Murfreesboro
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Murfreesboro clear sky chart from 2005-11-06 to 2026-10-29.

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	12% 7% 3 7% 5% 5% 5% 4 6% 8% 38%	149948
	Night	13% 8% 3 7% 4 4 4 3 5% 7% 41%	142185
Transparency	Day	42% 7% 11% 22% 15% 3	153642
	Night	40% 6% 11% 21% 18% 4	146553
Seeing	Day	16% 12% 23% 23% 18% 8%	17694
	Night	16% 9% 24% 29% 18% 3	27086

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	16% 11% 5% 10% 5% 4 5% 4 5% 5% 30%	5258
	11th to 20th	Day	14% 8% 4 10% 4 4 4 2 3 4 44%	5280
	21st to end	Day	21% 8% 5% 8% 4 4 4 3 5% 6% 33%	6293
February	1st to 10th	Day	19% 11% 4 8% 5% 4 4 2 4 5% 35%	2100
	11th to 20th	Day	20% 12% 4 8% 4 4 3 3 4 5% 32%	2048
	21st to end	Day	19% 9% 3 6% 5% 3 4 2 5% 5% 37%	1730
March	1st to 10th	Day	16% 11% 3 8% 5% 4 4 3 5% 5% 34%	4580
	11th to 20th	Day	12% 8% 2 7% 4 4 4 3 4 5% 47%	4918
	21st to end	Day	12% 7% 3 7% 5% 4 5% 4 5% 7% 42%	5812
April	1st to 10th	Day	12% 6% 2 5% 4 5% 4 4 6% 7% 45%	2520
	11th to 20th	Day	13% 7% 2 6% 4 4 4 3 5% 6% 46%	2494
	21st to end	Day	12% 8% 2 7% 5% 5% 5% 3 5% 7% 40%	2582
May	1st to 10th	Day	17% 8% 3 7% 5% 5% 5% 4 7% 8% 33%	7616
	11th to 20th	Day	12% 8% 4 9% 6% 5% 5% 4 5% 7% 35%	7626
	21st to end	Day	17% 10% 4 9% 6% 5% 5% 4 5% 6% 30%	8391
June	1st to 10th	Day	8% 7% 2 6% 5% 5% 5% 5% 7% 8% 40%	2730
	11th to 20th	Day	5% 4 2 5% 5% 6% 6% 5% 7% 10% 45%	2829
	21st to end	Day	5% 5% 2 7% 5% 5% 6% 5% 7% 12% 41%	2940
July	1st to 10th	Day	6% 6% 2 7% 6% 6% 7% 5% 8% 11% 36%	8280
	11th to 20th	Day	7% 6% 2 9% 7% 7% 7% 6% 10% 12% 27%	7805
	21st to end	Day	10% 7% 3 7% 6% 6% 6% 6% 8% 12% 30%	8340
August	1st to 10th	Day	5% 5% 2 7% 6% 6% 7% 5% 9% 11% 37%	5782
	11th to 20th	Day	5% 4 2 5% 4 5% 6% 5% 8% 11% 45%	5486
	21st to end	Day	5% 4 2 4 3 4 5% 4 6% 8% 55%	6080
September	1st to 10th	Day	11% 6% 2 7% 6% 5% 6% 5% 5% 7% 40%	2465
	11th to 20th	Day	12% 6% 2 7% 4 4 5% 4 5% 6% 44%	2310
	21st to end	Day	11% 6% 2 6% 4 4 4 3 6% 7% 47%	2310
October	1st to 10th	Day	11% 5% 2 5% 3 3 4 3 4 5% 55%	2310
	11th to 20th	Day	11% 4 2 5% 3 3 3 3 4 7% 55%	2301
	21st to end	Day	15% 6% 2 6% 4 3 4 3 5% 6% 46%	2052
November	1st to 10th	Day	12% 6% 2 4 3 3 4 3 4 6% 55%	1852
	11th to 20th	Day	13% 7% 2 5% 4 3 3 3 5% 7% 48%	1890
	21st to end	Day	14% 8% 3 6% 3 3 4 4 5% 5% 43%	1890
December	1st to 10th	Day	13% 8% 3 7% 4 4 4 4 5% 5% 42%	3020
	11th to 20th	Day	17% 11% 4 11% 5% 5% 4 3 3 4 32%	3463
	21st to end	Day	16% 11% 5% 9% 5% 5% 5% 4 6% 8% 28%	4565
January	1st to 10th	Night	15% 10% 3 9% 4 3 4 3 4 6% 39%	7635
	11th to 20th	Night	16% 8% 3 7% 4 4 3 2 3 4 45%	7680
	21st to end	Night	18% 11% 4 8% 4 4 3 3 3 4 38%	7884
February	1st to 10th	Night	19% 10% 3 8% 4 4 3 3 5% 6% 34%	2520
	11th to 20th	Night	22% 10% 4 6% 5% 4 4 2 4 4 35%	2458
	21st to end	Night	22% 10% 2 6% 4 4 4 3 5% 5% 35%	2076
