Burns Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Burns Lake 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	10% 12% 4 10% 6% 6% 5% 4 6% 7% 29%	135386
	Night	10% 14% 5% 11% 6% 6% 5% 4 6% 7% 26%	136459
Transparency	Day	52% 7% 14% 19% 7%	135082
	Night	55% 7% 13% 17% 7%	136341
Seeing	Day	17% 13% 26% 24% 15% 5%	18416
	Night	17% 9% 24% 31% 17% 2	26147

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	10% 19% 7% 18% 8% 6% 5% 4 5% 5% 12%	4125
	11th to 20th	Day	8% 12% 5% 10% 6% 6% 6% 4 7% 8% 28%	4119
	21st to end	Day	11% 21% 6% 12% 6% 5% 5% 4 6% 7% 19%	4529
February	1st to 10th	Day	13% 14% 5% 12% 8% 4 5% 4 5% 5% 23%	1665
	11th to 20th	Day	7% 14% 5% 13% 5% 6% 6% 4 6% 8% 27%	1845
	21st to end	Day	5% 17% 6% 12% 8% 6% 7% 4 4 5% 26%	1557
March	1st to 10th	Day	7% 16% 6% 15% 8% 6% 6% 5% 6% 5% 20%	4615
	11th to 20th	Day	5% 16% 7% 13% 7% 7% 6% 5% 7% 8% 18%	5110
	21st to end	Day	8% 14% 4 9% 5% 5% 6% 4 5% 6% 32%	5607
April	1st to 10th	Day	9% 17% 6% 12% 7% 6% 5% 4 5% 6% 22%	2647
	11th to 20th	Day	9% 16% 5% 11% 7% 6% 5% 4 5% 6% 26%	2698
	21st to end	Day	12% 14% 4 10% 6% 4 5% 4 6% 8% 27%	2821
May	1st to 10th	Day	8% 11% 3 10% 6% 6% 5% 5% 7% 8% 31%	6643
	11th to 20th	Day	10% 13% 5% 11% 7% 7% 6% 5% 6% 7% 24%	6886
	21st to end	Day	11% 12% 4 12% 8% 7% 6% 5% 7% 7% 21%	7570
June	1st to 10th	Day	13% 9% 4 10% 7% 6% 6% 4 6% 7% 29%	3156
	11th to 20th	Day	13% 10% 4 10% 6% 6% 5% 5% 6% 8% 27%	3200
	21st to end	Day	11% 8% 4 10% 7% 6% 5% 5% 6% 7% 32%	3200
July	1st to 10th	Day	8% 5% 2 7% 6% 6% 5% 5% 6% 7% 43%	6829
	11th to 20th	Day	9% 6% 2 6% 4 4 5% 4 6% 9% 44%	6780
	21st to end	Day	8% 5% 2 6% 5% 5% 5% 4 9% 11% 40%	7375
August	1st to 10th	Day	5% 4 2 5% 3 3 4 3 5% 7% 58%	4869
	11th to 20th	Day	12% 7% 3 6% 5% 4 4 3 5% 7% 44%	4202
	21st to end	Day	13% 9% 3 8% 6% 6% 5% 4 6% 7% 34%	4664
September	1st to 10th	Day	12% 7% 3 8% 5% 6% 5% 5% 6% 9% 34%	2505
	11th to 20th	Day	12% 9% 3 10% 6% 6% 6% 5% 6% 8% 31%	2285
	21st to end	Day	17% 12% 4 10% 6% 6% 5% 5% 6% 6% 23%	2186
October	1st to 10th	Day	16% 15% 5% 13% 7% 7% 5% 4 5% 6% 18%	3280
	11th to 20th	Day	14% 12% 4 11% 6% 6% 6% 5% 8% 8% 21%	3143
	21st to end	Day	12% 12% 5% 12% 7% 5% 5% 3 5% 6% 28%	2982
November	1st to 10th	Day	17% 16% 4 10% 6% 7% 4 4 6% 6% 20%	1648
	11th to 20th	Day	12% 19% 6% 10% 7% 6% 6% 4 6% 5% 18%	1596
	21st to end	Day	12% 17% 6% 13% 8% 6% 5% 4 5% 7% 17%	1443
December	1st to 10th	Day	17% 18% 3 11% 8% 7% 6% 3 5% 4 16%	2020
	11th to 20th	Day	15% 21% 7% 16% 7% 6% 6% 4 4 4 11%	2322
	21st to end	Day	6% 21% 8% 15% 7% 7% 6% 5% 5% 5% 15%	3264
January	1st to 10th	Night	11% 21% 7% 16% 8% 6% 5% 4 5% 5% 12%	8770
	11th to 20th	Night	7% 11% 4 9% 6% 6% 5% 4 7% 10% 31%	8779
	21st to end	Night	10% 18% 5% 12% 6% 6% 5% 3 5% 8% 21%	9651
February	1st to 10th	Night	13% 16% 6% 11% 6% 6% 5% 4 5% 5% 22%	2952
	11th to 20th	Night	8% 15% 5% 12% 5% 6% 5% 4 5% 6% 29%	2662
