Jasper House Viewpoint
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Jasper House Viewpoint clear sky chart from 2005-11-05 to 2018-01-12.

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
27%
15588
9%
48295
4%
15557
32%
15557
14%
35425

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%
997
6%
3043
3%
992
20%
992
10%
2390
January16th to endNight
17%
778
13%
2721
5%
778
27%
778
11%
1932
February1st to 15thNight
20%
698
7%
2464
4%
696
26%
696
10%
1838
February16th to endNight
29%
632
10%
1977
7%
632
34%
632
15%
1444
March1st to 15thNight
15%
720
11%
2160
4%
720
23%
720
12%
1594
March16th to endNight
27%
768
10%
2016
3%
768
31%
768
15%
1526
April1st to 15thNight
30%
694
8%
1774
3%
694
34%
694
12%
1392
April16th to endNight
28%
444
7%
1524
5%
444
32%
444
10%
1170
May1st to 15thNight
40%
359
4%
1413
4%
359
42%
359
13%
1007
May16th to endNight
42%
374
1%
1288
0%
374
42%
374
13%
978
June1st to 15thNight
40%
360
0%
1080
0%
360
40%
360
11%
860
June16th to endNight
39%
360
0%
1080
0%
360
39%
360
15%
808
July1st to 15thNight
45%
340
0%
1020
0%
340
45%
340
19%
723
July16th to endNight
52%
376
3%
1268
1%
354
54%
354
19%
839
August1st to 15thNight
56%
360
4%
1432
6%
358
58%
358
15%
959
August16th to endNight
41%
524
13%
1670
12%
524
44%
524
19%
1121
September1st to 15thNight
44%
720
12%
1800
7%
720
45%
720
24%
1298
September16th to endNight
34%
716
15%
1959
6%
716
40%
716
21%
1336
October1st to 15thNight
29%
720
10%
2175
6%
720
34%
720
15%
1594
October16th to endNight
22%
768
11%
2496
5%
768
30%
768
11%
1826
November1st to 15thNight
16%
825
10%
2685
4%
825
22%
825
12%
1906
November16th to endNight
15%
975
9%
2925
1%
975
22%
975
11%
2202
December1st to 15thNight
20%
992
10%
2997
5%
992
25%
992
13%
2235
December16th to endNight
19%
1088
11%
3328
3%
1088
26%
1088
13%
2447

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
9%9%48%8%46%6%6%8%26%
49084
Night
5%7%48%7%46%6%7%9%32%
48436
TransparencyDay
55%11%15%12%4
48730
Night
48%11%17%15%5%
48295
SeeingDay
20%18%30%21%7%1
6911
Night
12%16%35%24%9%
15596

