Lake of the Woods
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake of the Woods clear sky chart from 2005-11-06 to 2025-04-26.

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% 11% 3 7% 4 3 4 3 4 6% 49%	117809
	Night	6% 10% 4 9% 5% 4 4 3 4 5% 45%	119657
Transparency	Day	35% 5% 8% 20% 20% 12%	117557
	Night	39% 6% 8% 19% 19% 10%	119498
Seeing	Day	19% 16% 27% 22% 13% 3	15403
	Night	18% 10% 18% 30% 20% 3	24638

By Month

Percentage Cloud Cover SW (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	9% 23% 9% 10% 7% 5% 5% 4 4 5% 20%	3639
	11th to 20th	Day	10% 14% 5% 8% 4 2 3 2 4 4 43%	3756
	21st to end	Day	9% 17% 3 6% 3 3 3 2 4 5% 44%	4510
February	1st to 10th	Day	8% 16% 5% 12% 5% 4 5% 4 6% 7% 28%	1800
	11th to 20th	Day	5% 18% 7% 11% 5% 5% 4 3 5% 6% 30%	1755
	21st to end	Day	8% 18% 7% 12% 6% 4 5% 2 4 6% 29%	1640
March	1st to 10th	Day	6% 19% 7% 14% 5% 3 4 2 4 6% 30%	4736
	11th to 20th	Day	6% 17% 6% 11% 6% 5% 4 3 4 4 35%	5000
	21st to end	Day	5% 23% 6% 14% 7% 5% 4 3 4 6% 23%	5615
April	1st to 10th	Day	9% 19% 6% 11% 5% 5% 4 3 4 5% 29%	2400
	11th to 20th	Day	9% 15% 5% 9% 5% 4 4 3 4 7% 35%	2369
	21st to end	Day	5% 14% 4 8% 5% 4 4 4 7% 7% 38%	2403
May	1st to 10th	Day	7% 14% 3 7% 4 4 3 3 4 5% 46%	4233
	11th to 20th	Day	5% 6% 2 5% 2 2 3 3 4 6% 62%	4377
	21st to end	Day	6% 7% 2 5% 4 4 4 4 5% 8% 52%	4813
June	1st to 10th	Day	10% 8% 2 6% 4 4 5% 3 6% 9% 43%	2660
	11th to 20th	Day	4 5% 2 5% 4 4 4 4 4 7% 58%	2660
	21st to end	Day	4 4 1 4 3 2 3 2 4 5% 69%	2660
July	1st to 10th	Day	1 1 1 1 1 1 1 2 3 87%	4420
	11th to 20th	Day	2 2 1 2 2 2 3 2 3 3 78%	4420
	21st to end	Day	1 1 1 1 1 2 2 2 3 86%	4648
August	1st to 10th	Day	3 3 1 3 2 2 2 3 4 4 72%	4091
	11th to 20th	Day	2 1 2 2 2 2 2 4 5% 77%	4007
	21st to end	Day	2 3 1 4 2 2 2 2 2 3 77%	4180
September	1st to 10th	Day	1 1 1 3 2 2 3 2 3 6% 77%	2280
	11th to 20th	Day	4 4 2 5% 3 3 4 3 5% 6% 59%	2280
	21st to end	Day	4 5% 2 6% 2 3 3 3 4 6% 61%	2012
October	1st to 10th	Day	4 4 1 3 3 2 3 2 4 5% 69%	3180
	11th to 20th	Day	5% 6% 2 7% 4 4 5% 4 7% 8% 48%	3161
	21st to end	Day	7% 11% 4 10% 5% 4 5% 3 5% 6% 40%	3448
November	1st to 10th	Day	11% 13% 4 8% 5% 5% 5% 3 5% 7% 33%	1769
	11th to 20th	Day	9% 16% 5% 10% 6% 5% 5% 4 6% 8% 27%	1635
