Steubenville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Steubenville clear sky chart from 2005-11-06 to 2025-11-18.

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	15% 11% 4 9% 5% 5% 5% 4 5% 7% 31%	126414
	Night	16% 11% 4 9% 5% 4 4 3 5% 6% 32%	123939
Transparency	Day	33% 39% 6% 14% 7% 1	130033
	Night	34% 38% 6% 13% 7% 1	128389
Seeing	Day	24% 13% 27% 21% 11% 4	16061
	Night	23% 11% 26% 26% 12% 1	25851

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	17% 19% 7% 19% 5% 3 3 3 3 5% 16%	4056
	11th to 20th	Day	13% 22% 9% 16% 8% 6% 3 2 3 3 15%	4060
	21st to end	Day	20% 21% 6% 11% 7% 6% 4 3 3 5% 15%	4466
February	1st to 10th	Day	19% 17% 5% 9% 6% 5% 3 3 4 5% 23%	1800
	11th to 20th	Day	17% 15% 6% 12% 5% 5% 4 3 5% 6% 22%	1768
	21st to end	Day	20% 15% 4 10% 5% 4 4 3 4 6% 26%	1653
March	1st to 10th	Day	16% 14% 5% 10% 5% 4 4 3 5% 6% 28%	4935
	11th to 20th	Day	12% 8% 3 9% 5% 6% 5% 3 5% 6% 38%	4980
	21st to end	Day	19% 10% 3 9% 5% 4 5% 4 5% 6% 30%	5465
April	1st to 10th	Day	15% 14% 3 9% 5% 4 4 4 6% 7% 29%	2275
	11th to 20th	Day	15% 12% 3 8% 6% 4 4 3 5% 6% 35%	2447
	21st to end	Day	20% 9% 3 6% 5% 5% 4 4 5% 7% 33%	2600
May	1st to 10th	Day	20% 9% 4 8% 5% 5% 5% 4 6% 7% 27%	5862
	11th to 20th	Day	18% 9% 3 7% 5% 5% 5% 4 7% 7% 30%	5861
	21st to end	Day	18% 8% 2 7% 4 5% 5% 5% 7% 8% 31%	6605
June	1st to 10th	Day	12% 8% 3 7% 5% 6% 6% 4 7% 9% 35%	2800
	11th to 20th	Day	13% 8% 3 7% 5% 5% 5% 5% 7% 9% 35%	2800
	21st to end	Day	12% 6% 2 5% 5% 5% 6% 5% 7% 10% 38%	2800
July	1st to 10th	Day	9% 6% 2 7% 5% 5% 5% 4 6% 9% 41%	5929
	11th to 20th	Day	10% 7% 3 7% 5% 6% 6% 5% 7% 9% 34%	5900
	21st to end	Day	10% 8% 3 8% 5% 5% 6% 4 7% 8% 37%	6424
August	1st to 10th	Day	11% 7% 3 9% 5% 5% 6% 5% 6% 9% 32%	4234
	11th to 20th	Day	11% 6% 2 6% 5% 6% 6% 5% 8% 9% 36%	4174
	21st to end	Day	7% 4 2 6% 5% 6% 7% 6% 7% 10% 40%	4492
September	1st to 10th	Day	15% 5% 2 5% 3 4 4 4 5% 8% 45%	2355
	11th to 20th	Day	10% 6% 2 6% 4 5% 4 4 5% 9% 45%	2200
	21st to end	Day	19% 8% 3 7% 4 4 4 3 5% 6% 36%	2200
October	1st to 10th	Day	14% 6% 3 7% 4 4 5% 3 5% 7% 43%	2027
	11th to 20th	Day	18% 8% 3 7% 5% 4 5% 3 5% 5% 38%	2000
	21st to end	Day	22% 11% 3 6% 4 4 4 3 4 6% 34%	2200
November	1st to 10th	Day	11% 9% 3 6% 4 5% 4 3 5% 6% 43%	1937
	11th to 20th	Day	17% 14% 4 9% 5% 4 4 3 5% 5% 31%	1798
	21st to end	Day	17% 15% 6% 9% 4 4 5% 4 5% 6% 25%	1600
December	1st to 10th	Day	19% 12% 6% 14% 6% 4 4 3 4 4 22%	2600
	11th to 20th	Day	23% 17% 7% 11% 4 3 2 2 3 4 23%	2990
	21st to end	Day	22% 20% 6% 12% 6% 4 4 3 5% 5% 14%	4121
January	1st to 10th	Night	15% 18% 7% 22% 6% 4 3 3 4 3 15%	5889
	11th to 20th	Night	15% 19% 8% 14% 8% 5% 4 3 4 4 15%	5900
	21st to end	Night	22% 16% 6% 13% 6% 4 3 2 3 4 21%	6490
February	1st to 10th	Night	20% 14% 5% 10% 6% 5% 4 3 4 5% 24%	2600
	11th to 20th	Night	19% 13% 4 12% 6% 4 4 3 4 6% 25%	2513
