Cashville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cashville clear sky chart from 2005-11-06 to 2026-05-02.

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% 6% 2 6% 4 4 4 4 6% 8% 44%	131546
	Night	13% 7% 3 6% 4 4 4 4 5% 7% 43%	130931
Transparency	Day	36% 8% 14% 23% 16% 3	135135
	Night	39% 6% 12% 23% 16% 3	135412
Seeing	Day	15% 7% 20% 28% 23% 7%	17105
	Night	16% 8% 25% 31% 18% 3	26681

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	12% 5% 3 6% 3 3 4 3 5% 6% 51%	4679
	11th to 20th	Day	12% 6% 3 7% 4 3 3 3 3 4 52%	5280
	21st to end	Day	12% 7% 3 8% 5% 4 5% 4 4 6% 43%	5780
February	1st to 10th	Day	13% 9% 2 6% 5% 4 4 5% 7% 7% 39%	1890
	11th to 20th	Day	20% 7% 3 5% 3 3 4 3 5% 5% 42%	2027
	21st to end	Day	17% 8% 3 7% 5% 4 4 3 5% 5% 40%	1730
March	1st to 10th	Day	17% 8% 2 6% 4 4 4 3 5% 7% 40%	4738
	11th to 20th	Day	10% 5% 2 5% 4 3 3 3 5% 7% 52%	5090
	21st to end	Day	13% 7% 2 6% 4 4 4 3 5% 7% 45%	5837
April	1st to 10th	Day	11% 5% 2 5% 3 4 3 4 5% 8% 48%	2520
	11th to 20th	Day	10% 5% 2 4 4 3 4 4 6% 8% 50%	2494
	21st to end	Day	12% 6% 2 4 4 3 4 4 5% 7% 48%	2520
May	1st to 10th	Day	14% 8% 2 6% 4 4 5% 4 6% 9% 37%	5417
	11th to 20th	Day	18% 8% 3 7% 4 4 4 4 6% 9% 33%	6237
	21st to end	Day	13% 5% 2 5% 4 4 4 4 6% 10% 42%	6934
June	1st to 10th	Day	10% 5% 2 5% 4 4 4 4 7% 10% 45%	2800
	11th to 20th	Day	9% 5% 2 4 3 4 4 5% 7% 11% 46%	2800
	21st to end	Day	6% 5% 2 5% 5% 4 5% 4 7% 11% 47%	2800
July	1st to 10th	Day	7% 5% 2 5% 4 4 5% 4 8% 12% 45%	6360
	11th to 20th	Day	10% 6% 3 7% 5% 5% 6% 5% 8% 11% 34%	6282
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 8% 12% 40%	6424
August	1st to 10th	Day	14% 8% 2 7% 4 5% 4 5% 8% 10% 33%	4177
	11th to 20th	Day	9% 6% 3 6% 5% 6% 5% 4 6% 10% 39%	3850
	21st to end	Day	9% 4 2 5% 4 4 4 3 7% 11% 47%	4312
September	1st to 10th	Day	15% 5% 2 5% 4 4 4 3 6% 8% 44%	2400
	11th to 20th	Day	11% 6% 3 6% 4 3 5% 4 5% 7% 45%	2391
	21st to end	Day	19% 8% 3 6% 4 4 3 3 5% 7% 37%	2170
October	1st to 10th	Day	13% 6% 2 6% 5% 4 4 3 5% 6% 47%	2000
	11th to 20th	Day	15% 6% 2 5% 3 3 3 3 4 5% 52%	2000
	21st to end	Day	12% 7% 2 6% 5% 4 4 3 4 6% 48%	2200
November	1st to 10th	Day	13% 6% 3 5% 3 3 3 3 5% 7% 49%	1886
	11th to 20th	Day	12% 7% 2 6% 5% 3 4 4 4 7% 47%	1890
	21st to end	Day	15% 5% 2 5% 4 4 4 3 4 6% 48%	1833
December	1st to 10th	Day	11% 8% 3 6% 3 4 3 3 5% 5% 48%	2680
	11th to 20th	Day	17% 9% 3 7% 3 3 2 2 3 5% 45%	3070
	21st to end	Day	12% 7% 2 5% 4 4 4 3 6% 8% 46%	4048
January	1st to 10th	Night	11% 7% 3 6% 4 4 5% 4 4 7% 45%	8196
	11th to 20th	Night	13% 7% 3 7% 3 3 3 2 3 5% 51%	7680
	21st to end	Night	14% 7% 2 8% 4 4 4 3 4 5% 45%	8401
February	1st to 10th	Night	16% 8% 3 6% 4 3 3 3 5% 6% 43%	2730
	11th to 20th	Night	20% 8% 2 5% 4 4 3 3 5% 5% 40%	2477
	21st to end	Night	17% 7% 3 5% 3 3 4 3 4 5% 45%	2076
March	1st to 10th	Night	18% 8% 2 5% 3 3 4 3 4 6% 44%	5317
