Sept-Îles
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sept-Îles clear sky chart from 2005-11-06 to 2024-01-12.

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
28%
22854
13%
74731
6%
22805
36%
22805
15%
52859

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 10thNight
20%
850
15%
2838
4%
847
33%
847
13%
2057
January11th to 20thNight
20%
808
14%
2722
4%
808
31%
808
13%
1928
January21st to endNight
23%
814
19%
2822
8%
814
39%
814
16%
1882
February1st to 10thNight
23%
720
17%
2394
6%
720
37%
720
16%
1626
February11th to 20thNight
20%
701
13%
2276
4%
700
33%
700
13%
1628
February21st to endNight
24%
592
16%
1891
5%
592
38%
592
15%
1333
March1st to 10thNight
23%
720
17%
2097
7%
720
34%
720
15%
1524
March11th to 20thNight
24%
720
19%
1980
7%
720
35%
720
17%
1443
March21st to endNight
24%
792
18%
2178
5%
792
34%
792
16%
1563
April1st to 10thNight
20%
594
14%
1751
4%
594
28%
594
13%
1298
April11th to 20thNight
25%
534
19%
1598
7%
534
36%
534
19%
1089
April21st to endNight
26%
540
15%
1620
7%
540
35%
540
17%
1150
May1st to 10thNight
31%
540
11%
1503
6%
540
37%
540
19%
1124
May11th to 20thNight
32%
431
12%
1316
5%
431
40%
431
17%
941
May21st to endNight
31%
388
9%
1356
5%
388
36%
388
14%
964
June1st to 10thNight
36%
360
6%
1260
3%
360
39%
360
17%
854
June11th to 20thNight
45%
360
4%
1260
2%
360
45%
360
18%
851
June21st to endNight
39%
360
2%
1260
1%
360
40%
360
15%
909
July1st to 10thNight
39%
350
4%
1225
2%
350
41%
350
19%
829
July11th to 20thNight
47%
348
6%
1218
6%
348
48%
348
18%
837
July21st to endNight
47%
394
10%
1300
10%
372
50%
372
19%
900
August1st to 10thNight
49%
461
7%
1494
7%
459
52%
459
18%
1053
August11th to 20thNight
44%
532
9%
1596
7%
532
47%
532
19%
1149
August21st to endNight
41%
594
14%
1782
9%
594
46%
594
20%
1217
September1st to 10thNight
37%
540
16%
1741
9%
540
43%
540
21%
1153
September11th to 20thNight
39%
697
15%
1957
7%
697
46%
697
23%
1338
September21st to endNight
36%
720
19%
1980
10%
720
43%
720
24%
1352
October1st to 10thNight
28%
720
19%
2150
8%
720
39%
720
18%
1489
October11th to 20thNight
28%
720
13%
2164
7%
720
34%
720
15%
1620
October21st to endNight
25%
799
13%
2588
6%
799
32%
799
13%
1905
November1st to 10thNight
23%
830
12%
2593
4%
830
31%
830
13%
1917
November11th to 20thNight
23%
850
13%
2660
5%
850
33%
850
13%
1982
November21st to endNight
19%
850
12%
2752
3%
850
30%
850
11%
2086
December1st to 10thNight
20%
850
14%
2850
5%
850
31%
850
13%
2052
December11th to 20thNight
15%
850
15%
3438
6%
848
27%
848
10%
2430
December21st to endNight
19%
925
10%
5121
4%
906
30%
906
8%
3386

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
20%9%36%5%35%5%5%6%32%
74633
Night
19%10%47%5%3445%6%33%
75088
TransparencyDay
53%5%11%20%10%1
74315
Night
53%411%20%11%1
74941
SeeingDay
27%14%29%21%8%2
15092
Night
25%12%25%27%10%1
22867

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 10thDay
13%17%410%7%44445%29%
1327
11th to 20thDay
