Manheim Township Planetarium
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Manheim Township Planetarium clear sky chart from 2005-11-06 to 2024-03-01.

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% 6% 3 5% 5% 3 5% 5% 6% 8% 40%	78474
	Night	16% 6% 2 5% 5% 3 4 5% 5% 7% 42%	80928
Transparency	Day	42% 6% 12% 23% 15% 3	78187
	Night	41% 6% 12% 23% 15% 3	80750
Seeing	Day	19% 12% 26% 24% 14% 5%	13942
	Night	18% 9% 29% 31% 12% 1	23456

By Month

Percentage Cloud Cover NE (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	15% 7% 3 6% 5% 3 4 4 5% 6% 43%	2517
	11th to 20th	Day	14% 10% 4 8% 7% 4 4 4 6% 6% 32%	2710
	21st to end	Day	19% 9% 4 8% 6% 3 5% 4 4 6% 32%	3124
February	1st to 10th	Day	15% 8% 4 5% 5% 3 5% 6% 6% 7% 37%	1710
	11th to 20th	Day	16% 7% 3 5% 5% 4 4 4 5% 8% 40%	1744
	21st to end	Day	19% 10% 4 5% 4 3 5% 4 4 5% 37%	1570
March	1st to 10th	Day	12% 6% 2 5% 6% 3 5% 4 5% 7% 45%	1867
	11th to 20th	Day	16% 8% 2 5% 5% 3 6% 5% 6% 8% 37%	1980
	21st to end	Day	20% 7% 3 6% 5% 3 4 4 4 7% 38%	2257
April	1st to 10th	Day	15% 6% 3 6% 5% 3 5% 5% 6% 7% 40%	2160
	11th to 20th	Day	16% 5% 3 4 5% 3 4 4 5% 7% 44%	2134
	21st to end	Day	17% 5% 2 5% 4 3 5% 5% 7% 7% 39%	2160
May	1st to 10th	Day	16% 7% 2 6% 4 3 5% 6% 5% 8% 36%	2316
	11th to 20th	Day	20% 7% 2 5% 6% 3 5% 5% 5% 7% 37%	2478
	21st to end	Day	13% 7% 2 6% 4 3 5% 5% 6% 10% 39%	2725
June	1st to 10th	Day	12% 5% 3 5% 5% 4 6% 5% 7% 9% 40%	2520
	11th to 20th	Day	12% 6% 2 6% 5% 4 5% 6% 6% 9% 39%	2520
	21st to end	Day	10% 3 2 5% 6% 4 5% 6% 7% 10% 43%	2520
July	1st to 10th	Day	10% 5% 2 5% 6% 4 6% 7% 7% 11% 40%	2520
	11th to 20th	Day	7% 3 2 5% 6% 3 6% 7% 8% 10% 43%	2520
	21st to end	Day	10% 6% 1 6% 7% 4 6% 7% 7% 9% 37%	2618
August	1st to 10th	Day	10% 6% 2 6% 6% 4 7% 5% 7% 9% 38%	2327
	11th to 20th	Day	11% 6% 2 6% 6% 3 5% 5% 7% 9% 40%	2188
	21st to end	Day	12% 5% 2 5% 5% 4 5% 5% 6% 9% 43%	2376
September	1st to 10th	Day	16% 6% 2 5% 5% 3 5% 4 4 6% 44%	2160
	11th to 20th	Day	12% 5% 2 4 4 3 3 4 5% 8% 50%	2160
	21st to end	Day	18% 7% 3 5% 4 2 5% 5% 5% 7% 40%	1922
October	1st to 10th	Day	17% 6% 2 5% 4 2 4 4 5% 7% 43%	1800
	11th to 20th	Day	18% 5% 2 5% 4 3 4 3 4 7% 45%	1800
	21st to end	Day	17% 7% 3 4 4 2 4 4 5% 7% 43%	1976
November	1st to 10th	Day	12% 7% 2 4 4 2 3 3 4 8% 50%	1671
	11th to 20th	Day	15% 5% 2 4 4 3 4 4 5% 6% 47%	1706
