Canmore
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Canmore clear sky chart from 2005-11-06 to 2024-02-15.

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
25%
23444
12%
80740
5%
23342
32%
23342
16%
53253

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
9%
947
11%
4695
2%
926
18%
926
7%
3317
January11th to 20thNight
15%
871
20%
4467
5%
854
24%
854
10%
2720
January21st to endNight
12%
834
10%
4848
5%
814
27%
814
8%
3045
February1st to 10thNight
18%
760
9%
2660
5%
760
25%
760
10%
1911
February11th to 20thNight
14%
721
11%
2379
3%
718
24%
718
13%
1680
February21st to endNight
23%
592
15%
1776
6%
592
35%
592
16%
1231
March1st to 10thNight
24%
720
14%
2160
6%
720
34%
720
17%
1494
March11th to 20thNight
21%
720
16%
2049
6%
720
30%
720
20%
1367
March21st to endNight
24%
792
11%
2084
2%
792
30%
792
16%
1546
April1st to 10thNight
24%
716
10%
1796
2%
716
29%
716
15%
1357
April11th to 20thNight
25%
533
11%
1601
5%
533
29%
533
14%
1164
April21st to endNight
25%
540
10%
1620
5%
540
30%
540
15%
1159
May1st to 10thNight
37%
391
7%
1471
7%
391
41%
391
14%
1023
May11th to 20thNight
47%
354
10%
1262
12%
354
49%
354
22%
789
May21st to endNight
37%
388
5%
1358
3%
388
38%
388
15%
957
June1st to 10thNight
33%
360
2%
1260
0%
360
33%
360
14%
890
June11th to 20thNight
28%
360
0%
1260
0%
360
28%
360
13%
900
June21st to endNight
48%
360
1%
1260
0%
360
48%
360
21%
772
July1st to 10thNight
52%
350
2%
1225
0%
350
52%
350
26%
731
July11th to 20thNight
40%
348
7%
1218
3%
348
43%
348
24%
705
July21st to endNight
58%
394
14%
1429
16%
372
65%
372
34%
714
August1st to 10thNight
57%
358
15%
1424
18%
356
65%
356
25%
789
August11th to 20thNight
51%
454
19%
1522
16%
454
57%
454
32%
823
August21st to endNight
44%
594
19%
1782
13%
594
49%
594
31%
1030
September1st to 10thNight
38%
695
17%
1775
7%
695
43%
695
32%
1106
September11th to 20thNight
38%
720
17%
1948
8%
720
43%
720
26%
1272
September21st to endNight
28%
720
19%
1980
8%
720
38%
720
24%
1249
October1st to 10thNight
30%
720
17%
2024
8%
720
39%
720
23%
1346
October11th to 20thNight
25%
720
13%
2340
5%
720
35%
720
17%
1536
October21st to endNight
18%
792
14%
2574
4%
792
31%
792
14%
1790
November1st to 10thNight
12%
778
11%
2443
3%
778
21%
778
13%
1737
November11th to 20thNight
11%
950
13%
2793
2%
950
22%
950
15%
1900
November21st to endNight
15%
950
11%
2850
3%
950
22%
950
14%
1967
December1st to 10thNight
17%
950
14%
2850
4%
950
26%
950
14%
1942
December11th to 20thNight
13%
950
9%
3486
2%
949
20%
949
12%
2343
December21st to endNight
11%
1042
9%
5071
2%
1026
23%
1026
10%
2951

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
7%8%49%8%46%6%7%9%32%
77810
Night
46%48%7%46%7%8%11%36%
81225
TransparencyDay
44%13%16%17%8%1
77521
Night
38%14%19%19%9%2
81094
SeeingDay
18%22%32%19%7%1
14182
Night
11%21%37%22%8%1
23457

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
2213%11%6%7%7%11%12%27%
2219
11th to 20thDay
3410%8%47%8%7%11%38%
2355
21st to endDay
1437%6%5%6%8%11%13%37%
2794
