Parc de la FrayŤre
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Parc de la FrayŤre clear sky chart from 2005-11-05 to 2017-08-12.

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
32%
14485
13%
46474
9%
14454
38%
14454
16%
33539

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
21%
720
9%
2506
6%
716
25%
716
9%
1975
January16th to endNight
25%
768
10%
2688
6%
768
31%
768
11%
2030
February1st to 15thNight
21%
703
8%
2315
5%
701
27%
701
10%
1840
February16th to endNight
26%
631
12%
1893
6%
631
33%
631
14%
1446
March1st to 15thNight
28%
720
13%
2160
9%
720
33%
720
15%
1642
March16th to endNight
34%
768
18%
2000
10%
768
40%
768
23%
1435
April1st to 15thNight
28%
718
15%
1796
5%
718
33%
718
19%
1368
April16th to endNight
30%
612
16%
1692
5%
612
37%
612
21%
1199
May1st to 15thNight
33%
402
16%
1482
14%
402
42%
402
17%
1002
May16th to endNight
33%
375
12%
1497
11%
374
41%
374
17%
988
June1st to 15thNight
37%
360
8%
1440
7%
360
43%
360
13%
1014
June16th to endNight
46%
360
8%
1440
11%
360
50%
360
17%
942
July1st to 15thNight
53%
340
12%
1360
17%
340
58%
340
23%
809
July16th to endNight
55%
376
12%
1418
16%
354
58%
354
23%
851
August1st to 15thNight
57%
359
14%
1408
16%
357
59%
357
20%
887
August16th to endNight
56%
684
17%
1734
11%
684
57%
684
33%
1142
September1st to 15thNight
49%
660
14%
1650
8%
660
50%
660
28%
1163
September16th to endNight
48%
657
20%
1812
13%
657
52%
657
30%
1165
October1st to 15thNight
34%
660
19%
1933
11%
660
43%
660
21%
1343
October16th to endNight
28%
704
11%
2266
7%
704
34%
704
15%
1686
November1st to 15thNight
27%
700
17%
2277
11%
700
35%
700
16%
1626
November16th to endNight
24%
720
13%
2499
9%
720
31%
720
12%
1866
December1st to 15thNight
19%
720
8%
2520
4%
720
24%
720
10%
1986
December16th to endNight
15%
768
10%
2688
4%
768
23%
768
9%
2134

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%8%36%5%3445%6%33%
47504
Night
19%9%46%5%34445%32%
46643
Cloud CoverDay
18%8%36%5%3445%6%33%
47514
Night
19%9%46%5%34445%31%
46648
TransparencyDay
50%6%12%19%9%1
47191
Night
53%5%10%18%9%1
46474
SeeingDay
22%6%25%26%14%4
5442
Night
23%6%28%29%10%
14486

