Muskoka District Municipality
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Muskoka District Municipality clear sky chart from 2005-11-06 to 2026-07-01.

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	17% 12% 4 8% 5% 4 4 3 5% 6% 31%	138746
	Night	16% 13% 5% 10% 5% 4 4 3 4 5% 29%	133537
Transparency	Day	53% 5% 10% 21% 10% 1	142325
	Night	56% 5% 9% 19% 10% 1	138048
Seeing	Day	25% 16% 30% 19% 8% 2	17025
	Night	24% 13% 29% 24% 9% 1	25874

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% 17% 9% 11% 4 5% 4 3 4 4 25%	4303
	11th to 20th	Day	10% 24% 10% 18% 8% 6% 5% 3 3 2 10%	4868
	21st to end	Day	10% 17% 8% 18% 7% 6% 5% 3 4 4 17%	5780
February	1st to 10th	Day	12% 20% 7% 16% 7% 5% 4 2 4 3 20%	1890
	11th to 20th	Day	14% 16% 6% 15% 5% 5% 3 3 4 6% 23%	1843
	21st to end	Day	17% 19% 6% 12% 6% 5% 3 3 4 5% 20%	1575
March	1st to 10th	Day	18% 15% 5% 11% 5% 5% 4 3 3 5% 26%	5042
	11th to 20th	Day	13% 15% 6% 9% 5% 5% 5% 4 5% 7% 25%	5090
	21st to end	Day	18% 17% 5% 7% 3 3 3 3 4 4 32%	5586
April	1st to 10th	Day	21% 14% 4 8% 4 4 4 3 4 6% 28%	2494
	11th to 20th	Day	24% 11% 3 6% 4 4 3 3 3 4 35%	2607
	21st to end	Day	23% 12% 4 6% 4 4 3 3 4 5% 33%	2730
May	1st to 10th	Day	18% 9% 2 6% 5% 4 5% 4 6% 7% 34%	7793
	11th to 20th	Day	18% 9% 3 7% 4 4 4 3 5% 7% 36%	8221
	21st to end	Day	21% 7% 2 6% 4 4 4 3 5% 6% 38%	9060
June	1st to 10th	Day	20% 8% 3 6% 4 4 4 4 6% 7% 35%	2940
	11th to 20th	Day	15% 6% 3 6% 5% 5% 5% 4 7% 7% 37%	3150
	21st to end	Day	20% 7% 3 6% 4 4 4 3 6% 8% 34%	3150
July	1st to 10th	Day	16% 6% 3 6% 5% 4 5% 4 6% 9% 36%	6820
	11th to 20th	Day	14% 6% 2 6% 4 4 4 3 5% 7% 46%	6465
	21st to end	Day	9% 5% 2 5% 4 4 4 4 6% 8% 49%	6683
August	1st to 10th	Day	14% 7% 3 7% 4 5% 5% 4 5% 9% 35%	4234
	11th to 20th	Day	17% 7% 2 6% 4 5% 5% 4 6% 8% 36%	4174
	21st to end	Day	10% 5% 2 6% 4 5% 5% 5% 6% 9% 44%	4524
September	1st to 10th	Day	16% 7% 2 6% 4 5% 5% 4 5% 8% 39%	2400
	11th to 20th	Day	16% 6% 2 6% 3 4 3 3 5% 7% 44%	2296
	21st to end	Day	20% 10% 2 6% 5% 4 5% 4 4 5% 35%	2150
October	1st to 10th	Day	21% 8% 2 7% 5% 5% 4 4 4 6% 35%	2000
	11th to 20th	Day	26% 12% 3 7% 5% 5% 4 3 5% 6% 24%	2000
	21st to end	Day	31% 13% 3 7% 4 3 5% 3 4 5% 22%	2200
November	1st to 10th	Day	20% 14% 4 8% 5% 4 4 3 5% 6% 27%	1687
	11th to 20th	Day	18% 18% 5% 10% 6% 4 4 4 5% 4 22%	1680
	21st to end	Day	21% 22% 5% 9% 5% 5% 4 3 4 5% 16%	1680
December	1st to 10th	Day	17% 26% 7% 10% 5% 4 4 3 5% 4 14%	2680
	11th to 20th	Day	20% 24% 6% 13% 4 3 3 2 3 3 19%	3066
	21st to end	Day	24% 20% 6% 14% 4 3 3 2 3 4 17%	3885
January	1st to 10th	Night	13% 19% 11% 15% 6% 5% 4 3 4 5% 17%	8557
	11th to 20th	Night	10% 21% 9% 21% 7% 5% 4 3 3 3 12%	8014
	21st to end	Night	10% 17% 9% 16% 8% 7% 4 3 4 4 18%	8401
February	1st to 10th	Night	13% 18% 6% 14% 7% 5% 5% 3 4 5% 21%	2730
