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 2024-02-20.

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	20% 14% 3 5% 4 2 3 3 4 5% 37%	78348
	Night	21% 17% 3 5% 4 2 3 3 4 5% 32%	80864
Transparency	Day	52% 2 8% 18% 14% 5%	78051
	Night	57% 2 8% 16% 13% 5%	80682
Seeing	Day	28% 13% 26% 21% 9% 2	13644
	Night	31% 7% 16% 28% 16% 2	22816

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	24% 36% 5% 6% 4 2 2 2 2 3 12%	2539
	11th to 20th	Day	32% 19% 4 5% 5% 2 3 3 3 3 20%	2540
	21st to end	Day	32% 21% 4 6% 4 2 3 3 3 4 19%	3050
February	1st to 10th	Day	24% 22% 6% 6% 5% 2 4 4 3 5% 19%	1710
	11th to 20th	Day	23% 23% 4 6% 4 3 4 4 4 4 22%	1657
	21st to end	Day	22% 28% 5% 6% 4 2 3 4 3 4 19%	1439
March	1st to 10th	Day	22% 23% 6% 6% 5% 3 4 3 5% 5% 18%	1859
	11th to 20th	Day	23% 24% 4 5% 4 2 3 3 3 5% 22%	1980
	21st to end	Day	24% 29% 6% 6% 6% 2 4 3 3 4 15%	2242
April	1st to 10th	Day	24% 28% 5% 7% 4 3 4 3 4 4 15%	2160
	11th to 20th	Day	21% 23% 5% 7% 5% 3 3 3 3 3 24%	2129
	21st to end	Day	20% 20% 3 6% 5% 3 4 4 4 6% 25%	2281
May	1st to 10th	Day	19% 15% 3 6% 5% 3 4 3 4 4 34%	2488
	11th to 20th	Day	21% 13% 3 7% 5% 3 5% 5% 5% 6% 28%	2477
	21st to end	Day	27% 12% 3 5% 5% 2 4 4 4 7% 26%	2723
June	1st to 10th	Day	27% 10% 3 6% 5% 3 4 3 3 6% 32%	2520
	11th to 20th	Day	26% 8% 3 6% 6% 3 4 3 5% 6% 32%	2520
	21st to end	Day	10% 5% 2 4 3 2 3 3 4 7% 58%	2520
July	1st to 10th	Day	6% 3 2 2 3 2 3 3 4 5% 68%	2520
	11th to 20th	Day	7% 3 1 2 2 2 2 3 3 4 70%	2520
	21st to end	Day	4 2 1 2 2 1 1 2 3 3 79%	2741
August	1st to 10th	Day	4 3 1 2 2 2 3 3 4 7% 70%	2360
	11th to 20th	Day	4 3 1 2 2 2 3 3 4 6% 70%	2298
	21st to end	Day	5% 3 1 3 3 2 3 4 4 6% 65%	2412
September	1st to 10th	Day	7% 4 1 3 2 1 2 2 3 6% 68%	2160
	11th to 20th	Day	13% 6% 2 5% 4 2 4 4 4 6% 51%	2160
	21st to end	Day	17% 6% 2 5% 5% 3 3 4 3 5% 48%	1908
October	1st to 10th	Day	19% 9% 3 4 4 2 2 4 4 4 45%	1800
	11th to 20th	Day	23% 7% 2 6% 5% 2 3 3 4 6% 37%	1800
	21st to end	Day	26% 11% 3 7% 4 2 3 3 3 4 34%	1926
November	1st to 10th	Day	31% 18% 3 6% 4 2 4 4 3 5% 20%	1627
	11th to 20th	Day	31% 16% 3 5% 5% 2 4 4 4 4 22%	1520
	21st to end	Day	24% 17% 4 5% 5% 3 3 4 4 4 27%	1520
December	1st to 10th	Day	24% 18% 3 5% 4 2 3 3 3 4 29%	1520
	11th to 20th	Day	27% 20% 4 6% 6% 2 3 4 5% 6% 19%	1928
	21st to end	Day	26% 21% 4 8% 6% 3 3 2 3 4 19%	2794
January	1st to 10th	Night	27% 29% 5% 5% 5% 3 4 4 3 3 12%	4406
	11th to 20th	Night	32% 22% 4 5% 4 2 3 3 3 3 19%	4420
	21st to end	Night	31% 21% 4 6% 4 2 3 3 3 4 17%	4610
February	1st to 10th	Night	21% 23% 5% 8% 6% 3 4 4 3 5% 18%	2470
	11th to 20th	Night	22% 25% 5% 5% 5% 2 3 3 3 4 23%	2394
	21st to end	Night	22% 30% 4 5% 4 2 3 3 4 5% 19%	1816
March	1st to 10th	Night	23% 23% 5% 5% 5% 2 4 3 5% 4 20%	2098
