Parc des Îles de St-Timothée
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Parc des Îles de St-Timothée clear sky chart from 2005-11-05 to 2017-10-31.

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
30%
14828
13%
47359
8%
14797
36%
14797
15%
34470

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
16%
720
7%
2506
3%
716
21%
716
7%
2028
January16th to endNight
21%
768
9%
2688
5%
768
28%
768
10%
2061
February1st to 15thNight
18%
704
8%
2296
4%
701
23%
701
8%
1867
February16th to endNight
22%
631
12%
1896
5%
631
30%
631
12%
1461
March1st to 15thNight
21%
720
12%
2160
7%
720
27%
720
13%
1651
March16th to endNight
31%
768
19%
1992
9%
768
37%
768
22%
1433
April1st to 15thNight
26%
718
16%
1796
5%
718
32%
718
20%
1356
April16th to endNight
29%
636
16%
1716
6%
636
36%
636
21%
1228
May1st to 15thNight
30%
387
17%
1467
12%
387
41%
387
16%
988
May16th to endNight
34%
374
12%
1497
11%
374
43%
374
17%
980
June1st to 15thNight
32%
360
9%
1440
9%
360
40%
360
12%
1022
June16th to endNight
41%
360
9%
1440
11%
360
47%
360
19%
906
July1st to 15thNight
51%
340
14%
1360
19%
340
58%
340
24%
791
July16th to endNight
52%
376
13%
1418
15%
354
56%
354
23%
842
August1st to 15thNight
52%
372
15%
1443
15%
370
56%
370
22%
882
August16th to endNight
50%
761
20%
1907
11%
761
53%
761
34%
1245
September1st to 15thNight
50%
720
14%
1800
8%
720
51%
720
29%
1250
September16th to endNight
47%
717
22%
1962
16%
717
51%
717
30%
1277
October1st to 15thNight
33%
720
17%
2130
10%
720
42%
720
20%
1485
October16th to endNight
24%
768
10%
2449
7%
768
30%
768
13%
1854
November1st to 15thNight
26%
700
15%
2277
10%
700
33%
700
14%
1670
November16th to endNight
21%
720
11%
2511
7%
720
27%
720
9%
1920
December1st to 15thNight
15%
720
7%
2520
2%
720
21%
720
7%
2058
December16th to endNight
11%
768
8%
2688
3%
768
17%
768
6%
2215

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%8%36%5%3445%7%33%
48396
Night
18%9%46%5%34445%31%
47528
Cloud CoverDay
17%7%36%5%3445%7%33%
48405
Night
18%9%36%5%34445%31%
47534
TransparencyDay
49%7%11%20%9%1
48083
Night
53%6%10%18%9%1
47359
SeeingDay
21%9%27%23%12%4
5740
Night
23%10%28%26%10%
14829

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
21%14%5%7%7%25%34421%
1432
16th to endDay
13%14%48%7%35%45%8%23%
1536
February1st to 15thDay
15%12%410%7%46%45%6%22%
1563
16th to endDay
16%11%5%9%6%25%346%27%
1577
March1st to 15thDay
17%10%5%7%8%34445%28%
1790
16th to endDay
18%7%34424346%38%
2229
April1st to 15thDay
21%7%36%6%25%445%32%
2152
16th to endDay
19%6%345%2345%6%38%
2244
May1st to 15thDay
19%5%346%3445%6%34%
2493
16th to endDay
17%6%35%5%2445%7%36%
2618
June1st to 15thDay
22%6%25%5%345%5%7%32%
2520
16th to endDay
16%5%26%5%36%5%6%8%33%
2520
July1st to 15thDay
11%5%35%4345%6%8%41%
2520
16th to endDay
12%4245%35%6%8%9%37%
2654
August1st to 15thDay
12%5%26%6%36%5%6%9%35%
2495
16th to endDay
9%3144345%7%9%46%
2292
September1st to 15thDay
15%425%42445%7%44%
2160
16th to endDay
12%5%235%23447%48%
1997
October1st to 15thDay
19%7%35%43445%7%34%
1827
16th to endDay
23%10%36%6%24446%27%
1773
November1st to 15thDay
15%10%35%5%35%6%5%6%31%
1581
16th to endDay
19%12%48%5%3345%6%25%
1447
December1st to 15thDay
23%13%6%8%5%37%5%46%16%
1440
16th to endDay
26%15%47%7%3444417%
1536
January1st to 15thNight
17%16%5%9%7%46%44419%
2506
16th to endNight
13%16%5%6%6%35%445%25%
2688
February1st to 15thNight
14%13%6%11%8%46%5%4420%
2294
16th to endNight
15%13%5%8%6%4435%5%26%
1896
March1st to 15thNight
20%10%47%6%4444428%
2147
16th to endNight
19%9%35%42424438%
1992
April1st to 15thNight
25%7%35%434345%31%
1796
16th to endNight
21%8%24423445%36%
1716
May1st to 15thNight
21%7%26%5%2325%6%34%
1467
16th to endNight
20%5%25%5%35%45%7%35%
1495
June1st to 15thNight
23%7%36%5%2445%7%29%
1440
16th to endNight
16%5%25%4246%6%7%37%
1440
July1st to 15thNight
10%3245%35%6%7%8%42%
1440
16th to endNight
11%434435%5%6%8%42%
1514
August1st to 15thNight
11%5%25%5%25%45%8%41%
1453
16th to endNight
12%41443345%6%48%
1907
September1st to 15thNight
15%5%25%5%34445%43%
1800
16th to endNight
17%413423446%46%
1962
October1st to 15thNight
17%9%35%5%24446%37%
2130
16th to endNight
24%8%37%6%34445%27%
2449
November1st to 15thNight
20%9%46%5%34445%30%
2277
16th to endNight
21%11%47%6%2444426%
2511
December1st to 15thNight
23%15%6%6%6%34445%19%
2520
16th to endNight
24%17%5%7%6%2433419%
2688

