Petawawa Terrace Provincial Nature Reserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Petawawa Terrace Provincial Nature Reserve clear sky chart from 2005-11-05 to 2017-09-19.

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
32%
14630
12%
46888
9%
14600
38%
14600
16%
33897

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%
720
5%
2506
3%
716
21%
716
6%
2083
January16th to endNight
26%
768
11%
2605
6%
768
33%
768
12%
1972
February1st to 15thNight
20%
702
9%
2287
5%
701
26%
701
11%
1809
February16th to endNight
22%
631
12%
1995
6%
631
31%
631
13%
1517
March1st to 15thNight
23%
720
12%
2052
7%
720
29%
720
14%
1596
March16th to endNight
34%
768
19%
2069
10%
768
41%
768
23%
1427
April1st to 15thNight
28%
718
14%
1796
6%
718
33%
718
20%
1344
April16th to endNight
33%
615
17%
1695
9%
615
39%
615
23%
1198
May1st to 15thNight
34%
363
17%
1443
17%
363
41%
363
17%
944
May16th to endNight
39%
375
13%
1497
11%
374
48%
374
18%
942
June1st to 15thNight
38%
360
8%
1440
6%
360
46%
360
17%
948
June16th to endNight
45%
360
9%
1440
12%
360
50%
360
18%
923
July1st to 15thNight
54%
340
14%
1360
21%
340
58%
340
26%
771
July16th to endNight
57%
376
14%
1418
16%
354
62%
354
26%
806
August1st to 15thNight
58%
486
15%
1557
13%
484
60%
484
26%
958
August16th to endNight
56%
663
20%
1809
12%
663
60%
663
35%
1121
September1st to 15thNight
45%
720
15%
1800
7%
720
48%
720
29%
1256
September16th to endNight
48%
673
19%
1853
13%
673
52%
673
31%
1203
October1st to 15thNight
31%
660
17%
1980
12%
660
39%
660
19%
1403
October16th to endNight
26%
704
10%
2167
5%
704
32%
704
12%
1711
November1st to 15thNight
30%
700
15%
2391
12%
700
36%
700
14%
1727
November16th to endNight
23%
720
8%
2520
6%
720
26%
720
9%
1970
December1st to 15thNight
17%
720
6%
2520
3%
720
21%
720
7%
2060
December16th to endNight
17%
768
8%
2688
4%
768
21%
768
7%
2208

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
18%9%46%5%35%45%6%31%
47935
Night
18%10%46%5%34445%31%
47058
TransparencyDay
52%5%11%19%9%1
47623
Night
53%5%11%19%9%
46888
SeeingDay
21%9%26%24%13%4
5387
Night
23%9%26%28%11%
14632

