Muscatine
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Muscatine clear sky chart from 2005-11-06 to 2026-01-17.

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	13% 8% 3 7% 5% 4 4 4 5% 7% 39%	127750
	Night	13% 9% 3 8% 5% 4 4 3 5% 6% 40%	124206
Transparency	Day	28% 38% 8% 16% 10% 1	131301
	Night	29% 37% 7% 15% 10% 1	128730
Seeing	Day	16% 10% 28% 27% 15% 5%	17425
	Night	17% 9% 31% 31% 12% 1	27348

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	9% 12% 5% 16% 8% 6% 5% 4 5% 5% 25%	3697
	11th to 20th	Day	8% 9% 4 13% 8% 6% 6% 5% 7% 5% 30%	3758
	21st to end	Day	13% 16% 7% 10% 5% 4 3 3 4 5% 29%	4488
February	1st to 10th	Day	14% 13% 5% 9% 6% 5% 5% 4 5% 7% 29%	1800
	11th to 20th	Day	14% 10% 4 8% 5% 6% 4 3 4 7% 35%	1827
	21st to end	Day	13% 11% 3 10% 6% 4 3 3 5% 6% 36%	1650
March	1st to 10th	Day	18% 10% 3 6% 3 2 3 2 3 5% 46%	4604
	11th to 20th	Day	8% 6% 3 6% 4 4 5% 4 5% 7% 48%	4980
	21st to end	Day	20% 10% 4 10% 5% 4 4 3 5% 6% 27%	5723
April	1st to 10th	Day	17% 12% 4 8% 5% 4 3 4 4 6% 34%	2400
	11th to 20th	Day	17% 9% 4 7% 5% 4 4 3 5% 6% 37%	2374
	21st to end	Day	20% 8% 3 6% 5% 5% 4 3 5% 6% 35%	2400
May	1st to 10th	Day	14% 7% 3 7% 5% 5% 5% 4 5% 8% 37%	6000
	11th to 20th	Day	15% 6% 2 6% 4 4 4 3 5% 7% 44%	6319
	21st to end	Day	14% 7% 3 7% 5% 5% 4 4 6% 8% 38%	6935
June	1st to 10th	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 44%	2800
	11th to 20th	Day	9% 5% 2 6% 4 5% 4 4 5% 8% 46%	2800
	21st to end	Day	10% 6% 2 6% 4 5% 5% 4 7% 8% 43%	2800
July	1st to 10th	Day	8% 7% 3 7% 4 5% 5% 5% 7% 9% 40%	6360
	11th to 20th	Day	9% 6% 2 6% 4 5% 5% 4 6% 9% 44%	6360
	21st to end	Day	11% 6% 2 6% 5% 5% 5% 5% 6% 10% 38%	6817
August	1st to 10th	Day	7% 4 2 6% 4 5% 5% 4 8% 10% 44%	4234
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 7% 10% 42%	4016
	21st to end	Day	7% 5% 2 6% 4 4 4 4 6% 9% 50%	4312
September	1st to 10th	Day	12% 4 1 5% 4 4 4 4 5% 8% 50%	2400
	11th to 20th	Day	9% 4 2 4 4 3 4 4 6% 7% 53%	2400
	21st to end	Day	10% 5% 3 6% 3 4 4 4 5% 8% 48%	2136
October	1st to 10th	Day	12% 6% 3 5% 3 3 3 3 4 6% 51%	2000
	11th to 20th	Day	15% 8% 3 7% 4 3 3 3 4 6% 43%	2000
	21st to end	Day	19% 8% 2 6% 4 3 3 3 5% 5% 42%	2142
November	1st to 10th	Day	11% 9% 3 6% 4 4 4 4 5% 6% 45%	1852
	11th to 20th	Day	15% 11% 3 7% 4 4 4 3 5% 8% 36%	1838
	21st to end	Day	16% 12% 3 8% 3 4 4 3 4 6% 37%	1680
December	1st to 10th	Day	9% 10% 3 8% 4 3 3 3 5% 6% 46%	2690
	11th to 20th	Day	14% 12% 5% 14% 5% 5% 4 3 6% 6% 25%	3088
	21st to end	Day	23% 22% 7% 11% 4 4 3 3 4 4 16%	4070
January	1st to 10th	Night	12% 12% 7% 14% 5% 4 4 3 4 4 32%	6488
	11th to 20th	Night	11% 13% 6% 11% 8% 6% 5% 4 6% 5% 26%	6353
	21st to end	Night	15% 13% 5% 11% 5% 4 4 3 4 6% 31%	6490
February	1st to 10th	Night	15% 12% 4 7% 7% 4 3 4 5% 7% 33%	2600
	11th to 20th	Night	13% 10% 3 8% 5% 4 4 3 5% 6% 39%	2458
