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 2024-07-03.

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 6% 4 4 4 4 6% 7% 42%	89411
	Night	14% 7% 2 6% 4 4 4 3 5% 7% 44%	89754
Transparency	Day	20% 55% 5% 11% 8% 1	89170
	Night	20% 53% 5% 12% 8% 2	89602
Seeing	Day	16% 8% 23% 25% 19% 9%	14891
	Night	17% 7% 25% 30% 18% 3	24726

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	13% 13% 3 9% 5% 5% 4 4 4 5% 36%	2527
	11th to 20th	Day	18% 10% 3 6% 4 3 4 3 4 5% 42%	2630
	21st to end	Day	24% 11% 3 8% 4 3 4 3 4 5% 32%	3180
February	1st to 10th	Day	20% 10% 3 6% 4 4 4 3 6% 5% 37%	1900
	11th to 20th	Day	19% 10% 3 7% 3 4 4 4 5% 6% 37%	1848
	21st to end	Day	20% 10% 3 6% 4 4 5% 3 4 5% 34%	1570
March	1st to 10th	Day	20% 13% 3 8% 4 3 3 2 4 5% 34%	3120
	11th to 20th	Day	14% 8% 2 6% 3 3 3 3 4 6% 47%	3282
	21st to end	Day	12% 7% 3 7% 5% 4 4 4 5% 7% 42%	4165
April	1st to 10th	Day	12% 6% 2 7% 5% 4 4 4 5% 7% 44%	2280
	11th to 20th	Day	16% 7% 2 7% 4 4 4 3 4 6% 42%	2254
	21st to end	Day	16% 7% 2 6% 4 4 4 3 4 8% 41%	2280
May	1st to 10th	Day	17% 7% 2 7% 5% 5% 4 4 6% 9% 33%	4001
	11th to 20th	Day	16% 7% 2 6% 5% 4 4 3 5% 8% 38%	4081
	21st to end	Day	10% 7% 3 7% 5% 5% 5% 4 7% 8% 39%	4570
June	1st to 10th	Day	10% 5% 2 6% 4 4 5% 5% 7% 7% 45%	2660
	11th to 20th	Day	4 4 2 4 4 5% 6% 5% 7% 9% 49%	2660
	21st to end	Day	5% 4 2 5% 4 5% 6% 5% 8% 11% 44%	2660
July	1st to 10th	Day	8% 5% 2 7% 6% 6% 6% 5% 8% 9% 37%	2549
	11th to 20th	Day	7% 5% 2 5% 5% 5% 5% 6% 7% 10% 43%	2520
	21st to end	Day	6% 5% 2 6% 6% 5% 7% 5% 7% 11% 41%	2640
August	1st to 10th	Day	7% 5% 2 6% 5% 5% 5% 6% 7% 10% 43%	2148
	11th to 20th	Day	10% 5% 2 7% 5% 5% 5% 4 6% 8% 43%	2125
	21st to end	Day	9% 5% 2 6% 3 4 5% 4 6% 11% 47%	2376
September	1st to 10th	Day	12% 5% 2 5% 4 4 4 3 6% 8% 47%	2160
	11th to 20th	Day	13% 5% 2 5% 5% 4 4 4 5% 6% 49%	2032
	21st to end	Day	11% 5% 2 4 4 3 3 3 5% 7% 54%	1980
October	1st to 10th	Day	9% 5% 2 4 4 3 3 2 5% 6% 56%	1980
	11th to 20th	Day	13% 6% 2 6% 4 3 3 2 4 5% 52%	1809
	21st to end	Day	19% 7% 2 5% 4 2 3 3 5% 5% 46%	1880
November	1st to 10th	Day	11% 5% 2 5% 3 4 3 3 4 6% 55%	1672
	11th to 20th	Day	14% 8% 2 5% 3 3 3 2 5% 6% 49%	1710
	21st to end	Day	18% 8% 2 6% 3 3 4 3 5% 5% 42%	1710
December	1st to 10th	Day	18% 10% 3 5% 5% 4 5% 4 4 5% 38%	1710
	11th to 20th	Day	15% 10% 3 7% 5% 4 4 4 5% 6% 37%	1959
	21st to end	Day	16% 12% 3 9% 5% 5% 5% 3 5% 5% 32%	2783
January	1st to 10th	Night	19% 9% 3 5% 3 3 4 4 5% 6% 39%	4428
	11th to 20th	Night	16% 11% 3 8% 4 4 3 3 4 4 39%	4338
	21st to end	Night	24% 10% 4 6% 3 3 3 3 4 6% 34%	4470
February	1st to 10th	Night	21% 10% 3 7% 6% 3 4 3 4 6% 33%	2280
	11th to 20th	Night	18% 7% 3 8% 4 4 4 3 4 5% 39%	2218
	21st to end	Night	19% 9% 3 7% 5% 4 3 4 4 5% 37%	1884
