Lora Bay
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lora Bay clear sky chart from 2005-11-05 to 2018-01-12.

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
30%
15513
11%
48239
7%
15474
34%
15474
12%
36700

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
10%
924
2%
2777
0%
921
11%
921
3%
2536
January16th to endNight
13%
768
3%
2496
2%
768
15%
768
3%
2248
February1st to 15thNight
14%
701
4%
2287
1%
701
17%
701
5%
1985
February16th to endNight
21%
631
7%
1997
3%
631
25%
631
9%
1628
March1st to 15thNight
21%
720
12%
2004
6%
720
26%
720
13%
1561
March16th to endNight
32%
768
18%
2112
9%
768
38%
768
18%
1503
April1st to 15thNight
29%
688
14%
1811
6%
688
33%
688
18%
1330
April16th to endNight
35%
540
19%
1620
9%
540
42%
540
17%
1110
May1st to 15thNight
42%
510
16%
1590
12%
510
47%
510
20%
1044
May16th to endNight
44%
374
15%
1497
13%
374
55%
374
20%
863
June1st to 15thNight
45%
360
12%
1338
12%
360
53%
360
18%
836
June16th to endNight
47%
360
14%
1260
15%
360
53%
360
22%
762
July1st to 15thNight
61%
340
17%
1190
22%
340
64%
340
32%
626
July16th to endNight
52%
505
16%
1524
16%
472
59%
472
27%
912
August1st to 15thNight
56%
539
16%
1609
12%
536
60%
536
29%
966
August16th to endNight
56%
588
19%
1734
12%
588
61%
588
27%
1093
September1st to 15thNight
52%
720
16%
1848
10%
720
53%
720
28%
1264
September16th to endNight
52%
717
19%
1980
14%
717
54%
717
25%
1339
October1st to 15thNight
35%
720
14%
2160
11%
720
40%
720
16%
1580
October16th to endNight
20%
768
8%
2325
4%
768
25%
768
9%
1920
November1st to 15thNight
24%
760
11%
2588
10%
760
27%
760
10%
2000
November16th to endNight
16%
780
6%
2730
4%
780
20%
780
6%
2321
December1st to 15thNight
9%
780
2%
2730
1%
780
10%
780
2%
2479
December16th to endNight
7%
952
2%
3032
0%
952
9%
952
2%
2794

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
14%8%47%6%35%45%6%31%
49094
Night
15%11%48%7%35%445%27%
48410
Cloud CoverDay
14%8%47%6%35%45%7%31%
49104
Night
15%10%48%7%35%446%27%
48414
TransparencyDay
51%7%11%19%9%
48783
Night
58%6%10%15%8%
48239
SeeingDay
17%11%21%26%16%6%
6057
Night
19%20%22%23%11%2
15519

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
14%15%7%15%11%6%7%5%437%
1400
16th to endDay
9%15%8%17%15%6%8%3337%
1728
February1st to 15thDay
11%14%6%14%12%5%7%5%4411%
1575
16th to endDay
14%13%7%10%9%6%6%445%17%
1473
March1st to 15thDay
12%9%5%9%8%35%5%5%5%27%
1945
16th to endDay
12%7%48%6%35%5%45%36%
2112
April1st to 15thDay
16%10%45%5%3445%6%32%
2146
16th to endDay
15%7%35%5%2335%7%40%
2340
May1st to 15thDay
16%6%2442445%7%41%
2361
16th to endDay
12%5%245%25%46%7%44%
2618
June1st to 15thDay
14%5%244345%7%8%39%
2619
16th to endDay
11%5%24435%5%7%9%41%
2700
July1st to 15thDay
9%5%244245%5%8%46%
2700
16th to endDay
9%325%5%245%6%10%44%
2534
August1st to 15thDay
9%5%245%235%7%8%45%
2340
16th to endDay
11%415%6%35%5%6%9%41%
2455
September1st to 15thDay
17%7%25%434446%38%
2110
16th to endDay
15%5%346%24447%40%
1980
October1st to 15thDay
19%7%28%6%34446%31%
1800
16th to endDay
26%13%39%6%35%445%16%
1898
November1st to 15thDay
15%14%48%7%345%5%6%24%
1600
16th to endDay
17%17%7%10%7%46%45%5%12%
1560
December1st to 15thDay
15%17%10%15%9%46%5%446%
1560
16th to endDay
17%16%9%15%10%5%44347%
1540
January1st to 15thNight
15%16%7%14%14%5%6%5%437%
2777
16th to endNight
11%14%7%16%14%5%7%4339%
2496
February1st to 15thNight
12%14%7%13%12%6%7%445%12%
2285
16th to endNight
12%13%6%12%8%5%6%5%4419%
1997
March1st to 15thNight
14%13%5%8%6%345%45%27%
1992
16th to endNight
12%9%5%9%5%25%33438%
2112
April1st to 15thNight
19%8%45%5%24346%33%
1811
16th to endNight
17%7%25%445%347%37%
1620
May1st to 15thNight
15%5%25%5%34438%38%
1590
16th to endNight
12%5%245%245%5%7%44%
1495
June1st to 15thNight
13%5%25%435%5%5%8%40%
1338
16th to endNight
10%5%344345%410%43%
1260
July1st to 15thNight
8%41343335%8%53%
1260
16th to endNight
8%314435%5%6%7%48%
1630
August1st to 15thNight
10%4144345%5%7%47%
1620
16th to endNight
11%5%15%5%2445%7%47%
1734
September1st to 15thNight
16%4243235%6%8%41%
1848
16th to endNight
16%5%25%4235%47%41%
1980
October1st to 15thNight
20%7%26%6%3435%6%33%
2160
16th to endNight
25%14%37%5%35%45%5%18%
2325
November1st to 15thNight
17%14%47%7%35%45%6%22%
2588
16th to endNight
20%17%6%9%6%35%435%16%
2730
December1st to 15thNight
16%20%8%13%9%46%4338%
2730
16th to endNight
19%16%9%14%9%5%5%4336%
3032

