Fort Chipewyan
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Chipewyan clear sky chart from 2005-11-06 to 2024-02-10.

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
38%
23997
5%
81416
3%
23933
41%
23933
9%
65493

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
27%
1015
4%
5327
2%
1006
29%
1006
3%
4706
January11th to 20thNight
27%
1013
8%
5077
2%
1009
29%
1009
3%
3997
January21st to endNight
29%
1033
4%
5179
4%
1023
31%
1023
5%
4056
February1st to 10thNight
41%
936
8%
2830
6%
936
43%
936
10%
2316
February11th to 20thNight
38%
701
9%
2369
8%
700
42%
700
10%
1900
February21st to endNight
40%
592
9%
1924
5%
592
46%
592
9%
1581
March1st to 10thNight
47%
720
10%
2245
8%
720
50%
720
11%
1805
March11th to 20thNight
35%
720
9%
1980
3%
720
40%
720
11%
1665
March21st to endNight
45%
774
9%
2160
6%
774
47%
774
14%
1724
April1st to 10thNight
42%
540
8%
1628
6%
540
44%
540
10%
1336
April11th to 20thNight
48%
533
11%
1601
10%
533
50%
533
14%
1234
April21st to endNight
43%
478
6%
1384
5%
478
45%
478
12%
1123
May1st to 10thNight
47%
360
0%
1260
0%
360
47%
360
12%
952
May11th to 20thNight
50%
354
0%
1152
0%
354
50%
354
14%
859
May21st to endNight
51%
388
0%
1047
0%
388
51%
388
18%
800
June1st to 10thNight
50%
360
0%
900
0%
360
50%
360
17%
713
June11th to 20thNight
50%
360
0%
900
0%
360
50%
360
12%
747
June21st to endNight
60%
360
0%
900
0%
360
60%
360
19%
701
July1st to 10thNight
58%
350
0%
875
0%
350
58%
350
18%
681
July11th to 20thNight
62%
348
0%
870
0%
348
62%
348
19%
662
July21st to endNight
63%
394
0%
1214
0%
372
65%
372
14%
901
August1st to 10thNight
64%
358
0%
1246
0%
356
64%
356
15%
898
August11th to 20thNight
54%
395
4%
1303
2%
395
56%
395
14%
972
August21st to endNight
48%
594
6%
1782
5%
594
49%
594
12%
1410
September1st to 10thNight
46%
540
5%
1650
4%
540
48%
540
15%
1257
September11th to 20thNight
49%
625
9%
1885
6%
625
52%
625
12%
1482
September21st to endNight
40%
720
9%
1998
4%
720
44%
720
13%
1620
October1st to 10thNight
32%
720
10%
2160
4%
720
38%
720
11%
1715
October11th to 20thNight
34%
720
9%
2305
5%
720
38%
720
11%
1818
October21st to endNight
27%
985
5%
2767
2%
985
30%
985
6%
2417
November1st to 10thNight
29%
925
5%
2670
3%
925
31%
925
6%
2352
November11th to 20thNight
24%
950
5%
2987
2%
950
28%
950
5%
2646
November21st to endNight
24%
950
3%
3040
1%
950
26%
950
5%
2669
December1st to 10thNight
31%
1017
3%
3181
2%
1017
32%
1017
5%
2815
December11th to 20thNight
29%
1039
6%
3943
3%
1039
33%
1039
5%
3326
December21st to endNight
36%
1130
3%
5677
2%
1114
38%
1114
4%
3637

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%9%48%7%46%6%6%8%33%
76903
Night
8%11%5%9%9%5%7%6%6%7%27%
82002
TransparencyDay
34%35%11%15%4
76571
Night
39%33%10%14%4
81915
SeeingDay
13%8%27%31%16%4
15573
Night
13%7%27%33%17%3
24080

