Kluane Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kluane Lake clear sky chart from 2005-11-06 to 2026-04-02.

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	6% 7% 3 8% 6% 7% 7% 6% 8% 10% 32%	134417
	Night	3 7% 3 10% 7% 7% 7% 6% 9% 11% 29%	136048
Transparency	Day	42% 13% 17% 18% 8% 1	134060
	Night	40% 13% 16% 19% 10% 2	135985
Seeing	Day	10% 11% 25% 28% 19% 7%	18725
	Night	7% 9% 25% 32% 22% 6%	24824

By Month

Percentage Cloud Cover NW (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	2 1 8% 7% 9% 9% 8% 12% 11% 32%	2901
	11th to 20th	Day	4 2 9% 8% 8% 8% 6% 10% 10% 36%	2925
	21st to end	Day	2 1 5% 7% 10% 10% 7% 10% 11% 36%	3889
February	1st to 10th	Day	1 4 4 8% 7% 8% 8% 6% 8% 12% 35%	1470
	11th to 20th	Day	1 5% 4 10% 8% 6% 7% 6% 9% 12% 33%	1596
	21st to end	Day	4 4 10% 9% 10% 8% 6% 8% 10% 31%	1557
March	1st to 10th	Day	3 3 9% 9% 10% 7% 6% 7% 10% 36%	4287
	11th to 20th	Day	3 3 7% 8% 7% 8% 6% 10% 12% 36%	5076
	21st to end	Day	3 2 8% 6% 7% 7% 6% 10% 15% 37%	5834
April	1st to 10th	Day	7% 4 11% 6% 5% 6% 6% 10% 12% 32%	2558
	11th to 20th	Day	1 10% 4 8% 6% 6% 6% 6% 9% 9% 35%	2686
	21st to end	Day	1 7% 4 8% 5% 6% 7% 6% 8% 11% 37%	2883
May	1st to 10th	Day	1 5% 2 9% 6% 6% 7% 6% 9% 12% 37%	7056
	11th to 20th	Day	4 9% 3 9% 7% 6% 7% 6% 8% 10% 30%	7234
	21st to end	Day	5% 8% 3 7% 6% 6% 7% 6% 9% 10% 33%	8445
June	1st to 10th	Day	10% 7% 3 7% 6% 6% 6% 5% 8% 10% 31%	3600
	11th to 20th	Day	14% 10% 3 9% 7% 6% 6% 5% 7% 9% 24%	3600
	21st to end	Day	11% 7% 3 8% 7% 6% 8% 6% 8% 10% 27%	3600
July	1st to 10th	Day	11% 7% 3 8% 7% 7% 8% 6% 7% 9% 28%	8006
	11th to 20th	Day	10% 7% 3 7% 6% 7% 7% 5% 9% 11% 29%	7700
	21st to end	Day	17% 7% 3 7% 5% 5% 5% 4 7% 10% 31%	8205
August	1st to 10th	Day	8% 5% 2 5% 4 5% 6% 5% 7% 9% 45%	4961
	11th to 20th	Day	12% 7% 2 6% 5% 6% 5% 5% 7% 9% 35%	4739
	21st to end	Day	12% 11% 3 8% 6% 7% 7% 6% 8% 9% 24%	4878
September	1st to 10th	Day	8% 8% 4 8% 6% 7% 7% 4 7% 10% 31%	2530
	11th to 20th	Day	6% 8% 3 7% 6% 6% 6% 6% 8% 9% 35%	2394
	21st to end	Day	6% 12% 3 8% 6% 6% 6% 6% 7% 10% 29%	2108
October	1st to 10th	Day	4 9% 3 9% 8% 8% 8% 7% 9% 10% 25%	3270
	11th to 20th	Day	2 8% 4 13% 8% 7% 7% 5% 7% 10% 29%	2847
	21st to end	Day	4 12% 5% 16% 8% 8% 8% 5% 8% 8% 19%	2842
November	1st to 10th	Day	1 9% 7% 15% 8% 7% 7% 6% 7% 9% 24%	1399
