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 2026-08-15.

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% 3 7% 5% 4 5% 4 6% 8% 40%	143368
	Night	13% 7% 3 7% 4 4 4 3 5% 7% 42%	138683
Transparency	Day	40% 6% 11% 24% 16% 3	147015
	Night	40% 5% 10% 23% 18% 4	143098
Seeing	Day	16% 10% 24% 24% 18% 8%	17770
	Night	17% 8% 25% 30% 17% 2	27469

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% 7% 10% 5% 4 4 3 4 5% 32%	4691
	11th to 20th	Day	11% 8% 3 8% 5% 3 3 2 4 5% 47%	4710
	21st to end	Day	20% 9% 4 7% 4 4 4 3 4 6% 37%	6112
February	1st to 10th	Day	17% 10% 4 7% 5% 4 4 3 5% 6% 35%	2100
	11th to 20th	Day	20% 9% 3 8% 4 3 4 3 4 6% 35%	2048
	21st to end	Day	18% 9% 3 8% 5% 3 4 3 4 5% 37%	1730
March	1st to 10th	Day	16% 13% 3 8% 4 4 3 3 4 5% 37%	4580
	11th to 20th	Day	13% 8% 3 6% 4 3 3 2 4 6% 48%	4761
	21st to end	Day	12% 8% 3 7% 4 4 4 3 5% 6% 43%	6069
April	1st to 10th	Day	13% 6% 2 7% 5% 4 4 4 5% 7% 43%	2520
	11th to 20th	Day	15% 7% 3 7% 5% 5% 3 4 6% 6% 40%	2494
	21st to end	Day	14% 8% 2 6% 4 4 4 3 5% 8% 41%	2530
May	1st to 10th	Day	16% 8% 3 8% 5% 5% 5% 5% 6% 8% 32%	7616
	11th to 20th	Day	14% 7% 3 8% 5% 5% 5% 4 5% 8% 37%	7626
	21st to end	Day	18% 9% 3 8% 5% 5% 5% 4 6% 7% 30%	8391
June	1st to 10th	Day	11% 5% 2 6% 5% 4 4 4 7% 8% 45%	2918
	11th to 20th	Day	5% 5% 2 6% 5% 5% 6% 4 7% 10% 46%	2940
	21st to end	Day	5% 4 1 5% 5% 5% 6% 4 7% 11% 45%	2940
July	1st to 10th	Day	9% 7% 2 7% 5% 6% 5% 4 7% 11% 38%	8280
	11th to 20th	Day	7% 5% 2 7% 5% 6% 7% 5% 9% 12% 34%	8280
	21st to end	Day	9% 6% 3 7% 5% 5% 6% 4 8% 12% 35%	8598
August	1st to 10th	Day	5% 4 1 4 4 4 5% 4 6% 10% 54%	4095
	11th to 20th	Day	8% 6% 2 6% 4 5% 6% 4 7% 10% 41%	3897
	21st to end	Day	5% 4 1 4 4 4 5% 4 6% 9% 54%	4312
September	1st to 10th	Day	11% 4 2 6% 6% 5% 4 4 6% 7% 45%	2400
	11th to 20th	Day	11% 5% 3 6% 4 4 4 4 5% 7% 47%	2215
	21st to end	Day	13% 6% 2 5% 4 4 4 3 4 7% 48%	2200
October	1st to 10th	Day	10% 4 2 4 3 3 2 3 4 7% 57%	2200
	11th to 20th	Day	12% 5% 2 5% 3 4 3 3 3 6% 54%	2078
	21st to end	Day	19% 7% 2 6% 3 3 2 3 4 6% 47%	2026
November	1st to 10th	Day	12% 5% 1 6% 3 4 3 2 5% 5% 53%	1852
	11th to 20th	Day	15% 7% 2 4 3 3 4 4 5% 6% 48%	1890
	21st to end	Day	16% 9% 3 6% 4 4 3 3 5% 4 44%	1890
December	1st to 10th	Day	16% 9% 2 6% 3 4 3 3 4 5% 44%	3020
	11th to 20th	Day	17% 12% 4 7% 5% 4 4 3 5% 5% 34%	3289
	21st to end	Day	18% 12% 5% 9% 5% 5% 5% 3 5% 7% 27%	4070
January	1st to 10th	Night	16% 11% 3 8% 4 3 3 3 4 5% 38%	8232
	11th to 20th	Night	14% 9% 3 9% 4 4 4 2 4 4 42%	8280
	21st to end	Night	19% 10% 5% 8% 4 4 3 3 4 5% 37%	8065
February	1st to 10th	Night	21% 10% 3 9% 4 4 4 3 4 5% 32%	2520
	11th to 20th	Night	21% 8% 3 8% 4 4 3 2 4 5% 36%	2458
	21st to end	Night	20% 10% 4 6% 4 4 4 3 4 5% 36%	2076
March	1st to 10th	Night	18% 10% 4 8% 4 3 3 3 5% 5% 37%	5493
