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 2024-09-14.

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 7% 5% 4 4 4 5% 7% 36%	101261
	Night	18% 10% 4 8% 5% 5% 4 4 5% 6% 31%	96744
Transparency	Day	47% 7% 15% 21% 10% 1	101005
	Night	52% 7% 13% 19% 9% 1	96620
Seeing	Day	21% 8% 28% 28% 13% 2	16529
	Night	23% 10% 28% 27% 10% 1	23947

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% 11% 5% 12% 7% 5% 6% 5% 6% 4 26%	2207
	11th to 20th	Day	12% 13% 3 9% 7% 5% 6% 5% 8% 7% 25%	2210
	21st to end	Day	7% 7% 4 9% 7% 6% 6% 5% 7% 8% 34%	2947
February	1st to 10th	Day	11% 13% 4 9% 6% 5% 4 4 6% 5% 32%	1710
	11th to 20th	Day	13% 14% 4 8% 6% 5% 4 3 5% 5% 32%	1663
	21st to end	Day	10% 11% 4 6% 6% 5% 4 4 5% 6% 38%	1413
March	1st to 10th	Day	15% 13% 4 9% 4 4 5% 3 5% 6% 33%	3351
	11th to 20th	Day	16% 14% 4 11% 6% 5% 5% 3 4 5% 26%	3480
	21st to end	Day	24% 11% 3 7% 4 4 4 3 3 5% 32%	3816
April	1st to 10th	Day	20% 11% 3 6% 4 3 3 4 5% 5% 36%	2270
	11th to 20th	Day	19% 9% 2 6% 5% 4 4 4 5% 6% 37%	2418
	21st to end	Day	23% 8% 3 7% 4 4 3 3 5% 6% 33%	2470
May	1st to 10th	Day	19% 10% 4 7% 5% 4 4 4 5% 7% 30%	4346
	11th to 20th	Day	17% 8% 2 7% 4 4 4 3 5% 7% 38%	4398
	21st to end	Day	19% 9% 3 7% 5% 4 4 3 6% 8% 32%	4987
June	1st to 10th	Day	25% 8% 2 7% 4 4 4 3 5% 6% 31%	2850
	11th to 20th	Day	17% 8% 2 6% 5% 4 4 3 5% 8% 39%	2850
	21st to end	Day	24% 8% 3 6% 4 4 4 4 6% 6% 31%	2850
July	1st to 10th	Day	13% 6% 3 7% 4 5% 5% 4 6% 8% 39%	4760
	11th to 20th	Day	11% 7% 3 7% 5% 5% 5% 4 7% 7% 40%	4760
	21st to end	Day	12% 5% 2 5% 3 3 4 4 6% 8% 49%	4915
August	1st to 10th	Day	14% 6% 2 6% 4 5% 5% 4 6% 8% 40%	4151
	11th to 20th	Day	13% 5% 2 6% 5% 5% 4 4 6% 8% 43%	4045
	21st to end	Day	14% 5% 2 5% 3 3 4 3 6% 8% 49%	4470
September	1st to 10th	Day	16% 6% 2 6% 4 4 4 3 6% 5% 43%	2280
	11th to 20th	Day	17% 7% 3 6% 3 3 3 3 4 5% 46%	2119
	21st to end	Day	19% 6% 2 5% 4 3 3 2 5% 7% 44%	1935
October	1st to 10th	Day	15% 7% 3 6% 5% 4 4 3 5% 6% 42%	1800
	11th to 20th	Day	18% 9% 3 7% 4 4 4 4 5% 7% 35%	1800
	21st to end	Day	22% 10% 2 7% 4 3 4 3 5% 6% 33%	1874
November	1st to 10th	Day	20% 9% 3 6% 5% 5% 4 3 5% 6% 34%	1485
	11th to 20th	Day	20% 12% 5% 8% 5% 5% 5% 4 6% 5% 27%	1520
	21st to end	Day	18% 16% 5% 10% 6% 4 4 4 5% 5% 23%	1520
December	1st to 10th	Day	22% 13% 4 10% 7% 5% 4 3 4 5% 22%	1492
	11th to 20th	Day	18% 12% 5% 13% 8% 5% 6% 3 4 5% 21%	1668
	21st to end	Day	17% 11% 5% 10% 6% 5% 4 3 5% 6% 28%	2431
January	1st to 10th	Night	11% 12% 5% 13% 8% 6% 6% 4 6% 6% 23%	4748
	11th to 20th	Night	18% 11% 4 11% 8% 6% 5% 4 6% 6% 22%	4760
	21st to end	Night	9% 12% 4 8% 8% 4 4 4 6% 7% 35%	4709
February	1st to 10th	Night	12% 14% 4 8% 6% 5% 4 4 5% 5% 32%	2470
	11th to 20th	Night	15% 13% 4 8% 5% 6% 4 3 4 5% 32%	2403
	21st to end	Night	14% 11% 4 7% 6% 5% 4 4 5% 5% 34%	2041
