CEGEP Beauce-Appalaches
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the CEGEP Beauce-Appalaches clear sky chart from 2005-11-06 to 2025-02-06.

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%	107888
	Night	17% 14% 5% 11% 6% 5% 4 3 4 5% 26%	110403
Transparency	Day	58% 6% 11% 17% 8% 1	111404
	Night	60% 5% 10% 16% 7% 1	115052
Seeing	Day	28% 17% 28% 18% 8% 2	15531
	Night	26% 14% 28% 24% 8% 1	24194

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% 21% 8% 18% 9% 8% 4 3 3 3 9%	3597
	11th to 20th	Day	10% 16% 9% 24% 12% 4 3 2 2 3 15%	3570
	21st to end	Day	7% 12% 8% 18% 7% 8% 6% 3 5% 5% 20%	3960
February	1st to 10th	Day	13% 17% 6% 13% 10% 7% 4 3 4 4 20%	1609
	11th to 20th	Day	13% 19% 8% 14% 7% 5% 4 3 3 4 19%	1823
	21st to end	Day	12% 17% 5% 13% 6% 6% 4 3 5% 5% 22%	1570
March	1st to 10th	Day	20% 16% 4 9% 6% 4 3 3 4 5% 26%	3116
	11th to 20th	Day	18% 23% 5% 12% 5% 4 3 2 3 3 21%	3370
	21st to end	Day	18% 16% 5% 9% 5% 3 3 2 4 4 30%	3995
April	1st to 10th	Day	22% 17% 3 10% 4 3 3 2 5% 5% 25%	2280
	11th to 20th	Day	20% 13% 4 6% 4 3 3 3 3 5% 35%	2360
	21st to end	Day	24% 12% 3 8% 5% 3 3 3 4 6% 29%	2470
May	1st to 10th	Day	21% 10% 3 8% 6% 6% 5% 3 5% 5% 28%	4106
	11th to 20th	Day	21% 9% 3 7% 5% 5% 5% 4 6% 7% 26%	4387
	21st to end	Day	16% 7% 3 8% 6% 5% 6% 5% 7% 7% 29%	4887
June	1st to 10th	Day	24% 10% 2 6% 5% 5% 5% 4 7% 8% 26%	2850
	11th to 20th	Day	19% 7% 3 6% 5% 5% 6% 4 6% 8% 33%	2850
	21st to end	Day	21% 10% 4 9% 7% 5% 5% 4 5% 6% 24%	2850
July	1st to 10th	Day	15% 7% 4 8% 7% 6% 6% 5% 7% 8% 27%	4480
	11th to 20th	Day	15% 7% 3 8% 6% 5% 6% 5% 8% 8% 30%	4440
	21st to end	Day	15% 7% 2 6% 4 4 5% 4 6% 7% 39%	4814
August	1st to 10th	Day	17% 7% 3 8% 6% 6% 6% 6% 7% 8% 26%	4309
	11th to 20th	Day	18% 7% 3 9% 7% 6% 6% 5% 7% 8% 25%	4045
	21st to end	Day	20% 7% 3 6% 4 5% 4 3 5% 7% 35%	4373
September	1st to 10th	Day	16% 7% 2 7% 4 4 5% 4 5% 8% 36%	2274
	11th to 20th	Day	18% 7% 2 6% 3 3 3 3 5% 7% 41%	2090
	21st to end	Day	19% 8% 3 6% 4 4 4 4 6% 9% 33%	2090
October	1st to 10th	Day	21% 11% 3 7% 5% 5% 4 3 5% 7% 30%	2090
	11th to 20th	Day	20% 13% 4 8% 6% 6% 4 4 4 4 26%	1761
	21st to end	Day	24% 17% 5% 9% 4 3 4 3 5% 5% 22%	1881
November	1st to 10th	Day	19% 16% 5% 8% 5% 4 4 3 4 5% 27%	1761
	11th to 20th	Day	19% 16% 7% 12% 4 4 3 3 4 5% 24%	1800
	21st to end	Day	20% 18% 5% 12% 6% 4 3 3 4 5% 19%	1506
December	1st to 10th	Day	17% 18% 7% 15% 7% 5% 5% 3 4 3 16%	2280
	11th to 20th	Day	18% 16% 6% 11% 6% 4 4 3 5% 4 24%	2618
	21st to end	Day	19% 19% 5% 14% 5% 4 4 4 4 4 18%	3626
January	1st to 10th	Night	13% 17% 9% 22% 8% 6% 4 3 4 3 11%	6349
	11th to 20th	Night	10% 21% 8% 23% 10% 5% 3 3 3 3 12%	6315
	21st to end	Night	8% 15% 7% 14% 8% 7% 7% 5% 5% 5% 21%	6996
February	1st to 10th	Night	12% 17% 5% 12% 9% 7% 5% 2 4 5% 22%	2680
	11th to 20th	Night	12% 17% 7% 16% 7% 7% 6% 3 3 4 19%	2242
