Hopkinsville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hopkinsville clear sky chart from 2005-11-06 to 2024-03-01.

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	14% 7% 3 6% 5% 3 5% 5% 5% 7% 41%	78629
	Night	14% 7% 3 5% 5% 3 4 4 5% 7% 43%	80797
Transparency	Day	42% 6% 11% 22% 16% 3	78338
	Night	41% 6% 10% 22% 17% 4	80609
Seeing	Day	16% 10% 23% 24% 18% 9%	14348
	Night	17% 8% 25% 30% 18% 2	24298

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	14% 11% 6% 9% 6% 4 5% 4 4 5% 32%	2527
	11th to 20th	Day	18% 9% 4 7% 7% 3 5% 5% 4 5% 34%	2530
	21st to end	Day	24% 11% 5% 6% 4 3 4 4 4 6% 29%	3281
February	1st to 10th	Day	18% 10% 4 5% 5% 3 4 4 5% 7% 36%	1900
	11th to 20th	Day	20% 9% 3 7% 5% 3 4 4 4 6% 36%	1848
	21st to end	Day	19% 9% 3 7% 6% 3 4 4 4 6% 36%	1570
March	1st to 10th	Day	16% 10% 3 6% 5% 3 4 4 4 5% 40%	1800
	11th to 20th	Day	22% 9% 4 7% 5% 2 3 3 5% 5% 34%	1854
	21st to end	Day	18% 9% 4 6% 6% 3 5% 4 5% 7% 33%	2361
April	1st to 10th	Day	12% 6% 3 6% 6% 3 4 4 5% 7% 44%	2160
	11th to 20th	Day	16% 6% 3 6% 6% 4 4 4 5% 6% 40%	2134
	21st to end	Day	16% 7% 3 5% 5% 3 4 4 5% 7% 41%	2168
May	1st to 10th	Day	17% 5% 3 5% 6% 2 5% 5% 5% 7% 40%	2340
	11th to 20th	Day	15% 6% 3 7% 6% 3 5% 5% 5% 6% 39%	2301
	21st to end	Day	8% 5% 2 6% 7% 4 6% 7% 7% 10% 37%	2531
June	1st to 10th	Day	10% 4 2 5% 5% 2 4 5% 6% 8% 47%	2501
	11th to 20th	Day	5% 4 2 4 6% 4 6% 6% 8% 10% 47%	2520
	21st to end	Day	6% 3 2 4 6% 4 6% 6% 7% 10% 46%	2520
July	1st to 10th	Day	8% 6% 3 6% 7% 5% 6% 6% 7% 10% 36%	2520
	11th to 20th	Day	8% 5% 2 6% 5% 4 6% 5% 6% 10% 44%	2520
	21st to end	Day	8% 5% 2 5% 6% 4 6% 6% 8% 10% 39%	2627
August	1st to 10th	Day	7% 5% 2 6% 6% 4 6% 7% 8% 11% 40%	2186
	11th to 20th	Day	9% 6% 3 6% 5% 4 5% 5% 7% 10% 41%	2125
	21st to end	Day	8% 5% 2 4 6% 4 5% 6% 6% 9% 45%	2376
September	1st to 10th	Day	11% 4 2 5% 6% 3 5% 5% 6% 8% 44%	2160
	11th to 20th	Day	11% 5% 3 6% 5% 4 4 5% 4 7% 47%	1994
	21st to end	Day	12% 5% 2 4 5% 3 4 4 4 8% 51%	1980
October	1st to 10th	Day	10% 4 3 3 4 2 3 3 4 7% 56%	1980
	11th to 20th	Day	13% 5% 2 4 4 3 3 4 3 7% 52%	1871
	21st to end	Day	19% 6% 2 5% 4 2 3 3 3 6% 46%	1824
November	1st to 10th	Day	11% 5% 2 5% 4 2 3 3 5% 6% 55%	1672
	11th to 20th	Day	16% 6% 2 4 3 2 3 5% 4 6% 49%	1710
	21st to end	Day	16% 8% 3 5% 5% 2 4 4 5% 4 44%	1710
December	1st to 10th	Day	20% 10% 3 5% 4 3 4 4 4 5% 38%	1710
	11th to 20th	Day	16% 12% 4 5% 6% 3 4 5% 5% 5% 36%	2035
	21st to end	Day	16% 12% 6% 6% 6% 4 5% 4 5% 7% 29%	2783
January	1st to 10th	Night	18% 10% 4 5% 4 2 4 5% 4 7% 37%	4428
	11th to 20th	Night	17% 11% 4 8% 6% 3 5% 4 4 5% 33%	4440
	21st to end	Night	24% 11% 5% 5% 4 3 3 3 4 5% 33%	4361
February	1st to 10th	Night	22% 9% 4 7% 5% 3 4 3 4 5% 33%	2280
	11th to 20th	Night	20% 7% 4 7% 5% 4 3 3 4 5% 38%	2218
	21st to end	Night	20% 9% 4 5% 5% 3 4 4 4 5% 34%	1884
