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 2024-11-30.

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 5% 7% 43%	101182
	Night	13% 7% 2 6% 4 4 4 3 5% 7% 45%	98417
Transparency	Day	21% 47% 6% 14% 10% 2	104870
	Night	20% 47% 5% 14% 11% 2	102870
Seeing	Day	16% 8% 23% 25% 19% 9%	15468
	Night	17% 7% 24% 30% 18% 3	25257

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% 5% 6% 6% 5% 8% 10% 39%	4440
	11th to 20th	Day	7% 4 2 5% 4 4 5% 5% 6% 11% 47%	4440
	21st to end	Day	12% 10% 3 9% 7% 5% 6% 5% 6% 8% 29%	4632
August	1st to 10th	Day	4 3 1 5% 4 4 4 5% 6% 9% 56%	3785
	11th to 20th	Day	9% 5% 2 7% 5% 5% 5% 4 6% 10% 44%	3729
	21st to end	Day	6% 4 1 5% 3 3 4 3 5% 9% 58%	4180
September	1st to 10th	Day	11% 5% 2 5% 4 4 4 3 5% 8% 48%	2280
	11th to 20th	Day	13% 5% 2 5% 4 4 4 4 5% 6% 48%	2144
	21st to end	Day	12% 6% 2 5% 4 3 3 3 5% 7% 52%	2090
October	1st to 10th	Day	9% 5% 2 4 3 3 3 2 5% 6% 57%	2090
	11th to 20th	Day	12% 6% 2 6% 3 3 3 2 4 5% 54%	1909
	21st to end	Day	18% 7% 2 4 4 2 3 3 5% 5% 48%	1984
November	1st to 10th	Day	12% 6% 2 5% 3 3 3 3 3 7% 53%	1762
	11th to 20th	Day	14% 8% 2 6% 3 3 3 2 5% 6% 49%	1800
	21st to end	Day	18% 8% 2 6% 3 3 4 3 5% 5% 43%	1797
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 5% 5% 6% 8% 13% 52%	1520
July	1st to 10th	Night	7% 4 2 6% 5% 4 6% 5% 7% 10% 45%	2530
	11th to 20th	Night	5% 4 2 5% 3 4 3 4 5% 9% 56%	2530
	21st to end	Night	8% 6% 3 10% 6% 5% 6% 5% 7% 9% 34%	2921
August	1st to 10th	Night	3 2 1 5% 3 4 4 3 6% 7% 62%	3144
	11th to 20th	Night	4 4 2 5% 4 4 5% 4 7% 9% 53%	3100
	21st to end	Night	4 3 1 4 3 3 3 3 5% 8% 63%	3476
September	1st to 10th	Night	9% 5% 2 5% 3 4 3 3 5% 6% 55%	1900
	11th to 20th	Night	9% 5% 2 5% 4 3 3 3 5% 8% 53%	2015
	21st to end	Night	9% 5% 1 5% 3 3 4 2 4 7% 54%	2090
October	1st to 10th	Night	8% 4 2 4 3 3 3 3 4 6% 61%	2090
	11th to 20th	Night	14% 4 2 5% 3 3 3 3 4 5% 55%	2268
	21st to end	Night	18% 7% 2 5% 3 3 4 3 4 5% 48%	2612
November	1st to 10th	Night	13% 5% 2 5% 3 2 2 2 5% 5% 55%	2536
	11th to 20th	Night	12% 7% 2 5% 3 3 4 3 5% 6% 51%	2600
	21st to end	Night	17% 7% 2 5% 3 3 3 3 4 6% 48%	2599
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	25% 40% 11% 19% 5% 1	4371
	11th to 20th	Day	18% 38% 8% 30% 6%	4365
	21st to end	Day	39% 38% 6% 12% 5%	4485
August	1st to 10th	Day	13% 39% 10% 19% 18% 1	3773
	11th to 20th	Day	22% 39% 9% 16% 13% 1	3765
	21st to end	Day	13% 38% 7% 25% 17%	4179
September	1st to 10th	Day	10% 61% 5% 13% 8% 3	2280
	11th to 20th	Day	12% 60% 5% 11% 10% 2	2144
	21st to end	Day	15% 60% 4 14% 7% 1	2090
October	1st to 10th	Day	9% 36% 3 10% 34% 8%	3480
	11th to 20th	Day	11% 37% 4 16% 20% 11%	3149
