Hugo
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hugo clear sky chart from 2005-11-06 to 2024-01-15.

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
50%
24536
27%
74427
17%
24482
59%
24482
39%
40627

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%
950
30%
2647
19%
946
59%
946
47%
1406
January11th to 20thNight
45%
921
31%
2577
18%
921
56%
921
44%
1393
January21st to endNight
45%
841
33%
2623
19%
841
59%
841
41%
1350
February1st to 10thNight
42%
720
26%
2239
13%
720
56%
720
37%
1227
February11th to 20thNight
38%
704
26%
2098
14%
700
49%
700
35%
1203
February21st to endNight
41%
592
36%
1776
17%
592
58%
592
43%
937
March1st to 10thNight
43%
720
27%
2160
14%
720
54%
720
40%
1168
March11th to 20thNight
45%
712
26%
2108
17%
712
52%
712
40%
1163
March21st to endNight
36%
594
27%
1980
12%
594
54%
594
32%
1079
April1st to 10thNight
35%
540
23%
1800
14%
540
48%
540
31%
984
April11th to 20thNight
32%
533
21%
1777
10%
533
48%
533
29%
1021
April21st to endNight
39%
540
20%
1787
17%
540
49%
540
26%
1059
May1st to 10thNight
44%
540
22%
1620
16%
540
53%
540
30%
990
May11th to 20thNight
42%
531
14%
1574
12%
531
47%
531
28%
1006
May21st to endNight
39%
582
17%
1552
9%
582
47%
582
32%
982
June1st to 10thNight
57%
540
20%
1440
12%
540
62%
540
42%
828
June11th to 20thNight
49%
540
23%
1440
11%
540
56%
540
44%
796
June21st to endNight
56%
540
21%
1440
14%
540
60%
540
38%
885
July1st to 10thNight
61%
525
17%
1400
13%
525
64%
525
33%
897
July11th to 20thNight
73%
522
25%
1392
22%
522
74%
522
41%
823
July21st to endNight
67%
591
18%
1488
15%
558
67%
558
30%
975
August1st to 10thNight
66%
537
16%
1659
16%
534
68%
534
26%
1052
August11th to 20thNight
67%
534
24%
1778
26%
534
71%
534
36%
967
August21st to endNight
70%
594
24%
1980
28%
594
74%
594
40%
1032
September1st to 10thNight
65%
540
27%
1800
26%
540
71%
540
35%
974
September11th to 20thNight
65%
540
33%
1892
31%
540
74%
540
44%
894
September21st to endNight
59%
540
33%
1980
30%
540
69%
540
43%
914
October1st to 10thNight
47%
576
30%
2016
22%
576
56%
576
32%
1059
October11th to 20thNight
56%
720
36%
2160
19%
720
68%
720
53%
1025
October21st to endNight
53%
918
33%
2502
16%
918
62%
918
47%
1332
November1st to 10thNight
59%
925
34%
2405
19%
925
65%
925
56%
1241
November11th to 20thNight
53%
950
38%
2470
19%
950
62%
950
55%
1271
November21st to endNight
51%
950
33%
2470
18%
950
59%
950
48%
1355
December1st to 10thNight
47%
950
29%
2603
15%
950
56%
950
45%
1414
December11th to 20thNight
47%
948
31%
3091
18%
948
57%
948
38%
1608
December21st to endNight
41%
1036
20%
4703
15%
1026
53%
1026
27%
2317

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
5%42442446%8%57%
74833
Night
5%5%2443445%8%56%
74961
TransparencyDay
25%5%11%25%24%9%
74537
Night
26%6%11%24%24%9%
74779
SeeingDay
7%8%26%31%21%7%
14423
Night
7%6%30%39%15%2
24549

