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 2017-12-20.

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
33%
15001
13%
48041
9%
14970
38%
14970
17%
34595

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
22%
720
9%
2506
6%
716
26%
716
9%
1975
January16th to endNight
24%
768
10%
2688
6%
768
30%
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
34%
720
15%
1642
March16th to endNight
34%
768
18%
2000
10%
768
39%
768
23%
1435
April1st to 15thNight
27%
718
15%
1796
5%
718
33%
718
19%
1368
April16th to endNight
29%
612
16%
1692
5%
612
37%
612
21%
1199
May1st to 15thNight
32%
402
16%
1482
14%
402
41%
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
45%
360
8%
1440
11%
360
49%
360
17%
942
July1st to 15thNight
53%
340
11%
1360
17%
340
58%
340
23%
809
July16th to endNight
55%
376
12%
1418
16%
354
58%
354
23%
851
August1st to 15thNight
55%
368
14%
1439
16%
366
58%
366
20%
912
August16th to endNight
56%
747
18%
1893
11%
747
58%
747
34%
1240
September1st to 15thNight
49%
720
14%
1800
7%
720
50%
720
28%
1260
September16th to endNight
50%
717
22%
1977
15%
717
54%
717
31%
1252
October1st to 15thNight
35%
720
18%
2109
11%
720
44%
720
22%
1450
October16th to endNight
28%
768
12%
2472
8%
768
34%
768
15%
1820
November1st to 15thNight
26%
760
17%
2472
12%
760
34%
760
16%
1757
November16th to endNight
24%
780
13%
2707
8%
780
31%
780
12%
2024
December1st to 15thNight
18%
780
8%
2730
4%
780
24%
780
9%
2146
December16th to endNight
15%
788
10%
2755
3%
788
24%
788
9%
2193

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%
48804
Night
19%9%46%5%34446%32%
48210
Cloud CoverDay
18%8%36%5%3445%6%33%
48814
Night
19%9%46%5%34446%32%
48215
TransparencyDay
50%6%12%19%9%1
48491
Night
53%5%10%18%9%1
48041
SeeingDay
22%6%25%26%14%4
5866
Night
23%6%28%29%10%
15002

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%5%9%34%
2497
16th to endDay
9%4244345%6%7%47%
2308
September1st to 15thDay
16%5%25%32445%7%43%
2160
16th to endDay
13%414423346%49%
1983
October1st to 15thDay
19%6%36%5%34447%34%
1848
16th to endDay
23%8%36%6%3444429%
1752
November1st to 15thDay
17%9%35%5%345%5%6%31%
1716
16th to endDay
22%9%37%5%25%43430%
1579
December1st to 15thDay
25%11%5%7%5%3445%5%21%
1560
16th to endDay
26%15%46%5%23336%21%
1568
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%
1449
16th to endNight
12%41442445%8%45%
1893
September1st to 15thNight
16%5%25%5%235%46%41%
1800
16th to endNight
17%423322347%48%
1977
October1st to 15thNight
17%6%26%5%24446%39%
2109
16th to endNight
25%8%36%5%33345%31%
2472
November1st to 15thNight
21%8%26%5%34445%33%
2472
16th to endNight
23%12%47%5%3433428%
2707
December1st to 15thNight
23%13%5%8%6%23335%23%
2730
16th to endNight
24%16%5%8%5%2333422%
2755

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%
2497
16th to endDay
9%4134345%6%8%46%
2308
September1st to 15thDay
15%5%25%423448%42%
2160
16th to endDay
13%413433346%49%
1983
October1st to 15thDay
19%6%36%5%34446%34%
1848
16th to endDay
23%9%36%6%34445%29%
1752
November1st to 15thDay
17%10%35%5%35%46%6%31%
1716
16th to endDay
23%9%46%5%345%4429%
1579
December1st to 15thDay
25%12%5%8%5%2435%5%21%
1560
16th to endDay
26%15%5%6%42433422%
1568
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%6%25%5%35%5%6%8%37%
1449
16th to endNight
12%425%43345%8%45%
1893
September1st to 15thNight
16%5%25%5%245%45%41%
1800
16th to endNight
17%423223247%48%
1977
October1st to 15thNight
18%6%35%424445%39%
2109
16th to endNight
26%8%36%433345%31%
2472
November1st to 15thNight
22%8%26%5%34445%32%
2472
16th to endNight
24%11%47%43433428%
2707
December1st to 15thNight
23%13%5%8%6%24335%22%
2730
16th to endNight
23%16%6%8%5%2333422%
2755

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%
2483
16th to endDay
32%8%18%27%12%
2308
September1st to 15thDay
40%6%15%26%11%
2160
16th to endDay
35%5%13%32%13%
1983
October1st to 15thDay
50%6%12%22%8%
1848
16th to endDay
57%5%13%16%6%
1752
November1st to 15thDay
51%6%13%18%8%
1716
16th to endDay
55%7%11%15%8%
1579
December1st to 15thDay
64%6%12%12%4
1560
16th to endDay
66%6%10%9%7%
1568
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
42%8%16%22%10%
1439
16th to endNight
36%6%16%28%11%
1893
September1st to 15thNight
42%6%11%24%13%
1800
16th to endNight
36%6%11%30%14%
1977
October1st to 15thNight
46%6%10%25%11%
2109
16th to endNight
55%5%11%19%7%
2472
November1st to 15thNight
53%412%19%8%1
2472
16th to endNight
59%410%17%6%
2707
December1st to 15thNight
64%5%11%14%4
2730
16th to endNight
66%49%11%6%
2755

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%319%30%23%8%
313
16th to endDay
10%420%28%20%15%
332
September1st to 15thDay
16%320%27%19%12%
315
16th to endDay
14%5%25%21%21%11%
314
October1st to 15thDay
22%7%24%26%14%3
315
16th to endDay
28%8%26%23%11%
294
November1st to 15thDay
23%7%30%21%14%1
280
16th to endDay
31%11%24%23%7%
109
December1st to 15thDay
26%8%27%23%10%3
90
16th to endDay
41%15%29%13%
72
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%42%22%2
368
16th to endNight
14%219%38%23%2
747
September1st to 15thNight
20%319%40%15%1
720
16th to endNight
17%422%31%19%3
717
October1st to 15thNight
21%5%30%28%12%1
720
16th to endNight
30%8%27%24%8%
768
November1st to 15thNight
26%7%30%24%10%
760
16th to endNight
29%9%29%20%10%
780
December1st to 15thNight
29%8%31%24%5%
780
16th to endNight
31%7%31%21%6%1
788
Page generated at 2017-12-21 07:04:53. Version ac04

Copyright 2017 A. Danko


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