Cold Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cold Lake clear sky chart from 2005-11-05 to 2017-12-20.

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
34%
15750
9%
48015
6%
15722
38%
15722
15%
35003

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
29%
895
7%
2685
3%
895
32%
895
12%
2096
January16th to endNight
26%
960
12%
2880
5%
960
33%
960
13%
2143
February1st to 15thNight
33%
745
9%
2415
7%
741
37%
741
12%
1801
February16th to endNight
36%
632
12%
2052
10%
632
41%
632
13%
1543
March1st to 15thNight
30%
720
11%
2109
7%
720
35%
720
16%
1597
March16th to endNight
36%
756
11%
2101
8%
756
39%
756
15%
1595
April1st to 15thNight
33%
539
14%
1677
8%
539
38%
539
16%
1163
April16th to endNight
31%
540
14%
1551
8%
540
38%
540
17%
1084
May1st to 15thNight
38%
442
7%
1342
5%
442
39%
442
20%
891
May16th to endNight
39%
374
0%
1287
0%
374
39%
374
15%
902
June1st to 15thNight
34%
360
0%
1080
0%
360
34%
360
13%
789
June16th to endNight
44%
360
0%
1080
0%
360
44%
360
16%
772
July1st to 15thNight
48%
340
0%
1125
0%
340
48%
340
21%
700
July16th to endNight
50%
376
1%
1239
0%
354
54%
354
24%
743
August1st to 15thNight
58%
426
7%
1337
6%
424
60%
424
27%
813
August16th to endNight
52%
573
13%
1719
10%
573
56%
573
26%
1086
September1st to 15thNight
46%
540
12%
1746
9%
540
51%
540
24%
1092
September16th to endNight
47%
707
17%
1990
11%
707
53%
707
31%
1245
October1st to 15thNight
33%
720
13%
2160
8%
720
38%
720
17%
1555
October16th to endNight
31%
861
11%
2556
6%
861
36%
861
16%
1876
November1st to 15thNight
29%
950
12%
2660
7%
950
33%
950
13%
2107
November16th to endNight
23%
975
7%
2963
2%
975
29%
975
10%
2347
December1st to 15thNight
25%
975
5%
3120
3%
975
27%
975
8%
2562
December16th to endNight
24%
984
9%
3141
4%
984
31%
984
9%
2501

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
12%8%37%6%35%5%6%7%32%
48861
Night
10%9%48%7%45%5%5%7%31%
48172
TransparencyDay
49%8%17%18%5%
48510
Night
51%7%15%18%5%
48027
SeeingDay
14%13%23%26%16%4
6443
Night
13%17%22%29%14%2
15762