	21st to end	Night	19% 14% 5% 12% 4 5% 4 3 5% 5% 24%	1976
March	1st to 10th	Night	21% 12% 4 8% 5% 3 3 2 3 5% 32%	4918
	11th to 20th	Night	13% 10% 5% 7% 4 3 4 3 5% 7% 39%	4980
	21st to end	Night	17% 11% 3 9% 5% 5% 4 3 4 5% 34%	5467
April	1st to 10th	Night	18% 13% 3 6% 6% 3 5% 4 5% 7% 32%	2125
	11th to 20th	Night	16% 9% 3 7% 5% 4 4 3 6% 7% 36%	1917
	21st to end	Night	15% 9% 3 6% 5% 4 4 4 5% 7% 38%	1800
May	1st to 10th	Night	24% 12% 4 9% 5% 4 4 4 4 6% 24%	4033
	11th to 20th	Night	16% 9% 3 7% 4 4 4 3 5% 8% 36%	4032
	21st to end	Night	17% 8% 3 6% 4 4 4 3 7% 8% 35%	4246
June	1st to 10th	Night	9% 7% 2 7% 6% 4 5% 3 5% 8% 45%	1600
	11th to 20th	Night	11% 6% 2 7% 4 4 4 4 6% 12% 39%	1600
	21st to end	Night	9% 6% 2 5% 5% 6% 5% 4 6% 10% 44%	1600
July	1st to 10th	Night	10% 8% 3 8% 5% 4 4 4 6% 7% 43%	4009
	11th to 20th	Night	11% 6% 3 7% 5% 5% 5% 5% 7% 9% 37%	4057
	21st to end	Night	8% 6% 3 7% 5% 5% 5% 4 6% 8% 43%	4427
August	1st to 10th	Night	11% 8% 3 8% 4 4 6% 5% 7% 8% 35%	2915
	11th to 20th	Night	11% 8% 3 7% 5% 5% 4 3 5% 7% 43%	2875
	21st to end	Night	7% 5% 2 5% 5% 5% 6% 5% 7% 9% 45%	3373
September	1st to 10th	Night	13% 4 2 5% 3 4 4 3 4 6% 52%	2041
	11th to 20th	Night	9% 5% 1 4 4 3 3 4 5% 7% 54%	2200
	21st to end	Night	17% 7% 2 7% 4 5% 4 3 5% 5% 41%	2200
October	1st to 10th	Night	14% 6% 2 5% 4 3 4 3 5% 6% 47%	2371
	11th to 20th	Night	16% 7% 3 7% 4 5% 5% 4 4 7% 39%	2400
	21st to end	Night	23% 8% 2 6% 4 3 4 3 4 7% 36%	2640
November	1st to 10th	Night	13% 8% 3 6% 4 4 4 3 5% 6% 46%	2576
	11th to 20th	Night	18% 11% 3 8% 5% 4 3 4 5% 6% 32%	2754
	21st to end	Night	20% 13% 5% 7% 5% 4 4 4 5% 5% 28%	2800
December	1st to 10th	Night	18% 16% 8% 14% 5% 4 4 3 5% 5% 18%	4580
	11th to 20th	Night	21% 18% 7% 10% 4 3 3 3 4 5% 22%	5205
	21st to end	Night	23% 18% 6% 10% 5% 5% 4 3 4 6% 16%	6830

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	56% 28% 6% 7% 3	4057
	11th to 20th	Day	59% 26% 3 6% 4 2	4060
	21st to end	Day	54% 28% 4 8% 5%	4466
February	1st to 10th	Day	26% 62% 3 7% 2	1800
	11th to 20th	Day	25% 60% 3 9% 4	1777
	21st to end	Day	22% 62% 4 6% 5% 1	1653
March	1st to 10th	Day	43% 29% 6% 16% 5% 1	4935
	11th to 20th	Day	32% 31% 6% 22% 7% 2	4980
	21st to end	Day	38% 30% 5% 16% 10% 1	5465
April	1st to 10th	Day	24% 61% 3 7% 3	2275
	11th to 20th	Day	19% 63% 4 9% 4 1	2447
	21st to end	Day	20% 62% 3 10% 4	2600
May	1st to 10th	Day	41% 31% 7% 13% 6% 3	5897
	11th to 20th	Day	37% 32% 7% 18% 6%	5865
	21st to end	Day	37% 31% 7% 15% 8% 2	6620
June	1st to 10th	Day	20% 63% 4 8% 5%	2800
	11th to 20th	Day	19% 63% 4 9% 5%	2800
	21st to end	Day	16% 62% 6% 10% 6%	2800
July	1st to 10th	Day	30% 28% 7% 21% 13% 1	5864
	11th to 20th	Day	33% 29% 10% 19% 9%	5831
	21st to end	Day	31% 28% 7% 17% 15% 1	6240
August	1st to 10th	Day	32% 38% 9% 15% 6%	4221