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
13%14%8%14%13%6%8%5%438%
1400
16th to endDay
9%14%7%16%16%6%7%4437%
1728
February1st to 15thDay
11%13%7%15%11%5%7%5%45%11%
1575
16th to endDay
14%14%7%11%9%5%6%5%4416%
1473
March1st to 15thDay
12%9%6%10%9%35%5%5%5%26%
1956
16th to endDay
12%8%47%7%34445%35%
2111
April1st to 15thDay
16%9%47%43445%6%32%
2146
16th to endDay
15%8%25%42445%7%39%
2340
May1st to 15thDay
16%6%245%34446%40%
2361
16th to endDay
11%6%25%43445%8%43%
2618
June1st to 15thDay
14%5%24425%5%7%8%38%
2619
16th to endDay
11%424435%5%6%9%40%
2700
July1st to 15thDay
9%425%435%46%8%45%
2700
16th to endDay
9%415%435%5%6%10%43%
2534
August1st to 15thDay
10%5%244335%6%8%44%
2340
16th to endDay
10%425%5%36%45%9%40%
2455
September1st to 15thDay
17%7%25%434347%38%
2110
16th to endDay
15%5%24435%347%40%
1980
October1st to 15thDay
18%7%37%6%3445%6%31%
1800
16th to endDay
25%13%38%6%35%45%417%
1898
November1st to 15thDay
14%14%5%8%6%3445%7%24%
1600
16th to endDay
17%17%7%11%6%47%445%12%
1560
December1st to 15thDay
15%18%9%14%10%36%5%448%
1560
16th to endDay
17%16%9%14%10%6%5%4347%
1540
January1st to 15thNight
15%16%7%13%12%6%6%5%447%
2777
16th to endNight
10%14%7%16%15%5%7%4449%
2496
February1st to 15thNight
11%15%7%13%13%6%7%5%4412%
2278
16th to endNight
12%13%6%13%8%5%6%5%45%19%
1997
March1st to 15thNight
14%13%6%8%6%345%4427%
2004
16th to endNight
12%8%5%9%5%25%43437%
2112
April1st to 15thNight
19%8%36%5%34346%33%
1811
16th to endNight
16%7%35%5%45%436%38%
1620
May1st to 15thNight
15%5%25%5%35%447%38%
1589
16th to endNight
13%5%15%4245%6%6%45%
1495
June1st to 15thNight
12%5%25%5%35%6%5%8%39%
1338
16th to endNight
11%435%3345%5%9%44%
1260
July1st to 15thNight
8%412424348%53%
1260
16th to endNight
8%313435%5%6%8%47%
1630
August1st to 15thNight
10%5%144345%6%7%47%
1620
16th to endNight
10%5%15%5%2445%7%47%
1734
September1st to 15thNight
16%5%133246%5%7%41%
1848
16th to endNight
16%5%244235%48%41%
1980
October1st to 15thNight
19%8%25%5%44446%33%
2160
16th to endNight
26%15%36%5%34445%19%
2325
November1st to 15thNight
17%13%47%7%35%5%5%5%22%
2588
16th to endNight
19%16%7%9%6%345%45%17%
2730
December1st to 15thNight
16%18%8%13%8%47%4349%
2730
16th to endNight
18%16%9%15%8%5%5%4437%
3032

