Mount Kobau Star Party
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mount Kobau Star Party clear sky chart from 2005-11-05 to

2017-09-12
.

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
33%
14644
14%
46545
7%
14617
40%
14617
20%
30041

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
20%
718
8%
2506
3%
716
26%
716
9%
1919
January16th to endNight
22%
768
8%
2688
5%
768
26%
768
10%
2043
February1st to 15thNight
26%
701
7%
2363
4%
700
31%
700
13%
1721
February16th to endNight
31%
632
14%
1963
8%
632
40%
632
18%
1319
March1st to 15thNight
28%
720
10%
2158
5%
720
34%
720
16%
1530
March16th to endNight
25%
768
12%
2001
3%
768
32%
768
20%
1427
April1st to 15thNight
34%
719
14%
1799
5%
719
38%
719
26%
1232
April16th to endNight
32%
523
17%
1603
9%
523
40%
523
26%
946
May1st to 15thNight
33%
359
18%
1439
14%
359
48%
359
25%
720
May16th to endNight
41%
374
10%
1496
10%
374
49%
374
21%
829
June1st to 15thNight
39%
360
6%
1308
2%
360
42%
360
24%
740
June16th to endNight
37%
360
11%
1136
1%
360
40%
360
32%
608
July1st to 15thNight
51%
340
11%
1273
7%
340
56%
340
41%
543
July16th to endNight
50%
376
21%
1416
19%
354
71%
354
46%
550
August1st to 15thNight
61%
360
25%
1432
27%
358
72%
358
42%
574
August16th to endNight
51%
654
31%
1800
18%
654
60%
654
51%
869
September1st to 15thNight
53%
706
27%
1765
12%
706
60%
706
51%
927
September16th to endNight
47%
656
27%
1779
13%
656
56%
656
39%
994
October1st to 15thNight
35%
660
17%
1980
11%
660
43%
660
26%
1205
October16th to endNight
36%
704
14%
2255
7%
704
46%
704
20%
1492
November1st to 15thNight
26%
700
11%
2379
6%
700
34%
700
14%
1705
November16th to endNight
21%
720
9%
2520
3%
720
28%
720
11%
1868
December1st to 15thNight
18%
899
9%
2699
3%
899
24%
899
11%
2081
December16th to endNight
17%
867
10%
2787
3%
867
24%
867
9%
2199

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
9%9%47%6%46%5%5%7%34%
48117
Night
6%8%47%6%35%5%5%7%38%
46710
Cloud CoverDay
8%8%36%6%35%5%6%7%38%
48117
Night
7%9%47%5%3445%7%39%
46714
TransparencyDay
43%5%15%22%11%2
47785
Night
43%416%22%10%1
46546
SeeingDay
12%25%30%22%7%1
5838
Night
10%20%28%26%12%1
14651

By Month

Percentage Cloud Cover NW (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
5%11%6%10%8%37%5%6%9%25%
1432
16th to endDay
5%13%5%8%6%35%5%6%8%31%
1536
February1st to 15thDay
6%13%5%8%8%5%6%6%6%9%24%
1498
16th to endDay
314%6%9%7%5%6%7%6%8%24%
1511
March1st to 15thDay
7%15%5%8%7%48%6%6%7%22%
1800
16th to endDay
9%17%6%10%8%36%5%5%6%19%
2223
April1st to 15thDay
8%17%5%9%9%46%46%6%22%
2149
16th to endDay
8%11%47%8%46%5%6%7%28%
2354
May1st to 15thDay
10%10%37%6%46%5%6%7%33%
2511
16th to endDay
17%9%38%6%46%45%7%25%
2615
June1st to 15thDay
18%7%36%7%46%5%46%28%
2646
16th to endDay
14%7%36%7%46%5%5%6%31%
2819
July1st to 15thDay
7%425%6%35%445%50%
2607
16th to endDay
6%3144245%46%54%
2657
August1st to 15thDay
5%2245%35%5%6%6%51%
2520
16th to endDay
6%4145%35%45%6%51%
2400
September1st to 15thDay
7%314423346%58%
2114
16th to endDay
10%6%25%5%345%36%45%
1847
October1st to 15thDay
11%7%36%5%45%46%6%39%
1650
16th to endDay
14%9%48%6%35%45%6%31%
1617
November1st to 15thDay
9%13%5%8%6%37%5%7%8%25%
1479
16th to endDay
5%13%48%7%49%7%6%7%26%
1427
December1st to 15thDay
38%6%8%8%46%7%7%7%30%
1260
16th to endDay
6%13%6%10%6%45%5%6%6%27%
1445
January1st to 15thNight
6%11%7%11%8%45%5%5%7%24%
2506
16th to endNight
6%10%5%10%8%36%5%5%8%28%
2688
February1st to 15thNight
6%12%48%7%5%5%5%6%6%30%
2351
16th to endNight
410%5%8%6%36%7%7%7%32%
1963
March1st to 15thNight
6%10%5%8%6%47%6%6%8%28%
2158
16th to endNight
7%10%48%8%46%6%6%6%28%
1997
April1st to 15thNight
6%9%46%7%5%7%5%6%6%33%
1799
16th to endNight
5%8%345%26%5%6%8%41%
1603
May1st to 15thNight
5%7%235%3445%8%48%
1439
16th to endNight
11%5%245%245%7%12%36%
1496
June1st to 15thNight
11%5%25%6%35%5%6%6%41%
1308
16th to endNight
6%5%23325%5%6%7%48%
1136
July1st to 15thNight
411331445%6%62%
1350
16th to endNight
31222336%7%66%
1512
August1st to 15thNight
2312324447%63%
1440
16th to endNight
32123235%48%61%
1800
September1st to 15thNight
4212324446%63%
1765
16th to endNight
7%5%143245%5%8%50%
1779
October1st to 15thNight
9%6%26%6%45%5%45%43%
1980
16th to endNight
11%8%26%6%45%6%7%7%33%
2255
November1st to 15thNight
8%10%37%7%5%6%5%6%7%30%
2379
16th to endNight
5%14%6%10%7%5%8%5%5%6%27%
2520
December1st to 15thNight
5%12%7%9%8%47%6%5%5%28%
2699
16th to endNight
6%14%6%10%8%36%5%5%6%26%
2787

