Chibougamau
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chibougamau clear sky chart from 2005-11-05 to 2017-09-16.

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
27%
14415
8%
46471
5%
14383
30%
14383
10%
37426

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
20%
720
5%
2506
4%
716
23%
716
5%
2206
January16th to endNight
26%
768
7%
2688
5%
768
29%
768
7%
2261
February1st to 15thNight
34%
704
8%
2377
8%
701
38%
701
8%
1962
February16th to endNight
24%
631
9%
1961
7%
631
28%
631
10%
1615
March1st to 15thNight
31%
720
13%
2160
10%
720
36%
720
14%
1660
March16th to endNight
30%
768
15%
1995
7%
768
34%
768
16%
1555
April1st to 15thNight
26%
718
11%
1796
5%
718
30%
718
17%
1404
April16th to endNight
30%
506
14%
1586
10%
506
36%
506
16%
1161
May1st to 15thNight
31%
360
11%
1440
10%
360
38%
360
14%
1015
May16th to endNight
31%
375
8%
1472
7%
374
36%
374
13%
1033
June1st to 15thNight
34%
360
5%
1200
1%
360
35%
360
17%
843
June16th to endNight
42%
360
3%
1080
0%
360
42%
360
19%
783
July1st to 15thNight
39%
340
3%
1192
2%
340
39%
340
17%
810
July16th to endNight
44%
376
8%
1418
11%
354
46%
354
15%
964
August1st to 15thNight
45%
359
8%
1430
11%
357
46%
357
14%
1012
August16th to endNight
36%
625
8%
1771
6%
625
38%
625
16%
1369
September1st to 15thNight
37%
720
8%
1800
4%
720
38%
720
18%
1387
September16th to endNight
30%
661
11%
1796
6%
661
33%
661
18%
1346
October1st to 15thNight
23%
660
10%
1980
6%
660
28%
660
12%
1582
October16th to endNight
14%
704
4%
2280
3%
704
15%
704
4%
2073
November1st to 15thNight
15%
700
6%
2385
4%
700
19%
700
5%
2098
November16th to endNight
14%
734
3%
2602
2%
734
16%
734
4%
2357
December1st to 15thNight
16%
750
1%
2700
0%
750
17%
750
3%
2449
December16th to endNight
21%
796
6%
2856
5%
796
24%
796
6%
2481

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%45%5%45%21%
48290
Night
18%13%5%9%7%45%5%45%19%
46635
TransparencyDay
64%5%9%13%6%
47971
Night
66%5%9%13%5%
46472
SeeingDay
26%8%26%23%11%3
6154
Night
25%8%27%25%10%1
14415

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
16%17%7%13%8%5%6%7%5%5%7%
1432
16th to endDay
12%14%6%11%10%5%8%7%8%5%9%
1536
February1st to 15thDay
7%13%6%13%11%5%8%8%6%5%13%
1483
16th to endDay
9%15%7%12%10%5%6%5%5%6%15%
1512
March1st to 15thDay
13%11%6%9%8%45%7%6%5%22%
1790
16th to endDay
11%13%6%7%7%45%5%45%27%
2227
April1st to 15thDay
19%13%6%8%6%34345%23%
2152
16th to endDay
18%11%5%9%5%35%445%26%
2383
May1st to 15thDay
19%9%47%6%34446%30%
2511
16th to endDay
21%9%36%6%35%446%27%
2639
June1st to 15thDay
21%7%46%5%25%45%6%28%
2757
16th to endDay
19%7%37%7%36%5%6%6%25%
2880
July1st to 15thDay
19%9%46%6%45%6%5%7%23%
2690
16th to endDay
19%9%35%6%46%5%5%7%26%
2654
August1st to 15thDay
23%10%47%7%46%45%6%18%
2520
16th to endDay
22%9%47%7%45%5%46%21%
2416
September1st to 15thDay
23%11%27%6%34446%25%
2160
16th to endDay
26%10%37%5%24335%25%
1852
October1st to 15thDay
27%13%5%7%6%3333420%
1650
16th to endDay
32%20%6%9%5%3322210%
1592
November1st to 15thDay
25%23%8%8%6%2322313%
1473
16th to endDay
23%22%9%11%6%45%2237%
1356
December1st to 15thDay
20%20%8%14%7%5%5%5%335%
1260
16th to endDay
17%15%8%13%8%5%7%5%448%
1365
January1st to 15thNight
17%17%7%12%9%5%7%6%45%6%
2506
16th to endNight
11%14%7%13%9%49%9%6%48%
2688
February1st to 15thNight
8%12%6%10%10%6%11%9%6%5%11%
2375
16th to endNight
11%17%6%11%11%445%5%5%16%
1961
March1st to 15thNight
11%13%6%8%7%46%5%5%6%23%
2147
16th to endNight
12%15%5%8%6%45%445%27%
1995
April1st to 15thNight
20%12%5%7%6%33345%26%
1796
16th to endNight
18%10%47%7%2434431%
1586
May1st to 15thNight
18%9%48%7%3344431%
1440
16th to endNight
22%11%35%5%24436%29%
1471
June1st to 15thNight
22%8%26%5%3346%6%30%
1200
16th to endNight
18%5%36%5%36%6%5%6%32%
1080
July1st to 15thNight
20%6%37%43446%8%30%
1266
16th to endNight
17%7%26%5%3446%7%34%
1514
August1st to 15thNight
18%9%247%345%6%8%28%
1440
16th to endNight
19%8%48%6%345%5%6%27%
1771
September1st to 15thNight
24%8%36%5%25%345%31%
1800
16th to endNight
22%8%47%5%33446%31%
1796
October1st to 15thNight
24%11%47%5%25%445%23%
1980
16th to endNight
32%20%6%8%6%333229%
2280
November1st to 15thNight
27%19%6%9%7%3433311%
2385
16th to endNight
20%22%8%12%8%444238%
2602
December1st to 15thNight
19%19%8%13%9%5%6%4436%
2700
16th to endNight
15%17%8%12%9%5%7%5%6%47%
2856