	11th to 20th	Night	13% 17% 8% 13% 5% 5% 4 3 4 5% 24%	2663
	21st to end	Night	15% 19% 6% 11% 6% 6% 4 3 4 4 22%	2228
March	1st to 10th	Night	17% 14% 4 11% 4 4 4 3 5% 5% 30%	5018
	11th to 20th	Night	11% 14% 7% 9% 5% 4 5% 4 6% 7% 27%	5089
	21st to end	Night	21% 12% 5% 7% 5% 4 4 3 4 5% 32%	5588
April	1st to 10th	Night	21% 13% 4 7% 4 4 4 4 5% 6% 29%	2125
	11th to 20th	Night	19% 11% 3 7% 4 4 5% 3 4 5% 36%	1981
	21st to end	Night	20% 9% 3 8% 6% 5% 3 4 5% 6% 31%	1890
May	1st to 10th	Night	19% 7% 3 6% 5% 4 4 4 6% 7% 36%	5104
	11th to 20th	Night	18% 7% 2 5% 3 4 3 3 5% 7% 42%	4639
	21st to end	Night	18% 7% 2 5% 3 4 4 3 5% 7% 41%	5114
June	1st to 10th	Night	16% 8% 2 7% 4 5% 3 4 5% 8% 37%	1675
	11th to 20th	Night	14% 7% 2 6% 3 3 5% 4 7% 8% 43%	1470
	21st to end	Night	16% 7% 3 6% 5% 4 5% 4 6% 6% 38%	1470
July	1st to 10th	Night	15% 6% 2 7% 4 4 4 4 5% 8% 41%	3160
	11th to 20th	Night	16% 5% 2 5% 4 3 3 3 5% 6% 48%	3484
	21st to end	Night	12% 5% 2 5% 3 3 4 3 5% 7% 52%	4152
August	1st to 10th	Night	11% 6% 2 6% 4 4 4 4 6% 8% 46%	2915
	11th to 20th	Night	17% 7% 2 5% 3 4 4 3 4 6% 45%	2875
	21st to end	Night	16% 5% 2 5% 3 3 3 3 5% 7% 50%	3340
September	1st to 10th	Night	12% 6% 2 6% 4 3 4 4 6% 7% 45%	2000
	11th to 20th	Night	13% 5% 1 6% 3 2 3 3 5% 8% 50%	2100
	21st to end	Night	19% 7% 2 7% 4 4 3 3 4 5% 42%	2248
October	1st to 10th	Night	20% 8% 2 6% 4 4 4 3 5% 6% 38%	2400
	11th to 20th	Night	25% 11% 3 8% 4 4 4 4 4 6% 28%	2400
	21st to end	Night	27% 14% 4 7% 4 4 3 3 4 4 25%	2640
November	1st to 10th	Night	22% 15% 4 6% 4 3 4 3 5% 5% 30%	2828
	11th to 20th	Night	19% 17% 4 7% 4 5% 4 3 5% 5% 26%	2940
	21st to end	Night	23% 20% 6% 8% 5% 4 4 3 4 5% 17%	2940
December	1st to 10th	Night	20% 24% 7% 11% 4 4 3 3 4 5% 14%	4720
	11th to 20th	Night	17% 24% 7% 16% 5% 4 3 2 3 4 13%	5348
	21st to end	Night	23% 21% 7% 14% 4 4 3 2 3 4 15%	7291

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	63% 3 8% 19% 7%	4304
	11th to 20th	Day	82% 2 4 7% 5%	4899
	21st to end	Day	72% 3 7% 9% 8% 1	5780
February	1st to 10th	Day	71% 3 6% 14% 6% 1	1890
	11th to 20th	Day	65% 4 8% 13% 8% 1	1852
	21st to end	Day	68% 4 6% 14% 7%	1575
March	1st to 10th	Day	61% 5% 11% 9% 14% 1	5045
	11th to 20th	Day	59% 4 12% 15% 8% 2	5090
	21st to end	Day	57% 3 7% 20% 13% 1	5586
April	1st to 10th	Day	59% 4 8% 17% 11% 1	2494
	11th to 20th	Day	54% 4 6% 22% 13% 1	2607
	21st to end	Day	55% 4 7% 19% 12% 3	2730
May	1st to 10th	Day	49% 5% 10% 21% 11% 5%	7802
	11th to 20th	Day	48% 6% 9% 23% 14% 1	8225
	21st to end	Day	47% 4 10% 22% 14% 2	9061
June	1st to 10th	Day	50% 5% 8% 22% 14%	2940
	11th to 20th	Day	44% 7% 10% 23% 14% 1	3150
	21st to end	Day	48% 6% 13% 22% 10% 1	3150
July	1st to 10th	Day	43% 6% 14% 26% 10% 1	6747
	11th to 20th	Day	38% 4 12% 33% 13%	6387
	21st to end	Day	33% 5% 13% 35% 14%	6491
August	1st to 10th	Day	44% 7% 14% 25% 9% 1	4221
