Chicoutimi
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chicoutimi clear sky chart from 2005-11-06 to 2025-06-10.

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% 11% 4 10% 6% 5% 5% 4 5% 6% 25%	119442
	Night	17% 14% 5% 11% 7% 5% 5% 4 5% 6% 21%	118875
Transparency	Day	58% 7% 12% 16% 6% 1	122909
	Night	63% 7% 10% 15% 5%	123569
Seeing	Day	25% 17% 29% 20% 8% 2	16133
	Night	25% 14% 28% 24% 8% 1	24485

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% 10% 20% 7% 6% 5% 3 4 3 8%	3394
	11th to 20th	Day	8% 15% 8% 19% 13% 6% 8% 4 5% 4 9%	3570
	21st to end	Day	5% 9% 6% 14% 8% 8% 8% 6% 6% 7% 24%	3960
February	1st to 10th	Day	7% 14% 5% 12% 9% 10% 7% 5% 7% 6% 18%	1600
	11th to 20th	Day	11% 16% 6% 14% 9% 8% 5% 4 5% 5% 16%	1847
	21st to end	Day	8% 14% 5% 10% 8% 8% 9% 5% 6% 6% 22%	1650
March	1st to 10th	Day	14% 16% 5% 10% 4 4 5% 5% 5% 6% 27%	4476
	11th to 20th	Day	14% 17% 6% 12% 7% 5% 5% 4 5% 6% 20%	4764
	21st to end	Day	12% 15% 5% 11% 6% 6% 5% 4 5% 6% 25%	5802
April	1st to 10th	Day	18% 14% 4 11% 6% 5% 4 3 5% 5% 26%	2400
	11th to 20th	Day	18% 9% 4 7% 6% 5% 5% 4 5% 7% 32%	2507
	21st to end	Day	19% 10% 3 7% 5% 4 4 3 6% 6% 31%	2600
May	1st to 10th	Day	22% 11% 3 7% 4 4 4 3 5% 6% 30%	6157
	11th to 20th	Day	23% 8% 3 7% 5% 5% 5% 4 5% 6% 30%	6318
	21st to end	Day	18% 8% 3 7% 5% 5% 5% 4 6% 8% 31%	7399
June	1st to 10th	Day	20% 8% 3 7% 6% 4 5% 4 6% 7% 31%	2985
	11th to 20th	Day	17% 7% 3 7% 6% 5% 5% 5% 6% 7% 32%	2850
	21st to end	Day	21% 9% 3 7% 6% 5% 5% 4 5% 7% 28%	2850
July	1st to 10th	Day	17% 9% 3 8% 5% 5% 6% 4 6% 8% 28%	4760
	11th to 20th	Day	15% 8% 4 9% 6% 5% 6% 5% 7% 8% 27%	4482
	21st to end	Day	13% 7% 2 8% 6% 5% 6% 5% 7% 8% 34%	4814
August	1st to 10th	Day	15% 7% 3 8% 6% 6% 6% 5% 8% 10% 26%	4423
	11th to 20th	Day	18% 6% 2 8% 6% 6% 6% 5% 7% 8% 27%	4082
	21st to end	Day	19% 7% 3 10% 5% 5% 4 3 5% 7% 32%	4416
September	1st to 10th	Day	20% 8% 3 7% 5% 6% 5% 4 5% 8% 30%	2280
	11th to 20th	Day	20% 6% 3 6% 4 4 6% 3 6% 6% 36%	2114
	21st to end	Day	22% 8% 3 7% 5% 4 4 3 5% 6% 32%	2090
October	1st to 10th	Day	21% 8% 3 8% 6% 5% 5% 4 5% 6% 30%	2076
	11th to 20th	Day	27% 14% 4 8% 7% 5% 6% 3 5% 5% 16%	1712
	21st to end	Day	26% 16% 5% 8% 4 4 4 3 5% 4 21%	1881
November	1st to 10th	Day	20% 14% 5% 10% 7% 5% 4 4 4 5% 20%	1761
	11th to 20th	Day	21% 17% 6% 12% 6% 4 4 3 4 5% 17%	1648
	21st to end	Day	18% 24% 5% 13% 8% 5% 5% 3 4 4 12%	1400
December	1st to 10th	Day	14% 19% 8% 15% 11% 6% 5% 4 4 4 11%	2280
	11th to 20th	Day	17% 15% 7% 14% 10% 6% 6% 5% 4 6% 11%	2618
	21st to end	Day	16% 17% 6% 12% 8% 7% 7% 4 6% 5% 12%	3476
January	1st to 10th	Night	13% 26% 10% 14% 8% 6% 4 3 3 3 8%	6556
	11th to 20th	Night	9% 19% 9% 21% 10% 6% 5% 4 4 4 9%	6315
	21st to end	Night	5% 11% 6% 12% 9% 8% 8% 6% 8% 7% 20%	6996
February	1st to 10th	Night	8% 13% 5% 13% 9% 7% 7% 5% 6% 6% 21%	2800