	21st to end	Day	15% 5% 3 5% 5% 2 4 5% 5% 6% 44%	1520
December	1st to 10th	Day	18% 8% 3 6% 5% 2 4 5% 5% 7% 36%	1520
	11th to 20th	Day	19% 6% 3 4 4 3 5% 4 6% 8% 39%	1906
	21st to end	Day	17% 6% 3 7% 7% 4 6% 5% 5% 6% 33%	2772
January	1st to 10th	Night	15% 7% 3 5% 6% 4 4 5% 5% 7% 40%	4429
	11th to 20th	Night	18% 8% 2 5% 5% 3 4 4 5% 7% 40%	4248
	21st to end	Night	22% 9% 3 5% 5% 2 4 3 4 6% 37%	4532
February	1st to 10th	Night	17% 8% 3 5% 5% 3 5% 4 5% 6% 39%	2470
	11th to 20th	Night	17% 7% 3 6% 5% 2 4 5% 5% 5% 41%	2320
	21st to end	Night	17% 8% 3 5% 5% 3 4 5% 5% 6% 39%	1884
March	1st to 10th	Night	14% 5% 2 4 5% 3 4 4 5% 7% 47%	2085
	11th to 20th	Night	16% 7% 2 6% 4 3 4 5% 4 4 44%	1979
	21st to end	Night	18% 7% 4 5% 4 2 4 4 5% 7% 41%	2098
April	1st to 10th	Night	17% 6% 3 5% 5% 4 4 5% 5% 8% 38%	1800
	11th to 20th	Night	14% 6% 3 5% 5% 3 4 4 5% 8% 43%	1775
	21st to end	Night	19% 5% 2 5% 4 2 3 4 5% 7% 43%	1800
May	1st to 10th	Night	18% 6% 3 5% 5% 3 5% 4 6% 7% 38%	1658
	11th to 20th	Night	18% 6% 3 6% 5% 3 5% 4 5% 7% 37%	1415
	21st to end	Night	12% 7% 2 6% 5% 3 4 4 5% 10% 41%	1550
June	1st to 10th	Night	14% 5% 2 5% 4 3 5% 5% 5% 9% 43%	1440
	11th to 20th	Night	13% 5% 2 5% 5% 3 4 6% 6% 11% 40%	1440
	21st to end	Night	10% 4 2 5% 5% 2 6% 5% 7% 11% 43%	1440
July	1st to 10th	Night	8% 6% 4 7% 7% 4 6% 5% 7% 8% 38%	1440
	11th to 20th	Night	6% 3 2 5% 6% 4 6% 6% 7% 11% 45%	1440
	21st to end	Night	10% 4 2 5% 5% 4 5% 7% 7% 11% 41%	1696
August	1st to 10th	Night	9% 5% 2 4 6% 4 6% 6% 7% 9% 42%	1611
	11th to 20th	Night	11% 5% 2 6% 7% 4 4 6% 7% 7% 40%	1695
	21st to end	Night	12% 5% 2 5% 5% 3 5% 5% 7% 8% 43%	1980
September	1st to 10th	Night	14% 5% 3 5% 5% 3 3 5% 5% 6% 46%	1800
	11th to 20th	Night	12% 6% 2 3 3 2 4 4 5% 8% 51%	1800
	21st to end	Night	17% 6% 2 4 5% 4 5% 4 5% 6% 42%	2034
October	1st to 10th	Night	20% 6% 3 5% 4 2 3 3 4 6% 44%	2160
	11th to 20th	Night	15% 6% 2 5% 4 3 3 4 5% 6% 47%	2160
	21st to end	Night	18% 6% 2 3 4 2 3 4 5% 7% 46%	2377
November	1st to 10th	Night	11% 4 2 4 4 2 4 5% 5% 7% 52%	2407
	11th to 20th	Night	15% 6% 3 5% 4 3 4 4 5% 6% 46%	2473
	21st to end	Night	14% 5% 2 5% 5% 3 4 5% 5% 8% 45%	2660
December	1st to 10th	Night	19% 7% 2 5% 6% 3 5% 5% 5% 7% 37%	2660
	11th to 20th	Night	18% 5% 2 6% 5% 3 4 5% 5% 7% 40%	3288
	21st to end	Night	17% 7% 3 6% 5% 3 5% 6% 6% 7% 34%	4884

