Weyburn
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weyburn clear sky chart from 2005-11-05 to 2017-04-07.

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
38%
15588
13%
45286
8%
15549
43%
15549
22%
31493

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
29%
896
10%
2506
5%
895
33%
895
15%
1910
January16th to endNight
24%
960
10%
2688
5%
960
29%
960
14%
2083
February1st to 15thNight
29%
810
8%
2399
4%
810
34%
810
13%
1867
February16th to endNight
36%
632
13%
1945
10%
632
40%
632
17%
1454
March1st to 15thNight
34%
720
12%
2160
7%
720
38%
720
19%
1553
March16th to endNight
34%
638
12%
2009
9%
638
39%
638
16%
1495
April1st to 15thNight
37%
515
17%
1718
14%
515
44%
515
24%
1099
April16th to endNight
35%
495
14%
1463
10%
495
40%
495
21%
1015
May1st to 15thNight
43%
495
14%
1320
7%
495
45%
495
28%
881
May16th to endNight
44%
515
8%
1333
5%
513
45%
513
23%
956
June1st to 15thNight
44%
495
4%
1155
1%
495
46%
495
31%
804
June16th to endNight
51%
331
5%
991
6%
331
53%
331
33%
584
July1st to 15thNight
56%
405
8%
1123
6%
405
58%
405
40%
653
July16th to endNight
61%
522
14%
1304
9%
489
63%
489
45%
749
August1st to 15thNight
62%
494
18%
1312
11%
491
66%
491
41%
779
August16th to endNight
61%
525
23%
1625
19%
525
67%
525
44%
842
September1st to 15thNight
54%
495
19%
1650
19%
495
59%
495
31%
946
September16th to endNight
51%
492
24%
1785
23%
492
58%
492
30%
980
October1st to 15thNight
40%
646
20%
1966
12%
646
47%
646
27%
1248
October16th to endNight
40%
872
17%
2280
9%
872
45%
872
27%
1573
November1st to 15thNight
34%
875
16%
2365
6%
875
39%
875
23%
1647
November16th to endNight
30%
900
14%
2619
7%
900
36%
900
17%
1927
December1st to 15thNight
27%
900
6%
2700
4%
900
29%
900
10%
2202
December16th to endNight
29%
960
10%
2870
5%
960
34%
960
13%
2246

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%8%36%6%35%5%5%7%35%
45947
Night
9%9%48%6%35%45%7%35%
45450
Cloud CoverDay
11%8%36%6%35%5%5%7%35%
45957
Night
9%9%47%6%35%45%7%35%
45453
Cloud CoverDay
11%8%37%6%35%5%5%7%35%
45957
Night
9%9%48%6%35%45%7%35%
45455
TransparencyDay
47%7%16%21%7%
45629
Night
46%6%15%21%8%
45286
SeeingDay
14%7%28%29%16%3
5479
Night
13%6%29%34%13%1
15597

By Month

Percentage Cloud Cover NE (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
9%10%6%9%9%47%5%6%6%24%
1432
16th to endDay
6%11%6%11%9%46%6%6%7%22%
1536
February1st to 15thDay
11%12%7%11%9%5%8%5%4420%
1473
16th to endDay
8%13%7%12%9%6%8%8%5%5%15%
1528
March1st to 15thDay
7%12%7%11%9%45%5%6%6%23%
1790
16th to endDay
11%11%5%8%5%45%5%6%9%25%
2211
April1st to 15thDay
11%8%36%6%35%5%5%7%36%
2045
16th to endDay
15%9%25%4345%5%7%35%
2167
May1st to 15thDay
14%9%25%5%23447%38%
2301
16th to endDay
21%7%26%5%245%5%8%29%
2428
June1st to 15thDay
17%5%26%5%35%46%7%34%
2475
16th to endDay
12%4244345%6%10%39%
2634
July1st to 15thDay
7%3235%35%5%5%8%49%
2423
16th to endDay
6%313335%6%6%8%49%
2460
August1st to 15thDay
10%3145%35%46%8%45%
2310
16th to endDay
10%423424347%51%
2222
September1st to 15thDay
13%6%14423447%47%
1980
16th to endDay
13%5%24423346%49%
1844
October1st to 15thDay
17%9%36%32335%6%37%
1658
16th to endDay
13%11%46%42445%6%35%
1584
November1st to 15thDay
9%9%5%8%6%35%446%35%
1493
16th to endDay
9%15%5%8%7%5%5%347%27%
1340
December1st to 15thDay
10%16%8%11%11%5%6%5%5%6%12%
1260
16th to endDay
10%12%5%13%8%5%7%6%46%19%
1353
January1st to 15thNight
7%11%6%9%7%47%6%7%8%23%
2506
16th to endNight
6%12%6%11%7%36%5%6%8%23%
2688
February1st to 15thNight
7%12%6%10%9%5%6%5%5%6%23%
2395
16th to endNight
7%11%5%11%8%36%5%6%7%26%
1945
March1st to 15thNight
7%10%410%8%35%45%8%31%
2147
16th to endNight
11%11%5%8%7%37%45%7%27%
2009
April1st to 15thNight
10%8%46%4245%5%7%40%
1718
16th to endNight
14%10%37%4235%5%5%36%
1463
May1st to 15thNight
13%7%35%435%36%6%41%
1320
16th to endNight
16%5%345%3446%9%34%
1332
June1st to 15thNight
16%42442445%8%41%
1155
16th to endNight
12%31431346%10%47%
991
July1st to 15thNight
6%2134246%6%8%53%
1201
16th to endNight
421442435%7%59%
1400
August1st to 15thNight
6%223424448%54%
1320
16th to endNight
7%21422345%8%57%
1625
September1st to 15thNight
10%5%24423446%50%
1650
16th to endNight
13%424413346%51%
1785
October1st to 15thNight
14%8%24423246%44%
1966
16th to endNight
10%10%35%5%2446%7%38%
2280
November1st to 15thNight
11%9%37%5%3445%7%38%
2365
16th to endNight
9%11%5%9%6%35%45%7%30%
2619
December1st to 15thNight
9%13%7%13%9%45%45%5%18%
2700
16th to endNight
8%12%7%12%9%445%6%6%22%
2870

