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 2017-12-02.

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
39%
16388
13%
47578
8%
16349
43%
16349
22%
32863

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
32%
895
15%
1910
January16th to endNight
25%
960
10%
2688
5%
960
30%
960
14%
2083
February1st to 15thNight
30%
810
8%
2399
4%
810
34%
810
13%
1867
February16th to endNight
37%
632
13%
1945
10%
632
41%
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%
539
16%
1798
13%
539
45%
539
24%
1136
April16th to endNight
35%
540
15%
1596
10%
540
40%
540
21%
1109
May1st to 15thNight
43%
540
13%
1440
7%
540
45%
540
29%
950
May16th to endNight
43%
563
9%
1457
5%
561
45%
561
25%
1030
June1st to 15thNight
44%
540
4%
1260
1%
540
46%
540
32%
867
June16th to endNight
50%
361
6%
1081
7%
361
53%
361
33%
643
July1st to 15thNight
57%
445
8%
1233
6%
445
59%
445
42%
709
July16th to endNight
60%
564
16%
1416
9%
531
63%
531
46%
800
August1st to 15thNight
63%
539
18%
1432
11%
536
67%
536
40%
857
August16th to endNight
61%
573
25%
1774
20%
573
68%
573
45%
902
September1st to 15thNight
54%
540
19%
1800
18%
540
60%
540
33%
1011
September16th to endNight
50%
537
24%
1948
23%
537
57%
537
28%
1092
October1st to 15thNight
41%
705
19%
2145
11%
705
48%
705
27%
1348
October16th to endNight
40%
951
19%
2487
10%
951
45%
951
28%
1687
November1st to 15thNight
33%
950
15%
2568
6%
950
39%
950
22%
1822
November16th to endNight
30%
975
13%
2837
7%
975
36%
975
17%
2073
December1st to 15thNight
27%
910
6%
2729
4%
910
29%
910
10%
2219
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%36%
48868
Night
9%8%47%6%35%45%7%36%
47742
Cloud CoverDay
11%8%36%6%35%5%5%7%36%
48878
Night
9%9%47%6%3445%7%36%
47745
Cloud CoverDay
11%8%36%6%35%5%5%7%36%
48878
Night
9%8%47%6%3445%7%36%
47747
TransparencyDay
46%7%15%21%8%
48550
Night
46%6%15%21%9%
47578
SeeingDay
14%7%28%29%16%3
6475
Night
13%6%30%34%13%1
16397

