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 2024-10-20.

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	16% 14% 3 6% 3 3 3 2 4 4 41%	101424
	Night	18% 17% 3 6% 3 3 3 3 4 4 36%	97429
Transparency	Day	48% 2 8% 19% 15% 8%	101167
	Night	53% 2 8% 17% 13% 6%	97275
Seeing	Day	27% 13% 26% 21% 9% 3	14612
	Night	31% 8% 16% 28% 16% 2	23575

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% 37% 4 7% 4 3 3 2 2 3 12%	2539
	11th to 20th	Day	32% 20% 4 6% 4 3 3 2 3 3 20%	2540
	21st to end	Day	32% 22% 4 7% 3 3 3 2 3 4 18%	3050
February	1st to 10th	Day	23% 23% 5% 7% 5% 3 3 3 3 5% 19%	1710
	11th to 20th	Day	22% 24% 4 7% 4 3 4 3 5% 4 21%	1665
	21st to end	Day	21% 30% 4 6% 4 3 3 3 3 4 20%	1526
March	1st to 10th	Day	15% 28% 7% 7% 4 3 3 2 5% 5% 21%	3249
	11th to 20th	Day	15% 23% 3 5% 3 3 3 2 3 3 38%	3490
	21st to end	Day	19% 31% 5% 9% 6% 4 3 2 3 3 14%	3940
April	1st to 10th	Day	23% 29% 4 8% 4 4 3 3 3 3 15%	2280
	11th to 20th	Day	18% 24% 4 8% 4 3 3 3 3 4 25%	2249
	21st to end	Day	20% 21% 2 7% 4 3 4 3 5% 5% 25%	2408
May	1st to 10th	Day	20% 19% 3 7% 4 3 3 2 4 3 32%	4375
	11th to 20th	Day	12% 9% 2 5% 4 3 3 3 4 5% 50%	4377
	21st to end	Day	20% 17% 3 7% 4 4 4 3 5% 6% 26%	4813
June	1st to 10th	Day	26% 10% 2 6% 4 4 3 3 4 5% 32%	2660
	11th to 20th	Day	24% 9% 2 6% 5% 4 4 3 5% 5% 32%	2660
	21st to end	Day	9% 5% 2 5% 3 3 2 3 4 7% 57%	2660
July	1st to 10th	Day	3 2 1 2 1 1 2 1 3 3 80%	4420
	11th to 20th	Day	4 2 1 2 2 1 2 2 3 3 78%	4420
	21st to end	Day	4 2 1 2 1 1 2 2 3 4 78%	4790
August	1st to 10th	Day	3 3 1 3 2 2 2 2 4 5% 73%	4136
	11th to 20th	Day	3 4 2 4 2 3 3 3 5% 6% 63%	4026
	21st to end	Day	7% 4 1 4 3 3 3 3 4 5% 62%	4242
September	1st to 10th	Day	7% 3 1 3 2 2 2 2 3 6% 67%	2280
	11th to 20th	Day	12% 6% 2 6% 3 3 4 3 5% 5% 50%	2280
	21st to end	Day	16% 6% 2 6% 4 4 3 3 3 5% 50%	2013
October	1st to 10th	Day	19% 9% 2 5% 3 2 3 3 3 4 47%	1900
	11th to 20th	Day	23% 8% 2 7% 4 3 3 3 4 6% 37%	1891
	21st to end	Day	26% 11% 3 7% 4 3 3 2 3 4 33%	1926
November	1st to 10th	Day	31% 18% 3 6% 4 4 4 3 3 5% 20%	1627
	11th to 20th	Day	30% 18% 3 5% 4 3 4 3 4 4 21%	1520
	21st to end	Day	23% 19% 3 6% 4 4 3 3 4 4 27%	1520
December	1st to 10th	Day	24% 18% 3 6% 4 3 3 3 4 4 29%	1520
	11th to 20th	Day	27% 20% 4 7% 5% 2 3 3 5% 6% 19%	1928
	21st to end	Day	26% 22% 4 9% 5% 3 3 2 3 4 19%	2794
January	1st to 10th	Night	26% 30% 5% 6% 4 3 3 3 3 3 12%	4406
	11th to 20th	Night	31% 23% 4 5% 3 3 3 2 3 3 19%	4420
	21st to end	Night	31% 22% 4 7% 4 3 3 2 3 4 17%	4610
February	1st to 10th	Night	20% 24% 5% 8% 6% 4 4 3 3 5% 18%	2470
	11th to 20th	Night	21% 26% 4 6% 4 3 3 3 4 4 23%	2402
	21st to end	Night	21% 31% 4 5% 3 3 3 2 4 5% 20%	1927
March	1st to 10th	Night	15% 28% 6% 7% 4 3 4 3 5% 6% 20%	3622
	11th to 20th	Night	13% 22% 3 5% 4 2 3 2 2 4 40%	3490
	21st to end	Night	19% 34% 5% 9% 4 3 3 3 3 3 13%	3712
April	1st to 10th	Night	23% 28% 4 6% 4 3 3 2 4 4 20%	1900
	11th to 20th	Night	19% 25% 5% 6% 3 3 3 3 4 5% 25%	1879
	21st to end	Night	21% 22% 3 6% 5% 4 4 3 4 4 25%	1770
