Pointe-au-Chêne
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pointe-au-Chêne 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%
22533
9%
74719
5%
22491
32%
22491
8%
61143

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
12%
760
5%
2649
1%
757
17%
757
3%
2352
January11th to 20thNight
17%
728
5%
2546
2%
728
20%
728
4%
2247
January21st to endNight
19%
792
8%
2763
5%
792
24%
792
7%
2294
February1st to 10thNight
17%
720
7%
2340
2%
720
23%
720
6%
1989
February11th to 20thNight
17%
702
8%
2227
2%
700
24%
700
6%
1894
February21st to endNight
19%
592
9%
1776
4%
592
27%
592
7%
1489
March1st to 10thNight
19%
720
10%
2160
5%
720
25%
720
7%
1817
March11th to 20thNight
20%
720
9%
2039
4%
720
26%
720
8%
1708
March21st to endNight
26%
792
14%
2021
5%
792
32%
792
12%
1627
April1st to 10thNight
21%
720
9%
1800
2%
720
24%
720
11%
1507
April11th to 20thNight
24%
711
12%
1775
3%
711
29%
711
12%
1435
April21st to endNight
24%
609
11%
1689
5%
609
29%
609
11%
1380
May1st to 10thNight
28%
360
10%
1440
7%
360
36%
360
9%
1110
May11th to 20thNight
32%
354
15%
1416
13%
354
43%
354
11%
1037
May21st to endNight
32%
389
11%
1551
9%
388
42%
388
10%
1160
June1st to 10thNight
34%
360
6%
1440
4%
360
41%
360
8%
1139
June11th to 20thNight
40%
360
8%
1440
10%
360
45%
360
9%
1097
June21st to endNight
40%
360
7%
1440
10%
360
44%
360
8%
1144
July1st to 10thNight
48%
350
8%
1400
11%
350
53%
350
12%
1031
July11th to 20thNight
52%
348
9%
1392
14%
348
55%
348
11%
1042
July21st to endNight
48%
394
8%
1486
10%
372
50%
372
10%
1120
August1st to 10thNight
54%
358
8%
1422
7%
356
58%
356
11%
1076
August11th to 20thNight
53%
542
13%
1606
9%
542
56%
542
18%
1198
August21st to endNight
47%
792
9%
1980
4%
792
49%
792
17%
1568
September1st to 10thNight
43%
720
9%
1800
3%
720
45%
720
16%
1429
September11th to 20thNight
50%
720
14%
1837
7%
720
53%
720
17%
1418
September21st to endNight
43%
720
12%
1980
8%
720
45%
720
15%
1568
October1st to 10thNight
33%
720
11%
2156
7%
720
39%
720
11%
1732
October11th to 20thNight
27%
720
10%
2160
5%
720
34%
720
8%
1803
October21st to endNight
22%
792
7%
2572
4%
792
27%
792
8%
2138
November1st to 10thNight
26%
740
9%
2407
6%
740
32%
740
9%
1937
November11th to 20thNight
20%
760
11%
2603
7%
760
26%
760
8%
2143
November21st to endNight
18%
760
6%
2660
4%
760
22%
760
4%
2310
December1st to 10thNight
14%
760
3%
2660
1%
760
16%
760
3%
2389
December11th to 20thNight
14%
760
8%
3242
3%
759
20%
759
4%
2707
December21st to endNight
11%
828
4%
4844
2%
817
15%
817
2%
4108

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
19%10%47%6%3445%6%32%
74737
Night
19%11%47%5%34446%32%
74976
TransparencyDay
35%38%8%12%7%1
74442
Night
36%38%7%12%6%1
74805
SeeingDay
26%15%30%19%8%2
13394
Night
25%12%29%25%9%1
22542