	21st to end	Night	13% 17% 6% 10% 7% 4 4 4 4 4 28%	1884
March	1st to 10th	Night	22% 16% 4 8% 5% 3 5% 2 3 5% 27%	3724
	11th to 20th	Night	17% 20% 6% 11% 6% 4 4 2 3 4 23%	3589
	21st to end	Night	21% 16% 5% 8% 5% 3 3 2 4 4 28%	3636
April	1st to 10th	Night	22% 16% 4 7% 4 3 3 3 5% 5% 28%	1900
	11th to 20th	Night	20% 12% 2 7% 5% 4 4 3 4 6% 32%	1768
	21st to end	Night	21% 12% 3 8% 5% 4 4 3 4 5% 30%	1710
May	1st to 10th	Night	24% 8% 3 7% 5% 4 4 4 6% 6% 28%	2834
	11th to 20th	Night	21% 10% 3 7% 5% 4 4 3 4 5% 33%	2537
	21st to end	Night	18% 7% 3 6% 4 4 4 4 6% 8% 37%	2688
June	1st to 10th	Night	23% 10% 3 8% 5% 4 5% 3 5% 6% 28%	1330
	11th to 20th	Night	18% 6% 3 7% 4 4 4 4 6% 7% 36%	1330
	21st to end	Night	19% 8% 3 9% 4 4 5% 4 5% 7% 31%	1330
July	1st to 10th	Night	14% 8% 3 8% 6% 5% 6% 5% 6% 8% 32%	2476
	11th to 20th	Night	18% 6% 2 8% 5% 5% 4 4 5% 7% 35%	2520
	21st to end	Night	15% 7% 2 6% 4 4 5% 4 6% 8% 41%	2739
August	1st to 10th	Night	20% 7% 3 7% 5% 5% 4 4 6% 8% 32%	2588
	11th to 20th	Night	15% 8% 3 10% 6% 6% 6% 5% 5% 7% 29%	2782
	21st to end	Night	17% 8% 3 7% 4 4 5% 3 5% 7% 37%	3279
September	1st to 10th	Night	16% 8% 3 6% 5% 4 4 3 6% 7% 38%	1905
	11th to 20th	Night	17% 6% 2 6% 4 4 3 3 5% 6% 44%	2090
	21st to end	Night	17% 7% 3 6% 4 4 4 3 5% 7% 41%	2090
October	1st to 10th	Night	19% 9% 3 6% 4 3 4 4 6% 6% 36%	2090
	11th to 20th	Night	22% 11% 3 8% 6% 5% 4 3 4 5% 29%	2416
	21st to end	Night	22% 15% 4 8% 4 3 4 3 5% 5% 28%	2717
November	1st to 10th	Night	20% 15% 4 8% 5% 5% 4 4 4 5% 28%	2537
	11th to 20th	Night	18% 13% 6% 10% 5% 4 4 3 4 5% 28%	2600
	21st to end	Night	19% 20% 6% 10% 5% 4 3 3 4 4 22%	2890
December	1st to 10th	Night	16% 18% 10% 18% 9% 5% 3 2 3 3 11%	4910
	11th to 20th	Night	19% 18% 6% 15% 7% 4 4 2 3 4 16%	5591
	21st to end	Night	19% 19% 6% 10% 5% 4 4 3 4 5% 22%	7341

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	81% 4 6% 7% 2	3598
	11th to 20th	Day	77% 5% 3 10% 4 1	3600
	21st to end	Day	68% 5% 5% 10% 11% 1	3960
February	1st to 10th	Day	71% 4 5% 11% 8% 2	1609
	11th to 20th	Day	72% 3 7% 10% 6% 1	1832
	21st to end	Day	63% 5% 8% 15% 6% 2	1570
March	1st to 10th	Day	62% 4 8% 14% 10% 2	3119
	11th to 20th	Day	69% 6% 7% 11% 6% 1	3370
	21st to end	Day	58% 5% 6% 15% 13% 3	3995
April	1st to 10th	Day	63% 4 8% 14% 9% 3	2280
	11th to 20th	Day	53% 4 8% 22% 12% 1	2360
	21st to end	Day	58% 4 8% 17% 11% 2	2470
May	1st to 10th	Day	57% 6% 9% 18% 9% 1	4120
	11th to 20th	Day	55% 7% 16% 15% 6% 1	4391
	21st to end	Day	49% 8% 11% 20% 11% 1	4887
June	1st to 10th	Day	56% 6% 10% 21% 6% 1	2850
	11th to 20th	Day	49% 6% 13% 22% 10% 1	2850
	21st to end	Day	61% 6% 9% 17% 7%	2850
July	1st to 10th	Day	51% 7% 15% 20% 7%	4410
	11th to 20th	Day	49% 8% 16% 23% 4	4365
	21st to end	Day	44% 6% 14% 29% 7%	4661
August	1st to 10th	Day	52% 9% 16% 20% 4	4295