	11th to 20th	Day	45% 6% 15% 26% 8%	4213
	21st to end	Day	36% 7% 12% 35% 10%	4524
September	1st to 10th	Day	43% 6% 13% 27% 11% 1	2400
	11th to 20th	Day	39% 5% 12% 30% 13% 1	2296
	21st to end	Day	51% 6% 10% 24% 9%	2150
October	1st to 10th	Day	47% 6% 12% 24% 11% 1	3260
	11th to 20th	Day	53% 6% 11% 22% 8%	3240
	21st to end	Day	60% 5% 13% 17% 6%	3538
November	1st to 10th	Day	58% 5% 12% 19% 6%	1687
	11th to 20th	Day	64% 5% 10% 13% 6% 1	1680
	21st to end	Day	71% 5% 9% 10% 4	1680
December	1st to 10th	Day	74% 4 9% 10% 3	2680
	11th to 20th	Day	73% 3 6% 12% 6%	3066
	21st to end	Day	75% 3 4 12% 7%	3885
January	1st to 10th	Night	71% 3 7% 13% 6%	8557
	11th to 20th	Night	77% 4 5% 6% 7% 1	8058
	21st to end	Night	70% 4 6% 9% 9% 1	8401
February	1st to 10th	Night	66% 5% 8% 14% 6% 1	2730
	11th to 20th	Night	64% 4 8% 17% 7%	2665
	21st to end	Night	66% 4 8% 15% 6% 1	2228
March	1st to 10th	Night	56% 4 10% 13% 12% 4	5028
	11th to 20th	Night	56% 6% 14% 16% 8% 1	5090
	21st to end	Night	56% 4 6% 19% 14% 2	5588
April	1st to 10th	Night	56% 5% 8% 18% 11% 2	2125
	11th to 20th	Night	50% 4 7% 23% 14% 1	1981
	21st to end	Night	54% 4 8% 17% 15% 2	1890
May	1st to 10th	Night	47% 5% 9% 24% 13% 3	5111
	11th to 20th	Night	42% 6% 9% 24% 17% 1	4640
	21st to end	Night	42% 5% 9% 27% 16% 2	5115
June	1st to 10th	Night	45% 6% 10% 21% 16% 2	1675
	11th to 20th	Night	39% 5% 12% 25% 18%	1470
	21st to end	Night	44% 6% 13% 24% 11% 1	1470
July	1st to 10th	Night	42% 5% 13% 27% 12% 1	3125
	11th to 20th	Night	38% 4 10% 34% 13%	3439
	21st to end	Night	33% 5% 9% 38% 15%	4030
August	1st to 10th	Night	37% 5% 16% 26% 16% 1	2904
	11th to 20th	Night	41% 6% 17% 25% 11% 1	2902
	21st to end	Night	35% 5% 11% 35% 13% 1	3340
September	1st to 10th	Night	37% 7% 16% 26% 13% 1	2000
	11th to 20th	Night	34% 6% 13% 32% 15%	2100
	21st to end	Night	45% 5% 11% 27% 12%	2248
October	1st to 10th	Night	39% 5% 10% 28% 18%	3920
	11th to 20th	Night	51% 4 14% 22% 9%	3899
	21st to end	Night	58% 4 14% 16% 7%	4252
November	1st to 10th	Night	56% 5% 11% 21% 7%	2828
	11th to 20th	Night	60% 5% 11% 16% 7% 1	2940
	21st to end	Night	70% 5% 9% 12% 3	2940
December	1st to 10th	Night	74% 4 10% 9% 3	4720
	11th to 20th	Night	77% 4 5% 9% 5%	5348
	21st to end	Night	75% 3 6% 10% 6%	7291

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	25% 21% 36% 11% 5% 1	220
	11th to 20th	Day	27% 20% 38% 10% 4 1	261
	21st to end	Day	27% 18% 36% 16% 3	363
February	1st to 10th	Day	28% 29% 31% 7% 3 1	330
	11th to 20th	Day	31% 23% 38% 7% 2	330
	21st to end	Day	36% 25% 31% 8%	278
March	1st to 10th	Day	27% 20% 37% 13% 3	540
	11th to 20th	Day	26% 22% 33% 14% 4 1	540
	21st to end	Day	33% 18% 30% 14% 5% 1	594
April	1st to 10th	Day	30% 21% 28% 15% 5% 1	540
	11th to 20th	Day	39% 16% 21% 15% 7% 2	532
	21st to end	Day	34% 14% 31% 14% 6% 1	540
