Miscou Island
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Miscou Island clear sky chart from 2005-11-06 to 2026-06-01.

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	16% 9% 3 8% 5% 4 5% 4 5% 6% 35%	132215
	Night	17% 11% 4 9% 5% 5% 4 3 5% 6% 31%	131154
Transparency	Day	48% 6% 14% 21% 9% 1	135694
	Night	53% 6% 12% 19% 9% 1	135753
Seeing	Day	21% 10% 28% 27% 12% 2	18747
	Night	23% 11% 28% 27% 10% 1	26321

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	16% 18% 6% 10% 5% 7% 4 4 5% 5% 20%	4093
	11th to 20th	Day	14% 14% 6% 14% 6% 5% 5% 4 6% 6% 19%	4084
	21st to end	Day	4 8% 4 11% 7% 7% 10% 5% 6% 7% 30%	5496
February	1st to 10th	Day	10% 13% 4 9% 7% 5% 4 4 6% 4 33%	1890
	11th to 20th	Day	13% 14% 4 9% 6% 5% 4 3 5% 5% 33%	1843
	21st to end	Day	10% 11% 4 7% 6% 5% 4 4 5% 5% 38%	1557
March	1st to 10th	Day	17% 12% 3 8% 4 4 5% 3 5% 6% 32%	4916
	11th to 20th	Day	15% 14% 4 10% 6% 5% 5% 3 5% 6% 27%	5090
	21st to end	Day	23% 12% 3 8% 5% 4 4 3 4 6% 29%	5587
April	1st to 10th	Day	20% 11% 3 6% 3 3 3 4 5% 5% 36%	2510
	11th to 20th	Day	19% 9% 2 6% 4 4 4 4 5% 6% 37%	2676
	21st to end	Day	23% 9% 3 7% 4 4 3 3 5% 6% 34%	2730
May	1st to 10th	Day	20% 10% 4 8% 5% 4 5% 3 5% 6% 31%	6361
	11th to 20th	Day	22% 10% 3 7% 3 4 4 3 5% 6% 34%	6458
	21st to end	Day	20% 8% 2 6% 4 4 4 3 5% 7% 36%	7328
June	1st to 10th	Day	24% 8% 2 7% 4 4 4 3 5% 6% 32%	3000
	11th to 20th	Day	17% 8% 2 6% 5% 4 4 3 5% 8% 39%	3000
	21st to end	Day	24% 8% 3 6% 4 4 4 4 6% 6% 32%	3000
July	1st to 10th	Day	11% 6% 3 7% 5% 5% 5% 5% 7% 9% 37%	6820
	11th to 20th	Day	10% 6% 2 6% 4 5% 5% 4 6% 7% 43%	6820
	21st to end	Day	12% 5% 2 5% 3 3 4 4 5% 8% 48%	7069
August	1st to 10th	Day	13% 6% 2 6% 4 4 5% 4 6% 8% 41%	4283
	11th to 20th	Day	13% 5% 2 5% 5% 5% 4 4 6% 8% 44%	4175
	21st to end	Day	13% 5% 2 5% 3 3 4 3 6% 8% 48%	4611
September	1st to 10th	Day	16% 6% 2 6% 4 4 4 3 6% 5% 44%	2400
	11th to 20th	Day	16% 7% 3 6% 3 3 4 3 4 5% 47%	2310
	21st to end	Day	18% 6% 2 5% 4 3 4 3 5% 7% 44%	2149
October	1st to 10th	Day	16% 7% 3 6% 4 4 4 3 5% 6% 42%	2000
	11th to 20th	Day	18% 9% 3 7% 4 4 4 4 5% 7% 35%	2000
	21st to end	Day	22% 10% 2 7% 4 3 4 3 5% 7% 34%	2081
November	1st to 10th	Day	20% 10% 3 6% 5% 5% 4 3 5% 6% 33%	1645
	11th to 20th	Day	21% 12% 4 8% 5% 5% 5% 4 6% 5% 26%	1680
	21st to end	Day	19% 15% 5% 10% 6% 5% 4 4 5% 5% 23%	1680
December	1st to 10th	Day	15% 14% 6% 12% 7% 6% 5% 3 5% 5% 23%	2632
	11th to 20th	Day	19% 11% 5% 13% 6% 4 4 3 4 5% 26%	2688
	21st to end	Day	17% 12% 6% 12% 5% 5% 4 3 4 6% 27%	3553
January	1st to 10th	Night	17% 18% 5% 11% 6% 6% 5% 3 5% 5% 19%	8831
	11th to 20th	Night	16% 14% 6% 13% 7% 5% 5% 3 5% 5% 20%	8831
	21st to end	Night	5% 10% 5% 9% 7% 7% 8% 4 6% 6% 32%	8689
February	1st to 10th	Night	12% 14% 4 9% 6% 5% 4 4 5% 5% 31%	2730
	11th to 20th	Night	15% 13% 4 8% 5% 5% 4 3 4 5% 33%	2663