	21st to end	Day	7% 16% 4 11% 5% 4 5% 3 7% 6% 33%	1600
December	1st to 10th	Day	5% 9% 3 7% 5% 4 4 4 5% 7% 47%	2620
	11th to 20th	Day	11% 20% 6% 14% 6% 4 5% 3 5% 7% 19%	3028
	21st to end	Day	12% 17% 6% 14% 8% 7% 6% 4 6% 6% 15%	4004
January	1st to 10th	Night	8% 19% 6% 14% 9% 7% 5% 4 5% 5% 18%	6306
	11th to 20th	Night	6% 14% 5% 10% 4 4 3 2 3 4 45%	6205
	21st to end	Night	9% 15% 4 9% 5% 4 3 2 3 4 38%	6468
February	1st to 10th	Night	8% 13% 5% 11% 6% 5% 5% 4 5% 7% 31%	2600
	11th to 20th	Night	7% 15% 5% 11% 7% 6% 6% 4 4 6% 31%	2532
	21st to end	Night	5% 14% 5% 13% 7% 6% 6% 4 5% 5% 31%	1988
March	1st to 10th	Night	4 14% 8% 14% 7% 5% 5% 3 6% 6% 27%	5156
	11th to 20th	Night	4 13% 6% 13% 7% 6% 4 3 4 4 35%	5000
	21st to end	Night	4 14% 7% 14% 10% 8% 6% 4 4 6% 23%	5359
April	1st to 10th	Night	10% 14% 4 10% 6% 5% 6% 4 6% 7% 28%	2000
	11th to 20th	Night	5% 12% 5% 10% 5% 5% 4 3 4 7% 39%	1979
	21st to end	Night	6% 12% 5% 8% 5% 6% 3 4 6% 9% 36%	1891
May	1st to 10th	Night	6% 12% 7% 7% 4 3 3 2 5% 5% 47%	2732
	11th to 20th	Night	4 4 1 5% 3 4 3 3 4 5% 65%	2516
	21st to end	Night	4 8% 2 5% 3 4 5% 4 6% 7% 53%	2762
June	1st to 10th	Night	10% 9% 3 6% 5% 3 4 4 6% 8% 44%	1520
	11th to 20th	Night	3 4 2 5% 5% 4 4 4 5% 8% 58%	1520
	21st to end	Night	4 3 1 3 2 3 2 2 3 5% 72%	1520
July	1st to 10th	Night	1 1 1 1 1 1 2 2 3 86%	2540
	11th to 20th	Night	2 2 3 3 2 2 2 3 4 78%	2540
	21st to end	Night	1 1 2 2 2 2 2 3 3 82%	2906
August	1st to 10th	Night	2 2 1 3 2 2 2 2 5% 5% 74%	2848
	11th to 20th	Night	1 2 1 2 2 2 2 2 3 4 80%	2830
	21st to end	Night	5% 3 1 3 1 2 1 1 2 3 78%	3498
September	1st to 10th	Night	2 1 2 1 2 2 2 4 5% 80%	1900
	11th to 20th	Night	3 4 2 4 3 3 3 3 5% 6% 64%	1900
	21st to end	Night	6% 4 2 4 2 2 2 2 3 6% 65%	2164
October	1st to 10th	Night	3 3 1 4 4 3 2 2 3 4 71%	3800
	11th to 20th	Night	6% 6% 2 7% 4 4 3 2 4 7% 54%	3777
	21st to end	Night	5% 6% 4 10% 7% 6% 6% 4 5% 7% 40%	4121
November	1st to 10th	Night	12% 11% 4 9% 7% 6% 5% 3 4 6% 34%	2528
	11th to 20th	Night	10% 13% 5% 10% 8% 6% 6% 4 6% 8% 25%	2763
	21st to end	Night	7% 14% 4 10% 6% 5% 5% 3 4 6% 36%	2800
December	1st to 10th	Night	6% 8% 3 6% 4 4 5% 3 5% 7% 48%	4560
	11th to 20th	Night	8% 19% 7% 15% 7% 6% 5% 4 4 5% 19%	5176
	21st to end	Night	13% 16% 7% 13% 7% 5% 4 3 4 5% 22%	6952

