Centre écologique de Port-au-Saumon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Centre écologique de Port-au-Saumon clear sky chart from 2005-11-05 to 2017-08-12.

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
26%
14471
11%
46459
6%
14439
32%
14439
13%
34532

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
14%
732
9%
2578
3%
728
21%
728
8%
2045
January16th to endNight
25%
768
11%
2688
5%
768
33%
768
9%
2043
February1st to 15thNight
19%
704
9%
2382
4%
701
26%
701
11%
1789
February16th to endNight
20%
631
10%
1896
4%
631
28%
631
11%
1493
March1st to 15thNight
21%
720
13%
2130
8%
720
27%
720
14%
1602
March16th to endNight
27%
768
17%
2064
8%
768
34%
768
18%
1500
April1st to 15thNight
21%
676
14%
1754
6%
676
26%
676
14%
1368
April16th to endNight
25%
540
16%
1620
7%
540
33%
540
15%
1137
May1st to 15thNight
28%
479
11%
1559
8%
479
34%
479
13%
1131
May16th to endNight
25%
375
10%
1359
4%
374
36%
374
11%
1014
June1st to 15thNight
29%
360
6%
1260
4%
360
32%
360
13%
897
June16th to endNight
33%
360
5%
1260
2%
360
37%
360
14%
899
July1st to 15thNight
39%
340
7%
1207
7%
340
42%
340
17%
832
July16th to endNight
44%
376
8%
1418
10%
354
52%
354
15%
957
August1st to 15thNight
48%
426
9%
1475
9%
424
52%
424
16%
1025
August16th to endNight
46%
532
12%
1582
7%
532
48%
532
21%
1082
September1st to 15thNight
35%
660
9%
1719
4%
660
38%
660
21%
1244
September16th to endNight
38%
657
17%
1815
11%
657
42%
657
27%
1193
October1st to 15thNight
29%
660
15%
1911
7%
660
37%
660
19%
1343
October16th to endNight
22%
704
9%
2288
5%
704
28%
704
13%
1754
November1st to 15thNight
25%
703
12%
2295
9%
703
30%
703
12%
1707
November16th to endNight
24%
750
9%
2619
5%
750
30%
750
9%
2001
December1st to 15thNight
13%
750
6%
2700
1%
750
20%
750
7%
2194
December16th to endNight
17%
800
9%
2880
3%
800
24%
800
7%
2282

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
17%8%36%5%35%5%5%7%31%
47530
Night
17%9%46%5%35%45%6%31%
46620
TransparencyDay
50%8%14%18%7%
47209
Night
55%7%12%17%7%
46459
SeeingDay
22%16%25%22%10%2
6183
Night
21%20%25%24%8%
14471

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%13%5%7%7%35%5%5%7%25%
1358
16th to endDay
9%10%6%8%7%5%7%5%6%5%26%
1536
February1st to 15thDay
6%13%6%6%10%6%7%7%5%6%24%
1479
16th to endDay
14%12%410%6%45%5%5%5%26%
1577
March1st to 15thDay
15%9%5%7%6%26%5%45%29%
1820
16th to endDay
12%12%5%7%6%24446%33%
2157
April1st to 15thDay
21%8%36%5%24445%32%
2194
16th to endDay
20%9%25%5%33335%36%
2340
May1st to 15thDay
20%6%25%5%34446%34%
2403
16th to endDay
20%6%35%6%345%5%7%29%
2754
June1st to 15thDay
20%6%26%435%5%6%7%29%
2700
16th to endDay
19%6%35%7%45%47%7%28%
2700
July1st to 15thDay
15%5%25%5%36%5%7%11%31%
2679
16th to endDay
14%5%25%5%35%6%6%8%34%
2654
August1st to 15thDay
13%6%26%6%46%6%7%9%29%
2378
16th to endDay
12%425%435%5%5%10%39%
2267
September1st to 15thDay
16%6%25%5%3445%6%39%
1911
16th to endDay
15%42432445%8%44%
1815
October1st to 15thDay
20%7%25%43335%6%36%
1716
16th to endDay
23%9%35%5%35%445%27%
1584
November1st to 15thDay
17%11%37%5%5%5%445%28%
1563
16th to endDay
19%11%6%7%5%24445%27%
1341
December1st to 15thDay
21%14%45%6%35%335%25%
1260
16th to endDay
20%14%49%7%3432426%
1344
January1st to 15thNight
14%12%49%8%36%5%5%6%23%
2578
16th to endNight
11%11%5%8%7%46%6%6%7%25%
2688
February1st to 15thNight
7%12%48%8%45%5%5%6%28%
2381
16th to endNight
15%13%5%10%6%34445%27%
1896
March1st to 15thNight
13%13%47%4345%46%32%
2117
16th to endNight
12%11%46%433446%37%
2064
April1st to 15thNight
20%11%47%5%3433431%
1754
16th to endNight
23%8%24323445%38%
1620
May1st to 15thNight
24%8%35%5%135%45%31%
1559
16th to endNight
23%6%36%5%35%44430%
1357
June1st to 15thNight
19%7%37%6%345%5%6%30%
1260
16th to endNight
20%6%36%6%346%5%8%30%
1260
July1st to 15thNight
17%6%36%5%345%5%8%34%
1278
16th to endNight
13%5%26%5%36%5%6%7%37%
1514
August1st to 15thNight
14%5%26%6%46%5%6%6%34%
1485
16th to endNight
13%3245%35%6%5%9%39%
1582
September1st to 15thNight
17%6%245%25%5%5%6%38%
1719
16th to endNight
19%423313345%48%
1815
October1st to 15thNight
18%5%25%424446%39%
1911
16th to endNight
24%8%35%424445%31%
2288
November1st to 15thNight
20%10%36%324447%32%
2295
16th to endNight
18%10%46%5%35%45%6%29%
2619
December1st to 15thNight
20%14%5%7%5%25%44425%
2700
16th to endNight
19%11%5%7%7%36%45%5%24%
2880

