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 2024-02-25.

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	16% 10% 4 7% 6% 3 5% 5% 5% 7% 32%	78539
	Night	16% 10% 4 7% 5% 3 4 4 5% 6% 34%	80748
Transparency	Day	51% 6% 11% 19% 11% 1	78261
	Night	50% 6% 11% 20% 12% 2	80545
Seeing	Day	22% 14% 27% 20% 12% 5%	13817
	Night	21% 11% 26% 26% 14% 2	24135

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% 20% 6% 9% 6% 3 4 4 4 5% 20%	2836
	11th to 20th	Day	15% 21% 9% 11% 7% 5% 5% 4 4 4 16%	2840
	21st to end	Day	27% 21% 7% 9% 7% 3 3 3 3 4 13%	3124
February	1st to 10th	Day	22% 14% 5% 9% 7% 3 3 3 4 4 26%	1710
	11th to 20th	Day	17% 13% 6% 11% 6% 3 4 5% 4 6% 26%	1775
	21st to end	Day	20% 12% 6% 8% 6% 3 3 3 3 6% 31%	1520
March	1st to 10th	Day	18% 11% 4 7% 7% 2 4 4 4 6% 33%	1921
	11th to 20th	Day	18% 13% 4 8% 6% 3 4 4 5% 7% 30%	1980
	21st to end	Day	22% 10% 4 8% 5% 4 4 4 5% 6% 29%	2178
April	1st to 10th	Day	15% 11% 4 7% 7% 3 4 4 4 7% 34%	1980
	11th to 20th	Day	16% 10% 3 5% 6% 3 6% 5% 5% 6% 35%	2288
	21st to end	Day	19% 7% 3 6% 6% 4 5% 5% 5% 7% 32%	2340
May	1st to 10th	Day	18% 9% 4 7% 7% 4 4 5% 6% 8% 29%	2340
	11th to 20th	Day	21% 7% 3 6% 7% 3 4 5% 5% 7% 32%	2301
	21st to end	Day	9% 5% 3 6% 6% 4 7% 6% 7% 10% 38%	2531
June	1st to 10th	Day	12% 6% 3 6% 5% 4 7% 6% 5% 9% 38%	2340
	11th to 20th	Day	12% 6% 3 6% 5% 4 6% 6% 7% 10% 34%	2340
	21st to end	Day	12% 5% 2 5% 6% 4 5% 7% 8% 9% 36%	2340
July	1st to 10th	Day	11% 6% 3 6% 5% 4 6% 6% 6% 10% 35%	2340
	11th to 20th	Day	10% 6% 3 6% 5% 3 6% 6% 7% 8% 41%	2340
	21st to end	Day	11% 6% 3 5% 5% 5% 7% 6% 7% 9% 36%	2547
August	1st to 10th	Day	9% 6% 2 6% 6% 4 6% 7% 8% 10% 36%	2327
	11th to 20th	Day	10% 6% 2 6% 6% 3 7% 8% 8% 10% 33%	2303
	21st to end	Day	9% 5% 2 5% 7% 4 5% 6% 6% 9% 42%	2538
September	1st to 10th	Day	14% 6% 2 5% 4 2 4 4 6% 8% 45%	2008
	11th to 20th	Day	9% 5% 2 5% 5% 3 5% 5% 6% 9% 46%	1980
	21st to end	Day	18% 7% 3 5% 4 3 4 4 5% 6% 41%	1980
October	1st to 10th	Day	14% 7% 2 6% 4 3 4 4 6% 8% 41%	1890
	11th to 20th	Day	16% 7% 2 6% 4 3 5% 4 6% 7% 40%	1800
	21st to end	Day	21% 10% 3 6% 5% 3 3 4 4 6% 35%	1980
November	1st to 10th	Day	11% 7% 3 6% 5% 2 3 3 5% 7% 47%	1677
	11th to 20th	Day	17% 12% 4 6% 4 2 4 4 5% 6% 35%	1710
	21st to end	Day	18% 13% 4 7% 5% 3 5% 4 5% 5% 31%	1710
December	1st to 10th	Day	23% 14% 8% 9% 6% 2 5% 4 4 5% 20%	1520
