Olds
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Olds clear sky chart from 2005-11-06 to 2024-01-12.

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%
23403
13%
74619
9%
23374
46%
23374
21%
50070

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 10thNight
34%
946
14%
2836
8%
946
39%
946
18%
2061
January11th to 20thNight
35%
910
15%
2730
9%
910
41%
910
20%
1944
January21st to endNight
34%
807
19%
2787
12%
807
44%
807
16%
1918
February1st to 10thNight
36%
720
13%
2520
12%
720
41%
720
15%
1764
February11th to 20thNight
35%
703
13%
2305
9%
700
43%
700
16%
1658
February21st to endNight
44%
592
17%
1821
14%
592
50%
592
22%
1230
March1st to 10thNight
40%
720
15%
2160
12%
720
45%
720
19%
1565
March11th to 20thNight
41%
720
17%
2012
10%
720
46%
720
23%
1408
March21st to endNight
37%
792
11%
2135
5%
792
41%
792
19%
1600
April1st to 10thNight
37%
666
14%
1746
5%
666
43%
666
21%
1270
April11th to 20thNight
34%
533
13%
1601
8%
533
39%
533
18%
1167
April21st to endNight
37%
540
10%
1620
8%
540
40%
540
20%
1144
May1st to 10thNight
36%
423
7%
1444
7%
423
39%
423
18%
985
May11th to 20thNight
46%
354
12%
1239
11%
354
50%
354
23%
782
May21st to endNight
45%
388
4%
1358
2%
388
46%
388
19%
911
June1st to 10thNight
47%
360
0%
1260
0%
360
47%
360
17%
887
June11th to 20thNight
38%
360
0%
1260
0%
360
38%
360
14%
937
June21st to endNight
55%
360
0%
1260
0%
360
55%
360
23%
797
July1st to 10thNight
60%
350
0%
1225
0%
350
60%
350
23%
775
July11th to 20thNight
57%
348
3%
1218
1%
348
57%
348
22%
778
July21st to endNight
65%
394
10%
1335
9%
372
68%
372
32%
727
August1st to 10thNight
60%
358
9%
1424
14%
356
61%
356
22%
870
August11th to 20thNight
62%
482
13%
1550
14%
482
64%
482
29%
924
August21st to endNight
58%
594
18%
1782
14%
594
61%
594
32%
1080
September1st to 10thNight
54%
627
18%
1711
11%
627
57%
627
33%
1051
September11th to 20thNight
52%
720
17%
1980
11%
720
55%
720
30%
1297
September21st to endNight
46%
720
20%
1980
12%
720
52%
720
34%
1246
October1st to 10thNight
44%
720
18%
2056
11%
720
51%
720
27%
1366
October11th to 20thNight
41%
720
16%
2308
10%
720
49%
720
24%
1498
October21st to endNight
37%
792
16%
2574
11%
792
45%
792
20%
1742
November1st to 10thNight
32%
857
17%
2522
10%
857
40%
857
19%
1792
November11th to 20thNight
32%
950
16%
2764
8%
950
39%
950
23%
1896
November21st to endNight
37%
950
13%
2850
7%
950
42%
950
22%
1940
December1st to 10thNight
38%
950
16%
2850
11%
950
43%
950
20%
2003
December11th to 20thNight
35%
949
14%
3471
9%
949
39%
949
16%
2412
December21st to endNight
35%
1028
12%
4925
9%
1026
42%
1026
15%
2645

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%9%47%6%46%6%6%8%35%
74617
Night
7%9%48%7%46%6%6%8%35%
75109
TransparencyDay
45%8%17%22%9%1
74301
Night
45%7%15%21%10%2
74944
SeeingDay
13%6%25%32%18%6%
14215
Night
12%5%30%36%15%2
23427

