Zanesville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Zanesville clear sky chart from 2005-11-06 to 2024-10-25.

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% 10% 3 8% 5% 5% 5% 4 6% 7% 33%	100879
	Night	16% 11% 4 8% 5% 4 4 3 5% 6% 35%	97861
Transparency	Day	48% 6% 11% 21% 12% 1	100691
	Night	49% 6% 11% 21% 12% 2	97719
Seeing	Day	22% 14% 27% 20% 12% 5%	14784
	Night	21% 11% 26% 27% 14% 2	24968

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	19% 21% 5% 10% 5% 4 4 3 4 5% 20%	2836
	11th to 20th	Day	15% 21% 8% 12% 5% 7% 5% 3 4 4 16%	2840
	21st to end	Day	27% 22% 7% 10% 6% 4 3 2 3 4 13%	3124
February	1st to 10th	Day	22% 15% 4 10% 6% 4 2 3 4 3 26%	1710
	11th to 20th	Day	16% 15% 5% 13% 4 4 4 4 4 6% 25%	1775
	21st to end	Day	20% 13% 5% 8% 5% 4 2 3 4 6% 31%	1570
March	1st to 10th	Day	21% 16% 5% 8% 5% 4 4 3 4 5% 26%	3339
	11th to 20th	Day	13% 9% 3 8% 5% 5% 5% 3 5% 6% 38%	3480
	21st to end	Day	20% 9% 3 8% 4 4 4 3 5% 6% 33%	3815
April	1st to 10th	Day	14% 13% 3 9% 6% 4 4 4 4 6% 33%	2090
	11th to 20th	Day	16% 10% 3 7% 4 4 5% 4 5% 6% 36%	2417
	21st to end	Day	18% 8% 3 6% 5% 5% 5% 4 6% 7% 33%	2470
May	1st to 10th	Day	20% 10% 3 8% 6% 5% 4 4 5% 7% 27%	4082
	11th to 20th	Day	20% 9% 3 7% 5% 4 4 3 5% 7% 34%	4081
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 5% 7% 11% 35%	4476
June	1st to 10th	Day	12% 7% 2 6% 5% 6% 5% 5% 6% 9% 37%	2470
	11th to 20th	Day	11% 6% 3 7% 5% 6% 5% 5% 7% 10% 35%	2470
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 5% 8% 9% 36%	2470
July	1st to 10th	Day	9% 7% 3 7% 5% 5% 6% 5% 6% 9% 38%	4120
	11th to 20th	Day	9% 6% 2 6% 4 4 5% 4 7% 11% 43%	4120
	21st to end	Day	12% 7% 3 7% 5% 7% 5% 5% 7% 8% 35%	4466
August	1st to 10th	Day	9% 7% 2 8% 5% 5% 5% 5% 8% 10% 36%	4104
	11th to 20th	Day	8% 7% 2 7% 5% 5% 6% 5% 9% 9% 36%	4044
	21st to end	Day	5% 4 2 5% 5% 5% 6% 5% 7% 10% 45%	4468
September	1st to 10th	Day	13% 7% 2 5% 3 3 4 3 6% 8% 47%	2119
	11th to 20th	Day	8% 5% 2 6% 4 4 5% 4 6% 9% 47%	2090
	21st to end	Day	20% 8% 2 6% 3 3 4 3 5% 6% 40%	2090
October	1st to 10th	Day	13% 6% 2 6% 4 4 4 3 6% 8% 43%	1994
	11th to 20th	Day	15% 7% 2 7% 4 4 5% 3 5% 7% 41%	1900
	21st to end	Day	21% 10% 2 7% 4 4 3 3 4 6% 36%	2027
November	1st to 10th	Day	10% 8% 3 7% 4 3 4 3 6% 6% 47%	1677
	11th to 20th	Day	17% 14% 3 6% 5% 3 4 3 5% 6% 35%	1710
	21st to end	Day	18% 14% 3 7% 4 4 5% 3 5% 5% 31%	1710
December	1st to 10th	Day	23% 15% 7% 10% 6% 3 4 3 4 5% 20%	1520
	11th to 20th	Day	18% 16% 6% 11% 5% 4 4 3 5% 5% 22%	2081
	21st to end	Day	22% 22% 5% 10% 6% 5% 4 3 4 5% 14%	3124
January	1st to 10th	Night	16% 20% 7% 12% 6% 5% 4 4 4 4 19%	4109
	11th to 20th	Night	15% 18% 6% 15% 6% 6% 6% 3 4 4 16%	4120
	21st to end	Night	26% 19% 8% 11% 5% 3 3 2 3 3 17%	4532
February	1st to 10th	Night	21% 15% 3 8% 6% 4 4 3 4 4 27%	2470
	11th to 20th	Night	19% 13% 4 10% 6% 6% 4 3 5% 5% 26%	2288
