Lake Hamilton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Hamilton clear sky chart from 2005-11-06 to 2024-01-31.

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
47%
24174
25%
74785
17%
24116
55%
24116
31%
44222

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%
949
26%
2458
9%
946
42%
946
29%
1577
January11th to 20thNight
27%
950
26%
2470
8%
950
38%
950
27%
1632
January21st to endNight
28%
1043
28%
2711
9%
1043
40%
1043
30%
1720
February1st to 10thNight
27%
900
21%
2340
7%
900
34%
900
24%
1600
February11th to 20thNight
23%
790
19%
2185
7%
786
31%
786
24%
1455
February21st to endNight
23%
502
26%
1686
9%
502
38%
502
19%
1068
March1st to 10thNight
34%
540
23%
1980
15%
540
44%
540
22%
1212
March11th to 20thNight
30%
540
21%
1980
13%
540
41%
540
20%
1255
March21st to endNight
29%
594
20%
2178
11%
594
41%
594
22%
1336
April1st to 10thNight
31%
540
27%
1837
15%
540
48%
540
28%
1041
April11th to 20thNight
36%
533
26%
1775
18%
533
49%
533
28%
1015
April21st to endNight
36%
540
25%
1800
15%
540
51%
540
30%
1040
May1st to 10thNight
46%
540
20%
1785
17%
540
55%
540
29%
1061
May11th to 20thNight
44%
531
20%
1594
16%
531
51%
531
28%
1004
May21st to endNight
55%
584
21%
1746
17%
582
62%
582
30%
1067
June1st to 10thNight
72%
540
21%
1620
19%
540
76%
540
39%
902
June11th to 20thNight
74%
540
25%
1620
27%
540
75%
540
45%
849
June21st to endNight
76%
540
26%
1620
26%
540
79%
540
46%
840
July1st to 10thNight
75%
525
18%
1575
19%
525
77%
525
36%
914
July11th to 20thNight
81%
522
23%
1566
26%
522
82%
522
45%
828
July21st to endNight
84%
591
26%
1673
31%
558
84%
558
42%
911
August1st to 10thNight
78%
537
23%
1601
27%
534
79%
534
44%
840
August11th to 20thNight
76%
534
27%
1733
32%
534
76%
534
36%
955
August21st to endNight
76%
594
23%
1980
27%
594
77%
594
34%
1101
September1st to 10thNight
75%
540
27%
1800
31%
540
76%
540
38%
972
September11th to 20thNight
68%
540
29%
1853
29%
540
71%
540
32%
1051
September21st to endNight
68%
597
32%
2037
29%
597
73%
597
41%
1034
October1st to 10thNight
65%
720
30%
2160
24%
720
69%
720
43%
1133
October11th to 20thNight
51%
720
33%
2160
21%
720
61%
720
39%
1191
October21st to endNight
43%
792
30%
2376
20%
792
51%
792
32%
1422
November1st to 10thNight
51%
740
32%
2220
22%
740
60%
740
37%
1237
November11th to 20thNight
43%
760
30%
2280
18%
760
54%
760
34%
1287
November21st to endNight
37%
829
28%
2441
16%
829
47%
829
29%
1509
December1st to 10thNight
33%
950
24%
2660
11%
950
44%
950
28%
1690
December11th to 20thNight
33%
948
26%
2933
12%
948
41%
948
24%
1870
December21st to endNight
30%
1039
16%
4352
10%
1026
40%
1026
18%
2603

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%6%25%5%345%5%7%44%
74812
Night
13%5%2442445%7%51%
75330
TransparencyDay
39%7%10%21%19%5%
74536
Night
34%5%10%22%22%6%
75126
SeeingDay
16%8%23%27%20%6%
14219
Night
16%8%24%31%19%2
24183

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
19%8%35%423435%45%
