Iroquois Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Iroquois Falls clear sky chart from 2005-11-05 to 2024-10-14.

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	16% 12% 4 9% 6% 5% 5% 4 5% 6% 27%	101628
	Night	15% 14% 5% 11% 6% 5% 5% 4 5% 6% 25%	97028
Transparency	Day	57% 5% 11% 19% 8% 1	101364
	Night	61% 5% 10% 17% 7% 1	96916
Seeing	Day	22% 11% 29% 25% 11% 3	15269
	Night	23% 8% 28% 29% 10% 1	24247

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	13% 24% 8% 12% 8% 7% 6% 4 6% 5% 9%	2208
	11th to 20th	Day	7% 15% 8% 19% 9% 5% 7% 4 5% 6% 16%	2210
	21st to end	Day	10% 24% 9% 14% 7% 7% 5% 3 6% 4 12%	2794
February	1st to 10th	Day	7% 15% 6% 11% 9% 8% 8% 4 7% 7% 18%	1710
	11th to 20th	Day	9% 18% 6% 11% 7% 6% 6% 5% 6% 6% 20%	1663
	21st to end	Day	9% 17% 7% 11% 6% 7% 6% 4 5% 6% 21%	1437
March	1st to 10th	Day	15% 14% 4 10% 6% 5% 6% 5% 5% 6% 24%	3301
	11th to 20th	Day	10% 19% 7% 15% 7% 4 4 3 4 5% 23%	3480
	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	27% 19% 4 9% 5% 5% 4 2 3 4 18%	1830
	21st to end	Day	24% 21% 6% 11% 6% 5% 4 2 3 3 14%	1829
November	1st to 10th	Day	21% 19% 7% 12% 5% 4 5% 2 4 5% 17%	1486
	11th to 20th	Day	19% 20% 8% 12% 8% 6% 4 3 3 4 12%	1520
	21st to end	Day	20% 23% 5% 16% 7% 6% 4 3 4 3 10%	1520
December	1st to 10th	Day	14% 23% 6% 16% 6% 5% 6% 3 4 5% 13%	1359
	11th to 20th	Day	13% 17% 6% 13% 8% 6% 4 4 5% 5% 18%	1671
	21st to end	Day	16% 23% 10% 19% 9% 4 4 2 3 3 8%	2431
January	1st to 10th	Night	12% 17% 8% 15% 8% 8% 7% 4 5% 5% 11%	4748
	11th to 20th	Night	9% 16% 7% 16% 8% 6% 8% 5% 6% 7% 12%	4760
	21st to end	Night	10% 22% 10% 14% 7% 8% 5% 3 4 5% 13%	4867
February	1st to 10th	Night	7% 15% 5% 9% 11% 8% 8% 5% 6% 7% 18%	2470
	11th to 20th	Night	10% 16% 6% 12% 7% 7% 6% 3 5% 7% 21%	2403
	21st to end	Night	9% 17% 6% 13% 8% 6% 6% 4 5% 6% 20%	2017
March	1st to 10th	Night	17% 15% 4 10% 6% 5% 4 3 4 5% 28%	3538
	11th to 20th	Night	13% 16% 6% 16% 7% 5% 3 3 4 4 22%	3479
	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% 4 9% 5% 4 5% 2 4 4 18%	2203
	21st to end	Night	21% 20% 4 10% 5% 5% 3 4 4 5% 19%	2523
November	1st to 10th	Night	18% 18% 6% 11% 7% 5% 5% 3 4 4 19%	2592
	11th to 20th	Night	22% 18% 6% 14% 7% 6% 4 3 3 3 14%	2660
	21st to end	Night	20% 20% 6% 16% 8% 5% 5% 3 3 4 11%	2660
December	1st to 10th	Night	14% 21% 7% 15% 9% 6% 5% 3 4 4 11%	2820
	11th to 20th	Night	15% 20% 6% 13% 9% 6% 6% 4 5% 4 12%	3526
	21st to end	Night	19% 22% 7% 15% 8% 5% 4 3 3 4 10%	5236

