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 2024-02-10.

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	17% 12% 5% 9% 7% 4 5% 5% 5% 6% 25%	77760
	Night	16% 14% 6% 10% 8% 4 5% 5% 5% 6% 23%	81245
Transparency	Day	59% 5% 11% 18% 7% 1	77445
	Night	63% 5% 10% 15% 6% 1	81095
Seeing	Day	22% 10% 28% 25% 11% 3	14234
	Night	23% 8% 28% 29% 11% 1	23493

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% 22% 9% 11% 9% 5% 7% 5% 5% 5% 9%	2208
	11th to 20th	Day	8% 14% 8% 16% 11% 4 6% 5% 5% 7% 16%	2210
	21st to end	Day	10% 22% 10% 12% 9% 5% 6% 4 5% 5% 12%	2794
February	1st to 10th	Day	8% 14% 6% 10% 11% 5% 9% 6% 6% 7% 18%	1701
	11th to 20th	Day	10% 17% 7% 10% 7% 4 6% 6% 6% 6% 20%	1573
	21st to end	Day	9% 15% 8% 10% 8% 4 8% 5% 5% 6% 22%	1354
March	1st to 10th	Day	12% 12% 5% 11% 8% 6% 6% 7% 5% 6% 22%	1897
	11th to 20th	Day	13% 15% 5% 9% 8% 4 6% 4 4 6% 28%	1980
	21st to end	Day	14% 13% 4 9% 7% 4 5% 5% 4 5% 30%	2178
April	1st to 10th	Day	19% 13% 5% 10% 7% 4 5% 4 4 6% 22%	2166
	11th to 20th	Day	18% 12% 5% 7% 5% 3 4 4 5% 6% 31%	2312
	21st to end	Day	17% 11% 4 8% 7% 4 5% 4 4 6% 32%	2340
May	1st to 10th	Day	17% 11% 5% 8% 7% 4 4 4 4 6% 29%	2443
	11th to 20th	Day	20% 10% 3 7% 5% 3 4 4 5% 7% 31%	2478
	21st to end	Day	19% 7% 3 6% 6% 3 5% 5% 6% 7% 33%	2908
June	1st to 10th	Day	21% 8% 3 6% 6% 3 5% 6% 5% 7% 30%	2700
	11th to 20th	Day	16% 7% 3 6% 5% 3 5% 5% 6% 8% 36%	2700
	21st to end	Day	18% 7% 3 6% 6% 4 5% 5% 6% 7% 32%	2700
July	1st to 10th	Day	18% 7% 3 5% 6% 3 5% 6% 6% 8% 33%	2700
	11th to 20th	Day	15% 6% 3 6% 6% 4 6% 6% 6% 10% 32%	2700
	21st to end	Day	16% 7% 4 7% 6% 4 6% 5% 6% 9% 30%	2923
August	1st to 10th	Day	15% 7% 4 7% 8% 4 6% 6% 5% 8% 30%	2330
	11th to 20th	Day	17% 7% 3 6% 7% 4 5% 5% 6% 7% 33%	2303
	21st to end	Day	16% 6% 4 7% 5% 4 5% 5% 6% 8% 33%	2574
September	1st to 10th	Day	19% 8% 3 6% 5% 4 4 5% 5% 7% 34%	2177
	11th to 20th	Day	23% 8% 3 6% 6% 3 4 5% 4 8% 30%	2024
	21st to end	Day	24% 10% 4 6% 6% 3 3 4 3 6% 32%	1971
October	1st to 10th	Day	23% 13% 4 6% 4 3 3 3 4 6% 31%	1800
	11th to 20th	Day	28% 19% 5% 8% 6% 3 4 3 3 4 18%	1800
	21st to end	Day	25% 20% 6% 9% 8% 4 4 3 3 3 14%	1829
November	1st to 10th	Day	21% 18% 8% 12% 5% 3 4 4 4 5% 17%	1486
	11th to 20th	Day	20% 18% 9% 12% 10% 4 5% 3 3 4 12%	1520
	21st to end	Day	20% 22% 5% 15% 8% 4 5% 4 3 3 10%	1520
December	1st to 10th	Day	15% 20% 8% 14% 7% 4 5% 5% 4 5% 13%	1359
