Igloolik
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Igloolik clear sky chart from 2005-11-05 to 2017-09-21.

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
52%
13517
5%
47481
5%
13510
52%
13510
12%
36071

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
60%
985
4%
4297
6%
985
60%
985
10%
3138
January16th to endNight
65%
1011
10%
3859
11%
1011
67%
1011
16%
2606
February1st to 15thNight
65%
896
6%
2975
7%
893
65%
893
14%
2234
February16th to endNight
64%
789
11%
2312
9%
789
65%
789
21%
1635
March1st to 15thNight
63%
720
9%
2255
9%
720
64%
720
20%
1563
March16th to endNight
65%
706
8%
1999
7%
706
66%
706
25%
1353
April1st to 15thNight
61%
468
0%
1487
0%
468
61%
468
21%
1021
April16th to endNight
51%
360
0%
1089
0%
360
51%
360
15%
840
May1st to 15thNight
43%
238
0%
642
0%
238
43%
238
16%
503
May16th to endNight0
0%
6400
0%
41
June1st to 15thNight00000
June16th to endNight00000
July1st to 15thNight00000
July16th to endNight
46%
45
0%
171
0%
42
47%
42
7%
120
August1st to 15thNight
51%
273
0%
738
0%
272
51%
272
20%
545
August16th to endNight
44%
382
0%
1245
0%
382
44%
382
14%
942
September1st to 15thNight
47%
525
0%
1593
0%
525
47%
525
17%
1161
September16th to endNight
31%
681
3%
1887
2%
681
32%
681
9%
1622
October1st to 15thNight
26%
660
4%
2163
3%
660
26%
660
7%
1846
October16th to endNight
28%
862
4%
2694
3%
862
29%
862
6%
2372
November1st to 15thNight
49%
905
4%
3146
3%
905
50%
905
10%
2519
November16th to endNight
44%
965
3%
3937
4%
965
44%
965
6%
3253
December1st to 15thNight
53%
990
6%
4320
6%
990
55%
990
9%
3276
December16th to endNight
54%
1056
4%
4608
6%
1056
54%
1056
9%
3481

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%10%48%7%45%5%6%7%26%
50302
Night
5%8%5%11%11%6%8%7%7%8%18%
47486
TransparencyDay
54%7%16%17%3
49785
Night
58%7%15%14%3
47481
SeeingDay
17%19%21%29%20%
9139
Night
9%19%24%33%21%
13527

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
January16th to endDay
4110%12%6%49%11%12%25%
388
February1st to 15thDay
1439%9%8%9%10%10%14%18%
888
16th to endDay
5%37%10%8%11%8%9%12%21%
1160
March1st to 15thDay
15%37%9%6%9%9%9%10%26%
1704
16th to endDay
26%46%7%5%8%9%11%13%24%
2232
April1st to 15thDay
48%47%8%7%8%6%6%9%28%
2462
16th to endDay
49%5%11%11%6%8%5%46%25%
2871
May1st to 15thDay
9%11%6%11%10%35%5%5%7%25%
3307
16th to endDay
9%12%7%11%7%45%5%5%7%22%
4286
June1st to 15thDay
16%14%6%9%6%35%45%6%21%
4320
16th to endDay
17%10%46%5%3445%6%29%
4320
July1st to 15thDay
9%6%35%6%35%5%6%9%37%
4320
16th to endDay
21%8%36%6%345%5%6%27%
4140
August1st to 15thDay
16%8%25%5%2445%7%36%
3219
16th to endDay
20%9%37%5%34346%31%
2956
September1st to 15thDay
14%9%46%5%35%45%8%33%
2355
16th to endDay
19%16%8%10%6%23345%19%
1864
October1st to 15thDay
15%16%7%17%6%3333319%
1466
16th to endDay
9%19%5%14%15%6%433313%
1177
November1st to 15thDay
411%48%14%8%12%8%5%6%15%
712
16th to endDay
15%12%9%10%9%19%7%7%113%
155
January1st to 15thNight
25%410%12%7%11%9%9%11%15%
4297
16th to endNight
4310%10%7%8%9%11%13%19%
3859
February1st to 15thNight
24210%10%8%13%10%10%10%15%
2964
16th to endNight
1339%14%5%9%9%9%13%20%
2312
March1st to 15thNight
15%5%8%9%5%9%9%8%10%24%
2255
16th to endNight
2437%8%5%8%11%11%14%22%
1998
April1st to 15thNight
48%5%7%8%47%7%6%9%29%
1487
16th to endNight
6%8%39%13%7%9%5%5%7%22%
1089
May1st to 15thNight
10%11%6%15%8%34447%23%
642
16th to endNight
415%6%25%117%147%23%
64
July16th to endNight
20%10%28%46%9%137%24%
185
August1st to 15thNight
16%9%47%433345%36%
741
16th to endNight
22%11%36%6%43346%26%
1245
September1st to 15thNight
14%14%46%5%3345%7%30%
1593
16th to endNight
19%17%10%10%6%2433417%
1887
October1st to 15thNight
14%17%9%20%6%1333316%
2163
16th to endNight
10%15%7%18%15%6%433411%
2694
November1st to 15thNight
48%5%11%15%11%9%6%5%6%16%
3146
16th to endNight
8%13%8%10%10%8%11%7%5%5%9%
3937
December1st to 15thNight
17%6%12%13%7%9%9%7%9%16%
4320
16th to endNight
36%5%13%13%8%9%7%9%9%13%
4608

