Nakusp
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Nakusp clear sky chart from 2005-11-05 to 2018-03-11.

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
28%
15673
6%
49024
5%
15642
30%
15642
12%
38432

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
12%
859
2%
2796
1%
856
13%
856
4%
2516
January16th to endNight
11%
832
2%
2912
1%
832
12%
832
4%
2641
February1st to 15thNight
15%
762
3%
2645
2%
758
17%
758
5%
2330
February16th to endNight
20%
684
5%
2086
4%
684
22%
684
9%
1742
March1st to 15thNight
19%
764
3%
2292
2%
764
20%
764
7%
1966
March16th to endNight
21%
768
6%
2018
1%
768
23%
768
11%
1682
April1st to 15thNight
32%
719
6%
1799
2%
719
33%
719
15%
1444
April16th to endNight
32%
504
8%
1584
6%
504
35%
504
15%
1168
May1st to 15thNight
42%
359
9%
1440
11%
359
47%
359
18%
928
May16th to endNight
44%
374
6%
1377
6%
374
45%
374
15%
958
June1st to 15thNight
39%
360
2%
1260
0%
360
39%
360
16%
910
June16th to endNight
42%
360
4%
1124
0%
360
42%
360
20%
789
July1st to 15thNight
61%
340
6%
1197
2%
340
62%
340
31%
669
July16th to endNight
64%
376
13%
1416
18%
354
69%
354
36%
677
August1st to 15thNight
74%
360
20%
1432
28%
358
78%
358
35%
699
August16th to endNight
61%
604
23%
1750
20%
604
63%
604
41%
965
September1st to 15thNight
57%
720
18%
1800
11%
720
59%
720
40%
1109
September16th to endNight
46%
716
16%
1971
11%
716
49%
716
27%
1325
October1st to 15thNight
35%
720
9%
2137
7%
720
37%
720
18%
1553
October16th to endNight
26%
768
6%
2496
5%
768
28%
768
12%
1957
November1st to 15thNight
10%
760
3%
2548
2%
760
12%
760
5%
2240
November16th to endNight
11%
949
2%
2899
0%
949
13%
949
5%
2616
December1st to 15thNight
14%
975
3%
2925
1%
975
15%
975
6%
2617
December16th to endNight
6%
1040
1%
3120
0%
1040
7%
1040
3%
2931

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
13%11%48%7%45%5%5%6%25%
49619
Night
13%14%5%9%7%45%45%5%23%
49183
Cloud CoverDay
15%12%47%6%35%5%5%6%25%
49619
Night
15%15%5%7%6%35%45%6%24%
49187
TransparencyDay
58%8%13%13%5%
49282
Night
60%7%12%13%5%
49024
SeeingDay
19%16%29%24%8%
6476
Night
23%9%30%26%9%
15679

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
20%19%7%12%8%5%5%5%347%
1482
16th to endDay
13%20%7%12%11%5%445%5%9%
1664
February1st to 15thDay
14%16%5%12%9%45%45%5%14%
1549
16th to endDay
7%15%7%11%11%46%6%6%5%17%
1674
March1st to 15thDay
12%16%7%9%9%5%7%5%5%6%13%
1904
16th to endDay
13%16%7%10%8%5%6%5%5%6%13%
2205
April1st to 15thDay
12%13%6%10%8%5%7%5%6%7%17%
2149
16th to endDay
13%14%5%9%9%46%5%5%6%21%
2375
May1st to 15thDay
13%9%37%7%35%45%7%31%
2511
16th to endDay
15%9%49%8%36%5%5%6%23%
2734
June1st to 15thDay
22%9%47%7%46%446%21%
2700
16th to endDay
15%6%37%7%47%6%5%7%27%
2829
July1st to 15thDay
6%325%6%36%5%7%7%44%
2683
16th to endDay
6%3145%35%5%6%9%47%
2657
August1st to 15thDay
4315%5%445%7%8%49%
2520
16th to endDay
7%4245%345%6%9%46%
2450
September1st to 15thDay
8%5%26%5%35%446%45%
2160
16th to endDay
14%9%27%6%345%5%8%31%
1989
October1st to 15thDay
15%10%5%8%6%35%5%6%5%25%
1821
16th to endDay
23%11%5%9%7%34445%19%
1728
November1st to 15thDay
22%15%6%10%9%5%6%43410%
1639
16th to endDay
16%18%7%10%11%46%445%11%
1375
December1st to 15thDay
13%19%8%10%10%5%6%5%5%49%
1365
16th to endDay
12%21%7%13%8%6%7%6%436%
1456
January1st to 15thNight
21%24%8%11%7%5%5%4325%
2796
16th to endNight
15%20%9%16%10%45%4334
2912
February1st to 15thNight
16%22%6%13%8%35%4449%
2633
16th to endNight
8%19%8%11%10%5%6%5%5%6%11%
2086
March1st to 15thNight
12%18%7%11%9%45%45%6%13%
2292
16th to endNight
13%15%410%7%36%5%6%6%19%
2014
April1st to 15thNight
10%13%5%8%7%36%6%6%6%25%
1799
16th to endNight
12%10%48%7%345%6%8%29%
1584
May1st to 15thNight
9%8%26%5%46%5%5%8%38%
1439
16th to endNight
13%7%36%5%35%5%5%9%33%
1377
June1st to 15thNight
17%8%25%5%36%5%6%7%30%
1260
16th to endNight
10%6%35%6%46%6%5%9%35%
1124
July1st to 15thNight
4325%43445%7%52%
1269
16th to endNight
5%21333447%8%57%
1512
August1st to 15thNight
422441346%7%58%
1440
16th to endNight
431342336%6%59%
1750
September1st to 15thNight
7%4134245%5%6%54%
1800
16th to endNight
11%7%26%5%2445%7%43%
1971
October1st to 15thNight
12%8%38%6%35%5%6%6%33%
2137
16th to endNight
20%11%47%7%35%6%7%6%20%
2496
November1st to 15thNight
22%18%5%11%9%45%44410%
2548
16th to endNight
18%20%8%12%10%45%4338%
2899
December1st to 15thNight
14%21%7%14%9%5%5%3339%
2925
16th to endNight
13%23%8%16%10%5%6%4233
3120

