Pointe Sainte-Foy
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pointe Sainte-Foy clear sky chart from 2005-11-05 to 2018-02-22.

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
28%
15287
12%
48967
7%
15256
35%
15256
15%
35962

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
15%
780
10%
2716
3%
776
23%
776
8%
2134
January16th to endNight
22%
832
11%
2912
5%
832
31%
832
10%
2187
February1st to 15thNight
22%
763
10%
2557
4%
761
29%
761
11%
1958
February16th to endNight
19%
659
12%
1976
5%
659
27%
659
11%
1543
March1st to 15thNight
20%
720
14%
2160
8%
720
29%
720
15%
1606
March16th to endNight
33%
768
17%
2022
8%
768
39%
768
21%
1466
April1st to 15thNight
28%
718
15%
1796
6%
718
32%
718
18%
1384
April16th to endNight
27%
543
16%
1623
7%
543
35%
543
20%
1127
May1st to 15thNight
29%
453
13%
1533
10%
453
36%
453
15%
1092
May16th to endNight
29%
375
10%
1485
10%
374
37%
374
14%
1045
June1st to 15thNight
33%
360
7%
1260
5%
360
37%
360
14%
922
June16th to endNight
40%
360
7%
1260
8%
360
41%
360
16%
883
July1st to 15thNight
43%
340
8%
1341
10%
340
47%
340
18%
890
July16th to endNight
48%
376
9%
1418
13%
354
50%
354
18%
932
August1st to 15thNight
51%
413
10%
1484
10%
411
54%
411
18%
1002
August16th to endNight
45%
645
15%
1791
9%
645
48%
645
26%
1191
September1st to 15thNight
40%
720
11%
1845
5%
720
42%
720
26%
1300
September16th to endNight
43%
717
18%
1980
12%
717
47%
717
29%
1314
October1st to 15thNight
33%
720
16%
2083
8%
720
41%
720
21%
1477
October16th to endNight
24%
768
10%
2496
5%
768
30%
768
13%
1860
November1st to 15thNight
29%
760
15%
2472
10%
760
36%
760
14%
1791
November16th to endNight
25%
803
13%
2761
6%
803
34%
803
12%
2062
December1st to 15thNight
15%
825
6%
2925
1%
825
21%
825
7%
2368
December16th to endNight
14%
869
11%
3071
4%
869
22%
869
8%
2428

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%8%36%5%3445%6%30%
49281
Night
19%10%46%5%34445%30%
49137
TransparencyDay
53%6%12%18%8%
48969
Night
55%5%11%17%8%
48967
SeeingDay
25%11%27%22%11%2
6464
Night
25%9%28%27%8%
15288

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
20%13%47%7%44445%22%
1552
16th to endDay
11%12%6%10%6%45%5%5%426%
1664
February1st to 15thDay
11%13%5%10%6%4445%6%26%
1631
16th to endDay
15%12%5%7%7%35%5%45%25%
1644
March1st to 15thDay
18%11%5%6%434435%32%
1790
16th to endDay
15%9%35%5%35%446%35%
2199
April1st to 15thDay
23%9%35%43433433%
2152
16th to endDay
23%7%25%423336%36%
2337
May1st to 15thDay
24%6%35%5%34446%32%
2427
16th to endDay
21%6%37%6%45%5%5%5%28%
2627
June1st to 15thDay
21%5%35%6%36%5%6%7%28%
2700
16th to endDay
22%7%35%6%35%5%5%7%26%
2700
July1st to 15thDay
15%5%35%5%35%6%6%9%31%
2536
16th to endDay
16%6%26%5%45%6%6%8%30%
2654
August1st to 15thDay
16%6%25%6%46%5%7%9%27%
2454
16th to endDay
13%5%16%43445%8%40%
2408
September1st to 15thDay
19%6%2442345%7%38%
2115
16th to endDay
17%5%24323347%44%
1980
October1st to 15thDay
23%6%26%5%2445%6%31%
1875
16th to endDay
26%10%36%5%24445%24%
1728
November1st to 15thDay
21%8%37%6%4445%430%
1716
16th to endDay
25%13%37%5%2323426%
1525
December1st to 15thDay
26%15%46%5%3333423%
1365
16th to endDay
22%16%6%7%5%23445%22%
1502
January1st to 15thNight
19%16%5%9%7%24445%22%
2716
16th to endNight
13%13%6%8%6%45%5%5%5%24%
2912
February1st to 15thNight
9%13%5%10%9%45%5%45%24%
2556
16th to endNight
17%13%7%9%6%3434426%
1976
March1st to 15thNight
19%10%37%5%34445%31%
2147
16th to endNight
15%11%25%5%34446%36%
2022
April1st to 15thNight
23%10%46%43345%5%28%
1796
16th to endNight
23%7%26%413335%38%
1623
May1st to 15thNight
23%6%35%6%3445%432%
1533
16th to endNight
26%7%25%434445%31%
1483
June1st to 15thNight
24%7%25%6%3436%6%27%
1260
16th to endNight
21%5%45%5%3446%6%31%
1260
July1st to 15thNight
17%5%345%35%46%7%36%
1421
16th to endNight
15%5%26%5%35%5%6%7%35%
1514
August1st to 15thNight
15%5%346%35%6%5%9%33%
1494
16th to endNight
14%425%6%35%5%48%38%
1791
September1st to 15thNight
20%6%25%423347%38%
1845
16th to endNight
19%5%23413346%45%
1980
October1st to 15thNight
20%7%25%5%24446%36%
2083
16th to endNight
26%10%36%423445%28%
2496
November1st to 15thNight
20%7%36%5%34446%32%
2472
16th to endNight
24%10%46%42434428%
2761
December1st to 15thNight
23%15%5%9%6%3433420%
2925
16th to endNight
21%15%5%9%6%2334322%
3071

