Pte. au Baril
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pte. au Baril clear sky chart from 2005-11-05 to 2018-08-29.

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
31%
16264
12%
50457
8%
16227
36%
16227
16%
36607

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
16%
973
5%
2899
2%
970
19%
970
8%
2427
January16th to endNight
21%
864
9%
2736
5%
864
25%
864
10%
2186
February1st to 15thNight
19%
762
11%
2482
3%
761
28%
761
10%
1916
February16th to endNight
23%
683
10%
2178
5%
683
29%
683
13%
1671
March1st to 15thNight
25%
780
13%
2174
5%
780
31%
780
17%
1594
March16th to endNight
35%
832
20%
2288
11%
832
43%
832
27%
1532
April1st to 15thNight
26%
737
14%
1947
6%
737
31%
737
19%
1447
April16th to endNight
34%
579
17%
1735
10%
579
40%
579
21%
1195
May1st to 15thNight
43%
519
16%
1689
14%
519
48%
519
22%
1102
May16th to endNight
46%
407
14%
1625
13%
406
56%
406
24%
936
June1st to 15thNight
48%
390
12%
1394
14%
390
54%
390
23%
858
June16th to endNight
49%
390
12%
1365
12%
390
54%
390
26%
833
July1st to 15thNight
62%
370
17%
1295
21%
370
66%
370
35%
698
July16th to endNight
54%
505
15%
1575
15%
476
56%
476
28%
951
August1st to 15thNight
55%
575
17%
1715
13%
572
59%
572
30%
1055
August16th to endNight
52%
624
19%
1854
12%
624
56%
624
29%
1165
September1st to 15thNight
47%
720
15%
1839
8%
720
50%
720
33%
1203
September16th to endNight
46%
717
20%
1985
13%
717
50%
717
29%
1291
October1st to 15thNight
30%
720
14%
2160
10%
720
36%
720
16%
1581
October16th to endNight
20%
768
10%
2339
4%
768
28%
768
11%
1831
November1st to 15thNight
25%
760
13%
2614
10%
760
30%
760
12%
1947
November16th to endNight
17%
780
7%
2730
4%
780
21%
780
8%
2212
December1st to 15thNight
13%
780
3%
2730
1%
780
15%
780
5%
2357
December16th to endNight
14%
1029
7%
3109
2%
1029
18%
1029
7%
2619

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
16%9%36%5%3445%7%34%
51799
Night
17%11%46%5%34446%31%
50624
Cloud CoverDay
16%9%36%5%3445%7%34%
51809
Night
18%11%46%5%34446%31%
50628
TransparencyDay
48%6%12%20%10%1
51484
Night
54%5%12%17%9%
50457
SeeingDay
20%9%29%25%11%3
7007
Night
23%10%27%25%11%1
16268

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
20%17%6%10%6%23246%19%
1368
16th to endDay
16%17%7%8%6%44445%20%
1837
February1st to 15thDay
14%15%6%9%6%34446%23%
1710
16th to endDay
15%15%7%9%6%3333427%
1581
March1st to 15thDay
16%9%47%435%5%46%32%
2105
16th to endDay
13%7%26%43445%7%40%
2288
April1st to 15thDay
20%8%445%34446%31%
2342
16th to endDay
18%7%25%413336%42%
2500
May1st to 15thDay
18%6%34424446%38%
2591
16th to endDay
14%4244345%5%9%42%
2842
June1st to 15thDay
14%5%26%5%345%6%8%37%
2894
16th to endDay
14%5%25%6%25%5%5%9%37%
2925
July1st to 15thDay
10%41442445%8%48%
2925
16th to endDay
10%42443446%8%44%
2838
August1st to 15thDay
11%6%144245%5%8%45%
2487
16th to endDay
13%6%25%5%345%6%7%40%
2632
September1st to 15thDay
15%5%25%42446%6%40%
2120
16th to endDay
19%5%24423447%40%
1974
October1st to 15thDay
22%8%36%433346%34%
1800
16th to endDay
30%8%37%6%34335%23%
1884
November1st to 15thDay
24%10%46%5%345%5%6%23%
1573
16th to endDay
25%17%45%6%44345%18%
1560
December1st to 15thDay
20%22%7%9%5%34345%13%
1560
16th to endDay
20%20%6%8%6%33445%16%
1463
January1st to 15thNight
20%16%7%10%6%3434418%
2899
16th to endNight
16%17%7%9%6%34346%20%
2736
February1st to 15thNight
11%17%6%10%6%35%35%5%23%
2480
16th to endNight
16%12%5%9%7%44445%24%
2178
March1st to 15thNight
15%13%5%6%5%34346%31%
2162
16th to endNight
12%7%37%423345%43%
2288
April1st to 15thNight
21%10%36%42435%5%32%
1947
16th to endNight
19%7%26%5%23347%35%
1735
May1st to 15thNight
16%6%25%5%25%5%5%8%35%
1689
16th to endNight
12%5%243245%7%8%41%
1623
June1st to 15thNight
14%6%245%2445%9%39%
1394
16th to endNight
11%5%244345%5%9%42%
1365
July1st to 15thNight
9%42333445%8%50%
1365
16th to endNight
9%5%2433446%8%45%
1677
August1st to 15thNight
11%4145%335%5%8%46%
1726
16th to endNight
12%5%246%2445%6%45%
1854
September1st to 15thNight
14%42343446%8%44%
1839
16th to endNight
14%6%15%423347%43%
1985
October1st to 15thNight
23%8%36%5%3433432%
2160
16th to endNight
30%9%36%433345%25%
2339
November1st to 15thNight
22%11%46%434446%27%
2614
16th to endNight
27%16%46%5%24435%19%
2730
December1st to 15thNight
22%21%6%8%6%3444413%
2730
16th to endNight
23%18%6%8%6%34345%17%
3109