February1st to 10thDay
26%310%10%6%8%7%9%10%30%
1520
11th to 20thDay
16%312%9%7%8%8%8%10%28%
1561
21st to endDay
16%5%13%10%6%9%8%7%10%26%
1480
March1st to 10thDay
16%5%12%10%5%9%7%7%10%29%
1800
11th to 20thDay
17%49%9%5%8%7%8%11%31%
1909
21st to endDay
213%7%13%10%6%7%7%6%9%19%
2268
April1st to 10thDay
412%7%14%10%5%8%7%6%6%19%
2164
11th to 20thDay
5%15%7%15%9%45%5%6%7%21%
2310
21st to endDay
7%16%7%11%7%5%6%5%6%7%24%
2340
May1st to 10thDay
8%16%6%10%7%45%6%7%8%22%
2488
11th to 20thDay
12%11%48%7%36%5%6%7%31%
2629
21st to endDay
21%13%49%7%46%5%5%6%21%
2917
June1st to 10thDay
18%12%48%7%46%6%5%6%23%
2700
11th to 20thDay
22%11%5%9%9%47%5%5%5%19%
2700
21st to endDay
11%7%47%9%47%7%7%8%29%
2700
July1st to 10thDay
10%7%38%8%5%6%6%6%8%34%
2700
11th to 20thDay
10%6%26%7%46%6%7%6%39%
2700
21st to endDay
6%425%7%45%5%7%9%47%
2803
August1st to 10thDay
9%5%37%7%5%6%6%6%8%37%
2507
11th to 20thDay
9%425%6%35%5%7%9%45%
2378
21st to endDay
10%6%26%7%45%5%7%8%41%
2574
September1st to 10thDay
9%9%36%7%445%6%7%41%
2183
11th to 20thDay
10%7%37%6%445%6%8%40%
2011
21st to endDay
7%7%26%6%46%7%7%10%38%
1980
October1st to 10thDay
7%9%46%6%5%7%6%7%8%35%
1932
11th to 20thDay
5%8%5%8%6%46%6%9%9%35%
1620
21st to endDay
28%49%7%46%6%8%10%36%
1782
November1st to 10thDay
210%5%9%7%46%6%8%11%33%
1616
11th to 20thDay
1437%6%5%7%7%10%12%39%
1386
21st to endDay
1438%8%45%7%9%11%39%
1330
December1st to 10thDay
15%38%9%46%7%8%12%38%
1330
11th to 20thDay
15%39%8%5%8%6%10%12%33%
1682
21st to endDay
448%7%37%6%8%11%42%
2442
January1st to 10thNight
5%5%13%10%6%8%8%10%13%23%
4726
11th to 20thNight
1329%9%6%8%9%10%11%33%
4573
21st to endNight
15%48%7%47%8%10%13%34%
4862
February1st to 10thNight
27%310%10%5%9%9%8%10%28%
2660
11th to 20thNight
16%6%11%9%46%7%8%11%30%
2377
21st to endNight
5%49%11%5%9%7%8%10%31%
1776
March1st to 10thNight
15%48%8%5%8%7%10%12%32%
2160
11th to 20thNight
15%48%7%35%7%8%11%40%
2049
21st to endNight
28%5%11%8%46%7%7%11%32%
2084
April1st to 10thNight
39%7%11%8%36%5%7%9%31%
1796
11th to 20thNight
312%5%11%8%35%5%6%8%33%
1601
21st to endNight
413%7%9%6%46%5%6%8%33%
1620
May1st to 10thNight
6%13%5%7%7%46%6%6%8%32%
1471
11th to 20thNight
8%7%46%6%35%6%7%9%41%
1262
21st to endNight
19%9%37%7%35%447%32%
1358
June1st to 10thNight
16%7%46%6%36%5%6%7%34%
1260
11th to 20thNight
18%9%46%6%35%5%6%7%31%
1260
21st to endNight
8%4245%46%7%8%9%43%
1260
July1st to 10thNight
7%6%24435%5%6%10%48%
1260
11th to 20thNight
9%5%24425%5%8%9%46%
1260
21st to endNight
5%3144246%5%8%58%
1513
August1st to 10thNight
6%6%26%5%335%5%8%51%
1432
11th to 20thNight
10%42332445%10%53%
1522
21st to endNight
8%5%244345%7%8%51%
1782
September1st to 10thNight
8%7%244245%6%8%51%
1775
11th to 20thNight
9%7%35%5%345%7%9%44%
1948
21st to endNight
6%8%244335%6%9%49%
1980
October1st to 10thNight
6%9%37%5%345%7%9%42%
2024
11th to 20thNight
49%46%5%45%7%7%10%40%
2340
21st to endNight
28%5%9%7%35%7%9%10%35%
2574
November1st to 10thNight
29%5%8%7%5%7%6%9%12%31%
2443
11th to 20thNight
