Crowsnest Pass
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Crowsnest Pass clear sky chart from 2005-11-06 to 2024-02-05.

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
29%
23493
11%
80656
6%
23388
34%
23388
16%
53185

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
16%
946
5%
4702
3%
926
21%
926
6%
3288
January11th to 20thNight
17%
835
15%
4458
5%
816
24%
816
8%
2954
January21st to endNight
16%
836
7%
4851
5%
814
25%
814
8%
3290
February1st to 10thNight
19%
738
9%
2575
4%
738
26%
738
12%
1849
February11th to 20thNight
17%
704
9%
2259
4%
700
24%
700
12%
1610
February21st to endNight
25%
592
12%
1776
8%
592
31%
592
15%
1261
March1st to 10thNight
20%
720
9%
2160
4%
720
28%
720
14%
1550
March11th to 20thNight
27%
720
12%
2016
6%
720
33%
720
17%
1422
March21st to endNight
27%
792
7%
2131
2%
792
31%
792
15%
1563
April1st to 10thNight
27%
707
10%
1787
2%
707
32%
707
17%
1299
April11th to 20thNight
26%
533
12%
1601
6%
533
30%
533
17%
1080
April21st to endNight
26%
540
11%
1620
6%
540
31%
540
17%
1114
May1st to 10thNight
35%
485
8%
1565
7%
485
38%
485
19%
1040
May11th to 20thNight
44%
354
12%
1289
15%
354
47%
354
21%
789
May21st to endNight
39%
388
7%
1358
7%
388
40%
388
16%
936
June1st to 10thNight
38%
360
4%
1260
1%
360
40%
360
17%
827
June11th to 20thNight
29%
360
3%
1260
0%
360
31%
360
15%
861
June21st to endNight
49%
360
7%
1260
1%
360
52%
360
28%
676
July1st to 10thNight
59%
350
9%
1225
4%
350
62%
350
39%
597
July11th to 20thNight
53%
348
14%
1218
13%
348
59%
348
35%
612
July21st to endNight
59%
394
21%
1462
23%
372
71%
372
41%
625
August1st to 10thNight
62%
358
21%
1424
25%
356
70%
356
33%
700
August11th to 20thNight
58%
525
23%
1593
18%
525
63%
525
43%
819
August21st to endNight
47%
594
27%
1782
18%
594
53%
594
35%
969
September1st to 10thNight
48%
679
21%
1765
10%
679
52%
679
37%
1036
September11th to 20thNight
46%
720
20%
1980
12%
720
51%
720
32%
1214
September21st to endNight
35%
720
18%
1980
11%
720
41%
720
27%
1233
October1st to 10thNight
40%
720
16%
2025
11%
720
46%
720
24%
1318
October11th to 20thNight
34%
720
15%
2294
9%
720
42%
720
20%
1407
October21st to endNight
22%
792
11%
2574
5%
792
30%
792
15%
1762
November1st to 10thNight
16%
762
9%
2427
4%
762
23%
762
11%
1750
November11th to 20thNight
15%
950
10%
2690
3%
950
22%
950
13%
1881
November21st to endNight
18%
950
7%
2850
3%
950
22%
950
14%
2022
December1st to 10thNight
20%
950
9%
2850
4%
950
25%
950
13%
2043
December11th to 20thNight
14%
950
5%
3493
2%
949
18%
949
9%
2621
December21st to endNight
16%
1041
5%
5096
3%
1026
20%
1026
8%
3167

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%9%48%7%46%6%7%8%32%
77763
Night
48%48%7%5%7%7%9%9%32%
81048
TransparencyDay
39%14%19%18%9%2
77478
Night
35%16%21%18%8%2
80913
SeeingDay
20%23%29%18%8%2
14162
Night
15%20%30%24%10%1
23503

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
16%6%12%11%7%8%10%11%9%20%
2219
11th to 20thDay
16%5%11%12%6%7%7%9%9%26%
2417
21st to endDay
110%49%9%6%10%10%12%7%21%
2794
