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 2024-03-18.

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	18% 11% 4 8% 7% 4 6% 5% 5% 6% 25%	78186
	Night	18% 14% 5% 9% 8% 4 5% 5% 5% 6% 22%	81607
Transparency	Day	59% 7% 11% 15% 6% 1	77883
	Night	63% 7% 10% 14% 6% 1	81444
Seeing	Day	25% 17% 29% 20% 8% 2	14480
	Night	25% 14% 28% 24% 8% 1	22968

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% 17% 10% 16% 10% 4 5% 4 5% 4 11%	2366
	11th to 20th	Day	11% 12% 8% 14% 16% 6% 9% 6% 5% 4 10%	2520
	21st to end	Day	8% 12% 6% 12% 9% 6% 6% 7% 5% 6% 23%	2772
February	1st to 10th	Day	7% 12% 6% 10% 10% 7% 9% 7% 7% 6% 19%	1520
	11th to 20th	Day	11% 14% 6% 13% 10% 6% 7% 5% 5% 6% 16%	1751
	21st to end	Day	9% 13% 6% 8% 9% 5% 9% 7% 5% 6% 22%	1570
March	1st to 10th	Day	15% 12% 5% 8% 6% 4 6% 7% 5% 7% 25%	1897
	11th to 20th	Day	16% 13% 5% 8% 9% 4 6% 5% 5% 5% 24%	1965
	21st to end	Day	17% 13% 4 9% 5% 4 5% 5% 4 6% 28%	2306
April	1st to 10th	Day	19% 12% 5% 9% 8% 3 5% 4 5% 5% 24%	2160
	11th to 20th	Day	18% 8% 3 6% 6% 4 4 5% 5% 7% 33%	2253
	21st to end	Day	19% 9% 4 6% 6% 3 5% 4 6% 7% 32%	2340
May	1st to 10th	Day	22% 9% 3 5% 4 3 4 4 5% 6% 33%	2443
	11th to 20th	Day	17% 7% 3 6% 6% 4 5% 5% 5% 6% 35%	2478
	21st to end	Day	20% 6% 3 5% 5% 4 5% 5% 6% 7% 33%	2895
June	1st to 10th	Day	20% 7% 3 6% 6% 3 5% 5% 6% 6% 31%	2700
	11th to 20th	Day	18% 6% 3 7% 6% 3 5% 5% 6% 8% 33%	2700
	21st to end	Day	21% 8% 3 6% 6% 4 5% 5% 5% 7% 29%	2700
July	1st to 10th	Day	20% 7% 3 6% 6% 4 6% 5% 6% 8% 28%	2700
	11th to 20th	Day	16% 7% 3 8% 8% 4 6% 7% 7% 8% 28%	2548
	21st to end	Day	16% 7% 3 7% 7% 4 6% 6% 7% 7% 29%	2744
August	1st to 10th	Day	18% 9% 3 7% 8% 4 7% 6% 7% 8% 23%	2506
	11th to 20th	Day	17% 7% 3 7% 6% 4 5% 6% 6% 8% 30%	2328
	21st to end	Day	20% 7% 3 8% 6% 4 4 4 5% 8% 30%	2514
September	1st to 10th	Day	21% 7% 3 6% 6% 4 5% 6% 5% 8% 30%	2160
	11th to 20th	Day	21% 6% 3 5% 5% 3 6% 4 6% 6% 35%	2003
	21st to end	Day	23% 8% 3 6% 6% 3 3 4 5% 6% 32%	1980
October	1st to 10th	Day	21% 7% 3 7% 7% 4 4 5% 5% 6% 30%	1967
	11th to 20th	Day	27% 14% 3 8% 7% 4 6% 4 5% 5% 16%	1622
	21st to end	Day	27% 16% 5% 7% 5% 3 4 4 5% 4 21%	1782
November	1st to 10th	Day	21% 13% 5% 10% 7% 4 5% 5% 4 6% 21%	1671
	11th to 20th	Day	22% 17% 6% 11% 7% 3 5% 4 5% 5% 16%	1566
	21st to end	Day	19% 22% 5% 11% 8% 4 5% 4 4 5% 12%	1330
December	1st to 10th	Day	20% 18% 7% 12% 10% 3 6% 6% 4 4 10%	1330
	11th to 20th	Day	18% 17% 5% 12% 10% 4 6% 5% 4 5% 15%	1668
	21st to end	Day	18% 18% 6% 10% 11% 5% 7% 4 4 4 13%	2431
January	1st to 10th	Night	12% 20% 8% 12% 12% 6% 6% 5% 4 4 11%	4580
	11th to 20th	Night	12% 16% 6% 15% 13% 5% 6% 5% 4 5% 12%	4440
	21st to end	Night	8% 15% 8% 11% 9% 5% 6% 6% 6% 6% 20%	4884
February	1st to 10th	Night	9% 12% 7% 11% 10% 6% 7% 6% 6% 6% 21%	2660
	11th to 20th	Night	11% 17% 8% 13% 9% 5% 6% 4 5% 4 17%	2313
