Barrie
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Barrie clear sky chart from 2005-11-05 to 2018-02-22.

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
35%
15402
12%
48652
9%
15368
40%
15368
17%
35061

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
16%
777
7%
2693
3%
776
21%
776
7%
2213
January16th to endNight
23%
832
8%
2704
4%
832
27%
832
7%
2253
February1st to 15thNight
19%
761
7%
2482
3%
761
25%
761
9%
1988
February16th to endNight
25%
659
11%
2114
5%
659
32%
659
13%
1593
March1st to 15thNight
25%
720
12%
1980
7%
720
30%
720
16%
1493
March16th to endNight
37%
768
20%
2112
11%
768
43%
768
25%
1433
April1st to 15thNight
29%
718
14%
1821
6%
718
33%
718
22%
1342
April16th to endNight
42%
546
19%
1626
11%
546
47%
546
24%
1101
May1st to 15thNight
48%
483
15%
1563
12%
483
52%
483
23%
1010
May16th to endNight
50%
374
16%
1497
15%
374
59%
374
25%
829
June1st to 15thNight
48%
360
11%
1419
12%
360
55%
360
21%
858
June16th to endNight
55%
360
12%
1260
15%
360
58%
360
25%
768
July1st to 15thNight
62%
340
17%
1248
22%
340
67%
340
33%
660
July16th to endNight
60%
476
16%
1510
17%
446
62%
446
28%
895
August1st to 15thNight
66%
539
16%
1609
12%
536
69%
536
35%
940
August16th to endNight
61%
612
20%
1758
13%
612
64%
612
33%
1082
September1st to 15thNight
54%
720
18%
1815
10%
720
57%
720
32%
1200
September16th to endNight
54%
717
21%
2000
16%
717
57%
717
30%
1286
October1st to 15thNight
37%
720
14%
2160
13%
720
41%
720
20%
1525
October16th to endNight
24%
768
11%
2304
7%
768
30%
768
12%
1799
November1st to 15thNight
32%
760
14%
2605
12%
760
37%
760
15%
1865
November16th to endNight
24%
780
9%
2730
7%
780
28%
780
10%
2143
December1st to 15thNight
15%
780
4%
2730
1%
780
17%
780
6%
2288
December16th to endNight
13%
832
5%
2912
1%
832
18%
832
5%
2497

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
15%8%37%6%35%5%5%7%32%
49598
Night
15%9%47%6%35%45%6%31%
48826
Cloud CoverDay
14%8%37%6%35%5%5%7%32%
49608
Night
15%9%47%6%35%45%6%31%
48830
TransparencyDay
50%7%12%18%9%
49290
Night
52%6%12%18%9%
48652
SeeingDay
18%5%25%26%16%6%
6070
Night
19%7%28%29%12%1
15409

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%14%49%9%35%446%19%
1572
16th to endDay
13%16%7%12%8%35%6%45%16%
1872
February1st to 15thDay
12%13%6%12%9%47%445%18%
1710
16th to endDay
14%13%6%11%7%45%445%20%
1503
March1st to 15thDay
14%10%48%7%46%445%28%
1969
16th to endDay
14%9%46%5%24345%38%
2112
April1st to 15thDay
21%9%35%5%245%45%31%
2132
16th to endDay
18%7%35%423346%39%
2340
May1st to 15thDay
17%7%25%6%2445%6%36%
2388
16th to endDay
12%5%245%245%5%7%43%
2618
June1st to 15thDay
18%5%344245%6%8%36%
2538
16th to endDay
14%425%435%46%10%37%
2700
July1st to 15thDay
9%425%6%35%5%5%9%42%
2634
16th to endDay
10%425%5%35%6%7%9%38%
2553
August1st to 15thDay
10%5%26%5%245%6%8%41%
2340
16th to endDay
10%416%5%35%46%9%40%
2432
September1st to 15thDay
16%6%25%5%35%5%46%37%
2142
16th to endDay
15%4245%35%45%6%41%
1959
October1st to 15thDay
22%7%38%5%33446%31%
1800
16th to endDay
26%11%38%6%3445%5%20%
1920
November1st to 15thDay
18%11%38%5%345%5%6%26%
1580
16th to endDay
20%15%5%8%7%46%45%5%15%
1560
December1st to 15thDay
16%17%9%11%8%35%5%45%13%
1560
16th to endDay
20%14%7%10%7%346%46%14%
1664
January1st to 15thNight
17%13%6%10%8%46%45%5%16%
2693
16th to endNight
14%13%7%12%8%47%5%5%5%15%
2704
February1st to 15thNight
11%15%6%12%9%46%45%417%
2480
16th to endNight
16%11%6%11%6%25%5%5%5%23%
2114
March1st to 15thNight
16%10%48%8%35%33430%
1968
16th to endNight
14%7%46%424445%40%
2112
April1st to 15thNight
20%8%36%5%33346%33%
1821
16th to endNight
14%8%35%6%34436%39%
1626
May1st to 15thNight
17%5%25%5%3446%6%38%
1563
16th to endNight
11%5%3442445%7%46%
1495
June1st to 15thNight
14%425%5%445%5%7%40%
1419
16th to endNight
10%5%25%5%35%6%5%7%43%
1260
July1st to 15thNight
6%424424347%54%
1323
16th to endNight
7%424445%47%8%47%
1614
August1st to 15thNight
7%314425%6%7%9%48%
1620
16th to endNight
9%425%5%25%446%49%
1758
September1st to 15thNight
14%425%42445%7%44%
1815
16th to endNight
13%6%25%41345%6%45%
2000
October1st to 15thNight
19%6%36%6%34445%35%
2160
16th to endNight
23%9%36%7%45%5%5%5%23%
2304
November1st to 15thNight
18%9%37%435%46%6%30%
2605
16th to endNight
19%13%47%6%45%46%5%21%
2730
December1st to 15thNight
18%16%6%10%8%45%45%5%15%
2730
16th to endNight
20%16%7%11%7%44445%13%
2912