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% 6% 8% 13% 8% 1	3639
	11th to 20th	Day	46% 3 5% 18% 23% 5%	3756
	21st to end	Day	43% 4 8% 11% 18% 15%	4510
February	1st to 10th	Day	50% 9% 11% 17% 11% 2	1800
	11th to 20th	Day	52% 6% 10% 16% 13% 3	1764
	21st to end	Day	54% 7% 8% 15% 12% 4	1640
March	1st to 10th	Day	53% 5% 7% 20% 13% 3	4736
	11th to 20th	Day	51% 4 9% 18% 16% 1	5000
	21st to end	Day	58% 8% 10% 19% 4	5615
April	1st to 10th	Day	54% 7% 10% 17% 10% 2	2400
	11th to 20th	Day	46% 7% 12% 19% 13% 3	2372
	21st to end	Day	39% 8% 13% 25% 13% 2	2403
May	1st to 10th	Day	34% 8% 9% 26% 22% 1	4233
	11th to 20th	Day	22% 5% 7% 22% 37% 7%	4380
	21st to end	Day	27% 6% 15% 38% 12% 1	4814
June	1st to 10th	Day	34% 8% 13% 27% 17% 1	2660
	11th to 20th	Day	22% 8% 9% 33% 22% 6%	2660
	21st to end	Day	18% 3 6% 27% 32% 13%	2660
July	1st to 10th	Day	7% 2 4 12% 19% 56%	4351
	11th to 20th	Day	12% 3 3 11% 21% 49%	4345
	21st to end	Day	7% 2 2 15% 38% 36%	4501
August	1st to 10th	Day	16% 3 3 14% 28% 35%	4076
	11th to 20th	Day	11% 3 4 24% 41% 18%	4046
	21st to end	Day	14% 2 4 27% 32% 21%	4179
September	1st to 10th	Day	10% 3 3 18% 33% 32%	2280
	11th to 20th	Day	22% 5% 7% 23% 30% 14%	2280
	21st to end	Day	22% 5% 7% 23% 27% 15%	2012
October	1st to 10th	Day	19% 3 8% 14% 32% 24%	3180
	11th to 20th	Day	29% 5% 15% 29% 17% 5%	3161
	21st to end	Day	41% 5% 8% 22% 20% 5%	3448
November	1st to 10th	Day	47% 6% 10% 19% 15% 3	1769
	11th to 20th	Day	53% 7% 13% 12% 10% 4	1635
	21st to end	Day	48% 6% 10% 15% 16% 6%	1600
December	1st to 10th	Day	35% 4 6% 20% 24% 11%	2620
	11th to 20th	Day	62% 5% 13% 14% 5% 1	3028
	21st to end	Day	67% 6% 8% 13% 6% 1	4004
January	1st to 10th	Night	62% 7% 9% 12% 9% 1	6306
	11th to 20th	Night	43% 5% 5% 16% 23% 8%	6205
	21st to end	Night	50% 4 5% 9% 17% 16%	6468
February	1st to 10th	Night	49% 7% 10% 17% 14% 2	2600
	11th to 20th	Night	50% 8% 9% 17% 13% 3	2534
	21st to end	Night	49% 9% 12% 15% 12% 4	1988
March	1st to 10th	Night	51% 8% 8% 19% 10% 4	5156
	11th to 20th	Night	49% 5% 10% 20% 16%	5000
	21st to end	Night	56% 9% 13% 16% 6%	5359
April	1st to 10th	Night	50% 8% 14% 18% 9% 1	2000
	11th to 20th	Night	41% 8% 13% 19% 15% 4	1979
	21st to end	Night	39% 10% 14% 21% 14% 1	1891
May	1st to 10th	Night	36% 7% 9% 26% 17% 5%	2732
	11th to 20th	Night	20% 5% 8% 27% 37% 3	2516
	21st to end	Night	22% 9% 17% 40% 12% 1	2762
June	1st to 10th	Night	36% 7% 14% 26% 16% 2	1520
	11th to 20th	Night	20% 7% 11% 32% 22% 6%	1520
	21st to end	Night	16% 3 7% 31% 33% 10%	1520
July	1st to 10th	Night	6% 2 5% 13% 17% 57%	2500
	11th to 20th	Night	12% 2 2 13% 23% 47%	2492
	21st to end	Night	9% 3 2 15% 38% 33%	2815
August	1st to 10th	Night	14% 3 4 17% 32% 31%	2839
	11th to 20th	Night	10% 3 3 29% 36% 20%	2857
	21st to end	Night	14% 2 6% 30% 29% 20%	3498
September	1st to 10th	Night	7% 4 3 19% 36% 31%	1900
	11th to 20th	Night	19% 6% 8% 22% 30% 16%	1900
	21st to end	Night	20% 5% 7% 25% 24% 19%	2164
October	1st to 10th	Night	17% 4 6% 17% 32% 23%	3800
	11th to 20th	Night	29% 5% 11% 31% 18% 6%	3777
	21st to end	Night	37% 5% 10% 23% 18% 7%	4121
November	1st to 10th	Night	46% 8% 10% 15% 15% 5%	2528
	11th to 20th	Night	52% 9% 10% 12% 13% 4	2763
	21st to end	Night	47% 7% 9% 14% 15% 8%	2800
December	1st to 10th	Night	33% 4 6% 17% 29% 10%	4560
	11th to 20th	Night	63% 6% 9% 14% 7% 1	5176
	21st to end	Night	62% 6% 10% 11% 9% 1	6952

