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 2025-03-12.

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% 5% 10% 6% 5% 5% 4 5% 6% 26%	108464
	Night	14% 15% 6% 12% 7% 5% 5% 4 5% 5% 23%	110688
Transparency	Day	58% 4 11% 19% 7% 1	111951
	Night	62% 4 10% 16% 7% 1	115364
Seeing	Day	22% 11% 29% 25% 10% 3	15650
	Night	23% 8% 29% 29% 10% 1	24901

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	9% 23% 10% 20% 8% 6% 6% 3 4 3 8%	3158
	11th to 20th	Day	6% 17% 9% 19% 8% 5% 6% 4 8% 6% 12%	3133
	21st to end	Day	7% 18% 8% 15% 7% 8% 8% 4 6% 5% 14%	4018
February	1st to 10th	Day	7% 15% 5% 11% 10% 7% 8% 4 7% 7% 18%	1800
	11th to 20th	Day	9% 19% 7% 11% 8% 6% 6% 5% 6% 6% 19%	1753
	21st to end	Day	9% 17% 6% 11% 6% 7% 6% 4 5% 7% 21%	1510
March	1st to 10th	Day	15% 14% 4 10% 6% 5% 6% 5% 5% 6% 23%	3407
	11th to 20th	Day	10% 19% 7% 15% 7% 5% 4 3 4 5% 23%	3491
	21st to end	Day	11% 14% 4 12% 6% 7% 6% 4 5% 6% 26%	3815
April	1st to 10th	Day	18% 15% 4 11% 6% 5% 5% 3 4 6% 23%	2287
	11th to 20th	Day	18% 13% 5% 8% 5% 4 4 3 5% 6% 29%	2442
	21st to end	Day	18% 11% 4 9% 6% 5% 4 3 4 6% 32%	2470
May	1st to 10th	Day	17% 11% 3 8% 5% 5% 4 3 5% 6% 32%	4295
	11th to 20th	Day	15% 9% 3 9% 5% 5% 5% 4 6% 7% 31%	4398
	21st to end	Day	19% 10% 2 6% 4 4 4 4 5% 7% 34%	5174
June	1st to 10th	Day	20% 8% 3 7% 6% 5% 5% 5% 6% 7% 29%	2850
	11th to 20th	Day	15% 8% 3 7% 4 4 5% 4 6% 7% 36%	2850
	21st to end	Day	18% 8% 3 8% 6% 5% 5% 4 6% 7% 31%	2850
July	1st to 10th	Day	18% 8% 3 7% 6% 5% 5% 5% 7% 8% 29%	4760
	11th to 20th	Day	14% 7% 3 7% 5% 5% 5% 5% 6% 9% 36%	4760
	21st to end	Day	16% 8% 3 7% 5% 5% 4 4 6% 8% 35%	5132
August	1st to 10th	Day	11% 7% 3 7% 6% 6% 5% 4 6% 9% 37%	4107
	11th to 20th	Day	16% 8% 3 8% 5% 5% 4 4 6% 7% 36%	4044
	21st to end	Day	15% 7% 3 7% 4 5% 4 4 6% 9% 38%	4532
September	1st to 10th	Day	19% 8% 3 6% 5% 5% 4 4 5% 6% 34%	2297
	11th to 20th	Day	22% 8% 2 7% 4 4 4 3 5% 8% 32%	2136
	21st to end	Day	24% 11% 3 7% 5% 4 3 3 3 6% 33%	2080
October	1st to 10th	Day	22% 13% 4 7% 4 4 3 2 4 6% 30%	1900
	11th to 20th	Day	26% 19% 5% 9% 5% 4 4 2 3 4 19%	1900
	21st to end	Day	24% 21% 6% 11% 6% 5% 4 2 3 3 14%	1930
November	1st to 10th	Day	21% 19% 7% 12% 4 4 5% 2 4 5% 17%	1566
	11th to 20th	Day	19% 21% 9% 13% 8% 6% 4 3 3 4 11%	1600
	21st to end	Day	20% 24% 5% 16% 7% 6% 4 3 3 3 10%	1600
December	1st to 10th	Day	12% 21% 9% 23% 9% 4 4 3 3 3 8%	2322
	11th to 20th	Day	11% 20% 6% 13% 8% 9% 4 4 4 5% 17%	2621
	21st to end	Day	17% 22% 9% 15% 7% 4 4 3 4 5% 10%	3476
January	1st to 10th	Night	9% 19% 11% 20% 8% 7% 6% 3 4 4 10%	6808
	11th to 20th	Night	9% 16% 8% 18% 8% 6% 6% 6% 8% 5% 9%	6772
	21st to end	Night	7% 18% 10% 14% 7% 6% 6% 5% 5% 5% 17%	6951
February	1st to 10th	Night	7% 14% 5% 10% 12% 8% 8% 5% 6% 7% 18%	2600
	11th to 20th	Night	9% 16% 6% 13% 7% 7% 6% 3 5% 7% 20%	2533