March	1st to 10th	Night	19% 10% 3 7% 5% 4 4 3 5% 7% 33%	5493
	11th to 20th	Night	11% 6% 2 5% 3 4 4 3 6% 6% 49%	5260
	21st to end	Night	13% 7% 2 7% 5% 5% 4 3 5% 6% 42%	5401
April	1st to 10th	Night	12% 4 2 6% 4 4 4 3 6% 8% 47%	2100
	11th to 20th	Night	14% 6% 2 4 3 3 3 4 5% 7% 49%	2075
	21st to end	Night	12% 6% 2 7% 5% 4 4 4 5% 7% 45%	2037
May	1st to 10th	Night	14% 9% 3 8% 5% 5% 4 4 6% 8% 34%	5237
	11th to 20th	Night	12% 8% 3 8% 6% 5% 5% 4 6% 8% 36%	5234
	21st to end	Night	14% 9% 3 10% 6% 6% 6% 4 6% 7% 29%	5761
June	1st to 10th	Night	6% 6% 3 7% 5% 5% 5% 4 6% 10% 44%	1890
	11th to 20th	Night	3 3 1 5% 4 4 5% 4 8% 10% 52%	1781
	21st to end	Night	5% 4 1 6% 4 4 5% 5% 6% 11% 49%	1680
July	1st to 10th	Night	6% 5% 2 6% 5% 5% 5% 5% 8% 12% 40%	4708
	11th to 20th	Night	7% 6% 2 9% 6% 6% 6% 5% 9% 13% 31%	5140
	21st to end	Night	8% 7% 3 8% 6% 5% 6% 5% 8% 12% 32%	5736
August	1st to 10th	Night	5% 5% 2 6% 5% 5% 5% 4 7% 10% 46%	4362
	11th to 20th	Night	4 3 1 4 3 4 5% 5% 8% 12% 51%	4560
	21st to end	Night	4 3 1 5% 3 4 5% 3 6% 9% 55%	5046
September	1st to 10th	Night	9% 5% 3 6% 4 4 5% 4 5% 7% 48%	2132
	11th to 20th	Night	10% 5% 2 7% 4 5% 4 4 4 8% 46%	2310
	21st to end	Night	11% 5% 2 5% 4 4 4 3 5% 7% 50%	2310
October	1st to 10th	Night	10% 4 1 4 3 3 3 3 4 6% 58%	2310
	11th to 20th	Night	14% 5% 2 5% 3 4 3 3 4 6% 53%	2313
	21st to end	Night	14% 7% 2 5% 3 3 3 3 4 6% 50%	2965
November	1st to 10th	Night	12% 5% 2 6% 4 3 3 3 4 5% 53%	2666
	11th to 20th	Night	12% 7% 2 5% 3 3 3 2 5% 7% 50%	2730
	21st to end	Night	15% 8% 4 5% 4 3 4 3 5% 5% 44%	2730
December	1st to 10th	Night	18% 10% 3 8% 4 3 3 3 4 4 40%	4380
	11th to 20th	Night	20% 10% 3 6% 4 3 3 2 4 4 40%	4952
	21st to end	Night	15% 12% 4 9% 5% 5% 5% 4 5% 6% 30%	6633

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	55% 4 11% 19% 9% 1	5259
	11th to 20th	Day	46% 3 5% 19% 27% 1	5280
	21st to end	Day	52% 4 8% 20% 12% 4	6293
February	1st to 10th	Day	53% 5% 7% 19% 14% 2	2100
	11th to 20th	Day	55% 3 7% 18% 13% 3	2058
	21st to end	Day	50% 4 8% 16% 17% 5%	1730
March	1st to 10th	Day	51% 5% 7% 13% 15% 9%	4580
	11th to 20th	Day	40% 4 7% 21% 20% 8%	4918
	21st to end	Day	41% 5% 9% 28% 16% 1	5814
April	1st to 10th	Day	37% 7% 11% 24% 18% 3	2520
	11th to 20th	Day	38% 6% 8% 22% 22% 5%	2494
	21st to end	Day	42% 6% 10% 25% 16% 2	2582
May	1st to 10th	Day	47% 7% 13% 21% 11% 1	7651
	11th to 20th	Day	46% 7% 12% 21% 13% 1	7630
	21st to end	Day	55% 7% 8% 16% 12% 2	8405
June	1st to 10th	Day	38% 10% 11% 22% 17% 2	2730
	11th to 20th	Day	32% 9% 17% 23% 17% 2	2829
	21st to end	Day	33% 10% 17% 21% 15% 3	2940
July	1st to 10th	Day	38% 11% 18% 25% 8% 1	8211
	11th to 20th	Day	43% 12% 20% 19% 4 1	7733
	21st to end	Day	44% 10% 20% 20% 6% 1	8156
August	1st to 10th	Day	35% 10% 16% 26% 13% 1	5769
	11th to 20th	Day	29% 8% 18% 29% 14% 1	5522