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 10thDay
5%11%6%9%6%46%5%5%10%33%
1329
11th to 20thDay
6%11%5%10%7%35%6%7%7%34%
1270
21st to endDay
6%10%6%11%8%37%5%7%8%28%
1584
February1st to 10thDay
6%11%6%9%9%5%6%5%6%8%28%
1440
11th to 20thDay
6%13%5%10%9%5%6%7%7%8%24%
1543
21st to endDay
410%8%11%7%47%6%7%7%28%
1431
March1st to 10thDay
5%11%6%9%10%47%6%6%6%29%
1800
11th to 20thDay
5%10%5%9%6%46%7%7%8%33%
1947
21st to endDay
9%13%6%9%7%46%5%7%6%26%
2218
April1st to 10thDay
8%12%6%8%7%5%6%6%7%8%27%
2214
11th to 20thDay
12%14%6%9%6%35%5%6%8%26%
2310
21st to endDay
12%11%5%7%6%35%5%5%9%31%
2340
May1st to 10thDay
13%12%37%6%46%6%6%8%28%
2514
11th to 20thDay
10%7%36%7%46%5%6%9%38%
2654
21st to endDay
18%7%36%6%36%6%6%8%31%
2917
June1st to 10thDay
17%7%36%7%46%6%6%8%29%
2700
11th to 20thDay
19%9%46%7%5%6%6%7%7%24%
2700
21st to endDay
8%5%36%7%46%7%7%9%37%
2700
July1st to 10thDay
10%6%25%6%45%7%7%10%38%
2700
11th to 20thDay
12%5%25%445%6%8%9%40%
2700
21st to endDay
8%425%435%5%7%11%48%
2902
August1st to 10thDay
10%5%26%5%35%7%7%10%41%
2507
11th to 20thDay
10%424435%5%7%8%47%
2350
21st to endDay
11%5%245%35%6%7%8%45%
2574
September1st to 10thDay
12%6%246%3446%7%46%
2246
11th to 20thDay
15%7%25%5%24447%44%
1980
21st to endDay
9%8%36%5%35%5%6%8%42%
1980
October1st to 10thDay
12%10%46%5%35%5%5%7%39%
1904
11th to 20thDay
10%8%37%6%35%6%7%7%36%
1648
21st to endDay
7%9%5%9%8%47%5%6%8%33%
1782
November1st to 10thDay
9%15%6%9%7%345%6%7%29%
1538
11th to 20thDay
6%12%5%9%7%45%6%5%7%35%
1411
21st to endDay
5%10%5%9%8%46%5%7%8%34%
1330
December1st to 10thDay
6%11%5%12%8%6%6%5%5%7%30%
1330
11th to 20thDay
49%5%12%8%46%7%6%9%30%
1682
21st to endDay
48%49%7%45%5%5%8%41%
2442
January1st to 10thNight
411%6%11%10%46%6%7%8%28%
2836
11th to 20thNight
5%12%6%8%7%47%6%6%10%29%
2730
21st to endNight
5%12%5%9%8%5%6%6%7%8%29%
2787
February1st to 10thNight
6%10%6%11%9%5%6%46%8%29%
2520
11th to 20thNight
5%12%6%10%8%5%7%6%6%7%28%
2304
21st to endNight
310%5%9%7%5%8%5%7%8%33%
1821
March1st to 10thNight
5%9%5%9%8%5%8%7%7%9%28%
2160
11th to 20thNight
5%10%5%10%7%46%6%7%9%31%
2012
21st to endNight
7%12%6%9%8%47%6%7%7%27%
2135
April1st to 10thNight
8%10%5%7%9%5%6%7%6%8%30%
1746
11th to 20thNight
9%13%5%9%8%36%6%5%7%28%
1601
21st to endNight
13%10%38%7%45%6%7%7%31%
1620
May1st to 10thNight
13%10%5%7%6%36%6%6%8%31%
1444
11th to 20thNight
10%6%36%6%45%5%6%9%39%
1239
21st to endNight
18%8%35%6%35%7%6%8%32%
1358
June1st to 10thNight
17%7%47%435%7%7%9%29%
1260
11th to 20thNight
18%9%47%7%5%6%7%5%9%23%
1260
21st to endNight
9%6%36%6%45%6%8%8%39%
1260
July1st to 10thNight
9%6%26%6%46%7%8%8%39%
1260
11th to 20thNight
9%6%25%5%5%7%7%8%9%37%
1260
21st to endNight
7%423445%5%6%10%50%
1413
August1st to 10thNight
8%6%36%6%45%5%7%8%42%
1432
11th to 20thNight
8%5%36%5%35%5%6%10%44%
1550
21st to endNight
9%5%25%5%35%6%6%8%46%
1782
September1st to 10thNight
10%6%25%5%345%6%8%46%
1711
11th to 20thNight
15%6%35%5%35%5%6%7%43%
1980
21st to endNight
11%6%35%445%46%8%45%
1980
October1st to 10thNight
12%8%36%6%445%5%7%41%
2056
11th to 20thNight
8%8%37%7%46%47%8%38%
2308
21st to endNight
7%10%5%8%7%46%6%7%8%34%
2574
November1st to 10thNight
8%13%5%8%6%35%6%6%7%33%
2522
11th to 20thNight
410%5%9%7%46%5%7%8%34%
2764
21st to endNight
410%5%9%7%46%6%7%9%34%
2850
December1st to 10thNight
5%11%5%9%8%46%5%5%7%33%
2850
11th to 20thNight
210%5%11%9%5%7%6%6%7%32%
3510
21st to endNight
39%37%6%45%5%6%8%44%
5214

