Val-d'Or
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Val-d'Or clear sky chart from 2005-11-06 to 2024-01-13.

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
24%
22863
9%
74729
6%
22819
28%
22819
11%
58567

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%
950
5%
2838
3%
946
14%
946
5%
2546
January11th to 20thNight
17%
824
6%
2644
3%
824
20%
824
7%
2229
January21st to endNight
27%
792
8%
2704
6%
792
31%
792
9%
2210
February1st to 10thNight
21%
720
9%
2340
6%
720
25%
720
9%
1882
February11th to 20thNight
17%
703
9%
2275
4%
700
24%
700
10%
1857
February21st to endNight
16%
592
9%
1889
4%
592
22%
592
9%
1518
March1st to 10thNight
23%
720
10%
2084
5%
720
27%
720
12%
1651
March11th to 20thNight
18%
720
12%
1980
5%
720
24%
720
12%
1599
March21st to endNight
26%
792
18%
2123
8%
792
32%
792
18%
1563
April1st to 10thNight
22%
720
12%
1800
5%
720
25%
720
15%
1425
April11th to 20thNight
27%
655
15%
1719
7%
655
31%
655
19%
1272
April21st to endNight
27%
509
15%
1589
7%
509
35%
509
17%
1140
May1st to 10thNight
30%
360
13%
1440
12%
360
38%
360
16%
972
May11th to 20thNight
32%
354
14%
1416
15%
354
42%
354
16%
951
May21st to endNight
29%
389
9%
1551
9%
388
37%
388
16%
1010
June1st to 10thNight
27%
360
7%
1310
5%
360
32%
360
14%
929
June11th to 20thNight
31%
360
9%
1260
6%
360
35%
360
19%
834
June21st to endNight
42%
360
8%
1260
7%
360
44%
360
19%
827
July1st to 10thNight
40%
350
9%
1225
9%
350
43%
350
18%
819
July11th to 20thNight
45%
348
11%
1249
13%
348
49%
348
23%
773
July21st to endNight
47%
394
10%
1486
14%
372
48%
372
17%
995
August1st to 10thNight
43%
400
11%
1464
12%
398
47%
398
17%
995
August11th to 20thNight
45%
534
14%
1598
10%
534
49%
534
24%
1089
August21st to endNight
37%
672
14%
1860
9%
672
40%
672
21%
1324
September1st to 10thNight
34%
720
12%
1800
6%
720
36%
720
23%
1304
September11th to 20thNight
33%
720
13%
1800
5%
720
37%
720
22%
1330
September21st to endNight
33%
720
14%
2074
9%
720
37%
720
20%
1489
October1st to 10thNight
27%
720
14%
2160
10%
720
32%
720
16%
1592
October11th to 20thNight
18%
720
7%
2160
5%
720
22%
720
9%
1790
October21st to endNight
16%
792
7%
2490
3%
792
21%
792
8%
2062
November1st to 10thNight
15%
740
8%
2582
4%
740
21%
740
9%
2077
November11th to 20thNight
12%
760
8%
2660
4%
760
17%
760
6%
2266
November21st to endNight
8%
760
3%
2660
1%
760
10%
760
4%
2385
December1st to 10thNight
12%
760
4%
2660
1%
760
15%
760
4%
2370
December11th to 20thNight
15%
836
5%
3398
4%
835
18%
835
5%
2960
December21st to endNight
13%
1037
4%
5181
3%
1026
15%
1026
2%
4532

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%12%5%8%7%35%5%5%6%25%
74772
Night
18%14%5%9%7%35%445%24%
74954
TransparencyDay
59%7%10%16%7%1
74466
Night
62%6%10%14%7%1
74794
SeeingDay
24%16%32%19%7%2
13874
Night
25%13%30%23%8%1
22871

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%20%10%12%7%5%7%5%5%410%
1328
11th to 20thDay
14%17%8%13%8%46%9%6%412%
1358