Percentage Cloud Cover SE (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
21%14%5%7%7%35%445%21%
1432
16th to endDay
13%14%48%8%35%448%24%
1536
February1st to 15thDay
14%12%49%7%46%45%6%22%
1563
16th to endDay
16%11%5%8%7%24346%27%
1577
March1st to 15thDay
17%10%5%7%7%345%35%28%
1800
16th to endDay
18%7%345%24346%38%
2228
April1st to 15thDay
21%7%35%6%25%45%432%
2152
16th to endDay
19%6%25%5%3445%6%37%
2244
May1st to 15thDay
19%6%35%5%35%45%6%34%
2493
16th to endDay
17%6%35%5%2445%7%36%
2618
June1st to 15thDay
22%6%35%5%34447%32%
2520
16th to endDay
16%435%5%36%5%6%8%33%
2520
July1st to 15thDay
11%5%25%4346%6%8%40%
2520
16th to endDay
12%4245%35%6%8%9%37%
2654
August1st to 15thDay
12%5%26%5%36%6%6%9%35%
2495
16th to endDay
9%3144246%7%9%47%
2292
September1st to 15thDay
15%4244235%47%44%
2160
16th to endDay
12%5%24434347%48%
1997
October1st to 15thDay
19%8%25%435%45%6%34%
1827
16th to endDay
22%10%36%6%24446%27%
1773
November1st to 15thDay
15%10%35%5%35%5%5%7%31%
1581
16th to endDay
20%11%38%6%2445%6%26%
1447
December1st to 15thDay
23%13%5%8%5%36%5%5%6%16%
1440
16th to endDay
26%15%47%7%2344417%
1536
January1st to 15thNight
17%16%5%9%6%36%445%19%
2506
16th to endNight
14%15%5%6%7%35%445%26%
2688
February1st to 15thNight
14%13%6%11%8%46%5%4420%
2287
16th to endNight
15%13%49%6%35%345%27%
1896
March1st to 15thNight
20%10%47%6%3434428%
2160
16th to endNight
18%10%25%5%2334438%
1992
April1st to 15thNight
25%8%35%434346%30%
1796
16th to endNight
21%8%25%5%23345%36%
1716
May1st to 15thNight
22%7%26%5%24346%34%
1467
16th to endNight
19%5%26%6%25%35%7%35%
1495
June1st to 15thNight
23%7%36%4245%5%7%28%
1440
16th to endNight
15%6%34425%6%7%7%37%
1440
July1st to 15thNight
10%4146%25%6%6%8%42%
1440
16th to endNight
11%424435%5%7%8%41%
1514
August1st to 15thNight
11%6%245%245%5%9%41%
1453
16th to endNight
12%415%433447%47%
1907
September1st to 15thNight
15%5%26%5%3435%5%42%
1800
16th to endNight
17%314423446%46%
1962
October1st to 15thNight
18%8%36%4245%35%37%
2130
16th to endNight
23%7%47%6%35%335%28%
2449
November1st to 15thNight
20%9%36%6%345%4431%
2277
16th to endNight
21%11%47%6%2444426%
2511
December1st to 15thNight
23%15%6%7%6%2444420%
2520
16th to endNight
24%17%5%8%5%2433419%
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
65%6%8%13%5%
1433
16th to endDay
59%6%12%14%6%
1536
February1st to 15thDay
62%7%10%16%3
1565
16th to endDay
58%5%10%14%9%1
1577
March1st to 15thDay
58%5%12%14%7%1
1800
16th to endDay
46%6%10%18%14%3
2229
April1st to 15thDay
52%5%7%20%11%2
2152
16th to endDay
46%5%8%19%15%4
2244
May1st to 15thDay
48%6%9%19%14%1
2493
16th to endDay
45%7%11%21%12%1
2622
June1st to 15thDay
51%7%10%20%10%
2520
16th to endDay
46%8%12%20%10%
2520
July1st to 15thDay
37%8%13%28%11%
2371
16th to endDay
39%8%17%24%8%
2487
August1st to 15thDay
43%9%16%22%8%
2481
16th to endDay
30%9%17%29%12%
2292
September1st to 15thDay
39%7%12%27%13%
2160
16th to endDay
36%5%12%32%12%
1997
October1st to 15thDay
49%6%11%23%8%
1827
16th to endDay
57%6%12%16%5%
1773
November1st to 15thDay
50%7%13%19%9%
1581
