Observatoire de St-Felicien
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoire de St-Felicien 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
27%
15180
10%
48965
6%
15148
31%
15148
13%
37208

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
18%
780
8%
2716
5%
776
23%
776
8%
2216
January16th to endNight
28%
832
7%
2912
4%
832
32%
832
9%
2306
February1st to 15thNight
29%
764
10%
2613
6%
761
36%
761
11%
2011
February16th to endNight
25%
659
11%
1979
7%
659
31%
659
12%
1560
March1st to 15thNight
26%
720
13%
2160
9%
720
31%
720
14%
1655
March16th to endNight
28%
768
17%
2010
8%
768
34%
768
19%
1489
April1st to 15thNight
27%
718
11%
1796
5%
718
30%
718
16%
1407
April16th to endNight
27%
552
15%
1632
7%
552
35%
552
19%
1156
May1st to 15thNight
27%
370
11%
1450
10%
370
34%
370
14%
1018
May16th to endNight
27%
375
10%
1441
7%
374
37%
374
14%
1004
June1st to 15thNight
31%
360
6%
1260
3%
360
34%
360
15%
885
June16th to endNight
35%
360
4%
1260
2%
360
36%
360
15%
882
July1st to 15thNight
39%
340
5%
1287
5%
340
41%
340
17%
853
July16th to endNight
40%
376
7%
1418
8%
354
44%
354
14%
972
August1st to 15thNight
42%
359
10%
1430
10%
357
46%
357
13%
1005
August16th to endNight
37%
648
11%
1794
5%
648
42%
648
20%
1297
September1st to 15thNight
34%
720
9%
1813
4%
720
36%
720
24%
1322
September16th to endNight
29%
717
13%
1980
7%
717
33%
717
21%
1426
October1st to 15thNight
25%
720
12%
2121
6%
720
32%
720
17%
1539
October16th to endNight
19%
768
8%
2496
4%
768
25%
768
9%
2020
November1st to 15thNight
19%
760
11%
2495
6%
760
27%
760
10%
1943
November16th to endNight
18%
809
6%
2857
5%
809
21%
809
8%
2313
December1st to 15thNight
17%
825
6%
2925
2%
825
21%
825
7%
2404
December16th to endNight
22%
880
9%
3120
5%
880
27%
880
7%
2525

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
17%10%47%6%35%45%6%26%
49289
Night
17%11%48%6%35%45%6%26%
49132
TransparencyDay
57%5%11%16%7%
48975
Night
58%6%12%15%6%
48965
SeeingDay
23%8%29%23%11%3
6415
Night
23%9%30%26%8%1
15180

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
14%15%7%11%8%46%5%4418%
1549
16th to endDay
11%12%5%9%8%5%6%5%5%7%21%
1664
February1st to 15thDay
8%11%6%9%12%6%9%6%5%5%19%
1577
16th to endDay
12%14%5%10%8%46%35%423%
1641
March1st to 15thDay
14%13%6%7%6%35%5%45%27%
1790
16th to endDay
14%11%47%425%45%6%31%
2213
April1st to 15thDay
18%12%5%8%6%2334428%
2152
16th to endDay
20%8%37%6%34335%32%
2328
May1st to 15thDay
21%9%36%424445%33%
2511
16th to endDay
19%8%37%6%24445%31%
2672
June1st to 15thDay
19%7%36%5%35%5%5%7%29%
2700
16th to endDay
21%6%26%7%36%5%6%6%26%
2700
July1st to 15thDay
15%7%37%6%46%6%6%9%26%
2592
16th to endDay
14%6%37%7%46%5%7%7%29%
2654
August1st to 15thDay
17%8%47%6%5%6%5%6%7%24%
2517
16th to endDay
13%8%47%7%46%5%6%8%28%
2396
September1st to 15thDay
18%7%36%6%3445%7%32%
2146
16th to endDay
19%7%37%6%34347%33%
1980
October1st to 15thDay
20%10%37%6%3435%5%27%
1838
16th to endDay
26%12%37%6%3445%5%20%
1728
November1st to 15thDay
18%13%5%10%7%45%43422%
1690
16th to endDay
20%14%5%8%7%3445%6%19%
1430
December1st to 15thDay
18%18%48%9%3445%417%
1365
16th to endDay
18%14%7%8%8%34435%21%
1456
January1st to 15thNight
15%16%7%10%8%34445%17%
2716
16th to endNight
11%13%7%11%8%46%7%5%5%18%
2912
February1st to 15thNight
8%11%6%11%9%5%7%6%46%22%
2611
16th to endNight
13%15%6%9%8%34435%24%
1979
March1st to 15thNight
15%12%5%7%5%37%5%5%6%25%
2147
16th to endNight
12%12%47%5%35%446%32%
2010
April1st to 15thNight
20%12%5%5%6%3434427%
1796
16th to endNight
19%7%36%5%4345%5%35%
1632
May1st to 15thNight
20%10%46%5%25%44432%
1450
16th to endNight
20%8%35%444446%32%
1439
June1st to 15thNight
18%8%26%435%6%47%30%
1260
16th to endNight
17%6%36%5%36%5%6%7%30%
1260
July1st to 15thNight
15%5%25%6%36%5%7%8%33%
1365
16th to endNight
12%6%36%6%46%5%6%7%34%
1514
August1st to 15thNight
15%7%27%6%445%6%8%30%
1440
16th to endNight
14%6%25%6%35%7%6%7%32%
1794
September1st to 15thNight
18%7%35%5%33446%36%
1813
16th to endNight
19%6%25%5%345%5%5%36%
1980
October1st to 15thNight
19%9%35%5%35%35%6%31%
2121
16th to endNight
27%12%36%5%34445%20%
2496
November1st to 15thNight
21%12%37%6%345%46%24%
2495
16th to endNight
20%13%5%10%6%35%35%5%19%
2857
December1st to 15thNight
18%17%6%9%7%35%43419%
2925
16th to endNight
16%14%6%9%8%46%445%19%
3120