	11th to 20th	Night	11% 6% 2 6% 4 4 3 3 5% 6% 49%	5405
	21st to end	Night	14% 7% 3 7% 4 4 4 3 5% 7% 41%	5133
April	1st to 10th	Night	13% 4 2 6% 4 4 4 3 5% 8% 47%	2100
	11th to 20th	Night	13% 6% 3 5% 4 3 4 3 4 7% 46%	2075
	21st to end	Night	13% 6% 3 6% 5% 4 4 4 5% 8% 41%	2088
May	1st to 10th	Night	15% 8% 3 7% 5% 4 5% 4 6% 8% 35%	5237
	11th to 20th	Night	13% 7% 2 8% 5% 5% 5% 4 6% 8% 36%	5234
	21st to end	Night	16% 9% 3 9% 5% 5% 5% 4 6% 8% 31%	5761
June	1st to 10th	Night	12% 6% 2 6% 4 3 4 4 4 9% 46%	1697
	11th to 20th	Night	5% 3 2 6% 4 4 5% 4 6% 9% 54%	1680
	21st to end	Night	4 2 1 4 4 5% 5% 4 8% 11% 52%	1680
July	1st to 10th	Night	7% 4 2 6% 5% 5% 5% 4 7% 9% 45%	4708
	11th to 20th	Night	5% 5% 2 7% 5% 5% 5% 6% 8% 12% 40%	4707
	21st to end	Night	7% 6% 2 8% 5% 5% 5% 5% 8% 13% 36%	5488
August	1st to 10th	Night	4 3 2 4 3 4 4 4 5% 7% 60%	3269
	11th to 20th	Night	3 4 2 5% 5% 4 5% 5% 8% 10% 50%	3240
	21st to end	Night	4 3 1 4 3 3 4 3 6% 8% 61%	3586
September	1st to 10th	Night	11% 5% 2 5% 3 3 4 4 5% 7% 52%	2000
	11th to 20th	Night	9% 5% 2 6% 4 3 4 4 5% 6% 53%	2165
	21st to end	Night	10% 5% 2 5% 3 3 3 3 4 7% 54%	2200
October	1st to 10th	Night	8% 5% 1 4 2 3 4 2 5% 6% 62%	2200
	11th to 20th	Night	14% 5% 2 5% 3 3 3 2 4 4 56%	2319
	21st to end	Night	15% 7% 2 6% 4 3 4 2 4 6% 47%	2811
November	1st to 10th	Night	12% 5% 2 5% 4 3 3 3 4 6% 53%	2666
	11th to 20th	Night	13% 6% 2 5% 4 3 4 3 5% 7% 49%	2730
	21st to end	Night	17% 7% 3 5% 3 3 4 3 5% 5% 46%	2730
December	1st to 10th	Night	17% 9% 3 7% 3 3 3 3 4 4 42%	4380
	11th to 20th	Night	20% 8% 2 6% 4 3 3 3 4 5% 41%	5120
	21st to end	Night	20% 12% 5% 9% 5% 5% 5% 3 4 5% 27%	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	54% 4 11% 21% 8% 1	4692
	11th to 20th	Day	40% 3 6% 29% 21% 1	4710
	21st to end	Day	49% 3 8% 21% 14% 5%	6112
February	1st to 10th	Day	49% 4 9% 23% 13% 2	2100
	11th to 20th	Day	51% 5% 7% 20% 13% 4	2058
	21st to end	Day	49% 4 8% 19% 14% 5%	1730
March	1st to 10th	Day	51% 4 4 18% 17% 6%	4580
	11th to 20th	Day	39% 4 8% 25% 20% 5%	4761
	21st to end	Day	41% 5% 9% 28% 16% 1	6071
April	1st to 10th	Day	40% 5% 11% 22% 20% 2	2520
	11th to 20th	Day	43% 5% 9% 21% 18% 4	2494
	21st to end	Day	42% 5% 10% 27% 14% 2	2530
May	1st to 10th	Day	48% 7% 12% 22% 10% 1	7651
	11th to 20th	Day	45% 7% 12% 21% 14% 2	7630
	21st to end	Day	51% 7% 10% 17% 13% 2	8405
June	1st to 10th	Day	35% 7% 12% 23% 19% 3	2918
	11th to 20th	Day	31% 9% 15% 25% 18% 3	2940
	21st to end	Day	30% 9% 16% 24% 16% 4	2940
July	1st to 10th	Day	39% 8% 14% 26% 11% 1	8211
	11th to 20th	Day	36% 12% 18% 26% 6% 1	8205
	21st to end	Day	38% 8% 22% 24% 7% 1	8410
August	1st to 10th	Day	24% 8% 15% 31% 22% 1	4082
	11th to 20th	Day	35% 8% 12% 26% 17% 1	3933
	21st to end	Day	25% 8% 10% 32% 22% 2	4311
September	1st to 10th	Day	36% 8% 11% 23% 19% 4	2400
