Porteau Cove Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Porteau Cove Provincial Park clear sky chart from 2005-11-05 to 2017-10-31.

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%
14648
8%
47259
6%
14618
34%
14618
12%
36524

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
21%
750
10%
2686
8%
746
25%
746
8%
2235
January16th to endNight
23%
783
8%
2768
6%
783
26%
783
8%
2238
February1st to 15thNight
21%
701
6%
2288
4%
699
24%
699
8%
1904
February16th to endNight
23%
632
10%
2052
5%
632
29%
632
11%
1609
March1st to 15thNight
17%
720
4%
2055
2%
720
18%
720
7%
1795
March16th to endNight
19%
768
5%
2079
2%
768
21%
768
8%
1821
April1st to 15thNight
28%
704
5%
1784
3%
704
29%
704
11%
1509
April16th to endNight
28%
505
7%
1585
4%
505
31%
505
11%
1276
May1st to 15thNight
46%
360
10%
1440
16%
360
48%
360
15%
989
May16th to endNight
44%
374
5%
1433
8%
374
46%
374
13%
1055
June1st to 15thNight
40%
360
2%
1260
1%
360
41%
360
15%
924
June16th to endNight
43%
360
4%
1260
1%
360
44%
360
13%
940
July1st to 15thNight
67%
340
8%
1190
6%
340
69%
340
32%
653
July16th to endNight
72%
376
13%
1307
19%
354
74%
354
34%
677
August1st to 15thNight
73%
432
14%
1504
19%
430
73%
430
33%
806
August16th to endNight
64%
602
17%
1748
14%
602
65%
602
31%
1079
September1st to 15thNight
63%
720
21%
1800
12%
720
65%
720
41%
1097
September16th to endNight
40%
716
15%
1978
10%
716
42%
716
18%
1471
October1st to 15thNight
35%
720
10%
2160
8%
720
38%
720
17%
1576
October16th to endNight
25%
768
7%
2413
5%
768
28%
768
9%
1974
November1st to 15thNight
11%
700
5%
2450
3%
700
14%
700
5%
2170
November16th to endNight
17%
720
6%
2520
3%
720
21%
720
7%
2081
December1st to 15thNight
16%
737
6%
2619
2%
737
21%
737
7%
2160
December16th to endNight
10%
800
6%
2880
2%
800
15%
800
5%
2485

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
27%10%35%5%24345%27%
48523
Night
29%10%35%423335%27%
47410
Cloud CoverDay
30%11%35%42333425%
48523
Night
31%11%35%42333426%
47413
TransparencyDay
63%5%10%13%5%1
48178
Night
61%5%10%13%6%1
47259
SeeingDay
33%11%21%23%7%2
6353
Night
36%6%18%22%14%2
14652

By Month

Percentage Cloud Cover NW (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
43%10%3441332318%
1253
16th to endDay
36%13%35%42323319%
1453
February1st to 15thDay
36%12%36%5%22345%16%
1576
16th to endDay
25%16%46%5%2445%5%20%
1421
March1st to 15thDay
42%15%45%5%2333212%
1905
16th to endDay
36%16%47%6%3323214%
2145
April1st to 15thDay
28%15%5%8%7%35%33413%
2162
16th to endDay
31%11%47%6%46%34415%
2374
May1st to 15thDay
21%9%47%6%35%446%26%
2511
16th to endDay
25%9%47%6%35%45%6%21%
2675
June1st to 15thDay
28%9%46%5%34345%23%
2700
16th to endDay
26%9%37%6%35%345%24%
2700
July1st to 15thDay
12%5%25%424445%48%
2700
16th to endDay
12%5%2342345%6%48%
2772
August1st to 15thDay
12%5%24423336%51%
2447
16th to endDay
13%6%15%5%2445%7%43%
2453
September1st to 15thDay
12%5%24334445%48%
2160
16th to endDay
29%6%35%43443429%
1978
October1st to 15thDay
31%7%15%42443430%
1800
16th to endDay
39%9%24423336%19%
1807
November1st to 15thDay
50%9%25%42233312%
1408
16th to endDay
39%12%2442432220%
1440
December1st to 15thDay
33%15%4432333323%
1339
16th to endDay
41%19%3431222116%
1344
January1st to 15thNight
41%10%25%42223419%
2686
16th to endNight
34%12%35%5%22336%19%
2768
February1st to 15thNight
36%11%35%5%33345%18%
2276
16th to endNight
28%15%45%42433325%
2052
March1st to 15thNight
40%16%35%42322315%
2055
16th to endNight
37%15%35%5%2433316%
2075
April1st to 15thNight
28%12%45%6%3444420%
1784
16th to endNight
27%10%46%5%25%335%23%
1585
May1st to 15thNight
19%6%35%435%5%6%6%34%
1439
16th to endNight
18%8%46%6%35%45%7%29%
1433
June1st to 15thNight
23%9%35%433335%33%
1260
16th to endNight
20%7%37%6%35%445%31%
1260
July1st to 15thNight
10%42332325%6%55%
1260
16th to endNight
9%312324446%58%
1397
August1st to 15thNight
8%31332245%5%56%
1512
16th to endNight
11%41442335%9%48%
1748
September1st to 15thNight
9%314322345%58%
1800
16th to endNight
26%9%25%413436%32%
1978
October1st to 15thNight
26%6%24424335%34%
2160
16th to endNight
38%7%35%42433421%
2413
November1st to 15thNight
48%11%25%32222314%
2450
16th to endNight
37%11%36%5%3322321%
2520
December1st to 15thNight
32%15%45%42343319%
2619
16th to endNight
40%16%4442222316%
2880

