Maple Creek
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Maple Creek clear sky chart from 2005-11-05 to 2017-11-30.

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
37%
15811
14%
47702
8%
15779
42%
15779
22%
31871

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
24%
896
11%
2685
6%
895
29%
895
15%
1975
January16th to endNight
25%
918
14%
2802
6%
918
34%
918
16%
1984
February1st to 15thNight
36%
700
11%
2288
9%
696
40%
696
18%
1598
February16th to endNight
32%
632
11%
2052
7%
632
38%
632
16%
1485
March1st to 15thNight
31%
720
12%
2051
6%
720
36%
720
21%
1433
March16th to endNight
30%
762
11%
2106
4%
762
36%
762
18%
1545
April1st to 15thNight
32%
539
12%
1742
7%
539
38%
539
19%
1179
April16th to endNight
39%
540
14%
1614
10%
540
42%
540
21%
1116
May1st to 15thNight
45%
539
14%
1440
9%
539
47%
539
29%
939
May16th to endNight
41%
439
8%
1375
6%
438
43%
438
19%
968
June1st to 15thNight
44%
360
4%
1260
4%
360
45%
360
20%
806
June16th to endNight
52%
360
5%
1260
4%
360
54%
360
28%
717
July1st to 15thNight
60%
340
6%
1190
5%
340
62%
340
36%
613
July16th to endNight
62%
394
17%
1256
15%
371
68%
371
45%
599
August1st to 15thNight
65%
539
15%
1537
12%
536
68%
536
40%
897
August16th to endNight
61%
573
25%
1719
19%
573
65%
573
40%
947
September1st to 15thNight
53%
540
18%
1797
18%
540
56%
540
30%
1038
September16th to endNight
50%
702
24%
1990
16%
702
58%
702
37%
1179
October1st to 15thNight
38%
720
18%
2160
9%
720
46%
720
24%
1394
October16th to endNight
34%
813
18%
2426
8%
813
43%
813
24%
1584
November1st to 15thNight
26%
950
16%
2660
7%
950
35%
950
22%
1811
November16th to endNight
24%
975
14%
2730
6%
975
31%
975
20%
1935
December1st to 15thNight
24%
900
9%
2682
4%
900
28%
900
14%
2069
December16th to endNight
25%
960
13%
2880
5%
960
33%
960
17%
2060

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
10%7%35%5%3445%7%39%
48749
Night
8%8%36%5%345%5%7%39%
47850
Cloud CoverDay
10%7%35%5%35%45%7%39%
48750
Night
9%8%36%5%3445%7%39%
47852
TransparencyDay
42%8%16%22%9%1
48402
Night
42%7%16%21%10%1
47702
SeeingDay
14%8%28%28%16%3
6328
Night
13%9%33%30%12%1
15820

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
9%11%5%8%7%36%45%432%
1253
16th to endDay
310%5%9%10%5%7%5%5%8%28%
1431
February1st to 15thDay
8%11%6%8%7%37%445%32%
1575
16th to endDay
7%12%6%11%8%345%5%5%28%
1422
March1st to 15thDay
48%48%9%45%6%7%8%33%
1908
16th to endDay
9%12%48%6%45%5%6%8%26%
2117
April1st to 15thDay
10%9%35%6%46%5%7%8%32%
2205
16th to endDay
14%10%46%43445%7%34%
2346
May1st to 15thDay
13%7%26%6%35%45%7%38%
2511
16th to endDay
21%8%35%5%35%45%7%29%
2738
June1st to 15thDay
17%6%35%5%35%5%6%7%33%
2700
16th to endDay
11%424436%5%6%8%42%
2700
July1st to 15thDay
6%313435%5%7%9%50%
2700
16th to endDay
6%31232336%8%57%
2828
August1st to 15thDay
8%3244245%7%8%49%
2414
16th to endDay
8%33222349%59%
2483
September1st to 15thDay
13%6%1333344451%
2163
16th to endDay
12%31232335%8%52%
1967
October1st to 15thDay
13%8%35%42346%7%41%
1800
16th to endDay
8%9%2443446%8%42%
1785
November1st to 15thDay
8%11%35%6%3446%8%36%
1528
16th to endDay
7%11%5%8%6%36%5%5%7%32%
1556
December1st to 15thDay
8%13%5%11%6%46%446%26%
1275
16th to endDay
413%5%11%7%35%35%6%30%
1344
January1st to 15thNight
8%11%5%8%6%445%5%8%31%
2685
16th to endNight
6%10%49%7%35%5%6%7%33%
2802
February1st to 15thNight
6%10%47%6%46%5%5%7%33%
2277
16th to endNight
5%12%6%10%6%35%5%6%6%30%
2052
March1st to 15thNight
6%7%38%6%346%7%9%34%
2051
16th to endNight
8%11%48%6%3446%9%31%
2103
April1st to 15thNight
12%8%26%5%345%6%7%35%
1742
16th to endNight
12%8%35%4446%48%36%
1614
May1st to 15thNight
13%5%2442447%7%42%
1439
16th to endNight
18%6%345%35%45%5%35%
1375
June1st to 15thNight
15%426%4345%6%7%40%
1260
16th to endNight
9%223435%5%6%8%48%
1260
July1st to 15thNight
6%31331445%7%57%
1260
16th to endNight
41112235%6%8%61%
1341
August1st to 15thNight
7%31433445%7%55%
1545
16th to endNight
8%31322445%8%56%
1719
September1st to 15thNight
12%5%13324445%52%
1797
16th to endNight
9%4134245%5%7%52%
1990
October1st to 15thNight
12%7%25%4245%5%7%42%
2160
16th to endNight
9%9%35%5%3445%7%41%
2426
November1st to 15thNight
8%10%35%5%2445%7%40%
2660
16th to endNight
6%12%5%7%6%3445%7%36%
2730
December1st to 15thNight
6%14%7%9%9%45%447%27%
2682
16th to endNight
6%10%410%7%35%5%48%33%
2880

