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 2024-03-28.

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% 9% 4 7% 6% 3 5% 5% 5% 7% 32%	78213
	Night	17% 11% 4 7% 6% 3 4 4 5% 6% 32%	81806
Transparency	Day	51% 8% 13% 18% 9% 1	77901
	Night	52% 7% 12% 18% 10% 1	81653
Seeing	Day	23% 16% 30% 21% 8% 2	15055
	Night	23% 14% 29% 25% 9% 1	23145

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% 12% 5% 11% 8% 3 5% 4 4 5% 29%	2207
	11th to 20th	Day	11% 16% 7% 11% 7% 4 4 5% 5% 6% 23%	2334
	21st to end	Day	7% 9% 5% 10% 7% 4 5% 4 5% 5% 37%	2772
February	1st to 10th	Day	9% 9% 5% 9% 9% 5% 5% 5% 4 6% 33%	1600
	11th to 20th	Day	10% 13% 5% 13% 8% 6% 5% 4 5% 6% 26%	1663
	21st to end	Day	11% 11% 5% 8% 5% 4 5% 5% 4 7% 34%	1543
March	1st to 10th	Day	14% 13% 5% 8% 5% 4 5% 5% 4 6% 31%	1906
	11th to 20th	Day	16% 13% 5% 7% 7% 3 5% 5% 4 6% 30%	2090
	21st to end	Day	14% 16% 4 7% 5% 3 4 4 4 5% 33%	2255
April	1st to 10th	Day	19% 12% 5% 8% 6% 2 4 4 5% 6% 28%	2206
	11th to 20th	Day	16% 8% 3 7% 5% 2 5% 5% 5% 7% 37%	2312
	21st to end	Day	22% 9% 3 6% 5% 3 4 4 6% 6% 32%	2340
May	1st to 10th	Day	23% 9% 3 7% 5% 4 4 4 4 6% 31%	2340
	11th to 20th	Day	21% 7% 3 6% 5% 3 5% 5% 5% 7% 34%	2639
	21st to end	Day	22% 7% 3 5% 5% 3 5% 5% 6% 6% 33%	2919
June	1st to 10th	Day	24% 7% 3 6% 6% 4 4 4 5% 5% 32%	2700
	11th to 20th	Day	21% 6% 3 5% 5% 3 5% 4 6% 8% 34%	2700
	21st to end	Day	24% 7% 3 6% 5% 3 5% 5% 6% 8% 28%	2700
July	1st to 10th	Day	18% 7% 3 6% 6% 5% 6% 6% 7% 9% 28%	2700
	11th to 20th	Day	17% 5% 3 5% 7% 3 6% 6% 6% 9% 33%	2700
	21st to end	Day	16% 7% 3 6% 6% 4 7% 5% 8% 8% 31%	2829
August	1st to 10th	Day	18% 6% 3 7% 7% 5% 7% 6% 7% 8% 27%	2430
	11th to 20th	Day	17% 7% 2 5% 5% 4 6% 6% 6% 8% 33%	2304
	21st to end	Day	16% 7% 3 6% 6% 3 5% 6% 6% 8% 34%	2574
September	1st to 10th	Day	18% 8% 2 5% 6% 4 5% 4 5% 6% 37%	2192
	11th to 20th	Day	23% 7% 2 4 5% 3 4 3 4 6% 39%	1980
	21st to end	Day	20% 6% 2 6% 5% 3 4 4 4 6% 39%	1980
October	1st to 10th	Day	19% 6% 2 6% 6% 3 5% 4 4 6% 36%	1872
	11th to 20th	Day	27% 7% 3 6% 6% 4 5% 5% 5% 6% 26%	1733
	21st to end	Day	26% 11% 3 6% 7% 3 4 3 5% 6% 25%	1782
November	1st to 10th	Day	19% 9% 4 8% 8% 4 5% 4 4 6% 29%	1576
	11th to 20th	Day	22% 12% 5% 8% 5% 3 5% 4 5% 6% 26%	1520
	21st to end	Day	22% 13% 6% 7% 6% 4 4 4 4 5% 27%	1386