February1st to 10thDay
38%5%11%10%6%9%7%9%11%20%
1478
11th to 20thDay
212%8%14%9%5%7%8%8%9%19%
1587
21st to endDay
210%7%15%10%5%7%8%8%8%21%
1480
March1st to 10thDay
210%7%12%10%6%7%7%10%7%23%
1800
11th to 20thDay
311%7%10%9%6%7%8%8%7%25%
1943
21st to endDay
5%16%6%12%9%5%7%6%7%7%19%
2222
April1st to 10thDay
5%14%7%12%10%46%7%8%7%20%
2173
11th to 20thDay
6%16%6%11%9%5%6%6%6%7%22%
2310
21st to endDay
9%14%6%9%6%46%6%6%7%28%
2340
May1st to 10thDay
9%16%5%8%7%45%6%6%8%25%
2394
11th to 20thDay
13%12%37%7%47%6%6%7%28%
2604
21st to endDay
22%12%38%6%45%5%5%6%23%
2917
June1st to 10thDay
15%9%48%9%45%5%7%6%27%
2700
11th to 20thDay
16%9%49%8%46%7%7%7%22%
2700
21st to endDay
8%6%36%7%46%6%6%8%41%
2700
July1st to 10thDay
5%5%25%6%36%5%6%8%49%
2700
11th to 20thDay
5%4245%35%5%7%7%53%
2700
21st to endDay
331443446%8%60%
2765
August1st to 10thDay
6%4245%35%5%6%8%52%
2507
11th to 20thDay
6%425%435%5%6%7%54%
2308
21st to endDay
8%425%435%5%6%8%50%
2574
September1st to 10thDay
10%8%25%435%46%7%47%
2190
11th to 20thDay
10%5%345%35%6%7%9%44%
1980
21st to endDay
8%8%35%5%36%46%8%43%
1980
October1st to 10thDay
10%12%47%7%45%6%6%7%35%
1934
11th to 20thDay
410%48%9%5%5%5%7%8%34%
1662
21st to endDay
411%48%7%6%7%7%7%9%30%
1782
November1st to 10thDay
6%11%5%11%10%5%7%7%7%8%23%
1632
11th to 20thDay
27%6%8%8%5%7%8%10%11%30%
1487
21st to endDay
28%5%9%8%6%7%6%11%11%27%
1330
December1st to 10thDay
18%5%9%7%7%8%8%11%11%25%
1330
11th to 20thDay
28%49%10%7%7%9%13%11%20%
1682
21st to endDay
18%48%7%5%8%9%10%11%30%
2442
January1st to 10thNight
27%6%11%10%6%10%10%12%9%17%
4726
11th to 20thNight
5%5%11%11%6%9%9%8%10%25%
4510
21st to endNight
113%6%9%9%6%9%9%11%7%21%
4862
February1st to 10thNight
39%6%10%10%5%8%9%9%9%22%
2575
11th to 20thNight
210%7%11%8%5%7%7%9%9%24%
2258
21st to endNight
19%412%10%5%9%7%8%8%26%
1776
March1st to 10thNight
27%6%11%10%6%8%7%9%10%24%
2160
11th to 20thNight
37%5%7%8%5%8%8%10%8%30%
2016
21st to endNight
412%5%11%7%5%7%7%8%9%25%
2131
April1st to 10thNight
5%9%5%8%6%47%7%9%9%30%
1787
11th to 20thNight
5%11%49%8%35%6%8%9%31%
1601
21st to endNight
6%13%47%7%45%5%7%9%34%
1620
May1st to 10thNight
9%12%36%6%46%5%5%8%34%
1565
11th to 20thNight
10%8%36%425%8%7%9%37%
1289
21st to endNight
19%10%35%7%35%47%8%29%
1358
June1st to 10thNight
10%8%27%6%47%8%7%7%32%
1260
11th to 20thNight
14%8%27%6%48%7%7%8%30%
1260
21st to endNight
4425%5%26%6%7%8%50%
1260
July1st to 10thNight
5%31343446%8%58%
1260
11th to 20thNight
332442346%8%59%
1260
21st to endNight
331342345%7%66%
1548
August1st to 10thNight
6%42342445%6%59%
1432
11th to 20thNight
6%3133245%6%8%59%
1593
21st to endNight
7%5%233246%5%8%57%
1782
September1st to 10thNight
7%6%144245%5%7%55%
1765
11th to 20thNight
8%7%245%345%6%8%47%
1980
21st to endNight
7%9%36%4335%6%9%44%
1980
October1st to 10thNight
9%9%25%5%3445%8%44%
2025
11th to 20thNight
47%37%6%47%8%8%9%38%
2294
21st to endNight
49%5%9%8%5%7%8%8%10%28%
2574
November1st to 10thNight
5%12%5%9%7%47%6%9%10%25%
2427
11th to 20thNight
27%49%9%6%7%8%10%11%27%
