Millersburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Millersburg clear sky chart from 2005-11-06 to 2024-03-23.

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% 8% 3 6% 5% 3 5% 5% 5% 7% 37%	79291
	Night	15% 8% 3 6% 5% 3 4 4 5% 7% 38%	80578
Transparency	Day	45% 7% 11% 21% 13% 2	79014
	Night	44% 7% 11% 20% 14% 3	80375
Seeing	Day	18% 12% 25% 22% 15% 7%	14074
	Night	18% 10% 25% 29% 16% 2	24028

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	16% 14% 6% 8% 6% 3 5% 5% 6% 7% 25%	2836
	11th to 20th	Day	17% 12% 6% 14% 7% 4 4 3 4 4 26%	2840
	21st to end	Day	27% 15% 8% 6% 5% 2 3 3 3 5% 22%	3124
February	1st to 10th	Day	19% 11% 5% 9% 6% 3 4 4 4 6% 30%	1819
	11th to 20th	Day	19% 10% 4 8% 6% 3 5% 4 5% 5% 32%	1848
	21st to end	Day	20% 10% 4 7% 5% 3 4 4 6% 5% 31%	1570
March	1st to 10th	Day	20% 10% 3 5% 5% 3 3 5% 4 6% 36%	1933
	11th to 20th	Day	20% 8% 3 6% 6% 3 4 4 5% 6% 34%	2090
	21st to end	Day	19% 9% 4 7% 6% 4 5% 4 5% 6% 32%	2200
April	1st to 10th	Day	14% 8% 4 7% 5% 3 4 5% 5% 7% 39%	2088
	11th to 20th	Day	17% 8% 3 5% 5% 3 4 4 5% 7% 39%	2181
	21st to end	Day	18% 7% 3 6% 6% 4 5% 4 5% 8% 36%	2340
May	1st to 10th	Day	20% 6% 3 5% 5% 3 6% 5% 5% 7% 35%	2340
	11th to 20th	Day	18% 7% 4 7% 5% 3 4 5% 5% 7% 36%	2301
	21st to end	Day	8% 6% 3 6% 6% 4 6% 6% 7% 10% 39%	2531
June	1st to 10th	Day	11% 4 2 5% 6% 4 5% 5% 6% 8% 43%	2340
	11th to 20th	Day	9% 5% 2 5% 6% 3 6% 5% 7% 8% 43%	2340
	21st to end	Day	9% 5% 3 6% 5% 3 6% 5% 7% 10% 41%	2485
July	1st to 10th	Day	13% 6% 2 5% 5% 4 6% 6% 7% 10% 36%	2422
	11th to 20th	Day	9% 6% 3 5% 6% 4 7% 6% 7% 10% 39%	2340
	21st to end	Day	12% 5% 3 6% 6% 4 6% 6% 6% 8% 39%	2547
August	1st to 10th	Day	11% 5% 2 6% 5% 4 5% 6% 7% 10% 41%	2327
	11th to 20th	Day	9% 6% 2 6% 6% 4 6% 5% 8% 11% 36%	2303
	21st to end	Day	8% 5% 2 5% 6% 3 6% 6% 6% 10% 43%	2392
September	1st to 10th	Day	16% 5% 2 5% 5% 2 5% 4 6% 8% 43%	2026
	11th to 20th	Day	11% 5% 2 5% 5% 3 4 5% 5% 8% 48%	1980
	21st to end	Day	13% 6% 2 5% 4 3 3 4 4 7% 49%	1980
October	1st to 10th	Day	12% 5% 2 4 4 2 4 4 5% 7% 52%	1980
	11th to 20th	Day	15% 5% 2 5% 4 3 3 4 4 7% 48%	1823
	21st to end	Day	19% 8% 3 4 5% 3 3 3 5% 6% 42%	1886
November	1st to 10th	Day	12% 5% 2 4 4 3 3 3 4 5% 54%	1672
	11th to 20th	Day	15% 9% 3 5% 5% 3 3 4 5% 6% 42%	1710
	21st to end	Day	18% 9% 4 6% 5% 3 3 4 5% 6% 39%	1710
December	1st to 10th	Day	22% 13% 4 7% 5% 3 4 5% 4 5% 29%	1710
	11th to 20th	Day	15% 12% 4 7% 6% 4 6% 4 5% 5% 32%	2153
	21st to end	Day	19% 16% 5% 8% 7% 4 5% 4 5% 6% 21%	3124
January	1st to 10th	Night	15% 14% 5% 9% 7% 3 5% 4 5% 6% 26%	4109
	11th to 20th	Night	17% 13% 6% 11% 7% 3 4 4 4 4 28%	4120
	21st to end	Night	25% 14% 5% 7% 5% 2 3 3 4 5% 27%	4532
February	1st to 10th	Night	22% 10% 5% 7% 5% 3 4 4 5% 5% 30%	2357
	11th to 20th	Night	19% 10% 4 7% 6% 3 4 3 4 6% 32%	2218
	21st to end	Night	21% 13% 5% 6% 6% 3 4 4 4 5% 29%	1884