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	78% 4 9% 7% 2	2209
	11th to 20th	Day	68% 4 8% 15% 4	2210
	21st to end	Day	75% 4 5% 11% 5%	2794
February	1st to 10th	Day	64% 5% 9% 16% 5%	1710
	11th to 20th	Day	63% 5% 9% 15% 7%	1672
	21st to end	Day	63% 3 9% 18% 7%	1437
March	1st to 10th	Day	59% 7% 10% 18% 6%	3304
	11th to 20th	Day	65% 3 8% 16% 6% 1	3480
	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	57% 3 14% 19% 6%	1900
	11th to 20th	Day	72% 4 7% 14% 3	1831
	21st to end	Day	77% 4 7% 9% 3	1829
November	1st to 10th	Day	71% 6% 11% 9% 4	1486
	11th to 20th	Day	79% 3 7% 9% 2	1520
	21st to end	Day	81% 3 8% 6% 1	1520
December	1st to 10th	Day	74% 5% 9% 9% 3 1	1359
	11th to 20th	Day	68% 3 9% 16% 4	1671
	21st to end	Day	83% 2 6% 7% 2	2431
January	1st to 10th	Night	74% 5% 11% 8% 1	4748
	11th to 20th	Night	70% 5% 9% 14% 3	4760
	21st to end	Night	75% 4 7% 11% 4	4867
February	1st to 10th	Night	63% 6% 11% 13% 8%	2470
	11th to 20th	Night	64% 3 11% 16% 6%	2405
	21st to end	Night	65% 3 8% 15% 8% 1	2017
March	1st to 10th	Night	60% 4 9% 17% 9% 1	3548
	11th to 20th	Night	66% 4 7% 14% 8% 1	3480
	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% 5% 14% 20% 7%	2280
	11th to 20th	Night	71% 4 8% 13% 3	2207
	21st to end	Night	67% 5% 11% 12% 4	2523
November	1st to 10th	Night	69% 5% 12% 11% 3	2592
	11th to 20th	Night	75% 4 9% 8% 3	2660
	21st to end	Night	79% 3 9% 7% 2	2660
December	1st to 10th	Night	78% 4 8% 7% 3	2820
	11th to 20th	Night	74% 4 8% 11% 3	3525
	21st to end	Night	80% 4 6% 7% 3	5236

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	27% 9% 37% 18% 7% 2	180
	11th to 20th	Day	11% 14% 32% 32% 11% 1	180
	21st to end	Day	18% 7% 34% 32% 8% 1	285
February	1st to 10th	Day	16% 16% 36% 23% 8% 1	270
	11th to 20th	Day	17% 10% 39% 26% 5% 3	270
	21st to end	Day	21% 19% 41% 16% 3	225
March	1st to 10th	Day	17% 11% 37% 26% 7% 1	376
	11th to 20th	Day	21% 13% 27% 29% 7% 3	460
	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	35% 13% 31% 16% 3 2	462
	21st to end	Day	30% 13% 31% 20% 5% 1	348
November	1st to 10th	Day	36% 17% 31% 14% 2 1	180
	11th to 20th	Day	28% 19% 27% 21% 4 1	180
	21st to end	Day	36% 16% 31% 12% 4 1	180
December	1st to 10th	Day	24% 13% 29% 21% 10% 4	180
	11th to 20th	Day	21% 16% 38% 17% 7% 1	180
	21st to end	Day	28% 9% 37% 15% 8% 4	198
January	1st to 10th	Night	23% 8% 34% 25% 8% 1	950
	11th to 20th	Night	22% 7% 28% 32% 10% 1	950
	21st to end	Night	18% 6% 24% 33% 17% 2	1004
February	1st to 10th	Night	16% 8% 31% 32% 11% 1	760
	11th to 20th	Night	18% 8% 31% 33% 10% 1	743
	21st to end	Night	18% 9% 35% 26% 11%	628
March	1st to 10th	Night	18% 9% 33% 31% 8% 1	760
	11th to 20th	Night	22% 10% 31% 30% 7% 1	760
	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	37% 8% 29% 19% 5% 2	735
	21st to end	Night	32% 9% 25% 26% 7% 1	792
November	1st to 10th	Night	29% 9% 32% 25% 5% 1	740
	11th to 20th	Night	31% 11% 30% 20% 7% 1	760
	21st to end	Night	31% 11% 35% 18% 4 1	760
December	1st to 10th	Night	25% 11% 29% 25% 9% 1	920
	11th to 20th	Night	24% 9% 30% 27% 10% 1	950
	21st to end	Night	29% 8% 25% 25% 10% 3	1045

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