	11th to 20th	Night	20% 21% 4 6% 5% 2 4 5% 4 6% 23%	1980
	21st to end	Night	22% 28% 5% 7% 5% 2 4 4 4 4 16%	2113
April	1st to 10th	Night	24% 26% 5% 5% 5% 2 3 3 4 4 20%	1800
	11th to 20th	Night	22% 23% 5% 5% 4 2 3 3 4 4 25%	1779
	21st to end	Night	21% 20% 3 5% 5% 3 4 4 4 5% 25%	1677
May	1st to 10th	Night	18% 17% 3 5% 4 2 3 3 4 5% 37%	1472
	11th to 20th	Night	20% 13% 3 6% 5% 3 4 5% 6% 7% 29%	1416
	21st to end	Night	20% 16% 3 6% 5% 3 3 4 5% 6% 29%	1552
June	1st to 10th	Night	24% 11% 2 6% 5% 3 3 4 4 5% 34%	1440
	11th to 20th	Night	19% 13% 3 5% 5% 2 5% 3 5% 5% 34%	1440
	21st to end	Night	10% 4 2 4 4 3 4 3 4 5% 58%	1440
July	1st to 10th	Night	7% 4 2 3 3 1 2 4 3 4 67%	1440
	11th to 20th	Night	4 3 2 3 3 1 3 3 3 5% 71%	1440
	21st to end	Night	2 2 1 2 2 1 1 2 3 4 79%	1576
August	1st to 10th	Night	3 4 1 2 2 2 2 2 3 5% 72%	1575
	11th to 20th	Night	4 2 2 3 3 2 3 2 3 4 72%	1602
	21st to end	Night	4 4 1 3 3 1 3 3 4 5% 68%	1944
September	1st to 10th	Night	7% 3 1 3 3 2 3 3 3 5% 68%	1800
	11th to 20th	Night	12% 6% 2 4 4 3 4 4 4 5% 52%	1800
	21st to end	Night	16% 7% 2 4 3 2 4 3 4 6% 49%	2049
October	1st to 10th	Night	19% 9% 3 4 3 2 2 4 3 4 46%	2160
	11th to 20th	Night	21% 10% 2 4 4 2 3 3 4 6% 40%	2160
	21st to end	Night	25% 12% 3 5% 5% 2 3 3 3 4 37%	2430
November	1st to 10th	Night	30% 17% 4 6% 5% 2 3 3 4 4 21%	2447
	11th to 20th	Night	32% 17% 2 5% 4 2 4 4 4 4 22%	2660
	21st to end	Night	23% 17% 3 5% 4 2 4 4 4 5% 29%	2660
December	1st to 10th	Night	25% 17% 3 6% 3 2 4 4 3 5% 27%	2660
	11th to 20th	Night	23% 23% 4 5% 5% 2 4 4 4 6% 20%	3276
	21st to end	Night	24% 21% 4 7% 5% 3 4 4 3 4 21%	4862

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	82% 1 4 8% 5%	2539
	11th to 20th	Day	71% 1 6% 12% 4 5%	2540
	21st to end	Day	73% 2 6% 10% 6% 2	3050
February	1st to 10th	Day	70% 3 8% 12% 7% 1	1710
	11th to 20th	Day	66% 3 9% 13% 7% 3	1666
	21st to end	Day	70% 3 8% 10% 7% 3	1439
March	1st to 10th	Day	70% 3 7% 13% 6% 1	1859
	11th to 20th	Day	67% 2 7% 16% 7% 1	1980
	21st to end	Day	77% 2 6% 11% 3	2242
April	1st to 10th	Day	76% 2 8% 9% 6%	2160
	11th to 20th	Day	67% 2 8% 11% 8% 3	2132
	21st to end	Day	61% 3 11% 15% 8% 1	2281
May	1st to 10th	Day	54% 2 11% 23% 9%	2488
	11th to 20th	Day	58% 3 11% 20% 7%	2480
	21st to end	Day	59% 3 13% 20% 4	2724
June	1st to 10th	Day	55% 3 12% 21% 8% 1	2520
	11th to 20th	Day	55% 2 13% 22% 7% 2	2520
	21st to end	Day	29% 2 14% 32% 17% 6%	2520
July	1st to 10th	Day	20% 2 11% 26% 28% 13%	2451
	11th to 20th	Day	19% 2 7% 20% 32% 20%	2445
	21st to end	Day	12% 1 3 24% 41% 19%	2589
August	1st to 10th	Day	17% 2 9% 33% 29% 10%	2343
	11th to 20th	Day	18% 1 9% 28% 33% 10%	2298
	21st to end	Day	21% 2 7% 29% 32% 9%	2412
September	1st to 10th	Day	21% 1 5% 29% 26% 18%	2160
	11th to 20th	Day	36% 2 7% 23% 22% 10%	2160
