Chain O' Lakes State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chain O' Lakes State Park clear sky chart from 2005-11-06 to 2024-12-24.

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	14% 10% 4 8% 5% 5% 4 4 6% 7% 34%	101559
	Night	15% 10% 4 8% 5% 4 4 3 5% 7% 35%	98602
Transparency	Day	47% 6% 12% 21% 13% 1	105173
	Night	47% 6% 11% 21% 13% 2	103128
Seeing	Day	17% 10% 27% 24% 15% 6%	15826
	Night	19% 9% 29% 29% 13% 1	25712

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	16% 16% 11% 13% 5% 4 4 3 4 5% 20%	2527
	11th to 20th	Day	15% 17% 8% 13% 6% 5% 5% 6% 7% 4 11%	2530
	21st to end	Day	27% 22% 9% 12% 4 3 3 2 3 3 13%	2885
February	1st to 10th	Day	15% 15% 6% 11% 7% 6% 4 3 4 6% 22%	1803
	11th to 20th	Day	14% 14% 5% 13% 8% 5% 4 4 5% 6% 23%	1848
	21st to end	Day	16% 16% 6% 11% 5% 3 4 4 5% 5% 25%	1570
March	1st to 10th	Day	19% 16% 5% 9% 5% 4 3 3 5% 6% 25%	3120
	11th to 20th	Day	14% 9% 4 7% 5% 5% 5% 4 6% 8% 33%	3411
	21st to end	Day	20% 12% 5% 10% 6% 4 4 4 4 6% 24%	3904
April	1st to 10th	Day	16% 13% 4 8% 5% 4 4 3 5% 6% 31%	2280
	11th to 20th	Day	17% 9% 3 6% 5% 5% 4 3 5% 6% 36%	2296
	21st to end	Day	18% 9% 3 7% 5% 4 4 3 5% 7% 34%	2470
May	1st to 10th	Day	19% 8% 3 7% 5% 4 5% 4 6% 7% 31%	4082
	11th to 20th	Day	16% 7% 2 6% 5% 5% 5% 4 6% 8% 37%	4081
	21st to end	Day	9% 6% 2 6% 5% 5% 5% 4 7% 9% 42%	4626
June	1st to 10th	Day	10% 6% 2 7% 5% 6% 5% 5% 6% 8% 41%	2660
	11th to 20th	Day	9% 6% 2 6% 4 5% 5% 4 6% 9% 44%	2660
	21st to end	Day	11% 6% 3 6% 5% 5% 6% 5% 7% 9% 39%	2660
July	1st to 10th	Day	13% 6% 2 7% 5% 5% 4 4 6% 9% 37%	4440
	11th to 20th	Day	7% 4 2 5% 3 4 5% 5% 7% 11% 47%	4440
	21st to end	Day	6% 6% 2 8% 6% 5% 6% 4 6% 9% 41%	4698
August	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 4 6% 8% 45%	4104
	11th to 20th	Day	9% 5% 2 6% 4 5% 4 4 6% 8% 46%	4044
	21st to end	Day	7% 5% 2 6% 4 4 4 4 6% 9% 48%	4190
September	1st to 10th	Day	11% 5% 2 6% 5% 4 5% 4 6% 6% 45%	2223
	11th to 20th	Day	9% 4 1 5% 4 4 4 5% 7% 8% 48%	2090
	21st to end	Day	14% 7% 2 6% 4 5% 4 4 5% 9% 41%	2090
October	1st to 10th	Day	13% 7% 2 6% 4 4 4 4 5% 7% 44%	2090
	11th to 20th	Day	16% 7% 2 8% 4 4 5% 4 5% 7% 37%	1904
	21st to end	Day	19% 10% 4 8% 5% 5% 4 4 6% 7% 28%	1881
November	1st to 10th	Day	11% 9% 3 7% 4 4 3 4 5% 7% 44%	1762
	11th to 20th	Day	17% 14% 4 9% 5% 4 4 3 4 6% 30%	1800
	21st to end	Day	21% 14% 5% 9% 5% 3 5% 3 5% 5% 26%	1800
December	1st to 10th	Day	14% 19% 5% 12% 6% 4 4 3 5% 5% 22%	1785
	11th to 20th	Day	14% 15% 7% 12% 7% 4 5% 3 5% 6% 22%	1998
	21st to end	Day	24% 21% 7% 13% 6% 4 4 3 3 4 11%	2807
January	1st to 10th	Night	17% 16% 7% 13% 5% 4 4 3 5% 5% 22%	4428
	11th to 20th	Night	14% 19% 7% 15% 7% 4 6% 5% 6% 4 13%	4440
	21st to end	Night	26% 19% 8% 11% 4 3 3 2 4 5% 15%	4776
February	1st to 10th	Night	18% 14% 5% 10% 6% 5% 4 3 4 5% 25%	2375
	11th to 20th	Night	13% 13% 4 10% 7% 5% 4 3 5% 6% 29%	2218
