Balsam Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Balsam Lake clear sky chart from 2005-11-06 to 2024-04-10.

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	13% 9% 4 7% 6% 3 5% 5% 5% 7% 35%	83084
	Night	12% 9% 4 8% 6% 3 5% 5% 5% 6% 36%	85763
Transparency	Day	47% 7% 13% 22% 9% 1	82784
	Night	47% 6% 12% 22% 11% 1	85583
Seeing	Day	16% 10% 31% 26% 13% 4	15138
	Night	16% 9% 33% 31% 10% 1	25244

By Month

Percentage Cloud Cover SE (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	12% 14% 6% 15% 8% 3 5% 4 4 6% 21%	2527
	11th to 20th	Day	6% 9% 6% 12% 12% 7% 10% 8% 6% 5% 19%	2530
	21st to end	Day	8% 17% 9% 14% 6% 3 5% 5% 5% 6% 22%	3043
February	1st to 10th	Day	8% 11% 6% 9% 7% 4 6% 6% 6% 7% 31%	1710
	11th to 20th	Day	7% 11% 5% 8% 8% 3 6% 5% 5% 7% 34%	1664
	21st to end	Day	10% 11% 6% 9% 7% 3 5% 5% 5% 7% 33%	1498
March	1st to 10th	Day	10% 10% 5% 6% 6% 4 4 4 5% 7% 39%	3275
	11th to 20th	Day	9% 8% 3 7% 5% 4 5% 5% 5% 9% 40%	3480
	21st to end	Day	19% 12% 4 9% 8% 3 5% 4 5% 6% 24%	3923
April	1st to 10th	Day	17% 11% 4 7% 5% 4 4 4 6% 7% 32%	2269
	11th to 20th	Day	20% 12% 5% 7% 4 3 5% 4 4 6% 31%	2134
	21st to end	Day	20% 11% 3 8% 6% 4 5% 4 5% 5% 30%	2315
May	1st to 10th	Day	16% 8% 3 7% 6% 3 5% 5% 5% 6% 34%	2492
	11th to 20th	Day	16% 8% 3 5% 6% 4 5% 5% 5% 6% 35%	2479
	21st to end	Day	14% 7% 3 7% 7% 4 5% 5% 5% 7% 37%	2725
June	1st to 10th	Day	12% 5% 2 5% 5% 2 5% 5% 6% 8% 44%	2520
	11th to 20th	Day	12% 6% 2 6% 5% 3 5% 5% 6% 10% 37%	2520
	21st to end	Day	10% 5% 2 5% 5% 3 6% 6% 7% 10% 40%	2520
July	1st to 10th	Day	6% 4 2 4 4 2 6% 6% 6% 10% 50%	2520
	11th to 20th	Day	9% 4 2 5% 5% 3 5% 5% 6% 8% 50%	2520
	21st to end	Day	7% 4 2 4 4 3 5% 7% 6% 10% 48%	2743
August	1st to 10th	Day	10% 5% 2 5% 6% 4 5% 6% 7% 9% 41%	2374
	11th to 20th	Day	12% 5% 2 5% 5% 3 4 5% 7% 7% 43%	2301
	21st to end	Day	11% 5% 2 5% 4 3 4 3 5% 7% 50%	2440
September	1st to 10th	Day	11% 5% 2 7% 5% 4 4 4 6% 8% 44%	2160
	11th to 20th	Day	13% 5% 2 5% 4 3 5% 5% 6% 8% 44%	2160
	21st to end	Day	16% 7% 3 5% 4 3 4 4 7% 7% 40%	1886
October	1st to 10th	Day	16% 8% 3 4 4 3 5% 5% 5% 7% 40%	1800
	11th to 20th	Day	16% 13% 3 6% 5% 3 4 5% 5% 5% 34%	1800
	21st to end	Day	17% 11% 4 7% 6% 2 3 4 4 6% 35%	1908
November	1st to 10th	Day	11% 14% 5% 8% 6% 3 5% 4 5% 6% 34%	1587
	11th to 20th	Day	13% 11% 8% 10% 9% 3 6% 4 5% 6% 25%	1520
