Port Burwell Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Port Burwell Provincial Park clear sky chart from 2005-11-05 to 2017-09-20.

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%
14976
14%
46738
10%
14939
42%
14939
18%
33013

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
14%
717
9%
2374
4%
716
20%
716
7%
1928
January16th to endNight
15%
768
9%
2496
3%
768
21%
768
8%
2029
February1st to 15thNight
16%
701
8%
2287
2%
701
24%
701
9%
1829
February16th to endNight
24%
631
11%
1964
5%
631
32%
631
13%
1503
March1st to 15thNight
26%
720
15%
2000
8%
720
32%
720
17%
1511
March16th to endNight
35%
768
20%
2112
11%
768
41%
768
23%
1478
April1st to 15thNight
30%
700
15%
1844
7%
700
35%
700
22%
1319
April16th to endNight
43%
540
21%
1620
10%
540
51%
540
26%
1035
May1st to 15thNight
44%
540
16%
1620
11%
540
49%
540
23%
1108
May16th to endNight
52%
422
17%
1545
17%
422
57%
422
26%
897
June1st to 15thNight
51%
360
14%
1440
16%
360
58%
360
24%
828
June16th to endNight
56%
360
17%
1293
16%
360
63%
360
27%
761
July1st to 15thNight
66%
380
18%
1327
21%
380
70%
380
34%
703
July16th to endNight
64%
564
15%
1595
14%
531
66%
531
35%
934
August1st to 15thNight
69%
539
18%
1609
14%
536
71%
536
34%
954
August16th to endNight
65%
597
24%
1743
17%
597
68%
597
36%
1024
September1st to 15thNight
60%
720
21%
1875
14%
720
62%
720
32%
1206
September16th to endNight
57%
677
21%
1870
15%
677
61%
677
29%
1203
October1st to 15thNight
47%
660
20%
1966
18%
660
50%
660
24%
1302
October16th to endNight
26%
704
12%
2112
7%
704
33%
704
14%
1575
November1st to 15thNight
39%
700
18%
2318
15%
700
44%
700
19%
1545
November16th to endNight
24%
720
9%
2520
7%
720
27%
720
10%
1955
December1st to 15thNight
14%
720
5%
2520
3%
720
17%
720
7%
2091
December16th to endNight
15%
768
6%
2688
2%
768
19%
768
6%
2295

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%33%
48080
Night
16%8%36%5%3445%7%33%
46922
Cloud CoverDay
14%8%36%5%35%45%7%33%
48090
Night
15%8%36%5%3445%7%33%
46926
TransparencyDay
48%7%13%19%10%1
47783
Night
50%6%11%20%10%1
46738
SeeingDay
17%6%24%27%17%7%
5537
Night
20%7%26%29%14%1
14983

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%13%5%11%7%45%445%17%
1561
16th to endDay
16%14%7%12%8%46%445%15%
1728
February1st to 15thDay
17%14%6%10%6%5%5%44420%
1575
16th to endDay
16%11%7%10%7%35%45%6%20%
1509
March1st to 15thDay
17%11%5%9%6%3445%6%24%
1948
16th to endDay
17%8%5%6%6%44447%30%
2112
April1st to 15thDay
18%7%5%7%5%2446%7%29%
2113
16th to endDay
17%8%25%423447%38%
2340
May1st to 15thDay
16%6%35%5%35%5%5%8%35%
2331
16th to endDay
11%4245%345%5%9%42%
2570
June1st to 15thDay
10%5%25%5%345%6%8%41%
2520
16th to endDay
9%425%5%25%6%7%10%40%
2660
July1st to 15thDay
8%324435%5%7%9%46%
2543
16th to endDay
8%315%435%6%7%12%41%
2465
August1st to 15thDay
7%3145%35%7%8%10%40%
2340
16th to endDay
10%5%245%335%5%10%44%
2447
September1st to 15thDay
11%425%5%46%5%5%8%40%
2082
16th to endDay
14%5%25%4245%6%7%40%
1859
October1st to 15thDay
15%7%36%6%35%5%46%36%
1664
16th to endDay
25%10%36%5%34446%24%
1760
November1st to 15thDay
14%5%25%5%36%5%5%7%37%
1537
16th to endDay
22%12%48%6%345%5%5%21%
1440
December1st to 15thDay
20%16%5%9%8%34445%16%
1440
16th to endDay
22%14%7%11%7%35%44413%
1536
January1st to 15thNight
23%14%5%10%6%3443320%
2374
16th to endNight
16%16%7%10%6%3445%6%18%
2496
February1st to 15thNight
16%14%5%9%7%45%445%21%
2285
16th to endNight
18%11%5%7%7%3446%7%24%
1964
March1st to 15thNight
19%8%46%6%345%46%28%
1988
16th to endNight
16%9%35%4345%46%37%
2112
April1st to 15thNight
20%7%36%424447%34%
1844
16th to endNight
11%5%25%5%35%5%5%6%41%
1620
May1st to 15thNight
15%5%35%5%35%6%6%7%34%
1620
16th to endNight
11%5%34425%46%8%44%
1543
June1st to 15thNight
10%5%25%5%3445%9%42%
1440
16th to endNight
9%5%344445%6%9%43%
1293
July1st to 15thNight
5%323434448%53%
1408
16th to endNight
7%3244245%5%10%47%
1703
August1st to 15thNight
6%3135%35%5%7%10%46%
1620
16th to endNight
8%324324447%52%
1743
September1st to 15thNight
10%5%25%32446%7%46%
1875
16th to endNight
12%4244345%5%7%44%
1870
October1st to 15thNight
16%6%25%324447%41%
1966
16th to endNight
22%8%36%6%2345%7%29%
2112
November1st to 15thNight
15%5%26%5%25%47%7%37%
2318
16th to endNight
22%11%47%6%345%47%22%
2520
December1st to 15thNight
24%13%6%8%5%24447%17%
2520
16th to endNight
22%14%6%9%7%34446%15%
2688

