Messier 110 Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Messier 110 Observatory 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
42%
24296
26%
74324
16%
24235
52%
24235
34%
42404

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
30%
950
28%
2458
10%
946
43%
946
36%
1474
January11th to 20thNight
29%
915
28%
2379
9%
915
41%
915
33%
1454
January21st to endNight
29%
990
32%
2574
10%
990
43%
990
36%
1511
February1st to 10thNight
25%
900
21%
2340
6%
900
34%
900
29%
1532
February11th to 20thNight
26%
761
23%
2156
8%
757
36%
757
29%
1320
February21st to endNight
26%
568
28%
1752
10%
568
40%
568
25%
1064
March1st to 10thNight
32%
540
26%
1980
16%
540
43%
540
26%
1103
March11th to 20thNight
29%
540
22%
1980
12%
540
43%
540
25%
1134
March21st to endNight
25%
594
21%
2178
12%
594
39%
594
22%
1312
April1st to 10thNight
27%
540
25%
1977
14%
540
45%
540
29%
1041
April11th to 20thNight
27%
533
24%
1775
13%
533
45%
533
28%
1018
April21st to endNight
29%
540
24%
1630
13%
540
45%
540
29%
1005
May1st to 10thNight
33%
540
21%
1620
13%
540
45%
540
27%
999
May11th to 20thNight
43%
531
22%
1594
19%
531
51%
531
30%
959
May21st to endNight
47%
584
20%
1745
16%
582
56%
582
32%
1064
June1st to 10thNight
62%
540
21%
1620
17%
540
68%
540
39%
898
June11th to 20thNight
59%
540
23%
1620
18%
540
65%
540
45%
847
June21st to endNight
65%
540
26%
1620
22%
540
70%
540
52%
789
July1st to 10thNight
71%
525
21%
1575
20%
525
74%
525
41%
867
July11th to 20thNight
78%
522
26%
1566
26%
522
81%
522
51%
781
July21st to endNight
74%
591
28%
1673
32%
558
77%
558
44%
885
August1st to 10thNight
75%
537
26%
1601
29%
534
79%
534
46%
830
August11th to 20thNight
69%
534
29%
1600
31%
534
73%
534
37%
905
August21st to endNight
77%
594
29%
1894
32%
594
78%
594
45%
948
September1st to 10thNight
69%
540
26%
1942
31%
540
71%
540
37%
982
September11th to 20thNight
61%
540
26%
1980
26%
540
67%
540
31%
1106
September21st to endNight
62%
540
33%
1980
31%
540
69%
540
39%
948
October1st to 10thNight
53%
632
32%
2072
24%
632
61%
632
41%
1069
October11th to 20thNight
37%
720
33%
2160
16%
720
50%
720
40%
1160
October21st to endNight
40%
792
30%
2376
16%
792
51%
792
34%
1340
November1st to 10thNight
39%
744
35%
2224
16%
744
55%
744
43%
1150
November11th to 20thNight
36%
950
29%
2470
12%
950
46%
950
40%
1430
November21st to endNight
35%
950
29%
2470
13%
950
44%
950
34%
1510
December1st to 10thNight
34%
950
28%
2470
11%
950
45%
950
34%
1519
December11th to 20thNight
29%
949
27%
2882
9%
948
40%
948
27%
1781
December21st to endNight
28%
1040
18%
4391
10%
1026
42%
1026
19%
2669

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
11%5%25%43445%7%49%
74945
Night
11%5%2442345%7%54%
74826
TransparencyDay
35%6%11%25%19%4
74670
Night
31%5%10%25%23%6%
74621
SeeingDay
13%9%27%28%19%5%
14312
Night
13%10%31%32%13%1
24302

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
11%8%34423346%53%
1707
11th to 20thDay