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
80%6%6%4
1401
16th to endDay
81%6%5%41
1728
February1st to 15thDay
72%7%7%10%1
1577
16th to endDay
69%5%9%9%5%
1473
March1st to 15thDay
57%7%11%15%7%
1956
16th to endDay
47%6%11%18%14%2
2112
April1st to 15thDay
51%49%22%10%1
2146
16th to endDay
43%5%10%23%14%2
2340
May1st to 15thDay
43%5%10%22%15%2
2361
16th to endDay
37%7%13%24%15%1
2622
June1st to 15thDay
39%9%11%25%14%
2619
16th to endDay
37%8%15%24%13%
2700
July1st to 15thDay
31%9%14%25%16%2
2541
16th to endDay
34%9%13%28%12%1
2377
August1st to 15thDay
33%9%15%25%14%1
2327
16th to endDay
37%9%15%26%10%1
2455
September1st to 15thDay
45%7%12%24%9%
2110
16th to endDay
42%7%12%28%8%
1980
October1st to 15thDay
52%6%12%18%9%
1800
16th to endDay
67%6%11%8%4
1898
November1st to 15thDay
60%7%12%13%6%
1600
16th to endDay
74%6%10%7%1
1560
December1st to 15thDay
80%6%7%4
1560
16th to endDay
82%5%6%4
1540
January1st to 15thNight
81%5%6%5%
2777
16th to endNight
79%6%7%41
2496
February1st to 15thNight
74%6%8%8%1
2287
16th to endNight
66%6%10%11%5%
1997
March1st to 15thNight
59%5%10%17%6%
2004
16th to endNight
50%48%19%15%1
2112
April1st to 15thNight
53%49%18%13%
1811
16th to endNight
46%5%8%17%18%2
1620
May1st to 15thNight
45%410%19%17%2
1590
16th to endNight
36%6%11%27%15%2
1497
June1st to 15thNight
40%7%10%24%15%
1338
16th to endNight
36%7%13%26%15%
1260
July1st to 15thNight
28%5%13%30%20%2
1190
16th to endNight
34%7%12%29%15%
1524
August1st to 15thNight
33%6%17%26%14%1
1609
16th to endNight
37%7%13%26%13%1
1734
September1st to 15thNight
40%7%13%26%11%
1848
16th to endNight
42%7%12%26%11%
1980
October1st to 15thNight
53%6%9%20%10%
2160
16th to endNight
67%6%11%10%3
2325
November1st to 15thNight
62%5%12%12%5%1
2588
16th to endNight
72%6%10%8%2
2730
December1st to 15thNight
82%47%41
2730
16th to endNight
83%46%4
3032

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
13%14%46%21%4
89
16th to endDay
35%6%29%25%4
96
February1st to 15thDay
24%12%42%21%
90
16th to endDay
17%13%33%35%
81
March1st to 15thDay
14%19%29%26%8%1
246
16th to endDay
21%15%22%27%9%3
288
April1st to 15thDay
18%14%28%25%10%2
270
16th to endDay
20%15%23%22%12%5%
270
May1st to 15thDay
21%12%16%27%14%7%
288
16th to endDay
14%11%18%28%20%6%
331
June1st to 15thDay
14%12%21%26%20%4
414
16th to endDay
13%12%15%31%20%5%
495
July1st to 15thDay
11%9%14%30%24%8%
475
16th to endDay
10%10%15%30%26%7%
337
August1st to 15thDay
10%6%13%30%23%15%
313
16th to endDay
11%6%15%28%26%11%
332
September1st to 15thDay
14%7%16%20%23%16%
315
16th to endDay
17%7%14%23%22%14%
314
October1st to 15thDay
20%11%21%25%15%5%
315
16th to endDay
30%14%27%19%6%
314
November1st to 15thDay
23%10%24%22%17%2
108
16th to endDay
34%6%42%13%3
90
December1st to 15thDay
17%23%33%20%5%
90
16th to endDay
23%22%40%12%
96
January1st to 15thNight
19%28%30%15%5%
926
16th to endNight
15%24%29%22%6%1
768
February1st to 15thNight
18%23%32%19%4
704
16th to endNight
18%20%27%25%7%
631
March1st to 15thNight
20%23%27%20%7%
720
16th to endNight
16%21%23%24%11%2
768
April1st to 15thNight
20%21%23%26%7%1
688
16th to endNight
17%21%20%24%14%1
540
May1st to 15thNight
16%19%13%29%16%4
510
16th to endNight
11%18%18%30%19%1
375
June1st to 15thNight
13%19%15%32%17%1
360
16th to endNight
11%17%12%31%22%3
360
July1st to 15thNight
9%13%11%35%25%4
340
16th to endNight
7%17%17%31%21%3
505
August1st to 15thNight
12%10%11%33%26%5%
539
16th to endNight
12%11%12%28%28%5%
588
September1st to 15thNight
16%10%16%26%19%10%
720
16th to endNight
16%11%13%29%21%7%
717
October1st to 15thNight
24%13%21%24%12%3
720
16th to endNight
34%18%23%18%5%
768
November1st to 15thNight
25%21%23%18%10%1
760
16th to endNight
26%28%23%15%5%
780
December1st to 15thNight
27%29%28%12%2
780
16th to endNight
23%27%30%15%2
952
Page generated at 2018-01-12 22:01:31. Version ac04

Copyright 2018 A. Danko


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