Candiac
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Candiac clear sky chart from 2005-11-05 to 2017-12-01.

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
31%
14945
13%
47781
9%
14915
37%
14915
17%
34198

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
17%
720
8%
2506
4%
716
23%
716
9%
1984
January16th to endNight
20%
768
10%
2688
5%
768
28%
768
11%
2013
February1st to 15thNight
19%
703
8%
2307
4%
701
24%
701
10%
1846
February16th to endNight
25%
631
12%
1893
6%
631
34%
631
13%
1433
March1st to 15thNight
24%
720
14%
2160
10%
720
30%
720
14%
1629
March16th to endNight
32%
768
19%
1999
9%
768
39%
768
23%
1430
April1st to 15thNight
27%
718
16%
1796
5%
718
32%
718
19%
1370
April16th to endNight
29%
618
16%
1698
6%
618
36%
618
21%
1202
May1st to 15thNight
32%
405
17%
1485
14%
405
41%
405
18%
979
May16th to endNight
36%
374
13%
1497
12%
374
45%
374
17%
978
June1st to 15thNight
34%
360
9%
1440
9%
360
42%
360
13%
1005
June16th to endNight
43%
360
9%
1440
11%
360
49%
360
19%
912
July1st to 15thNight
52%
340
13%
1360
19%
340
57%
340
24%
796
July16th to endNight
55%
376
12%
1418
17%
354
59%
354
23%
831
August1st to 15thNight
57%
371
15%
1442
16%
369
59%
369
22%
874
August16th to endNight
55%
756
21%
1902
12%
756
57%
756
35%
1224
September1st to 15thNight
50%
720
15%
1800
8%
720
51%
720
30%
1234
September16th to endNight
49%
717
23%
1977
16%
717
54%
717
31%
1249
October1st to 15thNight
34%
720
18%
2111
10%
720
43%
720
22%
1456
October16th to endNight
25%
768
12%
2466
8%
768
32%
768
15%
1809
November1st to 15thNight
25%
760
17%
2472
11%
760
33%
760
16%
1758
November16th to endNight
23%
780
12%
2704
7%
780
30%
780
11%
2027
December1st to 15thNight
17%
724
7%
2532
3%
724
22%
724
9%
2009
December16th to endNight
14%
768
9%
2688
3%
768
22%
768
8%
2150

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
17%8%36%5%3445%7%32%
48661
Night
19%9%46%5%34446%31%
47950
Cloud CoverDay
18%8%36%5%3445%6%32%
48671
Night
19%9%46%5%34445%31%
47955
TransparencyDay
51%411%20%9%1
48348
Night
54%410%19%10%1
47781
SeeingDay
22%8%26%23%13%4
5841
Night
25%7%27%27%10%
14947

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%15%49%7%35%33321%
1432
16th to endDay
14%14%48%6%45%46%7%23%
1536
February1st to 15thDay
15%12%5%11%8%46%345%23%
1555
16th to endDay
17%12%5%6%7%34445%26%
1580
March1st to 15thDay
17%11%48%7%36%445%26%
1790
16th to endDay
18%9%36%413346%35%
2223
April1st to 15thDay
21%10%36%5%24345%32%
2152
16th to endDay
19%7%35%5%24446%36%
2262
May1st to 15thDay
20%8%25%435%447%32%
2475
16th to endDay
19%6%26%5%25%45%7%34%
2618
June1st to 15thDay
23%6%35%43445%7%30%
2520
16th to endDay
18%6%25%5%35%5%5%8%32%
2520
July1st to 15thDay
12%5%25%5%35%5%6%8%37%
2520
16th to endDay
11%5%25%5%35%7%7%9%36%
2654
August1st to 15thDay
11%5%37%6%35%5%6%9%34%
2496
16th to endDay
10%4234345%6%9%46%
2299
September1st to 15thDay
15%4245%3345%7%43%
2160
16th to endDay
12%42442435%7%48%
1983
October1st to 15thDay
20%6%37%5%3435%6%33%
1848
16th to endDay
24%9%36%6%34445%28%
1758
November1st to 15thDay
18%10%36%4345%5%7%29%
1716
16th to endDay
22%9%5%7%6%3445%426%
1586
December1st to 15thDay
25%12%6%7%6%44446%16%
1442
16th to endDay
27%14%5%7%7%34335%18%
1536
January1st to 15thNight
18%15%6%9%7%35%445%20%
2506
16th to endNight
13%14%6%8%6%5%45%4426%
2688
February1st to 15thNight
15%13%6%11%8%46%34420%
2305
16th to endNight
17%11%5%9%6%35%44427%
1893
March1st to 15thNight
21%12%37%6%34345%28%
2147
16th to endNight
17%9%45%5%34345%37%
1999
April1st to 15thNight
26%9%36%434335%30%
1796
16th to endNight
21%7%35%424345%36%
1698
May1st to 15thNight
20%7%36%5%1335%5%36%
1485
16th to endNight
20%5%35%5%3445%7%34%
1495
June1st to 15thNight
26%7%25%42436%6%29%
1440
16th to endNight
16%5%16%435%6%5%8%35%
1440
July1st to 15thNight
11%4246%35%6%7%8%39%
1440
16th to endNight
11%433435%5%6%10%39%
1514
August1st to 15thNight
13%425%5%35%5%6%8%39%
1452
16th to endNight
12%415%334448%46%
1902
September1st to 15thNight
16%6%25%5%23445%42%
1800
16th to endNight
18%423323336%47%
1977
October1st to 15thNight
17%7%26%5%34446%37%
2111
16th to endNight
25%8%36%424445%29%
2466
November1st to 15thNight
21%9%36%5%35%345%30%
2472
16th to endNight
22%11%48%5%34335%26%
2704
December1st to 15thNight
24%14%6%7%5%33445%20%
2532
16th to endNight
24%17%6%7%42333420%
2688