March	1st to 10th	Night	17% 7% 3 5% 4 2 4 4 5% 5% 43%	2167
	11th to 20th	Night	18% 8% 3 7% 6% 3 3 4 5% 6% 38%	2106
	21st to end	Night	18% 8% 3 7% 4 3 5% 4 5% 6% 36%	2011
April	1st to 10th	Night	11% 4 2 5% 4 3 4 4 5% 8% 50%	1800
	11th to 20th	Night	14% 6% 3 4 5% 3 4 4 4 7% 46%	1775
	21st to end	Night	14% 6% 3 6% 5% 3 5% 5% 5% 9% 40%	1791
May	1st to 10th	Night	16% 6% 2 5% 4 3 4 3 5% 7% 44%	1620
	11th to 20th	Night	12% 5% 3 5% 6% 3 5% 5% 6% 9% 41%	1592
	21st to end	Night	6% 4 3 5% 5% 4 6% 6% 8% 11% 44%	1744
June	1st to 10th	Night	11% 6% 2 5% 5% 2 4 4 4 8% 48%	1455
	11th to 20th	Night	4 2 1 4 5% 2 4 5% 5% 10% 57%	1440
	21st to end	Night	3 2 1 4 4 4 5% 5% 8% 11% 53%	1440
July	1st to 10th	Night	7% 3 3 4 5% 3 5% 5% 8% 10% 46%	1440
	11th to 20th	Night	7% 4 2 5% 4 3 4 4 8% 10% 48%	1440
	21st to end	Night	7% 3 2 4 4 3 5% 6% 7% 10% 48%	1688
August	1st to 10th	Night	6% 3 2 5% 4 4 5% 6% 6% 9% 50%	1747
	11th to 20th	Night	5% 4 2 4 6% 4 4 6% 8% 9% 48%	1776
	21st to end	Night	6% 4 1 4 4 3 4 5% 6% 10% 52%	1980
September	1st to 10th	Night	12% 4 3 4 4 2 4 4 5% 7% 52%	1800
	11th to 20th	Night	9% 5% 2 5% 5% 2 4 5% 5% 6% 53%	1948
	21st to end	Night	9% 4 3 4 4 2 3 4 4 7% 56%	1980
October	1st to 10th	Night	8% 4 2 3 3 2 4 3 5% 6% 60%	1980
	11th to 20th	Night	16% 5% 3 4 3 2 3 3 4 4 52%	2087
	21st to end	Night	16% 7% 2 5% 5% 2 4 3 4 6% 46%	2529
November	1st to 10th	Night	12% 5% 3 4 4 2 3 3 3 5% 55%	2406
	11th to 20th	Night	14% 5% 3 4 4 2 4 3 5% 7% 50%	2470
	21st to end	Night	17% 6% 3 4 4 2 4 3 5% 5% 47%	2470
December	1st to 10th	Night	20% 10% 3 6% 4 2 4 5% 4 5% 36%	2470
	11th to 20th	Night	17% 8% 3 5% 5% 3 4 4 4 5% 42%	3150
	21st to end	Night	17% 12% 5% 7% 6% 4 5% 5% 4 6% 29%	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	54% 5% 7% 22% 10% 2	2528
	11th to 20th	Day	53% 4 9% 22% 12% 1	2530
	21st to end	Day	57% 4 8% 21% 9% 1	3281
February	1st to 10th	Day	50% 4 8% 23% 13% 2	1900
	11th to 20th	Day	50% 5% 7% 21% 13% 4	1858
	21st to end	Day	50% 4 8% 18% 14% 5%	1570
March	1st to 10th	Day	47% 5% 8% 20% 17% 4	1800
	11th to 20th	Day	52% 5% 10% 20% 11% 2	1854
	21st to end	Day	51% 6% 10% 20% 11% 2	2361
April	1st to 10th	Day	39% 5% 11% 23% 20% 2	2160
	11th to 20th	Day	44% 4 9% 21% 19% 3	2134
	21st to end	Day	43% 5% 10% 27% 13% 2	2168
May	1st to 10th	Day	43% 7% 12% 25% 12% 1	2340
	11th to 20th	Day	46% 7% 10% 22% 14% 1	2305
	21st to end	Day	39% 10% 16% 21% 12% 2	2531
June	1st to 10th	Day	34% 8% 13% 24% 20% 2	2501
	11th to 20th	Day	29% 9% 16% 25% 18% 3	2520
	21st to end	Day	30% 10% 16% 23% 16% 5%	2520
July	1st to 10th	Day	40% 10% 14% 20% 13% 4	2451
	11th to 20th	Day	35% 9% 16% 24% 13% 3	2445
	21st to end	Day	34% 11% 17% 25% 11% 3	2481
August	1st to 10th	Day	35% 11% 14% 26% 13% 1	2173
	11th to 20th	Day	38% 9% 12% 23% 15% 2	2125
	21st to end	Day	33% 9% 13% 24% 17% 4	2376