	11th to 20th	Day	54% 8% 16% 16% 5%	4084
	21st to end	Day	49% 6% 14% 20% 11% 1	4373
September	1st to 10th	Day	45% 7% 15% 22% 10% 1	2274
	11th to 20th	Day	42% 5% 13% 28% 11%	2090
	21st to end	Day	46% 7% 13% 24% 10%	2090
October	1st to 10th	Day	56% 5% 11% 23% 5%	3480
	11th to 20th	Day	56% 4 13% 25% 2	2899
	21st to end	Day	55% 5% 14% 18% 8%	3081
November	1st to 10th	Day	61% 5% 10% 18% 6%	1761
	11th to 20th	Day	64% 4 9% 14% 7% 1	1800
	21st to end	Day	69% 6% 10% 12% 3	1506
December	1st to 10th	Day	74% 4 8% 8% 5%	2280
	11th to 20th	Day	65% 5% 7% 14% 10%	2618
	21st to end	Day	69% 4 7% 9% 9% 1	3626
January	1st to 10th	Night	79% 6% 6% 6% 2	6349
	11th to 20th	Night	79% 6% 4 8% 2	6360
	21st to end	Night	64% 7% 7% 11% 11% 1	6996
February	1st to 10th	Night	66% 4 8% 13% 8% 1	2680
	11th to 20th	Night	71% 5% 5% 11% 7% 1	2244
	21st to end	Night	61% 4 7% 15% 11% 1	1884
March	1st to 10th	Night	61% 5% 9% 16% 7% 2	3734
	11th to 20th	Night	65% 6% 10% 11% 7% 1	3590
	21st to end	Night	61% 3 6% 19% 9% 2	3636
April	1st to 10th	Night	60% 4 6% 16% 12% 2	1900
	11th to 20th	Night	54% 4 7% 21% 12% 2	1768
	21st to end	Night	57% 6% 8% 15% 11% 2	1710
May	1st to 10th	Night	53% 6% 13% 19% 8% 1	2840
	11th to 20th	Night	52% 5% 13% 20% 9% 1	2538
	21st to end	Night	45% 7% 16% 18% 14%	2689
June	1st to 10th	Night	57% 5% 11% 20% 7%	1330
	11th to 20th	Night	46% 7% 12% 23% 11% 2	1330
	21st to end	Night	52% 7% 13% 18% 9%	1330
July	1st to 10th	Night	47% 8% 19% 19% 6%	2436
	11th to 20th	Night	49% 6% 19% 21% 5%	2472
	21st to end	Night	41% 7% 19% 27% 6%	2651
August	1st to 10th	Night	51% 7% 16% 24% 3	2578
	11th to 20th	Night	52% 9% 17% 16% 5%	2809
	21st to end	Night	46% 6% 14% 21% 14%	3279
September	1st to 10th	Night	44% 6% 14% 26% 9% 1	1905
	11th to 20th	Night	41% 5% 16% 29% 9%	2090
	21st to end	Night	43% 7% 13% 24% 13%	2090
October	1st to 10th	Night	48% 5% 12% 26% 9%	3480
	11th to 20th	Night	56% 4 12% 25% 3	4017
	21st to end	Night	52% 4 16% 18% 9%	4467
November	1st to 10th	Night	59% 6% 11% 18% 6%	2537
	11th to 20th	Night	59% 5% 11% 14% 9% 1	2600
	21st to end	Night	67% 5% 10% 13% 4	2890
December	1st to 10th	Night	79% 4 7% 8% 2	4910
	11th to 20th	Night	72% 5% 5% 14% 4	5592
	21st to end	Night	66% 3 8% 15% 8%	7341

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	28% 23% 34% 14% 2	200
	11th to 20th	Day	32% 24% 28% 12% 5% 1	200
	21st to end	Day	23% 23% 35% 14% 3 1	220
February	1st to 10th	Day	36% 21% 28% 10% 5%	239
	11th to 20th	Day	27% 27% 32% 12% 2	444
	21st to end	Day	27% 25% 30% 15% 3	382
March	1st to 10th	Day	29% 23% 30% 13% 5%	460
	11th to 20th	Day	32% 21% 27% 13% 5% 1	460
	21st to end	Day	33% 20% 25% 13% 7% 2	506
April	1st to 10th	Day	38% 18% 24% 13% 5% 2	460
	11th to 20th	Day	34% 20% 24% 15% 5% 2	452
	21st to end	Day	34% 20% 28% 13% 5% 2	460
May	1st to 10th	Day	34% 17% 28% 16% 3 2	463