	21st to end	Night	9% 17% 6% 13% 8% 6% 6% 4 5% 6% 20%	2119
March	1st to 10th	Night	17% 15% 4 10% 6% 5% 5% 3 4 5% 27%	3652
	11th to 20th	Night	13% 16% 6% 16% 7% 5% 3 3 4 4 22%	3497
	21st to end	Night	13% 12% 6% 14% 6% 5% 5% 3 5% 5% 27%	3817
April	1st to 10th	Night	16% 14% 5% 10% 6% 4 5% 3 5% 5% 27%	1909
	11th to 20th	Night	17% 10% 4 8% 6% 5% 5% 4 6% 5% 30%	1687
	21st to end	Night	20% 10% 4 8% 4 4 4 3 4 5% 35%	1710
May	1st to 10th	Night	18% 9% 3 8% 5% 5% 4 4 5% 5% 33%	2646
	11th to 20th	Night	14% 8% 3 8% 4 4 5% 5% 7% 8% 34%	2495
	21st to end	Night	16% 9% 3 6% 4 4 5% 5% 6% 6% 36%	2411
June	1st to 10th	Night	21% 8% 3 7% 5% 4 4 3 7% 7% 31%	1330
	11th to 20th	Night	15% 6% 2 7% 5% 5% 4 4 5% 8% 39%	1330
	21st to end	Night	18% 9% 3 4 5% 5% 5% 3 6% 8% 34%	1330
July	1st to 10th	Night	16% 7% 3 7% 5% 3 5% 3 5% 7% 39%	2210
	11th to 20th	Night	15% 10% 3 6% 5% 5% 5% 4 5% 7% 35%	2210
	21st to end	Night	13% 10% 3 6% 5% 4 4 4 6% 7% 38%	2429
August	1st to 10th	Night	8% 6% 3 7% 5% 6% 5% 4 6% 9% 42%	2819
	11th to 20th	Night	14% 10% 3 7% 5% 4 4 4 4 7% 38%	2785
	21st to end	Night	13% 7% 2 5% 4 4 4 3 5% 6% 47%	3124
September	1st to 10th	Night	18% 7% 3 7% 3 3 5% 3 5% 7% 39%	1863
	11th to 20th	Night	20% 9% 3 6% 4 3 3 3 4 8% 35%	2042
	21st to end	Night	22% 9% 3 7% 4 3 3 4 4 6% 35%	2099
October	1st to 10th	Night	19% 12% 3 7% 6% 5% 4 4 5% 6% 30%	2280
	11th to 20th	Night	26% 18% 5% 9% 5% 4 5% 2 4 4 19%	2280
	21st to end	Night	21% 20% 4 10% 5% 5% 3 4 4 5% 19%	2664
November	1st to 10th	Night	19% 18% 5% 11% 6% 5% 5% 3 4 4 18%	2732
	11th to 20th	Night	22% 18% 6% 14% 7% 6% 4 3 3 3 14%	2800
	21st to end	Night	20% 21% 7% 16% 7% 5% 5% 3 3 4 11%	2800
December	1st to 10th	Night	11% 25% 9% 19% 10% 7% 4 3 3 2 7%	4866
	11th to 20th	Night	12% 18% 7% 14% 10% 8% 6% 4 4 4 12%	5586
	21st to end	Night	20% 22% 7% 12% 6% 5% 4 3 5% 4 13%	7502

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% 5% 3 1	3159
	11th to 20th	Day	70% 3 6% 14% 6%	3160
	21st to end	Day	71% 3 5% 14% 5% 1	4018
February	1st to 10th	Day	64% 5% 9% 17% 5%	1800
	11th to 20th	Day	64% 4 9% 15% 7%	1762
	21st to end	Day	63% 3 9% 18% 7%	1510
March	1st to 10th	Day	59% 7% 10% 17% 7%	3410
	11th to 20th	Day	65% 3 8% 16% 6% 1	3491
	21st to end	Day	59% 4 7% 16% 12% 2	3815
April	1st to 10th	Day	62% 4 7% 16% 10%	2287
	11th to 20th	Day	55% 4 9% 21% 11% 1	2442
	21st to end	Day	55% 4 9% 18% 12% 3	2470
May	1st to 10th	Day	52% 5% 10% 19% 12% 2	4307
	11th to 20th	Day	49% 7% 13% 21% 10% 1	4402
	21st to end	Day	48% 6% 11% 19% 13% 2	5174
June	1st to 10th	Day	53% 6% 10% 21% 10% 1	2850
	11th to 20th	Day	45% 6% 10% 24% 14% 1	2850
	21st to end	Day	51% 5% 12% 21% 10% 1	2850
July	1st to 10th	Day	50% 5% 14% 24% 6%	4686
	11th to 20th	Day	44% 5% 18% 22% 10% 1	4679
	21st to end	Day	46% 5% 13% 29% 7%	4969
August	1st to 10th	Day	44% 5% 16% 27% 7%	4093
