Morehead State University
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Morehead State University clear sky chart from 2005-11-06 to 2024-11-12.

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	15% 9% 3 7% 5% 4 4 4 6% 7% 36%	101182
	Night	15% 10% 3 7% 4 4 4 3 5% 7% 38%	97977
Transparency	Day	45% 5% 10% 23% 15% 2	104913
	Night	44% 5% 10% 22% 16% 3	102384
Seeing	Day	22% 12% 26% 21% 13% 6%	14860
	Night	20% 10% 25% 28% 16% 2	24910

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% 17% 7% 10% 5% 4 4 4 5% 7% 23%	2836
	11th to 20th	Day	16% 16% 8% 14% 6% 5% 4 2 3 3 23%	2840
	21st to end	Day	26% 17% 7% 7% 4 3 3 2 4 5% 22%	3124
February	1st to 10th	Day	19% 13% 5% 11% 5% 4 3 3 3 6% 29%	1775
	11th to 20th	Day	20% 11% 4 9% 4 4 4 4 4 5% 30%	1848
	21st to end	Day	20% 13% 4 8% 4 3 5% 2 4 6% 31%	1570
March	1st to 10th	Day	23% 15% 3 7% 3 3 3 3 5% 5% 29%	3242
	11th to 20th	Day	15% 7% 2 7% 4 3 4 3 6% 7% 43%	3480
	21st to end	Day	17% 8% 3 6% 4 4 4 3 6% 8% 36%	3815
April	1st to 10th	Day	14% 10% 3 8% 5% 5% 4 3 5% 6% 37%	2144
	11th to 20th	Day	17% 8% 3 6% 5% 4 4 3 4 6% 39%	2342
	21st to end	Day	18% 8% 2 6% 5% 5% 4 4 4 7% 36%	2470
May	1st to 10th	Day	19% 10% 4 8% 5% 5% 5% 4 6% 7% 28%	4082
	11th to 20th	Day	18% 9% 3 7% 5% 4 4 3 5% 7% 34%	4081
	21st to end	Day	11% 7% 2 7% 5% 6% 6% 5% 8% 10% 33%	4476
June	1st to 10th	Day	11% 6% 2 6% 5% 6% 5% 5% 6% 8% 41%	2470
	11th to 20th	Day	9% 6% 2 7% 5% 6% 6% 4 6% 9% 41%	2470
	21st to end	Day	10% 6% 2 6% 6% 5% 6% 5% 6% 9% 40%	2470
July	1st to 10th	Day	10% 7% 2 7% 5% 4 6% 5% 7% 11% 37%	4120
	11th to 20th	Day	8% 6% 2 7% 5% 5% 5% 5% 7% 10% 40%	4120
	21st to end	Day	17% 10% 4 9% 6% 6% 6% 5% 6% 8% 25%	4466
August	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 4 8% 10% 41%	4104
	11th to 20th	Day	9% 7% 2 6% 5% 5% 6% 5% 7% 10% 38%	4044
	21st to end	Day	5% 4 1 5% 4 4 4 3 6% 9% 55%	4308
September	1st to 10th	Day	13% 5% 3 5% 4 4 4 3 5% 7% 46%	2100
	11th to 20th	Day	11% 6% 2 6% 4 4 4 3 5% 9% 47%	2090
	21st to end	Day	18% 6% 3 6% 4 3 3 3 5% 6% 44%	2090
October	1st to 10th	Day	11% 5% 2 5% 4 3 3 2 6% 7% 51%	2080
	11th to 20th	Day	14% 7% 2 5% 3 3 4 3 5% 5% 49%	1900
	21st to end	Day	20% 7% 3 6% 4 3 3 2 4 6% 42%	2047
November	1st to 10th	Day	12% 7% 2 5% 4 4 4 2 3 5% 52%	1762
	11th to 20th	Day	14% 10% 3 6% 5% 4 4 3 4 6% 41%	1719
	21st to end	Day	17% 11% 3 6% 4 4 4 3 4 5% 39%	1710
December	1st to 10th	Day	24% 14% 4 8% 3 3 4 3 5% 5% 27%	1710
	11th to 20th	Day	18% 14% 4 9% 4 4 4 3 5% 5% 32%	2153
	21st to end	Day	17% 19% 4 10% 5% 5% 4 4 5% 6% 21%	3124
January	1st to 10th	Night	15% 18% 5% 12% 6% 4 4 3 4 5% 23%	4109
	11th to 20th	Night	19% 16% 5% 11% 5% 3 3 2 3 4 27%	4120
	21st to end	Night	24% 14% 6% 8% 5% 3 3 2 4 5% 26%	4532
February	1st to 10th	Night	20% 13% 5% 9% 4 4 4 4 4 4 29%	2404
	11th to 20th	Night	20% 12% 4 9% 5% 4 3 3 3 5% 31%	2218
