Detroit Lake State Recreation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Detroit Lake State Recreation Area clear sky chart from 2005-11-06 to 2026-07-31.

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	15% 13% 3 6% 4 3 3 3 4 5% 42%	147594
	Night	17% 17% 3 6% 3 3 3 3 4 5% 37%	142766
Transparency	Day	45% 3 8% 20% 16% 8%	142376
	Night	51% 3 8% 17% 14% 6%	138983
Seeing	Day	27% 14% 27% 21% 9% 2	16820
	Night	30% 8% 17% 28% 15% 2	25769

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	27% 30% 4 7% 4 4 3 2 3 3 11%	4722
	11th to 20th	Day	17% 13% 3 4 3 2 3 2 3 4 46%	4740
	21st to end	Day	22% 13% 2 6% 3 4 4 3 5% 5% 33%	5663
February	1st to 10th	Day	22% 23% 6% 8% 5% 3 3 3 3 5% 18%	1890
	11th to 20th	Day	21% 24% 4 7% 4 4 4 3 4 4 21%	1845
	21st to end	Day	21% 28% 5% 6% 4 3 3 3 3 4 20%	1682
March	1st to 10th	Day	15% 25% 6% 7% 4 3 3 3 6% 7% 23%	4784
	11th to 20th	Day	18% 29% 4 7% 4 3 3 2 2 3 27%	5110
	21st to end	Day	20% 28% 4 9% 6% 5% 4 3 4 5% 13%	5778
April	1st to 10th	Day	21% 28% 4 8% 4 4 4 3 4 4 16%	2520
	11th to 20th	Day	18% 23% 4 8% 4 3 3 3 3 4 26%	2489
	21st to end	Day	19% 20% 3 7% 4 3 4 3 5% 5% 27%	2662
May	1st to 10th	Day	12% 12% 2 6% 4 3 4 3 4 5% 44%	8098
	11th to 20th	Day	14% 15% 3 8% 5% 4 3 2 4 5% 37%	8160
	21st to end	Day	14% 11% 2 6% 4 4 5% 4 5% 7% 39%	8992
June	1st to 10th	Day	24% 10% 2 6% 4 4 3 3 4 5% 35%	2940
	11th to 20th	Day	22% 9% 2 6% 5% 4 4 3 5% 5% 36%	2940
	21st to end	Day	10% 6% 2 5% 3 3 3 3 4 7% 55%	2940
July	1st to 10th	Day	3 2 1 2 1 2 2 1 3 4 80%	6459
	11th to 20th	Day	3 2 1 2 1 1 2 2 2 3 82%	6460
	21st to end	Day	3 2 1 2 2 1 2 2 3 5% 77%	7021
August	1st to 10th	Day	3 3 1 3 2 2 2 2 4 5% 71%	5848
	11th to 20th	Day	5% 4 1 4 2 3 3 3 5% 6% 64%	5796
	21st to end	Day	6% 4 1 4 3 4 4 4 5% 6% 58%	6072
September	1st to 10th	Day	7% 4 1 4 2 2 3 2 3 6% 65%	2400
	11th to 20th	Day	12% 6% 2 6% 3 3 4 3 5% 5% 51%	2400
	21st to end	Day	16% 6% 2 6% 4 4 3 3 3 5% 50%	2119
October	1st to 10th	Day	13% 7% 2 4 3 3 3 2 4 4 56%	3280
	11th to 20th	Day	18% 8% 2 7% 5% 4 4 3 5% 6% 37%	3261
	21st to end	Day	25% 15% 3 7% 5% 5% 5% 3 4 5% 23%	3462
November	1st to 10th	Day	31% 18% 3 6% 4 4 4 3 3 5% 20%	1801
	11th to 20th	Day	29% 18% 3 6% 5% 4 4 3 4 4 20%	1680
	21st to end	Day	22% 19% 3 6% 4 4 3 3 4 5% 27%	1680
December	1st to 10th	Day	20% 15% 2 4 3 2 3 2 4 5% 40%	2700
	11th to 20th	Day	27% 23% 4 9% 5% 4 4 3 4 4 13%	3108
	21st to end	Day	27% 25% 4 10% 5% 3 3 2 3 4 15%	4092
January	1st to 10th	Night	28% 27% 4 6% 4 4 4 3 3 3 13%	8172
	11th to 20th	Night	17% 16% 3 4 2 3 3 2 4 5% 42%	8220
	21st to end	Night	20% 15% 3 8% 4 4 3 2 3 5% 33%	8525
February	1st to 10th	Night	19% 24% 5% 8% 5% 4 4 3 3 5% 19%	2730
	11th to 20th	Night	21% 27% 5% 6% 4 3 3 3 4 4 22%	2662
	21st to end	Night	21% 29% 4 5% 3 3 3 2 4 5% 21%	2123
