Rencontre East
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rencontre East clear sky chart from 2005-11-05 to 2017-10-31.

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
18%
15148
10%
47326
3%
15101
25%
15101
10%
36791

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%
750
9%
2562
2%
746
19%
746
7%
2059
January16th to endNight
14%
800
12%
2688
3%
800
24%
800
8%
2053
February1st to 15thNight
15%
731
10%
2381
3%
730
23%
730
9%
1812
February16th to endNight
12%
631
10%
1893
1%
631
19%
631
8%
1500
March1st to 15thNight
15%
698
14%
2128
4%
694
24%
694
9%
1665
March16th to endNight
14%
576
10%
2055
3%
576
22%
576
6%
1647
April1st to 15thNight
18%
539
9%
1762
6%
539
25%
539
9%
1366
April16th to endNight
16%
540
11%
1620
5%
540
24%
540
10%
1261
May1st to 15thNight
21%
540
8%
1540
3%
540
24%
540
11%
1219
May16th to endNight
17%
561
7%
1374
1%
560
19%
560
10%
1157
June1st to 15thNight
20%
540
3%
1260
1%
540
21%
540
11%
1056
June16th to endNight
21%
540
4%
1260
2%
540
22%
540
13%
1047
July1st to 15thNight
26%
510
5%
1223
3%
510
27%
510
13%
993
July16th to endNight
21%
565
6%
1419
2%
532
24%
532
11%
1168
August1st to 15thNight
30%
539
8%
1511
4%
535
33%
535
13%
1158
August16th to endNight
27%
573
9%
1737
4%
573
34%
573
13%
1290
September1st to 15thNight
25%
540
8%
1868
6%
540
30%
540
12%
1393
September16th to endNight
26%
538
14%
1980
8%
538
35%
538
14%
1360
October1st to 15thNight
25%
591
15%
2086
7%
591
35%
591
13%
1470
October16th to endNight
19%
816
12%
2494
4%
816
25%
816
11%
1929
November1st to 15thNight
18%
730
11%
2281
4%
730
24%
730
10%
1763
November16th to endNight
12%
750
11%
2624
3%
750
20%
750
7%
2059
December1st to 15thNight
14%
750
10%
2700
3%
750
23%
750
7%
2065
December16th to endNight
13%
800
9%
2880
3%
800
21%
800
6%
2301

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
26%12%47%5%34445%21%
48415
Night
26%12%46%5%24446%24%
47501
TransparencyDay
65%39%14%6%
48098
Night
63%39%15%7%
47336
SeeingDay
30%22%21%16%6%1
8260
Night
28%24%21%19%5%
15150

