Caesar Creek State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caesar Creek State Park clear sky chart from 2005-11-06 to 2025-06-10.

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	14% 9% 4 8% 5% 4 5% 4 5% 7% 35%	120132
	Night	15% 10% 4 8% 5% 4 4 3 5% 7% 36%	117992
Transparency	Day	47% 5% 11% 22% 14% 2	123814
	Night	47% 4 10% 22% 14% 2	122447
Seeing	Day	17% 9% 26% 24% 16% 7%	16051
	Night	18% 8% 27% 31% 15% 2	25662

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	15% 18% 8% 13% 4 4 4 3 4 4 23%	3745
	11th to 20th	Day	14% 15% 6% 14% 7% 6% 5% 3 3 4 24%	4060
	21st to end	Day	22% 13% 7% 10% 5% 5% 5% 3 4 5% 21%	4466
February	1st to 10th	Day	19% 14% 5% 11% 5% 5% 4 2 4 5% 25%	1867
	11th to 20th	Day	17% 12% 4 11% 7% 5% 4 3 5% 6% 27%	1948
	21st to end	Day	17% 14% 5% 9% 4 4 4 3 4 4 30%	1650
March	1st to 10th	Day	17% 13% 7% 10% 5% 4 4 3 4 4 30%	4566
	11th to 20th	Day	13% 8% 3 7% 5% 4 3 4 5% 8% 40%	4980
	21st to end	Day	17% 10% 4 7% 5% 4 4 3 6% 7% 33%	5465
April	1st to 10th	Day	15% 11% 3 8% 5% 4 4 3 6% 7% 33%	2329
	11th to 20th	Day	15% 9% 3 7% 5% 5% 4 3 5% 6% 38%	2457
	21st to end	Day	18% 8% 3 7% 5% 4 5% 4 5% 7% 35%	2600
May	1st to 10th	Day	20% 9% 3 8% 5% 5% 5% 4 6% 7% 30%	5862
	11th to 20th	Day	19% 8% 3 7% 4 4 4 4 5% 7% 33%	5861
	21st to end	Day	14% 7% 3 7% 5% 5% 5% 4 7% 10% 32%	6433
June	1st to 10th	Day	12% 6% 3 6% 5% 4 6% 4 7% 8% 39%	2587
	11th to 20th	Day	9% 5% 2 6% 5% 5% 5% 5% 6% 10% 42%	2621
	21st to end	Day	10% 6% 2 6% 5% 5% 5% 5% 7% 10% 39%	2660
July	1st to 10th	Day	11% 6% 2 7% 5% 5% 5% 4 7% 10% 37%	4440
	11th to 20th	Day	7% 5% 2 5% 4 4 5% 4 7% 11% 45%	4221
	21st to end	Day	11% 7% 2 7% 6% 6% 6% 6% 7% 9% 34%	4466
August	1st to 10th	Day	9% 6% 2 5% 4 4 5% 4 7% 10% 42%	4104
	11th to 20th	Day	8% 5% 2 7% 4 5% 5% 4 8% 10% 39%	4044
	21st to end	Day	7% 4 2 5% 3 4 4 3 5% 9% 54%	4282
September	1st to 10th	Day	12% 6% 2 4 4 4 5% 4 5% 6% 48%	2144
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 6% 10% 48%	2090
	21st to end	Day	15% 7% 2 6% 4 3 3 3 5% 7% 45%	2090
October	1st to 10th	Day	11% 5% 2 6% 5% 4 4 3 5% 7% 48%	2090
	11th to 20th	Day	15% 7% 2 5% 4 3 4 3 5% 6% 46%	1905
	21st to end	Day	20% 8% 3 6% 4 4 3 3 4 7% 37%	1968
November	1st to 10th	Day	10% 6% 2 5% 5% 4 4 3 4 7% 50%	1762
	11th to 20th	Day	14% 12% 5% 8% 4 4 5% 3 5% 6% 34%	1800
	21st to end	Day	18% 12% 3 8% 6% 4 4 2 4 6% 33%	1800
December	1st to 10th	Day	17% 11% 4 8% 5% 4 3 4 4 5% 35%	2930
	11th to 20th	Day	19% 16% 5% 10% 5% 4 4 4 4 4 24%	3373
	21st to end	Day	21% 20% 6% 11% 5% 4 4 3 4 5% 17%	4466
January	1st to 10th	Night	15% 17% 7% 14% 8% 5% 4 3 4 5% 19%	6067
	11th to 20th	Night	13% 17% 7% 14% 7% 6% 5% 3 4 5% 20%	5900
	21st to end	Night	21% 14% 5% 8% 5% 5% 3 2 3 4 28%	6490
February	1st to 10th	Night	21% 13% 5% 8% 5% 4 4 3 4 5% 28%	2530
	11th to 20th	Night	17% 12% 4 9% 5% 4 4 4 4 6% 30%	2338
