Shaunavon
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shaunavon clear sky chart from 2005-11-05 to 2017-10-06.

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%
15640
15%
46951
9%
15604
44%
15604
23%
31098

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
23%
895
12%
2685
6%
895
29%
895
16%
1939
January16th to endNight
23%
942
16%
2776
6%
942
34%
942
17%
1957
February1st to 15thNight
35%
700
12%
2288
9%
696
40%
696
18%
1578
February16th to endNight
33%
632
12%
2052
8%
632
39%
632
15%
1512
March1st to 15thNight
31%
720
13%
2053
6%
720
38%
720
22%
1452
March16th to endNight
31%
738
12%
2082
5%
738
37%
738
17%
1547
April1st to 15thNight
39%
539
15%
1777
9%
539
45%
539
22%
1157
April16th to endNight
38%
540
14%
1590
11%
540
42%
540
21%
1114
May1st to 15thNight
46%
539
13%
1440
8%
539
49%
539
30%
951
May16th to endNight
39%
491
8%
1426
5%
489
41%
489
20%
1021
June1st to 15thNight
44%
360
5%
1260
4%
360
47%
360
21%
805
June16th to endNight
50%
360
6%
1260
5%
360
53%
360
30%
704
July1st to 15thNight
58%
340
7%
1190
6%
340
61%
340
35%
626
July16th to endNight
64%
438
18%
1296
14%
411
69%
411
48%
626
August1st to 15thNight
61%
539
17%
1507
12%
536
65%
536
42%
857
August16th to endNight
62%
573
26%
1743
21%
573
66%
573
41%
946
September1st to 15thNight
57%
540
19%
1800
19%
540
60%
540
32%
1032
September16th to endNight
53%
668
26%
1980
20%
668
61%
668
38%
1113
October1st to 15thNight
38%
684
21%
2052
11%
684
47%
684
27%
1275
October16th to endNight
36%
767
19%
2213
9%
767
45%
767
25%
1447
November1st to 15thNight
29%
875
19%
2450
8%
875
38%
875
24%
1607
November16th to endNight
27%
900
14%
2520
6%
900
35%
900
21%
1761
December1st to 15thNight
25%
900
10%
2631
4%
900
29%
900
14%
2020
December16th to endNight
26%
960
14%
2880
5%
960
34%
960
16%
2051

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
9%7%36%5%35%5%6%7%38%
48279
Night
7%7%36%6%35%5%6%8%39%
47103
Cloud CoverDay
10%7%36%5%35%45%7%38%
48280
Night
7%7%36%6%35%5%6%8%39%
47105
TransparencyDay
43%7%15%22%9%1
47935
Night
41%7%15%22%10%1
46951
SeeingDay
14%8%28%28%16%3
6178
Night
11%8%33%31%12%1
15650

