Charlevoix Regional County Municipality
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Charlevoix Regional County Municipality 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	14% 10% 3 8% 6% 5% 5% 4 6% 7% 31%	130872
	Night	12% 10% 4 9% 5% 5% 5% 4 6% 7% 34%	130676
Transparency	Day	49% 7% 14% 18% 10% 1	134308
	Night	48% 7% 14% 19% 11% 1	135327
Seeing	Day	22% 18% 32% 20% 7% 1	17119
	Night	19% 13% 33% 26% 8% 1	25579

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	8% 18% 5% 9% 5% 4 4 3 5% 8% 32%	4475
	11th to 20th	Day	5% 13% 5% 14% 7% 7% 6% 4 5% 6% 27%	4650
	21st to end	Day	3 5% 4 11% 9% 6% 6% 5% 7% 8% 38%	5124
February	1st to 10th	Day	4 10% 4 11% 10% 7% 7% 5% 5% 8% 31%	1688
	11th to 20th	Day	7% 14% 4 13% 6% 6% 5% 4 5% 7% 29%	1979
	21st to end	Day	7% 14% 3 9% 7% 5% 6% 4 7% 6% 33%	1730
March	1st to 10th	Day	12% 18% 5% 11% 6% 4 4 3 4 5% 28%	4576
	11th to 20th	Day	9% 17% 5% 9% 5% 4 5% 4 6% 6% 29%	4869
	21st to end	Day	11% 16% 5% 10% 6% 4 4 3 4 5% 33%	5735
April	1st to 10th	Day	16% 17% 4 8% 5% 5% 4 3 5% 6% 26%	2400
	11th to 20th	Day	14% 13% 3 8% 5% 4 4 3 4 5% 36%	2512
	21st to end	Day	19% 13% 3 7% 5% 4 5% 4 4 6% 30%	2600
May	1st to 10th	Day	20% 13% 4 7% 5% 4 4 4 5% 5% 28%	6019
	11th to 20th	Day	23% 8% 3 7% 5% 4 5% 4 5% 6% 29%	6318
	21st to end	Day	19% 9% 3 7% 6% 5% 5% 5% 6% 7% 29%	7333
June	1st to 10th	Day	22% 8% 3 6% 6% 5% 6% 4 6% 7% 27%	3000
	11th to 20th	Day	19% 8% 3 8% 5% 4 5% 3 6% 8% 31%	3000
	21st to end	Day	25% 8% 3 7% 5% 5% 5% 4 5% 6% 27%	3000
July	1st to 10th	Day	15% 7% 3 8% 6% 6% 6% 5% 7% 9% 27%	6788
	11th to 20th	Day	13% 6% 2 7% 5% 7% 7% 6% 7% 9% 31%	6360
	21st to end	Day	10% 5% 2 6% 5% 6% 7% 5% 7% 9% 39%	6926
August	1st to 10th	Day	13% 6% 2 7% 7% 6% 7% 6% 9% 8% 30%	4533
	11th to 20th	Day	17% 7% 3 8% 5% 6% 7% 5% 7% 8% 26%	4175
	21st to end	Day	17% 6% 2 7% 5% 5% 5% 4 6% 8% 35%	4562
September	1st to 10th	Day	14% 6% 2 7% 5% 5% 5% 4 5% 8% 37%	2400
	11th to 20th	Day	14% 6% 2 7% 4 4 5% 3 5% 6% 43%	2203
	21st to end	Day	18% 8% 3 6% 4 4 5% 4 6% 7% 36%	2200
October	1st to 10th	Day	17% 9% 2 7% 5% 4 5% 4 6% 7% 33%	2194
	11th to 20th	Day	19% 11% 3 9% 6% 5% 5% 4 5% 6% 27%	1820
	21st to end	Day	21% 12% 5% 6% 5% 4 4 4 5% 6% 28%	1980
November	1st to 10th	Day	14% 11% 5% 9% 5% 5% 4 4 5% 7% 30%	1851
	11th to 20th	Day	15% 12% 4 9% 5% 4 5% 4 5% 7% 30%	1811
	21st to end	Day	15% 16% 4 9% 4 5% 4 5% 6% 8% 25%	1470
December	1st to 10th	Day	11% 17% 5% 9% 4 4 4 4 6% 7% 30%	2350
	11th to 20th	Day	13% 9% 3 8% 7% 6% 5% 3 5% 6% 34%	2688
	21st to end	Day	13% 13% 4 10% 5% 3 4 3 4 5% 35%	3553
January	1st to 10th	Night	7% 15% 4 10% 7% 6% 5% 4 6% 6% 29%	8411
	11th to 20th	Night	5% 12% 6% 15% 8% 7% 6% 4 6% 7% 25%	8235
	21st to end	Night	3 5% 4 15% 7% 6% 5% 5% 6% 8% 37%	9057
February	1st to 10th	Night	5% 8% 4 10% 7% 5% 5% 5% 6% 8% 36%	2931
	11th to 20th	Night	6% 12% 6% 12% 6% 4 5% 3 5% 7% 33%	2525
