Toronto(KS)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Toronto(KS) clear sky chart from 2005-11-05 to 2017-12-02.

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
44%
16148
22%
47820
13%
16102
52%
16102
34%
27787

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
34%
899
25%
2327
10%
895
44%
895
37%
1407
January16th to endNight
35%
960
24%
2496
9%
960
44%
960
39%
1468
February1st to 15thNight
30%
880
19%
2288
6%
876
37%
876
29%
1489
February16th to endNight
30%
629
21%
1891
7%
629
41%
629
31%
1103
March1st to 15thNight
33%
540
21%
1980
11%
540
45%
540
26%
1143
March16th to endNight
27%
576
15%
2112
10%
576
35%
576
21%
1311
April1st to 15thNight
32%
539
19%
1899
11%
539
46%
539
27%
1056
April16th to endNight
32%
540
15%
1670
10%
540
41%
540
27%
1050
May1st to 15thNight
38%
540
19%
1620
13%
540
47%
540
30%
1005
May16th to endNight
49%
563
15%
1684
14%
561
54%
561
31%
1029
June1st to 15thNight
60%
540
15%
1620
10%
540
64%
540
38%
909
June16th to endNight
58%
540
18%
1620
11%
540
64%
540
47%
828
July1st to 15thNight
69%
510
17%
1530
15%
510
71%
510
40%
843
July16th to endNight
77%
564
21%
1594
22%
531
77%
531
41%
867
August1st to 15thNight
76%
539
23%
1610
27%
536
78%
536
41%
885
August16th to endNight
75%
573
24%
1785
27%
573
77%
573
42%
950
September1st to 15thNight
61%
540
23%
1927
26%
540
65%
540
32%
1051
September16th to endNight
62%
537
27%
1980
25%
537
68%
537
36%
998
October1st to 15thNight
45%
672
27%
2112
19%
672
50%
672
32%
1225
October16th to endNight
41%
768
30%
2304
15%
768
52%
768
44%
1166
November1st to 15thNight
40%
854
28%
2374
13%
854
50%
854
39%
1343
November16th to endNight
37%
975
25%
2535
10%
975
46%
975
36%
1544
December1st to 15thNight
33%
910
19%
2366
9%
910
40%
910
33%
1503
December16th to endNight
35%
960
22%
2496
11%
960
43%
960
31%
1614

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
9%4143217%346%41%
48626
Night
8%4133217%345%45%
48016
Cloud CoverDay
11%5%2442445%7%47%
48624
Night
10%424323447%52%
48016
TransparencyDay
36%6%12%25%16%2
48324
Night
31%5%12%26%19%4
47821
SeeingDay
13%6%25%29%20%4
6083
Night
12%8%31%33%13%1
16149

By Month

Percentage Cloud Cover SW (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
7%6%143320%22443%
1611
16th to endDay
9%5%25%3219%23442%
1728
February1st to 15thDay
9%6%36%4219%235%38%
1575
16th to endDay
9%6%244218%33440%
1590
March1st to 15thDay
11%6%244219%335%35%
1980
16th to endDay
17%6%243119%33434%
2112
April1st to 15thDay
11%5%144219%345%36%
2049
16th to endDay
16%6%25%4219%33431%
2288
May1st to 15thDay
12%5%144220%245%35%
2331
16th to endDay
13%415%4320%5%45%30%
2430
June1st to 15thDay
7%3134219%347%40%
2340
16th to endDay
3123119%35%8%48%
2340
July1st to 15thDay
7%2133220%45%8%40%
2340
16th to endDay
43133320%6%5%7%41%
2466
August1st to 15thDay
6%3133213%35%8%46%
2340
16th to endDay
6%3143211%447%49%
2417
September1st to 15thDay
13%4244211%345%44%
2030
16th to endDay
8%3143211%346%50%
1980
October1st to 15thDay
10%6%134211%34447%
1834
16th to endDay
8%343210%25%5%53%
1920
November1st to 15thDay
7%4132115%345%49%
1811
16th to endDay
10%3122117%22450%
1755
December1st to 15thDay
13%6%243218%325%36%
1631
16th to endDay
12%6%244118%235%37%
1728
January1st to 15thNight
7%5%132219%245%44%
2327
16th to endNight
6%4143218%33447%
2496
February1st to 15thNight
8%6%243219%32442%
2278
16th to endNight
9%5%133118%245%43%
1891
March1st to 15thNight
11%4134219%345%39%
1980
16th to endNight
13%5%233119%23439%
2112
April1st to 15thNight
9%4143219%345%43%
1899
16th to endNight
12%5%144219%24437%
1670
May1st to 15thNight
11%4232118%346%41%
1619
16th to endNight
9%3143219%349%37%
1683
June1st to 15thNight
42123220%447%45%
1620
16th to endNight
1122120%45%7%50%
1620
July1st to 15thNight
5%2133219%35%7%45%
1620
16th to endNight
3225%320%45%7%42%
1702
August1st to 15thNight
32134212%5%6%8%49%
1620
16th to endNight
5%2133211%345%55%
1785
September1st to 15thNight
10%3133211%345%49%
1927
16th to endNight
7%3133111%45%6%51%
1980
October1st to 15thNight
13%4143210%23448%
2112
16th to endNight
6%2122110%335%58%
2304
November1st to 15thNight
8%3132116%33451%
2374
16th to endNight
11%3132117%23447%
2535
December1st to 15thNight
13%5%132118%335%39%
2366
16th to endNight
11%5%233219%23440%
2496