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
10%8%36%6%35%5%5%7%36%
2150
16th to endDay
15%10%26%5%345%5%7%34%
2364
May1st to 15thDay
13%9%26%5%2345%7%39%
2511
16th to endDay
20%6%26%5%245%5%8%31%
2655
June1st to 15thDay
16%5%25%5%36%5%6%7%35%
2700
16th to endDay
12%424435%5%7%10%39%
2874
July1st to 15thDay
7%3235%345%5%8%51%
2643
16th to endDay
5%313335%6%6%8%51%
2656
August1st to 15thDay
10%314435%5%6%8%45%
2520
16th to endDay
9%423424347%53%
2425
September1st to 15thDay
13%5%14323447%49%
2160
16th to endDay
13%5%25%423346%48%
2011
October1st to 15thDay
16%8%36%32335%6%39%
1809
16th to endDay
12%11%46%42345%7%37%
1728
November1st to 15thDay
9%10%5%8%7%45%446%34%
1620
16th to endDay
9%14%5%8%7%5%5%447%28%
1451
December1st to 15thDay
10%16%8%11%11%5%6%5%5%6%12%
1268
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
9%8%46%4245%5%7%41%
1798
16th to endNight
15%10%37%4235%6%6%35%
1596
May1st to 15thNight
13%6%35%335%36%6%42%
1440
16th to endNight
15%5%25%5%3446%8%36%
1456
June1st to 15thNight
15%42442446%8%41%
1260
16th to endNight
11%31441346%11%47%
1081
July1st to 15thNight
6%2134245%5%8%54%
1311
16th to endNight
421441435%7%61%
1512
August1st to 15thNight
6%223434448%54%
1440
16th to endNight
6%21422345%8%59%
1774
September1st to 15thNight
10%5%145%23346%52%
1800
16th to endNight
13%424423446%50%
1948
October1st to 15thNight
13%8%24423346%45%
2145
16th to endNight
10%10%35%5%2436%7%39%
2487
November1st to 15thNight
10%10%37%6%3445%7%36%
2568
16th to endNight
9%10%5%9%6%45%45%7%30%
2837
December1st to 15thNight
9%13%7%13%9%45%45%5%18%
2729
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
10%8%36%6%35%5%6%8%35%
2150
16th to endDay
15%10%26%5%245%5%7%34%
2364
May1st to 15thDay
13%9%35%5%2445%8%38%
2511
16th to endDay
20%6%35%5%25%46%8%31%
2655
June1st to 15thDay
16%5%26%5%35%5%6%8%35%
2700
16th to endDay
12%4245%25%5%6%10%40%
2874
July1st to 15thDay
7%3135%35%5%5%9%51%
2643
16th to endDay
5%323435%5%7%9%51%
2656
August1st to 15thDay
9%414435%5%6%9%44%
2520
16th to endDay
9%324423447%53%
2425
September1st to 15thDay
13%5%14423347%48%
2160
16th to endDay
12%6%15%423437%48%
2011
October1st to 15thDay
15%9%35%32335%7%39%
1809
16th to endDay
12%11%46%42446%6%37%
1728
November1st to 15thDay
9%10%5%8%6%45%446%34%
1620
16th to endDay
9%13%5%8%6%45%447%29%
1451
December1st to 15thDay
10%16%8%11%11%46%6%5%6%13%
1268
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
9%8%36%4245%6%7%41%
1798
16th to endNight
15%9%46%5%2445%6%35%
1596
May1st to 15thNight
12%7%25%42445%7%42%
1439
16th to endNight
15%6%245%3445%9%36%
1457
June1st to 15thNight
14%4344235%6%8%42%
1260
16th to endNight
11%32441346%9%47%
1081
July1st to 15thNight
5%2143345%5%8%55%
1311
16th to endNight
421342335%6%60%
1512
August1st to 15thNight
6%32433346%7%54%
1440
16th to endNight
6%21331335%8%59%
1774
September1st to 15thNight
10%5%24423346%52%
1800
16th to endNight
13%414424346%50%
1948
October1st to 15thNight
13%9%24423346%45%
2145
16th to endNight
9%10%45%5%2345%7%39%
2487
November1st to 15thNight
10%10%37%7%3435%6%36%
2568
16th to endNight
8%10%5%9%6%35%45%7%31%
2837
December1st to 15thNight
9%13%7%13%9%5%5%5%5%5%19%
2729
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
10%8%36%6%35%5%5%7%36%
2150
16th to endDay
15%10%26%5%345%5%7%34%
2364
May1st to 15thDay
13%8%35%5%2345%7%39%
2511
16th to endDay
20%6%26%5%245%5%8%31%
2655
June1st to 15thDay
16%5%26%5%36%5%6%8%35%
2700
16th to endDay
12%4245%35%5%6%9%40%
2874
July1st to 15thDay
6%3135%35%5%5%8%50%
2643
16th to endDay
5%313335%6%6%8%51%
2656
August1st to 15thDay
9%4145%35%5%6%8%45%
2520
16th to endDay
9%423424347%53%
2425
September1st to 15thDay
13%5%14423446%49%
2160
16th to endDay
13%5%25%423346%48%
2011
October1st to 15thDay
16%9%35%32335%6%39%
1809
16th to endDay
12%11%46%42345%6%37%
1728
November1st to 15thDay
9%10%5%8%7%45%446%34%