	11th to 20th	Day	18% 16% 6% 10% 5% 3 5% 4 5% 5% 22%	2081
	21st to end	Day	23% 22% 5% 9% 7% 4 5% 4 4 5% 14%	3124
January	1st to 10th	Night	16% 19% 8% 11% 7% 4 4 4 4 4 19%	4109
	11th to 20th	Night	15% 17% 7% 14% 7% 4 6% 5% 4 4 16%	4120
	21st to end	Night	27% 17% 8% 10% 7% 2 3 2 3 3 17%	4532
February	1st to 10th	Night	21% 14% 4 7% 6% 3 4 4 4 5% 28%	2470
	11th to 20th	Night	19% 12% 4 9% 8% 4 5% 4 4 6% 26%	2288
	21st to end	Night	20% 14% 7% 8% 5% 4 4 3 3 4 27%	1831
March	1st to 10th	Night	16% 10% 4 7% 6% 4 4 4 4 5% 36%	2039
	11th to 20th	Night	17% 10% 4 6% 5% 3 4 4 5% 7% 34%	1980
	21st to end	Night	21% 8% 3 7% 5% 3 4 3 4 7% 35%	2178
April	1st to 10th	Night	16% 10% 3 5% 4 2 5% 5% 5% 6% 38%	1980
	11th to 20th	Night	15% 7% 3 5% 4 3 5% 5% 6% 8% 38%	1634
	21st to end	Night	16% 8% 2 6% 5% 3 4 5% 6% 9% 36%	1620
May	1st to 10th	Night	18% 7% 3 7% 6% 4 5% 5% 6% 8% 32%	1620
	11th to 20th	Night	16% 8% 3 7% 5% 4 5% 4 5% 7% 37%	1592
	21st to end	Night	8% 6% 3 5% 6% 3 5% 6% 6% 10% 42%	1744
June	1st to 10th	Night	9% 6% 2 5% 5% 3 5% 5% 4 8% 47%	1620
	11th to 20th	Night	9% 6% 2 5% 5% 4 5% 5% 6% 11% 43%	1620
	21st to end	Night	12% 4 2 4 4 3 5% 7% 5% 9% 46%	1620
July	1st to 10th	Night	9% 6% 3 5% 4 3 4 4 6% 8% 47%	1620
	11th to 20th	Night	7% 5% 1 6% 5% 3 4 6% 6% 10% 47%	1620
	21st to end	Night	7% 6% 3 5% 7% 3 6% 6% 8% 10% 40%	1771
August	1st to 10th	Night	5% 5% 2 5% 6% 4 5% 6% 8% 10% 43%	1611
	11th to 20th	Night	9% 5% 3 7% 6% 4 5% 6% 5% 8% 44%	1598
	21st to end	Night	8% 4 2 4 4 3 4 5% 6% 9% 49%	1799
September	1st to 10th	Night	13% 4 1 5% 4 3 4 4 5% 6% 52%	1948
	11th to 20th	Night	10% 4 2 3 4 2 4 4 5% 7% 55%	1980
	21st to end	Night	16% 6% 3 4 4 3 4 4 4 6% 47%	1980
October	1st to 10th	Night	12% 5% 2 5% 4 3 4 4 5% 8% 47%	2070
	11th to 20th	Night	15% 7% 3 5% 4 3 5% 6% 5% 7% 40%	2160
	21st to end	Night	22% 7% 3 6% 4 3 3 4 4 6% 37%	2376
November	1st to 10th	Night	14% 7% 3 5% 4 2 3 4 4 6% 48%	2399
	11th to 20th	Night	16% 10% 3 6% 5% 3 5% 5% 4 6% 36%	2470
	21st to end	Night	20% 11% 4 7% 5% 3 4 4 5% 6% 30%	2470
December	1st to 10th	Night	23% 14% 6% 8% 6% 3 4 4 4 5% 23%	2648
	11th to 20th	Night	18% 15% 6% 8% 6% 3 3 4 5% 6% 26%	3099
	21st to end	Night	22% 19% 6% 9% 7% 4 4 4 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	57% 5% 10% 18% 8% 2	1520
March	1st to 10th	Day	52% 4 11% 23% 8% 1	1921