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
77%47%10%
1433
16th to endDay
71%46%10%7%
1536
February1st to 15thDay
69%45%11%7%
1485
16th to endDay
70%47%12%5%
1512
March1st to 15thDay
61%5%7%13%12%
1800
16th to endDay
58%38%15%11%1
2227
April1st to 15thDay
63%47%15%8%1
2152
16th to endDay
58%7%8%14%10%
2383
May1st to 15thDay
55%5%9%18%11%
2511
16th to endDay
56%5%11%17%7%1
2643
June1st to 15thDay
55%5%7%18%11%
2757
16th to endDay
56%8%9%15%10%
2880
July1st to 15thDay
57%7%12%16%5%
2535
16th to endDay
56%8%14%15%4
2487
August1st to 15thDay
64%8%12%12%1
2506
16th to endDay
61%8%12%15%2
2416
September1st to 15thDay
59%6%11%14%7%
2160
16th to endDay
61%5%13%16%3
1852
October1st to 15thDay
68%410%9%5%
1650
16th to endDay
82%36%6%1
1592
November1st to 15thDay
78%37%8%11
1473
16th to endDay
84%36%4
1356
December1st to 15thDay
84%25%6%1
1260
16th to endDay
78%26%7%4
1365
January1st to 15thNight
78%46%8%1
2506
16th to endNight
72%47%10%4
2688
February1st to 15thNight
68%7%7%10%7%
2377
16th to endNight
68%46%14%5%
1961
March1st to 15thNight
61%37%14%11%
2160
16th to endNight
58%5%7%18%8%1
1995
April1st to 15thNight
60%48%15%9%1
1796
16th to endNight
56%49%16%12%
1586
May1st to 15thNight
55%410%14%12%2
1440
16th to endNight
55%48%18%11%
1473
June1st to 15thNight
52%5%10%18%13%
1200
16th to endNight
49%8%12%20%9%
1080
July1st to 15thNight
49%6%15%22%6%
1192
16th to endNight
49%7%12%25%5%
1418
August1st to 15thNight
50%9%20%16%2
1430
16th to endNight
56%7%15%17%2
1771
September1st to 15thNight
55%6%12%17%7%
1800
16th to endNight
54%6%16%20%3
1796
October1st to 15thNight
62%6%9%13%6%1
1980
16th to endNight
82%346%2
2280
November1st to 15thNight
78%46%7%3
2385
16th to endNight
82%36%5%
2602
December1st to 15thNight
83%45%5%1
2700
16th to endNight
77%48%8%2
2856

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
16%15%30%28%10%
60
16th to endDay
34%6%25%18%12%3
64
February1st to 15thDay
8%5%28%45%12%1
75
16th to endDay
19%445%18%11%1
171
March1st to 15thDay
18%13%26%27%12%1
270
16th to endDay
20%7%31%29%8%2
288
April1st to 15thDay
26%11%28%22%7%4
270
16th to endDay
22%10%33%22%6%4
270
May1st to 15thDay
25%7%26%24%13%2
288
16th to endDay
25%7%29%24%10%2
352
June1st to 15thDay
27%9%26%23%10%2
552
16th to endDay
21%8%26%27%13%2
675
July1st to 15thDay
26%6%25%25%13%3
469
16th to endDay
24%6%23%23%18%5%
326
August1st to 15thDay
30%8%16%22%15%7%
313
16th to endDay
28%6%24%20%10%8%
332
September1st to 15thDay
30%7%26%21%9%4
315
16th to endDay
28%8%28%19%12%2
257
October1st to 15thDay
29%11%23%21%11%2
255
16th to endDay
37%13%21%17%7%2
241
November1st to 15thDay
40%9%26%18%3
127
16th to endDay
43%16%18%13%6%1
60
December1st to 15thDay
35%6%28%21%8%
60
16th to endDay
29%17%26%17%6%3
64
January1st to 15thNight
24%9%32%23%9%
720
16th to endNight
18%10%28%29%12%
768
February1st to 15thNight
13%7%28%34%12%2
704
16th to endNight
22%7%30%25%12%1
631
March1st to 15thNight
18%13%27%30%8%1
720
16th to endNight
19%9%32%28%8%1
768
April1st to 15thNight
25%10%28%24%10%
718
16th to endNight
23%8%31%25%10%
506
May1st to 15thNight
23%5%31%27%11%
360
16th to endNight
26%7%29%26%8%1
375
June1st to 15thNight
25%5%26%31%11%
360
16th to endNight
20%7%26%31%12%1
360
July1st to 15thNight
26%422%30%14%1
340
16th to endNight
21%322%36%15%
376
August1st to 15thNight
24%218%29%22%2
359
16th to endNight
24%6%23%26%14%3
625
September1st to 15thNight
30%5%22%26%13%2
720
16th to endNight
27%8%28%26%8%1
661
October1st to 15thNight
30%9%29%21%7%
660
16th to endNight
43%7%23%16%7%1
704
November1st to 15thNight
35%13%25%17%7%1
700
16th to endNight
30%13%28%19%7%1
734
December1st to 15thNight
27%10%31%20%7%1
750
16th to endNight
24%11%30%22%8%1
796
Page generated at 2017-09-17 12:05:43. Version ac04

Copyright 2017 A. Danko


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