	21st to end	Day	14% 10% 5% 7% 6% 3 5% 5% 6% 8% 33%	1520
December	1st to 10th	Day	11% 13% 6% 11% 11% 4 5% 6% 6% 5% 23%	1520
	11th to 20th	Day	12% 12% 8% 11% 9% 4 5% 5% 5% 5% 25%	1918
	21st to end	Day	22% 16% 6% 13% 8% 4 4 3 3 4 17%	2783
January	1st to 10th	Night	12% 12% 6% 13% 9% 3 5% 4 5% 5% 27%	4428
	11th to 20th	Night	6% 10% 6% 11% 10% 6% 8% 10% 7% 6% 21%	4440
	21st to end	Night	10% 17% 10% 13% 6% 4 4 4 4 5% 22%	4619
February	1st to 10th	Night	6% 10% 5% 10% 8% 4 6% 5% 5% 7% 34%	2470
	11th to 20th	Night	6% 9% 4 9% 6% 4 6% 5% 5% 7% 37%	2403
	21st to end	Night	11% 12% 5% 7% 6% 4 6% 5% 5% 6% 34%	1955
March	1st to 10th	Night	8% 7% 3 6% 6% 3 4 5% 5% 8% 45%	3606
	11th to 20th	Night	8% 7% 3 9% 7% 4 6% 4 6% 6% 39%	3480
	21st to end	Night	24% 10% 4 10% 7% 2 3 2 3 4 29%	3707
April	1st to 10th	Night	18% 11% 3 6% 6% 3 5% 4 4 6% 34%	1900
	11th to 20th	Night	22% 9% 4 6% 5% 3 4 4 3 6% 34%	1775
	21st to end	Night	18% 10% 3 5% 7% 2 4 4 5% 7% 35%	1642
May	1st to 10th	Night	16% 9% 3 6% 6% 4 4 4 5% 6% 37%	1468
	11th to 20th	Night	16% 6% 2 5% 5% 3 4 4 6% 8% 42%	1416
	21st to end	Night	10% 6% 3 6% 5% 3 5% 5% 7% 10% 40%	1551
June	1st to 10th	Night	10% 5% 2 5% 4 3 4 4 6% 9% 46%	1440
	11th to 20th	Night	9% 5% 3 6% 5% 4 5% 4 5% 7% 48%	1440
	21st to end	Night	7% 4 2 4 5% 3 6% 5% 7% 9% 48%	1440
July	1st to 10th	Night	6% 3 1 3 4 2 4 5% 6% 10% 56%	1440
	11th to 20th	Night	6% 5% 1 4 4 3 4 5% 6% 10% 52%	1440
	21st to end	Night	4 3 1 3 3 3 4 5% 6% 9% 59%	1575
August	1st to 10th	Night	6% 4 3 6% 5% 3 4 5% 6% 9% 50%	1562
	11th to 20th	Night	13% 5% 2 3 4 2 3 5% 6% 7% 50%	1600
	21st to end	Night	9% 5% 2 4 5% 3 4 4 4 6% 53%	1916
September	1st to 10th	Night	9% 4 2 5% 5% 3 4 4 5% 8% 52%	1800
	11th to 20th	Night	9% 5% 2 4 4 3 4 5% 5% 7% 52%	1800
	21st to end	Night	15% 5% 2 5% 5% 3 4 5% 4 7% 46%	2050
October	1st to 10th	Night	14% 7% 2 5% 4 3 3 4 5% 6% 46%	2160
	11th to 20th	Night	16% 10% 3 6% 4 3 4 4 4 6% 39%	2160
	21st to end	Night	17% 11% 4 6% 6% 3 4 4 4 7% 35%	2448
November	1st to 10th	Night	14% 9% 4 6% 5% 3 4 4 6% 6% 39%	2489
	11th to 20th	Night	13% 11% 5% 10% 7% 4 4 4 4 5% 33%	2660
	21st to end	Night	13% 9% 4 8% 7% 3 4 4 5% 6% 36%	2660
December	1st to 10th	Night	9% 13% 6% 12% 8% 4 6% 5% 4 7% 27%	2660
	11th to 20th	Night	11% 15% 5% 11% 9% 4 5% 6% 5% 5% 24%	3279
	21st to end	Night	22% 17% 6% 9% 6% 3 4 4 4 4 20%	4884