21st to endDay
12%15%7%13%11%5%7%6%5%5%15%
1650
February1st to 10thDay
10%14%8%12%12%7%7%45%6%16%
1620
11th to 20thDay
11%19%7%12%9%46%6%45%17%
1573
21st to endDay
12%17%7%12%9%5%45%5%5%21%
1365
March1st to 10thDay
13%15%5%12%8%5%6%5%4423%
1872
11th to 20thDay
14%15%5%10%8%45%45%5%26%
1980
21st to endDay
14%15%5%7%6%35%445%31%
2232
April1st to 10thDay
22%16%5%7%6%34435%24%
2160
11th to 20thDay
20%11%48%5%33446%31%
2204
21st to endDay
21%11%47%5%34446%31%
2371
May1st to 10thDay
18%10%46%6%35%5%5%6%31%
2520
11th to 20thDay
22%10%35%5%35%5%5%6%32%
2478
21st to endDay
20%9%36%6%3445%6%35%
2725
June1st to 10thDay
22%9%37%5%35%6%5%8%29%
2646
11th to 20thDay
16%8%37%6%45%6%6%7%33%
2700
21st to endDay
19%7%37%7%35%5%6%7%31%
2700
July1st to 10thDay
17%6%36%6%45%6%7%9%32%
2700
11th to 20thDay
17%6%37%6%46%6%6%8%31%
2668
21st to endDay
17%8%36%6%45%6%7%9%30%
2744
August1st to 10thDay
20%8%47%8%35%5%5%8%27%
2462
11th to 20thDay
19%8%36%6%45%5%6%8%31%
2303
21st to endDay
20%8%47%6%45%5%5%7%30%
2477
September1st to 10thDay
20%8%35%6%345%7%6%33%
2160
11th to 20thDay
22%8%36%5%35%46%8%31%
2160
21st to endDay
24%10%46%6%24446%30%
1882
October1st to 10thDay
23%13%37%43435%5%30%
1800
11th to 20thDay
31%20%5%6%6%33435%15%
1800
21st to endDay
30%18%6%6%7%34345%15%
1864
November1st to 10thDay
21%21%6%9%6%2433419%
1494
11th to 20thDay
22%19%8%13%8%3433412%
1520
21st to endDay
26%20%8%13%9%443337%
1520
December1st to 10thDay
19%21%9%13%8%5%5%33311%
1520
11th to 20thDay
17%19%7%11%11%45%5%4312%
1785
21st to endDay
18%19%9%15%11%3433311%
2431
January1st to 10thNight
17%20%9%15%9%36%43311%
2838
11th to 20thNight
16%16%7%12%8%5%7%6%5%413%
2644
21st to endNight
10%14%7%13%11%6%7%6%6%5%15%
2704
February1st to 10thNight
11%15%6%10%11%5%7%6%5%6%18%
2340
11th to 20thNight
13%17%6%12%9%45%5%6%5%18%
2273
21st to endNight
11%13%7%13%9%5%7%6%46%19%
1889
March1st to 10thNight
12%16%6%10%9%46%6%5%5%21%
2074
11th to 20thNight
17%16%7%9%7%36%44423%
1979
21st to endNight
16%12%48%5%45%345%34%
2123
April1st to 10thNight
20%15%6%9%6%3334427%
1800
11th to 20thNight
17%10%48%6%3445%6%32%
1719
21st to endNight
19%10%47%5%3345%7%33%
1589
May1st to 10thNight
16%11%46%7%45%35%6%34%
1440
11th to 20thNight
21%9%35%4345%5%6%34%
1415
21st to endNight
20%8%35%5%345%5%8%35%
1550
June1st to 10thNight
21%7%38%6%35%5%5%7%30%
1310
11th to 20thNight
18%8%36%5%35%45%7%36%
1260
21st to endNight
15%7%25%5%46%6%5%8%37%
1260
July1st to 10thNight
17%5%36%5%35%6%7%9%34%
1260
11th to 20thNight
15%5%25%435%5%6%7%41%
1291
21st to endNight
14%7%37%5%35%5%5%8%36%
1574
August1st to 10thNight
17%6%36%6%35%5%6%8%34%
1474
11th to 20thNight
16%7%36%5%345%6%8%39%
1598
21st to endNight
16%7%37%6%35%5%5%8%34%
1860
September1st to 10thNight
19%8%35%5%345%5%6%38%
1800
11th to 20thNight
21%8%35%5%3435%6%36%
1800
21st to endNight
24%7%36%5%24345%36%
2074
October1st to 10thNight
23%10%46%5%3435%6%33%
2160
11th to 20thNight
28%16%5%8%5%34345%19%
2160