	11th to 20th	Day	1 8% 6% 15% 14% 9% 9% 8% 11% 7% 15%	1260
	21st to end	Day	1 7% 4 12% 6% 9% 10% 9% 11% 14% 20%	1175
December	1st to 10th	Day	1 5% 4 11% 7% 6% 7% 8% 9% 12% 30%	1340
	11th to 20th	Day	3 2 9% 7% 7% 9% 8% 12% 9% 34%	1542
	21st to end	Day	4 3 11% 7% 7% 8% 7% 9% 14% 30%	2024
January	1st to 10th	Night	3 2 8% 8% 8% 9% 8% 12% 13% 29%	10048
	11th to 20th	Night	5% 3 9% 7% 6% 6% 5% 8% 12% 37%	9973
	21st to end	Night	3 2 8% 7% 8% 9% 7% 10% 11% 35%	10304
February	1st to 10th	Night	1 6% 3 10% 9% 8% 8% 6% 10% 12% 28%	3150
	11th to 20th	Night	5% 3 10% 7% 6% 8% 7% 10% 13% 29%	2909
	21st to end	Night	6% 3 14% 10% 9% 8% 6% 8% 11% 24%	2249
March	1st to 10th	Night	4 4 11% 9% 9% 8% 6% 8% 11% 30%	5807
	11th to 20th	Night	1 7% 4 12% 8% 9% 8% 7% 8% 11% 27%	5100
	21st to end	Night	5% 5% 14% 9% 7% 6% 5% 8% 13% 28%	5349
April	1st to 10th	Night	1 8% 5% 12% 6% 5% 6% 5% 8% 12% 32%	1865
	11th to 20th	Night	1 11% 5% 8% 6% 5% 7% 5% 9% 9% 34%	1663
	21st to end	Night	2 9% 5% 9% 6% 5% 5% 6% 8% 11% 35%	1515
May	1st to 10th	Night	1 6% 2 8% 6% 7% 8% 7% 9% 12% 34%	2912
	11th to 20th	Night	5% 12% 4 9% 6% 6% 6% 5% 6% 7% 33%	2659
	21st to end	Night	7% 9% 3 7% 5% 6% 8% 5% 8% 9% 33%	2429
June	1st to 10th	Night	10% 6% 3 7% 6% 6% 6% 7% 8% 10% 30%	800
	11th to 20th	Night	16% 10% 4 9% 6% 6% 6% 5% 8% 8% 25%	800
	21st to end	Night	12% 7% 3 7% 5% 7% 9% 5% 10% 14% 22%	800
July	1st to 10th	Night	14% 8% 3 9% 7% 6% 6% 4 7% 9% 27%	1938
	11th to 20th	Night	14% 8% 3 8% 6% 6% 8% 6% 7% 10% 24%	2260
	21st to end	Night	21% 10% 2 7% 4 5% 5% 5% 6% 10% 26%	2638
August	1st to 10th	Night	11% 5% 2 6% 5% 4 5% 5% 8% 8% 41%	2183
	11th to 20th	Night	16% 8% 3 6% 4 4 4 4 7% 9% 36%	2319
	21st to end	Night	10% 10% 3 8% 6% 7% 7% 6% 7% 7% 28%	3028
September	1st to 10th	Night	10% 8% 3 8% 6% 6% 6% 5% 8% 8% 31%	1870
	11th to 20th	Night	7% 7% 3 8% 5% 6% 5% 6% 8% 9% 36%	2005
	21st to end	Night	8% 14% 3 8% 5% 6% 6% 5% 8% 7% 29%	2291
October	1st to 10th	Night	4 12% 4 10% 6% 7% 7% 4 7% 10% 29%	3920
	11th to 20th	Night	3 10% 5% 17% 7% 6% 8% 4 6% 8% 25%	4299
	21st to end	Night	3 12% 7% 20% 10% 9% 7% 4 6% 6% 17%	4959
November	1st to 10th	Night	1 10% 5% 12% 10% 8% 8% 6% 9% 11% 20%	3118
	11th to 20th	Night	1 9% 7% 16% 12% 8% 8% 5% 8% 9% 16%	3360
	21st to end	Night	1 7% 3 11% 8% 8% 9% 7% 13% 13% 20%	3434
December	1st to 10th	Night	1 5% 3 11% 8% 7% 7% 7% 9% 11% 31%	6050