	21st to end	Night	15% 11% 3 7% 5% 4 3 3 4 4 42%	1980
March	1st to 10th	Night	17% 9% 3 6% 4 3 3 3 4 5% 43%	5291
	11th to 20th	Night	11% 6% 2 6% 4 4 4 3 4 7% 50%	4980
	21st to end	Night	19% 12% 5% 9% 5% 5% 4 4 5% 5% 27%	5204
April	1st to 10th	Night	16% 10% 3 6% 4 3 3 3 5% 6% 42%	2000
	11th to 20th	Night	16% 8% 3 6% 4 4 4 3 4 5% 42%	1975
	21st to end	Night	17% 7% 3 7% 4 4 4 4 6% 7% 38%	2000
May	1st to 10th	Night	19% 7% 3 6% 5% 4 4 3 4 6% 40%	3891
	11th to 20th	Night	11% 5% 2 6% 5% 5% 5% 4 6% 7% 45%	3596
	21st to end	Night	14% 7% 3 6% 4 4 4 4 6% 7% 43%	3942
June	1st to 10th	Night	8% 5% 2 6% 4 3 5% 3 7% 8% 50%	1600
	11th to 20th	Night	8% 4 2 6% 5% 4 5% 5% 6% 10% 45%	1600
	21st to end	Night	10% 5% 2 6% 4 5% 3 4 6% 8% 48%	1600
July	1st to 10th	Night	12% 5% 2 7% 4 4 4 4 8% 9% 42%	3618
	11th to 20th	Night	8% 5% 1 5% 4 3 4 3 5% 8% 53%	3617
	21st to end	Night	10% 6% 2 6% 4 5% 4 4 6% 8% 43%	4050
August	1st to 10th	Night	5% 4 1 5% 4 4 4 4 6% 9% 55%	2926
	11th to 20th	Night	7% 4 2 5% 4 4 4 3 5% 8% 55%	3037
	21st to end	Night	7% 3 2 5% 4 4 4 4 5% 8% 55%	3586
September	1st to 10th	Night	10% 4 1 5% 3 3 3 3 4 6% 57%	2000
	11th to 20th	Night	10% 5% 2 5% 3 4 4 3 6% 7% 51%	2000
	21st to end	Night	7% 5% 2 5% 3 4 5% 3 5% 8% 53%	2237
October	1st to 10th	Night	11% 5% 3 5% 3 3 3 2 5% 5% 55%	2400
	11th to 20th	Night	14% 7% 2 5% 4 4 3 2 5% 6% 48%	2400
	21st to end	Night	18% 8% 3 7% 4 4 3 3 5% 5% 41%	2695
November	1st to 10th	Night	12% 7% 2 4 3 3 3 3 5% 6% 53%	2666
	11th to 20th	Night	14% 9% 3 7% 5% 3 4 3 5% 6% 40%	2777
	21st to end	Night	17% 11% 3 8% 3 3 4 3 5% 6% 38%	2940
December	1st to 10th	Night	8% 10% 3 7% 4 4 4 4 4 6% 46%	4720
	11th to 20th	Night	15% 12% 5% 10% 5% 4 4 3 5% 6% 32%	5339
	21st to end	Night	24% 19% 7% 11% 5% 4 4 3 4 4 16%	7150

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	49% 26% 6% 15% 4	3698
	11th to 20th	Day	39% 26% 7% 12% 14% 3	3758
	21st to end	Day	43% 27% 9% 15% 6%	4488
February	1st to 10th	Day	22% 62% 5% 7% 5%	1800
	11th to 20th	Day	20% 61% 4 9% 5% 1	1836
	21st to end	Day	18% 61% 4 10% 5% 2	1650
March	1st to 10th	Day	31% 28% 5% 20% 14% 3	4604
	11th to 20th	Day	23% 28% 6% 27% 14% 1	4980
	21st to end	Day	42% 29% 11% 13% 4	5725
April	1st to 10th	Day	22% 62% 4 8% 3	2400
	11th to 20th	Day	19% 62% 5% 9% 4 1	2374
	21st to end	Day	19% 62% 4 8% 6% 1	2400
May	1st to 10th	Day	32% 29% 7% 16% 15% 1	6036
	11th to 20th	Day	29% 29% 8% 22% 9% 3	6323
	21st to end	Day	32% 29% 8% 19% 11% 1	6949
June	1st to 10th	Day	10% 63% 6% 11% 8% 1	2800
	11th to 20th	Day	15% 63% 6% 9% 7% 1	2800
	21st to end	Day	15% 62% 7% 11% 5% 1	2800
July	1st to 10th	Day	32% 28% 9% 21% 10% 1	6291
	11th to 20th	Day	30% 27% 10% 22% 11%	6285
	21st to end	Day	32% 28% 14% 15% 10% 1	6623
August	1st to 10th	Day	21% 37% 14% 21% 8%	4220
	11th to 20th	Day	26% 37% 11% 18% 8%	4055
