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 2024-12-06.

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	14% 10% 3 8% 6% 5% 5% 4 6% 7% 31%	101803
	Night	13% 10% 4 8% 5% 5% 5% 4 6% 7% 34%	97931
Transparency	Day	49% 9% 14% 18% 9% 1	105257
	Night	47% 8% 15% 19% 10% 1	102566
Seeing	Day	22% 19% 31% 20% 7% 1	15548
	Night	20% 13% 33% 26% 8% 1	23867

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% 15% 6% 10% 5% 4 4 4 6% 8% 30%	2407
	11th to 20th	Day	6% 10% 5% 13% 7% 8% 6% 4 5% 5% 30%	2520
	21st to end	Day	5% 7% 4 12% 10% 6% 6% 4 5% 6% 34%	2772
February	1st to 10th	Day	4 11% 4 11% 9% 7% 7% 5% 5% 8% 29%	1526
	11th to 20th	Day	7% 14% 4 13% 7% 6% 5% 4 5% 7% 28%	1785
	21st to end	Day	8% 14% 3 9% 7% 5% 5% 4 6% 6% 32%	1570
March	1st to 10th	Day	11% 16% 4 9% 5% 4 5% 3 5% 7% 31%	3116
	11th to 20th	Day	10% 21% 6% 9% 5% 4 5% 4 6% 5% 25%	3352
	21st to end	Day	9% 15% 5% 10% 6% 4 4 3 4 5% 35%	4001
April	1st to 10th	Day	16% 17% 4 8% 5% 5% 4 3 5% 6% 26%	2280
	11th to 20th	Day	14% 13% 3 8% 5% 4 4 3 4 5% 36%	2385
	21st to end	Day	19% 13% 3 7% 4 4 5% 4 4 6% 30%	2470
May	1st to 10th	Day	16% 12% 3 8% 6% 5% 4 5% 6% 6% 29%	4197
	11th to 20th	Day	18% 7% 3 7% 5% 5% 6% 4 7% 8% 31%	4398
	21st to end	Day	15% 7% 3 7% 6% 6% 6% 5% 7% 8% 30%	5109
June	1st to 10th	Day	22% 8% 3 6% 6% 6% 6% 4 6% 7% 27%	2850
	11th to 20th	Day	19% 8% 3 8% 5% 4 5% 3 6% 8% 31%	2850
	21st to end	Day	26% 8% 3 7% 5% 5% 5% 4 5% 6% 26%	2850
July	1st to 10th	Day	15% 7% 3 8% 7% 6% 6% 4 7% 8% 29%	4742
	11th to 20th	Day	13% 6% 2 8% 6% 7% 8% 5% 7% 8% 30%	4440
	21st to end	Day	12% 6% 2 6% 6% 6% 7% 5% 7% 8% 36%	4814
August	1st to 10th	Day	13% 6% 2 8% 7% 6% 7% 6% 9% 8% 29%	4394
	11th to 20th	Day	18% 8% 3 8% 5% 6% 7% 5% 7% 8% 25%	4045
	21st to end	Day	17% 6% 2 7% 5% 5% 5% 4 6% 8% 35%	4422
September	1st to 10th	Day	15% 6% 3 7% 5% 6% 5% 4 5% 8% 36%	2280
	11th to 20th	Day	15% 6% 2 7% 5% 4 5% 3 5% 6% 42%	2093
	21st to end	Day	18% 8% 3 6% 4 4 5% 4 6% 7% 35%	2090
October	1st to 10th	Day	18% 10% 2 7% 5% 5% 5% 4 6% 6% 32%	2085
	11th to 20th	Day	19% 12% 4 9% 6% 5% 5% 4 5% 6% 26%	1729
	21st to end	Day	20% 12% 5% 7% 5% 4 5% 4 4 6% 29%	1881
November	1st to 10th	Day	14% 11% 5% 9% 5% 5% 5% 4 5% 6% 30%	1761
	11th to 20th	Day	15% 12% 4 9% 5% 4 5% 5% 5% 7% 29%	1725
	21st to end	Day	15% 17% 4 8% 4 5% 4 4 6% 8% 25%	1400
December	1st to 10th	Day	15% 15% 4 12% 5% 4 5% 4 5% 5% 26%	1365
	11th to 20th	Day	14% 12% 3 9% 7% 4 5% 4 5% 5% 33%	1668
	21st to end	Day	15% 15% 5% 8% 4 3 3 3 4 5% 35%	2431
January	1st to 10th	Night	8% 13% 5% 11% 8% 7% 5% 5% 6% 6% 27%	4524
	11th to 20th	Night	6% 11% 5% 12% 6% 6% 5% 4 5% 6% 32%	4440
	21st to end	Night	5% 9% 5% 16% 7% 6% 6% 4 6% 6% 31%	4884
February	1st to 10th	Night	6% 9% 4 10% 7% 5% 5% 5% 6% 8% 35%	2653
	11th to 20th	Night	6% 12% 6% 12% 7% 5% 5% 3 5% 7% 32%	2279
	21st to end	Night	9% 11% 3 10% 7% 5% 5% 4 6% 7% 33%	1884
