Jasper Maligne Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jasper Maligne Lake clear sky chart from 2005-11-05 to

2017-09-12
.

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
26%
15008
6%
46589
4%
14976
28%
14976
12%
36576

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
14%
928
5%
2853
3%
923
16%
923
7%
2459
January16th to endNight
16%
768
10%
2688
6%
768
22%
768
8%
2177
February1st to 15thNight
18%
700
5%
2464
4%
697
21%
697
8%
2032
February16th to endNight
29%
632
10%
1964
8%
632
34%
632
14%
1508
March1st to 15thNight
12%
720
7%
2160
4%
720
17%
720
9%
1785
March16th to endNight
23%
768
6%
2019
2%
768
25%
768
11%
1664
April1st to 15thNight
28%
690
6%
1770
3%
690
29%
690
12%
1442
April16th to endNight
31%
461
6%
1541
6%
461
33%
461
11%
1219
May1st to 15thNight
43%
359
5%
1416
5%
359
44%
359
12%
1028
May16th to endNight
42%
374
1%
1309
0%
374
42%
374
13%
982
June1st to 15thNight
35%
360
0%
1096
0%
360
35%
360
13%
859
June16th to endNight
40%
360
0%
1080
0%
360
40%
360
15%
806
July1st to 15thNight
44%
340
0%
1020
0%
340
44%
340
22%
693
July16th to endNight
52%
376
3%
1306
2%
354
53%
354
19%
850
August1st to 15thNight
56%
360
5%
1432
8%
358
56%
358
18%
919
August16th to endNight
42%
533
13%
1679
13%
533
44%
533
24%
1109
September1st to 15thNight
44%
706
12%
1765
7%
706
45%
706
27%
1248
September16th to endNight
33%
656
12%
1804
6%
656
38%
656
20%
1288
October1st to 15thNight
26%
660
8%
1986
5%
660
29%
660
13%
1543
October16th to endNight
16%
704
6%
2288
5%
704
19%
704
9%
1842
November1st to 15thNight
12%
758
4%
2456
2%
758
15%
758
7%
2087
November16th to endNight
13%
900
6%
2700
2%
900
16%
900
9%
2220
December1st to 15thNight
15%
903
8%
2721
5%
903
17%
903
9%
2275
December16th to endNight
18%
992
6%
3072
3%
992
20%
992
9%
2541

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
11%14%6%11%8%45%5%5%6%19%
48110
Night
6%12%6%11%9%46%6%6%7%22%
46731
TransparencyDay
64%7%12%11%3
47758
Night
59%8%14%12%4
46589
SeeingDay
21%17%30%21%8%1
6507
Night
12%13%38%23%10%1
15014