16%46%6%47%8%9%13%36%
2793
21st to endNight
15%5%9%8%46%6%8%13%34%
2850
December1st to 10thNight
16%38%8%5%7%7%9%13%34%
2850
11th to 20thNight
438%8%5%8%9%10%15%28%
3510
21st to endNight
5%48%7%47%8%8%13%34%
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
37%20%16%17%8%2
2219
11th to 20thDay
38%12%15%15%14%5%
2378
21st to endDay
32%19%24%19%6%1
2794
February1st to 10thDay
43%16%16%15%7%3
1520
11th to 20thDay
45%17%16%15%6%1
1569
21st to endDay
50%14%14%13%8%1
1480
March1st to 10thDay
45%17%19%12%7%1
1800
11th to 20thDay
40%17%19%16%7%1
1910
21st to endDay
58%16%14%9%41
2268
April1st to 10thDay
57%15%15%9%4
2164
11th to 20thDay
59%11%13%13%5%
2310
21st to endDay
58%10%14%13%41
2340
May1st to 10thDay
57%11%14%15%3
2488
11th to 20thDay
49%12%16%17%6%
2633
21st to endDay
61%10%12%13%4
2918
June1st to 10thDay
60%10%11%14%5%
2700
11th to 20thDay
63%11%11%11%4
2700
21st to endDay
47%13%15%17%7%1
2700
July1st to 10thDay
44%11%16%18%11%2
2626
11th to 20thDay
42%9%14%20%12%2
2619
21st to endDay
32%10%13%26%17%1
2647
August1st to 10thDay
42%11%13%21%11%2
2490
11th to 20thDay
34%11%16%27%11%1
2378
21st to endDay
38%11%14%25%11%1
2574
September1st to 10thDay
40%9%15%22%11%2
2183
11th to 20thDay
39%11%15%21%12%1
2011
21st to endDay
36%15%19%20%8%1
1980
October1st to 10thDay
42%15%13%20%9%1
1932
11th to 20thDay
40%13%19%19%8%1
1620
21st to endDay
40%14%20%17%9%
1782
November1st to 10thDay
42%16%21%15%6%1
1616
11th to 20thDay
31%20%25%17%7%1
1386
21st to endDay
34%18%24%17%6%2
1330
December1st to 10thDay
36%16%21%16%10%1
1330
11th to 20thDay
35%17%25%16%6%1
1684
21st to endDay
31%13%16%21%14%5%
2442
January1st to 10thNight
45%17%17%15%5%1
4726
11th to 20thNight
38%12%16%14%12%8%
4612
21st to endNight
36%18%23%15%7%1
4862
February1st to 10thNight
43%17%16%14%8%2
2660
11th to 20thNight
43%15%19%15%7%1
2379
21st to endNight
43%12%15%18%10%1
1776
March1st to 10thNight
38%16%21%17%8%1
2160
11th to 20thNight
34%15%22%18%10%1
2049
21st to endNight
44%14%17%17%7%1
2084
April1st to 10thNight
47%13%18%16%6%
1796
11th to 20thNight
49%10%18%16%7%1
1601
21st to endNight
48%10%17%18%6%1
1620
May1st to 10thNight
48%11%17%18%6%
1471
11th to 20thNight
39%9%21%25%6%
1262
21st to endNight
52%8%15%21%6%
1358
June1st to 10thNight
48%10%15%20%6%
1260
11th to 20thNight
51%9%16%15%8%
1260
21st to endNight
33%13%19%27%7%1
1260
July1st to 10thNight
32%10%19%25%12%2
1225
11th to 20thNight
32%9%17%27%13%1
1218
21st to endNight
23%9%17%31%19%1
1429
August1st to 10thNight
32%8%18%29%11%2
1424
11th to 20thNight
26%9%21%34%9%
1522
21st to endNight
28%9%19%31%12%1
1782
September1st to 10thNight
30%9%20%29%11%1
1775
11th to 20thNight
35%10%18%24%11%2
1948
21st to endNight
31%10%22%25%11%
1980
October1st to 10thNight
36%12%17%23%12%
2024
11th to 20thNight
35%15%20%21%9%1
2340
21st to endNight
39%16%17%21%7%
2574
November1st to 10thNight
40%18%19%15%7%2
2443
11th to 20thNight
32%19%23%17%8%1
2793
21st to endNight
36%17%21%16%7%3
2850
December1st to 10thNight