March	1st to 10th	Night	22% 11% 3 7% 4 3 3 3 3 4 37%	3733
	11th to 20th	Night	13% 7% 3 6% 4 3 4 3 4 5% 48%	3694
	21st to end	Night	14% 8% 3 8% 4 4 4 3 5% 6% 41%	3466
April	1st to 10th	Night	11% 5% 3 5% 3 4 3 4 6% 6% 49%	1900
	11th to 20th	Night	15% 7% 2 5% 4 2 3 3 4 7% 47%	1875
	21st to end	Night	15% 6% 2 6% 4 4 5% 3 5% 8% 42%	1900
May	1st to 10th	Night	17% 7% 2 7% 4 4 3 3 5% 7% 40%	2890
	11th to 20th	Night	12% 7% 2 6% 4 4 4 4 6% 8% 43%	2812
	21st to end	Night	8% 5% 2 6% 5% 5% 5% 5% 8% 10% 42%	2971
June	1st to 10th	Night	10% 5% 2 6% 4 5% 4 4 7% 7% 46%	1520
	11th to 20th	Night	5% 4 2 5% 2 3 5% 4 7% 9% 55%	1520
	21st to end	Night	3 2 1 3 3 4 5% 6% 8% 13% 52%	1520
July	1st to 10th	Night	6% 4 2 6% 6% 3 5% 4 7% 10% 47%	1456
	11th to 20th	Night	6% 4 2 4 3 5% 4 4 6% 10% 52%	1440
	21st to end	Night	6% 3 2 5% 4 4 5% 4 7% 11% 49%	1670
August	1st to 10th	Night	4 3 2 7% 4 5% 5% 4 7% 9% 50%	1790
	11th to 20th	Night	6% 4 1 5% 4 4 5% 4 6% 9% 52%	1776
	21st to end	Night	7% 4 1 5% 4 3 4 4 7% 9% 52%	1980
September	1st to 10th	Night	9% 5% 2 5% 3 3 3 3 5% 6% 55%	1800
	11th to 20th	Night	9% 5% 1 5% 4 3 3 3 5% 8% 54%	1908
	21st to end	Night	8% 5% 2 5% 3 3 4 2 4 7% 56%	1980
October	1st to 10th	Night	8% 5% 2 4 3 3 3 3 4 6% 59%	1980
	11th to 20th	Night	15% 5% 2 5% 3 3 3 3 4 5% 53%	2148
	21st to end	Night	19% 7% 2 5% 3 3 4 3 4 5% 47%	2474
November	1st to 10th	Night	12% 4 2 5% 3 2 2 2 5% 5% 57%	2406
	11th to 20th	Night	12% 6% 2 5% 3 3 4 3 5% 6% 51%	2470
	21st to end	Night	17% 7% 2 5% 3 3 3 3 4 6% 47%	2470
December	1st to 10th	Night	18% 10% 2 6% 4 4 4 3 5% 5% 38%	2470
	11th to 20th	Night	16% 8% 3 5% 4 4 4 3 4 5% 44%	3233
	21st to end	Night	16% 11% 3 9% 5% 5% 5% 3 5% 6% 31%	4884

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	33% 38% 4 17% 7% 1	2528
	11th to 20th	Day	30% 38% 5% 16% 11% 1	2630
	21st to end	Day	36% 42% 5% 11% 6% 1	3180
February	1st to 10th	Day	17% 65% 4 9% 4 1	1900
	11th to 20th	Day	19% 64% 3 9% 4 1	1858
	21st to end	Day	18% 65% 3 6% 5% 3	1570
March	1st to 10th	Day	38% 40% 3 8% 5% 6%	3120
	11th to 20th	Day	18% 41% 4 20% 13% 4	3282
	21st to end	Day	21% 41% 7% 16% 14% 1	4165
April	1st to 10th	Day	17% 65% 4 8% 5% 1	2280
	11th to 20th	Day	17% 66% 3 8% 5% 1	2254
	21st to end	Day	15% 65% 4 10% 6% 1	2280
May	1st to 10th	Day	28% 44% 9% 12% 8%	4038
	11th to 20th	Day	27% 42% 6% 17% 7%	4085
	21st to end	Day	25% 42% 6% 10% 16%	4583
June	1st to 10th	Day	14% 66% 5% 7% 7% 1	2660
	11th to 20th	Day	11% 66% 6% 10% 7% 1	2660
	21st to end	Day	13% 66% 8% 9% 4	2660
July	1st to 10th	Day	17% 64% 6% 8% 4 1	2480
	11th to 20th	Day	12% 63% 7% 13% 5% 1	2445
	21st to end	Day	12% 63% 6% 13% 6% 1	2493
August	1st to 10th	Day	15% 66% 7% 8% 4	2136
	11th to 20th	Day	15% 65% 5% 9% 6%	2125
	21st to end	Day	12% 64% 8% 9% 6% 1	2376
