Eisenhower State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eisenhower State Park clear sky chart from 2005-11-06 to 2024-11-05.

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	11% 5% 2 5% 4 4 4 3 5% 7% 51%	101192
	Night	11% 5% 2 4 3 3 3 3 5% 6% 56%	97942
Transparency	Day	32% 5% 9% 25% 22% 7%	104922
	Night	28% 4 9% 24% 25% 10%	102339
Seeing	Day	12% 7% 23% 28% 23% 7%	15244
	Night	12% 8% 29% 34% 16% 1	25086

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	12% 8% 2 5% 4 3 3 3 4 6% 51%	2847
	11th to 20th	Day	10% 6% 2 3 2 2 2 3 4 5% 63%	2850
	21st to end	Day	19% 10% 3 6% 3 2 2 2 3 4 47%	3135
February	1st to 10th	Day	17% 7% 3 7% 4 4 3 3 3 4 46%	1776
	11th to 20th	Day	14% 7% 2 6% 4 4 3 3 4 5% 47%	1849
	21st to end	Day	20% 8% 3 5% 2 2 2 1 3 4 50%	1598
March	1st to 10th	Day	15% 6% 2 5% 3 3 3 3 4 5% 51%	3436
	11th to 20th	Day	14% 7% 3 5% 4 5% 5% 4 5% 5% 44%	3480
	21st to end	Day	15% 8% 3 6% 5% 3 4 3 5% 6% 41%	3814
April	1st to 10th	Day	13% 6% 2 5% 3 4 3 3 4 5% 51%	2090
	11th to 20th	Day	12% 6% 2 6% 5% 4 4 3 6% 5% 48%	2192
	21st to end	Day	13% 6% 2 6% 4 3 4 4 6% 6% 47%	2422
May	1st to 10th	Day	16% 7% 3 7% 4 4 4 3 5% 6% 42%	4082
	11th to 20th	Day	13% 6% 2 6% 4 3 4 3 5% 6% 48%	4082
	21st to end	Day	15% 7% 3 7% 5% 5% 4 4 5% 7% 38%	4477
June	1st to 10th	Day	6% 5% 2 6% 4 5% 5% 4 7% 10% 46%	2470
	11th to 20th	Day	5% 4 2 5% 5% 4 4 5% 7% 9% 50%	2470
	21st to end	Day	5% 4 1 3 3 4 5% 3 6% 8% 57%	2470
July	1st to 10th	Day	7% 4 2 5% 4 4 4 4 6% 9% 51%	4120
	11th to 20th	Day	2 3 1 3 4 4 4 4 6% 10% 58%	4120
	21st to end	Day	5% 5% 2 5% 5% 4 5% 4 7% 10% 48%	4465
August	1st to 10th	Day	2 2 1 3 3 3 4 4 6% 8% 65%	4104
	11th to 20th	Day	5% 3 1 4 3 3 4 4 6% 10% 58%	4041
	21st to end	Day	3 2 1 3 4 4 5% 4 8% 10% 55%	4148
September	1st to 10th	Day	10% 5% 1 4 3 3 4 4 5% 7% 54%	2090
	11th to 20th	Day	11% 4 2 6% 4 5% 5% 3 5% 7% 48%	2090
	21st to end	Day	8% 3 2 3 3 3 4 3 5% 6% 59%	2090
October	1st to 10th	Day	7% 3 1 4 4 4 3 3 4 5% 61%	2019
	11th to 20th	Day	11% 5% 2 3 2 2 2 3 4 5% 62%	1900
	21st to end	Day	16% 5% 1 3 3 3 3 2 3 4 58%	2090
November	1st to 10th	Day	13% 5% 2 4 2 3 3 2 4 5% 57%	1898
	11th to 20th	Day	8% 4 2 4 3 3 3 3 4 5% 62%	1761
	21st to end	Day	15% 6% 2 4 3 3 2 2 3 4 55%	1710
December	1st to 10th	Day	14% 7% 2 5% 2 3 3 3 5% 6% 51%	1710
	11th to 20th	Day	16% 9% 2 5% 4 4 4 2 4 5% 46%	2161
	21st to end	Day	19% 6% 2 4 3 3 4 3 5% 6% 47%	3135
January	1st to 10th	Night	13% 7% 2 4 3 3 3 3 4 5% 53%	4108
	11th to 20th	Night	10% 5% 2 4 3 2 2 2 3 5% 63%	4120
	21st to end	Night	20% 7% 2 5% 3 3 2 2 3 4 49%	4532
February	1st to 10th	Night	14% 7% 2 6% 4 3 3 4 3 5% 49%	2420
	11th to 20th	Night	15% 7% 3 4 3 3 3 3 4 5% 49%	2218
	21st to end	Night	16% 6% 2 5% 3 3 3 3 2 5% 52%	1856
March	1st to 10th	Night	15% 7% 2 5% 5% 4 4 3 5% 5% 45%	3419