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%13%5%8%8%46%45%7%19%
1572
16th to endDay
12%16%6%12%8%45%5%46%16%
1872
February1st to 15thDay
12%13%6%12%9%36%5%5%419%
1710
16th to endDay
15%13%6%10%8%45%445%21%
1503
March1st to 15thDay
14%9%48%7%45%5%5%5%29%
1980
16th to endDay
14%8%47%5%34445%38%
2111
April1st to 15thDay
20%8%36%6%245%5%5%31%
2132
16th to endDay
17%7%26%5%23347%39%
2340
May1st to 15thDay
16%6%25%7%2445%6%37%
2388
16th to endDay
12%5%244335%6%8%42%
2618
June1st to 15thDay
16%5%35%5%2445%8%37%
2538
16th to endDay
13%5%25%5%35%46%10%37%
2700
July1st to 15thDay
8%5%25%6%36%45%9%42%
2634
16th to endDay
9%5%25%6%35%5%8%9%38%
2553
August1st to 15thDay
9%426%6%246%6%9%40%
2340
16th to endDay
9%5%25%5%35%5%6%9%41%
2432
September1st to 15thDay
15%7%35%4345%5%7%37%
2142
16th to endDay
14%5%25%6%3445%6%41%
1959
October1st to 15thDay
20%8%37%7%24446%31%
1800
16th to endDay
24%12%38%6%3445%5%20%
1920
November1st to 15thDay
16%12%38%6%35%45%6%26%
1580
16th to endDay
18%14%5%9%6%46%6%47%15%
1560
December1st to 15thDay
16%13%10%11%9%35%45%5%13%
1560
16th to endDay
19%14%7%9%8%35%5%5%7%13%
1664
January1st to 15thNight
16%13%6%9%8%46%5%5%5%17%
2693
16th to endNight
13%13%7%11%9%46%5%5%6%15%
2704
February1st to 15thNight
11%13%6%12%10%45%5%5%5%18%
2473
16th to endNight
15%10%5%11%7%35%45%6%24%
2114
March1st to 15thNight
16%9%5%8%8%35%33431%
1980
16th to endNight
14%7%45%324346%40%
2112
April1st to 15thNight
20%7%46%5%24446%33%
1821
16th to endNight
14%7%46%5%24446%39%
1626
May1st to 15thNight
15%5%25%6%3445%8%38%
1562
16th to endNight
11%5%2443445%8%47%
1495
June1st to 15thNight
13%425%5%35%5%6%8%40%
1419
16th to endNight
9%6%245%45%6%5%7%43%
1260
July1st to 15thNight
6%435%414446%55%
1323
16th to endNight
7%334435%46%8%47%
1614
August1st to 15thNight
6%313435%5%7%9%48%
1620
16th to endNight
9%4245%245%5%6%49%
1758
September1st to 15thNight
13%5%25%42446%6%44%
1815
16th to endNight
12%6%35%32335%6%46%
2000
October1st to 15thNight
19%7%25%6%34445%35%
2160
16th to endNight
21%10%37%6%45%46%6%24%
2304
November1st to 15thNight
18%9%36%5%35%45%7%30%
2605
16th to endNight
19%12%5%8%6%35%5%5%5%22%
2730
December1st to 15thNight
17%15%6%10%7%45%45%5%16%
2730
16th to endNight
20%14%7%12%8%44446%13%
2912