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
10%15%6%9%7%5%45%5%7%23%
1253
16th to endDay
8%12%6%10%8%44345%28%
1344
February1st to 15thDay
8%9%5%8%9%5%7%6%6%5%26%
1449
16th to endDay
8%11%6%13%10%5%5%5%6%7%19%
1422
March1st to 15thDay
9%10%410%7%45%5%6%9%25%
1851
16th to endDay
9%13%5%9%6%35%5%5%6%27%
2122
April1st to 15thDay
13%11%46%6%4435%7%31%
2269
16th to endDay
14%11%47%6%35%5%46%30%
2409
May1st to 15thDay
10%436%6%35%5%6%8%39%
2607
16th to endDay
16%6%25%435%5%5%7%37%
2823
June1st to 15thDay
17%7%37%7%35%5%6%8%28%
2880
16th to endDay
19%7%37%5%35%5%6%7%27%
2880
July1st to 15thDay
12%6%25%435%5%6%8%39%
2765
16th to endDay
10%425%5%36%6%7%10%38%
2846
August1st to 15thDay
12%5%25%5%35%5%6%7%39%
2616
16th to endDay
9%5%25%5%345%7%9%39%
2483
September1st to 15thDay
13%7%245%23447%43%
2214
16th to endDay
13%425%5%3445%9%40%
1968
October1st to 15thDay
15%11%35%6%3446%6%32%
1800
16th to endDay
11%11%5%5%5%35%5%5%7%31%
1654
November1st to 15thDay
12%9%410%7%46%5%5%7%26%
1528
16th to endDay
7%12%5%12%7%46%5%6%7%24%
1326
December1st to 15thDay
8%12%6%12%11%47%447%19%
1170
16th to endDay
6%12%412%10%36%7%8%7%19%
1182
January1st to 15thNight
9%10%5%10%9%5%6%5%5%7%22%
2685
16th to endNight
7%11%5%9%7%46%45%7%29%
2880
February1st to 15thNight
8%10%5%9%8%46%447%28%
2415
16th to endNight
6%10%7%10%8%5%5%6%5%6%26%
2052
March1st to 15thNight
9%11%5%9%6%46%6%5%7%27%
2109
16th to endNight
11%13%5%8%6%35%45%7%27%
2098
April1st to 15thNight
11%8%37%6%35%46%8%34%
1677
16th to endNight
13%10%46%6%23445%37%
1551
May1st to 15thNight
12%8%36%6%2345%6%39%
1342
16th to endNight
16%6%46%6%25%46%8%31%
1287
June1st to 15thNight
17%8%46%6%3446%7%29%
1080
16th to endNight
16%5%26%5%37%5%6%9%32%
1080
July1st to 15thNight
10%425%5%25%5%6%9%42%
1194
16th to endNight
9%325%5%35%6%6%9%43%
1323
August1st to 15thNight
8%225%4346%7%10%44%
1344
16th to endNight
9%425%5%345%6%8%45%
1719
September1st to 15thNight
13%7%145%2445%5%46%
1746
16th to endNight
11%3243245%6%10%45%
1990
October1st to 15thNight
16%9%37%5%24445%34%
2160
16th to endNight
12%12%46%5%35%5%6%6%31%
2556
November1st to 15thNight
13%12%6%7%7%35%5%5%5%27%
2660
16th to endNight
7%11%6%12%8%35%45%7%25%
2963
December1st to 15thNight
10%13%5%10%8%6%5%5%6%6%20%
3120
16th to endNight
5%12%7%13%11%46%6%6%6%20%
3141

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
60%7%15%13%3
1253
16th to endDay
58%6%13%15%5%1
1344
February1st to 15thDay
55%9%16%12%6%
1449
16th to endDay
61%5%13%13%5%
1422
March1st to 15thDay
55%8%16%16%3
1851
16th to endDay
55%7%15%16%4
2123
April1st to 15thDay
51%7%17%16%6%1
2269
16th to endDay
54%6%12%17%7%1
2409
May1st to 15thDay
39%8%14%25%11%
2607
16th to endDay
45%7%14%20%11%
2828
June1st to 15thDay
51%9%15%16%6%
2880
16th to endDay
55%8%13%18%3
2880
July1st to 15thDay
40%10%19%24%4
2605
16th to endDay
39%11%28%19%1
2667
August1st to 15thDay
40%10%25%21%2
2598
16th to endDay
38%9%27%21%2
2483
September1st to 15thDay
39%8%20%23%6%1
2214
16th to endDay
39%7%22%23%6%
1968
October1st to 15thDay
52%8%16%19%3
1800
16th to endDay
51%8%18%17%3
1654
November1st to 15thDay
57%8%14%14%3
1528
16th to endDay
61%8%14%13%2
1326
December1st to 15thDay
68%7%8%14%1
1170
16th to endDay
60%10%14%9%5%
1182
January1st to 15thNight
59%7%16%13%3
2685
16th to endNight
53%8%13%17%5%1
2880
February1st to 15thNight
54%8%13%18%5%
2426
16th to endNight
55%7%12%17%6%
2052
March1st to 15thNight
54%7%15%18%4
2109
16th to endNight
54%6%12%18%6%
2101
April1st to 15thNight
47%8%13%20%9%1
1677
16th to endNight
47%5%11%18%14%2
1551
May1st to 15thNight
44%5%8%25%13%2
1343
16th to endNight
49%8%9%18%11%2
1287
June1st to 15thNight
51%8%12%17%9%1
1080
16th to endNight
49%8%15%17%8%1
1080
July1st to 15thNight
36%9%19%27%6%
1125
16th to endNight
34%9%28%25%1
1239
August1st to 15thNight
33%8%26%27%2
1337
16th to endNight
35%9%22%26%5%
1719
September1st to 15thNight
40%5%19%24%8%2
1746
16th to endNight
34%7%20%27%8%1
1990
October1st to 15thNight
52%5%13%22%5%
2160
16th to endNight
52%7%17%18%3
2556
November1st to 15thNight
59%8%10%16%5%
2660
16th to endNight
60%9%16%12%2
2963
December1st to 15thNight
65%8%13%10%1
3120
16th to endNight
61%8%12%12%3
3141

