Brantford
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Brantford clear sky chart from 2005-11-05 to 2018-02-14.

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
35%
15495
15%
48686
10%
15459
41%
15459
19%
33737

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%
776
10%
2622
5%
776
23%
776
9%
2052
January16th to endNight
16%
832
11%
2704
4%
832
24%
832
10%
2109
February1st to 15thNight
17%
757
8%
2468
2%
757
24%
757
10%
1930
February16th to endNight
23%
631
11%
1990
4%
631
31%
631
13%
1471
March1st to 15thNight
25%
720
13%
1986
7%
720
31%
720
16%
1522
March16th to endNight
32%
768
20%
2112
11%
768
40%
768
23%
1457
April1st to 15thNight
29%
718
15%
1844
6%
718
34%
718
22%
1341
April16th to endNight
39%
540
21%
1620
10%
540
47%
540
26%
1041
May1st to 15thNight
43%
540
16%
1620
10%
540
48%
540
24%
1075
May16th to endNight
48%
376
17%
1499
16%
376
57%
376
24%
861
June1st to 15thNight
46%
360
13%
1440
12%
360
55%
360
21%
854
June16th to endNight
54%
360
15%
1314
17%
360
61%
360
25%
779
July1st to 15thNight
64%
340
18%
1308
21%
340
69%
340
35%
655
July16th to endNight
62%
553
15%
1584
14%
520
64%
520
33%
932
August1st to 15thNight
67%
539
18%
1609
14%
536
70%
536
35%
949
August16th to endNight
63%
608
23%
1754
16%
608
67%
608
36%
1032
September1st to 15thNight
55%
720
22%
1848
13%
720
59%
720
34%
1187
September16th to endNight
59%
717
23%
1982
17%
717
62%
717
33%
1227
October1st to 15thNight
42%
720
18%
2160
16%
720
48%
720
24%
1421
October16th to endNight
26%
768
17%
2304
10%
768
35%
768
17%
1676
November1st to 15thNight
35%
760
17%
2546
15%
760
41%
760
20%
1687
November16th to endNight
25%
780
12%
2730
6%
780
32%
780
12%
1979
December1st to 15thNight
15%
780
6%
2730
3%
780
19%
780
8%
2131
December16th to endNight
13%
832
8%
2912
2%
832
20%
832
6%
2369

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
15%8%36%6%35%5%5%7%32%
49368
Night
15%8%36%5%3445%7%35%
48868
Cloud CoverDay
14%8%36%6%35%5%5%7%32%
49378
Night
15%8%36%5%3445%7%35%
48872
TransparencyDay
50%7%13%18%9%
49068
Night
48%6%12%20%11%1
48686
SeeingDay
17%8%26%23%15%7%
5928
Night
18%9%28%28%12%1
15503

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%12%5%8%6%45%5%47%20%
1643
16th to endDay
14%15%7%11%8%345%45%18%
1872
February1st to 15thDay
16%14%7%11%6%35%346%19%
1695
16th to endDay
17%12%5%9%8%35%5%35%22%
1482
March1st to 15thDay
16%11%6%8%6%45%446%25%
1962
16th to endDay
15%10%5%7%5%35%45%5%32%
2112
April1st to 15thDay
20%9%46%6%3445%6%29%
2115
16th to endDay
18%8%26%324446%38%
2340
May1st to 15thDay
16%7%36%6%345%47%35%
2331
16th to endDay
13%5%25%6%35%5%47%41%
2613
June1st to 15thDay
13%6%25%5%25%5%6%7%38%
2520
16th to endDay
12%4146%36%5%6%9%37%
2639
July1st to 15thDay
9%424445%5%7%9%40%
2565
16th to endDay
10%425%5%46%6%7%9%36%
2474
August1st to 15thDay
9%425%5%36%7%7%9%37%
2340
16th to endDay
11%5%25%5%445%6%8%39%
2435
September1st to 15thDay
13%6%35%6%35%5%5%8%36%
2111
16th to endDay
13%5%26%4345%48%40%
1977
October1st to 15thDay
19%6%36%5%44446%33%
1800
16th to endDay
23%9%36%6%3445%5%25%
1920
November1st to 15thDay
14%8%35%6%25%46%8%33%
1638
16th to endDay
18%13%37%6%245%6%7%23%
1560
December1st to 15thDay
16%16%5%9%8%35%436%21%
1560
16th to endDay
20%15%7%9%7%35%46%414%
1664
January1st to 15thNight
20%12%5%9%6%34446%22%
2622
16th to endNight
14%13%7%10%7%345%5%5%22%
2704
February1st to 15thNight
15%13%5%8%8%35%5%5%5%23%
2466
16th to endNight
16%10%5%8%6%35%35%7%27%
1990
March1st to 15thNight
19%9%36%7%345%5%5%29%
1974
16th to endNight
15%9%45%423345%40%
2112
April1st to 15thNight
19%7%35%434347%35%
1844
16th to endNight
11%5%26%5%34448%42%
1620
May1st to 15thNight
16%5%36%43446%7%38%
1620
16th to endNight
12%42443435%8%46%
1497
June1st to 15thNight
11%5%24435%5%7%8%42%
1440
16th to endNight
10%315%6%35%5%5%7%45%
1314
July1st to 15thNight
5%214423449%56%
1388
16th to endNight
7%4245%2446%8%49%
1691
August1st to 15thNight
6%314325%5%8%9%48%
1620
16th to endNight
8%315%425%35%7%53%
1754
September1st to 15thNight
11%42442445%7%48%
1848
16th to endNight
10%4245%3445%7%47%
1982
October1st to 15thNight
18%6%245%2335%6%41%
2160
16th to endNight
20%8%36%425%45%6%31%
2304
November1st to 15thNight
16%7%25%4345%6%7%36%
2546
16th to endNight
20%10%36%425%5%5%7%28%
2730
December1st to 15thNight
20%13%5%7%6%25%446%22%
2730
16th to endNight
21%13%6%9%6%35%45%5%17%
2912