	21st to end	Night	22% 13% 4 9% 4 5% 4 3 4 5% 27%	1884
March	1st to 10th	Night	21% 14% 3 6% 4 4 4 3 4 6% 32%	3610
	11th to 20th	Night	14% 8% 3 6% 4 4 3 3 5% 6% 45%	3480
	21st to end	Night	12% 9% 2 7% 5% 5% 5% 4 6% 8% 38%	3817
April	1st to 10th	Night	15% 8% 2 6% 4 4 4 4 6% 8% 40%	2051
	11th to 20th	Night	15% 8% 2 5% 4 4 3 4 5% 8% 43%	1787
	21st to end	Night	17% 7% 3 6% 5% 3 5% 4 5% 6% 39%	1710
May	1st to 10th	Night	22% 10% 4 8% 5% 4 4 4 6% 6% 27%	2813
	11th to 20th	Night	19% 9% 2 6% 3 4 4 4 5% 8% 37%	2812
	21st to end	Night	9% 6% 2 6% 5% 4 4 4 7% 10% 43%	3079
June	1st to 10th	Night	9% 5% 2 5% 4 5% 5% 4 8% 9% 44%	1710
	11th to 20th	Night	6% 4 3 5% 5% 4 6% 5% 7% 11% 46%	1710
	21st to end	Night	8% 4 2 6% 5% 5% 5% 5% 8% 11% 43%	1710
July	1st to 10th	Night	8% 5% 2 6% 4 5% 5% 4 6% 10% 44%	2840
	11th to 20th	Night	7% 5% 2 6% 5% 4 4 4 7% 9% 46%	2840
	21st to end	Night	13% 10% 3 8% 6% 5% 4 4 6% 8% 33%	3087
August	1st to 10th	Night	7% 6% 2 7% 5% 5% 5% 4 7% 10% 41%	2825
	11th to 20th	Night	11% 6% 2 6% 5% 5% 5% 4 6% 8% 42%	2785
	21st to end	Night	4 4 2 4 3 3 4 3 6% 9% 58%	3343
September	1st to 10th	Night	10% 6% 2 5% 4 5% 5% 3 5% 8% 48%	2059
	11th to 20th	Night	10% 6% 3 5% 4 4 3 3 5% 7% 50%	2090
	21st to end	Night	12% 7% 2 6% 5% 4 4 3 4 7% 46%	2090
October	1st to 10th	Night	10% 4 2 5% 4 3 3 3 5% 7% 53%	2099
	11th to 20th	Night	15% 5% 2 5% 4 3 4 3 4 7% 48%	2280
	21st to end	Night	17% 7% 2 7% 4 4 3 3 4 6% 44%	2549
November	1st to 10th	Night	11% 8% 3 5% 3 4 4 3 4 6% 49%	2536
	11th to 20th	Night	15% 9% 3 6% 4 4 3 3 5% 6% 42%	2484
	21st to end	Night	17% 11% 3 5% 4 3 3 3 5% 6% 39%	2470
December	1st to 10th	Night	22% 13% 4 7% 4 4 3 3 5% 5% 30%	2470
	11th to 20th	Night	17% 13% 5% 10% 4 4 3 3 4 6% 31%	3042
	21st to end	Night	18% 19% 5% 9% 5% 5% 5% 3 5% 6% 20%	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	61% 4 10% 15% 9% 1	2837
	11th to 20th	Day	68% 3 6% 17% 5% 1	2840
	21st to end	Day	65% 3 7% 19% 5% 1	3124
February	1st to 10th	Day	59% 4 8% 18% 11% 1	1775
	11th to 20th	Day	57% 4 8% 19% 11% 2	1858
	21st to end	Day	56% 4 7% 19% 11% 3	1570
March	1st to 10th	Day	58% 4 8% 18% 10% 3	3242
	11th to 20th	Day	40% 4 12% 25% 17% 1	3480
	21st to end	Day	45% 6% 9% 26% 12% 1	3815
April	1st to 10th	Day	48% 4 9% 23% 13% 3	2144
	11th to 20th	Day	45% 5% 8% 20% 17% 4	2342
	21st to end	Day	47% 6% 11% 22% 12% 3	2470
May	1st to 10th	Day	53% 7% 11% 20% 9% 1	4120
	11th to 20th	Day	50% 6% 9% 22% 12% 1	4085
	21st to end	Day	41% 10% 14% 18% 16% 2	4489
June	1st to 10th	Day	40% 8% 11% 25% 16% 1	2470
	11th to 20th	Day	38% 9% 13% 21% 18% 2	2470
	21st to end	Day	40% 8% 12% 21% 16% 3	2470
July	1st to 10th	Day	40% 8% 15% 22% 14% 1	4055
	11th to 20th	Day	37% 7% 11% 33% 12% 1	4051
	21st to end	Day	56% 6% 10% 16% 11% 1	4324
August	1st to 10th	Day	36% 8% 15% 30% 11% 1	4091
	11th to 20th	Day	39% 7% 10% 30% 14% 1	4083