	21st to end	Night	20% 13% 4 10% 5% 4 4 3 4 5% 29%	1884
March	1st to 10th	Night	17% 13% 5% 7% 4 4 4 3 4 6% 34%	3733
	11th to 20th	Night	10% 7% 3 6% 4 4 5% 4 5% 7% 44%	3547
	21st to end	Night	18% 10% 4 8% 5% 4 4 4 5% 6% 33%	3756
April	1st to 10th	Night	15% 10% 2 5% 5% 4 5% 4 5% 7% 37%	1900
	11th to 20th	Night	18% 8% 3 6% 5% 5% 5% 3 5% 6% 37%	1833
	21st to end	Night	17% 9% 3 6% 5% 4 4 4 5% 7% 36%	1710
May	1st to 10th	Night	16% 9% 3 8% 5% 5% 5% 4 6% 8% 31%	2813
	11th to 20th	Night	19% 7% 2 6% 4 4 4 3 5% 7% 39%	2812
	21st to end	Night	13% 6% 2 6% 4 4 4 4 6% 8% 44%	2930
June	1st to 10th	Night	9% 5% 3 5% 3 4 4 3 6% 9% 48%	1520
	11th to 20th	Night	8% 5% 2 7% 6% 4 5% 4 7% 8% 45%	1520
	21st to end	Night	9% 5% 2 6% 5% 5% 4 4 7% 8% 43%	1520
July	1st to 10th	Night	10% 5% 2 6% 5% 5% 4 4 6% 9% 46%	2530
	11th to 20th	Night	7% 4 1 4 4 3 4 3 5% 9% 55%	2530
	21st to end	Night	7% 6% 2 6% 4 3 5% 4 7% 10% 45%	2862
August	1st to 10th	Night	11% 6% 2 6% 4 4 5% 4 6% 10% 42%	2825
	11th to 20th	Night	8% 6% 2 7% 4 4 4 4 5% 7% 48%	2785
	21st to end	Night	8% 5% 2 5% 4 4 4 4 6% 8% 49%	3463
September	1st to 10th	Night	10% 5% 1 6% 3 4 4 3 4 7% 52%	1936
	11th to 20th	Night	10% 4 2 4 3 3 3 3 5% 7% 56%	2090
	21st to end	Night	13% 7% 3 5% 3 3 4 3 5% 7% 46%	2090
October	1st to 10th	Night	11% 6% 2 5% 4 4 4 3 5% 7% 50%	2090
	11th to 20th	Night	18% 8% 2 7% 5% 3 3 3 5% 5% 40%	2271
	21st to end	Night	21% 8% 2 6% 4 4 3 3 5% 6% 37%	2717
November	1st to 10th	Night	13% 9% 3 6% 4 4 3 3 5% 7% 43%	2536
	11th to 20th	Night	16% 12% 3 8% 5% 4 4 3 7% 7% 32%	2600
	21st to end	Night	18% 14% 5% 9% 5% 4 4 4 5% 6% 26%	2600
December	1st to 10th	Night	16% 16% 6% 9% 6% 5% 4 3 5% 7% 23%	2610
	11th to 20th	Night	18% 15% 7% 11% 5% 4 4 3 5% 5% 23%	3419
	21st to end	Night	26% 18% 7% 11% 5% 4 4 3 4 5% 13%	4933

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	67% 5% 10% 13% 5%	2528
	11th to 20th	Day	70% 5% 10% 10% 5%	2530
	21st to end	Day	79% 3 6% 9% 3	2885
February	1st to 10th	Day	63% 5% 10% 14% 7% 1	1803
	11th to 20th	Day	61% 6% 9% 17% 8% 1	1858
	21st to end	Day	60% 5% 11% 16% 6% 1	1570
March	1st to 10th	Day	61% 5% 9% 19% 7%	3120
	11th to 20th	Day	46% 6% 13% 26% 7% 1	3411
	21st to end	Day	59% 7% 13% 17% 3	3904
April	1st to 10th	Day	53% 7% 11% 18% 11%	2280
	11th to 20th	Day	48% 7% 10% 21% 12% 2	2296
	21st to end	Day	49% 5% 13% 18% 12% 2	2470
May	1st to 10th	Day	49% 9% 12% 21% 9%	4120
	11th to 20th	Day	43% 8% 15% 24% 9% 1	4085
	21st to end	Day	34% 9% 13% 21% 21% 2	4639
June	1st to 10th	Day	39% 7% 11% 25% 17% 2	2660
	11th to 20th	Day	35% 7% 11% 25% 18% 3	2660
	21st to end	Day	38% 10% 15% 19% 15% 3	2660
July	1st to 10th	Day	44% 4 12% 22% 16% 3	4371
	11th to 20th	Day	31% 4 15% 31% 17% 1	4365
	21st to end	Day	39% 6% 15% 18% 20% 2	4549
August	1st to 10th	Day	36% 6% 15% 27% 16% 1	4091