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
19%20%7%9%8%3434419%
1517
11th to 20thDay
21%17%7%7%6%34346%23%
1454
21st to endDay
14%14%6%9%6%37%6%5%5%26%
1588
February1st to 10thDay
15%17%5%12%7%34346%24%
1620
11th to 20thDay
14%16%5%10%7%44446%26%
1620
21st to endDay
20%15%6%8%7%45%44425%
1480
March1st to 10thDay
16%14%5%9%7%35%445%28%
1797
11th to 20thDay
16%13%5%7%7%345%45%30%
1916
21st to endDay
21%9%46%5%34345%35%
2335
April1st to 10thDay
22%13%46%5%34346%32%
2160
11th to 20thDay
22%9%36%444445%35%
2134
21st to endDay
24%10%36%5%3445%5%30%
2288
May1st to 10thDay
22%8%37%5%35%445%33%
2520
11th to 20thDay
20%8%35%5%345%5%6%37%
2478
21st to endDay
19%7%36%5%35%5%5%7%37%
2725
June1st to 10thDay
24%7%36%6%35%5%6%7%29%
2520
11th to 20thDay
16%6%35%5%45%6%6%7%37%
2520
21st to endDay
22%6%36%7%446%6%8%28%
2520
July1st to 10thDay
14%5%36%5%36%6%6%8%39%
2520
11th to 20thDay
16%6%35%6%45%6%7%8%34%
2520
21st to endDay
13%6%27%6%45%6%7%8%35%
2744
August1st to 10thDay
15%6%35%6%45%6%6%7%36%
2506
11th to 20thDay
14%6%36%5%45%5%5%8%38%
2272
21st to endDay
15%6%36%5%35%45%8%40%
2376
September1st to 10thDay
17%6%245%345%6%7%42%
2160
11th to 20thDay
16%425%42446%6%47%
2122
21st to endDay
21%6%244345%5%7%40%
1980
October1st to 10thDay
24%8%26%5%34447%35%
1800
11th to 20thDay
27%9%47%6%435%46%26%
1800
21st to endDay
27%11%47%5%34446%25%
1782
November1st to 10thDay
18%11%35%5%4445%7%33%
1671
11th to 20thDay
22%11%5%8%6%445%5%6%24%
1574
21st to endDay
23%14%5%8%6%34436%24%
1520
December1st to 10thDay
25%17%6%8%6%34445%18%
1520
11th to 20thDay
22%15%5%9%5%24445%24%
1906
21st to endDay
26%21%5%7%6%2433319%
2772
January1st to 10thNight
20%18%7%10%6%44445%18%
2649
11th to 20thNight
19%18%5%9%6%34345%23%
2546
21st to endNight
13%14%6%9%7%45%446%29%
2763
February1st to 10thNight
15%15%6%11%7%45%45%5%24%
2340
11th to 20thNight
15%12%6%11%8%44445%28%
2225
21st to endNight
17%12%6%9%5%35%446%29%
1776
March1st to 10thNight
17%13%6%8%6%35%445%29%
2150
11th to 20thNight
19%13%5%6%5%34446%32%
2038
21st to endNight
18%9%36%5%3444440%
2021
April1st to 10thNight
24%9%36%5%34445%33%
1800
11th to 20thNight
21%7%46%6%24346%36%
1775
21st to endNight
21%10%46%5%25%445%35%
1689
May1st to 10thNight
21%8%36%5%35%45%5%35%
1440
11th to 20thNight
20%6%26%434445%42%
1415
21st to endNight
18%6%345%345%5%6%42%
1550
June1st to 10thNight
20%6%36%5%35%5%7%9%31%
1440
11th to 20thNight
17%5%47%4346%5%6%40%
1440
21st to endNight
20%6%26%5%35%5%6%7%36%
1440
July1st to 10thNight
12%6%25%435%5%5%7%46%
1440
11th to 20thNight
13%5%35%4445%7%9%41%
1440
21st to endNight
13%5%35%5%35%5%5%8%42%
1574
August1st to 10thNight
12%5%35%5%345%7%9%41%
1432
11th to 20thNight
12%6%25%5%3447%6%45%
1606
21st to endNight
14%5%25%5%3446%7%44%
1980
September1st to 10thNight
14%5%26%5%3445%7%44%
1800
11th to 20thNight
18%41442346%6%48%
1837
21st to endNight
19%6%24434347%44%
1980
October1st to 10thNight
21%7%35%5%3445%6%37%
2156
11th to 20thNight
24%8%36%6%24446%32%
2160
21st to endNight
26%10%38%6%34435%30%
2572
November1st to 10thNight
22%10%46%5%3445%6%33%
2407
11th to 20thNight
20%11%47%7%35%445%31%
2603
21st to endNight
23%14%5%7%6%34445%24%
2660
December1st to 10thNight
22%17%7%9%6%34445%19%
2660
11th to 20thNight
24%15%5%8%5%34435%25%
3288
21st to endNight
28%18%49%5%2343320%
4884