March	1st to 10th	Night	15% 25% 5% 7% 4 4 4 3 6% 6% 20%	5327
	11th to 20th	Night	17% 28% 5% 6% 4 2 3 2 2 3 28%	5110
	21st to end	Night	24% 30% 5% 8% 4 3 3 2 3 4 13%	5438
April	1st to 10th	Night	22% 27% 4 6% 4 3 3 3 4 4 20%	2100
	11th to 20th	Night	18% 24% 4 6% 3 3 3 3 4 5% 26%	2079
	21st to end	Night	19% 22% 3 6% 5% 4 3 3 4 4 27%	1956
May	1st to 10th	Night	14% 15% 3 6% 3 4 3 2 4 5% 41%	4825
	11th to 20th	Night	13% 25% 3 7% 3 3 2 2 4 5% 33%	4700
	21st to end	Night	15% 14% 2 5% 3 3 3 3 5% 7% 39%	5181
June	1st to 10th	Night	22% 11% 2 7% 5% 3 3 3 4 4 36%	1680
	11th to 20th	Night	16% 13% 2 6% 4 3 4 3 5% 5% 38%	1680
	21st to end	Night	10% 6% 2 4 4 4 3 2 4 4 57%	1680
July	1st to 10th	Night	3 2 1 3 2 2 3 2 3 4 74%	3720
	11th to 20th	Night	2 2 1 2 2 1 2 2 3 3 81%	3720
	21st to end	Night	4 2 1 2 2 2 2 2 3 4 78%	4050
August	1st to 10th	Night	3 3 2 4 3 3 3 3 4 6% 65%	3957
	11th to 20th	Night	7% 5% 2 5% 3 3 3 3 4 6% 59%	4052
	21st to end	Night	7% 5% 2 4 3 2 3 3 4 5% 62%	4923
September	1st to 10th	Night	7% 4 1 3 3 3 3 3 4 5% 65%	2000
	11th to 20th	Night	12% 6% 2 5% 4 4 4 3 4 5% 52%	2000
	21st to end	Night	14% 7% 2 5% 3 3 4 3 4 6% 50%	2278
October	1st to 10th	Night	14% 7% 2 5% 2 2 3 3 4 4 54%	3920
	11th to 20th	Night	17% 11% 2 5% 4 4 4 3 5% 7% 38%	3897
	21st to end	Night	25% 18% 3 7% 4 4 3 3 4 4 26%	4346
November	1st to 10th	Night	30% 18% 3 6% 5% 3 3 3 4 4 20%	2713
	11th to 20th	Night	31% 19% 3 6% 4 3 4 3 4 4 20%	2940
	21st to end	Night	22% 18% 3 6% 4 4 4 3 4 5% 28%	2940
December	1st to 10th	Night	16% 16% 2 4 3 3 3 3 4 5% 40%	4700
	11th to 20th	Night	26% 24% 4 8% 5% 4 4 3 4 5% 14%	5316
	21st to end	Night	29% 24% 4 8% 4 3 3 2 3 3 17%	7106

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	78% 3 4 9% 6%	4723
	11th to 20th	Day	42% 2 5% 16% 19% 16%	4740
	21st to end	Day	53% 3 5% 12% 20% 7%	5663
February	1st to 10th	Day	69% 4 7% 12% 7% 1	1890
	11th to 20th	Day	66% 3 8% 13% 7% 3	1854
	21st to end	Day	68% 3 8% 10% 8% 3	1682
March	1st to 10th	Day	61% 3 8% 17% 10% 1	4784
	11th to 20th	Day	64% 2 5% 18% 10%	5110
	21st to end	Day	74% 4 7% 10% 4	5778
April	1st to 10th	Day	73% 2 9% 10% 6%	2520
	11th to 20th	Day	63% 2 9% 14% 9% 3	2492
	21st to end	Day	59% 3 11% 17% 8% 2	2662
May	1st to 10th	Day	42% 3 9% 29% 16% 2	8098
	11th to 20th	Day	49% 4 12% 25% 10%	8163
	21st to end	Day	44% 5% 19% 24% 7% 1	8994
June	1st to 10th	Day	52% 3 12% 22% 10% 2	2940
	11th to 20th	Day	50% 2 12% 22% 11% 3	2940
	21st to end	Day	30% 3 14% 31% 17% 6%	2940
July	1st to 10th	Day	11% 2 7% 24% 28% 29%	6391
	11th to 20th	Day	10% 1 4 12% 30% 42%	6385
	21st to end	Day	12% 3 8% 33% 31% 14%	6822
August	1st to 10th	Day	15% 2 6% 23% 32% 21%	4252
	11th to 20th	Day	19% 5% 9% 36% 24% 6%	4195
	21st to end	Day	24% 3 9% 25% 23% 15%	4375
