Mount Albert Lion's Club
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mount Albert Lion's Club clear sky chart from 2005-11-05 to 2017-08-12.

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
29%
14653
13%
46377
8%
14618
36%
14618
17%
32791

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 15thNight
12%
719
9%
2491
2%
716
20%
716
7%
1995
January16th to endNight
17%
768
10%
2496
4%
768
24%
768
9%
1986
February1st to 15thNight
12%
701
9%
2287
2%
701
21%
701
10%
1802
February16th to endNight
16%
631
12%
2024
4%
631
25%
631
11%
1508
March1st to 15thNight
17%
720
13%
1980
4%
720
26%
720
14%
1484
March16th to endNight
25%
768
20%
2112
9%
768
34%
768
22%
1442
April1st to 15thNight
21%
718
15%
1813
5%
718
27%
718
20%
1330
April16th to endNight
31%
564
19%
1644
8%
564
39%
564
25%
1089
May1st to 15thNight
41%
474
16%
1554
11%
474
48%
474
23%
1012
May16th to endNight
40%
374
16%
1497
13%
374
52%
374
25%
829
June1st to 15thNight
38%
360
12%
1440
10%
360
49%
360
19%
870
June16th to endNight
45%
360
12%
1320
14%
360
50%
360
24%
783
July1st to 15thNight
56%
340
16%
1318
19%
340
62%
340
33%
692
July16th to endNight
53%
468
16%
1503
15%
439
58%
439
31%
867
August1st to 15thNight
58%
527
17%
1575
12%
524
62%
524
37%
916
August16th to endNight
54%
572
21%
1622
11%
572
59%
572
35%
980
September1st to 15thNight
45%
660
19%
1651
8%
660
51%
660
31%
1096
September16th to endNight
50%
657
21%
1842
14%
657
54%
657
30%
1171
October1st to 15thNight
33%
660
17%
1980
12%
660
41%
660
21%
1368
October16th to endNight
18%
704
10%
2112
3%
704
26%
704
12%
1642
November1st to 15thNight
26%
700
18%
2388
14%
700
34%
700
17%
1654
November16th to endNight
21%
720
10%
2520
5%
720
27%
720
10%
1941
December1st to 15thNight
11%
720
5%
2520
1%
720
15%
720
6%
2078
December16th to endNight
8%
768
5%
2688
1%
768
14%
768
5%
2256

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
15%9%37%6%35%45%6%31%
47579
Night
15%9%47%6%3445%6%32%
46555
Cloud CoverDay
15%9%37%6%35%45%6%31%
47589
Night
15%9%47%6%3445%6%32%
46560
TransparencyDay
51%6%12%18%9%
47275
Night
50%6%12%19%10%
46377
SeeingDay
18%11%30%23%11%4
5341
Night
19%13%31%24%9%1
14658

By Month

Percentage Cloud Cover NE (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 15thDay
17%13%5%9%7%45%45%5%20%
1444
16th to endDay
13%13%7%12%9%46%5%5%5%17%
1728
February1st to 15thDay
12%15%6%12%7%5%6%445%19%
1575
16th to endDay
16%14%6%8%6%44445%24%
1449
March1st to 15thDay
14%12%48%8%35%5%46%27%
1969
16th to endDay
15%9%46%5%23345%37%
2112
April1st to 15thDay
21%9%47%5%3445%5%29%
2134
16th to endDay
17%8%35%42345%6%39%
2327
May1st to 15thDay
15%8%35%5%35%45%7%34%
2397
16th to endDay
14%5%25%5%345%5%6%39%
2618
June1st to 15thDay
18%6%245%35%5%5%8%34%
2520
16th to endDay
14%6%25%5%35%5%5%9%36%
2633
July1st to 15thDay
9%435%5%46%5%5%9%40%
2553
16th to endDay
10%5%26%6%36%5%6%9%35%
2560
August1st to 15thDay
10%5%27%6%35%5%6%9%37%
2288
16th to endDay
12%6%25%5%25%5%7%7%38%
2216
September1st to 15thDay
17%6%25%5%25%45%8%35%
1977
16th to endDay
14%6%27%5%24446%40%
1788
October1st to 15thDay
20%8%26%6%33445%32%
1650
16th to endDay
27%12%48%5%33445%21%
1760
November1st to 15thDay
15%13%46%6%3445%5%29%
1465
16th to endDay
17%15%5%9%7%35%5%45%19%
1440
December1st to 15thDay
18%15%6%12%8%46%345%14%
1440
16th to endDay
19%14%8%9%7%46%445%14%
1536
January1st to 15thNight
17%16%6%9%7%44445%18%
2491
16th to endNight
13%15%6%11%9%45%5%5%418%
2496
February1st to 15thNight
12%16%7%8%8%5%5%5%35%21%
2285
16th to endNight
13%12%49%7%45%45%5%25%
2024
March1st to 15thNight
16%12%5%7%6%34345%30%
1968
16th to endNight
14%8%46%42434441%
2112
April1st to 15thNight
19%8%46%424446%33%
1813
16th to endNight
14%8%34433346%41%
1644
May1st to 15thNight
16%6%15%5%345%7%6%37%
1554
16th to endNight
12%423424447%49%
1495
June1st to 15thNight
14%335%5%345%5%7%40%
1440
16th to endNight
11%5%25%43446%8%43%
1320
July1st to 15thNight
7%2144245%47%53%
1398
16th to endNight
7%424435%5%5%8%47%
1606
August1st to 15thNight
7%3233245%7%8%49%
1586
16th to endNight
8%4245%23446%50%
1622
September1st to 15thNight
15%5%245%3435%6%44%
1651
16th to endNight
14%5%24424347%45%
1842
October1st to 15thNight
17%6%36%5%3345%5%37%
1980
16th to endNight
23%9%37%6%35%5%5%5%24%
2112
November1st to 15thNight
18%10%35%43445%7%32%
2388
16th to endNight
19%12%5%7%6%3445%5%23%
2520
December1st to 15thNight
18%15%6%10%8%45%44417%
2520
16th to endNight
20%14%7%12%8%3445%5%13%
2688