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
9%7%1443433452%
1611
16th to endDay
11%5%36%423246%49%
1728
February1st to 15thDay
10%7%47%423345%45%
1575
16th to endDay
10%7%25%5%2335%6%47%
1590
March1st to 15thDay
13%8%35%424446%41%
1980
16th to endDay
20%8%35%423335%39%
2110
April1st to 15thDay
13%5%36%424347%44%
2049
16th to endDay
18%8%25%424345%39%
2288
May1st to 15thDay
16%7%35%5%35%35%6%38%
2331
16th to endDay
15%5%26%5%35%5%5%7%36%
2430
June1st to 15thDay
9%4245%3446%8%47%
2340
16th to endDay
6%21232445%10%55%
2340
July1st to 15thDay
8%324425%47%10%46%
2340
16th to endDay
5%324435%6%6%9%48%
2466
August1st to 15thDay
6%4135%25%5%6%9%48%
2340
16th to endDay
7%41442446%8%51%
2417
September1st to 15thDay
13%5%24423346%47%
2030
16th to endDay
9%324323347%54%
1980
October1st to 15thDay
11%6%1442335%5%51%
1834
16th to endDay
10%31341325%6%56%
1920
November1st to 15thDay
9%41332335%7%56%
1811
16th to endDay
12%423312225%58%
1755
December1st to 15thDay
15%6%35%422436%45%
1631
16th to endDay
16%6%36%413247%43%
1728
January1st to 15thNight
8%5%23324346%53%
2327
16th to endNight
7%5%2441434456%
2496
February1st to 15thNight
9%7%26%424435%48%
2278
16th to endNight
9%5%3441335%6%51%
1891
March1st to 15thNight
11%5%2442345%7%47%
1980
16th to endNight
17%6%34423346%44%
2112
April1st to 15thNight
10%5%14424447%51%
1899
16th to endNight
14%6%25%423346%46%
1670
May1st to 15thNight
14%5%2431245%8%46%
1619
16th to endNight
10%5%25%42446%10%45%
1683
June1st to 15thNight
5%2243246%49%53%
1620
16th to endNight
323315%5%6%10%57%
1620
July1st to 15thNight
6%31442446%9%52%
1620
16th to endNight
42135%35%46%10%51%
1702
August1st to 15thNight
43134245%7%9%51%
1620
16th to endNight
5%31342445%7%57%
1785
September1st to 15thNight
11%424423446%52%
1927
16th to endNight
8%31332345%7%56%
1980
October1st to 15thNight
14%5%1432224453%
2112
16th to endNight
8%312312346%62%
2304
November1st to 15thNight
9%413223336%58%
2374
16th to endNight
12%5%22312335%55%
2535
December1st to 15thNight
14%6%24313446%48%
2366
16th to endNight
13%7%34423346%47%
2496