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
22%15%6%10%6%3233421%
1432
16th to endDay
14%16%5%8%7%45%435%23%
1617
February1st to 15thDay
11%15%6%12%7%46%445%19%
1575
16th to endDay
16%15%6%8%5%44446%23%
1477
March1st to 15thDay
17%13%46%6%36%445%27%
1895
16th to endDay
13%7%5%6%43435%6%38%
2154
April1st to 15thDay
23%10%45%42424432%
2152
16th to endDay
21%7%25%42443437%
2274
May1st to 15thDay
20%9%35%5%3435%5%32%
2508
16th to endDay
17%6%35%5%35%5%46%35%
2618
June1st to 15thDay
20%6%36%5%45%45%6%30%
2520
16th to endDay
15%6%35%6%36%5%6%8%34%
2520
July1st to 15thDay
14%425%5%35%5%7%7%36%
2520
16th to endDay
11%5%25%6%37%5%6%10%35%
2654
August1st to 15thDay
12%6%26%6%36%5%5%7%36%
2391
16th to endDay
12%6%25%5%35%5%6%9%38%
2381
September1st to 15thDay
17%5%35%43345%7%38%
2160
16th to endDay
16%6%35%424336%42%
1851
October1st to 15thDay
21%8%25%6%24445%32%
1650
16th to endDay
30%9%37%6%33435%23%
1704
November1st to 15thDay
18%9%36%6%34445%32%
1466
16th to endDay
27%13%5%7%6%25%33319%
1440
December1st to 15thDay
22%15%6%8%7%45%445%14%
1440
16th to endDay
22%18%7%8%5%2333419%
1536
January1st to 15thNight
19%17%7%10%7%45%34416%
2506
16th to endNight
14%16%5%8%6%35%445%25%
2605
February1st to 15thNight
13%13%6%11%7%36%5%45%22%
2285
16th to endNight
16%13%5%9%7%3435%426%
1995
March1st to 15thNight
18%13%48%6%3443427%
2040
16th to endNight
14%9%45%5%23336%40%
2069
April1st to 15thNight
22%10%36%424335%33%
1796
16th to endNight
19%8%35%5%24336%37%
1695
May1st to 15thNight
21%7%36%423346%35%
1443
16th to endNight
15%5%25%7%26%45%5%39%
1495
June1st to 15thNight
18%6%25%5%2445%8%35%
1440
16th to endNight
15%5%245%35%5%7%8%35%
1440
July1st to 15thNight
10%3245%445%5%7%46%
1440
16th to endNight
11%423435%5%6%8%45%
1514
August1st to 15thNight
10%5%25%3345%6%8%43%
1567
16th to endNight
9%4244245%5%8%47%
1809
September1st to 15thNight
14%6%36%5%24346%41%
1800
16th to endNight
16%6%14423345%46%
1853
October1st to 15thNight
22%7%35%5%33345%36%
1980
16th to endNight
26%11%25%7%35%345%24%
2167
November1st to 15thNight
19%10%36%5%44446%31%
2391
16th to endNight
24%13%5%8%5%2343323%
2520
December1st to 15thNight
22%17%6%8%5%3443418%
2520
16th to endNight
24%17%6%8%5%3443417%
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
68%48%12%5%
1433
16th to endDay
64%49%14%6%1
1617
February1st to 15thDay
65%410%14%4
1577
16th to endDay
61%5%8%14%9%
1477
March1st to 15thDay
59%410%16%7%1
1906
16th to endDay
46%310%20%14%4
2154
April1st to 15thDay
55%37%18%12%2
2152
16th to endDay
49%46%20%16%3
2274
May1st to 15thDay
52%5%8%17%14%2
2508
16th to endDay
48%5%10%20%12%2
2622
June1st to 15thDay
52%7%10%19%9%
2520
16th to endDay
46%7%11%20%12%1
2520
July1st to 15thDay
40%7%11%25%13%1
2371
16th to endDay
42%7%15%23%9%
2487
August1st to 15thDay
45%7%15%20%10%
2377
16th to endDay
41%6%16%25%8%
2381
September1st to 15thDay
43%6%14%24%10%
2160
16th to endDay
43%412%31%7%
1851
October1st to 15thDay
53%6%12%18%9%
1650
16th to endDay
64%411%14%4
1704
November1st to 15thDay
52%6%14%19%7%
1466
16th to endDay
67%6%9%11%41
1440
December1st to 15thDay
72%6%8%9%2
1440
16th to endDay
69%5%8%11%4
1536
January1st to 15thNight
71%5%9%9%3
2506
16th to endNight
60%5%10%15%7%
2605
February1st to 15thNight
64%410%15%4
2287
16th to endNight
60%5%8%18%7%
1995
March1st to 15thNight
60%48%18%7%
2052
16th to endNight
46%49%19%16%2
2069
April1st to 15thNight
53%47%17%13%2
1796
16th to endNight
48%47%20%15%3
1695
May1st to 15thNight
49%36%20%16%3
1443
16th to endNight
43%7%12%21%13%2
1497
June1st to 15thNight
45%8%13%21%10%1
1440
16th to endNight
44%7%12%21%13%
1440
July1st to 15thNight
34%7%13%25%17%1
1360
16th to endNight
35%6%15%29%12%
1418
August1st to 15thNight
36%8%16%25%12%
1557
16th to endNight
32%7%17%31%10%
1809
September1st to 15thNight
43%5%13%26%11%
1800
16th to endNight
39%5%14%33%7%
1853
October1st to 15thNight
50%5%9%22%11%
1980
16th to endNight
62%5%11%15%4
2167
November1st to 15thNight
54%6%12%17%9%
2391
16th to endNight
65%412%13%3
2520
December1st to 15thNight
68%5%11%11%3
2520
16th to endNight
70%49%10%5%
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
28%15%28%25%3
60
16th to endDay
44%331%11%9%
77
February1st to 15thDay
30%15%35%18%
90
16th to endDay
34%13%26%22%2
136
March1st to 15thDay
25%12%30%24%6%
270
16th to endDay
19%13%28%24%10%2
288
April1st to 15thDay
27%12%31%15%9%2
270
16th to endDay
26%11%27%17%12%4
270
May1st to 15thDay
32%9%21%22%9%4
288
16th to endDay
18%11%34%21%12%2
331
June1st to 15thDay
26%8%28%21%12%2
315
16th to endDay
14%9%27%28%15%4
315
July1st to 15thDay
14%5%23%33%17%4
305
16th to endDay
9%327%33%19%6%
326
August1st to 15thDay
14%421%30%21%8%
313
16th to endDay
15%322%28%18%12%
332
September1st to 15thDay
17%5%20%22%18%14%
315
16th to endDay
16%7%22%22%22%7%
266
October1st to 15thDay
27%8%24%23%14%1
255
16th to endDay
31%14%22%21%8%
261
November1st to 15thDay
17%9%33%25%14%
120
16th to endDay
41%10%23%16%5%3
60
December1st to 15thDay
13%16%38%20%10%1
60
16th to endDay
40%12%35%9%1
64
January1st to 15thNight
27%12%28%24%6%
720
16th to endNight
23%9%29%28%8%
768
February1st to 15thNight
19%10%36%25%6%
704
16th to endNight
23%10%33%23%8%
631
March1st to 15thNight
27%11%29%26%4
720
16th to endNight
19%13%27%27%12%
768
April1st to 15thNight
27%12%27%26%5%
718
16th to endNight
22%9%29%26%11%
615
May1st to 15thNight
25%6%26%29%11%1
363
16th to endNight
16%8%29%33%11%
375
June1st to 15thNight
20%428%35%10%
360
16th to endNight
18%6%23%38%14%
360
July1st to 15thNight
10%321%44%18%1
340
16th to endNight
11%323%43%18%1
376
August1st to 15thNight
12%217%38%26%2
486
16th to endNight
10%420%39%23%1
663
September1st to 15thNight
18%325%28%21%2
720
16th to endNight
20%5%19%29%22%2
673
October1st to 15thNight
26%8%27%24%12%
660
16th to endNight
31%10%24%25%7%
704
November1st to 15thNight
23%11%26%25%12%
700
16th to endNight
29%15%23%23%7%
720
December1st to 15thNight
29%13%29%22%4
720
16th to endNight
34%10%27%22%5%
768
Page generated at 2017-09-20 04:49:52. Version ac04

Copyright 2017 A. Danko


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