	21st to end	Night	8% 11% 3 10% 6% 5% 5% 4 6% 7% 36%	2076
March	1st to 10th	Night	12% 16% 5% 11% 5% 5% 5% 6% 6% 5% 24%	5484
	11th to 20th	Night	8% 13% 4 10% 6% 6% 6% 4 6% 7% 28%	5245
	21st to end	Night	12% 15% 5% 9% 5% 5% 5% 3 5% 5% 32%	5193
April	1st to 10th	Night	15% 17% 4 9% 5% 4 4 3 4 5% 32%	2000
	11th to 20th	Night	15% 11% 3 8% 5% 4 5% 4 5% 8% 32%	1837
	21st to end	Night	19% 12% 2 7% 5% 4 4 3 4 5% 35%	1800
May	1st to 10th	Night	19% 11% 3 7% 4 4 4 3 5% 6% 33%	3963
	11th to 20th	Night	23% 9% 2 5% 4 4 4 3 5% 6% 34%	3575
	21st to end	Night	19% 8% 2 5% 3 4 4 4 6% 8% 37%	3542
June	1st to 10th	Night	18% 9% 2 6% 6% 5% 4 4 7% 7% 33%	1400
	11th to 20th	Night	17% 5% 3 7% 4 4 4 4 6% 7% 39%	1400
	21st to end	Night	20% 8% 3 6% 6% 6% 4 5% 5% 6% 32%	1400
July	1st to 10th	Night	12% 5% 2 6% 4 5% 5% 5% 8% 11% 37%	3174
	11th to 20th	Night	15% 7% 2 5% 4 4 4 4 7% 8% 40%	3600
	21st to end	Night	9% 4 2 5% 4 4 4 5% 6% 8% 49%	3926
August	1st to 10th	Night	13% 5% 2 6% 5% 4 4 4 7% 8% 41%	2586
	11th to 20th	Night	13% 6% 2 7% 5% 5% 5% 4 7% 8% 37%	2869
	21st to end	Night	17% 5% 2 5% 4 4 4 3 5% 8% 43%	3320
September	1st to 10th	Night	13% 7% 2 5% 3 4 4 3 5% 7% 47%	2000
	11th to 20th	Night	15% 7% 2 6% 4 4 4 4 6% 7% 43%	2196
	21st to end	Night	15% 7% 2 6% 5% 4 4 3 5% 7% 42%	2200
October	1st to 10th	Night	15% 9% 3 6% 4 5% 4 3 5% 7% 39%	2205
	11th to 20th	Night	19% 9% 3 8% 4 4 4 3 5% 7% 33%	2577
	21st to end	Night	19% 10% 2 7% 5% 5% 4 4 6% 8% 30%	2860
November	1st to 10th	Night	14% 10% 4 9% 5% 5% 4 4 6% 7% 33%	2667
	11th to 20th	Night	14% 11% 3 8% 5% 5% 5% 4 5% 7% 32%	2807
	21st to end	Night	13% 14% 4 9% 6% 5% 5% 4 6% 6% 28%	3147
December	1st to 10th	Night	9% 12% 5% 11% 6% 5% 5% 3 6% 7% 31%	5060
	11th to 20th	Night	15% 11% 3 8% 6% 6% 5% 4 5% 6% 31%	5741
	21st to end	Night	13% 13% 5% 10% 5% 4 4 3 4 5% 34%	7667

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	51% 6% 10% 21% 12%	4476
	11th to 20th	Day	53% 5% 11% 19% 12% 1	4680
	21st to end	Day	38% 8% 10% 19% 23% 1	5124
February	1st to 10th	Day	50% 8% 10% 16% 13% 3	1688
	11th to 20th	Day	54% 7% 11% 14% 12% 2	1987
	21st to end	Day	49% 8% 8% 19% 11% 4	1730
March	1st to 10th	Day	56% 7% 10% 10% 10% 7%	4579
	11th to 20th	Day	51% 8% 16% 14% 9% 1	4869
	21st to end	Day	54% 5% 6% 16% 14% 5%	5735
April	1st to 10th	Day	58% 6% 10% 12% 11% 3	2400
	11th to 20th	Day	50% 5% 12% 18% 11% 3	2512
	21st to end	Day	54% 7% 11% 14% 12% 2	2600
May	1st to 10th	Day	54% 6% 13% 14% 12% 1	6030
	11th to 20th	Day	53% 9% 14% 16% 6% 3	6322
	21st to end	Day	51% 8% 13% 16% 11%	7333
June	1st to 10th	Day	52% 10% 12% 19% 6% 1	3000
	11th to 20th	Day	50% 8% 14% 18% 9% 1	3000
	21st to end	Day	56% 9% 12% 15% 7% 1	3000
July	1st to 10th	Day	50% 6% 15% 21% 8%	6713
	11th to 20th	Day	46% 8% 17% 24% 5%	6285
	21st to end	Day	38% 8% 17% 27% 10%	6728
August	1st to 10th	Day	45% 10% 18% 18% 9%	4519
