Wetaskiwin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wetaskiwin clear sky chart from 2005-11-05 to 2017-12-20.

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
41%
15612
10%
48041
7%
15586
44%
15586
18%
34372

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
33%
895
8%
2685
5%
895
36%
895
13%
2075
January16th to endNight
30%
891
15%
2811
8%
891
38%
891
16%
2004
February1st to 15thNight
41%
699
9%
2429
8%
698
45%
698
15%
1726
February16th to endNight
44%
632
11%
2016
12%
632
46%
632
18%
1423
March1st to 15thNight
41%
720
12%
2109
9%
720
45%
720
18%
1557
March16th to endNight
38%
768
9%
2094
5%
767
41%
767
17%
1614
April1st to 15thNight
38%
599
11%
1679
6%
599
41%
599
17%
1265
April16th to endNight
41%
540
10%
1620
9%
540
44%
540
18%
1164
May1st to 15thNight
44%
392
8%
1326
7%
392
46%
392
16%
928
May16th to endNight
41%
374
1%
1309
1%
374
41%
374
14%
960
June1st to 15thNight
40%
360
0%
1260
0%
360
40%
360
12%
941
June16th to endNight
47%
360
0%
1260
0%
360
47%
360
16%
881
July1st to 15thNight
56%
340
0%
1190
0%
340
56%
340
21%
775
July16th to endNight
56%
376
3%
1239
3%
354
57%
354
21%
786
August1st to 15thNight
62%
381
6%
1418
8%
379
63%
379
21%
900
August16th to endNight
61%
573
12%
1719
11%
573
62%
573
26%
1120
September1st to 15thNight
57%
627
15%
1779
11%
627
58%
627
29%
1139
September16th to endNight
52%
716
19%
1980
13%
716
57%
716
33%
1249
October1st to 15thNight
42%
720
14%
2144
9%
720
46%
720
21%
1491
October16th to endNight
40%
768
15%
2496
10%
768
48%
768
19%
1722
November1st to 15thNight
34%
947
13%
2677
8%
947
38%
947
17%
2013
November16th to endNight
29%
975
10%
2925
6%
975
33%
975
15%
2233
December1st to 15thNight
31%
975
10%
2925
6%
975
34%
975
14%
2240
December16th to endNight
36%
984
13%
2951
6%
984
42%
984
17%
2166

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%9%47%6%35%5%6%8%32%
48836
Night
9%9%48%7%35%5%6%8%31%
48193
TransparencyDay
48%9%17%18%5%
48486
Night
49%8%15%18%6%
48047
SeeingDay
14%6%23%30%19%5%
6354
Night
13%5%27%34%16%2
15624

