Raccoon Creek State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Raccoon Creek State Park clear sky chart from 2005-11-06 to 2024-11-10.

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	16% 10% 4 8% 5% 5% 5% 4 5% 7% 32%	101121
	Night	17% 11% 4 8% 5% 4 4 3 5% 6% 33%	97967
Transparency	Day	50% 6% 11% 21% 11% 1	104771
	Night	50% 6% 10% 21% 12% 2	102456
Seeing	Day	23% 15% 27% 20% 11% 4	14722
	Night	22% 12% 26% 26% 12% 1	24461

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	19% 21% 8% 11% 4 3 3 3 3 5% 19%	2836
	11th to 20th	Day	13% 23% 9% 13% 6% 4 3 3 3 4 18%	2840
	21st to end	Day	25% 21% 7% 12% 6% 4 3 2 3 3 13%	3124
February	1st to 10th	Day	19% 18% 5% 10% 6% 4 4 3 3 5% 24%	1710
	11th to 20th	Day	16% 14% 7% 13% 5% 5% 3 3 5% 5% 23%	1663
	21st to end	Day	19% 16% 4 10% 5% 4 3 3 4 4 27%	1579
March	1st to 10th	Day	21% 14% 5% 8% 4 4 4 3 4 6% 27%	3435
	11th to 20th	Day	13% 11% 4 9% 5% 6% 5% 3 4 6% 34%	3480
	21st to end	Day	21% 10% 3 8% 4 4 4 4 5% 6% 32%	3815
April	1st to 10th	Day	15% 15% 3 8% 4 4 4 3 5% 7% 31%	2171
	11th to 20th	Day	18% 11% 3 6% 5% 5% 4 3 5% 5% 34%	2313
	21st to end	Day	22% 9% 3 6% 4 5% 4 3 5% 6% 33%	2470
May	1st to 10th	Day	25% 9% 3 7% 4 5% 5% 4 5% 6% 28%	4082
	11th to 20th	Day	21% 7% 3 8% 5% 4 4 4 5% 7% 31%	4081
	21st to end	Day	14% 6% 2 6% 4 5% 5% 4 7% 10% 37%	4657
June	1st to 10th	Day	13% 8% 3 7% 5% 5% 6% 5% 6% 9% 34%	2660
	11th to 20th	Day	15% 7% 2 6% 5% 5% 4 4 6% 9% 36%	2660
	21st to end	Day	14% 6% 2 5% 5% 5% 5% 4 7% 10% 37%	2660
July	1st to 10th	Day	9% 6% 2 6% 5% 5% 6% 5% 6% 9% 40%	4219
	11th to 20th	Day	10% 6% 2 7% 5% 5% 5% 4 6% 10% 41%	4120
	21st to end	Day	12% 7% 3 7% 5% 5% 6% 5% 6% 8% 36%	4466
August	1st to 10th	Day	14% 7% 3 8% 6% 5% 6% 5% 6% 9% 32%	4104
	11th to 20th	Day	12% 6% 2 7% 5% 5% 6% 4 7% 10% 35%	4044
	21st to end	Day	8% 5% 2 7% 5% 7% 6% 5% 7% 9% 41%	4346
September	1st to 10th	Day	16% 6% 2 4 3 4 4 3 5% 7% 46%	2256
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 6% 9% 45%	2090
	21st to end	Day	20% 7% 3 7% 4 4 5% 4 4 6% 37%	2090
October	1st to 10th	Day	15% 7% 2 6% 4 4 5% 4 6% 8% 41%	1915
	11th to 20th	Day	19% 9% 3 7% 4 5% 5% 3 4 5% 36%	1900
	21st to end	Day	22% 11% 2 6% 4 4 4 3 5% 7% 33%	2090
November	1st to 10th	Day	11% 8% 2 6% 5% 5% 5% 4 5% 6% 43%	1843
	11th to 20th	Day	17% 14% 4 7% 5% 4 4 3 5% 5% 32%	1620
	21st to end	Day	16% 16% 6% 8% 4 5% 6% 3 5% 6% 26%	1520
December	1st to 10th	Day	21% 18% 7% 11% 5% 4 4 4 4 5% 18%	1520
	11th to 20th	Day	19% 18% 7% 12% 5% 4 3 3 4 6% 20%	1910
	21st to end	Day	25% 22% 6% 11% 5% 3 4 2 5% 4 13%	2832
January	1st to 10th	Night	16% 21% 8% 12% 5% 5% 4 3 4 4 19%	4109
	11th to 20th	Night	18% 18% 8% 13% 6% 5% 4 3 4 4 16%	4120
	21st to end	Night	28% 17% 7% 12% 6% 3 3 2 3 3 16%	4532
February	1st to 10th	Night	19% 16% 4 11% 5% 3 3 4 4 4 25%	2470