	21st to end	Night	6% 15% 6% 12% 7% 6% 6% 5% 7% 5% 27%	2249
March	1st to 10th	Night	6% 16% 6% 15% 6% 5% 4 3 5% 6% 27%	5482
	11th to 20th	Night	4 12% 6% 13% 8% 7% 7% 6% 7% 7% 23%	5109
	21st to end	Night	8% 14% 3 7% 5% 5% 5% 4 6% 7% 36%	5610
April	1st to 10th	Night	6% 14% 5% 10% 7% 6% 6% 4 7% 7% 29%	1970
	11th to 20th	Night	9% 14% 4 11% 8% 6% 5% 5% 6% 7% 26%	1871
	21st to end	Night	10% 12% 4 9% 7% 4 5% 4 7% 9% 31%	1798
May	1st to 10th	Night	8% 10% 3 8% 7% 7% 8% 5% 7% 9% 29%	3533
	11th to 20th	Night	10% 11% 3 11% 6% 7% 7% 5% 8% 9% 23%	3229
	21st to end	Night	12% 13% 4 11% 7% 5% 5% 4 6% 7% 25%	3547
June	1st to 10th	Night	11% 8% 4 9% 6% 6% 6% 5% 5% 7% 32%	1240
	11th to 20th	Night	14% 10% 4 8% 5% 5% 5% 4 7% 8% 30%	1200
	21st to end	Night	11% 6% 2 7% 5% 5% 7% 5% 6% 9% 35%	1200
July	1st to 10th	Night	9% 6% 2 5% 4 4 4 4 5% 7% 50%	3127
	11th to 20th	Night	9% 6% 2 7% 5% 6% 6% 5% 6% 7% 41%	3180
	21st to end	Night	6% 6% 2 7% 5% 5% 6% 4 8% 9% 42%	3468
August	1st to 10th	Night	4 2 1 4 3 3 3 3 5% 8% 62%	2281
	11th to 20th	Night	9% 7% 3 8% 5% 4 5% 4 5% 7% 44%	2853
	21st to end	Night	13% 9% 3 9% 5% 5% 5% 5% 6% 7% 34%	3245
September	1st to 10th	Night	13% 8% 3 7% 3 4 4 3 6% 7% 41%	1895
	11th to 20th	Night	10% 9% 3 8% 5% 5% 5% 5% 6% 7% 37%	2113
	21st to end	Night	17% 10% 4 8% 6% 5% 6% 5% 6% 6% 28%	2214
October	1st to 10th	Night	20% 14% 4 10% 4 5% 5% 4 4 6% 25%	3920
	11th to 20th	Night	14% 11% 5% 12% 7% 6% 6% 4 6% 6% 22%	4008
	21st to end	Night	16% 15% 4 8% 6% 5% 5% 4 6% 7% 26%	4812
November	1st to 10th	Night	13% 16% 5% 9% 6% 6% 5% 5% 6% 7% 20%	2870
	11th to 20th	Night	11% 18% 6% 11% 7% 6% 6% 5% 6% 7% 18%	3021
	21st to end	Night	10% 18% 6% 12% 8% 6% 5% 4 6% 7% 18%	3154
December	1st to 10th	Night	15% 18% 6% 13% 7% 6% 5% 4 5% 6% 17%	5380
	11th to 20th	Night	12% 23% 7% 14% 6% 6% 5% 4 5% 5% 12%	6090
	21st to end	Night	7% 20% 7% 13% 7% 7% 6% 5% 6% 6% 15%	7976

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	71% 7% 9% 8% 5%	4125
	11th to 20th	Day	52% 6% 16% 16% 7% 3	4140
	21st to end	Day	64% 5% 13% 12% 6%	4530
February	1st to 10th	Day	62% 6% 9% 10% 12% 2	1665
	11th to 20th	Day	55% 7% 13% 18% 6% 1	1854
	21st to end	Day	60% 6% 10% 14% 7% 2	1557
March	1st to 10th	Day	62% 6% 9% 12% 11%	4615
	11th to 20th	Day	59% 6% 10% 16% 8%	5110
	21st to end	Day	49% 7% 11% 24% 9%	5607
April	1st to 10th	Day	61% 5% 11% 17% 5%	2647
	11th to 20th	Day	59% 6% 10% 16% 9%	2698
	21st to end	Day	55% 5% 14% 17% 9%	2821
May	1st to 10th	Day	47% 6% 15% 20% 12%	6643
	11th to 20th	Day	56% 6% 11% 20% 7%	6889
	21st to end	Day	57% 6% 14% 15% 8% 1	7571
June	1st to 10th	Day	52% 6% 11% 22% 8% 1	3156
	11th to 20th	Day	53% 7% 13% 21% 6%	3200
	21st to end	Day	49% 7% 14% 24% 5%	3200
July	1st to 10th	Day	37% 6% 12% 28% 16% 1	6755
	11th to 20th	Day	35% 7% 24% 30% 4	6699
	21st to end	Day	35% 8% 24% 26% 7%	7168
August	1st to 10th	Day	25% 7% 16% 40% 13%	4851
