Owen Sound
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Owen Sound 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
31%
15746
10%
48712
7%
15710
34%
15710
14%
37062

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
11%
970
2%
2841
1%
970
12%
970
4%
2582
January16th to endNight
17%
842
3%
2714
2%
842
18%
842
5%
2399
February1st to 15thNight
16%
757
4%
2468
1%
757
19%
757
5%
2142
February16th to endNight
20%
631
8%
1982
3%
631
26%
631
9%
1602
March1st to 15thNight
22%
720
11%
2016
6%
720
26%
720
14%
1575
March16th to endNight
35%
768
18%
2112
11%
768
40%
768
22%
1487
April1st to 15thNight
28%
673
14%
1808
6%
673
33%
673
20%
1295
April16th to endNight
37%
540
18%
1620
11%
540
42%
540
21%
1120
May1st to 15thNight
45%
528
15%
1608
13%
528
49%
528
23%
1076
May16th to endNight
48%
374
15%
1497
14%
374
58%
374
23%
883
June1st to 15thNight
47%
360
12%
1308
11%
360
53%
360
22%
817
June16th to endNight
54%
360
13%
1260
15%
360
58%
360
26%
771
July1st to 15thNight
63%
340
17%
1190
21%
340
66%
340
35%
632
July16th to endNight
60%
528
14%
1519
14%
495
61%
495
29%
924
August1st to 15thNight
59%
539
16%
1609
12%
536
63%
536
29%
1004
August16th to endNight
58%
576
19%
1722
14%
576
61%
576
29%
1073
September1st to 15thNight
53%
720
16%
1866
9%
720
56%
720
31%
1247
September16th to endNight
52%
717
19%
1980
14%
717
54%
717
27%
1326
October1st to 15thNight
34%
720
13%
2148
11%
720
38%
720
17%
1592
October16th to endNight
22%
768
8%
2340
5%
768
26%
768
10%
1911
November1st to 15thNight
23%
760
11%
2569
10%
760
27%
760
11%
2004
November16th to endNight
18%
780
6%
2730
5%
780
20%
780
7%
2288
December1st to 15thNight
9%
780
1%
2730
0%
780
11%
780
3%
2503
December16th to endNight
8%
995
3%
3075
0%
995
10%
995
3%
2809

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
17%10%47%5%34446%30%
49358
Night
16%12%5%9%6%34445%27%
48883
Cloud CoverDay
16%10%47%6%34446%29%
49368
Night
16%12%5%9%6%34445%27%
48887
TransparencyDay
53%6%11%17%9%
49047
Night
58%6%10%15%8%
48712
SeeingDay
20%7%26%26%14%5%
6194
Night
21%10%28%26%11%1
15755

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
17%18%10%15%10%433338%
1426
16th to endDay
13%20%9%14%10%5%5%4339%
1859
February1st to 15thDay
14%17%9%15%10%5%5%33410%
1695
16th to endDay
16%18%8%11%7%5%5%33414%
1488
March1st to 15thDay
14%11%5%10%7%45%445%26%
1933
16th to endDay
14%8%5%7%6%345%5%7%32%
2112
April1st to 15thDay
21%11%46%423445%31%
2151
16th to endDay
18%9%35%32335%6%37%
2340
May1st to 15thDay
18%7%24423446%39%
2341
16th to endDay
14%6%25%42435%7%42%
2618
June1st to 15thDay
16%6%24435%45%8%38%
2649
16th to endDay
14%5%25%4446%5%8%38%
2700
July1st to 15thDay
12%5%2443446%7%43%
2700
16th to endDay
12%5%244345%6%10%40%
2539
August1st to 15thDay
13%6%15%5%35%46%8%41%
2340
16th to endDay
14%6%245%25%5%5%7%39%
2467
September1st to 15thDay
18%7%35%42435%6%38%
2091
16th to endDay
18%7%25%424448%38%
1980
October1st to 15thDay
23%9%36%5%34446%29%
1812
16th to endDay
34%11%37%5%23435%17%
1881
November1st to 15thDay
19%17%5%7%5%34446%22%
1619
16th to endDay
22%19%6%10%6%25%345%14%
1560
December1st to 15thDay
16%25%10%14%7%333347%
1560
16th to endDay
19%24%10%13%6%343347%
1497
January1st to 15thNight
18%18%8%17%9%342348%
2841
16th to endNight
13%17%9%14%10%45%44410%
2714
February1st to 15thNight
12%16%8%16%10%45%43313%
2466
16th to endNight
14%14%7%13%7%44435%19%
1982
March1st to 15thNight
14%13%6%9%8%34445%25%
2004
16th to endNight
15%10%47%5%2334438%
2112
April1st to 15thNight
20%10%36%424346%33%
1808
16th to endNight
18%9%35%5%23345%36%
1620
May1st to 15thNight
17%6%345%44348%37%
1608
16th to endNight
12%5%25%5%246%5%7%42%
1495
June1st to 15thNight
14%6%35%5%35%46%7%39%
1308
16th to endNight
12%5%235%35%5%5%9%43%
1260
July1st to 15thNight
9%325%31336%8%51%
1260
16th to endNight
9%315%425%6%6%8%45%
1625
August1st to 15thNight
10%5%25%435%46%8%44%
1620
16th to endNight
10%5%25%5%2445%5%47%
1722
September1st to 15thNight
15%5%134245%7%7%42%
1866
16th to endNight
15%5%25%5%24347%41%
1980
October1st to 15thNight
22%8%26%6%34346%31%
2148
16th to endNight
28%12%36%6%34435%20%
2340
November1st to 15thNight
20%15%37%6%34445%23%
2569
16th to endNight
22%16%6%9%7%34346%16%
2730
December1st to 15thNight
18%25%10%12%7%243348%
2730
16th to endNight
19%20%12%13%7%343338%
3075