	21st to end	Night	20% 15% 7% 9% 5% 5% 3 3 3 5% 26%	1884
March	1st to 10th	Night	21% 13% 3 7% 4 4 4 3 4 5% 33%	3514
	11th to 20th	Night	14% 10% 3 7% 5% 4 5% 3 5% 6% 37%	3480
	21st to end	Night	19% 8% 2 7% 4 4 3 3 4 6% 39%	3817
April	1st to 10th	Night	16% 11% 3 5% 4 4 4 4 5% 6% 37%	2090
	11th to 20th	Night	15% 8% 3 6% 4 4 4 4 7% 7% 38%	1726
	21st to end	Night	15% 8% 2 7% 4 4 5% 4 6% 8% 37%	1710
May	1st to 10th	Night	26% 12% 3 7% 5% 4 4 3 5% 6% 26%	2813
	11th to 20th	Night	18% 8% 2 7% 4 4 3 3 4 7% 40%	2812
	21st to end	Night	10% 7% 2 6% 4 4 4 4 6% 10% 43%	3079
June	1st to 10th	Night	9% 7% 2 6% 5% 4 4 4 4 9% 46%	1710
	11th to 20th	Night	8% 6% 2 6% 4 5% 4 4 6% 11% 43%	1710
	21st to end	Night	11% 5% 1 5% 4 4 5% 5% 6% 9% 45%	1710
July	1st to 10th	Night	10% 8% 3 7% 4 4 4 3 6% 8% 44%	2840
	11th to 20th	Night	8% 5% 2 7% 5% 4 5% 5% 7% 8% 45%	2840
	21st to end	Night	7% 7% 3 7% 7% 5% 5% 5% 7% 9% 38%	3087
August	1st to 10th	Night	7% 7% 3 7% 6% 5% 6% 4 8% 9% 37%	2825
	11th to 20th	Night	9% 8% 3 9% 4 4 4 4 5% 7% 43%	2785
	21st to end	Night	5% 4 2 5% 4 5% 6% 5% 8% 10% 47%	3155
September	1st to 10th	Night	13% 4 1 5% 3 4 4 3 5% 6% 53%	2057
	11th to 20th	Night	9% 4 2 4 3 4 4 3 5% 8% 56%	2090
	21st to end	Night	17% 7% 3 5% 4 4 4 3 4 6% 45%	2090
October	1st to 10th	Night	12% 5% 2 6% 3 4 4 4 5% 7% 48%	2185
	11th to 20th	Night	14% 8% 3 5% 4 4 5% 4 5% 7% 41%	2280
	21st to end	Night	22% 8% 3 6% 4 4 3 3 4 6% 38%	2435
November	1st to 10th	Night	14% 8% 2 6% 3 3 3 3 4 6% 48%	2399
	11th to 20th	Night	16% 11% 3 7% 5% 5% 4 4 5% 6% 35%	2470
	21st to end	Night	20% 12% 4 8% 5% 3 4 3 5% 6% 30%	2470
December	1st to 10th	Night	23% 15% 5% 9% 5% 4 3 3 4 5% 23%	2648
	11th to 20th	Night	18% 16% 6% 9% 5% 3 4 3 5% 6% 26%	3099
	21st to end	Night	22% 20% 5% 10% 5% 5% 4 3 4 5% 17%	4532

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	66% 5% 11% 13% 5%	2837
	11th to 20th	Day	70% 6% 9% 11% 3	2840
	21st to end	Day	76% 4 7% 9% 3 1	3124
February	1st to 10th	Day	63% 3 10% 14% 9%	1710
	11th to 20th	Day	60% 5% 9% 17% 9%	1784
	21st to end	Day	56% 4 11% 19% 8% 2	1570
March	1st to 10th	Day	61% 4 10% 19% 5% 1	3339
	11th to 20th	Day	46% 6% 10% 27% 10% 1	3480
	21st to end	Day	50% 6% 10% 23% 11%	3815
April	1st to 10th	Day	52% 5% 10% 19% 11% 3	2090
	11th to 20th	Day	47% 6% 11% 18% 16% 3	2417
	21st to end	Day	49% 7% 9% 21% 12% 2	2470
May	1st to 10th	Day	55% 6% 10% 21% 7% 1	4120
	11th to 20th	Day	50% 6% 11% 19% 13% 1	4085
	21st to end	Day	40% 10% 14% 20% 12% 4	4489
June	1st to 10th	Day	42% 8% 11% 24% 14% 1	2470
	11th to 20th	Day	42% 8% 13% 21% 14% 1	2470
	21st to end	Day	41% 9% 15% 20% 14% 1	2470
July	1st to 10th	Day	40% 7% 13% 22% 16% 2	4055
	11th to 20th	Day	33% 7% 12% 31% 16% 1	4051
	21st to end	Day	44% 7% 11% 18% 17% 3	4324
August	1st to 10th	Day	40% 8% 15% 26% 10%	4091
	11th to 20th	Day	37% 9% 11% 30% 13%	4083
