ZEC des Nymphes
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the ZEC des Nymphes clear sky chart from 2005-11-05 to

2017-09-12
.

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
26%
14551
14%
46783
7%
14519
35%
14519
16%
32931

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
15%
720
11%
2506
3%
716
25%
716
9%
1889
January16th to endNight
18%
768
12%
2688
5%
768
28%
768
11%
1981
February1st to 15thNight
19%
704
11%
2335
4%
701
29%
701
11%
1738
February16th to endNight
20%
631
15%
1896
5%
631
33%
631
13%
1390
March1st to 15thNight
19%
720
14%
2159
7%
720
27%
720
12%
1621
March16th to endNight
26%
768
21%
2001
7%
768
35%
768
19%
1401
April1st to 15thNight
23%
718
17%
1796
5%
718
29%
718
17%
1342
April16th to endNight
24%
606
17%
1686
4%
606
34%
606
19%
1162
May1st to 15thNight
27%
381
15%
1461
11%
381
37%
381
16%
996
May16th to endNight
25%
375
13%
1497
9%
374
39%
374
16%
988
June1st to 15thNight
28%
360
7%
1440
5%
360
35%
360
13%
988
June16th to endNight
36%
360
7%
1440
7%
360
41%
360
15%
968
July1st to 15thNight
45%
340
10%
1360
14%
340
49%
340
23%
804
July16th to endNight
44%
376
12%
1418
12%
354
49%
354
21%
866
August1st to 15thNight
53%
359
13%
1430
14%
357
58%
357
20%
886
August16th to endNight
46%
729
19%
1875
10%
729
51%
729
32%
1202
September1st to 15thNight
40%
707
14%
1768
6%
707
43%
707
30%
1211
September16th to endNight
39%
657
21%
1809
12%
657
46%
657
29%
1150
October1st to 15thNight
27%
660
20%
1941
9%
660
39%
660
18%
1319
October16th to endNight
22%
704
12%
2269
6%
704
31%
704
16%
1629
November1st to 15thNight
26%
700
18%
2280
11%
700
37%
700
16%
1595
November16th to endNight
20%
720
14%
2520
7%
720
29%
720
10%
1845
December1st to 15thNight
18%
720
11%
2520
5%
720
27%
720
10%
1880
December16th to endNight
13%
768
12%
2688
3%
768
24%
768
7%
2080

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%9%47%6%35%45%6%28%
47890
Night
17%9%46%5%34446%32%
46953
TransparencyDay
53%5%10%18%9%1
47577
Night
51%5%10%20%10%1
46784
SeeingDay
24%14%30%19%8%2
5530
Night
23%12%28%24%8%
14551

