Ste-Anne-des-Lacs
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ste-Anne-des-Lacs clear sky chart from 2005-11-05 to 2017-09-24.

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%
14640
15%
46915
8%
14608
37%
14608
18%
32178

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%
720
10%
2506
4%
716
24%
716
10%
1874
January16th to endNight
19%
768
13%
2688
6%
768
29%
768
12%
1950
February1st to 15thNight
17%
704
12%
2307
4%
701
28%
701
13%
1707
February16th to endNight
20%
631
15%
1904
6%
631
32%
631
14%
1378
March1st to 15thNight
18%
720
15%
2160
7%
720
27%
720
14%
1586
March16th to endNight
28%
768
21%
1993
8%
768
37%
768
24%
1358
April1st to 15thNight
22%
718
18%
1796
5%
718
30%
718
21%
1313
April16th to endNight
24%
630
18%
1710
6%
630
34%
630
21%
1179
May1st to 15thNight
25%
372
16%
1452
10%
372
38%
372
15%
965
May16th to endNight
27%
375
15%
1497
11%
374
42%
374
18%
947
June1st to 15thNight
27%
360
8%
1440
5%
360
37%
360
14%
978
June16th to endNight
38%
360
9%
1440
11%
360
43%
360
18%
899
July1st to 15thNight
47%
340
13%
1360
17%
340
55%
340
26%
739
July16th to endNight
50%
376
12%
1418
14%
354
55%
354
26%
805
August1st to 15thNight
51%
362
14%
1433
14%
360
57%
360
22%
856
August16th to endNight
49%
751
21%
1897
10%
751
54%
751
38%
1166
September1st to 15thNight
44%
720
16%
1800
7%
720
48%
720
32%
1198
September16th to endNight
45%
693
24%
1894
14%
693
52%
693
34%
1153
October1st to 15thNight
30%
660
21%
1958
10%
660
42%
660
22%
1282
October16th to endNight
24%
704
13%
2249
5%
704
34%
704
16%
1597
November1st to 15thNight
25%
700
19%
2285
10%
700
38%
700
16%
1574
November16th to endNight
22%
720
15%
2520
8%
720
32%
720
12%
1761
December1st to 15thNight
18%
720
12%
2520
4%
720
28%
720
11%
1877
December16th to endNight
13%
768
12%
2688
4%
768
23%
768
9%
2036

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%6%3445%6%31%
48023
Night
16%9%36%5%3445%6%34%
47084
Cloud CoverDay
17%8%36%6%3445%6%32%
48032
Night
16%9%36%5%34446%34%
47090
TransparencyDay
51%311%21%10%1
47710
Night
50%311%22%10%1
46915
SeeingDay
23%12%30%22%9%2
5575
Night
22%11%30%25%9%1
14640

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
18%14%410%7%3444423%
1432
16th to endDay
11%15%6%8%7%3435%428%
1536
February1st to 15thDay
12%14%5%10%7%35%5%4425%
1554
16th to endDay
14%15%5%9%6%3434427%
1568
March1st to 15thDay
16%12%410%8%3434327%
1790
16th to endDay
16%9%35%5%33445%38%
2230
April1st to 15thDay
22%9%35%5%23435%33%
2152
16th to endDay
20%7%35%6%34345%35%
2250
May1st to 15thDay
21%8%37%6%3445%5%29%
2509
16th to endDay
22%7%25%5%35%446%31%
2618
June1st to 15thDay
22%6%36%6%35%5%6%7%27%
2520
16th to endDay
20%7%26%6%46%5%6%7%26%
2520
July1st to 15thDay
14%5%35%6%46%5%7%7%34%
2520
16th to endDay
13%6%26%6%36%7%7%8%31%
2654
August1st to 15thDay
13%5%27%6%5%6%7%6%8%30%
2514
16th to endDay
10%425%5%35%46%8%42%
2292
September1st to 15thDay
17%5%25%43445%7%38%
2160
16th to endDay
15%5%24424346%48%
1924
October1st to 15thDay
21%8%25%5%245%36%33%
1670
16th to endDay
23%10%47%6%25%446%24%
1622
November1st to 15thDay
16%8%36%6%3446%7%31%
1572
16th to endDay
22%10%36%5%24446%29%
1440
December1st to 15thDay
22%14%5%8%5%3443422%
1440
16th to endDay
22%15%5%7%6%3343423%
1536
January1st to 15thNight
15%13%6%8%7%35%45%5%23%
2506
16th to endNight
10%13%5%8%7%46%45%6%28%
2688
February1st to 15thNight
10%12%5%10%8%46%5%45%25%
2305
16th to endNight
14%11%48%8%25%445%30%
1904
March1st to 15thNight
17%10%47%6%45%5%46%28%
2147
16th to endNight
13%9%26%5%3434442%
1993
April1st to 15thNight
23%8%44423345%34%
1796
16th to endNight
20%6%25%5%23446%38%
1710
May1st to 15thNight
20%7%26%6%2444336%
1452
16th to endNight
21%6%24424347%36%
1495
June1st to 15thNight
23%7%35%5%24447%31%
1440
16th to endNight
18%7%146%2446%7%36%
1440
July1st to 15thNight
10%4245%235%6%9%44%
1440
16th to endNight
10%5%25%425%5%7%7%43%
1514
August1st to 15thNight
10%5%25%5%35%6%6%8%39%
1443
16th to endNight
10%42432435%7%50%
1897
September1st to 15thNight
13%5%25%435%45%7%42%
1800
16th to endNight
16%41332345%6%49%
1894
October1st to 15thNight
17%6%36%42445%5%39%
1958
16th to endNight
23%8%36%6%23346%31%
2249
November1st to 15thNight
17%8%36%6%3445%6%33%
2285
16th to endNight
19%12%46%5%24445%30%
2520
December1st to 15thNight
19%13%5%7%5%35%446%25%
2520
16th to endNight
21%15%5%7%5%24335%24%
2688