15%13%5%8%5%23235%37%
1267
21st to endDay
9%12%6%8%6%35%45%6%36%
1531
February1st to 10thDay
8%11%49%9%4445%7%35%
1565
11th to 20thDay
9%16%6%9%7%35%5%5%6%29%
1573
21st to endDay
8%12%6%9%5%35%5%6%7%34%
1363
March1st to 10thDay
11%14%6%8%5%3445%6%34%
1858
11th to 20thDay
15%13%5%7%5%44445%34%
1980
21st to endDay
14%15%5%7%6%34345%34%
2178
April1st to 10thDay
21%11%47%7%5%5%45%5%26%
2206
11th to 20thDay
14%11%38%5%3445%7%37%
2312
21st to endDay
24%9%35%434446%34%
2340
May1st to 10thDay
25%8%36%6%345%5%6%30%
2456
11th to 20thDay
23%7%37%6%3445%6%32%
2592
21st to endDay
24%5%35%6%345%5%6%33%
2919
June1st to 10thDay
25%7%36%5%35%5%45%31%
2700
11th to 20thDay
21%6%25%5%35%6%6%7%33%
2700
21st to endDay
28%6%25%5%345%6%7%28%
2700
July1st to 10thDay
22%7%26%6%345%7%7%31%
2700
11th to 20thDay
19%6%36%5%35%5%7%8%34%
2700
21st to endDay
22%6%35%6%36%6%6%9%29%
2941
August1st to 10thDay
21%7%36%5%35%6%6%8%29%
2416
11th to 20thDay
22%7%35%5%345%5%8%33%
2304
21st to endDay
20%6%37%6%45%5%6%7%31%
2574
September1st to 10thDay
21%5%26%5%35%45%6%37%
2219
11th to 20thDay
26%6%24424446%38%
2001
21st to endDay
23%6%35%4235%47%38%
1980
October1st to 10thDay
21%6%25%5%3445%6%38%
1810
11th to 20thDay
27%8%26%5%35%5%48%28%
1795
21st to endDay
30%9%36%5%25%44428%
1767
November1st to 10thDay
23%9%25%7%35%45%6%31%
1485
11th to 20thDay
21%13%45%5%35%5%46%29%
1520
21st to endDay
19%15%5%6%6%44445%29%
1425
December1st to 10thDay
17%13%5%7%43446%7%29%
1330
11th to 20thDay
18%13%49%42344434%
1668
21st to endDay
12%14%5%7%5%3445%7%37%
2431
January1st to 10thNight
14%14%6%9%5%445%45%29%
2838
11th to 20thNight
15%15%5%8%5%3445%5%32%
2722
21st to endNight
9%13%6%9%7%34446%36%
2822
February1st to 10thNight
8%11%6%9%7%45%446%35%
2394
11th to 20thNight
11%17%6%8%6%3445%5%31%
2273
21st to endNight
10%12%6%9%6%45%5%5%5%32%
1891
March1st to 10thNight
12%13%6%9%6%4445%5%32%
2088
11th to 20thNight
14%13%6%7%6%345%45%33%
1979
21st to endNight
14%14%47%6%3445%6%34%
2178
April1st to 10thNight
22%12%47%6%3444430%
1751
11th to 20thNight
20%8%35%434445%38%
1598
21st to endNight
26%9%345%3332437%
1620
May1st to 10thNight
25%8%36%5%335%6%6%29%
1503
11th to 20thNight
22%8%36%5%44445%33%
1315
21st to endNight
23%6%46%436%45%6%32%
1356
June1st to 10thNight
26%6%345%245%6%6%33%
1260
11th to 20thNight
22%7%35%435%5%7%6%33%
1260
21st to endNight
27%7%27%5%345%6%6%29%
1260
July1st to 10thNight
22%8%35%4345%7%9%31%
1260
11th to 20thNight
21%7%35%6%445%5%6%34%
1260
21st to endNight
20%6%46%6%445%7%7%32%
1377
August1st to 10thNight
21%5%36%5%45%5%6%8%31%
1503
11th to 20thNight
22%8%36%5%35%5%6%6%32%
1596
21st to endNight
19%6%35%6%35%6%6%8%34%
1782
September1st to 10thNight
22%6%35%4246%46%39%
1741
11th to 20thNight
23%6%244345%46%40%
1957
21st to endNight
21%6%24433447%41%
1980
October1st to 10thNight
23%6%36%5%2345%6%37%
2150
11th to 20thNight
28%8%37%5%34445%30%
2164
21st to endNight
28%10%35%433446%30%
2588
November1st to 10thNight
25%10%25%5%35%5%5%6%30%