	21st to end	Night	11% 15% 6% 11% 9% 4 5% 4 5% 6% 24%	1884
March	1st to 10th	Night	15% 14% 6% 10% 7% 4 6% 4 4 5% 24%	2270
	11th to 20th	Night	16% 14% 6% 10% 7% 4 5% 5% 5% 6% 22%	2159
	21st to end	Night	15% 15% 5% 8% 5% 3 5% 4 3 5% 30%	2048
April	1st to 10th	Night	22% 15% 5% 8% 7% 3 6% 4 3 5% 24%	1800
	11th to 20th	Night	22% 11% 3 6% 5% 3 4 4 5% 6% 32%	1656
	21st to end	Night	20% 10% 3 6% 4 3 5% 4 4 6% 34%	1620
May	1st to 10th	Night	24% 10% 4 7% 5% 3 4 4 4 5% 31%	1532
	11th to 20th	Night	18% 9% 3 7% 6% 3 3 5% 5% 6% 35%	1415
	21st to end	Night	23% 8% 3 7% 5% 2 4 4 5% 7% 30%	1377
June	1st to 10th	Night	19% 8% 5% 6% 6% 3 5% 6% 6% 8% 29%	1260
	11th to 20th	Night	17% 8% 4 6% 5% 3 5% 5% 4 8% 35%	1260
	21st to end	Night	21% 7% 3 7% 6% 5% 5% 6% 5% 8% 28%	1260
July	1st to 10th	Night	19% 7% 3 6% 5% 4 6% 6% 6% 7% 29%	1260
	11th to 20th	Night	15% 6% 3 7% 7% 5% 6% 6% 8% 9% 27%	1409
	21st to end	Night	18% 8% 4 7% 7% 5% 5% 5% 6% 8% 28%	1574
August	1st to 10th	Night	18% 7% 4 6% 7% 4 6% 6% 6% 9% 27%	1432
	11th to 20th	Night	20% 7% 3 7% 7% 3 5% 6% 6% 6% 29%	1554
	21st to end	Night	21% 6% 2 7% 6% 4 6% 6% 5% 7% 30%	1840
September	1st to 10th	Night	21% 7% 3 6% 6% 3 4 5% 5% 6% 34%	1800
	11th to 20th	Night	20% 7% 4 7% 6% 4 5% 4 6% 5% 33%	1957
	21st to end	Night	22% 7% 2 7% 7% 4 5% 4 4 5% 33%	1980
October	1st to 10th	Night	22% 8% 3 6% 6% 3 4 5% 4 6% 33%	1989
	11th to 20th	Night	31% 13% 3 7% 7% 3 4 5% 5% 5% 19%	2337
	21st to end	Night	28% 14% 3 7% 6% 3 4 4 5% 6% 20%	2574
November	1st to 10th	Night	24% 16% 5% 8% 6% 3 4 4 4 5% 20%	2407
	11th to 20th	Night	21% 17% 6% 10% 6% 3 5% 4 5% 5% 19%	2609
	21st to end	Night	20% 20% 6% 13% 8% 3 4 4 4 4 13%	2850
December	1st to 10th	Night	21% 19% 7% 13% 8% 4 6% 6% 3 4 10%	2850
	11th to 20th	Night	20% 18% 6% 11% 10% 4 5% 5% 4 5% 13%	3531
	21st to end	Night	17% 23% 7% 10% 9% 4 5% 4 3 4 15%	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	72% 10% 9% 8% 1	2367
	11th to 20th	Day	78% 6% 7% 7% 3	2520
	21st to end	Day	64% 7% 6% 15% 8%	2772
February	1st to 10th	Day	63% 9% 8% 12% 6% 1	1520
	11th to 20th	Day	69% 6% 9% 10% 5%	1759
	21st to end	Day	61% 7% 10% 15% 6% 1	1570
March	1st to 10th	Day	59% 7% 11% 14% 8% 1	1900
	11th to 20th	Day	63% 4 10% 15% 8%	1965
	21st to end	Day	58% 6% 10% 18% 7% 1	2306
April	1st to 10th	Day	64% 5% 11% 11% 7% 2	2160
	11th to 20th	Day	53% 5% 12% 20% 9% 1	2253
	21st to end	Day	53% 7% 11% 17% 11% 1	2340
May	1st to 10th	Day	52% 6% 12% 16% 12% 2	2443
	11th to 20th	Day	49% 7% 9% 22% 12% 1	2482
	21st to end	Day	50% 8% 9% 20% 12% 1	2895
June	1st to 10th	Day	53% 6% 11% 17% 12% 1	2700
	11th to 20th	Day	49% 7% 12% 19% 11% 1	2700
	21st to end	Day	53% 9% 12% 17% 8% 1	2700
July	1st to 10th	Day	51% 8% 16% 20% 5%	2625
	11th to 20th	Day	52% 9% 15% 18% 6%	2471
	21st to end	Day	53% 10% 15% 18% 4	2591
August	1st to 10th	Day	56% 11% 16% 14% 2	2492
