Brampton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Brampton clear sky chart from 2005-11-05 to 2017-08-12.

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
34%
14699
15%
46372
9%
14662
41%
14662
20%
31596

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
15%
718
10%
2461
3%
716
23%
716
9%
1904
January16th to endNight
17%
768
13%
2496
5%
768
27%
768
12%
1889
February1st to 15thNight
16%
701
10%
2287
2%
701
26%
701
12%
1729
February16th to endNight
22%
631
13%
2012
4%
631
32%
631
15%
1446
March1st to 15thNight
23%
720
14%
1980
6%
720
30%
720
17%
1454
March16th to endNight
31%
768
21%
2112
11%
768
39%
768
24%
1440
April1st to 15thNight
27%
718
15%
1826
5%
718
33%
718
23%
1306
April16th to endNight
36%
552
20%
1632
8%
552
46%
552
27%
1047
May1st to 15thNight
46%
504
17%
1584
11%
504
53%
504
26%
1016
May16th to endNight
48%
374
17%
1497
15%
374
57%
374
26%
833
June1st to 15thNight
46%
360
13%
1440
11%
360
57%
360
22%
843
June16th to endNight
55%
360
15%
1314
16%
360
61%
360
27%
760
July1st to 15thNight
64%
340
18%
1312
23%
340
70%
340
36%
657
July16th to endNight
62%
503
17%
1535
16%
471
64%
471
33%
862
August1st to 15thNight
66%
527
18%
1575
13%
524
69%
524
37%
910
August16th to endNight
60%
566
22%
1616
15%
566
63%
566
34%
968
September1st to 15thNight
53%
660
22%
1669
10%
660
59%
660
35%
1057
September16th to endNight
54%
657
21%
1830
15%
657
58%
657
33%
1127
October1st to 15thNight
40%
660
19%
1980
15%
660
47%
660
24%
1311
October16th to endNight
25%
704
13%
2112
6%
704
33%
704
16%
1557
November1st to 15thNight
35%
700
19%
2374
15%
700
42%
700
20%
1562
November16th to endNight
27%
720
11%
2520
7%
720
34%
720
14%
1813
December1st to 15thNight
16%
720
8%
2520
3%
720
22%
720
10%
1929
December16th to endNight
13%
768
7%
2688
2%
768
18%
768
8%
2176

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
14%8%36%6%35%5%5%7%33%
47585
Night
14%7%36%5%3445%6%36%
46553
Cloud CoverDay
14%8%36%6%35%5%5%7%33%
47595
Night
14%7%36%5%3445%6%36%
46557
TransparencyDay
48%5%14%20%10%
47285
Night
47%5%12%21%11%1
46372
SeeingDay
16%8%26%26%14%6%
5349
Night
18%8%30%28%12%1
14705