	11th to 20th	Night	12% 6% 2 5% 3 3 3 3 4 6% 53%	3480
	21st to end	Night	14% 6% 2 5% 4 4 4 3 5% 6% 47%	3817
April	1st to 10th	Night	9% 5% 2 4 4 3 4 3 6% 7% 52%	2090
	11th to 20th	Night	13% 5% 2 5% 4 3 3 3 5% 7% 51%	1937
	21st to end	Night	12% 5% 2 4 3 3 3 3 6% 7% 52%	1753
May	1st to 10th	Night	18% 8% 3 6% 4 4 3 3 4 5% 42%	2823
	11th to 20th	Night	14% 5% 2 5% 3 3 4 3 4 7% 49%	2823
	21st to end	Night	10% 6% 2 6% 3 4 4 4 6% 8% 46%	3090
June	1st to 10th	Night	4 3 1 3 3 3 5% 4 7% 9% 59%	1710
	11th to 20th	Night	3 2 1 4 4 3 3 4 6% 10% 61%	1710
	21st to end	Night	2 2 1 2 4 4 4 3 6% 10% 63%	1710
July	1st to 10th	Night	5% 4 1 4 3 4 4 4 6% 9% 57%	2850
	11th to 20th	Night	3 2 1 3 2 2 2 3 5% 9% 69%	2850
	21st to end	Night	4 3 1 4 3 3 4 4 6% 9% 59%	3098
August	1st to 10th	Night	1 1 1 2 3 3 3 3 5% 7% 72%	2836
	11th to 20th	Night	3 2 1 2 2 2 3 3 5% 10% 67%	2798
	21st to end	Night	3 2 1 4 3 3 4 3 6% 9% 63%	3489
September	1st to 10th	Night	8% 4 1 4 3 3 3 3 5% 7% 59%	2090
	11th to 20th	Night	10% 4 2 5% 4 4 4 3 4 6% 54%	2090
	21st to end	Night	7% 3 1 4 2 2 3 3 4 7% 63%	2090
October	1st to 10th	Night	6% 3 2 4 2 3 3 3 4 6% 64%	2142
	11th to 20th	Night	11% 4 2 3 2 2 3 2 4 5% 64%	2280
	21st to end	Night	15% 5% 1 4 2 2 2 2 2 4 61%	2508
November	1st to 10th	Night	10% 3 2 4 3 3 3 2 4 4 61%	2280
	11th to 20th	Night	9% 5% 2 3 2 3 3 3 5% 6% 60%	2417
	21st to end	Night	15% 6% 2 3 2 3 3 3 4 5% 54%	2470
December	1st to 10th	Night	12% 6% 2 4 3 3 4 3 4 6% 55%	2470
	11th to 20th	Night	12% 6% 2 5% 4 4 3 2 4 5% 51%	3036
	21st to end	Night	16% 7% 2 5% 3 3 2 2 4 5% 51%	4532

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	34% 3 6% 23% 28% 4	2848
	11th to 20th	Day	26% 3 9% 23% 33% 6%	2850
	21st to end	Day	45% 3 3 20% 22% 7%	3135
February	1st to 10th	Day	44% 3 7% 17% 22% 7%	1776
	11th to 20th	Day	40% 4 7% 22% 19% 7%	1859
	21st to end	Day	41% 2 5% 15% 26% 11%	1598
March	1st to 10th	Day	36% 4 7% 15% 27% 12%	3436
	11th to 20th	Day	40% 7% 10% 22% 18% 4	3480
	21st to end	Day	43% 5% 8% 21% 18% 4	3814
April	1st to 10th	Day	36% 5% 8% 23% 19% 10%	2090
	11th to 20th	Day	37% 5% 9% 20% 19% 9%	2192
	21st to end	Day	37% 6% 10% 22% 22% 4	2422
May	1st to 10th	Day	43% 5% 9% 22% 14% 7%	4120
	11th to 20th	Day	37% 6% 10% 27% 20% 1	4086
	21st to end	Day	45% 7% 11% 19% 12% 6%	4489
June	1st to 10th	Day	32% 8% 15% 26% 17% 3	2470
	11th to 20th	Day	28% 7% 13% 28% 21% 4	2470
	21st to end	Day	24% 7% 12% 28% 25% 3	2470
July	1st to 10th	Day	29% 6% 13% 36% 14% 1	4056
	11th to 20th	Day	20% 6% 10% 38% 23% 2	4051
	21st to end	Day	30% 7% 12% 34% 17%	4325
August	1st to 10th	Day	16% 5% 12% 26% 31% 9%	4090
	11th to 20th	Day	22% 5% 14% 39% 18% 2	4080
	21st to end	Day	23% 8% 17% 35% 14% 3	4147
September	1st to 10th	Day	30% 6% 10% 23% 19% 12%	2090