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
8%320%38%21%8%
60
16th to endDay
17%428%34%14%1
64
February1st to 15thDay
12%8%40%29%10%
75
16th to endDay
13%6%17%44%16%2
81
March1st to 15thDay
16%18%32%25%6%
213
16th to endDay
13%18%31%25%9%2
288
April1st to 15thDay
19%19%34%17%8%1
269
16th to endDay
19%17%22%25%12%2
339
May1st to 15thDay
8%18%21%27%17%5%
468
16th to endDay
12%16%19%24%18%8%
517
June1st to 15thDay
17%17%22%22%15%4
495
16th to endDay
19%15%17%21%19%6%
495
July1st to 15thDay
10%10%20%33%20%3
475
16th to endDay
10%15%20%25%21%6%
515
August1st to 15thDay
14%9%14%24%26%9%
475
16th to endDay
9%12%23%32%20%1
332
September1st to 15thDay
17%11%26%24%17%3
315
16th to endDay
14%12%22%29%16%3
296
October1st to 15thDay
26%10%25%22%12%2
135
16th to endDay
27%9%27%20%13%1
144
November1st to 15thDay
17%232%33%12%
135
16th to endDay
16%7%37%22%7%8%
95
December1st to 15thDay
10%233%41%48%
90
16th to endDay
8%436%29%18%4
72
January1st to 15thNight
11%20%21%30%13%2
900
16th to endNight
11%21%29%28%7%2
960
February1st to 15thNight
11%19%18%33%15%2
749
16th to endNight
9%16%20%35%15%2
632
March1st to 15thNight
10%19%26%32%9%1
720
16th to endNight
12%19%18%29%16%3
757
April1st to 15thNight
13%20%23%28%12%1
539
16th to endNight
17%21%17%26%15%1
540
May1st to 15thNight
10%20%22%28%16%
443
16th to endNight
15%19%16%25%19%3
375
June1st to 15thNight
19%19%14%26%18%2
360
16th to endNight
14%19%13%26%22%3
360
July1st to 15thNight
12%12%16%31%24%2
340
16th to endNight
10%18%13%28%24%5%
376
August1st to 15thNight
9%10%13%29%29%7%
426
16th to endNight
10%10%16%39%21%1
573
September1st to 15thNight
16%12%18%30%21%
540
16th to endNight
10%11%24%35%16%1
707
October1st to 15thNight
19%10%26%27%12%2
720
16th to endNight
19%13%28%27%9%
861
November1st to 15thNight
17%16%25%28%10%2
950
16th to endNight
11%20%29%27%9%2
975
December1st to 15thNight
13%17%25%27%12%3
975
16th to endNight
7%19%23%27%17%4
984
Page generated at 2017-12-21 05:04:50. Version ac04

Copyright 2017 A. Danko


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