	11th to 20th	Day	26% 38% 7% 22% 7%	4213
	21st to end	Day	22% 39% 9% 21% 9% 1	4492
September	1st to 10th	Day	15% 58% 5% 11% 10% 2	2355
	11th to 20th	Day	14% 58% 7% 11% 9% 1	2200
	21st to end	Day	22% 57% 4 12% 6%	2200
October	1st to 10th	Day	16% 36% 6% 25% 16% 1	3300
	11th to 20th	Day	27% 37% 6% 14% 12% 5%	3240
	21st to end	Day	20% 36% 8% 20% 14% 1	3538
November	1st to 10th	Day	23% 53% 5% 11% 6% 1	1937
	11th to 20th	Day	24% 55% 4 11% 6% 1	1798
	21st to end	Day	28% 58% 6% 7% 2	1600
December	1st to 10th	Day	43% 36% 10% 8% 3	2600
	11th to 20th	Day	47% 31% 7% 11% 3	2986
	21st to end	Day	55% 28% 5% 9% 3	4121
January	1st to 10th	Night	58% 26% 4 8% 3	5889
	11th to 20th	Night	57% 27% 5% 7% 3 1	5900
	21st to end	Night	52% 28% 6% 9% 5% 1	6490
February	1st to 10th	Night	25% 62% 3 7% 2	2600
	11th to 20th	Night	24% 61% 3 9% 4	2515
	21st to end	Night	24% 62% 4 5% 5%	1976
March	1st to 10th	Night	43% 29% 5% 16% 6% 1	4918
	11th to 20th	Night	29% 30% 9% 23% 6% 3	4980
	21st to end	Night	38% 30% 7% 14% 10% 1	5467
April	1st to 10th	Night	23% 63% 3 8% 3	2125
	11th to 20th	Night	20% 63% 4 7% 5% 1	1917
	21st to end	Night	18% 62% 4 9% 6%	1800
May	1st to 10th	Night	47% 31% 6% 9% 5% 3	4060
	11th to 20th	Night	34% 32% 7% 21% 7%	4033
	21st to end	Night	37% 31% 8% 17% 5% 2	4253
June	1st to 10th	Night	17% 63% 4 10% 6% 1	1600
	11th to 20th	Night	17% 63% 4 9% 7%	1600
	21st to end	Night	15% 63% 5% 10% 7%	1600
July	1st to 10th	Night	31% 28% 5% 20% 14% 1	3966
	11th to 20th	Night	34% 30% 13% 17% 7%	4006
	21st to end	Night	29% 28% 8% 15% 18% 2	4297
August	1st to 10th	Night	32% 40% 8% 14% 5% 1	2904
	11th to 20th	Night	29% 38% 5% 17% 11%	2902
	21st to end	Night	22% 39% 8% 23% 8%	3373
September	1st to 10th	Night	13% 58% 6% 12% 9% 1	2041
	11th to 20th	Night	12% 58% 6% 12% 12%	2200
	21st to end	Night	20% 57% 5% 9% 8%	2200
October	1st to 10th	Night	19% 36% 4 20% 19% 2	3878
	11th to 20th	Night	23% 36% 6% 15% 12% 8%	3899
	21st to end	Night	18% 35% 6% 22% 18% 2	4252
November	1st to 10th	Night	22% 53% 6% 11% 6% 1	2576
	11th to 20th	Night	23% 55% 3 11% 6% 1	2754
	21st to end	Night	27% 57% 6% 8% 2	2800
December	1st to 10th	Night	44% 37% 7% 10% 2	4580
	11th to 20th	Night	47% 32% 11% 9% 2	5208
	21st to end	Night	52% 28% 6% 10% 3	6830

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	36% 26% 24% 8% 5%	300
	11th to 20th	Day	36% 29% 27% 7% 2	300
	21st to end	Day	34% 28% 28% 8% 2	330
February	1st to 10th	Day	36% 24% 32% 8% 1	300
	11th to 20th	Day	41% 27% 26% 6% 1	300
	21st to end	Day	40% 26% 29% 5%	252
March	1st to 10th	Day	30% 21% 28% 17% 3	500
	11th to 20th	Day	33% 19% 31% 11% 6% 1	500
	21st to end	Day	32% 21% 30% 13% 4	550
April	1st to 10th	Day	36% 15% 27% 16% 5% 1	500
	11th to 20th	Day	27% 20% 26% 15% 8% 3	492
	21st to end	Day	29% 15% 31% 16% 7% 1	500
May	1st to 10th	Day	30% 16% 29% 16% 6% 3	503
