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 2005-11-05 to

2017-09-12
.

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 TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(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

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
38%
15087
20%
46822
11%
15050
48%
15050
25%
29667

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
24%
719
20%
2494
10%
716
39%
716
18%
1594
January16th to endNight
21%
768
22%
2496
7%
768
40%
768
22%
1555
February1st to 15thNight
19%
704
17%
2287
5%
701
35%
701
19%
1470
February16th to endNight
19%
631
23%
1900
6%
631
39%
631
21%
1220
March1st to 15thNight
26%
720
20%
2052
8%
720
39%
720
24%
1334
March16th to endNight
28%
768
21%
2058
9%
768
38%
768
27%
1372
April1st to 15thNight
27%
718
19%
1796
5%
718
34%
718
28%
1206
April16th to endNight
37%
720
18%
1800
7%
720
42%
720
30%
1210
May1st to 15thNight
40%
504
17%
1584
10%
504
47%
504
22%
1055
May16th to endNight
51%
374
16%
1497
16%
374
57%
374
20%
926
June1st to 15thNight
53%
360
17%
1440
18%
360
61%
360
23%
839
June16th to endNight
57%
360
17%
1440
21%
360
62%
360
26%
825
July1st to 15thNight
55%
340
12%
1360
15%
340
57%
340
18%
869
July16th to endNight
69%
456
15%
1492
15%
428
73%
428
30%
859
August1st to 15thNight
67%
545
19%
1615
15%
542
69%
542
31%
990
August16th to endNight
64%
764
19%
1910
11%
764
66%
764
36%
1219
September1st to 15thNight
52%
707
24%
1768
12%
707
57%
707
35%
1146
September16th to endNight
57%
657
24%
1793
19%
657
60%
657
31%
1167
October1st to 15thNight
44%
660
23%
1980
19%
660
51%
660
26%
1257
October16th to endNight
37%
704
25%
2113
14%
704
51%
704
31%
1254
November1st to 15thNight
38%
700
23%
2277
13%
700
51%
700
27%
1378
November16th to endNight
32%
720
20%
2462
12%
720
43%
720
20%
1524
December1st to 15thNight
25%
720
16%
2520
7%
720
38%
720
17%
1667
December16th to endNight
22%
768
18%
2688
4%
768
38%
768
18%
1731

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 ForecastData
Points
Cloud CoverDay
14%5%25%43445%7%40%
47835
Night
14%5%2442445%7%42%
46999
Cloud CoverDay
14%5%25%42445%8%40%
47845
Night
14%5%2442445%7%42%
47004
TransparencyDay
41%6%12%22%14%2
47531
Night
40%5%12%22%16%2
46822
SeeingDay
18%8%23%25%16%7%
5657
Night
17%8%29%30%12%1
15089

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
15%7%26%5%3445%7%38%
1442
16th to endDay
13%8%36%5%2435%7%37%
1728
February1st to 15thDay
14%7%35%4246%6%7%37%
1575
16th to endDay
14%8%345%34447%38%
1572
March1st to 15thDay
14%6%145%36%5%5%6%39%
1895
16th to endDay
18%6%25%5%23347%39%
2166
April1st to 15thDay
18%5%25%424446%42%
2152
16th to endDay
15%42442445%6%45%
2160
May1st to 15thDay
17%6%25%425%5%5%7%36%
2376
16th to endDay
14%7%25%4245%6%9%37%
2618
June1st to 15thDay
12%424436%5%6%9%39%
2520
16th to endDay
10%425%5%345%6%9%41%
2520
July1st to 15thDay
9%425%6%36%6%6%10%38%
2520
16th to endDay
8%415%7%37%7%7%9%39%
2571
August1st to 15thDay
11%6%15%5%45%5%6%9%38%
2322
16th to endDay
11%425%42445%8%44%
2292
September1st to 15thDay
14%5%24325%346%46%
2112
16th to endDay
14%6%24424436%44%
1833
October1st to 15thDay
17%5%24323346%46%
1650
16th to endDay
16%5%24323448%42%
1757
November1st to 15thDay
13%7%34423347%46%
1581
16th to endDay
17%5%35%5%2435%6%42%
1497
December1st to 15thDay
17%6%245%25%45%7%36%
1440
16th to endDay
18%5%345%35%35%7%38%
1536
January1st to 15thNight
16%6%25%5%3345%7%38%
2494
16th to endNight
15%7%34414347%42%
2496
February1st to 15thNight
14%8%35%5%24446%40%
2285
16th to endNight
14%6%245%335%5%443%
1900
March1st to 15thNight
16%6%245%25%345%43%
2040
16th to endNight
17%5%24424345%43%
2058
April1st to 15thNight
16%5%2443345%9%40%
1796
16th to endNight
16%5%25%423447%44%
1800
May1st to 15thNight
17%5%35%424446%39%
1584
16th to endNight
13%6%25%5%2445%9%41%
1495
June1st to 15thNight
13%42332445%10%43%
1440
16th to endNight
10%425%425%5%6%11%41%
1440
July1st to 15thNight
8%5%37%6%46%46%8%38%
1440
16th to endNight
8%3145%35%6%6%11%44%
1594
August1st to 15thNight
8%5%245%345%7%8%44%
1626
16th to endNight
11%32443346%6%48%
1910
September1st to 15thNight
14%5%2442345%6%47%
1768
16th to endNight
13%5%24435%35%6%45%
1793
October1st to 15thNight
17%7%24322335%45%
1980
16th to endNight
16%5%12322446%49%
2113
November1st to 15thNight
13%5%25%423435%48%
2277
16th to endNight
16%5%24435%45%7%40%
2462
December1st to 15thNight
18%5%25%6%35%6%5%6%35%
2520
16th to endNight
17%6%25%42445%7%38%
2688