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
3423413447%65%
1518
11th to 20thDay
35%34424446%60%
1472
21st to endDay
36%34432347%61%
1750
February1st to 10thDay
36%35%423448%58%
1719
11th to 20thDay
25%37%5%345%45%57%
1749
21st to endDay
36%36%5%2445%7%57%
1480
March1st to 10thDay
45%243345%6%8%57%
1800
11th to 20thDay
5%6%3442335%6%59%
1848
21st to endDay
6%6%25%4245%6%8%52%
2376
April1st to 10thDay
6%5%3332345%8%56%
2160
11th to 20thDay
8%6%245%345%6%8%48%
2131
21st to endDay
8%4245%35%5%6%8%50%
2170
May1st to 10thDay
10%6%25%5%345%6%8%47%
2340
11th to 20thDay
8%6%35%5%345%7%10%45%
2318
21st to endDay
8%423425%5%7%10%51%
2724
June1st to 10thDay
6%213435%5%7%11%54%
2520
11th to 20thDay
5%3134235%6%8%59%
2520
21st to endDay
2323425%5%7%9%56%
2520
July1st to 10thDay
44145%46%6%7%9%50%
2520
11th to 20thDay
23134346%8%10%58%
2520
21st to endDay
6%3245%35%7%8%10%47%
2742
August1st to 10thDay
4424436%7%9%11%47%
2267
11th to 20thDay
5%3143245%8%9%56%
2123
21st to endDay
431433447%9%59%
2376
September1st to 10thDay
43135%345%6%7%60%
2160
11th to 20thDay
6%31322345%6%64%
2066
21st to endDay
6%313323336%67%
1980
October1st to 10thDay
8%41332335%6%63%
1940
11th to 20thDay
4413222346%69%
1800
21st to endDay
5%5%24322325%67%
1836
November1st to 10thDay
322332345%7%67%
1673
11th to 20thDay
2424423345%67%
1710
21st to endDay
45%24424246%64%
1710
December1st to 10thDay
37%243335%5%8%58%
1575
11th to 20thDay
35%3442346%8%57%
1926
21st to endDay
36%35%5%2445%8%54%
2794
January1st to 10thNight
25%2432436%7%60%
2647
11th to 20thNight
25%34423446%62%
2577
21st to endNight
25%35%5%3345%6%60%
2623
February1st to 10thNight
36%25%4245%5%8%56%
2239
11th to 20thNight
36%47%5%345%6%8%50%
2098
21st to endNight
45%3442335%7%60%
1776
March1st to 10thNight
46%2442445%7%58%
2160
11th to 20thNight
6%6%33323447%57%
2108
21st to endNight
6%6%344345%5%7%54%
1980
April1st to 10thNight
6%7%34435%45%7%52%
1800
11th to 20thNight
10%7%25%4435%7%8%45%
1777
21st to endNight
10%6%26%425%45%8%47%
1787
May1st to 10thNight
10%6%25%435%5%5%7%48%
1620
11th to 20thNight
10%9%25%4446%5%8%44%
1574
21st to endNight
12%6%2443447%9%46%
1552
June1st to 10thNight
3314445%5%7%12%53%
1440
11th to 20thNight
44244345%7%10%56%
1440
21st to endNight
44247%36%6%6%9%49%
1440
July1st to 10thNight
6%325%7%46%5%7%10%44%
1440
11th to 20thNight
4215%6%45%6%7%9%51%
1440
21st to endNight
5%5%25%7%5%6%6%7%10%42%
1576
August1st to 10thNight
5%5%36%5%46%8%8%11%39%
1667
11th to 20thNight
6%5%24425%5%8%9%50%
1778
21st to endNight
5%423325%6%6%9%55%
1980
September1st to 10thNight
6%5%244336%5%7%55%
1800
11th to 20thNight
5%3133235%6%8%61%
1892
21st to endNight
6%413323437%65%
1980
October1st to 10thNight
9%5%25%42345%6%56%
2016
11th to 20thNight
3413313345%70%
2160
21st to endNight
5%423323346%65%
2502
November1st to 10thNight
2312324346%68%
2405
11th to 20thNight
25%23313346%69%
2470
21st to endNight
45%25%423447%61%
2470
December1st to 10thNight
25%25%5%3445%6%61%
2603
11th to 20thNight
26%3443446%8%57%
3271
21st to endNight
45%26%5%346%6%8%53%
4873