	11th to 20th	Day	51% 8% 19% 17% 5%	2328
	21st to end	Day	52% 9% 15% 20% 5%	2514
September	1st to 10th	Day	52% 7% 14% 20% 7%	2160
	11th to 20th	Day	49% 7% 17% 20% 6%	2003
	21st to end	Day	53% 8% 14% 19% 6%	1980
October	1st to 10th	Day	55% 7% 13% 17% 7% 1	1967
	11th to 20th	Day	71% 7% 10% 11% 1	1622
	21st to end	Day	68% 7% 10% 11% 3 1	1782
November	1st to 10th	Day	67% 7% 10% 13% 3	1671
	11th to 20th	Day	71% 7% 10% 9% 2	1566
	21st to end	Day	75% 9% 10% 5% 1	1330
December	1st to 10th	Day	79% 6% 7% 8% 1	1330
	11th to 20th	Day	71% 7% 9% 10% 4	1668
	21st to end	Day	71% 10% 6% 8% 5%	2431
January	1st to 10th	Night	76% 8% 7% 7% 1	4580
	11th to 20th	Night	73% 6% 9% 8% 3	4440
	21st to end	Night	64% 7% 8% 15% 6%	4884
February	1st to 10th	Night	61% 8% 9% 15% 6%	2660
	11th to 20th	Night	70% 6% 8% 11% 5%	2315
	21st to end	Night	63% 4 10% 17% 6%	1884
March	1st to 10th	Night	63% 5% 9% 16% 7% 1	2280
	11th to 20th	Night	63% 6% 7% 15% 7% 1	2160
	21st to end	Night	58% 6% 8% 18% 9% 2	2048
April	1st to 10th	Night	65% 5% 8% 13% 8% 2	1800
	11th to 20th	Night	54% 5% 9% 19% 12% 1	1656
	21st to end	Night	51% 6% 8% 22% 11% 2	1620
May	1st to 10th	Night	57% 5% 9% 14% 13% 2	1532
	11th to 20th	Night	50% 7% 9% 20% 13% 1	1416
	21st to end	Night	54% 6% 9% 18% 12% 1	1378
June	1st to 10th	Night	52% 10% 10% 18% 8% 2	1260
	11th to 20th	Night	47% 6% 12% 19% 12% 3	1260
	21st to end	Night	54% 10% 10% 17% 9%	1260
July	1st to 10th	Night	52% 8% 15% 21% 5%	1225
	11th to 20th	Night	48% 11% 15% 19% 6% 1	1363
	21st to end	Night	55% 11% 10% 19% 5%	1486
August	1st to 10th	Night	51% 10% 17% 19% 2	1422
	11th to 20th	Night	53% 10% 15% 17% 5%	1554
	21st to end	Night	51% 9% 14% 22% 4	1840
September	1st to 10th	Night	48% 9% 13% 21% 9%	1800
	11th to 20th	Night	52% 7% 16% 18% 6%	1957
	21st to end	Night	52% 8% 11% 22% 8%	1980
October	1st to 10th	Night	52% 7% 13% 20% 8% 1	1989
	11th to 20th	Night	68% 7% 10% 12% 3	2337
	21st to end	Night	66% 7% 9% 12% 4 1	2574
November	1st to 10th	Night	66% 6% 12% 11% 4	2407
	11th to 20th	Night	69% 7% 11% 10% 3	2609
	21st to end	Night	76% 7% 10% 6% 2	2850
December	1st to 10th	Night	77% 6% 9% 6% 1	2850
	11th to 20th	Night	74% 7% 6% 10% 3	3532
	21st to end	Night	73% 7% 7% 10% 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	22% 19% 38% 16% 4	180
	11th to 20th	Day	22% 18% 31% 23% 6% 1	180
	21st to end	Day	18% 17% 33% 25% 5% 3	198
February	1st to 10th	Day	17% 21% 46% 12% 4 1	180
	11th to 20th	Day	21% 22% 34% 17% 5% 1	392
	21st to end	Day	23% 24% 30% 18% 6%	382
March	1st to 10th	Day	26% 15% 33% 19% 6%	460
	11th to 20th	Day	27% 20% 28% 17% 7% 1	449
	21st to end	Day	27% 18% 29% 19% 6%	462
April	1st to 10th	Day	28% 21% 28% 18% 5% 1	420
	11th to 20th	Day	27% 17% 29% 19% 8%	412
	21st to end	Day	26% 20% 32% 15% 6% 1	420
May	1st to 10th	Day	29% 18% 29% 17% 7%	423