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
15%7%25%5%4445%7%38%
1442
16th to endDay
13%9%36%5%2435%7%38%
1728
February1st to 15thDay
14%7%35%4246%6%7%37%
1575
16th to endDay
15%7%35%5%34447%38%
1572
March1st to 15thDay
14%6%245%36%5%5%6%39%
1906
16th to endDay
19%6%25%5%23347%39%
2165
April1st to 15thDay
17%5%25%42445%6%42%
2152
16th to endDay
15%42442445%6%44%
2160
May1st to 15thDay
17%6%25%425%5%5%8%36%
2376
16th to endDay
14%6%25%4245%6%9%37%
2618
June1st to 15thDay
12%424436%5%6%9%39%
2520
16th to endDay
10%425%5%346%6%10%41%
2520
July1st to 15thDay
9%425%6%36%7%6%10%38%
2520
16th to endDay
7%415%6%36%7%7%9%39%
2571
August1st to 15thDay
11%6%245%35%5%6%9%38%
2322
16th to endDay
11%42443445%8%44%
2292
September1st to 15thDay
14%5%24325%347%46%
2112
16th to endDay
13%6%24424446%44%
1833
October1st to 15thDay
17%6%14413346%46%
1650
16th to endDay
16%5%24323447%43%
1757
November1st to 15thDay
13%7%33423347%46%
1581
16th to endDay
17%5%35%424346%42%
1497
December1st to 15thDay
17%6%25%425%45%7%36%
1440
16th to endDay
18%5%345%35%347%38%
1536
January1st to 15thNight
16%7%25%5%3345%7%38%
2494
16th to endNight
16%7%24423347%42%
2496
February1st to 15thNight
14%7%35%5%24446%40%
2278
16th to endNight
14%6%245%335%5%5%43%
1900
March1st to 15thNight
16%6%245%25%345%43%
2052
16th to endNight
17%5%34424346%43%
2058
April1st to 15thNight
16%5%2443435%9%40%
1796
16th to endNight
15%5%25%42345%6%44%
1800
May1st to 15thNight
17%5%35%424447%39%
1584
16th to endNight
13%5%25%42445%9%41%
1495
June1st to 15thNight
13%42442445%10%43%
1440
16th to endNight
10%425%425%5%6%11%41%
1440
July1st to 15thNight
8%437%7%46%46%9%38%
1440
16th to endNight
7%3245%25%6%6%11%44%
1594
August1st to 15thNight
9%4145%345%7%8%44%
1626
16th to endNight
11%32442446%6%48%
1910
September1st to 15thNight
14%5%1442345%6%47%
1768
16th to endNight
13%5%2443445%6%45%
1793
October1st to 15thNight
17%7%24322335%45%
1980
16th to endNight
16%5%12323447%49%
2113
November1st to 15thNight
13%5%25%423335%48%
2277
16th to endNight
15%6%24435%45%7%40%
2462
December1st to 15thNight
18%5%25%6%35%6%5%6%35%
2520
16th to endNight
17%6%25%4245%5%7%37%
2688

