Point Pelee National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Point Pelee National Park clear sky chart from 2005-11-05 to 2017-08-12.

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
41%
15289
14%
46427
11%
15250
45%
15250
19%
33085

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
19%
858
10%
2467
4%
856
24%
856
12%
1999
January16th to endNight
20%
768
8%
2496
3%
768
26%
768
9%
2015
February1st to 15thNight
23%
701
9%
2284
3%
701
30%
701
12%
1775
February16th to endNight
27%
631
12%
1893
7%
631
33%
631
14%
1442
March1st to 15thNight
35%
720
15%
2046
9%
720
39%
720
18%
1510
March16th to endNight
42%
768
18%
2112
12%
768
47%
768
24%
1496
April1st to 15thNight
39%
638
14%
1836
8%
638
44%
638
21%
1316
April16th to endNight
48%
540
20%
1620
12%
540
54%
540
26%
1051
May1st to 15thNight
47%
540
13%
1620
9%
540
51%
540
20%
1154
May16th to endNight
59%
562
15%
1684
13%
561
62%
561
29%
1066
June1st to 15thNight
60%
384
16%
1385
19%
384
62%
384
24%
846
June16th to endNight
64%
410
18%
1310
19%
410
68%
410
28%
794
July1st to 15thNight
68%
510
16%
1360
15%
510
69%
510
37%
828
July16th to endNight
72%
564
17%
1590
16%
531
73%
531
37%
906
August1st to 15thNight
70%
527
20%
1575
17%
524
71%
524
33%
938
August16th to endNight
69%
525
21%
1575
17%
525
72%
525
33%
944
September1st to 15thNight
64%
642
23%
1778
17%
642
67%
642
31%
1131
September16th to endNight
58%
657
21%
1815
16%
657
62%
657
28%
1187
October1st to 15thNight
47%
660
18%
1919
17%
660
49%
660
24%
1312
October16th to endNight
27%
704
14%
2159
8%
704
34%
704
15%
1579
November1st to 15thNight
38%
700
18%
2276
17%
700
42%
700
20%
1541
November16th to endNight
24%
720
11%
2436
9%
720
27%
720
11%
1888
December1st to 15thNight
16%
720
6%
2520
3%
720
20%
720
7%
2111
December16th to endNight
16%
840
6%
2671
2%
840
20%
840
7%
2256

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%7%36%5%345%5%7%35%
47511
Night
16%8%46%5%3445%6%33%
46609
Cloud CoverDay
13%7%36%5%35%5%5%7%35%
47521
Night
16%8%36%5%3445%6%33%
46613
TransparencyDay
45%7%13%20%11%1
47211
Night
50%6%11%18%11%1
46427
SeeingDay
16%317%31%24%6%
5551
Night
20%5%24%29%16%3
15296

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
20%14%5%8%8%35%445%18%
1467
16th to endDay
16%16%6%10%8%3445%6%16%
1728
February1st to 15thDay
15%12%6%9%8%45%35%6%22%
1575
16th to endDay
14%10%5%9%8%45%5%5%6%25%
1580
March1st to 15thDay
18%9%5%7%6%3445%6%27%
1903
16th to endDay
18%7%47%6%24437%31%
2112
April1st to 15thDay
16%6%45%5%36%46%7%33%
2122
16th to endDay
15%5%35%43445%7%40%
2340
May1st to 15thDay
16%6%25%5%35%6%5%8%34%
2331
16th to endDay
10%5%244245%6%8%43%
2431
June1st to 15thDay
10%5%244345%6%8%43%
2566
16th to endDay
7%4245%25%7%6%11%40%
2645
July1st to 15thDay
7%4233345%5%10%48%
2520
16th to endDay
7%4145%25%46%9%47%
2468
August1st to 15thDay
6%415%5%25%5%7%9%45%
2288
16th to endDay
9%3145%2446%10%47%
2275
September1st to 15thDay
12%6%3442335%8%45%
1838
16th to endDay
15%5%33335%47%7%41%
1815
October1st to 15thDay
15%7%36%5%24446%38%
1710
16th to endDay
22%8%2443445%6%32%
1711
November1st to 15thDay
15%7%35%5%3445%7%38%
1582
16th to endDay
18%14%5%7%5%3446%5%24%
1521
December1st to 15thDay
20%14%8%10%6%45%5%5%415%
1440
16th to endDay
21%13%7%9%8%345%45%16%
1543
January1st to 15thNight
22%13%5%7%7%34435%21%
2467
16th to endNight
16%15%8%9%6%35%445%20%
2496
February1st to 15thNight
16%13%5%8%6%3445%5%24%
2282
16th to endNight
17%11%6%8%6%34445%26%
1893
March1st to 15thNight
18%9%36%6%3445%6%30%
2034
16th to endNight
15%8%36%5%3445%7%36%
2112
April1st to 15thNight
17%8%36%4345%5%6%34%
1836
16th to endNight
13%5%25%5%35%5%5%7%40%
1620
May1st to 15thNight
17%6%35%7%35%5%5%8%31%
1620
16th to endNight
11%425%5%3445%7%44%
1682
June1st to 15thNight
11%325%6%345%5%7%43%
1385
16th to endNight
9%3236%26%5%6%9%44%
1310
July1st to 15thNight
7%3244245%5%8%50%
1440
16th to endNight
5%315%42446%9%52%
1697
August1st to 15thNight
5%424435%6%6%9%46%
1586
16th to endNight
10%3243245%5%7%49%
1575
September1st to 15thNight
10%5%145%3445%5%49%
1778
16th to endNight
12%5%25%43445%7%43%
1815
October1st to 15thNight
18%5%26%434347%39%
1919
16th to endNight
22%7%36%5%43445%31%
2159
November1st to 15thNight
15%8%36%5%2345%6%37%
2276
16th to endNight
25%12%5%7%5%23346%23%
2436
December1st to 15thNight
23%15%6%10%7%3434416%
2520
16th to endNight
24%14%6%9%8%33445%14%
2671

