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 2018-01-20.

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%
15464
14%
48325
10%
15427
42%
15427
18%
34121

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
15%
777
8%
2573
4%
776
20%
776
7%
2081
January16th to endNight
14%
788
9%
2560
3%
788
21%
788
8%
2076
February1st to 15thNight
16%
701
8%
2287
2%
701
24%
701
9%
1829
February16th to endNight
25%
631
11%
1964
5%
631
32%
631
13%
1503
March1st to 15thNight
26%
720
15%
2000
8%
720
33%
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
50%
360
14%
1440
16%
360
57%
360
24%
828
June16th to endNight
57%
360
17%
1293
16%
360
64%
360
27%
761
July1st to 15thNight
66%
380
18%
1327
21%
380
69%
380
34%
703
July16th to endNight
64%
564
15%
1595
14%
531
67%
531
35%
934
August1st to 15thNight
69%
539
18%
1609
14%
536
71%
536
34%
954
August16th to endNight
64%
597
24%
1743
17%
597
68%
597
36%
1024
September1st to 15thNight
59%
720
21%
1875
14%
720
62%
720
32%
1206
September16th to endNight
58%
717
23%
1980
17%
717
62%
717
30%
1258
October1st to 15thNight
47%
720
19%
2145
18%
720
50%
720
24%
1426
October16th to endNight
27%
768
14%
2304
9%
768
34%
768
15%
1697
November1st to 15thNight
38%
760
17%
2517
14%
760
44%
760
18%
1699
November16th to endNight
23%
780
10%
2730
6%
780
28%
780
10%
2084
December1st to 15thNight
15%
780
5%
2730
3%
780
18%
780
7%
2248
December16th to endNight
14%
832
6%
2912
1%
832
20%
832
6%
2462

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%
49182
Night
16%8%36%5%3445%7%33%
48509
Cloud CoverDay
14%8%36%5%35%45%7%33%
49192
Night
15%8%36%5%3445%7%33%
48513
TransparencyDay
48%7%13%19%10%1
48885
Night
50%6%11%20%10%1
48325
SeeingDay
17%6%24%26%17%6%
5892
Night
20%8%26%29%14%1
15471

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%410%7%45%446%17%
1692
16th to endDay
16%14%7%12%8%46%5%45%15%
1768
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%4244245%6%7%42%
1980
October1st to 15thDay
16%7%36%6%35%5%45%35%
1815
16th to endDay
24%10%36%5%34446%25%
1920
November1st to 15thDay
15%6%35%5%35%5%5%6%36%
1668
16th to endDay
21%12%47%6%345%5%5%22%
1560
December1st to 15thDay
20%16%5%9%8%34445%17%
1560
16th to endDay
23%14%7%11%7%35%44413%
1664
January1st to 15thNight
23%13%5%9%7%4443320%
2573
16th to endNight
16%16%7%10%6%3445%6%19%
2560
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
11%3244345%5%7%46%
1980
October1st to 15thNight
17%6%25%324447%41%
2145
16th to endNight
21%8%36%6%2345%6%30%
2304
November1st to 15thNight
16%5%26%5%35%47%6%36%
2517
16th to endNight
21%11%36%6%345%47%23%
2730
December1st to 15thNight
23%13%6%8%6%24447%18%
2730
16th to endNight
22%14%6%9%7%34446%16%
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
20%13%5%10%7%44346%17%
1692
16th to endDay
16%14%7%11%8%5%6%445%14%
1768
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
13%4345%345%6%6%42%
1980
October1st to 15thDay
16%6%27%6%35%5%5%5%35%
1815
16th to endDay
23%9%47%5%345%45%25%
1920
November1st to 15thDay
14%6%26%6%35%45%7%36%
1668
16th to endDay
21%12%47%5%35%46%6%21%
1560
December1st to 15thDay
19%16%6%10%6%45%446%16%
1560
16th to endDay
22%15%7%11%7%35%44413%
1664
January1st to 15thNight
22%13%5%9%7%3443420%
2573
16th to endNight
16%15%8%9%6%4435%6%18%
2560
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
11%3245%35%45%7%46%
1980
October1st to 15thNight
17%6%25%42445%6%41%
2145
16th to endNight
20%8%37%5%3346%6%30%
2304
November1st to 15thNight
16%5%26%5%3446%8%36%
2517
16th to endNight
21%10%37%6%35%45%6%23%
2730
December1st to 15thNight
22%14%6%7%6%3445%6%17%
2730
16th to endNight
22%14%6%8%7%44445%16%
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
68%5%9%11%4
1693
16th to endDay
71%7%9%8%3
1768
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
39%7%14%25%12%
1980
October1st to 15thDay
48%7%13%18%11%1
1815
16th to endDay
60%7%13%13%5%
1920
November1st to 15thDay
47%7%14%19%8%1
1668
16th to endDay
61%7%12%14%3
1560
December1st to 15thDay
71%6%9%10%2
1560
16th to endDay
74%5%8%9%1
1664
January1st to 15thNight
68%48%12%5%
2573
16th to endNight
66%6%10%13%2
2560
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
37%6%10%29%15%
1980
October1st to 15thNight
43%6%10%22%17%
2145
16th to endNight
54%6%12%18%7%
2304
November1st to 15thNight
45%8%12%20%11%1
2517
16th to endNight
59%6%12%15%4
2730
December1st to 15thNight
68%7%11%10%3
2730
16th to endNight
71%6%8%10%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
22%18%32%16%9%
122
16th to endDay
28%14%40%14%1
109
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
14%5%14%24%23%18%
314
October1st to 15thDay
18%6%20%28%19%6%
315
16th to endDay
25%11%29%23%8%
336
November1st to 15thDay
17%10%32%21%14%3
124
16th to endDay
23%15%38%14%6%1
90
December1st to 15thDay
23%20%34%16%5%
90
16th to endDay
28%22%33%13%2
96
January1st to 15thNight
29%14%32%17%5%
780
16th to endNight
23%15%35%20%5%
788
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%28%28%8%
717
October1st to 15thNight
20%6%19%30%19%3
720
16th to endNight
23%12%29%27%6%
768
November1st to 15thNight
19%8%28%29%12%1
760
16th to endNight
27%14%28%19%9%
780
December1st to 15thNight
30%15%32%16%5%
780
16th to endNight
28%12%34%21%3
832
Page generated at 2018-01-21 12:19:32. Version ac04

Copyright 2018 A. Danko


Port Burwell Provincial Park Clear Sky Chart |Charts Home