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
45%414%21%11%3
1443
16th to endDay
45%413%22%11%2
1728
February1st to 15thDay
44%5%13%23%10%2
1577
16th to endDay
45%313%24%11%1
1572
March1st to 15thDay
44%414%22%12%1
1906
16th to endDay
45%410%20%17%1
2166
April1st to 15thDay
41%5%10%23%15%3
2152
16th to endDay
38%6%9%20%20%5%
2160
May1st to 15thDay
44%6%11%21%14%1
2376
16th to endDay
42%8%13%21%12%1
2622
June1st to 15thDay
39%8%14%25%12%
2520
16th to endDay
36%8%15%24%13%1
2520
July1st to 15thDay
39%8%11%22%15%2
2371
16th to endDay
36%8%14%24%14%1
2411
August1st to 15thDay
40%7%13%20%17%1
2309
16th to endDay
36%6%11%25%18%2
2292
September1st to 15thDay
37%5%11%21%19%3
2112
16th to endDay
40%48%21%22%3
1833
October1st to 15thDay
38%313%24%16%2
1650
16th to endDay
39%411%27%15%1
1757
November1st to 15thDay
39%413%21%17%4
1581
16th to endDay
43%310%27%13%1
1497
December1st to 15thDay
45%5%18%20%10%1
1440
16th to endDay
45%5%14%22%10%
1536
January1st to 15thNight
44%5%12%21%13%3
2494
16th to endNight
41%313%26%13%1
2496
February1st to 15thNight
44%313%23%13%1
2287
16th to endNight
41%410%23%17%2
1900
March1st to 15thNight
42%412%24%14%1
2052
16th to endNight
42%411%22%16%2
2058
April1st to 15thNight
41%411%22%17%3
1796
16th to endNight
39%5%9%20%19%5%
1800
May1st to 15thNight
44%6%10%19%16%2
1584
16th to endNight
40%8%14%16%16%3
1497
June1st to 15thNight
37%7%13%23%17%
1440
16th to endNight
35%6%13%26%16%1
1440
July1st to 15thNight
43%8%12%18%13%3
1360
16th to endNight
31%8%18%22%17%1
1492
August1st to 15thNight
34%7%14%23%17%1
1615
16th to endNight
34%6%13%22%20%2
1910
September1st to 15thNight
35%6%11%21%22%3
1768
16th to endNight
39%5%7%20%24%3
1793
October1st to 15thNight
41%49%25%16%2
1980
16th to endNight
34%411%28%19%1
2113
November1st to 15thNight
39%310%23%16%6%
2277
16th to endNight
42%411%25%14%1
2462
December1st to 15thNight
47%5%13%21%11%
2520
16th to endNight
44%5%16%22%10%
2688

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
25%24%32%14%11
62
16th to endDay
21%22%32%17%5%
96
February1st to 15thDay
25%21%38%13%1
90
16th to endDay
18%14%41%23%1
231
March1st to 15thDay
16%16%32%26%7%
270
16th to endDay
23%12%32%23%6%2
288
April1st to 15thDay
21%12%27%22%12%2
270
16th to endDay
20%8%25%25%14%5%
270
May1st to 15thDay
26%16%22%16%12%5%
288
16th to endDay
20%419%25%18%10%
331
June1st to 15thDay
18%6%22%24%20%8%
315
16th to endDay
15%422%33%17%5%
315
July1st to 15thDay
13%118%30%27%8%
305
16th to endDay
10%114%33%28%11%
326
August1st to 15thDay
16%214%28%23%14%
313
16th to endDay
11%16%34%26%18%
332
September1st to 15thDay
15%6%22%16%26%14%
299
16th to endDay
20%115%24%20%16%
254
October1st to 15thDay
20%5%17%28%21%5%
255
16th to endDay
14%10%30%32%10%1
271
November1st to 15thDay
15%9%25%28%17%2
235
16th to endDay
18%11%34%23%11%
117
December1st to 15thDay
21%21%31%11%6%6%
60
16th to endDay
29%12%32%20%4
64
January1st to 15thNight
19%13%38%24%4
720
16th to endNight
21%13%39%24%1
768
February1st to 15thNight
19%15%38%25%1
704
16th to endNight
18%18%40%19%2
631
March1st to 15thNight
20%11%37%25%5%
720
16th to endNight
20%8%37%25%7%1
768
April1st to 15thNight
19%11%37%25%5%
718
16th to endNight
18%8%30%31%11%
720
May1st to 15thNight
20%6%27%34%10%
504
16th to endNight
14%321%40%18%1
375
June1st to 15thNight
14%222%39%20%
360
16th to endNight
10%121%50%16%
360
July1st to 15thNight
12%117%45%23%
340
16th to endNight
10%111%44%28%2
456
August1st to 15thNight
11%110%46%27%2
545
16th to endNight
14%111%39%30%3
764
September1st to 15thNight
15%418%34%24%3
707
16th to endNight
15%216%33%28%3
657
October1st to 15thNight
22%5%21%29%18%2
660
16th to endNight
18%8%30%29%11%
704
November1st to 15thNight
15%7%31%32%12%1
700
16th to endNight
18%15%29%26%9%
720
December1st to 15thNight
21%11%33%24%7%
720
16th to endNight
20%12%39%24%2
768
Page generated at 2017-09-13 07:39:07. Version ac04

Copyright 2017 A. Danko


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