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	64% 6% 9% 16% 4	2528
	11th to 20th	Day	64% 7% 10% 14% 5%	2530
	21st to end	Day	63% 6% 13% 14% 4	3043
February	1st to 10th	Day	51% 6% 13% 21% 9% 1	1710
	11th to 20th	Day	51% 5% 12% 24% 8% 1	1673
	21st to end	Day	51% 5% 12% 21% 10% 1	1498
March	1st to 10th	Day	44% 6% 16% 22% 12% 1	3275
	11th to 20th	Day	42% 6% 13% 29% 10% 1	3480
	21st to end	Day	61% 6% 8% 19% 5%	3923
April	1st to 10th	Day	51% 6% 10% 19% 13% 1	2269
	11th to 20th	Day	55% 5% 10% 17% 12% 1	2134
	21st to end	Day	56% 6% 11% 18% 9%	2315
May	1st to 10th	Day	50% 6% 13% 21% 9% 1	2492
	11th to 20th	Day	48% 7% 14% 20% 11% 1	2483
	21st to end	Day	45% 8% 9% 25% 11% 1	2725
June	1st to 10th	Day	36% 8% 14% 30% 11% 1	2520
	11th to 20th	Day	40% 9% 15% 23% 13% 1	2520
	21st to end	Day	36% 9% 18% 27% 8% 2	2520
July	1st to 10th	Day	28% 9% 17% 32% 14% 1	2451
	11th to 20th	Day	31% 8% 15% 27% 17% 2	2445
	21st to end	Day	30% 8% 18% 29% 15% 1	2591
August	1st to 10th	Day	37% 9% 17% 27% 9% 2	2359
	11th to 20th	Day	37% 8% 16% 29% 10%	2301
	21st to end	Day	33% 7% 13% 30% 16% 1	2440
September	1st to 10th	Day	37% 7% 13% 31% 11%	2160
	11th to 20th	Day	37% 8% 16% 30% 8%	2160
	21st to end	Day	41% 7% 15% 30% 7%	1886
October	1st to 10th	Day	41% 7% 14% 28% 10% 1	1800
	11th to 20th	Day	50% 7% 12% 20% 10% 1	1800
	21st to end	Day	52% 5% 12% 21% 9%	1908
November	1st to 10th	Day	50% 6% 12% 18% 12% 1	1587
	11th to 20th	Day	59% 7% 12% 14% 7% 1	1520
	21st to end	Day	50% 7% 15% 21% 6% 2	1520
December	1st to 10th	Day	61% 7% 14% 13% 4	1520
	11th to 20th	Day	60% 7% 14% 14% 5% 1	1915
	21st to end	Day	71% 5% 8% 9% 7%	2783
January	1st to 10th	Night	59% 6% 11% 18% 6% 1	4428
	11th to 20th	Night	60% 8% 13% 14% 6%	4440
	21st to end	Night	64% 6% 9% 17% 4 1	4619
February	1st to 10th	Night	49% 6% 11% 23% 10% 2	2470
	11th to 20th	Night	46% 6% 14% 25% 9% 1	2404
	21st to end	Night	50% 6% 12% 20% 10% 1	1955
March	1st to 10th	Night	38% 6% 14% 25% 17% 1	3606
	11th to 20th	Night	44% 5% 11% 26% 14% 1	3480
	21st to end	Night	61% 4 8% 18% 9%	3707
April	1st to 10th	Night	50% 6% 7% 20% 16% 1	1900
	11th to 20th	Night	53% 5% 8% 19% 13% 2	1775
	21st to end	Night	48% 6% 11% 20% 13% 1	1642
May	1st to 10th	Night	48% 6% 14% 18% 14% 1	1468
	11th to 20th	Night	40% 8% 13% 24% 13% 2	1417
	21st to end	Night	38% 9% 14% 22% 16% 2	1552
June	1st to 10th	Night	32% 9% 15% 29% 14% 2	1440
	11th to 20th	Night	36% 7% 14% 23% 18% 2	1440
	21st to end	Night	30% 8% 17% 30% 13% 3	1440
July	1st to 10th	Night	22% 7% 18% 34% 18% 1	1400
	11th to 20th	Night	27% 8% 14% 30% 17% 4	1392
	21st to end	Night	21% 7% 20% 31% 19% 4	1487
August	1st to 10th	Night	31% 7% 13% 31% 14% 4	1553
	11th to 20th	Night	32% 8% 16% 28% 15% 2	1600
	21st to end	Night	32% 8% 13% 28% 17% 3	1916
September	1st to 10th	Night	31% 6% 14% 33% 15% 1	1800
	11th to 20th	Night	30% 6% 17% 32% 14%	1800
	21st to end	Night	37% 6% 13% 32% 11%	2050
October	1st to 10th	Night	37% 6% 12% 30% 12% 2	2160
	11th to 20th	Night	46% 7% 13% 22% 12% 1	2160
	21st to end	Night	49% 6% 13% 21% 10% 1	2448
November	1st to 10th	Night	45% 6% 12% 24% 13% 1	2489
	11th to 20th	Night	54% 6% 13% 16% 11% 1	2660
	21st to end	Night	49% 5% 16% 22% 6% 1	2660
December	1st to 10th	Night	57% 6% 15% 17% 5%	2660
	11th to 20th	Night	60% 6% 12% 17% 5% 1	3281
	21st to end	Night	66% 5% 10% 14% 4	4884