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
412%8%15%11%6%7%5%5%7%15%
1096
16th to endDay
415%8%11%12%36%45%7%19%
1536
February1st to 15thDay
313%8%14%9%46%6%6%6%18%
1400
16th to endDay
19%8%17%12%7%7%5%6%5%18%
1507
March1st to 15thDay
115%8%13%10%5%7%7%7%7%16%
1800
16th to endDay
317%11%16%10%47%5%5%5%11%
2204
April1st to 15thDay
6%19%12%15%9%5%5%5%4412%
2177
16th to endDay
8%23%8%13%8%34445%15%
2418
May1st to 15thDay
9%20%7%11%6%245%5%5%19%
2535
16th to endDay
17%17%5%9%8%4435%5%17%
2802
June1st to 15thDay
24%14%5%10%7%45%45%413%
2862
16th to endDay
19%12%7%11%9%45%445%15%
2880
July1st to 15thDay
16%10%5%8%7%35%5%5%6%23%
2880
16th to endDay
16%9%49%8%46%5%5%5%24%
2769
August1st to 15thDay
16%9%48%8%5%6%5%5%6%23%
2520
16th to endDay
16%10%48%6%45%45%6%26%
2521
September1st to 15thDay
15%13%37%6%235%4432%
2114
16th to endDay
14%14%37%6%34447%29%
1826
October1st to 15thDay
9%16%5%10%8%46%5%7%5%20%
1642
16th to endDay
6%16%6%11%8%47%45%7%21%
1584
November1st to 15thDay
313%7%11%11%6%8%6%6%7%17%
1389
16th to endDay
312%7%12%9%5%6%6%6%8%20%
1260
December1st to 15thDay
414%9%15%10%5%6%445%19%
1236
16th to endDay
112%7%16%9%5%6%6%6%7%20%
1152
January1st to 15thNight
414%9%16%12%5%6%5%6%5%12%
2853
16th to endNight
213%7%13%11%6%7%6%5%5%17%
2688
February1st to 15thNight
5%16%9%14%10%45%6%5%6%17%
2452
16th to endNight
110%6%12%10%5%7%7%6%6%22%
1964
March1st to 15thNight
213%7%12%12%5%8%7%6%6%18%
2160
16th to endNight
112%7%16%9%5%7%6%8%7%17%
2015
April1st to 15thNight
312%9%12%10%48%5%6%7%19%
1770
16th to endNight
6%18%5%9%6%45%6%6%7%22%
1541
May1st to 15thNight
7%16%48%6%25%6%7%7%27%
1415
16th to endNight
14%12%46%6%35%45%8%27%
1309
June1st to 15thNight
17%11%47%7%45%5%6%8%20%
1096
16th to endNight
12%7%47%7%36%7%7%7%27%
1080
July1st to 15thNight
14%6%26%326%46%6%38%
1080
16th to endNight
9%5%37%7%35%6%6%8%36%
1397
August1st to 15thNight
12%5%36%5%35%6%6%8%36%
1440
16th to endNight
13%6%25%435%5%6%9%37%
1679
September1st to 15thNight
13%8%36%5%34446%39%
1765
16th to endNight
11%8%26%5%35%5%6%8%35%
1804
October1st to 15thNight
6%14%5%10%7%36%6%6%8%24%
1986
16th to endNight
7%15%7%13%8%45%5%5%7%19%
2288
November1st to 15thNight
412%7%13%11%5%8%6%7%7%15%
2456
16th to endNight
313%8%13%11%5%7%5%5%7%18%
2700
December1st to 15thNight
413%9%14%10%5%6%5%46%17%
2721
16th to endNight
111%8%14%11%5%7%7%8%9%13%
3072

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%8%10%7%31
1096
16th to endDay
64%7%9%8%7%2
1536
February1st to 15thDay
65%7%10%10%5%1
1400
16th to endDay
66%6%10%10%41
1507
March1st to 15thDay
67%8%10%9%2
1800
16th to endDay
72%8%10%6%1
2204
April1st to 15thDay
75%6%8%7%
2177
16th to endDay
71%8%11%6%1
2418
May1st to 15thDay
65%6%13%9%4
2535
16th to endDay
67%6%14%8%3
2807
June1st to 15thDay
69%7%11%8%1
2862
16th to endDay
68%6%13%9%2
2880
July1st to 15thDay
58%7%14%14%4
2711
16th to endDay
60%6%16%13%3
2598
August1st to 15thDay
59%7%15%13%3
2503
16th to endDay
56%6%13%18%4
2521
September1st to 15thDay
53%5%14%18%6%1
2114
16th to endDay
54%7%15%15%6%
1826
October1st to 15thDay
62%8%12%14%2
1642
16th to endDay
62%8%14%12%1
1584
November1st to 15thDay
66%9%12%8%1
1389
16th to endDay
60%10%14%7%42
1260
December1st to 15thDay
68%7%6%12%4
1236
16th to endDay
62%8%13%9%41
1152
January1st to 15thNight
71%7%10%5%31
2853
16th to endNight
66%7%8%9%5%2
2688
February1st to 15thNight
67%7%10%7%5%2
2464
16th to endNight
58%7%11%15%5%1
1964
March1st to 15thNight
66%7%12%10%3
2160
16th to endNight
62%9%16%9%2
2019
April1st to 15thNight
62%8%14%11%2
1770
16th to endNight
61%8%15%11%2
1541
May1st to 15thNight
54%8%16%13%6%
1416
16th to endNight
54%10%16%13%4
1309
June1st to 15thNight
59%8%19%10%2
1096
16th to endNight
53%9%21%13%2
1080
July1st to 15thNight
45%7%21%20%5%
1020
16th to endNight
43%8%22%20%4
1306
August1st to 15thNight
41%10%25%18%3
1432
16th to endNight
41%8%22%21%6%
1679
September1st to 15thNight
45%5%19%20%7%
1765
16th to endNight
45%9%18%18%7%
1804
October1st to 15thNight
55%10%14%15%3
1986
16th to endNight
63%8%14%11%1
2288
November1st to 15thNight
68%8%10%7%3
2456
16th to endNight
63%10%10%8%42
2700
December1st to 15thNight
68%6%8%9%6%
2721
16th to endNight
64%10%11%8%41
3072

