Shawinigan
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Shawinigan clear sky chart from 2005-11-06 to 2024-12-06.

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% 10% 3 8% 5% 5% 5% 4 5% 7% 32%	101597
	Night	18% 11% 3 8% 5% 4 4 3 5% 6% 33%	98101
Transparency	Day	52% 4 13% 21% 9% 1	105047
	Night	54% 3 12% 21% 9% 1	102741
Seeing	Day	24% 11% 31% 22% 9% 2	14613
	Night	24% 8% 29% 29% 9% 1	23623

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	16% 14% 5% 10% 5% 5% 5% 4 4 5% 27%	2517
	11th to 20th	Day	13% 13% 6% 13% 7% 4 5% 3 4 5% 27%	2520
	21st to end	Day	13% 12% 5% 11% 6% 5% 5% 4 6% 6% 26%	2772
February	1st to 10th	Day	13% 17% 5% 11% 7% 5% 4 3 3 5% 27%	1586
	11th to 20th	Day	13% 15% 5% 11% 6% 4 4 3 5% 5% 28%	1782
	21st to end	Day	15% 15% 5% 10% 7% 5% 4 3 4 5% 28%	1570
March	1st to 10th	Day	21% 12% 4 9% 5% 5% 4 3 4 5% 28%	3116
	11th to 20th	Day	14% 17% 4 10% 5% 4 4 3 4 5% 28%	3245
	21st to end	Day	13% 12% 3 8% 5% 4 4 3 4 5% 37%	4166
April	1st to 10th	Day	22% 13% 3 7% 4 4 3 3 4 5% 30%	2280
	11th to 20th	Day	21% 7% 2 7% 4 4 4 3 4 6% 36%	2282
	21st to end	Day	23% 11% 3 7% 4 5% 4 4 5% 6% 30%	2470
May	1st to 10th	Day	22% 8% 2 7% 4 4 4 3 5% 6% 35%	4329
	11th to 20th	Day	17% 6% 3 7% 5% 5% 5% 3 6% 9% 35%	4398
	21st to end	Day	18% 7% 2 7% 5% 5% 5% 5% 6% 7% 33%	4837
June	1st to 10th	Day	21% 8% 3 8% 5% 6% 5% 4 6% 7% 28%	2660
	11th to 20th	Day	17% 7% 3 7% 5% 5% 4 4 7% 8% 34%	2660
	21st to end	Day	22% 9% 3 8% 5% 5% 5% 4 5% 6% 27%	2660
July	1st to 10th	Day	14% 6% 3 8% 5% 5% 6% 5% 7% 8% 32%	4440
	11th to 20th	Day	16% 6% 3 7% 5% 6% 6% 5% 7% 8% 31%	4440
	21st to end	Day	14% 5% 2 6% 5% 5% 5% 4 6% 7% 41%	4814
August	1st to 10th	Day	15% 5% 2 7% 6% 6% 7% 5% 8% 9% 30%	4423
	11th to 20th	Day	19% 7% 2 6% 5% 4 5% 5% 7% 9% 32%	4118
	21st to end	Day	18% 6% 2 6% 4 4 5% 3 6% 7% 38%	4181
September	1st to 10th	Day	15% 5% 3 5% 5% 4 4 4 6% 8% 42%	2280
	11th to 20th	Day	15% 6% 2 5% 3 3 4 3 5% 8% 45%	2166
	21st to end	Day	21% 7% 3 6% 3 3 3 3 5% 6% 40%	2090
October	1st to 10th	Day	21% 7% 3 7% 5% 4 4 3 4 7% 34%	2009
	11th to 20th	Day	22% 9% 2 9% 6% 5% 4 4 5% 6% 27%	1800
	21st to end	Day	25% 11% 4 7% 3 4 4 3 4 6% 28%	1881
November	1st to 10th	Day	17% 12% 3 6% 5% 5% 5% 4 5% 6% 33%	1761
	11th to 20th	Day	20% 12% 4 8% 6% 4 4 3 4 5% 29%	1731
	21st to end	Day	22% 16% 4 6% 5% 4 4 3 4 5% 25%	1600
December	1st to 10th	Day	23% 16% 4 8% 6% 5% 4 3 3 4 23%	1445
	11th to 20th	Day	22% 15% 4 8% 4 4 4 2 4 5% 27%	1796
	21st to end	Day	22% 19% 6% 9% 4 4 3 2 4 4 23%	2772
January	1st to 10th	Night	17% 16% 6% 10% 5% 5% 4 3 5% 5% 25%	4429
