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 2017-03-31.

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%
15333
21%
45326
13%
15287
51%
15287
34%
26376

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%
494
21%
1741
12%
494
47%
494
27%
966
April16th to endNight
33%
495
14%
1531
9%
495
42%
495
28%
949
May1st to 15thNight
37%
495
20%
1485
13%
495
47%
495
29%
928
May16th to endNight
49%
515
13%
1540
12%
513
53%
513
30%
946
June1st to 15thNight
59%
495
16%
1485
11%
495
63%
495
38%
833
June16th to endNight
60%
495
16%
1485
10%
495
65%
495
48%
753
July1st to 15thNight
67%
465
18%
1395
15%
465
70%
465
40%
771
July16th to endNight
77%
522
19%
1468
20%
489
77%
489
41%
798
August1st to 15thNight
77%
494
24%
1475
28%
491
79%
491
42%
807
August16th to endNight
75%
525
22%
1635
25%
525
76%
525
42%
871
September1st to 15thNight
60%
495
24%
1766
27%
495
63%
495
30%
989
September16th to endNight
61%
492
25%
1815
23%
492
68%
492
36%
908
October1st to 15thNight
46%
616
28%
1936
20%
616
52%
616
33%
1112
October16th to endNight
40%
704
28%
2112
13%
704
51%
704
44%
1079
November1st to 15thNight
41%
787
29%
2187
13%
787
52%
787
40%
1215
November16th to endNight
37%
900
23%
2340
9%
900
46%
900
36%
1427
December1st to 15thNight
32%
900
19%
2340
9%
900
40%
900
33%
1489
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%4143218%345%40%
45755
Night
8%4133217%345%45%
45522
Cloud CoverDay
11%5%2442445%7%47%
45753
Night
10%424323447%52%
45522
TransparencyDay
36%6%12%25%16%2
45453
Night
31%5%12%26%19%4
45327
SeeingDay
13%6%26%29%20%4
5078
Night
12%8%31%33%13%1
15334