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
9%10%6%9%9%5%7%5%6%7%23%
1433
16th to endDay
6%11%6%11%9%47%5%7%7%22%
1536
February1st to 15thDay
11%12%6%12%8%49%5%4420%
1473
16th to endDay
8%13%6%11%9%6%8%8%5%5%16%
1528
March1st to 15thDay
8%11%7%11%8%5%5%5%6%6%23%
1800
16th to endDay
11%12%5%8%5%45%5%6%8%25%
2210
April1st to 15thDay
11%9%36%6%35%5%6%7%35%
2045
16th to endDay
15%9%26%5%245%5%7%35%
2167
May1st to 15thDay
14%9%345%2445%8%37%
2301
16th to endDay
21%7%35%5%25%46%8%29%
2428
June1st to 15thDay
17%5%26%5%35%5%5%8%33%
2475
16th to endDay
12%4245%25%5%6%10%39%
2634
July1st to 15thDay
7%3245%35%5%5%9%48%
2423
16th to endDay
5%423435%5%7%9%49%
2460
August1st to 15thDay
9%414435%5%5%9%45%
2310
16th to endDay
9%424423447%51%
2222
September1st to 15thDay
13%5%1442335%7%46%
1980
16th to endDay
12%6%15%423437%49%
1844
October1st to 15thDay
16%10%35%32335%7%37%
1658
16th to endDay
12%12%46%42435%6%36%
1584
November1st to 15thDay
10%9%5%7%5%45%5%46%35%
1493
16th to endDay
9%14%5%9%6%45%447%27%
1340
December1st to 15thDay
10%16%8%11%11%46%6%5%6%13%
1260
16th to endDay
10%12%6%11%8%6%7%6%46%19%
1353
January1st to 15thNight
7%11%5%9%7%47%5%7%8%23%
2506
16th to endNight
6%11%6%11%7%46%6%6%7%23%
2688
February1st to 15thNight
8%12%6%10%8%5%6%6%46%23%
2388
16th to endNight
7%11%5%11%7%37%5%6%7%25%
1945
March1st to 15thNight
6%10%5%10%8%4446%7%30%
2160
16th to endNight
11%11%5%9%7%47%45%7%27%
2006
April1st to 15thNight
10%8%46%42445%7%40%
1718
16th to endNight
14%9%46%5%2445%6%35%
1463
May1st to 15thNight
13%8%25%42445%7%41%
1319
16th to endNight
16%6%245%345%5%9%35%
1333
June1st to 15thNight
15%43442346%8%41%
1155
16th to endNight
11%32441347%9%48%
991
July1st to 15thNight
5%2143346%5%8%53%
1201
16th to endNight
422342335%6%59%
1400
August1st to 15thNight
6%32433336%8%54%
1320
16th to endNight
6%21431335%8%57%
1625
September1st to 15thNight
11%5%24424446%50%
1650
16th to endNight
12%414414347%51%
1785
October1st to 15thNight
13%9%25%42335%6%44%
1966
16th to endNight
10%10%45%5%2445%7%38%
2280
November1st to 15thNight
10%10%36%6%3435%7%38%
2365
16th to endNight
9%11%5%9%6%35%45%7%30%
2619
December1st to 15thNight
9%14%7%13%9%5%5%5%5%5%18%
2700
16th to endNight
7%12%6%12%9%45%5%6%7%22%
2870