	11th to 20th	Day	51% 9% 20% 15% 4	4214
	21st to end	Day	44% 9% 19% 17% 11% 1	4562
September	1st to 10th	Day	43% 8% 17% 21% 11%	2400
	11th to 20th	Day	39% 8% 17% 25% 10% 1	2203
	21st to end	Day	45% 9% 14% 21% 11%	2200
October	1st to 10th	Day	53% 6% 13% 23% 6%	3571
	11th to 20th	Day	44% 6% 17% 25% 8%	2945
	21st to end	Day	44% 7% 19% 19% 11% 1	3180
November	1st to 10th	Day	51% 9% 14% 18% 7% 1	1851
	11th to 20th	Day	53% 8% 12% 19% 8% 1	1811
	21st to end	Day	56% 9% 14% 13% 8%	1470
December	1st to 10th	Day	51% 5% 13% 18% 13%	2350
	11th to 20th	Day	48% 7% 10% 17% 17% 1	2688
	21st to end	Day	50% 6% 10% 16% 14% 3	3553
January	1st to 10th	Night	53% 7% 13% 17% 9% 1	8411
	11th to 20th	Night	57% 6% 12% 16% 9% 1	8280
	21st to end	Night	42% 7% 10% 20% 20% 1	9057
February	1st to 10th	Night	44% 7% 12% 21% 14% 2	2931
	11th to 20th	Night	51% 7% 12% 14% 15% 2	2527
	21st to end	Night	47% 6% 11% 19% 14% 3	2076
March	1st to 10th	Night	57% 6% 9% 12% 13% 3	5494
	11th to 20th	Night	52% 8% 17% 12% 9% 2	5246
	21st to end	Night	53% 5% 9% 18% 13% 2	5193
April	1st to 10th	Night	54% 5% 10% 14% 14% 3	2000
	11th to 20th	Night	49% 7% 12% 19% 13% 1	1837
	21st to end	Night	52% 6% 9% 19% 12% 2	1800
May	1st to 10th	Night	50% 6% 13% 17% 13% 1	3969
	11th to 20th	Night	49% 7% 14% 20% 9% 1	3576
	21st to end	Night	44% 8% 15% 19% 12% 2	3543
June	1st to 10th	Night	48% 9% 14% 22% 7% 1	1400
	11th to 20th	Night	43% 6% 15% 22% 12% 3	1400
	21st to end	Night	52% 9% 13% 16% 10%	1400
July	1st to 10th	Night	38% 7% 24% 26% 5%	3139
	11th to 20th	Night	40% 7% 24% 25% 5%	3552
	21st to end	Night	31% 8% 24% 28% 9%	3809
August	1st to 10th	Night	40% 10% 20% 22% 8%	2576
	11th to 20th	Night	44% 11% 21% 16% 8% 1	2896
	21st to end	Night	40% 7% 16% 27% 9%	3320
September	1st to 10th	Night	36% 10% 16% 26% 12% 1	2000
	11th to 20th	Night	40% 10% 17% 25% 8% 1	2196
	21st to end	Night	41% 9% 13% 25% 11% 1	2200
October	1st to 10th	Night	45% 6% 14% 28% 7% 1	3608
	11th to 20th	Night	45% 6% 14% 26% 9%	4191
	21st to end	Night	41% 8% 20% 18% 12%	4610
November	1st to 10th	Night	47% 9% 16% 20% 8%	2667
	11th to 20th	Night	50% 7% 14% 18% 10% 1	2807
	21st to end	Night	54% 9% 12% 15% 9% 1	3147
December	1st to 10th	Night	51% 5% 13% 23% 8% 1	5060
	11th to 20th	Night	51% 6% 9% 19% 14% 1	5742
	21st to end	Night	52% 7% 10% 15% 13% 2	7667

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	15% 18% 41% 21% 5%	220
	11th to 20th	Day	22% 21% 34% 14% 8% 1	220
	21st to end	Day	12% 26% 34% 18% 9% 1	242
February	1st to 10th	Day	14% 29% 38% 12% 6% 1	228
	11th to 20th	Day	17% 23% 40% 16% 4	500
	21st to end	Day	16% 25% 37% 17% 4 1	446
March	1st to 10th	Day	25% 22% 31% 17% 4	540
	11th to 20th	Day	22% 23% 32% 17% 6%	528
	21st to end	Day	23% 26% 27% 17% 7% 1	550
April	1st to 10th	Day	30% 23% 27% 16% 4	500
	11th to 20th	Day	24% 20% 33% 17% 5% 2	492
	21st to end	Day	28% 19% 35% 14% 3 2	500