	11th to 20th	Day	25% 12% 31% 20% 9% 4	527
	21st to end	Day	18% 12% 25% 23% 16% 6%	573
June	1st to 10th	Day	15% 9% 31% 28% 14% 3	530
	11th to 20th	Day	18% 10% 23% 29% 15% 5%	530
	21st to end	Day	17% 8% 27% 29% 15% 4	530
July	1st to 10th	Day	15% 5% 20% 29% 19% 11%	525
	11th to 20th	Day	14% 6% 23% 32% 16% 9%	524
	21st to end	Day	14% 5% 24% 30% 19% 8%	576
August	1st to 10th	Day	15% 5% 21% 31% 21% 8%	526
	11th to 20th	Day	16% 4 20% 30% 18% 11%	519
	21st to end	Day	12% 6% 22% 26% 23% 10%	583
September	1st to 10th	Day	20% 6% 20% 25% 22% 8%	530
	11th to 20th	Day	11% 4 19% 30% 24% 11%	530
	21st to end	Day	25% 10% 25% 22% 14% 4	530
October	1st to 10th	Day	17% 8% 27% 26% 15% 6%	530
	11th to 20th	Day	22% 16% 29% 22% 8% 2	530
	21st to end	Day	32% 13% 31% 18% 6% 1	583
November	1st to 10th	Day	21% 17% 33% 18% 7% 3	415
	11th to 20th	Day	35% 16% 30% 14% 5% 1	288
	21st to end	Day	30% 17% 43% 10% 1 1	200
December	1st to 10th	Day	36% 22% 29% 10% 3 1	200
	11th to 20th	Day	31% 24% 31% 13% 2	200
	21st to end	Day	36% 24% 24% 12% 3	255
January	1st to 10th	Night	31% 20% 33% 13% 3	800
	11th to 20th	Night	33% 20% 29% 15% 3	800
	21st to end	Night	29% 20% 30% 18% 3	880
February	1st to 10th	Night	31% 18% 29% 20% 2	800
	11th to 20th	Night	33% 20% 32% 14% 1	783
	21st to end	Night	30% 18% 32% 17% 3	660
March	1st to 10th	Night	28% 16% 32% 21% 3	800
	11th to 20th	Night	28% 17% 28% 21% 6% 1	800
	21st to end	Night	27% 16% 31% 21% 5% 1	880
April	1st to 10th	Night	28% 14% 30% 22% 6% 1	800
	11th to 20th	Night	25% 12% 32% 20% 10% 1	733
	21st to end	Night	21% 11% 33% 29% 6% 1	600
May	1st to 10th	Night	26% 7% 25% 31% 10% 1	600
	11th to 20th	Night	21% 8% 25% 30% 15% 1	591
	21st to end	Night	14% 3 22% 37% 21% 3	578
June	1st to 10th	Night	12% 4 24% 42% 18% 1	400
	11th to 20th	Night	14% 3 23% 39% 20% 1	400
	21st to end	Night	11% 4 26% 35% 24% 1	400
July	1st to 10th	Night	12% 1 15% 41% 25% 7%	562
	11th to 20th	Night	10% 3 18% 36% 29% 4	582
	21st to end	Night	14% 3 13% 41% 28% 2	657
August	1st to 10th	Night	9% 3 16% 41% 29% 3	597
	11th to 20th	Night	11% 2 13% 39% 30% 4	594
	21st to end	Night	12% 3 17% 33% 30% 5%	745
September	1st to 10th	Night	16% 2 19% 34% 26% 5%	800
	11th to 20th	Night	11% 3 16% 36% 30% 5%	800
	21st to end	Night	21% 7% 23% 26% 21% 3	800
October	1st to 10th	Night	17% 6% 20% 31% 22% 3	800
	11th to 20th	Night	21% 10% 30% 26% 11% 1	800
	21st to end	Night	28% 11% 27% 25% 8% 1	880
November	1st to 10th	Night	19% 11% 29% 29% 11%	820
	11th to 20th	Night	29% 14% 28% 22% 6% 1	829
	21st to end	Night	28% 14% 31% 21% 6% 1	800
December	1st to 10th	Night	35% 16% 27% 17% 5%	800
	11th to 20th	Night	31% 18% 28% 19% 4	800
	21st to end	Night	33% 14% 30% 21% 2	880

Page generated at 2025-11-15 00:55:57. Version ac07

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