	21st to end	Day	26% 6% 11% 33% 23% 2	6079
September	1st to 10th	Day	40% 8% 11% 19% 17% 4	2465
	11th to 20th	Day	38% 7% 10% 24% 18% 2	2310
	21st to end	Day	36% 6% 12% 21% 21% 5%	2310
October	1st to 10th	Day	25% 4 5% 17% 38% 10%	3700
	11th to 20th	Day	23% 3 6% 23% 32% 14%	3645
	21st to end	Day	30% 4 7% 23% 28% 8%	3252
November	1st to 10th	Day	31% 5% 9% 22% 28% 5%	1852
	11th to 20th	Day	36% 4 7% 23% 24% 5%	1890
	21st to end	Day	41% 5% 6% 24% 20% 4	1890
December	1st to 10th	Day	44% 5% 5% 26% 20% 1	3020
	11th to 20th	Day	56% 4 8% 17% 12% 3	3460
	21st to end	Day	52% 6% 11% 22% 7% 2	4565
January	1st to 10th	Night	46% 3 15% 21% 13% 1	7636
	11th to 20th	Night	44% 4 5% 18% 25% 4	7680
	21st to end	Night	52% 3 8% 17% 16% 5%	7884
February	1st to 10th	Night	51% 4 10% 18% 15% 1	2520
	11th to 20th	Night	55% 3 7% 18% 14% 4	2459
	21st to end	Night	51% 4 8% 15% 17% 5%	2076
March	1st to 10th	Night	50% 5% 7% 14% 18% 5%	5493
	11th to 20th	Night	36% 4 7% 21% 20% 13%	5260
	21st to end	Night	43% 4 9% 26% 16% 2	5401
April	1st to 10th	Night	35% 5% 13% 23% 21% 3	2100
	11th to 20th	Night	34% 5% 9% 22% 22% 7%	2075
	21st to end	Night	38% 6% 11% 26% 18% 2	2037
May	1st to 10th	Night	47% 7% 11% 22% 12% 1	5264
	11th to 20th	Night	45% 8% 13% 17% 15% 2	5235
	21st to end	Night	51% 9% 11% 17% 11% 1	5771
June	1st to 10th	Night	36% 6% 13% 26% 16% 3	1890
	11th to 20th	Night	24% 8% 17% 31% 17% 3	1781
	21st to end	Night	28% 10% 17% 27% 15% 4	1680
July	1st to 10th	Night	34% 10% 21% 24% 9% 1	4670
	11th to 20th	Night	40% 12% 22% 20% 4 2	5092
	21st to end	Night	42% 10% 24% 17% 7%	5606
August	1st to 10th	Night	30% 8% 15% 29% 16% 1	4351
	11th to 20th	Night	23% 8% 21% 33% 14% 1	4590
	21st to end	Night	24% 7% 11% 33% 22% 2	5046
September	1st to 10th	Night	34% 8% 12% 23% 19% 5%	2132
	11th to 20th	Night	36% 6% 12% 20% 24% 2	2310
	21st to end	Night	33% 6% 10% 22% 23% 6%	2310
October	1st to 10th	Night	24% 5% 6% 19% 35% 12%	3700
	11th to 20th	Night	22% 3 5% 22% 31% 18%	3696
	21st to end	Night	25% 3 6% 24% 31% 11%	4715
November	1st to 10th	Night	35% 4 9% 21% 25% 7%	2666
	11th to 20th	Night	34% 3 8% 21% 26% 7%	2730
	21st to end	Night	42% 4 6% 23% 19% 5%	2730
December	1st to 10th	Night	49% 4 6% 17% 23% 2	4380
	11th to 20th	Night	48% 3 6% 21% 20% 2	4954
	21st to end	Night	54% 5% 10% 21% 10% 1	6633

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% 23% 33% 14% 5%	330
	11th to 20th	Day	28% 27% 28% 12% 3 1	330
	21st to end	Day	25% 25% 37% 11% 2	363
February	1st to 10th	Day	29% 19% 36% 13% 2 1	330
	11th to 20th	Day	35% 25% 28% 9% 1 1	330
	21st to end	Day	33% 25% 28% 11% 4	273
March	1st to 10th	Day	25% 22% 35% 14% 4	330
	11th to 20th	Day	24% 22% 33% 15% 6%	459
	21st to end	Day	24% 18% 35% 16% 6%	594
April	1st to 10th	Day	20% 18% 28% 24% 9% 1	540
	11th to 20th	Day	17% 17% 32% 22% 10% 2	532
	21st to end	Day	18% 18% 28% 22% 11% 3	540
