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 2017-04-01.

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%
14348
10%
45198
8%
14319
48%
14319
17%
32885

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
27%
726
4%
2544
4%
722
29%
722
5%
2210
January16th to endNight
32%
768
5%
2688
3%
768
35%
768
8%
2231
February1st to 15thNight
38%
700
6%
2385
5%
699
40%
699
11%
1891
February16th to endNight
47%
632
10%
1963
9%
632
49%
632
17%
1436
March1st to 15thNight
36%
720
6%
2160
5%
720
38%
720
13%
1696
March16th to endNight
43%
768
10%
2003
5%
768
46%
768
17%
1554
April1st to 15thNight
51%
663
9%
1659
4%
663
53%
663
23%
1226
April16th to endNight
47%
460
11%
1450
9%
460
50%
460
18%
1036
May1st to 15thNight
56%
329
13%
1319
19%
329
59%
329
21%
799
May16th to endNight
57%
342
5%
1352
8%
342
58%
342
16%
918
June1st to 15thNight
52%
330
3%
1089
1%
330
52%
330
20%
729
June16th to endNight
64%
330
4%
990
0%
330
64%
330
25%
664
July1st to 15thNight
73%
310
8%
1084
4%
310
74%
310
37%
553
July16th to endNight
76%
348
14%
1304
20%
326
79%
326
43%
567
August1st to 15thNight
83%
330
22%
1312
31%
328
85%
328
40%
591
August16th to endNight
73%
575
23%
1625
20%
575
74%
575
42%
896
September1st to 15thNight
68%
660
23%
1650
13%
660
71%
660
43%
978
September16th to endNight
62%
656
20%
1779
15%
656
64%
656
31%
1148
October1st to 15thNight
55%
660
14%
1980
12%
660
57%
660
25%
1308
October16th to endNight
43%
704
10%
2269
8%
704
47%
704
16%
1634
November1st to 15thNight
33%
700
9%
2388
9%
700
36%
700
11%
1873
November16th to endNight
29%
786
5%
2586
3%
786
32%
786
7%
2175
December1st to 15thNight
31%
900
6%
2700
4%
900
33%
900
10%
2256
December16th to endNight
25%
951
4%
2919
2%
951
28%
951
7%
2516

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
8%7%37%6%46%6%6%7%35%
45905
Night
8%9%47%6%35%5%5%7%34%
45359
Cloud CoverDay
9%7%37%6%46%6%6%7%33%
45905
Night
8%9%47%6%46%6%6%7%33%
45362
TransparencyDay
47%11%15%17%7%1
45569
Night
49%10%15%16%7%
45199
SeeingDay
13%12%30%26%13%3
5369
Night
13%5%25%32%19%3
14354

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
10%11%6%11%9%48%6%7%8%15%
1388
16th to endDay
7%14%410%11%47%6%48%20%
1536
February1st to 15thDay
7%14%6%8%8%5%5%6%7%5%23%
1477
16th to endDay
6%10%49%9%46%6%6%8%27%
1510
March1st to 15thDay
6%8%49%8%37%7%6%8%28%
1800
16th to endDay
7%8%39%9%47%8%7%8%23%
2220
April1st to 15thDay
8%9%49%6%47%5%6%10%27%
1974
16th to endDay
7%9%47%7%46%6%5%8%31%
2178
May1st to 15thDay
9%7%36%6%45%6%6%7%37%
2301
16th to endDay
12%7%37%7%46%6%6%9%29%
2407
June1st to 15thDay
16%6%35%7%46%5%6%6%30%
2538
16th to endDay
11%5%35%5%46%5%6%8%36%
2640
July1st to 15thDay
5%3235%35%5%6%7%52%
2467
16th to endDay
421342445%7%58%
2461
August1st to 15thDay
33144345%6%8%52%
2310
16th to endDay
5%315%5%3446%8%50%
2223
September1st to 15thDay
5%4145%335%45%56%
1980
16th to endDay
10%5%24435%6%5%8%44%
1848
October1st to 15thDay
9%7%26%6%45%5%5%7%39%
1650
16th to endDay
14%8%37%6%45%45%8%30%
1603
November1st to 15thDay
11%11%5%9%6%46%5%6%8%24%
1470
16th to endDay
7%10%7%10%8%5%8%7%6%7%19%
1359
December1st to 15thDay
6%12%7%11%8%47%6%6%6%21%
1260
16th to endDay
8%12%6%10%8%47%7%7%8%18%
1305
January1st to 15thNight
12%16%7%12%8%5%6%6%5%5%13%
2544
16th to endNight
8%15%7%12%9%45%46%7%17%
2688
February1st to 15thNight
11%14%5%8%7%35%5%6%8%23%
2373
16th to endNight
6%10%5%6%7%5%6%5%5%7%32%
1963
March1st to 15thNight
8%10%48%6%45%5%6%9%29%
2160
16th to endNight
7%8%47%7%37%6%6%8%32%
1999
April1st to 15thNight
7%7%26%7%45%7%7%8%36%
1659
16th to endNight
7%7%46%6%5%7%6%5%7%35%
1450
May1st to 15thNight
8%7%25%5%2445%8%44%
1319
16th to endNight
12%7%36%5%25%6%7%8%34%
1352
June1st to 15thNight
11%5%36%6%35%5%48%38%
1089
16th to endNight
7%5%245%37%6%6%7%43%
990
July1st to 15thNight
2112335%46%8%59%
1157
16th to endNight
5%131235%7%65%
1400
August1st to 15thNight
32232436%8%63%
1320
16th to endNight
33133245%5%8%58%
1625
September1st to 15thNight
5%313423445%60%
1650
16th to endNight
7%4144235%5%8%50%
1779
October1st to 15thNight
7%5%25%5%35%5%6%6%45%
1980
16th to endNight
11%8%36%6%35%46%8%34%
2269
November1st to 15thNight
14%11%47%6%35%46%7%28%
2388
16th to endNight
10%14%8%9%9%46%5%6%7%18%
2586
December1st to 15thNight
9%16%7%10%6%46%5%5%6%19%
2700
16th to endNight
9%15%7%11%10%5%7%5%47%16%
2919