	11th to 20th	Night	18% 13% 5% 13% 5% 4 4 3 4 5% 25%	2403
	21st to end	Night	20% 14% 5% 11% 6% 4 4 3 5% 5% 24%	1872
March	1st to 10th	Night	23% 13% 4 7% 4 3 3 2 4 6% 33%	3418
	11th to 20th	Night	17% 13% 6% 8% 3 3 3 2 4 6% 33%	3480
	21st to end	Night	19% 11% 3 7% 4 4 3 3 4 5% 38%	3817
April	1st to 10th	Night	18% 12% 3 7% 5% 5% 4 3 5% 7% 34%	2007
	11th to 20th	Night	17% 9% 3 7% 5% 4 4 3 5% 7% 37%	1832
	21st to end	Night	16% 10% 3 7% 4 3 4 3 7% 7% 37%	1710
May	1st to 10th	Night	27% 10% 3 7% 4 4 4 3 5% 6% 27%	2813
	11th to 20th	Night	18% 8% 3 6% 4 4 4 3 5% 7% 38%	2812
	21st to end	Night	11% 6% 1 5% 4 4 5% 4 7% 10% 43%	2894
June	1st to 10th	Night	10% 6% 3 7% 5% 4 4 4 6% 9% 44%	1520
	11th to 20th	Night	12% 6% 2 6% 4 5% 4 4 6% 10% 42%	1520
	21st to end	Night	10% 4 2 5% 5% 5% 6% 4 6% 8% 45%	1520
July	1st to 10th	Night	11% 8% 2 7% 4 5% 4 4 6% 8% 42%	2734
	11th to 20th	Night	9% 5% 2 6% 4 4 5% 4 6% 9% 45%	2840
	21st to end	Night	10% 6% 3 8% 5% 5% 5% 4 6% 6% 42%	3087
August	1st to 10th	Night	13% 8% 3 7% 5% 5% 5% 5% 7% 8% 35%	2825
	11th to 20th	Night	12% 8% 2 7% 4 4 4 4 5% 7% 43%	2785
	21st to end	Night	8% 5% 2 6% 4 5% 6% 5% 6% 9% 44%	3276
September	1st to 10th	Night	14% 4 1 5% 3 3 3 4 5% 6% 51%	1921
	11th to 20th	Night	10% 4 1 4 3 3 4 3 4 9% 53%	2090
	21st to end	Night	17% 7% 2 6% 4 4 4 4 4 6% 42%	2090
October	1st to 10th	Night	14% 6% 2 6% 4 4 4 4 5% 6% 46%	2264
	11th to 20th	Night	17% 7% 2 7% 5% 4 5% 3 5% 5% 39%	2280
	21st to end	Night	24% 7% 3 6% 3 3 4 3 4 7% 37%	2508
November	1st to 10th	Night	13% 8% 3 5% 4 4 3 3 5% 6% 46%	2437
	11th to 20th	Night	19% 12% 3 6% 4 4 4 4 5% 6% 33%	2556
	21st to end	Night	19% 13% 4 8% 4 5% 4 4 4 6% 29%	2660
December	1st to 10th	Night	23% 17% 7% 9% 4 3 4 3 4 6% 20%	2660
	11th to 20th	Night	19% 18% 6% 11% 4 3 3 3 5% 5% 24%	3285
	21st to end	Night	25% 20% 6% 9% 5% 4 4 3 4 5% 14%	4820

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	68% 6% 10% 12% 5%	2837
	11th to 20th	Day	72% 4 7% 12% 4 1	2840
	21st to end	Day	77% 4 7% 9% 2	3124
February	1st to 10th	Day	65% 5% 9% 14% 7% 1	1710
	11th to 20th	Day	63% 5% 8% 16% 8%	1672
	21st to end	Day	61% 4 11% 16% 8% 2	1579
March	1st to 10th	Day	57% 6% 9% 22% 6%	3435
	11th to 20th	Day	51% 5% 10% 24% 8% 1	3480
	21st to end	Day	52% 5% 9% 20% 12% 1	3815
April	1st to 10th	Day	52% 7% 10% 19% 11% 2	2171
	11th to 20th	Day	50% 6% 9% 17% 15% 2	2313
	21st to end	Day	51% 6% 9% 22% 10% 2	2470
May	1st to 10th	Day	55% 7% 9% 20% 8% 1	4120
	11th to 20th	Day	51% 7% 10% 21% 9% 1	4085
	21st to end	Day	40% 9% 13% 23% 12% 3	4671
June	1st to 10th	Day	44% 8% 13% 21% 12% 1	2660
	11th to 20th	Day	43% 8% 12% 23% 12% 1	2660
	21st to end	Day	41% 8% 13% 24% 13% 1	2660
July	1st to 10th	Day	39% 8% 12% 23% 15% 3	4154
	11th to 20th	Day	37% 6% 12% 28% 16% 1	4051
	21st to end	Day	44% 7% 11% 20% 16% 2	4324
August	1st to 10th	Day	47% 8% 12% 22% 10%	4091