	21st to end	Night	20% 14% 5% 8% 4 3 3 3 3 5% 31%	1980
March	1st to 10th	Night	18% 13% 3 7% 4 4 4 3 4 5% 37%	5286
	11th to 20th	Night	11% 7% 3 6% 5% 4 5% 4 6% 8% 42%	4980
	21st to end	Night	18% 9% 4 8% 5% 4 4 4 4 5% 34%	5467
April	1st to 10th	Night	16% 9% 2 6% 5% 4 4 4 5% 7% 38%	2088
	11th to 20th	Night	14% 7% 2 7% 5% 3 4 4 6% 8% 40%	1892
	21st to end	Night	16% 8% 3 7% 4 3 4 4 6% 8% 38%	1800
May	1st to 10th	Night	22% 10% 3 8% 5% 5% 4 4 6% 7% 27%	4033
	11th to 20th	Night	16% 7% 3 7% 4 4 5% 4 7% 9% 35%	4032
	21st to end	Night	13% 7% 2 7% 4 5% 5% 4 7% 8% 39%	4421
June	1st to 10th	Night	8% 6% 2 5% 4 4 4 4 5% 8% 49%	1797
	11th to 20th	Night	8% 4 1 5% 4 4 5% 3 9% 11% 46%	1553
	21st to end	Night	6% 5% 1 4 5% 5% 6% 6% 8% 10% 45%	1520
July	1st to 10th	Night	11% 5% 2 5% 3 4 4 4 5% 9% 48%	2530
	11th to 20th	Night	7% 4 1 5% 4 4 4 4 6% 9% 52%	2737
	21st to end	Night	11% 7% 2 7% 5% 5% 5% 4 7% 9% 39%	3087
August	1st to 10th	Night	8% 7% 2 7% 5% 5% 5% 4 7% 8% 43%	2825
	11th to 20th	Night	8% 8% 3 7% 4 4 4 3 6% 8% 45%	2785
	21st to end	Night	4 3 1 5% 3 4 4 3 6% 10% 56%	3370
September	1st to 10th	Night	12% 5% 2 4 3 4 4 3 5% 7% 51%	2015
	11th to 20th	Night	9% 4 1 5% 3 3 4 3 5% 7% 54%	2090
	21st to end	Night	13% 7% 2 5% 4 3 3 2 5% 6% 49%	2090
October	1st to 10th	Night	9% 5% 2 6% 4 4 3 3 5% 6% 54%	2090
	11th to 20th	Night	15% 7% 3 7% 4 4 3 3 5% 7% 44%	2274
	21st to end	Night	19% 8% 2 6% 4 4 4 3 5% 6% 40%	2627
November	1st to 10th	Night	14% 7% 2 6% 4 3 3 3 4 7% 46%	2536
	11th to 20th	Night	16% 9% 3 7% 4 4 5% 3 5% 6% 38%	2600
	21st to end	Night	18% 13% 4 7% 5% 4 4 3 5% 7% 30%	2600
December	1st to 10th	Night	16% 11% 4 10% 4 4 3 3 5% 5% 36%	4250
	11th to 20th	Night	19% 15% 7% 9% 5% 4 3 3 4 5% 25%	4822
	21st to end	Night	21% 20% 6% 10% 6% 4 4 3 4 5% 16%	6490

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	65% 4 8% 17% 7%	3746
	11th to 20th	Day	66% 3 8% 11% 10% 1	4060
	21st to end	Day	67% 3 10% 12% 7% 2	4466
February	1st to 10th	Day	62% 4 9% 14% 9% 1	1867
	11th to 20th	Day	59% 4 11% 16% 9%	1958
	21st to end	Day	57% 5% 10% 19% 8% 1	1650
March	1st to 10th	Day	59% 3 6% 19% 11% 2	4566
	11th to 20th	Day	42% 4 10% 27% 15% 1	4980
	21st to end	Day	51% 4 12% 20% 11% 3	5465
April	1st to 10th	Day	49% 6% 11% 22% 12% 1	2329
	11th to 20th	Day	47% 5% 11% 21% 13% 3	2457
	21st to end	Day	48% 6% 11% 22% 11% 2	2600
May	1st to 10th	Day	54% 5% 12% 18% 11%	5897
	11th to 20th	Day	50% 6% 11% 24% 9%	5865
	21st to end	Day	44% 7% 13% 22% 12% 1	6447
June	1st to 10th	Day	40% 8% 12% 22% 16% 2	2587
	11th to 20th	Day	37% 8% 15% 23% 17% 1	2621
	21st to end	Day	38% 8% 16% 20% 15% 3	2660
July	1st to 10th	Day	42% 6% 12% 22% 17% 2	4371
	11th to 20th	Day	33% 6% 10% 32% 19% 1	4148
	21st to end	Day	44% 6% 14% 19% 14% 4	4324
August	1st to 10th	Day	36% 6% 16% 30% 11% 1	4091
	11th to 20th	Day	37% 5% 11% 30% 16% 1	4083