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 15thDay
6%14%8%14%6%345%5%5%24%
1432
16th to endDay
8%17%8%9%43335%7%27%
1536
February1st to 15thDay
8%16%6%8%6%35%5%5%7%26%
1498
16th to endDay
5%11%37%7%46%8%6%9%28%
1511
March1st to 15thDay
8%13%35%6%48%7%6%8%26%
1800
16th to endDay
7%13%5%8%8%47%6%7%9%22%
2223
April1st to 15thDay
8%10%38%7%47%6%7%9%26%
2149
16th to endDay
8%7%36%7%35%6%6%9%34%
2354
May1st to 15thDay
7%6%26%7%45%5%6%8%38%
2511
16th to endDay
12%7%37%7%36%6%6%8%31%
2615
June1st to 15thDay
15%6%26%6%36%46%7%33%
2646
16th to endDay
10%5%36%6%46%5%6%7%37%
2819
July1st to 15thDay
4314435%45%6%54%
2607
16th to endDay
42133245%5%7%58%
2657
August1st to 15thDay
33134245%5%7%56%
2520
16th to endDay
5%2134245%6%7%55%
2400
September1st to 15thDay
42145%23347%62%
2114
16th to endDay
8%4135%25%5%6%7%48%
1847
October1st to 15thDay
10%5%25%5%35%45%7%43%
1650
16th to endDay
15%13%36%43345%6%32%
1617
November1st to 15thDay
10%14%36%5%35%6%6%10%26%
1479
16th to endDay
8%13%7%9%6%36%45%7%27%
1427
December1st to 15thDay
6%14%7%8%6%35%6%5%8%26%
1260
16th to endDay
8%17%8%11%6%35%35%5%24%
1445
January1st to 15thNight
8%17%8%13%7%3345%5%22%
2506
16th to endNight
7%17%8%12%7%24446%23%
2688
February1st to 15thNight
9%15%7%9%42446%6%29%
2351
16th to endNight
5%9%38%6%35%6%7%9%33%
1963
March1st to 15thNight
8%10%5%7%6%36%5%6%8%30%
2158
16th to endNight
6%8%38%7%47%6%6%8%31%
2001
April1st to 15thNight
7%7%36%6%35%6%7%7%38%
1799
16th to endNight
5%6%25%5%25%5%7%9%44%
1603
May1st to 15thNight
5%41443445%8%51%
1439
16th to endNight
11%324347%46%10%42%
1496
June1st to 15thNight
9%5%24435%6%5%8%44%
1308
16th to endNight
5%3244246%6%9%51%
1136
July1st to 15thNight
321221345%7%65%
1350
16th to endNight
21211335%8%69%
1512
August1st to 15thNight
12322335%7%65%
1440
16th to endNight
311232345%7%65%
1800
September1st to 15thNight
322323345%67%
1765
16th to endNight
6%313323447%56%
1779
October1st to 15thNight
10%5%245%345%5%6%46%
1980
16th to endNight
13%7%25%5%35%5%6%8%35%
2255
November1st to 15thNight
11%14%445%26%5%5%8%30%
2379
16th to endNight
9%17%8%8%6%3445%6%25%
2520
December1st to 15thNight
7%15%7%10%7%445%36%26%
2699
16th to endNight
9%19%8%12%6%23336%23%
2787

