Murry State University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Murry State University clear sky chart from 2005-11-06 to 2026-02-01.

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% 7% 2 7% 4 4 4 4 5% 7% 42%	127180
	Night	13% 7% 2 6% 4 4 4 3 5% 7% 44%	124988
Transparency	Day	25% 39% 7% 16% 11% 2	130826
	Night	25% 38% 6% 16% 12% 3	129419
Seeing	Day	16% 8% 23% 25% 19% 9%	17016
	Night	17% 8% 25% 30% 18% 3	26882

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% 10% 4 10% 4 4 4 4 5% 6% 36%	3697
	11th to 20th	Day	14% 9% 3 6% 3 3 3 2 4 5% 48%	3859
	21st to end	Day	20% 8% 3 7% 3 3 4 3 4 6% 40%	4660
February	1st to 10th	Day	21% 10% 3 6% 4 3 4 3 5% 5% 37%	2000
	11th to 20th	Day	20% 10% 3 7% 3 4 3 3 5% 6% 36%	1948
	21st to end	Day	19% 10% 3 6% 4 5% 4 3 4 5% 36%	1650
March	1st to 10th	Day	16% 13% 3 8% 5% 4 3 2 4 5% 38%	4480
	11th to 20th	Day	13% 8% 2 6% 4 3 3 3 4 6% 48%	4698
	21st to end	Day	12% 7% 3 7% 5% 4 4 4 5% 6% 43%	5967
April	1st to 10th	Day	13% 6% 2 7% 5% 4 4 4 5% 7% 44%	2400
	11th to 20th	Day	15% 7% 2 6% 4 4 4 3 5% 6% 42%	2374
	21st to end	Day	16% 8% 2 6% 4 4 4 3 4 8% 40%	2400
May	1st to 10th	Day	18% 9% 3 9% 5% 5% 5% 4 6% 8% 27%	5739
	11th to 20th	Day	16% 8% 3 8% 6% 5% 4 4 6% 8% 32%	5861
	21st to end	Day	14% 7% 3 7% 5% 4 5% 4 6% 8% 38%	6569
June	1st to 10th	Day	10% 5% 2 6% 4 4 5% 5% 7% 7% 45%	2800
	11th to 20th	Day	5% 4 2 5% 4 5% 6% 5% 7% 9% 47%	2800
	21st to end	Day	5% 4 2 5% 4 5% 6% 5% 8% 11% 45%	2800
July	1st to 10th	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 41%	6360
	11th to 20th	Day	6% 5% 2 6% 5% 5% 6% 5% 7% 12% 41%	6360
	21st to end	Day	9% 7% 2 8% 6% 5% 6% 5% 7% 11% 35%	6659
August	1st to 10th	Day	4 3 1 5% 4 4 4 5% 6% 9% 55%	3905
	11th to 20th	Day	8% 5% 2 6% 5% 5% 5% 4 6% 10% 45%	3849
	21st to end	Day	5% 4 1 5% 3 3 4 3 5% 9% 58%	4312
September	1st to 10th	Day	11% 5% 2 5% 4 5% 4 3 5% 8% 48%	2400
	11th to 20th	Day	12% 5% 2 5% 4 4 4 3 5% 6% 49%	2257
	21st to end	Day	12% 6% 2 5% 3 3 3 3 5% 7% 52%	2200
October	1st to 10th	Day	9% 5% 2 4 3 3 3 2 5% 6% 58%	2200
	11th to 20th	Day	12% 6% 2 5% 4 3 3 2 4 5% 55%	2009
	21st to end	Day	19% 7% 2 5% 4 2 3 3 5% 5% 47%	2088
November	1st to 10th	Day	12% 6% 2 5% 3 4 3 3 4 7% 52%	1852
	11th to 20th	Day	14% 8% 2 6% 3 3 3 2 5% 6% 48%	1890
	21st to end	Day	18% 8% 2 6% 3 3 4 3 5% 6% 42%	1890
December	1st to 10th	Day	15% 10% 2 6% 4 4 4 3 4 5% 43%	3020
	11th to 20th	Day	16% 9% 3 7% 4 4 4 4 4 7% 38%	3157
	21st to end	Day	17% 12% 3 9% 6% 5% 5% 4 5% 5% 29%	4070
January	1st to 10th	Night	17% 10% 3 9% 3 3 4 4 5% 6% 37%	6488
	11th to 20th	Night	16% 10% 3 8% 3 3 3 2 3 4 45%	6338
	21st to end	Night	20% 9% 4 6% 3 3 3 3 4 5% 39%	6541
February	1st to 10th	Night	21% 9% 3 7% 6% 3 4 3 4 6% 33%	2401
	11th to 20th	Night	20% 8% 3 8% 4 4 4 3 4 5% 38%	2338