2593
11th to 20thNight
22%13%5%5%5%35%45%5%28%
2660
21st to endNight
20%16%5%8%5%34445%27%
2752
December1st to 10thNight
20%14%5%6%5%3435%5%32%
2850
11th to 20thNight
23%11%5%6%423335%34%
3531
21st to endNight
12%12%5%9%6%46%5%5%6%31%
5236

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 10thDay
60%39%18%9%1
1328
11th to 20thDay
53%210%22%10%2
1267
21st to endDay
51%38%23%14%2
1531
February1st to 10thDay
50%410%21%12%3
1565
11th to 20thDay
56%410%20%9%1
1581
21st to endDay
49%5%7%24%13%2
1363
March1st to 10thDay
52%49%20%12%3
1862
11th to 20thDay
53%47%17%15%3
1980
21st to endDay
55%37%16%15%4
2178
April1st to 10thDay
61%5%7%13%12%2
2206
11th to 20thDay
49%5%8%22%14%2
2312
21st to endDay
53%410%18%13%2
2340
May1st to 10thDay
56%6%7%21%10%1
2456
11th to 20thDay
52%5%10%21%11%1
2596
21st to endDay
51%7%9%20%12%1
2919
June1st to 10thDay
55%5%9%20%10%2
2700
11th to 20thDay
50%7%12%18%11%2
2700
21st to endDay
55%7%11%19%8%1
2700
July1st to 10thDay
51%8%15%18%8%1
2625
11th to 20thDay
48%7%14%21%10%
2619
21st to endDay
51%7%16%20%5%
2777
August1st to 10thDay
53%7%20%16%4
2401
11th to 20thDay
50%8%15%21%5%
2304
21st to endDay
52%7%15%21%5%
2574
September1st to 10thDay
48%6%14%23%9%
2219
11th to 20thDay
48%6%14%24%7%
2001
21st to endDay
47%7%11%24%11%
1980
October1st to 10thDay
47%6%14%21%11%2
1810
11th to 20thDay
56%6%13%20%5%
1795
21st to endDay
62%49%14%10%1
1767
November1st to 10thDay
54%7%13%17%9%1
1485
11th to 20thDay
59%6%11%18%6%
1520
21st to endDay
59%410%18%10%
1425
December1st to 10thDay
56%5%13%22%41
1330
11th to 20thDay
54%48%21%12%1
1668
21st to endDay
49%313%19%11%5%
2431
January1st to 10thNight
57%311%19%9%1
2838
11th to 20thNight
56%310%21%9%2
2722
21st to endNight
50%37%21%17%1
2822
February1st to 10thNight
51%38%20%14%3
2394
11th to 20thNight
55%39%19%12%1
2276
21st to endNight
54%37%20%15%2
1891
March1st to 10thNight
55%46%18%16%1
2097
11th to 20thNight
54%36%21%15%2
1980
21st to endNight
52%47%18%16%3
2178
April1st to 10thNight
58%37%13%15%3
1751
11th to 20thNight
48%49%18%17%3
1598
21st to endNight
54%28%16%18%2
1620
May1st to 10thNight
55%5%9%20%10%1
1503
11th to 20thNight
54%39%20%13%1
1316
21st to endNight
54%6%8%20%11%1
1357
June1st to 10thNight
50%5%10%22%12%2
1260
11th to 20thNight
49%5%12%19%13%2
1260
21st to endNight
56%5%12%18%10%
1260
July1st to 10thNight
48%6%17%22%7%
1225
11th to 20thNight
49%6%11%22%10%1
1218
21st to endNight
50%6%15%22%7%
1300
August1st to 10thNight
50%7%21%17%5%
1494
11th to 20thNight
53%5%17%20%6%
1596
21st to endNight
47%6%15%25%5%
1782
September1st to 10thNight
46%5%12%29%8%
1741
11th to 20thNight
46%415%26%8%1
1957
21st to endNight
45%5%12%27%11%
1980
October1st to 10thNight
50%311%24%10%1
2150
11th to 20thNight
58%411%20%7%
2164
21st to endNight
58%410%20%6%1
2588
November1st to 10thNight
56%6%11%17%9%1
2593
11th to 20thNight
59%312%18%7%
2660
21st to endNight
61%411%16%7%
2752
December1st to 10thNight
57%313%20%8%
