Marra's Frustration Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Marra's Frustration Center clear sky chart from 2005-11-06 to 2024-01-11.

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
40%
23998
19%
74290
13%
23945
47%
23945
23%
49430

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
22%
950
13%
2648
6%
946
29%
946
14%
2058
January11th to 20thNight
19%
777
12%
2405
6%
777
26%
777
13%
1850
January21st to endNight
23%
792
15%
2574
9%
792
30%
792
14%
1889
February1st to 10thNight
23%
720
12%
2241
7%
720
28%
720
14%
1679
February11th to 20thNight
22%
701
15%
2099
8%
700
29%
700
17%
1503
February21st to endNight
19%
592
16%
1776
6%
592
28%
592
15%
1295
March1st to 10thNight
27%
720
17%
2152
11%
720
33%
720
21%
1455
March11th to 20thNight
27%
720
18%
1980
8%
720
36%
720
22%
1369
March21st to endNight
30%
792
17%
2178
8%
792
38%
792
20%
1556
April1st to 10thNight
32%
586
19%
1846
13%
586
43%
586
24%
1207
April11th to 20thNight
35%
533
22%
1728
13%
533
47%
533
26%
1081
April21st to endNight
32%
540
19%
1620
8%
540
42%
540
24%
1072
May1st to 10thNight
32%
540
14%
1620
7%
540
38%
540
20%
1145
May11th to 20thNight
44%
531
16%
1592
10%
531
49%
531
24%
1065
May21st to endNight
58%
583
18%
1745
12%
582
62%
582
33%
1041
June1st to 10thNight
61%
540
18%
1605
15%
540
65%
540
35%
946
June11th to 20thNight
61%
540
22%
1440
15%
540
66%
540
39%
873
June21st to endNight
58%
540
21%
1440
13%
540
64%
540
38%
866
July1st to 10thNight
61%
525
18%
1400
15%
525
63%
525
35%
890
July11th to 20thNight
66%
522
21%
1464
16%
522
70%
522
40%
850
July21st to endNight
66%
591
23%
1672
19%
558
69%
558
36%
978
August1st to 10thNight
69%
537
24%
1600
21%
534
70%
534
37%
926
August11th to 20thNight
67%
534
24%
1598
21%
534
70%
534
35%
942
August21st to endNight
70%
594
25%
1962
24%
594
73%
594
40%
1011
September1st to 10thNight
60%
629
24%
1889
19%
629
65%
629
35%
1087
September11th to 20thNight
65%
720
32%
1980
25%
720
69%
720
41%
1129
September21st to endNight
52%
720
28%
1980
21%
720
57%
720
34%
1220
October1st to 10thNight
56%
720
29%
1980
22%
720
62%
720
39%
1153
October11th to 20thNight
40%
720
24%
2128
18%
720
50%
720
27%
1345
October21st to endNight
33%
792
23%
2515
18%
792
43%
792
22%
1656
November1st to 10thNight
42%
740
25%
2406
18%
740
52%
740
28%
1424
November11th to 20thNight
32%
760
24%
2470
14%
760
45%
760
22%
1589
November21st to endNight
33%
760
19%
2470
14%
760
40%
760
18%
1697
December1st to 10thNight
25%
760
14%
2470
7%
760
34%
760
16%
1782
December11th to 20thNight
26%
759
16%
2975
9%
759
33%
759
14%
2092
December21st to endNight
19%
918
8%
4642
6%
907
26%
907
7%
3709

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%8%36%6%35%5%5%7%37%
75090
Night
15%9%46%5%3445%7%38%
74585
TransparencyDay
47%311%23%14%2
74803
Night
47%310%23%15%2
74392
SeeingDay
19%11%27%23%15%6%
14186
Night
20%8%25%30%15%2
24010