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
21%312%31%26%7%
1519
11th to 20thDay
26%48%29%25%8%
1472
21st to endDay
26%310%28%26%7%
1750
February1st to 10thDay
27%412%27%22%9%
1719
11th to 20thDay
29%48%27%25%8%
1759
21st to endDay
28%5%8%21%25%12%
1480
March1st to 10thDay
24%5%10%26%23%12%
1800
11th to 20thDay
26%410%25%29%6%
1848
21st to endDay
28%6%14%26%21%6%
2376
April1st to 10thDay
26%6%12%25%23%9%
2160
11th to 20thDay
32%5%12%24%18%9%
2134
21st to endDay
31%6%13%24%21%5%
2170
May1st to 10thDay
34%6%13%25%19%4
2340
11th to 20thDay
33%7%18%24%16%2
2322
21st to endDay
27%8%16%26%16%7%
2724
June1st to 10thDay
22%7%18%28%16%8%
2520
11th to 20thDay
21%7%11%22%23%16%
2520
21st to endDay
21%7%11%24%25%12%
2520
July1st to 10thDay
27%8%12%21%24%9%
2451
11th to 20thDay
18%7%14%26%26%9%
2445
21st to endDay
28%9%17%27%17%3
2590
August1st to 10thDay
26%9%18%26%14%6%
2251
11th to 20thDay
23%5%11%26%25%10%
2123
21st to endDay
21%5%9%27%27%11%
2376
September1st to 10thDay
23%5%9%22%26%15%
2160
11th to 20thDay
20%5%9%18%30%19%
2066
21st to endDay
20%36%20%36%14%
1980
October1st to 10thDay
23%410%21%30%11%
1940
11th to 20thDay
17%37%23%34%16%
1800
21st to endDay
23%28%26%26%15%
1836
November1st to 10thDay
17%410%27%27%16%
1673
11th to 20thDay
20%36%28%33%10%
1710
21st to endDay
23%29%19%31%15%
1710
December1st to 10thDay
26%410%26%27%7%
1575
11th to 20thDay
25%310%23%33%6%
1924
21st to endDay
28%6%11%25%23%7%
2794
January1st to 10thNight
23%411%29%27%6%
2647
11th to 20thNight
24%5%9%25%30%8%
2577
21st to endNight
25%48%32%24%7%
2623
February1st to 10thNight
28%5%11%25%22%8%
2239
11th to 20thNight
31%5%11%28%20%6%
2098
21st to endNight
25%38%24%28%12%
1776
March1st to 10thNight
26%5%9%21%26%12%
2160
11th to 20thNight
27%412%22%26%8%
2108
21st to endNight
29%6%13%25%23%5%
1980
April1st to 10thNight
30%5%11%23%22%9%
1800
11th to 20thNight
33%7%12%23%19%6%
1777
21st to endNight
36%5%12%24%19%4
1787
May1st to 10thNight
33%8%12%25%18%3
1620
11th to 20thNight
37%9%18%21%11%4
1575
21st to endNight
34%8%19%21%12%7%
1552
June1st to 10thNight
23%9%23%25%14%5%
1440
11th to 20thNight
22%8%15%23%19%12%
1440
21st to endNight
30%8%11%24%19%8%
1440
July1st to 10thNight
33%9%14%23%17%4
1400
11th to 20thNight
26%8%11%29%19%6%
1392
21st to endNight
35%10%17%21%14%2
1488
August1st to 10thNight
35%11%17%21%10%6%
1659
11th to 20thNight
28%7%13%28%19%5%
1778
21st to endNight
23%8%14%27%20%9%
1980
September1st to 10thNight
29%6%11%18%25%12%
1800
11th to 20thNight
20%6%12%22%27%14%
1892
21st to endNight
21%47%23%33%11%
1980
October1st to 10thNight
28%7%10%18%26%12%
2016
11th to 20thNight
17%48%23%30%17%
2160
21st to endNight
22%410%23%25%16%
2502
November1st to 10thNight
17%410%25%28%16%
2405
11th to 20thNight
18%38%27%32%11%
2470
21st to endNight
24%38%22%29%14%
2470
December1st to 10thNight
24%413%26%24%8%
2603
11th to 20thNight
25%48%23%34%5%
3272
21st to endNight
27%6%11%25%24%6%
4873

