Ste-Félicité
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ste-Félicité clear sky chart from 2005-11-05 to 2017-09-23.

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
26%
14606
9%
46851
5%
14575
31%
14575
11%
36651

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
12%
750
4%
2685
1%
746
16%
746
3%
2377
January16th to endNight
19%
773
8%
2715
4%
773
24%
773
6%
2280
February1st to 15thNight
21%
703
7%
2322
3%
701
26%
701
8%
1869
February16th to endNight
21%
631
6%
1988
3%
631
25%
631
8%
1623
March1st to 15thNight
24%
720
15%
2073
9%
720
30%
720
13%
1615
March16th to endNight
26%
768
16%
2112
7%
768
34%
768
16%
1572
April1st to 15thNight
25%
605
13%
1713
7%
605
29%
605
13%
1344
April16th to endNight
30%
540
16%
1620
10%
540
36%
540
18%
1139
May1st to 15thNight
36%
540
8%
1539
6%
540
38%
540
17%
1175
May16th to endNight
28%
375
9%
1310
5%
374
34%
374
12%
981
June1st to 15thNight
40%
360
4%
1260
3%
360
41%
360
16%
898
June16th to endNight
40%
360
5%
1260
4%
360
41%
360
14%
909
July1st to 15thNight
40%
340
5%
1190
5%
340
41%
340
17%
823
July16th to endNight
48%
376
9%
1290
9%
354
51%
354
18%
875
August1st to 15thNight
50%
491
8%
1562
8%
489
51%
489
19%
1092
August16th to endNight
47%
573
13%
1719
8%
573
50%
573
21%
1187
September1st to 15thNight
39%
625
11%
1834
8%
625
41%
625
20%
1301
September16th to endNight
33%
689
16%
1902
11%
689
38%
689
24%
1282
October1st to 15thNight
31%
660
14%
1951
8%
660
37%
660
17%
1391
October16th to endNight
23%
704
7%
2247
4%
704
27%
704
11%
1777
November1st to 15thNight
17%
723
10%
2414
5%
723
23%
723
8%
1917
November16th to endNight
18%
750
6%
2565
3%
750
21%
750
6%
2164
December1st to 15thNight
8%
750
2%
2700
0%
750
10%
750
2%
2480
December16th to endNight
12%
800
3%
2880
1%
800
14%
800
3%
2580

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%10%47%6%35%446%28%
48081
Night
19%12%5%8%7%45%445%23%
47004
TransparencyDay
57%413%16%6%
47752
Night
63%410%14%6%
46851
SeeingDay
27%9%25%23%11%2
6719
Night
25%13%24%24%10%1
14607

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
18%16%7%14%11%6%5%35%47%
1253
16th to endDay
11%13%6%11%9%6%10%7%4314%
1507
February1st to 15thDay
8%14%411%9%7%10%6%5%5%16%
1539
16th to endDay
14%15%6%10%8%46%5%5%5%18%
1485
March1st to 15thDay
16%12%5%6%5%47%6%45%25%
1876
16th to endDay
14%14%5%6%5%35%346%30%
2112
April1st to 15thDay
20%12%5%5%5%34345%28%
2233
16th to endDay
19%9%35%5%34446%35%
2340
May1st to 15thDay
22%8%36%423446%31%
2422
16th to endDay
26%7%245%2445%6%29%
2805
June1st to 15thDay
21%7%25%5%245%5%7%31%
2700
16th to endDay
23%6%35%435%5%5%8%28%
2700
July1st to 15thDay
16%7%26%5%345%6%8%33%
2700
16th to endDay
16%6%25%5%35%5%6%6%36%
2788
August1st to 15thDay
15%6%36%5%345%5%8%34%
2376
16th to endDay
17%4245%345%5%8%36%
2483
September1st to 15thDay
23%5%25%423436%39%
2124
16th to endDay
20%6%25%424435%40%
1895
October1st to 15thDay
22%9%35%5%34446%30%
1678
16th to endDay
30%13%445%33346%22%
1625
November1st to 15thDay
24%14%6%7%6%2443420%
1444
16th to endDay
23%16%6%12%7%2434315%
1392
December1st to 15thDay
19%15%7%14%14%45%4337%
1260
16th to endDay
19%18%8%12%11%6%5%3237%
1344
January1st to 15thNight
17%17%8%11%12%6%5%4439%
2685
16th to endNight
10%15%6%10%9%7%10%5%4413%
2715
February1st to 15thNight
8%13%6%11%10%7%8%6%45%17%
2321
16th to endNight
15%19%7%9%8%4433418%
1988
March1st to 15thNight
18%13%5%8%7%35%43326%
2061
16th to endNight
16%14%6%5%6%3332432%
2112
April1st to 15thNight
23%14%37%6%24335%25%
1713
16th to endNight
25%7%36%323246%34%
1620
May1st to 15thNight
25%8%38%425%435%27%
1539
16th to endNight
23%8%46%6%35%6%6%5%24%
1308
June1st to 15thNight
22%7%35%6%345%5%6%28%
1260
16th to endNight
22%8%37%5%3445%6%28%
1260
July1st to 15thNight
18%7%37%6%3446%8%29%
1260
16th to endNight
15%5%35%5%35%6%6%9%32%
1378
August1st to 15thNight
16%6%25%6%35%6%6%8%31%
1572
16th to endNight
16%6%25%5%36%6%6%8%32%
1719
September1st to 15thNight
20%6%37%5%34445%35%
1834
16th to endNight
24%41442234442%
1902
October1st to 15thNight
21%9%25%424446%33%
1951
16th to endNight
29%12%45%43444422%
2247
November1st to 15thNight
27%14%5%6%42444420%
2414
16th to endNight
19%18%7%12%6%3434415%
2565
December1st to 15thNight
19%19%9%14%11%443227%
2700
16th to endNight
19%20%7%12%10%5%6%3238%
2880

