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 2017-04-25.

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%
14092
7%
45643
5%
14063
40%
14063
11%
35419

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%
3227
7%
992
48%
992
12%
2445
February1st to 15thNight
52%
805
9%
2696
9%
805
53%
805
13%
1969
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%
766
10%
2035
5%
766
45%
766
17%
1522
April1st to 15thNight
37%
539
7%
1617
5%
539
39%
539
13%
1212
April16th to endNight
31%
353
0%
1255
0%
353
31%
353
7%
1019
May1st to 15thNight
30%
330
0%
940
0%
330
30%
330
12%
766
May16th to endNight
25%
284
0%
736
0%
284
25%
284
8%
650
June1st to 15thNight
32%
165
0%
495
0%
165
32%
165
10%
398
June16th to endNight
29%
165
0%
495
0%
165
29%
165
8%
411
July1st to 15thNight
36%
175
0%
485
0%
175
36%
175
12%
386
July16th to endNight
40%
348
0%
754
0%
326
42%
326
20%
590
August1st to 15thNight
42%
329
0%
1011
0%
327
42%
327
12%
786
August16th to endNight
35%
389
0%
1348
0%
389
35%
389
10%
1074
September1st to 15thNight
34%
511
3%
1526
3%
511
35%
511
13%
1192
September16th to endNight
20%
657
2%
1818
1%
657
20%
657
6%
1637
October1st to 15thNight
25%
660
5%
2093
5%
660
26%
660
8%
1752
October16th to endNight
26%
731
7%
2508
4%
731
30%
731
9%
2000
November1st to 15thNight
33%
760
5%
2784
4%
760
34%
760
8%
2215
November16th to endNight
30%
930
6%
3112
5%
930
32%
930
8%
2531
December1st to 15thNight
41%
930
7%
3397
5%
930
42%
930
10%
2533
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%46%6%5%7%19%
46092
Night
10%11%5%10%9%5%7%7%6%7%18%
45722
TransparencyDay
62%6%14%13%3
45689
Night
59%7%14%13%4
45643
SeeingDay
21%14%13%20%18%11%
6899
Night
13%17%12%22%23%11%
14096