	11th to 20th	Night	12% 7% 3 6% 4 4 4 3 4 6% 47%	5090
	21st to end	Night	15% 8% 2 6% 3 3 4 3 4 6% 45%	5336
April	1st to 10th	Night	14% 7% 2 6% 5% 4 4 4 6% 7% 40%	2100
	11th to 20th	Night	11% 5% 2 4 4 4 3 3 5% 6% 52%	2075
	21st to end	Night	12% 6% 2 6% 4 5% 4 3 5% 9% 44%	2100
May	1st to 10th	Night	14% 8% 3 9% 5% 5% 5% 5% 6% 9% 32%	4501
	11th to 20th	Night	18% 9% 3 8% 5% 4 5% 4 6% 7% 33%	3698
	21st to end	Night	15% 8% 3 8% 5% 4 4 4 6% 7% 36%	3920
June	1st to 10th	Night	11% 7% 3 7% 5% 4 5% 4 7% 9% 39%	1600
	11th to 20th	Night	9% 6% 2 6% 5% 5% 6% 5% 8% 10% 40%	1600
	21st to end	Night	8% 6% 1 5% 4 5% 5% 5% 7% 10% 45%	1600
July	1st to 10th	Night	9% 5% 2 7% 5% 6% 6% 5% 8% 11% 37%	3598
	11th to 20th	Night	9% 7% 3 8% 5% 5% 6% 5% 8% 12% 32%	3657
	21st to end	Night	9% 7% 3 7% 5% 5% 5% 5% 7% 9% 38%	4427
August	1st to 10th	Night	15% 9% 3 8% 5% 4 4 4 7% 9% 31%	2938
	11th to 20th	Night	9% 7% 3 8% 5% 5% 5% 4 6% 9% 40%	3197
	21st to end	Night	8% 5% 2 6% 5% 4 4 4 5% 10% 48%	3586
September	1st to 10th	Night	11% 6% 2 6% 4 4 4 4 5% 7% 47%	2000
	11th to 20th	Night	11% 5% 3 7% 4 4 5% 3 6% 7% 46%	2007
	21st to end	Night	18% 8% 3 7% 4 6% 5% 4 5% 8% 34%	2227
October	1st to 10th	Night	13% 6% 2 4 4 3 4 3 5% 7% 48%	2400
	11th to 20th	Night	17% 5% 1 6% 4 3 3 3 4 6% 48%	2400
	21st to end	Night	15% 7% 3 5% 3 3 3 3 4 6% 48%	2640
November	1st to 10th	Night	13% 7% 2 6% 3 3 4 3 4 6% 48%	2629
	11th to 20th	Night	15% 8% 2 6% 4 4 3 4 5% 6% 43%	2730
	21st to end	Night	12% 5% 2 6% 4 3 4 3 5% 7% 49%	2783
December	1st to 10th	Night	10% 6% 2 5% 4 4 4 3 6% 6% 49%	4720
	11th to 20th	Night	17% 9% 3 7% 5% 4 5% 3 5% 6% 37%	5345
	21st to end	Night	11% 8% 3 7% 4 3 4 3 5% 7% 44%	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	34% 5% 12% 26% 19% 4	4680
	11th to 20th	Day	36% 3 6% 21% 28% 6%	5280
	21st to end	Day	41% 5% 9% 29% 14% 2	5780
February	1st to 10th	Day	41% 6% 12% 24% 13% 3	1890
	11th to 20th	Day	44% 4 9% 21% 17% 5%	2036
	21st to end	Day	46% 5% 10% 20% 15% 4	1730
March	1st to 10th	Day	42% 5% 10% 19% 18% 5%	4738
	11th to 20th	Day	31% 5% 11% 23% 22% 7%	5090
	21st to end	Day	38% 6% 12% 19% 19% 6%	5837
April	1st to 10th	Day	34% 7% 13% 22% 20% 5%	2520
	11th to 20th	Day	32% 6% 12% 25% 20% 5%	2494
	21st to end	Day	35% 6% 13% 25% 18% 4	2520
May	1st to 10th	Day	43% 12% 16% 19% 10% 1	5449
	11th to 20th	Day	45% 9% 14% 23% 8% 1	6241
	21st to end	Day	37% 11% 15% 23% 12% 2	6949
June	1st to 10th	Day	32% 10% 16% 26% 14% 2	2800
	11th to 20th	Day	32% 8% 17% 28% 14% 2	2800
	21st to end	Day	30% 9% 17% 26% 17% 1	2800
July	1st to 10th	Day	30% 10% 23% 22% 13% 2	6290
	11th to 20th	Day	41% 13% 24% 18% 4 1	6207
	21st to end	Day	32% 11% 17% 23% 16%	6240
August	1st to 10th	Day	42% 9% 19% 24% 6%	4164
	11th to 20th	Day	36% 10% 16% 28% 10%	3886
	21st to end	Day	29% 8% 14% 29% 18% 2	4312