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	35% 22% 24% 14% 6%	200
	11th to 20th	Day	31% 18% 23% 18% 7% 2	251
	21st to end	Day	27% 18% 20% 23% 11% 1	440
February	1st to 10th	Day	29% 20% 27% 19% 5%	400
	11th to 20th	Day	32% 22% 22% 16% 7%	395
	21st to end	Day	29% 19% 27% 18% 7%	409
March	1st to 10th	Day	32% 21% 26% 16% 4 1	500
	11th to 20th	Day	29% 18% 25% 17% 10% 1	500
	21st to end	Day	33% 23% 25% 15% 4 1	550
April	1st to 10th	Day	27% 24% 23% 18% 7% 2	500
	11th to 20th	Day	28% 20% 27% 16% 6% 2	492
	21st to end	Day	21% 23% 28% 17% 9% 2	481
May	1st to 10th	Day	22% 18% 30% 20% 8% 2	463
	11th to 20th	Day	25% 17% 24% 20% 10% 3	488
	21st to end	Day	21% 15% 24% 23% 13% 4	529
June	1st to 10th	Day	18% 17% 27% 21% 14% 3	490
	11th to 20th	Day	16% 21% 31% 19% 12% 1	490
	21st to end	Day	6% 14% 31% 28% 17% 5%	490
July	1st to 10th	Day	6% 13% 35% 28% 14% 5%	486
	11th to 20th	Day	3 12% 34% 29% 17% 6%	484
	21st to end	Day	3 7% 34% 29% 20% 7%	531
August	1st to 10th	Day	2 10% 32% 28% 20% 8%	487
	11th to 20th	Day	5% 11% 28% 27% 20% 9%	477
	21st to end	Day	6% 10% 28% 30% 21% 6%	539
September	1st to 10th	Day	2 12% 29% 31% 20% 5%	490
	11th to 20th	Day	12% 12% 27% 29% 18% 3	490
	21st to end	Day	10% 15% 27% 30% 15% 2	490
October	1st to 10th	Day	15% 14% 27% 25% 16% 2	490
	11th to 20th	Day	18% 13% 23% 26% 18% 2	490
	21st to end	Day	23% 15% 27% 18% 14% 2	539
November	1st to 10th	Day	27% 13% 20% 25% 14%	305
	11th to 20th	Day	27% 9% 29% 20% 12% 3	217
	21st to end	Day	24% 19% 20% 23% 14% 1	200
December	1st to 10th	Day	27% 10% 28% 22% 8% 5%	200
	11th to 20th	Day	35% 17% 22% 15% 12% 1	200
	21st to end	Day	31% 20% 21% 21% 5% 1	220
January	1st to 10th	Night	29% 15% 21% 21% 11% 3	800
	11th to 20th	Night	24% 14% 18% 25% 15% 3	800
	21st to end	Night	24% 11% 17% 26% 17% 4	880
February	1st to 10th	Night	24% 12% 23% 29% 11% 2	800
	11th to 20th	Night	22% 16% 20% 26% 15% 1	784
	21st to end	Night	21% 16% 23% 30% 11% 1	660
March	1st to 10th	Night	24% 17% 21% 25% 11% 2	800
	11th to 20th	Night	23% 14% 16% 28% 17% 2	800
	21st to end	Night	25% 17% 22% 24% 11% 1	880
April	1st to 10th	Night	25% 14% 20% 26% 14% 2	800
	11th to 20th	Night	18% 17% 23% 24% 15% 3	791
	21st to end	Night	18% 14% 20% 29% 17% 2	719
May	1st to 10th	Night	14% 10% 24% 30% 20% 2	494
	11th to 20th	Night	13% 9% 20% 34% 22% 3	374
	21st to end	Night	15% 9% 18% 32% 23% 2	411
June	1st to 10th	Night	17% 6% 18% 33% 23% 3	380
	11th to 20th	Night	7% 6% 23% 39% 23% 2	380
	21st to end	Night	7% 3 14% 44% 31% 2	380
July	1st to 10th	Night	4 2 12% 47% 34% 2	370
	11th to 20th	Night	2 1 17% 49% 30% 1	368
	21st to end	Night	1 1 11% 41% 40% 5%	499
August	1st to 10th	Night	3 1 9% 41% 39% 8%	567
	11th to 20th	Night	3 2 10% 34% 43% 9%	569
	21st to end	Night	4 3 18% 40% 30% 4	836
September	1st to 10th	Night	3 4 17% 39% 32% 5%	760
	11th to 20th	Night	7% 5% 16% 33% 33% 7%	760
	21st to end	Night	11% 6% 13% 34% 30% 6%	760
October	1st to 10th	Night	8% 8% 18% 34% 28% 4	760
	11th to 20th	Night	15% 8% 12% 33% 27% 5%	760
	21st to end	Night	18% 9% 18% 29% 20% 6%	836
November	1st to 10th	Night	23% 10% 20% 26% 16% 4	780
	11th to 20th	Night	27% 11% 18% 28% 15% 2	800
	21st to end	Night	22% 13% 18% 27% 18% 3	800
December	1st to 10th	Night	23% 10% 18% 30% 16% 3	800
	11th to 20th	Night	28% 12% 20% 26% 12% 2	800
	21st to end	Night	34% 15% 19% 24% 7% 1	880

Page generated at 2025-04-23 06:25:07. Version ac07

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