Simcoe
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Simcoe clear sky chart from 2005-11-05 to 2018-08-29.

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
37%
16098
16%
50598
10%
16062
43%
16062
19%
34782

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
17%
776
11%
2609
6%
776
25%
776
9%
2022
January16th to endNight
17%
832
11%
2704
4%
832
26%
832
10%
2107
February1st to 15thNight
18%
761
9%
2482
2%
761
25%
761
9%
1966
February16th to endNight
22%
683
12%
2149
5%
683
31%
683
14%
1616
March1st to 15thNight
28%
780
16%
2152
8%
780
34%
780
17%
1602
March16th to endNight
34%
832
21%
2288
11%
832
42%
832
24%
1564
April1st to 15thNight
29%
778
15%
2001
7%
778
34%
778
20%
1466
April16th to endNight
40%
582
21%
1738
10%
582
48%
582
27%
1110
May1st to 15thNight
43%
585
17%
1755
11%
585
49%
585
24%
1163
May16th to endNight
52%
420
17%
1639
18%
420
59%
420
25%
928
June1st to 15thNight
48%
390
15%
1560
15%
390
58%
390
22%
921
June16th to endNight
56%
390
15%
1503
19%
390
61%
390
25%
882
July1st to 15thNight
64%
373
19%
1483
24%
373
71%
373
33%
736
July16th to endNight
62%
612
16%
1739
14%
579
64%
579
34%
1011
August1st to 15thNight
68%
575
19%
1715
16%
572
71%
572
34%
1026
August16th to endNight
64%
652
23%
1882
16%
652
68%
652
37%
1100
September1st to 15thNight
56%
720
23%
1851
14%
720
60%
720
35%
1176
September16th to endNight
60%
717
25%
1980
19%
717
64%
717
34%
1216
October1st to 15thNight
45%
720
19%
2160
17%
720
50%
720
25%
1403
October16th to endNight
27%
768
17%
2304
10%
768
36%
768
17%
1648
November1st to 15thNight
36%
760
19%
2532
15%
760
44%
760
21%
1657
November16th to endNight
23%
780
13%
2730
7%
780
32%
780
13%
1944
December1st to 15thNight
15%
780
8%
2730
4%
780
21%
780
8%
2147
December16th to endNight
15%
832
8%
2912
2%
832
21%
832
7%
2371

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%36%6%35%45%7%32%
51585
Night
14%8%46%5%3445%7%35%
50781
Cloud CoverDay
15%8%36%6%35%45%7%33%
51595
Night
15%8%46%5%3445%7%35%
50785
TransparencyDay
49%5%11%20%10%1
51286
Night
49%410%21%12%1
50598
SeeingDay
17%6%25%25%16%8%
6514
Night
19%7%26%30%14%1
16106