March	1st to 10th	Night	12% 18% 5% 9% 4 4 4 6% 5% 5% 27%	3724
	11th to 20th	Night	8% 16% 5% 12% 6% 7% 5% 4 5% 6% 26%	3607
	21st to end	Night	11% 13% 5% 9% 6% 5% 5% 4 6% 6% 33%	3627
April	1st to 10th	Night	15% 17% 4 9% 5% 4 4 3 4 5% 31%	1900
	11th to 20th	Night	16% 11% 3 8% 5% 4 4 3 5% 8% 33%	1744
	21st to end	Night	18% 13% 2 7% 5% 4 4 3 4 5% 35%	1710
May	1st to 10th	Night	18% 9% 3 7% 5% 5% 4 4 5% 7% 34%	2771
	11th to 20th	Night	17% 9% 3 6% 4 4 4 3 5% 7% 38%	2495
	21st to end	Night	17% 5% 2 5% 4 4 5% 4 7% 9% 37%	2471
June	1st to 10th	Night	18% 9% 2 6% 6% 5% 4 4 7% 7% 32%	1330
	11th to 20th	Night	17% 5% 3 7% 4 4 3 4 6% 8% 40%	1330
	21st to end	Night	20% 8% 3 7% 6% 5% 4 5% 5% 6% 31%	1330
July	1st to 10th	Night	14% 5% 2 6% 3 4 5% 5% 8% 10% 38%	2224
	11th to 20th	Night	14% 5% 2 5% 4 4 4 4 8% 9% 40%	2520
	21st to end	Night	10% 5% 2 4 4 4 4 4 6% 9% 48%	2739
August	1st to 10th	Night	14% 6% 2 7% 5% 5% 5% 4 7% 8% 39%	2506
	11th to 20th	Night	14% 6% 2 7% 5% 5% 5% 4 7% 8% 36%	2779
	21st to end	Night	17% 5% 2 5% 4 4 4 3 5% 8% 44%	3218
September	1st to 10th	Night	13% 7% 2 5% 3 4 4 3 5% 7% 46%	1900
	11th to 20th	Night	15% 7% 2 6% 4 4 4 4 5% 6% 42%	2086
	21st to end	Night	16% 7% 2 7% 5% 4 4 3 5% 6% 41%	2090
October	1st to 10th	Night	15% 9% 3 6% 5% 4 4 3 5% 7% 38%	2095
	11th to 20th	Night	19% 10% 3 8% 4 4 4 3 5% 7% 32%	2448
	21st to end	Night	19% 10% 2 7% 4 5% 4 4 6% 8% 31%	2717
November	1st to 10th	Night	14% 10% 3 9% 5% 4 4 4 6% 7% 34%	2537
	11th to 20th	Night	14% 11% 3 9% 5% 5% 5% 4 5% 7% 32%	2673
	21st to end	Night	13% 14% 4 9% 6% 5% 4 4 6% 6% 29%	2997
December	1st to 10th	Night	12% 15% 5% 10% 7% 4 5% 3 5% 6% 28%	2932
	11th to 20th	Night	14% 12% 4 9% 6% 4 4 4 6% 6% 31%	3531
	21st to end	Night	14% 14% 5% 9% 5% 4 4 3 3 5% 32%	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	50% 9% 15% 20% 7%	2408
	11th to 20th	Day	51% 8% 12% 17% 10% 1	2520
	21st to end	Day	44% 12% 11% 14% 17% 1	2772
February	1st to 10th	Day	52% 8% 11% 14% 12% 3	1526
	11th to 20th	Day	55% 8% 11% 13% 12% 2	1793
	21st to end	Day	50% 8% 9% 17% 11% 4	1570
March	1st to 10th	Day	51% 9% 13% 13% 10% 4	3119
	11th to 20th	Day	56% 10% 13% 12% 8% 1	3352
	21st to end	Day	51% 6% 8% 17% 12% 5%	4001
April	1st to 10th	Day	58% 6% 10% 12% 10% 4	2280
	11th to 20th	Day	50% 6% 12% 18% 11% 3	2385
	21st to end	Day	54% 7% 11% 14% 12% 3	2470
May	1st to 10th	Day	49% 9% 15% 15% 11% 1	4211
	11th to 20th	Day	47% 11% 17% 18% 6%	4402
	21st to end	Day	47% 11% 14% 17% 12%	5109
June	1st to 10th	Day	53% 10% 12% 18% 6% 1	2850
	11th to 20th	Day	49% 8% 14% 18% 9% 1	2850
	21st to end	Day	56% 9% 12% 15% 7%	2850
July	1st to 10th	Day	49% 8% 15% 20% 8%	4667
	11th to 20th	Day	47% 9% 17% 22% 5%	4365
	21st to end	Day	41% 10% 17% 23% 8%	4661
August	1st to 10th	Day	46% 10% 18% 18% 8%	4380
	11th to 20th	Day	52% 9% 21% 14% 4	4084