May	1st to 10th	Day	30% 16% 29% 17% 7% 1	503
	11th to 20th	Day	22% 22% 28% 19% 7% 2	527
	21st to end	Day	22% 19% 33% 19% 6% 1	736
June	1st to 10th	Day	26% 14% 29% 22% 8% 1	730
	11th to 20th	Day	24% 18% 27% 19% 10% 1	730
	21st to end	Day	26% 13% 31% 22% 7% 1	730
July	1st to 10th	Day	19% 13% 32% 27% 9% 1	714
	11th to 20th	Day	17% 15% 38% 22% 8% 1	524
	21st to end	Day	14% 13% 39% 26% 7% 1	576
August	1st to 10th	Day	14% 16% 33% 26% 9% 3	526
	11th to 20th	Day	15% 12% 32% 27% 11% 3	519
	21st to end	Day	18% 18% 28% 21% 13% 2	583
September	1st to 10th	Day	16% 18% 32% 21% 9% 3	530
	11th to 20th	Day	22% 11% 30% 24% 9% 5%	530
	21st to end	Day	23% 15% 27% 22% 9% 4	530
October	1st to 10th	Day	21% 18% 29% 21% 9% 2	526
	11th to 20th	Day	26% 18% 29% 17% 9% 1	420
	21st to end	Day	32% 17% 29% 18% 4	462
November	1st to 10th	Day	26% 21% 31% 18% 4 1	425
	11th to 20th	Day	24% 17% 32% 18% 7% 1	430
	21st to end	Day	30% 25% 28% 14% 2	220
December	1st to 10th	Day	20% 20% 34% 17% 10%	220
	11th to 20th	Day	25% 24% 34% 12% 3 2	220
	21st to end	Day	21% 26% 26% 20% 5% 2	242
January	1st to 10th	Night	17% 15% 41% 23% 4 1	873
	11th to 20th	Night	16% 15% 40% 22% 6% 1	840
	21st to end	Night	11% 13% 37% 31% 6%	924
February	1st to 10th	Night	10% 14% 43% 25% 7% 1	840
	11th to 20th	Night	16% 17% 41% 20% 6%	823
	21st to end	Night	17% 15% 39% 24% 4 1	692
March	1st to 10th	Night	20% 17% 35% 23% 4	840
	11th to 20th	Night	19% 16% 38% 21% 6% 1	829
	21st to end	Night	19% 19% 34% 23% 5% 1	880
April	1st to 10th	Night	26% 17% 33% 19% 5%	800
	11th to 20th	Night	23% 15% 34% 22% 7%	653
	21st to end	Night	27% 13% 32% 22% 5%	600
May	1st to 10th	Night	26% 11% 33% 25% 6%	561
	11th to 20th	Night	23% 9% 31% 26% 10%	394
	21st to end	Night	24% 14% 29% 26% 6% 1	433
June	1st to 10th	Night	20% 8% 31% 30% 11% 1	400
	11th to 20th	Night	19% 7% 29% 32% 13% 1	400
	21st to end	Night	21% 6% 32% 31% 10%	400
July	1st to 10th	Night	19% 7% 31% 34% 8% 1	390
	11th to 20th	Night	14% 6% 25% 42% 12% 1	388
	21st to end	Night	15% 4 26% 43% 11% 1	438
August	1st to 10th	Night	12% 6% 23% 42% 17% 1	398
	11th to 20th	Night	16% 5% 26% 35% 16% 1	589
	21st to end	Night	16% 8% 29% 32% 13% 1	718
September	1st to 10th	Night	16% 9% 31% 32% 11% 1	800
	11th to 20th	Night	19% 9% 27% 30% 13% 2	800
	21st to end	Night	18% 9% 30% 29% 12% 1	800
October	1st to 10th	Night	20% 12% 31% 28% 8% 2	800
	11th to 20th	Night	24% 11% 30% 26% 9% 1	800
	21st to end	Night	25% 15% 31% 23% 6%	880
November	1st to 10th	Night	23% 17% 31% 23% 4 1	820
	11th to 20th	Night	22% 18% 30% 21% 7% 1	881
	21st to end	Night	23% 19% 30% 23% 5% 1	950
December	1st to 10th	Night	21% 16% 32% 24% 7% 1	950
	11th to 20th	Night	20% 19% 33% 21% 7%	950
	21st to end	Night	23% 14% 34% 22% 6% 1	1045

Page generated at 2026-03-15 02:23:50. Version ac07

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