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
6%10%6%15%17%8%11%8%4411%
1579
11th to 20thDay
5%9%5%12%9%5%9%12%10%7%17%
1727
21st to endDay
9%19%8%10%9%5%6%5%6%6%17%
2442
February1st to 10thDay
5%10%5%11%11%411%8%6%8%21%
1350
11th to 20thDay
7%11%6%9%9%46%6%8%8%26%
1478
21st to endDay
39%7%11%12%5%8%7%8%7%23%
1332
March1st to 10thDay
5%10%5%10%7%5%7%6%7%7%31%
1713
11th to 20thDay
6%11%7%10%8%46%5%5%6%33%
1979
21st to endDay
5%8%5%8%8%47%7%6%8%34%
2196
April1st to 10thDay
8%12%5%8%6%345%5%7%38%
2330
11th to 20thDay
7%9%47%7%45%5%6%7%39%
2310
21st to endDay
7%9%48%8%46%6%6%8%33%
2573
May1st to 10thDay
8%8%36%6%46%5%6%8%39%
2700
11th to 20thDay
8%6%36%5%35%5%7%8%43%
2741
21st to endDay
10%5%25%5%35%46%9%47%
3226
June1st to 10thDay
11%7%26%6%46%6%7%7%36%
3060
11th to 20thDay
13%7%47%6%46%6%6%8%35%
3060
21st to endDay
8%5%36%6%37%7%7%8%40%
3060
July1st to 10thDay
9%5%35%7%47%6%8%9%37%
3060
11th to 20thDay
11%6%35%5%45%6%8%9%38%
3060
21st to endDay
11%6%36%6%35%5%7%9%40%
3031
August1st to 10thDay
8%5%36%6%45%6%8%9%40%
2686
11th to 20thDay
12%5%36%6%36%5%7%10%36%
2593
21st to endDay
16%7%36%7%35%5%6%8%34%
2574
September1st to 10thDay
14%8%36%6%345%6%8%37%
2310
11th to 20thDay
16%8%37%6%46%5%7%7%32%
2072
21st to endDay
14%7%5%7%7%45%5%7%7%32%
1962
October1st to 10thDay
12%14%6%9%7%35%5%5%5%30%
1800
11th to 20thDay
9%14%7%9%8%3445%8%28%
1639
21st to endDay
11%16%6%11%9%5%6%5%5%8%18%
1584
November1st to 10thDay
14%14%7%12%7%345%5%7%20%
1408
11th to 20thDay
10%16%6%14%11%6%6%45%5%17%
1193
21st to endDay
10%14%8%11%10%5%7%45%5%21%
1140
December1st to 10thDay
6%15%7%15%13%6%10%7%47%11%
998
11th to 20thDay
7%13%8%12%12%6%6%45%7%22%
1199
21st to endDay
6%9%5%9%9%5%7%6%6%6%34%
1738
January1st to 10thNight
6%14%7%13%13%8%10%8%5%412%
5366
11th to 20thNight
5%9%5%11%10%6%11%12%7%6%18%
5168
21st to endNight
7%19%8%12%8%46%6%5%5%21%
5214
February1st to 10thNight
38%6%10%11%6%10%9%6%7%24%
2830
11th to 20thNight
5%11%6%11%9%5%7%7%7%7%26%
2367
21st to endNight
39%5%11%11%5%9%7%6%7%27%
1924
March1st to 10thNight
5%8%5%9%9%5%6%6%5%7%34%
2245
11th to 20thNight
7%11%5%10%8%46%7%5%7%30%
1980
21st to endNight
5%9%5%8%9%5%5%6%5%6%38%
2160
April1st to 10thNight
9%10%48%8%46%6%6%7%31%
1628
11th to 20thNight
7%8%47%6%46%6%7%8%38%
1601
21st to endNight
7%10%5%9%7%45%6%5%8%35%
1384
May1st to 10thNight
9%10%5%6%6%36%6%5%8%36%
1260
11th to 20thNight
8%6%36%6%25%5%6%8%44%
1152
21st to endNight
10%6%345%45%5%6%7%44%
1047
June1st to 10thNight
10%7%38%7%45%5%8%8%35%
900
11th to 20thNight
16%7%26%7%45%7%6%7%33%
900
21st to endNight
8%5%35%6%45%6%9%8%41%
900
July1st to 10thNight
9%5%25%5%5%7%8%9%9%38%
900
11th to 20thNight
10%5%34435%5%9%13%38%
900
21st to endNight
8%326%6%47%6%8%10%40%
1284
August1st to 10thNight
9%6%25%5%45%5%6%8%45%
1253
11th to 20thNight
10%6%25%6%46%6%7%8%40%
1303
21st to endNight
15%5%37%7%46%6%6%8%33%
1782
September1st to 10thNight
12%7%36%7%35%5%6%7%39%
1650
11th to 20thNight
16%7%345%345%5%9%39%
1885
21st to endNight
11%7%48%7%5%6%46%7%35%
1998
October1st to 10thNight
13%11%37%7%45%5%5%8%33%
2160
11th to 20thNight
11%12%6%8%7%35%6%5%7%29%
2305
21st to endNight
12%17%5%11%9%45%5%6%6%20%
2767
November1st to 10thNight
12%16%6%10%8%5%6%5%5%5%22%
2670
11th to 20thNight
10%15%7%14%10%5%5%5%6%5%18%
2987
21st to endNight
10%15%8%13%9%5%6%5%6%6%18%
3040
December1st to 10thNight
7%13%7%12%11%6%8%7%7%7%15%
3181
11th to 20thNight
6%15%7%10%12%7%8%5%5%7%18%
3993
21st to endNight
49%49%8%46%6%6%8%35%
5918