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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
17%13%5%8%7%445%46%27%
1517
11th to 20thDay
19%13%7%10%8%3435%425%
1561
21st to endDay
16%15%5%10%6%35%45%6%25%
1782
February1st to 10thDay
20%13%5%8%5%345%45%27%
1718
11th to 20thDay
17%11%5%9%7%44436%29%
1748
21st to endDay
19%12%6%9%6%24445%30%
1480
March1st to 10thDay
17%11%36%6%35%45%5%34%
1807
11th to 20thDay
19%11%47%6%245%5%6%32%
1980
21st to endDay
23%9%47%6%34446%29%
2178
April1st to 10thDay
14%10%37%6%335%5%7%37%
2128
11th to 20thDay
16%8%36%5%345%5%6%39%
2179
21st to endDay
19%7%36%5%35%5%5%7%35%
2340
May1st to 10thDay
20%8%45%6%35%5%5%6%33%
2340
11th to 20thDay
20%7%46%6%3445%7%34%
2301
21st to endDay
8%6%37%7%47%7%7%10%34%
2531
June1st to 10thDay
12%5%36%6%35%6%7%8%40%
2348
11th to 20thDay
10%425%6%35%6%7%9%43%
2520
21st to endDay
9%5%36%6%45%6%7%9%40%
2520
July1st to 10thDay
11%5%36%6%45%6%7%9%37%
2520
11th to 20thDay
7%5%25%6%46%7%7%10%42%
2444
21st to endDay
10%425%6%46%7%7%9%40%
2547
August1st to 10thDay
8%5%25%5%36%7%6%10%43%
2327
11th to 20thDay
9%5%26%6%45%6%6%11%40%
2303
21st to endDay
8%5%25%5%35%6%6%9%46%
2390
September1st to 10thDay
13%5%3443445%7%47%
2052
11th to 20thDay
9%5%25%43447%8%48%
1980
21st to endDay
14%5%25%5%34446%49%
1980
October1st to 10thDay
11%5%25%5%45%45%7%46%
1980
11th to 20thDay
13%7%25%6%3445%7%44%
1832
21st to endDay
22%8%35%5%34346%38%
1837
November1st to 10thDay
9%6%35%434446%53%
1672
11th to 20thDay
15%9%48%6%3445%7%37%
1710
21st to endDay
18%9%47%6%34346%36%
1710
December1st to 10thDay
21%12%6%8%8%345%45%25%
1710
11th to 20thDay
16%14%6%8%6%35%445%29%
2153
21st to endDay
22%19%6%9%7%3445%5%17%
2965
January1st to 10thNight
17%13%6%10%8%45%445%25%
2648
11th to 20thNight
20%14%6%9%6%35%345%25%
2405
21st to endNight
17%14%6%9%6%34445%28%
2574
February1st to 10thNight
23%11%49%5%345%35%27%
2241
11th to 20thNight
17%9%49%6%35%5%5%7%30%
2098
21st to endNight
22%13%47%5%3345%6%29%
1776
March1st to 10thNight
16%9%46%5%345%46%38%
2152
11th to 20thNight
18%8%36%6%3445%7%36%
1980
21st to endNight
20%8%47%4346%46%34%
2178
April1st to 10thNight
15%7%45%5%45%5%5%7%39%
1846
11th to 20thNight
14%8%35%5%335%6%8%40%
1728
21st to endNight
17%7%26%5%345%5%8%37%
1620
May1st to 10thNight
18%8%37%6%35%45%6%34%
1620
11th to 20thNight
16%6%46%5%45%45%7%38%
1592
21st to endNight
8%425%5%36%6%7%12%42%
1744
June1st to 10thNight
8%5%246%34449%50%
1605
11th to 20thNight
9%424335%5%6%11%47%
1440
21st to endNight
6%325%5%36%5%6%11%47%
1440
July1st to 10thNight
10%5%35%5%345%6%9%46%
1440
11th to 20thNight
6%4243346%6%9%50%
1512
21st to endNight
8%5%25%5%445%6%8%48%
1771
August1st to 10thNight
6%425%5%35%5%6%10%48%
1611
11th to 20thNight
8%425%5%35%6%6%10%46%
1598
21st to endNight
6%42443446%9%55%
1962
September1st to 10thNight
13%4245%3345%8%50%
1889
11th to 20thNight
8%425%42445%7%55%
1980
21st to endNight
13%6%245%34436%51%
1980
October1st to 10thNight
9%425%433347%54%
1980
11th to 20thNight
15%7%25%6%35%447%43%
2128
21st to endNight
18%9%35%5%2445%5%40%
2515
November1st to 10thNight
13%7%34424446%48%
2406
11th to 20thNight
17%7%36%5%3435%6%41%
2470
21st to endNight
19%11%46%6%34447%32%
2470
December1st to 10thNight
21%11%5%7%6%3445%6%29%
2470
11th to 20thNight
18%13%6%7%6%3445%6%29%
3042
21st to endNight
21%18%6%10%7%45%445%17%
4674