	21st to end	Day	26% 6% 14% 32% 20% 2	4307
September	1st to 10th	Day	38% 6% 12% 20% 19% 6%	2100
	11th to 20th	Day	36% 5% 11% 24% 22% 2	2090
	21st to end	Day	41% 4 9% 23% 20% 2	2090
October	1st to 10th	Day	23% 4 8% 25% 37% 2	3457
	11th to 20th	Day	27% 3 9% 29% 29% 2	3140
	21st to end	Day	32% 2 10% 29% 22% 5%	3349
November	1st to 10th	Day	37% 4 7% 26% 22% 4	1762
	11th to 20th	Day	45% 3 8% 22% 19% 3	1719
	21st to end	Day	49% 3 8% 19% 18% 2	1710
December	1st to 10th	Day	59% 4 11% 18% 8% 1	1710
	11th to 20th	Day	56% 3 10% 17% 14% 1	2150
	21st to end	Day	63% 4 11% 16% 5% 1	3124
January	1st to 10th	Night	61% 5% 9% 16% 8% 1	4109
	11th to 20th	Night	62% 3 7% 18% 9% 2	4120
	21st to end	Night	61% 3 8% 19% 8% 1	4532
February	1st to 10th	Night	57% 4 9% 18% 11% 1	2404
	11th to 20th	Night	57% 3 8% 19% 12% 1	2219
	21st to end	Night	61% 3 9% 14% 10% 3	1884
March	1st to 10th	Night	54% 4 6% 21% 13% 2	3610
	11th to 20th	Night	39% 5% 9% 28% 17% 2	3480
	21st to end	Night	43% 6% 11% 24% 16% 1	3817
April	1st to 10th	Night	40% 6% 11% 22% 18% 2	2051
	11th to 20th	Night	40% 5% 10% 20% 18% 6%	1787
	21st to end	Night	45% 6% 11% 22% 14% 2	1710
May	1st to 10th	Night	55% 7% 10% 17% 9% 2	2840
	11th to 20th	Night	45% 7% 12% 24% 10% 1	2813
	21st to end	Night	33% 9% 14% 22% 18% 3	3087
June	1st to 10th	Night	33% 8% 15% 25% 16% 4	1710
	11th to 20th	Night	31% 9% 14% 24% 19% 3	1710
	21st to end	Night	33% 9% 14% 24% 15% 5%	1710
July	1st to 10th	Night	35% 8% 13% 23% 17% 3	2795
	11th to 20th	Night	32% 7% 13% 30% 16% 2	2786
	21st to end	Night	49% 7% 9% 21% 13% 2	2988
August	1st to 10th	Night	35% 8% 14% 29% 12% 1	2814
	11th to 20th	Night	39% 6% 10% 27% 17% 1	2812
	21st to end	Night	22% 7% 14% 32% 21% 4	3343
September	1st to 10th	Night	34% 6% 12% 20% 19% 8%	2059
	11th to 20th	Night	33% 5% 11% 22% 25% 4	2090
	21st to end	Night	39% 6% 8% 21% 24% 2	2090
October	1st to 10th	Night	26% 4 7% 24% 36% 3	3502
	11th to 20th	Night	26% 3 7% 26% 31% 7%	3779
	21st to end	Night	31% 3 8% 23% 28% 8%	4197
November	1st to 10th	Night	38% 4 8% 24% 22% 5%	2536
	11th to 20th	Night	43% 4 8% 18% 22% 5%	2484
	21st to end	Night	46% 4 10% 23% 15% 2	2470
December	1st to 10th	Night	56% 5% 10% 18% 10% 1	2470
	11th to 20th	Night	55% 3 8% 21% 12% 1	3044
	21st to end	Night	63% 5% 10% 14% 8%	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	30% 21% 33% 13% 2 1	270
	11th to 20th	Day	40% 20% 30% 10%	270
	21st to end	Day	32% 28% 27% 11% 1	297
February	1st to 10th	Day	33% 24% 29% 12% 3	270
	11th to 20th	Day	39% 27% 28% 4 2	270
	21st to end	Day	37% 20% 36% 6% 1	225
March	1st to 10th	Day	35% 20% 29% 12% 4	340
	11th to 20th	Day	28% 23% 31% 14% 4	460
	21st to end	Day	31% 20% 28% 15% 5%	506
April	1st to 10th	Day	28% 19% 26% 19% 7% 1	460
	11th to 20th	Day	22% 19% 31% 18% 7% 3	452
	21st to end	Day	25% 18% 32% 17% 5% 2	460