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
64%23%7%5%1
1579
11th to 20thDay
49%24%8%15%4
1744
21st to endDay
54%21%10%11%3
2442
February1st to 10thDay
41%34%9%11%5%
1350
11th to 20thDay
34%38%11%12%5%
1486
21st to endDay
39%35%10%14%2
1332
March1st to 10thDay
34%36%11%15%31
1713
11th to 20thDay
39%35%8%16%2
1980
21st to endDay
29%37%11%21%2
2196
April1st to 10thDay
35%36%8%16%5%1
2330
11th to 20thDay
31%35%8%18%7%1
2310
21st to endDay
34%35%8%18%5%
2573
May1st to 10thDay
28%35%8%19%10%
2700
11th to 20thDay
29%36%11%15%9%1
2745
21st to endDay
24%36%8%17%15%1
3227
June1st to 10thDay
28%36%6%20%9%
3060
11th to 20thDay
32%36%11%15%6%
3060
21st to endDay
27%36%10%19%7%
3060
July1st to 10thDay
26%37%11%20%5%1
2976
11th to 20thDay
29%37%16%16%1
2967
21st to endDay
26%37%14%20%2
2862
August1st to 10thDay
27%37%16%17%3
2668
11th to 20thDay
31%36%16%14%2
2593
21st to endDay
33%36%16%13%1
2574
September1st to 10thDay
29%36%19%14%2
2310
11th to 20thDay
36%36%13%13%1
2072
21st to endDay
35%36%14%13%2
1962
October1st to 10thDay
37%36%10%12%4
1800
11th to 20thDay
35%35%12%17%2
1639
21st to endDay
43%37%10%9%1
1584
November1st to 10thDay
41%40%9%9%
1408
11th to 20thDay
44%39%11%6%
1193
21st to endDay
43%38%8%10%1
1140
December1st to 10thDay
46%40%5%7%2
998
11th to 20thDay
44%31%7%14%3
1200
21st to endDay
37%24%12%24%3
1738
January1st to 10thNight
61%23%7%8%1
5366
11th to 20thNight
50%23%8%14%3
5213
21st to endNight
53%21%11%13%2
5214
February1st to 10thNight
38%35%10%13%5%
2830
11th to 20thNight
35%37%12%13%4
2369
21st to endNight
39%35%10%13%3
1924
March1st to 10thNight
35%36%10%13%5%1
2245
11th to 20thNight
39%35%8%15%2
1980
21st to endNight
33%35%8%20%4
2160
April1st to 10thNight
38%35%8%12%7%
1628
11th to 20thNight
30%35%7%19%8%1
1601
21st to endNight
35%36%418%6%1
1384
May1st to 10thNight
31%35%7%18%8%1
1260
11th to 20thNight
28%36%11%14%11%1
1152
21st to endNight
26%36%417%16%1
1047
June1st to 10thNight
30%36%5%17%12%1
900
11th to 20thNight
35%37%8%15%5%1
900
21st to endNight
26%36%11%18%8%
900
July1st to 10thNight
25%38%15%18%31
875
11th to 20thNight
24%37%20%17%2
870
21st to endNight
25%38%16%18%3
1214
August1st to 10thNight
24%36%15%20%41
1246
11th to 20thNight
28%36%16%16%4
1303
21st to endNight
32%37%14%15%2
1782
September1st to 10thNight
28%36%20%13%3
1650
11th to 20thNight
33%35%12%17%2
1885
21st to endNight
34%36%11%16%3
1998
October1st to 10thNight
33%36%10%16%41
2160
11th to 20thNight
33%37%12%16%3
2305
21st to endNight
44%36%8%9%2
2767
November1st to 10thNight
42%40%8%8%1
2670
11th to 20thNight
43%40%9%7%
2987
21st to endNight
43%39%8%9%1
3040
December1st to 10thNight
43%40%8%8%2
3181
11th to 20thNight
46%32%9%10%3
3991
21st to endNight
34%24%15%20%6%
5918