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
413%5%9%10%5%6%5%47%27%
1253
16th to endDay
6%13%5%10%7%26%46%9%26%
1423
February1st to 15thDay
7%11%49%7%36%5%6%7%29%
1432
16th to endDay
5%11%7%9%7%47%7%7%7%23%
1457
March1st to 15thDay
7%11%5%9%8%45%6%7%7%25%
1851
16th to endDay
12%12%6%8%6%25%6%5%8%23%
2125
April1st to 15thDay
14%10%5%8%6%4445%7%27%
2269
16th to endDay
15%10%36%6%35%5%5%8%29%
2340
May1st to 15thDay
9%9%37%6%35%6%5%8%33%
2623
16th to endDay
19%7%35%6%46%5%5%7%29%
2802
June1st to 15thDay
16%8%38%7%36%5%5%8%26%
2700
16th to endDay
14%6%35%6%35%6%6%9%32%
2700
July1st to 15thDay
11%5%25%5%35%47%9%39%
2700
16th to endDay
10%424435%6%6%9%41%
2846
August1st to 15thDay
11%425%5%35%6%7%9%37%
2532
16th to endDay
8%5%25%5%3447%10%42%
2483
September1st to 15thDay
13%6%25%5%3445%7%41%
2178
16th to endDay
11%5%15%4345%5%9%44%
1980
October1st to 15thDay
12%9%46%6%35%445%36%
1815
16th to endDay
10%12%45%5%35%5%5%7%34%
1719
November1st to 15thDay
8%13%7%9%6%45%5%5%6%27%
1506
16th to endDay
6%10%6%11%6%45%5%5%7%29%
1365
December1st to 15thDay
6%14%7%10%10%5%6%445%23%
1365
16th to endDay
5%13%5%9%8%46%5%5%9%24%
1372
January1st to 15thNight
7%12%5%10%9%5%6%6%6%7%23%
2685
16th to endNight
6%11%49%8%4446%6%31%
2811
February1st to 15thNight
5%9%5%11%8%5%6%5%47%29%
2421
16th to endNight
7%11%5%8%6%346%7%8%30%
2016
March1st to 15thNight
7%9%49%8%46%6%5%9%28%
2109
16th to endNight
10%13%6%9%6%35%5%7%8%22%
2094
April1st to 15thNight
10%10%48%6%46%5%7%7%28%
1679
16th to endNight
15%10%46%5%25%5%5%8%30%
1620
May1st to 15thNight
9%9%6%6%7%36%6%6%7%29%
1325
16th to endNight
19%7%38%6%445%5%6%27%
1309
June1st to 15thNight
19%8%36%6%36%6%7%8%23%
1260
16th to endNight
12%7%37%5%36%7%6%8%29%
1260
July1st to 15thNight
11%425%6%445%6%11%36%
1260
16th to endNight
9%335%6%35%6%7%8%39%
1323
August1st to 15thNight
9%425%6%25%6%7%11%37%
1425
16th to endNight
7%5%35%6%35%5%6%9%40%
1719
September1st to 15thNight
13%5%25%423447%44%
1779
16th to endNight
10%5%2442445%8%48%
1980
October1st to 15thNight
11%10%46%43446%8%34%
2144
16th to endNight
8%8%37%7%35%5%7%8%33%
2496
November1st to 15thNight
9%12%5%8%6%35%5%5%7%28%
2677
16th to endNight
7%12%6%10%8%45%5%46%27%
2925
December1st to 15thNight
8%13%6%10%8%35%45%7%27%
2925
16th to endNight
410%6%10%8%46%5%6%8%26%
2951

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
56%9%14%14%5%
1253
16th to endDay
53%7%13%16%7%1
1423
February1st to 15thDay
51%8%17%15%6%
1432
16th to endDay
54%9%14%15%5%
1457
March1st to 15thDay
54%9%15%15%3
1851
16th to endDay
56%8%15%15%3
2126
April1st to 15thDay
54%7%15%16%6%
2269
16th to endDay
51%8%16%14%7%1
2340
May1st to 15thDay
46%7%16%20%8%
2623
16th to endDay
52%8%14%17%7%
2807
June1st to 15thDay
53%9%15%18%3
2700
16th to endDay
46%11%19%18%3
2700
July1st to 15thDay
40%10%22%23%3
2541
16th to endDay
37%12%25%21%2
2667
August1st to 15thDay
40%13%25%17%3
2514
16th to endDay
34%10%24%22%6%
2483
September1st to 15thDay
41%7%19%22%6%1
2178
16th to endDay
35%8%19%27%7%1
1980
October1st to 15thDay
48%8%17%17%7%
1815
16th to endDay
46%9%14%23%5%
1719
November1st to 15thDay
54%8%14%16%4
1506
16th to endDay
52%9%16%15%4
1365
December1st to 15thDay
62%6%11%14%3
1365
16th to endDay
54%7%14%15%7%
1372
January1st to 15thNight
57%8%15%13%31
2685
16th to endNight
51%6%14%18%7%2
2811
February1st to 15thNight
52%6%14%17%7%
2432
16th to endNight
48%8%15%15%10%
2016
March1st to 15thNight
50%9%14%18%5%
2109
16th to endNight
55%8%14%16%5%
2097
April1st to 15thNight
52%9%13%17%6%1
1679
16th to endNight
50%7%13%17%8%2
1620
May1st to 15thNight
50%7%12%17%11%
1326
16th to endNight
54%7%12%15%7%1
1309
June1st to 15thNight
54%10%15%14%5%
1260
16th to endNight
47%10%20%16%3
1260
July1st to 15thNight
39%11%21%23%4
1190
16th to endNight
37%12%24%22%3
1239
August1st to 15thNight
36%13%25%20%3
1418
16th to endNight
36%10%19%25%6%
1719
September1st to 15thNight
38%6%15%25%11%2
1779
16th to endNight
33%7%16%26%12%2
1980
October1st to 15thNight
45%8%15%21%8%
2144
16th to endNight
45%9%17%21%5%
2496
November1st to 15thNight
53%8%13%18%5%1
2677
16th to endNight
56%8%14%13%6%1
2925
December1st to 15thNight
56%7%12%17%5%
2925
16th to endNight
52%7%16%17%5%
2951