	11th to 20th	Day	38% 7% 15% 32% 7% 1	4242
	21st to end	Day	48% 8% 17% 22% 5%	4663
September	1st to 10th	Day	46% 7% 22% 21% 5%	2505
	11th to 20th	Day	49% 8% 16% 23% 4	2285
	21st to end	Day	58% 9% 12% 17% 4	2186
October	1st to 10th	Day	65% 7% 12% 12% 4	3280
	11th to 20th	Day	57% 8% 19% 12% 3	3143
	21st to end	Day	56% 7% 15% 16% 6% 1	2982
November	1st to 10th	Day	64% 8% 10% 13% 5%	1648
	11th to 20th	Day	66% 8% 10% 12% 4	1596
	21st to end	Day	66% 8% 11% 10% 4	1443
December	1st to 10th	Day	70% 7% 9% 11% 3	2020
	11th to 20th	Day	74% 6% 8% 8% 4	2324
	21st to end	Day	68% 7% 11% 10% 4	3264
January	1st to 10th	Night	71% 8% 6% 8% 6%	8770
	11th to 20th	Night	48% 5% 16% 18% 9% 4	8820
	21st to end	Night	62% 6% 14% 12% 6%	9651
February	1st to 10th	Night	62% 6% 10% 10% 10% 2	2952
	11th to 20th	Night	55% 6% 13% 17% 9%	2664
	21st to end	Night	57% 5% 11% 18% 8% 1	2249
March	1st to 10th	Night	58% 5% 8% 17% 12% 1	5482
	11th to 20th	Night	56% 8% 9% 19% 9%	5110
	21st to end	Night	45% 8% 9% 28% 11%	5610
April	1st to 10th	Night	53% 6% 14% 19% 9%	1970
	11th to 20th	Night	54% 6% 12% 20% 7%	1871
	21st to end	Night	47% 7% 14% 24% 8%	1798
May	1st to 10th	Night	46% 9% 17% 18% 9%	3530
	11th to 20th	Night	53% 9% 15% 18% 4	3229
	21st to end	Night	55% 6% 14% 18% 6%	3547
June	1st to 10th	Night	50% 8% 12% 20% 9% 1	1240
	11th to 20th	Night	50% 7% 12% 24% 6%	1200
	21st to end	Night	43% 9% 19% 25% 4	1200
July	1st to 10th	Night	32% 6% 17% 25% 19% 1	3092
	11th to 20th	Night	38% 8% 23% 28% 3	3138
	21st to end	Night	34% 8% 25% 25% 8%	3370
August	1st to 10th	Night	21% 5% 18% 41% 15%	2274
	11th to 20th	Night	39% 7% 18% 28% 8%	2879
	21st to end	Night	48% 8% 22% 19% 3	3245
September	1st to 10th	Night	43% 6% 22% 23% 6%	1895
	11th to 20th	Night	45% 7% 13% 27% 7%	2113
	21st to end	Night	55% 8% 13% 19% 5%	2214
October	1st to 10th	Night	62% 6% 15% 14% 4	3920
	11th to 20th	Night	59% 7% 14% 17% 3	4008
	21st to end	Night	55% 8% 17% 16% 4	4812
November	1st to 10th	Night	60% 8% 12% 14% 5%	2870
	11th to 20th	Night	64% 8% 12% 12% 4	3021
	21st to end	Night	64% 8% 11% 12% 5%	3154
December	1st to 10th	Night	68% 6% 11% 12% 3	5380
	11th to 20th	Night	72% 7% 8% 9% 4	6087
	21st to end	Night	65% 8% 10% 12% 5%	7976

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	19% 11% 22% 30% 14% 5%	220
	11th to 20th	Day	21% 14% 20% 25% 16% 4	220
	21st to end	Day	22% 7% 26% 24% 16% 5%	242
February	1st to 10th	Day	21% 15% 24% 25% 9% 5%	383
	11th to 20th	Day	15% 14% 28% 26% 13% 4	425
	21st to end	Day	19% 19% 30% 17% 10% 5%	355
March	1st to 10th	Day	17% 18% 27% 22% 13% 4	466
	11th to 20th	Day	16% 14% 30% 23% 14% 3	540
	21st to end	Day	18% 16% 25% 20% 16% 4	594
April	1st to 10th	Day	20% 15% 29% 21% 11% 3	540
	11th to 20th	Day	17% 14% 26% 21% 12% 9%	532
	21st to end	Day	19% 15% 26% 22% 12% 6%	540
May	1st to 10th	Day	16% 16% 29% 24% 13% 3	622
