Kelowna
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kelowna 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
46%
15519
10%
48912
8%
15490
48%
15490
17%
35347

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
26%
789
3%
2756
3%
785
28%
785
6%
2384
January16th to endNight
28%
832
5%
2912
3%
832
31%
832
8%
2408
February1st to 15thNight
35%
760
7%
2587
6%
759
37%
759
11%
2051
February16th to endNight
45%
684
10%
2126
10%
684
48%
684
17%
1553
March1st to 15thNight
36%
764
7%
2292
5%
764
38%
764
14%
1794
March16th to endNight
41%
768
10%
2002
5%
768
44%
768
17%
1553
April1st to 15thNight
50%
719
9%
1799
4%
719
52%
719
22%
1334
April16th to endNight
48%
501
12%
1581
10%
501
50%
501
18%
1133
May1st to 15thNight
57%
359
12%
1439
18%
359
60%
359
21%
871
May16th to endNight
57%
374
7%
1478
9%
374
58%
374
16%
989
June1st to 15thNight
54%
360
3%
1188
1%
360
54%
360
21%
779
June16th to endNight
64%
360
5%
1080
0%
360
64%
360
26%
711
July1st to 15thNight
75%
340
8%
1191
4%
340
76%
340
39%
592
July16th to endNight
77%
376
15%
1416
23%
354
81%
354
44%
607
August1st to 15thNight
83%
360
21%
1432
30%
358
85%
358
42%
629
August16th to endNight
74%
628
25%
1774
22%
628
76%
628
44%
958
September1st to 15thNight
70%
720
22%
1800
12%
720
72%
720
46%
1048
September16th to endNight
63%
716
21%
1942
16%
716
65%
716
32%
1251
October1st to 15thNight
56%
720
13%
2160
12%
720
58%
720
25%
1418
October16th to endNight
44%
768
12%
2474
9%
768
48%
768
17%
1749
November1st to 15thNight
32%
760
9%
2594
8%
760
35%
760
11%
2056
November16th to endNight
28%
852
5%
2802
2%
852
31%
852
7%
2358
December1st to 15thNight
33%
975
6%
2925
4%
975
34%
975
10%
2410
December16th to endNight
24%
1034
5%
3162
3%
1034
26%
1034
8%
2711

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%7%37%6%46%6%6%8%35%
49712
Night
8%9%47%7%45%5%6%7%33%
49073
Cloud CoverDay
8%7%37%6%46%6%6%7%35%
49712
Night
8%9%47%7%45%5%6%7%33%
49076
TransparencyDay
46%10%15%17%8%1
49376
Night
48%10%15%17%7%
48913
SeeingDay
13%12%29%26%14%3
6578
Night
13%5%24%32%19%3
15525

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
11%12%5%10%9%5%9%7%8%7%12%
1505
16th to endDay
8%12%5%10%10%5%6%6%6%8%20%
1664
February1st to 15thDay
8%12%6%9%8%5%7%5%6%6%22%
1604
16th to endDay
6%9%5%8%9%5%7%7%7%8%25%
1633
March1st to 15thDay
5%8%5%10%8%5%7%6%7%7%27%
1904
16th to endDay
7%8%410%9%49%7%7%8%23%
2220
April1st to 15thDay
8%10%5%8%7%45%7%7%9%25%
2149
16th to endDay
7%9%48%7%47%6%6%8%30%
2376
May1st to 15thDay
8%7%36%6%46%7%5%7%36%
2511
16th to endDay
11%6%37%7%45%6%7%8%30%
2630
June1st to 15thDay
14%6%36%6%47%6%6%7%30%
2769
16th to endDay
10%5%36%5%46%6%6%8%37%
2880
July1st to 15thDay
33234345%6%7%54%
2690
16th to endDay
41133245%5%7%60%
2657
August1st to 15thDay
32134345%6%9%55%
2520
16th to endDay
42145%35%46%9%52%
2425
September1st to 15thDay
4315%5%2445%6%56%
2160
16th to endDay
8%4245%26%5%6%8%43%
2016
October1st to 15thDay
8%7%37%6%46%6%5%7%37%
1800
16th to endDay
12%8%38%6%45%5%6%8%30%
1749
November1st to 15thDay
11%11%5%9%7%47%5%7%6%21%
1595
16th to endDay
7%10%6%9%11%6%8%7%7%7%17%
1475
December1st to 15thDay
411%6%11%9%5%8%8%7%6%19%
1365
16th to endDay
8%12%6%10%8%5%7%8%6%8%17%
1415
January1st to 15thNight
11%16%7%12%9%5%8%6%5%5%11%
2756
16th to endNight
8%13%6%13%10%5%7%5%5%7%16%
2912
February1st to 15thNight
12%13%6%9%7%35%5%6%7%22%
2575
16th to endNight
6%10%5%7%7%46%45%7%32%
2126
March1st to 15thNight
7%12%5%8%7%45%5%6%8%27%
2292
16th to endNight
7%8%47%7%5%6%6%6%8%31%
1998
April1st to 15thNight
6%7%36%7%46%6%7%7%34%
1799
16th to endNight
7%7%36%7%5%6%6%7%6%34%
1581
May1st to 15thNight
6%7%36%5%345%5%9%43%
1439
16th to endNight
10%7%37%6%35%6%6%9%34%
1478
June1st to 15thNight
10%6%36%6%35%5%5%8%39%
1188
16th to endNight
6%415%5%45%7%6%7%44%
1080
July1st to 15thNight
2112335%46%9%60%
1264
16th to endNight
41122335%7%66%
1512
August1st to 15thNight
31232336%8%64%
1440
16th to endNight
32133245%5%8%59%
1774
September1st to 15thNight
431433335%5%61%
1800
16th to endNight
6%425%4245%48%50%
1942
October1st to 15thNight
7%5%35%5%35%5%6%6%44%
2160
16th to endNight
10%8%37%6%35%5%5%9%35%
2474
November1st to 15thNight
13%12%5%8%6%45%5%5%6%25%
2594
16th to endNight
9%13%8%10%9%47%6%6%7%17%
2802
December1st to 15thNight
7%15%6%10%8%5%7%6%6%6%19%
2925
16th to endNight
8%15%7%12%10%47%6%5%6%15%
3162

