Iroquois Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Iroquois Falls clear sky chart from 2005-11-06 to 2026-07-16.

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	15% 13% 4 10% 6% 5% 5% 4 5% 6% 27%	138406
	Night	14% 15% 6% 12% 7% 5% 5% 4 5% 5% 23%	134509
Transparency	Day	58% 4 11% 19% 8% 1	141843
	Night	62% 4 9% 17% 7% 1	139160
Seeing	Day	22% 11% 30% 24% 10% 3	17526
	Night	23% 8% 29% 29% 10% 1	26516

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	11% 22% 9% 18% 7% 6% 7% 5% 5% 4 7%	4094
	11th to 20th	Day	6% 18% 9% 20% 9% 5% 6% 4 7% 6% 11%	4083
	21st to end	Day	5% 14% 7% 16% 9% 9% 8% 5% 7% 5% 15%	5204
February	1st to 10th	Day	7% 15% 6% 12% 10% 7% 8% 5% 7% 7% 18%	1890
	11th to 20th	Day	9% 18% 7% 11% 8% 6% 6% 5% 6% 6% 19%	1843
	21st to end	Day	9% 17% 6% 11% 7% 7% 7% 4 5% 7% 21%	1583
March	1st to 10th	Day	16% 16% 4 9% 7% 5% 5% 5% 5% 6% 21%	4851
	11th to 20th	Day	16% 17% 6% 13% 7% 6% 4 3 4 5% 21%	5090
	21st to end	Day	12% 17% 4 12% 6% 7% 6% 4 4 5% 24%	5586
April	1st to 10th	Day	18% 15% 5% 12% 6% 4 5% 3 4 6% 23%	2529
	11th to 20th	Day	18% 14% 5% 8% 5% 4 3 3 5% 6% 29%	2702
	21st to end	Day	18% 12% 4 9% 6% 5% 4 3 4 5% 31%	2730
May	1st to 10th	Day	15% 15% 5% 9% 5% 5% 4 3 4 5% 31%	7995
	11th to 20th	Day	15% 10% 4 9% 4 4 4 4 6% 7% 33%	8221
	21st to end	Day	17% 9% 3 6% 4 4 4 4 5% 7% 37%	9691
June	1st to 10th	Day	19% 8% 3 7% 5% 5% 5% 5% 5% 7% 30%	3150
	11th to 20th	Day	15% 8% 3 7% 5% 4 5% 4 6% 8% 35%	3150
	21st to end	Day	18% 8% 3 7% 6% 5% 4 4 6% 7% 32%	3150
July	1st to 10th	Day	15% 7% 3 7% 6% 6% 5% 5% 8% 9% 29%	6969
	11th to 20th	Day	15% 6% 2 6% 5% 5% 6% 5% 6% 9% 34%	6896
	21st to end	Day	16% 7% 3 7% 4 5% 5% 4 7% 9% 34%	7384
August	1st to 10th	Day	11% 7% 3 7% 6% 6% 5% 4 6% 9% 37%	4237
	11th to 20th	Day	16% 8% 3 8% 5% 5% 4 4 6% 7% 35%	4174
	21st to end	Day	15% 7% 3 7% 4 5% 4 4 7% 9% 37%	4675
September	1st to 10th	Day	19% 8% 3 7% 5% 5% 4 4 5% 6% 33%	2418
	11th to 20th	Day	21% 8% 3 7% 4 4 4 3 5% 8% 33%	2248
	21st to end	Day	23% 10% 3 6% 5% 4 3 3 4 6% 33%	2189
October	1st to 10th	Day	22% 13% 4 7% 4 4 3 2 4 6% 30%	2000
	11th to 20th	Day	26% 19% 4 9% 5% 4 4 2 3 4 20%	2000
	21st to end	Day	23% 21% 6% 11% 6% 5% 4 2 3 3 15%	2031
November	1st to 10th	Day	20% 19% 7% 12% 5% 4 5% 2 4 5% 17%	1646
	11th to 20th	Day	19% 21% 9% 13% 8% 5% 4 3 3 4 11%	1680
	21st to end	Day	20% 24% 6% 16% 7% 5% 4 2 3 3 9%	1680
December	1st to 10th	Day	12% 21% 9% 22% 9% 5% 5% 3 3 3 8%	2393
	11th to 20th	Day	11% 20% 6% 13% 8% 9% 4 4 4 5% 16%	2691
	21st to end	Day	18% 22% 9% 15% 6% 4 4 3 4 5% 10%	3553
January	1st to 10th	Night	9% 18% 10% 20% 9% 7% 6% 4 5% 4 9%	8831
	11th to 20th	Night	8% 17% 8% 19% 8% 7% 7% 6% 7% 5% 9%	8832
	21st to end	Night	5% 14% 8% 15% 8% 8% 8% 6% 8% 5% 15%	8999
February	1st to 10th	Night	7% 14% 5% 10% 11% 9% 8% 5% 6% 7% 18%	2730