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%9%7%34345%19%
1373
16th to endDay
22%17%6%10%7%24335%18%
1536
February1st to 15thDay
21%12%49%5%35%447%21%
1477
16th to endDay
18%16%7%10%6%34335%19%
1580
March1st to 15thDay
21%12%5%7%7%3433423%
1811
16th to endDay
20%18%6%9%6%2444318%
2166
April1st to 15thDay
24%14%5%9%6%34445%18%
2186
16th to endDay
25%13%5%9%6%2332422%
2340
May1st to 15thDay
25%12%5%7%5%25%445%21%
2410
16th to endDay
28%11%36%5%3445%6%20%
2737
June1st to 15thDay
30%12%5%7%5%34445%16%
2700
16th to endDay
34%11%36%423335%21%
2700
July1st to 15thDay
27%10%36%423446%26%
2661
16th to endDay
33%9%35%5%24446%20%
2653
August1st to 15thDay
27%9%47%6%3445%6%20%
2436
16th to endDay
27%9%36%5%35%446%22%
2462
September1st to 15thDay
27%10%26%5%3445%5%24%
2091
16th to endDay
22%7%25%5%3445%8%31%
1980
October1st to 15thDay
28%8%25%5%23345%29%
1872
16th to endDay
27%13%36%5%2444422%
1728
November1st to 15thDay
29%13%36%5%23345%22%
1577
16th to endDay
29%15%35%5%33335%21%
1335
December1st to 15thDay
27%14%45%423445%23%
1260
16th to endDay
22%15%5%7%425%336%22%
1344
January1st to 15thNight
22%16%5%7%5%25%45%5%19%
2562
16th to endNight
21%12%5%7%6%23446%24%
2688
February1st to 15thNight
20%12%6%8%5%25%345%25%
2381
16th to endNight
18%16%5%9%5%25%335%24%
1893
March1st to 15thNight
20%14%46%5%34335%26%
2125
16th to endNight
21%15%6%7%6%3445%420%
2055
April1st to 15thNight
26%14%46%423446%23%
1762
16th to endNight
26%10%46%6%33345%26%
1620
May1st to 15thNight
27%9%46%5%2345%6%22%
1540
16th to endNight
34%11%45%424435%19%
1372
June1st to 15thNight
30%11%36%6%34446%19%
1260
16th to endNight
34%10%45%42445%5%19%
1260
July1st to 15thNight
31%11%35%42445%5%21%
1296
16th to endNight
36%9%35%323446%19%
1515
August1st to 15thNight
28%8%25%43345%7%25%
1522
16th to endNight
30%8%34423347%27%
1737
September1st to 15thNight
28%9%35%423445%28%
1868
16th to endNight
24%7%2443445%6%33%
1980
October1st to 15thNight
24%9%24424446%31%
2086
16th to endNight
30%8%3442445%7%23%
2494
November1st to 15thNight
30%12%24424345%25%
2281
16th to endNight
25%15%36%5%3443423%
2624
December1st to 15thNight
28%14%45%423235%25%
2700
16th to endNight
23%14%6%6%6%33345%20%
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
69%36%14%5%
1374
16th to endDay
72%25%10%8%
1536
February1st to 15thDay
65%29%14%7%
1481
16th to endDay
70%37%10%7%
1580
March1st to 15thDay
65%38%14%7%1
1821
16th to endDay
74%35%10%5%
2166
April1st to 15thDay
69%37%11%6%
2186
16th to endDay
68%25%13%9%
2340
May1st to 15thDay
66%49%14%5%
2410
16th to endDay
66%39%14%5%
2741
June1st to 15thDay
71%48%10%4
2700
16th to endDay
67%26%15%6%
2700
July1st to 15thDay
59%311%19%5%
2506
16th to endDay
66%311%14%4
2486
August1st to 15thDay
64%411%13%4
2422
16th to endDay
62%411%17%3
2462
September1st to 15thDay
60%310%18%6%
2091
16th to endDay
51%416%18%8%
1980
October1st to 15thDay
59%49%17%8%1
1872
16th to endDay
66%36%17%5%
1728
November1st to 15thDay
64%311%14%4
1577
16th to endDay
68%39%11%6%1
1335
December1st to 15thDay
66%47%13%7%
1260
16th to endDay
66%36%15%7%
1344
January1st to 15thNight
68%37%13%6%
2562
16th to endNight
62%39%13%10%
2688
February1st to 15thNight
63%29%17%7%
2381
16th to endNight
66%27%15%7%
1893
March1st to 15thNight
63%26%17%8%
2138
16th to endNight
68%37%11%7%
2055
April1st to 15thNight
64%39%13%8%
1762
16th to endNight
64%27%13%10%1
1620
May1st to 15thNight
62%411%15%5%
1540
16th to endNight
68%310%10%6%
1374
June1st to 15thNight
66%5%11%11%4
1260
16th to endNight
66%38%12%8%
1260
July1st to 15thNight
63%49%17%4
1223
16th to endNight
68%310%14%3
1419
August1st to 15thNight
59%5%13%15%5%
1511
16th to endNight
58%314%16%7%
1737
September1st to 15thNight
59%311%16%7%
1868
16th to endNight
52%413%19%8%
1980
October1st to 15thNight
55%312%19%8%
2086
16th to endNight
61%310%17%7%
2494
November1st to 15thNight
63%312%14%6%
2281
16th to endNight
66%38%14%6%
2624
December1st to 15thNight
63%28%16%8%
2700
16th to endNight
68%37%12%7%
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
21%32%26%15%2
240
16th to endDay
25%29%25%14%41
256
February1st to 15thDay
27%29%21%16%4
236
16th to endDay
30%34%19%8%5%
212
March1st to 15thDay
24%31%24%12%5%1
240
16th to endDay
30%29%24%8%5%2
266
April1st to 15thDay
28%28%22%15%4
303
16th to endDay
30%27%19%14%6%1
450
May1st to 15thDay
30%20%16%20%8%2
468
16th to endDay
32%21%24%14%5%1
519
June1st to 15thDay
35%18%18%17%7%1
495
16th to endDay
36%18%22%14%5%2
495
July1st to 15thDay
30%12%24%21%10%1
475
16th to endDay
35%16%18%19%8%1
514
August1st to 15thDay
29%11%23%22%10%2
493
16th to endDay
33%12%19%22%10%1
502
September1st to 15thDay
34%14%25%18%5%1
298
16th to endDay
25%18%30%19%5%1
269
October1st to 15thDay
28%20%24%17%8%1
270
16th to endDay
31%22%20%16%5%2
288
November1st to 15thDay
28%26%22%13%6%2
235
16th to endDay
35%27%21%12%3
240
December1st to 15thDay
27%30%22%13%5%
240
16th to endDay
30%33%17%13%31
256
January1st to 15thNight
26%30%22%17%2
750
16th to endNight
20%33%25%16%3
800
February1st to 15thNight
23%33%22%17%3
733
16th to endNight
25%29%24%15%4
631
March1st to 15thNight
23%32%21%14%8%
698
16th to endNight
22%31%23%16%4
576
April1st to 15thNight
26%27%20%20%4
539
16th to endNight
25%25%27%17%4
540
May1st to 15thNight
29%22%19%20%6%1
540
16th to endNight
31%23%21%19%3
561
June1st to 15thNight
29%21%19%24%5%
540
16th to endNight
32%20%18%21%7%
540
July1st to 15thNight
34%16%17%23%6%
510
16th to endNight
33%19%17%22%6%
565
August1st to 15thNight
30%12%18%24%12%1
539
16th to endNight
31%13%19%23%11%
573
September1st to 15thNight
29%13%22%24%8%
540
16th to endNight
25%15%26%24%7%
538
October1st to 15thNight
28%20%20%22%7%
591
16th to endNight
32%19%21%19%6%
816
November1st to 15thNight
31%23%20%18%5%
730
16th to endNight
33%29%21%14%1
750
December1st to 15thNight
29%30%19%15%4
750
16th to endNight
27%31%20%15%41
800
Page generated at 2017-11-01 18:53:33. Version ac04

Copyright 2017 A. Danko


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