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
18%12%5%8%6%5%445%7%20%
1643
16th to endDay
13%16%7%12%9%35%45%418%
1872
February1st to 15thDay
16%14%8%10%7%34445%19%
1695
16th to endDay
17%12%5%10%7%36%436%22%
1482
March1st to 15thDay
15%11%6%8%7%35%45%6%24%
1973
16th to endDay
15%9%5%6%6%35%35%5%33%
2111
April1st to 15thDay
20%9%37%6%34346%29%
2115
16th to endDay
17%8%36%423445%38%
2340
May1st to 15thDay
15%7%36%6%345%46%35%
2331
16th to endDay
12%5%25%5%35%45%8%40%
2613
June1st to 15thDay
12%6%25%5%25%5%6%8%37%
2520
16th to endDay
12%4145%45%6%7%9%37%
2639
July1st to 15thDay
8%5%245%45%6%6%9%40%
2565
16th to endDay
9%435%5%36%6%7%9%36%
2474
August1st to 15thDay
9%426%5%37%6%8%9%37%
2340
16th to endDay
11%5%346%445%6%8%39%
2435
September1st to 15thDay
13%6%25%6%35%45%8%36%
2111
16th to endDay
14%5%25%5%35%5%5%8%40%
1977
October1st to 15thDay
18%7%27%5%3445%6%33%
1800
16th to endDay
22%10%36%6%35%5%5%6%25%
1920
November1st to 15thDay
14%8%36%6%25%46%8%33%
1638
16th to endDay
19%12%37%6%346%6%7%23%
1560
December1st to 15thDay
16%15%6%9%7%35%335%21%
1560
16th to endDay
20%15%6%11%7%45%46%5%14%
1664
January1st to 15thNight
20%12%5%9%6%25%445%22%
2622
16th to endNight
14%13%6%10%6%345%5%6%22%
2704
February1st to 15thNight
15%13%5%8%8%35%45%5%22%
2459
16th to endNight
16%10%5%8%6%35%447%27%
1990
March1st to 15thNight
20%8%36%6%345%5%6%28%
1986
16th to endNight
14%9%45%423346%39%
2112
April1st to 15thNight
19%7%36%434447%35%
1844
16th to endNight
11%5%35%5%34447%42%
1620
May1st to 15thNight
15%5%26%5%35%45%7%37%
1619
16th to endNight
12%415%42446%7%46%
1497
June1st to 15thNight
10%5%245%35%5%7%8%42%
1440
16th to endNight
9%325%6%25%5%5%7%44%
1314
July1st to 15thNight
5%21433445%9%55%
1388
16th to endNight
7%4245%245%5%8%49%
1691
August1st to 15thNight
6%214425%5%8%9%47%
1620
16th to endNight
7%315%424347%52%
1754
September1st to 15thNight
11%5%245%2445%7%47%
1848
16th to endNight
11%315%43445%7%47%
1982
October1st to 15thNight
17%6%25%42335%6%41%
2160
16th to endNight
20%7%46%435%45%6%31%
2304
November1st to 15thNight
15%7%25%43446%7%36%
2546
16th to endNight
20%10%35%435%45%7%28%
2730
December1st to 15thNight
20%14%5%7%6%34446%22%
2730
16th to endNight
20%13%7%9%6%45%45%5%17%
2912