December	1st to 10th	Day	18% 13% 5% 6% 5% 4 5% 4 5% 7% 28%	1330
	11th to 20th	Day	18% 13% 5% 8% 6% 2 3 3 4 4 35%	1668
	21st to end	Day	15% 14% 5% 9% 5% 2 2 3 4 5% 34%	2431
January	1st to 10th	Night	10% 17% 7% 11% 7% 3 5% 4 4 4 29%	4748
	11th to 20th	Night	14% 14% 6% 8% 6% 5% 5% 5% 5% 6% 26%	4629
	21st to end	Night	6% 10% 6% 9% 7% 3 4 5% 5% 5% 40%	4884
February	1st to 10th	Night	9% 11% 6% 10% 7% 3 5% 4 5% 6% 35%	2580
	11th to 20th	Night	12% 14% 6% 9% 7% 4 5% 5% 5% 6% 28%	2403
	21st to end	Night	11% 12% 6% 9% 7% 5% 5% 5% 5% 5% 30%	1908
March	1st to 10th	Night	12% 13% 5% 8% 7% 4 5% 3 4 6% 31%	2260
	11th to 20th	Night	14% 13% 6% 8% 6% 3 4 4 4 5% 32%	2089
	21st to end	Night	15% 14% 4 5% 6% 3 5% 4 4 6% 34%	2256
April	1st to 10th	Night	24% 11% 4 6% 6% 3 4 3 3 6% 30%	1750
	11th to 20th	Night	19% 9% 3 4 5% 3 4 4 5% 7% 37%	1598
	21st to end	Night	25% 9% 3 5% 4 2 3 3 4 6% 37%	1620
May	1st to 10th	Night	26% 7% 4 7% 5% 3 4 4 4 6% 31%	1617
	11th to 20th	Night	20% 9% 3 5% 6% 3 4 4 3 5% 37%	1270
	21st to end	Night	22% 6% 3 6% 7% 4 5% 6% 5% 7% 30%	1356
June	1st to 10th	Night	23% 7% 3 5% 5% 3 4 4 5% 8% 32%	1260
	11th to 20th	Night	19% 5% 3 6% 6% 3 4 5% 5% 9% 34%	1260
	21st to end	Night	25% 7% 3 6% 6% 3 5% 5% 4 5% 30%	1260
July	1st to 10th	Night	18% 7% 3 5% 7% 4 5% 6% 6% 8% 31%	1260
	11th to 20th	Night	16% 6% 3 5% 6% 4 5% 5% 7% 9% 33%	1260
	21st to end	Night	18% 7% 2 5% 5% 4 5% 6% 7% 8% 33%	1487
August	1st to 10th	Night	16% 7% 3 6% 5% 3 5% 7% 6% 9% 34%	1490
	11th to 20th	Night	19% 7% 3 5% 5% 2 5% 5% 7% 8% 33%	1596
	21st to end	Night	17% 6% 2 5% 5% 3 5% 5% 7% 8% 38%	1782
September	1st to 10th	Night	17% 8% 3 5% 4 4 4 5% 5% 7% 38%	1767
	11th to 20th	Night	22% 6% 2 5% 5% 3 4 4 5% 6% 39%	1980
	21st to end	Night	20% 5% 2 5% 5% 2 3 3 5% 7% 43%	1980
October	1st to 10th	Night	19% 7% 3 5% 5% 3 5% 4 5% 5% 39%	2087
	11th to 20th	Night	25% 8% 3 5% 5% 3 5% 5% 5% 6% 31%	2223
	21st to end	Night	26% 9% 3 5% 5% 3 4 4 5% 5% 32%	2574
November	1st to 10th	Night	22% 11% 4 6% 5% 3 4 4 4 6% 30%	2502
	11th to 20th	Night	20% 11% 4 6% 6% 3 5% 4 4 6% 30%	2660
	21st to end	Night	20% 16% 5% 8% 6% 3 4 4 4 5% 26%	2793
December	1st to 10th	Night	20% 15% 5% 6% 6% 3 4 4 4 5% 29%	2850
	11th to 20th	Night	22% 13% 5% 7% 5% 2 3 3 3 5% 32%	3531
	21st to end	Night	15% 13% 5% 9% 6% 3 4 4 4 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	53% 7% 10% 18% 9% 2	1909