September	1st to 10th	Day	36% 8% 11% 24% 18% 3	2160
	11th to 20th	Day	37% 6% 9% 22% 22% 3	1994
	21st to end	Day	33% 6% 9% 25% 22% 6%	1980
October	1st to 10th	Day	30% 5% 9% 24% 27% 5%	1980
	11th to 20th	Day	35% 4 7% 22% 24% 8%	1871
	21st to end	Day	41% 4 7% 23% 20% 4	1824
November	1st to 10th	Day	31% 5% 9% 24% 26% 5%	1672
	11th to 20th	Day	36% 4 8% 23% 22% 6%	1710
	21st to end	Day	43% 3 7% 25% 17% 4	1710
December	1st to 10th	Day	48% 5% 10% 22% 13% 2	1710
	11th to 20th	Day	49% 6% 10% 20% 14% 2	2032
	21st to end	Day	54% 6% 12% 17% 10%	2783
January	1st to 10th	Night	47% 4 8% 26% 13% 1	4428
	11th to 20th	Night	53% 5% 9% 18% 13% 3	4440
	21st to end	Night	54% 4 9% 22% 11% 1	4361
February	1st to 10th	Night	55% 4 9% 18% 14% 1	2280
	11th to 20th	Night	50% 4 6% 21% 14% 4	2219
	21st to end	Night	52% 5% 8% 15% 15% 4	1884
March	1st to 10th	Night	43% 5% 8% 18% 20% 6%	2167
	11th to 20th	Night	48% 5% 9% 21% 13% 3	2106
	21st to end	Night	48% 7% 11% 20% 12% 2	2011
April	1st to 10th	Night	33% 5% 11% 26% 21% 3	1800
	11th to 20th	Night	38% 5% 10% 19% 22% 6%	1775
	21st to end	Night	40% 5% 10% 25% 18% 2	1791
May	1st to 10th	Night	40% 6% 10% 24% 17% 3	1620
	11th to 20th	Night	38% 9% 15% 22% 15% 1	1593
	21st to end	Night	31% 10% 17% 24% 15% 3	1745
June	1st to 10th	Night	36% 5% 12% 24% 21% 3	1455
	11th to 20th	Night	22% 8% 17% 27% 22% 4	1440
	21st to end	Night	24% 8% 17% 28% 16% 6%	1440
July	1st to 10th	Night	31% 9% 16% 26% 15% 4	1400
	11th to 20th	Night	29% 9% 17% 24% 17% 4	1392
	21st to end	Night	28% 11% 15% 30% 14% 2	1594
August	1st to 10th	Night	29% 10% 15% 26% 20% 1	1736
	11th to 20th	Night	28% 10% 18% 24% 18% 2	1776
	21st to end	Night	27% 8% 14% 28% 18% 5%	1980
September	1st to 10th	Night	32% 6% 11% 26% 20% 5%	1800
	11th to 20th	Night	31% 6% 8% 26% 25% 5%	1948
	21st to end	Night	29% 5% 8% 24% 27% 7%	1980
October	1st to 10th	Night	26% 5% 9% 24% 29% 7%	1980
	11th to 20th	Night	37% 3 8% 20% 25% 7%	2087
	21st to end	Night	40% 4 6% 23% 22% 5%	2529
November	1st to 10th	Night	33% 3 7% 24% 26% 6%	2406
	11th to 20th	Night	35% 4 6% 24% 23% 9%	2470
	21st to end	Night	39% 4 8% 25% 20% 4	2470
December	1st to 10th	Night	50% 5% 10% 20% 13% 2	2470
	11th to 20th	Night	44% 4 10% 22% 18% 3	3152
	21st to end	Night	56% 6% 9% 16% 11% 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	26% 22% 31% 16% 5%	270
	11th to 20th	Day	26% 24% 32% 15% 3	270
	21st to end	Day	21% 23% 41% 12% 3	297
February	1st to 10th	Day	27% 19% 35% 15% 3 1	270
	11th to 20th	Day	29% 23% 37% 8% 2	270
	21st to end	Day	31% 24% 31% 10% 4	225
March	1st to 10th	Day	25% 19% 38% 14% 3	240
	11th to 20th	Day	24% 21% 35% 14% 5% 1	294
	21st to end	Day	26% 17% 32% 18% 6% 1	462
April	1st to 10th	Day	19% 16% 30% 26% 8% 1	420
	11th to 20th	Day	22% 14% 26% 24% 13% 1	412
	21st to end	Day	22% 13% 29% 23% 9% 3	420