	11th to 20th	Night	12% 15% 5% 10% 7% 5% 5% 3 4 5% 28%	4440
	21st to end	Night	13% 13% 4 13% 7% 6% 5% 4 5% 6% 25%	4884
February	1st to 10th	Night	12% 15% 4 10% 7% 5% 5% 3 5% 5% 28%	2590
	11th to 20th	Night	12% 15% 4 13% 7% 5% 4 3 4 5% 29%	2283
	21st to end	Night	16% 12% 5% 9% 5% 5% 4 4 4 4 32%	1884
March	1st to 10th	Night	24% 12% 3 9% 5% 4 4 2 4 4 28%	3724
	11th to 20th	Night	17% 18% 4 9% 5% 5% 4 3 4 5% 26%	3709
	21st to end	Night	14% 10% 4 10% 5% 5% 5% 4 5% 5% 34%	3466
April	1st to 10th	Night	22% 12% 3 7% 4 4 3 4 5% 5% 32%	1900
	11th to 20th	Night	21% 9% 3 6% 5% 3 4 3 5% 5% 37%	1847
	21st to end	Night	23% 9% 3 6% 4 3 4 3 5% 6% 35%	1710
May	1st to 10th	Night	22% 9% 3 7% 4 4 5% 4 5% 5% 32%	2628
	11th to 20th	Night	22% 6% 1 5% 4 3 5% 3 6% 7% 37%	2495
	21st to end	Night	18% 6% 2 8% 6% 5% 4 4 5% 9% 33%	2738
June	1st to 10th	Night	21% 7% 2 6% 4 4 5% 4 6% 8% 34%	1520
	11th to 20th	Night	19% 7% 2 6% 4 5% 4 4 5% 8% 36%	1520
	21st to end	Night	20% 7% 3 7% 5% 5% 4 4 6% 7% 32%	1520
July	1st to 10th	Night	13% 7% 2 7% 6% 6% 6% 4 7% 8% 34%	2520
	11th to 20th	Night	17% 5% 2 6% 5% 5% 5% 3 6% 7% 39%	2520
	21st to end	Night	12% 4 2 5% 4 4 5% 4 6% 7% 47%	2739
August	1st to 10th	Night	15% 6% 3 7% 5% 5% 5% 5% 6% 7% 37%	2506
	11th to 20th	Night	17% 8% 3 6% 4 4 4 4 5% 6% 39%	2678
	21st to end	Night	18% 7% 3 8% 5% 4 4 3 4 6% 39%	3471
September	1st to 10th	Night	14% 5% 2 5% 5% 4 4 3 6% 6% 46%	1900
	11th to 20th	Night	15% 5% 2 5% 3 3 4 3 5% 6% 50%	2014
	21st to end	Night	18% 6% 2 5% 4 3 4 2 4 6% 45%	2090
October	1st to 10th	Night	18% 8% 2 7% 4 4 4 3 4 5% 40%	2170
	11th to 20th	Night	22% 8% 3 7% 4 3 4 3 4 6% 35%	2379
	21st to end	Night	25% 8% 3 6% 4 4 4 3 4 6% 32%	2717
November	1st to 10th	Night	18% 11% 4 7% 5% 4 4 3 5% 5% 34%	2537
	11th to 20th	Night	20% 10% 3 7% 5% 5% 5% 3 5% 5% 32%	2665
	21st to end	Night	24% 14% 4 7% 5% 4 4 3 4 5% 27%	2800
December	1st to 10th	Night	21% 15% 4 9% 6% 5% 4 4 4 5% 23%	2840
	11th to 20th	Night	23% 13% 4 10% 5% 4 3 3 3 4 26%	3384
	21st to end	Night	23% 19% 6% 9% 3 3 3 2 3 3 25%	4884

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	60% 1 15% 18% 5%	2518
	11th to 20th	Day	62% 2 8% 21% 7%	2520
	21st to end	Day	59% 2 10% 22% 6% 1	2772
February	1st to 10th	Day	62% 2 9% 17% 8% 2	1586
	11th to 20th	Day	60% 2 12% 15% 11% 1	1791
	21st to end	Day	61% 2 8% 16% 9% 3	1570
March	1st to 10th	Day	61% 1 11% 16% 10% 2	3119
	11th to 20th	Day	60% 2 9% 16% 11% 2	3245
	21st to end	Day	51% 2 7% 22% 15% 4	4166
April	1st to 10th	Day	57% 3 9% 16% 12% 2	2280