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
60%39%18%11%
1518
11th to 20thDay
63%311%16%7%
1561
21st to endDay
61%211%20%5%1
1782
February1st to 10thDay
61%29%18%9%1
1718
11th to 20thDay
58%39%21%9%1
1758
21st to endDay
58%28%21%9%2
1480
March1st to 10thDay
52%29%25%11%1
1807
11th to 20thDay
55%311%19%11%2
1980
21st to endDay
57%310%21%8%1
2178
April1st to 10thDay
48%211%23%14%1
2128
11th to 20thDay
47%29%23%15%4
2179
21st to endDay
50%39%24%11%2
2340
May1st to 10thDay
52%412%22%10%1
2340
11th to 20thDay
50%412%19%13%1
2305
21st to endDay
42%7%15%23%12%1
2531
June1st to 10thDay
41%411%26%16%2
2348
11th to 20thDay
37%414%25%18%2
2520
21st to endDay
40%5%14%23%15%4
2520
July1st to 10thDay
43%413%21%18%2
2451
11th to 20thDay
37%5%12%27%18%2
2369
21st to endDay
38%5%14%25%15%3
2405
August1st to 10thDay
35%6%15%28%15%2
2314
11th to 20thDay
39%412%29%16%1
2303
21st to endDay
34%5%13%24%17%6%
2390
September1st to 10thDay
37%310%25%19%6%
2052
11th to 20thDay
34%310%29%22%2
1980
21st to endDay
37%39%26%23%2
1980
October1st to 10thDay
38%49%25%21%3
1980
11th to 20thDay
40%27%27%20%3
1832
21st to endDay
49%210%22%15%2
1837
November1st to 10thDay
35%38%30%21%3
1672
11th to 20thDay
48%28%24%15%3
1710
21st to endDay
51%28%24%13%1
1710
December1st to 10thDay
63%29%19%6%
1710
11th to 20thDay
59%27%21%11%
2150
21st to endDay
71%38%11%7%
2965
January1st to 10thNight
63%37%18%9%
2648
11th to 20thNight
63%29%18%6%1
2405
21st to endNight
60%29%21%8%1
2574
February1st to 10thNight
61%210%20%6%1
2241
11th to 20thNight
55%39%21%11%1
2099
21st to endNight
57%210%18%9%2
1776
March1st to 10thNight
49%38%24%15%2
2152
11th to 20thNight
49%312%22%11%2
1980
21st to endNight
52%310%24%9%2
2178
April1st to 10thNight
45%310%27%13%2
1846
11th to 20thNight
43%310%19%20%6%
1728
21st to endNight
46%311%22%14%4
1620
May1st to 10thNight
52%411%21%10%3
1620
11th to 20thNight
47%414%21%14%2
1593
21st to endNight
34%5%18%24%15%4
1745
June1st to 10thNight
34%410%28%21%3
1605
11th to 20thNight
32%5%15%24%20%4
1440
21st to endNight
31%6%17%23%18%5%
1440
July1st to 10thNight
37%5%13%21%19%5%
1400
11th to 20thNight
29%5%14%28%20%3
1464
21st to endNight
33%411%32%17%2
1672
August1st to 10thNight
32%414%30%17%3
1600
11th to 20thNight
33%5%12%31%18%1
1598
21st to endNight
27%415%28%22%5%
1962
September1st to 10thNight
34%312%26%18%7%
1889
11th to 20thNight
29%49%28%28%3
1980
21st to endNight
37%28%23%27%3
1980
October1st to 10thNight
31%39%29%24%4
1980
11th to 20thNight
42%26%26%22%2
2128
21st to endNight
47%38%23%17%3
2515
November1st to 10thNight
39%210%22%23%4
2406
11th to 20thNight
46%28%23%19%3
2470
21st to endNight
53%210%22%11%1
2470
December1st to 10thNight
57%310%21%9%1
2470
11th to 20thNight
57%18%23%10%1
3044
21st to endNight
72%28%14%5%
4674