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%15%5%8%7%35%33421%
1432
16th to endDay
15%14%48%6%45%45%6%24%
1536
February1st to 15thDay
13%14%5%10%8%36%435%22%
1555
16th to endDay
17%12%6%7%6%34446%26%
1580
March1st to 15thDay
18%11%48%8%35%43427%
1800
16th to endDay
19%8%45%5%23446%35%
2223
April1st to 15thDay
22%10%26%43443432%
2152
16th to endDay
21%7%3443445%5%36%
2262
May1st to 15thDay
21%6%35%5%2445%7%33%
2475
16th to endDay
19%6%35%5%345%47%34%
2618
June1st to 15thDay
24%6%2443445%7%30%
2520
16th to endDay
19%6%25%5%36%46%8%33%
2520
July1st to 15thDay
12%435%5%35%5%5%8%38%
2520
16th to endDay
12%5%245%35%6%6%9%36%
2654
August1st to 15thDay
12%5%36%5%36%5%7%8%34%
2496
16th to endDay
10%4144246%6%10%45%
2299
September1st to 15thDay
16%424424346%44%
2160
16th to endDay
12%5%24323447%48%
1983
October1st to 15thDay
20%6%36%5%34446%34%
1848
16th to endDay
24%9%35%6%3435%5%28%
1758
November1st to 15thDay
20%10%35%5%35%446%30%
1716
16th to endDay
22%10%5%7%6%3444426%
1586
December1st to 15thDay
26%11%5%7%7%25%446%17%
1442
16th to endDay
27%15%5%7%6%34335%17%
1536
January1st to 15thNight
19%15%5%9%5%35%5%45%19%
2506
16th to endNight
14%13%6%8%7%45%44426%
2688
February1st to 15thNight
16%13%6%12%7%45%5%3420%
2298
16th to endNight
18%12%5%8%5%45%33427%
1893
March1st to 15thNight
22%11%47%6%34345%28%
2160
16th to endNight
18%9%45%424345%37%
1998
April1st to 15thNight
26%9%45%42433430%
1796
16th to endNight
21%8%245%24346%36%
1698
May1st to 15thNight
19%8%46%423345%36%
1485
16th to endNight
20%5%35%43446%7%34%
1495
June1st to 15thNight
27%6%35%42445%7%28%
1440
16th to endNight
17%425%5%245%7%8%36%
1440
July1st to 15thNight
11%4245%35%6%6%9%40%
1440
16th to endNight
12%4245%35%5%6%9%40%
1514
August1st to 15thNight
13%5%25%435%5%6%8%39%
1452
16th to endNight
12%5%2441445%7%47%
1902
September1st to 15thNight
16%5%25%5%24347%41%
1800
16th to endNight
17%5%23323345%47%
1977
October1st to 15thNight
18%7%36%5%24346%38%
2111
16th to endNight
26%7%36%5%33346%29%
2466
November1st to 15thNight
22%9%25%5%3445%5%30%
2472
16th to endNight
23%11%38%5%24335%27%
2704
December1st to 15thNight
25%14%6%7%5%3434419%
2532
16th to endNight
25%17%6%7%42332420%
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
68%37%13%6%
1433
16th to endDay
59%411%15%7%
1536
February1st to 15thDay
64%38%20%2
1557
16th to endDay
59%411%14%9%1
1580
March1st to 15thDay
60%311%16%7%1
1800
16th to endDay
49%49%19%13%2
2223
April1st to 15thDay
55%37%19%11%2
2152
16th to endDay
48%49%19%14%3
2262
May1st to 15thDay
50%49%19%14%1
2475
16th to endDay
48%5%11%20%11%1
2622
June1st to 15thDay
52%5%11%19%10%1
2520
16th to endDay
49%411%23%9%1
2520
July1st to 15thDay
40%6%13%28%11%
2371
16th to endDay
41%7%16%25%8%
2487
August1st to 15thDay
45%6%16%23%7%
2482
16th to endDay
32%6%18%28%13%
2299
September1st to 15thDay
40%414%28%12%
2160
16th to endDay
35%313%33%12%
1983
October1st to 15thDay
50%411%23%9%
1848
16th to endDay
58%413%17%6%
1758
November1st to 15thDay
54%412%19%9%
1716
16th to endDay
59%5%10%15%8%