	11th to 20th	Day	17% 12% 27% 21% 18% 5%	775
	21st to end	Day	19% 15% 26% 24% 13% 3	845
June	1st to 10th	Day	18% 14% 25% 26% 14% 3	886
	11th to 20th	Day	16% 11% 26% 29% 15% 4	930
	21st to end	Day	13% 9% 26% 28% 18% 5%	930
July	1st to 10th	Day	14% 9% 25% 27% 18% 6%	744
	11th to 20th	Day	15% 9% 26% 26% 19% 5%	718
	21st to end	Day	11% 12% 25% 28% 16% 8%	794
August	1st to 10th	Day	11% 9% 21% 28% 21% 11%	726
	11th to 20th	Day	12% 11% 25% 27% 18% 7%	521
	21st to end	Day	17% 11% 26% 20% 15% 11%	583
September	1st to 10th	Day	16% 11% 22% 23% 21% 6%	530
	11th to 20th	Day	18% 10% 19% 25% 19% 9%	530
	21st to end	Day	25% 16% 29% 15% 12% 2	530
October	1st to 10th	Day	23% 15% 23% 19% 15% 6%	530
	11th to 20th	Day	24% 15% 26% 20% 11% 4	491
	21st to end	Day	24% 14% 29% 19% 12% 2	332
November	1st to 10th	Day	25% 20% 20% 21% 11% 4	220
	11th to 20th	Day	24% 14% 25% 20% 11% 6%	220
	21st to end	Day	25% 13% 25% 18% 11% 8%	220
December	1st to 10th	Day	15% 9% 23% 31% 18% 5%	220
	11th to 20th	Day	12% 13% 27% 31% 15% 2	220
	21st to end	Day	19% 11% 23% 26% 17% 5%	242
January	1st to 10th	Night	23% 10% 25% 30% 12% 2	950
	11th to 20th	Night	19% 9% 24% 31% 14% 2	950
	21st to end	Night	20% 11% 21% 31% 15% 2	1045
February	1st to 10th	Night	22% 12% 23% 29% 13% 2	933
	11th to 20th	Night	15% 6% 26% 37% 14% 2	824
	21st to end	Night	13% 11% 25% 32% 16% 3	692
March	1st to 10th	Night	16% 12% 23% 29% 17% 2	840
	11th to 20th	Night	13% 11% 28% 31% 16% 1	840
	21st to end	Night	14% 11% 20% 29% 23% 4	924
April	1st to 10th	Night	12% 9% 26% 29% 21% 3	709
	11th to 20th	Night	15% 8% 25% 29% 21% 3	623
	21st to end	Night	14% 11% 25% 33% 15% 1	538
May	1st to 10th	Night	18% 8% 24% 34% 16% 1	420
	11th to 20th	Night	15% 7% 29% 27% 21% 1	414
	21st to end	Night	18% 11% 25% 28% 17% 1	455
June	1st to 10th	Night	14% 7% 27% 35% 16% 1	400
	11th to 20th	Night	17% 8% 28% 37% 10%	400
	21st to end	Night	12% 6% 28% 33% 20% 2	400
July	1st to 10th	Night	14% 7% 26% 29% 21% 2	390
	11th to 20th	Night	14% 6% 24% 33% 20% 2	388
	21st to end	Night	10% 5% 25% 36% 19% 4	438
August	1st to 10th	Night	7% 3 20% 36% 28% 6%	398
	11th to 20th	Night	11% 4 25% 33% 24% 3	561
	21st to end	Night	16% 4 19% 34% 22% 4	660
September	1st to 10th	Night	18% 5% 18% 28% 28% 2	695
	11th to 20th	Night	13% 7% 18% 29% 27% 5%	800
	21st to end	Night	23% 12% 23% 26% 15% 2	800
October	1st to 10th	Night	24% 8% 19% 29% 18% 3	800
	11th to 20th	Night	24% 9% 23% 26% 16% 2	800
	21st to end	Night	26% 9% 23% 30% 12%	880
November	1st to 10th	Night	22% 12% 25% 26% 12% 3	820
	11th to 20th	Night	20% 12% 27% 28% 11% 2	883
	21st to end	Night	19% 10% 28% 28% 13% 3	954
December	1st to 10th	Night	17% 9% 21% 33% 16% 3	1160
	11th to 20th	Night	19% 10% 23% 33% 14% 2	1160
	21st to end	Night	16% 9% 26% 33% 14% 2	1203

Page generated at 2026-05-28 22:53:32. Version ac07

Copyright © 2026 Attilla Danko.