	11th to 20th	Day	47% 6% 13% 28% 5% 1	4083
	21st to end	Day	43% 4 17% 28% 7% 1	4531
September	1st to 10th	Day	49% 5% 15% 21% 9%	2297
	11th to 20th	Day	52% 5% 18% 20% 5%	2136
	21st to end	Day	55% 4 11% 22% 7%	2080
October	1st to 10th	Day	61% 3 14% 18% 5%	3160
	11th to 20th	Day	63% 3 10% 20% 4	3140
	21st to end	Day	74% 3 10% 7% 6%	3155
November	1st to 10th	Day	71% 5% 11% 9% 4	1566
	11th to 20th	Day	79% 3 7% 9% 2	1600
	21st to end	Day	82% 3 8% 6% 1	1600
December	1st to 10th	Day	84% 3 6% 5% 2	2322
	11th to 20th	Day	71% 3 10% 13% 2	2621
	21st to end	Day	78% 2 5% 12% 2	3476
January	1st to 10th	Night	79% 3 8% 7% 2	6808
	11th to 20th	Night	73% 4 7% 11% 5%	6820
	21st to end	Night	70% 3 5% 16% 6%	6951
February	1st to 10th	Night	63% 5% 11% 13% 8%	2600
	11th to 20th	Night	66% 3 10% 15% 6%	2535
	21st to end	Night	65% 3 8% 15% 8% 1	2119
March	1st to 10th	Night	61% 4 8% 17% 9% 2	3662
	11th to 20th	Night	66% 4 7% 14% 8% 1	3498
	21st to end	Night	58% 5% 7% 14% 13% 2	3817
April	1st to 10th	Night	59% 4 8% 17% 12% 1	1909
	11th to 20th	Night	54% 4 7% 20% 12% 3	1687
	21st to end	Night	52% 4 7% 17% 18% 3	1710
May	1st to 10th	Night	51% 6% 8% 19% 14% 2	2653
	11th to 20th	Night	44% 8% 13% 23% 10% 1	2496
	21st to end	Night	45% 7% 11% 18% 17% 2	2412
June	1st to 10th	Night	50% 5% 9% 20% 13% 2	1330
	11th to 20th	Night	43% 5% 10% 24% 16% 2	1330
	21st to end	Night	47% 6% 12% 21% 12% 2	1330
July	1st to 10th	Night	44% 5% 13% 29% 8%	2175
	11th to 20th	Night	47% 5% 14% 21% 11% 1	2168
	21st to end	Night	47% 5% 14% 28% 7%	2352
August	1st to 10th	Night	38% 6% 16% 34% 6%	2809
	11th to 20th	Night	45% 6% 14% 31% 4	2812
	21st to end	Night	39% 4 14% 30% 11% 1	3124
September	1st to 10th	Night	45% 5% 16% 24% 9%	1863
	11th to 20th	Night	48% 5% 18% 23% 5%	2042
	21st to end	Night	50% 5% 15% 24% 6%	2099
October	1st to 10th	Night	55% 4 12% 23% 6%	3800
	11th to 20th	Night	64% 4 9% 20% 4	3779
	21st to end	Night	65% 5% 15% 11% 5%	4389
November	1st to 10th	Night	69% 5% 11% 11% 3	2732
	11th to 20th	Night	75% 4 9% 9% 3	2800
	21st to end	Night	80% 3 8% 7% 2	2800
December	1st to 10th	Night	85% 3 5% 5% 2	4866
	11th to 20th	Night	76% 3 7% 10% 5%	5585
	21st to end	Night	75% 3 6% 11% 4	7502

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% 10% 39% 19% 7% 2	200
	11th to 20th	Day	11% 13% 31% 33% 11% 1	200
	21st to end	Day	17% 8% 35% 30% 9% 1	317
February	1st to 10th	Day	16% 17% 38% 21% 7% 2	300
	11th to 20th	Day	17% 11% 40% 26% 4 2	300
	21st to end	Day	22% 17% 40% 18% 2	249
March	1st to 10th	Day	18% 11% 38% 25% 7% 1	412
	11th to 20th	Day	21% 13% 27% 28% 7% 3	464
	21st to end	Day	22% 12% 31% 26% 7% 2	506
April	1st to 10th	Day	19% 12% 32% 25% 10% 2	460
	11th to 20th	Day	26% 12% 25% 25% 9% 3	452
	21st to end	Day	23% 15% 26% 21% 13% 3	460
May	1st to 10th	Day	24% 10% 27% 22% 14% 3	463