	21st to end	Day	16% 37% 2 19% 22% 4	3248
November	1st to 10th	Day	19% 56% 3 9% 11% 1	1762
	11th to 20th	Day	16% 57% 3 10% 12% 3	1800
	21st to end	Day	21% 57% 2 11% 8% 1	1797
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% 7% 12% 6%	1520
July	1st to 10th	Night	23% 39% 10% 20% 7% 1	2490
	11th to 20th	Night	14% 37% 6% 30% 11% 1	2482
	21st to end	Night	34% 39% 7% 14% 6%	2829
August	1st to 10th	Night	11% 39% 8% 26% 15%	3132
	11th to 20th	Night	16% 40% 12% 21% 10% 1	3130
	21st to end	Night	9% 38% 6% 27% 19% 1	3476
September	1st to 10th	Night	9% 60% 4 15% 10% 2	1900
	11th to 20th	Night	10% 61% 5% 13% 10% 2	2015
	21st to end	Night	12% 60% 4 14% 9% 1	2090
October	1st to 10th	Night	8% 37% 2 9% 34% 9%	3480
	11th to 20th	Night	9% 36% 2 11% 31% 12%	3767
	21st to end	Night	14% 36% 4 17% 20% 8%	4298
November	1st to 10th	Night	19% 56% 3 11% 9% 2	2536
	11th to 20th	Night	14% 57% 2 10% 13% 4	2600
	21st to end	Night	18% 57% 3 13% 9% 1	2599
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 19% 33% 24% 15%	680
July	1st to 10th	Day	10% 2 11% 25% 30% 22%	671
	11th to 20th	Day	9% 1 11% 26% 34% 19%	668
	21st to end	Day	8% 3 14% 26% 31% 18%	682
August	1st to 10th	Day	11% 3 6% 30% 34% 17%	486
	11th to 20th	Day	11% 4 10% 32% 33% 10%	479
	21st to end	Day	12% 1 5% 25% 35% 22%	539
September	1st to 10th	Day	12% 2 9% 27% 32% 18%	490
	11th to 20th	Day	12% 2 9% 25% 33% 18%	490
	21st to end	Day	16% 6% 15% 27% 24% 12%	490
October	1st to 10th	Day	12% 3 17% 34% 27% 7%	490
	11th to 20th	Day	15% 9% 32% 23% 16% 4	309
	21st to end	Day	25% 10% 29% 21% 12% 2	330
November	1st to 10th	Day	16% 9% 36% 23% 13% 3	300
	11th to 20th	Day	16% 12% 36% 26% 9% 1	300
	21st to end	Day	24% 10% 29% 26% 9% 1	299
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 14% 41% 36% 5%	570
July	1st to 10th	Night	8% 2 7% 29% 43% 11%	555
	11th to 20th	Night	7% 1 9% 29% 46% 9%	552
	21st to end	Night	8% 1 8% 34% 41% 8%	624
August	1st to 10th	Night	5% 1 6% 31% 48% 8%	567
	11th to 20th	Night	8% 2 6% 40% 38% 5%	564
	21st to end	Night	8% 1 5% 29% 47% 10%	627
September	1st to 10th	Night	11% 2 9% 31% 40% 6%	570
	11th to 20th	Night	12% 2 7% 31% 40% 8%	685
	21st to end	Night	12% 2 17% 34% 31% 5%	760
October	1st to 10th	Night	10% 3 17% 36% 29% 5%	760
	11th to 20th	Night	15% 5% 26% 34% 17% 3	760
	21st to end	Night	21% 5% 28% 31% 13% 1	836
November	1st to 10th	Night	15% 7% 26% 36% 15% 1	780
	11th to 20th	Night	14% 10% 32% 33% 11% 1	800
	21st to end	Night	22% 10% 27% 30% 11% 1	800
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 2024-11-27 16:30:48. Version ac07

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