	11th to 20th	Day	36% 6% 10% 23% 23% 3	2215
	21st to end	Day	35% 6% 8% 23% 22% 6%	2200
October	1st to 10th	Day	19% 3 6% 18% 46% 9%	3590
	11th to 20th	Day	23% 3 7% 27% 30% 11%	3357
	21st to end	Day	30% 3 6% 26% 28% 7%	3251
November	1st to 10th	Day	33% 5% 9% 23% 25% 5%	1852
	11th to 20th	Day	37% 4 8% 23% 22% 6%	1890
	21st to end	Day	44% 3 7% 25% 17% 4	1890
December	1st to 10th	Day	43% 4 7% 28% 18% 1	3020
	11th to 20th	Day	52% 5% 8% 19% 14% 2	3286
	21st to end	Day	56% 5% 12% 19% 7%	4070
January	1st to 10th	Night	48% 3 12% 25% 11% 1	8233
	11th to 20th	Night	45% 4 6% 21% 21% 3	8280
	21st to end	Night	51% 3 8% 20% 14% 4	8065
February	1st to 10th	Night	55% 4 9% 17% 13% 1	2520
	11th to 20th	Night	52% 4 6% 21% 14% 4	2459
	21st to end	Night	51% 5% 8% 17% 17% 3	2076
March	1st to 10th	Night	49% 4 6% 16% 18% 6%	5493
	11th to 20th	Night	36% 4 8% 22% 19% 11%	5405
	21st to end	Night	43% 5% 10% 25% 15% 2	5133
April	1st to 10th	Night	36% 5% 12% 25% 19% 3	2100
	11th to 20th	Night	37% 5% 11% 20% 21% 6%	2075
	21st to end	Night	41% 5% 10% 25% 18% 2	2088
May	1st to 10th	Night	46% 7% 12% 23% 11% 1	5264
	11th to 20th	Night	44% 8% 13% 19% 15% 1	5235
	21st to end	Night	49% 8% 12% 19% 11% 1	5771
June	1st to 10th	Night	36% 5% 11% 24% 20% 3	1697
	11th to 20th	Night	25% 8% 16% 25% 23% 3	1680
	21st to end	Night	25% 8% 16% 28% 17% 5%	1680
July	1st to 10th	Night	34% 9% 15% 27% 14% 1	4670
	11th to 20th	Night	33% 12% 21% 25% 9% 1	4662
	21st to end	Night	38% 9% 21% 24% 8% 1	5363
August	1st to 10th	Night	22% 7% 13% 36% 22% 1	3258
	11th to 20th	Night	25% 8% 19% 29% 18% 1	3270
	21st to end	Night	21% 6% 11% 34% 26% 3	3586
September	1st to 10th	Night	31% 6% 11% 25% 22% 5%	2000
	11th to 20th	Night	31% 6% 8% 26% 25% 4	2165
	21st to end	Night	31% 5% 9% 22% 26% 7%	2200
October	1st to 10th	Night	17% 3 6% 17% 46% 11%	3590
	11th to 20th	Night	21% 2 5% 22% 38% 11%	3766
	21st to end	Night	29% 3 7% 23% 27% 11%	4536
November	1st to 10th	Night	34% 3 7% 25% 25% 6%	2666
	11th to 20th	Night	35% 4 6% 25% 22% 8%	2730
	21st to end	Night	40% 4 8% 25% 19% 4	2730
December	1st to 10th	Night	46% 4 8% 22% 19% 1	4380
	11th to 20th	Night	45% 3 9% 23% 18% 2	5122
	21st to end	Night	59% 5% 8% 18% 8% 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	25% 22% 32% 16% 5%	330
	11th to 20th	Day	22% 27% 35% 14% 2	330
	21st to end	Day	20% 23% 43% 11% 2	363
February	1st to 10th	Day	26% 18% 36% 16% 3 1	330
	11th to 20th	Day	29% 24% 36% 9% 2	330
	21st to end	Day	27% 23% 35% 12% 3	273
March	1st to 10th	Day	25% 20% 36% 14% 4 1	330
	11th to 20th	Day	22% 20% 39% 13% 4 1	393
	21st to end	Day	23% 18% 36% 17% 5% 1	594
April	1st to 10th	Day	21% 16% 31% 24% 7% 1	540
	11th to 20th	Day	22% 16% 27% 23% 11% 1	532
	21st to end	Day	19% 14% 32% 23% 9% 3	540
May	1st to 10th	Day	21% 15% 28% 25% 8% 3	543