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%131%36%16%6%
60
16th to endDay
3325%35%25%7%
64
February1st to 15thDay
15%10%24%33%13%3
66
16th to endDay
9%7%27%35%16%3
116
March1st to 15thDay
10%8%38%28%11%1
270
16th to endDay
17%6%29%33%11%1
288
April1st to 15thDay
14%14%28%30%10%1
269
16th to endDay
23%9%24%24%14%4
270
May1st to 15thDay
11%9%22%31%18%5%
435
16th to endDay
18%421%30%20%5%
517
June1st to 15thDay
19%5%23%31%15%4
495
16th to endDay
15%423%27%20%8%
495
July1st to 15thDay
11%118%33%26%8%
475
16th to endDay
10%6%20%30%26%5%
515
August1st to 15thDay
13%115%29%24%14%
348
16th to endDay
9%6%19%33%26%4
332
September1st to 15thDay
19%423%29%18%5%
315
16th to endDay
13%11%20%31%18%5%
315
October1st to 15thDay
24%6%24%26%15%4
183
16th to endDay
20%9%26%23%17%2
144
November1st to 15thDay
15%426%38%10%3
130
16th to endDay
12%436%28%8%8%
90
December1st to 15thDay
5%7%28%27%26%3
90
16th to endDay
8%436%29%18%4
72
January1st to 15thNight
12%7%31%33%13%1
900
16th to endNight
12%9%32%31%10%2
891
February1st to 15thNight
7%7%26%37%17%1
704
16th to endNight
12%325%35%20%2
632
March1st to 15thNight
10%431%36%14%2
720
16th to endNight
15%427%34%15%2
768
April1st to 15thNight
15%6%29%33%14%1
599
16th to endNight
20%6%23%34%14%1
540
May1st to 15thNight
11%8%25%38%14%2
393
16th to endNight
21%322%32%17%2
375
June1st to 15thNight
22%422%31%15%3
360
16th to endNight
15%320%36%24%1
360
July1st to 15thNight
14%17%42%24%1
340
16th to endNight
10%317%42%24%1
376
August1st to 15thNight
11%118%28%34%5%
381
16th to endNight
8%220%38%28%1
573
September1st to 15thNight
16%117%38%23%2
627
16th to endNight
12%326%39%14%2
716
October1st to 15thNight
16%428%32%15%2
720
16th to endNight
12%5%32%38%11%
768
November1st to 15thNight
15%6%31%33%11%2
947
16th to endNight
13%7%35%31%10%1
975
December1st to 15thNight
14%8%30%29%14%2
975
16th to endNight
9%432%32%17%3
984
Page generated at 2017-12-21 05:04:54. Version ac04

Copyright 2017 A. Danko


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