1707
11th to 20thDay
18%8%35%434445%43%
1710
21st to endDay
19%7%2441233451%
1872
February1st to 10thDay
22%8%34425%34440%
1620
11th to 20thDay
20%8%35%5%23445%40%
1663
21st to endDay
26%9%35%5%3333436%
1583
March1st to 10thDay
19%8%24424445%44%
1980
11th to 20thDay
19%9%36%5%34345%40%
1980
21st to endDay
18%8%36%43445%6%38%
2178
April1st to 10thDay
16%6%25%5%24447%45%
2121
11th to 20thDay
18%436%5%33346%45%
2134
21st to endDay
15%7%45%6%3445%6%42%
2160
May1st to 10thDay
18%6%35%4345%5%7%41%
2170
11th to 20thDay
13%6%26%6%35%5%6%7%41%
2302
21st to endDay
10%6%36%6%5%6%6%7%8%37%
2531
June1st to 10thDay
8%5%36%5%46%6%7%8%43%
2340
11th to 20thDay
6%426%6%47%6%7%9%45%
2340
21st to endDay
5%425%5%45%7%8%10%45%
2340
July1st to 10thDay
7%437%7%5%7%7%8%11%34%
2340
11th to 20thDay
6%4245%45%7%7%10%44%
2340
21st to endDay
8%425%5%46%7%8%11%40%
2546
August1st to 10thDay
5%4247%47%7%9%11%40%
2328
11th to 20thDay
11%5%245%35%6%7%10%42%
2168
21st to endDay
7%5%25%6%36%7%7%8%43%
2376
September1st to 10thDay
12%6%245%35%448%47%
2160
11th to 20thDay
15%5%235%345%6%7%46%
2103
21st to endDay
10%4235%3445%7%54%
1904
October1st to 10thDay
9%4245%3346%6%55%
1800
11th to 20thDay
16%5%2332334455%
1800
21st to endDay
19%424423345%51%
1980
November1st to 10thDay
12%6%34323336%55%
1858
11th to 20thDay
13%5%24423347%54%
1900
21st to endDay
22%7%34323345%46%
1729
December1st to 10thDay
18%6%345%23435%46%
1520
11th to 20thDay
14%8%36%6%4444443%
2094
21st to endDay
18%8%25%6%445%46%39%
3135
January1st to 10thNight
19%6%23323346%49%
2458
11th to 20thNight
18%7%24423345%47%
2470
21st to endNight
18%6%23422335%51%
2711
February1st to 10thNight
20%7%46%323345%43%
2340
11th to 20thNight
18%8%35%423345%44%
2184
21st to endNight
23%7%24324335%44%
1686
March1st to 10thNight
20%6%2433345%6%44%
1980
11th to 20thNight
19%7%25%5%2334445%
1980
21st to endNight
15%7%35%5%34345%46%
2178
April1st to 10thNight
12%5%2442435%7%51%
1837
11th to 20thNight
13%42442436%6%50%
1775
21st to endNight
12%5%343235%5%8%50%
1800
May1st to 10thNight
14%3245%3445%7%49%
1785
11th to 20thNight
13%6%25%5%3445%7%45%
1593
21st to endNight
8%6%346%45%45%9%46%
1745
June1st to 10thNight
7%414335%46%10%54%
1620
11th to 20thNight
442442345%8%60%
1620
21st to endNight
5%2233235%6%10%59%
1620
July1st to 10thNight
43346%45%5%9%12%46%
1620
11th to 20thNight
42234245%7%14%53%
1620
21st to endNight
41135%35%5%8%13%53%
1772
August1st to 10thNight
4425%4235%5%11%56%
1611
11th to 20thNight
8%315%435%5%6%11%49%
1733
21st to endNight
5%5%24435%5%6%9%51%
1980
September1st to 10thNight
6%42443346%7%56%
1800
11th to 20thNight
9%5%25%5%25%45%7%51%
1853
21st to endNight
8%413323445%61%
2037
October1st to 10thNight
9%313423446%61%
2160
11th to 20thNight
11%5%24413345%59%
2160
21st to endNight
17%6%2442232455%
2376
November1st to 10thNight
11%5%24323445%59%
2220
11th to 20thNight
11%5%24414345%56%
2280
21st to endNight
17%7%25%323335%51%
2441
December1st to 10thNight