	11th to 20th	Day	41% 7% 12% 29% 11%	4083
	21st to end	Day	37% 7% 12% 27% 13% 2	4346
September	1st to 10th	Day	39% 6% 10% 22% 19% 3	2256
	11th to 20th	Day	36% 6% 13% 27% 15% 2	2090
	21st to end	Day	49% 5% 9% 22% 15%	2090
October	1st to 10th	Day	33% 5% 9% 32% 21% 1	3175
	11th to 20th	Day	45% 5% 10% 21% 14% 5%	3140
	21st to end	Day	38% 4 12% 27% 18% 1	3428
November	1st to 10th	Day	41% 5% 11% 23% 17% 2	1843
	11th to 20th	Day	54% 4 9% 20% 10% 2	1620
	21st to end	Day	57% 7% 11% 16% 8% 1	1520
December	1st to 10th	Day	69% 6% 9% 12% 4	1520
	11th to 20th	Day	66% 4 10% 17% 4	1906
	21st to end	Day	74% 5% 9% 9% 3	2832
January	1st to 10th	Night	69% 4 9% 14% 4	4109
	11th to 20th	Night	72% 5% 9% 10% 3	4120
	21st to end	Night	75% 3 6% 12% 3	4532
February	1st to 10th	Night	62% 5% 8% 17% 7%	2470
	11th to 20th	Night	62% 4 9% 17% 7%	2405
	21st to end	Night	63% 4 8% 15% 9% 1	1872
March	1st to 10th	Night	54% 4 9% 23% 9%	3418
	11th to 20th	Night	51% 5% 11% 25% 7% 1	3480
	21st to end	Night	48% 5% 9% 23% 12% 2	3817
April	1st to 10th	Night	50% 6% 10% 19% 13% 2	2007
	11th to 20th	Night	47% 6% 11% 17% 16% 3	1832
	21st to end	Night	45% 5% 11% 22% 13% 3	1710
May	1st to 10th	Night	57% 7% 6% 18% 10% 2	2840
	11th to 20th	Night	46% 9% 10% 25% 10% 1	2813
	21st to end	Night	34% 10% 14% 25% 13% 4	2901
June	1st to 10th	Night	37% 9% 11% 24% 17% 2	1520
	11th to 20th	Night	38% 7% 14% 24% 15% 2	1520
	21st to end	Night	35% 9% 12% 24% 17% 2	1520
July	1st to 10th	Night	41% 6% 10% 23% 17% 3	2689
	11th to 20th	Night	34% 8% 14% 28% 16% 1	2786
	21st to end	Night	40% 8% 10% 18% 21% 3	2988
August	1st to 10th	Night	45% 9% 12% 23% 11%	2814
	11th to 20th	Night	40% 6% 10% 26% 17% 1	2812
	21st to end	Night	35% 7% 12% 30% 13% 2	3276
September	1st to 10th	Night	34% 6% 10% 24% 21% 5%	1921
	11th to 20th	Night	30% 6% 12% 27% 24% 1	2090
	21st to end	Night	44% 5% 10% 21% 19% 1	2090
October	1st to 10th	Night	35% 4 8% 27% 24% 2	3784
	11th to 20th	Night	38% 5% 10% 23% 15% 8%	3779
	21st to end	Night	35% 4 9% 29% 21% 2	4120
November	1st to 10th	Night	40% 4 11% 24% 17% 4	2437
	11th to 20th	Night	52% 4 10% 20% 11% 2	2556
	21st to end	Night	56% 4 11% 21% 7% 1	2660
December	1st to 10th	Night	66% 4 10% 14% 5%	2660
	11th to 20th	Night	64% 4 11% 17% 4	3288
	21st to end	Night	72% 6% 9% 10% 3	4820

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	34% 25% 25% 11% 4	270
	11th to 20th	Day	37% 27% 26% 7% 1	270
	21st to end	Day	31% 32% 28% 6% 3	297
February	1st to 10th	Day	36% 21% 34% 8% 1	270
	11th to 20th	Day	37% 31% 26% 5% 1	270
	21st to end	Day	40% 27% 26% 7%	235
March	1st to 10th	Day	30% 20% 30% 16% 3	460
	11th to 20th	Day	32% 21% 30% 12% 5% 1	460
	21st to end	Day	32% 22% 27% 15% 4	506
April	1st to 10th	Day	32% 19% 26% 15% 7% 2	460
	11th to 20th	Day	26% 20% 27% 16% 8% 3	452
	21st to end	Day	30% 17% 32% 14% 6% 2	460