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 15thDay
17%14%49%7%45%445%20%
1444
16th to endDay
13%14%6%12%8%46%5%45%17%
1728
February1st to 15thDay
12%16%6%11%8%46%445%18%
1575
16th to endDay
15%16%5%8%8%44345%24%
1449
March1st to 15thDay
14%11%47%9%36%445%27%
1980
16th to endDay
15%9%36%5%33345%37%
2111
April1st to 15thDay
21%10%46%5%35%445%29%
2134
16th to endDay
17%9%35%32345%5%38%
2327
May1st to 15thDay
16%8%25%5%3446%7%34%
2397
16th to endDay
14%6%25%5%35%5%5%7%39%
2618
June1st to 15thDay
19%6%25%435%5%5%7%34%
2520
16th to endDay
14%6%25%5%35%5%6%9%35%
2633
July1st to 15thDay
9%425%6%46%5%6%8%39%
2553
16th to endDay
10%5%36%6%46%6%6%8%34%
2560
August1st to 15thDay
10%6%27%6%345%6%9%37%
2288
16th to endDay
12%6%245%35%5%7%8%38%
2216
September1st to 15thDay
17%6%25%5%3435%8%35%
1977
16th to endDay
14%7%27%5%33446%39%
1788
October1st to 15thDay
20%8%36%6%33446%32%
1650
16th to endDay
26%12%48%5%3344421%
1760
November1st to 15thDay
16%12%46%6%245%5%5%30%
1465
16th to endDay
17%16%5%8%7%35%5%45%19%
1440
December1st to 15thDay
17%16%6%12%8%45%345%14%
1440
16th to endDay
19%14%8%9%7%46%446%14%
1536
January1st to 15thNight
17%16%5%9%8%45%345%18%
2491
16th to endNight
13%14%6%11%8%45%5%45%19%
2496
February1st to 15thNight
12%16%7%8%8%5%5%44421%
2278
16th to endNight
13%12%49%8%46%46%5%25%
2024
March1st to 15thNight
16%12%5%7%7%3433430%
1980
16th to endNight
13%9%46%424345%41%
2112
April1st to 15thNight
19%9%46%5%23346%33%
1813
16th to endNight
14%8%35%423347%41%
1644
May1st to 15thNight
16%5%25%425%5%6%7%37%
1554
16th to endNight
12%42342445%6%48%
1495
June1st to 15thNight
14%5%35%5%345%5%7%40%
1440
16th to endNight
12%5%25%43447%7%42%
1320
July1st to 15thNight
7%3244345%46%53%
1398
16th to endNight
7%4245%25%5%6%8%47%
1606
August1st to 15thNight
7%3234245%7%8%49%
1586
16th to endNight
8%4345%3345%6%50%
1622
September1st to 15thNight
15%5%145%33447%43%
1651
16th to endNight
13%6%2442435%6%45%
1842
October1st to 15thNight
18%5%36%6%3345%6%37%
1980
16th to endNight
24%9%37%5%45%5%46%24%
2112
November1st to 15thNight
18%10%45%435%35%7%32%
2388
16th to endNight
19%12%47%6%35%5%5%6%23%
2520
December1st to 15thNight
18%16%5%10%8%35%45%416%
2520
16th to endNight
20%14%7%12%8%44445%14%
2688