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
7%10%49%7%6%5%7%6%6%29%
1253
16th to endDay
27%49%10%5%7%8%7%8%28%
1455
February1st to 15thDay
7%10%48%7%46%5%5%7%31%
1575
16th to endDay
5%10%6%11%9%47%5%6%6%25%
1422
March1st to 15thDay
47%5%10%7%46%6%7%8%32%
1903
16th to endDay
10%10%5%11%6%45%5%5%8%24%
2140
April1st to 15thDay
10%8%46%6%46%5%7%8%31%
2170
16th to endDay
15%10%36%5%2435%7%33%
2370
May1st to 15thDay
12%8%35%5%35%45%7%37%
2511
16th to endDay
21%8%37%5%35%45%6%28%
2687
June1st to 15thDay
16%6%35%6%345%5%8%32%
2700
16th to endDay
10%5%25%4245%6%9%43%
2700
July1st to 15thDay
5%315%42446%10%51%
2700
16th to endDay
331331345%9%57%
2780
August1st to 15thDay
7%325%5%245%7%7%48%
2443
16th to endDay
7%413323347%58%
2459
September1st to 15thDay
12%6%24424345%50%
2160
16th to endDay
12%41422446%6%49%
1977
October1st to 15thDay
10%9%36%423347%42%
1705
16th to endDay
6%10%35%5%245%6%9%38%
1648
November1st to 15thDay
5%9%46%435%5%7%7%40%
1408
16th to endDay
8%9%5%7%7%45%45%8%33%
1440
December1st to 15thDay
5%12%413%8%5%6%47%8%22%
1329
16th to endDay
5%9%5%10%9%47%46%7%29%
1344
January1st to 15thNight
49%5%7%7%46%7%6%8%31%
2685
16th to endNight
37%49%7%46%5%8%9%33%
2776
February1st to 15thNight
5%7%48%7%36%6%6%9%33%
2277
16th to endNight
310%6%11%7%36%5%7%8%27%
2052
March1st to 15thNight
5%6%48%7%47%5%6%9%35%
2053
16th to endNight
8%10%6%8%5%45%5%7%8%28%
2079
April1st to 15thNight
10%7%36%5%35%5%5%7%40%
1777
16th to endNight
12%9%36%5%45%5%5%5%35%
1590
May1st to 15thNight
9%7%35%5%3446%8%42%
1439
16th to endNight
17%6%36%6%3435%6%35%
1426
June1st to 15thNight
14%6%245%35%35%6%42%
1260
16th to endNight
6%325%5%2436%10%49%
1260
July1st to 15thNight
42134345%48%55%
1260
16th to endNight
311232445%8%61%
1385
August1st to 15thNight
6%3134235%5%7%56%
1515
16th to endNight
8%312323347%57%
1743
September1st to 15thNight
9%425%42435%6%52%
1800
16th to endNight
7%4133235%5%8%53%
1980
October1st to 15thNight
10%7%25%424348%45%
2052
16th to endNight
7%8%35%5%245%6%9%41%
2213
November1st to 15thNight
7%6%36%5%35%5%47%43%
2450
16th to endNight
7%9%48%6%35%46%8%35%
2520
December1st to 15thNight
5%9%6%11%9%47%5%7%7%25%
2631
16th to endNight
5%9%48%7%5%6%5%6%9%31%
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
7%10%5%9%7%5%6%6%6%6%28%
1253
16th to endDay
28%5%9%9%5%8%7%7%7%28%
1455
February1st to 15thDay
7%11%39%8%46%5%36%31%
1575
16th to endDay
6%12%413%8%5%6%5%5%7%25%
1422
March1st to 15thDay
47%5%9%8%46%6%7%8%30%
1903
16th to endDay
10%10%6%11%7%45%5%5%8%24%
2141
April1st to 15thDay
10%8%47%5%46%5%7%8%31%
2170
16th to endDay
15%11%36%5%2345%6%33%
2370
May1st to 15thDay
12%8%35%6%3445%6%37%
2511
16th to endDay
22%7%36%6%35%45%6%28%
2687
June1st to 15thDay
17%6%26%5%35%46%8%32%
2700
16th to endDay
11%425%325%46%9%43%
2700
July1st to 15thDay
6%21442446%10%50%
2700
16th to endDay
431342346%8%57%
2780
August1st to 15thDay
7%425%4345%6%7%48%
2443
16th to endDay
8%313323348%57%
2459
September1st to 15thDay
12%6%24433345%49%
2160
16th to endDay
13%42422345%7%48%
1977
October1st to 15thDay
12%9%35%424348%42%
1705
16th to endDay
7%10%45%4245%6%9%38%
1648
November1st to 15thDay
5%11%45%5%25%6%6%7%40%
1408
16th to endDay
8%9%5%8%7%35%449%32%
1440
December1st to 15thDay
6%11%412%9%46%5%6%8%22%
1329
16th to endDay
5%10%5%11%9%36%46%7%28%
1344
January1st to 15thNight
410%6%7%7%46%6%6%8%30%
2685
16th to endNight
38%5%9%7%46%5%8%8%32%
2776
February1st to 15thNight
5%7%48%8%46%6%6%8%33%
2277
16th to endNight
410%7%11%7%45%5%6%8%27%
2052
March1st to 15thNight
47%48%7%45%5%6%9%34%
2053
16th to endNight
9%10%5%8%6%35%5%6%8%28%
2082
April1st to 15thNight
10%7%25%6%345%5%8%39%
1777
16th to endNight
13%10%25%6%4445%6%35%
1590
May1st to 15thNight
10%7%25%435%45%8%41%
1439
16th to endNight
17%5%37%6%335%46%34%
1425
June1st to 15thNight
14%6%24426%35%6%42%
1260
16th to endNight
6%415%43445%10%49%
1260
July1st to 15thNight
42145%34448%55%
1260
16th to endNight
41133235%5%7%62%
1385
August1st to 15thNight
7%21343345%8%55%
1515
16th to endNight
8%313324346%58%
1743
September1st to 15thNight
9%5%24334345%52%
1800
16th to endNight
8%41332346%8%52%
1980
October1st to 15thNight
11%7%3442435%8%45%