	11th to 20th	Day	55% 5% 10% 19% 10% 2	1980
	21st to end	Day	55% 5% 10% 20% 10% 1	2178
April	1st to 10th	Day	51% 5% 10% 19% 12% 2	1980
	11th to 20th	Day	48% 6% 11% 16% 16% 3	2288
	21st to end	Day	50% 7% 9% 21% 11% 2	2340
May	1st to 10th	Day	53% 6% 12% 19% 9% 2	2340
	11th to 20th	Day	52% 6% 12% 17% 11% 2	2305
	21st to end	Day	39% 10% 15% 24% 11% 1	2531
June	1st to 10th	Day	42% 7% 11% 23% 15% 1	2340
	11th to 20th	Day	43% 8% 13% 21% 14% 1	2340
	21st to end	Day	41% 9% 15% 20% 14% 1	2340
July	1st to 10th	Day	42% 9% 13% 20% 14% 1	2275
	11th to 20th	Day	40% 8% 12% 24% 14% 1	2271
	21st to end	Day	40% 8% 13% 24% 12% 2	2405
August	1st to 10th	Day	38% 9% 15% 25% 12% 1	2314
	11th to 20th	Day	40% 9% 14% 25% 11% 1	2303
	21st to end	Day	35% 8% 14% 24% 15% 4	2538
September	1st to 10th	Day	38% 6% 11% 23% 19% 3	2008
	11th to 20th	Day	33% 6% 13% 27% 18% 2	1980
	21st to end	Day	43% 5% 10% 23% 18% 1	1980
October	1st to 10th	Day	40% 7% 12% 22% 19% 1	1890
	11th to 20th	Day	43% 5% 13% 23% 15% 1	1800
	21st to end	Day	51% 5% 12% 21% 11% 2	1980
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	1831
March	1st to 10th	Night	51% 5% 8% 22% 13% 1	2039
	11th to 20th	Night	48% 5% 12% 23% 10% 2	1980
	21st to end	Night	51% 4 9% 20% 13% 2	2178
April	1st to 10th	Night	45% 5% 11% 22% 15% 2	1980
	11th to 20th	Night	43% 5% 11% 19% 18% 4	1634
	21st to end	Night	44% 7% 12% 21% 15% 2	1620
May	1st to 10th	Night	50% 7% 12% 18% 10% 3	1620
	11th to 20th	Night	47% 7% 9% 21% 12% 3	1593
	21st to end	Night	34% 9% 17% 25% 13% 2	1745
June	1st to 10th	Night	36% 7% 12% 25% 18% 3	1620
	11th to 20th	Night	34% 7% 16% 23% 17% 3	1620
	21st to end	Night	33% 9% 14% 26% 16% 3	1620
July	1st to 10th	Night	35% 8% 12% 23% 20% 3	1575
	11th to 20th	Night	31% 8% 15% 26% 17% 3	1566
	21st to end	Night	36% 10% 14% 24% 15% 2	1672
August	1st to 10th	Night	32% 9% 15% 28% 16% 1	1600
	11th to 20th	Night	36% 9% 13% 23% 17% 2	1598
	21st to end	Night	30% 6% 14% 26% 18% 5%	1799
September	1st to 10th	Night	33% 6% 12% 22% 21% 7%	1948
	11th to 20th	Night	28% 6% 12% 27% 24% 2	1980
	21st to end	Night	39% 4 11% 22% 23% 2	1980
October	1st to 10th	Night	36% 6% 11% 25% 20% 2	2070
	11th to 20th	Night	42% 5% 11% 25% 16% 1	2160
	21st to end	Night	49% 4 9% 23% 13% 2	2376
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% 26% 37% 3	210
March	1st to 10th	Day	29% 24% 30% 14% 4	361