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
20%17%7%10%5%23245%19%
1368
16th to endDay
16%17%7%8%6%34445%20%
1837
February1st to 15thDay
14%15%6%10%6%3435%6%23%
1710
16th to endDay
15%16%6%9%6%2433426%
1581
March1st to 15thDay
16%10%47%6%34446%31%
2116
16th to endDay
13%7%35%4345%5%6%40%
2287
April1st to 15thDay
21%9%35%5%2445%6%31%
2342
16th to endDay
18%8%24413246%41%
2500
May1st to 15thDay
19%6%25%42445%6%37%
2591
16th to endDay
13%415%3345%6%9%42%
2842
June1st to 15thDay
14%5%25%5%245%7%8%36%
2894
16th to endDay
13%5%35%5%35%46%8%37%
2925
July1st to 15thDay
10%42343435%8%48%
2925
16th to endDay
10%424425%5%6%9%44%
2838
August1st to 15thDay
11%5%244345%5%8%44%
2487
16th to endDay
13%5%25%6%3446%8%39%
2632
September1st to 15thDay
15%5%25%42436%7%40%
2120
16th to endDay
18%6%15%423447%40%
1974
October1st to 15thDay
22%8%36%423346%33%
1800
16th to endDay
30%8%36%6%3433423%
1884
November1st to 15thDay
25%10%46%43445%7%23%
1573
16th to endDay
25%17%5%5%5%35%335%18%
1560
December1st to 15thDay
21%23%6%9%424245%13%
1560
16th to endDay
20%20%6%8%6%34335%17%
1463
January1st to 15thNight
20%16%7%10%6%3443418%
2899
16th to endNight
16%16%7%10%6%34335%20%
2736
February1st to 15thNight
12%17%5%11%7%3435%6%22%
2473
16th to endNight
16%12%5%8%7%45%445%24%
2178
March1st to 15thNight
16%13%47%433445%31%
2174
16th to endNight
12%7%47%432346%42%
2288
April1st to 15thNight
21%10%36%424446%31%
1947
16th to endNight
20%7%36%424337%35%
1735
May1st to 15thNight
16%7%25%5%25%6%47%36%
1688
16th to endNight
12%5%2442447%9%42%
1623
June1st to 15thNight
13%6%2443446%8%40%
1394
16th to endNight
11%5%145%345%5%9%42%
1365
July1st to 15thNight
9%42342446%8%50%
1365
16th to endNight
10%42443447%7%45%
1677
August1st to 15thNight
11%4145%2446%8%45%
1726
16th to endNight
12%5%245%2346%7%44%
1854
September1st to 15thNight
15%41442445%8%44%
1839
16th to endNight
14%6%25%424348%43%
1985
October1st to 15thNight
24%8%26%5%3433433%
2160
16th to endNight
29%9%36%423346%24%
2339
November1st to 15thNight
22%12%36%5%33446%27%
2614
16th to endNight
27%16%46%5%23345%19%
2730
December1st to 15thNight
21%21%7%8%5%3334413%
2730
16th to endNight
22%18%7%8%5%3433417%
3109

