Fleischmann Planetarium and Science Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fleischmann Planetarium and Science Center clear sky chart from 2005-11-06 to 2024-01-13.

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
61%
23301
29%
74615
24%
23265
68%
23265
43%
37547

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 10thNight
49%
756
21%
2646
17%
756
59%
756
30%
1465
January11th to 20thNight
55%
728
23%
2526
18%
728
63%
728
32%
1345
January21st to endNight
56%
792
26%
2574
26%
792
61%
792
33%
1461
February1st to 10thNight
55%
720
26%
2340
24%
720
63%
720
37%
1253
February11th to 20thNight
54%
701
29%
2099
23%
700
64%
700
41%
1098
February21st to endNight
51%
592
28%
1776
22%
592
61%
592
39%
943
March1st to 10thNight
45%
720
21%
2160
15%
720
56%
720
33%
1243
March11th to 20thNight
53%
720
25%
2021
20%
720
60%
720
40%
1125
March21st to endNight
46%
792
22%
2032
10%
792
54%
792
41%
1157
April1st to 10thNight
50%
720
27%
1800
13%
720
56%
720
43%
1049
April11th to 20thNight
50%
711
30%
1779
12%
711
56%
711
44%
987
April21st to endNight
55%
720
26%
1800
12%
720
60%
720
48%
995
May1st to 10thNight
53%
596
29%
1676
17%
596
59%
596
46%
865
May11th to 20thNight
59%
386
30%
1448
28%
386
66%
386
41%
667
May21st to endNight
63%
388
23%
1552
25%
388
68%
388
35%
745
June1st to 10thNight
66%
360
27%
1440
31%
360
74%
360
41%
634
June11th to 20thNight
66%
360
34%
1440
38%
360
77%
360
57%
514
June21st to endNight
76%
360
34%
1440
41%
360
85%
360
60%
508
July1st to 10thNight
80%
350
35%
1400
42%
350
88%
350
66%
470
July11th to 20thNight
77%
348
37%
1392
43%
348
84%
348
64%
471
July21st to endNight
82%
426
40%
1519
45%
403
86%
403
56%
588
August1st to 10thNight
78%
554
34%
1619
25%
551
82%
551
57%
772
August11th to 20thNight
77%
712
37%
1780
21%
712
81%
712
70%
856
August21st to endNight
75%
792
43%
1980
25%
792
77%
792
75%
928
September1st to 10thNight
78%
720
44%
1800
27%
720
83%
720
78%
825
September11th to 20thNight
74%
720
45%
1831
31%
720
80%
720
68%
874
September21st to endNight
72%
720
42%
1980
34%
720
80%
720
65%
908
October1st to 10thNight
68%
720
34%
2121
29%
720
77%
720
55%
1006
October11th to 20thNight
72%
720
39%
2160
38%
720
79%
720
61%
937
October21st to endNight
69%
792
39%
2434
37%
792
77%
792
59%
1075
November1st to 10thNight
61%
740
31%
2405
30%
740
68%
740
43%
1180
November11th to 20thNight
62%
760
31%
2470
26%
760
71%
760
46%
1190
November21st to endNight
58%
760
30%
2536
25%
760
67%
760
40%
1270
December1st to 10thNight
52%
760
23%
2660
19%
760
59%
760
31%
1432
December11th to 20thNight
49%
759
21%
3199
20%
759
56%
759
21%
1975
December21st to endNight
42%
826
14%
4780
16%
817
52%
817
15%
2736

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
232442445%7%63%
74781
Night
232442445%8%62%
74959
TransparencyDay
21%5%9%22%24%19%
74488
Night
22%5%11%25%23%14%
74774
SeeingDay
7%15%27%28%18%6%
13874
Night
47%23%37%24%4
23320