	11th to 20th	Night	9% 16% 6% 13% 7% 7% 6% 3 5% 7% 19%	2663
	21st to end	Night	9% 17% 6% 13% 8% 6% 6% 4 5% 6% 20%	2222
March	1st to 10th	Night	17% 17% 5% 11% 6% 4 5% 3 4 4 24%	5208
	11th to 20th	Night	17% 16% 6% 14% 8% 5% 3 3 4 4 19%	5089
	21st to end	Night	13% 14% 5% 14% 7% 6% 5% 3 4 5% 24%	5588
April	1st to 10th	Night	17% 14% 5% 10% 6% 5% 5% 3 4 5% 26%	2109
	11th to 20th	Night	17% 11% 4 9% 6% 5% 5% 4 5% 5% 30%	1867
	21st to end	Night	19% 11% 4 9% 5% 4 4 4 4 5% 33%	1890
May	1st to 10th	Night	15% 13% 5% 10% 5% 5% 5% 4 5% 5% 30%	4904
	11th to 20th	Night	13% 9% 3 7% 4 4 5% 4 6% 7% 37%	4639
	21st to end	Night	14% 9% 3 6% 4 4 4 4 5% 6% 40%	4514
June	1st to 10th	Night	21% 9% 3 7% 5% 4 4 3 7% 7% 32%	1470
	11th to 20th	Night	15% 6% 2 7% 5% 5% 4 4 5% 8% 38%	1470
	21st to end	Night	18% 8% 3 5% 5% 5% 5% 3 6% 8% 34%	1470
July	1st to 10th	Night	17% 7% 3 7% 4 4 5% 3 5% 7% 39%	3230
	11th to 20th	Night	16% 8% 3 6% 5% 5% 5% 4 5% 7% 37%	3195
	21st to end	Night	13% 8% 3 6% 4 4 4 4 6% 8% 40%	3486
August	1st to 10th	Night	8% 6% 3 7% 5% 5% 5% 4 6% 9% 42%	2909
	11th to 20th	Night	14% 10% 3 7% 5% 4 4 4 4 7% 38%	2875
	21st to end	Night	13% 8% 3 5% 4 4 4 3 5% 6% 46%	3223
September	1st to 10th	Night	18% 7% 3 7% 4 3 5% 4 5% 7% 38%	1961
	11th to 20th	Night	19% 9% 3 6% 4 3 3 3 4 8% 37%	2150
	21st to end	Night	21% 9% 3 7% 4 3 3 4 4 6% 36%	2210
October	1st to 10th	Night	18% 11% 3 7% 6% 5% 5% 4 5% 6% 31%	2400
	11th to 20th	Night	26% 18% 4 9% 5% 4 5% 2 4 4 19%	2400
	21st to end	Night	20% 20% 5% 9% 5% 5% 3 4 4 5% 20%	2805
November	1st to 10th	Night	19% 19% 5% 12% 7% 5% 5% 3 4 4 18%	2872
	11th to 20th	Night	21% 18% 6% 15% 7% 5% 4 3 3 3 14%	2940
	21st to end	Night	21% 21% 7% 16% 7% 4 4 2 3 4 10%	2940
December	1st to 10th	Night	11% 25% 9% 18% 10% 7% 5% 3 3 2 7%	5015
	11th to 20th	Night	12% 18% 7% 14% 10% 8% 7% 4 4 4 12%	5736
	21st to end	Night	20% 22% 7% 12% 6% 5% 4 3 5% 4 13%	7667

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	1st to 10th	Day	82% 3 6% 6% 3	4095
	11th to 20th	Day	73% 3 5% 13% 6%	4110
	21st to end	Day	69% 3 6% 17% 5%	5204
February	1st to 10th	Day	65% 5% 9% 16% 5%	1890
	11th to 20th	Day	64% 4 9% 16% 7%	1852
	21st to end	Day	63% 3 9% 17% 8%	1583
March	1st to 10th	Day	63% 5% 7% 13% 11% 1	4854
	11th to 20th	Day	68% 3 9% 13% 7% 1	5090
	21st to end	Day	63% 3 6% 17% 10% 1	5586
April	1st to 10th	Day	63% 4 7% 16% 10%	2529
	11th to 20th	Day	55% 4 9% 21% 11% 1	2702
	21st to end	Day	55% 4 9% 18% 12% 2	2730
May	1st to 10th	Day	56% 4 6% 15% 17% 2	8004
	11th to 20th	Day	49% 5% 13% 21% 9% 3	8225
	21st to end	Day	46% 4 10% 22% 15% 3	9692
June	1st to 10th	Day	52% 5% 10% 21% 11% 1	3150
	11th to 20th	Day	47% 6% 10% 23% 14% 1	3150
	21st to end	Day	50% 5% 12% 22% 10% 1	3150
July	1st to 10th	Day	48% 5% 14% 25% 7%	6896
	11th to 20th	Day	45% 5% 19% 23% 8% 1	6815
	21st to end	Day	46% 5% 14% 28% 7%	7172