2690
21st to endNight
28%5%9%7%6%8%8%11%11%27%
2850
December1st to 10thNight
27%6%10%9%5%8%8%12%11%24%
2850
11th to 20thNight
19%5%11%9%6%9%9%11%12%17%
3510
21st to endNight
19%48%8%5%8%8%11%10%27%
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
36%23%26%11%21
2219
11th to 20thDay
44%15%17%9%11%4
2441
21st to endDay
30%27%28%12%3
2794
February1st to 10thDay
42%20%20%11%5%1
1478
11th to 20thDay
47%15%20%13%4
1596
21st to endDay
46%13%20%14%5%2
1480
March1st to 10thDay
41%18%22%15%4
1800
11th to 20thDay
40%18%18%17%6%1
1944
21st to endDay
49%16%22%9%41
2222
April1st to 10thDay
49%14%19%16%3
2173
11th to 20thDay
50%12%18%15%4
2310
21st to endDay
48%11%18%17%5%1
2340
May1st to 10thDay
51%10%18%14%6%1
2394
11th to 20thDay
48%11%17%18%6%
2608
21st to endDay
56%10%16%13%5%
2918
June1st to 10thDay
50%11%16%17%5%
2700
11th to 20thDay
51%11%17%14%6%
2700
21st to endDay
34%10%19%23%13%1
2700
July1st to 10thDay
29%10%17%27%14%4
2626
11th to 20thDay
27%8%14%24%22%4
2619
21st to endDay
20%7%13%28%25%6%
2611
August1st to 10thDay
28%8%15%24%19%6%
2490
11th to 20thDay
25%8%17%32%16%3
2308
21st to endDay
28%8%16%27%19%3
2574
September1st to 10thDay
32%7%17%24%15%5%
2190
11th to 20thDay
32%9%17%26%14%2
1980
21st to endDay
32%10%23%23%10%1
1980
October1st to 10thDay
41%12%17%21%8%
1934
11th to 20thDay
35%14%23%18%10%1
1662
21st to endDay
38%16%21%17%7%1
1782
November1st to 10thDay
43%16%21%15%5%1
1632
11th to 20thDay
30%23%27%15%5%
1487
21st to endDay
37%21%21%14%7%1
1330
December1st to 10thDay
34%23%23%12%6%2
1330
11th to 20thDay
35%25%27%9%3
1684
21st to endDay
30%19%23%17%11%1
2442
January1st to 10thNight
38%23%25%10%31
4726
11th to 20thNight
41%16%19%10%8%6%
4548
21st to endNight
32%27%24%12%4
4862
February1st to 10thNight
43%16%19%13%6%2
2575
11th to 20thNight
42%16%23%14%5%
2259
21st to endNight
44%13%18%18%6%2
1776
March1st to 10thNight
39%19%23%15%4
2160
11th to 20thNight
34%19%22%17%6%1
2016
21st to endNight
42%16%24%14%41
2131
April1st to 10thNight
41%13%21%17%8%
1787
11th to 20thNight
42%10%20%23%4
1601
21st to endNight
43%11%18%22%6%1
1620
May1st to 10thNight
42%10%21%19%8%
1565
11th to 20thNight
38%9%22%23%8%
1289
21st to endNight
47%10%19%19%5%
1358
June1st to 10thNight
41%11%23%19%5%1
1260
11th to 20thNight
44%12%19%18%7%
1260
21st to endNight
25%11%22%28%13%2
1260
July1st to 10thNight
20%8%22%32%14%4
1225
11th to 20thNight
23%7%15%26%23%6%
1218
21st to endNight
18%6%14%30%26%6%
1462
August1st to 10thNight
25%6%15%29%19%5%
1424
11th to 20thNight
20%7%18%35%17%2
1593
21st to endNight
24%8%12%32%22%2
1782
September1st to 10thNight
26%7%15%31%15%5%
1765
11th to 20thNight
29%9%17%27%14%3
1980
21st to endNight
30%11%22%23%12%2
1980
October1st to 10thNight
33%13%18%23%11%1
2025
11th to 20thNight
30%14%24%22%8%2
2294
21st to endNight
38%17%21%18%6%
2574
November1st to 10thNight
40%19%20%14%5%1
2427
11th to 20thNight
31%23%26%14%6%
2690
21st to endNight
34%23%22%13%7%1
2850
December1st to 10thNight
34%23%22%13%6%1
2850
11th to 20thNight