May	1st to 10th	Night	22% 23% 4 6% 3 3 2 2 3 3 31%	2586
	11th to 20th	Night	13% 14% 2 5% 3 3 2 3 4 5% 45%	2516
	21st to end	Night	19% 19% 2 5% 4 3 3 3 5% 6% 31%	2762
June	1st to 10th	Night	24% 11% 2 7% 5% 3 3 3 4 4 34%	1520
	11th to 20th	Night	18% 14% 3 6% 5% 4 4 3 5% 5% 35%	1520
	21st to end	Night	10% 5% 2 4 4 4 3 2 4 4 58%	1520
July	1st to 10th	Night	4 3 1 2 1 1 2 2 2 3 79%	2540
	11th to 20th	Night	3 3 1 3 2 2 2 2 3 3 78%	2540
	21st to end	Night	5% 1 2 2 2 1 1 3 4 80%	2761
August	1st to 10th	Night	2 3 1 3 2 2 2 2 3 6% 74%	2798
	11th to 20th	Night	4 5% 2 5% 3 4 4 3 5% 6% 59%	2812
	21st to end	Night	8% 6% 1 4 2 2 3 2 3 4 65%	3434
September	1st to 10th	Night	7% 3 1 3 2 3 3 2 3 5% 67%	1900
	11th to 20th	Night	12% 6% 2 5% 4 4 3 3 4 5% 51%	1900
	21st to end	Night	15% 7% 2 5% 3 3 4 2 4 6% 49%	2164
October	1st to 10th	Night	18% 9% 3 5% 2 2 3 3 3 4 48%	2280
	11th to 20th	Night	20% 10% 2 5% 3 3 3 3 4 6% 40%	2273
	21st to end	Night	25% 12% 3 6% 4 3 3 2 3 4 36%	2430
November	1st to 10th	Night	30% 18% 4 6% 5% 3 3 3 4 4 21%	2447
	11th to 20th	Night	31% 18% 2 6% 4 3 4 3 4 4 21%	2660
	21st to end	Night	22% 18% 3 6% 3 3 4 3 4 5% 29%	2660
December	1st to 10th	Night	24% 19% 3 6% 3 3 4 3 3 5% 27%	2660
	11th to 20th	Night	23% 23% 3 6% 4 3 4 3 5% 6% 20%	3276
	21st to end	Night	23% 22% 4 8% 4 3 4 3 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	67% 3 9% 13% 7% 3	1674
	21st to end	Day	70% 2 8% 11% 6% 2	1526
March	1st to 10th	Day	67% 2 4 18% 8% 1	3249
	11th to 20th	Day	52% 1 6% 26% 14%	3490
	21st to end	Day	78% 1 6% 10% 5%	3940
April	1st to 10th	Day	75% 2 8% 9% 6%	2280
	11th to 20th	Day	66% 2 9% 12% 9% 3	2252
	21st to end	Day	62% 3 11% 16% 7% 1	2408
May	1st to 10th	Day	59% 1 7% 24% 9%	4375
	11th to 20th	Day	38% 2 12% 33% 15%	4380
	21st to end	Day	61% 2 17% 17% 2	4814
June	1st to 10th	Day	55% 3 12% 21% 9% 1	2660
	11th to 20th	Day	54% 2 12% 21% 8% 2	2660
	21st to end	Day	29% 2 14% 32% 17% 6%	2660
July	1st to 10th	Day	12% 2 6% 16% 25% 40%	4351
	11th to 20th	Day	12% 1 4 13% 24% 45%	4345
	21st to end	Day	12% 2 6% 22% 38% 21%	4639
August	1st to 10th	Day	15% 2 6% 23% 32% 22%	4120
	11th to 20th	Day	19% 5% 9% 36% 25% 6%	4065
	21st to end	Day	24% 3 9% 25% 23% 15%	4241
September	1st to 10th	Day	20% 1 5% 29% 26% 18%	2280
	11th to 20th	Day	36% 3 8% 23% 21% 10%	2280
	21st to end	Day	39% 2 9% 22% 19% 9%	2013
October	1st to 10th	Day	43% 2 6% 17% 24% 7%	1900
	11th to 20th	Day	49% 2 9% 16% 19% 5%	1891
	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	2404
	21st to end	Night	71% 1 6% 12% 8% 2	1927
March	1st to 10th	Night	67% 1 6% 19% 5% 1	3622
	11th to 20th	Night	50% 2 8% 27% 13% 1	3490
	21st to end	Night	79% 2 7% 11% 2	3712
April	1st to 10th	Night	71% 2 10% 11% 6%	1900
	11th to 20th	Night	63% 2 10% 15% 7% 3	1879
	21st to end	Night	64% 4 9% 15% 7% 2	1770
May	1st to 10th	Night	61% 1 7% 19% 12%	2586
	11th to 20th	Night	44% 2 8% 35% 11% 1	2516
	21st to end	Night	56% 3 22% 15% 3	2762
June	1st to 10th	Night	55% 4 13% 21% 6% 1	1520
	11th to 20th	Night	51% 4 13% 23% 7% 2	1520