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%5%8%7%36%447%19%
1656
16th to endDay
14%16%7%11%8%36%45%5%17%
1872
February1st to 15thDay
16%16%6%11%7%45%44418%
1710
16th to endDay
18%10%6%10%7%44436%21%
1608
March1st to 15thDay
17%13%5%9%7%34346%24%
2127
16th to endDay
16%9%5%7%6%24446%32%
2288
April1st to 15thDay
19%10%48%7%3335%6%27%
2286
16th to endDay
17%7%36%423346%38%
2500
May1st to 15thDay
15%6%36%7%35%447%35%
2526
16th to endDay
11%5%345%345%5%8%41%
2824
June1st to 15thDay
12%6%26%5%25%5%6%8%39%
2730
16th to endDay
11%5%25%5%246%7%9%38%
2730
July1st to 15thDay
8%415%5%35%5%6%9%44%
2724
16th to endDay
8%5%25%6%36%6%8%9%36%
2673
August1st to 15thDay
7%5%25%6%36%6%7%9%38%
2487
16th to endDay
10%5%26%4346%5%9%40%
2603
September1st to 15thDay
13%5%246%345%6%8%39%
2106
16th to endDay
13%5%25%5%3446%6%41%
1980
October1st to 15thDay
16%7%36%6%35%45%7%33%
1800
16th to endDay
21%10%47%5%3445%6%25%
1920
November1st to 15thDay
13%7%36%6%3445%8%35%
1651
16th to endDay
21%10%45%5%25%5%6%7%24%
1560
December1st to 15thDay
16%17%5%7%7%35%446%21%
1560
16th to endDay
20%15%7%10%7%35%44415%
1664
January1st to 15thNight
19%14%5%8%6%34345%23%
2609
16th to endNight
13%13%7%8%7%45%45%6%21%
2704
February1st to 15thNight
15%14%6%9%7%45%445%22%
2480
16th to endNight
17%11%5%8%6%35%5%5%7%25%
2149
March1st to 15thNight
17%8%37%5%36%45%6%29%
2140
16th to endNight
15%8%45%424445%39%
2288
April1st to 15thNight
20%7%45%5%2445%7%31%
2001
16th to endNight
12%5%25%5%25%45%7%41%
1738
May1st to 15thNight
15%5%36%5%3446%8%36%
1755
16th to endNight
10%5%25%5%2446%8%45%
1637
June1st to 15thNight
10%5%26%5%35%46%8%41%
1560
16th to endNight
8%5%25%5%35%46%9%43%
1503
July1st to 15thNight
431342435%8%55%
1563
16th to endNight
6%4245%335%7%8%47%
1847
August1st to 15thNight
6%3146%345%7%10%47%
1726
16th to endNight
9%3135%24448%51%
1882
September1st to 15thNight
11%5%35%423446%47%
1851
16th to endNight
11%3245%3345%6%48%
1980
October1st to 15thNight
16%6%25%423347%42%
2160
16th to endNight
19%9%35%5%245%5%6%32%
2304
November1st to 15thNight
14%7%36%5%2445%8%37%
2532
16th to endNight
18%10%46%5%4445%7%28%
2730
December1st to 15thNight
21%14%6%7%5%23446%22%
2730
16th to endNight
21%12%7%9%7%345%45%18%
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
17%14%5%8%5%46%35%6%20%
1656
16th to endDay
14%16%6%11%8%45%445%18%
1872
February1st to 15thDay
16%16%6%11%8%45%33418%
1710
16th to endDay
18%11%6%11%7%34436%22%
1608
March1st to 15thDay
17%12%5%8%7%34345%25%
2138
16th to endDay
17%9%5%7%5%34346%32%
2287
April1st to 15thDay
20%10%47%6%3435%5%28%
2286
16th to endDay
18%8%25%424446%38%
2500
May1st to 15thDay
15%6%36%6%35%35%7%35%
2526
16th to endDay
12%6%245%345%5%8%42%
2824
June1st to 15thDay
12%6%26%425%5%5%8%40%
2730
16th to endDay
12%5%25%5%346%7%9%39%
2730
July1st to 15thDay
8%4245%35%5%6%9%44%
2724
16th to endDay
9%425%6%36%5%8%10%36%
2673
August1st to 15thDay
8%5%245%37%6%7%9%38%
2487
16th to endDay
11%425%5%35%5%5%8%41%
2603
September1st to 15thDay
13%5%245%345%6%9%38%
2106
16th to endDay
13%425%6%35%45%7%41%
1980
October1st to 15thDay
17%6%26%6%35%45%7%34%
1800
16th to endDay
21%10%48%4345%5%5%26%
1920
November1st to 15thDay
13%7%27%7%3445%8%36%
1651
16th to endDay
21%11%36%4245%6%7%25%
1560
December1st to 15thDay
17%15%6%7%6%34445%22%
1560
16th to endDay
21%15%7%8%7%35%5%45%15%
1664
January1st to 15thNight
20%14%5%8%5%34345%23%
2609
16th to endNight
14%13%7%8%7%35%45%6%22%
2704
February1st to 15thNight
15%14%5%9%7%46%445%23%
2473
16th to endNight
17%11%48%6%35%45%6%26%
2149
March1st to 15thNight
18%7%38%446%45%6%29%
2152
16th to endNight
15%8%45%424445%40%
2288
April1st to 15thNight
20%8%35%5%34447%32%
2001
16th to endNight
12%6%26%5%25%45%7%42%
1738
May1st to 15thNight
15%6%25%6%245%5%8%37%
1754
16th to endNight
10%5%2442446%8%45%
1637
June1st to 15thNight
10%5%35%5%35%46%9%40%
1560
16th to endNight
8%435%5%35%46%9%43%
1503
July1st to 15thNight
5%31443435%9%55%
1563
16th to endNight
6%4245%246%6%8%48%
1847
August1st to 15thNight
6%3145%35%5%6%10%47%
1726
16th to endNight
9%314434447%52%
1882
September1st to 15thNight
12%435%42445%7%47%
1851
16th to endNight
11%4245%3345%6%49%
1980