May	1st to 10th	Day	19% 14% 29% 22% 12% 3	543
	11th to 20th	Day	14% 11% 27% 27% 14% 7%	567
	21st to end	Day	16% 7% 21% 27% 18% 12%	617
June	1st to 10th	Day	11% 6% 22% 25% 23% 13%	570
	11th to 20th	Day	6% 4 19% 29% 28% 14%	669
	21st to end	Day	5% 4 20% 29% 26% 16%	780
July	1st to 10th	Day	9% 3 12% 29% 27% 20%	771
	11th to 20th	Day	9% 4 11% 24% 32% 21%	608
	21st to end	Day	9% 3 13% 28% 30% 18%	620
August	1st to 10th	Day	11% 3 12% 25% 33% 16%	566
	11th to 20th	Day	8% 3 13% 30% 33% 13%	559
	21st to end	Day	12% 2 9% 24% 34% 19%	627
September	1st to 10th	Day	12% 2 13% 26% 32% 15%	570
	11th to 20th	Day	11% 5% 10% 25% 32% 18%	570
	21st to end	Day	15% 7% 15% 29% 26% 8%	570
October	1st to 10th	Day	13% 4 21% 26% 28% 7%	570
	11th to 20th	Day	13% 12% 26% 26% 19% 4	566
	21st to end	Day	21% 13% 27% 26% 10% 3	387
November	1st to 10th	Day	19% 10% 32% 27% 10% 2	330
	11th to 20th	Day	16% 15% 39% 24% 6%	330
	21st to end	Day	19% 22% 29% 17% 12% 2	330
December	1st to 10th	Day	27% 20% 31% 19% 3	330
	11th to 20th	Day	23% 21% 31% 16% 8% 1	330
	21st to end	Day	23% 27% 30% 17% 4	363
January	1st to 10th	Night	24% 16% 32% 25% 4	840
	11th to 20th	Night	26% 20% 31% 19% 3	840
	21st to end	Night	21% 16% 37% 23% 2	924
February	1st to 10th	Night	25% 14% 34% 24% 3	840
	11th to 20th	Night	30% 16% 30% 21% 2	823
	21st to end	Night	30% 16% 32% 20% 2	692
March	1st to 10th	Night	21% 16% 34% 24% 4	840
	11th to 20th	Night	22% 16% 35% 21% 6% 1	840
	21st to end	Night	18% 15% 34% 26% 7%	840
April	1st to 10th	Night	15% 13% 33% 30% 8%	630
	11th to 20th	Night	17% 11% 32% 30% 9% 1	623
	21st to end	Night	16% 9% 31% 31% 11% 2	630
May	1st to 10th	Night	13% 8% 33% 27% 17% 1	630
	11th to 20th	Night	11% 7% 25% 34% 18% 4	621
	21st to end	Night	9% 3 20% 37% 25% 5%	683
June	1st to 10th	Night	8% 4 18% 38% 28% 5%	630
	11th to 20th	Night	5% 2 13% 39% 34% 7%	630
	21st to end	Night	5% 1 13% 36% 37% 8%	630
July	1st to 10th	Night	10% 2 9% 30% 40% 9%	615
	11th to 20th	Night	6% 3 10% 28% 42% 11%	612
	21st to end	Night	8% 1 10% 31% 41% 9%	690
August	1st to 10th	Night	8% 2 5% 31% 44% 9%	627
	11th to 20th	Night	7% 3 9% 36% 39% 5%	624
	21st to end	Night	8% 2 8% 33% 40% 8%	693
September	1st to 10th	Night	9% 3 10% 32% 39% 7%	662
	11th to 20th	Night	11% 4 13% 29% 38% 5%	840
	21st to end	Night	13% 3 15% 31% 35% 3	840
October	1st to 10th	Night	10% 6% 17% 33% 29% 5%	840
	11th to 20th	Night	17% 7% 23% 34% 18% 1	840
	21st to end	Night	17% 9% 26% 31% 16% 2	913
November	1st to 10th	Night	15% 8% 22% 37% 16% 2	820
	11th to 20th	Night	15% 12% 33% 28% 11% 1	840
	21st to end	Night	19% 13% 30% 27% 11% 1	840
December	1st to 10th	Night	26% 14% 30% 26% 5%	840
	11th to 20th	Night	23% 12% 31% 28% 6%	840
	21st to end	Night	26% 16% 29% 24% 4	924

Page generated at 2026-10-26 03:37:52. Version ac07

Copyright © 2026 Attilla Danko.