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
10%12%48%7%46%44432%
1253
16th to endDay
310%49%10%5%6%5%5%8%28%
1431
February1st to 15thDay
9%12%5%8%6%46%445%32%
1575
16th to endDay
8%13%5%11%8%445%5%5%29%
1422
March1st to 15thDay
49%47%8%46%5%6%8%33%
1908
16th to endDay
9%13%48%6%45%5%6%8%27%
2118
April1st to 15thDay
10%9%345%35%6%7%8%33%
2205
16th to endDay
15%10%46%424447%34%
2346
May1st to 15thDay
14%7%25%5%35%45%8%38%
2511
16th to endDay
22%8%25%5%35%45%6%29%
2738
June1st to 15thDay
18%6%245%26%5%6%7%33%
2700
16th to endDay
12%413426%6%6%9%43%
2700
July1st to 15thDay
7%313435%5%6%10%50%
2700
16th to endDay
6%21232336%8%57%
2828
August1st to 15thDay
8%3144235%6%7%50%
2414
16th to endDay
8%312213348%59%
2483
September1st to 15thDay
13%6%1332343451%
2163
16th to endDay
12%31322335%8%53%
1967
October1st to 15thDay
13%8%35%42345%7%41%
1800
16th to endDay
9%9%2433446%8%42%
1785
November1st to 15thDay
9%10%36%6%345%6%7%36%
1528
16th to endDay
7%11%5%8%6%37%45%7%31%
1556
December1st to 15thDay
8%13%5%12%6%46%5%47%25%
1275
16th to endDay
5%13%5%11%8%35%447%30%
1344
January1st to 15thNight
8%11%48%6%45%6%48%30%
2685
16th to endNight
7%10%49%7%346%5%8%33%
2802
February1st to 15thNight
7%10%37%7%46%5%5%7%34%
2277
16th to endNight
5%12%6%10%6%35%6%6%6%30%
2052
March1st to 15thNight
6%7%38%6%35%6%7%9%35%
2051
16th to endNight
8%11%48%5%35%46%9%31%
2106
April1st to 15thNight
12%8%26%6%335%6%7%36%
1742
16th to endNight
13%7%35%435%5%6%8%36%
1614
May1st to 15thNight
13%42442446%8%41%
1439
16th to endNight
19%5%245%35%5%5%5%36%
1374
June1st to 15thNight
15%425%43447%7%40%
1260
16th to endNight
9%223335%5%6%8%48%
1260
July1st to 15thNight
6%32222436%7%57%
1260
16th to endNight
41221346%8%62%
1341
August1st to 15thNight
7%31342445%8%54%
1545
16th to endNight
8%31322345%7%56%
1719
September1st to 15thNight
13%41332444452%
1797
16th to endNight
9%31332446%7%52%
1990
October1st to 15thNight
12%6%2442445%7%43%
2160
16th to endNight
10%9%25%5%34447%41%
2426
November1st to 15thNight
9%10%35%5%34447%40%
2660
16th to endNight
7%12%5%8%5%3445%7%36%
2730
December1st to 15thNight
7%13%6%10%8%35%35%6%27%
2682
16th to endNight
6%10%5%10%7%36%447%33%
2880