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
17%18%10%16%10%443328%
1426
16th to endDay
12%20%9%15%10%46%4238%
1859
February1st to 15thDay
13%18%9%16%8%45%34311%
1695
16th to endDay
16%18%9%11%7%5%5%42315%
1488
March1st to 15thDay
14%11%5%11%8%45%43426%
1944
16th to endDay
14%8%5%8%5%35%446%31%
2111
April1st to 15thDay
21%12%46%323345%31%
2151
16th to endDay
18%8%44423346%37%
2340
May1st to 15thDay
19%7%24424446%39%
2341
16th to endDay
14%6%245%3435%7%41%
2618
June1st to 15thDay
16%5%3443446%8%37%
2649
16th to endDay
14%5%345%35%5%6%8%38%
2700
July1st to 15thDay
12%5%25%435%45%8%42%
2700
16th to endDay
12%5%245%35%46%9%40%
2539
August1st to 15thDay
13%5%145%35%46%8%40%
2340
16th to endDay
13%6%25%6%345%5%7%38%
2467
September1st to 15thDay
17%7%35%5%24346%38%
2091
16th to endDay
18%6%25%42345%7%38%
1980
October1st to 15thDay
22%9%35%5%33445%30%
1812
16th to endDay
33%12%48%424435%16%
1881
November1st to 15thDay
19%15%5%7%6%34445%23%
1619
16th to endDay
21%19%6%10%7%24435%13%
1560
December1st to 15thDay
16%25%11%14%7%233247%
1560
16th to endDay
18%25%9%13%8%343237%
1497
January1st to 15thNight
18%18%8%15%10%343338%
2841
16th to endNight
12%17%9%15%9%46%44410%
2714
February1st to 15thNight
12%16%8%16%10%45%43313%
2459
16th to endNight
14%14%6%13%8%34435%19%
1982
March1st to 15thNight
14%14%5%10%8%3444425%
2016
16th to endNight
14%10%47%5%2334437%
2112
April1st to 15thNight
20%11%36%424347%32%
1808
16th to endNight
17%10%345%23345%36%
1620
May1st to 15thNight
17%7%25%435%347%37%
1607
16th to endNight
12%425%5%25%46%7%41%
1495
June1st to 15thNight
14%436%4345%5%7%39%
1308
16th to endNight
11%4245%245%6%8%43%
1260
July1st to 15thNight
9%41441345%9%51%
1260
16th to endNight
8%314435%5%7%8%45%
1625
August1st to 15thNight
10%5%245%345%6%7%45%
1620
16th to endNight
10%5%25%4335%46%47%
1722
September1st to 15thNight
16%2244245%6%8%42%
1866
16th to endNight
15%5%25%5%24347%41%
1980
October1st to 15thNight
22%7%26%6%33346%31%
2148
16th to endNight
28%12%37%6%34445%19%
2340
November1st to 15thNight
21%14%37%6%34445%23%
2569
16th to endNight
21%17%6%8%6%34445%17%
2730
December1st to 15thNight
18%24%10%11%7%343339%
2730
16th to endNight
19%21%10%14%6%443338%
3075