38%26%24%9%3
3507
21st to endNight
35%18%23%15%7%3
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
20%24%28%16%6%6%
180
11th to 20thDay
18%21%36%19%42
180
21st to endDay
14%39%32%9%5%2
198
February1st to 10thDay
24%26%34%11%5%
172
11th to 20thDay
17%27%35%16%6%
252
21st to endDay
19%29%35%13%4
346
March1st to 10thDay
20%35%27%12%5%1
420
11th to 20thDay
22%27%27%15%8%1
420
21st to endDay
24%33%25%13%42
462
April1st to 10thDay
23%29%29%15%3
420
11th to 20thDay
22%31%26%15%5%1
412
21st to endDay
25%28%25%13%7%2
420
May1st to 10thDay
21%21%29%18%9%2
423
11th to 20thDay
26%17%24%19%11%4
575
21st to endDay
26%15%22%23%12%2
679
June1st to 10thDay
20%23%26%20%9%2
630
11th to 20thDay
28%23%24%17%8%1
630
21st to endDay
12%17%28%26%14%3
630
July1st to 10thDay
10%16%29%26%17%3
621
11th to 20thDay
11%18%30%27%12%1
618
21st to endDay
7%16%36%26%11%3
511
August1st to 10thDay
11%17%34%26%9%3
447
11th to 20thDay
7%15%38%27%10%3
437
21st to endDay
12%22%34%20%9%2
495
September1st to 10thDay
20%25%27%18%8%2
450
11th to 20thDay
20%18%33%19%9%1
450
21st to endDay
28%25%27%13%5%2
450
October1st to 10thDay
20%25%27%18%8%1
404
11th to 20thDay
24%23%26%16%10%1
270
21st to endDay
28%25%26%15%5%1
297
November1st to 10thDay
30%29%23%14%3
270
11th to 20thDay
26%30%35%7%2
255
21st to endDay
28%23%26%12%6%6%
180
December1st to 10thDay
22%31%26%16%5%1
180
11th to 20thDay
22%31%32%13%11
180
21st to endDay
16%24%33%16%9%2
198
January1st to 10thNight
18%27%34%17%4
950
11th to 20thNight
12%25%41%17%4
836
21st to endNight
11%30%37%17%5%2
836
February1st to 10thNight
14%21%36%21%6%2
738
11th to 20thNight
14%22%37%21%6%
704
21st to endNight
12%20%32%25%10%1
592
March1st to 10thNight
12%23%38%19%8%1
720
11th to 20thNight
17%21%27%27%7%1
720
21st to endNight
16%19%27%28%8%2
792
April1st to 10thNight
14%21%29%24%10%1
707
11th to 20thNight
15%24%26%25%9%1
533
21st to endNight
15%20%31%22%11%1
540
May1st to 10thNight
18%15%26%26%14%1
485
11th to 20thNight
18%9%21%29%21%2
354
21st to endNight
24%10%19%27%19%2
389
June1st to 10thNight
17%16%23%28%14%2
360
11th to 20thNight
21%17%28%22%13%1
360
21st to endNight
6%13%24%36%20%1
360
July1st to 10thNight
8%7%22%37%26%
350
11th to 20thNight
8%10%26%39%16%1
348
21st to endNight
8%8%22%38%24%1
394
August1st to 10thNight
11%5%16%39%27%1
358
11th to 20thNight
9%7%22%34%25%2
525
21st to endNight
10%14%25%34%17%1
594
September1st to 10thNight
14%11%21%29%20%4
679
11th to 20thNight
16%12%23%28%17%5%
720
21st to endNight
18%17%26%23%13%3
720
October1st to 10thNight
20%15%20%32%13%1
720
11th to 20thNight
14%21%26%28%10%1
720
21st to endNight
15%24%32%22%6%1
792
November1st to 10thNight
21%26%31%17%4
762
11th to 20thNight
20%29%33%15%31
950
21st to endNight
16%25%36%17%6%1
950
December1st to 10thNight
12%25%35%20%7%1
950
11th to 20thNight
13%26%40%18%3
950
21st to endNight
13%25%38%18%6%
1045
Page generated at 2024-02-02 03:20:32. Version ac07

Copyright 2024 Attilla Danko


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