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
January16th to endDay
43%6%16%20%13%
388
February1st to 15thDay
47%9%24%15%2
888
16th to endDay
48%7%16%15%11%
1160
March1st to 15thDay
46%7%19%17%8%
1704
16th to endDay
43%7%14%23%11%
2235
April1st to 15thDay
50%6%13%20%8%
2462
16th to endDay
58%5%8%21%6%
2871
May1st to 15thDay
58%6%10%20%4
3308
16th to endDay
60%8%13%15%
4291
June1st to 15thDay
61%7%13%15%1
4320
16th to endDay
52%7%18%20%1
4320
July1st to 15thDay
41%10%22%22%2
4071
16th to endDay
53%8%19%16%1
3885
August1st to 15thDay
46%8%22%18%3
3197
16th to endDay
53%7%19%17%2
2956
September1st to 15thDay
48%10%24%15%1
2355
16th to endDay
67%7%13%9%
1864
October1st to 15thDay
70%5%10%10%2
1466
16th to endDay
75%6%11%5%1
1177
November1st to 15thDay
61%10%14%11%1
712
16th to endDay
69%313%12%1
155
January1st to 15thNight
55%9%19%15%
4297
16th to endNight
48%7%17%18%8%
3859
February1st to 15thNight
54%9%19%14%1
2975
16th to endNight
48%7%16%16%9%1
2312
March1st to 15thNight
48%6%18%17%8%
2255
16th to endNight
42%8%16%20%12%
1999
April1st to 15thNight
47%5%14%23%8%
1487
16th to endNight
59%5%8%21%4
1089
May1st to 15thNight
59%6%9%21%4
642
16th to endNight
60%314%18%3
64
July16th to endNight
56%8%13%19%2
171
August1st to 15thNight
50%7%17%21%2
738
16th to endNight
58%6%18%14%2
1245
September1st to 15thNight
52%7%25%13%1
1593
16th to endNight
71%6%11%10%1
1887
October1st to 15thNight
74%410%8%1
2163
16th to endNight
77%5%10%6%1
2694
November1st to 15thNight
63%8%15%11%1
3146
16th to endNight
70%6%13%9%
3937
December1st to 15thNight
59%9%15%13%2
4320
16th to endNight
60%7%17%12%2
4608

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
January16th to endDay
5%10%5%55%25%
20
February1st to 15thDay
1131%64%
54
16th to endDay
3432%29%29%
64
March1st to 15thDay
4117%17%31%27%
111
16th to endDay
49%17%36%32%
288
April1st to 15thDay
10%17%22%34%22%
329
16th to endDay
8%19%21%29%30%
549
May1st to 15thDay
14%112%22%25%23%
648
16th to endDay
14%6%21%33%23%
1014
June1st to 15thDay
21%29%18%25%22%
1035
16th to endDay
22%19%25%24%15%
1035
July1st to 15thDay
12%17%24%33%19%
985
16th to endDay
23%38%20%26%17%
935
August1st to 15thDay
21%27%20%30%17%
673
16th to endDay
22%210%24%25%14%
564
September1st to 15thDay
17%312%19%33%13%
327
16th to endDay
24%10%24%25%14%
275
October1st to 15thDay
21%49%25%21%18%
116
16th to endDay
9%16%25%43%14%
64
November1st to 15thDay
9%9%33%33%13%
53
January1st to 15thNight
4421%39%28%
990
16th to endNight
28%24%40%23%
1011
February1st to 15thNight
36%19%36%32%
901
16th to endNight
117%20%42%26%
789
March1st to 15thNight
29%26%36%24%
720
16th to endNight
311%22%39%21%
706
April1st to 15thNight
8%8%27%37%17%
468
16th to endNight
10%18%21%34%23%
360
May1st to 15thNight
18%13%24%28%15%
238
July16th to endNight
22%26%33%26%8%
45
August1st to 15thNight
21%29%21%35%9%
273
16th to endNight
27%111%25%28%5%
382
September1st to 15thNight
21%411%23%30%8%
525
16th to endNight
26%212%24%23%9%
681
October1st to 15thNight
23%39%24%28%10%
660
16th to endNight
16%310%29%27%12%
862
November1st to 15thNight
6%110%30%31%19%
905
16th to endNight
11%313%19%28%22%
965
December1st to 15thNight
3112%28%28%25%
990
16th to endNight
48%20%36%28%
1056
Page generated at 2017-09-22 06:35:34. Version ac04

Copyright 2017 A. Danko


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