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
6%5%36%36%11%3
60
16th to endDay
7%14%46%21%44
64
February1st to 15thDay
11%23%45%16%3
60
16th to endDay
8%18%42%22%8%
215
March1st to 15thDay
16%36%31%12%3
270
16th to endDay
14%23%44%15%1
288
April1st to 15thDay
20%22%31%20%4
269
16th to endDay
22%23%27%17%7%1
270
May1st to 15thDay
23%16%30%20%8%1
312
16th to endDay
22%9%22%25%16%3
517
June1st to 15thDay
27%11%27%20%10%1
657
16th to endDay
21%15%29%22%10%1
675
July1st to 15thDay
22%11%27%27%9%1
645
16th to endDay
24%14%29%23%7%
437
August1st to 15thDay
20%11%27%26%11%2
315
16th to endDay
25%18%35%16%3
332
September1st to 15thDay
31%19%23%19%5%1
300
16th to endDay
28%26%25%16%3
255
October1st to 15thDay
18%23%35%17%4
217
16th to endDay
13%14%35%26%6%4
96
November1st to 15thDay
20%27%36%11%21
69
16th to endDay
6%11%41%20%8%11%
60
December1st to 15thDay
10%26%28%13%15%6%
60
16th to endDay
117%42%21%14%3
64
January1st to 15thNight
11%17%48%16%5%
928
16th to endNight
11%18%44%16%7%1
768
February1st to 15thNight
13%15%41%20%7%
704
16th to endNight
6%10%43%28%9%1
632
March1st to 15thNight
8%18%49%16%5%
720
16th to endNight
6%13%40%30%8%
768
April1st to 15thNight
6%14%35%29%12%
690
16th to endNight
16%11%31%30%9%
461
May1st to 15thNight
13%7%24%36%16%1
360
16th to endNight
18%6%23%26%21%2
375
June1st to 15thNight
20%6%26%28%17%1
360
16th to endNight
16%9%25%30%17%
360
July1st to 15thNight
19%5%23%32%18%
340
16th to endNight
12%5%21%40%20%
376
August1st to 15thNight
15%315%36%28%1
360
16th to endNight
16%9%25%36%11%1
533
September1st to 15thNight
18%7%25%28%17%2
706
16th to endNight
17%13%30%24%10%2
656
October1st to 15thNight
13%13%38%26%7%
660
16th to endNight
14%14%44%19%5%
704
November1st to 15thNight
13%20%49%13%3
758
16th to endNight
11%16%49%15%41
900
December1st to 15thNight
12%18%45%16%6%
903
16th to endNight
6%15%49%19%8%
992
Page generated at 2017-09-13 05:39:04. Version ac04

Copyright 2017 A. Danko


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