	11th to 20th	Day	35% 5% 13% 28% 17% 1	4083
	21st to end	Day	32% 5% 14% 30% 17% 3	4189
September	1st to 10th	Day	37% 7% 15% 20% 18% 3	2223
	11th to 20th	Day	31% 7% 12% 27% 21% 1	2090
	21st to end	Day	39% 6% 11% 24% 18% 1	2090
October	1st to 10th	Day	30% 4 10% 36% 20% 1	3480
	11th to 20th	Day	38% 3 12% 22% 24%	3133
	21st to end	Day	45% 4 11% 27% 12% 1	3081
November	1st to 10th	Day	40% 5% 12% 27% 15% 1	1762
	11th to 20th	Day	55% 5% 11% 18% 11% 1	1800
	21st to end	Day	59% 6% 11% 18% 6% 1	1800
December	1st to 10th	Day	64% 5% 12% 13% 5%	1785
	11th to 20th	Day	62% 7% 12% 16% 3	1995
	21st to end	Day	78% 4 7% 6% 4	2807
January	1st to 10th	Night	63% 6% 10% 14% 7%	4428
	11th to 20th	Night	72% 5% 10% 10% 3	4440
	21st to end	Night	72% 4 8% 12% 3	4776
February	1st to 10th	Night	61% 6% 11% 13% 8% 1	2375
	11th to 20th	Night	55% 5% 10% 20% 9% 1	2219
	21st to end	Night	57% 5% 11% 16% 9% 2	1884
March	1st to 10th	Night	51% 5% 11% 24% 9% 1	3733
	11th to 20th	Night	35% 8% 13% 27% 14% 2	3547
	21st to end	Night	50% 7% 15% 21% 7% 1	3756
April	1st to 10th	Night	45% 6% 12% 21% 15% 1	1900
	11th to 20th	Night	47% 6% 10% 18% 17% 2	1833
	21st to end	Night	47% 7% 11% 19% 14% 3	1710
May	1st to 10th	Night	49% 8% 11% 19% 12% 2	2840
	11th to 20th	Night	43% 7% 11% 27% 11% 1	2813
	21st to end	Night	34% 8% 14% 20% 20% 3	2938
June	1st to 10th	Night	31% 6% 13% 29% 18% 3	1520
	11th to 20th	Night	36% 7% 12% 24% 19% 3	1520
	21st to end	Night	36% 8% 16% 22% 15% 3	1520
July	1st to 10th	Night	36% 4 13% 24% 17% 6%	2490
	11th to 20th	Night	26% 5% 17% 27% 24% 2	2482
	21st to end	Night	34% 5% 17% 18% 22% 4	2771
August	1st to 10th	Night	36% 6% 14% 29% 13% 2	2814
	11th to 20th	Night	36% 5% 12% 30% 16% 1	2812
	21st to end	Night	33% 5% 12% 28% 19% 3	3463
September	1st to 10th	Night	31% 7% 13% 23% 21% 5%	1936
	11th to 20th	Night	27% 6% 9% 30% 25% 2	2090
	21st to end	Night	37% 5% 11% 27% 18% 2	2090
October	1st to 10th	Night	23% 3 7% 34% 32% 1	3480
	11th to 20th	Night	38% 3 9% 23% 26% 1	3781
	21st to end	Night	37% 3 9% 31% 18% 1	4467
November	1st to 10th	Night	40% 5% 12% 25% 17% 1	2536
	11th to 20th	Night	50% 5% 12% 21% 11% 2	2600
	21st to end	Night	57% 5% 12% 19% 6%	2600
December	1st to 10th	Night	60% 7% 10% 16% 7%	2610
	11th to 20th	Night	62% 6% 11% 13% 7%	3421
	21st to end	Night	73% 6% 10% 8% 4	4933

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	23% 16% 36% 19% 5% 1	270
	11th to 20th	Day	24% 15% 42% 13% 4 1	270
	21st to end	Day	31% 14% 31% 20% 4	297
February	1st to 10th	Day	25% 17% 35% 19% 3 1	270
	11th to 20th	Day	24% 20% 34% 17% 5%	270
	21st to end	Day	24% 24% 38% 12% 3	225
March	1st to 10th	Day	23% 20% 36% 17% 4	270
	11th to 20th	Day	24% 13% 34% 22% 7% 1	417
	21st to end	Day	30% 13% 30% 19% 6% 2	506
April	1st to 10th	Day	20% 17% 32% 20% 10% 2	460
	11th to 20th	Day	20% 16% 33% 18% 10% 3	452
	21st to end	Day	22% 15% 32% 17% 11% 3	460