	11th to 20th	Day	50% 2 9% 23% 13% 3	2282
	21st to end	Day	56% 3 9% 18% 12% 3	2470
May	1st to 10th	Day	52% 1 10% 21% 14% 2	4343
	11th to 20th	Day	48% 2 18% 22% 9% 1	4402
	21st to end	Day	51% 2 9% 20% 16% 2	4837
June	1st to 10th	Day	55% 4 10% 20% 9% 2	2660
	11th to 20th	Day	47% 4 12% 23% 12% 2	2660
	21st to end	Day	57% 5% 10% 17% 10% 1	2660
July	1st to 10th	Day	46% 5% 15% 25% 8%	4370
	11th to 20th	Day	46% 7% 19% 22% 6%	4365
	21st to end	Day	42% 5% 16% 29% 8%	4661
August	1st to 10th	Day	47% 7% 19% 21% 7%	4409
	11th to 20th	Day	46% 6% 20% 22% 6%	4159
	21st to end	Day	45% 5% 15% 21% 14% 1	4181
September	1st to 10th	Day	41% 3 17% 26% 12% 1	2280
	11th to 20th	Day	39% 3 17% 29% 11% 1	2166
	21st to end	Day	45% 4 13% 27% 10%	2090
October	1st to 10th	Day	50% 5% 12% 27% 6%	3334
	11th to 20th	Day	50% 5% 17% 24% 3	2964
	21st to end	Day	48% 4 21% 20% 7% 1	3081
November	1st to 10th	Day	54% 3 12% 21% 9% 1	1761
	11th to 20th	Day	57% 3 11% 19% 10%	1731
	21st to end	Day	61% 5% 11% 17% 5% 1	1600
December	1st to 10th	Day	66% 2 9% 18% 5%	1445
	11th to 20th	Day	62% 2 7% 22% 7%	1797
	21st to end	Day	67% 2 8% 14% 7% 1	2772
January	1st to 10th	Night	64% 2 14% 15% 5%	4429
	11th to 20th	Night	61% 1 10% 21% 5% 1	4440
	21st to end	Night	62% 2 10% 17% 8% 1	4884
February	1st to 10th	Night	59% 3 10% 19% 9% 1	2590
	11th to 20th	Night	59% 3 9% 17% 11% 1	2285
	21st to end	Night	56% 3 7% 18% 14% 2	1884
March	1st to 10th	Night	62% 2 10% 14% 8% 3	3734
	11th to 20th	Night	63% 2 6% 17% 10% 2	3710
	21st to end	Night	54% 2 6% 24% 11% 3	3466
April	1st to 10th	Night	55% 2 8% 18% 15% 2	1900
	11th to 20th	Night	49% 3 8% 23% 14% 2	1847
	21st to end	Night	51% 4 7% 20% 16% 3	1710
May	1st to 10th	Night	56% 2 11% 21% 9% 2	2634
	11th to 20th	Night	48% 2 15% 21% 12% 2	2496
	21st to end	Night	50% 3 11% 18% 17% 1	2739
June	1st to 10th	Night	48% 3 13% 22% 13% 1	1520
	11th to 20th	Night	46% 4 11% 21% 13% 4	1520
	21st to end	Night	51% 5% 12% 18% 13%	1520
July	1st to 10th	Night	48% 5% 18% 20% 9% 1	2480
	11th to 20th	Night	44% 6% 19% 24% 6%	2472
	21st to end	Night	36% 5% 20% 27% 12%	2651
August	1st to 10th	Night	46% 5% 17% 24% 8%	2496
	11th to 20th	Night	47% 5% 19% 23% 7%	2703
	21st to end	Night	48% 3 13% 24% 13%	3471
September	1st to 10th	Night	39% 4 16% 27% 13% 1	1900
	11th to 20th	Night	35% 3 18% 32% 10% 1	2014
	21st to end	Night	43% 3 11% 31% 13%	2090
October	1st to 10th	Night	50% 5% 13% 24% 8%	3625
	11th to 20th	Night	47% 4 16% 28% 5%	3954
	21st to end	Night	46% 3 19% 19% 12% 1	4467
November	1st to 10th	Night	53% 4 12% 22% 8% 1	2537