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%
2106
April1st to 15thDay
11%5%143221%335%36%
1877
16th to endDay
15%6%25%4220%33431%
2097
May1st to 15thDay
12%5%144221%245%33%
2136
16th to endDay
13%4144322%445%28%
2222
June1st to 15thDay
8%3134321%347%38%
2145
16th to endDay
3123121%35%8%47%
2145
July1st to 15thDay
7%2233221%45%8%38%
2145
16th to endDay
43133322%5%5%6%40%
2284
August1st to 15thDay
6%3123214%35%8%46%
2145
16th to endDay
7%3133212%447%48%
2215
September1st to 15thDay
14%4244212%346%41%
1861
16th to endDay
7%3243212%346%50%
1815
October1st to 15thDay
10%6%144212%245%46%
1681
16th to endDay
8%3143211%25%5%51%
1760
November1st to 15thDay
6%322117%345%51%
1669
16th to endDay
11%3122118%22449%
1620
December1st to 15thDay
13%6%243219%325%36%
1620
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
8%4143221%33443%
1741
16th to endNight
11%5%143220%23438%
1531
May1st to 15thNight
11%3232120%346%39%
1484
16th to endNight
9%3133221%348%36%
1539
June1st to 15thNight
42123221%447%45%
1485
16th to endNight
1122121%45%7%50%
1485
July1st to 15thNight
5%2133221%35%7%44%
1485
16th to endNight
3224322%5%5%6%42%
1576
August1st to 15thNight
32133213%5%6%8%49%
1485
16th to endNight
5%223212%345%55%
1635
September1st to 15thNight
11%4143211%445%46%
1766
16th to endNight
7%3133112%446%51%
1815
October1st to 15thNight
13%4133210%23449%
1936
16th to endNight
6%3122111%335%57%
2112
November1st to 15thNight
6%3132117%33452%
2187
16th to endNight
11%3122118%23347%
2340
December1st to 15thNight
13%5%132119%335%39%
2340
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%
2104
April1st to 15thDay
13%6%35%324447%44%
1877
16th to endDay
17%8%25%424345%40%
2097
May1st to 15thDay
17%7%35%5%35%35%7%36%
2136
16th to endDay
16%6%26%5%35%5%5%7%35%
2222
June1st to 15thDay
9%4245%35%46%8%45%
2145
16th to endDay
6%21232446%10%54%
2145
July1st to 15thDay
9%324425%47%10%44%
2145
16th to endDay
5%324435%6%6%9%48%
2284
August1st to 15thDay
6%313435%5%6%9%49%
2145
16th to endDay
8%41442446%8%51%
2215
September1st to 15thDay
14%5%245%2345%6%45%
1861
16th to endDay
8%324323346%55%
1815
October1st to 15thDay
11%6%1442325%5%51%
1681
16th to endDay
10%41441325%6%55%
1760
November1st to 15thDay
8%31332335%7%58%
1669
16th to endDay
13%423312235%58%
1620
December1st to 15thDay
15%6%35%422436%45%
1620
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%24424447%51%
1741
16th to endNight
13%6%25%423336%47%
1531
May1st to 15thNight
14%5%2431345%8%45%
1484
16th to endNight
10%5%25%43446%10%44%
1539
June1st to 15thNight
5%2233346%49%53%
1485
16th to endNight
3133145%6%10%58%
1485
July1st to 15thNight
7%31442446%9%52%
1485
16th to endNight
4213436%46%9%51%
1576
August1st to 15thNight
43134245%7%10%52%
1485
16th to endNight
5%31342445%7%57%
1635
September1st to 15thNight
12%42442345%6%49%
1766
16th to endNight
7%31332445%7%56%
1815
October1st to 15thNight
13%5%1432334453%
1936
16th to endNight
8%312312346%61%
2112
November1st to 15thNight
8%413223335%60%
2187
16th to endNight
12%5%22312335%55%
2340
December1st to 15thNight
15%6%24313346%48%
2340
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
2106
April1st to 15thDay
38%5%13%24%15%1
1877
16th to endDay
45%410%24%12%1
2097
May1st to 15thDay
48%6%11%20%12%1
2136
16th to endDay
46%8%14%20%10%1
2226
June1st to 15thDay
34%8%14%23%16%2
2145
16th to endDay
24%7%15%28%20%3
2145
July1st to 15thDay
32%8%15%26%14%1
2006
16th to endDay
28%8%15%31%14%1
2129
August1st to 15thDay
28%9%16%25%18%2
2131
16th to endDay
30%6%14%27%13%7%
2215
September1st to 15thDay
39%6%10%20%15%7%
1861
16th to endDay
29%5%10%27%23%3
1815
October1st to 15thDay
33%5%11%23%21%4
1681
16th to endDay
29%5%12%26%21%5%
1760
November1st to 15thDay
25%5%11%29%21%7%
1669
16th to endDay
30%211%29%23%2
1620
December1st to 15thDay
40%5%11%28%14%
1620
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%410%25%22%4
1741
16th to endNight
38%413%21%17%3
1531
May1st to 15thNight
36%6%15%22%16%2
1485
16th to endNight
34%7%18%23%13%1
1541
June1st to 15thNight
27%6%17%29%17%1
1485
16th to endNight
19%6%15%34%20%4
1485
July1st to 15thNight
27%5%13%29%20%3
1395
16th to endNight
24%7%14%27%24%1
1468
August1st to 15thNight
24%7%14%30%18%5%
1475
16th to endNight
24%6%13%27%20%7%
1635
September1st to 15thNight
33%5%13%20%18%9%
1766
16th to endNight
25%5%11%25%27%4
1815
October1st to 15thNight
34%39%20%23%8%
1936
16th to endNight
23%39%30%27%5%
2112
November1st to 15thNight
26%49%26%24%8%
2187
16th to endNight
32%48%27%22%4
2340
December1st to 15thNight
36%413%28%16%
2340
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%41%19%31
94
April1st to 15thDay
18%9%35%30%6%
116
16th to endDay
19%12%38%17%10%1
327
May1st to 15thDay
19%10%33%24%10%1
393
16th to endDay
21%5%31%24%13%3
437
June1st to 15thDay
10%427%36%19%2
420
16th to endDay
6%225%40%21%4
420
July1st to 15thDay
11%220%38%23%3
400
16th to endDay
6%19%33%41%8%
445
August1st to 15thDay
7%110%33%38%8%
418
16th to endDay
9%216%29%34%7%
383
September1st to 15thDay
13%211%33%32%6%
136
16th to endDay
12%221%32%16%15%
90
October1st to 15thDay
7%6%25%33%13%13%
90
16th to endDay
6%342%35%10%2
96
November1st to 15thDay
11%325%31%22%6%
90
16th to endDay
33%15%28%18%21
90
December1st to 15thDay
16%14%42%16%6%3
90
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%15%37%29%6%
494
16th to endNight
17%8%38%27%7%
495
May1st to 15thNight
18%5%36%29%10%
495
16th to endNight
11%5%31%33%17%2
515
June1st to 15thNight
6%426%41%21%
495
16th to endNight
5%130%44%18%
495
July1st to 15thNight
8%117%46%23%1
465
16th to endNight
5%8%42%39%3
522
August1st to 15thNight
5%9%46%36%1
494
16th to endNight
7%12%36%40%2
525
September1st to 15thNight
13%18%40%24%2
495
16th to endNight
9%419%36%24%5%
492
October1st to 15thNight
16%5%28%29%18%2
616
16th to endNight
11%7%39%28%12%
704
November1st to 15thNight
10%10%34%29%12%1
787
16th to endNight
15%13%32%29%9%
900
December1st to 15thNight
18%10%34%31%5%
900
16th to endNight
17%9%34%32%5%
960
Page generated at 2017-04-01 07:23:20. Version ac04

Copyright 2017 A. Danko


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