18%7%24423445%48%
2660
11th to 20thNight
18%6%345%33345%47%
3093
21st to endNight
17%8%35%5%23346%45%
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
43%37%22%18%7%
1708
11th to 20thDay
44%5%7%21%20%3
1710
21st to endDay
39%3424%25%5%
1872
February1st to 10thDay
49%47%19%17%4
1620
11th to 20thDay
46%5%6%20%18%5%
1672
21st to endDay
53%36%11%18%8%
1583
March1st to 10thDay
43%48%16%19%10%
1980
11th to 20thDay
47%5%7%20%17%4
1980
21st to endDay
46%6%8%22%16%2
2178
April1st to 10thDay
39%5%9%23%19%5%
2121
11th to 20thDay
41%48%21%20%6%
2134
21st to endDay
42%6%10%19%20%3
2160
May1st to 10thDay
44%7%9%20%17%4
2170
11th to 20thDay
41%8%12%22%15%2
2306
21st to endDay
41%10%15%21%12%1
2531
June1st to 10thDay
36%9%15%23%15%2
2340
11th to 20thDay
34%7%13%26%18%2
2340
21st to endDay
29%9%14%27%18%3
2340
July1st to 10thDay
37%12%16%23%11%1
2276
11th to 20thDay
31%10%16%25%16%2
2271
21st to endDay
33%11%17%26%12%1
2405
August1st to 10thDay
32%11%18%27%12%1
2314
11th to 20thDay
35%9%12%25%15%2
2168
21st to endDay
35%10%14%23%13%4
2376
September1st to 10thDay
36%8%11%20%19%7%
2160
11th to 20thDay
36%8%11%17%22%6%
2103
21st to endDay
31%6%9%19%26%9%
1904
October1st to 10thDay
28%6%11%21%25%9%
1800
11th to 20thDay
32%5%5%18%27%12%
1800
21st to endDay
37%47%19%24%10%
1980
November1st to 10thDay
32%48%24%24%8%
1858
11th to 20thDay
31%48%19%27%10%
1900
21st to endDay
44%36%17%26%5%
1729
December1st to 10thDay
42%5%8%20%18%6%
1520
11th to 20thDay
43%5%6%18%23%5%
2092
21st to endDay
45%6%9%17%17%5%
3135
January1st to 10thNight
38%37%19%27%5%
2458
11th to 20thNight
41%47%21%21%6%
2470
21st to endNight
38%36%20%28%6%
2711
February1st to 10thNight
45%38%19%19%6%
2340
11th to 20thNight
45%37%20%20%6%
2185
21st to endNight
44%46%14%22%9%
1686
March1st to 10thNight
41%5%8%13%21%12%
1980
11th to 20thNight
44%5%7%19%19%7%
1980
21st to endNight
41%5%9%21%20%4
2178
April1st to 10thNight
33%5%10%22%19%10%
1837
11th to 20thNight
33%6%9%22%21%9%
1775
21st to endNight
33%6%11%23%23%3
1800
May1st to 10thNight
35%6%11%23%18%6%
1785
11th to 20thNight
38%6%13%24%16%2
1594
21st to endNight
35%7%15%26%16%1
1746
June1st to 10thNight
25%9%15%29%20%2
1620
11th to 20thNight
24%5%13%34%21%4
1620
21st to endNight
20%7%14%29%25%4
1620
July1st to 10thNight
25%11%22%25%15%1
1575
11th to 20thNight
19%10%20%29%19%3
1566
21st to endNight
21%10%17%33%18%1
1673
August1st to 10thNight
22%7%21%33%16%1
1601
11th to 20thNight
27%8%14%29%18%3
1733
21st to endNight
27%9%15%26%19%3
1980
September1st to 10thNight
25%8%12%24%23%8%
1800
11th to 20thNight
32%6%10%22%22%8%
1853
21st to endNight
25%5%10%21%29%11%
2037
October1st to 10thNight
25%412%21%24%13%
2160
11th to 20thNight
29%47%16%31%14%
2160
21st to endNight
36%45%18%26%11%
2376
November1st to 10thNight
29%48%21%28%10%
2220
11th to 20thNight
31%47%19%27%11%
2280
21st to endNight
38%47%18%28%6%
2441
December1st to 10thNight
40%5%8%19%21%8%
2660
11th to 20thNight
