Jasper Athabasca Glacier
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jasper Athabasca Glacier clear sky chart from 2005-11-05 to 2017-09-10.

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
24%
15002
6%
46532
4%
14971
26%
14971
10%
36849

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
18%
911
6%
2781
4%
906
19%
906
7%
2382
January16th to endNight
20%
768
9%
2688
7%
768
23%
768
8%
2134
February1st to 15thNight
22%
702
5%
2464
4%
700
24%
700
7%
1980
February16th to endNight
28%
632
8%
1951
6%
632
31%
632
12%
1531
March1st to 15thNight
12%
720
5%
2160
3%
720
15%
720
8%
1817
March16th to endNight
16%
768
2%
2022
1%
768
16%
768
7%
1757
April1st to 15thNight
20%
686
5%
1766
2%
686
22%
686
10%
1480
April16th to endNight
25%
481
5%
1561
4%
481
28%
481
8%
1270
May1st to 15thNight
36%
359
5%
1419
4%
359
38%
359
10%
1012
May16th to endNight
31%
374
2%
1309
0%
374
31%
374
10%
990
June1st to 15thNight
29%
360
0%
1147
0%
360
29%
360
9%
929
June16th to endNight
29%
360
0%
1080
0%
360
29%
360
14%
821
July1st to 15thNight
46%
340
0%
1034
0%
340
46%
340
20%
708
July16th to endNight
46%
376
4%
1341
3%
354
50%
354
18%
855
August1st to 15thNight
56%
360
7%
1432
12%
358
57%
358
18%
888
August16th to endNight
41%
544
14%
1690
13%
544
44%
544
21%
1108
September1st to 15thNight
41%
700
12%
1750
7%
700
42%
700
22%
1240
September16th to endNight
33%
656
11%
1812
6%
656
36%
656
18%
1325
October1st to 15thNight
23%
660
8%
1980
6%
660
26%
660
12%
1538
October16th to endNight
17%
704
5%
2288
3%
704
20%
704
7%
1875
November1st to 15thNight
11%
757
5%
2433
2%
757
14%
757
5%
2116
November16th to endNight
14%
900
5%
2700
3%
900
16%
900
7%
2266
December1st to 15thNight
18%
900
8%
2700
5%
900
21%
900
8%
2243
December16th to endNight
15%
984
4%
3024
2%
984
17%
984
6%
2584

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
7%15%8%13%9%46%5%5%5%18%
48131
Night
5%13%9%16%11%5%6%45%5%17%
46677
TransparencyDay
61%10%11%11%3
47781
Night
57%11%12%11%41
46532
SeeingDay
14%23%27%21%11%2
6392
Night
6%24%30%22%12%2
15006

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
213%11%22%10%6%6%43313%
1167
16th to endDay
111%8%17%15%5%8%7%5%413%
1536
February1st to 15thDay
212%10%20%12%46%6%5%5%13%
1400
16th to endDay
19%9%17%16%6%9%7%5%411%
1520
March1st to 15thDay
17%13%19%15%5%6%6%328%
1800
16th to endDay
116%12%22%12%6%8%5%336%
2202
April1st to 15thDay
417%12%18%12%5%6%5%447%
2181
16th to endDay
420%9%16%10%5%6%5%35%11%
2397
May1st to 15thDay
8%21%7%9%7%36%45%5%19%
2530
16th to endDay
14%19%7%9%6%36%45%5%16%
2802
June1st to 15thDay
18%17%6%9%7%35%5%5%6%14%
2811
16th to endDay
14%16%7%10%7%45%45%6%18%
2880
July1st to 15thDay
11%9%37%7%36%6%6%8%28%
2862
16th to endDay
8%9%47%7%46%6%7%8%29%
2734
August1st to 15thDay
10%9%38%6%35%6%7%9%28%
2520
16th to endDay
11%10%47%7%46%5%6%7%27%
2510
September1st to 15thDay
8%14%48%7%45%446%31%
2097
16th to endDay
13%18%5%7%6%3445%6%24%
1818
October1st to 15thDay
8%17%8%11%8%47%5%5%6%16%
1650
16th to endDay
7%20%8%16%10%5%4435%13%
1584
November1st to 15thDay
420%12%19%13%5%5%4328%
1413
16th to endDay
113%10%20%13%5%6%5%3316%
1260
December1st to 15thDay
213%11%19%14%45%33417%
1260
16th to endDay
10%11%20%17%7%7%44311%
1197
January1st to 15thNight
113%10%22%13%45%45%411%
2781
16th to endNight
8%9%20%14%6%7%5%6%6%14%
2688
February1st to 15thNight
211%8%19%14%6%6%5%5%5%14%
2452
16th to endNight
8%10%17%13%6%7%6%5%6%16%
1951
March1st to 15thNight
111%12%25%15%5%6%5%439%
2160
16th to endNight
216%13%22%15%45%4337%
2018
April1st to 15thNight
214%12%19%11%46%5%5%5%12%
1766
16th to endNight
5%19%7%12%9%6%45%5%7%15%
1561
May1st to 15thNight
7%19%49%6%46%5%6%6%23%
1418
16th to endNight
13%19%38%6%36%5%5%7%19%
1309
June1st to 15thNight
18%20%5%8%5%25%46%7%14%
1147
16th to endNight
17%15%5%10%7%25%45%6%18%
1080
July1st to 15thNight
10%10%47%6%36%5%8%7%30%
1095
16th to endNight
11%9%46%7%46%5%6%6%33%
1434
August1st to 15thNight
8%7%26%5%35%6%8%9%34%
1440
16th to endNight
10%10%36%6%35%5%7%9%31%
1690
September1st to 15thNight
10%15%5%7%424346%34%
1750
16th to endNight
12%14%6%8%5%35%35%6%28%
1812
October1st to 15thNight
7%17%6%11%9%45%46%7%19%
1980
16th to endNight
5%20%11%16%10%44446%10%
2288
November1st to 15thNight
417%14%20%13%5%43239%
2433
16th to endNight
112%10%20%15%5%7%43413%
2700
December1st to 15thNight
111%11%20%13%6%6%43315%
2700
16th to endNight
7%10%23%18%7%8%5%439%
3024

