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Mississauga
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mississauga clear sky chart from 2005-11-06 to 2024-01-16.

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
36%
22859
16%
74850
10%
22812
44%
22812
20%
50653

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 10thNight
18%
757
13%
2649
5%
757
28%
757
11%
1980
January11th to 20thNight
17%
741
10%
2433
3%
741
25%
741
10%
1894
January21st to endNight
23%
792
14%
2574
6%
792
33%
792
14%
1875
February1st to 10thNight
15%
720
11%
2340
3%
720
25%
720
12%
1746
February11th to 20thNight
20%
700
14%
2275
4%
700
32%
700
13%
1677
February21st to endNight
20%
592
15%
1862
6%
592
31%
592
16%
1323
March1st to 10thNight
25%
720
18%
1980
7%
720
35%
720
20%
1380
March11th to 20thNight
24%
720
18%
1980
8%
720
33%
720
20%
1408
March21st to endNight
33%
792
21%
2178
11%
792
41%
792
23%
1498
April1st to 10thNight
26%
720
16%
1841
6%
720
32%
720
22%
1309
April11th to 20thNight
32%
654
19%
1718
8%
654
38%
654
25%
1201
April21st to endNight
35%
540
18%
1620
8%
540
43%
540
23%
1094
May1st to 10thNight
43%
540
17%
1620
10%
540
49%
540
26%
1059
May11th to 20thNight
47%
386
24%
1448
19%
386
59%
386
26%
831
May21st to endNight
56%
388
18%
1551
19%
388
64%
388
30%
800
June1st to 10thNight
51%
360
16%
1440
15%
360
62%
360
24%
817
June11th to 20thNight
49%
360
17%
1440
19%
360
59%
360
26%
793
June21st to endNight
56%
360
16%
1419
20%
360
63%
360
27%
790
July1st to 10thNight
68%
350
18%
1400
24%
350
74%
350
36%
672
July11th to 20thNight
61%
348
21%
1392
28%
348
65%
348
31%
726
July21st to endNight
66%
583
19%
1665
17%
551
68%
551
38%
932
August1st to 10thNight
67%
537
18%
1600
14%
534
70%
534
36%
938
August11th to 20thNight
68%
534
25%
1598
19%
534
72%
534
41%
880
August21st to endNight
59%
666
23%
1854
13%
666
62%
666
35%
1117
September1st to 10thNight
56%
720
20%
1800
10%
720
61%
720
37%
1146
September11th to 20thNight
60%
720
29%
1913
17%
720
65%
720
40%
1123
September21st to endNight
50%
720
22%
2010
16%
720
55%
720
29%
1301
October1st to 10thNight
43%
720
19%
2160
16%
720
49%
720
26%
1414
October11th to 20thNight
34%
720
17%
2160
12%
720
43%
720
21%
1495
October21st to endNight
27%
792
17%
2376
11%
792
35%
792
16%
1742
November1st to 10thNight
38%
740
21%
2455
16%
740
47%
740
21%
1585
November11th to 20thNight
27%
760
16%
2660
8%
760
38%
760
17%
1803
November21st to endNight
25%
760
12%
2660
7%
760
33%
760
15%
1896
December1st to 10thNight
19%
760
11%
2660
6%
760
27%
760
12%
1988
December11th to 20thNight
21%
760
9%
3256
3%
758
30%
758
9%
2423
December21st to endNight
15%
827
4%
4863
2%
817
22%
817
5%
3997

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%37%6%45%5%6%7%34%
74678
Night
16%9%47%6%35%5%5%7%35%
75085
TransparencyDay
49%412%22%12%1
74394
Night
50%311%22%12%1
74903
SeeingDay
18%9%28%26%14%6%
13320
Night
19%7%28%30%13%2
22875