	11th to 20th	Day	35% 6% 10% 19% 21% 8%	2090
	21st to end	Day	24% 6% 7% 22% 30% 11%	2090
October	1st to 10th	Day	16% 3 6% 13% 37% 25%	3357
	11th to 20th	Day	18% 2 5% 20% 34% 21%	3140
	21st to end	Day	25% 3 6% 31% 26% 9%	3428
November	1st to 10th	Day	31% 4 8% 23% 25% 8%	1898
	11th to 20th	Day	25% 4 9% 23% 29% 11%	1761
	21st to end	Day	34% 2 7% 18% 27% 10%	1710
December	1st to 10th	Day	36% 4 7% 25% 23% 5%	1710
	11th to 20th	Day	42% 3 6% 16% 25% 8%	2159
	21st to end	Day	39% 4 6% 23% 23% 6%	3135
January	1st to 10th	Night	32% 4 6% 20% 31% 7%	4108
	11th to 20th	Night	26% 3 9% 22% 31% 8%	4120
	21st to end	Night	41% 3 5% 17% 26% 8%	4532
February	1st to 10th	Night	39% 3 8% 19% 22% 9%	2420
	11th to 20th	Night	37% 4 8% 19% 22% 9%	2218
	21st to end	Night	38% 3 6% 16% 22% 15%	1856
March	1st to 10th	Night	40% 5% 6% 17% 20% 13%	3419
	11th to 20th	Night	34% 4 10% 26% 20% 7%	3480
	21st to end	Night	38% 5% 9% 18% 26% 3	3817
April	1st to 10th	Night	30% 5% 10% 21% 20% 13%	2090
	11th to 20th	Night	34% 6% 9% 19% 20% 13%	1937
	21st to end	Night	31% 4 12% 24% 25% 4	1753
May	1st to 10th	Night	44% 6% 9% 18% 16% 7%	2850
	11th to 20th	Night	34% 6% 12% 24% 21% 2	2824
	21st to end	Night	33% 7% 15% 24% 14% 7%	3099
June	1st to 10th	Night	20% 8% 15% 32% 21% 4	1710
	11th to 20th	Night	18% 7% 13% 31% 24% 7%	1710
	21st to end	Night	17% 7% 13% 31% 26% 6%	1710
July	1st to 10th	Night	23% 6% 15% 38% 15% 3	2805
	11th to 20th	Night	14% 4 9% 43% 27% 3	2796
	21st to end	Night	21% 5% 15% 36% 23% 1	2999
August	1st to 10th	Night	12% 4 8% 32% 38% 6%	2826
	11th to 20th	Night	15% 4 11% 41% 23% 6%	2825
	21st to end	Night	18% 6% 17% 37% 19% 3	3489
September	1st to 10th	Night	26% 5% 9% 22% 27% 11%	2090
	11th to 20th	Night	31% 5% 10% 22% 21% 11%	2090
	21st to end	Night	21% 4 8% 23% 28% 15%	2090
October	1st to 10th	Night	13% 3 6% 13% 35% 30%	3571
	11th to 20th	Night	16% 2 5% 17% 36% 24%	3779
	21st to end	Night	26% 2 4 28% 26% 14%	4120
November	1st to 10th	Night	28% 4 7% 21% 26% 14%	2280
	11th to 20th	Night	25% 4 8% 22% 28% 13%	2417
	21st to end	Night	34% 4 7% 17% 30% 9%	2470
December	1st to 10th	Night	32% 4 8% 24% 22% 11%	2470
	11th to 20th	Night	36% 3 6% 17% 27% 11%	3037
	21st to end	Night	36% 4 6% 20% 25% 10%	4532

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	21% 14% 33% 24% 7%	270
	11th to 20th	Day	20% 16% 39% 19% 5% 2	270
	21st to end	Day	17% 13% 39% 22% 9% 1	297
February	1st to 10th	Day	23% 13% 37% 19% 8%	270
	11th to 20th	Day	21% 17% 41% 18% 3	270
	21st to end	Day	27% 16% 42% 12% 3	225
March	1st to 10th	Day	19% 18% 33% 24% 6% 1	270
	11th to 20th	Day	19% 19% 40% 16% 6% 1	270
	21st to end	Day	18% 12% 44% 19% 5% 1	297
April	1st to 10th	Day	15% 17% 36% 26% 6% 1	270
	11th to 20th	Day	16% 16% 37% 22% 8%	390
	21st to end	Day	15% 13% 39% 23% 8% 2	602