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
80%37%6%1
1254
16th to endDay
71%5%9%10%3
1507
February1st to 15thDay
66%5%13%11%2
1542
16th to endDay
67%49%14%4
1485
March1st to 15thDay
60%49%17%7%
1887
16th to endDay
55%211%19%9%1
2112
April1st to 15thDay
59%39%18%8%1
2233
16th to endDay
49%310%20%13%1
2340
May1st to 15thDay
52%311%20%9%1
2422
16th to endDay
55%412%17%8%
2809
June1st to 15thDay
52%6%11%17%11%1
2700
16th to endDay
54%6%12%17%8%
2700
July1st to 15thDay
45%6%19%21%6%
2541
16th to endDay
47%5%18%21%7%
2613
August1st to 15thDay
46%6%22%21%3
2362
16th to endDay
43%6%24%19%5%
2483
September1st to 15thDay
47%418%22%6%
2124
16th to endDay
47%416%24%7%
1895
October1st to 15thDay
53%5%15%15%8%
1678
16th to endDay
64%313%13%3
1625
November1st to 15thDay
68%412%11%3
1444
16th to endDay
74%311%8%2
1392
December1st to 15thDay
82%48%4
1260
16th to endDay
83%46%41
1344
January1st to 15thNight
80%47%6%1
2685
16th to endNight
73%46%12%3
2715
February1st to 15thNight
67%49%13%4
2322
16th to endNight
69%47%13%5%
1988
March1st to 15thNight
63%26%19%8%
2073
16th to endNight
57%28%18%11%1
2112
April1st to 15thNight
62%47%11%12%1
1713
16th to endNight
52%37%21%14%1
1620
May1st to 15thNight
59%28%17%10%
1539
16th to endNight
59%5%8%17%8%
1310
June1st to 15thNight
54%411%17%9%1
1260
16th to endNight
55%5%10%16%11%
1260
July1st to 15thNight
51%416%21%5%
1190
16th to endNight
47%7%15%20%9%
1290
August1st to 15thNight
47%8%18%21%4
1562
16th to endNight
46%7%19%22%4
1719
September1st to 15thNight
50%5%13%22%8%
1834
16th to endNight
44%415%23%11%
1902
October1st to 15thNight
51%413%20%7%
1951
16th to endNight
65%312%14%4
2247
November1st to 15thNight
67%312%12%3
2414
16th to endNight
72%5%9%8%2
2565
December1st to 15thNight
85%35%5%
2700
16th to endNight
82%38%41
2880

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
20%26%40%10%3
60
16th to endDay
23%10%35%15%12%1
64
February1st to 15thDay
16%14%31%29%7%2
200
16th to endDay
29%14%25%19%8%1
223
March1st to 15thDay
24%17%27%17%11%1
270
16th to endDay
20%15%28%20%10%3
288
April1st to 15thDay
27%15%26%18%8%3
270
16th to endDay
26%11%32%18%7%4
270
May1st to 15thDay
28%7%28%21%9%4
367
16th to endDay
33%8%25%22%7%2
519
June1st to 15thDay
28%7%20%27%15%1
495
16th to endDay
28%5%22%26%13%2
495
July1st to 15thDay
24%425%27%13%4
475
16th to endDay
22%420%32%15%3
459
August1st to 15thDay
19%324%31%16%4
313
16th to endDay
21%5%24%28%15%4
332
September1st to 15thDay
29%324%26%12%3
315
16th to endDay
24%10%29%21%11%2
283
October1st to 15thDay
26%15%25%20%10%2
230
16th to endDay
42%12%17%15%8%3
240
November1st to 15thDay
37%14%24%14%7%1
235
16th to endDay
31%14%23%22%6%1
192
December1st to 15thDay
30%6%40%16%5%1
60
16th to endDay
34%20%25%18%1
64
January1st to 15thNight
24%20%31%17%5%
750
16th to endNight
17%21%29%23%7%
773
February1st to 15thNight
13%16%32%26%9%
704
16th to endNight
25%12%27%22%9%2
631
March1st to 15thNight
24%13%27%23%9%
720
16th to endNight
23%14%25%22%11%1
768
April1st to 15thNight
30%15%21%21%9%1
605
16th to endNight
27%11%21%25%11%2
540
May1st to 15thNight
27%6%20%29%13%1
540
16th to endNight
27%6%26%26%10%1
375
June1st to 15thNight
25%417%35%16%
360
16th to endNight
24%419%33%16%1
360
July1st to 15thNight
21%6%18%35%14%3
340
16th to endNight
15%5%19%35%20%2
376
August1st to 15thNight
20%315%33%24%3
491
16th to endNight
17%420%36%18%2
573
September1st to 15thNight
24%6%22%29%15%1
625
16th to endNight
26%8%26%26%9%1
689
October1st to 15thNight
26%13%22%24%11%1
660
16th to endNight
37%13%19%20%8%
704
November1st to 15thNight
34%15%24%18%5%1
723
16th to endNight
29%17%24%20%6%1
750
December1st to 15thNight
28%25%25%15%3
750
16th to endNight
28%18%24%19%6%2
800
Page generated at 2017-09-24 09:15:50. Version ac04

Copyright 2017 A. Danko


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