Iqaluit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Iqaluit clear sky chart from 2005-11-05 to 2017-12-02.

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%
14726
6%
47505
5%
14697
39%
14697
11%
36998

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
51%
930
13%
3302
12%
925
53%
925
13%
2412
January16th to endNight
45%
992
10%
3228
7%
992
48%
992
12%
2446
February1st to 15thNight
52%
806
9%
2697
9%
806
53%
806
13%
1970
February16th to endNight
49%
631
12%
2164
14%
631
50%
631
13%
1564
March1st to 15thNight
49%
720
12%
2197
8%
720
52%
720
17%
1551
March16th to endNight
43%
767
10%
2036
5%
767
45%
767
17%
1523
April1st to 15thNight
37%
539
7%
1617
5%
539
39%
539
13%
1212
April16th to endNight
31%
363
0%
1290
0%
363
31%
363
7%
1054
May1st to 15thNight
29%
360
0%
1024
0%
360
29%
360
11%
843
May16th to endNight
27%
311
0%
804
0%
311
27%
311
9%
703
June1st to 15thNight
31%
180
0%
540
0%
180
31%
180
10%
437
June16th to endNight
30%
180
0%
540
0%
180
30%
180
8%
444
July1st to 15thNight
38%
192
0%
532
0%
192
38%
192
13%
418
July16th to endNight
40%
376
0%
816
0%
354
42%
354
20%
637
August1st to 15thNight
41%
359
0%
1104
0%
357
41%
357
12%
865
August16th to endNight
36%
424
0%
1471
0%
424
36%
424
11%
1156
September1st to 15thNight
33%
558
3%
1666
3%
558
33%
558
12%
1321
September16th to endNight
21%
717
2%
1983
1%
717
21%
717
6%
1779
October1st to 15thNight
24%
720
5%
2283
4%
720
25%
720
7%
1920
October16th to endNight
25%
809
7%
2736
4%
809
29%
809
9%
2195
November1st to 15thNight
33%
839
4%
3024
4%
839
35%
839
8%
2425
November16th to endNight
30%
1020
7%
3373
5%
1020
31%
1020
8%
2754
December1st to 15thNight
40%
941
7%
3430
5%
941
42%
941
10%
2565
December16th to endNight
42%
992
7%
3648
6%
992
44%
992
8%
2804

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
15%11%5%9%8%45%5%5%7%19%
49040
Night
10%11%5%10%9%5%7%7%6%7%18%
47583
TransparencyDay
62%6%14%13%3
48637
Night
60%7%14%13%4
47505
SeeingDay
22%13%13%21%19%11%
7877
Night
14%16%12%22%23%10%
14730