	21st to end	Day	43% 9% 18% 17% 11% 1	4422
September	1st to 10th	Day	44% 8% 16% 20% 11%	2280
	11th to 20th	Day	40% 9% 17% 24% 10% 1	2093
	21st to end	Day	46% 9% 14% 21% 11%	2090
October	1st to 10th	Day	54% 6% 13% 22% 6%	3462
	11th to 20th	Day	45% 6% 16% 25% 8%	2854
	21st to end	Day	43% 7% 20% 18% 11% 1	3081
November	1st to 10th	Day	51% 9% 14% 18% 7% 1	1761
	11th to 20th	Day	53% 8% 12% 18% 7% 1	1725
	21st to end	Day	56% 9% 14% 13% 7%	1400
December	1st to 10th	Day	58% 8% 12% 14% 8%	1365
	11th to 20th	Day	54% 8% 8% 17% 13% 1	1668
	21st to end	Day	52% 7% 12% 16% 9% 4	2431
January	1st to 10th	Night	53% 11% 12% 13% 9% 1	4524
	11th to 20th	Night	50% 9% 14% 17% 9% 1	4440
	21st to end	Night	48% 11% 10% 16% 13% 2	4884
February	1st to 10th	Night	45% 8% 13% 19% 13% 2	2653
	11th to 20th	Night	52% 7% 12% 14% 14% 1	2281
	21st to end	Night	49% 6% 12% 18% 13% 3	1884
March	1st to 10th	Night	54% 8% 11% 15% 9% 3	3734
	11th to 20th	Night	57% 10% 13% 12% 7% 1	3608
	21st to end	Night	51% 7% 11% 18% 11% 2	3627
April	1st to 10th	Night	55% 5% 10% 14% 14% 3	1900
	11th to 20th	Night	49% 7% 12% 18% 13% 1	1744
	21st to end	Night	52% 7% 9% 19% 12% 2	1710
May	1st to 10th	Night	47% 8% 14% 18% 12% 2	2777
	11th to 20th	Night	45% 9% 17% 19% 10% 1	2496
	21st to end	Night	40% 10% 16% 20% 13% 1	2472
June	1st to 10th	Night	48% 9% 14% 21% 6% 1	1330
	11th to 20th	Night	42% 6% 15% 22% 12% 3	1330
	21st to end	Night	53% 9% 13% 16% 10%	1330
July	1st to 10th	Night	39% 9% 23% 26% 4	2189
	11th to 20th	Night	38% 8% 24% 25% 4	2472
	21st to end	Night	32% 9% 26% 23% 11%	2651
August	1st to 10th	Night	41% 10% 20% 22% 7%	2496
	11th to 20th	Night	45% 11% 21% 15% 8%	2806
	21st to end	Night	40% 7% 16% 27% 9%	3218
September	1st to 10th	Night	37% 10% 16% 24% 12% 1	1900
	11th to 20th	Night	41% 10% 17% 24% 7% 1	2086
	21st to end	Night	43% 9% 13% 25% 10% 1	2090
October	1st to 10th	Night	46% 6% 13% 27% 7%	3498
	11th to 20th	Night	45% 6% 14% 25% 9%	4062
	21st to end	Night	41% 8% 21% 18% 13%	4467
November	1st to 10th	Night	47% 9% 16% 20% 8%	2537
	11th to 20th	Night	49% 8% 15% 17% 10% 1	2673
	21st to end	Night	54% 9% 12% 15% 9% 1	2997
December	1st to 10th	Night	57% 7% 12% 15% 8% 1	2932
	11th to 20th	Night	52% 7% 13% 14% 12% 1	3532
	21st to end	Night	54% 9% 11% 13% 10% 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	14% 19% 42% 21% 4	180
	11th to 20th	Day	19% 23% 34% 16% 7% 1	180
	21st to end	Day	12% 25% 36% 18% 8% 2	198
February	1st to 10th	Day	16% 31% 38% 12% 3	186
	11th to 20th	Day	15% 25% 42% 14% 4	426
	21st to end	Day	17% 27% 35% 16% 4 1	382
March	1st to 10th	Day	23% 23% 31% 18% 5%	460
	11th to 20th	Day	20% 23% 31% 18% 7%	460
	21st to end	Day	23% 26% 27% 17% 7% 1	506
April	1st to 10th	Day	28% 23% 27% 17% 4	460
	11th to 20th	Day	24% 20% 31% 17% 5% 2	452
	21st to end	Day	27% 20% 35% 13% 3 2	460