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
9%10%5%9%9%5%7%5%7%6%24%
1432
16th to endDay
6%11%6%11%8%47%6%6%7%22%
1536
February1st to 15thDay
11%12%7%11%9%5%8%5%4420%
1473
16th to endDay
8%13%7%12%9%6%8%7%5%5%15%
1528
March1st to 15thDay
7%12%7%11%9%45%5%6%6%23%
1800
16th to endDay
11%11%5%8%5%45%5%7%9%25%
2211
April1st to 15thDay
11%8%37%6%35%5%5%7%36%
2045
16th to endDay
15%10%26%4245%5%7%35%
2167
May1st to 15thDay
14%9%35%5%2345%7%38%
2301
16th to endDay
21%7%26%5%245%5%8%29%
2428
June1st to 15thDay
17%5%26%5%35%5%6%7%34%
2475
16th to endDay
12%424425%5%6%10%39%
2634
July1st to 15thDay
7%3235%35%5%5%8%48%
2423
16th to endDay
6%313335%6%6%8%49%
2460
August1st to 15thDay
10%4145%35%5%6%8%45%
2310
16th to endDay
10%424424347%51%
2222
September1st to 15thDay
13%6%14423447%47%
1980
16th to endDay
13%5%24423346%49%
1844
October1st to 15thDay
16%9%35%32335%6%37%
1658
16th to endDay
13%11%46%42345%6%35%
1584
November1st to 15thDay
9%9%5%8%6%35%5%46%35%
1493
16th to endDay
9%15%49%6%5%6%347%27%
1340
December1st to 15thDay
10%16%8%11%11%5%6%46%6%12%
1260
16th to endDay
10%12%5%13%8%5%7%6%46%19%
1353
January1st to 15thNight
7%11%5%9%7%47%6%7%8%23%
2506
16th to endNight
6%12%7%12%7%36%5%6%8%23%
2688
February1st to 15thNight
7%12%6%10%9%5%6%6%5%6%23%
2388
16th to endNight
7%11%6%11%7%36%5%5%7%25%
1945
March1st to 15thNight
7%10%5%10%8%4445%7%31%
2160
16th to endNight
11%11%5%8%7%37%447%27%
2009
April1st to 15thNight
10%8%46%4245%5%7%40%
1718
16th to endNight
14%10%37%4235%5%5%36%
1463
May1st to 15thNight
13%7%35%33435%6%41%
1319
16th to endNight
17%5%345%345%6%9%34%
1332
June1st to 15thNight
16%42442446%8%41%
1155
16th to endNight
11%315%31346%10%47%
991
July1st to 15thNight
6%2144245%6%8%53%
1201
16th to endNight
421442345%7%59%
1400
August1st to 15thNight
6%224434348%54%
1320
16th to endNight
7%21432345%8%57%
1625
September1st to 15thNight
10%5%235%23446%50%
1650
16th to endNight
13%424413446%51%
1785
October1st to 15thNight
14%8%34423246%44%
1966
16th to endNight
10%10%45%5%2446%7%38%
2280
November1st to 15thNight
11%9%37%6%3435%7%38%
2365
16th to endNight
9%11%5%9%6%35%5%5%7%30%
2619
December1st to 15thNight
9%13%7%13%9%45%5%5%5%18%
2700
16th to endNight
8%12%7%12%9%445%6%7%22%
2870