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
22%13%5%8%8%4433421%
1432
16th to endDay
14%13%38%6%35%5%46%28%
1536
February1st to 15thDay
14%14%5%10%6%35%445%24%
1543
16th to endDay
17%12%5%7%7%2445%428%
1580
March1st to 15thDay
17%10%47%6%45%445%28%
1790
16th to endDay
18%8%45%434335%37%
2223
April1st to 15thDay
22%9%27%5%34335%32%
2152
16th to endDay
19%7%26%424445%38%
2267
May1st to 15thDay
21%6%35%5%345%5%5%33%
2478
16th to endDay
20%5%35%5%345%5%7%34%
2618
June1st to 15thDay
23%5%245%345%5%8%31%
2520
16th to endDay
17%6%25%5%35%46%8%31%
2520
July1st to 15thDay
12%425%5%36%5%6%9%37%
2520
16th to endDay
12%425%5%35%5%8%9%36%
2654
August1st to 15thDay
12%5%26%7%35%5%6%9%34%
2443
16th to endDay
10%4234245%6%7%46%
2115
September1st to 15thDay
16%5%25%32445%7%42%
1980
16th to endDay
14%414424346%47%
1818
October1st to 15thDay
20%6%36%5%3445%7%33%
1694
16th to endDay
24%9%35%6%3444428%
1606
November1st to 15thDay
17%10%36%43445%6%32%
1581
16th to endDay
23%9%37%5%25%43431%
1458
December1st to 15thDay
27%11%5%7%5%34446%20%
1440
16th to endDay
27%14%46%5%23336%21%
1536
January1st to 15thNight
18%15%6%9%6%34445%22%
2506
16th to endNight
13%13%6%7%7%35%45%5%25%
2688
February1st to 15thNight
14%12%7%11%7%46%34422%
2313
16th to endNight
17%12%5%8%6%4444428%
1893
March1st to 15thNight
21%11%46%5%3434429%
2147
16th to endNight
17%10%35%5%24335%38%
2000
April1st to 15thNight
26%8%45%5%23335%31%
1796
16th to endNight
23%7%25%5%23345%36%
1692
May1st to 15thNight
20%7%36%5%24445%36%
1482
16th to endNight
21%6%25%5%2445%7%34%
1495
June1st to 15thNight
26%6%35%42446%6%29%
1440
16th to endNight
16%5%26%4345%6%8%35%
1440
July1st to 15thNight
11%425%446%46%11%39%
1440
16th to endNight
11%3344346%6%9%41%
1514
August1st to 15thNight
12%5%26%5%345%6%8%38%
1418
16th to endNight
13%41442445%7%45%
1734
September1st to 15thNight
17%5%35%5%235%46%40%
1650
16th to endNight
18%423322346%47%
1812
October1st to 15thNight
18%7%26%424446%38%
1933
16th to endNight
26%8%36%5%3333430%
2266
November1st to 15thNight
21%8%36%6%34445%32%
2277
16th to endNight
23%11%47%434335%28%
2499
December1st to 15thNight
24%13%5%8%6%23336%23%
2520
16th to endNight
24%16%5%7%5%2333422%
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
22%14%5%8%7%3443322%
1432
16th to endDay
14%13%47%6%35%445%28%
1536
February1st to 15thDay
14%14%5%9%6%46%435%23%
1543
16th to endDay
18%13%5%8%6%3335%427%
1580
March1st to 15thDay
18%10%48%6%345%35%27%
1800
16th to endDay
17%8%47%5%23445%36%
2223
April1st to 15thDay
23%9%36%5%3433432%
2152
16th to endDay
20%7%35%5%34345%38%
2267
May1st to 15thDay
20%6%35%6%3435%7%32%
2478
16th to endDay
20%6%26%5%3445%8%33%
2618
June1st to 15thDay
22%6%25%43445%7%31%
2520
16th to endDay
17%6%36%435%5%6%8%31%
2520
July1st to 15thDay
12%436%445%6%6%8%37%
2520
16th to endDay
12%425%5%36%5%7%9%36%
2654
August1st to 15thDay
13%5%26%6%45%5%6%8%34%
2443
16th to endDay
9%5%134345%6%8%45%
2115
September1st to 15thDay
15%5%25%423448%41%
1980
16th to endDay
14%5%14433346%47%
1818
October1st to 15thDay
20%6%36%5%2445%6%32%
1694
16th to endDay
23%10%35%5%34445%28%
1606
November1st to 15thDay
16%10%45%5%3446%6%31%
1581
16th to endDay
23%9%36%42444430%
1458
December1st to 15thDay
26%12%5%8%5%2435%5%20%
1440
16th to endDay
26%15%5%6%5%2433422%
1536
January1st to 15thNight
19%15%5%9%6%24445%21%
2506
16th to endNight
13%13%6%8%6%45%5%5%5%25%
2688
February1st to 15thNight
14%13%7%11%8%36%44422%
2306
16th to endNight
17%12%5%8%6%35%44427%
1893
March1st to 15thNight
21%12%46%6%2434429%
2160
16th to endNight
17%10%36%42433438%
1999
April1st to 15thNight
26%8%445%24335%30%
1796
16th to endNight
23%7%25%424345%35%
1692
May1st to 15thNight
20%7%36%5%3335%5%35%
1482
16th to endNight
20%7%26%424448%33%
1495
June1st to 15thNight
25%7%35%33445%7%28%
1440
16th to endNight
16%5%36%425%5%6%8%35%
1440
July1st to 15thNight
11%415%5%35%5%6%10%39%
1440
16th to endNight
11%415%5%36%5%7%9%40%
1514
August1st to 15thNight
13%5%25%5%35%5%6%9%37%
1418
16th to endNight
13%425%43346%8%44%
1734
September1st to 15thNight
17%5%26%5%24445%41%
1650
16th to endNight
18%423323247%47%
1812
October1st to 15thNight