March	1st to 10th	Night	18% 9% 4 6% 5% 3 4 4 4 5% 39%	2247
	11th to 20th	Night	19% 8% 3 6% 4 3 5% 4 5% 7% 38%	2090
	21st to end	Night	16% 9% 4 7% 5% 3 4 5% 6% 7% 34%	2201
April	1st to 10th	Night	12% 5% 2 6% 6% 3 5% 5% 6% 7% 42%	1886
	11th to 20th	Night	15% 5% 4 5% 5% 3 4 4 4 6% 44%	1726
	21st to end	Night	16% 7% 3 5% 4 3 5% 5% 5% 6% 40%	1620
May	1st to 10th	Night	16% 7% 3 7% 6% 4 4 5% 6% 8% 34%	1620
	11th to 20th	Night	14% 6% 3 4 6% 4 7% 7% 6% 7% 36%	1592
	21st to end	Night	7% 5% 3 5% 6% 4 6% 6% 7% 11% 41%	1744
June	1st to 10th	Night	7% 5% 2 4 5% 3 4 6% 6% 11% 47%	1620
	11th to 20th	Night	6% 4 3 4 5% 4 5% 6% 8% 10% 47%	1620
	21st to end	Night	8% 4 2 5% 4 4 6% 5% 8% 11% 45%	1461
July	1st to 10th	Night	9% 6% 2 6% 6% 4 5% 6% 6% 9% 42%	1525
	11th to 20th	Night	5% 4 2 4 5% 3 5% 6% 7% 10% 49%	1620
	21st to end	Night	9% 4 3 5% 5% 3 5% 6% 6% 8% 47%	1771
August	1st to 10th	Night	8% 4 2 4 4 3 4 5% 7% 10% 48%	1611
	11th to 20th	Night	7% 5% 2 4 5% 4 5% 7% 8% 9% 44%	1598
	21st to end	Night	7% 4 2 4 4 2 4 4 5% 9% 54%	1960
September	1st to 10th	Night	12% 5% 2 4 3 3 5% 4 5% 9% 49%	1915
	11th to 20th	Night	10% 5% 2 4 4 3 4 4 4 7% 53%	1980
	21st to end	Night	12% 5% 3 5% 5% 2 4 4 5% 6% 50%	1980
October	1st to 10th	Night	10% 4 1 4 3 2 3 4 5% 8% 55%	1980
	11th to 20th	Night	14% 6% 2 5% 5% 3 4 4 5% 7% 47%	2135
	21st to end	Night	17% 8% 2 5% 5% 3 4 4 4 6% 43%	2466
November	1st to 10th	Night	12% 6% 2 5% 4 3 4 4 4 5% 52%	2406
	11th to 20th	Night	16% 7% 3 6% 4 2 4 4 3 6% 43%	2470
	21st to end	Night	17% 10% 4 5% 4 3 4 4 5% 6% 39%	2470
December	1st to 10th	Night	22% 11% 4 6% 4 3 4 4 5% 6% 32%	2470
	11th to 20th	Night	18% 9% 4 8% 5% 3 4 4 4 7% 34%	3042
	21st to end	Night	18% 15% 4 9% 8% 4 5% 5% 5% 6% 20%	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	56% 8% 12% 16% 9% 1	2837
	11th to 20th	Day	62% 5% 8% 18% 6% 1	2840
	21st to end	Day	65% 4 7% 19% 3 1	3124
February	1st to 10th	Day	56% 5% 9% 18% 10% 2	1819
	11th to 20th	Day	54% 5% 9% 19% 10% 3	1858
	21st to end	Day	54% 6% 9% 20% 10% 3	1570
March	1st to 10th	Day	48% 6% 10% 20% 14% 2	1933
	11th to 20th	Day	50% 7% 10% 18% 12% 2	2090
	21st to end	Day	53% 7% 10% 20% 9% 2	2200
April	1st to 10th	Day	44% 6% 11% 25% 12% 3	2088
	11th to 20th	Day	44% 6% 9% 21% 15% 4	2181
	21st to end	Day	47% 7% 12% 21% 11% 2	2340
May	1st to 10th	Day	48% 7% 13% 22% 9% 2	2340
	11th to 20th	Day	49% 8% 11% 19% 12% 1	2305
	21st to end	Day	37% 11% 18% 20% 12% 1	2531
June	1st to 10th	Day	37% 9% 11% 24% 17% 1	2340
	11th to 20th	Day	36% 10% 14% 23% 16% 2	2340
	21st to end	Day	37% 9% 14% 21% 16% 3	2485
July	1st to 10th	Day	41% 11% 14% 17% 16% 2	2357
	11th to 20th	Day	38% 11% 14% 21% 14% 2	2271
	21st to end	Day	40% 9% 14% 23% 11% 3	2405
August	1st to 10th	Day	36% 10% 16% 25% 13% 1	2314
	11th to 20th	Day	39% 9% 14% 24% 12% 1	2303
	21st to end	Day	34% 10% 16% 21% 15% 4	2392