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
12%11%6%11%7%47%8%6%8%14%
1388
16th to endDay
9%11%5%9%7%5%7%7%8%7%21%
1536
February1st to 15thDay
7%14%5%10%7%5%8%6%6%5%21%
1477
16th to endDay
6%10%5%9%9%47%6%7%8%24%
1510
March1st to 15thDay
7%10%311%9%47%7%6%7%25%
1800
16th to endDay
8%9%5%9%8%5%7%7%6%8%22%
2220
April1st to 15thDay
9%11%48%6%5%7%6%7%7%25%
1974
16th to endDay
8%10%47%7%36%6%5%8%29%
2178
May1st to 15thDay
10%8%35%6%35%5%6%8%36%
2301
16th to endDay
13%7%36%6%5%7%5%7%7%28%
2407
June1st to 15thDay
17%6%37%7%5%5%45%6%30%
2538
16th to endDay
13%5%26%6%46%6%6%8%33%
2640
July1st to 15thDay
5%2144345%6%8%51%
2467
16th to endDay
42133245%6%7%58%
2461
August1st to 15thDay
3214435%5%6%8%53%
2310
16th to endDay
5%3245%25%47%8%49%
2223
September1st to 15thDay
6%3234245%46%55%
1980
16th to endDay
10%424435%5%5%8%43%
1848
October1st to 15thDay
8%8%36%6%36%5%6%6%38%
1650
16th to endDay
13%8%38%6%35%6%6%8%28%
1603
November1st to 15thDay
12%12%6%9%7%47%6%5%6%22%
1470
16th to endDay
8%11%5%9%10%6%8%8%7%7%17%
1359
December1st to 15thDay
6%10%6%10%8%5%8%7%8%7%18%
1260
16th to endDay
8%12%5%9%8%5%8%8%6%8%17%
1305
January1st to 15thNight
13%14%7%10%8%48%7%5%6%12%
2543
16th to endNight
8%13%6%10%8%5%8%7%6%7%17%
2688
February1st to 15thNight
10%12%5%8%7%46%6%6%7%24%
2373
16th to endNight
6%10%48%6%46%5%5%8%32%
1963
March1st to 15thNight
8%9%48%8%47%6%6%9%26%
2160
16th to endNight
8%8%37%6%46%7%6%8%30%
2003
April1st to 15thNight
7%7%27%6%45%7%7%9%34%
1659
16th to endNight
7%7%37%6%47%5%5%7%35%
1450
May1st to 15thNight
7%7%36%5%25%45%8%44%
1319
16th to endNight
11%7%36%5%35%5%7%9%33%
1352
June1st to 15thNight
12%6%35%5%35%5%5%7%37%
1089
16th to endNight
8%435%445%6%7%8%40%
990
July1st to 15thNight
3133245%6%8%59%
1157
16th to endNight
4111113447%66%
1400
August1st to 15thNight
41223435%7%63%
1320
16th to endNight
43133235%6%8%56%
1625
September1st to 15thNight
5%31442345%5%59%
1650
16th to endNight
7%425%4245%5%7%49%
1779
October1st to 15thNight
8%5%26%5%35%45%6%43%
1980
16th to endNight
12%8%46%6%345%6%7%33%
2269
November1st to 15thNight
14%12%5%7%6%346%5%7%26%
2388
16th to endNight
11%12%6%11%8%46%6%7%6%18%
2586
December1st to 15thNight
8%15%7%9%8%46%7%6%6%19%
2700
16th to endNight
8%14%5%12%8%6%8%7%6%6%15%
2919