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
19%14%48%8%46%346%17%
1467
16th to endDay
16%15%6%10%8%35%45%5%17%
1728
February1st to 15thDay
15%12%6%9%8%35%45%6%22%
1575
16th to endDay
14%10%5%9%8%35%5%5%6%25%
1580
March1st to 15thDay
18%10%5%7%6%345%5%6%26%
1914
16th to endDay
17%8%48%6%24447%31%
2111
April1st to 15thDay
16%6%46%6%26%5%5%6%32%
2122
16th to endDay
15%5%35%5%34446%39%
2340
May1st to 15thDay
15%7%26%5%35%5%5%8%34%
2331
16th to endDay
10%5%25%5%245%6%8%43%
2431
June1st to 15thDay
9%5%25%5%35%5%6%8%43%
2566
16th to endDay
7%425%5%25%6%7%11%40%
2645
July1st to 15thDay
7%423425%5%7%8%48%
2520
16th to endDay
7%415%5%25%46%10%47%
2468
August1st to 15thDay
6%415%5%35%5%8%10%44%
2288
16th to endDay
8%3244345%6%10%47%
2275
September1st to 15thDay
12%6%24423448%45%
1838
16th to endDay
15%5%34325%5%6%7%41%
1815
October1st to 15thDay
15%7%36%6%2445%6%38%
1710
16th to endDay
22%8%35%43445%6%31%
1711
November1st to 15thDay
14%7%345%3445%7%37%
1582
16th to endDay
18%14%5%7%5%3445%6%24%
1521
December1st to 15thDay
20%14%8%10%6%35%45%415%
1440
16th to endDay
21%13%6%10%8%35%445%15%
1543
January1st to 15thNight
22%13%5%7%7%34435%21%
2467
16th to endNight
16%15%7%10%6%44445%20%
2496
February1st to 15thNight
16%12%6%8%7%345%46%24%
2275
16th to endNight
18%10%5%8%7%34446%26%
1893
March1st to 15thNight
18%10%36%6%35%45%6%30%
2046
16th to endNight
15%7%36%5%3445%7%36%
2112
April1st to 15thNight
18%7%45%5%25%45%6%34%
1836
16th to endNight
13%5%25%5%345%6%7%39%
1620
May1st to 15thNight
16%6%25%6%36%5%5%8%31%
1619
16th to endNight
11%425%5%3445%8%44%
1682
June1st to 15thNight
11%416%5%35%5%5%7%43%
1385
16th to endNight
8%3246%35%46%9%44%
1310
July1st to 15thNight
7%324435%45%8%49%
1440
16th to endNight
5%325%4245%6%8%52%
1697
August1st to 15thNight
5%4245%26%6%5%9%47%
1586
16th to endNight
9%325%3335%5%8%49%
1575
September1st to 15thNight
10%5%145%24445%49%
1778
16th to endNight
13%5%25%5%2445%7%43%
1815
October1st to 15thNight
17%6%26%424446%40%
1919
16th to endNight
22%7%26%6%44446%31%
2159
November1st to 15thNight
15%8%36%6%2345%6%37%
2276
16th to endNight
24%12%47%5%2335%6%23%
2436
December1st to 15thNight
22%15%5%11%6%4434416%
2520
16th to endNight
23%13%6%10%7%34446%14%
2671