May	1st to 10th	Day	23% 12% 31% 22% 10% 3	463
	11th to 20th	Day	22% 8% 26% 23% 14% 6%	487
	21st to end	Day	12% 7% 26% 29% 18% 9%	614
June	1st to 10th	Day	11% 9% 27% 31% 17% 5%	680
	11th to 20th	Day	13% 5% 31% 25% 20% 7%	680
	21st to end	Day	14% 5% 30% 29% 17% 6%	680
July	1st to 10th	Day	11% 3 18% 30% 22% 15%	671
	11th to 20th	Day	10% 3 23% 30% 23% 12%	668
	21st to end	Day	8% 3 21% 31% 25% 12%	673
August	1st to 10th	Day	8% 3 16% 28% 28% 17%	486
	11th to 20th	Day	13% 3 17% 29% 28% 10%	479
	21st to end	Day	11% 2 13% 27% 32% 16%	539
September	1st to 10th	Day	13% 5% 19% 25% 26% 12%	490
	11th to 20th	Day	9% 3 15% 25% 32% 17%	490
	21st to end	Day	19% 8% 19% 24% 23% 7%	490
October	1st to 10th	Day	14% 6% 24% 30% 18% 8%	490
	11th to 20th	Day	18% 14% 28% 29% 10% 1	443
	21st to end	Day	26% 17% 35% 18% 4 2	330
November	1st to 10th	Day	15% 14% 32% 25% 11% 3	300
	11th to 20th	Day	26% 17% 31% 17% 8%	300
	21st to end	Day	29% 15% 38% 15% 3	300
December	1st to 10th	Day	22% 19% 35% 16% 7%	300
	11th to 20th	Day	22% 21% 37% 15% 4	300
	21st to end	Day	27% 20% 37% 14% 3	306
January	1st to 10th	Night	21% 16% 35% 22% 5%	950
	11th to 20th	Night	25% 12% 37% 21% 5% 1	950
	21st to end	Night	22% 14% 36% 23% 4	976
February	1st to 10th	Night	25% 12% 37% 23% 4	760
	11th to 20th	Night	20% 14% 38% 25% 3	743
	21st to end	Night	26% 14% 36% 21% 3	628
March	1st to 10th	Night	19% 13% 36% 25% 6% 1	760
	11th to 20th	Night	16% 12% 38% 28% 5% 1	760
	21st to end	Night	26% 9% 32% 28% 6%	800
April	1st to 10th	Night	19% 12% 34% 27% 7% 1	570
	11th to 20th	Night	20% 9% 35% 28% 7% 1	563
	21st to end	Night	21% 6% 36% 28% 9% 1	570
May	1st to 10th	Night	21% 6% 32% 33% 8%	570
	11th to 20th	Night	20% 5% 27% 34% 14% 1	561
	21st to end	Night	13% 4 25% 38% 19% 2	617
June	1st to 10th	Night	12% 2 26% 43% 16% 1	570
	11th to 20th	Night	10% 4 25% 41% 19% 1	570
	21st to end	Night	9% 3 25% 36% 25% 2	570
July	1st to 10th	Night	9% 3 15% 43% 27% 3	555
	11th to 20th	Night	9% 3 16% 40% 30% 3	552
	21st to end	Night	6% 2 15% 44% 32% 1	624
August	1st to 10th	Night	8% 2 14% 42% 30% 5%	567
	11th to 20th	Night	9% 2 14% 43% 28% 4	564
	21st to end	Night	10% 1 15% 33% 37% 4	627
September	1st to 10th	Night	10% 4 16% 35% 31% 3	606
	11th to 20th	Night	11% 4 12% 37% 33% 3	760
	21st to end	Night	17% 5% 23% 33% 19% 4	760
October	1st to 10th	Night	15% 5% 24% 33% 19% 3	760
	11th to 20th	Night	21% 11% 28% 28% 11% 1	760
	21st to end	Night	25% 12% 30% 25% 7%	836
November	1st to 10th	Night	15% 12% 34% 27% 11% 1	780
	11th to 20th	Night	22% 14% 33% 24% 7% 1	800
	21st to end	Night	24% 14% 32% 25% 6%	800
December	1st to 10th	Night	26% 14% 34% 22% 5%	810
	11th to 20th	Night	26% 13% 35% 22% 5%	1000
	21st to end	Night	29% 14% 32% 21% 3	1063

Page generated at 2024-12-21 04:13:49. Version ac07

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