	21st to end	Day	29% 5% 14% 31% 19% 3	4281
September	1st to 10th	Day	35% 7% 10% 24% 21% 5%	2144
	11th to 20th	Day	33% 5% 12% 26% 22% 3	2090
	21st to end	Day	40% 5% 10% 22% 22% 2	2090
October	1st to 10th	Day	25% 4 9% 30% 30% 2	3480
	11th to 20th	Day	31% 3 9% 30% 25% 1	3145
	21st to end	Day	38% 2 11% 24% 23% 2	3218
November	1st to 10th	Day	35% 4 10% 28% 20% 3	1762
	11th to 20th	Day	51% 4 10% 19% 15% 2	1800
	21st to end	Day	54% 4 10% 21% 11% 1	1800
December	1st to 10th	Day	53% 3 10% 26% 8%	2930
	11th to 20th	Day	64% 4 9% 17% 6%	3370
	21st to end	Day	71% 4 10% 11% 5%	4466
January	1st to 10th	Night	68% 4 8% 13% 7%	6067
	11th to 20th	Night	67% 3 9% 12% 8% 2	5900
	21st to end	Night	61% 2 9% 18% 8% 1	6490
February	1st to 10th	Night	59% 4 10% 18% 8% 1	2530
	11th to 20th	Night	56% 4 10% 18% 11% 1	2339
	21st to end	Night	57% 4 11% 16% 10% 2	1980
March	1st to 10th	Night	50% 4 7% 26% 11% 2	5286
	11th to 20th	Night	39% 5% 11% 29% 14% 1	4980
	21st to end	Night	51% 4 8% 24% 12% 1	5467
April	1st to 10th	Night	45% 5% 13% 23% 11% 2	2088
	11th to 20th	Night	41% 5% 13% 19% 18% 4	1892
	21st to end	Night	44% 6% 11% 24% 13% 3	1800
May	1st to 10th	Night	56% 5% 9% 18% 7% 3	4060
	11th to 20th	Night	44% 6% 14% 24% 11% 1	4033
	21st to end	Night	40% 6% 16% 25% 9% 3	4429
June	1st to 10th	Night	33% 7% 11% 26% 21% 2	1797
	11th to 20th	Night	29% 8% 18% 22% 19% 4	1553
	21st to end	Night	31% 9% 17% 21% 17% 5%	1520
July	1st to 10th	Night	35% 6% 11% 24% 18% 5%	2490
	11th to 20th	Night	29% 5% 13% 33% 19% 2	2687
	21st to end	Night	40% 5% 14% 22% 15% 4	2988
August	1st to 10th	Night	37% 7% 13% 29% 12% 1	2814
	11th to 20th	Night	37% 4 11% 27% 20% 1	2812
	21st to end	Night	25% 5% 16% 30% 21% 3	3370
September	1st to 10th	Night	32% 6% 13% 24% 19% 6%	2015
	11th to 20th	Night	28% 6% 10% 26% 27% 4	2090
	21st to end	Night	36% 5% 10% 21% 25% 2	2090
October	1st to 10th	Night	23% 3 7% 29% 34% 3	3480
	11th to 20th	Night	30% 3 9% 26% 30% 2	3773
	21st to end	Night	34% 3 8% 24% 26% 5%	4327
November	1st to 10th	Night	38% 4 12% 22% 21% 3	2536
	11th to 20th	Night	46% 4 9% 22% 16% 3	2600
	21st to end	Night	55% 4 11% 20% 9% 1	2600
December	1st to 10th	Night	52% 3 11% 25% 9%	4250
	11th to 20th	Night	62% 3 11% 16% 7%	4824
	21st to end	Night	71% 3 8% 14% 3	6490

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% 17% 37% 18% 5%	300
	11th to 20th	Day	26% 20% 36% 14% 3	300
	21st to end	Day	30% 17% 32% 16% 4	330
February	1st to 10th	Day	26% 16% 36% 18% 3	300
	11th to 20th	Day	27% 21% 34% 15% 3	300
	21st to end	Day	24% 16% 46% 11% 2	249
March	1st to 10th	Day	22% 19% 38% 17% 4	334
	11th to 20th	Day	22% 15% 35% 20% 8% 1	500
	21st to end	Day	27% 16% 33% 19% 5%	550
April	1st to 10th	Day	21% 15% 33% 20% 9% 2	500
	11th to 20th	Day	20% 17% 27% 23% 10% 3	492
	21st to end	Day	22% 10% 34% 21% 10% 2	500