	11th to 20th	Night	10% 20% 7% 14% 8% 7% 5% 3 5% 4 17%	2437
	21st to end	Night	11% 17% 5% 13% 8% 5% 5% 3 5% 6% 23%	1980
March	1st to 10th	Night	19% 16% 6% 11% 6% 4 6% 4 5% 5% 18%	5364
	11th to 20th	Night	14% 16% 5% 11% 6% 7% 6% 4 6% 6% 18%	5194
	21st to end	Night	14% 17% 5% 11% 4 4 4 3 4 6% 28%	5128
April	1st to 10th	Night	21% 15% 5% 9% 6% 4 4 3 3 5% 26%	2000
	11th to 20th	Night	21% 13% 4 7% 5% 4 3 4 4 5% 31%	1842
	21st to end	Night	21% 12% 2 7% 4 5% 4 4 4 6% 33%	1800
May	1st to 10th	Night	23% 9% 3 7% 4 4 4 3 5% 5% 33%	3826
	11th to 20th	Night	23% 11% 3 8% 4 4 4 3 5% 5% 29%	3575
	21st to end	Night	20% 9% 3 7% 5% 4 4 4 5% 8% 32%	3493
June	1st to 10th	Night	19% 8% 5% 7% 5% 5% 5% 4 6% 7% 30%	1399
	11th to 20th	Night	17% 9% 3 7% 4 4 4 4 5% 8% 35%	1330
	21st to end	Night	21% 8% 3 8% 6% 6% 4 4 5% 7% 28%	1330
July	1st to 10th	Night	18% 7% 4 9% 5% 5% 6% 4 6% 7% 29%	2210
	11th to 20th	Night	15% 7% 3 8% 6% 6% 6% 5% 8% 9% 27%	2476
	21st to end	Night	14% 7% 3 7% 5% 6% 5% 5% 6% 8% 35%	2739
August	1st to 10th	Night	17% 7% 4 8% 6% 6% 7% 5% 6% 9% 26%	2506
	11th to 20th	Night	19% 7% 3 8% 6% 5% 6% 5% 7% 7% 26%	2714
	21st to end	Night	17% 7% 3 9% 5% 6% 6% 4 6% 7% 31%	3238
September	1st to 10th	Night	20% 7% 3 7% 5% 4 4 4 5% 6% 34%	1900
	11th to 20th	Night	19% 7% 3 8% 5% 5% 5% 3 6% 5% 33%	2066
	21st to end	Night	21% 8% 2 8% 6% 5% 4 4 4 5% 33%	2090
October	1st to 10th	Night	22% 8% 3 7% 4 5% 4 4 5% 6% 32%	2100
	11th to 20th	Night	31% 13% 3 8% 5% 4 4 3 5% 4 20%	2467
	21st to end	Night	27% 15% 3 8% 5% 4 4 4 5% 6% 19%	2717
November	1st to 10th	Night	25% 17% 4 8% 5% 4 4 3 5% 5% 20%	2537
	11th to 20th	Night	20% 18% 5% 11% 4 4 5% 3 5% 5% 19%	2747
	21st to end	Night	20% 22% 6% 13% 7% 4 4 3 4 4 13%	3000
December	1st to 10th	Night	14% 17% 8% 20% 11% 6% 5% 3 4 3 8%	4910
	11th to 20th	Night	19% 18% 6% 15% 8% 5% 5% 4 4 5% 11%	5591
	21st to end	Night	15% 20% 6% 12% 7% 6% 6% 2 4 7% 14%	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	80% 7% 6% 5% 1	3395
	11th to 20th	Day	77% 6% 8% 7% 3	3600
	21st to end	Day	60% 6% 8% 17% 9%	3960
February	1st to 10th	Day	63% 9% 8% 12% 6% 1	1600
	11th to 20th	Day	69% 6% 9% 10% 5%	1855
	21st to end	Day	60% 7% 10% 16% 6% 1	1650
March	1st to 10th	Day	57% 7% 11% 14% 10% 1	4479
	11th to 20th	Day	65% 6% 11% 10% 7%	4764
	21st to end	Day	59% 5% 9% 18% 8% 2	5802
April	1st to 10th	Day	62% 5% 10% 13% 7% 2	2400
	11th to 20th	Day	53% 5% 12% 20% 9% 1	2507
	21st to end	Day	54% 7% 10% 17% 10% 1	2600
May	1st to 10th	Day	53% 7% 11% 17% 11% 1	6168
	11th to 20th	Day	54% 9% 9% 19% 9% 1	6322
	21st to end	Day	50% 7% 11% 19% 11% 1	7399
June	1st to 10th	Day	52% 7% 10% 18% 12% 1	2985
	11th to 20th	Day	49% 8% 13% 19% 11% 1	2850
	21st to end	Day	54% 9% 12% 18% 8% 1	2850
July	1st to 10th	Day	51% 7% 15% 24% 3	4685
	11th to 20th	Day	52% 9% 18% 17% 4	4405
	21st to end	Day	47% 9% 18% 20% 6%	4661