March	1st to 10th	Night	13% 12% 4 10% 6% 7% 5% 4 5% 5% 31%	3484
	11th to 20th	Night	24% 16% 5% 10% 5% 5% 4 3 4 5% 20%	3479
	21st to end	Night	27% 12% 3 6% 5% 3 3 3 4 7% 29%	3816
April	1st to 10th	Night	23% 11% 4 7% 5% 4 4 3 4 5% 30%	1909
	11th to 20th	Night	20% 9% 3 6% 3 3 4 4 6% 6% 35%	1709
	21st to end	Night	23% 10% 3 7% 4 4 3 3 4 5% 34%	1710
May	1st to 10th	Night	23% 11% 4 8% 5% 4 4 3 4 5% 28%	2601
	11th to 20th	Night	14% 7% 3 6% 4 4 5% 4 6% 7% 39%	2506
	21st to end	Night	16% 10% 4 8% 6% 6% 5% 4 7% 7% 27%	2626
June	1st to 10th	Night	26% 9% 3 7% 4 4 3 4 4 7% 29%	1330
	11th to 20th	Night	19% 8% 2 5% 3 5% 3 4 7% 7% 37%	1330
	21st to end	Night	24% 8% 3 6% 5% 4 5% 5% 6% 5% 29%	1330
July	1st to 10th	Night	14% 7% 3 6% 5% 5% 4 4 6% 8% 39%	2210
	11th to 20th	Night	14% 7% 2 7% 5% 5% 6% 4 7% 7% 36%	2210
	21st to end	Night	11% 6% 2 5% 4 4 4 4 7% 7% 46%	2615
August	1st to 10th	Night	15% 9% 3 9% 6% 5% 6% 5% 5% 7% 31%	2777
	11th to 20th	Night	11% 8% 2 6% 5% 4 5% 4 6% 7% 40%	2782
	21st to end	Night	13% 4 2 5% 3 4 4 3 6% 8% 48%	3185
September	1st to 10th	Night	18% 7% 2 6% 4 5% 4 3 5% 7% 42%	1900
	11th to 20th	Night	18% 6% 2 5% 4 3 4 2 5% 6% 46%	1918
	21st to end	Night	17% 5% 2 5% 3 2 4 3 5% 6% 46%	2024
October	1st to 10th	Night	18% 7% 2 6% 4 4 4 4 5% 6% 41%	2160
	11th to 20th	Night	20% 8% 3 7% 4 4 4 3 5% 6% 36%	2160
	21st to end	Night	23% 10% 2 8% 4 4 4 3 4 5% 33%	2479
November	1st to 10th	Night	21% 9% 4 7% 4 4 4 3 5% 6% 33%	2593
	11th to 20th	Night	21% 13% 4 8% 6% 4 4 4 5% 6% 25%	2660
	21st to end	Night	22% 14% 5% 9% 5% 5% 3 3 5% 6% 23%	2660
December	1st to 10th	Night	23% 14% 5% 9% 6% 4 3 4 6% 5% 21%	2683
	11th to 20th	Night	23% 13% 6% 11% 8% 5% 4 3 5% 6% 17%	3531
	21st to end	Night	18% 13% 4 11% 6% 5% 4 3 5% 6% 25%	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% 10% 9% 16% 9%	2208
	11th to 20th	Day	50% 19% 9% 11% 11%	2210
	21st to end	Day	40% 12% 16% 23% 9% 1	2947
February	1st to 10th	Day	50% 6% 13% 19% 10% 2	1710
	11th to 20th	Day	53% 6% 10% 20% 10% 1	1671
	21st to end	Day	45% 6% 10% 24% 13% 3	1413
March	1st to 10th	Day	49% 8% 14% 21% 7% 1	3355
	11th to 20th	Day	60% 6% 9% 16% 7% 2	3480
	21st to end	Day	55% 5% 7% 20% 11% 2	3816
April	1st to 10th	Day	49% 5% 10% 19% 16% 2	2270
	11th to 20th	Day	46% 6% 12% 23% 13% 1	2418
	21st to end	Day	51% 5% 10% 16% 14% 3	2470
May	1st to 10th	Day	51% 8% 12% 21% 8%	4361
	11th to 20th	Day	45% 5% 16% 26% 8% 1	4402
	21st to end	Day	48% 9% 13% 20% 10% 1	4987
June	1st to 10th	Day	53% 6% 12% 19% 9%	2850
	11th to 20th	Day	43% 6% 14% 24% 11% 1	2850
	21st to end	Day	53% 6% 13% 19% 8%	2850
July	1st to 10th	Day	41% 7% 20% 22% 10%	4685
	11th to 20th	Day	41% 7% 18% 26% 8%	4679
	21st to end	Day	33% 8% 25% 24% 10%	4758
August	1st to 10th	Day	41% 7% 19% 23% 9%	4137
	11th to 20th	Day	39% 7% 20% 23% 10% 1	4084
	21st to end	Day	34% 5% 19% 28% 13% 1	4470
