Ruisseau d'or
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ruisseau d'or clear sky chart from 2005-11-05 to 2017-09-18.

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
22%
14703
10%
46884
6%
14671
28%
14671
10%
35759

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
9%
720
7%
2506
2%
716
15%
716
4%
2074
January16th to endNight
10%
768
6%
2688
2%
768
15%
768
5%
2194
February1st to 15thNight
11%
704
7%
2316
2%
701
17%
701
5%
1906
February16th to endNight
9%
631
10%
1893
2%
631
19%
631
7%
1535
March1st to 15thNight
15%
720
12%
2144
6%
720
23%
720
9%
1683
March16th to endNight
22%
768
15%
2046
6%
768
29%
768
13%
1537
April1st to 15thNight
17%
713
13%
1791
4%
713
23%
713
12%
1391
April16th to endNight
21%
540
14%
1620
4%
540
30%
540
13%
1159
May1st to 15thNight
23%
510
12%
1590
7%
510
30%
510
12%
1167
May16th to endNight
24%
375
10%
1497
8%
374
33%
374
9%
1084
June1st to 15thNight
24%
360
7%
1278
5%
360
30%
360
10%
982
June16th to endNight
33%
360
8%
1279
6%
360
39%
360
14%
884
July1st to 15thNight
38%
340
9%
1360
12%
340
42%
340
14%
901
July16th to endNight
35%
376
10%
1418
10%
354
44%
354
14%
944
August1st to 15thNight
42%
457
9%
1528
6%
455
46%
455
17%
1040
August16th to endNight
41%
637
17%
1783
9%
637
45%
637
25%
1159
September1st to 15thNight
37%
720
11%
1866
5%
720
40%
720
24%
1298
September16th to endNight
40%
669
20%
1847
13%
669
45%
669
26%
1200
October1st to 15thNight
27%
660
14%
1886
7%
660
34%
660
15%
1401
October16th to endNight
17%
704
8%
2288
3%
704
23%
704
8%
1832
November1st to 15thNight
22%
700
13%
2277
10%
700
28%
700
10%
1756
November16th to endNight
19%
733
13%
2475
7%
733
27%
733
8%
1909
December1st to 15thNight
10%
750
4%
2700
2%
750
14%
750
4%
2281
December16th to endNight
8%
788
6%
2808
3%
788
13%
788
3%
2442

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
20%12%48%6%34445%24%
47900
Night
17%12%5%8%6%35%445%26%
47054
TransparencyDay
59%6%9%15%7%
47588
Night
58%6%10%16%7%
46884
SeeingDay
24%25%23%16%7%2
6065
Night
20%29%21%19%7%
14703

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
14%14%8%13%12%4434414%
1432
16th to endDay
10%15%6%13%10%46%5%4416%
1536
February1st to 15thDay
12%17%7%12%12%45%42215%
1540
16th to endDay
10%20%5%13%8%46%43317%
1580
March1st to 15thDay
16%15%7%9%7%3444423%
1805
16th to endDay
17%13%6%10%6%3433328%
2175
April1st to 15thDay
20%15%5%7%5%2333427%
2155
16th to endDay
22%12%35%423335%31%
2340
May1st to 15thDay
24%11%46%5%34345%26%
2370
16th to endDay
22%10%47%5%45%35%7%23%
2618
June1st to 15thDay
31%8%25%6%3445%6%20%
2679
16th to endDay
22%8%37%5%36%5%5%7%23%
2676
July1st to 15thDay
18%8%36%6%45%5%6%8%27%
2520
16th to endDay
20%8%38%6%46%6%5%7%22%
2654
August1st to 15thDay
22%7%48%6%45%5%6%7%22%
2409
16th to endDay
18%6%37%5%2435%6%36%
2417
September1st to 15thDay
22%7%25%433446%35%
2094
16th to endDay
20%6%34423447%38%
1838
October1st to 15thDay
19%14%47%5%23346%28%
1741
16th to endDay
23%21%48%5%23435%18%
1584
November1st to 15thDay
18%19%5%6%42443425%
1581
16th to endDay
18%14%7%10%5%2434422%
1483
December1st to 15thDay
20%20%8%10%7%3442314%
1260
16th to endDay
19%21%9%12%6%3432312%
1413
January1st to 15thNight
13%16%8%12%10%46%44315%
2506
16th to endNight
9%15%8%13%10%5%7%6%4315%
2688
February1st to 15thNight
9%14%7%14%11%5%7%34417%
2315
16th to endNight
12%17%7%12%7%45%32421%
1893
March1st to 15thNight
16%13%6%9%5%35%33427%
2131
16th to endNight
14%13%6%8%5%3444431%
2046
April1st to 15thNight
19%13%5%6%6%24345%27%
1791
16th to endNight
20%11%345%235%45%33%
1620
May1st to 15thNight
21%9%46%5%34447%28%
1590
16th to endNight
22%9%36%5%3446%7%27%
1495
June1st to 15thNight
28%9%27%5%25%345%25%
1278
16th to endNight
19%6%36%5%25%45%8%33%
1279
July1st to 15thNight
16%7%25%445%5%6%7%34%
1440
16th to endNight
15%5%26%5%35%6%7%7%34%
1514
August1st to 15thNight
15%6%36%6%35%5%5%8%34%
1538
16th to endNight
14%5%25%425%45%7%42%
1783
September1st to 15thNight
18%8%26%32445%6%37%
1866
16th to endNight
18%5%14332336%45%
1847
October1st to 15thNight
19%10%36%5%24336%32%
1886
16th to endNight
25%16%37%5%3343322%
2288
November1st to 15thNight
20%15%5%6%5%34345%25%
2277
16th to endNight
17%15%6%9%7%2333425%
2475
December1st to 15thNight
19%19%8%12%6%3433313%
2700
16th to endNight
19%18%9%11%10%3433312%
2808