	11th to 20th	Night	4 2 8% 8% 8% 9% 7% 10% 12% 32%	6870
	21st to end	Night	1 5% 3 11% 8% 8% 8% 7% 11% 13% 26%	9174

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	33% 8% 15% 19% 21% 3	2901
	11th to 20th	Day	35% 10% 17% 23% 10% 5%	2940
	21st to end	Day	28% 14% 22% 20% 11% 5%	3890
February	1st to 10th	Day	38% 12% 12% 18% 16% 5%	1470
	11th to 20th	Day	39% 14% 15% 15% 12% 5%	1603
	21st to end	Day	44% 12% 11% 17% 12% 4	1557
March	1st to 10th	Day	35% 12% 11% 21% 18% 2	4287
	11th to 20th	Day	33% 13% 15% 16% 22% 2	5076
	21st to end	Day	30% 17% 18% 21% 13% 2	5834
April	1st to 10th	Day	43% 16% 17% 17% 6% 1	2558
	11th to 20th	Day	43% 14% 16% 18% 8% 1	2686
	21st to end	Day	39% 16% 20% 19% 5%	2883
May	1st to 10th	Day	35% 13% 16% 21% 13% 1	7056
	11th to 20th	Day	44% 14% 16% 20% 7% 1	7237
	21st to end	Day	39% 13% 14% 20% 13%	8446
June	1st to 10th	Day	47% 14% 17% 14% 7%	3600
	11th to 20th	Day	56% 13% 15% 12% 4	3600
	21st to end	Day	51% 15% 17% 15% 3	3600
July	1st to 10th	Day	48% 12% 18% 17% 3	7920
	11th to 20th	Day	45% 12% 20% 20% 3	7607
	21st to end	Day	46% 11% 23% 18% 2	7973
August	1st to 10th	Day	34% 12% 23% 20% 10% 1	4942
	11th to 20th	Day	45% 11% 20% 22% 2	4784
	21st to end	Day	53% 12% 17% 17% 1	4877
September	1st to 10th	Day	49% 14% 15% 18% 4	2530
	11th to 20th	Day	42% 16% 17% 21% 4	2394
	21st to end	Day	48% 14% 15% 19% 4	2108
October	1st to 10th	Day	48% 14% 15% 18% 5%	3270
	11th to 20th	Day	45% 14% 17% 19% 5%	2847
	21st to end	Day	52% 16% 17% 11% 4 1	2842
November	1st to 10th	Day	48% 12% 14% 16% 8% 2	1399
	11th to 20th	Day	58% 11% 9% 14% 8% 1	1260
	21st to end	Day	45% 14% 14% 17% 10% 1	1175
December	1st to 10th	Day	41% 13% 25% 16% 5% 1	1340
	11th to 20th	Day	37% 13% 17% 15% 18% 1	1544
	21st to end	Day	33% 20% 15% 18% 12% 2	2024
January	1st to 10th	Night	33% 10% 14% 22% 19% 2	10049
	11th to 20th	Night	33% 10% 19% 22% 12% 5%	10020
	21st to end	Night	30% 14% 18% 23% 12% 4	10304
February	1st to 10th	Night	41% 11% 12% 18% 14% 5%	3150
	11th to 20th	Night	39% 13% 13% 17% 13% 4	2913
	21st to end	Night	45% 10% 12% 18% 11% 4	2249
March	1st to 10th	Night	38% 11% 12% 23% 16% 1	5807
	11th to 20th	Night	40% 14% 12% 18% 14% 2	5102
	21st to end	Night	35% 16% 19% 20% 8% 1	5349
April	1st to 10th	Night	42% 14% 19% 18% 8% 1	1865
	11th to 20th	Night	42% 13% 17% 17% 9% 1	1663