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
68%5%11%11%3
1369
16th to endDay
66%6%8%12%5%
1837
February1st to 15thDay
62%6%8%17%4
1712
16th to endDay
60%5%10%16%7%
1581
March1st to 15thDay
52%6%13%17%9%
2116
16th to endDay
41%6%11%21%15%3
2288
April1st to 15thDay
52%6%8%19%12%1
2342
16th to endDay
43%49%23%15%3
2500
May1st to 15thDay
46%5%10%23%13%1
2591
16th to endDay
36%7%14%24%14%1
2846
June1st to 15thDay
42%7%11%24%13%
2894
16th to endDay
42%8%12%23%12%1
2925
July1st to 15thDay
31%7%14%29%15%2
2766
16th to endDay
36%8%13%28%12%
2677
August1st to 15thDay
35%8%16%25%12%
2474
16th to endDay
40%8%15%26%8%
2632
September1st to 15thDay
41%7%14%27%8%
2120
16th to endDay
42%7%14%27%7%
1974
October1st to 15thDay
52%5%12%18%10%
1800
16th to endDay
64%5%13%11%5%
1884
November1st to 15thDay
60%6%12%14%5%
1573
16th to endDay
69%5%13%7%2
1560
December1st to 15thDay
74%5%10%8%1
1560
16th to endDay
71%5%12%7%3
1463
January1st to 15thNight
70%410%9%4
2899
16th to endNight
65%5%10%12%5%
2736
February1st to 15thNight
62%5%12%14%5%
2482
16th to endNight
61%412%14%6%
2178
March1st to 15thNight
54%412%18%9%
2174
16th to endNight
43%410%21%17%3
2288
April1st to 15thNight
53%5%7%19%12%1
1947
16th to endNight
49%38%17%17%2
1735
May1st to 15thNight
44%5%11%22%13%2
1689
16th to endNight
37%6%13%24%16%1
1625
June1st to 15thNight
40%5%13%23%14%2
1394
16th to endNight
37%6%14%25%14%1
1365
July1st to 15thNight
29%414%29%18%3
1295
16th to endNight
36%6%14%27%14%
1575
August1st to 15thNight
35%6%17%26%13%
1715
16th to endNight
37%6%16%27%11%1
1854
September1st to 15thNight
37%5%18%26%10%1
1839
16th to endNight
40%5%15%30%8%
1985
October1st to 15thNight
56%410%18%11%
2160
16th to endNight
62%413%14%5%
2339
November1st to 15thNight
57%6%12%16%5%
2614
16th to endNight
68%413%10%1
2730
December1st to 15thNight
74%6%11%6%1
2730
16th to endNight
71%410%8%4
3109

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
26%20%33%17%2
92
16th to endDay
38%11%24%20%4
144
February1st to 15thDay
30%17%40%11%
135
16th to endDay
34%20%30%14%
120
March1st to 15thDay
22%18%29%22%5%
301
16th to endDay
18%12%35%23%7%2
352
April1st to 15thDay
26%11%29%20%10%1
330
16th to endDay
22%12%29%21%10%3
319
May1st to 15thDay
25%5%29%23%12%4
348
16th to endDay
16%10%29%29%11%3
395
June1st to 15thDay
16%8%33%28%10%1
539
16th to endDay
15%6%33%32%10%2
570
July1st to 15thDay
11%430%33%16%3
550
16th to endDay
11%430%33%16%4
449
August1st to 15thDay
14%423%32%14%9%
358
16th to endDay
20%6%20%27%17%7%
384
September1st to 15thDay
16%5%25%22%21%7%
315
16th to endDay
20%7%22%28%17%4
314
October1st to 15thDay
26%6%31%23%9%1
315
16th to endDay
31%17%28%18%21
300
November1st to 15thDay
30%16%33%13%3
101
16th to endDay
32%17%32%17%
90
December1st to 15thDay
32%20%34%10%3
90
16th to endDay
30%23%35%9%1
96
January1st to 15thNight
28%15%30%20%41
975
16th to endNight
24%11%32%23%7%
864
February1st to 15thNight
21%15%32%23%6%
764
16th to endNight
23%11%33%25%5%
683
March1st to 15thNight
21%15%31%25%5%
780
16th to endNight
16%7%33%30%11%
832
April1st to 15thNight
25%9%31%26%7%
737
16th to endNight
23%7%26%24%16%
579
May1st to 15thNight
19%5%23%34%15%2
519
16th to endNight
15%428%34%17%
407
June1st to 15thNight
17%422%37%17%1
390
16th to endNight
14%323%35%21%2
390
July1st to 15thNight
10%217%43%24%2
370
16th to endNight
11%224%32%25%2
505
August1st to 15thNight
14%219%35%22%5%
575
16th to endNight
15%321%29%25%3
624
September1st to 15thNight
17%5%24%27%18%7%
720
16th to endNight
16%6%23%28%20%4
717
October1st to 15thNight
28%8%27%24%11%1
720
16th to endNight
33%14%26%19%4
768
November1st to 15thNight
28%13%26%21%10%
760
16th to endNight
36%15%24%18%5%
780
December1st to 15thNight
33%17%28%15%3
780
16th to endNight
33%13%30%18%3
1029
Page generated at 2018-08-30 05:34:21. Version ac04

Copyright 2018 A. Danko


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