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 2017-03-24.

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%
14111
13%
45341
4%
14081
29%
14081
12%
31925

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%
740
19%
1964
5%
740
28%
740
16%
1386
April1st to 15thNight
16%
639
17%
1627
3%
639
26%
639
13%
1215
April16th to endNight
21%
495
16%
1485
5%
495
30%
495
15%
1029
May1st to 15thNight
24%
413
11%
1403
7%
413
33%
413
14%
971
May16th to endNight
21%
342
9%
1281
4%
342
32%
342
12%
917
June1st to 15thNight
31%
330
7%
1155
4%
330
35%
330
13%
831
June16th to endNight
26%
330
5%
1155
3%
330
29%
330
15%
802
July1st to 15thNight
29%
310
7%
1140
5%
310
34%
310
16%
766
July16th to endNight
28%
348
8%
1306
6%
326
36%
326
14%
864
August1st to 15thNight
34%
378
11%
1359
8%
376
40%
376
17%
901
August16th to endNight
29%
561
12%
1611
4%
561
35%
561
21%
1058
September1st to 15thNight
28%
660
10%
1699
4%
660
31%
660
20%
1223
September16th to endNight
20%
657
16%
1815
6%
657
28%
657
20%
1246
October1st to 15thNight
18%
660
15%
1917
5%
660
28%
660
14%
1386
October16th to endNight
15%
704
10%
2288
5%
704
22%
704
8%
1722
November1st to 15thNight
17%
700
16%
2277
6%
700
29%
700
11%
1594
November16th to endNight
18%
747
14%
2623
6%
747
29%
747
9%
1897
December1st to 15thNight
10%
750
10%
2700
2%
750
20%
750
7%
1975
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%35%5%5%7%25%
45603
Night
13%9%47%6%35%5%6%8%28%
45506
TransparencyDay
59%310%16%8%1
45286
Night
53%312%19%9%1
45341
SeeingDay
27%16%29%17%7%2
5453
Night
25%20%29%17%6%1
14113