1620
16th to endDay
9%14%48%6%5%5%35%7%28%
1451
December1st to 15thDay
10%16%8%11%11%5%6%46%6%12%
1268
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
9%8%46%4245%5%7%41%
1798
16th to endNight
14%10%37%4235%5%6%35%
1596
May1st to 15thNight
12%6%25%33435%7%42%
1439
16th to endNight
15%5%25%5%345%6%9%36%
1456
June1st to 15thNight
15%4244245%6%8%42%
1260
16th to endNight
11%315%41346%10%47%
1081
July1st to 15thNight
6%2133245%5%8%54%
1311
16th to endNight
421442435%7%60%
1512
August1st to 15thNight
6%22443435%8%54%
1440
16th to endNight
6%21432345%8%59%
1774
September1st to 15thNight
10%5%235%23446%52%
1800
16th to endNight
13%424424446%50%
1948
October1st to 15thNight
13%8%24423346%45%
2145
16th to endNight
10%10%35%5%2436%7%39%
2487
November1st to 15thNight
10%10%37%6%34347%36%
2568
16th to endNight
9%10%5%9%6%45%5%5%7%30%
2837
December1st to 15thNight
9%13%7%13%9%45%5%5%5%18%
2729
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
45%7%17%21%6%
2150
16th to endDay
47%6%17%19%7%
2364
May1st to 15thDay
43%6%13%25%10%
2511
16th to endDay
49%7%13%18%9%
2659
June1st to 15thDay
46%8%16%20%7%
2700
16th to endDay
38%8%21%23%7%
2874
July1st to 15thDay
29%8%19%30%11%1
2493
16th to endDay
27%9%16%30%14%1
2489
August1st to 15thDay
34%8%19%26%8%1
2504
16th to endDay
30%5%14%35%12%1
2425
September1st to 15thDay
35%5%14%28%14%1
2160
16th to endDay
38%412%30%12%1
2011
October1st to 15thDay
44%5%14%26%9%
1809
16th to endDay
46%6%19%20%6%
1728
November1st to 15thDay
51%5%14%19%7%1
1620
16th to endDay
55%7%18%11%6%
1451
December1st to 15thDay
70%7%9%10%2
1268
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
40%6%15%24%11%1
1798
16th to endNight
48%6%13%21%9%1
1596
May1st to 15thNight
40%5%14%24%15%
1440
16th to endNight
44%8%13%19%13%1
1457
June1st to 15thNight
38%7%18%23%9%2
1260
16th to endNight
31%7%21%29%8%
1081
July1st to 15thNight
24%8%18%35%12%1
1233
16th to endNight
22%6%15%35%16%2
1416
August1st to 15thNight
27%7%17%32%12%1
1432
16th to endNight
22%415%33%21%2
1774
September1st to 15thNight
31%5%12%27%21%2
1800
16th to endNight
34%412%29%17%1
1948
October1st to 15thNight
40%415%27%12%
2145
16th to endNight
42%5%18%24%7%1
2487
November1st to 15thNight
47%6%16%17%9%1
2568
16th to endNight
51%7%18%17%4
2837
December1st to 15thNight
65%6%13%11%2
2729
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
14%14%39%24%7%
269
16th to endDay
19%7%29%27%14%1
417
May1st to 15thDay
16%9%28%27%14%2
468
16th to endDay
19%7%26%24%17%4
517
June1st to 15thDay
15%8%33%25%16%1
495
16th to endDay
11%8%27%33%16%3
495
July1st to 15thDay
8%325%35%22%4
475
16th to endDay
46%27%37%19%4
515
August1st to 15thDay
10%420%35%20%7%
493
16th to endDay
8%419%33%25%8%
406
September1st to 15thDay
17%9%27%25%17%2
315
16th to endDay
21%421%31%16%3
166
October1st to 15thDay
20%7%33%25%11%1
135
16th to endDay
17%12%29%26%11%3
144
November1st to 15thDay
13%5%34%27%17%2
135
16th to endDay
13%17%28%30%8%2
135
December1st to 15thDay
21%5%28%24%14%5%
94
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
11%7%36%33%10%
539
16th to endNight
20%7%30%30%9%
540
May1st to 15thNight
16%330%35%12%1
540
16th to endNight
19%6%24%32%16%1
563
June1st to 15thNight
18%329%35%13%
540
16th to endNight
12%229%38%17%
361
July1st to 15thNight
8%128%42%17%
445
16th to endNight
4226%48%17%1
564
August1st to 15thNight
8%120%45%21%2
539
16th to endNight
8%321%44%21%1
573
September1st to 15thNight
12%325%34%22%1
540
16th to endNight
13%427%37%15%1
537
October1st to 15thNight
18%7%27%30%14%1
705
16th to endNight
15%7%27%37%10%
951
November1st to 15thNight
16%7%33%30%9%2
950
16th to endNight
14%9%36%31%7%
975
December1st to 15thNight
15%8%31%29%13%2
910
16th to endNight
13%6%30%32%13%3
960
Page generated at 2017-12-03 10:16:36. Version ac04

Copyright 2017 A. Danko


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