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 10thDay
47%6%14%23%9%3
1329
11th to 20thDay
47%8%12%22%9%2
1270
21st to endDay
51%7%14%15%11%1
1584
February1st to 10thDay
51%6%12%19%9%3
1440
11th to 20thDay
53%8%15%15%8%1
1552
21st to endDay
53%7%11%18%10%1
1431
March1st to 10thDay
52%7%14%18%8%1
1800
11th to 20thDay
45%7%13%22%11%1
1948
21st to endDay
55%8%15%16%6%1
2218
April1st to 10thDay
50%8%17%16%8%
2214
11th to 20thDay
54%6%11%20%9%
2310
21st to endDay
49%6%16%21%7%1
2340
May1st to 10thDay
52%6%16%19%6%
2514
11th to 20thDay
41%7%17%23%11%
2658
21st to endDay
49%7%16%21%6%1
2918
June1st to 10thDay
50%8%16%20%6%1
2700
11th to 20thDay
55%8%14%17%41
2700
21st to endDay
39%10%21%24%6%1
2700
July1st to 10thDay
37%9%23%23%7%1
2626
11th to 20thDay
37%10%22%25%6%
2619
21st to endDay
29%9%24%29%8%1
2741
August1st to 10thDay
35%9%23%26%6%
2490
11th to 20thDay
31%8%26%26%9%1
2350
21st to endDay
33%9%20%26%10%1
2574
September1st to 10thDay
36%6%21%24%10%3
2246
11th to 20thDay
40%6%14%28%11%1
1980
21st to endDay
38%6%17%24%12%3
1980
October1st to 10thDay
44%6%14%25%9%1
1904
11th to 20thDay
43%8%16%22%9%1
1648
21st to endDay
48%7%11%22%12%1
1782
November1st to 10thDay
54%7%11%18%8%2
1538
11th to 20thDay
47%7%13%22%10%1
1411
21st to endDay
46%8%15%20%9%2
1330
December1st to 10thDay
52%7%12%16%11%2
1330
11th to 20thDay
48%8%16%19%6%1
1684
21st to endDay
38%6%11%21%19%5%
2442
January1st to 10thNight
51%7%12%16%10%4
2836
11th to 20thNight
49%8%13%21%7%3
2730
21st to endNight
50%7%12%18%12%2
2787
February1st to 10thNight
53%6%11%19%10%2
2520
11th to 20thNight
53%7%12%17%10%1
2305
21st to endNight
47%5%12%21%13%2
1821
March1st to 10thNight
48%10%13%21%7%1
2160
11th to 20thNight
45%8%14%19%12%1
2012
21st to endNight
54%6%13%19%7%1
2135
April1st to 10thNight
48%8%14%19%10%1
1746
11th to 20thNight
53%6%12%20%7%1
1601
21st to endNight
49%7%15%20%7%2
1620
May1st to 10thNight
49%6%16%19%9%1
1444
11th to 20thNight
40%9%13%25%14%
1239
21st to endNight
47%7%18%21%6%1
1358
June1st to 10thNight
47%10%15%18%9%
1260
11th to 20thNight
56%8%14%16%5%2
1260
21st to endNight
40%9%20%24%7%1
1260
July1st to 10thNight
39%10%19%25%6%1
1225
11th to 20thNight
39%11%21%21%8%1
1218
21st to endNight
28%9%21%31%10%1
1335
August1st to 10thNight
36%11%21%26%6%
1424
11th to 20thNight
34%8%23%27%8%1
1550
21st to endNight
33%8%18%26%12%2
1782
September1st to 10thNight
34%6%17%25%13%4
1711
11th to 20thNight
38%7%16%23%11%4
1980
21st to endNight
35%6%17%25%13%3
1980
October1st to 10thNight
43%5%14%25%12%1
2056
11th to 20thNight
42%7%16%24%9%2
2308
21st to endNight
46%7%15%22%9%1
2574
November1st to 10thNight
49%7%11%21%10%2
2522
11th to 20thNight
45%6%17%19%12%1
2764
21st to endNight
44%8%16%20%9%3
2850
December1st to 10thNight
49%6%11%21%10%3
2850
11th to 20thNight
49%9%14%21%6%1
3507
21st to endNight
36%6%12%25%15%6%
5214