September	1st to 10th	Day	39% 8% 12% 18% 18% 5%	2026
	11th to 20th	Day	34% 8% 11% 23% 22% 3	1980
	21st to end	Day	36% 5% 9% 26% 21% 3	1980
October	1st to 10th	Day	32% 7% 12% 23% 23% 3	1980
	11th to 20th	Day	37% 5% 9% 25% 20% 4	1823
	21st to end	Day	44% 5% 10% 24% 15% 3	1886
November	1st to 10th	Day	34% 4 8% 27% 23% 4	1672
	11th to 20th	Day	43% 4 10% 21% 19% 4	1710
	21st to end	Day	46% 5% 9% 20% 17% 2	1710
December	1st to 10th	Day	57% 6% 10% 17% 9% 1	1710
	11th to 20th	Day	53% 7% 9% 17% 14% 1	2150
	21st to end	Day	61% 8% 11% 13% 6% 1	3124
January	1st to 10th	Night	56% 9% 9% 15% 10% 1	4109
	11th to 20th	Night	60% 6% 8% 17% 8% 2	4120
	21st to end	Night	60% 6% 8% 17% 8% 1	4532
February	1st to 10th	Night	56% 5% 10% 19% 9% 1	2357
	11th to 20th	Night	54% 4 9% 20% 11% 1	2219
	21st to end	Night	57% 4 12% 14% 10% 3	1884
March	1st to 10th	Night	48% 5% 7% 21% 17% 2	2247
	11th to 20th	Night	46% 6% 11% 21% 12% 2	2090
	21st to end	Night	47% 8% 12% 21% 10% 2	2201
April	1st to 10th	Night	38% 8% 12% 23% 17% 2	1886
	11th to 20th	Night	41% 5% 10% 18% 19% 6%	1726
	21st to end	Night	43% 7% 13% 21% 13% 3	1620
May	1st to 10th	Night	47% 9% 11% 20% 10% 3	1620
	11th to 20th	Night	44% 10% 12% 20% 12% 2	1593
	21st to end	Night	33% 12% 16% 20% 17% 3	1745
June	1st to 10th	Night	29% 8% 16% 27% 16% 4	1620
	11th to 20th	Night	29% 11% 15% 23% 19% 3	1620
	21st to end	Night	30% 10% 17% 22% 16% 4	1461
July	1st to 10th	Night	38% 11% 13% 18% 17% 4	1481
	11th to 20th	Night	27% 11% 17% 23% 19% 4	1566
	21st to end	Night	32% 10% 15% 27% 15% 2	1672
August	1st to 10th	Night	29% 10% 16% 26% 17% 2	1600
	11th to 20th	Night	31% 11% 16% 24% 17% 1	1598
	21st to end	Night	26% 8% 16% 27% 18% 5%	1960
September	1st to 10th	Night	32% 7% 16% 22% 17% 7%	1915
	11th to 20th	Night	31% 6% 11% 25% 24% 3	1980
	21st to end	Night	35% 6% 8% 22% 25% 3	1980
October	1st to 10th	Night	28% 7% 12% 26% 23% 5%	1980
	11th to 20th	Night	37% 5% 10% 23% 21% 4	2135
	21st to end	Night	43% 4 8% 22% 18% 4	2466
November	1st to 10th	Night	35% 4 9% 24% 24% 4	2406
	11th to 20th	Night	43% 4 9% 19% 20% 5%	2470
	21st to end	Night	46% 5% 10% 23% 14% 2	2470
December	1st to 10th	Night	53% 6% 11% 19% 11% 1	2470
	11th to 20th	Night	50% 6% 10% 21% 13% 1	3044
	21st to end	Night	61% 9% 10% 13% 6%	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	24% 22% 34% 13% 6%	270
	11th to 20th	Day	33% 24% 30% 11% 1	270
	21st to end	Day	28% 25% 34% 11% 3	297
February	1st to 10th	Day	29% 20% 33% 15% 2	270
	11th to 20th	Day	32% 26% 29% 10% 2	270
	21st to end	Day	35% 17% 39% 6% 4	225
March	1st to 10th	Day	26% 26% 31% 13% 3	303
	11th to 20th	Day	23% 24% 32% 16% 5%	460
	21st to end	Day	29% 18% 30% 15% 8%	470
April	1st to 10th	Day	18% 20% 28% 21% 10% 1	420
	11th to 20th	Day	21% 20% 27% 18% 10% 5%	412
	21st to end	Day	23% 16% 33% 16% 10% 2	420
