Kirkland Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kirkland Lake clear sky chart from 2005-11-06 to 2025-09-19.

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 9% 5% 5% 5% 3 5% 6% 28%	126766
	Night	16% 14% 5% 11% 6% 5% 4 3 5% 5% 25%	122414
Transparency	Day	58% 3 11% 19% 9% 1	130224
	Night	62% 3 9% 18% 8% 1	127044
Seeing	Day	25% 13% 32% 20% 8% 2	16401
	Night	24% 11% 31% 24% 9% 1	25327

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	10% 20% 10% 19% 8% 9% 6% 3 4 3 9%	3158
	11th to 20th	Day	9% 17% 8% 17% 10% 5% 5% 4 6% 5% 14%	3133
	21st to end	Day	10% 17% 8% 14% 6% 7% 6% 4 6% 6% 16%	4171
February	1st to 10th	Day	7% 17% 6% 13% 8% 8% 7% 5% 5% 6% 18%	1800
	11th to 20th	Day	9% 20% 7% 11% 7% 6% 5% 5% 4 6% 20%	1753
	21st to end	Day	11% 19% 6% 11% 7% 6% 5% 3 3 5% 23%	1485
March	1st to 10th	Day	17% 16% 4 11% 6% 4 5% 3 5% 5% 23%	4815
	11th to 20th	Day	17% 16% 5% 13% 7% 5% 3 3 4 4 24%	4980
	21st to end	Day	14% 17% 5% 11% 5% 6% 5% 3 4 4 26%	5465
April	1st to 10th	Day	19% 16% 5% 11% 4 4 4 3 5% 5% 23%	2382
	11th to 20th	Day	20% 13% 4 8% 5% 3 4 3 4 5% 31%	2572
	21st to end	Day	21% 13% 3 7% 5% 4 4 3 4 4 32%	2600
May	1st to 10th	Day	17% 11% 3 7% 4 4 4 3 4 5% 37%	6181
	11th to 20th	Day	13% 8% 3 8% 5% 5% 5% 4 6% 7% 37%	6318
	21st to end	Day	20% 10% 2 6% 4 4 4 3 4 6% 36%	7241
June	1st to 10th	Day	20% 9% 3 7% 5% 5% 5% 4 6% 7% 29%	3000
	11th to 20th	Day	16% 7% 3 7% 5% 5% 5% 4 6% 8% 35%	3000
	21st to end	Day	21% 8% 2 7% 5% 4 6% 4 6% 7% 29%	3000
July	1st to 10th	Day	15% 7% 3 7% 5% 5% 6% 4 8% 10% 30%	6819
	11th to 20th	Day	16% 6% 2 6% 4 4 5% 4 7% 9% 36%	6820
	21st to end	Day	16% 7% 2 6% 4 4 5% 4 6% 9% 36%	7210
August	1st to 10th	Day	15% 6% 3 7% 5% 5% 5% 4 6% 8% 35%	4244
	11th to 20th	Day	18% 8% 3 7% 4 4 5% 4 6% 7% 35%	4174
	21st to end	Day	16% 6% 3 7% 4 4 5% 4 6% 8% 37%	4647
September	1st to 10th	Day	21% 7% 3 7% 5% 4 5% 3 6% 7% 32%	2400
	11th to 20th	Day	22% 8% 2 7% 4 4 4 3 5% 7% 33%	2258
	21st to end	Day	24% 10% 3 6% 5% 4 3 3 5% 6% 31%	2058
October	1st to 10th	Day	22% 12% 3 8% 5% 3 4 3 5% 6% 29%	1900
	11th to 20th	Day	28% 19% 4 7% 5% 4 3 2 4 5% 18%	1900
	21st to end	Day	27% 22% 5% 9% 6% 4 4 3 3 4 14%	1964
November	1st to 10th	Day	23% 21% 6% 8% 5% 4 3 2 5% 5% 19%	1566
	11th to 20th	Day	20% 21% 6% 15% 7% 5% 3 2 4 4 12%	1600
	21st to end	Day	24% 21% 8% 15% 5% 5% 3 3 4 3 9%	1600
December	1st to 10th	Day	15% 22% 12% 20% 8% 4 3 2 3 3 8%	2455
	11th to 20th	Day	13% 20% 8% 15% 7% 6% 4 3 4 3 18%	2621
	21st to end	Day	18% 24% 9% 16% 7% 4 3 3 4 4 8%	3476
January	1st to 10th	Night	9% 19% 10% 19% 9% 7% 5% 3 4 4 11%	6808
	11th to 20th	Night	11% 17% 7% 17% 8% 7% 6% 5% 6% 4 13%	6772
	21st to end	Night	8% 18% 9% 15% 7% 6% 7% 4 4 4 18%	6790
February	1st to 10th	Night	10% 15% 5% 11% 10% 6% 6% 5% 6% 7% 19%	2600