	21st to end	Day	41% 2 8% 21% 19% 10%	1908
October	1st to 10th	Day	45% 2 7% 17% 23% 7%	1800
	11th to 20th	Day	49% 2 9% 15% 19% 5%	1800
	21st to end	Day	57% 2 7% 12% 19% 4	1926
November	1st to 10th	Day	69% 2 6% 12% 10% 1	1627
	11th to 20th	Day	67% 2 8% 10% 9% 3	1520
	21st to end	Day	62% 2 7% 9% 15% 4	1520
December	1st to 10th	Day	60% 3 8% 15% 11% 3	1520
	11th to 20th	Day	69% 2 9% 11% 9% 1	1928
	21st to end	Day	72% 1 5% 16% 4 1	2794
January	1st to 10th	Night	79% 1 6% 8% 4 1	4406
	11th to 20th	Night	72% 1 6% 12% 5% 4	4420
	21st to end	Night	74% 1 7% 9% 7% 2	4610
February	1st to 10th	Night	70% 3 7% 10% 8% 1	2470
	11th to 20th	Night	66% 2 8% 12% 8% 4	2396
	21st to end	Night	71% 1 6% 11% 9% 2	1816
March	1st to 10th	Night	68% 2 8% 15% 5% 2	2098
	11th to 20th	Night	64% 3 9% 17% 6% 1	1980
	21st to end	Night	74% 3 10% 10% 3	2113
April	1st to 10th	Night	71% 3 9% 11% 6%	1800
	11th to 20th	Night	64% 2 11% 14% 6% 3	1779
	21st to end	Night	63% 4 9% 14% 7% 2	1677
May	1st to 10th	Night	53% 1 12% 22% 12%	1472
	11th to 20th	Night	55% 3 12% 22% 6% 2	1416
	21st to end	Night	57% 5% 13% 19% 6%	1552
June	1st to 10th	Night	55% 4 13% 21% 6% 1	1440
	11th to 20th	Night	52% 3 13% 24% 6% 2	1440
	21st to end	Night	31% 3 15% 28% 17% 6%	1440
July	1st to 10th	Night	24% 2 11% 22% 27% 15%	1400
	11th to 20th	Night	18% 2 9% 20% 29% 23%	1392
	21st to end	Night	11% 2 3 23% 40% 22%	1488
August	1st to 10th	Night	17% 1 9% 32% 30% 10%	1567
	11th to 20th	Night	18% 1 8% 28% 34% 10%	1602
	21st to end	Night	21% 2 8% 28% 32% 9%	1944
September	1st to 10th	Night	21% 1 7% 26% 28% 16%	1800
	11th to 20th	Night	35% 2 6% 25% 18% 13%	1800
	21st to end	Night	38% 2 9% 21% 18% 12%	2049
October	1st to 10th	Night	44% 2 7% 19% 22% 7%	2160
	11th to 20th	Night	46% 4 8% 16% 20% 7%	2160
	21st to end	Night	54% 3 6% 12% 20% 5%	2430
November	1st to 10th	Night	68% 2 6% 10% 12% 3	2447
	11th to 20th	Night	67% 2 8% 11% 9% 3	2660
	21st to end	Night	60% 2 5% 11% 16% 6%	2660
December	1st to 10th	Night	61% 3 8% 15% 11% 3	2660
	11th to 20th	Night	68% 1 10% 10% 10% 1	3276
	21st to end	Night	69% 1 8% 14% 6% 2	4862

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	48% 20% 16% 9% 7%	180
	11th to 20th	Day	43% 13% 18% 17% 7% 2	180
	21st to end	Day	41% 14% 17% 18% 8% 2	350
February	1st to 10th	Day	42% 17% 21% 14% 7% 1	370
	11th to 20th	Day	43% 18% 22% 12% 4 1	363
	21st to end	Day	44% 15% 23% 16% 3 1	328
March	1st to 10th	Day	44% 15% 22% 17% 2	420
	11th to 20th	Day	37% 16% 24% 19% 4	420
	21st to end	Day	49% 14% 21% 14% 2	462
April	1st to 10th	Day	43% 14% 22% 15% 6% 1	420
	11th to 20th	Day	42% 20% 17% 13% 5% 2	412
	21st to end	Day	35% 19% 26% 14% 5% 1	420
May	1st to 10th	Day	26% 17% 29% 20% 7% 1	423
	11th to 20th	Day	34% 12% 25% 18% 7% 3	448