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
43%41%5%9%3
1518
11th to 20thDay
39%42%5%8%5%1
1454
21st to endDay
39%37%7%9%8%
1588
February1st to 10thDay
40%37%6%12%5%1
1620
11th to 20thDay
40%38%7%9%41
1629
21st to endDay
42%36%5%11%5%
1480
March1st to 10thDay
39%38%6%11%5%1
1800
11th to 20thDay
37%37%10%11%5%
1916
21st to endDay
33%37%7%11%9%2
2335
April1st to 10thDay
37%36%6%13%7%2
2160
11th to 20thDay
34%36%6%13%10%1
2134
21st to endDay
37%37%5%10%8%3
2288
May1st to 10thDay
34%37%5%11%10%3
2520
11th to 20thDay
32%38%6%13%9%3
2482
21st to endDay
28%38%8%12%12%2
2725
June1st to 10thDay
36%39%8%11%7%
2520
11th to 20thDay
29%39%7%15%8%2
2520
21st to endDay
36%40%9%9%5%1
2520
July1st to 10thDay
27%41%8%17%6%
2450
11th to 20thDay
29%40%9%14%7%
2445
21st to endDay
28%42%9%14%7%
2591
August1st to 10thDay
31%39%9%16%5%
2492
11th to 20thDay
26%39%11%17%6%
2272
21st to endDay
28%39%9%14%9%1
2376
September1st to 10thDay
27%38%8%19%8%
2160
11th to 20thDay
26%38%9%18%9%
2122
21st to endDay
31%38%10%17%5%
1980
October1st to 10thDay
34%37%7%15%6%
1800
11th to 20thDay
40%38%8%10%5%
1800
21st to endDay
39%39%8%9%5%1
1782
November1st to 10thDay
27%42%9%16%5%
1671
11th to 20thDay
38%41%9%6%7%
1574
21st to endDay
40%41%8%9%2
1520
December1st to 10thDay
46%41%6%42
1520
11th to 20thDay
44%33%11%9%2
1906
21st to endDay
56%26%5%10%3
2772
January1st to 10thNight
44%41%6%7%2
2649
11th to 20thNight
42%42%47%4
2546
21st to endNight
38%38%7%10%7%1
2763
February1st to 10thNight
41%37%6%11%5%1
2340
11th to 20thNight
40%38%8%11%4
2227
21st to endNight
40%36%7%12%5%1
1776
March1st to 10thNight
39%37%6%12%5%1
2160
11th to 20thNight
38%37%8%11%41
2039
21st to endNight
32%36%6%13%10%3
2021
April1st to 10thNight
36%37%7%11%8%2
1800
11th to 20thNight
32%36%6%14%10%1
1775
21st to endNight
34%37%6%12%9%2
1689
May1st to 10thNight
33%37%5%10%11%4
1440
11th to 20thNight
27%37%6%14%13%3
1416
21st to endNight
27%39%7%12%13%2
1551
June1st to 10thNight
33%39%9%14%5%
1440
11th to 20thNight
30%38%8%14%9%2
1440
21st to endNight
33%40%8%10%9%
1440
July1st to 10thNight
25%40%9%19%7%
1400
11th to 20thNight
27%40%9%16%8%
1392
21st to endNight
27%40%10%15%9%
1486
August1st to 10thNight
28%39%11%16%6%
1422
11th to 20thNight
23%38%12%19%8%
1606
21st to endNight
27%39%11%15%8%
1980
September1st to 10thNight
27%38%8%16%9%1
1800
11th to 20thNight
25%37%8%22%7%1
1837
21st to endNight
28%38%9%18%7%
1980
October1st to 10thNight
32%38%7%14%8%
2156
11th to 20thNight
37%38%7%13%5%
2160
21st to endNight
38%38%9%10%5%1
2572
November1st to 10thNight
31%41%9%14%5%
2407
11th to 20thNight
34%40%8%10%6%1
2603
21st to endNight
40%42%6%10%2
2660
December1st to 10thNight
45%41%6%7%2
2660
11th to 20thNight
44%33%6%13%3
3288
21st to endNight
55%26%6%10%2
4884

