Mont-Laurier
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mont-Laurier clear sky chart from 2005-11-05 to 2018-03-21.

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
29%
15303
12%
49251
8%
15273
34%
15273
15%
36046

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
17%
780
7%
2716
4%
776
21%
776
7%
2238
January16th to endNight
21%
832
9%
2902
5%
832
27%
832
10%
2244
February1st to 15thNight
19%
763
10%
2482
5%
761
26%
761
10%
1956
February16th to endNight
21%
683
11%
2114
6%
683
28%
683
11%
1636
March1st to 15thNight
21%
780
12%
2291
7%
780
27%
780
12%
1815
March16th to endNight
30%
792
21%
2090
9%
792
38%
792
23%
1463
April1st to 15thNight
27%
718
16%
1796
7%
718
31%
718
20%
1343
April16th to endNight
31%
605
17%
1685
9%
605
37%
605
22%
1170
May1st to 15thNight
30%
360
16%
1440
16%
360
38%
360
16%
955
May16th to endNight
31%
374
12%
1497
11%
374
42%
374
16%
997
June1st to 15thNight
31%
360
7%
1440
6%
360
38%
360
15%
978
June16th to endNight
45%
360
7%
1440
10%
360
47%
360
20%
902
July1st to 15thNight
49%
340
10%
1360
14%
340
54%
340
23%
781
July16th to endNight
54%
376
12%
1418
17%
354
55%
354
24%
832
August1st to 15thNight
50%
401
14%
1472
14%
399
54%
399
22%
939
August16th to endNight
51%
702
19%
1848
9%
702
56%
702
35%
1151
September1st to 15thNight
41%
720
14%
1800
6%
720
43%
720
28%
1248
September16th to endNight
43%
717
19%
1956
13%
717
47%
717
29%
1285
October1st to 15thNight
29%
720
16%
2160
10%
720
37%
720
19%
1520
October16th to endNight
22%
768
10%
2424
6%
768
28%
768
12%
1879
November1st to 15thNight
24%
760
15%
2548
11%
760
32%
760
13%
1889
November16th to endNight
18%
780
9%
2730
6%
780
23%
780
8%
2188
December1st to 15thNight
15%
780
7%
2730
3%
780
20%
780
6%
2259
December16th to endNight
15%
832
10%
2912
5%
832
22%
832
7%
2378

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%34446%28%
49606
Night
18%11%47%6%34445%28%
49420
TransparencyDay
57%310%19%8%
49293
Night
57%310%19%8%
49251
SeeingDay
27%10%28%20%10%3
5982
Night
26%9%26%25%10%1
15305

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
21%18%8%12%6%2422415%
1552
16th to endDay
13%16%8%10%6%35%45%6%20%
1674
February1st to 15thDay
9%18%8%12%10%5%433417%
1710
16th to endDay
17%18%6%9%6%3323423%
1644
March1st to 15thDay
16%16%6%9%6%3444424%
1985
16th to endDay
14%9%46%5%33446%36%
2261
April1st to 15thDay
23%13%45%5%33335%29%
2152
16th to endDay
21%9%35%434345%34%
2283
May1st to 15thDay
24%9%35%5%24446%29%
2511
16th to endDay
21%8%35%5%34446%31%
2618
June1st to 15thDay
23%7%36%7%36%45%6%26%
2520
16th to endDay
18%5%26%6%36%5%6%7%29%
2520
July1st to 15thDay
18%6%24435%5%5%8%33%
2520
16th to endDay
14%6%37%6%35%5%6%8%32%
2654
August1st to 15thDay
16%7%36%6%36%5%6%7%28%
2476
16th to endDay
14%6%26%6%35%5%6%7%36%
2341
September1st to 15thDay
20%7%26%423346%36%
2160
16th to endDay
20%6%24413446%41%
2003
October1st to 15thDay
25%9%26%5%33437%29%
1800
16th to endDay
29%13%48%5%3443419%
1800
November1st to 15thDay
19%11%47%5%3445%6%27%
1638
16th to endDay
26%16%6%8%6%1322420%
1560
December1st to 15thDay
22%20%7%9%8%3243413%
1560
16th to endDay
21%17%7%10%7%3433417%
1664
January1st to 15thNight
21%17%6%10%7%3444415%
2716
16th to endNight
14%15%7%9%7%35%445%20%
2902
February1st to 15thNight
10%14%7%12%10%46%44421%
2480
16th to endNight
15%13%6%10%7%35%44422%
2114
March1st to 15thNight
19%14%5%8%6%36%44421%
2278
16th to endNight
14%8%5%6%6%3334439%
2090
April1st to 15thNight
24%9%445%3424432%
1796
16th to endNight
21%7%25%424345%38%
1685
May1st to 15thNight
21%10%36%32435%5%33%
1440
16th to endNight
18%8%25%5%3445%6%33%
1495
June1st to 15thNight
19%8%35%6%3447%7%29%
1440
16th to endNight
16%5%346%3445%8%36%
1440
July1st to 15thNight
12%4245%346%5%7%41%
1440
16th to endNight
10%435%5%246%6%8%41%
1514
August1st to 15thNight
12%6%35%5%45%5%6%8%36%
1482
16th to endNight
13%42432346%8%45%
1848
September1st to 15thNight
19%7%25%5%24445%39%
1800
16th to endNight
18%5%14423436%44%
1956
October1st to 15thNight
23%8%25%5%33345%34%
2160
16th to endNight
28%11%36%5%24445%21%
2424
November1st to 15thNight
21%12%47%5%3434427%
2548
16th to endNight
24%16%6%8%5%2333419%
2730
December1st to 15thNight
22%19%8%8%6%3433415%
2730
16th to endNight
21%18%6%9%6%3444416%
2912

