CEGEP Beauce-Appalaches
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the CEGEP Beauce-Appalaches clear sky chart from 2005-11-05 to 2017-08-12.

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
25%
14542
11%
46499
6%
14510
31%
14510
13%
35159

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
11%
720
8%
2506
4%
716
17%
716
6%
2104
January16th to endNight
15%
768
8%
2688
2%
768
23%
768
7%
2191
February1st to 15thNight
15%
704
7%
2334
3%
701
21%
701
7%
1912
February16th to endNight
16%
631
10%
1893
3%
631
24%
631
10%
1515
March1st to 15thNight
18%
720
14%
2145
7%
720
26%
720
13%
1635
March16th to endNight
27%
768
16%
2046
7%
768
34%
768
17%
1521
April1st to 15thNight
22%
709
16%
1787
5%
709
28%
709
16%
1372
April16th to endNight
25%
540
15%
1620
6%
540
32%
540
16%
1154
May1st to 15thNight
26%
498
13%
1578
9%
498
32%
498
15%
1129
May16th to endNight
29%
375
10%
1479
10%
374
37%
374
12%
1058
June1st to 15thNight
30%
360
7%
1260
6%
360
34%
360
12%
964
June16th to endNight
39%
360
9%
1260
9%
360
43%
360
18%
854
July1st to 15thNight
42%
340
8%
1340
10%
340
46%
340
17%
874
July16th to endNight
48%
376
10%
1418
13%
354
50%
354
17%
924
August1st to 15thNight
50%
435
10%
1484
9%
433
52%
433
19%
1013
August16th to endNight
47%
577
15%
1627
9%
577
50%
577
27%
1064
September1st to 15thNight
38%
660
11%
1708
5%
660
40%
660
25%
1201
September16th to endNight
39%
657
18%
1815
11%
657
45%
657
28%
1180
October1st to 15thNight
31%
660
16%
1894
9%
660
37%
660
19%
1386
October16th to endNight
19%
704
9%
2288
4%
704
26%
704
10%
1790
November1st to 15thNight
26%
700
14%
2277
10%
700
33%
700
13%
1708
November16th to endNight
22%
737
12%
2514
8%
737
28%
737
10%
1939
December1st to 15thNight
12%
750
5%
2700
2%
750
16%
750
5%
2266
December16th to endNight
12%
793
7%
2838
3%
793
17%
793
4%
2405

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%47%6%34446%26%
47476
Night
18%11%48%6%34445%28%
46669
TransparencyDay
59%5%10%16%7%
47164
Night
59%5%10%17%7%
46499
SeeingDay
29%13%26%19%8%2
5970
Night
27%12%27%23%8%
14542

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%16%7%12%9%2444416%
1432
16th to endDay
12%14%6%12%10%33446%19%
1536
February1st to 15thDay
12%17%7%11%10%46%43317%
1524
16th to endDay
14%18%6%12%5%35%44419%
1580
March1st to 15thDay
18%15%7%7%6%4333425%
1805
16th to endDay
16%12%5%7%6%34335%29%
2178
April1st to 15thDay
22%13%46%42233430%
2161
16th to endDay
23%10%35%423335%32%
2340
May1st to 15thDay
24%10%46%5%24345%27%
2385
16th to endDay
24%8%37%6%3446%6%24%
2633
June1st to 15thDay
27%8%35%5%345%5%8%23%
2700
16th to endDay
21%8%48%7%45%446%24%
2700
July1st to 15thDay
17%6%35%7%36%6%6%8%28%
2537
16th to endDay
20%7%36%7%35%5%6%8%24%
2654
August1st to 15thDay
19%7%36%7%46%6%6%7%24%
2367
16th to endDay
16%7%35%5%45%447%36%
2220
September1st to 15thDay
22%7%25%42345%7%34%
1921
16th to endDay
18%7%25%32345%7%38%
1815
October1st to 15thDay
23%11%45%42344429%
1735
16th to endDay
27%16%37%6%2333419%
1584
November1st to 15thDay
21%15%37%5%24345%25%
1581
16th to endDay
21%15%6%8%5%23435%24%
1445
December1st to 15thDay
23%18%6%10%7%2435%215%
1260
16th to endDay
23%17%8%10%7%3423314%
1383
January1st to 15thNight
17%16%6%12%8%3443417%
2506
16th to endNight
12%14%7%11%8%46%5%4419%
2688
February1st to 15thNight
10%13%6%13%11%5%7%335%19%
2333
16th to endNight
14%16%6%10%7%2443324%
1893
March1st to 15thNight
17%12%6%7%6%34335%29%
2132
16th to endNight
14%11%5%6%5%35%45%432%
2046
April1st to 15thNight
22%13%45%42345%5%28%
1787
16th to endNight
22%8%26%5%34335%34%
1620
May1st to 15thNight
22%8%46%434445%30%
1578
16th to endNight
22%7%37%6%33445%31%
1477
June1st to 15thNight
26%8%37%6%34345%25%
1260
16th to endNight
17%6%36%4345%6%7%34%
1260
July1st to 15thNight
17%5%25%5%36%46%7%35%
1420
16th to endNight
15%7%25%5%25%5%5%8%36%
1514
August1st to 15thNight
14%6%25%5%35%46%8%35%
1494
16th to endNight
14%425%5%245%5%8%40%
1627
September1st to 15thNight
20%7%35%5%23346%38%
1708
16th to endNight
18%5%24313346%46%
1815
October1st to 15thNight
21%9%26%5%23345%33%
1894
16th to endNight
25%15%47%42334325%
2288
November1st to 15thNight
20%10%46%5%34446%27%
2277
16th to endNight
20%15%5%8%5%2323427%
2514
December1st to 15thNight
23%16%7%11%8%3333416%
2700
16th to endNight
22%16%7%11%7%3433216%
2838