August	1st to 10th	Day	50% 10% 18% 20% 3	4409
	11th to 20th	Day	52% 8% 22% 14% 3	4122
	21st to end	Day	51% 7% 15% 18% 8%	4416
September	1st to 10th	Day	52% 7% 14% 21% 6%	2280
	11th to 20th	Day	47% 7% 18% 21% 6%	2114
	21st to end	Day	53% 7% 14% 20% 6%	2090
October	1st to 10th	Day	56% 8% 12% 20% 4	3453
	11th to 20th	Day	67% 7% 13% 12% 1	2824
	21st to end	Day	61% 8% 16% 13% 2	3081
November	1st to 10th	Day	67% 7% 11% 12% 3	1761
	11th to 20th	Day	71% 7% 9% 10% 3	1648
	21st to end	Day	75% 9% 10% 5% 1	1400
December	1st to 10th	Day	78% 5% 11% 6%	2280
	11th to 20th	Day	73% 6% 11% 7% 2	2618
	21st to end	Day	69% 10% 6% 10% 4	3476
January	1st to 10th	Night	82% 6% 6% 5% 1	6556
	11th to 20th	Night	78% 5% 8% 7% 3	6360
	21st to end	Night	60% 7% 9% 18% 6%	6996
February	1st to 10th	Night	61% 7% 9% 16% 7%	2800
	11th to 20th	Night	69% 6% 8% 11% 5%	2439
	21st to end	Night	63% 4 10% 17% 6%	1980
March	1st to 10th	Night	67% 6% 8% 13% 6%	5374
	11th to 20th	Night	63% 9% 10% 12% 6%	5195
	21st to end	Night	58% 5% 7% 19% 10% 1	5128
April	1st to 10th	Night	62% 5% 8% 15% 9% 2	2000
	11th to 20th	Night	55% 5% 8% 19% 12% 1	1842
	21st to end	Night	53% 6% 8% 21% 10% 2	1800
May	1st to 10th	Night	52% 7% 8% 19% 13% 1	3832
	11th to 20th	Night	53% 7% 9% 22% 9% 1	3576
	21st to end	Night	50% 7% 11% 17% 13% 1	3494
June	1st to 10th	Night	52% 9% 10% 19% 9% 2	1399
	11th to 20th	Night	47% 7% 13% 19% 12% 3	1330
	21st to end	Night	54% 9% 10% 17% 9%	1330
July	1st to 10th	Night	53% 7% 13% 23% 5%	2175
	11th to 20th	Night	48% 10% 20% 19% 4	2430
	21st to end	Night	45% 9% 18% 20% 8%	2651
August	1st to 10th	Night	50% 10% 18% 18% 4	2496
	11th to 20th	Night	53% 12% 19% 14% 3	2740
	21st to end	Night	49% 9% 12% 25% 5%	3238
September	1st to 10th	Night	48% 9% 14% 21% 9%	1900
	11th to 20th	Night	51% 7% 15% 20% 6%	2066
	21st to end	Night	52% 8% 11% 22% 7%	2090
October	1st to 10th	Night	54% 7% 13% 20% 5% 1	3503
	11th to 20th	Night	64% 8% 10% 15% 3	4094
	21st to end	Night	64% 8% 14% 10% 3	4467
November	1st to 10th	Night	66% 7% 12% 11% 4	2537
	11th to 20th	Night	69% 7% 11% 11% 3	2747
	21st to end	Night	77% 6% 9% 6% 2	3000
December	1st to 10th	Night	78% 6% 9% 5% 1	4910
	11th to 20th	Night	75% 6% 6% 11% 2	5592
	21st to end	Night	70% 6% 7% 13% 3	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% 20% 36% 17% 4	200
	11th to 20th	Day	22% 18% 31% 24% 6% 1	200
	21st to end	Day	16% 18% 33% 25% 5% 3	220
February	1st to 10th	Day	16% 20% 48% 12% 4 1	200
	11th to 20th	Day	22% 22% 34% 17% 4	428
	21st to end	Day	21% 23% 31% 18% 6%	414
March	1st to 10th	Day	27% 15% 32% 19% 7%	500
	11th to 20th	Day	27% 20% 29% 16% 7% 1	500
	21st to end	Day	28% 20% 29% 18% 6%	550
April	1st to 10th	Day	30% 19% 28% 18% 4 1	500
	11th to 20th	Day	27% 18% 27% 20% 7% 1	492
	21st to end	Day	26% 20% 31% 16% 6% 1	500
May	1st to 10th	Day	30% 18% 28% 17% 7% 1	503
