Waynesboro
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Waynesboro clear sky chart from 2005-11-06 to 2026-04-02.

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% 5% 5% 5% 4 6% 8% 42%	131062
	Night	12% 6% 2 6% 4 4 4 4 5% 7% 45%	130756
Transparency	Day	39% 6% 12% 23% 16% 4	134668
	Night	37% 5% 11% 23% 18% 5%	135220
Seeing	Day	20% 13% 24% 23% 14% 5%	16793
	Night	16% 12% 24% 31% 15% 2	26725

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	11% 7% 2 5% 4 3 4 4 5% 6% 48%	5258
	11th to 20th	Day	8% 8% 3 7% 4 4 3 3 4 4 53%	5280
	21st to end	Day	12% 7% 3 7% 4 5% 4 3 4 5% 47%	5780
February	1st to 10th	Day	10% 8% 3 8% 4 5% 4 4 5% 6% 42%	1890
	11th to 20th	Day	15% 8% 2 6% 4 4 5% 3 6% 6% 41%	1843
	21st to end	Day	15% 8% 2 7% 5% 4 4 4 5% 6% 39%	1809
March	1st to 10th	Day	14% 7% 3 7% 4 4 4 4 5% 7% 41%	5045
	11th to 20th	Day	8% 5% 2 6% 4 4 4 3 5% 7% 51%	5090
	21st to end	Day	13% 7% 2 7% 5% 5% 5% 4 5% 6% 40%	5586
April	1st to 10th	Day	9% 8% 2 6% 5% 4 5% 3 6% 8% 45%	2354
	11th to 20th	Day	11% 6% 2 5% 4 4 4 3 6% 7% 46%	2374
	21st to end	Day	14% 7% 2 7% 5% 5% 5% 4 5% 6% 41%	2462
May	1st to 10th	Day	12% 6% 2 7% 6% 6% 7% 5% 7% 9% 33%	5862
	11th to 20th	Day	20% 7% 2 7% 5% 4 5% 4 6% 8% 32%	5861
	21st to end	Day	14% 6% 2 6% 4 5% 5% 4 6% 10% 39%	6652
June	1st to 10th	Day	11% 5% 2 5% 4 5% 5% 5% 7% 9% 42%	2800
	11th to 20th	Day	10% 5% 2 6% 5% 6% 6% 5% 7% 10% 37%	2800
	21st to end	Day	7% 5% 2 6% 5% 5% 5% 5% 8% 10% 43%	2800
July	1st to 10th	Day	6% 4 2 7% 5% 5% 6% 5% 8% 10% 41%	5912
	11th to 20th	Day	7% 5% 3 8% 6% 7% 8% 6% 9% 13% 28%	5900
	21st to end	Day	8% 5% 3 7% 6% 6% 7% 5% 8% 11% 33%	6424
August	1st to 10th	Day	13% 5% 2 7% 5% 6% 6% 5% 8% 10% 32%	4234
	11th to 20th	Day	9% 5% 2 6% 6% 6% 6% 5% 8% 11% 36%	4123
	21st to end	Day	7% 5% 2 6% 4 4 5% 4 6% 9% 47%	4312
September	1st to 10th	Day	12% 6% 2 6% 4 4 5% 4 4 7% 48%	2400
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 3 5% 8% 44%	2283
	21st to end	Day	22% 7% 2 6% 4 4 4 4 6% 7% 34%	2150
October	1st to 10th	Day	15% 5% 2 5% 4 3 3 3 5% 7% 48%	2000
	11th to 20th	Day	15% 5% 1 4 3 3 3 3 5% 6% 51%	2000
	21st to end	Day	12% 6% 2 5% 3 3 4 3 4 6% 52%	2200
November	1st to 10th	Day	11% 5% 2 4 4 4 3 3 5% 6% 55%	2057
	11th to 20th	Day	12% 6% 2 4 4 4 3 3 6% 6% 50%	1878
	21st to end	Day	12% 5% 2 5% 4 4 4 3 6% 6% 49%	1680
December	1st to 10th	Day	10% 6% 2 5% 3 4 3 3 6% 6% 52%	2680
	11th to 20th	Day	16% 5% 2 5% 3 3 4 3 5% 7% 47%	3070
	21st to end	Day	16% 8% 2 7% 4 4 4 4 6% 8% 37%	4213
January	1st to 10th	Night	9% 6% 2 4 4 4 5% 4 5% 6% 50%	7635
	11th to 20th	Night	10% 7% 2 5% 2 3 3 3 4 5% 56%	7680
	21st to end	Night	12% 7% 2 5% 4 4 3 2 4 5% 52%	8401
February	1st to 10th	Night	10% 8% 2 6% 4 4 5% 4 6% 7% 43%	2730
	11th to 20th	Night	17% 9% 3 5% 4 3 4 3 4 6% 41%	2663
	21st to end	Night	12% 8% 2 6% 4 4 4 5% 5% 7% 43%	1993