	11th to 20th	Night	11% 17% 6% 13% 8% 6% 6% 3 4 6% 21%	2533
	21st to end	Night	10% 16% 6% 14% 8% 6% 5% 4 5% 6% 20%	2140
March	1st to 10th	Night	18% 16% 5% 10% 6% 4 4 3 3 5% 26%	5024
	11th to 20th	Night	18% 17% 7% 13% 8% 5% 4 3 4 4 19%	4979
	21st to end	Night	15% 15% 5% 11% 6% 5% 4 3 4 5% 25%	5467
April	1st to 10th	Night	19% 16% 4 10% 5% 4 3 3 5% 5% 27%	2026
	11th to 20th	Night	19% 11% 3 8% 5% 5% 4 3 5% 5% 31%	1787
	21st to end	Night	19% 10% 4 6% 4 4 4 3 5% 5% 35%	1800
May	1st to 10th	Night	17% 11% 3 7% 4 5% 5% 3 4 5% 36%	3760
	11th to 20th	Night	13% 7% 2 6% 4 4 4 3 5% 7% 43%	3575
	21st to end	Night	16% 9% 3 6% 3 4 5% 4 5% 7% 37%	3632
June	1st to 10th	Night	21% 10% 3 6% 4 5% 4 4 6% 7% 31%	1400
	11th to 20th	Night	17% 7% 2 6% 4 3 4 4 5% 7% 42%	1400
	21st to end	Night	17% 8% 2 7% 5% 4 5% 4 5% 7% 37%	1400
July	1st to 10th	Night	17% 8% 3 7% 5% 4 4 4 6% 5% 38%	3160
	11th to 20th	Night	18% 7% 2 6% 4 4 4 3 5% 7% 38%	3160
	21st to end	Night	14% 6% 2 6% 4 4 4 3 6% 7% 45%	3652
August	1st to 10th	Night	10% 6% 2 6% 5% 5% 5% 5% 7% 8% 42%	2901
	11th to 20th	Night	16% 7% 3 6% 5% 4 5% 4 5% 7% 39%	2875
	21st to end	Night	16% 6% 3 7% 5% 3 3 3 4 6% 45%	3223
September	1st to 10th	Night	18% 7% 3 7% 4 5% 4 4 5% 6% 38%	1995
	11th to 20th	Night	17% 9% 2 6% 3 3 4 3 4 7% 41%	2097
	21st to end	Night	21% 9% 2 6% 3 4 4 3 4 6% 38%	2121
October	1st to 10th	Night	22% 12% 2 8% 4 3 4 3 5% 6% 31%	2280
	11th to 20th	Night	27% 17% 4 8% 5% 5% 3 3 4 5% 19%	2280
	21st to end	Night	23% 19% 4 9% 5% 4 4 3 4 5% 20%	2631
November	1st to 10th	Night	19% 17% 6% 9% 5% 4 5% 3 4 5% 21%	2732
	11th to 20th	Night	21% 18% 6% 14% 7% 5% 3 3 4 4 16%	2800
	21st to end	Night	23% 21% 8% 13% 6% 5% 4 2 3 4 11%	2800
December	1st to 10th	Night	13% 23% 8% 18% 10% 7% 4 3 4 2 7%	4726
	11th to 20th	Night	14% 20% 8% 13% 9% 7% 5% 3 4 4 13%	5586
	21st to end	Night	21% 20% 8% 13% 6% 4 3 2 4 4 14%	7502

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	83% 1 6% 7% 3	3159
	11th to 20th	Day	71% 3 6% 13% 7%	3160
	21st to end	Day	70% 1 6% 15% 7%	4171
February	1st to 10th	Day	66% 4 8% 15% 7%	1800
	11th to 20th	Day	65% 3 8% 15% 8%	1762
	21st to end	Day	65% 2 5% 18% 8% 1	1485
March	1st to 10th	Day	64% 2 6% 14% 12% 2	4818
	11th to 20th	Day	66% 2 10% 15% 7% 1	4980
	21st to end	Day	62% 3 7% 18% 9% 2	5465
April	1st to 10th	Day	63% 3 7% 16% 11%	2382
	11th to 20th	Day	55% 3 7% 22% 11% 1	2572
	21st to end	Day	57% 2 9% 16% 14% 2	2600
May	1st to 10th	Day	49% 3 7% 18% 20% 2	6191
	11th to 20th	Day	47% 3 15% 20% 11% 3	6322
	21st to end	Day	50% 3 9% 19% 16% 2	7241
June	1st to 10th	Day	52% 4 10% 24% 9% 1	3000
	11th to 20th	Day	47% 4 11% 23% 15% 1	3000
	21st to end	Day	53% 3 12% 21% 10% 1	3000
July	1st to 10th	Day	48% 3 16% 26% 6%	6746
	11th to 20th	Day	45% 2 19% 27% 7%	6739
	21st to end	Day	46% 2 12% 32% 7%	7004
August	1st to 10th	Day	47% 3 16% 27% 6%	4230