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
72%47%10%5%
1433
16th to endDay
66%5%6%14%5%
1536
February1st to 15thDay
73%46%11%4
1527
16th to endDay
69%46%11%7%1
1580
March1st to 15thDay
62%38%13%10%1
1815
16th to endDay
59%47%16%11%1
2178
April1st to 15thDay
58%27%18%10%3
2161
16th to endDay
54%48%18%11%2
2340
May1st to 15thDay
59%38%17%9%
2385
16th to endDay
59%6%10%16%6%
2637
June1st to 15thDay
60%5%10%16%6%
2700
16th to endDay
60%5%10%18%6%
2700
July1st to 15thDay
51%7%15%18%6%
2388
16th to endDay
57%7%12%18%4
2487
August1st to 15thDay
56%8%16%15%3
2353
16th to endDay
47%5%14%24%8%
2220
September1st to 15thDay
48%5%14%20%10%
1921
16th to endDay
44%5%11%27%10%
1815
October1st to 15thDay
57%411%20%5%
1735
16th to endDay
68%38%16%2
1584
November1st to 15thDay
61%312%14%6%
1581
16th to endDay
63%5%9%15%5%
1445
December1st to 15thDay
74%47%11%2
1260
16th to endDay
77%35%7%5%
1383
January1st to 15thNight
71%5%6%11%4
2506
16th to endNight
68%6%7%12%5%
2688
February1st to 15thNight
69%46%13%5%
2334
16th to endNight
66%37%11%9%
1893
March1st to 15thNight
59%48%17%9%1
2145
16th to endNight
53%5%8%17%11%2
2046
April1st to 15thNight
58%35%19%11%2
1787
16th to endNight
53%49%17%13%3
1620
May1st to 15thNight
54%49%17%12%
1578
16th to endNight
56%5%11%17%8%
1479
June1st to 15thNight
61%5%8%16%6%
1260
16th to endNight
47%7%15%21%8%
1260
July1st to 15thNight
45%8%17%19%8%
1340
16th to endNight
46%7%17%19%9%
1418
August1st to 15thNight
46%8%18%22%3
1484
16th to endNight
41%5%18%27%6%
1627
September1st to 15thNight
47%414%25%8%
1708
16th to endNight
39%5%14%29%10%
1815
October1st to 15thNight
53%410%22%9%
1894
16th to endNight
63%49%16%5%
2288
November1st to 15thNight
57%6%12%15%6%1
2277
16th to endNight
63%49%17%5%
2514
December1st to 15thNight
74%37%11%2
2700
16th to endNight
75%37%8%4
2838

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
23%21%41%13%
60
16th to endDay
28%21%34%9%41
64
February1st to 15thDay
29%20%24%19%6%
153
16th to endDay
24%19%30%19%5%
239
March1st to 15thDay
31%19%27%16%4
270
16th to endDay
27%16%24%18%9%4
288
April1st to 15thDay
35%15%25%16%32
270
16th to endDay
30%15%29%14%6%3
270
May1st to 15thDay
39%10%26%14%5%2
288
16th to endDay
27%17%32%18%21
346
June1st to 15thDay
33%10%23%23%8%1
495
16th to endDay
27%8%30%22%9%1
495
July1st to 15thDay
24%8%32%21%10%2
322
16th to endDay
26%7%23%30%11%
326
August1st to 15thDay
26%8%25%21%15%2
297
16th to endDay
25%6%25%23%12%6%
268
September1st to 15thDay
22%7%25%21%16%6%
255
16th to endDay
23%14%22%16%15%7%
254
October1st to 15thDay
29%12%21%19%11%5%
246
16th to endDay
42%12%20%17%6%
240
November1st to 15thDay
30%16%23%21%7%
235
16th to endDay
33%17%19%15%11%3
165
December1st to 15thDay
46%15%26%8%11
60
16th to endDay
42%20%31%6%
64
January1st to 15thNight
27%19%32%17%2
720
16th to endNight
24%15%35%18%5%
768
February1st to 15thNight
19%19%35%20%4
704
16th to endNight
27%15%32%19%4
631
March1st to 15thNight
29%14%33%19%3
720
16th to endNight
23%16%26%23%8%1
768
April1st to 15thNight
31%13%27%21%5%
709
16th to endNight
26%15%26%23%7%
540
May1st to 15thNight
26%10%28%23%8%1
498
16th to endNight
27%8%26%28%8%
375
June1st to 15thNight
31%6%23%29%9%
360
16th to endNight
20%5%29%31%11%
360
July1st to 15thNight
20%6%25%32%14%
340
16th to endNight
17%323%41%14%
376
August1st to 15thNight
17%320%35%22%
435
16th to endNight
18%423%34%18%1
577
September1st to 15thNight
25%7%23%28%13%1
660
16th to endNight
22%8%27%26%14%1
657
October1st to 15thNight
27%11%25%24%10%1
660
16th to endNight
36%13%25%17%6%
704
November1st to 15thNight
27%13%25%24%8%
700
16th to endNight
32%14%25%17%8%1
737
December1st to 15thNight
35%17%26%16%3
750
16th to endNight
35%17%24%17%5%
793
Page generated at 2017-08-13 14:16:14. Version ac04

Copyright 2017 A. Danko


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