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	42% 4 14% 26% 11% 3	2518
	11th to 20th	Day	51% 4 12% 18% 13% 2	2710
	21st to end	Day	52% 5% 12% 22% 8% 1	3124
February	1st to 10th	Day	45% 5% 13% 24% 11% 2	1710
	11th to 20th	Day	44% 4 11% 24% 14% 2	1753
	21st to end	Day	49% 3 10% 22% 12% 4	1570
March	1st to 10th	Day	39% 5% 13% 26% 14% 2	1870
	11th to 20th	Day	44% 4 13% 19% 15% 5%	1980
	21st to end	Day	48% 5% 8% 20% 17% 3	2257
April	1st to 10th	Day	41% 6% 11% 21% 16% 5%	2160
	11th to 20th	Day	39% 6% 12% 23% 16% 5%	2134
	21st to end	Day	42% 7% 10% 21% 17% 4	2160
May	1st to 10th	Day	44% 6% 10% 21% 15% 3	2316
	11th to 20th	Day	46% 6% 12% 21% 13% 2	2482
	21st to end	Day	40% 9% 15% 22% 12% 2	2725
June	1st to 10th	Day	38% 8% 14% 24% 14% 1	2520
	11th to 20th	Day	40% 8% 14% 24% 12% 3	2520
	21st to end	Day	34% 8% 16% 25% 16% 1	2520
July	1st to 10th	Day	37% 9% 12% 23% 15% 3	2450
	11th to 20th	Day	32% 8% 15% 27% 16% 2	2445
	21st to end	Day	40% 9% 12% 21% 15% 2	2472
August	1st to 10th	Day	40% 9% 13% 24% 14% 1	2314
	11th to 20th	Day	39% 7% 15% 21% 17% 2	2188
	21st to end	Day	38% 7% 12% 24% 16% 3	2376
September	1st to 10th	Day	41% 5% 11% 20% 17% 5%	2160
	11th to 20th	Day	33% 5% 11% 27% 22% 4	2160
	21st to end	Day	44% 5% 9% 19% 20% 3	1922
October	1st to 10th	Day	39% 6% 13% 24% 17% 2	1800
	11th to 20th	Day	40% 5% 11% 23% 19% 2	1800
	21st to end	Day	40% 4 11% 26% 17% 2	1976
November	1st to 10th	Day	35% 3 14% 25% 19% 4	1671
	11th to 20th	Day	39% 5% 11% 23% 20% 2	1706
	21st to end	Day	41% 5% 12% 30% 11% 2	1520
December	1st to 10th	Day	47% 4 17% 19% 11% 1	1520
	11th to 20th	Day	43% 5% 13% 30% 8% 1	1906
	21st to end	Day	49% 7% 15% 19% 9% 1	2772
January	1st to 10th	Night	42% 6% 12% 26% 11% 3	4429
	11th to 20th	Night	44% 5% 13% 25% 12% 2	4248
	21st to end	Night	49% 4 10% 27% 9% 1	4532
February	1st to 10th	Night	45% 4 13% 25% 11% 2	2470
	11th to 20th	Night	44% 4 10% 21% 18% 2	2322
	21st to end	Night	46% 5% 10% 21% 15% 4	1884
March	1st to 10th	Night	36% 4 13% 26% 18% 2	2095
	11th to 20th	Night	43% 5% 11% 22% 16% 4	1980
	21st to end	Night	44% 4 9% 21% 18% 5%	2098
April	1st to 10th	Night	43% 5% 10% 20% 17% 4	1800
	11th to 20th	Night	39% 4 11% 23% 19% 4	1775
	21st to end	Night	41% 6% 9% 22% 17% 5%	1800
May	1st to 10th	Night	44% 7% 10% 20% 15% 4	1658
	11th to 20th	Night	45% 8% 11% 15% 18% 3	1416
	21st to end	Night	40% 9% 15% 19% 15% 2	1551
June	1st to 10th	Night	38% 7% 12% 22% 19% 2	1440
	11th to 20th	Night	37% 9% 15% 21% 16% 2	1440
	21st to end	Night	34% 7% 14% 27% 16% 2	1440
July	1st to 10th	Night	43% 8% 14% 18% 14% 3	1400
	11th to 20th	Night	32% 9% 16% 24% 16% 3	1392
	21st to end	Night	33% 10% 17% 21% 17% 2	1602
August	1st to 10th	Night	36% 9% 16% 25% 14% 1	1600
	11th to 20th	Night	40% 8% 15% 19% 16% 2	1695
	21st to end	Night	36% 8% 14% 21% 18% 3	1980
September	1st to 10th	Night	38% 7% 11% 22% 19% 4	1800
	11th to 20th	Night	32% 5% 10% 25% 25% 4	1800
	21st to end	Night	42% 6% 9% 19% 21% 3	2034
October	1st to 10th	Night	43% 5% 10% 24% 16% 2	2160
	11th to 20th	Night	37% 5% 11% 28% 17% 2	2160
	21st to end	Night	38% 4 10% 27% 18% 2	2377
November	1st to 10th	Night	32% 4 12% 27% 20% 4	2407
	11th to 20th	Night	39% 4 9% 25% 18% 5%	2473
	21st to end	Night	37% 5% 13% 28% 15% 2	2660
December	1st to 10th	Night	46% 5% 13% 22% 13% 1	2660
	11th to 20th	Night	43% 5% 14% 22% 14% 3	3288
	21st to end	Night	46% 7% 15% 22% 10% 1	4884

