Igloolik
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Igloolik clear sky chart from 2005-11-06 to 2026-01-17.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	9% 10% 4 11% 7% 6% 6% 5% 7% 8% 27%	137330
	Night	4 8% 4 13% 9% 9% 9% 7% 10% 10% 17%	131290
Transparency	Day	52% 8% 16% 20% 5%	136822
	Night	55% 8% 16% 17% 4	131355
Seeing	Day	14% 2 10% 23% 31% 20%	20543
	Night	8% 2 11% 26% 34% 19%	24980

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	11th to 20th	Day	1 2 1 5% 10% 12% 4 6% 8% 8% 42%	156
	21st to end	Day	1 1 7% 9% 9% 8% 11% 17% 20% 18%	1351
February	1st to 10th	Day	1 3 3 10% 7% 12% 10% 11% 13% 15% 16%	938
	11th to 20th	Day	3 2 7% 12% 9% 12% 10% 12% 15% 19%	1259
	21st to end	Day	4 2 10% 8% 10% 10% 6% 11% 18% 20%	1252
March	1st to 10th	Day	1 6% 3 11% 12% 11% 9% 7% 13% 9% 18%	4057
	11th to 20th	Day	3 7% 5% 15% 12% 11% 9% 6% 9% 8% 15%	4833
	21st to end	Day	1 5% 3 10% 7% 8% 9% 9% 11% 12% 25%	5954
April	1st to 10th	Day	3 10% 5% 8% 6% 7% 6% 6% 7% 10% 30%	2620
	11th to 20th	Day	3 7% 4 9% 9% 10% 9% 6% 8% 8% 28%	2968
	21st to end	Day	4 12% 5% 14% 9% 9% 8% 4 5% 6% 24%	3285
May	1st to 10th	Day	4 9% 7% 18% 12% 8% 6% 4 5% 6% 22%	8186
	11th to 20th	Day	2 7% 5% 17% 12% 7% 7% 4 7% 8% 24%	9036
	21st to end	Day	6% 11% 7% 17% 7% 6% 5% 4 7% 8% 22%	11785
June	1st to 10th	Day	12% 14% 5% 9% 6% 5% 5% 5% 6% 7% 26%	4800
	11th to 20th	Day	15% 13% 5% 11% 6% 5% 4 4 5% 6% 28%	4800
	21st to end	Day	13% 10% 4 7% 6% 4 5% 4 6% 8% 33%	4800
July	1st to 10th	Day	15% 9% 3 8% 5% 5% 5% 4 7% 8% 30%	10880
	11th to 20th	Day	20% 8% 3 6% 5% 4 4 4 6% 7% 33%	10880
	21st to end	Day	10% 7% 3 6% 4 4 5% 4 6% 9% 43%	10248
August	1st to 10th	Day	10% 6% 2 6% 4 5% 6% 5% 8% 9% 39%	5947
	11th to 20th	Day	10% 8% 3 8% 6% 5% 5% 4 6% 6% 40%	5375
	21st to end	Day	15% 8% 3 8% 4 5% 5% 4 6% 7% 35%	5401
September	1st to 10th	Day	15% 10% 4 9% 5% 5% 4 3 5% 8% 34%	2660
	11th to 20th	Day	14% 17% 7% 13% 6% 4 5% 4 6% 6% 19%	2415
	21st to end	Day	20% 16% 8% 14% 5% 4 3 2 3 5% 19%	2132
October	1st to 10th	Day	14% 25% 9% 19% 5% 4 3 2 3 3 13%	3034
	11th to 20th	Day	14% 25% 10% 20% 7% 4 3 2 4 3 7%	2522
	21st to end	Day	6% 18% 7% 19% 12% 9% 6% 4 4 4 10%	2222
November	1st to 10th	Day	2 9% 4 15% 14% 16% 10% 6% 6% 5% 13%	916
	11th to 20th	Day	8% 14% 8% 16% 9% 10% 10% 5% 6% 4 9%	560
	21st to end	Day	5% 22% 3 14% 21% 2 9% 2 5% 7% 10%	58
January	1st to 10th	Night	1 4 4 11% 8% 10% 10% 8% 10% 14% 20%	11105
	11th to 20th	Night	1 4 3 11% 8% 9% 7% 6% 9% 15% 27%	10421