	11th to 20th	Day	14% 16% 6% 11% 10% 4 5% 5% 5% 5% 18%	1671
	21st to end	Day	16% 22% 10% 16% 12% 3 4 3 2 4 8%	2431
January	1st to 10th	Night	12% 16% 8% 14% 9% 6% 8% 5% 5% 5% 11%	4748
	11th to 20th	Night	10% 15% 7% 14% 10% 5% 7% 7% 6% 7% 13%	4760
	21st to end	Night	10% 21% 10% 12% 9% 6% 6% 4 4 5% 13%	4867
February	1st to 10th	Night	8% 13% 6% 9% 12% 6% 9% 6% 6% 7% 19%	2464
	11th to 20th	Night	10% 16% 6% 11% 8% 5% 7% 5% 4 7% 22%	2273
	21st to end	Night	9% 17% 7% 11% 8% 5% 7% 5% 5% 6% 20%	1902
March	1st to 10th	Night	11% 10% 6% 12% 10% 5% 6% 5% 5% 5% 25%	2049
	11th to 20th	Night	16% 13% 5% 9% 9% 5% 4 4 4 5% 26%	1979
	21st to end	Night	13% 12% 4 7% 6% 3 5% 5% 5% 6% 33%	2178
April	1st to 10th	Night	17% 13% 6% 9% 6% 3 5% 4 5% 5% 26%	1809
	11th to 20th	Night	17% 9% 4 7% 7% 4 5% 5% 5% 6% 30%	1597
	21st to end	Night	20% 9% 5% 7% 6% 2 4 4 4 4 35%	1620
May	1st to 10th	Night	16% 9% 3 7% 6% 4 5% 5% 5% 7% 33%	1517
	11th to 20th	Night	18% 8% 4 7% 5% 4 4 6% 6% 6% 33%	1415
	21st to end	Night	17% 7% 4 5% 5% 3 4 5% 5% 7% 38%	1366
June	1st to 10th	Night	21% 8% 3 6% 6% 4 4 4 7% 7% 32%	1260
	11th to 20th	Night	16% 5% 3 6% 6% 3 4 4 5% 8% 39%	1260
	21st to end	Night	18% 7% 4 4 5% 3 6% 4 6% 8% 35%	1260
July	1st to 10th	Night	15% 5% 3 6% 6% 3 6% 5% 6% 7% 38%	1260
	11th to 20th	Night	14% 6% 2 4 5% 4 5% 7% 5% 8% 39%	1260
	21st to end	Night	12% 8% 3 6% 6% 3 5% 6% 7% 8% 37%	1393
August	1st to 10th	Night	12% 7% 3 6% 6% 5% 5% 5% 5% 9% 36%	1605
	11th to 20th	Night	13% 6% 3 5% 6% 4 4 6% 5% 8% 40%	1598
	21st to end	Night	16% 8% 3 4 6% 3 4 5% 6% 7% 38%	1782
September	1st to 10th	Night	17% 7% 4 6% 5% 2 4 5% 5% 6% 39%	1764
	11th to 20th	Night	21% 10% 3 6% 5% 3 3 4 4 8% 34%	1934
	21st to end	Night	22% 9% 3 7% 5% 2 3 5% 4 6% 34%	1988
October	1st to 10th	Night	20% 11% 3 6% 6% 3 5% 4 5% 5% 30%	2160
	11th to 20th	Night	27% 17% 5% 8% 6% 3 4 4 3 4 18%	2160
	21st to end	Night	22% 19% 5% 8% 6% 4 3 5% 4 5% 19%	2523
November	1st to 10th	Night	18% 17% 7% 10% 8% 4 5% 4 4 4 19%	2592
	11th to 20th	Night	22% 16% 7% 13% 8% 4 4 4 3 3 15%	2660
	21st to end	Night	21% 18% 7% 14% 10% 4 5% 4 3 4 11%	2660
December	1st to 10th	Night	15% 19% 7% 14% 11% 5% 6% 5% 4 4 11%	2820
	11th to 20th	Night	15% 19% 7% 11% 11% 5% 7% 5% 5% 4 12%	3526
	21st to end	Night	20% 21% 8% 13% 10% 4 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	63% 5% 9% 17% 6%	1701
	11th to 20th	Day	63% 5% 9% 15% 7%	1582