September	1st to 10th	Day	41% 7% 15% 26% 12%	2280
	11th to 20th	Day	41% 6% 14% 26% 13%	2119
	21st to end	Day	41% 6% 13% 27% 13% 1	1935
October	1st to 10th	Day	42% 5% 15% 26% 9% 2	1800
	11th to 20th	Day	48% 6% 18% 21% 7% 1	1800
	21st to end	Day	51% 6% 14% 20% 8%	1874
November	1st to 10th	Day	52% 7% 13% 19% 8% 1	1485
	11th to 20th	Day	56% 8% 14% 14% 7%	1520
	21st to end	Day	62% 8% 13% 11% 5%	1520
December	1st to 10th	Day	64% 9% 12% 10% 5%	1492
	11th to 20th	Day	65% 7% 11% 11% 6%	1668
	21st to end	Day	56% 7% 14% 15% 6% 1	2431
January	1st to 10th	Night	55% 10% 17% 14% 3	4748
	11th to 20th	Night	58% 10% 11% 14% 6% 1	4760
	21st to end	Night	45% 8% 16% 20% 11% 1	4709
February	1st to 10th	Night	52% 5% 11% 17% 13% 2	2470
	11th to 20th	Night	55% 5% 11% 18% 11% 1	2406
	21st to end	Night	49% 5% 9% 21% 13% 2	2041
March	1st to 10th	Night	53% 7% 10% 20% 9% 1	3493
	11th to 20th	Night	66% 5% 7% 13% 6% 1	3480
	21st to end	Night	57% 5% 7% 17% 12% 2	3816
April	1st to 10th	Night	56% 5% 9% 14% 14% 2	1909
	11th to 20th	Night	48% 4 10% 21% 15% 2	1709
	21st to end	Night	53% 5% 8% 16% 16% 2	1710
May	1st to 10th	Night	58% 6% 8% 18% 9% 1	2606
	11th to 20th	Night	42% 8% 15% 27% 7% 1	2507
	21st to end	Night	53% 9% 12% 18% 8% 1	2627
June	1st to 10th	Night	56% 5% 11% 21% 8%	1330
	11th to 20th	Night	46% 6% 13% 22% 12% 2	1330
	21st to end	Night	56% 8% 13% 15% 8% 1	1330
July	1st to 10th	Night	43% 6% 18% 19% 13%	2175
	11th to 20th	Night	46% 7% 13% 28% 5%	2168
	21st to end	Night	36% 8% 23% 23% 9%	2532
August	1st to 10th	Night	51% 9% 14% 19% 7%	2766
	11th to 20th	Night	42% 7% 17% 25% 8%	2809
	21st to end	Night	34% 5% 19% 28% 14%	3184
September	1st to 10th	Night	42% 6% 14% 28% 9% 1	1900
	11th to 20th	Night	39% 6% 13% 28% 13%	1918
	21st to end	Night	38% 7% 13% 27% 14% 1	2024
October	1st to 10th	Night	43% 5% 12% 25% 13% 1	2160
	11th to 20th	Night	48% 6% 15% 24% 7%	2160
	21st to end	Night	55% 6% 12% 19% 8%	2479
November	1st to 10th	Night	52% 5% 14% 19% 8% 1	2593
	11th to 20th	Night	57% 7% 13% 15% 7%	2660
	21st to end	Night	63% 7% 15% 10% 5%	2660
December	1st to 10th	Night	64% 8% 11% 13% 4	2683
	11th to 20th	Night	69% 6% 8% 13% 5%	3532
	21st to end	Night	58% 9% 14% 14% 5%	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	26% 13% 36% 18% 8%	180
	11th to 20th	Day	29% 18% 27% 16% 9% 1	180
	21st to end	Day	14% 12% 34% 27% 12% 2	354
February	1st to 10th	Day	21% 12% 32% 25% 8% 2	370
	11th to 20th	Day	17% 13% 39% 22% 7% 1	366
	21st to end	Day	18% 10% 35% 27% 9% 1	307
March	1st to 10th	Day	19% 11% 35% 28% 6% 2	449
	11th to 20th	Day	16% 12% 30% 27% 13% 2	460
	21st to end	Day	23% 11% 31% 25% 7% 3	506
April	1st to 10th	Day	27% 14% 28% 23% 7%	460
	11th to 20th	Day	21% 9% 33% 25% 10% 2	452
	21st to end	Day	26% 8% 27% 25% 11% 2	460
May	1st to 10th	Day	26% 6% 26% 28% 12% 3	600