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
12%429%36%17%2
180
11th to 20thDay
14%6%32%32%14%3
180
21st to endDay
15%14%30%32%7%3
198
February1st to 10thDay
8%8%37%29%11%7%
178
11th to 20thDay
9%7%35%30%12%8%
196
21st to endDay
5%8%27%35%20%5%
198
March1st to 10thDay
7%8%36%27%18%3
318
11th to 20thDay
10%13%37%29%11%1
420
21st to endDay
10%10%35%31%11%3
462
April1st to 10thDay
12%13%35%25%10%4
420
11th to 20thDay
12%11%33%28%13%2
412
21st to endDay
11%10%30%34%13%2
594
May1st to 10thDay
14%8%27%32%17%2
603
11th to 20thDay
10%9%25%32%20%4
625
21st to endDay
12%6%26%36%17%4
794
June1st to 10thDay
16%10%26%30%15%4
810
11th to 20thDay
18%9%26%30%15%3
810
21st to endDay
10%6%23%34%22%5%
810
July1st to 10thDay
13%6%20%37%19%5%
796
11th to 20thDay
12%6%18%37%21%6%
792
21st to endDay
12%5%19%30%25%9%
742
August1st to 10thDay
9%5%20%31%23%12%
626
11th to 20thDay
15%6%26%30%17%5%
595
21st to endDay
17%6%25%29%17%5%
495
September1st to 10thDay
18%9%28%27%15%3
450
11th to 20thDay
17%7%28%27%17%4
450
21st to endDay
16%13%29%26%13%3
432
October1st to 10thDay
20%10%31%24%11%5%
270
11th to 20thDay
23%7%41%21%6%2
270
21st to endDay
16%11%34%23%14%1
297
November1st to 10thDay
16%9%34%30%10%
232
11th to 20thDay
18%14%33%22%9%3
180
21st to endDay
18%8%38%27%8%1
180
December1st to 10thDay
11%6%33%32%14%4
180
11th to 20thDay
14%6%31%28%17%3
180
21st to endDay
10%421%40%21%5%
198
January1st to 10thNight
13%7%30%32%15%3
1040
11th to 20thNight
14%8%32%32%12%2
1040
21st to endNight
15%8%30%33%12%2
1045
February1st to 10thNight
7%7%30%33%18%5%
936
11th to 20thNight
10%6%29%38%16%1
704
21st to endNight
7%6%30%32%22%2
592
March1st to 10thNight
8%7%23%32%27%3
720
11th to 20thNight
11%6%32%35%14%1
720
21st to endNight
8%6%26%37%18%4
774
April1st to 10thNight
12%8%28%31%18%3
540
11th to 20thNight
10%9%22%38%19%2
533
21st to endNight
12%6%28%37%16%2
478
May1st to 10thNight
14%8%23%35%17%3
360
11th to 20thNight
12%7%25%34%20%3
354
21st to endNight
12%325%34%22%3
389
June1st to 10thNight
13%422%38%19%5%
360
11th to 20thNight
19%418%36%21%3
360
21st to endNight
8%318%33%34%4
360
July1st to 10thNight
11%5%19%37%24%5%
350
11th to 20thNight
11%315%40%26%5%
348
21st to endNight
10%314%32%34%7%
394
August1st to 10thNight
11%315%33%30%9%
358
11th to 20thNight
11%5%23%39%20%4
395
21st to endNight
16%422%34%22%3
594
September1st to 10thNight
13%6%25%33%20%4
540
11th to 20thNight
20%5%20%35%18%3
625
21st to endNight
15%8%27%33%15%1
720
October1st to 10thNight
18%9%30%27%13%3
720
11th to 20thNight
18%6%30%30%13%3
720
21st to endNight
19%10%29%28%11%3
985
November1st to 10thNight
19%7%28%30%13%3
925
11th to 20thNight
18%8%31%28%13%2
950
21st to endNight
17%10%33%27%9%2
950
December1st to 10thNight
14%6%30%33%16%2
1017
11th to 20thNight
13%7%30%35%12%3
1040
21st to endNight
13%5%24%35%19%5%
1144
Page generated at 2024-02-07 04:11:55. Version ac07

Copyright 2024 Attilla Danko


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