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%8%11%14%4
1359
16th to endDay
59%6%12%13%7%
1536
February1st to 15thDay
59%7%14%11%6%1
1482
16th to endDay
61%47%16%7%
1577
March1st to 15thDay
55%6%10%13%12%1
1830
16th to endDay
52%5%10%20%10%1
2157
April1st to 15thDay
53%5%10%18%8%3
2194
16th to endDay
49%5%10%19%13%1
2340
May1st to 15thDay
48%7%13%19%10%
2403
16th to endDay
51%10%11%19%6%
2758
June1st to 15thDay
50%9%12%18%8%
2700
16th to endDay
50%9%15%16%7%
2700
July1st to 15thDay
43%9%20%20%6%
2521
16th to endDay
43%11%18%19%7%
2487
August1st to 15thDay
42%11%24%17%4
2364
16th to endDay
37%9%23%24%5%
2267
September1st to 15thDay
42%6%18%22%9%
1911
16th to endDay
37%7%17%27%9%
1815
October1st to 15thDay
48%7%16%18%8%
1716
16th to endDay
58%8%12%16%3
1584
November1st to 15thDay
54%9%13%18%4
1563
16th to endDay
60%8%12%14%4
1341
December1st to 15thDay
66%5%12%10%4
1260
16th to endDay
66%5%10%12%5%
1344
January1st to 15thNight
63%8%10%13%4
2578
16th to endNight
60%5%10%17%5%
2688
February1st to 15thNight
56%8%12%16%5%
2382
16th to endNight
63%49%14%7%
1896
March1st to 15thNight
57%5%10%16%9%1
2130
16th to endNight
50%6%10%22%9%1
2064
April1st to 15thNight
59%46%14%12%1
1754
16th to endNight
49%6%8%19%14%1
1620
May1st to 15thNight
55%5%10%17%10%1
1559
16th to endNight
56%7%9%16%8%1
1359
June1st to 15thNight
53%6%12%17%8%1
1260
16th to endNight
51%8%14%16%8%
1260
July1st to 15thNight
45%10%16%21%6%
1207
16th to endNight
44%11%16%19%8%
1418
August1st to 15thNight
45%10%18%20%4
1475
16th to endNight
40%11%19%21%5%
1582
September1st to 15thNight
45%9%15%19%8%1
1719
16th to endNight
40%6%15%26%10%
1815
October1st to 15thNight
47%6%13%23%8%
1911
16th to endNight
57%8%12%16%4
2288
November1st to 15thNight
53%9%13%14%6%
2295
16th to endNight
59%8%13%13%5%
2619
December1st to 15thNight
66%7%11%11%2
2700
16th to endNight
64%7%11%11%4
2880

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
16%20%40%23%
60
16th to endDay
12%14%40%20%12%
64
February1st to 15thDay
18%15%32%25%7%
140
16th to endDay
26%18%29%17%6%1
238
March1st to 15thDay
23%20%25%19%9%1
270
16th to endDay
19%19%25%20%12%2
288
April1st to 15thDay
26%23%23%18%5%1
270
16th to endDay
23%21%24%21%6%2
270
May1st to 15thDay
26%19%18%25%7%2
288
16th to endDay
22%20%27%19%8%1
468
June1st to 15thDay
23%18%24%21%10%1
495
16th to endDay
21%14%26%22%13%1
495
July1st to 15thDay
19%14%23%26%13%2
455
16th to endDay
15%14%20%32%15%1
326
August1st to 15thDay
16%9%22%26%19%5%
297
16th to endDay
17%13%24%23%16%5%
268
September1st to 15thDay
22%11%20%27%14%4
255
16th to endDay
18%14%27%22%12%5%
254
October1st to 15thDay
23%14%28%19%11%3
242
16th to endDay
33%16%24%18%5%1
240
November1st to 15thDay
24%17%27%21%7%1
235
16th to endDay
29%21%17%21%8%
141
December1st to 15thDay
31%6%41%13%5%1
60
16th to endDay
34%12%39%14%
64
January1st to 15thNight
19%23%33%18%4
732
16th to endNight
15%22%25%27%7%
768
February1st to 15thNight
14%23%32%21%7%
704
16th to endNight
24%22%24%21%5%1
631
March1st to 15thNight
20%23%28%20%5%
720
16th to endNight
18%22%26%24%7%
768
April1st to 15thNight
24%23%25%19%5%
676
16th to endNight
24%22%23%22%6%
540
May1st to 15thNight
26%21%19%23%8%
479
16th to endNight
22%22%23%22%8%
375
June1st to 15thNight
21%18%23%28%7%1
360
16th to endNight
19%18%20%31%10%
360
July1st to 15thNight
19%14%22%30%12%1
340
16th to endNight
15%18%15%37%12%
376
August1st to 15thNight
16%12%12%33%23%1
426
16th to endNight
14%12%22%34%14%
532
September1st to 15thNight
18%14%23%30%10%1
660
16th to endNight
21%12%24%30%10%1
657
October1st to 15thNight
22%16%27%25%8%1
660
16th to endNight
28%15%28%17%8%
704
November1st to 15thNight
24%21%24%21%6%
703
16th to endNight
20%27%22%22%7%1
750
December1st to 15thNight
26%23%28%16%4
750
16th to endNight
25%25%23%18%6%1
800
Page generated at 2017-08-13 14:16:32. Version ac04

Copyright 2017 A. Danko


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