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
57%7%13%18%3
1433
16th to endDay
58%8%15%12%4
1536
February1st to 15thDay
66%5%11%12%3
1473
16th to endDay
66%6%11%9%5%
1528
March1st to 15thDay
59%8%15%13%2
1800
16th to endDay
53%9%17%16%3
2211
April1st to 15thDay
46%7%17%20%6%
2045
16th to endDay
46%6%18%18%8%
2167
May1st to 15thDay
44%6%13%25%10%
2301
16th to endDay
51%7%14%18%7%
2432
June1st to 15thDay
47%8%17%19%6%
2475
16th to endDay
38%9%22%22%6%
2634
July1st to 15thDay
30%8%19%29%10%1
2273
16th to endDay
28%10%17%30%11%1
2293
August1st to 15thDay
34%7%19%26%9%1
2294
16th to endDay
32%5%14%33%12%1
2222
September1st to 15thDay
36%6%15%27%13%
1980
16th to endDay
36%412%31%13%1
1844
October1st to 15thDay
46%5%14%26%7%
1658
16th to endDay
48%6%19%19%5%
1584
November1st to 15thDay
49%5%15%19%7%1
1493
16th to endDay
57%7%16%11%6%
1340
December1st to 15thDay
70%7%9%10%2
1260
16th to endDay
63%7%14%12%2
1353
January1st to 15thNight
55%7%14%17%4
2506
16th to endNight
56%7%16%13%4
2688
February1st to 15thNight
60%5%13%14%6%
2399
16th to endNight
56%5%14%17%6%
1945
March1st to 15thNight
51%6%17%20%4
2160
16th to endNight
54%6%16%17%3
2009
April1st to 15thNight
41%6%15%24%11%1
1718
16th to endNight
47%6%13%20%9%1
1463
May1st to 15thNight
42%414%23%14%
1320
16th to endNight
45%8%13%19%12%
1333
June1st to 15thNight
39%7%18%23%9%1
1155
16th to endNight
31%7%22%29%8%
991
July1st to 15thNight
25%8%17%35%10%1
1123
16th to endNight
24%7%15%36%14%1
1304
August1st to 15thNight
26%7%18%32%12%1
1312
16th to endNight
23%414%33%20%3
1625
September1st to 15thNight
33%5%13%27%19%1
1650
16th to endNight
33%412%30%18%1
1785
October1st to 15thNight
41%315%26%12%
1966
16th to endNight
43%5%18%24%6%1
2280
November1st to 15thNight
45%6%17%18%10%1
2365
16th to endNight
52%7%17%17%4
2619
December1st to 15thNight
66%6%14%11%2
2700
16th to endNight
59%7%13%14%4
2870

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
10%5%17%38%26%1
90
16th to endDay
12%11%25%35%13%2
96
February1st to 15thDay
16%340%26%13%
90
16th to endDay
16%330%27%20%1
81
March1st to 15thDay
18%11%42%21%6%
90
16th to endDay
17%11%34%25%10%1
258
April1st to 15thDay
15%12%38%25%7%
234
16th to endDay
17%8%30%28%13%
345
May1st to 15thDay
18%9%26%28%14%2
393
16th to endDay
21%8%25%22%17%4
437
June1st to 15thDay
16%6%33%25%15%1
420
16th to endDay
11%7%27%32%17%3
420
July1st to 15thDay
9%425%33%22%5%
400
16th to endDay
5%5%28%37%18%5%
445
August1st to 15thDay
10%423%37%20%3
418
16th to endDay
10%5%20%32%23%7%
336
September1st to 15thDay
17%7%30%23%18%1
255
16th to endDay
18%5%23%32%14%5%
119
October1st to 15thDay
26%5%34%21%10%2
90
16th to endDay
19%12%23%23%14%5%
96
November1st to 15thDay
12%6%33%26%18%2
90
16th to endDay
15%20%24%23%13%3
90
December1st to 15thDay
22%5%30%23%14%4
90
16th to endDay
16%5%43%26%44
96
January1st to 15thNight
12%8%34%31%11%1
900
16th to endNight
12%12%35%30%7%
960
February1st to 15thNight
14%7%29%33%13%1
815
16th to endNight
10%428%37%16%3
632
March1st to 15thNight
11%7%32%32%14%2
720
16th to endNight
16%8%28%31%14%
638
April1st to 15thNight
12%7%35%32%11%
515
16th to endNight
19%8%31%30%9%
495
May1st to 15thNight
17%329%36%11%1
495
16th to endNight
19%6%23%32%16%
515
June1st to 15thNight
18%427%35%13%
495
16th to endNight
13%228%37%18%
331
July1st to 15thNight
8%129%41%18%
405
16th to endNight
4225%48%17%1
522
August1st to 15thNight
8%122%46%19%1
494
16th to endNight
8%321%44%20%1
525
September1st to 15thNight
13%324%34%22%1
495
16th to endNight
13%427%37%15%1
492
October1st to 15thNight
18%6%27%30%14%2
646
16th to endNight
15%7%27%38%11%
872
November1st to 15thNight
15%8%33%30%10%2
875
16th to endNight
14%9%35%31%8%
900
December1st to 15thNight
15%8%31%29%13%2
900
16th to endNight
13%6%30%32%13%3
960
Page generated at 2017-04-08 03:35:15. Version ac04

Copyright 2017 A. Danko


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