	21st to end	Night	2 1 5% 7% 10% 12% 11% 17% 17% 20%	9611
February	1st to 10th	Night	1 4 2 9% 8% 12% 12% 10% 15% 13% 15%	3462
	11th to 20th	Night	1 3 2 8% 10% 9% 11% 10% 14% 15% 18%	3028
	21st to end	Night	1 3 2 9% 10% 8% 11% 8% 13% 13% 21%	2375
March	1st to 10th	Night	5% 3 12% 13% 12% 10% 8% 10% 9% 17%	5794
	11th to 20th	Night	1 8% 6% 17% 11% 9% 9% 7% 10% 8% 14%	5126
	21st to end	Night	1 3 3 9% 8% 7% 9% 8% 10% 13% 30%	5021
April	1st to 10th	Night	2 10% 5% 10% 6% 5% 7% 6% 7% 11% 30%	1779
	11th to 20th	Night	4 8% 3 8% 8% 12% 11% 7% 7% 7% 25%	1384
	21st to end	Night	6% 10% 4 15% 11% 9% 8% 4 4 7% 21%	1114
May	1st to 10th	Night	4 9% 6% 21% 14% 10% 6% 4 5% 7% 14%	1804
	11th to 20th	Night	3 7% 5% 25% 12% 7% 8% 5% 5% 6% 18%	864
	21st to end	Night	25% 25% 25% 25%	4
July	21st to end	Night	7% 9% 3 8% 5% 5% 4 3 4 9% 43%	715
	August	1st to 10th	Night	11% 7% 4 7% 5% 5% 5% 4 6% 9% 39%	1203
11th to 20th		Night	11% 9% 3 10% 6% 5% 5% 3 5% 7% 37%	1692
21st to end		Night	16% 9% 3 7% 4 4 4 3 5% 9% 37%	2508
September	1st to 10th	Night	14% 14% 4 9% 6% 5% 3 3 5% 5% 32%	1740
	11th to 20th	Night	13% 19% 8% 10% 6% 6% 4 3 5% 6% 19%	1962
	21st to end	Night	18% 17% 9% 16% 5% 4 4 3 3 4 17%	2269
October	1st to 10th	Night	17% 23% 10% 20% 5% 3 3 2 3 3 11%	4144
	11th to 20th	Night	16% 22% 12% 19% 7% 4 3 2 3 3 10%	4617
	21st to end	Night	6% 15% 7% 25% 12% 10% 5% 3 4 4 7%	5586
November	1st to 10th	Night	2 7% 5% 15% 15% 17% 10% 5% 5% 6% 13%	3601
	11th to 20th	Night	7% 14% 7% 18% 11% 10% 9% 6% 5% 4 9%	4061
	21st to end	Night	5% 14% 6% 13% 10% 10% 11% 6% 8% 8% 9%	4793
December	1st to 10th	Night	1 6% 4 13% 12% 11% 18% 13% 12% 5% 6%	8080
	11th to 20th	Night	2 5% 3 11% 12% 11% 11% 10% 16% 10% 9%	9195
	21st to end	Night	1 5% 4 14% 11% 11% 9% 7% 12% 15% 13%	12232

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	11th to 20th	Day	37% 5% 45% 11% 3	156
	21st to end	Day	36% 9% 22% 22% 10%	1351
February	1st to 10th	Day	44% 12% 21% 21% 2	938
	11th to 20th	Day	43% 9% 22% 17% 9%	1265
	21st to end	Day	42% 7% 21% 18% 12%	1252
March	1st to 10th	Day	54% 7% 11% 20% 8%	4057
	11th to 20th	Day	61% 7% 10% 16% 6%	4835
	21st to end	Day	44% 6% 11% 25% 14%	5954
April	1st to 10th	Day	47% 7% 11% 22% 12% 1	2620
	11th to 20th	Day	49% 8% 10% 24% 9%	2968
	21st to end	Day	59% 7% 9% 18% 8%	3285
May	1st to 10th	Day	61% 7% 8% 15% 9%	8183
	11th to 20th	Day	54% 9% 10% 17% 10%	9040
	21st to end	Day	55% 12% 14% 16% 3	11786
June	1st to 10th	Day	54% 10% 14% 21% 2	4800