	21st to end	Night	13% 11% 4 7% 6% 5% 4 4 5% 5% 35%	2249
March	1st to 10th	Night	18% 11% 3 9% 5% 6% 4 3 4 5% 29%	5125
	11th to 20th	Night	22% 15% 4 11% 5% 4 4 3 4 5% 23%	5089
	21st to end	Night	25% 13% 4 8% 5% 3 3 2 3 5% 28%	5587
April	1st to 10th	Night	22% 11% 4 7% 5% 5% 4 3 5% 5% 29%	2109
	11th to 20th	Night	21% 9% 3 6% 3 3 4 3 5% 7% 34%	1891
	21st to end	Night	23% 10% 3 7% 4 4 3 3 3 5% 35%	1890
May	1st to 10th	Night	20% 11% 4 8% 5% 4 4 3 4 5% 31%	3813
	11th to 20th	Night	23% 7% 3 6% 4 4 5% 3 4 5% 36%	3676
	21st to end	Night	18% 8% 3 7% 5% 5% 5% 3 6% 7% 33%	3853
June	1st to 10th	Night	26% 9% 3 7% 4 4 3 4 4 7% 30%	1400
	11th to 20th	Night	19% 8% 2 5% 4 5% 3 4 7% 7% 38%	1400
	21st to end	Night	24% 9% 3 6% 5% 4 5% 5% 6% 5% 29%	1400
July	1st to 10th	Night	16% 7% 3 6% 5% 5% 5% 5% 7% 8% 33%	3160
	11th to 20th	Night	11% 6% 2 7% 5% 5% 6% 4 7% 9% 38%	3160
	21st to end	Night	10% 6% 2 6% 5% 5% 5% 4 7% 7% 44%	3757
August	1st to 10th	Night	14% 8% 3 9% 6% 5% 5% 5% 5% 7% 33%	2865
	11th to 20th	Night	11% 8% 2 6% 5% 4 5% 4 6% 7% 41%	2872
	21st to end	Night	13% 4 2 6% 3 4 5% 3 6% 7% 47%	3286
September	1st to 10th	Night	18% 6% 2 5% 3 4 3 3 5% 7% 44%	2000
	11th to 20th	Night	17% 5% 2 5% 4 3 4 2 5% 6% 48%	2089
	21st to end	Night	17% 5% 2 5% 3 2 4 3 5% 6% 47%	2250
October	1st to 10th	Night	17% 7% 2 6% 4 4 4 4 5% 6% 42%	2400
	11th to 20th	Night	19% 8% 3 6% 4 4 4 3 5% 6% 37%	2400
	21st to end	Night	22% 10% 3 8% 4 4 4 3 4 5% 33%	2755
November	1st to 10th	Night	20% 9% 3 7% 4 4 4 3 5% 6% 33%	2873
	11th to 20th	Night	22% 13% 4 8% 5% 4 5% 4 5% 6% 25%	2940
	21st to end	Night	23% 14% 5% 9% 5% 5% 3 3 5% 6% 23%	2940
December	1st to 10th	Night	15% 12% 7% 11% 7% 5% 4 4 5% 5% 25%	4773
	11th to 20th	Night	20% 11% 4 10% 6% 4 4 3 4 5% 28%	5741
	21st to end	Night	18% 14% 5% 12% 6% 5% 4 3 4 6% 24%	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	64% 7% 11% 11% 7%	4094
	11th to 20th	Day	63% 12% 9% 8% 8%	4110
	21st to end	Day	49% 8% 12% 21% 9%	5496
February	1st to 10th	Day	50% 6% 13% 18% 11% 2	1890
	11th to 20th	Day	53% 5% 10% 20% 11% 1	1851
	21st to end	Day	45% 6% 9% 24% 13% 3	1557
March	1st to 10th	Day	51% 7% 12% 18% 12% 1	4920
	11th to 20th	Day	58% 6% 11% 14% 8% 3	5090
	21st to end	Day	57% 4 6% 21% 11% 1	5587
April	1st to 10th	Day	49% 5% 9% 19% 16% 2	2510
	11th to 20th	Day	47% 5% 11% 23% 13% 1	2676
	21st to end	Day	51% 5% 10% 16% 15% 3	2730
May	1st to 10th	Day	53% 6% 11% 21% 9%	6373
	11th to 20th	Day	51% 5% 15% 23% 7% 1	6462
	21st to end	Day	46% 7% 14% 22% 10% 1	7328
June	1st to 10th	Day	52% 6% 12% 20% 10%	3000
	11th to 20th	Day	44% 6% 14% 24% 12% 1	3000
	21st to end	Day	52% 6% 13% 19% 8% 1	3000
July	1st to 10th	Day	42% 6% 19% 23% 9%	6745
	11th to 20th	Day	38% 7% 20% 27% 8%	6739
	21st to end	Day	35% 6% 22% 28% 9%	6868
August	1st to 10th	Day	40% 7% 19% 24% 10%	4269
	11th to 20th	Day	38% 7% 20% 24% 10% 1	4214