Percentage Cloud Cover SW (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
44%12%25%41323316%
1253
16th to endDay
37%15%3442322418%
1453
February1st to 15thDay
37%15%45%42333415%
1576
16th to endDay
27%19%5%5%42244418%
1421
March1st to 15thDay
44%17%45%31233310%
1905
16th to endDay
38%21%5%5%42222311%
2145
April1st to 15thDay
32%19%5%7%6%3323411%
2162
16th to endDay
34%14%5%8%6%3442412%
2374
May1st to 15thDay
25%12%46%6%245%45%22%
2511
16th to endDay
32%10%35%6%35%44418%
2675
June1st to 15thDay
34%10%36%423445%19%
2700
16th to endDay
31%10%37%5%3433422%
2700
July1st to 15thDay
15%6%24424346%44%
2700
16th to endDay
16%5%23323345%46%
2772
August1st to 15thDay
14%6%24323246%47%
2447
16th to endDay
16%7%25%32346%6%40%
2453
September1st to 15thDay
14%7%33433445%47%
2160
16th to endDay
32%7%35%423335%27%
1978
October1st to 15thDay
34%6%35%32334428%
1800
16th to endDay
43%9%25%31323418%
1807
November1st to 15thDay
53%11%25%31222211%
1408
16th to endDay
41%13%3432332119%
1440
December1st to 15thDay
35%16%4332223222%
1339
16th to endDay
40%21%4431222213%
1344
January1st to 15thNight
42%12%3441233218%
2685
16th to endNight
36%13%35%413336%17%
2768
February1st to 15thNight
36%13%35%42334417%
2276
16th to endNight
29%16%35%42223324%
2052
March1st to 15thNight
41%19%35%31233214%
2055
16th to endNight
38%16%36%41333314%
2079
April1st to 15thNight
29%15%46%42445%418%
1784
16th to endNight
30%12%45%5%24245%20%
1585
May1st to 15thNight
22%5%245%25%5%6%6%33%
1439
16th to endNight
22%8%36%6%35%447%27%
1433
June1st to 15thNight
26%8%27%423336%30%
1260
16th to endNight
23%7%46%5%35%45%429%
1260
July1st to 15thNight
11%41331335%6%54%
1260
16th to endNight
11%313223445%57%
1397
August1st to 15thNight
10%413314445%56%
1512
16th to endNight
12%5%2342336%8%46%
1748
September1st to 15thNight
10%313423345%56%
1800
16th to endNight
29%7%34413336%31%
1978
October1st to 15thNight
28%7%2442343433%
2160
16th to endNight
40%8%2432443419%
2413
November1st to 15thNight
52%10%3431322312%
2450
16th to endNight
38%14%35%42222320%
2520
December1st to 15thNight
33%15%45%42433319%
2619
16th to endNight
40%19%3431222314%
2880