21st to endNight
28%21%47%42334419%
2490
November1st to 10thNight
21%17%7%9%6%34445%21%
2582
11th to 20thNight
21%19%7%11%8%4433416%
2660
21st to endNight
25%22%7%12%9%4433310%
2660
December1st to 10thNight
18%23%8%14%9%3343311%
2660
11th to 20thNight
19%20%7%12%10%47%43312%
3408
21st to endNight
19%18%10%16%10%3332312%
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
77%49%9%1
1329
11th to 20thDay
73%5%6%10%5%1
1358
21st to endDay
70%45%12%9%
1650
February1st to 10thDay
70%47%11%8%
1620
11th to 20thDay
69%5%7%12%6%
1582
21st to endDay
64%6%7%17%5%1
1365
March1st to 10thDay
65%5%6%13%10%1
1875
11th to 20thDay
59%5%8%17%9%2
1980
21st to endDay
55%48%19%10%3
2232
April1st to 10thDay
63%5%10%11%10%2
2160
11th to 20thDay
55%410%19%10%2
2204
21st to endDay
54%6%8%16%14%2
2371
May1st to 10thDay
52%6%12%16%11%3
2520
11th to 20thDay
53%7%9%17%14%1
2482
21st to endDay
50%6%10%20%12%1
2725
June1st to 10thDay
52%8%11%19%10%1
2646
11th to 20thDay
48%8%10%22%11%2
2700
21st to endDay
49%9%12%21%9%1
2700
July1st to 10thDay
45%9%15%23%7%1
2626
11th to 20thDay
47%10%16%19%9%
2587
21st to endDay
50%9%15%20%5%
2591
August1st to 10thDay
52%10%14%20%3
2448
11th to 20thDay
49%11%16%16%8%
2303
21st to endDay
52%8%13%20%7%
2477
September1st to 10thDay
49%9%14%19%8%1
2160
11th to 20thDay
51%8%17%18%5%
2160
21st to endDay
55%7%12%20%6%
1882
October1st to 10thDay
56%7%12%16%8%1
1800
11th to 20thDay
72%5%10%9%31
1800
21st to endDay
73%5%8%9%41
1864
November1st to 10thDay
69%7%12%9%3
1494
11th to 20thDay
77%5%7%8%3
1520
21st to endDay
85%46%42
1520
December1st to 10thDay
79%46%8%2
1520
11th to 20thDay
75%7%5%11%3
1784
21st to endDay
79%47%9%1
2431
January1st to 10thNight
80%46%7%2
2838
11th to 20thNight
73%5%7%9%6%
2644
21st to endNight
68%6%7%12%7%1
2704
February1st to 10thNight
66%6%8%12%8%
2340
11th to 20thNight
67%5%8%13%6%1
2275
21st to endNight
67%5%8%13%7%1
1889
March1st to 10thNight
64%49%12%9%1
2084
11th to 20thNight
64%6%7%13%8%1
1980
21st to endNight
54%5%8%18%14%3
2123
April1st to 10thNight
61%47%14%12%2
1800
11th to 20thNight
52%6%9%21%11%1
1719
21st to endNight
53%6%8%16%15%2
1589
May1st to 10thNight
50%6%12%16%14%3
1440
11th to 20thNight
49%6%10%19%14%1
1416
21st to endNight
48%6%11%19%14%1
1551
June1st to 10thNight
53%7%11%18%10%1
1310
11th to 20thNight
45%7%10%20%14%4
1260
21st to endNight
43%9%14%22%11%1
1260
July1st to 10thNight
43%11%13%25%8%
1225
11th to 20thNight
39%8%18%25%10%
1249
21st to endNight
45%10%17%22%6%
1486
August1st to 10thNight
46%10%17%22%5%
1464
11th to 20thNight
43%8%18%24%7%1
1598
21st to endNight
47%9%17%22%6%
1860
September1st to 10thNight
45%9%16%19%10%1
1800
11th to 20thNight
48%9%17%20%6%
1800
21st to endNight
50%6%14%24%6%
2074
October1st to 10thNight
54%7%13%17%8%1
2160
11th to 20thNight
68%6%11%13%2
2160
21st to endNight
69%6%10%11%41
2490
November1st to 10thNight
65%7%13%12%2
2582
11th to 20thNight
72%7%9%9%3
2660
21st to endNight
81%5%7%6%1