	11th to 20th	Day	20% 18% 31% 22% 8% 1	447
	21st to end	Day	26% 17% 31% 18% 7% 1	655
June	1st to 10th	Day	25% 16% 30% 21% 7% 1	630
	11th to 20th	Day	21% 14% 29% 22% 13% 2	630
	21st to end	Day	24% 12% 29% 23% 11% 1	630
July	1st to 10th	Day	23% 11% 29% 25% 11% 1	620
	11th to 20th	Day	19% 13% 29% 27% 11% 2	470
	21st to end	Day	18% 13% 31% 24% 12% 3	488
August	1st to 10th	Day	21% 11% 26% 27% 11% 4	446
	11th to 20th	Day	18% 11% 26% 26% 16% 3	439
	21st to end	Day	22% 17% 25% 18% 12% 5%	495
September	1st to 10th	Day	23% 16% 27% 19% 10% 5%	450
	11th to 20th	Day	24% 15% 28% 20% 10% 3	450
	21st to end	Day	27% 16% 23% 20% 10% 4	450
October	1st to 10th	Day	22% 17% 27% 20% 10% 3	450
	11th to 20th	Day	37% 18% 22% 13% 7% 3	360
	21st to end	Day	37% 18% 24% 15% 5% 1	396
November	1st to 10th	Day	35% 20% 25% 15% 4 1	365
	11th to 20th	Day	30% 18% 25% 19% 7% 1	313
	21st to end	Day	34% 22% 30% 11% 3	180
December	1st to 10th	Day	28% 14% 33% 17% 8% 1	180
	11th to 20th	Day	27% 26% 31% 9% 6% 2	180
	21st to end	Day	25% 31% 22% 16% 6% 1	198
January	1st to 10th	Night	25% 16% 32% 22% 5%	801
	11th to 20th	Night	25% 16% 27% 25% 7% 1	760
	21st to end	Night	17% 13% 32% 29% 8% 1	836
February	1st to 10th	Night	15% 15% 37% 25% 7% 1	760
	11th to 20th	Night	23% 18% 32% 21% 6% 1	743
	21st to end	Night	21% 17% 32% 22% 8% 1	628
March	1st to 10th	Night	23% 15% 34% 23% 5%	760
	11th to 20th	Night	25% 16% 30% 19% 10%	752
	21st to end	Night	23% 18% 29% 24% 6% 1	792
April	1st to 10th	Night	29% 15% 29% 20% 6% 1	720
	11th to 20th	Night	28% 13% 28% 24% 6%	592
	21st to end	Night	26% 13% 31% 23% 6%	540
May	1st to 10th	Night	32% 13% 25% 23% 7%	452
	11th to 20th	Night	22% 10% 33% 27% 8% 1	354
	21st to end	Night	28% 12% 28% 25% 6%	389
June	1st to 10th	Night	20% 7% 37% 30% 5% 1	360
	11th to 20th	Night	18% 11% 26% 34% 11% 1	360
	21st to end	Night	23% 8% 28% 31% 8% 1	360
July	1st to 10th	Night	22% 10% 29% 29% 9% 1	350
	11th to 20th	Night	15% 8% 26% 37% 14% 1	348
	21st to end	Night	20% 7% 25% 35% 11% 1	394
August	1st to 10th	Night	18% 8% 23% 35% 15% 1	358
	11th to 20th	Night	20% 8% 23% 31% 17% 1	490
	21st to end	Night	23% 8% 25% 29% 13% 2	652
September	1st to 10th	Night	24% 11% 23% 29% 11% 1	720
	11th to 20th	Night	25% 9% 28% 26% 11% 1	720
	21st to end	Night	25% 11% 27% 25% 10% 2	720
October	1st to 10th	Night	24% 13% 25% 26% 11% 1	720
	11th to 20th	Night	36% 15% 22% 18% 8% 1	720
	21st to end	Night	35% 16% 23% 18% 7% 1	792
November	1st to 10th	Night	34% 17% 23% 18% 6% 1	740
	11th to 20th	Night	28% 21% 25% 20% 6% 1	800
	21st to end	Night	29% 19% 27% 19% 5% 1	850
December	1st to 10th	Night	31% 14% 26% 21% 7% 1	850
	11th to 20th	Night	28% 18% 25% 21% 7% 1	850
	21st to end	Night	26% 19% 25% 21% 7% 1	935

Page generated at 2024-03-15 14:01:41. Version ac07

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