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	26% 22% 31% 18% 2 2	180
	11th to 20th	Day	26% 28% 29% 14% 3	234
	21st to end	Day	24% 23% 32% 17% 4 1	297
February	1st to 10th	Day	24% 19% 39% 14% 4	270
	11th to 20th	Day	23% 25% 38% 13% 1	351
	21st to end	Day	29% 17% 32% 18% 4	382
March	1st to 10th	Day	17% 24% 32% 23% 4	420
	11th to 20th	Day	22% 21% 34% 18% 4 1	420
	21st to end	Day	24% 17% 30% 21% 6% 2	462
April	1st to 10th	Day	21% 18% 33% 20% 6% 2	420
	11th to 20th	Day	18% 18% 27% 21% 12% 4	412
	21st to end	Day	25% 14% 31% 20% 8% 2	420
May	1st to 10th	Day	25% 16% 26% 19% 10% 3	423
	11th to 20th	Day	21% 12% 29% 21% 13% 4	447
	21st to end	Day	19% 5% 23% 25% 19% 9%	485
June	1st to 10th	Day	16% 7% 28% 26% 18% 6%	450
	11th to 20th	Day	17% 9% 24% 26% 19% 6%	450
	21st to end	Day	14% 6% 22% 34% 18% 7%	450
July	1st to 10th	Day	13% 3 16% 27% 27% 14%	445
	11th to 20th	Day	5% 2 16% 35% 30% 12%	444
	21st to end	Day	14% 3 22% 32% 23% 7%	488
August	1st to 10th	Day	12% 4 18% 29% 26% 11%	446
	11th to 20th	Day	12% 5% 16% 31% 23% 13%	439
	21st to end	Day	14% 3 15% 33% 21% 13%	495
September	1st to 10th	Day	20% 5% 18% 21% 24% 12%	450
	11th to 20th	Day	14% 4 20% 26% 22% 14%	450
	21st to end	Day	21% 10% 23% 23% 16% 7%	450
October	1st to 10th	Day	21% 6% 22% 26% 19% 6%	450
	11th to 20th	Day	18% 12% 26% 27% 15% 2	450
	21st to end	Day	18% 13% 34% 26% 8% 2	493
November	1st to 10th	Day	16% 10% 28% 27% 15% 3	365
	11th to 20th	Day	15% 17% 32% 25% 10% 1	366
	21st to end	Day	19% 21% 34% 18% 8% 1	180
December	1st to 10th	Day	24% 20% 34% 16% 4 2	180
	11th to 20th	Day	26% 21% 29% 17% 6% 1	180
	21st to end	Day	23% 17% 31% 21% 8%	198
January	1st to 10th	Night	17% 14% 44% 22% 3	760
	11th to 20th	Night	23% 14% 33% 26% 4	760
	21st to end	Night	18% 14% 42% 25% 2	836
February	1st to 10th	Night	21% 15% 36% 26% 2	760
	11th to 20th	Night	22% 18% 40% 19% 1	743
	21st to end	Night	22% 18% 37% 20% 3	628
March	1st to 10th	Night	18% 13% 40% 25% 4	723
	11th to 20th	Night	21% 15% 36% 22% 6% 1	720
	21st to end	Night	21% 10% 38% 25% 6%	792
April	1st to 10th	Night	20% 16% 36% 23% 5%	720
	11th to 20th	Night	17% 11% 34% 30% 8%	711
	21st to end	Night	22% 9% 32% 29% 8%	720
May	1st to 10th	Night	21% 7% 28% 34% 9% 1	578
	11th to 20th	Night	21% 6% 28% 35% 10%	354
	21st to end	Night	15% 4 21% 41% 19% 2	389
June	1st to 10th	Night	16% 3 23% 39% 19%	360
	11th to 20th	Night	14% 2 23% 43% 18%	360
	21st to end	Night	10% 2 19% 53% 15% 1	360
July	1st to 10th	Night	11% 2 17% 43% 25% 2	350
	11th to 20th	Night	6% 1 14% 47% 30% 2	348
	21st to end	Night	11% 2 15% 45% 26% 2	516
August	1st to 10th	Night	11% 1 11% 46% 28% 2	537
	11th to 20th	Night	13% 3 13% 38% 31% 3	631
	21st to end	Night	14% 2 14% 40% 27% 3	792
September	1st to 10th	Night	15% 4 18% 36% 23% 4	720
	11th to 20th	Night	14% 3 15% 37% 28% 4	720
	21st to end	Night	19% 3 20% 36% 21% 2	720
October	1st to 10th	Night	23% 5% 20% 31% 18% 4	720
	11th to 20th	Night	19% 7% 27% 34% 14%	720
	21st to end	Night	20% 7% 33% 28% 11%	792
November	1st to 10th	Night	13% 7% 32% 35% 13% 1	740
	11th to 20th	Night	17% 13% 29% 31% 8% 1	760
	21st to end	Night	16% 13% 34% 29% 8%	760
December	1st to 10th	Night	24% 12% 33% 24% 6% 1	760
	11th to 20th	Night	18% 12% 39% 26% 5%	760
	21st to end	Night	20% 11% 37% 30% 2	836

Page generated at 2024-02-27 06:30:17. Version ac07

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