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%6%30%
2104
April1st to 15thDay
16%14%37%6%3445%6%25%
1991
16th to endDay
17%13%45%5%24446%32%
2145
May1st to 15thDay
20%10%46%43446%6%30%
2228
16th to endDay
22%9%37%6%35%5%5%7%23%
2481
June1st to 15thDay
24%8%36%7%36%45%6%21%
2475
16th to endDay
25%9%46%7%45%35%5%22%
2475
July1st to 15thDay
19%9%48%7%36%6%6%8%20%
2412
16th to endDay
20%8%48%7%46%5%47%22%
2458
August1st to 15thDay
20%10%48%7%45%5%6%8%17%
2250
16th to endDay
14%7%38%7%5%6%7%6%9%24%
2237
September1st to 15thDay
19%9%36%5%34447%31%
1931
16th to endDay
16%9%37%43345%7%33%
1815
October1st to 15thDay
20%14%37%6%33446%24%
1711
16th to endDay
20%15%5%8%6%3445%5%20%
1584
November1st to 15thDay
15%13%411%7%45%35%6%22%
1581
16th to endDay
16%12%5%5%7%36%5%5%6%23%
1335
December1st to 15thDay
16%14%5%8%6%35%446%23%
1260
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%
1964
April1st to 15thNight
16%12%5%7%5%25%45%8%27%
1627
16th to endNight
16%10%35%6%245%45%35%
1485
May1st to 15thNight
19%8%46%5%25%45%5%32%
1403
16th to endNight
22%7%345%46%35%8%27%
1279
June1st to 15thNight
20%9%37%5%35%35%7%26%
1155
16th to endNight
18%6%46%6%246%5%7%31%
1155
July1st to 15thNight
15%8%25%5%245%6%10%32%
1215
16th to endNight
13%6%35%5%35%5%6%9%34%
1402
August1st to 15thNight
15%6%15%5%45%5%6%9%34%
1369
16th to endNight
13%5%15%5%346%6%11%35%
1611
September1st to 15thNight
14%8%45%435%5%5%7%35%
1699
16th to endNight
16%7%26%5%3346%7%37%
1815
October1st to 15thNight
16%9%36%5%445%6%8%29%
1917
16th to endNight
21%10%36%6%445%7%7%21%
2288
November1st to 15thNight
16%9%36%5%26%5%7%9%26%
2277
16th to endNight
14%10%47%6%46%6%6%10%22%
2623
December1st to 15thNight
11%14%5%8%6%35%5%6%8%23%
2700
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
2104
April1st to 15thDay
59%17%15%11%4
1991
16th to endDay
54%110%15%15%2
2145
May1st to 15thDay
54%311%18%10%1
2228
16th to endDay
60%49%18%6%
2485
June1st to 15thDay
61%5%11%15%6%
2475
16th to endDay
64%311%14%6%
2475
July1st to 15thDay
61%414%15%4
2258
16th to endDay
64%311%14%5%
2291
August1st to 15thDay
65%414%12%2
2236
16th to endDay
54%5%17%18%3
2237
September1st to 15thDay
53%314%18%9%
1931
16th to endDay
51%313%21%8%
1815
October1st to 15thDay
62%29%18%7%
1711
16th to endDay
67%29%16%4
1584
November1st to 15thDay
62%38%18%5%
1581
16th to endDay
60%39%18%6%
1335
December1st to 15thDay
62%29%18%7%
1260
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
1964
April1st to 15thNight
55%26%18%14%2
1627
16th to endNight
51%29%18%14%2
1485
May1st to 15thNight
53%212%18%10%1
1403
16th to endNight
55%413%18%6%
1281
June1st to 15thNight
57%312%19%6%
1155
16th to endNight
52%416%16%9%
1155
July1st to 15thNight
47%6%20%20%4
1140
16th to endNight
46%7%16%22%6%
1306
August1st to 15thNight
46%6%23%20%3
1359
16th to endNight
42%6%23%23%3
1611
September1st to 15thNight
49%416%21%7%
1699
16th to endNight
47%315%25%6%1
1815
October1st to 15thNight
53%312%20%8%
1917
16th to endNight
61%211%16%7%
2288
November1st to 15thNight
52%414%19%8%
2277
16th to endNight
58%310%18%8%
2623
December1st to 15thNight
59%312%17%7%
2700
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
19%18%28%20%11%1
260
April1st to 15thDay
29%21%28%13%6%1
210
16th to endDay
30%18%32%10%5%3
210
May1st to 15thDay
25%13%33%15%9%2
228
16th to endDay
29%17%28%16%43
354
June1st to 15thDay
32%10%24%21%8%1
420
16th to endDay
27%13%29%21%7%
420
July1st to 15thDay
25%11%34%17%10%
342
16th to endDay
25%9%34%24%5%
270
August1st to 15thDay
26%9%26%22%11%4
253
16th to endDay
22%16%28%20%8%3
268
September1st to 15thDay
23%17%26%18%8%4
255
16th to endDay
26%18%29%13%8%3
254
October1st to 15thDay
29%21%23%16%6%2
245
16th to endDay
35%18%29%10%5%1
240
November1st to 15thDay
30%22%23%15%5%2
235
16th to endDay
37%13%28%12%6%2
114
December1st to 15thDay
28%28%33%8%1
60
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
19%24%30%17%7%1
740
April1st to 15thNight
28%23%27%13%5%
639
16th to endNight
27%18%27%18%6%
495
May1st to 15thNight
28%12%27%20%9%
413
16th to endNight
28%16%28%19%7%
343
June1st to 15thNight
23%12%22%28%10%2
330
16th to endNight
21%11%31%23%11%1
330
July1st to 15thNight
21%13%31%21%10%1
310
16th to endNight
20%9%34%26%9%
348
August1st to 15thNight
21%11%26%24%15%1
378
16th to endNight
19%13%33%21%10%1
561
September1st to 15thNight
21%15%27%24%8%2
660
16th to endNight
22%19%33%15%8%1
657
October1st to 15thNight
25%22%26%17%6%1
660
16th to endNight
34%20%23%13%6%
704
November1st to 15thNight
30%22%25%14%5%1
700
16th to endNight
30%21%23%15%6%1
747
December1st to 15thNight
29%24%26%15%4
750
16th to endNight
32%19%26%14%5%1
800
Page generated at 2017-03-25 12:39:46. Version ac04

Copyright 2017 A. Danko


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