Saint-Michel-des-Saints
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saint-Michel-des-Saints clear sky chart from 2005-11-05 to 2017-12-01.

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
24%
14858
11%
47784
6%
14826
31%
14826
13%
35500

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
7%
2506
2%
716
18%
716
7%
2033
January16th to endNight
17%
768
9%
2688
4%
768
25%
768
9%
2081
February1st to 15thNight
15%
704
10%
2328
3%
701
25%
701
9%
1817
February16th to endNight
15%
631
11%
1911
4%
631
24%
631
11%
1474
March1st to 15thNight
17%
720
11%
2160
6%
720
24%
720
11%
1690
March16th to endNight
26%
768
18%
1995
7%
768
34%
768
18%
1444
April1st to 15thNight
21%
718
14%
1796
5%
718
26%
718
16%
1396
April16th to endNight
23%
615
14%
1695
5%
615
30%
615
18%
1196
May1st to 15thNight
31%
360
14%
1440
13%
360
39%
360
14%
1005
May16th to endNight
24%
375
11%
1497
7%
374
36%
374
14%
1025
June1st to 15thNight
28%
360
5%
1440
4%
360
33%
360
12%
1027
June16th to endNight
40%
360
5%
1440
6%
360
44%
360
16%
973
July1st to 15thNight
41%
340
9%
1360
11%
340
46%
340
21%
841
July16th to endNight
42%
376
11%
1418
11%
354
47%
354
19%
899
August1st to 15thNight
50%
359
12%
1430
13%
357
56%
357
19%
928
August16th to endNight
43%
727
16%
1873
8%
727
47%
727
28%
1275
September1st to 15thNight
38%
720
11%
1800
5%
720
40%
720
26%
1274
September16th to endNight
38%
717
18%
1962
11%
717
43%
717
28%
1300
October1st to 15thNight
26%
720
16%
2133
7%
720
36%
720
18%
1497
October16th to endNight
19%
768
9%
2466
5%
768
25%
768
10%
1956
November1st to 15thNight
21%
760
14%
2496
8%
760
30%
760
11%
1885
November16th to endNight
18%
780
11%
2730
6%
780
24%
780
8%
2156
December1st to 15thNight
12%
724
5%
2532
1%
724
17%
724
6%
2092
December16th to endNight
9%
768
9%
2688
2%
768
17%
768
5%
2236

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
18%11%47%6%35%446%27%
48653
Night
16%11%47%6%34446%28%
47953
TransparencyDay
58%6%10%16%8%
48340
Night
56%6%11%17%7%
47784
SeeingDay
26%15%30%17%7%2
5757
Night
23%14%31%21%8%
14858

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
15%16%7%11%7%46%44417%
1432
16th to endDay
10%13%7%11%9%35%5%5%6%20%
1536
February1st to 15thDay
7%15%6%11%11%5%7%45%5%19%
1533
16th to endDay
14%18%5%9%8%35%34322%
1561
March1st to 15thDay
12%14%6%10%7%3444425%
1790
16th to endDay
13%12%5%8%6%24446%33%
2228
April1st to 15thDay
20%14%5%6%5%33335%28%
2152
16th to endDay
20%11%45%5%24335%33%
2274
May1st to 15thDay
22%10%27%5%25%345%28%
2511
16th to endDay
23%9%36%6%24445%28%
2618
June1st to 15thDay
26%7%35%5%35%346%26%
2520
16th to endDay
21%7%37%7%36%5%5%7%25%
2520
July1st to 15thDay
16%7%46%6%46%5%6%8%27%
2520
16th to endDay
13%8%47%6%36%5%5%8%29%
2654
August1st to 15thDay
20%8%37%7%46%5%5%6%23%
2520
16th to endDay
13%6%36%6%35%45%8%35%
2317
September1st to 15thDay
21%7%25%43335%6%35%
2160
16th to endDay
19%7%24433337%40%
1998
October1st to 15thDay
23%12%36%6%34345%27%
1824
16th to endDay
25%16%5%8%6%3333419%
1757
November1st to 15thDay
17%15%47%6%35%445%25%
1690
16th to endDay
17%17%6%9%7%3333423%
1560
December1st to 15thDay
21%18%5%8%6%34435%17%
1442
16th to endDay
20%17%7%10%6%35%33417%
1536
January1st to 15thNight
15%16%7%11%8%45%5%46%14%
2506
16th to endNight
9%14%6%11%10%46%5%6%6%19%
2688
February1st to 15thNight
7%14%7%10%11%5%6%6%45%20%
2326
16th to endNight
13%14%5%9%8%45%45%5%22%
1911
March1st to 15thNight
17%14%5%6%8%45%445%24%
2147
16th to endNight
12%12%46%5%34445%35%
1995
April1st to 15thNight
21%11%47%5%23345%29%
1796
16th to endNight
19%10%45%423346%36%
1695
May1st to 15thNight
20%9%35%5%23445%33%
1440
16th to endNight
22%7%26%5%34347%33%
1495
June1st to 15thNight
21%9%37%434448%27%
1440
16th to endNight
17%6%35%5%35%45%8%34%
1440
July1st to 15thNight
12%5%245%35%45%9%40%
1440
16th to endNight
11%6%25%5%35%5%5%7%41%
1514
August1st to 15thNight
12%5%25%5%35%5%6%9%37%
1440
16th to endNight
12%6%25%5%345%5%7%41%
1873
September1st to 15thNight
17%6%25%43445%7%38%
1800
16th to endNight
17%6%34422346%44%
1962
October1st to 15thNight
17%9%46%5%34346%35%
2133
16th to endNight
24%14%47%6%33445%22%
2466
November1st to 15thNight
17%12%5%6%6%445%5%5%27%
2496
16th to endNight
18%15%6%9%6%24345%21%
2730
December1st to 15thNight
18%18%7%9%7%3444415%
2532
16th to endNight
17%17%8%11%7%4444414%
2688