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
19%13%5%9%7%3444423%
1432
16th to endDay
11%15%5%8%7%3435%428%
1536
February1st to 15thDay
13%14%5%10%8%36%34425%
1554
16th to endDay
15%15%5%9%7%3444427%
1568
March1st to 15thDay
17%11%49%8%45%34327%
1800
16th to endDay
15%9%35%434346%38%
2229
April1st to 15thDay
22%9%35%43344433%
2152
16th to endDay
20%7%36%5%33445%36%
2250
May1st to 15thDay
21%8%36%6%33446%30%
2509
16th to endDay
22%6%245%35%45%6%31%
2618
June1st to 15thDay
22%6%25%6%35%5%5%7%28%
2520
16th to endDay
19%7%35%6%46%6%5%7%27%
2520
July1st to 15thDay
13%5%25%6%36%5%6%7%35%
2520
16th to endDay
12%6%26%5%46%6%7%9%33%
2654
August1st to 15thDay
13%5%26%7%46%7%6%8%31%
2514
16th to endDay
10%325%5%345%5%9%43%
2292
September1st to 15thDay
17%5%15%5%245%48%39%
2160
16th to endDay
15%5%23324346%48%
1924
October1st to 15thDay
21%8%25%5%23436%34%
1670
16th to endDay
23%10%37%6%34436%25%
1622
November1st to 15thDay
15%7%46%5%45%47%7%31%
1572
16th to endDay
22%10%36%5%24445%30%
1440
December1st to 15thDay
22%14%5%7%6%2444423%
1440
16th to endDay
23%14%5%7%5%2434323%
1536
January1st to 15thNight
15%14%5%9%6%345%5%5%23%
2506
16th to endNight
10%12%5%9%6%46%45%5%28%
2688
February1st to 15thNight
10%12%5%10%8%35%6%5%5%25%
2298
16th to endNight
15%10%48%6%45%445%30%
1904
March1st to 15thNight
17%10%5%6%6%35%445%29%
2160
16th to endNight
14%8%26%433445%41%
1993
April1st to 15thNight
24%6%45%5%23435%34%
1796
16th to endNight
20%6%25%424346%38%
1710
May1st to 15thNight
19%7%36%6%2444435%
1452
16th to endNight
22%5%2442435%6%37%
1495
June1st to 15thNight
23%7%35%5%33446%31%
1440
16th to endNight
18%5%25%5%25%45%8%36%
1440
July1st to 15thNight
10%4244245%6%9%44%
1440
16th to endNight
10%5%244246%6%8%43%
1514
August1st to 15thNight
10%5%35%6%45%5%6%8%40%
1443
16th to endNight
11%424424447%50%
1897
September1st to 15thNight
13%5%25%435%45%7%42%
1800
16th to endNight
16%41332345%6%50%
1894
October1st to 15thNight
17%6%35%42345%6%38%
1958
16th to endNight
23%7%36%433446%31%
2249
November1st to 15thNight
18%8%36%5%3445%6%33%
2285
16th to endNight
20%11%45%5%2345%430%
2520
December1st to 15thNight
19%13%5%6%5%34445%25%
2520
16th to endNight
21%14%5%7%5%24335%24%
2688