March	1st to 10th	Night	15% 5% 2 5% 3 3 4 4 5% 6% 47%	5028
	11th to 20th	Night	9% 4 2 4 4 4 4 4 5% 8% 53%	5090
	21st to end	Night	11% 6% 3 7% 5% 4 5% 4 5% 6% 45%	5588
April	1st to 10th	Night	11% 8% 2 7% 5% 4 4 3 6% 8% 42%	2067
	11th to 20th	Night	11% 6% 2 5% 4 3 4 4 5% 9% 47%	1975
	21st to end	Night	14% 6% 2 6% 4 4 5% 4 6% 7% 44%	1955
May	1st to 10th	Night	15% 7% 3 7% 4 4 4 4 6% 9% 37%	4033
	11th to 20th	Night	22% 8% 2 6% 4 4 5% 4 6% 7% 32%	4032
	21st to end	Night	14% 6% 2 6% 4 4 5% 4 6% 10% 39%	4197
June	1st to 10th	Night	9% 6% 2 6% 4 4 5% 5% 6% 11% 44%	1600
	11th to 20th	Night	10% 5% 2 6% 5% 4 6% 5% 7% 9% 44%	1600
	21st to end	Night	8% 5% 2 5% 4 5% 5% 4 6% 11% 47%	1600
July	1st to 10th	Night	7% 5% 2 6% 4 5% 5% 5% 8% 10% 43%	4026
	11th to 20th	Night	7% 8% 3 10% 7% 6% 7% 6% 7% 10% 28%	4057
	21st to end	Night	7% 6% 3 9% 6% 6% 6% 5% 8% 10% 33%	4427
August	1st to 10th	Night	14% 6% 2 7% 6% 5% 5% 4 8% 9% 35%	2915
	11th to 20th	Night	8% 6% 3 9% 6% 6% 5% 4 7% 9% 36%	2893
	21st to end	Night	10% 7% 2 6% 4 5% 5% 3 6% 9% 44%	3586
September	1st to 10th	Night	12% 5% 2 5% 4 4 4 3 5% 7% 49%	2000
	11th to 20th	Night	12% 5% 2 5% 4 4 4 4 6% 8% 46%	2113
	21st to end	Night	22% 8% 2 6% 3 4 4 2 5% 5% 39%	2250
October	1st to 10th	Night	17% 5% 2 6% 4 3 4 2 5% 6% 47%	2400
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 5% 6% 51%	2400
	21st to end	Night	12% 4 2 5% 3 3 3 3 5% 7% 53%	2640
November	1st to 10th	Night	10% 7% 2 5% 3 4 3 2 4 5% 53%	2461
	11th to 20th	Night	12% 6% 2 6% 3 4 4 4 4 6% 50%	2736
	21st to end	Night	12% 5% 2 5% 4 4 5% 4 5% 6% 49%	2940
December	1st to 10th	Night	9% 6% 2 5% 3 4 4 4 5% 7% 52%	4720
	11th to 20th	Night	13% 8% 3 6% 4 4 4 4 5% 6% 44%	5345
	21st to end	Night	12% 6% 2 7% 4 5% 4 4 6% 7% 42%	6980

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	37% 4 8% 24% 20% 7%	5259
	11th to 20th	Day	36% 3 5% 18% 24% 14%	5280
	21st to end	Day	40% 3 5% 29% 18% 5%	5780
February	1st to 10th	Day	43% 4 9% 24% 17% 3	1890
	11th to 20th	Day	43% 4 9% 21% 18% 5%	1852
	21st to end	Day	46% 4 9% 20% 16% 6%	1809
March	1st to 10th	Day	42% 5% 8% 19% 16% 10%	5045
	11th to 20th	Day	32% 5% 8% 27% 20% 8%	5090
	21st to end	Day	45% 5% 9% 18% 17% 6%	5586
April	1st to 10th	Day	37% 5% 11% 22% 18% 7%	2354
	11th to 20th	Day	36% 5% 11% 22% 20% 5%	2374
	21st to end	Day	43% 5% 10% 24% 13% 4	2462
May	1st to 10th	Day	45% 7% 15% 21% 11% 1	5897
	11th to 20th	Day	49% 7% 12% 20% 11% 1	5865
	21st to end	Day	40% 7% 15% 21% 16% 3	6667
June	1st to 10th	Day	36% 7% 16% 25% 15% 1	2800
	11th to 20th	Day	40% 9% 16% 21% 14% 1	2800
	21st to end	Day	33% 9% 16% 27% 14% 1	2800
July	1st to 10th	Day	35% 11% 19% 20% 11% 4	5847
	11th to 20th	Day	42% 12% 19% 20% 6% 1	5831
	21st to end	Day	41% 9% 15% 24% 12%	6240
August	1st to 10th	Day	43% 8% 19% 24% 6%	4221
	11th to 20th	Day	37% 9% 15% 29% 10% 1	4162
	21st to end	Day	32% 7% 19% 30% 10% 1	4312