13%8%36%422335%51%
1643
21st to endDay
11%8%35%323436%52%
1782
February1st to 10thDay
14%9%47%5%23445%43%
1620
11th to 20thDay
14%5%36%43335%7%46%
1705
21st to endDay
16%8%25%5%35%446%44%
1502
March1st to 10thDay
13%7%36%423446%49%
1980
11th to 20thDay
18%8%34334346%44%
1980
21st to endDay
16%8%47%5%34445%39%
2178
April1st to 10thDay
9%5%35%4345%6%7%48%
1980
11th to 20thDay
15%6%245%345%6%7%44%
2134
21st to endDay
19%6%36%5%2345%6%42%
2326
May1st to 10thDay
18%6%35%5%3445%6%41%
2340
11th to 20thDay
13%7%35%5%345%6%7%43%
2302
21st to endDay
14%5%26%7%45%6%6%9%36%
2531
June1st to 10thDay
5%325%6%35%6%7%10%49%
2340
11th to 20thDay
8%425%5%345%5%8%51%
2340
21st to endDay
5%212335%46%7%60%
2340
July1st to 10thDay
8%3235%46%6%8%10%45%
2340
11th to 20thDay
42235%35%6%6%9%56%
2340
21st to endDay
8%3245%36%6%6%10%48%
2546
August1st to 10thDay
6%315%425%5%8%10%50%
2328
11th to 20thDay
8%425%5%346%7%9%48%
2301
21st to endDay
5%3245%345%6%9%54%
2461
September1st to 10thDay
11%4245%34446%53%
2015
11th to 20thDay
11%6%2443446%7%47%
1980
21st to endDay
9%413424346%58%
1980
October1st to 10thDay
10%42333335%7%57%
1868
11th to 20thDay
11%414322345%62%
1800
21st to endDay
16%5%14324245%54%
1980
November1st to 10thDay
10%324423436%60%
1850
11th to 20thDay
11%5%22323336%62%
1710
21st to endDay
15%6%23322345%55%
1710
December1st to 10thDay
13%6%35%433436%51%
1710
11th to 20thDay
14%6%36%5%34445%46%
2161
21st to endDay
15%12%5%7%6%3445%5%33%
3135
January1st to 10thNight
11%5%2442345%6%54%
2458
11th to 20thNight
12%6%24423346%54%
2379
21st to endNight
10%6%24423445%57%
2574
February1st to 10thNight
14%8%35%423446%47%
2340
11th to 20thNight
13%7%35%323346%51%
2156
21st to endNight
14%7%35%43433452%
1752
March1st to 10thNight
11%6%35%43345%6%51%
1980
11th to 20thNight
18%5%23333345%51%
1980
21st to endNight
16%6%25%434447%46%
2178
April1st to 10thNight
11%5%23423447%55%
1977
11th to 20thNight
15%5%2442335%7%50%
1775
21st to endNight
14%6%35%423346%49%
1630
May1st to 10thNight
13%5%25%4345%6%7%46%
1620
11th to 20thNight
13%5%3433345%7%49%
1593
21st to endNight
10%5%25%4345%7%11%44%
1745
June1st to 10thNight
5%42444446%8%55%
1620
11th to 20thNight
5%323415%47%12%55%
1620
21st to endNight
321322445%9%65%
1620
July1st to 10thNight
5%224425%5%7%12%52%
1620
11th to 20thNight
33133245%5%9%62%
1620
21st to endNight
5%3244245%5%9%56%
1772
August1st to 10thNight
32134346%9%10%54%
1611
11th to 20thNight
6%325%5%36%46%9%53%
1600
21st to endNight
33233345%5%9%60%
1894
September1st to 10thNight
9%424323446%59%
1942
11th to 20thNight
11%6%2443445%8%51%
1980
21st to endNight
8%313424446%62%
1980
October1st to 10thNight
8%414423346%61%
2072
11th to 20thNight
12%412323345%61%
2160
21st to endNight
14%5%2432333458%
2376
November1st to 10thNight
9%413313335%64%
2224
11th to 20thNight
10%423323346%60%
2470
21st to endNight
14%5%24324336%55%
2470
December1st to 10thNight
13%5%24433447%52%
2470
11th to 20thNight