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 10thDay
16%12%6%9%8%45%5%7%6%22%
1517
11th to 20thDay
17%15%5%11%8%35%47%7%20%
1636
21st to endDay
13%15%6%12%9%46%5%5%5%21%
1782
February1st to 10thDay
15%13%5%11%8%45%5%5%6%21%
1620
11th to 20thDay
13%14%6%10%7%45%446%27%
1573
21st to endDay
18%13%49%7%35%5%5%5%27%
1388
March1st to 10thDay
13%9%5%9%6%5%6%5%5%7%30%
1977
11th to 20thDay
14%11%5%8%6%35%5%6%432%
1980
21st to endDay
18%9%38%6%46%446%33%
2178
April1st to 10thDay
15%11%48%7%345%5%6%31%
2118
11th to 20thDay
17%9%26%5%35%45%6%37%
2208
21st to endDay
19%7%46%6%35%45%7%34%
2340
May1st to 10thDay
15%8%37%5%45%5%6%8%34%
2340
11th to 20thDay
14%7%35%6%345%5%8%40%
2444
21st to endDay
12%425%6%346%6%8%44%
2725
June1st to 10thDay
13%5%35%6%35%6%6%8%40%
2520
11th to 20thDay
11%5%25%6%36%6%8%9%40%
2520
21st to endDay
12%425%5%35%6%7%9%42%
2520
July1st to 10thDay
7%4246%36%6%7%10%46%
2520
11th to 20thDay
11%425%5%36%6%7%9%41%
2520
21st to endDay
9%5%25%6%47%7%8%11%38%
2551
August1st to 10thDay
8%5%26%6%45%6%7%9%41%
2327
11th to 20thDay
7%6%26%7%46%5%6%10%42%
2303
21st to endDay
10%6%26%5%45%5%6%9%43%
2482
September1st to 10thDay
13%5%25%5%46%6%5%9%41%
2160
11th to 20thDay
11%5%245%35%46%9%46%
2044
21st to endDay
12%6%35%6%46%5%6%9%38%
1949
October1st to 10thDay
18%8%35%6%35%46%7%35%
1800
11th to 20thDay
20%8%47%6%35%5%6%6%29%
1800
21st to endDay
24%10%47%6%446%6%6%23%
1980
November1st to 10thDay
14%8%37%6%45%5%5%8%35%
1618
11th to 20thDay
15%11%37%7%46%6%7%8%28%
1520
21st to endDay
18%12%5%7%7%35%5%5%7%24%
1520
December1st to 10thDay
17%14%6%9%9%46%5%46%19%
1520
11th to 20thDay
20%12%5%8%8%446%5%5%23%
1906
21st to endDay
30%14%6%10%6%4444414%
2772
January1st to 10thNight
18%13%5%9%7%45%5%5%6%23%
2649
11th to 20thNight
20%13%6%10%7%35%5%46%21%
2433
21st to endNight
13%12%6%8%8%46%5%5%6%27%
2574
February1st to 10thNight
15%13%6%9%8%46%5%5%6%24%
2340
11th to 20thNight
14%13%5%9%7%45%6%45%28%
2273
21st to endNight
15%10%49%7%45%5%6%7%28%
1862
March1st to 10thNight
13%8%37%7%46%5%5%6%34%
1970
11th to 20thNight
15%10%5%9%7%3435%5%35%
1979
21st to endNight
16%8%47%5%34445%39%
2178
April1st to 10thNight
18%8%37%6%35%45%6%33%
1841
11th to 20thNight
15%8%36%5%5%5%5%5%6%38%
1718
21st to endNight
17%8%37%5%346%47%37%
1620
May1st to 10thNight
16%7%25%5%35%46%7%39%
1620
11th to 20thNight
15%4245%2445%7%46%
1447
21st to endNight
10%42443446%8%51%
1550
June1st to 10thNight
11%435%445%5%6%8%43%
1440
11th to 20thNight
10%5%26%5%345%6%9%44%
1440
21st to endNight
10%5%35%6%345%6%7%45%
1419
July1st to 10thNight
5%41442445%7%58%
1440
11th to 20thNight
10%324435%46%9%50%
1440
21st to endNight
8%424435%5%7%8%51%
1763
August1st to 10thNight
8%415%5%46%5%6%8%49%
1611
11th to 20thNight
7%415%435%47%9%52%
1598
21st to endNight
10%425%5%35%5%6%7%48%
1854
September1st to 10thNight
9%6%25%5%35%5%7%8%46%
1800
11th to 20thNight
11%424424447%54%
1913
21st to endNight
14%6%36%5%3445%7%43%
2010
October1st to 10thNight
16%7%36%5%245%5%7%40%
2160
11th to 20thNight
18%8%36%6%345%5%6%35%
2160
21st to endNight
22%8%47%6%35%5%5%6%29%
2376
November1st to 10thNight
17%6%26%6%35%45%7%39%
2455
11th to 20thNight
15%10%46%6%46%5%6%7%31%
2660
21st to endNight
20%9%46%6%45%5%5%7%28%
2660
December1st to 10thNight
20%13%5%8%6%35%45%6%25%
2660
11th to 20thNight
16%16%5%9%6%35%6%5%6%23%
3288
21st to endNight
30%14%6%9%6%35%5%45%14%
4884