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
23%19%7%11%6%25%35%310%
1482
16th to endDay
17%20%7%10%7%25%5%5%5%10%
1664
February1st to 15thDay
18%17%8%9%8%45%34415%
1549
16th to endDay
9%16%7%11%9%45%6%6%5%17%
1674
March1st to 15thDay
17%18%6%9%8%46%5%5%5%13%
1904
16th to endDay
15%19%6%9%8%35%46%6%13%
2205
April1st to 15thDay
13%16%6%8%8%47%5%5%6%17%
2149
16th to endDay
13%16%5%8%8%46%447%19%
2375
May1st to 15thDay
14%11%36%5%35%5%6%6%30%
2511
16th to endDay
15%11%48%8%45%5%5%7%22%
2734
June1st to 15thDay
24%10%48%7%45%446%20%
2700
16th to endDay
17%7%36%7%46%6%5%7%26%
2829
July1st to 15thDay
7%425%5%36%6%7%8%43%
2683
16th to endDay
7%313435%5%6%9%48%
2657
August1st to 15thDay
5%4145%345%7%8%49%
2520
16th to endDay
8%4244345%6%8%45%
2450
September1st to 15thDay
10%6%26%435%447%45%
2160
16th to endDay
15%8%37%5%3445%8%32%
1989
October1st to 15thDay
17%10%47%6%46%5%5%5%26%
1821
16th to endDay
26%12%36%5%35%5%45%20%
1728
November1st to 15thDay
26%16%5%9%7%4444411%
1639
16th to endDay
20%19%5%8%7%35%6%45%13%
1375
December1st to 15thDay
15%18%7%11%9%5%5%445%11%
1365
16th to endDay
13%24%7%11%8%6%5%445%7%
1456
January1st to 15thNight
25%23%6%8%6%344447%
2796
16th to endNight
17%21%8%11%7%47%6%437%
2912
February1st to 15thNight
19%21%6%11%7%34345%11%
2633
16th to endNight
10%21%8%9%6%36%5%6%7%14%
2086
March1st to 15thNight
16%19%6%9%6%345%5%5%15%
2292
16th to endNight
15%16%5%9%6%35%6%5%6%19%
2018
April1st to 15thNight
12%15%47%7%35%5%6%7%25%
1799
16th to endNight
14%10%46%6%25%46%8%29%
1584
May1st to 15thNight
9%8%35%6%46%5%6%8%37%
1439
16th to endNight
14%8%35%5%35%5%6%8%33%
1377
June1st to 15thNight
19%8%25%4346%5%6%32%
1260
16th to endNight
13%6%25%7%35%6%5%9%34%
1124
July1st to 15thNight
6%4135%35%46%6%52%
1269
16th to endNight
5%21232436%8%58%
1512
August1st to 15thNight
5%3123226%6%7%57%
1440
16th to endNight
6%31432435%7%57%
1750
September1st to 15thNight
9%41332346%6%54%
1800
16th to endNight
14%6%345%2445%8%42%
1971
October1st to 15thNight
15%9%37%5%245%5%7%33%
2137
16th to endNight
23%11%36%5%35%5%5%7%22%
2496
November1st to 15thNight
25%19%5%8%7%34445%12%
2548
16th to endNight
21%21%6%10%6%47%5%347%
2899
December1st to 15thNight
15%23%8%11%8%44445%9%
2925
16th to endNight
14%25%10%12%8%5%6%4444
3120