	11th to 20th	Day	21% 18% 29% 23% 8% 1	527
	21st to end	Day	26% 17% 30% 18% 8% 1	763
June	1st to 10th	Day	24% 15% 30% 23% 7% 1	725
	11th to 20th	Day	21% 14% 29% 22% 12% 2	680
	21st to end	Day	24% 12% 29% 23% 11% 1	680
July	1st to 10th	Day	22% 11% 29% 27% 11% 1	670
	11th to 20th	Day	18% 14% 29% 28% 10% 2	511
	21st to end	Day	18% 12% 30% 25% 13% 2	532
August	1st to 10th	Day	20% 12% 27% 26% 11% 3	486
	11th to 20th	Day	18% 11% 25% 26% 17% 4	479
	21st to end	Day	22% 16% 24% 19% 13% 6%	539
September	1st to 10th	Day	22% 16% 28% 20% 9% 5%	490
	11th to 20th	Day	22% 13% 27% 22% 11% 4	490
	21st to end	Day	27% 15% 23% 21% 10% 4	490
October	1st to 10th	Day	22% 17% 27% 20% 11% 3	490
	11th to 20th	Day	36% 19% 22% 13% 8% 3	390
	21st to end	Day	35% 19% 25% 16% 5% 1	429
November	1st to 10th	Day	35% 21% 24% 15% 4 1	395
	11th to 20th	Day	30% 18% 24% 20% 6% 1	340
	21st to end	Day	35% 22% 29% 12% 4	200
December	1st to 10th	Day	26% 16% 33% 18% 7% 1	200
	11th to 20th	Day	27% 24% 32% 10% 7% 2	200
	21st to end	Day	24% 29% 22% 18% 7% 1	220
January	1st to 10th	Night	25% 16% 32% 22% 5%	845
	11th to 20th	Night	24% 15% 26% 25% 9% 1	800
	21st to end	Night	16% 13% 32% 30% 8% 1	880
February	1st to 10th	Night	15% 16% 38% 25% 7% 1	800
	11th to 20th	Night	23% 18% 32% 21% 5% 1	783
	21st to end	Night	21% 16% 30% 23% 8% 1	660
March	1st to 10th	Night	23% 15% 33% 23% 5%	800
	11th to 20th	Night	25% 16% 31% 18% 10%	800
	21st to end	Night	23% 19% 29% 24% 5% 1	880
April	1st to 10th	Night	28% 16% 30% 20% 5% 1	800
	11th to 20th	Night	28% 14% 29% 23% 6%	658
	21st to end	Night	28% 14% 31% 22% 5%	600
May	1st to 10th	Night	30% 14% 28% 21% 7%	502
	11th to 20th	Night	22% 10% 32% 27% 8% 1	394
	21st to end	Night	27% 12% 28% 26% 7%	433
June	1st to 10th	Night	20% 7% 36% 31% 6% 1	400
	11th to 20th	Night	17% 11% 26% 33% 12% 1	380
	21st to end	Night	23% 8% 29% 31% 8% 1	380
July	1st to 10th	Night	22% 10% 28% 31% 9% 1	370
	11th to 20th	Night	15% 8% 26% 39% 13% 1	368
	21st to end	Night	19% 7% 25% 36% 11% 1	416
August	1st to 10th	Night	18% 8% 23% 36% 15% 1	378
	11th to 20th	Night	19% 8% 22% 31% 18% 1	518
	21st to end	Night	23% 8% 24% 30% 14% 2	689
September	1st to 10th	Night	24% 12% 24% 29% 11% 1	760
	11th to 20th	Night	24% 9% 27% 27% 12% 1	760
	21st to end	Night	25% 11% 27% 25% 10% 2	760
October	1st to 10th	Night	25% 13% 25% 26% 11% 1	760
	11th to 20th	Night	36% 14% 22% 19% 8% 1	760
	21st to end	Night	34% 16% 24% 19% 6% 1	836
November	1st to 10th	Night	35% 17% 23% 19% 6% 1	780
	11th to 20th	Night	28% 20% 24% 21% 6% 1	845
	21st to end	Night	30% 19% 26% 18% 5% 1	900
December	1st to 10th	Night	30% 13% 26% 22% 7% 1	900
	11th to 20th	Night	27% 19% 25% 21% 7% 1	900
	21st to end	Night	26% 19% 25% 22% 7% 1	990

Page generated at 2025-06-07 10:28:13. Version ac07

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