1586
December1st to 15thDay
68%5%11%11%2
1442
16th to endDay
69%411%8%5%
1536
January1st to 15thNight
65%410%13%4
2506
16th to endNight
60%49%16%8%
2688
February1st to 15thNight
67%49%14%3
2307
16th to endNight
60%39%15%10%
1893
March1st to 15thNight
59%38%18%8%1
2160
16th to endNight
50%38%18%15%4
1999
April1st to 15thNight
57%25%18%14%1
1796
16th to endNight
50%38%18%15%3
1698
May1st to 15thNight
50%36%19%16%4
1485
16th to endNight
48%5%9%21%12%2
1497
June1st to 15thNight
55%49%20%9%1
1440
16th to endNight
44%6%13%20%14%1
1440
July1st to 15thNight
37%6%12%27%14%
1360
16th to endNight
38%5%17%24%13%
1418
August1st to 15thNight
40%6%18%22%12%
1442
16th to endNight
36%413%30%13%1
1902
September1st to 15thNight
43%311%25%13%1
1800
16th to endNight
38%410%30%15%
1977
October1st to 15thNight
48%410%26%10%
2111
16th to endNight
57%312%18%7%
2466
November1st to 15thNight
54%311%18%8%2
2472
16th to endNight
60%310%17%6%
2704
December1st to 15thNight
67%312%13%2
2532
16th to endNight
68%310%11%5%
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
23%23%20%15%18%
60
16th to endDay
39%431%17%6%1
64
February1st to 15thDay
30%18%34%15%1
96
16th to endDay
28%10%29%24%6%
239
March1st to 15thDay
24%10%35%23%5%
270
16th to endDay
27%8%28%20%12%3
288
April1st to 15thDay
33%9%28%18%8%2
270
16th to endDay
21%11%28%19%16%2
270
May1st to 15thDay
28%7%27%20%11%4
288
16th to endDay
20%12%29%22%13%2
331
June1st to 15thDay
30%6%24%25%10%2
315
16th to endDay
20%9%28%26%14%1
315
July1st to 15thDay
12%6%27%29%16%6%
305
16th to endDay
15%322%32%23%4
326
August1st to 15thDay
15%320%32%20%7%
313
16th to endDay
11%5%23%26%17%15%
332
September1st to 15thDay
17%220%27%17%13%
315
16th to endDay
12%6%27%19%22%11%
314
October1st to 15thDay
20%10%29%20%17%2
315
16th to endDay
33%10%25%22%8%
295
November1st to 15thDay
26%10%26%22%12%1
280
16th to endDay
28%15%31%14%9%
116
December1st to 15thDay
28%10%33%25%11
60
16th to endDay
34%20%31%14%
64
January1st to 15thNight
26%11%32%22%6%
720
16th to endNight
21%12%34%23%7%
768
February1st to 15thNight
22%8%35%25%6%
704
16th to endNight
25%9%32%27%6%
631
March1st to 15thNight
28%9%29%26%5%
720
16th to endNight
24%6%29%27%9%
768
April1st to 15thNight
30%9%27%27%4
718
16th to endNight
26%11%27%22%11%
618
May1st to 15thNight
24%5%28%27%11%1
405
16th to endNight
21%6%28%31%10%
375
June1st to 15thNight
31%321%31%10%
360
16th to endNight
18%326%37%13%1
360
July1st to 15thNight
12%325%34%22%
340
16th to endNight
12%219%49%14%1
376
August1st to 15thNight
15%314%46%19%1
371
16th to endNight
14%220%35%23%2
756
September1st to 15thNight
20%118%39%18%1
720
16th to endNight
21%321%30%19%2
717
October1st to 15thNight
23%7%28%27%13%
720
16th to endNight
31%9%26%25%6%
768
November1st to 15thNight
28%9%28%22%10%
760
16th to endNight
29%12%26%18%11%1
780
December1st to 15thNight
33%10%29%20%4
724
16th to endNight
35%11%29%17%41
768
Page generated at 2017-12-02 09:14:16. Version ac04

Copyright 2017 A. Danko


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