	21st to end	Night	18% 9% 3 7% 5% 4 3 4 4 5% 38%	1980
March	1st to 10th	Night	17% 11% 3 7% 4 3 4 3 4 5% 38%	5373
	11th to 20th	Night	12% 7% 2 5% 3 3 4 4 6% 6% 49%	5292
	21st to end	Night	13% 7% 3 8% 4 4 4 4 5% 7% 41%	4962
April	1st to 10th	Night	12% 6% 3 5% 4 4 3 4 6% 6% 48%	2000
	11th to 20th	Night	15% 7% 3 5% 4 2 3 3 4 7% 48%	1975
	21st to end	Night	15% 6% 2 6% 4 4 5% 3 5% 8% 41%	2000
May	1st to 10th	Night	17% 9% 2 8% 4 4 4 4 6% 7% 34%	4152
	11th to 20th	Night	14% 9% 3 8% 5% 5% 5% 4 6% 7% 34%	4032
	21st to end	Night	14% 6% 2 7% 5% 5% 5% 5% 6% 8% 38%	4274
June	1st to 10th	Night	10% 5% 2 6% 4 5% 4 4 7% 7% 46%	1600
	11th to 20th	Night	5% 4 2 5% 3 3 5% 4 7% 9% 54%	1600
	21st to end	Night	3 2 1 3 3 4 5% 6% 8% 13% 52%	1600
July	1st to 10th	Night	7% 4 2 6% 5% 4 6% 4 6% 9% 46%	3618
	11th to 20th	Night	5% 4 2 6% 4 5% 5% 4 6% 12% 48%	3617
	21st to end	Night	6% 5% 3 8% 5% 5% 5% 5% 8% 14% 37%	4199
August	1st to 10th	Night	3 3 1 5% 3 4 4 3 5% 7% 62%	3244
	11th to 20th	Night	4 4 2 5% 4 4 5% 4 7% 9% 53%	3200
	21st to end	Night	4 3 1 4 3 3 3 3 5% 8% 63%	3586
September	1st to 10th	Night	9% 5% 2 5% 3 4 3 3 5% 6% 56%	2000
	11th to 20th	Night	9% 5% 2 5% 3 3 3 3 5% 8% 53%	2121
	21st to end	Night	10% 5% 2 5% 3 3 4 2 4 6% 54%	2200
October	1st to 10th	Night	8% 4 2 4 3 3 3 3 4 6% 61%	2200
	11th to 20th	Night	13% 4 2 5% 3 3 3 2 4 5% 56%	2388
	21st to end	Night	18% 7% 2 5% 3 2 4 3 4 5% 47%	2750
November	1st to 10th	Night	13% 5% 2 5% 3 2 2 2 5% 5% 55%	2666
	11th to 20th	Night	12% 7% 2 5% 3 3 4 3 4 6% 52%	2730
	21st to end	Night	17% 7% 2 6% 3 3 3 2 4 6% 47%	2730
December	1st to 10th	Night	17% 8% 2 6% 4 3 3 3 4 4 45%	4380
	11th to 20th	Night	18% 8% 3 6% 4 4 3 3 4 5% 42%	5263
	21st to end	Night	19% 11% 4 9% 5% 4 4 3 5% 5% 30%	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	38% 27% 9% 17% 8% 1	3698
	11th to 20th	Day	28% 26% 4 22% 19% 1	3859
	21st to end	Day	34% 29% 5% 13% 13% 6%	4660
February	1st to 10th	Day	19% 62% 5% 9% 4 1	2000
	11th to 20th	Day	22% 61% 4 8% 5% 1	1958
	21st to end	Day	18% 62% 3 8% 7% 3	1650
March	1st to 10th	Day	39% 28% 3 13% 11% 6%	4480
	11th to 20th	Day	24% 30% 4 20% 17% 5%	4698
	21st to end	Day	27% 30% 7% 21% 15%	5969
April	1st to 10th	Day	19% 62% 4 8% 6% 1	2400
	11th to 20th	Day	18% 63% 4 9% 5% 1	2374
	21st to end	Day	17% 62% 4 10% 6% 1	2400
May	1st to 10th	Day	40% 33% 9% 11% 7%	5776
	11th to 20th	Day	37% 33% 9% 15% 6%	5865
	21st to end	Day	33% 31% 6% 15% 13% 2	6583
June	1st to 10th	Day	16% 63% 5% 9% 8% 1	2800
	11th to 20th	Day	13% 63% 6% 10% 7% 1	2800
	21st to end	Day	14% 63% 9% 10% 5%	2800
July	1st to 10th	Day	28% 30% 9% 21% 11% 1	6291
	11th to 20th	Day	25% 31% 12% 27% 4	6285
	21st to end	Day	32% 30% 16% 17% 5%	6467
August	1st to 10th	Day	13% 38% 10% 20% 17% 1	3893
	11th to 20th	Day	22% 38% 9% 17% 13% 1	3885
	21st to end	Day	13% 37% 7% 25% 17% 1	4311