September	1st to 10th	Day	9% 64% 5% 14% 7% 1	2160
	11th to 20th	Day	11% 63% 5% 10% 9% 2	2032
	21st to end	Day	12% 63% 4 14% 7% 1	1980
October	1st to 10th	Day	13% 63% 5% 12% 6% 1	1980
	11th to 20th	Day	13% 62% 3 9% 10% 3	1809
	21st to end	Day	17% 62% 2 10% 7% 2	1880
November	1st to 10th	Day	17% 58% 3 9% 10% 1	1672
	11th to 20th	Day	14% 59% 3 9% 11% 3	1710
	21st to end	Day	20% 59% 2 11% 7% 1	1710
December	1st to 10th	Day	21% 60% 3 8% 6% 1	1710
	11th to 20th	Day	22% 49% 5% 15% 8% 1	1956
	21st to end	Day	36% 40% 6% 11% 7%	2783
January	1st to 10th	Night	29% 38% 5% 20% 8% 1	4428
	11th to 20th	Night	31% 37% 5% 15% 9% 2	4338
	21st to end	Night	34% 41% 4 13% 7% 1	4470
February	1st to 10th	Night	19% 65% 3 8% 5% 1	2280
	11th to 20th	Night	19% 64% 2 6% 7% 1	2219
	21st to end	Night	17% 64% 3 5% 8% 2	1884
March	1st to 10th	Night	36% 41% 3 6% 9% 4	3733
	11th to 20th	Night	19% 41% 6% 15% 11% 7%	3694
	21st to end	Night	23% 41% 6% 17% 13%	3466
April	1st to 10th	Night	14% 65% 3 10% 7%	1900
	11th to 20th	Night	16% 66% 3 8% 6% 1	1875
	21st to end	Night	14% 65% 3 9% 7% 2	1900
May	1st to 10th	Night	24% 43% 10% 15% 7%	2918
	11th to 20th	Night	24% 42% 9% 16% 9%	2813
	21st to end	Night	22% 44% 9% 16% 8%	2979
June	1st to 10th	Night	15% 66% 4 5% 8% 1	1520
	11th to 20th	Night	10% 65% 6% 9% 9% 1	1520
	21st to end	Night	9% 65% 8% 12% 6%	1520
July	1st to 10th	Night	13% 65% 6% 10% 5% 1	1416
	11th to 20th	Night	9% 63% 6% 14% 7% 1	1392
	21st to end	Night	10% 62% 6% 15% 8%	1578
August	1st to 10th	Night	12% 66% 7% 9% 5%	1778
	11th to 20th	Night	11% 66% 7% 10% 6%	1776
	21st to end	Night	10% 64% 7% 11% 6% 1	1980
September	1st to 10th	Night	8% 63% 4 16% 8% 1	1800
	11th to 20th	Night	7% 64% 5% 12% 10% 1	1908
	21st to end	Night	9% 63% 4 14% 9% 1	1980
October	1st to 10th	Night	11% 63% 4 13% 9% 1	1980
	11th to 20th	Night	14% 62% 2 8% 11% 3	2148
	21st to end	Night	17% 62% 2 9% 8% 2	2474
November	1st to 10th	Night	17% 58% 2 11% 10% 2	2406
	11th to 20th	Night	13% 59% 2 9% 12% 4	2470
	21st to end	Night	17% 60% 3 11% 9%	2470
December	1st to 10th	Night	22% 60% 4 7% 5% 2	2470
	11th to 20th	Night	18% 49% 4 15% 13% 2	3235
	21st to end	Night	34% 40% 5% 11% 7% 2	4884

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	27% 17% 35% 16% 4	270
	11th to 20th	Day	28% 16% 38% 15% 3	270
	21st to end	Day	24% 19% 39% 15% 3	297
February	1st to 10th	Day	29% 13% 35% 17% 4 1	270
	11th to 20th	Day	33% 16% 39% 9% 3	270
	21st to end	Day	32% 16% 37% 11% 4	225
March	1st to 10th	Day	27% 12% 39% 19% 3 1	270
	11th to 20th	Day	25% 17% 35% 20% 3	284
	21st to end	Day	24% 16% 33% 19% 8% 1	506
April	1st to 10th	Day	21% 14% 33% 23% 9% 1	460
	11th to 20th	Day	23% 12% 30% 23% 9% 2	452
	21st to end	Day	22% 9% 33% 22% 10% 3	460
May	1st to 10th	Day	20% 11% 28% 28% 9% 4	463