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
17%14%6%8%7%45%345%23%
1432
16th to endDay
11%13%7%9%7%35%5%46%25%
1536
February1st to 15thDay
10%15%5%8%9%47%34425%
1524
16th to endDay
14%16%6%9%5%35%435%25%
1577
March1st to 15thDay
15%12%5%9%7%44345%27%
1790
16th to endDay
14%10%47%434446%35%
2223
April1st to 15thDay
21%11%36%5%24335%31%
2152
16th to endDay
20%8%46%5%23446%33%
2274
May1st to 15thDay
22%8%37%6%34446%28%
2501
16th to endDay
22%7%46%6%35%445%29%
2618
June1st to 15thDay
22%7%26%5%35%5%5%7%26%
2520
16th to endDay
21%8%35%7%45%5%5%8%24%
2520
July1st to 15thDay
15%6%36%7%45%5%6%7%29%
2520
16th to endDay
13%6%38%7%35%5%7%9%28%
2654
August1st to 15thDay
17%6%36%6%47%5%8%8%24%
2514
16th to endDay
11%5%25%6%35%5%7%9%35%
2320
September1st to 15thDay
18%5%26%5%345%46%35%
2112
16th to endDay
19%6%24424346%41%
1821
October1st to 15thDay
24%9%35%5%3445%6%27%
1687
16th to endDay
24%12%37%5%3435%5%22%
1602
November1st to 15thDay
18%10%46%6%345%5%6%28%
1577
16th to endDay
21%13%46%424335%29%
1440
December1st to 15thDay
25%14%47%5%33445%22%
1440
16th to endDay
22%15%5%9%5%34335%22%
1536
January1st to 15thNight
16%15%6%8%5%3445%7%22%
2506
16th to endNight
10%12%7%9%8%45%445%27%
2688
February1st to 15thNight
9%13%6%10%7%5%5%5%5%6%26%
2333
16th to endNight
14%10%5%7%6%34446%30%
1896
March1st to 15thNight
17%12%47%5%35%45%5%28%
2147
16th to endNight
11%10%46%5%2435%6%39%
2001
April1st to 15thNight
21%9%36%5%3434432%
1796
16th to endNight
19%7%25%425%45%6%36%
1686
May1st to 15thNight
19%8%26%6%34336%34%
1461
16th to endNight
23%5%25%423448%34%
1495
June1st to 15thNight
21%8%445%3445%6%31%
1440
16th to endNight
17%7%345%35%5%6%7%31%
1440
July1st to 15thNight
12%425%335%5%5%9%42%
1440
16th to endNight
12%5%25%5%245%5%7%44%
1514
August1st to 15thNight
12%5%25%5%35%5%6%8%38%
1440
16th to endNight
12%5%2442345%8%46%
1875
September1st to 15thNight
15%5%25%42445%7%41%
1768
16th to endNight
18%5%23313345%48%
1809
October1st to 15thNight
19%8%25%5%2445%6%36%
1941
16th to endNight
24%7%36%5%23447%28%
2269
November1st to 15thNight
19%8%36%5%35%446%33%
2280
16th to endNight
21%13%46%5%22346%29%
2520
December1st to 15thNight
20%15%5%7%433346%25%
2520
16th to endNight
20%16%5%8%5%35%345%21%
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
62%6%8%14%7%
1433
16th to endDay
58%47%18%9%1
1536
February1st to 15thDay
61%38%18%7%
1526
16th to endDay
61%36%16%9%1
1577
March1st to 15thDay
58%38%14%12%1
1800
16th to endDay
50%38%17%16%4
2223
April1st to 15thDay
54%37%18%11%4
2152
16th to endDay
50%5%7%18%14%3
2274
May1st to 15thDay
55%47%17%11%2
2501
16th to endDay
55%5%9%16%10%1
2622
June1st to 15thDay
53%7%10%17%9%1
2520
16th to endDay
56%6%9%18%8%
2520
July1st to 15thDay
47%7%13%21%9%
2371
16th to endDay
49%8%14%19%8%
2487
August1st to 15thDay
51%9%14%19%4
2500
16th to endDay
40%8%15%24%9%
2320
September1st to 15thDay
46%5%14%23%10%
2112
16th to endDay
42%5%10%29%10%
1821
October1st to 15thDay
53%5%9%21%8%
1687
16th to endDay
61%410%16%6%
1602
November1st to 15thDay
53%5%11%18%9%
1577
16th to endDay
57%49%19%8%
1440
December1st to 15thDay
63%410%17%5%
1440
16th to endDay
63%47%12%11%
1536
January1st to 15thNight
60%49%17%7%
2506
16th to endNight
57%5%9%16%9%1
2688
February1st to 15thNight
58%5%9%18%7%
2335
16th to endNight
54%5%8%17%12%1
1896
March1st to 15thNight
57%5%7%17%10%1
2160
16th to endNight
46%5%7%20%16%3
2001
April1st to 15thNight
53%4420%14%2
1796
16th to endNight
46%5%8%20%14%3
1686
May1st to 15thNight
51%39%17%13%3
1461
16th to endNight
48%5%11%20%12%1
1497
June1st to 15thNight
51%6%11%19%9%
1440
16th to endNight
47%8%11%19%12%
1440
July1st to 15thNight
37%7%17%23%12%1
1360
16th to endNight
39%8%16%24%11%
1418
August1st to 15thNight
40%8%18%25%6%
1430
16th to endNight
35%5%15%31%10%
1875
September1st to 15thNight
41%5%15%25%12%
1768
16th to endNight
37%412%33%11%
1809
October1st to 15thNight
46%5%10%24%12%
1941
16th to endNight
54%312%21%7%
2269
November1st to 15thNight
51%5%11%20%9%1
2280
16th to endNight
58%49%19%7%
2520
December1st to 15thNight
59%411%18%5%
2520
16th to endNight
64%47%14%7%1
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
26%13%35%20%5%
60
16th to endDay
21%23%32%12%6%3
64
February1st to 15thDay
30%24%32%9%2
81
16th to endDay
24%22%27%19%5%
236
March1st to 15thDay
25%18%29%21%4
270
16th to endDay
24%18%27%17%9%3
288
April1st to 15thDay
31%17%29%12%7%1
270
16th to endDay
28%18%29%12%8%2
270
May1st to 15thDay
33%15%27%14%6%2
288
16th to endDay
25%18%34%13%5%1
331
June1st to 15thDay
28%13%35%14%6%1
315
16th to endDay
23%13%34%19%7%
315
July1st to 15thDay
16%11%35%25%7%2
305
16th to endDay
15%6%35%28%12%2
326
August1st to 15thDay
17%7%30%28%12%3
313
16th to endDay
15%8%28%25%14%7%
332
September1st to 15thDay
20%9%28%23%11%6%
299
16th to endDay
21%12%28%15%13%8%
254
October1st to 15thDay
27%13%24%21%10%2
255
16th to endDay
31%15%26%18%8%
243
November1st to 15thDay
20%16%26%24%9%1
231
16th to endDay
38%15%26%15%5%
60
December1st to 15thDay
26%21%30%18%11
60
16th to endDay
45%17%29%7%
64
January1st to 15thNight
24%15%34%19%5%
720
16th to endNight
20%16%33%22%6%
768
February1st to 15thNight
16%16%36%23%6%
704
16th to endNight
24%16%30%22%4
631
March1st to 15thNight
28%13%32%19%4
720
16th to endNight
18%20%28%23%8%1
768
April1st to 15thNight
30%13%26%25%4
718
16th to endNight
25%16%29%20%7%
606
May1st to 15thNight
26%8%32%20%9%1
381
16th to endNight
26%11%33%21%7%
375
June1st to 15thNight
25%11%27%26%8%
360
16th to endNight
20%5%30%32%10%1
360
July1st to 15thNight
13%6%30%32%16%1
340
16th to endNight
16%5%25%36%15%
376
August1st to 15thNight
13%321%39%20%1
359
16th to endNight
14%6%24%33%17%2
729
September1st to 15thNight
19%6%27%31%13%1
707
16th to endNight
22%10%25%23%15%2
657
October1st to 15thNight
23%13%28%24%8%1
660
16th to endNight
32%11%27%20%7%
704
November1st to 15thNight
26%12%25%23%10%1
700
16th to endNight
28%17%25%19%7%2
720
December1st to 15thNight
29%15%27%22%4
720
16th to endNight
32%15%25%20%4
768
Page generated at 2017-09-13 07:39:16. Version ac04

Copyright 2017 A. Danko


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