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
31%17%32%16%4
180
11th to 20thDay
30%18%37%8%7%
164
21st to endDay
25%17%35%18%41
178
February1st to 10thDay
35%27%33%5%
240
11th to 20thDay
28%28%35%9%
287
21st to endDay
33%20%29%16%2
346
March1st to 10thDay
30%17%33%18%2
420
11th to 20thDay
29%20%33%13%41
420
21st to endDay
32%18%26%17%6%2
462
April1st to 10thDay
30%19%29%15%6%1
420
11th to 20thDay
33%17%23%16%8%1
412
21st to endDay
33%18%32%10%6%1
420
May1st to 10thDay
28%17%33%16%5%2
423
11th to 20thDay
22%20%31%20%6%1
447
21st to endDay
23%16%34%20%6%1
485
June1st to 10thDay
27%11%34%19%8%1
450
11th to 20thDay
18%15%34%21%10%3
450
21st to endDay
25%11%32%20%10%2
450
July1st to 10thDay
16%8%34%26%13%4
445
11th to 20thDay
16%10%35%25%12%2
444
21st to endDay
17%9%32%29%11%3
488
August1st to 10thDay
17%7%27%33%12%3
446
11th to 20thDay
19%5%25%31%14%6%
439
21st to endDay
18%13%25%23%15%6%
495
September1st to 10thDay
20%10%29%23%14%5%
450
11th to 20thDay
17%8%28%20%17%9%
450
21st to endDay
22%13%26%22%14%5%
450
October1st to 10thDay
27%14%23%22%12%3
450
11th to 20thDay
30%17%26%19%7%1
450
21st to endDay
34%13%29%19%4
396
November1st to 10thDay
32%13%28%21%5%1
365
11th to 20thDay
28%20%35%10%6%
234
21st to endDay
32%21%29%15%3
180
December1st to 10thDay
35%11%36%15%31
180
11th to 20thDay
31%25%33%9%3
180
21st to endDay
35%19%30%12%31
198
January1st to 10thNight
30%13%34%20%4
760
11th to 20thNight
29%16%29%20%6%1
728
21st to endNight
19%16%36%23%6%1
792
February1st to 10thNight
23%17%33%22%4
720
11th to 20thNight
23%18%33%21%4
703
21st to endNight
25%16%32%23%31
592
March1st to 10thNight
25%15%32%23%5%
720
11th to 20thNight
27%18%30%20%5%
720
21st to endNight
24%14%30%25%7%
792
April1st to 10thNight
29%14%29%24%4
720
11th to 20thNight
25%14%32%22%7%
711
21st to endNight
28%13%30%21%7%
609
May1st to 10thNight
24%11%29%26%8%2
360
11th to 20thNight
23%10%29%30%8%1
354
21st to endNight
21%6%34%28%10%1
389
June1st to 10thNight
21%6%29%32%10%
360
11th to 20thNight
20%7%26%34%12%1
360
21st to endNight
21%426%32%15%1
360
July1st to 10thNight
12%7%27%36%18%
350
11th to 20thNight
14%321%43%18%1
348
21st to endNight
15%325%38%18%1
394
August1st to 10thNight
14%417%44%21%1
358
11th to 20thNight
15%319%35%25%3
542
21st to endNight
17%423%34%19%2
792
September1st to 10thNight
17%6%27%33%15%1
720
11th to 20thNight
22%5%20%30%21%3
720
21st to endNight
23%8%22%29%16%3
720
October1st to 10thNight
25%8%26%28%12%
720
11th to 20thNight
28%10%28%27%7%1
720
21st to endNight
30%11%28%25%5%
792
November1st to 10thNight
28%11%28%24%8%1
740
11th to 20thNight
26%15%31%18%9%1
760
21st to endNight
31%14%29%18%7%
760
December1st to 10thNight
31%15%31%19%4
760
11th to 20thNight
30%17%29%18%5%1
760
21st to endNight
37%14%28%17%4
836
Page generated at 2024-01-09 16:24:26. Version ac07

Copyright 2024 Attilla Danko


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