	11th to 20th	Day	29% 19% 31% 13% 7% 1	420
	21st to end	Day	33% 18% 29% 15% 4	462
April	1st to 10th	Day	27% 18% 30% 15% 7% 3	420
	11th to 20th	Day	28% 17% 28% 15% 8% 4	412
	21st to end	Day	26% 19% 34% 14% 5% 2	420
May	1st to 10th	Day	30% 17% 27% 16% 7% 3	423
	11th to 20th	Day	24% 10% 31% 21% 10% 4	447
	21st to end	Day	13% 9% 27% 26% 18% 6%	485
June	1st to 10th	Day	15% 7% 34% 27% 12% 5%	450
	11th to 20th	Day	18% 10% 24% 27% 15% 6%	450
	21st to end	Day	13% 8% 29% 29% 14% 6%	450
July	1st to 10th	Day	15% 5% 17% 26% 21% 17%	445
	11th to 20th	Day	13% 5% 22% 29% 21% 10%	444
	21st to end	Day	15% 5% 22% 27% 21% 10%	488
August	1st to 10th	Day	12% 4 20% 31% 21% 13%	446
	11th to 20th	Day	14% 5% 21% 31% 19% 10%	439
	21st to end	Day	10% 5% 22% 26% 25% 12%	495
September	1st to 10th	Day	16% 5% 22% 25% 23% 10%	450
	11th to 20th	Day	11% 5% 17% 26% 29% 12%	450
	21st to end	Day	23% 11% 20% 24% 17% 5%	450
October	1st to 10th	Day	14% 11% 27% 25% 18% 5%	450
	11th to 20th	Day	19% 15% 31% 23% 11% 1	450
	21st to end	Day	29% 15% 30% 18% 7% 1	495
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	611
March	1st to 10th	Night	24% 19% 31% 23% 3	720
	11th to 20th	Night	25% 18% 27% 23% 7% 1	720
	21st to end	Night	26% 14% 31% 22% 6% 1	792
April	1st to 10th	Night	24% 15% 33% 22% 7%	720
	11th to 20th	Night	20% 13% 34% 22% 11% 1	570
	21st to end	Night	19% 12% 35% 28% 6%	540
May	1st to 10th	Night	22% 10% 27% 28% 11% 1	540
	11th to 20th	Night	20% 5% 30% 29% 13% 2	531
	21st to end	Night	10% 5% 22% 35% 25% 3	584
June	1st to 10th	Night	11% 4 26% 37% 21% 1	540
	11th to 20th	Night	13% 5% 21% 38% 21% 2	540
	21st to end	Night	13% 3 21% 37% 23% 2	540
July	1st to 10th	Night	11% 3 16% 35% 30% 6%	525
	11th to 20th	Night	8% 3 19% 33% 33% 4	522
	21st to end	Night	9% 3 16% 36% 34% 3	591
August	1st to 10th	Night	7% 2 15% 37% 35% 4	537
	11th to 20th	Night	10% 3 13% 36% 33% 5%	534
	21st to end	Night	10% 2 19% 29% 34% 6%	611
September	1st to 10th	Night	15% 3 16% 33% 27% 6%	720
	11th to 20th	Night	11% 4 15% 33% 33% 5%	720
	21st to end	Night	18% 6% 23% 28% 21% 3	720
October	1st to 10th	Night	16% 7% 22% 31% 23% 3	720
	11th to 20th	Night	20% 11% 30% 26% 13% 1	720
	21st to end	Night	26% 12% 27% 27% 9%	792
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 2024-02-22 06:05:43. Version ac07

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