September	1st to 10th	Day	37% 7% 16% 20% 17% 3	2400
	11th to 20th	Day	38% 7% 11% 24% 19% 1	2391
	21st to end	Day	46% 7% 9% 20% 16% 2	2170
October	1st to 10th	Day	30% 7% 11% 24% 23% 5%	3260
	11th to 20th	Day	26% 4 8% 22% 32% 8%	3240
	21st to end	Day	25% 4 10% 28% 25% 8%	3538
November	1st to 10th	Day	36% 6% 10% 27% 17% 4	1886
	11th to 20th	Day	37% 6% 13% 20% 20% 4	1890
	21st to end	Day	37% 6% 9% 27% 19% 3	1833
December	1st to 10th	Day	37% 6% 11% 29% 16% 2	2680
	11th to 20th	Day	43% 4 13% 21% 15% 3	3066
	21st to end	Day	35% 6% 14% 28% 15% 1	4048
January	1st to 10th	Night	38% 4 12% 24% 19% 4	8197
	11th to 20th	Night	36% 4 6% 25% 23% 6%	7680
	21st to end	Night	41% 4 10% 28% 14% 3	8401
February	1st to 10th	Night	43% 4 11% 24% 16% 2	2730
	11th to 20th	Night	45% 4 7% 23% 16% 4	2479
	21st to end	Night	42% 5% 8% 22% 18% 5%	2076
March	1st to 10th	Night	40% 5% 9% 21% 17% 8%	5317
	11th to 20th	Night	37% 5% 8% 22% 21% 7%	5090
	21st to end	Night	39% 5% 10% 24% 16% 6%	5336
April	1st to 10th	Night	41% 6% 12% 18% 19% 4	2100
	11th to 20th	Night	33% 6% 11% 23% 22% 5%	2075
	21st to end	Night	37% 7% 12% 23% 17% 4	2100
May	1st to 10th	Night	46% 10% 16% 19% 8% 1	4531
	11th to 20th	Night	49% 7% 13% 22% 8% 1	3699
	21st to end	Night	45% 9% 12% 22% 12%	3927
June	1st to 10th	Night	40% 9% 12% 23% 15% 1	1600
	11th to 20th	Night	37% 10% 15% 22% 15% 1	1600
	21st to end	Night	32% 9% 17% 24% 16% 2	1600
July	1st to 10th	Night	39% 11% 17% 19% 12% 2	3560
	11th to 20th	Night	42% 12% 22% 19% 5%	3612
	21st to end	Night	39% 10% 13% 23% 14%	4297
August	1st to 10th	Night	48% 9% 16% 21% 6%	2927
	11th to 20th	Night	39% 9% 16% 25% 11%	3227
	21st to end	Night	31% 8% 11% 26% 23% 1	3586
September	1st to 10th	Night	36% 9% 14% 21% 16% 4	2000
	11th to 20th	Night	37% 7% 10% 25% 19% 2	2007
	21st to end	Night	48% 8% 12% 16% 14% 2	2227
October	1st to 10th	Night	34% 6% 12% 24% 22% 2	3920
	11th to 20th	Night	28% 4 8% 23% 28% 10%	3899
	21st to end	Night	24% 3 8% 30% 24% 11%	4252
November	1st to 10th	Night	37% 5% 12% 24% 19% 4	2629
	11th to 20th	Night	40% 6% 10% 20% 18% 5%	2730
	21st to end	Night	34% 5% 11% 27% 19% 3	2783
December	1st to 10th	Night	34% 6% 11% 27% 20% 3	4720
	11th to 20th	Night	47% 6% 11% 20% 11% 4	5348
	21st to end	Night	39% 5% 14% 27% 13% 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	22% 14% 28% 28% 8%	223
	11th to 20th	Day	19% 15% 33% 25% 8%	330
	21st to end	Day	18% 11% 30% 32% 8%	363
February	1st to 10th	Day	18% 14% 22% 35% 12%	330
	11th to 20th	Day	28% 13% 31% 22% 5%	515
	21st to end	Day	22% 9% 32% 28% 7% 1	446
March	1st to 10th	Day	17% 11% 31% 33% 8% 1	540
	11th to 20th	Day	17% 9% 31% 32% 10% 1	540
	21st to end	Day	14% 11% 31% 32% 11% 1	594
April	1st to 10th	Day	13% 11% 31% 31% 13% 2	540
	11th to 20th	Day	10% 7% 26% 36% 18% 3	532
	21st to end	Day	14% 8% 24% 34% 18% 2	540
May	1st to 10th	Day	15% 8% 21% 31% 21% 4	507