	11th to 20th	Day	16% 9% 25% 31% 14% 5%	567
	21st to end	Day	13% 7% 21% 29% 17% 12%	617
June	1st to 10th	Day	11% 5% 19% 27% 25% 12%	758
	11th to 20th	Day	6% 4 19% 32% 28% 11%	780
	21st to end	Day	5% 4 18% 33% 25% 14%	780
July	1st to 10th	Day	10% 2 12% 24% 29% 21%	771
	11th to 20th	Day	8% 4 13% 27% 32% 16%	768
	21st to end	Day	8% 2 15% 29% 28% 18%	713
August	1st to 10th	Day	10% 2 13% 28% 31% 16%	566
	11th to 20th	Day	11% 1 13% 32% 31% 11%	535
	21st to end	Day	9% 2 9% 22% 37% 20%	583
September	1st to 10th	Day	11% 2 14% 28% 33% 13%	530
	11th to 20th	Day	9% 2 10% 25% 37% 17%	530
	21st to end	Day	17% 6% 18% 28% 21% 10%	530
October	1st to 10th	Day	9% 5% 18% 35% 25% 8%	530
	11th to 20th	Day	12% 13% 26% 29% 15% 5%	408
	21st to end	Day	26% 14% 26% 25% 8% 1	363
November	1st to 10th	Day	18% 9% 38% 22% 12% 2	330
	11th to 20th	Day	16% 20% 32% 25% 6% 1	330
	21st to end	Day	22% 14% 34% 19% 9% 2	330
December	1st to 10th	Day	26% 16% 33% 18% 8%	330
	11th to 20th	Day	22% 17% 35% 21% 5%	330
	21st to end	Day	28% 17% 36% 17% 2	363
January	1st to 10th	Night	25% 14% 32% 26% 3	1050
	11th to 20th	Night	26% 14% 35% 21% 4	1050
	21st to end	Night	22% 13% 39% 23% 2	1030
February	1st to 10th	Night	25% 14% 34% 24% 2	840
	11th to 20th	Night	27% 14% 37% 21% 2	823
	21st to end	Night	27% 13% 35% 22% 2	692
March	1st to 10th	Night	21% 15% 32% 27% 4	840
	11th to 20th	Night	20% 13% 36% 25% 5% 1	840
	21st to end	Night	19% 12% 34% 27% 7% 1	728
April	1st to 10th	Night	17% 11% 33% 31% 7%	630
	11th to 20th	Night	17% 11% 32% 28% 12%	623
	21st to end	Night	16% 9% 31% 33% 10% 1	630
May	1st to 10th	Night	18% 7% 31% 28% 14% 2	630
	11th to 20th	Night	13% 6% 22% 37% 19% 2	621
	21st to end	Night	11% 2 17% 39% 27% 4	683
June	1st to 10th	Night	14% 3 13% 38% 29% 3	630
	11th to 20th	Night	5% 3 14% 41% 34% 3	630
	21st to end	Night	4 1 13% 40% 36% 6%	630
July	1st to 10th	Night	8% 3 7% 29% 44% 10%	615
	11th to 20th	Night	7% 3 8% 27% 48% 6%	612
	21st to end	Night	7% 2 11% 34% 37% 8%	690
August	1st to 10th	Night	6% 1 8% 32% 45% 7%	627
	11th to 20th	Night	5% 1 10% 41% 38% 4	606
	21st to end	Night	7% 1 8% 32% 44% 8%	660
September	1st to 10th	Night	12% 2 12% 33% 37% 5%	600
	11th to 20th	Night	11% 2 10% 31% 40% 6%	765
	21st to end	Night	12% 3 19% 32% 30% 4	800
October	1st to 10th	Night	10% 4 18% 34% 29% 5%	800
	11th to 20th	Night	17% 5% 24% 35% 17% 2	800
	21st to end	Night	19% 8% 30% 28% 14% 1	880
November	1st to 10th	Night	14% 8% 27% 35% 14% 1	820
	11th to 20th	Night	15% 10% 34% 30% 10%	840
	21st to end	Night	22% 11% 29% 28% 11%	840
December	1st to 10th	Night	24% 11% 30% 29% 5%	840
	11th to 20th	Night	24% 10% 32% 28% 6% 1	919
	21st to end	Night	30% 11% 30% 26% 4	1155

Page generated at 2026-08-12 02:37:16. Version ac07

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