12%7%35%434345%50%
3036
21st to endNight
17%8%35%423346%44%
4532

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
36%49%27%22%3
1708
11th to 20thDay
39%29%26%21%2
1643
21st to endDay
36%410%29%19%3
1782
February1st to 10thDay
45%411%22%16%4
1620
11th to 20thDay
40%39%27%17%4
1715
21st to endDay
42%37%22%18%8%
1502
March1st to 10thDay
39%47%22%19%9%
1980
11th to 20thDay
43%5%9%22%17%4
1980
21st to endDay
48%5%10%22%13%2
2178
April1st to 10thDay
34%6%12%24%18%6%
1980
11th to 20thDay
39%6%12%22%15%6%
2134
21st to endDay
44%6%9%23%17%2
2326
May1st to 10thDay
45%5%9%21%18%2
2340
11th to 20thDay
39%8%13%24%15%1
2306
21st to endDay
43%9%14%23%10%1
2531
June1st to 10thDay
30%9%15%28%16%3
2340
11th to 20thDay
32%6%13%28%17%4
2340
21st to endDay
22%7%13%30%23%5%
2340
July1st to 10thDay
31%9%15%27%16%2
2276
11th to 20thDay
23%7%13%30%24%4
2271
21st to endDay
30%7%14%31%18%1
2405
August1st to 10thDay
27%8%15%28%18%4
2314
11th to 20thDay
32%8%13%25%21%2
2301
21st to endDay
26%7%12%28%20%6%
2461
September1st to 10thDay
32%5%10%23%22%8%
2015
11th to 20thDay
34%7%12%20%21%5%
1980
21st to endDay
28%5%8%22%30%7%
1980
October1st to 10thDay
28%5%12%23%26%6%
1868
11th to 20thDay
26%37%24%31%9%
1800
21st to endDay
34%39%26%20%8%
1980
November1st to 10thDay
27%47%28%26%8%
1850
11th to 20thDay
27%39%28%27%7%
1710
21st to endDay
33%39%24%26%5%
1710
December1st to 10thDay
36%5%8%30%20%2
1710
11th to 20thDay
41%36%23%24%3
2159
21st to endDay
52%410%20%12%2
3135
January1st to 10thNight
32%49%27%23%5%
2458
11th to 20thNight
33%49%26%23%4
2379
21st to endNight
31%38%30%22%6%
2574
February1st to 10thNight
40%411%22%19%5%
2340
11th to 20thNight
37%38%27%19%5%
2156
21st to endNight
39%37%19%22%9%
1752
March1st to 10thNight
35%48%18%22%11%
1980
11th to 20thNight
37%412%22%19%6%
1980
21st to endNight
41%410%26%16%3
2178
April1st to 10thNight
31%411%23%23%9%
1977
11th to 20thNight
35%411%24%18%8%
1775
21st to endNight
37%5%9%23%23%3
1630
May1st to 10thNight
37%6%11%21%21%4
1620
11th to 20thNight
35%6%13%25%18%3
1594
21st to endNight
33%8%16%28%14%1
1746
June1st to 10thNight
25%8%15%30%19%3
1620
11th to 20thNight
23%6%15%33%20%4
1620
21st to endNight
17%6%14%30%25%7%
1620
July1st to 10thNight
24%9%15%30%20%3
1575
11th to 20thNight
19%5%13%28%30%5%
1566
21st to endNight
24%5%11%34%23%2
1673
August1st to 10thNight
20%7%15%34%21%4
1601
11th to 20thNight
28%8%10%21%27%6%
1600
21st to endNight
20%7%13%29%22%9%
1894
September1st to 10thNight
28%49%26%23%10%
1942
11th to 20thNight
33%6%10%18%27%6%
1980
21st to endNight
24%49%24%31%7%
1980
October1st to 10thNight
25%5%11%23%27%10%
2072
11th to 20thNight
28%36%21%31%11%
2160
21st to endNight
31%37%23%26%9%
2376
November1st to 10thNight
24%39%25%30%9%
2224
11th to 20thNight
28%37%25%28%8%
2470
21st to endNight
33%47%21%28%7%
2470
December1st to 10thNight
34%410%27%20%5%
2470
11th to 20thNight
37%38%21%26%4
3037
21st to endNight
43%310%22%19%4