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
35%412%27%19%1
1612
16th to endDay
37%213%27%16%1
1728
February1st to 15thDay
41%5%14%27%9%2
1576
16th to endDay
37%412%26%15%3
1590
March1st to 15thDay
43%5%9%23%14%3
1980
16th to endDay
48%5%10%23%10%1
2112
April1st to 15thDay
38%5%14%23%15%1
2049
16th to endDay
47%410%23%12%1
2288
May1st to 15thDay
46%6%11%20%13%1
2331
16th to endDay
45%8%13%21%10%1
2434
June1st to 15thDay
33%7%13%25%17%2
2340
16th to endDay
24%7%15%29%20%3
2340
July1st to 15thDay
31%8%15%27%15%1
2201
16th to endDay
27%8%16%30%15%1
2311
August1st to 15thDay
29%9%16%24%17%2
2326
16th to endDay
29%6%13%27%15%6%
2417
September1st to 15thDay
37%6%10%22%16%6%
2030
16th to endDay
29%5%10%28%22%3
1980
October1st to 15thDay
33%5%11%22%21%4
1834
16th to endDay
28%5%11%26%22%6%
1920
November1st to 15thDay
27%5%11%28%20%6%
1811
16th to endDay
29%210%29%24%2
1755
December1st to 15thDay
40%5%11%28%14%
1631
16th to endDay
42%411%24%13%3
1728
January1st to 15thNight
31%410%29%20%3
2327
16th to endNight
29%313%29%18%4
2496
February1st to 15thNight
38%413%26%14%2
2288
16th to endNight
33%412%28%17%4
1891
March1st to 15thNight
35%5%11%22%18%6%
1980
16th to endNight
42%5%12%21%15%2
2112
April1st to 15thNight
33%5%10%25%21%4
1899
16th to endNight
40%413%20%17%3
1670
May1st to 15thNight
36%6%15%22%17%2
1620
16th to endNight
33%7%18%24%14%1
1685
June1st to 15thNight
26%6%16%29%17%1
1620
16th to endNight
19%6%15%33%20%3
1620
July1st to 15thNight
27%5%13%30%20%3
1530
16th to endNight
25%6%13%27%24%1
1594
August1st to 15thNight
24%7%14%30%17%4
1610
16th to endNight
24%6%12%26%22%7%
1785
September1st to 15thNight
31%412%23%18%8%
1927
16th to endNight
25%5%11%27%25%4
1980
October1st to 15thNight
35%39%19%23%8%
2112
16th to endNight
22%38%29%28%6%
2304
November1st to 15thNight
27%410%26%22%8%
2374
16th to endNight
32%48%27%23%4
2535
December1st to 15thNight
36%414%28%16%
2366
16th to endNight
39%312%24%14%5%
2496

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
28%11%31%20%8%
90
16th to endDay
15%16%40%19%6%1
96
February1st to 15thDay
8%24%42%18%5%
90
16th to endDay
7%23%40%20%6%1
81
March1st to 15thDay
20%25%42%10%2
90
16th to endDay
21%13%40%19%31
96
April1st to 15thDay
17%11%38%26%6%
168
16th to endDay
22%12%36%17%9%1
398
May1st to 15thDay
17%11%31%25%11%2
468
16th to endDay
19%7%32%25%12%2
517
June1st to 15thDay
10%326%35%21%3
495
16th to endDay
6%325%40%19%3
495
July1st to 15thDay
10%118%37%26%5%
475
16th to endDay
6%8%31%43%9%
515
August1st to 15thDay
7%111%33%38%7%
493
16th to endDay
8%116%31%34%7%
457
September1st to 15thDay
10%29%31%35%9%
185
16th to endDay
13%120%40%13%10%
135
October1st to 15thDay
11%5%36%26%10%9%
135
16th to endDay
9%6%41%31%9%1
144
November1st to 15thDay
20%5%25%26%16%4
135
16th to endDay
24%14%32%20%6%
135
December1st to 15thDay
15%13%42%17%7%3
94
16th to endDay
22%15%31%25%5%
96
January1st to 15thNight
12%13%36%29%7%
900
16th to endNight
10%11%39%32%6%
960
February1st to 15thNight
13%13%38%30%3
880
16th to endNight
12%13%40%28%4
629
March1st to 15thNight
14%10%39%28%7%
540
16th to endNight
20%10%39%24%4
576
April1st to 15thNight
12%14%37%29%5%
539
16th to endNight
18%8%38%26%7%
540
May1st to 15thNight
18%5%35%29%10%
540
16th to endNight
11%5%30%33%16%1
563
June1st to 15thNight
6%425%41%22%
540
16th to endNight
5%131%44%17%
540
July1st to 15thNight
8%116%48%23%1
510
16th to endNight
5%8%42%39%3
564
August1st to 15thNight
5%9%46%35%1
539
16th to endNight
6%12%38%39%2
573
September1st to 15thNight
12%18%41%24%2
540
16th to endNight
9%320%37%23%5%
537
October1st to 15thNight
17%429%28%17%2
672
16th to endNight
10%8%38%30%11%
768
November1st to 15thNight
12%10%34%29%11%1
854
16th to endNight
15%12%33%30%8%
975
December1st to 15thNight
18%10%34%31%5%
910
16th to endNight
17%9%34%32%5%
960
Page generated at 2017-12-03 10:16:46. Version ac04

Copyright 2017 A. Danko


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