	21st to end	Day	30% 8% 15% 30% 13% 3	4468
September	1st to 10th	Day	36% 6% 11% 23% 21% 3	2119
	11th to 20th	Day	32% 6% 13% 26% 20% 3	2090
	21st to end	Day	45% 5% 10% 22% 17% 1	2090
October	1st to 10th	Day	39% 7% 11% 23% 20% 1	1994
	11th to 20th	Day	42% 5% 13% 24% 15% 1	1900
	21st to end	Day	49% 5% 12% 21% 12% 2	2027
November	1st to 10th	Day	38% 5% 10% 29% 16% 3	1677
	11th to 20th	Day	50% 5% 9% 21% 12% 3	1710
	21st to end	Day	54% 6% 10% 19% 10% 1	1710
December	1st to 10th	Day	67% 4 11% 14% 3	1520
	11th to 20th	Day	63% 4 9% 17% 6%	2078
	21st to end	Day	73% 5% 11% 8% 3	3124
January	1st to 10th	Night	68% 5% 9% 14% 4	4109
	11th to 20th	Night	71% 5% 11% 11% 2	4120
	21st to end	Night	74% 2 7% 13% 3 1	4532
February	1st to 10th	Night	60% 5% 10% 18% 8% 1	2470
	11th to 20th	Night	60% 5% 8% 17% 9% 1	2290
	21st to end	Night	61% 4 9% 15% 9% 2	1884
March	1st to 10th	Night	53% 4 8% 24% 11%	3514
	11th to 20th	Night	45% 6% 12% 28% 8% 1	3480
	21st to end	Night	45% 5% 8% 27% 13% 1	3817
April	1st to 10th	Night	46% 5% 11% 22% 14% 2	2090
	11th to 20th	Night	43% 6% 11% 19% 18% 4	1726
	21st to end	Night	43% 7% 12% 21% 15% 2	1710
May	1st to 10th	Night	57% 6% 9% 18% 8% 2	2840
	11th to 20th	Night	46% 7% 9% 26% 12% 2	2813
	21st to end	Night	34% 8% 15% 26% 13% 4	3087
June	1st to 10th	Night	36% 7% 12% 24% 18% 2	1710
	11th to 20th	Night	33% 7% 16% 24% 17% 3	1710
	21st to end	Night	34% 9% 14% 25% 16% 3	1710
July	1st to 10th	Night	37% 6% 11% 23% 18% 5%	2795
	11th to 20th	Night	34% 8% 13% 29% 15% 2	2786
	21st to end	Night	39% 8% 13% 20% 16% 3	2988
August	1st to 10th	Night	40% 9% 15% 25% 12% 1	2814
	11th to 20th	Night	39% 7% 9% 23% 21% 1	2812
	21st to end	Night	28% 8% 15% 29% 17% 3	3155
September	1st to 10th	Night	33% 6% 11% 22% 22% 7%	2057
	11th to 20th	Night	28% 5% 12% 27% 25% 3	2090
	21st to end	Night	41% 4 10% 21% 22% 2	2090
October	1st to 10th	Night	35% 5% 11% 26% 21% 2	2185
	11th to 20th	Night	40% 5% 11% 25% 17% 2	2280
	21st to end	Night	47% 4 9% 23% 15% 2	2435
November	1st to 10th	Night	38% 4 12% 25% 18% 4	2399
	11th to 20th	Night	48% 5% 9% 20% 15% 2	2470
	21st to end	Night	54% 5% 11% 20% 8% 1	2470
December	1st to 10th	Night	63% 5% 9% 17% 5%	2648
	11th to 20th	Night	58% 5% 12% 19% 5%	3101
	21st to end	Night	69% 5% 10% 12% 3	4532

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	31% 21% 33% 9% 4	270
	11th to 20th	Day	33% 24% 35% 6% 1	270
	21st to end	Day	35% 26% 29% 9% 1	297
February	1st to 10th	Day	37% 23% 29% 9% 3	270
	11th to 20th	Day	38% 26% 28% 7% 1	270
	21st to end	Day	34% 28% 34% 3 1	225
March	1st to 10th	Day	28% 23% 30% 14% 5%	398
	11th to 20th	Day	30% 19% 30% 14% 6% 1	460
	21st to end	Day	33% 19% 30% 15% 4	506
April	1st to 10th	Day	27% 19% 30% 14% 7% 3	460
	11th to 20th	Day	29% 17% 28% 16% 8% 3	452
	21st to end	Day	25% 19% 34% 15% 5% 2	460