2660
December1st to 10thNight
79%6%7%6%2
2660
11th to 20thNight
78%45%10%3
3408
21st to endNight
80%448%3
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%22%41%12%31
180
11th to 20thDay
18%18%35%21%6%2
164
21st to endDay
18%16%36%21%7%1
206
February1st to 10thDay
23%25%39%10%31
240
11th to 20thDay
24%22%39%13%2
240
21st to endDay
24%21%39%14%2
231
March1st to 10thDay
21%19%38%16%5%1
420
11th to 20thDay
25%19%36%15%5%
420
21st to endDay
24%21%34%15%5%1
462
April1st to 10thDay
30%19%28%17%6%1
420
11th to 20thDay
26%17%29%19%7%2
412
21st to endDay
26%17%33%17%5%2
420
May1st to 10thDay
23%16%35%17%7%1
423
11th to 20thDay
26%17%30%17%6%3
447
21st to endDay
24%18%31%21%5%
485
June1st to 10thDay
25%14%35%19%6%1
576
11th to 20thDay
22%17%32%20%7%2
630
21st to endDay
19%13%31%27%9%2
630
July1st to 10thDay
17%14%34%25%9%1
621
11th to 20thDay
17%13%33%25%11%1
586
21st to endDay
19%11%30%27%11%2
488
August1st to 10thDay
20%8%31%26%11%4
446
11th to 20thDay
20%7%27%27%13%6%
439
21st to endDay
23%13%29%19%11%5%
495
September1st to 10thDay
22%12%35%18%11%2
450
11th to 20thDay
22%12%31%26%8%1
450
21st to endDay
27%15%30%17%9%2
450
October1st to 10thDay
31%13%26%19%9%2
450
11th to 20thDay
37%20%25%12%41
450
21st to endDay
36%14%31%15%4
437
November1st to 10thDay
35%23%32%8%2
188
11th to 20thDay
31%21%33%13%2
180
21st to endDay
37%22%31%7%31
180
December1st to 10thDay
28%15%29%21%6%1
180
11th to 20thDay
29%16%42%9%32
180
21st to endDay
29%16%34%14%5%2
198
January1st to 10thNight
28%13%35%19%5%
950
11th to 20thNight
26%13%33%21%6%
824
21st to endNight
17%11%31%28%12%1
792
February1st to 10thNight
17%18%35%23%6%
720
11th to 20thNight
23%14%35%23%5%
703
21st to endNight
19%19%35%22%5%
592
March1st to 10thNight
22%20%28%23%6%
720
11th to 20thNight
26%20%30%19%41
720
21st to endNight
23%15%33%23%6%1
792
April1st to 10thNight
30%13%28%23%6%1
720
11th to 20thNight
24%17%28%22%9%
655
21st to endNight
25%10%33%25%6%1
509
May1st to 10thNight
21%9%36%25%9%
360
11th to 20thNight
25%9%31%27%8%1
354
21st to endNight
25%10%33%28%5%
389
June1st to 10thNight
21%10%36%26%7%
360
11th to 20thNight
21%9%31%32%7%
360
21st to endNight
18%6%26%35%14%
360
July1st to 10thNight
17%8%29%35%10%1
350
11th to 20thNight
15%5%31%36%13%
348
21st to endNight
14%8%23%40%14%1
394
August1st to 10thNight
19%5%27%32%16%2
400
11th to 20thNight
17%5%28%28%21%1
534
21st to endNight
20%8%26%28%14%3
672
September1st to 10thNight
21%9%31%23%14%1
720
11th to 20thNight
25%9%28%25%11%1
720
21st to endNight
26%9%27%25%11%1
720
October1st to 10thNight
28%13%28%22%8%1
720
11th to 20thNight
37%13%27%15%6%1
720
21st to endNight
40%11%28%17%4
792
November1st to 10thNight
31%15%32%15%6%1
740
11th to 20thNight
33%17%30%15%5%
760
21st to endNight
34%18%31%14%31
760
December1st to 10thNight
32%17%28%16%6%1
760
11th to 20thNight
27%17%30%19%5%2
836
21st to endNight
30%17%26%19%6%1
1045
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