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
55%8%12%18%4
1253
16th to endDay
53%8%16%16%41
1431
February1st to 15thDay
53%7%14%18%5%
1575
16th to endDay
56%8%14%13%6%1
1422
March1st to 15thDay
46%10%20%16%4
1908
16th to endDay
54%9%16%16%3
2118
April1st to 15thDay
47%9%16%18%7%
2205
16th to endDay
49%7%15%20%5%1
2346
May1st to 15thDay
45%7%15%23%9%
2511
16th to endDay
54%7%13%16%6%
2743
June1st to 15thDay
49%8%15%19%7%
2700
16th to endDay
35%9%20%26%7%
2700
July1st to 15thDay
27%9%19%27%14%1
2541
16th to endDay
23%7%16%31%18%2
2650
August1st to 15thDay
31%8%18%25%13%2
2398
16th to endDay
24%5%14%32%19%3
2483
September1st to 15thDay
36%5%11%24%17%4
2163
16th to endDay
30%6%14%30%16%1
1967
October1st to 15thDay
42%6%18%23%8%
1800
16th to endDay
38%7%19%24%8%
1785
November1st to 15thDay
46%7%19%20%5%
1528
16th to endDay
50%7%18%16%6%
1556
December1st to 15thDay
58%8%15%15%2
1275
16th to endDay
53%8%16%17%4
1344
January1st to 15thNight
51%8%18%16%31
2685
16th to endNight
48%8%16%18%6%1
2802
February1st to 15thNight
48%7%17%17%7%1
2288
16th to endNight
52%6%14%17%7%
2052
March1st to 15thNight
42%10%21%17%7%
2051
16th to endNight
48%9%15%20%5%
2106
April1st to 15thNight
45%7%15%20%9%
1742
16th to endNight
45%7%13%20%9%3
1614
May1st to 15thNight
38%6%12%27%14%1
1440
16th to endNight
48%7%15%16%12%
1375
June1st to 15thNight
41%8%15%24%9%
1260
16th to endNight
32%7%18%28%12%
1260
July1st to 15thNight
25%6%16%29%19%2
1190
16th to endNight
17%7%15%29%24%5%
1256
August1st to 15thNight
27%7%15%31%14%2
1537
16th to endNight
26%5%11%25%25%5%
1719
September1st to 15thNight
33%6%10%23%16%9%
1797
16th to endNight
29%6%13%27%19%3
1990
October1st to 15thNight
39%7%16%23%12%
2160
16th to endNight
40%7%17%23%9%
2426
November1st to 15thNight
43%7%17%21%9%1
2660
16th to endNight
47%6%20%16%7%
2730
December1st to 15thNight
58%7%16%13%4
2682
16th to endNight
49%7%15%20%5%
2880

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
16%126%23%18%13%
60
16th to endDay
48%40%28%17%1
70
February1st to 15thDay
22%13%33%23%6%1
90
16th to endDay
24%6%30%29%7%1
81
March1st to 15thDay
12%15%45%20%6%
228
16th to endDay
14%14%39%24%6%
288
April1st to 15thDay
13%20%36%22%5%1
269
16th to endDay
26%9%26%25%10%1
276
May1st to 15thDay
14%5%29%29%16%4
468
16th to endDay
24%6%22%24%16%5%
517
June1st to 15thDay
17%8%28%27%16%2
495
16th to endDay
12%7%30%26%18%3
495
July1st to 15thDay
8%321%38%25%2
475
16th to endDay
8%5%26%32%22%3
515
August1st to 15thDay
8%324%31%25%6%
389
16th to endDay
9%419%35%26%4
332
September1st to 15thDay
19%325%30%16%5%
315
16th to endDay
14%7%24%31%15%7%
290
October1st to 15thDay
26%8%25%27%9%1
135
16th to endDay
17%11%29%25%15%
144
November1st to 15thDay
15%7%39%26%10%
135
16th to endDay
14%15%44%11%11%2
134
December1st to 15thDay
14%11%33%25%11%4
63
16th to endDay
14%14%39%21%7%3
64
January1st to 15thNight
14%15%37%22%8%1
900
16th to endNight
12%14%38%23%9%1
918
February1st to 15thNight
12%10%32%29%13%2
704
16th to endNight
11%9%31%33%12%1
632
March1st to 15thNight
10%9%42%26%10%1
720
16th to endNight
13%11%34%29%8%1
762
April1st to 15thNight
17%8%35%29%8%
539
16th to endNight
18%6%29%30%14%
540
May1st to 15thNight
16%426%36%15%
540
16th to endNight
20%7%23%28%17%2
439
June1st to 15thNight
18%428%30%16%1
360
16th to endNight
11%6%24%39%17%1
360
July1st to 15thNight
9%322%47%15%
340
16th to endNight
6%228%39%22%1
394
August1st to 15thNight
9%318%39%27%2
539
16th to endNight
9%421%41%22%1
573
September1st to 15thNight
14%323%36%20%1
540
16th to endNight
10%5%30%35%15%3
702
October1st to 15thNight
15%8%32%29%12%1
720
16th to endNight
16%10%32%31%8%
813
November1st to 15thNight
16%12%39%23%7%
950
16th to endNight
11%12%44%25%6%
975
December1st to 15thNight
12%10%39%26%9%1
900
16th to endNight
11%10%39%26%10%2
960
Page generated at 2017-12-01 11:13:48. Version ac04

Copyright 2017 A. Danko


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