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 2017-04-08.

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
32%
14262
13%
45279
7%
14235
39%
14235
20%
29459

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
33%
691
14%
1729
5%
691
38%
691
26%
1180
April16th to endNight
31%
480
16%
1470
8%
480
40%
480
26%
860
May1st to 15thNight
33%
329
19%
1319
15%
329
49%
329
25%
646
May16th to endNight
40%
342
9%
1368
7%
342
48%
342
20%
764
June1st to 15thNight
36%
330
7%
1199
2%
330
39%
330
22%
688
June16th to endNight
35%
330
9%
1041
1%
330
39%
330
31%
565
July1st to 15thNight
47%
310
12%
1160
7%
310
53%
310
38%
509
July16th to endNight
49%
348
19%
1304
16%
326
70%
326
44%
517
August1st to 15thNight
59%
330
26%
1312
28%
328
70%
328
39%
541
August16th to endNight
48%
599
28%
1649
15%
599
57%
599
48%
812
September1st to 15thNight
51%
660
28%
1650
12%
660
58%
660
49%
874
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%
45982
Night
6%8%47%6%35%5%5%7%37%
45444
Cloud CoverDay
8%8%36%6%35%5%6%7%37%
45982
Night
7%9%47%5%3445%7%38%
45448
TransparencyDay
43%5%15%22%10%1
45650
Night
43%417%22%9%1
45280
SeeingDay
12%26%31%21%6%1
5176
Night
10%21%28%26%11%1
14269

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
7%16%5%8%9%46%5%6%6%22%
2058
16th to endDay
8%10%47%7%46%5%6%7%29%
2158
May1st to 15thDay
9%9%36%6%46%5%6%7%34%
2301
16th to endDay
18%9%38%7%46%45%7%23%
2391
June1st to 15thDay
19%7%36%6%46%5%46%28%
2425
16th to endDay
15%7%36%8%46%5%5%6%29%
2584
July1st to 15thDay
7%425%6%35%445%49%
2390
16th to endDay
7%4145%25%5%5%6%52%
2461
August1st to 15thDay
6%2246%45%5%6%6%49%
2310
16th to endDay
7%425%5%35%5%5%6%49%
2199
September1st to 15thDay
7%314423345%57%
1980
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%6%6%6%34%
1729
16th to endNight
5%8%345%26%6%6%9%42%
1470
May1st to 15thNight
5%6%235%3445%8%49%
1319
16th to endNight
12%5%245%245%7%13%34%
1368
June1st to 15thNight
11%5%26%6%35%5%5%5%41%
1199
16th to endNight
7%424436%6%6%8%47%
1041
July1st to 15thNight
411332445%6%61%
1237
16th to endNight
31222336%7%65%
1400
August1st to 15thNight
2313424447%60%
1320
16th to endNight
32123245%5%9%58%
1649
September1st to 15thNight
5%312324446%62%
1650
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
7%8%49%7%5%7%6%7%9%27%
2058
16th to endDay
8%7%35%7%45%6%6%9%35%
2158
May1st to 15thDay
7%6%25%7%45%5%6%8%39%
2301
16th to endDay
13%7%37%7%36%6%5%8%29%
2391
June1st to 15thDay
16%6%26%6%36%5%6%6%34%
2425
16th to endDay
11%6%36%6%46%5%6%7%35%
2584
July1st to 15thDay
5%424435%45%6%52%
2390
16th to endDay
43234245%5%7%56%
2461
August1st to 15thDay
33145%345%6%7%54%
2310
16th to endDay
5%3134346%6%7%53%
2199
September1st to 15thDay
42145%23337%61%
1980
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%39%
1729
16th to endNight
46%24425%5%7%9%45%
1470
May1st to 15thNight
4415%42445%8%53%
1319
16th to endNight
11%323447%46%10%41%
1368
June1st to 15thNight
9%5%25%435%6%5%7%44%
1199
16th to endNight
5%3244246%6%9%49%
1041
July1st to 15thNight
321221335%8%63%
1237
16th to endNight
21221335%8%67%
1400
August1st to 15thNight
12333346%7%62%
1320
16th to endNight
311232345%7%63%
1649
September1st to 15thNight
4212324345%66%
1650
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
50%6%17%18%7%
2058
16th to endDay
42%6%16%26%6%1
2158
May1st to 15thDay
40%317%25%11%1
2301
16th to endDay
49%418%21%4
2395
June1st to 15thDay
47%314%22%8%3
2425
16th to endDay
44%314%25%11%
2584
July1st to 15thDay
30%410%25%21%7%
2238
16th to endDay
24%410%29%24%7%
2294
August1st to 15thDay
26%411%36%17%3
2293
16th to endDay
26%314%32%19%3
2199
September1st to 15thDay
23%213%29%26%3
1980
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
40%6%18%24%8%1
1729
16th to endNight
33%422%31%7%
1470
May1st to 15thNight
28%218%31%17%1
1320
16th to endNight
36%425%27%5%
1368
June1st to 15thNight
36%415%30%11%2
1199
16th to endNight
28%420%29%16%
1041
July1st to 15thNight
20%315%30%22%8%
1160
16th to endNight
14%311%33%29%6%
1304
August1st to 15thNight
18%313%37%22%4
1312
16th to endNight
18%314%36%24%3
1649
September1st to 15thNight
18%214%33%25%5%
1650
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
17%36%25%15%4
239
16th to endDay
11%40%26%13%5%2
210
May1st to 15thDay
11%32%30%19%5%1
228
16th to endDay
14%25%25%19%10%3
266
June1st to 15thDay
12%26%27%24%7%
370
16th to endDay
9%26%34%22%5%
529
July1st to 15thDay
5%26%31%27%8%1
322
16th to endDay
5%23%30%29%8%1
271
August1st to 15thDay
7%20%30%29%9%1
255
16th to endDay
9%23%36%21%5%2
268
September1st to 15thDay
8%20%32%25%10%2
255
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
8%22%28%28%10%1
691
16th to endNight
6%27%30%26%8%1
480
May1st to 15thNight
6%25%29%24%13%
330
16th to endNight
9%22%21%31%13%
343
June1st to 15thNight
7%26%24%28%12%
330
16th to endNight
6%20%33%30%8%
330
July1st to 15thNight
418%25%33%16%1
310
16th to endNight
222%23%34%17%
348
August1st to 15thNight
214%20%40%20%1
330
16th to endNight
413%30%32%18%
599
September1st to 15thNight
416%25%28%22%3
660
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 2017-04-09 03:54:10. Version ac04

Copyright 2017 A. Danko


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