	11th to 20th	Day	56% 7% 13% 22% 2	4800
	21st to end	Day	47% 8% 19% 23% 3	4800
July	1st to 10th	Day	49% 7% 17% 24% 3	10761
	11th to 20th	Day	50% 7% 17% 24% 3	10745
	21st to end	Day	35% 8% 27% 28% 3	9956
August	1st to 10th	Day	38% 11% 30% 19% 2	5925
	11th to 20th	Day	42% 7% 23% 25% 3	5426
	21st to end	Day	46% 7% 27% 18% 1	5400
September	1st to 10th	Day	48% 10% 26% 15% 1	2660
	11th to 20th	Day	64% 8% 15% 11% 1	2415
	21st to end	Day	68% 7% 12% 12% 1	2132
October	1st to 10th	Day	76% 5% 8% 9% 1	3034
	11th to 20th	Day	81% 5% 10% 3 1	2522
	21st to end	Day	73% 9% 12% 5% 2	2222
November	1st to 10th	Day	64% 12% 16% 8%	916
	11th to 20th	Day	71% 5% 12% 10% 2	560
	21st to end	Day	72% 5% 9% 14%	58
January	1st to 10th	Night	46% 8% 16% 25% 6%	11105
	11th to 20th	Night	43% 7% 27% 22% 2	10487
	21st to end	Night	35% 9% 24% 24% 8%	9611
February	1st to 10th	Night	47% 9% 22% 19% 3	3462
	11th to 20th	Night	44% 9% 20% 20% 7%	3032
	21st to end	Night	43% 8% 18% 20% 10% 1	2375
March	1st to 10th	Night	58% 5% 11% 22% 5%	5794
	11th to 20th	Night	61% 7% 10% 16% 6%	5126
	21st to end	Night	40% 6% 13% 28% 13%	5021
April	1st to 10th	Night	45% 5% 14% 25% 10% 1	1779
	11th to 20th	Night	52% 8% 8% 22% 10%	1384
	21st to end	Night	60% 5% 7% 19% 7% 1	1114
May	1st to 10th	Night	65% 9% 7% 12% 7%	1804
	11th to 20th	Night	63% 6% 9% 13% 9%	864
	21st to end	Night	75% 25%	4
July	21st to end	Night	37% 7% 25% 28% 3	698
	August	1st to 10th	Night	42% 7% 28% 21% 2	1200
11th to 20th		Night	48% 6% 20% 22% 4	1707
21st to end		Night	44% 6% 30% 19%	2508
September	1st to 10th	Night	54% 8% 25% 12% 1	1740
	11th to 20th	Night	65% 8% 15% 12% 1	1962
	21st to end	Night	71% 6% 11% 11% 1	2269
October	1st to 10th	Night	78% 6% 8% 8%	4144
	11th to 20th	Night	80% 4 9% 5% 1	4617
	21st to end	Night	76% 9% 10% 5% 1	5586
November	1st to 10th	Night	64% 9% 16% 9% 1	3601
	11th to 20th	Night	71% 6% 13% 8% 1	4061
	21st to end	Night	65% 8% 13% 13% 1	4793
December	1st to 10th	Night	66% 10% 10% 13% 1	8080
	11th to 20th	Night	55% 11% 19% 14% 1	9195
	21st to end	Night	52% 6% 18% 17% 7%	12232

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	21st to end	Day	1 1 7% 30% 34% 27%	100
	February	1st to 10th	Day	1 4 25% 41% 28%	170
11th to 20th		Day	1 6% 22% 35% 37%	200
21st to end		Day	1 6% 24% 35% 33%	216
March	1st to 10th	Day	2 2 12% 22% 33% 29%	300
	11th to 20th	Day	3 1 10% 24% 31% 31%	433
	21st to end	Day	2 1 9% 23% 35% 31%	550
April	1st to 10th	Day	7% 3 8% 21% 29% 31%	500
	11th to 20th	Day	4 1 7% 21% 36% 31%	690