By Month

Percentage Cloud Cover SW (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 10thDay
2425%6%46%6%8%11%45%
1519
11th to 20thDay
15%26%5%45%5%6%9%52%
1474
21st to endDay
36%25%5%46%7%9%12%41%
1782
February1st to 10thDay
3425%436%5%6%11%51%
1620
11th to 20thDay
1335%5%345%6%11%53%
1750
21st to endDay
25%243345%8%11%55%
1480
March1st to 10thDay
35%26%6%46%6%7%10%45%
1800
11th to 20thDay
35%35%6%35%6%6%8%50%
1937
21st to endDay
1425%5%45%5%7%9%55%
2323
April1st to 10thDay
24345%35%5%6%8%55%
2160
11th to 20thDay
23245%345%5%7%60%
2129
21st to endDay
35%3332345%6%64%
2160
May1st to 10thDay
331442435%7%63%
2281
11th to 20thDay
442432445%7%61%
2441
21st to endDay
45%25%5%36%46%6%53%
2723
June1st to 10thDay
332342446%8%61%
2520
11th to 20thDay
2212223335%76%
2520
21st to endDay
221231233476%
2520
July1st to 10thDay
111221334479%
2520
11th to 20thDay
21222233479%
2520
21st to endDay
2212333445%72%
2705
August1st to 10thDay
2312323446%72%
2309
11th to 20thDay
21221334479%
2122
21st to endDay
11111222385%
2376
September1st to 10thDay
11211123484%
2160
11th to 20thDay
221232333475%
2128
21st to endDay
2212212335%76%
1980
October1st to 10thDay
4323323336%69%
1836
11th to 20thDay
122312347%74%
1800
21st to endDay
2313313448%69%
1921
November1st to 10thDay
34233235%6%8%61%
1674
11th to 20thDay
33132246%6%10%60%
1710
21st to endDay
1424435%5%5%9%58%
1639
December1st to 10thDay
25%35%435%5%6%10%52%
1520
11th to 20thDay
5%9%48%6%35%7%8%10%35%
1928
21st to endDay
28%36%6%46%6%8%12%40%
2794
January1st to 10thNight
2426%6%36%6%7%12%45%
2646
11th to 20thNight
1426%5%35%6%8%11%48%
2526
21st to endNight
35%35%5%346%7%10%47%
2574
February1st to 10thNight
24345%345%6%9%55%
2340
11th to 20thNight
14244345%7%11%54%
2098
21st to endNight
24244245%6%9%57%
1776
March1st to 10thNight
26%25%6%35%5%7%10%50%
2160
11th to 20thNight
25%24425%5%7%10%55%
2021
21st to endNight
2424435%45%9%59%
2032
April1st to 10thNight
2324426%6%6%10%56%
1800
11th to 20thNight
23243245%5%8%63%
1779
21st to endNight
4313334347%64%
1800
May1st to 10thNight
5%31332345%6%64%
1676
11th to 20thNight
34133345%49%61%
1448
21st to endNight
442443447%7%58%
1552
June1st to 10thNight
4324224347%65%
1440
11th to 20thNight
1112212345%77%
1440
21st to endNight
221221224478%
1440
July1st to 10thNight
1111212336%80%
1440
11th to 20thNight
11221333480%
1440
21st to endNight
2312222346%75%
1608
August1st to 10thNight
321332345%5%70%
1628
11th to 20thNight
211222233479%
1780
21st to endNight
22121112483%
1980
September1st to 10thNight
11121122485%
1800
11th to 20thNight
2212122335%78%
1831
21st to endNight
2112223235%77%
1980
October1st to 10thNight
421242333471%
2121
11th to 20thNight
2212212245%76%
2160
21st to endNight
2313212346%73%
2434
November1st to 10thNight
231442346%8%62%
2405
11th to 20thNight
131433446%9%63%
2470
21st to endNight
242343446%7%60%
2536
December1st to 10thNight
35%36%4345%5%8%55%
2660
11th to 20thNight
6%7%47%6%35%6%7%13%39%
3276
21st to endNight
37%36%6%46%7%8%10%40%
4862