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
76%6%9%5%1
1482
16th to endDay
73%6%10%6%2
1664
February1st to 15thDay
71%7%10%7%2
1549
16th to endDay
67%8%13%7%2
1674
March1st to 15thDay
73%8%11%5%
1904
16th to endDay
72%8%13%4
2205
April1st to 15thDay
68%7%14%7%1
2149
16th to endDay
65%8%14%9%1
2375
May1st to 15thDay
53%7%16%18%4
2511
16th to endDay
61%8%15%12%1
2738
June1st to 15thDay
66%7%9%11%3
2700
16th to endDay
56%8%11%15%6%
2829
July1st to 15thDay
38%8%16%18%13%3
2526
16th to endDay
33%7%17%23%16%1
2490
August1st to 15thDay
32%9%17%26%11%2
2503
16th to endDay
35%8%16%26%11%1
2450
September1st to 15thDay
39%6%15%26%11%
2160
16th to endDay
50%7%15%19%6%
1989
October1st to 15thDay
58%8%14%16%2
1821
16th to endDay
64%8%14%11%
1728
November1st to 15thDay
77%8%8%41
1639
16th to endDay
70%10%10%6%1
1375
December1st to 15thDay
74%7%9%7%1
1365
16th to endDay
79%8%8%3
1456
January1st to 15thNight
80%5%7%42
2796
16th to endNight
79%7%7%32
2912
February1st to 15thNight
75%7%7%5%3
2645
16th to endNight
66%8%12%9%2
2086
March1st to 15thNight
70%7%12%7%1
2292
16th to endNight
65%8%13%9%2
2018
April1st to 15thNight
57%9%18%10%3
1799
16th to endNight
52%9%20%14%3
1584
May1st to 15thNight
46%5%19%18%9%
1440
16th to endNight
49%9%19%19%2
1377
June1st to 15thNight
51%8%12%18%7%
1260
16th to endNight
46%9%14%21%7%
1124
July1st to 15thNight
32%5%16%25%15%3
1197
16th to endNight
23%6%18%27%22%1
1416
August1st to 15thNight
24%6%16%34%15%3
1432
16th to endNight
25%6%16%34%15%1
1750
September1st to 15thNight
30%6%15%30%15%2
1800
16th to endNight
41%7%18%22%8%1
1971
October1st to 15thNight
50%8%16%18%5%
2137
16th to endNight
60%8%16%13%1
2496
November1st to 15thNight
75%7%8%5%2
2548
16th to endNight
78%7%7%5%1
2899
December1st to 15thNight
75%7%8%6%1
2925
16th to endNight
82%8%6%1
3120

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
15%8%32%24%16%2
90
16th to endDay
36%17%27%10%8%
96
February1st to 15thDay
25%21%35%14%4
119
16th to endDay
16%19%33%21%7%
282
March1st to 15thDay
27%30%26%12%2
312
16th to endDay
25%25%31%16%1
288
April1st to 15thDay
22%24%26%21%3
269
16th to endDay
25%24%28%16%5%
270
May1st to 15thDay
23%18%28%24%4
288
16th to endDay
21%12%24%24%14%1
449
June1st to 15thDay
26%13%24%26%8%
495
16th to endDay
16%11%33%29%8%
624
July1st to 15thDay
10%9%25%40%13%
460
16th to endDay
12%11%40%25%7%1
327
August1st to 15thDay
7%11%28%38%10%2
315
16th to endDay
9%17%31%30%10%1
332
September1st to 15thDay
15%15%32%25%9%
315
16th to endDay
18%19%28%23%10%
315
October1st to 15thDay
25%16%33%16%8%
294
16th to endDay
36%11%26%20%4
144
November1st to 15thDay
32%10%33%17%6%
116
16th to endDay
27%18%30%14%35%
90
December1st to 15thDay
18%13%27%21%15%3
90
16th to endDay
20%15%42%15%5%
96
January1st to 15thNight
37%11%27%18%4
861
16th to endNight
26%11%35%23%3
832
February1st to 15thNight
31%10%29%21%6%
764
16th to endNight
20%10%35%25%8%
684
March1st to 15thNight
25%15%32%19%6%
764
16th to endNight
23%11%37%21%5%
768
April1st to 15thNight
19%11%30%29%9%
719
16th to endNight
21%7%31%32%6%
504
May1st to 15thNight
13%8%30%35%11%
360
16th to endNight
18%5%24%36%14%
375
June1st to 15thNight
21%8%23%34%11%
360
16th to endNight
15%6%30%34%13%
360
July1st to 15thNight
8%320%50%16%
340
16th to endNight
6%223%47%20%
376
August1st to 15thNight
7%310%47%31%
360
16th to endNight
7%323%43%22%
604
September1st to 15thNight
10%424%35%24%
720
16th to endNight
18%5%26%32%16%
716
October1st to 15thNight
20%7%30%33%7%
720
16th to endNight
30%8%29%25%6%
768
November1st to 15thNight
35%13%32%13%3
760
16th to endNight
32%14%30%17%5%
949
December1st to 15thNight
27%11%35%21%4
975
16th to endNight
29%12%40%14%2
1040
Page generated at 2018-03-12 10:28:14. Version ac04

Copyright 2018 A. Danko


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