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%6%8%10%5%
1433
16th to endDay
63%8%7%13%6%
1536
February1st to 15thDay
72%6%5%9%5%
1543
16th to endDay
69%5%5%9%7%1
1580
March1st to 15thDay
63%48%13%7%1
1815
16th to endDay
60%46%14%10%1
2175
April1st to 15thDay
60%37%15%9%2
2155
16th to endDay
55%49%16%11%3
2340
May1st to 15thDay
59%48%16%9%
2370
16th to endDay
60%7%10%14%7%
2622
June1st to 15thDay
64%5%9%15%4
2679
16th to endDay
58%8%9%19%5%
2676
July1st to 15thDay
51%9%14%19%6%
2371
16th to endDay
59%8%11%16%4
2487
August1st to 15thDay
57%7%14%16%3
2395
16th to endDay
47%6%14%21%9%
2417
September1st to 15thDay
48%6%12%21%10%
2094
16th to endDay
44%5%11%25%11%
1838
October1st to 15thDay
55%5%10%19%8%
1741
16th to endDay
67%5%8%13%5%
1584
November1st to 15thDay
61%5%10%13%8%
1581
16th to endDay
61%6%9%15%6%1
1483
December1st to 15thDay
72%6%6%10%2
1260
16th to endDay
75%45%7%6%
1413
January1st to 15thNight
67%8%8%10%4
2506
16th to endNight
65%9%9%11%4
2688
February1st to 15thNight
67%6%7%12%4
2316
16th to endNight
66%5%6%12%8%
1893
March1st to 15thNight
61%5%6%16%7%1
2144
16th to endNight
53%6%9%16%11%2
2046
April1st to 15thNight
58%5%6%16%12%1
1791
16th to endNight
51%6%10%17%11%3
1620
May1st to 15thNight
54%6%9%18%9%1
1590
16th to endNight
56%6%12%17%6%
1497
June1st to 15thNight
61%5%10%16%5%
1278
16th to endNight
49%7%13%21%7%
1279
July1st to 15thNight
45%9%15%20%8%
1360
16th to endNight
45%9%15%21%7%
1418
August1st to 15thNight
44%10%19%22%3
1528
16th to endNight
37%8%17%26%8%
1783
September1st to 15thNight
43%6%15%26%7%
1866
16th to endNight
40%5%13%28%11%
1847
October1st to 15thNight
53%6%10%19%9%
1886
16th to endNight
64%6%8%14%5%
2288
November1st to 15thNight
61%5%10%13%7%1
2277
16th to endNight
62%5%9%15%6%
2475
December1st to 15thNight
73%5%7%10%2
2700
16th to endNight
74%7%5%6%5%
2808

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%31%40%10%
60
16th to endDay
25%23%34%12%4
64
February1st to 15thDay
29%29%22%15%3
164
16th to endDay
21%36%20%17%3
239
March1st to 15thDay
28%30%24%11%4
270
16th to endDay
24%30%19%15%7%2
288
April1st to 15thDay
27%28%25%11%42
270
16th to endDay
29%31%19%11%43
270
May1st to 15thDay
36%24%22%8%5%2
288
16th to endDay
22%27%29%15%3
331
June1st to 15thDay
29%24%22%15%7%
474
16th to endDay
21%23%25%19%8%1
471
July1st to 15thDay
19%20%31%17%10%
305
16th to endDay
15%21%28%24%8%
326
August1st to 15thDay
19%20%26%18%11%2
313
16th to endDay
18%20%20%19%14%6%
332
September1st to 15thDay
18%17%26%19%12%6%
315
16th to endDay
19%18%20%19%13%9%
262
October1st to 15thDay
22%28%14%16%12%5%
246
16th to endDay
29%30%15%16%6%
240
November1st to 15thDay
23%28%20%19%7%1
235
16th to endDay
25%28%21%14%6%3
178
December1st to 15thDay
33%30%31%5%
60
16th to endDay
43%31%20%4
64
January1st to 15thNight
17%41%25%11%3
720
16th to endNight
14%38%27%16%2
768
February1st to 15thNight
17%37%25%17%2
704
16th to endNight
20%35%28%11%2
631
March1st to 15thNight
24%32%22%17%2
720
16th to endNight
19%34%19%19%6%
768
April1st to 15thNight
21%34%22%17%5%
713
16th to endNight
24%29%21%17%6%
540
May1st to 15thNight
20%28%21%19%7%1
510
16th to endNight
20%26%21%22%8%
375
June1st to 15thNight
24%26%16%25%6%
360
16th to endNight
19%21%18%26%12%
360
July1st to 15thNight
15%16%23%28%13%2
340
16th to endNight
15%21%19%27%14%
376
August1st to 15thNight
14%14%20%28%21%1
457
16th to endNight
13%15%22%27%18%2
637
September1st to 15thNight
17%17%21%26%15%1
720
16th to endNight
18%17%19%25%16%2
669
October1st to 15thNight
24%21%20%21%10%1
660
16th to endNight
28%27%21%16%5%
704
November1st to 15thNight
19%31%19%19%8%1
700
16th to endNight
22%34%18%14%8%2
733
December1st to 15thNight
27%36%20%12%3
750
16th to endNight
26%36%18%12%4
788
Page generated at 2017-09-19 07:32:25. Version ac04

Copyright 2017 A. Danko


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