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
70%46%13%5%
1433
16th to endDay
61%5%8%15%7%
1536
February1st to 15thDay
65%48%14%6%
1535
16th to endDay
66%35%13%9%1
1561
March1st to 15thDay
61%48%13%10%1
1800
16th to endDay
53%38%17%13%3
2228
April1st to 15thDay
59%37%16%10%3
2152
16th to endDay
54%5%7%16%13%2
2274
May1st to 15thDay
57%5%7%17%11%1
2511
16th to endDay
57%6%9%16%9%1
2622
June1st to 15thDay
57%7%9%15%8%1
2520
16th to endDay
56%8%11%16%7%
2520
July1st to 15thDay
51%8%13%18%7%
2371
16th to endDay
52%9%13%16%6%
2487
August1st to 15thDay
58%9%12%15%3
2506
16th to endDay
44%9%16%20%8%
2317
September1st to 15thDay
49%6%14%20%8%
2160
16th to endDay
44%5%14%26%9%
1998
October1st to 15thDay
58%6%10%17%6%
1824
16th to endDay
69%410%11%4
1757
November1st to 15thDay
60%6%10%13%7%
1690
16th to endDay
65%5%8%13%7%
1560
December1st to 15thDay
68%5%9%12%3
1442
16th to endDay
70%47%9%8%
1536
January1st to 15thNight
69%39%12%4
2506
16th to endNight
62%5%9%13%7%1
2688
February1st to 15thNight
63%5%8%15%6%
2328
16th to endNight
61%5%9%12%10%
1911
March1st to 15thNight
62%48%15%7%1
2160
16th to endNight
51%48%19%14%2
1995
April1st to 15thNight
57%5%6%17%10%1
1796
16th to endNight
49%5%10%19%12%2
1695
May1st to 15thNight
53%5%8%17%11%3
1440
16th to endNight
51%6%11%19%10%
1497
June1st to 15thNight
54%7%13%16%7%
1440
16th to endNight
47%8%13%18%10%
1440
July1st to 15thNight
39%8%19%21%9%1
1360
16th to endNight
40%9%16%25%7%
1418
August1st to 15thNight
41%10%19%24%4
1430
16th to endNight
40%8%18%26%7%
1873
September1st to 15thNight
44%7%16%21%9%
1800
16th to endNight
41%5%16%28%8%
1962
October1st to 15thNight
50%5%12%21%9%
2133
16th to endNight
63%5%10%15%4
2466
November1st to 15thNight
57%7%10%15%6%1
2496
16th to endNight
65%5%8%14%4
2730
December1st to 15thNight
70%5%9%11%3
2532
16th to endNight
71%5%7%9%5%
2688

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
28%18%31%16%5%
60
16th to endDay
23%21%35%10%7%
64
February1st to 15thDay
26%20%43%8%1
83
16th to endDay
30%22%27%15%4
220
March1st to 15thDay
26%20%32%17%2
270
16th to endDay
23%18%29%17%7%3
288
April1st to 15thDay
29%21%26%14%6%1
270
16th to endDay
25%21%30%11%10%1
270
May1st to 15thDay
37%15%26%12%6%2
288
16th to endDay
28%18%29%16%6%1
331
June1st to 15thDay
33%14%28%14%7%1
315
16th to endDay
24%10%38%19%5%1
315
July1st to 15thDay
20%11%38%21%6%1
305
16th to endDay
16%7%35%26%11%2
326
August1st to 15thDay
22%7%29%25%11%3
313
16th to endDay
17%10%32%20%11%7%
332
September1st to 15thDay
26%11%24%20%10%6%
315
16th to endDay
21%9%28%21%12%6%
314
October1st to 15thDay
26%16%29%16%9%3
315
16th to endDay
35%17%24%15%6%
295
November1st to 15thDay
30%17%26%17%7%
254
16th to endDay
40%27%20%6%32
90
December1st to 15thDay
33%23%30%10%3
60
16th to endDay
40%26%28%4
64
January1st to 15thNight
22%20%36%15%4
720
16th to endNight
16%18%39%20%5%
768
February1st to 15thNight
15%20%40%17%5%
704
16th to endNight
22%16%38%17%4
631
March1st to 15thNight
27%18%30%19%3
720
16th to endNight
19%17%32%22%7%1
768
April1st to 15thNight
28%16%29%20%5%
718
16th to endNight
24%16%31%18%8%
615
May1st to 15thNight
26%10%28%24%9%
360
16th to endNight
25%10%37%19%7%
375
June1st to 15thNight
25%9%30%27%7%
360
16th to endNight
18%5%29%33%11%1
360
July1st to 15thNight
14%5%34%32%12%1
340
16th to endNight
14%331%35%13%1
376
August1st to 15thNight
15%5%22%37%19%
359
16th to endNight
17%7%27%29%15%2
727
September1st to 15thNight
22%6%28%28%12%1
720
16th to endNight
22%8%28%23%14%1
717
October1st to 15thNight
24%14%30%19%9%
720
16th to endNight
33%15%26%18%5%
768
November1st to 15thNight
25%17%30%16%8%1
760
16th to endNight
28%21%25%15%6%1
780
December1st to 15thNight
29%19%31%15%3
724
16th to endNight
31%18%33%12%31
768
Page generated at 2017-12-02 09:14:23. Version ac04

Copyright 2017 A. Danko


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