	21st to end	Day	30% 13% 21% 24% 9% 4	485
June	1st to 10th	Day	31% 11% 24% 22% 8% 4	450
	11th to 20th	Day	30% 15% 31% 14% 9% 2	450
	21st to end	Day	10% 12% 35% 27% 12% 4	450
July	1st to 10th	Day	7% 10% 40% 29% 10% 4	446
	11th to 20th	Day	6% 11% 39% 26% 15% 4	444
	21st to end	Day	4 7% 40% 29% 15% 6%	487
August	1st to 10th	Day	4 8% 37% 30% 14% 7%	447
	11th to 20th	Day	4 8% 29% 36% 14% 8%	437
	21st to end	Day	8% 12% 35% 27% 14% 3	495
September	1st to 10th	Day	11% 10% 32% 30% 14% 3	450
	11th to 20th	Day	19% 9% 28% 30% 12% 2	450
	21st to end	Day	21% 15% 26% 26% 10% 2	450
October	1st to 10th	Day	25% 11% 26% 24% 12% 1	450
	11th to 20th	Day	28% 10% 23% 21% 15% 3	450
	21st to end	Day	35% 13% 20% 19% 10% 2	441
November	1st to 10th	Day	38% 16% 15% 24% 6% 1	248
	11th to 20th	Day	42% 11% 19% 11% 17% 1	180
	21st to end	Day	41% 13% 19% 15% 12%	180
December	1st to 10th	Day	39% 15% 17% 16% 11% 1	180
	11th to 20th	Day	50% 14% 19% 13% 2 1	180
	21st to end	Day	42% 17% 17% 15% 8% 1	198
January	1st to 10th	Night	44% 11% 18% 19% 8% 1	760
	11th to 20th	Night	42% 8% 19% 18% 11% 2	760
	21st to end	Night	37% 8% 21% 23% 9% 2	836
February	1st to 10th	Night	34% 11% 21% 25% 8% 1	760
	11th to 20th	Night	38% 11% 20% 23% 7% 1	742
	21st to end	Night	43% 11% 20% 21% 5%	592
March	1st to 10th	Night	40% 12% 15% 23% 9% 1	720
	11th to 20th	Night	35% 9% 18% 28% 9%	720
	21st to end	Night	43% 10% 16% 21% 9% 1	792
April	1st to 10th	Night	41% 11% 15% 19% 11% 1	720
	11th to 20th	Night	36% 11% 17% 22% 12% 3	711
	21st to end	Night	36% 7% 16% 29% 11% 1	597
May	1st to 10th	Night	31% 6% 15% 29% 16% 2	392
	11th to 20th	Night	30% 4 12% 27% 25% 1	354
	21st to end	Night	30% 5% 14% 25% 24% 1	389
June	1st to 10th	Night	29% 5% 14% 25% 24% 3	360
	11th to 20th	Night	26% 8% 13% 34% 19% 1	360
	21st to end	Night	13% 4 13% 41% 28% 1	360
July	1st to 10th	Night	9% 1 8% 45% 34% 3	350
	11th to 20th	Night	5% 3 10% 51% 31%	348
	21st to end	Night	3 2 6% 46% 40% 3	394
August	1st to 10th	Night	5% 1 8% 32% 46% 8%	501
	11th to 20th	Night	6% 2 7% 32% 44% 9%	534
	21st to end	Night	7% 4 15% 43% 28% 2	756
September	1st to 10th	Night	9% 4 14% 40% 30% 3	720
	11th to 20th	Night	16% 3 10% 36% 31% 4	720
	21st to end	Night	20% 5% 13% 36% 24% 2	720
October	1st to 10th	Night	24% 5% 16% 32% 19% 3	720
	11th to 20th	Night	28% 5% 13% 30% 21% 3	720
	21st to end	Night	33% 8% 18% 25% 12% 3	792
November	1st to 10th	Night	41% 8% 16% 27% 8%	740
	11th to 20th	Night	45% 8% 18% 21% 7%	760
	21st to end	Night	36% 10% 19% 27% 8% 1	760
December	1st to 10th	Night	38% 8% 21% 23% 8% 2	760
	11th to 20th	Night	44% 8% 19% 21% 7% 1	760
	21st to end	Night	48% 10% 19% 18% 4 1	836

Page generated at 2024-02-17 03:28:41. Version ac07

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