2052
16th to endNight
7%8%35%5%245%6%9%40%
2213
November1st to 15thNight
7%8%36%5%35%45%7%43%
2450
16th to endNight
7%9%5%8%6%35%46%9%34%
2520
December1st to 15thNight
5%10%6%11%9%46%6%6%7%24%
2631
16th to endNight
6%10%48%7%47%5%7%9%29%
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
52%10%11%18%5%
1253
16th to endDay
51%8%16%17%41
1455
February1st to 15thDay
52%8%15%16%7%
1575
16th to endDay
57%8%13%12%7%
1422
March1st to 15thDay
47%10%19%17%5%
1903
16th to endDay
55%9%15%17%2
2141
April1st to 15thDay
48%8%16%19%7%
2170
16th to endDay
50%6%13%21%5%1
2370
May1st to 15thDay
45%6%14%25%8%
2511
16th to endDay
54%7%12%17%6%
2691
June1st to 15thDay
48%8%15%19%8%
2700
16th to endDay
35%8%18%28%8%
2700
July1st to 15thDay
27%9%16%30%14%1
2541
16th to endDay
23%7%14%31%19%3
2606
August1st to 15thDay
33%8%16%24%14%2
2427
16th to endDay
26%5%13%31%19%4
2459
September1st to 15thDay
36%5%11%25%17%2
2160
16th to endDay
34%6%11%30%16%1
1977
October1st to 15thDay
41%5%17%26%8%
1705
16th to endDay
41%8%18%25%6%
1648
November1st to 15thDay
40%8%18%25%6%
1408
16th to endDay
48%7%18%16%8%
1440
December1st to 15thDay
57%8%14%17%1
1329
16th to endDay
53%8%17%16%4
1344
January1st to 15thNight
48%9%16%19%41
2685
16th to endNight
45%9%16%20%6%1
2776
February1st to 15thNight
46%8%16%19%7%1
2288
16th to endNight
53%8%12%18%7%
2052
March1st to 15thNight
45%8%17%18%9%
2053
16th to endNight
51%8%14%19%6%
2082
April1st to 15thNight
41%8%14%23%10%
1777
16th to endNight
49%5%11%20%11%2
1590
May1st to 15thNight
38%6%12%28%12%
1440
16th to endNight
49%7%13%18%10%
1426
June1st to 15thNight
41%7%15%22%12%
1260
16th to endNight
30%7%20%30%10%
1260
July1st to 15thNight
26%6%15%27%20%3
1190
16th to endNight
18%5%15%33%22%5%
1296
August1st to 15thNight
26%6%16%33%15%2
1507
16th to endNight
26%49%28%24%6%
1743
September1st to 15thNight
32%5%9%25%18%7%
1800
16th to endNight
27%6%14%30%18%3
1980
October1st to 15thNight
38%5%15%26%13%1
2052
16th to endNight
38%7%15%25%11%
2213
November1st to 15thNight
40%6%17%23%10%1
2450
16th to endNight
46%6%21%17%7%
2520
December1st to 15thNight
55%8%16%15%4
2631
16th to endNight
48%8%15%19%6%
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
10%130%26%23%8%
60
16th to endDay
7%8%35%23%20%3
78
February1st to 15thDay
15%18%40%17%7%
90
16th to endDay
14%437%27%16%
81
March1st to 15thDay
8%15%43%23%9%
198
16th to endDay
16%7%39%25%8%1
288
April1st to 15thDay
15%17%33%25%7%
269
16th to endDay
24%11%24%27%11%1
300
May1st to 15thDay
16%8%24%28%17%4
468
16th to endDay
22%8%26%20%16%5%
517
June1st to 15thDay
15%10%30%24%15%2
495
16th to endDay
13%9%25%30%16%4
495
July1st to 15thDay
7%326%34%22%4
475
16th to endDay
7%426%36%22%2
515
August1st to 15thDay
9%5%23%34%20%6%
417
16th to endDay
9%5%23%37%18%5%
332
September1st to 15thDay
17%5%29%29%14%4
315
16th to endDay
16%7%22%28%18%5%
267
October1st to 15thDay
31%8%29%14%11%3
107
16th to endDay
11%10%28%26%20%3
96
November1st to 15thDay
5%7%46%30%10%
90
16th to endDay
6%18%31%22%15%5%
90
December1st to 15thDay
5%11%43%23%8%7%
71
16th to endDay
10%10%46%25%33
64
January1st to 15thNight
12%15%40%21%9%1
900
16th to endNight
8%17%41%21%9%1
942
February1st to 15thNight
8%9%35%30%13%1
704
16th to endNight
9%9%34%32%12%2
632
March1st to 15thNight
7%8%43%28%11%1
720
16th to endNight
14%8%35%28%10%1
738
April1st to 15thNight
14%5%35%33%10%
539
16th to endNight
19%7%26%33%12%
540
May1st to 15thNight
14%5%27%36%14%2
540
16th to endNight
20%5%23%32%15%2
491
June1st to 15thNight
19%5%26%31%15%1
360
16th to endNight
8%5%31%37%15%1
360
July1st to 15thNight
7%323%46%17%1
340
16th to endNight
5%422%46%19%1
438
August1st to 15thNight
9%323%37%23%3
539
16th to endNight
11%319%40%24%1
573
September1st to 15thNight
13%420%37%21%2
540
16th to endNight
10%5%26%37%17%2
668
October1st to 15thNight
16%5%33%29%12%2
684
16th to endNight
11%10%35%32%8%
767
November1st to 15thNight
12%13%39%25%8%1
875
16th to endNight
12%11%40%28%6%
900
December1st to 15thNight
11%10%38%28%10%
900
16th to endNight
12%10%40%26%9%
960
Page generated at 2017-10-07 12:07:49. Version ac04

Copyright 2017 A. Danko


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