La Seigneurie du Triton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Seigneurie du Triton clear sky chart from 2005-11-05 to 2017-09-16.

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
23%
14557
8%
46844
5%
14525
27%
14525
11%
36931

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%
720
6%
2506
4%
716
17%
716
5%
2177
January16th to endNight
21%
768
7%
2688
4%
768
26%
768
7%
2222
February1st to 15thNight
19%
704
7%
2383
4%
701
24%
701
8%
1925
February16th to endNight
17%
631
8%
1893
5%
631
21%
631
10%
1562
March1st to 15thNight
20%
720
11%
2160
9%
720
25%
720
12%
1698
March16th to endNight
24%
768
15%
2013
5%
768
31%
768
15%
1543
April1st to 15thNight
20%
718
11%
1796
4%
718
25%
718
14%
1454
April16th to endNight
21%
556
13%
1636
6%
556
27%
556
15%
1185
May1st to 15thNight
27%
402
12%
1482
11%
402
33%
402
13%
1069
May16th to endNight
23%
375
9%
1488
7%
374
32%
374
12%
1062
June1st to 15thNight
28%
360
5%
1260
3%
360
31%
360
11%
961
June16th to endNight
32%
360
5%
1260
5%
360
34%
360
15%
909
July1st to 15thNight
37%
340
5%
1341
6%
340
39%
340
14%
936
July16th to endNight
38%
376
7%
1418
10%
354
39%
354
14%
990
August1st to 15thNight
40%
372
9%
1443
11%
370
44%
370
13%
1036
August16th to endNight
35%
665
11%
1811
6%
665
37%
665
20%
1328
September1st to 15thNight
35%
720
9%
1821
5%
720
37%
720
22%
1341
September16th to endNight
32%
661
13%
1825
8%
661
35%
661
22%
1299
October1st to 15thNight
22%
660
12%
1928
6%
660
28%
660
15%
1475
October16th to endNight
17%
704
7%
2288
5%
704
21%
704
8%
1915
November1st to 15thNight
18%
700
10%
2277
6%
700
24%
700
9%
1832
November16th to endNight
18%
734
7%
2592
5%
734
20%
734
6%
2176
December1st to 15thNight
12%
750
3%
2700
1%
750
14%
750
4%
2364
December16th to endNight
11%
793
6%
2835
3%
793
16%
793
4%
2472

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
22%12%47%6%34445%23%
47920
Night
20%13%5%8%6%34445%23%
47013
TransparencyDay
62%6%10%13%6%
47607
Night
62%6%10%14%5%
46844
SeeingDay
30%13%27%17%7%2
5947
Night
27%12%29%21%7%
14557

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%19%8%10%9%46%5%3411%
1432
16th to endDay
12%14%8%11%9%46%6%5%6%13%
1536
February1st to 15thDay
10%15%6%13%10%6%8%5%4414%
1476
16th to endDay
14%17%6%12%7%36%445%17%
1580
March1st to 15thDay
16%14%6%11%6%2433423%
1790
16th to endDay
15%13%6%8%6%35%44428%
2211
April1st to 15thDay
25%14%5%6%5%2423425%
2152
16th to endDay
23%12%26%5%22346%31%
2323
May1st to 15thDay
24%9%46%5%2435%6%28%
2481
16th to endDay
26%8%36%5%3445%5%26%
2624
June1st to 15thDay
25%8%35%5%24448%27%
2700
16th to endDay
24%7%46%7%45%45%5%22%
2700
July1st to 15thDay
22%8%37%6%345%6%7%22%
2537
16th to endDay
22%8%37%7%45%446%25%
2654
August1st to 15thDay
25%8%38%7%45%5%5%6%19%
2494
16th to endDay
19%8%37%6%45%5%5%7%24%
2390
September1st to 15thDay
25%8%36%423245%32%
2139
16th to endDay
24%8%25%424446%32%
1825
October1st to 15thDay
28%14%47%42333424%
1700
16th to endDay
32%18%46%42333316%
1584
November1st to 15thDay
24%18%5%7%42433420%
1581
16th to endDay
23%20%7%11%41232417%
1365
December1st to 15thDay
22%22%5%9%9%4432312%
1260
16th to endDay
20%20%6%9%7%3443314%
1386
January1st to 15thNight
19%16%7%12%8%36%44411%
2506
16th to endNight
10%15%7%11%10%5%7%6%5%414%
2688
February1st to 15thNight
9%13%7%11%10%5%7%6%45%17%
2381
16th to endNight
13%19%7%11%8%3443419%
1893
March1st to 15thNight
18%14%48%5%35%345%24%
2147
16th to endNight
13%12%48%7%45%44430%
2013
April1st to 15thNight
26%14%5%6%424335%24%
1796
16th to endNight
20%9%37%423446%32%
1636
May1st to 15thNight
22%9%45%435%435%31%
1482
16th to endNight
26%8%36%41334431%
1486
June1st to 15thNight
21%9%5%7%6%25%447%25%
1260
16th to endNight
20%7%35%6%3446%7%30%
1260
July1st to 15thNight
18%6%46%6%35%5%7%7%28%
1421
16th to endNight
17%7%36%6%2445%7%33%
1514
August1st to 15thNight
18%8%26%5%36%46%7%30%
1453
16th to endNight
18%7%36%6%235%5%7%34%
1811
September1st to 15thNight
23%7%2442335%5%37%
1821
16th to endNight
22%7%25%323345%38%
1825
October1st to 15thNight
24%11%36%5%33345%29%
1928
16th to endNight
29%18%36%5%2433418%
2288
November1st to 15thNight
22%15%5%7%5%35%43422%
2277
16th to endNight
25%16%6%10%6%2333317%
2592
December1st to 15thNight
21%19%8%12%9%3433312%
2700
16th to endNight
20%18%7%11%8%45%43311%
2835