	21st to end	Day	35% 5% 19% 28% 13% 1	4611
September	1st to 10th	Day	40% 7% 16% 27% 11%	2400
	11th to 20th	Day	40% 6% 16% 26% 12%	2310
	21st to end	Day	40% 6% 13% 28% 12% 1	2149
October	1st to 10th	Day	43% 5% 15% 27% 8% 1	3260
	11th to 20th	Day	49% 6% 15% 23% 7%	3240
	21st to end	Day	42% 6% 17% 24% 11%	3337
November	1st to 10th	Day	53% 7% 13% 20% 8% 1	1645
	11th to 20th	Day	57% 8% 13% 14% 8%	1680
	21st to end	Day	63% 7% 13% 12% 5%	1680
December	1st to 10th	Day	61% 9% 11% 15% 4	2632
	11th to 20th	Day	60% 6% 12% 15% 6%	2688
	21st to end	Day	58% 6% 11% 18% 6% 1	3553
January	1st to 10th	Night	65% 7% 14% 12% 2	8831
	11th to 20th	Night	63% 8% 11% 13% 5%	8880
	21st to end	Night	49% 7% 14% 20% 10% 1	8689
February	1st to 10th	Night	53% 5% 10% 16% 13% 2	2730
	11th to 20th	Night	55% 4 11% 18% 12% 1	2666
	21st to end	Night	49% 5% 9% 22% 14% 2	2249
March	1st to 10th	Night	56% 6% 8% 15% 14% 2	5134
	11th to 20th	Night	64% 5% 8% 13% 9% 2	5090
	21st to end	Night	60% 4 6% 14% 14% 2	5587
April	1st to 10th	Night	57% 5% 8% 14% 14% 2	2109
	11th to 20th	Night	50% 4 10% 21% 14% 2	1891
	21st to end	Night	53% 5% 8% 16% 17% 2	1890
May	1st to 10th	Night	56% 5% 7% 18% 11% 2	3818
	11th to 20th	Night	49% 6% 11% 23% 10% 1	3677
	21st to end	Night	50% 7% 12% 21% 10% 1	3854
June	1st to 10th	Night	55% 4 11% 21% 8%	1400
	11th to 20th	Night	45% 6% 12% 22% 12% 2	1400
	21st to end	Night	56% 8% 12% 15% 9% 1	1400
July	1st to 10th	Night	47% 7% 16% 21% 9%	3125
	11th to 20th	Night	42% 6% 19% 29% 4	3118
	21st to end	Night	38% 7% 21% 25% 8%	3644
August	1st to 10th	Night	50% 9% 14% 20% 8%	2854
	11th to 20th	Night	41% 7% 17% 26% 9%	2899
	21st to end	Night	35% 5% 19% 27% 13%	3285
September	1st to 10th	Night	41% 6% 14% 29% 9% 1	2000
	11th to 20th	Night	37% 6% 15% 28% 12% 1	2089
	21st to end	Night	37% 6% 13% 27% 15% 1	2250
October	1st to 10th	Night	46% 5% 13% 28% 8% 1	3920
	11th to 20th	Night	41% 5% 12% 31% 10%	3899
	21st to end	Night	47% 5% 14% 22% 11%	4440
November	1st to 10th	Night	52% 5% 14% 20% 8% 1	2873
	11th to 20th	Night	59% 7% 13% 14% 7%	2940
	21st to end	Night	63% 7% 14% 12% 5%	2940
December	1st to 10th	Night	57% 9% 12% 18% 5%	4773
	11th to 20th	Night	59% 5% 9% 20% 6% 1	5742
	21st to end	Night	60% 7% 12% 15% 5%	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	28% 14% 34% 18% 7%	220
	11th to 20th	Day	30% 17% 26% 16% 9% 1	220
	21st to end	Day	12% 14% 36% 26% 10% 1	416
February	1st to 10th	Day	19% 13% 32% 24% 8% 2	430
	11th to 20th	Day	19% 14% 37% 21% 8% 1	426
	21st to end	Day	17% 12% 34% 28% 8% 1	355
March	1st to 10th	Day	20% 13% 35% 25% 5% 2	527
	11th to 20th	Day	19% 13% 30% 24% 11% 2	540
	21st to end	Day	23% 12% 32% 24% 6% 3	594
April	1st to 10th	Day	28% 16% 29% 21% 6%	540
	11th to 20th	Day	24% 10% 33% 23% 9% 2	532
	21st to end	Day	26% 9% 26% 25% 11% 2	540
