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 2024-01-16.

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	15% 10% 4 7% 7% 4 5% 5% 5% 7% 31%	74578
	Night	14% 10% 4 7% 6% 3 5% 5% 5% 7% 35%	75223
Transparency	Day	51% 9% 13% 17% 9% 1	74277
	Night	48% 9% 13% 18% 10% 1	75058
Seeing	Day	22% 19% 32% 20% 7% 1	14328
	Night	20% 14% 33% 25% 8% 1	22780

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	9% 14% 6% 9% 6% 4 5% 5% 5% 7% 31%	1455
	11th to 20th	Day	7% 11% 5% 11% 8% 5% 5% 5% 5% 6% 31%	1480
	21st to end	Day	6% 8% 4 8% 9% 4 6% 5% 6% 8% 35%	1584
February	1st to 10th	Day	4 10% 5% 9% 10% 6% 8% 6% 5% 8% 28%	1446
	11th to 20th	Day	7% 13% 4 11% 8% 5% 6% 5% 5% 7% 28%	1689
	21st to end	Day	8% 14% 4 8% 8% 5% 5% 5% 5% 6% 32%	1480
March	1st to 10th	Day	10% 15% 6% 8% 7% 3 5% 5% 4 7% 32%	1797
	11th to 20th	Day	11% 12% 5% 7% 6% 3 5% 6% 7% 6% 31%	1908
	21st to end	Day	11% 14% 6% 8% 6% 3 4 4 5% 5% 33%	2281
April	1st to 10th	Day	17% 15% 5% 7% 6% 4 4 4 6% 6% 25%	2160
	11th to 20th	Day	15% 12% 3 7% 6% 3 4 4 4 5% 36%	2258
	21st to end	Day	20% 13% 3 7% 5% 3 5% 4 4 6% 29%	2340
May	1st to 10th	Day	20% 10% 3 6% 5% 3 3 4 5% 7% 32%	2389
	11th to 20th	Day	18% 8% 3 6% 6% 4 6% 4 5% 6% 33%	2478
	21st to end	Day	18% 6% 3 5% 6% 4 6% 6% 6% 8% 32%	2871
June	1st to 10th	Day	22% 8% 3 5% 7% 4 6% 6% 6% 7% 27%	2700
	11th to 20th	Day	21% 8% 3 7% 6% 4 5% 4 5% 8% 31%	2700
	21st to end	Day	26% 7% 3 6% 6% 4 5% 5% 5% 6% 26%	2700
July	1st to 10th	Day	16% 7% 4 6% 7% 5% 6% 5% 7% 9% 28%	2696
	11th to 20th	Day	14% 7% 3 8% 7% 5% 8% 7% 6% 7% 29%	2520
	21st to end	Day	14% 7% 3 6% 7% 5% 7% 7% 7% 8% 29%	2744
August	1st to 10th	Day	16% 7% 4 7% 9% 5% 7% 7% 8% 8% 23%	2490
	11th to 20th	Day	16% 8% 3 7% 6% 5% 6% 7% 7% 8% 28%	2304
	21st to end	Day	12% 7% 2 7% 7% 4 6% 7% 7% 8% 33%	2520
September	1st to 10th	Day	15% 6% 3 7% 7% 4 5% 6% 5% 7% 36%	2160
	11th to 20th	Day	16% 6% 3 6% 6% 4 4 5% 5% 6% 41%	1983
	21st to end	Day	18% 8% 3 5% 5% 3 5% 5% 5% 7% 36%	1980
October	1st to 10th	Day	18% 9% 3 6% 6% 3 5% 6% 5% 7% 32%	1976
	11th to 20th	Day	19% 12% 4 8% 7% 3 5% 5% 5% 6% 25%	1638
	21st to end	Day	21% 12% 5% 6% 6% 3 6% 4 4 5% 28%	1782
November	1st to 10th	Day	15% 11% 5% 8% 7% 4 5% 5% 5% 7% 30%	1671
	11th to 20th	Day	16% 10% 5% 7% 7% 2 6% 6% 5% 7% 29%	1639
	21st to end	Day	14% 15% 5% 8% 5% 3 5% 5% 6% 8% 27%	1330
December	1st to 10th	Day	16% 13% 5% 11% 6% 3 5% 5% 6% 6% 25%	1330
	11th to 20th	Day	14% 11% 4 8% 8% 3 5% 5% 5% 5% 33%	1668
	21st to end	Day	15% 14% 5% 8% 4 2 3 4 4 5% 35%	2431
January	1st to 10th	Night	9% 12% 5% 9% 8% 4 6% 6% 6% 6% 29%	2705
	11th to 20th	Night	9% 10% 6% 11% 7% 3 5% 5% 5% 5% 34%	2602
	21st to end	Night	7% 8% 5% 9% 8% 5% 5% 5% 5% 7% 37%	2772
February	1st to 10th	Night	6% 8% 5% 9% 7% 4 5% 6% 7% 8% 35%	2513
