Parc des Grands Jardins
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Parc des Grands Jardins clear sky chart from 2005-11-05 to 2017-12-04.

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
19%
14911
13%
47820
5%
14881
29%
14881
12%
33606

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
10%
725
15%
2539
3%
721
24%
721
9%
1744
January16th to endNight
16%
768
16%
2688
3%
768
32%
768
11%
1811
February1st to 15thNight
14%
703
16%
2385
4%
701
29%
701
11%
1576
February16th to endNight
11%
631
14%
1893
3%
631
25%
631
10%
1381
March1st to 15thNight
14%
720
17%
2151
6%
720
28%
720
12%
1532
March16th to endNight
19%
768
19%
2035
5%
768
29%
768
16%
1435
April1st to 15thNight
16%
697
16%
1775
3%
697
25%
697
12%
1333
April16th to endNight
20%
540
16%
1620
5%
540
29%
540
14%
1139
May1st to 15thNight
23%
450
10%
1530
6%
450
31%
450
13%
1086
May16th to endNight
21%
374
10%
1401
4%
374
32%
374
12%
1002
June1st to 15thNight
32%
360
7%
1260
4%
360
36%
360
13%
887
June16th to endNight
26%
360
5%
1260
3%
360
29%
360
15%
877
July1st to 15thNight
29%
340
6%
1251
5%
340
34%
340
16%
841
July16th to endNight
29%
376
9%
1418
8%
354
38%
354
15%
919
August1st to 15thNight
35%
413
10%
1484
7%
411
41%
411
17%
980
August16th to endNight
29%
612
14%
1758
5%
612
36%
612
22%
1146
September1st to 15thNight
27%
720
10%
1854
4%
720
31%
720
21%
1327
September16th to endNight
23%
717
16%
1980
6%
717
31%
717
21%
1353
October1st to 15thNight
20%
720
15%
2091
5%
720
29%
720
15%
1489
October16th to endNight
16%
768
11%
2496
5%
768
23%
768
8%
1862
November1st to 15thNight
18%
760
16%
2472
6%
760
29%
760
11%
1735
November16th to endNight
17%
820
15%
2842
6%
820
29%
820
9%
2037
December1st to 15thNight
10%
769
10%
2757
2%
769
20%
769
7%
2016
December16th to endNight
13%
800
14%
2880
4%
800
25%
800
7%
2098

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%11%48%6%45%5%5%7%25%
48682
Night
13%9%47%6%35%5%6%8%28%
47985
TransparencyDay
59%310%16%8%1
48365
Night
52%312%19%9%1
47820
SeeingDay
27%16%29%16%7%1
6441
Night
25%20%28%17%7%1
14913