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 10thDay
5%6%31%31%19%9%
180
11th to 20thDay
8%437%31%15%6%
163
21st to endDay
9%7%26%35%18%6%
176
February1st to 10thDay
11%13%24%34%12%7%
160
11th to 20thDay
13%235%37%11%2
226
21st to endDay
7%328%36%20%6%
297
March1st to 10thDay
9%6%35%30%15%5%
420
11th to 20thDay
9%5%32%34%14%6%
420
21st to endDay
13%7%31%30%15%5%
462
April1st to 10thDay
12%9%33%27%15%4
420
11th to 20thDay
19%10%22%28%17%4
412
21st to endDay
18%6%27%28%16%3
420
May1st to 10thDay
16%10%22%29%17%5%
481
11th to 20thDay
13%7%21%33%21%5%
625
21st to endDay
17%5%16%33%22%7%
679
June1st to 10thDay
18%6%24%34%14%4
630
11th to 20thDay
20%6%23%35%13%3
630
21st to endDay
10%5%23%29%23%10%
630
July1st to 10thDay
13%317%33%25%8%
621
11th to 20thDay
15%419%33%23%6%
618
21st to endDay
7%420%35%25%10%
648
August1st to 10thDay
12%322%31%22%9%
447
11th to 20thDay
10%322%34%24%8%
437
21st to endDay
12%421%33%22%9%
495
September1st to 10thDay
16%5%29%28%17%5%
450
11th to 20thDay
20%6%21%28%19%6%
450
21st to endDay
14%10%26%29%14%6%
450
October1st to 10thDay
16%7%26%28%16%7%
374
11th to 20thDay
13%6%32%29%16%5%
270
21st to endDay
13%10%33%32%9%2
297
November1st to 10thDay
20%424%34%12%4
270
11th to 20thDay
13%10%32%31%12%2
219
21st to endDay
8%6%32%28%20%7%
180
December1st to 10thDay
11%5%30%32%15%7%
180
11th to 20thDay
9%8%39%26%14%3
180
21st to endDay
7%428%32%25%4
198
January1st to 10thNight
9%6%36%34%13%2
950
11th to 20thNight
10%6%37%33%13%1
910
21st to endNight
11%7%34%35%10%2
807
February1st to 10thNight
10%8%29%33%16%3
720
11th to 20thNight
9%6%36%36%13%1
704
21st to endNight
6%5%28%35%21%5%
592
March1st to 10thNight
9%432%36%15%4
720
11th to 20thNight
8%432%39%14%3
720
21st to endNight
13%429%36%15%4
792
April1st to 10thNight
11%6%30%34%17%2
666
11th to 20thNight
16%5%31%36%11%1
533
21st to endNight
17%7%27%37%12%1
540
May1st to 10thNight
17%7%29%32%15%
423
11th to 20thNight
13%329%37%17%1
354
21st to endNight
22%419%37%17%1
389
June1st to 10thNight
19%6%21%38%14%2
360
11th to 20thNight
21%423%36%16%1
360
21st to endNight
12%5%19%39%23%2
360
July1st to 10thNight
13%314%43%26%1
350
11th to 20thNight
14%318%47%18%1
348
21st to endNight
8%318%42%28%2
394
August1st to 10thNight
10%312%38%34%3
358
11th to 20thNight
9%415%45%26%1
482
21st to endNight
11%319%41%26%
594
September1st to 10thNight
14%323%40%18%3
627
11th to 20thNight
18%319%38%20%3
720
21st to endNight
13%330%37%14%2
720
October1st to 10thNight
17%327%36%15%2
720
11th to 20thNight
12%332%37%15%2
720
21st to endNight
10%7%34%36%12%1
792
November1st to 10thNight
16%8%35%29%12%2
857
11th to 20thNight
10%7%41%30%11%2
950
21st to endNight
6%6%39%36%12%2
950
December1st to 10thNight
11%6%31%35%14%2
950
11th to 20thNight
9%6%37%35%12%2
950
21st to endNight
11%433%35%14%2
1045
Page generated at 2024-01-09 14:24:26. Version ac07

Copyright 2024 Attilla Danko


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