September	1st to 10th	Day	11% 58% 5% 14% 9% 3	2400
	11th to 20th	Day	12% 57% 6% 12% 12% 2	2257
	21st to end	Day	17% 57% 4 13% 9% 1	2200
October	1st to 10th	Day	9% 35% 3 10% 34% 8%	3590
	11th to 20th	Day	11% 36% 4 17% 21% 11%	3249
	21st to end	Day	17% 35% 2 19% 22% 4	3352
November	1st to 10th	Day	21% 53% 3 11% 11% 1	1852
	11th to 20th	Day	17% 54% 3 10% 12% 3	1890
	21st to end	Day	23% 54% 2 12% 8% 1	1890
December	1st to 10th	Day	29% 36% 4 19% 12% 1	3020
	11th to 20th	Day	32% 31% 7% 17% 11% 2	3154
	21st to end	Day	44% 29% 7% 15% 5%	4070
January	1st to 10th	Night	38% 27% 8% 18% 9%	6488
	11th to 20th	Night	32% 26% 4 18% 18% 2	6338
	21st to end	Night	35% 29% 4 16% 11% 4	6541
February	1st to 10th	Night	21% 62% 4 8% 5% 1	2401
	11th to 20th	Night	22% 61% 3 6% 7% 1	2339
	21st to end	Night	17% 62% 3 7% 10% 2	1980
March	1st to 10th	Night	39% 29% 3 10% 13% 6%	5373
	11th to 20th	Night	22% 30% 6% 17% 14% 11%	5292
	21st to end	Night	29% 30% 7% 21% 12% 2	4962
April	1st to 10th	Night	17% 62% 4 10% 7%	2000
	11th to 20th	Night	17% 62% 3 10% 7% 1	1975
	21st to end	Night	15% 63% 4 10% 7% 2	2000
May	1st to 10th	Night	35% 32% 11% 16% 6%	4180
	11th to 20th	Night	37% 32% 10% 14% 7%	4033
	21st to end	Night	33% 32% 8% 18% 9% 1	4282
June	1st to 10th	Night	16% 63% 4 6% 9% 1	1600
	11th to 20th	Night	12% 63% 6% 9% 10% 1	1600
	21st to end	Night	10% 62% 8% 13% 7%	1600
July	1st to 10th	Night	26% 30% 10% 19% 14% 1	3580
	11th to 20th	Night	22% 31% 14% 25% 8% 1	3572
	21st to end	Night	28% 31% 16% 19% 5%	4080
August	1st to 10th	Night	12% 38% 8% 26% 15%	3232
	11th to 20th	Night	16% 39% 12% 22% 10% 1	3230
	21st to end	Night	9% 37% 6% 27% 20% 1	3586
September	1st to 10th	Night	9% 57% 4 16% 11% 2	2000
	11th to 20th	Night	10% 58% 5% 14% 12% 2	2121
	21st to end	Night	13% 58% 4 13% 10% 2	2200
October	1st to 10th	Night	9% 36% 3 9% 34% 10%	3590
	11th to 20th	Night	9% 35% 2 12% 31% 12%	3887
	21st to end	Night	15% 35% 4 17% 20% 8%	4436
November	1st to 10th	Night	19% 53% 4 12% 10% 2	2666
	11th to 20th	Night	15% 54% 2 12% 13% 4	2730
	21st to end	Night	20% 54% 3 14% 8% 1	2730
December	1st to 10th	Night	28% 35% 5% 16% 15% 1	4380
	11th to 20th	Night	29% 31% 5% 18% 15% 1	5265
	21st to end	Night	43% 29% 6% 15% 6% 1	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	26% 19% 35% 16% 4	330
	11th to 20th	Day	24% 21% 38% 14% 2	330
	21st to end	Day	25% 20% 40% 13% 2	363
February	1st to 10th	Day	29% 16% 34% 16% 4 1	300
	11th to 20th	Day	34% 18% 38% 8% 2	300
	21st to end	Day	30% 16% 41% 11% 3	249
March	1st to 10th	Day	26% 14% 39% 18% 3 1	300
	11th to 20th	Day	26% 17% 35% 19% 3	315
	21st to end	Day	23% 17% 34% 18% 7% 1	550
April	1st to 10th	Day	22% 13% 33% 23% 8% 1	500
	11th to 20th	Day	23% 14% 29% 23% 9% 2	492
	21st to end	Day	21% 10% 33% 22% 10% 3	500
May	1st to 10th	Day	21% 12% 27% 28% 8% 3	503