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
74%15%11%5%
1553
16th to endDay
64%38%15%7%
1674
February1st to 15thDay
69%17%13%6%
1712
16th to endDay
66%16%16%8%
1644
March1st to 15thDay
63%28%15%9%1
1995
16th to endDay
49%38%19%15%3
2261
April1st to 15thDay
58%27%18%10%2
2152
16th to endDay
53%27%20%12%3
2283
May1st to 15thDay
56%26%20%12%1
2511
16th to endDay
54%310%19%11%1
2622
June1st to 15thDay
58%39%20%9%
2520
16th to endDay
50%413%21%9%
2520
July1st to 15thDay
45%414%24%10%
2371
16th to endDay
50%316%20%8%
2487
August1st to 15thDay
52%5%14%21%5%
2462
16th to endDay
44%416%25%8%
2341
September1st to 15thDay
48%213%22%11%
2160
16th to endDay
43%313%30%8%
2003
October1st to 15thDay
56%211%20%8%
1800
16th to endDay
69%310%13%3
1800
November1st to 15thDay
57%314%16%7%
1638
16th to endDay
70%29%12%5%
1560
December1st to 15thDay
74%28%12%2
1560
16th to endDay
72%26%12%6%
1664
January1st to 15thNight
73%28%11%3
2716
16th to endNight
65%27%16%6%
2902
February1st to 15thNight
67%28%16%5%
2482
16th to endNight
64%27%16%8%
2114
March1st to 15thNight
65%36%16%7%
2291
16th to endNight
48%28%20%16%2
2090
April1st to 15thNight
56%15%20%13%2
1796
16th to endNight
49%28%21%15%2
1685
May1st to 15thNight
52%26%20%14%3
1440
16th to endNight
51%310%21%11%1
1497
June1st to 15thNight
52%312%20%9%
1440
16th to endNight
45%414%22%12%
1440
July1st to 15thNight
39%317%24%13%
1360
16th to endNight
39%5%17%28%9%
1418
August1st to 15thNight
43%5%17%25%7%
1472
16th to endNight
35%319%32%7%
1848
September1st to 15thNight
46%214%25%10%
1800
16th to endNight
42%314%32%7%
1956
October1st to 15thNight
52%211%22%10%
2160
16th to endNight
63%311%17%4
2424
November1st to 15thNight
59%311%16%7%
2548
16th to endNight
68%39%14%3
2730
December1st to 15thNight
73%38%11%3
2730
16th to endNight
71%27%12%6%
2912

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
25%17%35%14%6%
90
16th to endDay
33%13%31%17%4
98
February1st to 15thDay
20%20%46%9%2
135
16th to endDay
37%16%25%16%4
225
March1st to 15thDay
31%13%31%15%6%
330
16th to endDay
23%17%29%18%7%3
311
April1st to 15thDay
31%13%24%21%8%
270
16th to endDay
28%12%28%16%12%1
270
May1st to 15thDay
35%8%26%18%7%3
288
16th to endDay
29%11%30%16%10%2
331
June1st to 15thDay
33%7%30%19%7%1
315
16th to endDay
18%7%33%26%10%2
315
July1st to 15thDay
19%5%34%26%10%3
305
16th to endDay
19%5%23%32%15%3
326
August1st to 15thDay
24%323%27%16%6%
313
16th to endDay
18%6%29%22%14%8%
332
September1st to 15thDay
26%6%21%20%14%9%
315
16th to endDay
22%8%21%23%15%9%
314
October1st to 15thDay
30%12%24%18%11%2
315
16th to endDay
39%9%25%16%8%
306
November1st to 15thDay
26%12%29%21%8%
202
16th to endDay
35%23%27%8%31
90
December1st to 15thDay
30%16%34%16%2
90
16th to endDay
31%20%37%8%2
96
January1st to 15thNight
32%10%28%22%5%
780
16th to endNight
22%11%31%25%8%
832
February1st to 15thNight
18%13%35%24%7%1
764
16th to endNight
23%13%32%24%5%
683
March1st to 15thNight
29%12%27%24%4
780
16th to endNight
20%14%29%25%9%1
792
April1st to 15thNight
31%11%23%26%6%
718
16th to endNight
28%11%25%24%10%
605
May1st to 15thNight
27%5%29%26%10%
360
16th to endNight
23%8%29%27%10%
375
June1st to 15thNight
26%6%27%29%9%
360
16th to endNight
18%5%22%38%14%
360
July1st to 15thNight
14%326%36%19%
340
16th to endNight
11%421%43%16%2
376
August1st to 15thNight
19%218%31%24%3
401
16th to endNight
16%5%21%32%22%2
702
September1st to 15thNight
24%423%28%17%1
720
16th to endNight
22%5%23%26%18%2
717
October1st to 15thNight
29%9%25%24%10%1
720
16th to endNight
38%8%24%21%6%
768
November1st to 15thNight
29%11%25%21%9%1
760
16th to endNight
36%14%24%18%6%1
780
December1st to 15thNight
33%13%27%19%4
780
16th to endNight
32%11%28%20%41
832
Page generated at 2018-03-22 11:34:23. Version ac04

Copyright 2018 A. Danko


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