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 10thDay
62%312%16%7%
1518
11th to 20thDay
64%412%15%6%
1636
21st to endDay
65%38%13%9%1
1782
February1st to 10thDay
64%312%17%41
1620
11th to 20thDay
60%310%16%9%2
1582
21st to endDay
59%39%20%8%1
1388
March1st to 10thDay
53%412%20%10%2
1980
11th to 20thDay
54%39%20%12%2
1980
21st to endDay
53%29%20%13%2
2178
April1st to 10thDay
54%311%19%13%1
2118
11th to 20thDay
48%210%22%16%1
2208
21st to endDay
52%310%20%12%3
2340
May1st to 10thDay
48%311%22%15%1
2340
11th to 20thDay
44%411%26%14%2
2448
21st to endDay
37%317%26%15%2
2725
June1st to 10thDay
41%5%12%25%16%2
2520
11th to 20thDay
38%412%27%17%1
2520
21st to endDay
38%414%28%16%1
2520
July1st to 10thDay
32%5%12%29%19%3
2450
11th to 20thDay
37%414%30%13%1
2445
21st to endDay
39%5%15%25%15%2
2408
August1st to 10thDay
37%417%27%13%2
2314
11th to 20thDay
38%317%28%13%1
2303
21st to endDay
37%5%13%30%14%1
2482
September1st to 10thDay
40%5%14%29%12%1
2160
11th to 20thDay
35%314%32%15%1
2044
21st to endDay
43%415%28%10%
1949
October1st to 10thDay
48%314%22%12%1
1800
11th to 20thDay
55%311%23%7%1
1800
21st to endDay
60%412%17%6%1
1980
November1st to 10thDay
48%413%24%9%1
1618
11th to 20thDay
54%415%16%9%1
1520
21st to endDay
60%314%18%4
1520
December1st to 10thDay
66%312%14%5%
1520
11th to 20thDay
63%314%13%7%
1906
21st to endDay
75%29%12%3
2772
January1st to 10thNight
62%310%18%7%
2649
11th to 20thNight
66%211%14%6%1
2433
21st to endNight
58%311%17%9%1
2574
February1st to 10thNight
60%310%19%6%1
2340
11th to 20thNight
59%39%18%10%1
2275
21st to endNight
56%212%21%9%1
1862
March1st to 10thNight
50%312%22%11%2
1980
11th to 20thNight
53%29%21%12%2
1980
21st to endNight
48%27%23%16%3
2178
April1st to 10thNight
52%29%20%15%1
1841
11th to 20thNight
48%39%21%16%2
1718
21st to endNight
48%49%21%16%3
1620
May1st to 10thNight
45%39%23%18%3
1620
11th to 20thNight
38%410%28%17%4
1448
21st to endNight
32%314%26%20%4
1551
June1st to 10thNight
38%410%26%18%2
1440
11th to 20thNight
37%311%25%22%3
1440
21st to endNight
37%314%26%19%1
1419
July1st to 10thNight
27%311%27%28%4
1400
11th to 20thNight
33%311%32%19%2
1392
21st to endNight
31%315%29%19%3
1665
August1st to 10thNight
34%416%31%14%2
1600
11th to 20thNight
29%315%37%14%2
1598
21st to endNight
36%312%29%18%1
1854
September1st to 10thNight
35%415%30%15%2
1800
11th to 20thNight
31%310%37%18%
1913
21st to endNight
41%313%30%12%1
2010
October1st to 10thNight
44%311%25%15%1
2160
11th to 20thNight
50%311%26%9%
2160
21st to endNight
56%410%18%11%1
2376
November1st to 10thNight
46%310%26%13%1
2455
11th to 20thNight
51%314%20%10%1
2660
21st to endNight
55%416%20%4
2660
December1st to 10thNight
61%311%18%6%
2660
11th to 20thNight
62%313%16%5%
3288
21st to endNight
74%311%9%3
4884