May	1st to 10th	Day	20% 15% 32% 19% 9% 4	423
	11th to 20th	Day	17% 11% 27% 26% 13% 6%	447
	21st to end	Day	14% 7% 22% 26% 21% 10%	485
June	1st to 10th	Day	12% 7% 18% 28% 24% 10%	450
	11th to 20th	Day	11% 6% 21% 30% 24% 9%	450
	21st to end	Day	10% 5% 24% 31% 21% 9%	595
July	1st to 10th	Day	14% 5% 16% 21% 22% 22%	527
	11th to 20th	Day	11% 4 16% 24% 27% 17%	444
	21st to end	Day	11% 2 18% 28% 24% 16%	488
August	1st to 10th	Day	13% 3 16% 25% 26% 16%	446
	11th to 20th	Day	13% 4 17% 31% 23% 13%	439
	21st to end	Day	9% 5% 13% 30% 27% 18%	495
September	1st to 10th	Day	15% 4 13% 28% 26% 16%	450
	11th to 20th	Day	12% 3 14% 28% 28% 16%	450
	21st to end	Day	16% 10% 18% 24% 25% 7%	450
October	1st to 10th	Day	13% 6% 23% 30% 20% 8%	450
	11th to 20th	Day	15% 15% 29% 24% 13% 3	450
	21st to end	Day	21% 15% 30% 23% 9% 1	401
November	1st to 10th	Day	16% 14% 31% 24% 10% 4	270
	11th to 20th	Day	24% 19% 28% 21% 7% 1	270
	21st to end	Day	25% 13% 38% 18% 4 1	270
December	1st to 10th	Day	25% 23% 29% 17% 6% 1	270
	11th to 20th	Day	21% 22% 35% 17% 5%	270
	21st to end	Day	29% 20% 37% 12% 2	297
January	1st to 10th	Night	22% 19% 33% 21% 5%	760
	11th to 20th	Night	30% 17% 31% 19% 3	760
	21st to end	Night	24% 15% 35% 24% 2	836
February	1st to 10th	Night	29% 12% 34% 23% 2	760
	11th to 20th	Night	26% 17% 36% 20% 1	743
	21st to end	Night	28% 18% 35% 18% 1	628
March	1st to 10th	Night	23% 16% 33% 23% 6%	760
	11th to 20th	Night	24% 14% 34% 22% 6%	760
	21st to end	Night	21% 13% 31% 28% 7%	801
April	1st to 10th	Night	17% 13% 30% 32% 8%	626
	11th to 20th	Night	16% 13% 29% 28% 14% 1	533
	21st to end	Night	19% 9% 35% 29% 9% 1	540
May	1st to 10th	Night	18% 8% 31% 29% 13% 2	540
	11th to 20th	Night	16% 7% 21% 36% 19% 2	531
	21st to end	Night	9% 4 19% 35% 29% 4	584
June	1st to 10th	Night	8% 3 17% 42% 27% 3	540
	11th to 20th	Night	8% 2 15% 40% 30% 4	540
	21st to end	Night	8% 3 22% 37% 27% 3	540
July	1st to 10th	Night	11% 2 11% 32% 33% 10%	525
	11th to 20th	Night	6% 3 12% 34% 41% 4	522
	21st to end	Night	10% 2 10% 36% 37% 5%	591
August	1st to 10th	Night	9% 2 8% 35% 40% 6%	537
	11th to 20th	Night	7% 3 11% 37% 36% 7%	534
	21st to end	Night	8% 2 10% 32% 42% 7%	594
September	1st to 10th	Night	13% 2 13% 31% 36% 5%	655
	11th to 20th	Night	12% 3 13% 31% 34% 7%	720
	21st to end	Night	13% 5% 20% 33% 27% 3	720
October	1st to 10th	Night	11% 6% 20% 32% 27% 5%	720
	11th to 20th	Night	17% 7% 26% 33% 16% 1	720
	21st to end	Night	21% 12% 30% 25% 12% 1	792
November	1st to 10th	Night	15% 9% 26% 31% 17% 2	740
	11th to 20th	Night	20% 12% 30% 26% 11% 1	760
	21st to end	Night	23% 12% 26% 28% 10% 1	760
December	1st to 10th	Night	27% 14% 29% 24% 5%	760
	11th to 20th	Night	24% 13% 31% 26% 6% 1	760
	21st to end	Night	27% 16% 31% 23% 4	836

Page generated at 2024-03-19 23:31:08. Version ac07

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