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
63%11%11%7%32
1167
16th to endDay
58%14%10%8%5%2
1536
February1st to 15thDay
60%9%11%9%6%1
1400
16th to endDay
64%12%6%10%42
1520
March1st to 15thDay
67%12%8%7%2
1800
16th to endDay
77%7%8%5%
2202
April1st to 15thDay
76%7%8%6%
2181
16th to endDay
72%9%10%5%1
2397
May1st to 15thDay
64%9%11%10%3
2530
16th to endDay
65%8%12%10%2
2807
June1st to 15thDay
66%7%12%10%2
2811
16th to endDay
60%9%12%14%2
2880
July1st to 15thDay
47%11%14%19%5%
2694
16th to endDay
47%11%16%19%5%
2564
August1st to 15thDay
52%12%15%15%4
2503
16th to endDay
50%11%12%20%5%
2510
September1st to 15thDay
50%8%14%19%6%1
2097
16th to endDay
53%9%12%16%6%
1818
October1st to 15thDay
60%12%9%13%3
1650
16th to endDay
61%10%14%11%1
1584
November1st to 15thDay
65%14%8%7%2
1413
16th to endDay
62%12%11%6%43
1260
December1st to 15thDay
60%13%8%9%5%1
1260
16th to endDay
60%13%12%6%42
1197
January1st to 15thNight
64%13%8%5%42
2781
16th to endNight
56%14%11%8%6%3
2688
February1st to 15thNight
58%13%12%7%43
2464
16th to endNight
57%9%12%12%6%2
1951
March1st to 15thNight
63%11%11%9%3
2160
16th to endNight
67%11%11%7%1
2022
April1st to 15thNight
61%12%12%10%2
1766
16th to endNight
60%11%13%9%3
1561
May1st to 15thNight
48%12%16%16%5%
1419
16th to endNight
58%7%14%14%4
1309
June1st to 15thNight
64%8%12%12%2
1147
16th to endNight
52%10%16%17%2
1080
July1st to 15thNight
41%11%17%21%7%
1034
16th to endNight
38%12%19%23%6%
1341
August1st to 15thNight
37%12%22%24%3
1432
16th to endNight
37%11%18%24%6%
1690
September1st to 15thNight
42%10%15%23%7%1
1750
16th to endNight
46%11%16%16%8%
1812
October1st to 15thNight
55%10%14%13%5%
1980
16th to endNight
62%11%12%10%2
2288
November1st to 15thNight
70%10%7%6%31
2433
16th to endNight
64%10%9%7%42
2700
December1st to 15thNight
62%11%8%8%8%
2700
16th to endNight
64%13%9%6%31
3024

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
1135%36%16%8%
60
16th to endDay
6%15%45%15%7%9%
64
February1st to 15thDay
328%41%18%5%3
60
16th to endDay
326%36%23%9%
215
March1st to 15thDay
8%44%31%12%2
270
16th to endDay
9%31%36%18%3
288
April1st to 15thDay
10%34%29%19%4
269
16th to endDay
16%30%25%17%8%1
270
May1st to 15thDay
15%22%28%18%12%2
307
16th to endDay
20%16%15%20%19%7%
517
June1st to 15thDay
20%18%20%20%16%2
606
16th to endDay
15%19%23%24%13%3
675
July1st to 15thDay
14%16%23%26%15%3
628
16th to endDay
13%19%31%22%10%2
403
August1st to 15thDay
13%15%26%26%13%4
315
16th to endDay
15%21%36%19%6%
332
September1st to 15thDay
21%29%23%17%5%1
294
16th to endDay
16%36%26%15%4
255
October1st to 15thDay
13%31%31%18%4
211
16th to endDay
12%10%32%29%12%3
96
November1st to 15thDay
9%24%47%9%5%2
73
16th to endDay
318%40%15%11%11%
60
December1st to 15thDay
5%25%25%16%15%13%
60
16th to endDay
20%31%28%18%1
64
January1st to 15thNight
331%37%19%6%1
911
16th to endNight
234%30%20%8%2
768
February1st to 15thNight
229%33%19%11%4
704
16th to endNight
121%35%26%12%3
632
March1st to 15thNight
230%41%17%6%1
720
16th to endNight
323%32%26%11%2
768
April1st to 15thNight
424%29%26%13%1
686
16th to endNight
7%24%29%26%11%1
481
May1st to 15thNight
8%21%18%30%19%1
360
16th to endNight
18%20%18%20%17%4
375
June1st to 15thNight
19%20%16%22%18%4
360
16th to endNight
15%18%20%22%18%4
360
July1st to 15thNight
14%13%16%24%26%5%
340
16th to endNight
10%18%14%30%23%2
376
August1st to 15thNight
10%12%8%30%30%7%
360
16th to endNight
11%13%23%33%14%2
544
September1st to 15thNight
14%13%21%26%19%5%
700
16th to endNight
11%19%27%22%14%4
656
October1st to 15thNight
10%19%34%23%10%2
660
16th to endNight
7%21%40%20%8%1
704
November1st to 15thNight
6%33%39%13%5%1
757
16th to endNight
331%38%19%42
900
December1st to 15thNight
331%34%19%9%1
900
16th to endNight
129%35%20%10%2
984
Page generated at 2017-09-11 17:35:31. Version ac04

Copyright 2017 A. Danko


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