	11th to 20th	Day	19% 5% 22% 29% 17% 8%	487
	21st to end	Day	11% 4 20% 31% 20% 14%	584
June	1st to 10th	Day	11% 4 17% 27% 23% 17%	680
	11th to 20th	Day	4 2 16% 34% 33% 12%	680
	21st to end	Day	7% 3 18% 34% 24% 15%	680
July	1st to 10th	Day	9% 2 10% 24% 31% 24%	632
	11th to 20th	Day	9% 1 11% 25% 35% 19%	618
	21st to end	Day	7% 2 12% 26% 33% 20%	630
August	1st to 10th	Day	12% 3 5% 29% 34% 17%	446
	11th to 20th	Day	12% 3 8% 31% 35% 11%	439
	21st to end	Day	13% 1 5% 24% 36% 20%	495
September	1st to 10th	Day	11% 2 8% 27% 32% 20%	450
	11th to 20th	Day	12% 1 9% 25% 34% 19%	450
	21st to end	Day	15% 5% 14% 27% 26% 13%	450
October	1st to 10th	Day	12% 4 18% 34% 26% 7%	450
	11th to 20th	Day	16% 10% 33% 24% 14% 4	279
	21st to end	Day	28% 11% 25% 21% 13% 2	297
November	1st to 10th	Day	14% 7% 37% 24% 15% 3	270
	11th to 20th	Day	17% 11% 35% 26% 10% 1	270
	21st to end	Day	25% 9% 29% 27% 9% 1	270
December	1st to 10th	Day	20% 15% 36% 19% 10%	270
	11th to 20th	Day	21% 14% 33% 23% 8%	270
	21st to end	Day	26% 18% 36% 17% 3	297
January	1st to 10th	Night	26% 13% 32% 24% 5%	950
	11th to 20th	Night	27% 14% 33% 20% 5%	950
	21st to end	Night	23% 12% 39% 24% 2	1009
February	1st to 10th	Night	26% 12% 36% 22% 4	760
	11th to 20th	Night	23% 14% 36% 25% 2	743
	21st to end	Night	26% 14% 38% 20% 1	628
March	1st to 10th	Night	20% 14% 32% 30% 4	760
	11th to 20th	Night	21% 10% 36% 26% 6% 1	720
	21st to end	Night	21% 11% 28% 32% 7%	627
April	1st to 10th	Night	15% 10% 35% 33% 7%	570
	11th to 20th	Night	18% 9% 31% 28% 13% 1	563
	21st to end	Night	18% 6% 32% 31% 11% 1	570
May	1st to 10th	Night	19% 5% 28% 31% 15% 2	570
	11th to 20th	Night	15% 4 18% 39% 20% 3	561
	21st to end	Night	7% 3 18% 37% 31% 5%	617
June	1st to 10th	Night	12% 3 14% 36% 30% 5%	570
	11th to 20th	Night	6% 1 12% 43% 35% 3	570
	21st to end	Night	3 2 13% 41% 36% 5%	570
July	1st to 10th	Night	8% 2 7% 28% 44% 11%	531
	11th to 20th	Night	7% 2 9% 27% 47% 9%	522
	21st to end	Night	7% 1 8% 34% 43% 9%	591
August	1st to 10th	Night	6% 1 5% 31% 49% 9%	537
	11th to 20th	Night	8% 2 6% 40% 38% 6%	534
	21st to end	Night	8% 1 5% 29% 47% 9%	594
September	1st to 10th	Night	11% 2 9% 31% 41% 6%	540
	11th to 20th	Night	11% 2 7% 31% 41% 8%	648
	21st to end	Night	11% 2 16% 34% 32% 5%	720
October	1st to 10th	Night	10% 4 17% 36% 28% 5%	720
	11th to 20th	Night	16% 5% 26% 34% 16% 3	720
	21st to end	Night	23% 5% 28% 31% 12% 1	792
November	1st to 10th	Night	14% 6% 27% 36% 16% 1	740
	11th to 20th	Night	14% 10% 32% 33% 11% 1	760
	21st to end	Night	22% 9% 27% 30% 11% 1	760
December	1st to 10th	Night	25% 9% 30% 29% 6% 1	760
	11th to 20th	Night	23% 8% 32% 29% 7%	904
	21st to end	Night	27% 11% 32% 26% 4	1045

Page generated at 2024-06-29 21:08:52. Version ac07

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