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	14% 12% 36% 28% 7% 3	270
	11th to 20th	Day	15% 11% 40% 27% 6% 1	270
	21st to end	Day	14% 8% 44% 23% 10% 1	297
February	1st to 10th	Day	16% 14% 46% 18% 6% 1	270
	11th to 20th	Day	14% 19% 41% 20% 5% 1	270
	21st to end	Day	16% 15% 46% 23% 1	225
March	1st to 10th	Day	16% 15% 41% 19% 9% 1	270
	11th to 20th	Day	19% 11% 38% 23% 7% 1	270
	21st to end	Day	22% 15% 31% 20% 9% 3	355
April	1st to 10th	Day	22% 16% 36% 21% 5% 1	457
	11th to 20th	Day	28% 11% 25% 27% 8% 1	412
	21st to end	Day	25% 13% 31% 21% 8% 2	575
May	1st to 10th	Day	20% 14% 30% 27% 8% 1	603
	11th to 20th	Day	20% 11% 28% 25% 11% 4	625
	21st to end	Day	17% 10% 28% 25% 16% 4	679
June	1st to 10th	Day	11% 7% 28% 33% 19% 3	630
	11th to 20th	Day	11% 9% 37% 30% 11% 2	630
	21st to end	Day	11% 7% 32% 27% 17% 6%	630
July	1st to 10th	Day	7% 5% 25% 29% 25% 10%	621
	11th to 20th	Day	9% 6% 28% 30% 19% 8%	618
	21st to end	Day	7% 4 26% 36% 19% 8%	684
August	1st to 10th	Day	10% 4 24% 33% 21% 7%	626
	11th to 20th	Day	13% 4 21% 31% 24% 7%	615
	21st to end	Day	12% 7% 25% 32% 20% 5%	559
September	1st to 10th	Day	14% 6% 30% 30% 16% 4	450
	11th to 20th	Day	14% 6% 28% 32% 18% 3	450
	21st to end	Day	21% 11% 29% 25% 11% 3	293
October	1st to 10th	Day	17% 15% 27% 21% 16% 4	270
	11th to 20th	Day	19% 21% 29% 24% 6%	270
	21st to end	Day	23% 16% 39% 14% 6% 2	297
November	1st to 10th	Day	19% 16% 34% 22% 7% 1	270
	11th to 20th	Day	20% 17% 36% 22% 4	270
	21st to end	Day	23% 13% 40% 19% 4	270
December	1st to 10th	Day	16% 12% 43% 20% 9%	270
	11th to 20th	Day	18% 19% 37% 21% 4	270
	21st to end	Day	27% 14% 38% 19% 1	297
January	1st to 10th	Night	13% 10% 39% 29% 8%	950
	11th to 20th	Night	16% 10% 39% 27% 7% 1	950
	21st to end	Night	17% 10% 36% 29% 7% 1	1045
February	1st to 10th	Night	12% 11% 42% 28% 7% 1	950
	11th to 20th	Night	10% 13% 43% 27% 6% 1	929
	21st to end	Night	17% 11% 36% 27% 8%	699
March	1st to 10th	Night	15% 13% 38% 26% 7% 1	685
	11th to 20th	Night	15% 11% 39% 28% 6%	570
	21st to end	Night	21% 11% 31% 25% 10% 2	627
April	1st to 10th	Night	22% 11% 36% 25% 6%	570
	11th to 20th	Night	27% 8% 31% 27% 7% 1	533
	21st to end	Night	22% 10% 29% 29% 8% 1	540
May	1st to 10th	Night	20% 10% 35% 29% 5% 1	540
	11th to 20th	Night	17% 9% 31% 31% 10% 2	531
	21st to end	Night	11% 7% 30% 38% 13% 1	584
June	1st to 10th	Night	11% 5% 30% 40% 13% 1	540
	11th to 20th	Night	10% 5% 34% 41% 10% 1	540
	21st to end	Night	8% 5% 25% 44% 17% 2	540
July	1st to 10th	Night	6% 2 23% 40% 27% 2	525
	11th to 20th	Night	7% 4 26% 42% 19% 1	522
	21st to end	Night	5% 2 23% 45% 22% 3	591
August	1st to 10th	Night	8% 2 15% 53% 20% 1	537
	11th to 20th	Night	14% 3 18% 37% 26% 3	534
	21st to end	Night	11% 3 25% 35% 23% 3	594
September	1st to 10th	Night	11% 5% 23% 40% 18% 3	540
	11th to 20th	Night	11% 5% 30% 34% 17% 2	540
	21st to end	Night	16% 10% 32% 28% 14% 1	638
October	1st to 10th	Night	17% 8% 32% 29% 13% 1	720
	11th to 20th	Night	21% 13% 31% 28% 7%	720
	21st to end	Night	23% 12% 29% 28% 8%	792
November	1st to 10th	Night	20% 10% 34% 29% 7% 1	823
	11th to 20th	Night	18% 13% 36% 26% 7%	950
	21st to end	Night	17% 16% 37% 24% 6%	950
December	1st to 10th	Night	14% 11% 37% 29% 7% 1	950
	11th to 20th	Night	19% 12% 38% 23% 7% 1	950
	21st to end	Night	23% 12% 37% 22% 6%	1045

Page generated at 2024-04-07 08:28:13. Version ac07

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