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
6%7%30%37%17%4
270
11th to 20thDay
11%8%25%43%12%1
252
21st to endDay
7%11%38%31%12%1
264
February1st to 10thDay
6%10%44%30%9%2
240
11th to 20thDay
5%8%45%28%13%2
240
21st to endDay
414%43%27%11%2
198
March1st to 10thDay
5%11%32%31%16%5%
240
11th to 20thDay
11%11%34%29%12%3
281
21st to endDay
13%18%34%24%10%1
462
April1st to 10thDay
10%17%35%23%14%3
420
11th to 20thDay
13%16%39%21%10%2
412
21st to endDay
13%16%32%25%11%2
430
May1st to 10thDay
13%14%28%29%12%4
603
11th to 20thDay
14%8%26%28%20%4
625
21st to endDay
11%10%28%27%19%6%
679
June1st to 10thDay
7%6%21%29%27%12%
630
11th to 20thDay
5%7%26%31%24%7%
630
21st to endDay
4423%36%23%9%
630
July1st to 10thDay
5%414%32%32%12%
621
11th to 20thDay
4111%33%37%14%
618
21st to endDay
8%210%30%37%15%
684
August1st to 10thDay
5%213%35%31%14%
502
11th to 20thDay
4321%34%28%10%
437
21st to endDay
3218%37%29%11%
495
September1st to 10thDay
5%219%37%26%11%
450
11th to 20thDay
4416%38%26%12%
356
21st to endDay
11%419%24%27%14%
270
October1st to 10thDay
10%424%23%23%16%
270
11th to 20thDay
5%428%34%20%9%
270
21st to endDay
6%12%31%24%20%6%
297
November1st to 10thDay
49%30%31%22%4
270
11th to 20thDay
5%6%33%34%20%3
270
21st to endDay
8%10%30%31%16%5%
270
December1st to 10thDay
7%9%32%36%13%3
270
11th to 20thDay
7%10%31%31%18%3
270
21st to endDay
8%13%33%34%10%1
297
January1st to 10thNight
6%5%34%39%13%2
950
11th to 20thNight
5%8%37%36%12%1
921
21st to endNight
37%37%42%9%1
841
February1st to 10thNight
7%6%41%40%6%1
720
11th to 20thNight
6%6%44%34%9%1
704
21st to endNight
7%6%41%39%7%
592
March1st to 10thNight
7%10%35%37%11%1
720
11th to 20thNight
9%8%35%37%11%1
712
21st to endNight
8%10%40%34%8%
594
April1st to 10thNight
11%11%39%32%7%
540
11th to 20thNight
15%9%39%29%7%
533
21st to endNight
13%14%29%32%11%1
540
May1st to 10thNight
12%9%30%36%11%1
540
11th to 20thNight
15%6%29%35%14%1
531
21st to endNight
14%8%33%33%11%1
584
June1st to 10thNight
5%5%27%42%20%1
540
11th to 20thNight
5%5%35%43%12%
540
21st to endNight
6%326%45%19%
540
July1st to 10thNight
6%218%46%25%2
525
11th to 20thNight
5%210%49%32%2
522
21st to endNight
7%212%41%34%3
591
August1st to 10thNight
7%213%43%32%3
537
11th to 20thNight
6%315%53%22%1
534
21st to endNight
6%214%46%29%3
594
September1st to 10thNight
8%218%48%23%1
540
11th to 20thNight
6%319%45%24%3
540
21st to endNight
7%426%42%19%3
540
October1st to 10thNight
12%8%28%35%15%3
576
11th to 20thNight
46%31%37%19%4
720
21st to endNight
8%8%28%35%18%3
918
November1st to 10thNight
45%28%44%17%2
925
11th to 20thNight
5%6%32%40%14%2
950
21st to endNight
6%8%30%39%15%2
950
December1st to 10thNight
5%6%36%40%11%2
950
11th to 20thNight
7%6%33%39%13%2
950
21st to endNight
7%10%36%37%10%1
1045
Page generated at 2024-01-11 20:33:52. Version ac07

Copyright 2024 Attilla Danko


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