La Tuque
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Tuque clear sky chart from 2005-11-06 to 2024-01-16.

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%
22586
10%
74968
6%
22542
31%
22542
12%
57154

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
14%
760
6%
2649
3%
757
19%
757
5%
2287
January11th to 20thNight
16%
744
8%
2602
4%
744
21%
744
7%
2094
January21st to endNight
24%
792
12%
2772
7%
792
31%
792
11%
2074
February1st to 10thNight
21%
720
10%
2476
6%
720
28%
720
10%
1934
February11th to 20thNight
15%
703
8%
2179
3%
700
22%
700
9%
1759
February21st to endNight
22%
592
13%
1776
8%
592
30%
592
12%
1369
March1st to 10thNight
20%
720
12%
2160
8%
720
27%
720
12%
1687
March11th to 20thNight
23%
720
12%
2112
5%
720
30%
720
12%
1637
March21st to endNight
24%
792
17%
1980
5%
792
31%
792
16%
1520
April1st to 10thNight
22%
720
10%
1800
4%
720
24%
720
13%
1447
April11th to 20thNight
25%
672
14%
1736
6%
672
30%
672
18%
1286
April21st to endNight
21%
540
15%
1620
7%
540
29%
540
15%
1175
May1st to 10thNight
26%
398
14%
1478
9%
398
36%
398
14%
1025
May11th to 20thNight
30%
354
17%
1416
14%
354
44%
354
15%
953
May21st to endNight
25%
389
11%
1551
8%
388
37%
388
14%
1055
June1st to 10thNight
30%
360
7%
1346
5%
360
35%
360
13%
948
June11th to 20thNight
36%
360
9%
1260
7%
360
41%
360
17%
849
June21st to endNight
38%
360
7%
1333
7%
360
41%
360
15%
953
July1st to 10thNight
40%
350
6%
1400
8%
350
44%
350
15%
948
July11th to 20thNight
44%
348
10%
1392
16%
348
48%
348
18%
907
July21st to endNight
48%
394
9%
1486
12%
372
49%
372
16%
1001
August1st to 10thNight
48%
358
12%
1422
13%
356
53%
356
17%
936
August11th to 20thNight
43%
445
12%
1509
9%
445
47%
445
18%
1045
August21st to endNight
39%
766
15%
1954
8%
766
41%
766
23%
1395
September1st to 10thNight
40%
720
13%
1800
5%
720
43%
720
26%
1271
September11th to 20thNight
41%
720
14%
1903
7%
720
44%
720
24%
1343
September21st to endNight
34%
720
16%
1980
11%
720
38%
720
21%
1405
October1st to 10thNight
33%
720
16%
2065
11%
720
40%
720
19%
1465
October11th to 20thNight
24%
720
9%
2263
4%
720
28%
720
12%
1773
October21st to endNight
19%
792
9%
2574
4%
792
25%
792
10%
2065
November1st to 10thNight
21%
740
11%
2407
6%
740
28%
740
11%
1865
November11th to 20thNight
22%
760
12%
2569
8%
760
27%
760
9%
2030
November21st to endNight
18%
785
6%
2713
4%
785
21%
785
6%
2283
December1st to 10thNight
17%
850
6%
2850
3%
850
21%
850
6%
2413
December11th to 20thNight
16%
850
8%
3487
4%
848
20%
848
6%
2854
December21st to endNight
14%
852
5%
4948
3%
841
19%
841
3%
4103

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%11%5%8%7%45%45%6%26%
74561
Night
19%12%5%9%7%45%45%5%26%
75215
TransparencyDay
59%6%10%16%8%1
74266
Night
60%6%11%16%7%1
75045
SeeingDay
26%17%30%18%8%2
13736
Night
26%13%28%25%8%1
22597

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
16%17%7%15%10%45%5%4313%
1517
11th to 20thDay
15%17%7%10%8%5%5%5%5%5%18%
1480