	11th to 20th	Day	20% 11% 31% 25% 8% 5%	487
	21st to end	Day	21% 11% 27% 30% 9% 2	723
June	1st to 10th	Day	24% 9% 31% 26% 10% 1	680
	11th to 20th	Day	20% 10% 31% 25% 12% 2	680
	21st to end	Day	19% 9% 25% 29% 15% 3	680
July	1st to 10th	Day	17% 8% 31% 30% 10% 4	671
	11th to 20th	Day	16% 9% 27% 31% 14% 3	668
	21st to end	Day	16% 7% 28% 28% 16% 5%	721
August	1st to 10th	Day	18% 8% 22% 31% 15% 6%	486
	11th to 20th	Day	18% 6% 20% 30% 19% 7%	479
	21st to end	Day	20% 8% 24% 26% 14% 7%	539
September	1st to 10th	Day	21% 10% 29% 19% 15% 6%	490
	11th to 20th	Day	26% 7% 23% 29% 12% 4	490
	21st to end	Day	31% 9% 23% 22% 13% 2	490
October	1st to 10th	Day	27% 12% 26% 21% 10% 3	490
	11th to 20th	Day	36% 12% 31% 16% 3 1	490
	21st to end	Day	31% 15% 31% 18% 4 1	383
November	1st to 10th	Day	35% 18% 31% 14% 2 1	200
	11th to 20th	Day	30% 19% 28% 20% 4 1	200
	21st to end	Day	38% 15% 30% 13% 4 1	200
December	1st to 10th	Day	22% 14% 31% 21% 10% 4	200
	11th to 20th	Day	22% 15% 39% 17% 8% 1	200
	21st to end	Day	30% 9% 36% 15% 7% 3	220
January	1st to 10th	Night	23% 8% 35% 25% 8% 1	1000
	11th to 20th	Night	22% 7% 28% 31% 11% 1	1000
	21st to end	Night	18% 7% 25% 33% 16% 2	1056
February	1st to 10th	Night	16% 9% 32% 32% 11% 1	800
	11th to 20th	Night	18% 8% 32% 32% 9% 1	783
	21st to end	Night	18% 9% 35% 26% 11%	660
March	1st to 10th	Night	19% 9% 33% 30% 8% 1	800
	11th to 20th	Night	22% 10% 31% 30% 7% 1	767
	21st to end	Night	19% 8% 32% 31% 9% 1	836
April	1st to 10th	Night	24% 10% 30% 28% 8% 1	726
	11th to 20th	Night	21% 8% 30% 30% 10% 1	563
	21st to end	Night	24% 8% 28% 29% 10% 1	570
May	1st to 10th	Night	20% 4 34% 32% 10%	461
	11th to 20th	Night	23% 7% 29% 31% 9% 1	374
	21st to end	Night	19% 6% 32% 39% 5%	411
June	1st to 10th	Night	26% 8% 23% 32% 11%	380
	11th to 20th	Night	19% 7% 30% 36% 9%	380
	21st to end	Night	21% 3 24% 39% 12%	380
July	1st to 10th	Night	17% 4 26% 40% 11% 1	370
	11th to 20th	Night	18% 5% 21% 39% 16%	368
	21st to end	Night	16% 6% 20% 40% 17% 1	416
August	1st to 10th	Night	17% 5% 23% 37% 17% 2	561
	11th to 20th	Night	17% 4 21% 37% 20% 2	564
	21st to end	Night	20% 5% 24% 31% 19% 2	627
September	1st to 10th	Night	22% 7% 27% 28% 15% 2	723
	11th to 20th	Night	26% 6% 24% 29% 12% 2	760
	21st to end	Night	26% 6% 24% 28% 15% 2	760
October	1st to 10th	Night	27% 7% 27% 29% 10% 1	760
	11th to 20th	Night	38% 8% 29% 19% 5% 2	760
	21st to end	Night	32% 9% 27% 25% 7% 1	836
November	1st to 10th	Night	29% 9% 31% 24% 5% 1	780
	11th to 20th	Night	31% 11% 30% 21% 7% 1	800
	21st to end	Night	31% 11% 35% 18% 4 1	800
December	1st to 10th	Night	24% 11% 30% 25% 9% 1	969
	11th to 20th	Night	23% 9% 31% 27% 10% 1	1000
	21st to end	Night	30% 8% 25% 24% 10% 3	1100

Page generated at 2025-03-09 08:08:48. Version ac07

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