	11th to 20th	Night	7% 12% 6% 11% 8% 4 5% 4 5% 7% 33%	2155
	21st to end	Night	9% 11% 3 8% 7% 4 5% 5% 6% 7% 34%	1776
March	1st to 10th	Night	10% 13% 6% 8% 5% 3 5% 6% 6% 6% 33%	2150
	11th to 20th	Night	11% 12% 6% 7% 6% 4 6% 4 5% 6% 33%	2051
	21st to end	Night	11% 12% 4 6% 5% 3 4 5% 5% 6% 37%	2071
April	1st to 10th	Night	16% 15% 5% 8% 5% 3 5% 4 4 5% 30%	1800
	11th to 20th	Night	15% 11% 2 6% 6% 3 4 5% 5% 9% 34%	1651
	21st to end	Night	19% 13% 3 6% 5% 2 4 3 4 5% 35%	1620
May	1st to 10th	Night	20% 9% 4 6% 5% 3 4 4 5% 5% 34%	1585
	11th to 20th	Night	19% 8% 3 6% 5% 3 5% 5% 5% 7% 34%	1415
	21st to end	Night	20% 6% 3 6% 4 3 5% 5% 4 7% 37%	1400
June	1st to 10th	Night	19% 9% 3 6% 6% 3 4 5% 7% 8% 31%	1260
	11th to 20th	Night	18% 5% 3 7% 5% 3 4 4 5% 7% 40%	1260
	21st to end	Night	20% 7% 3 6% 6% 4 5% 5% 5% 6% 32%	1260
July	1st to 10th	Night	19% 4 3 5% 3 2 4 5% 6% 10% 40%	1261
	11th to 20th	Night	11% 5% 3 6% 6% 3 5% 6% 8% 8% 38%	1440
	21st to end	Night	11% 6% 2 6% 5% 4 5% 6% 6% 9% 40%	1574
August	1st to 10th	Night	13% 5% 1 4 5% 3 5% 5% 7% 9% 43%	1432
	11th to 20th	Night	15% 6% 2 5% 5% 3 5% 6% 6% 9% 38%	1593
	21st to end	Night	14% 6% 2 4 4 3 5% 4 5% 10% 44%	1834
September	1st to 10th	Night	14% 6% 3 4 5% 3 4 5% 5% 6% 46%	1800
	11th to 20th	Night	16% 8% 2 5% 5% 3 5% 5% 5% 6% 41%	1976
	21st to end	Night	16% 7% 2 6% 5% 3 4 4 4 7% 42%	1980
October	1st to 10th	Night	15% 9% 3 5% 6% 3 5% 4 5% 6% 39%	1984
	11th to 20th	Night	20% 9% 3 7% 5% 2 5% 4 5% 8% 31%	2319
	21st to end	Night	20% 10% 3 6% 5% 3 4 5% 6% 8% 30%	2574
November	1st to 10th	Night	14% 9% 4 8% 6% 3 4 5% 6% 7% 34%	2407
	11th to 20th	Night	14% 10% 3 7% 6% 4 5% 5% 5% 8% 32%	2539
	21st to end	Night	13% 12% 4 8% 6% 3 5% 5% 6% 7% 31%	2847
December	1st to 10th	Night	12% 14% 6% 9% 7% 3 5% 4 5% 7% 29%	2850
	11th to 20th	Night	14% 12% 4 8% 6% 3 5% 5% 5% 6% 32%	3531
	21st to end	Night	14% 14% 6% 8% 6% 3 4 4 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	54% 8% 10% 18% 10%	1456
	11th to 20th	Day	54% 7% 10% 16% 11% 2	1480
	21st to end	Day	44% 9% 12% 15% 17% 2	1584
February	1st to 10th	Day	52% 9% 11% 14% 11% 3	1446
	11th to 20th	Day	55% 7% 11% 13% 11% 2	1697
	21st to end	Day	52% 7% 8% 17% 12% 4	1480
March	1st to 10th	Day	53% 6% 11% 13% 13% 4	1800
	11th to 20th	Day	51% 8% 11% 14% 13% 2	1908
	21st to end	Day	53% 6% 9% 17% 10% 4	2281
April	1st to 10th	Day	59% 6% 11% 11% 10% 3	2160
	11th to 20th	Day	50% 5% 12% 19% 11% 3	2258
	21st to end	Day	55% 7% 11% 14% 11% 2	2340
May	1st to 10th	Day	50% 7% 13% 15% 12% 2	2389
	11th to 20th	Day	51% 8% 11% 20% 10% 1	2482
	21st to end	Day	48% 10% 12% 20% 10%	2871
June	1st to 10th	Day	53% 10% 12% 18% 7% 1	2700
	11th to 20th	Day	51% 8% 13% 18% 9% 1	2700
	21st to end	Day	56% 9% 12% 15% 7%	2700
July	1st to 10th	Day	48% 12% 16% 18% 6%	2621