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 10thDay
32%8%18%30%11%1
1519
11th to 20thDay
30%6%16%27%17%4
1474
21st to endDay
32%10%14%27%16%1
1782
February1st to 10thDay
27%7%15%29%17%5%
1620
11th to 20thDay
27%414%32%18%4
1760
21st to endDay
23%6%17%32%18%4
1480
March1st to 10thDay
32%6%16%28%16%2
1800
11th to 20thDay
31%6%16%23%20%5%
1937
21st to endDay
26%8%20%29%13%4
2323
April1st to 10thDay
28%5%15%27%20%6%
2160
11th to 20thDay
23%7%10%30%23%7%
2132
21st to endDay
22%411%32%26%5%
2160
May1st to 10thDay
20%48%30%30%7%
2281
11th to 20thDay
23%47%27%30%9%
2444
21st to endDay
30%410%25%24%6%
2724
June1st to 10thDay
21%48%22%31%14%
2520
11th to 20thDay
13%3421%33%27%
2520
21st to endDay
13%4111%30%41%
2520
July1st to 10thDay
8%327%25%55%
2451
11th to 20thDay
10%319%24%53%
2445
21st to endDay
15%417%23%49%
2555
August1st to 10thDay
15%4110%23%46%
2293
11th to 20thDay
10%317%27%52%
2122
21st to endDay
8%216%32%52%
2376
September1st to 10thDay
8%119%28%53%
2160
11th to 20thDay
13%3316%34%30%
2128
21st to endDay
13%3319%35%27%
1980
October1st to 10thDay
18%27%20%31%22%
1836
11th to 20thDay
13%27%26%32%19%
1800
21st to endDay
16%38%30%30%13%
1921
November1st to 10thDay
23%5%11%27%26%8%
1674
11th to 20thDay
20%6%17%29%25%4
1710
21st to endDay
24%5%11%29%26%4
1639
December1st to 10thDay
28%6%14%31%17%4
1520
11th to 20thDay
42%10%11%25%11%2
1928
21st to endDay
35%9%19%26%10%1
2794
January1st to 10thNight
31%6%18%30%13%1
2646
11th to 20thNight
29%6%17%30%14%5%
2526
21st to endNight
31%6%15%28%19%1
2574
February1st to 10thNight
26%6%14%30%19%5%
2340
11th to 20thNight
24%5%14%34%21%2
2099
21st to endNight
23%7%15%34%16%4
1776
March1st to 10thNight
29%7%16%28%16%4
2160
11th to 20thNight
25%6%16%26%22%5%
2021
21st to endNight
23%6%22%30%15%3
2032
April1st to 10thNight
23%7%17%30%18%5%
1800
11th to 20thNight
20%6%15%31%20%8%
1779
21st to endNight
20%5%14%34%22%4
1800
May1st to 10thNight
21%49%29%30%7%
1676
11th to 20thNight
22%411%30%25%9%
1448
21st to endNight
26%413%29%23%5%
1552
June1st to 10thNight
21%410%22%29%13%
1440
11th to 20thNight
12%26%21%34%25%
1440
21st to endNight
11%3314%32%37%
1440
July1st to 10thNight
8%318%29%50%
1400
11th to 20thNight
10%2210%26%50%
1392
21st to endNight
13%337%26%47%
1519
August1st to 10thNight
16%4314%24%39%
1619
11th to 20thNight
10%3110%29%46%
1780
21st to endNight
9%218%34%46%
1980
September1st to 10thNight
8%227%32%50%
1800
11th to 20thNight
11%3419%36%27%
1831
21st to endNight
12%2321%34%28%
1980
October1st to 10thNight
18%27%21%29%23%
2121
11th to 20thNight
13%37%24%34%19%
2160
21st to endNight
15%28%29%33%14%
2434
November1st to 10thNight
21%5%11%30%23%10%
2405
11th to 20thNight
19%5%13%32%26%5%
2470
21st to endNight
23%5%11%30%25%6%
2536
December1st to 10thNight
28%8%14%27%20%4
2660
11th to 20thNight
37%9%13%25%14%2
3276
21st to endNight
39%8%16%24%12%2
4862