October1st to 15thNight
16%6%35%424347%42%
2160
16th to endNight
20%8%35%42445%6%33%
2304
November1st to 15thNight
15%6%35%5%2445%7%38%
2532
16th to endNight
19%10%35%5%3445%7%29%
2730
December1st to 15thNight
21%15%5%8%5%23447%22%
2730
16th to endNight
21%12%6%8%6%345%46%18%
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%5%9%13%7%
1657
16th to endDay
68%5%9%12%4
1872
February1st to 15thDay
69%38%13%4
1712
16th to endDay
64%5%8%14%5%
1608
March1st to 15thDay
61%5%9%16%6%
2138
16th to endDay
53%48%21%10%1
2288
April1st to 15thDay
57%410%17%10%
2286
16th to endDay
46%39%21%16%2
2500
May1st to 15thDay
47%5%10%23%12%
2526
16th to endDay
39%5%13%25%14%1
2828
June1st to 15thDay
40%7%12%25%12%1
2730
16th to endDay
38%7%14%24%15%
2730
July1st to 15thDay
34%6%9%26%20%2
2575
16th to endDay
39%7%15%22%12%1
2518
August1st to 15thDay
37%7%15%25%12%1
2474
16th to endDay
37%7%13%27%12%1
2603
September1st to 15thDay
40%6%13%25%12%
2106
16th to endDay
40%6%13%26%12%
1980
October1st to 15thDay
49%5%11%20%11%1
1800
16th to endDay
57%5%14%15%6%
1920
November1st to 15thDay
46%5%14%22%9%1
1651
16th to endDay
57%5%14%15%6%
1560
December1st to 15thDay
64%5%12%12%4
1560
16th to endDay
72%5%7%11%3
1664
January1st to 15thNight
64%38%12%9%1
2609
16th to endNight
63%49%15%6%
2704
February1st to 15thNight
63%6%9%14%6%
2482
16th to endNight
58%49%18%7%
2149
March1st to 15thNight
55%5%8%21%8%1
2152
16th to endNight
46%49%22%15%2
2288
April1st to 15thNight
53%38%19%13%
2001
16th to endNight
42%38%22%19%4
1738
May1st to 15thNight
44%5%9%25%12%2
1755
16th to endNight
36%5%12%25%17%2
1639
June1st to 15thNight
40%5%9%27%15%1
1560
16th to endNight
38%5%12%24%17%2
1503
July1st to 15thNight
29%38%27%26%4
1483
16th to endNight
31%5%14%26%18%3
1739
August1st to 15thNight
31%7%13%32%13%1
1715
16th to endNight
32%412%31%17%2
1882
September1st to 15thNight
35%411%28%16%2
1851
16th to endNight
35%311%30%17%1
1980
October1st to 15thNight
43%410%24%16%
2160
16th to endNight
51%5%11%21%9%
2304
November1st to 15thNight
45%5%12%21%13%1
2532
16th to endNight
55%413%18%7%
2730
December1st to 15thNight
64%5%10%13%5%
2730
16th to endNight
67%6%9%11%4
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
21%21%35%14%6%1
114
16th to endDay
28%18%38%11%2
144
February1st to 15thDay
22%14%50%12%
135
16th to endDay
24%21%40%12%
120
March1st to 15thDay
24%8%28%29%9%
323
16th to endDay
24%5%35%23%9%1
352
April1st to 15thDay
24%11%30%22%9%1
330
16th to endDay
19%430%24%13%7%
319
May1st to 15thDay
22%6%24%26%13%7%
348
16th to endDay
13%5%23%31%18%7%
395
June1st to 15thDay
14%426%34%17%2
375
16th to endDay
16%225%30%19%6%
375
July1st to 15thDay
10%217%26%26%15%
365
16th to endDay
10%120%31%25%11%
390
August1st to 15thDay
9%16%32%23%18%
358
16th to endDay
12%116%26%21%20%
384
September1st to 15thDay
9%118%23%29%17%
315
16th to endDay
15%315%21%23%19%
314
October1st to 15thDay
22%422%23%20%6%
315
16th to endDay
23%10%30%23%10%1
336
November1st to 15thDay
17%8%34%23%12%3
131
16th to endDay
26%14%32%18%6%1
90
December1st to 15thDay
24%23%28%16%6%
90
16th to endDay
27%23%35%10%3
96
January1st to 15thNight
27%13%31%20%5%
780
16th to endNight
22%14%33%24%5%
832
February1st to 15thNight
24%14%33%25%2
764
16th to endNight
23%9%34%26%5%
683
March1st to 15thNight
22%7%32%27%8%
780
16th to endNight
19%6%32%29%11%1
832
April1st to 15thNight
24%9%29%28%6%
778
16th to endNight
15%331%35%12%1
582
May1st to 15thNight
17%224%34%18%2
585
16th to endNight
12%124%36%21%2
421
June1st to 15thNight
13%126%40%18%
390
16th to endNight
10%121%47%18%1
390
July1st to 15thNight
5%122%40%28%1
373
16th to endNight
9%16%47%23%3
612
August1st to 15thNight
7%113%42%30%4
575
16th to endNight
11%13%35%32%4
652
September1st to 15thNight
13%316%33%28%5%
720
16th to endNight
13%214%29%30%8%
717
October1st to 15thNight
20%5%20%30%19%3
720
16th to endNight
25%8%30%27%7%
768
November1st to 15thNight
19%8%27%29%12%2
760
16th to endNight
26%12%30%20%9%
780
December1st to 15thNight
30%13%31%19%5%
780
16th to endNight
28%11%33%23%3
832
Page generated at 2018-08-30 05:34:20. Version ac04

Copyright 2018 A. Danko


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