May	1st to 10th	Day	26% 17% 28% 17% 8% 3	463
	11th to 20th	Day	22% 11% 29% 20% 13% 5%	487
	21st to end	Day	15% 8% 25% 27% 16% 8%	529
June	1st to 10th	Day	14% 8% 24% 31% 15% 8%	490
	11th to 20th	Day	11% 7% 25% 32% 16% 8%	490
	21st to end	Day	12% 7% 28% 26% 18% 9%	490
July	1st to 10th	Day	15% 6% 17% 23% 19% 19%	485
	11th to 20th	Day	11% 6% 23% 30% 19% 12%	484
	21st to end	Day	15% 4 21% 28% 20% 12%	532
August	1st to 10th	Day	15% 3 20% 27% 22% 14%	486
	11th to 20th	Day	15% 4 18% 32% 21% 10%	479
	21st to end	Day	9% 5% 15% 31% 26% 14%	539
September	1st to 10th	Day	15% 4 17% 23% 28% 12%	490
	11th to 20th	Day	13% 4 17% 26% 28% 12%	490
	21st to end	Day	21% 8% 20% 24% 22% 5%	490
October	1st to 10th	Day	15% 6% 23% 30% 20% 6%	490
	11th to 20th	Day	18% 12% 29% 22% 14% 5%	490
	21st to end	Day	24% 12% 31% 24% 8% 1	496
November	1st to 10th	Day	18% 13% 36% 24% 7% 2	300
	11th to 20th	Day	30% 16% 29% 18% 6% 1	273
	21st to end	Day	29% 15% 37% 15% 4 1	270
December	1st to 10th	Day	32% 22% 29% 13% 4	270
	11th to 20th	Day	29% 18% 33% 14% 5%	270
	21st to end	Day	34% 21% 32% 11% 1	297
January	1st to 10th	Night	27% 20% 30% 19% 4	760
	11th to 20th	Night	32% 18% 29% 18% 3	760
	21st to end	Night	26% 18% 34% 20% 2	836
February	1st to 10th	Night	29% 14% 34% 21% 2	760
	11th to 20th	Night	30% 20% 32% 17% 1	743
	21st to end	Night	34% 15% 34% 16% 1	628
March	1st to 10th	Night	27% 16% 30% 22% 5%	760
	11th to 20th	Night	26% 18% 29% 20% 7%	760
	21st to end	Night	21% 16% 31% 26% 7%	836
April	1st to 10th	Night	23% 13% 30% 26% 7%	721
	11th to 20th	Night	21% 11% 29% 27% 12% 1	563
	21st to end	Night	21% 9% 34% 28% 7% 1	570
May	1st to 10th	Night	20% 9% 28% 27% 13% 2	570
	11th to 20th	Night	18% 7% 23% 34% 17% 2	561
	21st to end	Night	11% 2 21% 33% 29% 4	617
June	1st to 10th	Night	10% 4 21% 41% 21% 3	570
	11th to 20th	Night	8% 3 17% 41% 28% 4	570
	21st to end	Night	11% 2 21% 36% 26% 4	570
July	1st to 10th	Night	14% 2 15% 28% 31% 9%	555
	11th to 20th	Night	6% 2 13% 38% 36% 5%	552
	21st to end	Night	13% 2 11% 35% 34% 5%	624
August	1st to 10th	Night	11% 2 9% 35% 37% 7%	567
	11th to 20th	Night	11% 2 10% 37% 33% 7%	564
	21st to end	Night	10% 1 11% 33% 37% 7%	627
September	1st to 10th	Night	12% 3 13% 32% 34% 5%	729
	11th to 20th	Night	13% 3 15% 29% 34% 6%	760
	21st to end	Night	14% 6% 21% 30% 27% 2	760
October	1st to 10th	Night	13% 6% 18% 32% 27% 4	760
	11th to 20th	Night	18% 8% 27% 29% 16% 2	760
	21st to end	Night	21% 12% 27% 26% 13% 2	836
November	1st to 10th	Night	17% 9% 27% 30% 16% 2	780
	11th to 20th	Night	22% 13% 29% 25% 10%	765
	21st to end	Night	24% 14% 24% 28% 9% 1	760
December	1st to 10th	Night	30% 16% 26% 24% 4	760
	11th to 20th	Night	25% 13% 32% 24% 6% 1	760
	21st to end	Night	29% 16% 28% 24% 3	836

Page generated at 2024-11-08 22:45:35. Version ac07

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