16th to endDay
59%7%10%15%6%
1447
December1st to 15thDay
67%8%10%11%1
1440
16th to endDay
69%5%10%9%4
1536
January1st to 15thNight
66%6%9%11%4
2506
16th to endNight
60%6%9%15%7%
2688
February1st to 15thNight
66%7%8%14%3
2296
16th to endNight
59%6%8%15%9%
1896
March1st to 15thNight
59%5%9%16%8%1
2160
16th to endNight
49%49%17%14%4
1992
April1st to 15thNight
54%46%19%13%1
1796
16th to endNight
49%47%18%15%3
1716
May1st to 15thNight
50%47%16%16%4
1467
16th to endNight
46%7%10%20%13%1
1497
June1st to 15thNight
54%7%9%18%9%
1440
16th to endNight
42%7%14%20%13%
1440
July1st to 15thNight
34%9%12%28%14%
1360
16th to endNight
35%9%16%23%14%
1418
August1st to 15thNight
38%8%18%21%11%
1443
16th to endNight
35%6%14%28%14%
1907
September1st to 15thNight
42%5%11%26%13%
1800
16th to endNight
37%7%9%30%14%
1962
October1st to 15thNight
48%6%10%24%10%
2130
16th to endNight
58%6%12%16%5%
2449
November1st to 15thNight
55%6%11%16%8%1
2277
16th to endNight
60%6%10%16%5%
2511
December1st to 15thNight
66%7%10%13%1
2520
16th to endNight
69%6%9%10%4
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
23%21%18%26%10%
60
16th to endDay
40%7%28%18%4
64
February1st to 15thDay
30%17%40%10%1
88
16th to endDay
29%8%33%24%4
236
March1st to 15thDay
20%14%36%21%7%
270
16th to endDay
27%9%28%20%11%2
288
April1st to 15thDay
28%13%31%16%8%1
270
16th to endDay
20%13%28%21%12%3
270
May1st to 15thDay
25%12%28%20%9%4
288
16th to endDay
21%12%30%19%13%2
331
June1st to 15thDay
27%9%24%26%9%2
315
16th to endDay
19%5%29%30%12%2
315
July1st to 15thDay
14%5%29%30%16%3
305
16th to endDay
14%422%35%18%4
326
August1st to 15thDay
16%420%34%18%5%
313
16th to endDay
10%5%27%26%17%12%
332
September1st to 15thDay
16%6%22%24%16%13%
315
16th to endDay
12%6%27%21%22%10%
314
October1st to 15thDay
22%9%24%19%19%4
315
16th to endDay
32%13%25%21%7%
299
November1st to 15thDay
22%14%26%20%14%1
235
16th to endDay
34%10%28%17%8%
67
December1st to 15thDay
30%11%28%25%5%
60
16th to endDay
45%7%35%10%
64
January1st to 15thNight
24%15%33%21%4
720
16th to endNight
22%14%33%22%6%
768
February1st to 15thNight
21%13%34%25%5%
704
16th to endNight
22%12%34%25%5%
631
March1st to 15thNight
25%12%33%23%4
720
16th to endNight
23%9%29%28%7%
768
April1st to 15thNight
27%11%28%27%4
718
16th to endNight
25%10%28%24%10%
636
May1st to 15thNight
24%7%28%28%10%
387
16th to endNight
21%431%29%11%
375
June1st to 15thNight
26%7%26%28%9%
360
16th to endNight
16%5%30%33%13%1
360
July1st to 15thNight
10%326%39%17%1
340
16th to endNight
12%325%41%14%1
376
August1st to 15thNight
14%418%41%19%1
372
16th to endNight
15%324%32%22%1
761
September1st to 15thNight
18%5%21%37%15%2
720
16th to endNight
18%6%23%27%22%2
717
October1st to 15thNight
23%9%27%25%14%
720
16th to endNight
28%13%27%23%6%
768
November1st to 15thNight
24%12%29%22%9%
700
16th to endNight
25%17%25%19%11%
720
December1st to 15thNight
32%15%29%20%3
720
16th to endNight
34%13%31%15%31
768
Page generated at 2017-11-01 17:23:34. Version ac04

Copyright 2017 A. Danko


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