	11th to 20th	Day	49% 4 13% 28% 6% 1	4213
	21st to end	Day	46% 3 12% 30% 7% 2	4647
September	1st to 10th	Day	52% 4 14% 22% 8%	2400
	11th to 20th	Day	50% 4 17% 24% 5%	2258
	21st to end	Day	55% 4 12% 22% 7% 1	2058
October	1st to 10th	Day	61% 2 10% 20% 7%	3160
	11th to 20th	Day	62% 2 11% 19% 7%	3140
	21st to end	Day	71% 2 13% 7% 7%	3203
November	1st to 10th	Day	69% 3 13% 11% 4	1566
	11th to 20th	Day	78% 2 7% 9% 3	1600
	21st to end	Day	81% 3 8% 6% 2	1600
December	1st to 10th	Day	84% 1 6% 6% 2	2455
	11th to 20th	Day	72% 2 8% 15% 2	2621
	21st to end	Day	81% 1 3 10% 4	3476
January	1st to 10th	Night	79% 2 10% 7% 2 1	6808
	11th to 20th	Night	73% 2 6% 12% 7%	6820
	21st to end	Night	72% 1 4 14% 8%	6790
February	1st to 10th	Night	63% 3 10% 15% 9%	2600
	11th to 20th	Night	66% 3 9% 15% 7%	2535
	21st to end	Night	66% 3 8% 15% 8% 1	2140
March	1st to 10th	Night	64% 2 7% 13% 10% 4	5034
	11th to 20th	Night	71% 3 7% 12% 6% 1	4980
	21st to end	Night	62% 3 5% 16% 11% 3	5467
April	1st to 10th	Night	59% 3 6% 18% 13% 1	2026
	11th to 20th	Night	55% 3 6% 20% 15% 2	1787
	21st to end	Night	52% 2 8% 16% 19% 2	1800
May	1st to 10th	Night	51% 4 7% 19% 19% 1	3766
	11th to 20th	Night	41% 3 14% 25% 14% 2	3576
	21st to end	Night	46% 4 11% 20% 16% 3	3633
June	1st to 10th	Night	52% 3 9% 22% 12% 2	1400
	11th to 20th	Night	41% 4 12% 26% 15% 2	1400
	21st to end	Night	47% 3 14% 21% 13% 2	1400
July	1st to 10th	Night	48% 2 12% 28% 10%	3125
	11th to 20th	Night	46% 3 13% 29% 9%	3118
	21st to end	Night	40% 2 17% 34% 7%	3544
August	1st to 10th	Night	39% 3 16% 34% 7%	2891
	11th to 20th	Night	45% 3 14% 32% 5%	2902
	21st to end	Night	43% 2 14% 30% 11% 1	3223
September	1st to 10th	Night	47% 4 16% 23% 8% 1	1995
	11th to 20th	Night	44% 4 18% 27% 7%	2097
	21st to end	Night	48% 4 15% 26% 8%	2121
October	1st to 10th	Night	54% 2 10% 24% 9%	3800
	11th to 20th	Night	61% 3 10% 21% 4	3779
	21st to end	Night	63% 3 14% 13% 6%	4342
November	1st to 10th	Night	65% 4 12% 16% 3	2732
	11th to 20th	Night	73% 3 10% 10% 3	2800
	21st to end	Night	79% 4 8% 7% 2	2800
December	1st to 10th	Night	84% 2 5% 7% 2	4726
	11th to 20th	Night	76% 2 6% 11% 5%	5585
	21st to end	Night	76% 1 5% 12% 5%	7502

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% 18% 37% 17% 4 1	200
	11th to 20th	Day	26% 12% 32% 23% 8% 1	200
	21st to end	Day	22% 11% 39% 22% 5% 1	315
February	1st to 10th	Day	21% 22% 39% 14% 2 1	300
	11th to 20th	Day	20% 23% 40% 12% 3 1	300
	21st to end	Day	29% 21% 37% 11% 2	249
March	1st to 10th	Day	22% 17% 40% 17% 4	444
	11th to 20th	Day	28% 16% 34% 17% 4	500
	21st to end	Day	29% 17% 34% 15% 4 1	550
April	1st to 10th	Day	27% 20% 25% 18% 7% 2	500
	11th to 20th	Day	31% 14% 29% 17% 6% 3	492
	21st to end	Day	34% 15% 29% 13% 7% 2	500
May	1st to 10th	Day	25% 12% 34% 19% 9% 1	503