41%36%17%25%8%
3094
21st to endNight
40%5%8%22%20%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
27%13%36%19%5%
270
11th to 20thDay
28%18%36%15%21
270
21st to endDay
24%19%38%14%4
294
February1st to 10thDay
30%12%36%17%5%1
240
11th to 20thDay
30%22%36%10%2
240
21st to endDay
39%17%30%12%3
198
March1st to 10thDay
27%15%35%19%41
240
11th to 20thDay
30%23%29%13%4
240
21st to endDay
26%19%39%14%3
264
April1st to 10thDay
21%17%36%15%10%
381
11th to 20thDay
25%13%29%23%8%1
412
21st to endDay
22%10%36%20%10%2
420
May1st to 10thDay
19%10%31%29%9%1
433
11th to 20thDay
16%6%31%30%15%3
625
21st to endDay
11%5%27%32%19%6%
679
June1st to 10thDay
12%316%31%29%9%
630
11th to 20thDay
7%316%38%27%8%
630
21st to endDay
6%318%38%27%8%
630
July1st to 10thDay
5%214%34%33%12%
621
11th to 20thDay
7%29%31%39%12%
618
21st to endDay
7%28%30%40%14%
684
August1st to 10thDay
7%18%38%35%11%
626
11th to 20thDay
16%26%30%35%11%
482
21st to endDay
11%2425%39%19%
495
September1st to 10thDay
11%28%24%39%15%
450
11th to 20thDay
14%19%25%36%14%
393
21st to endDay
13%411%41%23%8%
270
October1st to 10thDay
7%229%34%23%4
270
11th to 20thDay
17%9%34%25%13%1
270
21st to endDay
27%11%29%23%7%2
297
November1st to 10thDay
18%11%31%24%13%3
270
11th to 20thDay
16%12%38%24%9%1
270
21st to endDay
29%12%29%21%8%1
270
December1st to 10thDay
23%15%33%21%7%1
270
11th to 20thDay
28%12%34%18%7%1
270
21st to endDay
28%13%41%15%3
297
January1st to 10thNight
24%12%30%29%4
950
11th to 20thNight
23%14%32%26%4
950
21st to endNight
22%13%35%27%4
1043
February1st to 10thNight
25%14%30%25%6%
900
11th to 20thNight
23%16%36%23%2
790
21st to endNight
28%13%33%22%3
502
March1st to 10thNight
25%9%30%31%5%
540
11th to 20thNight
23%14%32%27%4
540
21st to endNight
18%12%36%28%5%1
594
April1st to 10thNight
16%12%37%26%8%
540
11th to 20thNight
17%11%31%29%11%1
533
21st to endNight
15%8%38%28%10%
540
May1st to 10thNight
16%5%28%40%11%1
540
11th to 20thNight
15%6%27%31%17%2
531
21st to endNight
10%422%35%26%4
584
June1st to 10thNight
7%211%37%38%4
540
11th to 20thNight
4211%43%35%4
540
21st to endNight
5%110%40%36%7%
540
July1st to 10thNight
419%36%42%8%
525
11th to 20thNight
416%31%48%9%
522
21st to endNight
41433%48%10%
591
August1st to 10thNight
6%25%34%45%7%
537
11th to 20thNight
9%1436%44%6%
534
21st to endNight
8%15%32%46%9%
594
September1st to 10thNight
7%27%33%44%7%
540
11th to 20thNight
10%111%33%41%4
540
21st to endNight
11%313%32%36%6%
597
October1st to 10thNight
10%315%35%33%4
720
11th to 20thNight
15%5%24%36%19%1
720
21st to endNight
21%7%25%28%17%2
792
November1st to 10thNight
13%6%26%35%18%1
740
11th to 20thNight
14%10%28%36%13%
760
21st to endNight
21%9%29%29%11%1
829
December1st to 10thNight
23%9%30%31%7%
950
11th to 20thNight
25%8%29%31%7%
950
21st to endNight
24%12%30%28%6%
1045
Page generated at 2024-01-28 04:26:31. Version ac07

Copyright 2024 Attilla Danko


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