September	1st to 10th	Day	22% 2 5% 29% 25% 17%	2400
	11th to 20th	Day	35% 3 8% 24% 20% 10%	2400
	21st to end	Day	38% 2 8% 22% 20% 10%	2119
October	1st to 10th	Day	33% 3 5% 18% 29% 12%	3280
	11th to 20th	Day	46% 5% 11% 20% 15% 3	3261
	21st to end	Day	59% 6% 7% 13% 13% 2	3462
November	1st to 10th	Day	69% 2 6% 13% 9% 1	1801
	11th to 20th	Day	68% 3 8% 10% 8% 2	1680
	21st to end	Day	61% 3 7% 10% 14% 4	1680
December	1st to 10th	Day	48% 3 6% 13% 22% 8%	2700
	11th to 20th	Day	74% 4 7% 8% 6% 1	3108
	21st to end	Day	76% 1 4 14% 3 1	4092
January	1st to 10th	Night	76% 3 5% 10% 5% 1	8172
	11th to 20th	Night	45% 2 5% 15% 17% 15%	8220
	21st to end	Night	56% 2 4 9% 20% 8%	8525
February	1st to 10th	Night	69% 4 8% 10% 8% 2	2730
	11th to 20th	Night	67% 3 8% 12% 7% 4	2664
	21st to end	Night	68% 2 6% 12% 9% 2	2123
March	1st to 10th	Night	62% 3 9% 17% 6% 3	5327
	11th to 20th	Night	62% 2 7% 19% 9% 1	5110
	21st to end	Night	76% 3 9% 11% 2	5438
April	1st to 10th	Night	69% 3 11% 12% 5%	2100
	11th to 20th	Night	62% 2 11% 16% 7% 2	2079
	21st to end	Night	61% 4 10% 15% 8% 2	1956
May	1st to 10th	Night	45% 4 10% 26% 14%	4823
	11th to 20th	Night	56% 4 8% 25% 7% 1	4700
	21st to end	Night	45% 5% 23% 21% 6%	5182
June	1st to 10th	Night	53% 4 12% 23% 7% 1	1680
	11th to 20th	Night	48% 4 12% 25% 9% 3	1680
	21st to end	Night	31% 3 15% 27% 18% 5%	1680
July	1st to 10th	Night	16% 3 8% 22% 26% 24%	3680
	11th to 20th	Night	11% 2 6% 12% 32% 36%	3672
	21st to end	Night	11% 3 12% 34% 28% 13%	3937
August	1st to 10th	Night	15% 2 6% 29% 30% 17%	2878
	11th to 20th	Night	21% 7% 15% 30% 21% 6%	2929
	21st to end	Night	23% 4 11% 23% 23% 15%	3542
September	1st to 10th	Night	22% 2 8% 26% 27% 15%	2000
	11th to 20th	Night	35% 3 8% 25% 18% 12%	2000
	21st to end	Night	36% 3 9% 23% 18% 12%	2278
October	1st to 10th	Night	33% 4 6% 18% 31% 9%	3920
	11th to 20th	Night	44% 5% 13% 21% 13% 4	3897
	21st to end	Night	59% 6% 6% 14% 12% 3	4346
November	1st to 10th	Night	68% 3 6% 10% 11% 2	2713
	11th to 20th	Night	69% 2 8% 10% 8% 3	2940
	21st to end	Night	60% 2 6% 11% 15% 5%	2940
December	1st to 10th	Night	45% 3 7% 15% 24% 6%	4700
	11th to 20th	Night	73% 3 9% 8% 6% 1	5316
	21st to end	Night	73% 2 7% 12% 5% 1	7106

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	49% 19% 15% 11% 6%	220
	11th to 20th	Day	36% 12% 20% 21% 8% 3	220
	21st to end	Day	38% 14% 18% 18% 10% 2	410
February	1st to 10th	Day	41% 16% 22% 14% 7% 1	430
	11th to 20th	Day	41% 19% 25% 11% 4 1	425
	21st to end	Day	43% 15% 23% 15% 3	421
March	1st to 10th	Day	43% 16% 22% 17% 2	540
	11th to 20th	Day	38% 18% 24% 16% 4 1	540
	21st to end	Day	46% 16% 22% 13% 2	594
April	1st to 10th	Day	39% 15% 22% 15% 7% 1	540
	11th to 20th	Day	38% 21% 20% 14% 5% 2	532
	21st to end	Day	33% 19% 28% 15% 5% 1	540
May	1st to 10th	Day	24% 18% 30% 19% 8% 1	543