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
15%14%5%8%7%445%5%6%22%
1476
16th to endDay
11%15%6%9%9%47%5%46%18%
1728
February1st to 15thDay
13%13%5%11%9%345%5%5%21%
1575
16th to endDay
17%12%5%7%6%3445%6%27%
1460
March1st to 15thDay
14%8%5%8%7%35%45%5%29%
1969
16th to endDay
14%8%48%5%25%44435%
2112
April1st to 15thDay
18%8%46%5%34447%32%
2122
16th to endDay
17%8%25%5%23345%40%
2337
May1st to 15thDay
16%6%26%6%345%5%7%35%
2366
16th to endDay
11%5%25%5%35%5%5%8%40%
2618
June1st to 15thDay
14%5%25%5%35%46%9%38%
2520
16th to endDay
11%425%5%35%5%6%9%38%
2637
July1st to 15thDay
7%325%6%46%6%7%8%40%
2562
16th to endDay
9%5%35%6%46%6%6%9%37%
2525
August1st to 15thDay
7%5%26%5%47%6%6%9%38%
2288
16th to endDay
10%5%25%5%345%7%8%40%
2223
September1st to 15thDay
14%5%25%6%34448%39%
1958
16th to endDay
14%436%5%2446%8%39%
1799
October1st to 15thDay
18%7%26%6%345%46%34%
1650
16th to endDay
25%10%46%5%3445%6%23%
1760
November1st to 15thDay
12%8%37%5%345%6%8%33%
1484
16th to endDay
16%13%6%6%5%45%5%6%6%24%
1440
December1st to 15thDay
16%14%6%10%7%45%5%5%6%18%
1440
16th to endDay
19%13%5%9%6%36%5%5%6%17%
1536
January1st to 15thNight
20%12%48%6%345%5%5%23%
2461
16th to endNight
13%10%6%9%9%45%5%46%24%
2496
February1st to 15thNight
13%10%48%8%45%5%5%5%26%
2285
16th to endNight
12%10%48%7%46%5%46%28%
2012
March1st to 15thNight
18%7%46%5%35%45%6%31%
1968
16th to endNight
14%8%36%5%2434442%
2112
April1st to 15thNight
17%7%35%435%45%6%36%
1826
16th to endNight
12%6%35%5%34446%43%
1632
May1st to 15thNight
15%325%435%5%5%7%41%
1584
16th to endNight
12%324334447%48%
1495
June1st to 15thNight
12%4245%35%46%8%42%
1440
16th to endNight
9%425%425%36%8%47%
1314
July1st to 15thNight
5%31332435%7%58%
1392
16th to endNight
7%3144345%6%8%50%
1641
August1st to 15thNight
6%31442345%8%52%
1586
16th to endNight
8%5%14334445%52%
1616
September1st to 15thNight
11%42442446%7%48%
1669
16th to endNight
13%414423447%49%
1830
October1st to 15thNight
17%5%36%434346%40%
1980
16th to endNight
20%8%26%6%345%5%5%29%
2112
November1st to 15thNight
15%7%25%5%345%5%7%36%
2374
16th to endNight
19%9%47%5%25%45%8%28%
2520
December1st to 15thNight
19%12%47%6%245%6%7%22%
2520
16th to endNight
20%13%7%9%7%45%45%6%18%
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
16%14%5%8%8%35%45%6%22%
1476
16th to endDay
12%14%7%10%9%47%45%5%18%
1728
February1st to 15thDay
14%12%6%10%8%45%446%20%
1575
16th to endDay
17%11%48%6%2445%7%26%
1460
March1st to 15thDay
15%9%49%7%35%5%5%6%29%
1980
16th to endDay
14%8%47%5%3445%436%
2111
April1st to 15thDay
18%8%37%5%3435%6%32%
2122
16th to endDay
17%7%26%5%23345%39%
2337
May1st to 15thDay
15%6%36%6%35%45%7%35%
2366
16th to endDay
11%5%25%5%35%5%5%8%40%
2618
June1st to 15thDay
14%5%15%5%25%46%8%38%
2520
16th to endDay
12%5%245%35%5%6%9%37%
2637
July1st to 15thDay
7%425%6%36%6%7%9%40%
2562
16th to endDay
9%5%35%6%45%6%6%9%37%
2525
August1st to 15thDay
7%5%26%5%37%6%7%8%38%
2288
16th to endDay
10%5%25%5%35%5%6%9%40%
2223
September1st to 15thDay
15%5%25%6%3445%7%39%
1958
16th to endDay
14%436%43445%9%38%
1799
October1st to 15thDay
18%6%25%6%345%46%34%
1650
16th to endDay
25%10%36%5%25%46%6%23%
1760
November1st to 15thDay
13%9%46%5%35%35%9%34%
1484
16th to endDay
17%13%46%6%45%45%7%24%
1440
December1st to 15thDay
17%14%6%9%7%35%5%46%19%
1440
16th to endDay
20%13%5%9%6%346%5%6%17%
1536
January1st to 15thNight
20%13%5%8%6%345%45%22%
2461
16th to endNight
13%11%5%9%8%35%5%5%6%24%
2496
February1st to 15thNight
13%11%5%8%8%36%5%5%5%26%
2278
16th to endNight
12%11%49%7%45%5%46%28%
2012
March1st to 15thNight
18%7%47%5%45%45%6%30%
1980
16th to endNight
14%8%45%42433443%
2112
April1st to 15thNight
17%7%35%435%45%6%35%
1826
16th to endNight
12%6%25%5%245%46%44%
1632
May1st to 15thNight
15%424435%5%5%7%40%
1583
16th to endNight
12%4243245%5%7%48%
1495
June1st to 15thNight
12%4245%25%5%6%8%42%
1440
16th to endNight
9%4245%25%45%8%46%
1314
July1st to 15thNight
6%313324448%57%
1392
16th to endNight
7%31443346%8%50%
1641
August1st to 15thNight
6%4145%3346%8%52%
1586
16th to endNight
9%415%424445%52%
1616
September1st to 15thNight
11%4244245%6%6%48%
1669
16th to endNight
12%424423447%48%
1830