	21st to end	Night	39% 16% 19% 18% 8%	1515
May	1st to 10th	Night	34% 15% 16% 18% 15% 1	2909
	11th to 20th	Night	42% 13% 13% 23% 8%	2659
	21st to end	Night	39% 14% 13% 22% 12%	2429
June	1st to 10th	Night	45% 13% 19% 18% 5% 1	800
	11th to 20th	Night	52% 14% 17% 15% 3	800
	21st to end	Night	49% 17% 20% 14% 1	800
July	1st to 10th	Night	47% 11% 18% 20% 4	1915
	11th to 20th	Night	50% 11% 20% 20%	2230
	21st to end	Night	49% 11% 21% 18% 1	2565
August	1st to 10th	Night	37% 12% 21% 20% 9% 1	2177
	11th to 20th	Night	44% 9% 19% 24% 4	2340
	21st to end	Night	50% 13% 15% 20% 2	3028
September	1st to 10th	Night	47% 15% 19% 16% 3	1870
	11th to 20th	Night	42% 14% 18% 21% 5%	2005
	21st to end	Night	50% 13% 15% 16% 5% 1	2291
October	1st to 10th	Night	44% 13% 13% 25% 4 1	3920
	11th to 20th	Night	52% 15% 9% 17% 6% 1	4299
	21st to end	Night	57% 16% 12% 10% 4 1	4959
November	1st to 10th	Night	50% 15% 13% 16% 7% 1	3118
	11th to 20th	Night	57% 11% 10% 14% 7% 1	3360
	21st to end	Night	43% 16% 15% 18% 8% 1	3434
December	1st to 10th	Night	40% 13% 18% 23% 6% 1	6050
	11th to 20th	Night	38% 12% 19% 17% 14% 1	6867
	21st to end	Night	36% 18% 17% 17% 10% 2	9174

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	2 11% 17% 31% 26% 13%	110
	11th to 20th	Day	3 10% 20% 33% 26% 8%	110
	21st to end	Day	5% 14% 27% 31% 15% 9%	287
February	1st to 10th	Day	3 7% 25% 34% 23% 7%	430
	11th to 20th	Day	2 13% 28% 32% 16% 9%	425
	21st to end	Day	3 10% 31% 36% 13% 8%	355
March	1st to 10th	Day	2 10% 25% 27% 23% 14%	430
	11th to 20th	Day	1 11% 31% 26% 19% 11%	430
	21st to end	Day	2 8% 28% 27% 23% 12%	530
April	1st to 10th	Day	2 12% 31% 32% 20% 4	650
	11th to 20th	Day	6% 12% 22% 31% 24% 5%	690
	21st to end	Day	4 10% 23% 33% 24% 6%	700
May	1st to 10th	Day	8% 15% 31% 28% 16% 3	703
	11th to 20th	Day	9% 11% 24% 30% 19% 8%	725
	21st to end	Day	9% 12% 27% 32% 16% 4	800
June	1st to 10th	Day	12% 9% 27% 29% 19% 4	930
	11th to 20th	Day	16% 8% 24% 26% 20% 6%	930
	21st to end	Day	12% 8% 19% 27% 25% 9%	930
July	1st to 10th	Day	14% 6% 21% 29% 23% 6%	856
	11th to 20th	Day	16% 12% 21% 26% 19% 5%	718
	21st to end	Day	14% 9% 21% 29% 20% 6%	794
August	1st to 10th	Day	12% 9% 25% 25% 23% 6%	726
	11th to 20th	Day	17% 16% 24% 23% 15% 6%	715
	21st to end	Day	15% 13% 27% 27% 16% 2	803
September	1st to 10th	Day	15% 15% 22% 25% 17% 6%	660