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%
636
16th to endDay
37%410%9%6%10%10%9%8%18%
996
February1st to 15thDay
7%411%9%5%11%10%8%8%21%
1164
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%
2339
16th to endDay
9%13%6%9%12%6%7%5%46%18%
2596
May1st to 15thDay
14%13%5%12%10%45%45%7%17%
2680
16th to endDay
14%15%9%10%7%45%5%6%6%12%
3027
June1st to 15thDay
19%11%6%9%7%445%5%6%17%
3135
16th to endDay
22%12%5%8%6%345%5%6%17%
3135
July1st to 15thDay
26%9%46%6%35%5%5%6%20%
3113
16th to endDay
23%8%36%6%2445%6%25%
3047
August1st to 15thDay
20%9%38%6%346%5%7%23%
2613
16th to endDay
26%12%48%6%345%46%15%
2490
September1st to 15thDay
22%13%5%9%7%34436%19%
2104
16th to endDay
23%20%7%11%7%3333411%
1812
October1st to 15thDay
20%18%7%8%5%33445%18%
1537
16th to endDay
11%15%8%11%9%45%347%18%
1364
November1st to 15thDay
9%12%5%13%9%5%6%6%6%8%15%
1072
16th to endDay
10%16%6%10%10%5%6%6%6%9%12%
847
December1st to 15thDay
49%5%11%11%5%8%7%7%9%18%
561
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%
3227
February1st to 15thNight
15%5%10%10%6%10%10%9%9%20%
2694
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%
2035
April1st to 15thNight
8%11%5%10%9%5%6%6%45%26%
1617
16th to endNight
9%15%5%13%11%7%7%5%4416%
1255
May1st to 15thNight
14%14%6%10%11%45%446%16%
940
16th to endNight
15%16%11%14%8%44445%9%
734
June1st to 15thNight
17%15%5%10%9%245%46%18%
495
16th to endNight
26%13%5%6%6%3344419%
495
July1st to 15thNight
31%11%34325%46%5%21%
517
16th to endNight
24%7%26%5%35%45%8%25%
812
August1st to 15thNight
24%9%36%5%345%5%6%24%
1017
16th to endNight
28%10%37%5%3435%7%18%
1348
September1st to 15thNight
20%11%49%7%34446%23%
1526
16th to endNight
25%18%8%9%7%35%43310%
1818
October1st to 15thNight
20%19%7%10%5%34445%14%
2093
16th to endNight
12%17%7%12%8%34448%17%
2508
November1st to 15thNight
10%14%6%11%9%5%6%6%6%9%14%
2784
16th to endNight
9%17%7%10%9%5%6%7%6%7%11%
3112
December1st to 15thNight
5%9%6%11%9%5%7%8%8%10%18%
3397
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%
637
16th to endDay
53%9%17%13%6%
996
February1st to 15thDay
50%10%16%18%3
1166
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%
2339
16th to endDay
67%410%15%1
2596
May1st to 15thDay
66%5%12%13%2
2680
16th to endDay
73%5%10%8%1
3031
June1st to 15thDay
68%6%12%11%1
3135
16th to endDay
66%5%13%12%1
3135
July1st to 15thDay
63%5%16%12%1
2916
16th to endDay
56%8%22%12%
2842
August1st to 15thDay
57%10%19%12%1
2595
16th to endDay
67%8%16%7%
2490
September1st to 15thDay
67%415%11%1
2104
16th to endDay
78%39%6%1
1812
October1st to 15thDay
66%413%12%2
1537
16th to endDay
63%6%10%14%5%
1364
November1st to 15thDay
61%7%15%11%3
1072
16th to endDay
65%7%11%11%2
847
December1st to 15thDay
57%8%12%16%4
561
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%
3227
February1st to 15thNight
51%10%15%18%4
2696
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%
2035
April1st to 15thNight
57%46%19%10%
1617
16th to endNight
69%49%12%3
1255
May1st to 15thNight
66%411%15%3
940
16th to endNight
74%5%10%8%1
736
June1st to 15thNight
63%6%14%14%
495
16th to endNight
69%5%10%12%1
495
July1st to 15thNight
62%5%12%17%2
485
16th to endNight
55%6%23%13%1
754
August1st to 15thNight
59%7%20%11%1
1011
16th to endNight
63%7%18%10%
1348
September1st to 15thNight
60%6%19%12%1
1526
16th to endNight
79%48%6%1
1818
October1st to 15thNight
71%5%11%10%1
2093
16th to endNight
64%7%12%10%5%
2508
November1st to 15thNight
62%9%15%9%2
2784
16th to endNight
66%7%12%12%2
3112
December1st to 15thNight
56%8%16%15%3
3397
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%11%21%22%11%
398
May1st to 15thDay
20%19%17%18%15%9%
500
16th to endDay
19%18%10%21%17%12%
609
June1st to 15thDay
21%18%10%19%18%11%
585
16th to endDay
28%18%12%17%13%8%
585
July1st to 15thDay
33%12%9%19%14%10%
555
16th to endDay
25%17%10%15%20%10%
619
August1st to 15thDay
23%10%10%26%20%8%
523
16th to endDay
31%13%12%17%13%11%
358
September1st to 15thDay
23%10%14%20%18%12%
255
16th to endDay
32%9%16%21%15%4
253
October1st to 15thDay
26%12%16%23%16%4
225
16th to endDay
11%9%21%29%16%10%
171
November1st to 15thDay
10%21%28%25%15%
60
16th to endDay
19%5%11%35%21%5%
51
December1st to 15thDay
6%20%20%33%20%
30
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%
808
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%
766
April1st to 15thNight
10%19%14%27%20%8%
539
16th to endNight
12%18%11%25%24%7%
353
May1st to 15thNight
19%20%11%27%16%4
330
16th to endNight
16%21%12%23%19%6%
285
June1st to 15thNight
22%20%10%20%24%1
165
16th to endNight
27%21%11%23%15%1
165
July1st to 15thNight
32%14%8%18%22%2
175
16th to endNight
22%19%7%20%24%4
348
August1st to 15thNight
23%12%9%27%22%5%
329
16th to endNight
32%12%8%22%19%3
389
September1st to 15thNight
23%12%15%23%22%2
511
16th to endNight
32%12%17%22%11%3
657
October1st to 15thNight
26%12%19%25%13%3
660
16th to endNight
18%13%18%22%17%9%
731
November1st to 15thNight
15%15%11%22%23%11%
760
16th to endNight
15%18%13%21%18%12%
930
December1st to 15thNight
7%19%12%21%25%13%
930
16th to endNight
7%18%8%20%28%16%
992
Page generated at 2017-04-26 17:21:46. Version ac04

Copyright 2017 A. Danko


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