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
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
20%15%33%26%6%
270
11th to 20thDay
24%15%42%16%21
248
21st to endDay
16%16%42%20%6%
264
February1st to 10thDay
23%13%41%20%3
240
11th to 20thDay
18%20%41%19%2
240
21st to endDay
27%22%36%12%3
198
March1st to 10thDay
18%21%39%17%5%
240
11th to 20thDay
22%18%37%20%3
240
21st to endDay
19%26%35%16%4
264
April1st to 10thDay
11%20%42%20%7%
240
11th to 20thDay
21%16%36%21%5%
412
21st to endDay
24%17%30%20%8%1
586
May1st to 10thDay
18%12%38%24%7%1
603
11th to 20thDay
17%10%32%26%11%3
625
21st to endDay
17%8%30%22%17%6%
679
June1st to 10thDay
6%421%37%26%6%
630
11th to 20thDay
8%226%39%21%4
630
21st to endDay
5%223%41%25%5%
630
July1st to 10thDay
8%214%31%32%14%
621
11th to 20thDay
3212%37%38%8%
618
21st to endDay
8%18%33%38%13%
684
August1st to 10thDay
6%111%45%32%5%
626
11th to 20thDay
8%216%34%33%8%
615
21st to endDay
6%29%33%39%11%
580
September1st to 10thDay
11%38%27%36%14%
305
11th to 20thDay
7%115%36%31%10%
270
21st to endDay
13%320%32%25%6%
270
October1st to 10thDay
9%6%29%29%21%6%
270
11th to 20thDay
8%13%41%27%11%1
270
21st to endDay
24%12%29%24%9%2
297
November1st to 10thDay
12%10%40%26%9%2
270
11th to 20thDay
14%12%39%21%11%1
270
21st to endDay
21%16%35%22%5%1
270
December1st to 10thDay
14%14%42%20%9%1
270
11th to 20thDay
19%14%37%22%7%1
270
21st to endDay
12%24%40%19%4
297
January1st to 10thNight
14%14%40%27%6%
950
11th to 20thNight
15%16%37%28%5%
915
21st to endNight
12%16%39%28%5%
990
February1st to 10thNight
18%15%39%25%3
900
11th to 20thNight
17%18%37%25%3
761
21st to endNight
18%17%37%26%3
568
March1st to 10thNight
15%13%38%31%4
540
11th to 20thNight
21%12%37%26%4
540
21st to endNight
20%13%39%24%4
594
April1st to 10thNight
14%15%41%25%5%
540
11th to 20thNight
18%12%37%26%6%
533
21st to endNight
17%12%40%24%7%1
540
May1st to 10thNight
15%9%40%29%6%
540
11th to 20thNight
16%7%30%32%14%1
531
21st to endNight
11%430%34%18%2
584
June1st to 10thNight
7%223%42%25%1
540
11th to 20thNight
5%328%45%18%1
540
21st to endNight
4126%50%19%1
540
July1st to 10thNight
5%115%45%32%3
525
11th to 20thNight
3112%48%33%4
522
21st to endNight
6%111%43%38%2
591
August1st to 10thNight
3113%51%30%2
537
11th to 20thNight
5%114%44%34%3
534
21st to endNight
4112%39%40%3
594
September1st to 10thNight
11%113%42%31%1
540
11th to 20thNight
12%218%37%27%4
540
21st to endNight
11%420%38%24%4
540
October1st to 10thNight
9%331%34%22%3
632
11th to 20thNight
14%8%38%30%10%1
720
21st to endNight
17%12%30%30%11%1
792
November1st to 10thNight
11%9%38%28%13%1
744
11th to 20thNight
13%13%35%30%8%
950
21st to endNight
17%14%32%28%9%
950
December1st to 10thNight
15%15%33%30%6%1
950
11th to 20thNight
19%12%36%27%6%
950
21st to endNight
17%16%35%28%4
1045
Page generated at 2024-01-10 18:35:22. Version ac07

Copyright 2024 Attilla Danko


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