	11th to 20th	Day	50% 12% 14% 17% 7%	2445
	21st to end	Day	48% 15% 14% 17% 6%	2591
August	1st to 10th	Day	52% 15% 15% 15% 3	2476
	11th to 20th	Day	47% 13% 18% 15% 6%	2304
	21st to end	Day	42% 14% 18% 19% 7%	2520
September	1st to 10th	Day	44% 9% 17% 19% 11%	2160
	11th to 20th	Day	41% 9% 16% 23% 10% 1	1983
	21st to end	Day	45% 9% 14% 21% 11%	1980
October	1st to 10th	Day	48% 8% 15% 20% 9%	1976
	11th to 20th	Day	56% 10% 15% 15% 4	1638
	21st to end	Day	57% 9% 12% 15% 6% 1	1782
November	1st to 10th	Day	52% 9% 14% 17% 7% 1	1671
	11th to 20th	Day	54% 9% 13% 18% 7% 1	1639
	21st to end	Day	54% 10% 15% 13% 7%	1330
December	1st to 10th	Day	58% 8% 12% 14% 9%	1330
	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	54% 11% 11% 14% 9% 1	2705
	11th to 20th	Night	53% 9% 11% 15% 10% 2	2602
	21st to end	Night	47% 7% 10% 19% 15% 2	2772
February	1st to 10th	Night	45% 8% 12% 19% 13% 2	2513
	11th to 20th	Night	53% 7% 11% 13% 14% 1	2157
	21st to end	Night	49% 6% 12% 17% 13% 3	1776
March	1st to 10th	Night	51% 7% 11% 17% 12% 2	2160
	11th to 20th	Night	52% 7% 10% 16% 12% 2	2052
	21st to end	Night	47% 7% 12% 17% 13% 4	2071
April	1st to 10th	Night	56% 5% 10% 13% 13% 3	1800
	11th to 20th	Night	48% 7% 12% 19% 13% 1	1651
	21st to end	Night	53% 6% 8% 18% 12% 2	1620
May	1st to 10th	Night	52% 6% 12% 16% 12% 3	1585
	11th to 20th	Night	47% 7% 13% 20% 11% 1	1416
	21st to end	Night	46% 9% 12% 19% 13% 1	1401
June	1st to 10th	Night	49% 9% 14% 20% 7% 1	1260
	11th to 20th	Night	44% 6% 13% 22% 12% 3	1260
	21st to end	Night	52% 10% 13% 16% 10%	1260
July	1st to 10th	Night	41% 12% 19% 22% 6%	1226
	11th to 20th	Night	40% 14% 16% 23% 7%	1392
	21st to end	Night	41% 13% 17% 23% 7%	1486
August	1st to 10th	Night	35% 16% 20% 24% 5%	1422
	11th to 20th	Night	41% 14% 19% 18% 8%	1593
	21st to end	Night	38% 10% 17% 29% 6%	1834
September	1st to 10th	Night	37% 11% 16% 24% 11% 1	1800
	11th to 20th	Night	42% 10% 17% 23% 7% 1	1976
	21st to end	Night	42% 9% 13% 25% 10% 1	1980
October	1st to 10th	Night	43% 8% 15% 23% 11% 1	1984
	11th to 20th	Night	51% 9% 16% 18% 6%	2319
	21st to end	Night	50% 11% 14% 17% 8% 1	2574
November	1st to 10th	Night	47% 9% 16% 19% 8%	2407
	11th to 20th	Night	49% 8% 15% 17% 10% 2	2539
	21st to end	Night	53% 9% 13% 15% 9% 1	2847
December	1st to 10th	Night	57% 7% 11% 15% 8% 1	2850
	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	20% 22% 34% 16% 7% 1	170
	21st to end	Day	13% 25% 36% 16% 9% 1	176
February	1st to 10th	Day	16% 32% 39% 11% 3	166
	11th to 20th	Day	16% 24% 41% 14% 4 1	390
	21st to end	Day	17% 27% 34% 17% 4 1	346
March	1st to 10th	Day	22% 23% 31% 18% 5%	420
	11th to 20th	Day	20% 23% 32% 18% 7%	420
	21st to end	Day	23% 24% 27% 18% 8% 1	462
April	1st to 10th	Day	28% 25% 26% 17% 4	420
	11th to 20th	Day	24% 19% 32% 18% 6% 2	412
