Observatoir "Lac Beauce"
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatoir "Lac Beauce" clear sky chart from 2005-11-05 to 2017-04-26.

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%
14203
10%
45705
6%
14171
31%
14171
12%
34984

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
16%
720
6%
2506
4%
716
20%
716
6%
2114
January16th to endNight
22%
768
9%
2688
5%
768
27%
768
9%
2122
February1st to 15thNight
21%
704
9%
2376
3%
701
27%
701
10%
1883
February16th to endNight
21%
631
9%
1893
6%
631
26%
631
11%
1517
March1st to 15thNight
21%
720
12%
2160
8%
720
27%
720
12%
1669
March16th to endNight
28%
768
17%
2008
6%
768
35%
768
17%
1499
April1st to 15thNight
22%
718
12%
1796
4%
718
26%
718
14%
1435
April16th to endNight
24%
561
15%
1617
6%
561
30%
561
18%
1138
May1st to 15thNight
30%
352
14%
1342
12%
352
39%
352
15%
933
May16th to endNight
25%
343
11%
1369
9%
342
36%
342
13%
972
June1st to 15thNight
28%
330
6%
1205
4%
330
32%
330
11%
886
June16th to endNight
41%
330
5%
1198
5%
330
43%
330
15%
839
July1st to 15thNight
41%
310
6%
1240
8%
310
44%
310
16%
824
July16th to endNight
45%
348
7%
1306
9%
326
46%
326
15%
901
August1st to 15thNight
49%
329
11%
1310
12%
327
52%
327
15%
900
August16th to endNight
41%
629
11%
1679
6%
629
43%
629
22%
1195
September1st to 15thNight
41%
660
11%
1658
5%
660
43%
660
24%
1199
September16th to endNight
36%
657
15%
1815
10%
657
40%
657
24%
1244
October1st to 15thNight
26%
660
13%
1930
7%
660
33%
660
17%
1426
October16th to endNight
20%
704
8%
2288
5%
704
25%
704
9%
1844
November1st to 15thNight
23%
700
13%
2280
8%
700
31%
700
11%
1754
November16th to endNight
21%
726
8%
2554
5%
726
25%
726
7%
2080
December1st to 15thNight
16%
750
4%
2700
2%
750
19%
750
6%
2260
December16th to endNight
14%
785
8%
2787
3%
785
20%
785
5%
2350

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
21%11%47%6%34445%25%
45953
Night
20%11%48%6%34445%25%
45874
TransparencyDay
60%5%10%15%7%
45640
Night
60%5%10%15%6%
45705
SeeingDay
28%13%27%19%9%2
5212
Night
26%11%27%24%8%
14203

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
19%14%7%10%8%45%5%4413%
1432
16th to endDay
14%14%6%10%9%45%5%45%18%
1536
February1st to 15thDay
10%15%6%11%10%6%7%445%17%
1485
16th to endDay
15%17%6%9%8%36%33421%
1580
March1st to 15thDay
17%13%6%9%6%2443427%
1790
16th to endDay
15%12%48%6%35%435%30%
2214
April1st to 15thDay
24%13%46%5%2433427%
2152
16th to endDay
23%11%35%422245%32%
2255
May1st to 15thDay
22%7%36%5%25%347%31%
2287
16th to endDay
24%7%46%6%34346%27%
2394
June1st to 15thDay
25%8%35%5%3445%7%26%
2423
16th to endDay
22%8%46%6%35%5%6%6%25%
2428
July1st to 15thDay
19%6%37%7%45%5%5%7%24%
2310
16th to endDay
18%7%48%6%35%5%5%7%27%
2458
August1st to 15thDay
21%7%48%8%46%5%5%6%21%
2299
16th to endDay
16%6%38%6%35%5%6%8%28%
2168
September1st to 15thDay
23%7%26%423336%34%
1972
16th to endDay
24%6%25%5%24346%33%
1815
October1st to 15thDay
27%11%37%5%24345%24%
1697
16th to endDay
31%15%45%433335%18%
1584
November1st to 15thDay
22%15%48%6%24345%24%
1576
16th to endDay
22%16%6%9%6%2333420%
1404
December1st to 15thDay
25%17%5%9%5%35%23415%
1260
16th to endDay
21%18%7%9%6%3433317%
1434
January1st to 15thNight
20%15%6%11%8%46%33414%
2506
16th to endNight
13%15%6%10%7%46%6%5%6%17%
2688
February1st to 15thNight
9%11%7%11%11%5%6%45%420%
2374
16th to endNight
14%15%5%11%8%45%43322%
1893
March1st to 15thNight
19%13%48%6%35%33426%
2147
16th to endNight
14%9%48%7%36%44431%
2008
April1st to 15thNight
23%13%5%7%6%3323426%
1796
16th to endNight
21%8%36%423336%35%
1617
May1st to 15thNight
19%8%37%5%25%335%32%
1342
16th to endNight
26%7%26%5%2324432%
1367
June1st to 15thNight
23%9%45%5%35%5%45%28%
1205
16th to endNight
20%6%35%7%35%5%6%7%30%
1198
July1st to 15thNight
15%5%37%5%345%6%8%31%
1320
16th to endNight
15%6%37%6%3446%7%34%
1402
August1st to 15thNight
15%6%35%6%45%5%7%8%31%
1320
16th to endNight
16%6%25%6%345%6%8%34%
1679
September1st to 15thNight
22%5%25%423446%37%
1658
16th to endNight
22%6%25%423335%41%
1815
October1st to 15thNight
23%9%35%5%33335%32%
1930
16th to endNight
27%13%47%6%24345%21%
2288
November1st to 15thNight
22%13%47%5%34345%25%
2280
16th to endNight
25%14%5%8%6%3344418%
2554
December1st to 15thNight
23%16%7%10%7%3433316%
2700
16th to endNight
20%18%7%10%8%4433314%
2787