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 10thDay
11%18%27%29%12%2
180
11th to 20thDay
8%17%26%30%14%5%
182
21st to endDay
7%10%30%32%16%5%
374
February1st to 10thDay
8%18%29%29%15%2
340
11th to 20thDay
7%20%27%33%12%1
415
21st to endDay
8%21%30%30%10%1
346
March1st to 10thDay
10%20%35%22%10%2
420
11th to 20thDay
10%21%33%21%14%2
420
21st to endDay
11%24%29%26%9%
462
April1st to 10thDay
10%23%30%22%12%2
420
11th to 20thDay
12%26%27%21%11%2
412
21st to endDay
13%20%25%25%12%5%
420
May1st to 10thDay
10%20%30%26%11%4
423
11th to 20thDay
15%20%25%20%13%6%
448
21st to endDay
11%15%24%23%19%8%
485
June1st to 10thDay
8%18%26%22%20%6%
450
11th to 20thDay
9%18%30%24%13%6%
450
21st to endDay
413%25%30%22%7%
450
July1st to 10thDay
29%31%32%17%9%
446
11th to 20thDay
29%28%30%24%8%
444
21st to endDay
26%27%32%22%11%
487
August1st to 10thDay
49%25%29%22%11%
447
11th to 20thDay
38%26%29%22%12%
437
21st to endDay
26%29%32%24%6%
495
September1st to 10thDay
38%28%30%25%7%
450
11th to 20thDay
7%13%24%29%23%4
450
21st to endDay
5%12%24%38%18%3
450
October1st to 10thDay
8%12%25%27%22%6%
450
11th to 20thDay
8%11%22%27%26%6%
450
21st to endDay
7%13%21%33%19%6%
436
November1st to 10thDay
11%10%22%27%20%9%
270
11th to 20thDay
411%23%31%23%9%
270
21st to endDay
5%11%25%30%23%6%
237
December1st to 10thDay
9%11%32%22%17%9%
180
11th to 20thDay
6%12%34%24%16%7%
180
21st to endDay
15%15%22%30%16%2
198
January1st to 10thNight
5%10%28%32%19%6%
760
11th to 20thNight
49%24%40%20%4
728
21st to endNight
5%5%26%37%20%6%
792
February1st to 10thNight
48%28%36%20%4
720
11th to 20thNight
39%27%37%18%5%
704
21st to endNight
5%13%27%39%14%3
592
March1st to 10thNight
5%13%32%32%16%3
720
11th to 20thNight
410%28%31%23%3
720
21st to endNight
314%33%31%16%2
792
April1st to 10thNight
5%11%30%35%18%1
720
11th to 20thNight
416%27%31%18%4
711
21st to endNight
6%13%24%34%20%4
720
May1st to 10thNight
8%11%26%34%18%3
596
11th to 20thNight
5%7%24%39%22%2
386
21st to endNight
8%5%19%38%28%3
389
June1st to 10thNight
7%5%19%43%23%3
360
11th to 20thNight
2425%40%28%1
360
21st to endNight
2218%51%26%2
360
July1st to 10thNight
1116%52%28%3
350
11th to 20thNight
1119%53%26%1
348
21st to endNight
319%50%34%4
426
August1st to 10thNight
3112%45%35%4
554
11th to 20thNight
2216%43%32%4
712
21st to endNight
2318%47%28%3
792
September1st to 10thNight
1216%38%37%5%
720
11th to 20thNight
35%16%34%35%7%
720
21st to endNight
25%19%36%29%10%
720
October1st to 10thNight
5%419%38%26%7%
720
11th to 20thNight
46%16%38%30%6%
720
21st to endNight
6%420%30%29%11%
792
November1st to 10thNight
5%8%22%31%28%6%
740
11th to 20thNight
5%6%24%39%21%5%
760
21st to endNight
47%25%33%25%6%
760
December1st to 10thNight
6%7%26%38%17%6%
760
11th to 20thNight
6%9%28%33%18%5%
760
21st to endNight
7%10%31%35%14%1
836
Page generated at 2024-01-09 22:24:59. Version ac07

Copyright 2024 Attilla Danko


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