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
20%13%5%11%7%44336%17%
1561
16th to endDay
16%15%7%11%8%5%5%445%14%
1728
February1st to 15thDay
17%15%7%10%6%45%44420%
1575
16th to endDay
17%10%6%11%7%35%45%6%20%
1509
March1st to 15thDay
17%12%49%6%3445%6%24%
1959
16th to endDay
17%9%5%6%6%34346%31%
2111
April1st to 15thDay
18%8%48%5%25%46%7%29%
2113
16th to endDay
17%8%3442345%6%38%
2340
May1st to 15thDay
16%6%35%5%35%5%6%7%35%
2331
16th to endDay
11%5%245%35%46%8%41%
2570
June1st to 15thDay
11%5%25%5%245%6%9%40%
2520
16th to endDay
10%425%425%6%7%9%40%
2660
July1st to 15thDay
8%3144345%7%9%45%
2543
16th to endDay
8%3245%36%5%7%11%40%
2465
August1st to 15thDay
7%4145%45%7%8%10%40%
2340
16th to endDay
10%5%244345%6%9%44%
2447
September1st to 15thDay
12%425%5%35%46%8%40%
2082
16th to endDay
14%5%345%345%6%6%40%
1859
October1st to 15thDay
16%6%26%6%345%5%5%36%
1664
16th to endDay
24%9%47%5%345%45%25%
1760
November1st to 15thDay
14%6%26%5%36%447%37%
1537
16th to endDay
22%12%48%5%3446%6%20%
1440
December1st to 15thDay
20%17%6%9%7%45%446%15%
1440
16th to endDay
22%15%7%11%7%35%445%12%
1536
January1st to 15thNight
23%14%5%10%6%3443420%
2374
16th to endNight
16%15%8%9%6%4435%6%18%
2496
February1st to 15thNight
15%14%6%10%7%45%445%21%
2278
16th to endNight
17%11%5%7%7%3446%7%24%
1964
March1st to 15thNight
19%8%47%6%35%5%46%28%
2000
16th to endNight
16%9%345%25%5%46%36%
2112
April1st to 15thNight
21%7%45%424447%33%
1844
16th to endNight
11%5%26%5%35%45%7%41%
1620
May1st to 15thNight
15%5%26%6%35%5%6%8%34%
1619
16th to endNight
10%5%345%245%5%7%45%
1543
June1st to 15thNight
10%5%25%435%46%9%42%
1440
16th to endNight
9%5%24435%5%6%10%42%
1293
July1st to 15thNight
5%41443445%8%52%
1408
16th to endNight
7%32442446%10%47%
1703
August1st to 15thNight
5%3145%35%5%7%10%46%
1620
16th to endNight
8%41442445%7%51%
1743
September1st to 15thNight
10%5%244235%7%6%47%
1875
16th to endNight
12%3245%35%46%7%45%
1870
October1st to 15thNight
16%6%25%42445%6%42%
1966
16th to endNight
21%8%36%5%3346%6%29%
2112
November1st to 15thNight
14%5%26%5%3446%8%37%
2318
16th to endNight
22%11%37%6%35%45%6%22%
2520
December1st to 15thNight
23%14%6%7%6%3445%6%17%
2520
16th to endNight
22%14%6%9%7%44445%15%
2688