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
82%5%7%4
1427
16th to endDay
80%5%6%5%1
1859
February1st to 15thDay
77%6%7%7%
1697
16th to endDay
72%5%9%8%4
1488
March1st to 15thDay
59%5%11%16%6%
1944
16th to endDay
50%5%12%16%12%1
2112
April1st to 15thDay
53%410%20%10%
2151
16th to endDay
46%5%10%21%14%1
2340
May1st to 15thDay
45%5%10%22%13%2
2341
16th to endDay
40%5%13%23%15%1
2622
June1st to 15thDay
41%7%12%23%14%
2649
16th to endDay
40%8%14%23%12%
2700
July1st to 15thDay
36%6%14%24%15%2
2541
16th to endDay
37%7%14%26%12%1
2382
August1st to 15thDay
38%7%16%22%13%
2327
16th to endDay
41%7%16%22%10%1
2467
September1st to 15thDay
46%6%12%23%10%
2091
16th to endDay
43%7%12%26%8%
1980
October1st to 15thDay
55%5%10%18%9%
1812
16th to endDay
70%5%11%9%3
1881
November1st to 15thDay
62%7%12%11%5%
1619
16th to endDay
73%7%11%6%1
1560
December1st to 15thDay
81%6%7%3
1560
16th to endDay
83%5%7%4
1497
January1st to 15thNight
81%5%8%4
2841
16th to endNight
77%5%9%5%1
2714
February1st to 15thNight
75%5%8%8%1
2468
16th to endNight
66%6%10%10%6%
1982
March1st to 15thNight
60%5%10%16%6%
2016
16th to endNight
49%410%18%15%2
2112
April1st to 15thNight
52%410%20%12%
1808
16th to endNight
49%47%17%18%2
1620
May1st to 15thNight
46%49%21%15%2
1608
16th to endNight
39%5%12%25%14%2
1497
June1st to 15thNight
42%5%12%23%14%1
1308
16th to endNight
37%7%13%26%14%
1260
July1st to 15thNight
28%5%13%29%20%2
1190
16th to endNight
33%8%14%24%17%1
1519
August1st to 15thNight
35%8%16%23%14%1
1609
16th to endNight
36%7%14%27%12%1
1722
September1st to 15thNight
37%8%14%27%11%
1866
16th to endNight
41%6%14%27%10%
1980
October1st to 15thNight
53%7%9%19%10%
2148
16th to endNight
67%5%12%11%3
2340
November1st to 15thNight
62%6%12%13%41
2569
16th to endNight
70%7%12%8%1
2730
December1st to 15thNight
81%7%7%3
2730
16th to endNight
82%5%7%4
3075

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
19%18%40%17%2
106
16th to endDay
34%9%33%20%2
144
February1st to 15thDay
26%21%36%15%
130
16th to endDay
25%20%29%22%1
81
March1st to 15thDay
18%14%36%22%6%
234
16th to endDay
22%7%26%28%11%2
288
April1st to 15thDay
24%7%33%23%8%2
270
16th to endDay
26%5%28%19%14%5%
270
May1st to 15thDay
23%325%28%14%5%
288
16th to endDay
19%5%26%24%18%5%
331
June1st to 15thDay
15%6%27%27%18%3
444
16th to endDay
14%5%31%31%13%3
495
July1st to 15thDay
15%422%34%16%6%
475
16th to endDay
14%222%31%20%7%
364
August1st to 15thDay
15%114%33%23%10%
313
16th to endDay
19%314%30%22%10%
332
September1st to 15thDay
15%320%26%20%13%
315
16th to endDay
17%420%23%25%9%
314
October1st to 15thDay
21%8%27%25%11%4
315
16th to endDay
35%15%25%19%3
297
November1st to 15thDay
29%8%25%27%7%1
112
16th to endDay
31%11%34%18%4
90
December1st to 15thDay
24%27%26%15%5%
90
16th to endDay
33%25%31%10%
96
January1st to 15thNight
24%18%32%18%4
975
16th to endNight
18%13%34%25%6%
842
February1st to 15thNight
19%15%36%23%4
760
16th to endNight
21%10%32%26%7%
631
March1st to 15thNight
20%13%35%22%7%
720
16th to endNight
18%7%30%28%12%1
768
April1st to 15thNight
24%9%32%25%7%
673
16th to endNight
22%7%27%27%14%1
540
May1st to 15thNight
20%5%20%35%16%2
528
16th to endNight
14%227%35%18%
375
June1st to 15thNight
16%422%39%15%1
360
16th to endNight
13%220%42%19%
360
July1st to 15thNight
10%217%47%20%1
340
16th to endNight
9%221%40%23%2
528
August1st to 15thNight
13%215%36%29%3
539
16th to endNight
14%217%35%26%4
576
September1st to 15thNight
16%420%31%18%8%
720
16th to endNight
15%6%19%30%22%5%
717
October1st to 15thNight
25%6%25%27%11%2
720
16th to endNight
35%12%25%23%3
768
November1st to 15thNight
28%11%30%19%8%1
760
16th to endNight
29%16%28%19%5%
780
December1st to 15thNight
29%20%33%13%2
780
16th to endNight
28%16%35%16%3
995
Page generated at 2018-02-15 10:58:41. Version ac04

Copyright 2018 A. Danko


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