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
11%11%6%11%9%48%7%7%8%13%
1505
16th to endDay
8%11%49%9%5%9%6%7%7%20%
1664
February1st to 15thDay
7%12%7%9%8%5%7%6%6%6%22%
1604
16th to endDay
6%10%5%7%10%5%6%6%7%8%25%
1633
March1st to 15thDay
6%9%410%8%47%6%7%7%27%
1904
16th to endDay
7%8%5%8%9%5%7%8%6%8%23%
2220
April1st to 15thDay
8%10%48%7%46%6%7%8%25%
2149
16th to endDay
7%9%48%7%47%5%6%9%29%
2376
May1st to 15thDay
8%8%36%6%46%5%5%9%36%
2511
16th to endDay
12%6%36%6%36%6%6%8%31%
2630
June1st to 15thDay
14%7%27%6%5%5%5%6%6%30%
2769
16th to endDay
11%5%35%6%46%5%6%7%37%
2880
July1st to 15thDay
431343446%8%54%
2690
16th to endDay
311332445%7%60%
2657
August1st to 15thDay
32144345%5%8%56%
2520
16th to endDay
5%214435%5%6%8%53%
2425
September1st to 15thDay
5%31443345%5%57%
2160
16th to endDay
9%5%25%435%5%6%8%43%
2016
October1st to 15thDay
8%7%26%7%46%46%7%38%
1800
16th to endDay
12%9%27%7%35%5%6%8%30%
1749
November1st to 15thDay
11%11%6%10%7%47%6%6%6%22%
1595
16th to endDay
8%10%5%11%11%5%7%7%7%7%18%
1475
December1st to 15thDay
411%5%9%11%5%9%8%7%6%20%
1365
16th to endDay
8%12%5%10%8%48%8%6%8%16%
1415
January1st to 15thNight
12%15%7%11%9%5%7%6%6%5%11%
2755
16th to endNight
8%12%7%12%10%6%7%6%6%6%16%
2912
February1st to 15thNight
10%13%5%9%7%45%5%6%7%22%
2575
16th to endNight
6%10%49%7%46%5%5%7%32%
2126
March1st to 15thNight
7%10%5%8%7%46%5%6%8%28%
2292
16th to endNight
7%8%37%7%46%6%6%9%31%
2002
April1st to 15thNight
6%7%26%7%46%6%7%8%34%
1799
16th to endNight
7%7%36%7%47%5%6%7%35%
1581
May1st to 15thNight
6%7%35%5%2445%8%43%
1439
16th to endNight
10%7%37%5%35%6%7%8%34%
1478
June1st to 15thNight
10%5%35%5%45%46%8%38%
1188
16th to endNight
7%425%6%35%7%7%8%43%
1080
July1st to 15thNight
2112325%5%6%8%60%
1264
16th to endNight
41121235%7%67%
1512
August1st to 15thNight
31222335%7%65%
1440
16th to endNight
33133235%48%59%
1774
September1st to 15thNight
4314323445%61%
1800
16th to endNight
7%425%4235%6%7%50%
1942
October1st to 15thNight
7%6%25%6%35%5%6%7%44%
2160
16th to endNight
10%8%27%6%345%6%8%35%
2474
November1st to 15thNight
13%11%49%6%46%5%5%7%25%
2594
16th to endNight
9%12%7%10%11%46%5%6%6%17%
2802
December1st to 15thNight
7%13%7%10%7%47%6%6%6%20%
2925
16th to endNight
8%14%7%12%10%5%7%6%5%6%15%
3162