21st to endDay
12%12%7%10%10%5%5%6%5%6%22%
1584
February1st to 10thDay
9%15%6%13%11%7%6%5%45%18%
1480
11th to 20thDay
13%18%7%11%8%46%45%419%
1667
21st to endDay
14%16%7%10%8%36%445%23%
1480
March1st to 10thDay
14%14%7%11%8%35%44426%
1797
11th to 20thDay
17%14%6%9%7%35%445%26%
1844
21st to endDay
17%13%5%9%7%35%445%27%
2376
April1st to 10thDay
22%14%5%9%6%3444424%
2160
11th to 20thDay
22%11%46%5%34346%33%
2173
21st to endDay
22%12%46%6%33446%29%
2340
May1st to 10thDay
22%10%37%6%34446%32%
2497
11th to 20thDay
20%8%36%6%45%45%7%33%
2478
21st to endDay
20%8%47%7%35%5%5%7%30%
2725
June1st to 10thDay
23%8%47%6%45%5%6%6%27%
2610
11th to 20thDay
20%8%36%5%35%5%5%7%31%
2700
21st to endDay
24%8%46%6%46%5%6%7%25%
2621
July1st to 10thDay
17%7%38%7%46%6%6%8%28%
2520
11th to 20thDay
16%7%48%7%46%6%6%8%28%
2520
21st to endDay
15%7%48%7%46%6%6%7%29%
2744
August1st to 10thDay
17%8%49%7%46%6%7%8%24%
2506
11th to 20thDay
18%7%37%6%5%5%6%6%9%29%
2374
21st to endDay
17%7%47%7%46%6%6%7%30%
2399
September1st to 10thDay
19%6%36%6%445%5%6%35%
2160
11th to 20thDay
19%8%37%5%345%5%6%36%
2057
21st to endDay
25%8%35%5%44446%32%
1980
October1st to 10thDay
24%10%47%6%35%5%46%27%
1892
11th to 20thDay
28%13%48%7%45%346%18%
1697
21st to endDay
29%16%5%6%433436%21%
1782
November1st to 10thDay
21%14%5%9%7%3444425%
1671
11th to 20thDay
21%18%6%11%7%3434420%
1607
21st to endDay
21%19%8%11%8%43445%14%
1463
December1st to 10thDay
24%17%6%12%7%45%33415%
1330
11th to 20thDay
22%17%7%8%8%3433421%
1668
21st to endDay
22%19%7%10%11%3444412%
2662
January1st to 10thNight
18%18%8%13%9%46%44412%
2649
11th to 20thNight
17%16%6%12%9%45%45%6%16%
2602
21st to endNight
10%13%6%10%8%5%7%6%6%7%22%
2772
February1st to 10thNight
11%13%7%10%11%5%5%5%6%6%21%
2476
11th to 20thNight
11%16%7%13%9%47%44321%
2177
21st to endNight
12%15%7%11%7%5%5%5%5%5%24%
1776
March1st to 10thNight
15%13%6%11%7%46%435%25%
2150
11th to 20thNight
18%14%48%7%46%5%46%25%
2111
21st to endNight
16%11%5%9%7%45%35%430%
1980
April1st to 10thNight
21%16%5%9%7%34445%23%
1800
11th to 20thNight
21%9%47%6%34446%33%
1736
21st to endNight
22%12%46%5%23346%33%
1620
May1st to 10thNight
22%9%36%6%35%445%34%
1478
11th to 20thNight
21%9%37%5%24346%35%
1415
21st to endNight
23%7%37%6%33445%36%
1550
June1st to 10thNight
20%8%46%6%36%5%5%6%31%
1346
11th to 20thNight
19%7%446%35%6%5%8%34%
1260
21st to endNight
21%8%45%6%45%5%7%8%28%
1333
July1st to 10thNight
17%5%38%6%45%6%6%9%30%
1440
11th to 20thNight
13%6%37%6%45%6%6%8%35%
1440
21st to endNight
16%7%36%6%45%5%7%7%35%
1574
August1st to 10thNight
14%6%26%5%45%5%8%9%35%
1432
11th to 20thNight
15%8%36%7%35%5%7%8%31%
1509
21st to endNight
19%6%36%5%345%5%6%37%
1954
September1st to 10thNight
20%6%27%5%34447%40%
1800
11th to 20thNight
20%6%46%5%35%35%6%38%
1903
21st to endNight
21%7%36%5%24445%39%
1980
October1st to 10thNight
21%10%35%5%3345%6%35%
2065
11th to 20thNight
28%12%47%6%3445%5%23%
2263
21st to endNight
26%13%48%6%35%44422%