	21st to end	Day	27% 19% 35% 14% 3 2	420
May	1st to 10th	Day	30% 16% 30% 16% 7% 1	423
	11th to 20th	Day	21% 23% 30% 18% 6% 2	447
	21st to end	Day	21% 19% 34% 18% 6% 1	631
June	1st to 10th	Day	26% 15% 29% 22% 7% 1	630
	11th to 20th	Day	26% 17% 26% 19% 11% 1	630
	21st to end	Day	26% 12% 29% 23% 8% 1	630
July	1st to 10th	Day	17% 13% 33% 28% 9% 1	616
	11th to 20th	Day	17% 15% 36% 23% 9% 1	444
	21st to end	Day	14% 12% 39% 27% 7% 1	488
August	1st to 10th	Day	15% 15% 33% 24% 10% 2	446
	11th to 20th	Day	15% 12% 33% 26% 12% 2	439
	21st to end	Day	16% 20% 29% 20% 13% 2	495
September	1st to 10th	Day	17% 18% 31% 22% 8% 4	450
	11th to 20th	Day	23% 12% 33% 22% 6% 4	450
	21st to end	Day	22% 16% 28% 21% 8% 4	450
October	1st to 10th	Day	20% 19% 30% 21% 8% 3	448
	11th to 20th	Day	27% 18% 29% 15% 9% 2	360
	21st to end	Day	31% 17% 29% 19% 5% 1	396
November	1st to 10th	Day	24% 22% 30% 18% 4 1	365
	11th to 20th	Day	24% 17% 31% 19% 8% 1	370
	21st to end	Day	27% 27% 29% 15% 2 1	180
December	1st to 10th	Day	21% 19% 31% 18% 10% 1	180
	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	744
	21st to end	Night	12% 14% 37% 31% 6% 1	792
February	1st to 10th	Night	11% 15% 44% 24% 6%	720
	11th to 20th	Night	16% 18% 40% 20% 6%	703
	21st to end	Night	18% 15% 40% 22% 4 1	592
March	1st to 10th	Night	19% 17% 36% 23% 4	720
	11th to 20th	Night	19% 17% 38% 18% 7% 1	720
	21st to end	Night	19% 19% 32% 23% 6% 1	792
April	1st to 10th	Night	25% 17% 33% 20% 5%	720
	11th to 20th	Night	22% 14% 33% 22% 7%	587
	21st to end	Night	27% 13% 30% 23% 6%	540
May	1st to 10th	Night	27% 10% 32% 25% 6%	505
	11th to 20th	Night	24% 9% 31% 25% 11%	354
	21st to end	Night	24% 15% 30% 24% 6% 1	389
June	1st to 10th	Night	20% 8% 30% 30% 11% 1	360
	11th to 20th	Night	19% 7% 28% 32% 13% 1	360
	21st to end	Night	22% 6% 29% 32% 11%	360
July	1st to 10th	Night	20% 7% 31% 32% 9% 1	350
	11th to 20th	Night	14% 6% 25% 41% 13% 1	348
	21st to end	Night	16% 5% 25% 42% 12% 1	394
August	1st to 10th	Night	13% 6% 24% 41% 16% 1	358
	11th to 20th	Night	16% 6% 27% 34% 16% 1	529
	21st to end	Night	15% 8% 30% 31% 13% 2	646
September	1st to 10th	Night	16% 8% 32% 31% 11% 1	720
	11th to 20th	Night	21% 8% 29% 29% 11% 2	720
	21st to end	Night	19% 10% 31% 29% 10% 1	720
October	1st to 10th	Night	20% 13% 30% 28% 8% 2	720
	11th to 20th	Night	25% 11% 30% 24% 9% 1	720
	21st to end	Night	25% 15% 31% 22% 7%	792
November	1st to 10th	Night	22% 17% 31% 24% 5% 1	740
	11th to 20th	Night	22% 19% 30% 20% 7% 1	793
	21st to end	Night	21% 20% 30% 23% 5% 1	850
December	1st to 10th	Night	22% 16% 32% 23% 7% 1	850
	11th to 20th	Night	20% 19% 33% 21% 7%	850
	21st to end	Night	23% 15% 33% 21% 6% 1	935

Page generated at 2024-01-13 09:37:56. Version ac07

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