September	1st to 10th	Day	37% 6% 14% 19% 20% 4	2400
	11th to 20th	Day	38% 6% 7% 27% 19% 3	2283
	21st to end	Day	48% 6% 10% 18% 16% 2	2150
October	1st to 10th	Day	33% 5% 8% 20% 29% 5%	3260
	11th to 20th	Day	24% 3 8% 27% 24% 13%	3240
	21st to end	Day	22% 3 9% 30% 23% 13%	3538
November	1st to 10th	Day	31% 4 9% 25% 26% 5%	2057
	11th to 20th	Day	35% 4 9% 22% 22% 8%	1878
	21st to end	Day	35% 4 9% 25% 23% 3	1680
December	1st to 10th	Day	33% 4 11% 25% 20% 6%	2680
	11th to 20th	Day	37% 5% 14% 23% 17% 5%	3066
	21st to end	Day	45% 5% 12% 22% 15% 1	4213
January	1st to 10th	Night	33% 5% 8% 24% 23% 7%	7636
	11th to 20th	Night	32% 3 6% 21% 27% 11%	7680
	21st to end	Night	36% 2 7% 26% 23% 5%	8401
February	1st to 10th	Night	39% 5% 12% 25% 17% 3	2730
	11th to 20th	Night	44% 4 8% 20% 18% 6%	2665
	21st to end	Night	40% 4 12% 22% 16% 6%	1993
March	1st to 10th	Night	38% 5% 8% 22% 20% 9%	5028
	11th to 20th	Night	28% 5% 8% 24% 28% 7%	5090
	21st to end	Night	39% 4 11% 21% 20% 5%	5588
April	1st to 10th	Night	39% 6% 12% 19% 19% 5%	2067
	11th to 20th	Night	35% 4 15% 21% 21% 5%	1975
	21st to end	Night	39% 4 11% 27% 15% 4	1955
May	1st to 10th	Night	45% 6% 17% 19% 11% 2	4060
	11th to 20th	Night	50% 6% 12% 22% 9% 1	4033
	21st to end	Night	40% 7% 17% 25% 9% 2	4204
June	1st to 10th	Night	33% 9% 13% 30% 14% 1	1600
	11th to 20th	Night	36% 8% 16% 26% 12% 2	1600
	21st to end	Night	31% 8% 18% 23% 17% 3	1600
July	1st to 10th	Night	36% 10% 20% 19% 13% 2	3983
	11th to 20th	Night	48% 12% 17% 17% 5% 1	4006
	21st to end	Night	42% 11% 16% 21% 10%	4297
August	1st to 10th	Night	44% 7% 18% 24% 5% 1	2904
	11th to 20th	Night	40% 9% 16% 24% 10%	2920
	21st to end	Night	35% 6% 18% 32% 8% 2	3586
September	1st to 10th	Night	35% 6% 15% 21% 18% 5%	2000
	11th to 20th	Night	36% 6% 10% 27% 18% 3	2113
	21st to end	Night	48% 5% 10% 20% 16% 3	2250
October	1st to 10th	Night	41% 4 10% 20% 20% 5%	3920
	11th to 20th	Night	26% 3 8% 23% 29% 11%	3899
	21st to end	Night	21% 3 10% 30% 26% 10%	4252
November	1st to 10th	Night	34% 3 9% 22% 26% 6%	2461
	11th to 20th	Night	36% 3 8% 22% 24% 6%	2736
	21st to end	Night	36% 4 8% 25% 22% 5%	2940
December	1st to 10th	Night	31% 5% 10% 28% 22% 3	4720
	11th to 20th	Night	42% 5% 11% 18% 18% 6%	5348
	21st to end	Night	40% 5% 12% 24% 18% 2	6980

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% 28% 25% 13% 3	330
	11th to 20th	Day	32% 31% 24% 13% 1	330
	21st to end	Day	28% 28% 29% 12% 2	363
February	1st to 10th	Day	26% 28% 34% 11% 2	330
	11th to 20th	Day	45% 22% 25% 8%	330
	21st to end	Day	33% 20% 28% 17% 2	415
March	1st to 10th	Day	25% 22% 28% 20% 5% 1	540
	11th to 20th	Day	27% 24% 27% 17% 4 1	540
	21st to end	Day	23% 18% 33% 20% 5% 1	594
April	1st to 10th	Day	25% 24% 26% 16% 9% 1	504
	11th to 20th	Day	22% 15% 27% 22% 11% 3	492
	21st to end	Day	22% 16% 31% 20% 9% 2	500