	21st to end	Day	63% 3 9% 18% 7%	1354
March	1st to 10th	Day	62% 5% 9% 14% 10% 1	1900
	11th to 20th	Day	59% 3 8% 18% 10% 1	1980
	21st to end	Day	56% 4 7% 18% 13% 2	2178
April	1st to 10th	Day	63% 4 7% 15% 10%	2166
	11th to 20th	Day	54% 4 9% 22% 11% 1	2312
	21st to end	Day	54% 4 9% 17% 13% 3	2340
May	1st to 10th	Day	56% 4 10% 16% 13% 2	2443
	11th to 20th	Day	53% 5% 9% 22% 12% 1	2482
	21st to end	Day	50% 5% 12% 21% 11% 1	2908
June	1st to 10th	Day	53% 5% 10% 21% 10% 1	2700
	11th to 20th	Day	45% 6% 10% 24% 14% 1	2700
	21st to end	Day	50% 6% 12% 21% 10% 1	2700
July	1st to 10th	Day	46% 7% 13% 26% 7%	2626
	11th to 20th	Day	45% 7% 16% 24% 8%	2619
	21st to end	Day	50% 7% 15% 24% 4	2760
August	1st to 10th	Day	51% 7% 16% 22% 3	2316
	11th to 20th	Day	49% 7% 15% 21% 7% 1	2303
	21st to end	Day	47% 6% 17% 24% 6%	2574
September	1st to 10th	Day	49% 6% 15% 21% 9%	2177
	11th to 20th	Day	54% 5% 17% 19% 5%	2024
	21st to end	Day	56% 5% 11% 21% 6% 1	1971
October	1st to 10th	Day	57% 4 14% 19% 6%	1800
	11th to 20th	Day	72% 4 7% 14% 3	1800
	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%	2464
	11th to 20th	Night	63% 3 11% 16% 7%	2275
	21st to end	Night	64% 3 9% 15% 8% 1	1902
March	1st to 10th	Night	62% 3 7% 16% 10% 1	2059
	11th to 20th	Night	62% 4 8% 15% 10% 1	1980
	21st to end	Night	51% 5% 8% 18% 14% 3	2178
April	1st to 10th	Night	60% 4 7% 16% 12% 1	1809
	11th to 20th	Night	54% 4 7% 20% 12% 3	1597
	21st to end	Night	52% 4 7% 15% 19% 3	1620
May	1st to 10th	Night	49% 5% 9% 22% 11% 3	1517
	11th to 20th	Night	50% 6% 9% 20% 14% 2	1416
	21st to end	Night	45% 6% 14% 18% 15% 2	1367
June	1st to 10th	Night	50% 5% 9% 20% 13% 2	1260
	11th to 20th	Night	43% 6% 10% 24% 16% 2	1260
	21st to end	Night	46% 6% 12% 21% 13% 2	1260
July	1st to 10th	Night	43% 7% 13% 25% 11% 1	1225
	11th to 20th	Night	40% 7% 16% 26% 10%	1218
	21st to end	Night	45% 8% 16% 28% 3	1316
August	1st to 10th	Night	45% 7% 17% 26% 4	1595
	11th to 20th	Night	40% 8% 19% 26% 6% 1	1598
	21st to end	Night	45% 6% 16% 25% 8%	1782
September	1st to 10th	Night	45% 6% 15% 24% 9%	1764
	11th to 20th	Night	50% 6% 18% 22% 5%	1934
	21st to end	Night	51% 5% 15% 24% 5%	1988
October	1st to 10th	Night	55% 5% 14% 19% 7%	2160
	11th to 20th	Night	71% 4 8% 13% 3	2160
	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% 15% 37% 23% 8% 1	267
	11th to 20th	Day	19% 11% 38% 24% 5% 3	240