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%13%14%6%
1388
16th to endDay
59%12%15%9%11
1536
February1st to 15thDay
60%14%13%9%1
1477
16th to endDay
54%13%17%10%4
1510
March1st to 15thDay
53%13%17%12%2
1800
16th to endDay
58%11%15%10%3
2220
April1st to 15thDay
55%11%15%13%3
1974
16th to endDay
51%12%14%16%5%
2178
May1st to 15thDay
43%10%14%19%10%
2301
16th to endDay
51%11%17%15%4
2411
June1st to 15thDay
52%8%15%13%7%2
2538
16th to endDay
45%11%13%18%9%
2640
July1st to 15thDay
29%8%15%23%17%5%
2311
16th to endDay
23%7%16%27%19%4
2294
August1st to 15thDay
26%9%17%30%13%3
2293
16th to endDay
29%10%14%26%16%2
2223
September1st to 15thDay
28%7%16%28%18%1
1980
16th to endDay
39%9%18%21%9%2
1848
October1st to 15thDay
43%10%18%21%5%
1650
16th to endDay
53%12%15%16%2
1603
November1st to 15thDay
60%12%11%11%2
1470
16th to endDay
62%12%13%9%2
1359
December1st to 15thDay
60%14%11%12%1
1260
16th to endDay
62%15%13%7%1
1305
January1st to 15thNight
70%10%10%6%1
2544
16th to endNight
65%10%12%9%2
2688
February1st to 15thNight
58%11%14%11%3
2385
16th to endNight
50%9%18%15%5%
1963
March1st to 15thNight
52%14%17%11%3
2160
16th to endNight
50%12%16%16%3
2003
April1st to 15thNight
44%11%21%17%4
1659
16th to endNight
46%11%17%20%4
1450
May1st to 15thNight
38%8%17%21%13%
1320
16th to endNight
45%11%19%18%4
1352
June1st to 15thNight
42%10%15%21%8%2
1089
16th to endNight
36%13%17%22%8%
990
July1st to 15thNight
23%8%17%27%19%4
1084
16th to endNight
17%6%16%30%24%4
1304
August1st to 15thNight
20%6%17%33%18%2
1312
16th to endNight
22%8%16%31%18%2
1625
September1st to 15thNight
25%6%15%28%20%3
1650
16th to endNight
32%10%13%26%12%3
1779
October1st to 15thNight
39%9%18%22%9%
1980
16th to endNight
48%11%16%21%2
2269
November1st to 15thNight
56%12%12%13%4
2388
16th to endNight
65%11%11%7%3
2586
December1st to 15thNight
62%12%12%10%1
2700
16th to endNight
66%12%12%7%1
2919

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
3323%25%35%10%
60
16th to endDay
17%334%31%9%4
64
February1st to 15thDay
10%13%38%22%11%2
137
16th to endDay
14%11%31%29%9%3
227
March1st to 15thDay
16%24%37%15%5%
270
16th to endDay
19%21%34%18%5%
288
April1st to 15thDay
20%17%30%19%9%1
211
16th to endDay
16%22%30%17%9%3
210
May1st to 15thDay
15%17%33%23%7%2
228
16th to endDay
18%11%21%28%15%4
282
June1st to 15thDay
19%9%25%24%18%2
483
16th to endDay
12%8%29%29%16%2
585
July1st to 15thDay
7%12%23%35%18%3
395
16th to endDay
49%31%34%15%4
271
August1st to 15thDay
6%8%26%35%18%4
255
16th to endDay
7%13%30%35%9%3
268
September1st to 15thDay
9%13%29%26%16%4
255
16th to endDay
15%10%31%23%14%3
255
October1st to 15thDay
18%14%32%21%9%3
255
16th to endDay
17%427%32%15%2
115
November1st to 15thDay
18%14%40%18%8%
71
16th to endDay
13%10%26%23%18%8%
60
December1st to 15thDay
8%6%40%21%16%6%
60
16th to endDay
9%439%35%9%1
64
January1st to 15thNight
22%6%29%28%11%1
726
16th to endNight
14%5%33%30%12%2
768
February1st to 15thNight
19%5%26%31%15%1
704
16th to endNight
11%5%25%35%19%2
632
March1st to 15thNight
12%9%32%30%12%1
720
16th to endNight
12%6%29%34%14%2
768
April1st to 15thNight
9%8%20%35%21%3
663
16th to endNight
11%5%28%35%16%2
460
May1st to 15thNight
10%5%19%40%22%2
330
16th to endNight
14%5%14%29%31%4
343
June1st to 15thNight
12%222%36%23%2
330
16th to endNight
10%416%45%20%3
330
July1st to 15thNight
4215%36%37%4
310
16th to endNight
5%213%39%35%4
348
August1st to 15thNight
5%8%31%48%5%
330
16th to endNight
6%311%39%33%5%
575
September1st to 15thNight
7%314%29%34%10%
660
16th to endNight
12%415%37%24%6%
656
October1st to 15thNight
11%422%34%23%3
660
16th to endNight
17%5%27%30%14%3
704
November1st to 15thNight
20%8%32%29%8%1
700
16th to endNight
19%8%30%27%11%3
786
December1st to 15thNight
17%7%31%29%12%2
900
16th to endNight
16%5%39%27%9%
951
Page generated at 2017-04-02 04:39:10. Version ac04

Copyright 2017 A. Danko


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