	11th to 20th	Day	54% 6% 11% 16% 11% 2	2090
	21st to end	Day	54% 5% 10% 16% 13% 2	2255
April	1st to 10th	Day	56% 6% 10% 14% 13% 2	2206
	11th to 20th	Day	46% 6% 13% 22% 11% 1	2312
	21st to end	Day	52% 6% 11% 18% 12% 1	2340
May	1st to 10th	Day	54% 8% 10% 17% 9% 2	2340
	11th to 20th	Day	48% 7% 14% 18% 12% 1	2643
	21st to end	Day	50% 8% 10% 20% 12% 1	2919
June	1st to 10th	Day	53% 6% 11% 17% 9% 3	2700
	11th to 20th	Day	47% 8% 13% 18% 12% 2	2700
	21st to end	Day	53% 10% 13% 15% 8% 1	2700
July	1st to 10th	Day	49% 11% 16% 18% 6%	2625
	11th to 20th	Day	46% 9% 16% 19% 9%	2619
	21st to end	Day	48% 12% 16% 18% 6%	2671
August	1st to 10th	Day	52% 12% 17% 16% 3	2416
	11th to 20th	Day	46% 10% 20% 17% 6%	2304
	21st to end	Day	46% 11% 17% 20% 6%	2574
September	1st to 10th	Day	46% 10% 16% 19% 10%	2192
	11th to 20th	Day	47% 7% 14% 24% 8%	1980
	21st to end	Day	46% 8% 14% 23% 9%	1980
October	1st to 10th	Day	48% 8% 15% 17% 11% 1	1872
	11th to 20th	Day	57% 10% 13% 16% 4	1733
	21st to end	Day	61% 6% 10% 15% 7% 1	1782
November	1st to 10th	Day	55% 7% 16% 14% 7%	1576
	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	54% 6% 9% 19% 11% 1	2270
	11th to 20th	Night	53% 6% 9% 19% 12% 2	2090
	21st to end	Night	52% 5% 10% 17% 14% 2	2256
April	1st to 10th	Night	56% 6% 9% 12% 14% 3	1750
	11th to 20th	Night	46% 7% 10% 19% 16% 3	1598
	21st to end	Night	50% 4 10% 18% 15% 3	1620
May	1st to 10th	Night	54% 6% 9% 18% 11% 1	1617
	11th to 20th	Night	48% 6% 12% 19% 14% 1	1271
	21st to end	Night	52% 8% 8% 17% 13% 2	1357
June	1st to 10th	Night	50% 7% 12% 18% 11% 2	1260
	11th to 20th	Night	46% 7% 14% 18% 13% 2	1260
	21st to end	Night	55% 7% 9% 17% 11% 1	1260
July	1st to 10th	Night	49% 9% 14% 20% 7%	1225
	11th to 20th	Night	46% 9% 14% 21% 10%	1218
	21st to end	Night	47% 9% 17% 18% 8%	1404
August	1st to 10th	Night	46% 11% 19% 17% 6%	1480
	11th to 20th	Night	46% 12% 18% 17% 7% 1	1596
	21st to end	Night	42% 10% 17% 25% 7%	1782
September	1st to 10th	Night	45% 9% 14% 23% 9%	1767
	11th to 20th	Night	46% 8% 15% 21% 9% 1	1980
	21st to end	Night	42% 6% 14% 25% 13%	1980
October	1st to 10th	Night	47% 6% 13% 22% 10% 2	2087
	11th to 20th	Night	53% 9% 14% 18% 7%	2223
	21st to end	Night	54% 7% 15% 19% 5% 1	2574
November	1st to 10th	Night	55% 8% 12% 16% 8% 1	2502