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
26%17%36%15%4
270
11th to 20thDay
28%20%35%13%4
240
21st to endDay
29%23%29%15%4
264
February1st to 10thDay
33%23%28%14%2
240
11th to 20thDay
30%26%32%12%
240
21st to endDay
32%15%44%8%1
198
March1st to 10thDay
26%28%32%12%1
247
11th to 20thDay
28%17%32%17%5%
420
21st to endDay
32%14%31%16%6%1
462
April1st to 10thDay
22%15%30%22%10%1
420
11th to 20thDay
24%18%24%21%10%4
412
21st to endDay
24%16%34%15%9%3
420
May1st to 10thDay
28%11%31%17%9%4
423
11th to 20thDay
22%11%30%21%11%5%
447
21st to endDay
14%6%25%28%18%9%
485
June1st to 10thDay
13%6%24%31%19%7%
458
11th to 20thDay
12%7%27%29%19%6%
630
21st to endDay
11%6%29%30%18%7%
630
July1st to 10thDay
12%417%27%24%16%
621
11th to 20thDay
10%5%22%30%21%13%
542
21st to endDay
13%317%30%24%14%
488
August1st to 10thDay
9%5%14%28%27%16%
446
11th to 20thDay
13%419%31%20%14%
439
21st to endDay
10%416%28%28%14%
495
September1st to 10thDay
12%317%27%29%11%
450
11th to 20thDay
11%314%27%31%14%
450
21st to endDay
17%8%21%25%22%8%
450
October1st to 10thDay
12%7%24%30%20%7%
450
11th to 20thDay
17%13%32%25%11%2
450
21st to endDay
26%11%36%21%41
352
November1st to 10thDay
11%17%36%23%10%3
270
11th to 20thDay
24%20%26%21%8%1
270
21st to endDay
26%15%37%16%5%
270
December1st to 10thDay
22%21%34%15%6%1
270
11th to 20thDay
22%19%37%16%6%
270
21st to endDay
33%15%33%14%31
297
January1st to 10thNight
23%16%30%25%6%
950
11th to 20thNight
30%13%30%23%4
777
21st to endNight
25%13%31%27%3
792
February1st to 10thNight
31%10%30%26%3
720
11th to 20thNight
24%16%33%24%3
703
21st to endNight
30%12%32%25%2
592
March1st to 10thNight
22%13%33%26%5%
720
11th to 20thNight
25%11%32%25%7%1
720
21st to endNight
25%11%28%28%7%
792
April1st to 10thNight
19%12%33%26%9%
586
11th to 20thNight
20%8%32%28%11%1
533
21st to endNight
19%7%37%26%10%1
540
May1st to 10thNight
23%9%29%28%11%1
540
11th to 20thNight
19%5%26%32%17%2
531
21st to endNight
10%321%35%27%4
584
June1st to 10thNight
9%418%44%23%2
540
11th to 20thNight
11%318%42%22%4
540
21st to endNight
6%224%39%26%3
540
July1st to 10thNight
13%211%32%33%8%
525
11th to 20thNight
9%315%35%34%4
522
21st to endNight
10%214%40%31%4
591
August1st to 10thNight
9%211%38%37%3
537
11th to 20thNight
9%112%43%29%5%
534
21st to endNight
7%213%34%39%6%
594
September1st to 10thNight
15%214%31%34%4
629
11th to 20thNight
10%314%33%34%6%
720
21st to endNight
16%6%19%31%26%3
720
October1st to 10thNight
12%323%35%23%4
720
11th to 20thNight
19%9%25%30%15%1
720
21st to endNight
24%9%31%25%10%1
792
November1st to 10thNight
18%8%28%28%17%1
740
11th to 20thNight
21%12%28%27%11%1
760
21st to endNight
26%9%26%31%7%1
760
December1st to 10thNight
29%10%30%25%6%
760
11th to 20thNight
24%9%33%28%6%1
760
21st to endNight
32%12%29%23%4
926
Page generated at 2024-01-08 11:14:18. Version ac07

Copyright 2024 Attilla Danko


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