May	1st to 10th	Day	27% 7% 28% 25% 11% 2	694
	11th to 20th	Day	22% 8% 26% 24% 18% 3	774
	21st to end	Day	23% 7% 29% 29% 10% 2	845
June	1st to 10th	Day	27% 5% 25% 29% 12% 3	730
	11th to 20th	Day	18% 5% 24% 33% 16% 2	730
	21st to end	Day	25% 5% 23% 30% 13% 2	730
July	1st to 10th	Day	18% 4 26% 34% 15% 4	720
	11th to 20th	Day	14% 4 23% 38% 18% 3	718
	21st to end	Day	18% 5% 20% 34% 19% 4	795
August	1st to 10th	Day	11% 6% 22% 35% 23% 3	561
	11th to 20th	Day	15% 4 20% 35% 21% 4	519
	21st to end	Day	14% 6% 22% 35% 19% 5%	583
September	1st to 10th	Day	16% 6% 29% 32% 14% 2	530
	11th to 20th	Day	19% 8% 26% 32% 13% 3	530
	21st to end	Day	19% 9% 33% 24% 12% 3	501
October	1st to 10th	Day	16% 8% 30% 29% 14% 2	420
	11th to 20th	Day	24% 11% 31% 19% 13% 2	420
	21st to end	Day	26% 13% 32% 20% 7% 1	462
November	1st to 10th	Day	23% 16% 33% 21% 6% 1	425
	11th to 20th	Day	29% 16% 28% 20% 7% 2	430
	21st to end	Day	28% 17% 33% 17% 5% 1	430
December	1st to 10th	Day	25% 16% 33% 19% 6% 1	398
	11th to 20th	Day	24% 25% 29% 19% 4	220
	21st to end	Day	20% 21% 33% 19% 7%	242
January	1st to 10th	Night	25% 13% 34% 20% 6% 1	950
	11th to 20th	Night	22% 13% 33% 24% 7%	950
	21st to end	Night	19% 13% 36% 22% 9% 1	951
February	1st to 10th	Night	18% 12% 36% 24% 8% 2	840
	11th to 20th	Night	23% 12% 33% 24% 6% 2	823
	21st to end	Night	20% 9% 33% 27% 11% 1	692
March	1st to 10th	Night	20% 11% 34% 28% 6% 1	840
	11th to 20th	Night	21% 10% 32% 27% 9% 1	840
	21st to end	Night	22% 11% 29% 28% 8% 1	924
April	1st to 10th	Night	26% 11% 28% 27% 8%	639
	11th to 20th	Night	24% 6% 32% 27% 10% 1	624
	21st to end	Night	25% 10% 24% 27% 11% 2	630
May	1st to 10th	Night	27% 6% 22% 29% 13% 3	630
	11th to 20th	Night	22% 5% 24% 30% 16% 3	622
	21st to end	Night	20% 7% 29% 32% 11% 1	603
June	1st to 10th	Night	28% 4 20% 33% 14% 1	400
	11th to 20th	Night	22% 4 22% 30% 20% 3	400
	21st to end	Night	26% 4 17% 37% 14% 2	400
July	1st to 10th	Night	18% 4 18% 37% 20% 3	390
	11th to 20th	Night	15% 5% 18% 43% 18% 2	388
	21st to end	Night	17% 4 20% 38% 18% 2	569
August	1st to 10th	Night	17% 3 17% 41% 20% 2	598
	11th to 20th	Night	17% 3 16% 41% 21% 2	592
	21st to end	Night	14% 4 20% 36% 23% 4	660
September	1st to 10th	Night	21% 6% 25% 34% 13% 2	600
	11th to 20th	Night	18% 8% 21% 36% 16% 1	689
	21st to end	Night	20% 7% 29% 30% 13% 1	800
October	1st to 10th	Night	19% 8% 32% 29% 11% 1	800
	11th to 20th	Night	22% 11% 29% 25% 11% 2	800
	21st to end	Night	26% 15% 28% 23% 7% 1	902
November	1st to 10th	Night	26% 17% 30% 20% 6% 1	930
	11th to 20th	Night	28% 16% 29% 19% 6% 2	950
	21st to end	Night	30% 16% 29% 19% 5%	950
December	1st to 10th	Night	27% 17% 33% 19% 4	950
	11th to 20th	Night	27% 21% 33% 15% 4 1	950
	21st to end	Night	26% 16% 32% 18% 7% 1	1045

Page generated at 2026-05-29 02:53:26. Version ac07

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