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 2018-02-14.

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%
15385
14%
48696
8%
15350
36%
15350
17%
34394

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
13%
779
9%
2700
2%
776
21%
776
8%
2139
January16th to endNight
17%
832
10%
2704
4%
832
23%
832
9%
2141
February1st to 15thNight
12%
757
9%
2468
2%
757
21%
757
10%
1945
February16th to endNight
16%
631
12%
2024
4%
631
24%
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
35%
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
37%
360
12%
1440
10%
360
48%
360
19%
870
June16th to endNight
46%
360
12%
1320
14%
360
51%
360
24%
783
July1st to 15thNight
55%
340
16%
1318
19%
340
61%
340
33%
692
July16th to endNight
53%
468
16%
1503
15%
439
58%
439
31%
867
August1st to 15thNight
59%
539
17%
1609
12%
536
64%
536
36%
936
August16th to endNight
54%
624
22%
1770
11%
624
60%
624
35%
1060
September1st to 15thNight
47%
720
19%
1801
8%
720
52%
720
33%
1176
September16th to endNight
51%
717
23%
2010
17%
717
55%
717
31%
1265
October1st to 15thNight
35%
720
16%
2160
12%
720
41%
720
21%
1485
October16th to endNight
19%
768
11%
2304
4%
768
28%
768
13%
1768
November1st to 15thNight
26%
760
16%
2593
13%
760
34%
760
16%
1816
November16th to endNight
20%
780
10%
2730
5%
780
27%
780
10%
2099
December1st to 15thNight
10%
780
5%
2730
1%
780
16%
780
6%
2242
December16th to endNight
8%
832
6%
2912
0%
832
14%
832
6%
2416

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%
49363
Night
15%9%47%6%3445%6%32%
48874
Cloud CoverDay
15%9%37%6%35%45%6%31%
49373
Night
15%9%47%6%3445%6%32%
48879
TransparencyDay
51%6%12%18%9%
49059
Night
50%6%12%19%10%
48696
SeeingDay
18%12%30%22%11%5%
5911
Night
19%13%32%24%9%1
15390

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%
1565
16th to endDay
13%13%6%12%8%46%5%5%5%17%
1872
February1st to 15thDay
13%15%6%11%7%5%6%445%18%
1695
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%
2340
16th to endDay
12%6%245%25%5%6%7%38%
2418
September1st to 15thDay
16%6%25%5%2445%8%36%
2157
16th to endDay
13%6%26%5%24446%41%
1950
October1st to 15thDay
21%8%26%7%33445%32%
1800
16th to endDay
26%11%48%5%33445%22%
1920
November1st to 15thDay
15%14%46%7%3445%5%28%
1590
16th to endDay
17%15%5%8%7%35%5%46%19%
1560
December1st to 15thDay
17%16%7%12%8%46%345%14%
1560
16th to endDay
19%14%7%9%7%45%5%45%15%
1664
January1st to 15thNight
17%15%5%9%7%45%45%5%18%
2700
16th to endNight
13%14%6%11%8%45%5%5%5%19%
2704
February1st to 15thNight
12%15%7%9%8%5%5%5%35%20%
2466
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%3233246%7%8%49%
1620
16th to endNight
8%4245%33446%51%
1770
September1st to 15thNight
14%5%2443335%6%45%
1801
16th to endNight
13%5%24424346%46%
2010
October1st to 15thNight
17%5%36%5%3345%6%37%
2160
16th to endNight
22%9%37%6%35%5%5%6%25%
2304
November1st to 15thNight
18%11%35%33445%6%31%
2593
16th to endNight
19%12%5%7%6%3445%6%23%
2730
December1st to 15thNight
17%15%6%10%8%45%445%16%
2730
16th to endNight
19%14%7%12%8%3445%5%14%
2912