May	1st to 10th	Day	20% 21% 29% 19% 8% 3	503
	11th to 20th	Day	23% 11% 27% 22% 13% 3	527
	21st to end	Day	20% 9% 22% 25% 18% 7%	573
June	1st to 10th	Day	13% 7% 28% 26% 19% 6%	530
	11th to 20th	Day	14% 7% 25% 29% 18% 8%	530
	21st to end	Day	9% 8% 24% 32% 19% 8%	530
July	1st to 10th	Day	11% 4 15% 33% 27% 10%	525
	11th to 20th	Day	6% 2 19% 35% 26% 13%	524
	21st to end	Day	11% 4 18% 32% 24% 11%	576
August	1st to 10th	Day	14% 5% 18% 28% 25% 11%	526
	11th to 20th	Day	12% 3 19% 29% 25% 12%	519
	21st to end	Day	10% 4 16% 32% 21% 16%	583
September	1st to 10th	Day	14% 5% 17% 25% 23% 16%	530
	11th to 20th	Day	15% 4 16% 28% 26% 11%	530
	21st to end	Day	28% 9% 19% 23% 16% 4	530
October	1st to 10th	Day	19% 7% 19% 30% 18% 7%	530
	11th to 20th	Day	18% 16% 23% 23% 18% 3	530
	21st to end	Day	16% 16% 31% 21% 13% 3	583
November	1st to 10th	Day	17% 12% 30% 27% 11% 3	535
	11th to 20th	Day	23% 15% 28% 23% 10% 1	370
	21st to end	Day	27% 18% 29% 18% 7% 1	220
December	1st to 10th	Day	25% 23% 31% 16% 5% 1	220
	11th to 20th	Day	25% 20% 25% 21% 8% 1	220
	21st to end	Day	27% 22% 29% 17% 5%	281
January	1st to 10th	Night	18% 22% 35% 22% 3	840
	11th to 20th	Night	20% 19% 31% 27% 3	840
	21st to end	Night	18% 21% 35% 25% 2	924
February	1st to 10th	Night	15% 19% 33% 30% 2	840
	11th to 20th	Night	23% 25% 32% 19% 1	823
	21st to end	Night	19% 21% 34% 24% 2	692
March	1st to 10th	Night	16% 21% 31% 28% 4	840
	11th to 20th	Night	25% 17% 29% 23% 5% 1	840
	21st to end	Night	19% 15% 33% 27% 5% 1	924
April	1st to 10th	Night	17% 20% 35% 22% 6%	805
	11th to 20th	Night	15% 16% 29% 28% 10% 1	791
	21st to end	Night	18% 10% 31% 32% 9% 1	755
May	1st to 10th	Night	20% 9% 24% 30% 17% 1	600
	11th to 20th	Night	19% 7% 21% 36% 16% 1	591
	21st to end	Night	16% 3 17% 37% 25% 3	555
June	1st to 10th	Night	9% 3 18% 48% 21% 2	400
	11th to 20th	Night	11% 4 15% 41% 28% 2	400
	21st to end	Night	10% 3 16% 44% 24% 3	400
July	1st to 10th	Night	10% 2 13% 32% 36% 6%	566
	11th to 20th	Night	6% 2 8% 35% 43% 6%	582
	21st to end	Night	8% 4 11% 38% 33% 6%	657
August	1st to 10th	Night	12% 3 10% 39% 32% 5%	597
	11th to 20th	Night	13% 3 8% 36% 36% 4	599
	21st to end	Night	13% 3 10% 36% 34% 5%	880
September	1st to 10th	Night	15% 2 12% 36% 31% 6%	800
	11th to 20th	Night	14% 3 12% 35% 32% 4	800
	21st to end	Night	26% 6% 15% 31% 20% 2	800
October	1st to 10th	Night	19% 6% 17% 31% 24% 4	800
	11th to 20th	Night	16% 11% 24% 32% 16% 1	800
	21st to end	Night	15% 10% 28% 32% 13% 2	880
November	1st to 10th	Night	15% 10% 24% 36% 13% 2	820
	11th to 20th	Night	17% 14% 27% 32% 9% 1	840
	21st to end	Night	17% 16% 28% 29% 9% 1	840
December	1st to 10th	Night	18% 15% 32% 28% 6%	840
	11th to 20th	Night	17% 14% 29% 35% 5%	840
	21st to end	Night	16% 15% 29% 36% 4	924

Page generated at 2026-03-30 02:18:44. Version ac07

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