	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	23% 22% 33% 15% 5% 2	490
April	1st to 10th	Day	25% 24% 30% 17% 4	420
	11th to 20th	Day	23% 17% 34% 20% 5% 1	412
	21st to end	Day	26% 17% 32% 17% 6% 1	420
May	1st to 10th	Day	28% 16% 28% 22% 5% 1	423
	11th to 20th	Day	23% 14% 29% 22% 9% 1	624
	21st to end	Day	27% 20% 27% 18% 7% 1	680
June	1st to 10th	Day	29% 12% 31% 20% 6% 1	630
	11th to 20th	Day	24% 13% 28% 21% 12% 1	630
	21st to end	Day	25% 11% 30% 23% 9% 1	630
July	1st to 10th	Day	22% 11% 31% 25% 10% 1	620
	11th to 20th	Day	19% 9% 29% 30% 13% 1	618
	21st to end	Day	19% 10% 29% 29% 10% 3	573
August	1st to 10th	Day	20% 10% 29% 28% 10% 2	446
	11th to 20th	Day	19% 11% 29% 28% 11% 2	439
	21st to end	Day	18% 13% 30% 24% 12% 3	495
September	1st to 10th	Day	22% 14% 32% 20% 8% 3	450
	11th to 20th	Day	28% 16% 25% 22% 6% 3	450
	21st to end	Day	20% 17% 33% 19% 8% 3	450
October	1st to 10th	Day	21% 18% 30% 20% 10% 1	396
	11th to 20th	Day	29% 16% 29% 14% 10% 1	360
	21st to end	Day	35% 14% 23% 18% 8% 1	396
November	1st to 10th	Day	28% 18% 35% 15% 5% 1	365
	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	22% 18% 30% 23% 7%	821
April	1st to 10th	Night	29% 15% 27% 23% 5%	665
	11th to 20th	Night	24% 15% 29% 22% 9% 1	534
	21st to end	Night	29% 12% 27% 22% 9% 1	540
May	1st to 10th	Night	27% 13% 24% 29% 8% 1	540
	11th to 20th	Night	24% 7% 28% 31% 10% 1	386
	21st to end	Night	25% 11% 28% 26% 10%	389
June	1st to 10th	Night	26% 6% 27% 31% 10%	360
	11th to 20th	Night	22% 6% 22% 33% 16% 2	360
	21st to end	Night	26% 6% 23% 33% 12% 1	360
July	1st to 10th	Night	20% 5% 27% 35% 13% 1	350
	11th to 20th	Night	18% 5% 20% 41% 14% 2	348
	21st to end	Night	20% 7% 16% 35% 20% 2	394
August	1st to 10th	Night	20% 5% 17% 37% 20% 2	416
	11th to 20th	Night	21% 6% 22% 34% 16% 1	532
	21st to end	Night	19% 6% 23% 35% 16% 1	594
September	1st to 10th	Night	21% 9% 26% 30% 13% 1	615
	11th to 20th	Night	25% 8% 28% 25% 13% 1	720
	21st to end	Night	23% 10% 27% 28% 12% 1	720
October	1st to 10th	Night	21% 16% 25% 27% 10% 1	720
	11th to 20th	Night	26% 11% 27% 24% 11% 1	720
	21st to end	Night	31% 13% 27% 21% 7% 1	792
November	1st to 10th	Night	29% 16% 28% 21% 5% 1	785
	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 2024-03-24 23:37:03. Version ac07

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