May	1st to 10th	Day	29% 17% 27% 16% 7% 3	463
	11th to 20th	Day	24% 10% 30% 21% 11% 4	487
	21st to end	Day	13% 10% 28% 26% 18% 5%	529
June	1st to 10th	Day	15% 9% 32% 26% 12% 5%	490
	11th to 20th	Day	17% 10% 24% 29% 15% 6%	490
	21st to end	Day	14% 8% 30% 28% 14% 7%	490
July	1st to 10th	Day	14% 5% 19% 26% 20% 15%	485
	11th to 20th	Day	12% 5% 23% 29% 22% 9%	484
	21st to end	Day	15% 5% 22% 27% 21% 10%	532
August	1st to 10th	Day	12% 4 21% 30% 20% 12%	486
	11th to 20th	Day	13% 5% 22% 31% 19% 9%	479
	21st to end	Day	9% 5% 20% 27% 27% 13%	539
September	1st to 10th	Day	15% 5% 21% 26% 23% 9%	490
	11th to 20th	Day	10% 4 16% 27% 30% 12%	490
	21st to end	Day	26% 11% 19% 23% 16% 5%	490
October	1st to 10th	Day	13% 11% 27% 26% 19% 5%	490
	11th to 20th	Day	18% 15% 31% 22% 12% 3	490
	21st to end	Day	28% 15% 30% 18% 8% 1	514
November	1st to 10th	Day	18% 20% 34% 16% 9% 3	275
	11th to 20th	Day	31% 16% 30% 15% 7% 1	270
	21st to end	Day	27% 22% 33% 15% 3	270
December	1st to 10th	Day	33% 21% 29% 12% 3 2	180
	11th to 20th	Day	29% 29% 29% 9% 4	236
	21st to end	Day	36% 19% 31% 11% 3	297
January	1st to 10th	Night	28% 21% 30% 18% 4	760
	11th to 20th	Night	31% 19% 31% 17% 3	760
	21st to end	Night	31% 19% 29% 19% 2	836
February	1st to 10th	Night	32% 15% 29% 22% 3	760
	11th to 20th	Night	29% 20% 32% 18% 1	743
	21st to end	Night	31% 16% 32% 18% 3	628
March	1st to 10th	Night	24% 18% 30% 24% 3	760
	11th to 20th	Night	25% 18% 27% 23% 6% 1	760
	21st to end	Night	26% 14% 32% 21% 6%	836
April	1st to 10th	Night	24% 15% 33% 21% 6%	760
	11th to 20th	Night	20% 13% 34% 22% 10% 1	602
	21st to end	Night	19% 12% 36% 28% 6%	570
May	1st to 10th	Night	22% 11% 26% 28% 11% 1	570
	11th to 20th	Night	19% 6% 30% 29% 13% 2	561
	21st to end	Night	11% 5% 22% 35% 24% 2	617
June	1st to 10th	Night	11% 4 26% 36% 21% 1	570
	11th to 20th	Night	12% 5% 20% 39% 22% 2	570
	21st to end	Night	13% 3 22% 37% 22% 2	570
July	1st to 10th	Night	10% 3 17% 35% 29% 6%	555
	11th to 20th	Night	8% 3 19% 34% 33% 4	552
	21st to end	Night	8% 4 16% 37% 33% 3	624
August	1st to 10th	Night	7% 2 15% 36% 35% 4	567
	11th to 20th	Night	10% 4 13% 37% 32% 4	564
	21st to end	Night	9% 2 18% 30% 34% 7%	645
September	1st to 10th	Night	15% 3 16% 34% 26% 6%	760
	11th to 20th	Night	10% 3 14% 34% 33% 5%	760
	21st to end	Night	19% 6% 23% 28% 20% 3	760
October	1st to 10th	Night	16% 6% 22% 31% 23% 3	760
	11th to 20th	Night	19% 11% 29% 26% 14% 1	760
	21st to end	Night	25% 12% 27% 27% 9% 1	812
November	1st to 10th	Night	19% 11% 26% 27% 16%	740
	11th to 20th	Night	24% 15% 27% 25% 8% 1	760
	21st to end	Night	26% 15% 27% 25% 6% 1	760
December	1st to 10th	Night	34% 16% 28% 18% 4	760
	11th to 20th	Night	27% 18% 30% 22% 4	760
	21st to end	Night	31% 15% 30% 22% 2	836

Page generated at 2024-10-22 20:21:05. Version ac07

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