	11th to 20th	Day	19% 7% 23% 27% 17% 7%	527
	21st to end	Day	12% 6% 21% 30% 19% 13%	631
June	1st to 10th	Day	11% 4 17% 28% 23% 17%	730
	11th to 20th	Day	6% 2 16% 32% 33% 11%	730
	21st to end	Day	7% 3 17% 33% 25% 16%	730
July	1st to 10th	Day	9% 2 11% 25% 30% 22%	721
	11th to 20th	Day	8% 1 11% 27% 34% 18%	718
	21st to end	Day	7% 3 13% 25% 33% 19%	734
August	1st to 10th	Day	11% 3 7% 29% 34% 16%	526
	11th to 20th	Day	10% 3 10% 31% 33% 12%	519
	21st to end	Day	11% 1 6% 26% 34% 21%	583
September	1st to 10th	Day	12% 2 10% 28% 32% 17%	530
	11th to 20th	Day	12% 2 9% 25% 34% 18%	530
	21st to end	Day	17% 6% 15% 27% 24% 11%	530
October	1st to 10th	Day	12% 3 17% 34% 27% 7%	530
	11th to 20th	Day	14% 9% 32% 24% 17% 4	339
	21st to end	Day	26% 9% 32% 20% 11% 2	363
November	1st to 10th	Day	16% 10% 37% 23% 12% 2	330
	11th to 20th	Day	16% 13% 36% 25% 8% 1	330
	21st to end	Day	23% 10% 33% 24% 8% 1	330
December	1st to 10th	Day	22% 14% 37% 18% 8%	330
	11th to 20th	Day	22% 17% 33% 22% 6%	330
	21st to end	Day	25% 19% 36% 17% 2	363
January	1st to 10th	Night	25% 13% 33% 25% 4	1050
	11th to 20th	Night	26% 15% 35% 20% 4	1050
	21st to end	Night	22% 13% 39% 24% 2	1115
February	1st to 10th	Night	27% 12% 37% 21% 3	801
	11th to 20th	Night	25% 14% 35% 24% 2	783
	21st to end	Night	25% 14% 38% 22% 1	660
March	1st to 10th	Night	20% 15% 32% 29% 4	800
	11th to 20th	Night	21% 10% 36% 26% 6% 1	758
	21st to end	Night	20% 11% 30% 31% 7%	660
April	1st to 10th	Night	16% 11% 34% 31% 8%	600
	11th to 20th	Night	17% 9% 32% 28% 13% 1	593
	21st to end	Night	18% 6% 32% 32% 11% 1	600
May	1st to 10th	Night	19% 6% 27% 32% 14% 2	600
	11th to 20th	Night	16% 5% 18% 39% 20% 3	591
	21st to end	Night	8% 3 19% 37% 29% 5%	650
June	1st to 10th	Night	12% 3 14% 38% 29% 5%	600
	11th to 20th	Night	6% 2 13% 42% 35% 3	600
	21st to end	Night	3 2 13% 40% 37% 6%	600
July	1st to 10th	Night	8% 2 7% 29% 44% 10%	585
	11th to 20th	Night	7% 2 8% 29% 46% 8%	582
	21st to end	Night	7% 1 8% 33% 42% 9%	657
August	1st to 10th	Night	5% 1 6% 31% 48% 9%	597
	11th to 20th	Night	8% 2 6% 40% 39% 6%	594
	21st to end	Night	7% 2 5% 30% 46% 9%	660
September	1st to 10th	Night	11% 2 10% 33% 39% 6%	600
	11th to 20th	Night	11% 2 7% 31% 41% 8%	721
	21st to end	Night	12% 3 17% 34% 30% 5%	800
October	1st to 10th	Night	10% 3 16% 37% 29% 5%	800
	11th to 20th	Night	15% 5% 25% 34% 18% 3	800
	21st to end	Night	22% 6% 29% 30% 13% 1	880
November	1st to 10th	Night	14% 8% 27% 36% 14% 1	820
	11th to 20th	Night	14% 10% 33% 33% 10%	840
	21st to end	Night	22% 10% 27% 29% 11% 1	840
December	1st to 10th	Night	25% 10% 30% 28% 6%	840
	11th to 20th	Night	23% 9% 33% 28% 6%	1000
	21st to end	Night	28% 11% 31% 26% 4	1155

Page generated at 2026-01-29 00:21:42. Version ac07

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