By Month

Percentage Cloud Cover NE (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
36%211%12%7%10%8%6%5%25%
635
16th to endDay
37%410%9%6%10%10%9%8%18%
996
February1st to 15thDay
7%411%9%5%11%10%8%8%22%
1163
16th to endDay
45%5%9%9%6%8%8%7%8%23%
1309
March1st to 15thDay
26%5%9%8%6%7%11%8%9%23%
1751
16th to endDay
47%5%9%7%5%8%7%7%10%25%
2188
April1st to 15thDay
6%10%48%8%5%7%7%6%7%26%
2340
16th to endDay
9%13%6%10%12%6%7%5%46%18%
2673
May1st to 15thDay
14%13%5%11%10%45%447%16%
2925
16th to endDay
13%15%8%10%7%45%6%6%7%13%
3310
June1st to 15thDay
19%10%7%9%8%45%5%5%6%16%
3420
16th to endDay
23%12%5%8%6%345%5%6%18%
3420
July1st to 15thDay
25%9%46%6%35%5%5%6%21%
3396
16th to endDay
24%8%36%6%2445%6%25%
3294
August1st to 15thDay
20%10%38%6%346%5%7%23%
2850
16th to endDay
25%12%48%6%34446%18%
2718
September1st to 15thDay
24%13%5%9%7%34435%17%
2293
16th to endDay
22%21%7%10%7%3333412%
1977
October1st to 15thDay
20%18%7%9%5%33345%18%
1675
16th to endDay
12%16%8%10%8%35%346%19%
1486
November1st to 15thDay
9%11%5%14%10%5%6%6%6%8%15%
1162
16th to endDay
11%16%6%9%10%5%6%6%6%8%12%
916
December1st to 15thDay
49%5%12%12%5%7%7%7%9%17%
567
16th to endDay
38%6%13%14%8%7%6%6%7%16%
576
January1st to 15thNight
36%28%11%8%12%8%7%8%22%
3302
16th to endNight
28%410%9%7%11%10%9%7%17%
3228
February1st to 15thNight
15%5%10%10%6%10%10%9%9%20%
2695
16th to endNight
47%6%10%10%5%8%8%6%9%22%
2164
March1st to 15thNight
25%48%10%48%12%11%8%23%
2184
16th to endNight
410%6%9%7%6%9%8%7%7%23%
2036
April1st to 15thNight
8%11%5%10%9%5%6%6%45%26%
1617
16th to endNight
8%15%5%13%12%7%7%5%4416%
1290
May1st to 15thNight
15%15%6%10%11%44446%15%
1024
16th to endNight
14%16%11%14%8%44445%11%
802
June1st to 15thNight
18%15%5%9%8%245%47%17%
540
16th to endNight
25%13%5%7%7%3344421%
540
July1st to 15thNight
30%11%34335%46%5%22%
563
16th to endNight
25%7%25%6%35%45%8%25%
874
August1st to 15thNight
24%10%36%5%345%5%6%23%
1110
16th to endNight
26%10%37%5%3435%7%20%
1471
September1st to 15thNight
24%10%38%7%34446%22%
1666
16th to endNight
24%19%8%9%7%25%43310%
1983
October1st to 15thNight
19%20%7%10%5%34445%14%
2283
16th to endNight
12%18%7%12%7%34338%16%
2736
November1st to 15thNight
10%13%6%12%9%5%6%5%6%8%14%
3024
16th to endNight
10%18%7%10%9%5%5%6%5%7%12%
3373
December1st to 15thNight
5%9%6%11%9%5%7%8%8%10%18%
3430
16th to endNight
310%6%11%11%8%9%7%8%8%14%
3648

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
55%9%14%13%6%
636
16th to endDay
53%9%17%13%6%
996
February1st to 15thDay
50%10%16%18%3
1165
16th to endDay
50%8%14%17%7%1
1309
March1st to 15thDay
47%8%16%18%8%
1761
16th to endDay
51%411%21%11%
2188
April1st to 15thDay
54%5%11%17%10%
2340
16th to endDay
68%410%14%1
2673
May1st to 15thDay
67%5%11%12%2
2925
16th to endDay
71%5%10%9%1
3314
June1st to 15thDay
68%6%12%11%1
3420
16th to endDay
65%6%14%12%1
3420
July1st to 15thDay
62%6%16%12%1
3199
16th to endDay
56%8%22%13%
3089
August1st to 15thDay
57%10%19%11%
2832
16th to endDay
66%7%16%8%1
2718
September1st to 15thDay
69%413%10%1
2293
16th to endDay
77%410%7%1
1977
October1st to 15thDay
67%412%12%2
1675
16th to endDay
64%6%10%13%5%
1486
November1st to 15thDay
62%7%14%11%3
1162
16th to endDay
66%7%11%11%2
916
December1st to 15thDay
57%8%12%16%4
567
16th to endDay
63%7%14%10%4
576
January1st to 15thNight
53%8%14%16%6%
3302
16th to endNight
54%9%16%12%6%
3228
February1st to 15thNight
51%10%15%18%4
2697
16th to endNight
53%7%14%17%6%1
2164
March1st to 15thNight
46%9%15%18%9%
2197
16th to endNight
53%5%11%18%9%
2036
April1st to 15thNight
57%46%19%10%
1617
16th to endNight
69%48%12%3
1290
May1st to 15thNight
67%310%14%3
1024
16th to endNight
74%49%9%2
804
June1st to 15thNight
64%6%14%14%
540
16th to endNight
68%5%11%12%1
540
July1st to 15thNight
60%5%13%17%2
532
16th to endNight
55%6%24%12%1
816
August1st to 15thNight
60%7%19%11%1
1104
16th to endNight
61%7%18%10%1
1471
September1st to 15thNight
62%6%18%11%
1666
16th to endNight
78%5%8%6%1
1983
October1st to 15thNight
71%5%11%10%1
2283
16th to endNight
64%6%12%10%4
2736
November1st to 15thNight
63%9%15%9%2
3024
16th to endNight
67%6%11%12%2
3373
December1st to 15thNight
56%8%16%14%3
3430
16th to endNight
59%8%15%13%3
3648