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
63%6%9%13%6%
1553
16th to endDay
58%5%10%18%7%
1664
February1st to 15thDay
58%414%14%6%1
1634
16th to endDay
58%6%9%16%7%2
1644
March1st to 15thDay
54%411%15%12%1
1800
16th to endDay
49%6%9%18%12%2
2199
April1st to 15thDay
54%39%17%9%4
2152
16th to endDay
49%411%18%13%2
2337
May1st to 15thDay
52%5%12%17%11%1
2427
16th to endDay
56%7%10%17%7%
2631
June1st to 15thDay
52%8%13%16%8%1
2700
16th to endDay
55%8%11%16%8%
2700
July1st to 15thDay
45%10%17%20%6%
2387
16th to endDay
51%8%17%17%5%
2487
August1st to 15thDay
49%10%18%16%3
2440
16th to endDay
40%8%16%26%7%
2408
September1st to 15thDay
44%6%16%22%9%
2115
16th to endDay
41%5%15%29%8%
1980
October1st to 15thDay
51%6%13%21%6%
1875
16th to endDay
61%6%11%18%3
1728
November1st to 15thDay
56%6%11%19%6%
1716
16th to endDay
62%410%16%5%
1525
December1st to 15thDay
65%410%13%5%
1365
16th to endDay
65%47%13%7%
1502
January1st to 15thNight
65%48%15%4
2716
16th to endNight
60%49%16%7%
2912
February1st to 15thNight
60%5%11%15%6%
2557
16th to endNight
62%5%8%13%9%1
1976
March1st to 15thNight
56%5%9%15%11%2
2160
16th to endNight
49%5%9%18%12%3
2022
April1st to 15thNight
56%46%17%11%2
1796
16th to endNight
48%49%17%15%3
1623
May1st to 15thNight
54%5%9%16%13%1
1533
16th to endNight
53%6%11%16%11%
1485
June1st to 15thNight
57%5%13%16%6%1
1260
16th to endNight
51%6%11%18%11%
1260
July1st to 15thNight
45%8%16%20%7%
1341
16th to endNight
45%7%18%19%8%
1418
August1st to 15thNight
44%10%19%21%4
1484
16th to endNight
42%6%17%26%6%
1791
September1st to 15thNight
46%5%13%23%9%
1845
16th to endNight
41%5%15%26%10%
1980
October1st to 15thNight
49%5%11%23%8%
2083
16th to endNight
57%5%13%17%5%
2496
November1st to 15thNight
52%7%13%17%8%
2472
16th to endNight
59%411%17%6%
2761
December1st to 15thNight
68%5%10%11%4
2925
16th to endNight
65%48%12%7%
3071

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
27%18%32%20%1
90
16th to endDay
19%27%33%15%4
96
February1st to 15thDay
24%20%35%12%7%
162
16th to endDay
25%9%33%25%5%
265
March1st to 15thDay
23%16%29%22%6%1
270
16th to endDay
21%11%25%23%13%3
288
April1st to 15thDay
30%11%25%20%11%1
270
16th to endDay
27%11%29%19%9%2
270
May1st to 15thDay
32%8%29%19%6%3
288
16th to endDay
24%14%31%20%8%1
340
June1st to 15thDay
26%8%24%28%11%
495
16th to endDay
26%8%26%26%11%1
495
July1st to 15thDay
20%9%25%27%14%2
321
16th to endDay
16%5%27%30%15%2
326
August1st to 15thDay
18%6%24%27%18%4
313
16th to endDay
19%7%25%21%17%8%
332
September1st to 15thDay
21%11%23%21%17%5%
315
16th to endDay
16%11%24%22%19%5%
314
October1st to 15thDay
27%9%25%21%12%3
304
16th to endDay
34%14%21%19%9%
288
November1st to 15thDay
27%15%24%20%11%
280
16th to endDay
39%9%25%17%7%
156
December1st to 15thDay
36%15%27%14%32
90
16th to endDay
32%20%31%10%41
96
January1st to 15thNight
26%14%31%23%3
780
16th to endNight
20%13%32%26%6%
832
February1st to 15thNight
15%12%36%27%7%
764
16th to endNight
26%10%33%24%4
659
March1st to 15thNight
25%11%35%22%4
720
16th to endNight
20%9%29%29%9%1
768
April1st to 15thNight
29%10%26%27%7%
718
16th to endNight
26%10%30%23%9%
543
May1st to 15thNight
25%9%29%27%6%
453
16th to endNight
33%5%25%28%6%
375
June1st to 15thNight
27%5%26%32%7%
360
16th to endNight
21%324%37%11%
360
July1st to 15thNight
19%325%32%16%1
340
16th to endNight
17%321%46%11%
376
August1st to 15thNight
19%216%40%19%
413
16th to endNight
17%424%35%15%1
645
September1st to 15thNight
23%325%31%14%1
720
16th to endNight
22%6%23%29%17%
717
October1st to 15thNight
24%8%26%30%8%1
720
16th to endNight
32%11%26%22%5%
768
November1st to 15thNight
24%12%26%25%9%
760
16th to endNight
30%12%25%22%8%
803
December1st to 15thNight
32%12%28%20%6%
825
16th to endNight
30%15%28%19%5%1
869
Page generated at 2018-02-23 11:21:28. Version ac04

Copyright 2018 A. Danko


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