This page made possible by the sponsorship of: Remembering Eric Eddison.

Corner Brook
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Corner Brook clear sky chart from 2005-11-05 to 2018-02-22.

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
20%
15839
5%
48958
3%
15798
22%
15798
8%
41622

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
6%
822
2%
2716
1%
821
8%
821
2%
2562
January16th to endNight
11%
880
2%
2912
2%
880
12%
880
2%
2716
February1st to 15thNight
8%
790
1%
2604
0%
789
9%
789
2%
2463
February16th to endNight
16%
659
2%
1997
1%
659
18%
659
6%
1773
March1st to 15thNight
18%
717
7%
2148
4%
716
20%
716
6%
1874
March16th to endNight
19%
618
7%
2007
4%
618
23%
618
7%
1707
April1st to 15thNight
19%
539
6%
1796
5%
539
22%
539
8%
1484
April16th to endNight
24%
540
9%
1616
7%
540
27%
540
10%
1288
May1st to 15thNight
32%
540
8%
1440
5%
540
33%
540
17%
1108
May16th to endNight
29%
561
7%
1448
3%
560
31%
560
15%
1159
June1st to 15thNight
32%
540
2%
1260
1%
540
33%
540
14%
1039
June16th to endNight
31%
540
3%
1260
2%
540
32%
540
18%
995
July1st to 15thNight
33%
510
3%
1292
3%
510
34%
510
20%
959
July16th to endNight
35%
565
7%
1419
4%
532
38%
532
18%
1071
August1st to 15thNight
36%
539
7%
1429
2%
535
38%
535
19%
1081
August16th to endNight
37%
573
8%
1800
7%
573
39%
573
16%
1317
September1st to 15thNight
28%
540
6%
1800
6%
540
31%
540
12%
1363
September16th to endNight
22%
538
10%
1980
7%
538
28%
538
11%
1480
October1st to 15thNight
20%
677
7%
2129
3%
677
25%
677
10%
1707
October16th to endNight
19%
816
6%
2496
3%
816
21%
816
6%
2128
November1st to 15thNight
16%
805
6%
2522
4%
805
18%
805
6%
2183
November16th to endNight
13%
825
4%
2847
2%
825
15%
825
4%
2509
December1st to 15thNight
10%
825
2%
2925
0%
825
12%
825
2%
2708
December16th to endNight
10%
880
2%
3115
2%
880
10%
880
1%
2948

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
20%14%6%10%8%34345%18%
49290
Night
18%16%7%11%9%4433415%
49140
TransparencyDay
69%49%12%4
48978
Night
72%48%10%3
48970
SeeingDay
29%18%24%17%8%2
8503
Night
29%17%23%20%7%1
15847

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
13%17%11%23%15%442114
1552
16th to endDay
11%15%10%19%21%6%42114
1664
February1st to 15thDay
14%12%8%16%19%7%5%4325%
1586
16th to endDay
12%19%10%18%12%4421210%
1623
March1st to 15thDay
14%19%8%11%10%5%5%43413%
1790
16th to endDay
15%19%10%11%9%4432314%
2217
April1st to 15thDay
18%17%7%13%8%3334415%
2153
16th to endDay
18%15%5%9%6%2433424%
2343
May1st to 15thDay
22%12%47%5%2334427%
2512
16th to endDay
25%13%47%5%24345%22%
2663
June1st to 15thDay
26%10%37%6%35%45%6%20%
2700
16th to endDay
24%10%47%5%3445%6%25%
2700
July1st to 15thDay
17%8%36%5%25%5%5%8%31%
2586
16th to endDay
21%10%37%6%3445%6%25%
2653
August1st to 15thDay
20%8%38%6%445%6%7%25%
2520
16th to endDay
26%8%26%6%2445%7%24%
2400
September1st to 15thDay
27%10%36%5%24346%25%
2160
16th to endDay
24%12%46%6%2445%7%21%
1980
October1st to 15thDay
26%13%45%5%23345%25%
1829
16th to endDay
29%22%6%8%42322213%
1728
November1st to 15thDay
22%29%7%8%5%2322411%
1666
16th to endDay
14%25%10%12%6%344448%
1441
December1st to 15thDay
16%20%10%22%8%35%3223
1365
16th to endDay
18%20%12%17%14%322115%
1459
January1st to 15thNight
14%20%11%19%14%442124
2716
16th to endNight
11%14%9%19%19%7%5%4224
2912
February1st to 15thNight
13%15%8%17%20%7%6%2124
2603
16th to endNight
11%16%9%17%13%45%32311%
1997
March1st to 15thNight
13%16%7%11%12%6%6%43313%
2147
16th to endNight
14%19%8%12%9%4443314%
2007
April1st to 15thNight
17%19%8%9%7%34345%16%
1796
16th to endNight
14%13%7%12%7%34445%21%
1616
May1st to 15thNight
20%12%36%425%446%28%
1440
16th to endNight
28%10%35%424446%24%
1446
June1st to 15thNight
24%8%5%7%6%445%47%20%
1260
16th to endNight
21%9%46%5%246%5%6%27%
1260
July1st to 15thNight
17%8%38%5%3436%8%30%
1371
16th to endNight
21%8%47%5%35%45%7%27%
1515
August1st to 15thNight
17%8%46%6%36%5%6%7%26%
1440
16th to endNight
20%8%36%5%35%45%7%28%
1800
September1st to 15thNight
25%9%46%5%24435%27%
1800
16th to endNight
22%11%47%5%3345%6%24%
1980
October1st to 15thNight
23%15%36%6%34446%21%
2129
16th to endNight
25%21%48%6%2343414%
2496
November1st to 15thNight
20%24%6%8%6%3434412%
2522
16th to endNight
18%21%10%12%6%343349%
2847
December1st to 15thNight
15%23%11%18%9%332225%
2925
16th to endNight
15%21%14%19%12%332114
3115