August	1st to 10th	Day	44% 5% 17% 27% 7%	4223
	11th to 20th	Day	48% 6% 13% 27% 5%	4213
	21st to end	Day	43% 4 17% 28% 7% 1	4674
September	1st to 10th	Day	50% 5% 15% 21% 8%	2418
	11th to 20th	Day	51% 5% 17% 22% 5%	2248
	21st to end	Day	54% 4 11% 22% 7%	2189
October	1st to 10th	Day	60% 3 14% 18% 5%	3260
	11th to 20th	Day	63% 3 9% 20% 4	3240
	21st to end	Day	73% 3 10% 8% 6%	3256
November	1st to 10th	Day	70% 5% 11% 10% 4	1646
	11th to 20th	Day	80% 3 7% 9% 2	1680
	21st to end	Day	83% 3 8% 6% 1	1680
December	1st to 10th	Day	83% 3 6% 6% 2	2393
	11th to 20th	Day	72% 3 10% 13% 2	2691
	21st to end	Day	78% 2 5% 12% 2	3553
January	1st to 10th	Night	79% 3 8% 9% 2	8831
	11th to 20th	Night	75% 3 6% 10% 5%	8880
	21st to end	Night	68% 3 5% 18% 6%	8999
February	1st to 10th	Night	64% 5% 10% 13% 8%	2730
	11th to 20th	Night	66% 3 10% 15% 6%	2665
	21st to end	Night	65% 3 8% 16% 8%	2222
March	1st to 10th	Night	66% 3 6% 13% 9% 4	5218
	11th to 20th	Night	70% 4 6% 12% 7% 1	5090
	21st to end	Night	62% 4 6% 15% 11% 2	5588
April	1st to 10th	Night	60% 4 7% 17% 11% 1	2109
	11th to 20th	Night	55% 4 7% 19% 12% 2	1867
	21st to end	Night	54% 3 8% 16% 17% 2	1890
May	1st to 10th	Night	56% 4 8% 18% 14% 1	4911
	11th to 20th	Night	44% 6% 13% 23% 13% 2	4640
	21st to end	Night	43% 5% 10% 21% 18% 2	4515
June	1st to 10th	Night	50% 5% 9% 20% 14% 2	1470
	11th to 20th	Night	44% 5% 10% 24% 15% 1	1470
	21st to end	Night	47% 6% 11% 22% 12% 2	1470
July	1st to 10th	Night	46% 4 11% 29% 9%	3195
	11th to 20th	Night	46% 4 14% 26% 10%	3153
	21st to end	Night	43% 5% 17% 30% 5%	3384
August	1st to 10th	Night	38% 6% 16% 34% 6%	2899
	11th to 20th	Night	45% 5% 14% 31% 4	2902
	21st to end	Night	40% 4 14% 30% 11% 1	3223
September	1st to 10th	Night	46% 5% 15% 24% 9%	1961
	11th to 20th	Night	47% 5% 18% 25% 5%	2150
	21st to end	Night	49% 5% 15% 25% 5%	2210
October	1st to 10th	Night	54% 4 13% 23% 6%	3920
	11th to 20th	Night	64% 3 9% 20% 4	3899
	21st to end	Night	64% 5% 15% 12% 5%	4530
November	1st to 10th	Night	70% 4 11% 11% 3	2872
	11th to 20th	Night	76% 4 9% 8% 3	2940
	21st to end	Night	81% 3 8% 6% 2	2940
December	1st to 10th	Night	85% 3 5% 5% 2	5015
	11th to 20th	Night	76% 3 7% 10% 4	5735
	21st to end	Night	76% 3 6% 11% 4	7667

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	1st to 10th	Day	25% 9% 40% 19% 6% 1	220
	11th to 20th	Day	13% 13% 31% 32% 11% 1	220
	21st to end	Day	16% 7% 38% 30% 8% 1	349
February	1st to 10th	Day	17% 16% 35% 23% 7% 2	330
	11th to 20th	Day	17% 11% 40% 25% 5% 2	330
	21st to end	Day	21% 17% 40% 18% 3 1	273
March	1st to 10th	Day	20% 12% 38% 23% 6% 1	448
	11th to 20th	Day	23% 14% 28% 26% 6% 2	540
	21st to end	Day	22% 14% 32% 23% 7% 2	594
April	1st to 10th	Day	20% 14% 31% 23% 10% 2	540
	11th to 20th	Day	27% 12% 27% 24% 8% 3	532
	21st to end	Day	24% 14% 27% 20% 12% 2	540