May	1st to 10th	Day	21% 14% 28% 25% 9% 4	423
	11th to 20th	Day	17% 8% 22% 31% 15% 6%	447
	21st to end	Day	10% 4 19% 31% 21% 15%	485
June	1st to 10th	Day	11% 4 17% 27% 27% 14%	611
	11th to 20th	Day	5% 3 18% 32% 29% 12%	630
	21st to end	Day	5% 3 20% 33% 25% 13%	630
July	1st to 10th	Day	10% 2 12% 25% 29% 22%	621
	11th to 20th	Day	9% 3 13% 27% 31% 18%	618
	21st to end	Day	7% 2 14% 29% 29% 19%	568
August	1st to 10th	Day	10% 3 12% 28% 30% 16%	446
	11th to 20th	Day	14% 2 13% 31% 30% 11%	439
	21st to end	Day	11% 1 9% 21% 38% 19%	495
September	1st to 10th	Day	11% 2 13% 26% 34% 14%	450
	11th to 20th	Day	10% 2 10% 25% 37% 16%	450
	21st to end	Day	16% 6% 18% 26% 23% 11%	450
October	1st to 10th	Day	10% 5% 20% 34% 24% 7%	450
	11th to 20th	Day	13% 14% 27% 30% 11% 4	341
	21st to end	Day	28% 14% 24% 25% 8% 2	297
November	1st to 10th	Day	15% 7% 39% 23% 14% 2	270
	11th to 20th	Day	16% 19% 34% 24% 7% 1	270
	21st to end	Day	23% 13% 33% 20% 10% 2	270
December	1st to 10th	Day	26% 17% 30% 18% 9%	270
	11th to 20th	Day	23% 16% 34% 21% 6%	270
	21st to end	Day	27% 19% 34% 17% 3	297
January	1st to 10th	Night	25% 14% 31% 26% 3	950
	11th to 20th	Night	27% 14% 33% 21% 4	950
	21st to end	Night	23% 13% 39% 22% 3	932
February	1st to 10th	Night	26% 14% 33% 25% 2	760
	11th to 20th	Night	25% 14% 38% 22% 2	743
	21st to end	Night	29% 14% 35% 21% 1	628
March	1st to 10th	Night	21% 14% 32% 28% 5%	723
	11th to 20th	Night	21% 12% 35% 25% 6% 1	720
	21st to end	Night	20% 12% 30% 29% 8% 1	625
April	1st to 10th	Night	14% 10% 34% 33% 8% 1	540
	11th to 20th	Night	18% 10% 30% 29% 13% 1	533
	21st to end	Night	17% 7% 31% 33% 10% 1	540
May	1st to 10th	Night	18% 8% 31% 27% 15% 2	540
	11th to 20th	Night	13% 5% 21% 37% 21% 3	531
	21st to end	Night	8% 2 15% 39% 30% 5%	584
June	1st to 10th	Night	14% 3 13% 35% 31% 3	540
	11th to 20th	Night	5% 2 12% 42% 36% 3	540
	21st to end	Night	3 1 14% 41% 36% 6%	540
July	1st to 10th	Night	8% 2 6% 30% 43% 10%	525
	11th to 20th	Night	7% 3 9% 26% 48% 7%	522
	21st to end	Night	7% 2 10% 35% 37% 8%	591
August	1st to 10th	Night	7% 1 7% 32% 45% 8%	537
	11th to 20th	Night	6% 1 9% 41% 38% 4	534
	21st to end	Night	8% 1 8% 30% 44% 8%	594
September	1st to 10th	Night	13% 2 11% 30% 38% 6%	540
	11th to 20th	Night	11% 1 11% 31% 40% 6%	688
	21st to end	Night	11% 3 20% 30% 31% 5%	720
October	1st to 10th	Night	11% 4 18% 33% 28% 5%	720
	11th to 20th	Night	19% 6% 24% 34% 16% 2	720
	21st to end	Night	19% 8% 30% 28% 14% 1	792
November	1st to 10th	Night	14% 7% 27% 35% 16% 1	740
	11th to 20th	Night	15% 10% 33% 29% 11% 1	760
	21st to end	Night	21% 11% 28% 28% 11% 1	760
December	1st to 10th	Night	25% 11% 29% 29% 6%	760
	11th to 20th	Night	24% 9% 31% 29% 6% 1	831
	21st to end	Night	28% 11% 31% 26% 4	1045

Page generated at 2024-02-27 05:30:12. Version ac07

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