May	1st to 10th	Day	29% 16% 30% 17% 7% 1	463
	11th to 20th	Day	21% 23% 29% 19% 7% 2	487
	21st to end	Day	21% 20% 34% 18% 6% 1	684
June	1st to 10th	Day	26% 15% 29% 22% 8% 1	680
	11th to 20th	Day	24% 17% 26% 20% 11% 1	680
	21st to end	Day	27% 13% 30% 22% 7% 1	680
July	1st to 10th	Day	18% 13% 32% 27% 9% 1	665
	11th to 20th	Day	17% 15% 37% 23% 8% 1	484
	21st to end	Day	14% 12% 38% 27% 8% 1	532
August	1st to 10th	Day	15% 16% 33% 24% 9% 2	486
	11th to 20th	Day	15% 11% 33% 27% 11% 3	479
	21st to end	Day	17% 18% 28% 20% 14% 2	539
September	1st to 10th	Day	17% 18% 32% 22% 9% 3	490
	11th to 20th	Day	22% 11% 31% 24% 8% 4	490
	21st to end	Day	23% 15% 27% 22% 8% 4	490
October	1st to 10th	Day	21% 18% 29% 21% 8% 3	487
	11th to 20th	Day	28% 18% 28% 15% 8% 2	390
	21st to end	Day	31% 17% 29% 18% 4	429
November	1st to 10th	Day	26% 21% 30% 19% 4 1	395
	11th to 20th	Day	25% 16% 33% 18% 7% 1	400
	21st to end	Day	30% 25% 29% 14% 2 1	200
December	1st to 10th	Day	20% 18% 31% 19% 11% 1	190
	11th to 20th	Day	25% 23% 37% 11% 2 2	180
	21st to end	Day	23% 27% 24% 21% 3 2	198
January	1st to 10th	Night	16% 15% 42% 23% 4 1	787
	11th to 20th	Night	16% 16% 41% 22% 5% 1	760
	21st to end	Night	11% 13% 37% 32% 6%	836
February	1st to 10th	Night	11% 14% 44% 24% 6%	760
	11th to 20th	Night	15% 17% 42% 20% 6%	743
	21st to end	Night	18% 16% 40% 22% 4 1	628
March	1st to 10th	Night	20% 17% 35% 24% 4	760
	11th to 20th	Night	18% 17% 38% 20% 6% 1	760
	21st to end	Night	19% 19% 33% 22% 5% 1	836
April	1st to 10th	Night	25% 16% 33% 20% 5%	760
	11th to 20th	Night	23% 15% 33% 22% 7%	620
	21st to end	Night	27% 13% 31% 23% 6%	570
May	1st to 10th	Night	26% 11% 32% 25% 6%	533
	11th to 20th	Night	23% 10% 30% 26% 10%	374
	21st to end	Night	24% 15% 30% 25% 6% 1	411
June	1st to 10th	Night	19% 8% 30% 30% 12% 1	380
	11th to 20th	Night	18% 7% 28% 32% 13% 1	380
	21st to end	Night	22% 6% 31% 31% 11%	380
July	1st to 10th	Night	19% 7% 31% 33% 9% 1	370
	11th to 20th	Night	14% 6% 25% 42% 12% 1	368
	21st to end	Night	15% 4 25% 43% 11% 1	416
August	1st to 10th	Night	12% 6% 24% 41% 16% 1	378
	11th to 20th	Night	16% 6% 26% 34% 16% 1	559
	21st to end	Night	16% 8% 29% 32% 14% 1	682
September	1st to 10th	Night	16% 9% 32% 32% 11% 1	760
	11th to 20th	Night	20% 8% 28% 30% 12% 2	760
	21st to end	Night	19% 9% 30% 29% 12% 1	760
October	1st to 10th	Night	20% 12% 30% 28% 9% 2	760
	11th to 20th	Night	26% 11% 30% 24% 9% 1	760
	21st to end	Night	25% 15% 31% 22% 6%	836
November	1st to 10th	Night	23% 17% 32% 23% 4 1	780
	11th to 20th	Night	22% 19% 30% 21% 7% 1	837
	21st to end	Night	23% 19% 30% 22% 5% 1	900
December	1st to 10th	Night	21% 16% 32% 23% 7% 1	878
	11th to 20th	Night	20% 19% 33% 21% 7%	850
	21st to end	Night	23% 15% 33% 21% 6% 1	935

Page generated at 2024-12-03 06:45:11. Version ac07

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