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
64%8%10%11%4
1573
16th to endDay
67%7%10%9%5%
1872
February1st to 15thDay
66%7%8%12%3
1712
16th to endDay
62%6%10%12%6%
1503
March1st to 15thDay
55%7%13%16%6%
1980
16th to endDay
47%5%10%17%17%1
2112
April1st to 15thDay
53%5%9%19%11%
2132
16th to endDay
45%5%10%22%14%2
2340
May1st to 15thDay
46%5%10%21%14%1
2388
16th to endDay
38%8%13%23%13%2
2622
June1st to 15thDay
43%7%12%24%13%
2538
16th to endDay
41%8%14%21%13%
2700
July1st to 15thDay
36%8%12%24%15%1
2480
16th to endDay
40%9%13%24%11%1
2394
August1st to 15thDay
38%8%16%21%13%1
2327
16th to endDay
37%8%16%25%9%1
2432
September1st to 15thDay
45%7%13%23%10%
2142
16th to endDay
43%7%11%28%8%
1959
October1st to 15thDay
54%5%10%19%9%
1800
16th to endDay
64%7%13%10%4
1920
November1st to 15thDay
56%8%13%15%6%
1580
16th to endDay
66%8%12%9%2
1560
December1st to 15thDay
71%9%10%7%1
1560
16th to endDay
70%7%10%8%2
1664
January1st to 15thNight
66%8%10%9%3
2693
16th to endNight
68%7%9%10%3
2704
February1st to 15thNight
65%6%10%14%3
2482
16th to endNight
59%5%13%15%6%
2114
March1st to 15thNight
57%412%18%6%
1980
16th to endNight
44%411%21%16%1
2112
April1st to 15thNight
51%5%10%17%14%
1821
16th to endNight
45%5%10%18%18%2
1626
May1st to 15thNight
43%5%12%18%16%2
1563
16th to endNight
34%6%14%27%14%2
1497
June1st to 15thNight
40%6%12%24%14%
1419
16th to endNight
37%7%14%24%15%
1260
July1st to 15thNight
29%5%10%31%21%1
1248
16th to endNight
34%7%11%30%14%1
1510
August1st to 15thNight
28%9%20%26%14%
1609
16th to endNight
32%8%14%26%16%1
1758
September1st to 15thNight
37%7%15%26%12%1
1815
16th to endNight
38%6%13%29%12%
2000
October1st to 15thNight
48%7%11%20%11%
2160
16th to endNight
58%8%12%14%5%
2304
November1st to 15thNight
52%7%14%17%7%1
2605
16th to endNight
61%7%14%12%2
2730
December1st to 15thNight
69%8%12%7%2
2730
16th to endNight
73%6%9%7%2
2912

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
17%12%43%18%6%1
95
16th to endDay
30%8%35%25%
144
February1st to 15thDay
21%12%45%20%
135
16th to endDay
26%17%33%23%1
100
March1st to 15thDay
18%11%34%26%8%
270
16th to endDay
24%331%24%12%3
288
April1st to 15thDay
24%7%31%21%11%3
270
16th to endDay
21%5%24%25%16%5%
270
May1st to 15thDay
20%322%27%18%7%
288
16th to endDay
15%225%31%18%6%
331
June1st to 15thDay
21%418%32%20%3
333
16th to endDay
15%225%34%17%3
495
July1st to 15thDay
11%222%32%23%8%
414
16th to endDay
9%120%34%22%11%
326
August1st to 15thDay
10%17%28%26%15%
313
16th to endDay
12%117%25%25%17%
332
September1st to 15thDay
16%215%21%26%16%
315
16th to endDay
13%316%27%24%14%
314
October1st to 15thDay
20%6%27%24%14%7%
315
16th to endDay
27%10%33%21%6%
336
November1st to 15thDay
21%14%26%23%11%1
110
16th to endDay
28%15%40%12%3
90
December1st to 15thDay
15%22%34%21%5%1
90
16th to endDay
25%14%46%12%1
96
January1st to 15thNight
22%11%38%20%6%
780
16th to endNight
20%7%35%28%7%
832
February1st to 15thNight
19%9%39%26%5%
764
16th to endNight
22%8%34%28%6%
659
March1st to 15thNight
20%10%35%28%6%
720
16th to endNight
18%7%29%29%13%
768
April1st to 15thNight
23%7%31%29%6%
718
16th to endNight
19%5%26%34%13%1
546
May1st to 15thNight
19%222%37%17%1
483
16th to endNight
11%326%40%17%
375
June1st to 15thNight
14%422%42%15%
360
16th to endNight
12%121%43%20%
360
July1st to 15thNight
6%219%46%22%2
340
16th to endNight
10%121%40%25%1
476
August1st to 15thNight
8%15%42%30%2
539
16th to endNight
11%117%35%30%3
612
September1st to 15thNight
15%319%31%21%7%
720
16th to endNight
15%5%17%30%24%6%
717
October1st to 15thNight
21%5%28%28%14%1
720
16th to endNight
26%10%32%23%7%
768
November1st to 15thNight
22%8%29%25%12%1
760
16th to endNight
25%12%30%24%7%
780
December1st to 15thNight
27%12%37%17%3
780
16th to endNight
27%12%34%21%3
832
Page generated at 2018-02-23 11:21:32. Version ac04

Copyright 2018 A. Danko


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