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
73%3410%5%2
1253
16th to endDay
72%37%10%32
1453
February1st to 15thDay
73%47%7%42
1576
16th to endDay
69%48%11%4
1421
March1st to 15thDay
80%36%6%1
1905
16th to endDay
80%36%8%1
2145
April1st to 15thDay
77%46%8%1
2162
16th to endDay
76%5%7%7%3
2374
May1st to 15thDay
62%6%11%13%4
2511
16th to endDay
68%6%9%12%2
2679
June1st to 15thDay
66%6%12%9%31
2700
16th to endDay
65%5%10%13%4
2700
July1st to 15thDay
41%6%14%22%13%1
2541
16th to endDay
37%5%16%26%11%1
2599
August1st to 15thDay
38%5%14%28%10%2
2430
16th to endDay
42%6%18%24%6%1
2453
September1st to 15thDay
39%412%23%16%3
2160
16th to endDay
60%49%15%7%2
1978
October1st to 15thDay
59%5%12%14%7%
1800
16th to endDay
70%411%9%5%
1807
November1st to 15thDay
81%26%5%21
1408
16th to endDay
74%348%7%1
1440
December1st to 15thDay
69%5%6%8%7%2
1339
16th to endDay
79%346%42
1344
January1st to 15thNight
71%4312%5%2
2686
16th to endNight
69%48%10%43
2768
February1st to 15thNight
70%5%7%10%32
2288
16th to endNight
65%39%14%5%1
2052
March1st to 15thNight
76%47%8%2
2055
16th to endNight
75%48%10%1
2079
April1st to 15thNight
68%6%10%12%2
1784
16th to endNight
66%5%12%11%4
1585
May1st to 15thNight
49%8%16%18%6%
1440
16th to endNight
56%6%16%15%4
1433
June1st to 15thNight
55%6%19%11%5%1
1260
16th to endNight
56%8%12%16%41
1260
July1st to 15thNight
30%6%21%25%14%2
1190
16th to endNight
26%7%17%30%14%2
1307
August1st to 15thNight
28%7%21%26%13%3
1504
16th to endNight
35%7%20%23%9%3
1748
September1st to 15thNight
29%6%16%25%18%4
1800
16th to endNight
55%5%11%18%7%2
1978
October1st to 15thNight
54%5%12%16%11%
2160
16th to endNight
68%5%8%11%6%
2413
November1st to 15thNight
79%446%22
2450
16th to endNight
72%36%8%7%1
2520
December1st to 15thNight
71%47%9%5%1
2619
16th to endNight
77%346%5%1
2880

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
20%321%28%18%8%
60
16th to endDay
62%5%11%15%31
77
February1st to 15thDay
51%6%19%16%6%
236
16th to endDay
37%13%18%20%9%
211
March1st to 15thDay
57%14%19%7%
270
16th to endDay
53%12%20%9%31
288
April1st to 15thDay
44%18%14%14%5%2
269
16th to endDay
39%17%20%18%21
270
May1st to 15thDay
31%17%24%20%41
288
16th to endDay
33%13%16%24%9%2
390
June1st to 15thDay
32%16%21%22%6%1
495
16th to endDay
28%15%26%23%5%1
495
July1st to 15thDay
17%11%21%40%7%2
475
16th to endDay
13%12%25%35%9%2
441
August1st to 15thDay
15%6%23%34%13%6%
315
16th to endDay
15%8%27%33%10%3
332
September1st to 15thDay
21%11%26%26%11%2
315
16th to endDay
32%9%22%22%8%4
315
October1st to 15thDay
39%6%25%17%9%1
315
16th to endDay
51%5%13%17%9%1
252
November1st to 15thDay
63%11%11%11%1
60
16th to endDay
43%5%15%13%6%16%
60
December1st to 15thDay
63%5%11%15%5%
60
16th to endDay
50%423%10%10%
64
January1st to 15thNight
46%7%17%19%7%1
750
16th to endNight
42%7%21%20%7%
783
February1st to 15thNight
43%5%22%23%5%
704
16th to endNight
37%9%22%21%8%
632
March1st to 15thNight
51%8%17%15%6%
720
16th to endNight
48%6%18%18%7%2
768
April1st to 15thNight
37%7%18%25%8%1
704
16th to endNight
36%7%20%23%9%2
505
May1st to 15thNight
23%416%32%19%3
360
16th to endNight
25%5%14%32%21%1
375
June1st to 15thNight
28%6%14%25%22%2
360
16th to endNight
24%8%12%30%23%1
360
July1st to 15thNight
12%39%33%35%6%
340
16th to endNight
10%27%28%42%7%
376
August1st to 15thNight
12%15%29%40%10%
432
16th to endNight
16%211%29%36%4
602
September1st to 15thNight
12%413%29%33%6%
720
16th to endNight
33%413%26%18%3
716
October1st to 15thNight
32%421%21%17%1
720
16th to endNight
46%5%19%19%7%1
768
November1st to 15thNight
56%6%20%13%2
700
16th to endNight
44%9%21%14%8%2
720
December1st to 15thNight
41%8%27%19%3
737
16th to endNight
52%8%23%13%1
800
Page generated at 2017-11-01 14:23:32. Version ac04

Copyright 2017 A. Danko


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