	21st to end	Night	30% 3 15% 29% 17% 6%	1520
July	1st to 10th	Night	14% 2 7% 15% 28% 36%	2500
	11th to 20th	Night	13% 2 6% 15% 24% 42%	2492
	21st to end	Night	11% 2 7% 24% 38% 19%	2674
August	1st to 10th	Night	15% 2 6% 29% 31% 18%	2790
	11th to 20th	Night	21% 7% 15% 30% 21% 6%	2839
	21st to end	Night	23% 4 12% 23% 23% 15%	3434
September	1st to 10th	Night	21% 2 7% 26% 28% 16%	1900
	11th to 20th	Night	35% 2 7% 25% 17% 12%	1900
	21st to end	Night	37% 3 9% 22% 18% 12%	2164
October	1st to 10th	Night	42% 2 7% 18% 23% 7%	2280
	11th to 20th	Night	46% 4 8% 17% 19% 6%	2273
	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% 23% 12% 4 1	365
	21st to end	Day	44% 14% 22% 16% 3 1	361
March	1st to 10th	Day	42% 15% 23% 18% 2	460
	11th to 20th	Day	36% 16% 25% 18% 5% 1	460
	21st to end	Day	48% 15% 22% 13% 2	506
April	1st to 10th	Day	42% 15% 21% 15% 5% 1	460
	11th to 20th	Day	40% 21% 20% 13% 4 2	452
	21st to end	Day	36% 19% 25% 14% 5% 1	460
May	1st to 10th	Day	27% 18% 29% 19% 6% 2	463
	11th to 20th	Day	32% 12% 26% 19% 8% 3	488
	21st to end	Day	29% 13% 22% 23% 9% 4	529
June	1st to 10th	Day	31% 11% 23% 22% 9% 4	490
	11th to 20th	Day	29% 16% 31% 14% 9% 2	490
	21st to end	Day	10% 13% 35% 26% 12% 4	490
July	1st to 10th	Day	7% 11% 39% 29% 10% 4	486
	11th to 20th	Day	6% 11% 38% 25% 15% 4	484
	21st to end	Day	4 7% 40% 29% 15% 6%	531
August	1st to 10th	Day	4 8% 37% 30% 14% 7%	487
	11th to 20th	Day	5% 9% 29% 35% 14% 8%	477
	21st to end	Day	9% 13% 34% 27% 14% 4	539
September	1st to 10th	Day	10% 10% 33% 30% 14% 4	490
	11th to 20th	Day	19% 10% 29% 29% 12% 2	490
	21st to end	Day	20% 15% 27% 26% 11% 2	490
October	1st to 10th	Day	24% 11% 26% 24% 14% 1	490
	11th to 20th	Day	28% 12% 23% 22% 14% 2	487
	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% 21% 23% 7% 1	744
	21st to end	Night	43% 10% 20% 21% 5%	628
March	1st to 10th	Night	40% 12% 15% 23% 9% 1	760
	11th to 20th	Night	34% 9% 19% 28% 9%	760
	21st to end	Night	42% 11% 17% 20% 9% 1	836
April	1st to 10th	Night	41% 12% 16% 20% 11% 1	760
	11th to 20th	Night	34% 13% 18% 21% 11% 3	751
	21st to end	Night	36% 7% 16% 28% 10% 1	630
May	1st to 10th	Night	32% 6% 16% 28% 15% 2	413
	11th to 20th	Night	29% 4 12% 28% 25% 1	374
	21st to end	Night	30% 5% 14% 27% 23% 1	411
June	1st to 10th	Night	29% 5% 14% 26% 23% 3	380
	11th to 20th	Night	25% 7% 14% 34% 18% 1	380
	21st to end	Night	13% 4 13% 42% 27% 1	380
July	1st to 10th	Night	8% 1 8% 46% 33% 2	370
	11th to 20th	Night	5% 3 11% 50% 31%	368
	21st to end	Night	3 3 6% 46% 40% 3	416
August	1st to 10th	Night	4 1 8% 34% 44% 8%	530
	11th to 20th	Night	6% 2 8% 34% 42% 9%	564
	21st to end	Night	8% 4 16% 43% 27% 2	798
September	1st to 10th	Night	9% 4 14% 40% 30% 3	760
	11th to 20th	Night	16% 3 11% 36% 30% 4	760
	21st to end	Night	20% 5% 14% 37% 23% 2	760
October	1st to 10th	Night	23% 5% 17% 33% 19% 3	760
	11th to 20th	Night	28% 5% 13% 31% 20% 2	758
	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 2024-10-17 10:09:43. Version ac07

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