	21st to end	Day	22% 38% 9% 20% 9% 1	4311
September	1st to 10th	Day	14% 57% 4 12% 11% 1	2400
	11th to 20th	Day	11% 58% 6% 15% 7% 3	2400
	21st to end	Day	16% 57% 5% 12% 8% 1	2136
October	1st to 10th	Day	13% 35% 2 18% 30% 1	3260
	11th to 20th	Day	13% 35% 7% 14% 26% 4	3240
	21st to end	Day	25% 36% 5% 20% 12% 2	3444
November	1st to 10th	Day	21% 54% 7% 11% 7% 1	1852
	11th to 20th	Day	20% 54% 5% 12% 8% 1	1838
	21st to end	Day	26% 55% 6% 10% 3	1680
December	1st to 10th	Day	23% 34% 10% 27% 6% 1	2690
	11th to 20th	Day	44% 31% 7% 11% 6% 2	3085
	21st to end	Day	60% 26% 6% 6% 2	4070
January	1st to 10th	Night	45% 25% 8% 16% 6%	6488
	11th to 20th	Night	45% 26% 9% 8% 12% 1	6353
	21st to end	Night	41% 28% 6% 14% 10% 1	6490
February	1st to 10th	Night	19% 62% 5% 8% 5%	2600
	11th to 20th	Night	19% 60% 4 9% 7%	2459
	21st to end	Night	16% 61% 3 10% 9% 2	1980
March	1st to 10th	Night	34% 28% 4 18% 14% 2	5291
	11th to 20th	Night	23% 28% 5% 25% 15% 3	4980
	21st to end	Night	43% 30% 9% 12% 6% 1	5204
April	1st to 10th	Night	19% 62% 3 11% 4 1	2000
	11th to 20th	Night	17% 63% 4 10% 5% 1	1975
	21st to end	Night	18% 62% 4 8% 7% 2	2000
May	1st to 10th	Night	35% 29% 6% 13% 15% 2	3919
	11th to 20th	Night	27% 30% 11% 18% 12% 2	3597
	21st to end	Night	31% 28% 6% 22% 12% 1	3950
June	1st to 10th	Night	10% 63% 7% 11% 8% 2	1600
	11th to 20th	Night	13% 63% 5% 12% 7% 1	1600
	21st to end	Night	14% 61% 6% 10% 8% 1	1600
July	1st to 10th	Night	31% 28% 10% 20% 11% 1	3580
	11th to 20th	Night	23% 27% 11% 23% 15%	3572
	21st to end	Night	30% 28% 13% 16% 10% 1	3933
August	1st to 10th	Night	17% 38% 12% 21% 12%	2916
	11th to 20th	Night	19% 37% 13% 22% 9% 1	3064
	21st to end	Night	20% 38% 9% 22% 10% 1	3586
September	1st to 10th	Night	12% 57% 5% 13% 12% 1	2000
	11th to 20th	Night	12% 57% 5% 13% 9% 3	2000
	21st to end	Night	15% 57% 5% 11% 11% 1	2237
October	1st to 10th	Night	16% 35% 2 17% 28% 2	3920
	11th to 20th	Night	14% 35% 6% 15% 27% 4	3899
	21st to end	Night	29% 35% 4 14% 14% 3	4343
November	1st to 10th	Night	18% 53% 6% 12% 8% 2	2666
	11th to 20th	Night	21% 54% 4 12% 9% 1	2777
	21st to end	Night	25% 54% 4 11% 5% 1	2940
December	1st to 10th	Night	23% 35% 8% 25% 9%	4720
	11th to 20th	Night	38% 31% 8% 17% 6% 1	5341
	21st to end	Night	58% 26% 6% 7% 3	7150

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	20% 13% 37% 22% 7% 1	330
	11th to 20th	Day	19% 20% 42% 14% 4 1	318
	21st to end	Day	20% 17% 36% 20% 5% 1	330
February	1st to 10th	Day	24% 15% 41% 16% 5%	300
	11th to 20th	Day	22% 18% 36% 18% 5% 1	300
	21st to end	Day	22% 15% 46% 14% 2	249
March	1st to 10th	Day	19% 18% 41% 19% 4	300
	11th to 20th	Day	20% 22% 32% 18% 6% 2	300
	21st to end	Day	28% 17% 34% 16% 4 1	436
April	1st to 10th	Day	24% 15% 35% 19% 7%	500
	11th to 20th	Day	24% 16% 27% 21% 11% 1	492
	21st to end	Day	23% 11% 35% 20% 8% 2	500