	11th to 20th	Day	17% 4 20% 30% 23% 5%	527
	21st to end	Day	17% 3 13% 27% 28% 11%	573
June	1st to 10th	Day	12% 2 11% 30% 35% 10%	530
	11th to 20th	Day	9% 2 14% 31% 31% 12%	530
	21st to end	Day	8% 3 11% 31% 37% 10%	530
July	1st to 10th	Day	9% 3 7% 27% 37% 17%	525
	11th to 20th	Day	7% 2 7% 22% 45% 17%	524
	21st to end	Day	10% 1 8% 24% 46% 11%	576
August	1st to 10th	Day	12% 2 9% 29% 35% 13%	526
	11th to 20th	Day	11% 1 10% 26% 34% 19%	519
	21st to end	Day	10% 1 13% 24% 36% 16%	583
September	1st to 10th	Day	15% 2 12% 24% 31% 16%	530
	11th to 20th	Day	13% 4 14% 23% 33% 12%	530
	21st to end	Day	23% 6% 17% 25% 23% 7%	530
October	1st to 10th	Day	15% 5% 14% 28% 27% 12%	530
	11th to 20th	Day	18% 9% 20% 26% 22% 5%	530
	21st to end	Day	15% 9% 25% 27% 19% 5%	583
November	1st to 10th	Day	15% 10% 26% 24% 19% 5%	444
	11th to 20th	Day	16% 12% 30% 28% 13% 2	430
	21st to end	Day	18% 14% 24% 23% 17% 3	373
December	1st to 10th	Day	24% 9% 29% 26% 11% 1	220
	11th to 20th	Day	23% 11% 30% 22% 15%	220
	21st to end	Day	18% 11% 30% 28% 12% 2	242
January	1st to 10th	Night	17% 17% 33% 27% 6%	840
	11th to 20th	Night	19% 14% 33% 26% 8%	840
	21st to end	Night	20% 12% 35% 29% 4	924
February	1st to 10th	Night	20% 9% 35% 30% 5%	840
	11th to 20th	Night	24% 13% 37% 23% 3	823
	21st to end	Night	21% 11% 31% 32% 5% 1	692
March	1st to 10th	Night	17% 11% 32% 31% 9%	840
	11th to 20th	Night	20% 8% 33% 29% 7% 2	840
	21st to end	Night	19% 8% 31% 33% 8% 1	924
April	1st to 10th	Night	16% 9% 35% 31% 8% 1	840
	11th to 20th	Night	13% 6% 29% 39% 13% 1	831
	21st to end	Night	15% 5% 28% 38% 13% 1	840
May	1st to 10th	Night	16% 7% 26% 36% 14% 2	805
	11th to 20th	Night	16% 4 22% 37% 19% 2	452
	21st to end	Night	14% 3 14% 31% 32% 6%	433
June	1st to 10th	Night	13% 3 15% 38% 29% 3	400
	11th to 20th	Night	9% 1 13% 44% 28% 6%	400
	21st to end	Night	8% 2 14% 38% 35% 5%	400
July	1st to 10th	Night	9% 1 9% 36% 37% 8%	390
	11th to 20th	Night	8% 1 6% 28% 47% 10%	409
	21st to end	Night	7% 3 10% 34% 39% 7%	657
August	1st to 10th	Night	11% 2 9% 33% 39% 7%	607
	11th to 20th	Night	12% 1 10% 31% 38% 8%	790
	21st to end	Night	9% 1 9% 31% 39% 10%	880
September	1st to 10th	Night	12% 2 13% 28% 34% 11%	800
	11th to 20th	Night	12% 3 13% 26% 37% 9%	800
	21st to end	Night	21% 4 16% 29% 28% 3	800
October	1st to 10th	Night	18% 5% 16% 28% 26% 8%	800
	11th to 20th	Night	17% 8% 22% 30% 20% 3	800
	21st to end	Night	18% 9% 23% 29% 17% 4	880
November	1st to 10th	Night	15% 9% 25% 28% 17% 5%	820
	11th to 20th	Night	17% 11% 28% 30% 12% 2	840
	21st to end	Night	15% 14% 27% 29% 14% 2	840
December	1st to 10th	Night	22% 10% 34% 23% 10% 1	840
	11th to 20th	Night	18% 10% 36% 26% 9%	840
	21st to end	Night	18% 11% 30% 30% 10%	924

Page generated at 2026-04-29 02:21:42. Version ac07

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