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
60%7%14%11%4
1432
16th to endDay
56%6%15%15%41
1536
February1st to 15thDay
55%7%19%14%3
1498
16th to endDay
48%8%19%15%7%
1511
March1st to 15thDay
51%8%19%16%4
1800
16th to endDay
54%5%18%16%4
2223
April1st to 15thDay
51%6%16%18%7%
2149
16th to endDay
44%6%16%25%6%
2354
May1st to 15thDay
41%317%24%11%1
2511
16th to endDay
47%417%23%5%
2619
June1st to 15thDay
47%314%22%8%2
2646
16th to endDay
43%313%25%13%1
2819
July1st to 15thDay
28%39%25%22%8%
2455
16th to endDay
23%49%28%27%6%
2490
August1st to 15thDay
24%411%34%20%5%
2503
16th to endDay
25%313%33%20%3
2400
September1st to 15thDay
23%213%29%27%3
2114
16th to endDay
32%5%17%27%15%2
1847
October1st to 15thDay
38%419%26%10%
1650
16th to endDay
51%5%16%20%4
1617
November1st to 15thDay
51%9%16%15%41
1479
16th to endDay
55%6%14%16%5%
1427
December1st to 15thDay
56%7%16%17%2
1260
16th to endDay
62%5%11%14%5%
1445
January1st to 15thNight
62%414%14%3
2506
16th to endNight
62%415%13%3
2688
February1st to 15thNight
54%6%18%15%4
2363
16th to endNight
45%6%20%21%6%
1963
March1st to 15thNight
49%6%20%17%5%
2158
16th to endNight
48%5%19%20%5%
2001
April1st to 15thNight
41%6%18%24%8%1
1799
16th to endNight
34%420%31%8%
1603
May1st to 15thNight
30%218%30%16%1
1440
16th to endNight
36%423%29%5%
1496
June1st to 15thNight
35%415%31%10%2
1308
16th to endNight
27%419%29%17%1
1136
July1st to 15thNight
18%314%30%23%9%
1273
16th to endNight
13%310%32%31%8%
1416
August1st to 15thNight
17%312%35%25%6%
1432
16th to endNight
16%214%36%25%4
1800
September1st to 15thNight
17%214%32%26%6%
1765
16th to endNight
26%416%31%17%4
1779
October1st to 15thNight
37%318%26%12%
1980
16th to endNight
45%5%19%25%3
2255
November1st to 15thNight
51%8%18%15%42
2379
16th to endNight
59%315%14%6%
2520
December1st to 15thNight
59%6%14%16%2
2699
16th to endNight
64%411%13%6%
2787

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
6%8%28%25%23%8%
60
16th to endDay
35%10%21%23%34
64
February1st to 15thDay
15%27%34%18%3
158
16th to endDay
13%23%34%22%5%
227
March1st to 15thDay
20%37%31%10%1
270
16th to endDay
16%39%28%13%1
288
April1st to 15thDay
20%33%24%16%41
269
16th to endDay
12%36%28%15%42
270
May1st to 15thDay
13%30%30%18%6%1
288
16th to endDay
13%22%25%22%11%4
330
June1st to 15thDay
13%24%26%26%8%
441
16th to endDay
9%24%36%22%6%
614
July1st to 15thDay
422%33%30%7%1
389
16th to endDay
423%30%29%9%1
327
August1st to 15thDay
6%16%30%32%11%3
315
16th to endDay
7%20%33%27%7%3
332
September1st to 15thDay
7%17%32%27%10%4
300
16th to endDay
10%29%32%19%7%1
255
October1st to 15thDay
15%30%30%17%4
255
16th to endDay
28%13%27%20%10%
129
November1st to 15thDay
17%13%49%15%4
73
16th to endDay
15%16%16%31%15%5%
60
December1st to 15thDay
25%8%36%23%5%1
60
16th to endDay
12%9%40%31%6%
64
January1st to 15thNight
13%22%29%22%10%1
720
16th to endNight
13%21%27%23%12%1
768
February1st to 15thNight
11%22%25%27%11%1
704
16th to endNight
8%22%29%25%13%1
632
March1st to 15thNight
11%24%29%24%8%
720
16th to endNight
10%22%33%26%7%
768
April1st to 15thNight
9%21%28%28%11%1
719
16th to endNight
6%25%31%27%8%1
523
May1st to 15thNight
6%23%30%25%12%
360
16th to endNight
10%21%20%33%13%
375
June1st to 15thNight
8%24%23%30%12%
360
16th to endNight
6%19%33%30%10%
360
July1st to 15thNight
416%24%36%17%1
340
16th to endNight
120%24%34%17%
376
August1st to 15thNight
113%19%41%21%1
360
16th to endNight
312%28%32%20%1
654
September1st to 15thNight
315%23%29%24%3
706
16th to endNight
8%13%24%32%18%2
656
October1st to 15thNight
13%16%29%24%14%1
660
16th to endNight
16%13%26%30%10%2
704
November1st to 15thNight
16%20%31%24%6%
700
16th to endNight
17%25%27%17%9%2
720
December1st to 15thNight
15%23%34%21%4
899
16th to endNight
16%24%31%22%5%
867
Page generated at 2017-09-13 04:39:26. Version ac04

Copyright 2017 A. Danko


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