May	1st to 10th	Day	25% 10% 28% 22% 13% 2	543
	11th to 20th	Day	21% 11% 33% 24% 7% 4	567
	21st to end	Day	22% 11% 27% 29% 9% 2	832
June	1st to 10th	Day	23% 9% 31% 26% 9% 1	780
	11th to 20th	Day	21% 11% 30% 24% 11% 2	780
	21st to end	Day	20% 9% 26% 28% 14% 4	780
July	1st to 10th	Day	16% 9% 32% 29% 10% 4	771
	11th to 20th	Day	17% 11% 28% 29% 13% 2	744
	21st to end	Day	16% 7% 29% 28% 15% 5%	775
August	1st to 10th	Day	17% 8% 24% 30% 15% 6%	526
	11th to 20th	Day	18% 8% 20% 29% 19% 7%	519
	21st to end	Day	21% 8% 25% 26% 14% 7%	583
September	1st to 10th	Day	22% 10% 29% 20% 14% 5%	530
	11th to 20th	Day	25% 6% 23% 29% 12% 4	530
	21st to end	Day	29% 10% 23% 22% 14% 2	530
October	1st to 10th	Day	26% 12% 28% 21% 10% 3	530
	11th to 20th	Day	35% 12% 31% 16% 4 1	530
	21st to end	Day	30% 14% 30% 20% 6% 1	418
November	1st to 10th	Day	34% 19% 30% 15% 2	220
	11th to 20th	Day	28% 19% 27% 20% 4 1	220
	21st to end	Day	38% 15% 30% 12% 4 1	220
December	1st to 10th	Day	21% 14% 33% 20% 9% 3	220
	11th to 20th	Day	22% 15% 37% 17% 7% 1	220
	21st to end	Day	31% 8% 38% 14% 7% 3	242
January	1st to 10th	Night	22% 8% 36% 25% 8% 1	1050
	11th to 20th	Night	22% 7% 28% 32% 11% 1	1050
	21st to end	Night	17% 7% 26% 32% 16% 2	1109
February	1st to 10th	Night	15% 9% 32% 32% 11% 1	840
	11th to 20th	Night	18% 9% 32% 32% 9%	823
	21st to end	Night	18% 10% 35% 26% 11%	692
March	1st to 10th	Night	20% 10% 33% 29% 8% 1	840
	11th to 20th	Night	23% 10% 31% 29% 7%	840
	21st to end	Night	19% 8% 34% 29% 9% 1	924
April	1st to 10th	Night	24% 11% 31% 27% 7%	802
	11th to 20th	Night	22% 9% 30% 30% 9% 1	623
	21st to end	Night	24% 8% 29% 28% 10% 1	630
May	1st to 10th	Night	19% 5% 34% 32% 10%	509
	11th to 20th	Night	22% 8% 29% 31% 9% 1	414
	21st to end	Night	18% 7% 32% 37% 5%	455
June	1st to 10th	Night	26% 8% 25% 31% 11%	420
	11th to 20th	Night	20% 6% 30% 36% 8%	420
	21st to end	Night	21% 3 25% 37% 13%	420
July	1st to 10th	Night	17% 5% 27% 40% 11% 1	410
	11th to 20th	Night	18% 6% 22% 38% 15%	398
	21st to end	Night	15% 6% 21% 39% 16% 1	438
August	1st to 10th	Night	16% 5% 23% 36% 17% 2	591
	11th to 20th	Night	16% 4 22% 36% 20% 2	594
	21st to end	Night	20% 5% 24% 30% 18% 2	660
September	1st to 10th	Night	22% 7% 27% 28% 15% 1	761
	11th to 20th	Night	25% 6% 24% 30% 13% 2	800
	21st to end	Night	25% 6% 24% 28% 15% 2	800
October	1st to 10th	Night	26% 7% 28% 29% 10% 1	800
	11th to 20th	Night	37% 8% 30% 19% 5% 2	800
	21st to end	Night	31% 9% 26% 26% 8% 1	880
November	1st to 10th	Night	29% 10% 31% 24% 5% 1	820
	11th to 20th	Night	30% 11% 31% 21% 7% 1	840
	21st to end	Night	32% 11% 34% 18% 4	840
December	1st to 10th	Night	24% 12% 30% 25% 8% 1	1018
	11th to 20th	Night	23% 8% 32% 26% 9% 1	1050
	21st to end	Night	30% 8% 25% 24% 10% 3	1155

Page generated at 2026-07-13 03:14:48. Version ac07

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