May	1st to 10th	Day	28% 21% 25% 17% 6% 3	463
	11th to 20th	Day	22% 15% 33% 18% 9% 4	487
	21st to end	Day	16% 10% 27% 24% 17% 6%	529
June	1st to 10th	Day	14% 10% 31% 27% 15% 3	490
	11th to 20th	Day	18% 11% 24% 29% 14% 4	490
	21st to end	Day	13% 12% 33% 25% 14% 3	490
July	1st to 10th	Day	13% 7% 22% 27% 21% 10%	485
	11th to 20th	Day	12% 6% 28% 28% 18% 8%	484
	21st to end	Day	11% 8% 25% 30% 18% 7%	532
August	1st to 10th	Day	13% 8% 22% 31% 19% 8%	486
	11th to 20th	Day	15% 8% 22% 29% 17% 9%	479
	21st to end	Day	11% 5% 23% 28% 22% 11%	539
September	1st to 10th	Day	17% 8% 21% 27% 21% 6%	490
	11th to 20th	Day	12% 5% 20% 30% 22% 11%	490
	21st to end	Day	24% 11% 25% 22% 14% 4	490
October	1st to 10th	Day	16% 10% 30% 23% 16% 5%	490
	11th to 20th	Day	23% 18% 27% 22% 8% 2	490
	21st to end	Day	29% 16% 31% 18% 6%	539
November	1st to 10th	Day	21% 16% 35% 16% 10% 3	387
	11th to 20th	Day	34% 17% 26% 16% 6% 1	228
	21st to end	Day	27% 22% 39% 11% 1	180
December	1st to 10th	Day	31% 27% 27% 10% 3 2	180
	11th to 20th	Day	31% 23% 34% 11% 2	180
	21st to end	Day	36% 24% 27% 11% 3	214
January	1st to 10th	Night	30% 19% 33% 15% 2	760
	11th to 20th	Night	32% 18% 31% 16% 3	760
	21st to end	Night	28% 21% 29% 19% 3	836
February	1st to 10th	Night	32% 16% 29% 21% 3	760
	11th to 20th	Night	29% 22% 33% 14% 1	743
	21st to end	Night	28% 20% 31% 18% 2	628
March	1st to 10th	Night	26% 18% 31% 22% 3	760
	11th to 20th	Night	27% 18% 27% 22% 5% 1	760
	21st to end	Night	27% 16% 32% 20% 5%	836
April	1st to 10th	Night	25% 16% 30% 23% 6%	760
	11th to 20th	Night	23% 14% 31% 22% 9% 1	708
	21st to end	Night	20% 11% 35% 29% 6%	570
May	1st to 10th	Night	23% 9% 26% 32% 9% 2	570
	11th to 20th	Night	20% 8% 28% 29% 14% 1	561
	21st to end	Night	12% 3 23% 36% 24% 3	509
June	1st to 10th	Night	11% 6% 24% 42% 18%	380
	11th to 20th	Night	13% 5% 23% 38% 20% 1	380
	21st to end	Night	10% 4 28% 34% 23% 1	380
July	1st to 10th	Night	8% 3 18% 40% 24% 7%	488
	11th to 20th	Night	9% 2 21% 38% 26% 4	552
	21st to end	Night	12% 4 14% 42% 27% 2	624
August	1st to 10th	Night	10% 2 17% 40% 28% 3	567
	11th to 20th	Night	12% 4 12% 39% 29% 4	564
	21st to end	Night	11% 4 19% 31% 30% 5%	714
September	1st to 10th	Night	15% 3 19% 33% 25% 4	760
	11th to 20th	Night	11% 4 16% 36% 29% 4	760
	21st to end	Night	19% 8% 23% 26% 21% 3	760
October	1st to 10th	Night	16% 8% 24% 29% 21% 2	760
	11th to 20th	Night	21% 12% 30% 25% 11% 1	760
	21st to end	Night	28% 13% 27% 25% 7%	836
November	1st to 10th	Night	17% 12% 29% 29% 13%	779
	11th to 20th	Night	29% 13% 28% 23% 7% 1	760
	21st to end	Night	29% 14% 30% 21% 6%	760
December	1st to 10th	Night	33% 19% 26% 18% 4	760
	11th to 20th	Night	28% 19% 29% 20% 3	760
	21st to end	Night	31% 17% 30% 19% 2	836

Page generated at 2024-11-07 06:55:43. Version ac07

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