	11th to 20th	Day	27% 15% 30% 19% 6% 2	487
	21st to end	Day	23% 21% 35% 15% 5% 1	553
June	1st to 10th	Day	30% 13% 28% 21% 7% 1	680
	11th to 20th	Day	23% 14% 26% 25% 11% 1	680
	21st to end	Day	27% 13% 29% 19% 10% 1	680
July	1st to 10th	Day	21% 12% 34% 23% 8% 1	512
	11th to 20th	Day	20% 13% 36% 21% 10% 1	484
	21st to end	Day	23% 11% 30% 26% 8% 1	532
August	1st to 10th	Day	21% 13% 30% 24% 10% 2	486
	11th to 20th	Day	24% 9% 25% 25% 14% 2	479
	21st to end	Day	25% 13% 25% 22% 10% 6%	539
September	1st to 10th	Day	19% 14% 30% 21% 11% 4	490
	11th to 20th	Day	24% 10% 24% 21% 16% 6%	490
	21st to end	Day	23% 15% 22% 21% 13% 6%	490
October	1st to 10th	Day	26% 15% 24% 19% 13% 4	490
	11th to 20th	Day	34% 14% 24% 15% 11% 1	395
	21st to end	Day	38% 17% 24% 16% 5%	429
November	1st to 10th	Day	37% 14% 28% 18% 4	395
	11th to 20th	Day	28% 20% 27% 16% 9% 1	400
	21st to end	Day	36% 19% 26% 14% 4 1	274
December	1st to 10th	Day	34% 17% 26% 16% 8% 1	200
	11th to 20th	Day	39% 22% 22% 12% 5% 1	200
	21st to end	Day	34% 21% 25% 14% 5% 1	220
January	1st to 10th	Night	27% 21% 32% 18% 2	800
	11th to 20th	Night	28% 19% 33% 18% 3	800
	21st to end	Night	20% 16% 36% 23% 5%	880
February	1st to 10th	Night	23% 21% 33% 18% 4	781
	11th to 20th	Night	27% 20% 33% 17% 3	743
	21st to end	Night	26% 18% 31% 21% 3	628
March	1st to 10th	Night	27% 15% 35% 20% 3	760
	11th to 20th	Night	28% 18% 31% 18% 5% 1	760
	21st to end	Night	27% 16% 27% 22% 7% 1	836
April	1st to 10th	Night	34% 14% 27% 20% 5% 1	760
	11th to 20th	Night	28% 13% 29% 24% 7%	644
	21st to end	Night	30% 18% 27% 20% 5%	570
May	1st to 10th	Night	27% 11% 30% 23% 8% 1	570
	11th to 20th	Night	23% 11% 29% 31% 6%	403
	21st to end	Night	26% 7% 29% 30% 8%	411
June	1st to 10th	Night	30% 7% 23% 31% 8% 1	380
	11th to 20th	Night	22% 7% 23% 34% 13% 1	380
	21st to end	Night	21% 8% 31% 29% 11% 1	380
July	1st to 10th	Night	18% 8% 30% 32% 11% 1	370
	11th to 20th	Night	18% 4 24% 40% 14%	368
	21st to end	Night	18% 5% 23% 43% 11%	416
August	1st to 10th	Night	17% 5% 18% 40% 19%	421
	11th to 20th	Night	18% 6% 23% 35% 17% 1	562
	21st to end	Night	17% 8% 24% 33% 16% 2	717
September	1st to 10th	Night	20% 8% 27% 30% 13% 2	760
	11th to 20th	Night	23% 8% 20% 30% 17% 2	760
	21st to end	Night	23% 8% 27% 26% 15% 1	760
October	1st to 10th	Night	24% 10% 24% 30% 11%	760
	11th to 20th	Night	31% 12% 25% 22% 9% 1	760
	21st to end	Night	33% 14% 28% 19% 6%	836
November	1st to 10th	Night	31% 14% 25% 24% 6%	780
	11th to 20th	Night	28% 14% 28% 21% 9% 1	800
	21st to end	Night	31% 17% 28% 18% 5% 1	883
December	1st to 10th	Night	34% 16% 27% 17% 5%	900
	11th to 20th	Night	31% 20% 23% 19% 7%	900
	21st to end	Night	34% 19% 25% 17% 5% 1	955

Page generated at 2025-02-03 03:05:52. Version ac07

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