May	1st to 10th	Day	13% 10% 34% 34% 8% 1	653
	11th to 20th	Day	17% 6% 30% 31% 13% 3	675
	21st to end	Day	14% 7% 27% 32% 17% 4	734
June	1st to 10th	Day	6% 3 16% 35% 32% 9%	680
	11th to 20th	Day	6% 3 16% 40% 28% 8%	680
	21st to end	Day	4 1 11% 39% 33% 11%	680
July	1st to 10th	Day	7% 1 7% 33% 37% 14%	671
	11th to 20th	Day	2 1 6% 32% 44% 15%	668
	21st to end	Day	4 1 5% 30% 42% 18%	739
August	1st to 10th	Day	4 1 6% 29% 47% 14%	676
	11th to 20th	Day	7% 1 8% 31% 41% 12%	665
	21st to end	Day	4 4 29% 43% 21%	533
September	1st to 10th	Day	8% 6% 18% 41% 27%	300
	11th to 20th	Day	4 2 9% 22% 46% 17%	300
	21st to end	Day	11% 1 10% 30% 31% 15%	300
October	1st to 10th	Day	3 2 20% 31% 33% 11%	300
	11th to 20th	Day	11% 9% 24% 34% 21% 2	300
	21st to end	Day	24% 9% 25% 22% 17% 2	330
November	1st to 10th	Day	18% 7% 31% 27% 12% 5%	282
	11th to 20th	Day	12% 11% 31% 34% 10% 2	270
	21st to end	Day	19% 13% 36% 23% 8% 1	270
December	1st to 10th	Day	14% 14% 34% 28% 9% 1	270
	11th to 20th	Day	21% 11% 38% 23% 7%	270
	21st to end	Day	21% 13% 36% 24% 6%	297
January	1st to 10th	Night	13% 13% 37% 31% 7%	950
	11th to 20th	Night	16% 15% 36% 27% 5% 1	950
	21st to end	Night	15% 11% 37% 30% 7%	1045
February	1st to 10th	Night	18% 12% 40% 25% 4	900
	11th to 20th	Night	19% 14% 40% 24% 3	744
	21st to end	Night	21% 16% 41% 20% 2	600
March	1st to 10th	Night	16% 14% 38% 27% 5%	570
	11th to 20th	Night	15% 12% 42% 26% 5%	570
	21st to end	Night	14% 13% 40% 27% 5%	627
April	1st to 10th	Night	11% 15% 42% 28% 4	570
	11th to 20th	Night	13% 13% 40% 29% 5%	563
	21st to end	Night	12% 10% 41% 27% 8% 1	570
May	1st to 10th	Night	10% 9% 40% 34% 7% 1	570
	11th to 20th	Night	12% 6% 33% 33% 15% 1	561
	21st to end	Night	8% 4 31% 38% 17% 2	617
June	1st to 10th	Night	5% 2 18% 45% 27% 3	570
	11th to 20th	Night	4 2 21% 53% 20%	570
	21st to end	Night	2 1 17% 48% 28% 5%	570
July	1st to 10th	Night	4 1 10% 42% 38% 5%	555
	11th to 20th	Night	3 10% 44% 39% 4	552
	21st to end	Night	2 7% 43% 42% 5%	624
August	1st to 10th	Night	2 1 6% 49% 39% 4	567
	11th to 20th	Night	6% 1 6% 44% 40% 4	564
	21st to end	Night	3 1 4 45% 38% 8%	627
September	1st to 10th	Night	10% 2 6% 40% 38% 4	570
	11th to 20th	Night	12% 1 10% 38% 35% 3	570
	21st to end	Night	8% 1 15% 42% 31% 3	570
October	1st to 10th	Night	8% 1 23% 39% 27% 3	622
	11th to 20th	Night	13% 5% 29% 37% 15% 1	760
	21st to end	Night	17% 11% 27% 32% 12% 1	836
November	1st to 10th	Night	11% 7% 33% 36% 12% 1	760
	11th to 20th	Night	10% 12% 32% 35% 12%	897
	21st to end	Night	18% 12% 36% 25% 9%	950
December	1st to 10th	Night	14% 12% 35% 33% 6%	950
	11th to 20th	Night	19% 10% 35% 31% 5%	950
	21st to end	Night	17% 12% 39% 25% 6%	1045

Page generated at 2024-11-03 01:11:16. Version ac07

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