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
63%29%16%7%
1433
16th to endDay
58%28%19%9%1
1536
February1st to 15thDay
61%28%21%5%
1556
16th to endDay
60%18%17%9%1
1568
March1st to 15thDay
60%19%16%10%1
1800
16th to endDay
47%29%19%16%4
2230
April1st to 15thDay
53%27%20%13%3
2152
16th to endDay
51%27%20%13%4
2250
May1st to 15thDay
54%27%19%13%2
2509
16th to endDay
52%310%20%12%1
2622
June1st to 15thDay
53%311%18%10%1
2520
16th to endDay
53%411%21%8%1
2520
July1st to 15thDay
42%415%26%11%
2371
16th to endDay
44%416%23%9%
2487
August1st to 15thDay
48%416%22%8%
2500
16th to endDay
37%417%28%12%
2292
September1st to 15thDay
43%312%26%13%
2160
16th to endDay
37%213%35%11%
1924
October1st to 15thDay
51%210%23%11%
1670
16th to endDay
61%112%17%7%
1622
November1st to 15thDay
49%316%19%11%
1572
16th to endDay
55%311%20%7%
1440
December1st to 15thDay
64%312%15%4
1440
16th to endDay
64%39%13%8%
1536
January1st to 15thNight
61%310%17%6%
2506
16th to endNight
58%38%18%9%1
2688
February1st to 15thNight
59%210%20%6%
2307
16th to endNight
56%28%19%11%1
1904
March1st to 15thNight
57%28%19%10%1
2160
16th to endNight
46%29%20%17%3
1993
April1st to 15thNight
52%25%21%15%1
1796
16th to endNight
47%38%20%16%3
1710
May1st to 15thNight
52%27%18%14%4
1452
16th to endNight
47%39%23%15%1
1497
June1st to 15thNight
53%310%20%10%
1440
16th to endNight
45%412%22%14%1
1440
July1st to 15thNight
33%5%16%29%14%
1360
16th to endNight
37%418%25%13%
1418
August1st to 15thNight
40%5%18%25%10%
1433
16th to endNight
33%317%32%12%
1897
September1st to 15thNight
40%312%29%13%
1800
16th to endNight
35%312%36%13%
1894
October1st to 15thNight
45%311%26%12%
1958
16th to endNight
54%213%20%8%
2249
November1st to 15thNight
51%312%21%9%2
2285
16th to endNight
55%211%22%7%
2520
December1st to 15thNight
60%311%19%4
2520
16th to endNight
63%29%15%7%
2688

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%28%20%5%
60
16th to endDay
26%17%37%14%31
64
February1st to 15thDay
37%24%29%6%1
87
16th to endDay
27%16%29%20%5%
227
March1st to 15thDay
27%18%28%21%4
270
16th to endDay
24%14%30%17%9%3
288
April1st to 15thDay
31%14%30%14%7%1
270
16th to endDay
24%16%30%20%7%1
270
May1st to 15thDay
32%11%29%18%5%1
288
16th to endDay
26%14%31%19%7%
331
June1st to 15thDay
27%12%33%18%6%
315
16th to endDay
23%8%32%27%6%1
315
July1st to 15thDay
15%8%38%22%11%3
305
16th to endDay
12%330%35%15%1
326
August1st to 15thDay
15%6%27%32%15%2
313
16th to endDay
12%5%32%26%13%9%
332
September1st to 15thDay
19%5%27%21%19%6%
315
16th to endDay
17%9%22%25%15%9%
287
October1st to 15thDay
24%13%24%21%14%1
255
16th to endDay
30%11%27%23%6%
247
November1st to 15thDay
19%18%31%19%9%1
226
16th to endDay
35%11%31%20%1
60
December1st to 15thDay
23%20%35%18%3
60
16th to endDay
43%26%26%3
64
January1st to 15thNight
24%15%33%21%5%
720
16th to endNight
17%15%35%23%7%
768
February1st to 15thNight
18%15%39%20%5%
704
16th to endNight
23%13%34%22%5%
631
March1st to 15thNight
25%13%35%22%3
720
16th to endNight
19%13%33%26%7%
768
April1st to 15thNight
29%12%29%24%4
718
16th to endNight
25%13%31%21%7%
630
May1st to 15thNight
22%9%33%24%7%1
372
16th to endNight
23%8%35%25%7%
375
June1st to 15thNight
28%8%27%26%8%
360
16th to endNight
22%327%31%13%
360
July1st to 15thNight
9%8%29%36%15%1
340
16th to endNight
11%426%42%13%1
376
August1st to 15thNight
14%321%38%21%1
362
16th to endNight
13%6%24%33%19%2
751
September1st to 15thNight
16%5%28%33%14%1
720
16th to endNight
17%7%24%25%20%3
693
October1st to 15thNight
22%11%28%26%10%1
660
16th to endNight
30%11%27%23%6%
704
November1st to 15thNight
23%11%30%23%9%1
700
16th to endNight
28%15%25%19%9%1
720
December1st to 15thNight
28%17%27%20%5%
720
16th to endNight
33%13%29%18%31
768
Page generated at 2017-09-25 09:02:22. Version ac04

Copyright 2017 A. Danko


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