	21st to end	Day	8% 3 11% 24% 30% 24%	865
May	1st to 10th	Day	10% 2 9% 23% 33% 23%	903
	11th to 20th	Day	9% 2 12% 26% 32% 19%	1006
	21st to end	Day	12% 2 9% 20% 34% 23%	1435
June	1st to 10th	Day	15% 2 8% 23% 31% 21%	1330
	11th to 20th	Day	19% 2 10% 24% 28% 17%	1330
	21st to end	Day	16% 2 8% 26% 34% 14%	1330
July	1st to 10th	Day	11% 1 10% 26% 34% 18%	1306
	11th to 20th	Day	21% 3 9% 23% 29% 14%	1300
	21st to end	Day	16% 4 11% 21% 28% 21%	1208
August	1st to 10th	Day	16% 1 9% 23% 33% 17%	925
	11th to 20th	Day	19% 4 11% 21% 28% 18%	883
	21st to end	Day	20% 4 14% 24% 23% 16%	803
September	1st to 10th	Day	19% 3 10% 21% 33% 14%	550
	11th to 20th	Day	21% 3 10% 22% 26% 18%	530
	21st to end	Day	23% 3 11% 22% 30% 12%	530
October	1st to 10th	Day	24% 7% 17% 25% 22% 7%	395
	11th to 20th	Day	23% 8% 18% 20% 20% 12%	220
	21st to end	Day	12% 5% 11% 32% 29% 12%	242
November	1st to 10th	Day	3 3 8% 34% 38% 14%	220
	11th to 20th	Day	4 5% 15% 30% 30% 15%	73
January	1st to 10th	Night	4 1 10% 24% 37% 24%	1380
	11th to 20th	Night	2 1 7% 29% 40% 21%	1308
	21st to end	Night	2 1 9% 26% 40% 22%	1246
February	1st to 10th	Night	2 8% 23% 38% 29%	1100
	11th to 20th	Night	2 6% 22% 39% 31%	982
	21st to end	Night	1 1 9% 22% 41% 25%	825
March	1st to 10th	Night	3 2 9% 26% 35% 25%	800
	11th to 20th	Night	3 1 10% 30% 39% 18%	800
	21st to end	Night	2 1 11% 22% 42% 22%	777
April	1st to 10th	Night	7% 2 6% 27% 39% 18%	580
	11th to 20th	Night	8% 6% 27% 39% 21%	396
	21st to end	Night	10% 2 10% 25% 33% 21%	400
May	1st to 10th	Night	14% 2 10% 26% 32% 17%	322
	11th to 20th	Night	13% 16% 27% 25% 19%	75
July	21st to end	Night	17% 4 9% 25% 37% 8%	76
	August	1st to 10th	Night	19% 1 12% 26% 30% 12%	252
11th to 20th		Night	20% 3 11% 28% 30% 9%	396
21st to end		Night	28% 3 12% 24% 25% 9%	440
September	1st to 10th	Night	21% 4 13% 21% 33% 8%	560
	11th to 20th	Night	20% 3 11% 25% 27% 13%	715
	21st to end	Night	25% 4 11% 24% 26% 10%	800
October	1st to 10th	Night	24% 4 16% 24% 26% 7%	800
	11th to 20th	Night	23% 6% 18% 25% 21% 8%	838
	21st to end	Night	15% 3 11% 29% 31% 12%	1188
November	1st to 10th	Night	4 2 10% 30% 37% 17%	1135
	11th to 20th	Night	10% 4 16% 27% 29% 14%	1160
	21st to end	Night	9% 3 12% 23% 34% 19%	1351
December	1st to 10th	Night	4 2 13% 32% 29% 21%	1380
	11th to 20th	Night	4 1 15% 27% 32% 20%	1380
	21st to end	Night	3 1 11% 24% 37% 24%	1518

Page generated at 2026-01-14 00:14:29. Version ac07

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