May	1st to 10th	Day	17% 10% 38% 24% 8% 3	643
	11th to 20th	Day	20% 12% 27% 25% 14% 3	725
	21st to end	Day	17% 7% 28% 28% 14% 6%	789
June	1st to 10th	Day	8% 6% 25% 32% 21% 7%	730
	11th to 20th	Day	9% 5% 28% 33% 21% 4	730
	21st to end	Day	11% 7% 30% 32% 17% 3	730
July	1st to 10th	Day	9% 4 17% 32% 23% 14%	721
	11th to 20th	Day	10% 4 20% 37% 22% 8%	718
	21st to end	Day	7% 3 19% 38% 27% 6%	794
August	1st to 10th	Day	7% 2 21% 36% 25% 9%	726
	11th to 20th	Day	10% 4 16% 33% 25% 11%	625
	21st to end	Day	8% 3 17% 34% 28% 10%	583
September	1st to 10th	Day	12% 5% 18% 34% 23% 8%	530
	11th to 20th	Day	7% 3 19% 35% 26% 11%	530
	21st to end	Day	12% 7% 24% 27% 20% 10%	460
October	1st to 10th	Day	17% 7% 24% 28% 18% 6%	330
	11th to 20th	Day	17% 19% 32% 22% 9% 1	330
	21st to end	Day	31% 12% 31% 21% 5% 1	363
November	1st to 10th	Day	16% 10% 43% 20% 8% 3	330
	11th to 20th	Day	22% 16% 32% 20% 7% 2	330
	21st to end	Day	25% 10% 36% 23% 6%	330
December	1st to 10th	Day	14% 16% 42% 21% 5% 2	330
	11th to 20th	Day	18% 17% 35% 22% 8%	330
	21st to end	Day	27% 19% 34% 17% 2	363
January	1st to 10th	Night	17% 11% 39% 26% 6% 1	1050
	11th to 20th	Night	19% 13% 38% 26% 5%	1031
	21st to end	Night	19% 12% 36% 28% 5%	1100
February	1st to 10th	Night	22% 11% 38% 25% 4	1000
	11th to 20th	Night	18% 14% 37% 28% 3	904
	21st to end	Night	21% 14% 40% 22% 3 1	660
March	1st to 10th	Night	20% 11% 40% 24% 4 1	770
	11th to 20th	Night	18% 11% 35% 30% 7%	600
	21st to end	Night	25% 11% 35% 24% 4 1	660
April	1st to 10th	Night	22% 14% 37% 24% 3	600
	11th to 20th	Night	20% 14% 29% 30% 6% 1	593
	21st to end	Night	21% 8% 33% 31% 8%	600
May	1st to 10th	Night	19% 7% 36% 30% 8% 1	600
	11th to 20th	Night	18% 5% 30% 36% 10% 1	591
	21st to end	Night	12% 4 28% 36% 18% 1	650
June	1st to 10th	Night	11% 3 23% 47% 15% 1	600
	11th to 20th	Night	9% 3 27% 42% 18%	600
	21st to end	Night	12% 4 26% 41% 18% 1	600
July	1st to 10th	Night	8% 2 12% 43% 31% 4	585
	11th to 20th	Night	6% 2 17% 45% 27% 3	582
	21st to end	Night	8% 2 16% 42% 31% 2	657
August	1st to 10th	Night	6% 2 14% 44% 31% 2	597
	11th to 20th	Night	8% 2 12% 45% 28% 5%	594
	21st to end	Night	8% 1 14% 46% 28% 3	660
September	1st to 10th	Night	11% 3 17% 39% 26% 4	600
	11th to 20th	Night	11% 3 19% 36% 26% 5%	600
	21st to end	Night	9% 6% 24% 34% 24% 2	772
October	1st to 10th	Night	13% 6% 28% 33% 19% 2	800
	11th to 20th	Night	19% 10% 30% 31% 10%	800
	21st to end	Night	22% 10% 34% 26% 7%	880
November	1st to 10th	Night	16% 8% 37% 30% 8%	820
	11th to 20th	Night	20% 12% 37% 25% 6%	887
	21st to end	Night	22% 12% 35% 25% 6%	1050
December	1st to 10th	Night	19% 11% 39% 25% 6%	1050
	11th to 20th	Night	22% 12% 33% 27% 6%	1050
	21st to end	Night	28% 13% 32% 24% 3	1155

Page generated at 2026-01-14 00:14:26. Version ac07

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