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
89%233
1553
16th to endDay
89%2231
1664
February1st to 15thDay
84%35%5%
1589
16th to endDay
83%136%3
1623
March1st to 15thDay
75%45%10%3
1800
16th to endDay
76%35%10%4
2217
April1st to 15thDay
73%37%10%4
2153
16th to endDay
64%37%14%9%
2343
May1st to 15thDay
60%48%17%8%
2512
16th to endDay
65%410%14%5%
2667
June1st to 15thDay
65%5%9%14%4
2700
16th to endDay
60%5%12%16%5%
2700
July1st to 15thDay
50%6%15%22%5%
2437
16th to endDay
59%5%12%18%3
2486
August1st to 15thDay
56%8%13%16%3
2506
16th to endDay
59%6%14%15%3
2400
September1st to 15thDay
60%312%16%5%
2160
16th to endDay
62%5%13%14%4
1980
October1st to 15thDay
61%5%12%14%5%
1829
16th to endDay
78%36%8%2
1728
November1st to 15thDay
79%37%7%1
1666
16th to endDay
79%5%6%6%2
1441
December1st to 15thDay
87%334
1365
16th to endDay
89%2231
1459
January1st to 15thNight
88%234
2716
16th to endNight
87%2431
2912
February1st to 15thNight
89%243
2604
16th to endNight
79%36%7%3
1997
March1st to 15thNight
75%35%11%2
2160
16th to endNight
73%47%10%4
2007
April1st to 15thNight
70%48%12%3
1796
16th to endNight
64%5%8%13%7%
1616
May1st to 15thNight
56%6%11%18%6%1
1440
16th to endNight
60%6%10%16%5%
1448
June1st to 15thNight
61%7%12%14%4
1260
16th to endNight
56%7%13%16%6%
1260
July1st to 15thNight
51%6%17%20%4
1292
16th to endNight
55%413%20%4
1419
August1st to 15thNight
53%7%18%17%3
1429
16th to endNight
54%6%18%17%3
1800
September1st to 15thNight
59%5%14%16%4
1800
16th to endNight
59%5%14%14%5%
1980
October1st to 15thNight
64%5%12%10%6%
2129
16th to endNight
74%38%9%3
2496
November1st to 15thNight
74%49%9%1
2522
16th to endNight
80%37%6%2
2847
December1st to 15thNight
86%35%4
2925
16th to endNight
89%3231
3115

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%38%26%9%21
285
16th to endDay
28%26%22%16%5%
304
February1st to 15thDay
27%30%21%14%4
281
16th to endDay
26%23%26%11%9%3
232
March1st to 15thDay
24%27%24%16%5%2
240
16th to endDay
28%28%21%11%6%2
281
April1st to 15thDay
31%28%21%12%41
270
16th to endDay
27%18%23%18%8%2
429
May1st to 15thDay
30%11%21%20%12%3
468
16th to endDay
31%14%22%18%10%2
519
June1st to 15thDay
33%11%21%21%10%2
495
16th to endDay
30%14%27%15%8%2
495
July1st to 15thDay
21%13%30%21%11%2
475
16th to endDay
27%10%23%23%12%1
514
August1st to 15thDay
22%13%26%23%11%2
493
16th to endDay
28%10%23%24%10%3
426
September1st to 15thDay
34%13%32%14%4
315
16th to endDay
34%19%26%15%31
269
October1st to 15thDay
34%19%24%12%6%3
270
16th to endDay
40%19%16%11%9%1
288
November1st to 15thDay
38%19%18%15%6%2
280
16th to endDay
30%23%23%15%5%1
285
December1st to 15thDay
31%27%23%12%4
285
16th to endDay
30%26%24%12%41
304
January1st to 15thNight
27%29%24%14%2
825
16th to endNight
24%26%26%16%5%
880
February1st to 15thNight
27%25%26%16%3
792
16th to endNight
26%18%25%18%8%2
659
March1st to 15thNight
25%24%21%20%8%
720
16th to endNight
25%18%25%22%7%
618
April1st to 15thNight
30%18%22%20%7%
539
16th to endNight
23%15%24%26%8%1
540
May1st to 15thNight
27%10%23%26%9%2
540
16th to endNight
34%9%21%22%10%1
561
June1st to 15thNight
27%8%20%29%12%
540
16th to endNight
27%9%25%26%10%2
540
July1st to 15thNight
21%10%28%25%13%1
510
16th to endNight
25%8%20%32%12%
565
August1st to 15thNight
24%9%23%26%16%
539
16th to endNight
24%7%23%25%15%2
573
September1st to 15thNight
33%13%19%24%7%
540
16th to endNight
31%13%25%23%5%
538
October1st to 15thNight
35%14%22%18%7%1
677
16th to endNight
39%18%16%18%7%
816
November1st to 15thNight
37%16%20%17%7%
805
16th to endNight
35%21%19%16%41
825
December1st to 15thNight
29%26%22%16%4
825
16th to endNight
30%22%23%15%5%1
880
Page generated at 2018-02-23 12:51:36. Version ac04

Copyright 2018 A. Danko


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