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
67%6%11%11%3
1468
16th to endDay
66%8%11%8%4
1728
February1st to 15thDay
61%7%9%16%5%
1577
16th to endDay
57%6%13%17%4
1580
March1st to 15thDay
56%8%10%17%6%
1914
16th to endDay
51%6%11%21%8%1
2112
April1st to 15thDay
48%7%12%17%12%
2122
16th to endDay
43%6%11%21%13%3
2340
May1st to 15thDay
44%9%10%20%11%2
2331
16th to endDay
35%8%13%26%13%1
2435
June1st to 15thDay
36%7%14%27%13%1
2566
16th to endDay
33%10%15%21%16%2
2645
July1st to 15thDay
30%7%12%26%20%2
2371
16th to endDay
31%7%15%25%16%2
2312
August1st to 15thDay
31%7%15%30%14%
2275
16th to endDay
30%8%16%26%15%3
2275
September1st to 15thDay
36%5%17%23%15%1
1838
16th to endDay
39%7%11%25%14%
1815
October1st to 15thDay
45%6%11%22%12%1
1710
16th to endDay
51%7%15%16%7%
1711
November1st to 15thDay
45%7%12%19%14%1
1582
16th to endDay
59%6%15%14%4
1521
December1st to 15thDay
70%7%9%9%3
1440
16th to endDay
70%7%9%9%2
1543
January1st to 15thNight
65%5%9%13%5%
2467
16th to endNight
65%6%11%11%3
2496
February1st to 15thNight
61%6%10%15%5%
2284
16th to endNight
58%5%9%18%5%
1893
March1st to 15thNight
53%6%10%19%8%1
2046
16th to endNight
47%6%10%23%10%2
2112
April1st to 15thNight
49%5%10%19%13%
1836
16th to endNight
42%5%11%19%16%5%
1620
May1st to 15thNight
49%7%10%17%11%2
1620
16th to endNight
37%7%11%24%16%2
1684
June1st to 15thNight
37%8%10%26%16%1
1385
16th to endNight
35%7%12%22%19%1
1310
July1st to 15thNight
32%6%11%24%22%2
1360
16th to endNight
26%8%15%24%20%3
1590
August1st to 15thNight
30%8%13%29%15%2
1575
16th to endNight
32%7%12%24%19%2
1575
September1st to 15thNight
35%7%12%23%17%3
1778
16th to endNight
39%6%9%25%17%1
1815
October1st to 15thNight
45%6%11%16%19%1
1919
16th to endNight
54%6%12%18%6%
2159
November1st to 15thNight
46%6%11%19%13%1
2276
16th to endNight
62%5%10%16%4
2436
December1st to 15thNight
72%49%9%3
2520
16th to endNight
72%410%9%2
2671

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
25%7%33%21%12%
90
16th to endDay
32%431%27%5%
96
February1st to 15thDay
21%437%30%6%
90
16th to endDay
17%230%38%11%
81
March1st to 15thDay
27%6%23%31%10%
204
16th to endDay
22%226%35%10%2
288
April1st to 15thDay
19%423%38%12%1
270
16th to endDay
16%226%31%18%4
270
May1st to 15thDay
19%222%32%20%2
288
16th to endDay
14%114%31%31%6%
331
June1st to 15thDay
10%113%38%29%5%
391
16th to endDay
12%215%36%26%6%
495
July1st to 15thDay
9%111%35%33%9%
475
16th to endDay
10%16%29%39%11%
328
August1st to 15thDay
8%17%34%33%14%
297
16th to endDay
11%18%23%40%14%
268
September1st to 15thDay
14%39%22%33%16%
255
16th to endDay
22%111%18%35%11%
254
October1st to 15thDay
16%321%21%27%10%
255
16th to endDay
23%8%26%30%9%1
223
November1st to 15thDay
13%5%15%26%33%5%
90
16th to endDay
21%16%21%32%6%
73
December1st to 15thDay
25%15%25%26%8%
60
16th to endDay
35%7%32%22%1
79
January1st to 15thNight
29%7%34%21%5%
861
16th to endNight
23%9%33%26%7%
768
February1st to 15thNight
23%5%35%28%6%
704
16th to endNight
22%6%30%34%6%
631
March1st to 15thNight
23%5%26%33%10%
720
16th to endNight
18%428%31%14%3
768
April1st to 15thNight
21%5%25%35%9%1
638
16th to endNight
15%224%38%15%3
540
May1st to 15thNight
20%220%33%20%3
540
16th to endNight
13%116%31%27%8%
563
June1st to 15thNight
12%17%39%27%2
384
16th to endNight
9%113%38%32%4
410
July1st to 15thNight
10%110%38%32%7%
510
16th to endNight
6%210%38%34%7%
564
August1st to 15thNight
7%112%39%29%10%
527
16th to endNight
11%211%28%36%9%
525
September1st to 15thNight
13%410%28%32%10%
642
16th to endNight
17%213%28%29%9%
657
October1st to 15thNight
20%420%24%23%6%
660
16th to endNight
25%9%32%24%7%
704
November1st to 15thNight
18%8%28%28%13%3
700
16th to endNight
32%12%26%17%9%
720
December1st to 15thNight
31%11%31%18%5%
720
16th to endNight
28%8%36%21%4
840
Page generated at 2017-08-13 14:16:48. Version ac04

Copyright 2017 A. Danko


Point Pelee National Park Clear Sky Chart | Charts Home