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
63%6%10%12%7%
1644
16th to endDay
67%6%10%9%4
1872
February1st to 15thDay
66%6%10%12%3
1697
16th to endDay
63%5%11%13%4
1482
March1st to 15thDay
59%6%12%15%5%
1973
16th to endDay
52%5%11%18%9%1
2112
April1st to 15thDay
55%5%11%16%10%
2115
16th to endDay
47%5%10%20%13%2
2340
May1st to 15thDay
48%6%12%20%11%
2331
16th to endDay
42%6%13%22%13%1
2617
June1st to 15thDay
41%7%14%22%12%1
2520
16th to endDay
40%8%14%22%13%
2639
July1st to 15thDay
35%8%12%24%16%1
2416
16th to endDay
40%9%16%21%11%1
2318
August1st to 15thDay
39%9%15%20%12%1
2327
16th to endDay
39%8%14%24%11%1
2435
September1st to 15thDay
43%7%13%22%12%
2111
16th to endDay
40%7%14%26%10%
1977
October1st to 15thDay
50%6%12%17%10%1
1800
16th to endDay
58%7%13%14%5%
1920
November1st to 15thDay
47%8%15%20%8%
1638
16th to endDay
57%7%15%13%5%
1560
December1st to 15thDay
64%7%14%10%3
1560
16th to endDay
70%7%9%9%2
1664
January1st to 15thNight
63%5%10%11%8%
2622
16th to endNight
61%6%11%14%5%
2704
February1st to 15thNight
62%6%11%14%5%
2468
16th to endNight
56%5%12%16%7%
1990
March1st to 15thNight
55%7%11%18%6%
1986
16th to endNight
46%5%8%22%15%2
2112
April1st to 15thNight
50%5%10%20%13%
1844
16th to endNight
40%6%10%20%18%3
1620
May1st to 15thNight
44%5%11%24%12%2
1620
16th to endNight
35%7%14%24%14%3
1499
June1st to 15thNight
37%8%12%24%15%1
1440
16th to endNight
36%6%13%23%17%1
1314
July1st to 15thNight
26%6%12%27%24%3
1308
16th to endNight
31%7%14%25%17%3
1584
August1st to 15thNight
27%10%16%30%12%2
1609
16th to endNight
30%6%12%31%16%2
1754
September1st to 15thNight
35%6%12%27%16%1
1848
16th to endNight
34%5%13%29%15%1
1982
October1st to 15thNight
42%6%10%24%15%
2160
16th to endNight
51%7%11%19%8%
2304
November1st to 15thNight
44%7%14%19%12%1
2546
16th to endNight
54%6%15%16%6%
2730
December1st to 15thNight
62%7%13%11%4
2730
16th to endNight
68%5%10%10%3
2912

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%19%39%10%9%
111
16th to endDay
31%15%36%12%2
144
February1st to 15thDay
26%20%42%11%
130
16th to endDay
22%22%34%20%
81
March1st to 15thDay
24%9%32%25%7%
263
16th to endDay
25%5%33%24%9%2
288
April1st to 15thDay
23%11%31%21%9%1
270
16th to endDay
20%9%26%22%13%7%
270
May1st to 15thDay
19%7%25%25%13%7%
288
16th to endDay
14%8%26%26%15%8%
331
June1st to 15thDay
15%7%26%30%15%3
315
16th to endDay
13%7%27%30%14%5%
434
July1st to 15thDay
10%5%22%27%23%11%
350
16th to endDay
9%221%30%24%11%
326
August1st to 15thDay
10%117%26%26%16%
313
16th to endDay
12%317%20%23%21%
332
September1st to 15thDay
12%415%23%28%15%
315
16th to endDay
14%5%15%20%26%18%
314
October1st to 15thDay
21%6%25%23%16%7%
315
16th to endDay
25%9%31%23%8%1
336
November1st to 15thDay
21%12%29%22%11%3
126
16th to endDay
25%16%35%14%5%2
90
December1st to 15thDay
22%23%34%14%5%
90
16th to endDay
25%23%38%9%3
96
January1st to 15thNight
24%17%33%18%5%
780
16th to endNight
21%14%36%22%4
832
February1st to 15thNight
23%15%35%21%3
760
16th to endNight
22%12%33%26%5%
631
March1st to 15thNight
23%12%32%25%6%
720
16th to endNight
17%10%32%27%11%
768
April1st to 15thNight
22%11%30%27%6%
718
16th to endNight
12%7%33%33%12%1
540
May1st to 15thNight
16%330%32%15%1
540
16th to endNight
14%329%34%17%1
377
June1st to 15thNight
12%329%39%15%
360
16th to endNight
10%326%44%15%
360
July1st to 15thNight
5%25%46%21%1
340
16th to endNight
9%218%44%22%2
553
August1st to 15thNight
6%15%44%28%3
539
16th to endNight
9%216%35%34%2
608
September1st to 15thNight
13%419%32%25%5%
720
16th to endNight
12%318%29%28%7%
717
October1st to 15thNight
19%7%24%27%17%3
720
16th to endNight
25%10%31%26%5%
768
November1st to 15thNight
18%8%31%26%13%1
760
16th to endNight
25%13%29%22%8%
780
December1st to 15thNight
28%15%32%18%4
780
16th to endNight
26%14%35%19%3
832
Page generated at 2018-02-15 10:58:49. Version ac04

Copyright 2018 A. Danko


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