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
37%5%8%7%5%5%8%9%11%26%
1146
16th to endDay
18%48%7%47%7%7%10%32%
1506
February1st to 15thDay
19%38%8%5%6%7%7%10%30%
1400
16th to endDay
17%6%10%9%6%8%9%8%7%25%
1497
March1st to 15thDay
7%48%9%47%8%9%10%28%
1800
16th to endDay
29%6%12%8%5%7%8%8%11%19%
2208
April1st to 15thDay
314%7%11%9%6%7%6%7%8%17%
2173
16th to endDay
8%13%6%11%9%45%5%5%7%20%
2436
May1st to 15thDay
8%14%5%9%7%36%46%6%25%
2538
16th to endDay
22%12%5%7%6%35%446%20%
2820
June1st to 15thDay
23%11%38%8%46%45%6%16%
2880
16th to endDay
16%8%5%8%8%5%7%6%6%5%20%
2880
July1st to 15thDay
17%8%36%7%36%5%5%7%27%
2880
16th to endDay
11%6%37%9%5%7%6%6%7%26%
2807
August1st to 15thDay
13%7%38%7%47%5%6%8%27%
2520
16th to endDay
11%7%36%7%46%5%7%9%30%
2530
September1st to 15thDay
11%9%37%5%345%6%6%35%
2160
16th to endDay
10%6%36%5%35%5%6%7%37%
2001
October1st to 15thDay
5%12%38%8%45%6%7%7%29%
1782
16th to endDay
5%7%37%6%35%7%7%11%33%
1728
November1st to 15thDay
26%38%8%5%7%6%7%11%31%
1489
16th to endDay
27%47%8%35%6%8%12%33%
1365
December1st to 15thDay
26%49%9%47%7%6%8%31%
1290
16th to endDay
17%48%8%447%6%9%38%
1248
January1st to 15thNight
28%5%10%8%5%6%6%8%11%25%
3043
16th to endNight
17%49%6%5%6%6%7%11%33%
2721
February1st to 15thNight
37%49%9%46%8%7%9%29%
2452
16th to endNight
18%5%9%7%48%7%7%9%31%
1977
March1st to 15thNight
6%49%7%37%7%10%10%32%
2160
16th to endNight
28%5%11%6%36%7%7%10%28%
2012
April1st to 15thNight
311%7%8%6%45%6%7%8%28%
1774
16th to endNight
10%12%48%7%5%5%45%6%29%
1524
May1st to 15thNight
8%9%47%7%36%5%6%8%32%
1412
16th to endNight
19%10%345%35%45%6%30%
1288
June1st to 15thNight
16%9%46%5%45%6%7%8%25%
1080
16th to endNight
12%6%35%8%5%6%6%8%7%30%
1080
July1st to 15thNight
15%425%5%35%47%8%36%
1080
16th to endNight
8%4245%5%5%6%8%9%38%
1358
August1st to 15thNight
13%5%25%6%35%5%7%9%34%
1440
16th to endNight
9%425%5%36%6%7%9%38%
1670
September1st to 15thNight
11%7%15%5%345%47%41%
1800
16th to endNight
8%6%25%5%346%6%8%42%
1959
October1st to 15thNight
6%12%36%6%446%7%8%35%
2175
16th to endNight
46%38%8%46%6%8%10%33%
2496
November1st to 15thNight
28%48%5%46%7%8%9%33%
2685
16th to endNight
18%5%9%7%45%5%8%11%31%
2925
December1st to 15thNight
27%5%10%7%46%6%7%9%32%
2997
16th to endNight
16%5%9%9%5%7%7%8%10%29%
3328

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
52%13%17%10%41
1146
16th to endDay
48%12%15%13%7%2
1506
February1st to 15thDay
47%14%16%13%7%1
1400
16th to endDay
56%11%12%11%6%1
1497
March1st to 15thDay
48%13%17%15%4
1800
16th to endDay
58%13%15%8%2
2208
April1st to 15thDay
64%11%13%8%1
2173
16th to endDay
64%10%14%8%2
2436
May1st to 15thDay
59%9%13%10%6%
2538
16th to endDay
66%8%11%9%3
2825
June1st to 15thDay
70%9%9%8%2
2880
16th to endDay
63%11%12%9%3
2880
July1st to 15thDay
56%10%12%15%4
2711
16th to endDay
56%11%15%13%2
2634
August1st to 15thDay
53%13%16%11%4
2503
16th to endDay
49%12%15%17%4
2530
September1st to 15thDay
49%8%15%18%6%1
2160
16th to endDay
46%9%16%18%6%1
2001
October1st to 15thDay
53%10%16%15%3
1782
16th to endDay
46%13%19%18%2
1728
November1st to 15thDay
48%12%19%16%2
1489
16th to endDay
44%15%21%12%32
1365
December1st to 15thDay
53%11%12%16%5%
1290
16th to endDay
43%9%22%14%8%
1248
January1st to 15thNight
54%13%16%9%32
3043
16th to endNight
48%10%16%14%7%2
2721
February1st to 15thNight
51%12%15%12%5%1
2464
16th to endNight
49%10%14%17%5%1
1977
March1st to 15thNight
46%13%18%15%4
2160
16th to endNight
49%11%18%16%3
2016
April1st to 15thNight
53%11%16%13%4
1774
16th to endNight
54%12%16%13%2
1524
May1st to 15thNight
49%11%18%13%6%
1413
16th to endNight
54%10%15%14%4
1288
June1st to 15thNight
57%12%15%10%3
1080
16th to endNight
50%12%18%13%5%
1080
July1st to 15thNight
45%10%18%20%5%
1020
16th to endNight
41%11%24%18%3
1268
August1st to 15thNight
44%12%23%16%3
1432
16th to endNight
39%13%20%20%6%
1670
September1st to 15thNight
43%9%16%20%8%1
1800
16th to endNight
39%10%20%20%8%
1959
October1st to 15thNight
47%12%16%18%5%
2175
16th to endNight
47%13%18%16%3
2496
November1st to 15thNight
46%10%20%16%4
2685
16th to endNight
49%13%16%13%41
2925
December1st to 15thNight
51%10%16%16%5%
2997
16th to endNight
49%11%17%14%6%1
3328