19%6%35%424445%38%
1933
16th to endNight
26%8%36%43334430%
2266
November1st to 15thNight
21%8%36%6%34445%31%
2277
16th to endNight
24%11%47%43443428%
2499
December1st to 15thNight
24%13%5%8%5%24336%22%
2520
16th to endNight
23%16%6%8%5%2333422%
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
67%5%9%12%5%
1433
16th to endDay
57%6%12%15%7%
1536
February1st to 15thDay
62%410%17%4
1545
16th to endDay
59%49%15%9%1
1580
March1st to 15thDay
58%5%10%16%8%1
1800
16th to endDay
48%410%18%13%3
2223
April1st to 15thDay
55%47%19%11%2
2152
16th to endDay
49%49%19%13%3
2267
May1st to 15thDay
51%5%10%18%12%1
2478
16th to endDay
48%6%12%18%11%1
2622
June1st to 15thDay
50%7%11%18%10%1
2520
16th to endDay
49%7%11%22%7%1
2520
July1st to 15thDay
40%8%14%25%11%
2371
16th to endDay
41%8%19%22%7%
2487
August1st to 15thDay
45%8%17%21%6%
2429
16th to endDay
33%8%19%26%12%
2115
September1st to 15thDay
40%5%15%25%11%
1980
16th to endDay
37%5%12%31%12%
1818
October1st to 15thDay
50%6%12%21%8%
1694
16th to endDay
58%5%12%16%6%
1606
November1st to 15thDay
51%7%12%18%9%
1581
16th to endDay
55%7%11%16%8%
1458
December1st to 15thDay
64%6%12%12%3
1440
16th to endDay
66%6%10%9%7%
1536
January1st to 15thNight
64%5%10%14%4
2506
16th to endNight
59%6%10%15%7%
2688
February1st to 15thNight
64%5%9%14%5%
2315
16th to endNight
59%5%10%14%10%
1893
March1st to 15thNight
58%5%8%16%9%1
2160
16th to endNight
50%49%17%15%3
2000
April1st to 15thNight
57%35%18%14%1
1796
16th to endNight
50%48%18%14%4
1692
May1st to 15thNight
51%48%17%13%4
1482
16th to endNight
49%5%10%20%12%2
1497
June1st to 15thNight
54%6%9%18%10%
1440
16th to endNight
44%9%11%19%14%1
1440
July1st to 15thNight
37%7%14%25%13%
1360
16th to endNight
37%8%17%22%13%
1418
August1st to 15thNight
41%8%16%22%10%
1408
16th to endNight
36%6%16%28%11%
1734
September1st to 15thNight
43%6%11%24%12%
1650
16th to endNight
37%6%11%29%14%
1812
October1st to 15thNight
47%6%10%24%11%
1933
16th to endNight
57%5%11%18%7%
2266
November1st to 15thNight
53%412%18%8%1
2277
16th to endNight
59%410%17%7%
2499
December1st to 15thNight
64%5%11%14%3
2520
16th to endNight
66%49%11%6%
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
21%11%21%30%15%
60
16th to endDay
34%6%32%15%9%1
64
February1st to 15thDay
29%10%31%24%3
91
16th to endDay
27%8%26%29%6%
239
March1st to 15thDay
25%8%29%27%8%
270
16th to endDay
23%330%27%12%2
288
April1st to 15thDay
27%11%28%19%10%2
270
16th to endDay
22%10%27%24%12%3
270
May1st to 15thDay
27%6%29%18%14%4
288
16th to endDay
23%7%29%21%15%2
331
June1st to 15thDay
26%8%20%30%11%2
315
16th to endDay
18%7%24%30%16%2
315
July1st to 15thDay
15%424%29%19%6%
305
16th to endDay
15%217%36%22%5%
326
August1st to 15thDay
15%318%28%24%9%
297
16th to endDay
10%418%29%21%15%
268
September1st to 15thDay
16%318%29%19%12%
255
16th to endDay
17%7%28%20%16%10%
254
October1st to 15thDay
23%7%24%26%14%3
255
16th to endDay
31%6%24%24%12%
244
November1st to 15thDay
22%7%32%22%14%1
235
16th to endDay
34%8%19%28%7%1
78
December1st to 15thDay
30%5%30%25%6%3
60
16th to endDay
40%17%31%10%
64
January1st to 15thNight
25%11%30%26%6%
720
16th to endNight
21%8%33%28%7%1
768
February1st to 15thNight
20%7%34%28%7%
704
16th to endNight
22%6%33%30%6%
631
March1st to 15thNight
28%6%28%29%6%
720
16th to endNight
21%431%31%9%
768
April1st to 15thNight
29%10%25%29%5%
718
16th to endNight
26%9%28%25%8%
612
May1st to 15thNight
24%5%30%28%10%
402
16th to endNight
22%6%30%31%7%
375
June1st to 15thNight
27%421%34%11%
360
16th to endNight
17%328%37%12%
360
July1st to 15thNight
11%326%38%19%
340
16th to endNight
13%121%45%17%
376
August1st to 15thNight
13%216%41%23%3
359
16th to endNight
14%219%37%24%1
684
September1st to 15thNight
20%318%40%15%1
660
16th to endNight
19%424%31%17%2
657
October1st to 15thNight
22%5%31%28%11%1
660
16th to endNight
31%8%27%24%8%
704
November1st to 15thNight
26%6%30%24%11%
700
16th to endNight
29%9%29%20%10%
720
December1st to 15thNight
30%7%31%24%5%
720
16th to endNight
31%7%32%20%5%1
768
Page generated at 2017-08-13 14:16:54. Version ac04

Copyright 2017 A. Danko


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