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
69%5%9%11%3
1562
16th to endDay
71%6%9%8%3
1728
February1st to 15thDay
66%6%9%13%3
1577
16th to endDay
62%7%11%13%4
1509
March1st to 15thDay
59%5%12%15%5%
1959
16th to endDay
53%410%20%9%1
2112
April1st to 15thDay
52%5%12%18%11%
2113
16th to endDay
44%6%11%19%15%2
2340
May1st to 15thDay
45%7%13%21%12%1
2331
16th to endDay
38%7%15%22%13%1
2574
June1st to 15thDay
38%7%14%25%13%1
2520
16th to endDay
36%8%16%23%14%
2660
July1st to 15thDay
31%7%13%28%18%1
2396
16th to endDay
33%9%17%24%13%1
2310
August1st to 15thDay
32%11%17%24%12%1
2327
16th to endDay
34%7%16%26%13%2
2447
September1st to 15thDay
40%7%14%25%11%
2082
16th to endDay
40%7%14%24%12%
1859
October1st to 15thDay
47%7%14%18%11%1
1664
16th to endDay
61%7%13%13%4
1760
November1st to 15thDay
46%8%14%19%9%1
1537
16th to endDay
62%7%11%14%3
1440
December1st to 15thDay
72%7%9%9%1
1440
16th to endDay
75%5%8%8%
1536
January1st to 15thNight
68%5%8%12%5%
2374
16th to endNight
66%6%10%13%2
2496
February1st to 15thNight
65%6%9%13%5%
2287
16th to endNight
58%6%11%17%5%
1964
March1st to 15thNight
55%6%10%20%6%1
2000
16th to endNight
47%5%9%21%12%2
2112
April1st to 15thNight
50%410%21%12%
1844
16th to endNight
40%5%9%22%18%4
1620
May1st to 15thNight
45%6%10%22%11%3
1620
16th to endNight
36%6%13%24%16%3
1545
June1st to 15thNight
36%6%12%28%14%1
1440
16th to endNight
35%6%13%24%17%1
1293
July1st to 15thNight
29%5%10%29%22%4
1327
16th to endNight
31%6%15%26%17%2
1595
August1st to 15thNight
29%8%14%30%14%1
1609
16th to endNight
31%5%12%30%17%2
1743
September1st to 15thNight
35%7%12%27%15%2
1875
16th to endNight
38%6%10%29%14%
1870
October1st to 15thNight
42%6%11%21%17%
1966
16th to endNight
55%6%12%17%6%
2112
November1st to 15thNight
44%8%12%20%11%1
2318
16th to endNight
61%7%12%15%3
2520
December1st to 15thNight
68%7%11%9%3
2520
16th to endNight
71%7%9%9%2
2688

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%23%37%9%8%1
81
16th to endDay
32%14%34%16%2
96
February1st to 15thDay
22%16%50%11%
90
16th to endDay
18%17%45%17%1
81
March1st to 15thDay
24%10%29%25%10%
249
16th to endDay
25%5%32%25%8%2
288
April1st to 15thDay
24%11%27%24%10%1
270
16th to endDay
20%5%28%23%14%7%
270
May1st to 15thDay
22%6%26%22%15%5%
288
16th to endDay
17%422%30%17%6%
331
June1st to 15thDay
14%421%35%20%3
315
16th to endDay
12%327%34%16%4
455
July1st to 15thDay
10%219%32%24%9%
373
16th to endDay
12%15%34%26%10%
326
August1st to 15thDay
9%16%31%27%14%
313
16th to endDay
15%114%27%24%16%
332
September1st to 15thDay
10%216%25%29%15%
315
16th to endDay
16%5%14%25%22%16%
270
October1st to 15thDay
17%6%21%29%20%5%
255
16th to endDay
27%11%28%24%6%
272
November1st to 15thDay
13%13%28%25%14%4
83
16th to endDay
26%18%31%15%6%1
60
December1st to 15thDay
28%21%33%11%5%
60
16th to endDay
28%26%34%10%
64
January1st to 15thNight
29%14%32%17%5%
720
16th to endNight
24%14%35%21%5%
768
February1st to 15thNight
23%15%33%23%3
704
16th to endNight
24%9%31%28%5%
631
March1st to 15thNight
23%7%33%25%9%
720
16th to endNight
20%5%32%29%12%1
768
April1st to 15thNight
23%8%31%28%7%
700
16th to endNight
14%431%34%12%1
540
May1st to 15thNight
18%323%35%17%1
540
16th to endNight
13%224%35%20%4
423
June1st to 15thNight
13%26%40%18%1
360
16th to endNight
12%120%42%21%1
360
July1st to 15thNight
6%216%42%28%3
380
16th to endNight
9%114%44%26%3
564
August1st to 15thNight
8%12%42%30%4
539
16th to endNight
9%115%34%33%5%
597
September1st to 15thNight
14%314%33%28%5%
720
16th to endNight
12%318%29%27%7%
677
October1st to 15thNight
19%6%20%31%19%3
660
16th to endNight
24%11%30%27%5%
704
November1st to 15thNight
17%8%29%29%12%1
700
16th to endNight
28%13%27%20%9%
720
December1st to 15thNight
30%15%32%16%4
720
16th to endNight
27%12%35%20%3
768
Page generated at 2017-09-21 07:18:10. Version ac04

Copyright 2017 A. Danko


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