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
76%46%9%3
1433
16th to endDay
69%5%6%11%6%
1536
February1st to 15thDay
71%5%7%8%5%
1478
16th to endDay
69%37%12%6%
1580
March1st to 15thDay
64%46%12%10%1
1800
16th to endDay
60%46%16%11%1
2211
April1st to 15thDay
63%38%12%9%3
2152
16th to endDay
55%49%13%13%2
2323
May1st to 15thDay
55%5%9%16%10%1
2481
16th to endDay
59%6%9%14%8%1
2628
June1st to 15thDay
57%6%9%15%8%1
2700
16th to endDay
61%7%10%11%7%
2700
July1st to 15thDay
58%7%14%14%4
2388
16th to endDay
61%7%11%15%4
2487
August1st to 15thDay
63%9%12%11%2
2480
16th to endDay
55%9%15%15%3
2390
September1st to 15thDay
54%5%16%16%7%
2139
16th to endDay
52%7%16%17%6%
1825
October1st to 15thDay
64%5%9%13%6%
1700
16th to endDay
72%5%9%10%2
1584
November1st to 15thDay
68%6%8%11%4
1581
16th to endDay
72%49%9%2
1365
December1st to 15thDay
77%46%9%1
1260
16th to endDay
74%47%7%6%
1386
January1st to 15thNight
76%46%8%2
2506
16th to endNight
70%5%7%12%3
2688
February1st to 15thNight
66%6%9%12%4
2383
16th to endNight
69%37%12%6%
1893
March1st to 15thNight
62%48%14%8%
2160
16th to endNight
56%5%8%17%9%1
2013
April1st to 15thNight
64%37%13%9%2
1796
16th to endNight
52%6%10%16%13%1
1636
May1st to 15thNight
55%6%10%13%12%1
1482
16th to endNight
56%412%16%8%
1488
June1st to 15thNight
59%7%10%15%6%
1260
16th to endNight
51%9%13%15%10%
1260
July1st to 15thNight
50%9%18%16%5%
1341
16th to endNight
50%8%13%20%6%
1418
August1st to 15thNight
51%10%17%19%2
1443
16th to endNight
47%10%18%19%3
1811
September1st to 15thNight
49%7%14%21%7%
1821
16th to endNight
49%5%16%24%3
1825
October1st to 15thNight
57%6%12%16%6%
1928
16th to endNight
70%5%8%11%3
2288
November1st to 15thNight
65%5%11%11%4
2277
16th to endNight
72%5%7%11%2
2592
December1st to 15thNight
78%48%7%1
2700
16th to endNight
78%46%7%3
2835

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
38%15%36%10%
60
16th to endDay
31%10%34%15%6%1
64
February1st to 15thDay
19%18%41%14%32
87
16th to endDay
27%21%30%13%5%
239
March1st to 15thDay
27%17%31%17%6%
270
16th to endDay
20%19%26%21%10%2
288
April1st to 15thDay
35%17%25%13%5%1
270
16th to endDay
28%21%26%15%5%2
270
May1st to 15thDay
35%14%25%16%8%
288
16th to endDay
34%15%28%16%41
337
June1st to 15thDay
33%9%27%18%8%1
495
16th to endDay
27%11%28%22%8%1
495
July1st to 15thDay
28%10%31%20%7%2
322
16th to endDay
29%10%23%25%9%1
326
August1st to 15thDay
30%5%27%21%8%5%
313
16th to endDay
27%9%26%18%10%6%
332
September1st to 15thDay
32%10%26%17%8%5%
315
16th to endDay
24%15%27%15%13%3
257
October1st to 15thDay
32%13%27%15%9%2
251
16th to endDay
43%11%22%17%31
240
November1st to 15thDay
34%18%26%11%7%1
235
16th to endDay
37%23%26%10%2
69
December1st to 15thDay
36%13%30%16%3
60
16th to endDay
48%21%25%4
64
January1st to 15thNight
27%15%34%17%5%
720
16th to endNight
19%16%32%23%7%
768
February1st to 15thNight
14%15%40%22%6%
704
16th to endNight
29%12%35%16%6%
631
March1st to 15thNight
27%16%30%21%5%
720
16th to endNight
20%17%31%20%7%1
768
April1st to 15thNight
33%12%27%21%4
718
16th to endNight
28%18%29%17%5%
556
May1st to 15thNight
27%11%28%25%6%
402
16th to endNight
31%10%29%21%5%
375
June1st to 15thNight
26%8%32%25%6%1
360
16th to endNight
23%8%29%28%9%
360
July1st to 15thNight
20%7%29%29%13%
340
16th to endNight
21%5%27%32%11%
376
August1st to 15thNight
20%6%24%31%16%
372
16th to endNight
24%6%26%27%14%1
665
September1st to 15thNight
28%5%25%28%9%1
720
16th to endNight
27%9%28%23%9%1
661
October1st to 15thNight
32%8%30%20%6%
660
16th to endNight
42%11%25%15%5%
704
November1st to 15thNight
31%15%28%16%6%1
700
16th to endNight
35%14%25%17%5%
734
December1st to 15thNight
32%15%30%15%5%
750
16th to endNight
31%17%29%17%31
793
Page generated at 2017-09-17 12:05:46. Version ac04

Copyright 2017 A. Danko


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