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 15thDay
64%5%11%12%5%
1445
16th to endDay
67%6%9%10%5%
1728
February1st to 15thDay
67%5%9%13%3
1577
16th to endDay
61%49%15%7%
1449
March1st to 15thDay
58%5%12%15%7%
1980
16th to endDay
49%49%18%17%1
2112
April1st to 15thDay
55%5%8%18%11%
2134
16th to endDay
46%5%10%21%14%1
2327
May1st to 15thDay
47%6%11%19%14%1
2397
16th to endDay
42%6%12%21%13%1
2622
June1st to 15thDay
46%6%12%20%12%
2520
16th to endDay
43%6%13%21%12%
2633
July1st to 15thDay
38%7%13%24%14%1
2404
16th to endDay
43%8%13%22%10%1
2400
August1st to 15thDay
42%7%14%20%13%1
2275
16th to endDay
40%7%15%27%9%1
2216
September1st to 15thDay
45%7%14%23%8%
1977
16th to endDay
45%5%13%26%8%
1788
October1st to 15thDay
53%410%20%9%1
1650
16th to endDay
64%5%13%11%3
1760
November1st to 15thDay
54%6%13%16%8%
1465
16th to endDay
65%6%12%11%3
1440
December1st to 15thDay
71%5%12%9%1
1440
16th to endDay
70%6%10%10%2
1536
January1st to 15thNight
66%5%10%11%5%
2491
16th to endNight
64%6%10%13%3
2496
February1st to 15thNight
63%5%10%15%4
2287
16th to endNight
57%5%12%16%7%
2024
March1st to 15thNight
56%412%19%7%
1980
16th to endNight
45%49%22%15%1
2112
April1st to 15thNight
51%49%19%14%
1813
16th to endNight
43%411%19%17%2
1644
May1st to 15thNight
43%6%11%20%15%2
1554
16th to endNight
34%6%14%27%15%2
1497
June1st to 15thNight
40%6%11%24%15%1
1440
16th to endNight
37%7%14%23%16%
1320
July1st to 15thNight
28%6%12%29%22%1
1318
16th to endNight
33%6%14%28%15%2
1503
August1st to 15thNight
29%7%20%28%14%1
1575
16th to endNight
32%6%13%31%14%1
1622
September1st to 15thNight
38%5%15%26%13%
1651
16th to endNight
37%5%12%30%13%
1842
October1st to 15thNight
46%6%12%20%12%
1980
16th to endNight
58%7%13%13%6%
2112
November1st to 15thNight
50%5%12%19%10%1
2388
16th to endNight
60%7%13%13%3
2520
December1st to 15thNight
69%6%11%10%2
2520
16th to endNight
71%6%10%9%2
2688

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 15thDay
14%33%30%16%4
62
16th to endDay
31%16%35%15%1
96
February1st to 15thDay
18%26%44%10%
90
16th to endDay
23%25%37%10%2
93
March1st to 15thDay
21%20%35%19%3
270
16th to endDay
23%14%32%20%7%2
288
April1st to 15thDay
25%16%33%15%7%1
270
16th to endDay
17%14%34%21%9%4
270
May1st to 15thDay
21%10%27%22%12%4
288
16th to endDay
17%11%33%22%11%3
331
June1st to 15thDay
21%12%22%31%10%1
315
16th to endDay
16%7%33%27%12%1
428
July1st to 15thDay
10%7%28%30%16%7%
338
16th to endDay
7%6%30%32%14%8%
326
August1st to 15thDay
12%5%23%27%16%14%
297
16th to endDay
15%324%23%20%12%
268
September1st to 15thDay
11%7%24%25%18%12%
255
16th to endDay
14%5%26%27%17%7%
254
October1st to 15thDay
20%9%33%19%11%5%
255
16th to endDay
30%18%27%19%4
272
November1st to 15thDay
16%12%32%27%6%4
91
16th to endDay
26%25%31%15%1
60
December1st to 15thDay
26%21%31%15%5%
60
16th to endDay
23%29%45%1
64
January1st to 15thNight
23%23%34%14%3
720
16th to endNight
20%17%35%21%5%
768
February1st to 15thNight
21%19%39%17%2
704
16th to endNight
19%20%36%19%3
631
March1st to 15thNight
21%21%34%19%3
720
16th to endNight
17%15%36%20%8%1
768
April1st to 15thNight
22%16%35%21%4
718
16th to endNight
17%13%33%26%8%
564
May1st to 15thNight
18%6%27%32%11%2
474
16th to endNight
13%5%35%28%15%1
375
June1st to 15thNight
14%7%32%33%11%
360
16th to endNight
13%430%36%14%
360
July1st to 15thNight
8%424%43%17%1
340
16th to endNight
7%428%38%19%1
468
August1st to 15thNight
7%322%37%26%2
527
16th to endNight
10%226%33%24%2
572
September1st to 15thNight
16%6%25%26%19%4
660
16th to endNight
16%6%21%33%17%3
657
October1st to 15thNight
20%10%30%24%12%1
660
16th to endNight
27%15%32%18%5%
704
November1st to 15thNight
23%14%31%21%8%
700
16th to endNight
23%20%27%21%6%
720
December1st to 15thNight
26%21%35%13%3
720
16th to endNight
26%18%38%13%2
768
Page generated at 2017-08-13 14:16:35. Version ac04

Copyright 2017 A. Danko


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