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
64%14%14%5%
1505
16th to endDay
59%12%15%10%11
1664
February1st to 15thDay
59%13%12%10%2
1604
16th to endDay
54%13%17%10%3
1633
March1st to 15thDay
53%13%18%12%2
1904
16th to endDay
58%11%15%10%3
2220
April1st to 15thDay
56%11%15%12%3
2149
16th to endDay
51%12%14%16%5%
2376
May1st to 15thDay
43%10%14%19%10%1
2511
16th to endDay
49%11%17%17%4
2634
June1st to 15thDay
51%8%15%14%7%1
2769
16th to endDay
44%10%13%19%11%
2880
July1st to 15thDay
28%7%14%23%19%6%
2534
16th to endDay
22%6%15%27%22%4
2490
August1st to 15thDay
24%8%17%29%15%4
2503
16th to endDay
28%9%14%28%17%2
2425
September1st to 15thDay
27%6%15%27%20%1
2160
16th to endDay
38%9%19%21%9%2
2016
October1st to 15thDay
44%10%19%20%5%
1800
16th to endDay
51%12%15%16%3
1749
November1st to 15thDay
61%12%11%11%2
1595
16th to endDay
62%12%13%9%2
1475
December1st to 15thDay
58%14%11%13%1
1365
16th to endDay
61%14%13%7%2
1415
January1st to 15thNight
69%11%10%6%1
2756
16th to endNight
64%10%12%9%2
2912
February1st to 15thNight
58%11%13%11%4
2587
16th to endNight
51%8%18%16%5%
2126
March1st to 15thNight
52%13%17%12%3
2292
16th to endNight
50%12%16%16%3
2002
April1st to 15thNight
44%11%20%17%5%
1799
16th to endNight
47%10%16%20%4
1581
May1st to 15thNight
38%8%17%20%13%
1440
16th to endNight
44%10%18%20%5%
1478
June1st to 15thNight
41%10%15%22%8%2
1188
16th to endNight
35%12%17%23%10%
1080
July1st to 15thNight
22%7%16%26%20%6%
1191
16th to endNight
17%6%16%28%26%5%
1416
August1st to 15thNight
19%6%16%32%21%4
1432
16th to endNight
21%8%15%32%19%2
1774
September1st to 15thNight
24%6%14%28%22%3
1800
16th to endNight
32%10%14%26%12%3
1942
October1st to 15thNight
39%9%18%22%9%
2160
16th to endNight
46%10%17%21%3
2474
November1st to 15thNight
57%12%12%12%4
2594
16th to endNight
66%10%12%7%3
2802
December1st to 15thNight
60%12%13%11%1
2925
16th to endNight
66%11%11%7%2
3162

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
8%220%23%31%14%
90
16th to endDay
19%8%31%28%8%4
96
February1st to 15thDay
14%11%38%24%9%1
174
16th to endDay
13%11%31%31%9%3
273
March1st to 15thDay
15%22%35%17%7%
312
16th to endDay
19%21%34%18%5%
288
April1st to 15thDay
20%16%31%20%8%1
269
16th to endDay
15%20%34%18%8%2
270
May1st to 15thDay
12%18%34%23%7%2
288
16th to endDay
17%11%19%28%17%5%
345
June1st to 15thDay
16%9%25%25%19%3
564
16th to endDay
11%9%30%28%16%3
675
July1st to 15thDay
6%10%24%36%19%3
468
16th to endDay
5%9%29%35%16%3
327
August1st to 15thDay
5%7%23%33%21%8%
315
16th to endDay
6%11%28%32%14%6%
332
September1st to 15thDay
8%12%27%27%19%4
315
16th to endDay
14%9%29%24%15%5%
315
October1st to 15thDay
17%13%32%22%10%3
315
16th to endDay
17%8%27%29%15%1
165
November1st to 15thDay
19%13%33%19%11%1
106
16th to endDay
17%14%31%18%12%5%
90
December1st to 15thDay
6%431%23%21%13%
90
16th to endDay
14%5%31%39%8%1
96
January1st to 15thNight
22%6%28%28%12%2
789
16th to endNight
13%6%34%31%11%2
832
February1st to 15thNight
20%6%26%31%14%1
764
16th to endNight
11%5%24%36%19%2
684
March1st to 15thNight
13%9%31%30%13%2
764
16th to endNight
12%6%29%34%14%2
768
April1st to 15thNight
9%8%21%36%20%3
719
16th to endNight
11%5%26%36%16%2
501
May1st to 15thNight
11%419%41%21%1
360
16th to endNight
14%413%29%32%4
375
June1st to 15thNight
12%221%36%23%2
360
16th to endNight
9%416%45%21%3
360
July1st to 15thNight
3214%35%39%3
340
16th to endNight
5%212%39%35%4
376
August1st to 15thNight
48%30%48%7%
360
16th to endNight
5%310%38%35%5%
628
September1st to 15thNight
7%214%30%34%10%
720
16th to endNight
12%314%36%26%6%
716
October1st to 15thNight
11%421%34%24%3
720
16th to endNight
16%5%28%31%14%3
768
November1st to 15thNight
20%8%32%28%10%1
760
16th to endNight
19%8%31%26%10%3
852
December1st to 15thNight
16%6%29%29%14%2
975
16th to endNight
17%5%37%29%9%
1034
Page generated at 2018-03-12 10:28:09. Version ac04

Copyright 2018 A. Danko


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