	570
	11th to 20th	Night	23% 7% 28% 30% 11%	407
	21st to end	Night	24% 11% 28% 27% 10%	411
June	1st to 10th	Night	26% 6% 27% 31% 11%	380
	11th to 20th	Night	22% 6% 23% 33% 15% 2	380
	21st to end	Night	25% 6% 24% 33% 12% 1	380
July	1st to 10th	Night	19% 5% 26% 36% 12% 1	370
	11th to 20th	Night	17% 5% 20% 42% 13% 2	368
	21st to end	Night	19% 7% 17% 37% 19% 1	416
August	1st to 10th	Night	20% 5% 18% 37% 19% 2	440
	11th to 20th	Night	21% 6% 22% 35% 16% 1	562
	21st to end	Night	18% 6% 22% 36% 17% 1	627
September	1st to 10th	Night	22% 9% 27% 30% 12% 1	650
	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	29% 16% 28% 21% 5% 1	800
	11th to 20th	Night	25% 19% 29% 20% 6% 1	850
	21st to end	Night	27% 18% 31% 18% 4	850
December	1st to 10th	Night	28% 14% 29% 22% 6% 1	850
	11th to 20th	Night	26% 22% 30% 15% 6%	850
	21st to end	Night	26% 18% 28% 22% 5% 2	935

Page generated at 2024-11-01 22:47:34. Version ac07

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