	11th to 20th	Day	25% 11% 34% 20% 7% 3	527
	21st to end	Day	25% 11% 33% 23% 7% 1	696
June	1st to 10th	Day	24% 10% 38% 20% 7% 1	730
	11th to 20th	Day	21% 13% 34% 23% 7% 1	730
	21st to end	Day	25% 10% 29% 25% 9% 2	730
July	1st to 10th	Day	18% 12% 33% 27% 8% 2	721
	11th to 20th	Day	17% 10% 34% 27% 10% 2	718
	21st to end	Day	19% 6% 31% 29% 11% 4	704
August	1st to 10th	Day	19% 7% 29% 27% 14% 3	526
	11th to 20th	Day	19% 8% 26% 26% 15% 7%	519
	21st to end	Day	22% 8% 29% 23% 12% 6%	583
September	1st to 10th	Day	24% 9% 32% 21% 12% 3	530
	11th to 20th	Day	23% 9% 28% 25% 11% 4	522
	21st to end	Day	29% 10% 26% 20% 14% 1	490
October	1st to 10th	Day	29% 11% 28% 22% 8% 2	490
	11th to 20th	Day	37% 13% 30% 14% 4 2	490
	21st to end	Day	35% 16% 32% 14% 2 1	422
November	1st to 10th	Day	38% 16% 36% 8% 3	200
	11th to 20th	Day	32% 17% 34% 14% 4	200
	21st to end	Day	42% 14% 32% 8% 4 1	200
December	1st to 10th	Day	24% 13% 41% 14% 8% 2	200
	11th to 20th	Day	23% 18% 38% 17% 4 1	200
	21st to end	Day	31% 14% 31% 16% 6% 1	220
January	1st to 10th	Night	24% 13% 38% 18% 6% 1	1000
	11th to 20th	Night	25% 11% 35% 22% 6% 1	1000
	21st to end	Night	19% 10% 32% 28% 11% 1	981
February	1st to 10th	Night	18% 13% 38% 23% 8%	800
	11th to 20th	Night	21% 14% 36% 24% 5%	783
	21st to end	Night	20% 16% 37% 20% 6%	660
March	1st to 10th	Night	20% 17% 33% 23% 6% 1	800
	11th to 20th	Night	26% 15% 33% 20% 6%	800
	21st to end	Night	21% 14% 37% 21% 6% 1	880
April	1st to 10th	Night	28% 14% 30% 23% 5% 1	800
	11th to 20th	Night	24% 15% 27% 24% 9% 1	603
	21st to end	Night	27% 9% 33% 23% 7% 1	600
May	1st to 10th	Night	23% 8% 32% 29% 7%	475
	11th to 20th	Night	23% 9% 31% 27% 9% 2	394
	21st to end	Night	21% 9% 31% 33% 5%	433
June	1st to 10th	Night	24% 7% 32% 28% 10%	400
	11th to 20th	Night	21% 7% 33% 28% 11% 1	400
	21st to end	Night	21% 5% 27% 35% 12% 1	400
July	1st to 10th	Night	19% 6% 29% 34% 10% 1	390
	11th to 20th	Night	17% 4 30% 34% 14% 1	388
	21st to end	Night	14% 3 30% 38% 14% 1	438
August	1st to 10th	Night	14% 3 31% 30% 20% 2	583
	11th to 20th	Night	18% 4 23% 32% 20% 3	594
	21st to end	Night	23% 4 25% 30% 16% 2	660
September	1st to 10th	Night	23% 9% 26% 27% 13% 1	795
	11th to 20th	Night	23% 6% 25% 29% 16% 2	793
	21st to end	Night	26% 6% 26% 27% 13% 1	760
October	1st to 10th	Night	29% 9% 29% 25% 7% 1	760
	11th to 20th	Night	36% 11% 28% 18% 7% 1	760
	21st to end	Night	33% 10% 31% 20% 5% 1	836
November	1st to 10th	Night	27% 12% 35% 20% 5% 1	780
	11th to 20th	Night	30% 16% 30% 17% 6% 1	800
	21st to end	Night	35% 13% 32% 15% 4 1	800
December	1st to 10th	Night	28% 12% 33% 21% 7%	881
	11th to 20th	Night	26% 14% 35% 18% 6% 1	1000
	21st to end	Night	30% 13% 29% 20% 7% 2	1100

Page generated at 2025-09-16 01:49:11. Version ac07

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