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
68%5%10%10%4
1550
16th to endDay
63%39%16%6%
1664
February1st to 15thDay
65%410%12%6%
1579
16th to endDay
63%6%8%14%7%
1641
March1st to 15thDay
58%37%17%11%1
1800
16th to endDay
52%49%20%10%1
2213
April1st to 15thDay
60%28%16%9%2
2152
16th to endDay
54%47%17%14%1
2328
May1st to 15thDay
52%410%19%12%1
2511
16th to endDay
54%6%8%17%11%1
2676
June1st to 15thDay
52%6%9%18%11%1
2700
16th to endDay
55%7%10%16%8%
2700
July1st to 15thDay
51%7%16%19%3
2442
16th to endDay
54%8%15%17%5%
2487
August1st to 15thDay
55%9%16%15%2
2503
16th to endDay
52%7%16%19%3
2396
September1st to 15thDay
50%7%16%19%6%
2146
16th to endDay
51%6%16%19%5%
1980
October1st to 15thDay
58%5%13%15%5%1
1838
16th to endDay
65%6%13%11%3
1728
November1st to 15thDay
66%5%12%11%4
1690
16th to endDay
66%415%10%2
1430
December1st to 15thDay
68%6%11%10%3
1365
16th to endDay
67%39%11%7%
1456
January1st to 15thNight
69%410%10%4
2716
16th to endNight
65%6%11%13%4
2912
February1st to 15thNight
62%410%15%6%
2613
16th to endNight
63%49%15%6%
1979
March1st to 15thNight
59%47%16%10%
2160
16th to endNight
52%48%22%10%1
2010
April1st to 15thNight
60%38%17%8%2
1796
16th to endNight
50%49%19%13%1
1632
May1st to 15thNight
54%410%14%14%1
1450
16th to endNight
53%411%16%11%2
1441
June1st to 15thNight
50%8%10%20%8%1
1260
16th to endNight
50%8%12%16%10%1
1260
July1st to 15thNight
45%8%15%23%6%
1287
16th to endNight
48%9%11%23%6%
1418
August1st to 15thNight
49%11%17%18%3
1430
16th to endNight
45%11%19%20%2
1794
September1st to 15thNight
47%6%17%20%7%
1813
16th to endNight
48%7%16%22%4
1980
October1st to 15thNight
53%5%15%18%7%
2121
16th to endNight
65%6%11%11%4
2496
November1st to 15thNight
61%6%12%13%5%
2495
16th to endNight
67%6%13%10%2
2857
December1st to 15thNight
68%6%12%9%2
2925
16th to endNight
67%6%10%10%4
3120

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
21%13%28%25%11%
90
16th to endDay
19%6%29%32%10%2
96
February1st to 15thDay
13%5%30%38%8%2
104
16th to endDay
24%9%37%20%7%
262
March1st to 15thDay
21%17%25%25%7%2
270
16th to endDay
21%11%30%23%10%1
288
April1st to 15thDay
24%12%29%24%7%1
270
16th to endDay
22%9%28%25%12%1
270
May1st to 15thDay
27%7%28%20%10%4
288
16th to endDay
22%14%27%27%6%2
385
June1st to 15thDay
23%7%30%21%13%3
495
16th to endDay
24%5%29%25%11%3
495
July1st to 15thDay
19%432%27%11%4
376
16th to endDay
21%224%28%19%4
326
August1st to 15thDay
23%421%28%15%6%
313
16th to endDay
17%7%31%24%9%8%
332
September1st to 15thDay
24%6%31%16%17%3
315
16th to endDay
19%9%31%21%14%3
314
October1st to 15thDay
22%10%37%14%13%2
308
16th to endDay
32%12%30%20%4
288
November1st to 15thDay
28%13%35%13%6%2
254
16th to endDay
38%12%28%15%31
90
December1st to 15thDay
28%8%21%27%10%3
90
16th to endDay
28%10%26%27%6%2
96
January1st to 15thNight
23%9%32%26%7%
780
16th to endNight
18%9%27%31%10%
832
February1st to 15thNight
13%6%34%32%10%1
764
16th to endNight
22%8%32%27%8%
659
March1st to 15thNight
21%14%30%27%5%
720
16th to endNight
19%13%31%26%8%
768
April1st to 15thNight
28%10%26%28%4
718
16th to endNight
24%11%30%26%6%
552
May1st to 15thNight
25%8%31%25%8%
370
16th to endNight
23%7%34%24%9%1
375
June1st to 15thNight
23%6%31%27%9%1
360
16th to endNight
17%6%31%32%11%1
360
July1st to 15thNight
17%7%30%29%15%
340
16th to endNight
14%331%37%11%1
376
August1st to 15thNight
17%326%31%18%2
359
16th to endNight
18%8%29%27%13%3
648
September1st to 15thNight
22%7%29%27%11%1
720
16th to endNight
21%8%36%23%8%1
717
October1st to 15thNight
23%7%37%22%8%
720
16th to endNight
36%10%26%17%7%
768
November1st to 15thNight
28%17%27%17%7%1
760
16th to endNight
29%12%30%20%6%
809
December1st to 15thNight
27%10%31%22%6%
825
16th to endNight
25%11%27%26%7%1
880
Page generated at 2018-02-23 11:21:29. Version ac04

Copyright 2018 A. Danko


Observatoire de St-Felicien Clear Sky Chart |Charts Home