2574
November1st to 10thNight
20%16%5%9%6%34446%24%
2407
11th to 20thNight
22%12%5%8%8%45%5%5%422%
2569
21st to endNight
24%17%6%10%8%4445%415%
2713
December1st to 10thNight
21%18%8%11%8%35%43415%
2850
11th to 20thNight
20%16%7%11%7%45%44418%
3531
21st to endNight
21%21%7%11%8%3433315%
4980

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
75%48%9%4
1518
11th to 20thDay
68%5%8%14%6%
1480
21st to endDay
61%6%7%15%11%1
1584
February1st to 10thDay
69%5%6%12%7%1
1480
11th to 20thDay
68%49%10%9%1
1676
21st to endDay
65%47%15%7%2
1480
March1st to 10thDay
62%47%15%10%2
1800
11th to 20thDay
62%48%15%10%1
1844
21st to endDay
59%47%16%11%2
2376
April1st to 10thDay
65%5%9%11%9%2
2160
11th to 20thDay
54%48%18%12%3
2173
21st to endDay
58%49%15%13%2
2340
May1st to 10thDay
54%49%17%14%3
2497
11th to 20thDay
50%6%9%18%14%2
2482
21st to endDay
54%7%9%16%13%2
2725
June1st to 10thDay
56%7%9%16%10%2
2610
11th to 20thDay
50%7%11%19%10%2
2700
21st to endDay
57%8%11%13%11%
2621
July1st to 10thDay
50%9%13%21%7%
2450
11th to 20thDay
52%9%13%20%6%
2445
21st to endDay
52%9%15%18%6%
2591
August1st to 10thDay
57%9%14%17%3
2492
11th to 20thDay
50%9%16%18%7%
2374
21st to endDay
51%9%12%21%7%
2399
September1st to 10thDay
48%7%13%21%9%1
2160
11th to 20thDay
48%7%17%19%9%
2057
21st to endDay
54%6%14%19%7%
1980
October1st to 10thDay
58%6%10%18%8%
1892
11th to 20thDay
69%5%10%14%2
1697
21st to endDay
66%5%11%13%5%
1782
November1st to 10thDay
63%6%11%14%6%1
1671
11th to 20thDay
69%410%12%4
1607
21st to endDay
73%5%11%9%2
1463
December1st to 10thDay
74%5%6%12%3
1330
11th to 20thDay
70%37%15%5%
1668
21st to endDay
76%47%10%3
2662
January1st to 10thNight
77%47%8%3
2649
11th to 20thNight
69%49%12%5%1
2602
21st to endNight
59%6%9%15%10%
2772
February1st to 10thNight
63%6%9%14%8%1
2476
11th to 20thNight
68%48%12%7%1
2179
21st to endNight
61%5%8%16%9%
1776
March1st to 10thNight
62%47%16%9%1
2160
11th to 20thNight
61%5%9%13%11%1
2112
21st to endNight
58%47%19%9%3
1980
April1st to 10thNight
64%410%12%9%2
1800
11th to 20thNight
52%5%8%20%12%2
1736
21st to endNight
54%5%9%19%12%2
1620
May1st to 10thNight
53%5%10%15%14%3
1478
11th to 20thNight
51%5%9%20%13%2
1416
21st to endNight
52%5%8%20%13%2
1551
June1st to 10thNight
52%8%10%20%9%1
1346
11th to 20thNight
48%7%13%19%11%3
1260
21st to endNight
52%8%13%16%11%
1333
July1st to 10thNight
47%10%17%19%6%
1400
11th to 20thNight
44%9%16%23%8%
1392
21st to endNight
46%10%14%23%7%
1486
August1st to 10thNight
43%11%19%24%4
1422
11th to 20thNight
46%10%20%18%5%
1509
21st to endNight
47%6%15%26%6%
1954
September1st to 10thNight
44%7%14%25%9%1
1800
11th to 20thNight
47%6%16%25%6%1
1903
21st to endNight
49%5%13%26%7%
1980
October1st to 10thNight
51%5%14%20%10%1
2065
11th to 20thNight
61%7%13%15%4
2263
21st to endNight
65%6%10%14%5%
2574
November1st to 10thNight
63%5%12%15%5%
2407
11th to 20thNight
64%7%10%13%6%
2569
21st to endNight
72%6%9%11%2
2713
December1st to 10thNight