	11th to 20th	Day	13% 17% 24% 24% 17% 5%	526
	21st to end	Day	14% 19% 27% 21% 9% 10%	420
October	1st to 10th	Day	11% 22% 30% 19% 12% 6%	420
	11th to 20th	Day	10% 18% 28% 23% 15% 6%	420
	21st to end	Day	7% 11% 27% 32% 18% 4	462
November	1st to 10th	Day	7% 11% 28% 33% 13% 8%	298
	11th to 20th	Day	4 12% 15% 31% 27% 10%	220
	21st to end	Day	3 10% 27% 23% 22% 14%	181
December	1st to 10th	Day	3 11% 21% 31% 21% 14%	110
	11th to 20th	Day	4 5% 15% 39% 27% 9%	110
	21st to end	Day	3 13% 20% 25% 25% 14%	121
January	1st to 10th	Night	2 8% 24% 35% 26% 7%	982
	11th to 20th	Night	2 10% 30% 33% 20% 4	950
	21st to end	Night	4 9% 31% 31% 19% 6%	1045
February	1st to 10th	Night	2 8% 26% 38% 22% 3	950
	11th to 20th	Night	2 10% 32% 33% 18% 5%	934
	21st to end	Night	3 8% 28% 38% 19% 5%	783
March	1st to 10th	Night	2 7% 27% 33% 24% 8%	914
	11th to 20th	Night	4 8% 24% 32% 21% 12%	642
	21st to end	Night	3 6% 23% 30% 28% 11%	693
April	1st to 10th	Night	4 7% 22% 33% 27% 6%	603
	11th to 20th	Night	6% 6% 23% 30% 29% 7%	593
	21st to end	Night	6% 6% 20% 32% 30% 6%	600
May	1st to 10th	Night	5% 10% 27% 28% 25% 4	488
	11th to 20th	Night	11% 9% 24% 28% 27% 2	377
	21st to end	Night	8% 5% 20% 30% 29% 7%	217
June	1st to 10th	Night	15% 5% 24% 29% 26% 3	200
	11th to 20th	Night	17% 5% 18% 31% 29% 2	200
	21st to end	Night	16% 5% 17% 33% 29% 2	200
July	1st to 10th	Night	17% 2 19% 33% 28% 2	195
	11th to 20th	Night	19% 7% 18% 25% 26% 5%	194
	21st to end	Night	17% 6% 15% 32% 25% 5%	291
August	1st to 10th	Night	11% 7% 21% 31% 25% 4	537
	11th to 20th	Night	18% 8% 22% 26% 19% 7%	594
	21st to end	Night	17% 7% 19% 31% 21% 4	660
September	1st to 10th	Night	17% 12% 22% 28% 17% 4	600
	11th to 20th	Night	11% 10% 23% 32% 20% 4	600
	21st to end	Night	15% 15% 23% 25% 14% 7%	691
October	1st to 10th	Night	12% 15% 27% 29% 14% 4	800
	11th to 20th	Night	12% 11% 24% 30% 18% 5%	874
	21st to end	Night	6% 8% 27% 35% 19% 5%	1001
November	1st to 10th	Night	5% 9% 27% 34% 18% 6%	930
	11th to 20th	Night	4 8% 25% 32% 23% 8%	950
	21st to end	Night	5% 11% 27% 27% 20% 10%	950
December	1st to 10th	Night	3 11% 25% 33% 22% 6%	1150
	11th to 20th	Night	4 7% 22% 35% 23% 8%	1160
	21st to end	Night	4 8% 27% 30% 21% 11%	1276

Page generated at 2026-03-29 22:18:42. Version ac07

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