2850
11th to 20thNight
56%37%24%10%1
3532
21st to endNight
54%412%17%10%4
5236

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 10thDay
22%13%35%19%10%1
180
11th to 20thDay
22%15%34%18%10%2
162
21st to endDay
20%21%27%24%7%1
176
February1st to 10thDay
18%16%38%20%8%
285
11th to 20thDay
14%22%37%19%5%1
336
21st to endDay
18%18%35%22%6%2
294
March1st to 10thDay
21%19%33%19%6%2
420
11th to 20thDay
23%12%34%20%9%2
420
21st to endDay
26%22%27%17%6%2
462
April1st to 10thDay
28%25%27%14%5%1
420
11th to 20thDay
25%15%36%18%41
412
21st to endDay
30%15%30%16%7%1
420
May1st to 10thDay
29%13%31%18%8%2
539
11th to 20thDay
26%16%28%20%8%2
624
21st to endDay
30%16%27%19%7%1
680
June1st to 10thDay
30%12%29%21%7%1
630
11th to 20thDay
26%14%27%19%11%2
630
21st to endDay
30%9%27%24%9%2
630
July1st to 10thDay
25%11%29%23%10%2
620
11th to 20thDay
23%9%28%27%11%2
618
21st to endDay
27%7%25%26%13%2
685
August1st to 10thDay
26%9%24%29%9%3
476
11th to 20thDay
24%10%30%26%8%2
439
21st to endDay
25%11%30%23%9%2
495
September1st to 10thDay
28%13%31%21%6%2
450
11th to 20thDay
30%12%31%17%7%2
450
21st to endDay
26%17%30%17%8%2
450
October1st to 10thDay
25%21%26%19%8%1
365
11th to 20thDay
33%13%26%16%9%3
360
21st to endDay
39%12%21%16%10%2
396
November1st to 10thDay
32%17%25%19%5%1
365
11th to 20thDay
29%16%28%19%7%1
370
21st to endDay
29%18%28%17%8%
275
December1st to 10thDay
26%9%23%29%11%2
180
11th to 20thDay
22%24%29%17%7%
180
21st to endDay
27%17%31%20%5%1
198
January1st to 10thNight
21%13%32%27%7%1
850
11th to 20thNight
26%15%28%25%6%
808
21st to endNight
15%15%34%28%7%
814
February1st to 10thNight
14%17%35%25%9%
720
11th to 20thNight
21%17%30%21%10%1
703
21st to endNight
18%15%31%25%9%3
592
March1st to 10thNight
19%15%32%24%8%2
720
11th to 20thNight
22%13%29%26%8%1
720
21st to endNight
21%18%27%24%10%1
792
April1st to 10thNight
30%14%26%24%6%1
594
11th to 20thNight
23%13%31%22%10%1
534
21st to endNight
31%10%24%25%8%2
540
May1st to 10thNight
29%6%23%32%8%2
540
11th to 20thNight
26%8%23%30%10%2
431
21st to endNight
27%9%22%31%9%1
389
June1st to 10thNight
30%6%20%33%10%1
360
11th to 20thNight
26%7%15%34%16%2
360
21st to endNight
29%5%18%33%13%2
360
July1st to 10thNight
24%5%22%31%17%1
350
11th to 20thNight
23%5%16%38%16%1
348
21st to endNight
22%5%13%40%19%1
394
August1st to 10thNight
25%5%11%33%23%3
461
11th to 20thNight
25%6%13%36%19%1
532
21st to endNight
22%6%21%30%18%2
594
September1st to 10thNight
24%8%23%33%11%1
540
11th to 20thNight
26%8%19%32%13%2
697
21st to endNight
26%8%23%31%11%1
720
October1st to 10thNight
28%13%23%26%10%1
720
11th to 20thNight
33%8%22%22%14%1
720
21st to endNight
36%8%22%24%10%1
799
November1st to 10thNight
33%12%25%23%6%1
830
11th to 20thNight
29%13%26%24%7%1
850
21st to endNight
30%13%25%24%7%1
850
December1st to 10thNight
27%14%26%22%10%1
850
11th to 20thNight
25%18%33%18%6%
850
21st to endNight
22%16%32%21%8%1
935
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