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 10thDay
19%16%31%23%9%1
180
11th to 20thDay
24%19%35%11%9%1
241
21st to endDay
24%13%36%20%6%
264
February1st to 10thDay
26%14%42%14%3
240
11th to 20thDay
21%20%41%17%11
240
21st to endDay
29%22%33%15%
210
March1st to 10thDay
21%12%36%23%8%
420
11th to 20thDay
21%16%31%22%8%1
420
21st to endDay
26%9%32%23%8%1
462
April1st to 10thDay
19%13%33%26%8%1
420
11th to 20thDay
25%12%30%18%10%4
412
21st to endDay
23%10%32%23%10%3
420
May1st to 10thDay
21%8%29%23%12%6%
423
11th to 20thDay
17%5%29%27%15%7%
447
21st to endDay
14%5%24%31%18%8%
485
June1st to 10thDay
12%8%28%33%14%5%
450
11th to 20thDay
16%6%24%29%22%3
450
21st to endDay
14%6%24%30%20%6%
450
July1st to 10thDay
9%119%35%25%11%
445
11th to 20thDay
13%319%32%22%10%
444
21st to endDay
9%223%38%19%8%
488
August1st to 10thDay
11%320%28%26%13%
446
11th to 20thDay
9%419%33%21%15%
439
21st to endDay
12%422%28%22%12%
495
September1st to 10thDay
14%421%31%18%12%
450
11th to 20thDay
10%422%25%24%16%
450
21st to endDay
14%8%29%23%17%9%
450
October1st to 10thDay
22%6%26%22%15%8%
450
11th to 20thDay
21%10%34%23%9%2
450
21st to endDay
28%11%27%25%8%1
495
November1st to 10thDay
19%16%27%24%11%2
266
11th to 20thDay
24%18%30%20%7%2
180
21st to endDay
23%10%42%19%6%1
180
December1st to 10thDay
26%13%35%21%5%1
180
11th to 20thDay
28%19%32%17%4
180
21st to endDay
26%16%37%17%4
198
January1st to 10thNight
24%13%34%22%6%1
760
11th to 20thNight
30%10%30%24%5%
741
21st to endNight
19%8%37%28%7%1
792
February1st to 10thNight
23%13%38%22%3
720
11th to 20thNight
23%12%36%24%5%
703
21st to endNight
20%12%41%24%3
592
March1st to 10thNight
18%12%36%27%7%
720
11th to 20thNight
22%9%36%24%8%1
720
21st to endNight
20%10%29%31%9%1
792
April1st to 10thNight
22%9%33%30%6%
720
11th to 20thNight
19%8%35%25%10%2
654
21st to endNight
21%5%27%35%11%
540
May1st to 10thNight
19%327%32%17%2
540
11th to 20thNight
16%323%42%14%1
386
21st to endNight
11%224%37%25%1
389
June1st to 10thNight
13%323%42%19%1
360
11th to 20thNight
10%427%39%19%1
360
21st to endNight
11%319%44%21%1
360
July1st to 10thNight
7%118%46%26%3
350
11th to 20thNight
12%120%40%24%3
348
21st to endNight
9%215%46%25%3
583
August1st to 10thNight
9%211%44%30%4
537
11th to 20thNight
7%312%43%31%4
534
21st to endNight
11%218%36%28%4
666
September1st to 10thNight
12%5%19%35%23%6%
720
11th to 20thNight
13%316%32%29%6%
720
21st to endNight
17%420%31%23%4
720
October1st to 10thNight
19%325%27%22%3
720
11th to 20thNight
22%8%28%30%10%2
720
21st to endNight
27%8%28%31%6%
792
November1st to 10thNight
20%9%26%32%12%1
740
11th to 20thNight
22%9%33%25%9%2
760
21st to endNight
26%8%32%27%7%
760
December1st to 10thNight
28%10%34%22%6%
760
11th to 20thNight
25%10%37%23%5%
760
21st to endNight
31%9%34%22%3
836
Page generated at 2024-01-13 01:38:08. Version ac07

Copyright 2024 Attilla Danko


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