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
72%5%6%10%4
1433
16th to endDay
66%5%7%14%6%
1536
February1st to 15thDay
68%49%10%7%
1487
16th to endDay
66%46%13%7%1
1580
March1st to 15thDay
61%48%14%10%1
1800
16th to endDay
56%46%17%12%2
2214
April1st to 15thDay
61%37%13%10%3
2152
16th to endDay
54%39%14%14%2
2255
May1st to 15thDay
53%49%17%13%1
2287
16th to endDay
58%6%7%15%9%1
2398
June1st to 15thDay
57%5%9%16%9%1
2423
16th to endDay
56%8%11%13%9%
2428
July1st to 15thDay
54%8%13%17%5%
2161
16th to endDay
57%8%12%15%5%
2291
August1st to 15thDay
61%8%13%12%3
2285
16th to endDay
50%9%15%19%4
2168
September1st to 15thDay
51%5%16%17%8%
1972
16th to endDay
51%5%16%20%6%
1815
October1st to 15thDay
63%49%15%6%
1697
16th to endDay
69%49%13%2
1584
November1st to 15thDay
63%5%10%13%5%
1576
16th to endDay
68%411%12%4
1404
December1st to 15thDay
73%48%11%2
1260
16th to endDay
72%36%10%6%
1434
January1st to 15thNight
74%38%10%2
2506
16th to endNight
65%5%9%14%5%
2688
February1st to 15thNight
64%5%9%13%6%
2376
16th to endNight
66%48%13%7%
1893
March1st to 15thNight
61%48%16%9%
2160
16th to endNight
54%48%18%11%2
2008
April1st to 15thNight
63%36%15%10%2
1796
16th to endNight
50%410%17%13%2
1617
May1st to 15thNight
53%49%16%12%2
1342
16th to endNight
56%48%19%10%1
1369
June1st to 15thNight
56%7%10%17%7%
1205
16th to endNight
51%7%11%17%10%1
1198
July1st to 15thNight
47%8%18%18%7%
1240
16th to endNight
48%10%14%19%7%
1306
August1st to 15thNight
47%9%18%21%3
1310
16th to endNight
45%8%18%21%5%
1679
September1st to 15thNight
47%7%14%22%7%
1658
16th to endNight
46%315%27%4
1815
October1st to 15thNight
55%413%17%8%
1930
16th to endNight
65%6%10%13%3
2288
November1st to 15thNight
60%5%12%13%7%
2280
16th to endNight
68%5%9%13%3
2554
December1st to 15thNight
73%410%10%1
2700
16th to endNight
74%37%9%4
2787

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
31%10%40%13%5%
60
16th to endDay
31%10%35%15%41
64
February1st to 15thDay
20%16%46%12%12
78
16th to endDay
27%20%27%16%7%
239
March1st to 15thDay
28%19%26%19%5%
270
16th to endDay
21%21%22%19%12%3
288
April1st to 15thDay
33%14%26%17%7%1
270
16th to endDay
31%17%24%16%7%2
254
May1st to 15thDay
27%10%30%20%9%2
228
16th to endDay
26%13%31%17%8%1
267
June1st to 15thDay
31%11%24%19%12%1
368
16th to endDay
21%9%29%26%11%1
373
July1st to 15thDay
24%9%32%22%6%4
245
16th to endDay
25%428%24%13%2
270
August1st to 15thDay
27%6%22%21%15%6%
253
16th to endDay
20%11%26%23%14%4
268
September1st to 15thDay
29%7%26%20%9%7%
255
16th to endDay
25%12%27%12%14%5%
254
October1st to 15thDay
29%16%22%17%11%3
254
16th to endDay
40%11%22%18%6%1
240
November1st to 15thDay
31%14%25%16%8%3
230
16th to endDay
41%18%25%13%1
60
December1st to 15thDay
33%13%36%11%5%
60
16th to endDay
50%20%23%6%
64
January1st to 15thNight
26%13%32%21%5%
720
16th to endNight
22%13%29%24%8%
768
February1st to 15thNight
15%14%36%25%8%
704
16th to endNight
25%14%30%23%6%
631
March1st to 15thNight
27%14%30%22%5%
720
16th to endNight
21%14%29%22%10%1
768
April1st to 15thNight
31%12%25%23%6%
718
16th to endNight
27%16%29%21%5%
561
May1st to 15thNight
23%10%29%29%7%
352
16th to endNight
32%10%27%24%6%
343
June1st to 15thNight
26%10%28%27%6%
330
16th to endNight
20%7%25%33%12%
330
July1st to 15thNight
17%6%25%36%13%
310
16th to endNight
18%424%39%11%
348
August1st to 15thNight
17%5%19%35%20%
329
16th to endNight
20%7%24%29%15%1
629
September1st to 15thNight
25%422%33%12%1
660
16th to endNight
25%8%25%25%13%1
657
October1st to 15thNight
28%10%28%22%8%
660
16th to endNight
37%12%23%18%7%
704
November1st to 15thNight
30%13%25%20%7%1
700
16th to endNight
34%14%22%20%6%
726
December1st to 15thNight
33%14%26%19%5%
750
16th to endNight
33%15%26%18%6%1
785
Page generated at 2017-04-27 17:48:51. Version ac04

Copyright 2017 A. Danko


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