	11th to 20th	Day	22% 5% 25% 25% 20% 4	674
	21st to end	Day	22% 6% 30% 30% 11% 2	735
June	1st to 10th	Day	28% 4 24% 29% 12% 3	680
	11th to 20th	Day	19% 4 23% 34% 16% 3	680
	21st to end	Day	26% 4 23% 30% 14% 2	680
July	1st to 10th	Day	18% 4 26% 33% 14% 4	670
	11th to 20th	Day	14% 4 22% 39% 19% 3	668
	21st to end	Day	18% 4 18% 35% 21% 4	740
August	1st to 10th	Day	12% 6% 21% 34% 23% 3	519
	11th to 20th	Day	16% 4 20% 35% 21% 4	479
	21st to end	Day	14% 5% 20% 35% 20% 5%	539
September	1st to 10th	Day	17% 5% 29% 33% 14% 2	490
	11th to 20th	Day	21% 7% 26% 31% 13% 3	463
	21st to end	Day	21% 8% 32% 25% 11% 3	427
October	1st to 10th	Day	16% 8% 31% 28% 15% 2	360
	11th to 20th	Day	23% 10% 33% 19% 13% 3	360
	21st to end	Day	27% 13% 31% 21% 8% 1	396
November	1st to 10th	Day	21% 15% 34% 22% 7% 1	365
	11th to 20th	Day	27% 14% 30% 20% 6% 2	370
	21st to end	Day	26% 16% 35% 18% 4	370
December	1st to 10th	Day	26% 14% 33% 20% 7% 1	342
	11th to 20th	Day	22% 25% 30% 19% 4	180
	21st to end	Day	21% 21% 35% 17% 6%	198
January	1st to 10th	Night	24% 12% 36% 21% 6% 1	850
	11th to 20th	Night	22% 13% 34% 25% 6%	850
	21st to end	Night	19% 10% 36% 23% 10% 1	859
February	1st to 10th	Night	19% 12% 35% 25% 8% 2	760
	11th to 20th	Night	23% 12% 34% 24% 6% 2	743
	21st to end	Night	20% 9% 32% 27% 11% 1	628
March	1st to 10th	Night	19% 10% 34% 29% 6% 1	760
	11th to 20th	Night	20% 9% 33% 27% 10% 1	760
	21st to end	Night	23% 10% 29% 29% 8% 1	836
April	1st to 10th	Night	26% 10% 27% 28% 8% 1	579
	11th to 20th	Night	23% 6% 31% 27% 12% 1	564
	21st to end	Night	25% 10% 25% 27% 11% 2	570
May	1st to 10th	Night	28% 5% 21% 30% 13% 3	570
	11th to 20th	Night	22% 4 23% 31% 17% 3	562
	21st to end	Night	19% 6% 30% 33% 11% 2	545
June	1st to 10th	Night	29% 4 18% 32% 15% 1	380
	11th to 20th	Night	22% 3 22% 30% 20% 3	380
	21st to end	Night	26% 3 16% 38% 15% 2	380
July	1st to 10th	Night	18% 4 18% 38% 19% 3	370
	11th to 20th	Night	15% 5% 17% 43% 18% 2	368
	21st to end	Night	18% 4 19% 38% 19% 2	540
August	1st to 10th	Night	18% 3 17% 40% 20% 2	568
	11th to 20th	Night	18% 3 15% 41% 21% 2	562
	21st to end	Night	14% 4 20% 36% 23% 4	627
September	1st to 10th	Night	21% 6% 25% 34% 12% 2	570
	11th to 20th	Night	19% 8% 21% 35% 16% 1	631
	21st to end	Night	20% 7% 30% 30% 12%	720
October	1st to 10th	Night	20% 7% 32% 28% 11% 1	720
	11th to 20th	Night	23% 10% 29% 26% 11% 1	720
	21st to end	Night	27% 14% 29% 23% 7% 1	810
November	1st to 10th	Night	26% 15% 30% 21% 7% 1	830
	11th to 20th	Night	26% 16% 29% 20% 6% 2	850
	21st to end	Night	28% 16% 29% 20% 5%	850
December	1st to 10th	Night	29% 16% 32% 19% 4	850
	11th to 20th	Night	27% 19% 33% 16% 5% 1	850
	21st to end	Night	27% 16% 32% 18% 6% 1	935

Page generated at 2024-09-11 11:00:06. Version ac07

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