	21st to end	Day	19% 20% 41% 17% 3 1	198
March	1st to 10th	Day	16% 12% 36% 28% 8% 1	340
	11th to 20th	Day	21% 14% 27% 28% 7% 3	420
	21st to end	Day	23% 12% 31% 25% 8% 2	462
April	1st to 10th	Day	19% 11% 33% 25% 11% 1	420
	11th to 20th	Day	24% 11% 26% 26% 10% 3	412
	21st to end	Day	22% 14% 26% 21% 13% 3	420
May	1st to 10th	Day	24% 9% 28% 22% 14% 3	423
	11th to 20th	Day	21% 10% 31% 25% 8% 5%	447
	21st to end	Day	21% 10% 28% 30% 9% 2	668
June	1st to 10th	Day	25% 8% 30% 26% 10% 2	630
	11th to 20th	Day	20% 9% 29% 27% 13% 2	630
	21st to end	Day	19% 8% 23% 30% 16% 4	630
July	1st to 10th	Day	17% 8% 30% 31% 10% 4	621
	11th to 20th	Day	17% 8% 26% 31% 15% 3	618
	21st to end	Day	16% 7% 27% 29% 16% 5%	667
August	1st to 10th	Day	19% 6% 20% 32% 16% 7%	446
	11th to 20th	Day	18% 6% 19% 31% 20% 7%	439
	21st to end	Day	20% 8% 24% 26% 14% 7%	495
September	1st to 10th	Day	20% 10% 29% 20% 16% 6%	450
	11th to 20th	Day	28% 7% 24% 27% 11% 3	450
	21st to end	Day	33% 9% 22% 21% 12% 2	450
October	1st to 10th	Day	28% 10% 27% 21% 11% 3	450
	11th to 20th	Day	36% 12% 31% 16% 3 2	450
	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% 33% 11% 1	759
	11th to 20th	Night	19% 8% 30% 32% 10% 1	703
	21st to end	Night	17% 9% 35% 27% 11%	592
March	1st to 10th	Night	18% 9% 32% 31% 8% 1	720
	11th to 20th	Night	22% 9% 31% 30% 8% 1	720
	21st to end	Night	19% 8% 31% 31% 10% 1	792
April	1st to 10th	Night	24% 10% 30% 29% 7% 1	688
	11th to 20th	Night	21% 8% 29% 31% 10% 1	533
	21st to end	Night	24% 7% 27% 30% 11% 1	540
May	1st to 10th	Night	19% 4 34% 33% 11%	437
	11th to 20th	Night	24% 7% 28% 31% 9% 1	354
	21st to end	Night	19% 6% 31% 39% 5% 1	389
June	1st to 10th	Night	26% 7% 23% 32% 11%	360
	11th to 20th	Night	19% 6% 29% 37% 9%	360
	21st to end	Night	21% 3 23% 40% 13%	360
July	1st to 10th	Night	17% 4 26% 40% 11% 1	350
	11th to 20th	Night	18% 5% 22% 39% 17%	348
	21st to end	Night	16% 6% 19% 40% 18% 1	394
August	1st to 10th	Night	18% 5% 22% 36% 17% 2	531
	11th to 20th	Night	16% 4 21% 37% 20% 2	534
	21st to end	Night	20% 5% 24% 30% 18% 2	594
September	1st to 10th	Night	21% 6% 27% 29% 16% 2	684
	11th to 20th	Night	28% 7% 25% 28% 11% 2	720
	21st to end	Night	26% 6% 24% 27% 15% 2	720
October	1st to 10th	Night	27% 7% 27% 28% 10% 1	720
	11th to 20th	Night	38% 8% 28% 19% 5% 2	720
	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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