35%18%19%17%9%2
2850
11th to 20thNight
37%17%25%14%6%
3507
21st to endNight
33%15%20%17%10%5%
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
16%21%38%17%43
180
11th to 20thDay
9%31%38%16%6%1
180
21st to endDay
10%34%36%13%5%2
198
February1st to 10thDay
25%23%32%13%42
180
11th to 20thDay
14%21%45%16%31
235
21st to endDay
15%25%36%19%41
346
March1st to 10thDay
14%32%31%17%5%2
420
11th to 20thDay
17%27%36%15%42
420
21st to endDay
17%27%33%16%5%2
462
April1st to 10thDay
18%26%35%17%4
420
11th to 20thDay
19%24%31%18%7%1
412
21st to endDay
20%24%34%15%6%2
420
May1st to 10thDay
19%18%30%22%9%2
423
11th to 20thDay
20%11%27%27%13%2
600
21st to endDay
25%12%24%26%11%2
679
June1st to 10thDay
23%18%29%21%8%1
630
11th to 20thDay
27%20%27%19%7%
630
21st to endDay
16%16%33%22%11%2
630
July1st to 10thDay
16%14%30%24%14%2
621
11th to 20thDay
16%21%32%22%9%1
618
21st to endDay
9%19%32%28%9%2
549
August1st to 10thDay
15%16%35%25%8%1
447
11th to 20thDay
12%20%36%25%6%1
437
21st to endDay
16%19%36%21%6%1
495
September1st to 10thDay
22%24%33%14%6%1
450
11th to 20thDay
19%22%37%17%5%1
450
21st to endDay
26%29%27%15%31
450
October1st to 10thDay
23%22%31%17%7%1
419
11th to 20thDay
19%26%30%21%31
270
21st to endDay
20%29%36%11%41
297
November1st to 10thDay
17%32%34%10%5%1
270
11th to 20thDay
14%30%45%8%2
206
21st to endDay
16%28%29%16%8%4
180
December1st to 10thDay
13%31%31%17%6%2
180
11th to 20thDay
9%35%38%14%31
180
21st to endDay
11%28%38%19%41
198
January1st to 10thNight
10%30%46%11%2
950
11th to 20thNight
8%29%45%15%31
874
21st to endNight
8%32%41%15%4
836
February1st to 10thNight
12%24%38%19%7%1
760
11th to 20thNight
8%23%45%19%5%
722
21st to endNight
8%17%43%24%8%1
592
March1st to 10thNight
5%23%44%21%7%1
720
11th to 20thNight
8%24%43%19%6%1
720
21st to endNight
8%19%39%23%10%1
792
April1st to 10thNight
11%18%35%29%7%1
716
11th to 20thNight
10%19%34%30%7%1
533
21st to endNight
13%17%37%25%7%1
540
May1st to 10thNight
13%10%32%34%10%1
391
11th to 20thNight
13%6%27%34%19%1
354
21st to endNight
23%8%25%25%17%2
389
June1st to 10thNight
19%13%31%23%13%1
360
11th to 20thNight
21%12%32%26%10%
360
21st to endNight
11%13%24%34%18%1
360
July1st to 10thNight
11%7%27%39%16%1
350
11th to 20thNight
13%12%30%32%12%1
348
21st to endNight
8%7%20%48%17%
394
August1st to 10thNight
10%7%20%43%19%1
358
11th to 20thNight
12%10%24%34%19%2
454
21st to endNight
12%11%29%31%15%1
594
September1st to 10thNight
14%13%31%28%12%2
695
11th to 20thNight
13%14%32%25%13%3
720
21st to endNight
15%22%32%21%9%1
720
October1st to 10thNight
14%15%36%25%9%
720
11th to 20thNight
12%21%38%24%5%1
720
21st to endNight
12%26%39%19%4
792
November1st to 10thNight
12%29%42%13%3
778
11th to 20thNight
11%33%43%11%21
950
21st to endNight
10%30%40%16%31
950
December1st to 10thNight
8%31%39%17%5%
950
11th to 20thNight
8%30%44%14%4
950
21st to endNight
7%27%46%14%5%
1045
Page generated at 2024-02-12 04:35:34. Version ac07

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