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%8%45%445%20%
1565
16th to endDay
13%14%6%12%9%36%5%45%17%
1872
February1st to 15thDay
13%16%6%11%8%46%445%18%
1695
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%
2340
16th to endDay
12%6%245%35%5%7%8%38%
2418
September1st to 15thDay
16%6%25%5%3436%8%37%
2157
16th to endDay
13%6%27%5%33446%41%
1950
October1st to 15thDay
20%9%36%7%33346%31%
1800
16th to endDay
25%12%48%5%3344422%
1920
November1st to 15thDay
16%12%47%7%245%5%5%28%
1590
16th to endDay
17%15%5%8%7%35%5%45%19%
1560
December1st to 15thDay
16%17%6%12%8%46%345%14%
1560
16th to endDay
19%14%7%9%7%46%446%14%
1664
January1st to 15thNight
17%16%5%9%7%45%45%6%18%
2700
16th to endNight
13%14%6%10%8%45%5%5%5%19%
2704
February1st to 15thNight
12%15%7%9%8%5%5%5%4421%
2459
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%3234345%7%8%49%
1620
16th to endNight
7%4345%335%5%6%50%
1770
September1st to 15thNight
14%5%14433347%45%
1801
16th to endNight
12%6%2442435%6%46%
2010
October1st to 15thNight
17%5%36%6%3345%6%37%
2160
16th to endNight
22%9%27%6%45%5%46%25%
2304
November1st to 15thNight
18%10%46%435%35%7%31%
2593
16th to endNight
19%12%47%6%345%5%6%23%
2730
December1st to 15thNight
17%16%5%10%9%45%45%5%16%
2730
16th to endNight
19%14%7%12%8%44445%14%
2912

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%6%
1566
16th to endDay
66%6%9%10%5%
1872
February1st to 15thDay
67%5%8%14%3
1697
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
2327
16th to endDay
40%7%15%26%9%1
2418
September1st to 15thDay
44%7%13%23%10%
2157
16th to endDay
43%6%12%27%9%
1950
October1st to 15thDay
54%410%20%9%1
1800
16th to endDay
62%6%13%12%4
1920
November1st to 15thDay
55%6%13%15%8%
1590
16th to endDay
64%6%12%11%3
1560
December1st to 15thDay
71%5%11%9%1
1560
16th to endDay
69%5%10%10%3
1664
January1st to 15thNight
65%5%10%12%6%
2700
16th to endNight
64%6%11%13%3
2704
February1st to 15thNight
64%5%10%15%4
2468
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%27%14%1
1609
16th to endNight
32%6%13%30%15%1
1770
September1st to 15thNight
37%5%16%25%14%1
1801
16th to endNight
36%5%11%31%13%
2010
October1st to 15thNight
45%6%12%20%13%
2160
16th to endNight
57%8%13%14%6%
2304
November1st to 15thNight
51%5%12%18%10%1
2593
16th to endNight
60%7%13%13%4
2730
December1st to 15thNight
68%6%10%10%3
2730
16th to endNight
70%6%9%9%4
2912

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
18%27%33%16%4
93
16th to endDay
30%16%36%15%1
144
February1st to 15thDay
23%23%43%9%
130
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
13%5%23%26%17%13%
313
16th to endDay
14%424%24%19%12%
332
September1st to 15thDay
10%6%24%24%20%13%
315
16th to endDay
13%5%23%25%19%12%
314
October1st to 15thDay
22%9%30%19%11%6%
315
16th to endDay
27%19%29%18%5%
336
November1st to 15thDay
21%15%29%23%7%3
126
16th to endDay
27%22%34%13%2
90
December1st to 15thDay
21%24%33%16%4
90
16th to endDay
21%27%40%9%1
96
January1st to 15thNight
23%22%35%14%4
780
16th to endNight
20%15%36%21%5%
832
February1st to 15thNight
20%18%40%17%2
760
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%222%38%26%2
539
16th to endNight
9%326%33%24%2
624
September1st to 15thNight
16%6%24%27%20%5%
720
16th to endNight
15%6%21%31%19%5%
717
October1st to 15thNight
20%9%30%25%13%1
720
16th to endNight
26%15%32%20%5%
768
November1st to 15thNight
24%14%30%20%9%
760
16th to endNight
23%20%28%21%6%
780
December1st to 15thNight
26%20%36%13%2
780
16th to endNight
25%18%38%13%2
832
Page generated at 2018-02-15 10:58:38. Version ac04

Copyright 2018 A. Danko


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