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%414%29%25%17%
47
16th to endDay
10%420%28%21%14%
64
February1st to 15thDay
10%28%35%26%
60
16th to endDay
311%14%24%30%17%
99
March1st to 15thDay
6%12%16%22%25%15%
262
16th to endDay
6%13%16%17%22%23%
288
April1st to 15thDay
10%13%11%20%24%19%
270
16th to endDay
15%17%13%21%21%10%
423
May1st to 15thDay
21%17%16%17%16%10%
585
16th to endDay
17%15%10%23%19%12%
705
June1st to 15thDay
21%16%9%22%18%11%
675
16th to endDay
28%16%12%18%15%8%
675
July1st to 15thDay
31%11%11%19%16%9%
645
16th to endDay
26%15%11%15%19%11%
703
August1st to 15thDay
25%9%10%24%20%9%
607
16th to endDay
29%11%14%20%13%10%
430
September1st to 15thDay
29%10%14%18%16%10%
315
16th to endDay
29%8%16%24%15%6%
313
October1st to 15thDay
27%10%17%23%16%4
270
16th to endDay
18%8%20%27%16%9%
211
November1st to 15thDay
8%116%27%27%17%
90
16th to endDay
25%314%27%22%6%
76
December1st to 15thDay
6%18%18%37%18%
32
16th to endDay
3318%28%34%12%
32
January1st to 15thNight
6%18%7%20%27%20%
930
16th to endNight
6%18%12%21%26%14%
992
February1st to 15thNight
316%9%21%32%15%
809
16th to endNight
5%16%6%22%29%18%
631
March1st to 15thNight
5%18%10%24%27%13%
720
16th to endNight
7%19%12%20%26%13%
767
April1st to 15thNight
10%19%14%27%20%8%
539
16th to endNight
13%18%11%26%23%7%
363
May1st to 15thNight
20%18%11%26%17%5%
360
16th to endNight
16%19%12%23%20%7%
312
June1st to 15thNight
23%18%11%20%23%2
180
16th to endNight
27%19%11%24%16%1
180
July1st to 15thNight
31%13%8%20%23%2
192
16th to endNight
23%17%7%21%24%4
376
August1st to 15thNight
23%11%10%27%22%5%
359
16th to endNight
31%12%9%24%19%3
424
September1st to 15thNight
27%11%15%21%21%3
558
16th to endNight
30%11%17%23%13%3
717
October1st to 15thNight
26%11%20%24%13%3
720
16th to endNight
20%12%18%23%16%8%
809
November1st to 15thNight
14%14%11%23%25%11%
839
16th to endNight
16%17%13%21%18%12%
1020
December1st to 15thNight
7%18%12%21%26%13%
941
16th to endNight
7%18%8%20%28%16%
992
Page generated at 2017-12-03 11:16:42. Version ac04

Copyright 2017 A. Danko


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