May	1st to 10th	Day	28% 14% 31% 19% 6% 2	543
	11th to 20th	Day	23% 16% 29% 21% 8% 3	567
	21st to end	Day	23% 16% 30% 19% 10% 2	617
June	1st to 10th	Day	24% 14% 32% 24% 5% 2	570
	11th to 20th	Day	18% 16% 30% 25% 9% 2	780
	21st to end	Day	21% 13% 36% 21% 7% 2	780
July	1st to 10th	Day	13% 10% 33% 31% 11% 2	722
	11th to 20th	Day	16% 11% 27% 29% 13% 3	574
	21st to end	Day	13% 13% 32% 27% 11% 5%	576
August	1st to 10th	Day	14% 8% 27% 30% 15% 6%	526
	11th to 20th	Day	17% 6% 25% 30% 15% 8%	519
	21st to end	Day	16% 9% 31% 25% 13% 6%	583
September	1st to 10th	Day	18% 10% 29% 22% 14% 7%	530
	11th to 20th	Day	16% 7% 24% 25% 20% 9%	530
	21st to end	Day	22% 14% 23% 26% 11% 3	530
October	1st to 10th	Day	26% 13% 25% 19% 13% 3	530
	11th to 20th	Day	28% 18% 34% 15% 5% 1	530
	21st to end	Day	37% 17% 29% 14% 3	583
November	1st to 10th	Day	40% 16% 28% 15% 2	245
	11th to 20th	Day	29% 25% 31% 11% 4	220
	21st to end	Day	34% 24% 32% 8% 2	220
December	1st to 10th	Day	31% 21% 31% 13% 3 1	220
	11th to 20th	Day	40% 24% 21% 12% 2	220
	21st to end	Day	38% 22% 26% 10% 3 1	242
January	1st to 10th	Night	29% 17% 32% 18% 4	958
	11th to 20th	Night	29% 18% 30% 18% 4 1	840
	21st to end	Night	21% 13% 36% 21% 7% 1	924
February	1st to 10th	Night	23% 20% 33% 21% 3	840
	11th to 20th	Night	23% 18% 34% 19% 6%	823
	21st to end	Night	27% 19% 28% 21% 4	692
March	1st to 10th	Night	23% 18% 36% 21% 3	840
	11th to 20th	Night	24% 16% 35% 20% 4 1	840
	21st to end	Night	23% 15% 30% 24% 7% 1	924
April	1st to 10th	Night	28% 15% 32% 20% 5%	840
	11th to 20th	Night	26% 14% 30% 20% 9% 1	737
	21st to end	Night	24% 13% 30% 25% 8%	630
May	1st to 10th	Night	22% 6% 28% 31% 11% 2	579
	11th to 20th	Night	18% 11% 31% 29% 10%	414
	21st to end	Night	15% 9% 32% 33% 11%	455
June	1st to 10th	Night	20% 7% 30% 32% 10%	420
	11th to 20th	Night	16% 10% 25% 35% 13%	420
	21st to end	Night	19% 6% 25% 38% 12%	420
July	1st to 10th	Night	13% 4 22% 43% 17% 1	390
	11th to 20th	Night	16% 4 25% 36% 19% 1	388
	21st to end	Night	11% 4 25% 38% 21% 1	537
August	1st to 10th	Night	13% 4 16% 41% 25% 2	597
	11th to 20th	Night	14% 4 18% 38% 23% 3	594
	21st to end	Night	18% 6% 24% 30% 20% 2	725
September	1st to 10th	Night	16% 7% 26% 32% 17% 3	800
	11th to 20th	Night	14% 6% 25% 30% 22% 4	800
	21st to end	Night	21% 8% 22% 30% 17% 2	800
October	1st to 10th	Night	23% 10% 27% 25% 13% 1	800
	11th to 20th	Night	29% 12% 30% 20% 8% 1	800
	21st to end	Night	34% 15% 28% 20% 4	880
November	1st to 10th	Night	33% 12% 24% 24% 6%	820
	11th to 20th	Night	29% 17% 28% 20% 6%	840
	21st to end	Night	35% 14% 28% 19% 4	840
December	1st to 10th	Night	34% 19% 28% 15% 4	840
	11th to 20th	Night	30% 17% 34% 14% 3 1	840
	21st to end	Night	35% 14% 29% 19% 3	987

Page generated at 2026-06-28 02:10:49. Version ac07

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