October1st to 15thNight
16%6%25%5%24346%40%
1980
16th to endNight
20%8%37%5%345%5%5%30%
2112
November1st to 15thNight
16%7%25%5%245%5%7%37%
2374
16th to endNight
19%9%47%5%3446%7%27%
2520
December1st to 15thNight
20%12%47%6%245%5%6%23%
2520
16th to endNight
20%13%6%9%6%35%445%18%
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
62%5%12%13%5%
1477
16th to endDay
66%5%9%12%5%
1728
February1st to 15thDay
64%412%14%3
1577
16th to endDay
56%5%13%15%7%1
1460
March1st to 15thDay
56%413%17%8%
1980
16th to endDay
50%310%20%13%1
2112
April1st to 15thDay
52%411%19%11%
2122
16th to endDay
47%310%21%14%2
2337
May1st to 15thDay
46%5%12%22%12%
2366
16th to endDay
40%6%15%22%14%1
2622
June1st to 15thDay
41%5%13%25%12%
2520
16th to endDay
39%7%16%23%13%
2637
July1st to 15thDay
35%6%14%24%16%2
2413
16th to endDay
40%7%15%22%11%2
2369
August1st to 15thDay
38%7%17%20%14%1
2275
16th to endDay
37%6%16%28%10%
2223
September1st to 15thDay
42%6%15%24%10%
1958
16th to endDay
41%6%14%27%9%
1799
October1st to 15thDay
48%5%13%20%9%1
1650
16th to endDay
59%6%15%13%4
1760
November1st to 15thDay
47%6%17%19%8%
1484
16th to endDay
58%6%15%15%4
1440
December1st to 15thDay
65%6%14%11%1
1440
16th to endDay
65%7%12%11%2
1536
January1st to 15thNight
63%411%13%6%
2461
16th to endNight
59%5%12%16%5%
2496
February1st to 15thNight
58%6%11%17%6%
2287
16th to endNight
55%314%18%7%
2012
March1st to 15thNight
53%5%12%20%7%
1980
16th to endNight
45%49%22%16%2
2112
April1st to 15thNight
48%5%10%19%14%
1826
16th to endNight
40%411%21%17%3
1632
May1st to 15thNight
40%6%11%23%15%1
1584
16th to endNight
35%5%13%26%15%3
1497
June1st to 15thNight
38%6%12%23%17%1
1440
16th to endNight
35%6%12%26%17%1
1314
July1st to 15thNight
25%5%12%27%25%2
1312
16th to endNight
31%5%15%26%17%3
1535
August1st to 15thNight
29%6%17%30%13%2
1575
16th to endNight
33%5%9%31%17%2
1616
September1st to 15thNight
34%5%14%29%14%
1669
16th to endNight
34%5%13%32%13%
1830
October1st to 15thNight
44%411%25%13%
1980
16th to endNight
54%5%13%18%7%
2112
November1st to 15thNight
45%5%14%21%12%1
2374
16th to endNight
54%5%17%17%4
2520
December1st to 15thNight
60%6%14%14%3
2520
16th to endNight
67%6%12%11%3
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
14%29%34%10%8%1
67
16th to endDay
33%25%25%16%
96
February1st to 15thDay
18%26%41%10%3
90
16th to endDay
21%14%45%16%2
84
March1st to 15thDay
21%14%31%24%8%
270
16th to endDay
23%10%31%23%8%2
288
April1st to 15thDay
20%13%33%24%7%
270
16th to endDay
19%10%30%22%11%5%
270
May1st to 15thDay
20%326%26%13%8%
288
16th to endDay
14%6%29%26%17%5%
331
June1st to 15thDay
16%6%22%33%18%2
315
16th to endDay
14%6%27%32%15%3
432
July1st to 15thDay
8%421%36%19%9%
347
16th to endDay
7%224%35%20%8%
326
August1st to 15thDay
8%220%28%24%15%
297
16th to endDay
13%314%26%21%20%
268
September1st to 15thDay
13%317%27%20%17%
255
16th to endDay
18%418%27%21%11%
254
October1st to 15thDay
19%5%30%21%15%6%
255
16th to endDay
27%11%29%23%7%
272
November1st to 15thDay
10%14%30%30%12%3
90
16th to endDay
25%18%26%23%6%
60
December1st to 15thDay
18%16%43%16%5%
60
16th to endDay
29%20%42%7%
64
January1st to 15thNight
26%17%33%17%3
720
16th to endNight
20%11%38%23%6%
768
February1st to 15thNight
20%15%39%19%4
704
16th to endNight
20%13%36%24%5%
631
March1st to 15thNight
23%11%37%24%4
720
16th to endNight
19%10%32%27%9%
768
April1st to 15thNight
22%8%37%26%5%
718
16th to endNight
14%8%33%31%10%1
552
May1st to 15thNight
16%425%34%17%1
504
16th to endNight
12%429%32%20%
375
June1st to 15thNight
13%5%28%35%17%
360
16th to endNight
9%223%45%18%
360
July1st to 15thNight
7%220%46%23%
340
16th to endNight
8%218%46%22%2
503
August1st to 15thNight
7%115%43%28%3
527
16th to endNight
11%118%35%29%3
566
September1st to 15thNight
13%5%21%28%24%5%
660
16th to endNight
14%419%31%26%3
657
October1st to 15thNight
19%5%26%27%17%2
660
16th to endNight
25%10%31%26%4
704
November1st to 15thNight
18%8%32%27%12%1
700
16th to endNight
23%13%29%25%6%
720
December1st to 15thNight
29%12%35%18%3
720
16th to endNight
26%11%37%20%2
768
Page generated at 2017-08-13 14:16:52. Version ac04

Copyright 2017 A. Danko


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