May	1st to 10th	Day	23% 12% 30% 23% 8% 4	503
	11th to 20th	Day	21% 8% 25% 24% 14% 7%	527
	21st to end	Day	14% 5% 23% 28% 19% 11%	573
June	1st to 10th	Day	13% 4 21% 32% 21% 9%	526
	11th to 20th	Day	10% 4 21% 32% 25% 8%	641
	21st to end	Day	10% 5% 25% 31% 20% 9%	680
July	1st to 10th	Day	13% 3 16% 25% 24% 19%	671
	11th to 20th	Day	10% 3 20% 26% 26% 15%	542
	21st to end	Day	11% 2 14% 30% 28% 15%	532
August	1st to 10th	Day	10% 2 13% 26% 29% 20%	486
	11th to 20th	Day	11% 4 16% 31% 24% 13%	479
	21st to end	Day	9% 3 12% 26% 32% 18%	539
September	1st to 10th	Day	13% 3 13% 23% 33% 15%	490
	11th to 20th	Day	9% 3 12% 27% 34% 15%	490
	21st to end	Day	19% 9% 18% 24% 22% 9%	490
October	1st to 10th	Day	10% 4 21% 35% 20% 10%	490
	11th to 20th	Day	15% 12% 31% 23% 15% 5%	490
	21st to end	Day	22% 10% 35% 25% 7% 1	417
November	1st to 10th	Day	14% 9% 35% 25% 11% 5%	300
	11th to 20th	Day	20% 17% 30% 20% 10% 2	300
	21st to end	Day	25% 12% 37% 22% 4	300
December	1st to 10th	Day	21% 18% 36% 18% 7% 1	300
	11th to 20th	Day	23% 13% 41% 19% 5%	300
	21st to end	Day	29% 18% 32% 16% 5%	330
January	1st to 10th	Night	21% 16% 35% 22% 6%	888
	11th to 20th	Night	27% 14% 35% 21% 3	800
	21st to end	Night	22% 12% 38% 25% 3	880
February	1st to 10th	Night	27% 9% 35% 26% 3	800
	11th to 20th	Night	25% 14% 35% 24% 2	783
	21st to end	Night	27% 11% 38% 22% 2	660
March	1st to 10th	Night	20% 12% 35% 27% 5%	800
	11th to 20th	Night	20% 13% 34% 27% 6% 1	800
	21st to end	Night	23% 11% 32% 27% 7%	880
April	1st to 10th	Night	20% 11% 32% 30% 5% 1	688
	11th to 20th	Night	17% 9% 33% 30% 10% 1	593
	21st to end	Night	18% 8% 37% 29% 9% 1	600
May	1st to 10th	Night	22% 7% 30% 29% 11% 1	600
	11th to 20th	Night	18% 4 24% 34% 16% 3	591
	21st to end	Night	10% 3 20% 36% 26% 4	650
June	1st to 10th	Night	10% 2 19% 45% 23% 1	599
	11th to 20th	Night	9% 3 16% 43% 27% 2	570
	21st to end	Night	6% 3 20% 43% 26% 2	570
July	1st to 10th	Night	11% 2 10% 37% 31% 9%	555
	11th to 20th	Night	7% 3 10% 40% 35% 6%	552
	21st to end	Night	11% 2 11% 41% 32% 4	624
August	1st to 10th	Night	8% 2 10% 38% 37% 4	567
	11th to 20th	Night	9% 1 11% 43% 32% 4	564
	21st to end	Night	7% 2 11% 32% 40% 8%	627
September	1st to 10th	Night	14% 2 14% 31% 34% 5%	685
	11th to 20th	Night	10% 3 11% 35% 36% 5%	760
	21st to end	Night	16% 4 19% 36% 24% 2	760
October	1st to 10th	Night	11% 4 23% 36% 22% 5%	760
	11th to 20th	Night	18% 8% 26% 33% 14% 1	760
	21st to end	Night	22% 7% 33% 28% 11%	836
November	1st to 10th	Night	17% 7% 30% 30% 16% 1	780
	11th to 20th	Night	19% 12% 32% 28% 9% 1	800
	21st to end	Night	24% 11% 28% 30% 7%	800
December	1st to 10th	Night	26% 11% 33% 25% 6%	800
	11th to 20th	Night	26% 9% 34% 25% 6% 1	800
	21st to end	Night	29% 14% 29% 26% 3	880

Page generated at 2025-06-07 10:28:17. Version ac07

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