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
9%9%6%10%7%35%5%6%8%26%
1397
16th to endDay
5%9%5%10%8%5%6%6%6%9%26%
1536
February1st to 15thDay
5%10%411%10%5%7%6%5%7%24%
1474
16th to endDay
7%19%6%9%8%45%5%46%23%
1580
March1st to 15thDay
11%12%5%8%7%36%5%47%28%
1799
16th to endDay
10%12%5%9%6%3445%7%30%
2187
April1st to 15thDay
17%15%47%6%2445%6%24%
2173
16th to endDay
17%14%46%5%24446%30%
2340
May1st to 15thDay
22%11%46%43345%5%28%
2432
16th to endDay
22%9%37%6%45%5%5%7%23%
2713
June1st to 15thDay
23%7%36%6%35%45%6%23%
2700
16th to endDay
25%9%46%6%46%45%5%22%
2700
July1st to 15thDay
18%9%47%7%36%6%5%8%21%
2631
16th to endDay
19%8%38%7%46%5%5%7%22%
2654
August1st to 15thDay
19%10%48%7%45%5%6%7%18%
2454
16th to endDay
13%7%38%7%5%6%6%6%8%24%
2441
September1st to 15thDay
18%9%37%5%34346%32%
2106
16th to endDay
15%9%37%43445%7%33%
1980
October1st to 15thDay
19%13%37%6%33446%25%
1866
16th to endDay
19%15%5%7%6%35%45%5%20%
1728
November1st to 15thDay
15%12%410%7%45%35%6%22%
1716
16th to endDay
16%12%5%6%7%36%6%5%7%22%
1446
December1st to 15thDay
16%14%5%8%6%35%447%23%
1285
16th to endDay
13%14%6%8%7%4445%426%
1344
January1st to 15thNight
9%10%48%5%36%6%6%10%26%
2539
16th to endNight
7%9%49%7%46%6%7%9%27%
2688
February1st to 15thNight
48%5%7%8%46%6%7%11%28%
2384
16th to endNight
8%14%6%9%7%36%45%8%25%
1893
March1st to 15thNight
11%10%5%6%5%35%6%7%7%29%
2138
16th to endNight
10%9%5%7%5%35%5%5%8%33%
2035
April1st to 15thNight
16%11%5%8%5%25%45%8%26%
1775
16th to endNight
17%11%45%6%23445%34%
1620
May1st to 15thNight
20%10%5%6%42445%430%
1530
16th to endNight
22%7%35%5%46%35%8%27%
1399
June1st to 15thNight
18%9%36%5%35%45%7%28%
1260
16th to endNight
17%6%47%6%246%5%7%30%
1260
July1st to 15thNight
15%8%25%5%245%6%10%32%
1326
16th to endNight
12%6%25%5%35%5%6%9%35%
1514
August1st to 15thNight
14%5%16%5%46%5%6%10%34%
1494
16th to endNight
13%5%25%4345%6%12%36%
1758
September1st to 15thNight
14%8%35%435%5%5%6%35%
1854
16th to endNight
15%6%26%5%3346%7%37%
1980
October1st to 15thNight
16%8%36%5%445%6%9%29%
2091
16th to endNight
21%10%36%6%445%7%7%22%
2496
November1st to 15thNight
16%9%37%5%26%5%7%9%26%
2472
16th to endNight
13%10%47%6%46%6%6%10%22%
2842
December1st to 15thNight
11%14%5%9%6%35%5%6%8%23%
2757
16th to endNight
12%14%5%8%6%35%5%5%8%23%
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
55%111%17%12%
1398
16th to endDay
53%210%18%13%1
1536
February1st to 15thDay
59%29%15%11%2
1477
16th to endDay
63%2415%10%2
1580
March1st to 15thDay
56%27%14%14%3
1809
16th to endDay
54%27%17%14%3
2187
April1st to 15thDay
59%27%14%11%3
2173
16th to endDay
56%110%15%14%2
2340
May1st to 15thDay
56%211%17%9%1
2432
16th to endDay
61%49%18%6%
2717
June1st to 15thDay
59%411%16%6%
2700
16th to endDay
64%310%13%6%
2700
July1st to 15thDay
60%413%16%4
2477
16th to endDay
63%411%15%5%
2487
August1st to 15thDay
64%414%13%3
2440
16th to endDay
55%5%17%18%3
2441
September1st to 15thDay
53%314%19%8%
2106
16th to endDay
50%314%21%9%
1980
October1st to 15thDay
60%29%19%7%
1866
16th to endDay
66%210%16%4
1728
November1st to 15thDay
62%39%18%5%
1716
16th to endDay
60%39%17%7%
1446
December1st to 15thDay
62%29%18%7%
1285
16th to endDay
61%37%13%11%2
1344
January1st to 15thNight
52%312%18%11%1
2539
16th to endNight
50%310%21%11%1
2688
February1st to 15thNight
48%310%21%13%1
2385
16th to endNight
58%110%15%13%1
1893
March1st to 15thNight
52%48%19%13%2
2151
16th to endNight
49%39%21%13%2
2035
April1st to 15thNight
56%36%18%13%2
1775
16th to endNight
53%29%19%13%2
1620
May1st to 15thNight
56%211%17%10%1
1530
16th to endNight
55%413%18%7%
1401
June1st to 15thNight
54%312%21%6%
1260
16th to endNight
52%417%16%8%
1260
July1st to 15thNight
46%7%19%21%4
1251
16th to endNight
45%7%16%23%7%
1418
August1st to 15thNight
45%7%22%20%3
1484
16th to endNight
41%6%23%24%3
1758
September1st to 15thNight
49%416%22%7%
1854
16th to endNight
46%416%25%6%1
1980
October1st to 15thNight
52%312%21%8%
2091
16th to endNight
60%212%16%7%
2496
November1st to 15thNight
53%413%18%9%
2472
16th to endNight
56%310%19%9%
2842
December1st to 15thNight
59%312%17%7%
2757
16th to endNight
59%210%15%9%1
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
18%30%38%13%
60
16th to endDay
20%14%35%21%7%
64
February1st to 15thDay
21%17%33%16%8%1
118
16th to endDay
25%23%30%12%7%
239
March1st to 15thDay
27%19%34%12%41
270
16th to endDay
20%19%27%20%10%1
288
April1st to 15thDay
31%20%29%11%5%1
270
16th to endDay
31%20%30%9%5%2
270
May1st to 15thDay
32%13%30%13%7%2
288
16th to endDay
29%17%27%16%5%3
426
June1st to 15thDay
32%11%24%21%9%1
495
16th to endDay
29%14%28%20%7%
495
July1st to 15thDay
25%11%34%18%9%
411
16th to endDay
22%11%35%23%6%
326
August1st to 15thDay
24%9%29%23%8%4
313
16th to endDay
22%17%26%18%9%4
332
September1st to 15thDay
24%18%26%19%7%3
315
16th to endDay
22%17%32%14%8%3
314
October1st to 15thDay
29%21%24%16%6%2
300
16th to endDay
35%19%26%11%5%1
288
November1st to 15thDay
32%22%21%14%6%1
280
16th to endDay
35%16%29%12%42
148
December1st to 15thDay
25%26%31%13%11
67
16th to endDay
46%17%28%6%1
64
January1st to 15thNight
24%25%33%12%3
725
16th to endNight
19%24%31%17%5%1
768
February1st to 15thNight
13%26%35%17%5%
704
16th to endNight
23%23%34%12%41
631
March1st to 15thNight
25%24%30%13%4
720
16th to endNight
20%24%30%17%6%1
768
April1st to 15thNight
28%23%27%14%5%
697
16th to endNight
28%17%27%19%6%
540
May1st to 15thNight
31%12%26%19%10%
450
16th to endNight
29%15%28%19%7%
375
June1st to 15thNight
22%12%22%28%10%2
360
16th to endNight
21%10%32%22%11%1
360
July1st to 15thNight
21%13%29%22%10%1
340
16th to endNight
19%9%33%26%10%
376
August1st to 15thNight
19%10%26%26%14%1
413
16th to endNight
19%13%32%21%10%2
612
September1st to 15thNight
21%15%28%24%8%1
720
16th to endNight
21%18%32%16%10%1
717
October1st to 15thNight
24%22%26%17%7%1
720
16th to endNight
34%20%23%14%6%
768
November1st to 15thNight
31%21%24%14%6%1
760
16th to endNight
30%23%23%15%6%1
820
December1st to 15thNight
28%24%26%15%4
769
16th to endNight
32%19%26%14%5%1
800
Page generated at 2017-12-05 10:19:04. Version ac04

Copyright 2017 A. Danko


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