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%330%43%9%6%
82
16th to endDay
7%20%32%28%9%1
64
February1st to 15thDay
16%21%48%6%6%
60
16th to endDay
9%24%37%21%6%
215
March1st to 15thDay
15%35%34%11%2
270
16th to endDay
15%25%39%16%2
288
April1st to 15thDay
25%22%33%15%1
269
16th to endDay
23%25%29%15%5%
270
May1st to 15thDay
20%19%31%20%6%
315
16th to endDay
26%11%22%24%13%2
535
June1st to 15thDay
25%15%27%21%9%
675
16th to endDay
21%15%30%21%9%1
675
July1st to 15thDay
21%13%31%22%10%
645
16th to endDay
18%16%32%22%8%1
475
August1st to 15thDay
17%10%27%31%9%3
315
16th to endDay
19%21%36%18%4
332
September1st to 15thDay
24%20%29%21%3
315
16th to endDay
23%24%26%17%6%
315
October1st to 15thDay
22%24%27%16%6%2
276
16th to endDay
16%22%25%26%6%2
144
November1st to 15thDay
20%19%33%19%7%2
100
16th to endDay
12%24%31%22%45%
90
December1st to 15thDay
421%25%26%16%5%
90
16th to endDay
117%46%17%13%3
96
January1st to 15thNight
12%18%45%17%41
997
16th to endNight
10%29%37%16%6%
778
February1st to 15thNight
9%22%37%23%7%
704
16th to endNight
7%12%41%27%10%
632
March1st to 15thNight
6%24%44%19%4
720
16th to endNight
9%15%35%30%8%
768
April1st to 15thNight
10%15%33%30%9%
694
16th to endNight
18%13%32%25%10%
444
May1st to 15thNight
14%8%28%34%13%
360
16th to endNight
24%6%21%26%19%1
375
June1st to 15thNight
22%5%23%30%16%
360
16th to endNight
15%8%27%30%16%1
360
July1st to 15thNight
18%5%25%32%17%
340
16th to endNight
9%5%25%33%25%
376
August1st to 15thNight
17%316%28%32%2
360
16th to endNight
14%8%29%33%11%
524
September1st to 15thNight
17%9%23%29%18%1
720
16th to endNight
16%15%28%25%12%1
716
October1st to 15thNight
15%15%34%25%7%
720
16th to endNight
12%22%37%21%6%
768
November1st to 15thNight
12%26%39%16%4
825
16th to endNight
11%23%42%17%31
975
December1st to 15thNight
10%19%41%22%5%
992
16th to endNight
7%19%44%20%7%
1088
Page generated at 2018-01-12 20:01:28. Version ac04

Copyright 2018 A. Danko


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