74%410%10%2
2850
11th to 20thNight
71%46%13%5%
3532
21st to endNight
75%48%10%3
4980

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
23%18%43%12%5%
180
11th to 20thDay
26%15%39%13%6%
170
21st to endDay
20%15%36%20%7%1
176
February1st to 10thDay
22%30%34%12%11
178
11th to 20thDay
27%26%31%13%2
334
21st to endDay
25%26%30%14%5%
346
March1st to 10thDay
23%20%33%17%5%
420
11th to 20thDay
27%22%28%16%6%1
420
21st to endDay
26%24%27%15%6%2
462
April1st to 10thDay
30%20%27%16%6%1
420
11th to 20thDay
35%16%24%15%8%2
412
21st to endDay
31%19%32%12%41
420
May1st to 10thDay
31%17%31%15%6%1
423
11th to 20thDay
25%17%32%18%6%1
447
21st to endDay
26%22%30%16%6%1
485
June1st to 10thDay
27%18%30%18%7%1
540
11th to 20thDay
25%15%27%21%10%1
630
21st to endDay
26%10%30%25%9%1
551
July1st to 10thDay
20%12%34%24%8%2
445
11th to 20thDay
17%12%36%25%8%2
444
21st to endDay
18%13%30%26%11%2
488
August1st to 10thDay
20%12%28%26%11%3
446
11th to 20thDay
19%8%30%26%12%5%
439
21st to endDay
22%17%26%17%12%5%
495
September1st to 10thDay
22%14%30%19%10%5%
450
11th to 20thDay
20%14%28%23%10%4
450
21st to endDay
26%15%26%16%11%5%
450
October1st to 10thDay
27%19%22%18%12%2
450
11th to 20thDay
33%19%26%12%9%2
399
21st to endDay
41%13%26%15%6%1
396
November1st to 10thDay
33%19%27%14%5%2
365
11th to 20thDay
30%19%31%15%4
267
21st to endDay
32%26%28%13%2
180
December1st to 10thDay
33%13%33%16%41
180
11th to 20thDay
30%21%36%9%31
180
21st to endDay
36%21%25%12%5%2
198
January1st to 10thNight
26%16%32%20%6%1
760
11th to 20thNight
26%16%30%21%7%
744
21st to endNight
18%13%33%26%9%1
792
February1st to 10thNight
18%17%33%23%8%
720
11th to 20thNight
22%16%36%20%5%
703
21st to endNight
22%17%30%26%5%
592
March1st to 10thNight
23%15%33%23%6%
720
11th to 20thNight
27%16%28%22%6%
720
21st to endNight
25%15%29%22%8%1
792
April1st to 10thNight
30%13%27%23%6%1
720
11th to 20thNight
27%12%29%23%8%1
672
21st to endNight
30%16%29%21%4
540
May1st to 10thNight
26%14%29%26%6%
398
11th to 20thNight
27%11%25%29%8%
354
21st to endNight
28%12%30%25%5%
389
June1st to 10thNight
24%8%31%29%8%1
360
11th to 20thNight
20%12%27%32%9%
360
21st to endNight
21%7%26%34%11%1
360
July1st to 10thNight
17%7%27%39%10%
350
11th to 20thNight
15%5%26%38%16%
348
21st to endNight
17%6%23%39%14%1
394
August1st to 10thNight
16%5%23%39%17%1
358
11th to 20thNight
17%7%22%35%18%1
445
21st to endNight
22%10%24%27%14%2
766
September1st to 10thNight
22%7%24%33%13%1
720
11th to 20thNight
23%7%23%31%14%2
720
21st to endNight
25%10%25%25%13%1
720
October1st to 10thNight
25%13%23%29%10%1
720
11th to 20thNight
35%11%24%20%9%1
720
21st to endNight
35%12%27%19%7%
792
November1st to 10thNight
31%13%26%22%5%2
740
11th to 20thNight
29%15%27%20%8%1
760
21st to endNight
33%16%25%21%4
785
December1st to 10thNight
31%15%26%21%7%1
850
11th to 20thNight
28%16%28%21%5%1
850
21st to endNight
33%15%27%20%6%
863
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