	11th to 20th	Day	35% 13% 24% 18% 7% 3	568
	21st to end	Day	27% 13% 24% 24% 9% 4	617
June	1st to 10th	Day	30% 12% 24% 21% 9% 4	570
	11th to 20th	Day	26% 15% 33% 15% 9% 2	570
	21st to end	Day	12% 14% 34% 24% 13% 4	570
July	1st to 10th	Day	6% 10% 40% 29% 11% 4	566
	11th to 20th	Day	6% 13% 38% 25% 15% 4	564
	21st to end	Day	5% 7% 39% 28% 15% 6%	616
August	1st to 10th	Day	4 8% 37% 30% 14% 7%	527
	11th to 20th	Day	5% 9% 30% 34% 13% 8%	517
	21st to end	Day	9% 13% 33% 26% 15% 4	583
September	1st to 10th	Day	10% 10% 32% 29% 15% 3	530
	11th to 20th	Day	18% 10% 29% 29% 12% 2	530
	21st to end	Day	19% 14% 27% 26% 12% 2	530
October	1st to 10th	Day	24% 12% 27% 22% 13% 1	530
	11th to 20th	Day	29% 12% 24% 20% 13% 2	530
	21st to end	Day	36% 13% 22% 18% 10% 2	523
November	1st to 10th	Day	39% 16% 15% 23% 6% 1	302
	11th to 20th	Day	43% 12% 19% 10% 15%	220
	21st to end	Day	38% 13% 20% 16% 12%	220
December	1st to 10th	Day	41% 12% 15% 16% 14% 1	220
	11th to 20th	Day	51% 15% 17% 12% 3 1	220
	21st to end	Day	45% 16% 17% 13% 7% 1	242
January	1st to 10th	Night	44% 12% 20% 17% 7% 1	840
	11th to 20th	Night	38% 8% 21% 20% 11% 2	840
	21st to end	Night	35% 9% 22% 24% 8% 2	924
February	1st to 10th	Night	33% 11% 22% 25% 8% 1	840
	11th to 20th	Night	37% 12% 21% 22% 7%	824
	21st to end	Night	43% 11% 22% 21% 4	692
March	1st to 10th	Night	40% 13% 15% 23% 8% 1	840
	11th to 20th	Night	36% 9% 20% 26% 8%	840
	21st to end	Night	42% 11% 17% 20% 8% 1	924
April	1st to 10th	Night	39% 11% 16% 21% 11% 1	840
	11th to 20th	Night	33% 12% 18% 23% 10% 2	831
	21st to end	Night	34% 8% 17% 29% 10% 1	696
May	1st to 10th	Night	29% 7% 16% 29% 16% 2	457
	11th to 20th	Night	32% 5% 12% 27% 23% 1	414
	21st to end	Night	29% 6% 14% 29% 22% 1	455
June	1st to 10th	Night	28% 6% 15% 26% 23% 3	420
	11th to 20th	Night	23% 7% 15% 36% 17% 1	420
	21st to end	Night	14% 5% 13% 41% 27% 1	420
July	1st to 10th	Night	8% 2 10% 46% 33% 2	410
	11th to 20th	Night	5% 3 13% 49% 29%	408
	21st to end	Night	3 3 6% 45% 40% 3	458
August	1st to 10th	Night	4 1 8% 35% 44% 7%	558
	11th to 20th	Night	6% 2 8% 35% 41% 8%	594
	21st to end	Night	7% 4 15% 44% 27% 2	840
September	1st to 10th	Night	9% 5% 14% 41% 29% 2	800
	11th to 20th	Night	16% 3 11% 36% 30% 4	800
	21st to end	Night	19% 5% 14% 37% 23% 2	800
October	1st to 10th	Night	24% 5% 18% 33% 18% 3	800
	11th to 20th	Night	29% 6% 13% 31% 19% 2	800
	21st to end	Night	34% 8% 20% 24% 11% 3	880
November	1st to 10th	Night	42% 8% 16% 27% 7%	820
	11th to 20th	Night	45% 10% 18% 20% 6%	840
	21st to end	Night	35% 10% 19% 27% 8% 1	840
December	1st to 10th	Night	37% 8% 21% 24% 8% 1	840
	11th to 20th	Night	45% 8% 19% 20% 7% 1	840
	21st to end	Night	48% 11% 20% 17% 4 1	924

Page generated at 2026-07-28 00:25:22. Version ac07

Copyright © 2026 Attilla Danko.