	11th to 20th	Night	55% 4 11% 21% 10% 1	2665
	21st to end	Night	61% 3 10% 17% 8%	2800
December	1st to 10th	Night	65% 2 11% 16% 5%	2840
	11th to 20th	Night	64% 2 7% 19% 8%	3384
	21st to end	Night	67% 1 7% 18% 6% 1	4884

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	29% 11% 36% 18% 5% 1	180
	11th to 20th	Day	29% 11% 35% 19% 5% 1	180
	21st to end	Day	18% 10% 40% 21% 10% 1	198
February	1st to 10th	Day	28% 19% 37% 13% 2	211
	11th to 20th	Day	25% 15% 39% 17% 3	390
	21st to end	Day	27% 14% 36% 19% 4	382
March	1st to 10th	Day	25% 14% 33% 21% 6%	460
	11th to 20th	Day	25% 16% 34% 18% 5% 1	460
	21st to end	Day	27% 17% 28% 19% 7% 2	506
April	1st to 10th	Day	30% 12% 28% 23% 7% 1	460
	11th to 20th	Day	27% 14% 31% 20% 5% 3	452
	21st to end	Day	30% 12% 37% 14% 5% 2	460
May	1st to 10th	Day	28% 12% 34% 18% 7% 1	463
	11th to 20th	Day	20% 13% 31% 26% 8% 2	487
	21st to end	Day	23% 15% 35% 17% 9% 1	529
June	1st to 10th	Day	23% 10% 35% 22% 8% 2	490
	11th to 20th	Day	20% 13% 31% 23% 11% 3	490
	21st to end	Day	26% 10% 29% 23% 11% 2	490
July	1st to 10th	Day	16% 9% 32% 28% 13% 2	485
	11th to 20th	Day	17% 7% 30% 33% 11% 2	484
	21st to end	Day	17% 6% 29% 29% 16% 3	532
August	1st to 10th	Day	18% 6% 24% 31% 17% 3	486
	11th to 20th	Day	18% 4 22% 33% 17% 6%	479
	21st to end	Day	17% 10% 27% 22% 18% 6%	539
September	1st to 10th	Day	18% 8% 34% 22% 13% 5%	490
	11th to 20th	Day	17% 9% 23% 27% 16% 8%	490
	21st to end	Day	23% 10% 25% 23% 12% 6%	490
October	1st to 10th	Day	25% 11% 27% 23% 12% 2	490
	11th to 20th	Day	27% 11% 30% 20% 10% 1	437
	21st to end	Day	33% 9% 31% 20% 7%	429
November	1st to 10th	Day	28% 13% 29% 23% 6% 1	395
	11th to 20th	Day	27% 13% 31% 21% 7%	331
	21st to end	Day	28% 21% 31% 15% 5% 2	200
December	1st to 10th	Day	33% 11% 29% 19% 7% 1	190
	11th to 20th	Day	29% 15% 34% 17% 3 2	180
	21st to end	Day	34% 15% 29% 16% 5% 1	198
January	1st to 10th	Night	30% 8% 31% 26% 4	760
	11th to 20th	Night	29% 10% 32% 23% 7%	760
	21st to end	Night	18% 7% 34% 34% 6% 1	836
February	1st to 10th	Night	20% 10% 36% 28% 6% 1	760
	11th to 20th	Night	22% 12% 37% 24% 5% 1	743
	21st to end	Night	25% 10% 32% 27% 7%	628
March	1st to 10th	Night	24% 10% 32% 30% 4	760
	11th to 20th	Night	24% 12% 33% 25% 5% 1	760
	21st to end	Night	23% 12% 33% 25% 7% 1	836
April	1st to 10th	Night	30% 11% 27% 25% 7%	760
	11th to 20th	Night	27% 12% 29% 26% 5%	723
	21st to end	Night	29% 13% 29% 24% 5%	570
May	1st to 10th	Night	30% 10% 27% 27% 6%	455
	11th to 20th	Night	23% 8% 30% 31% 9%	374
	21st to end	Night	23% 5% 35% 28% 9%	411
June	1st to 10th	Night	24% 4 28% 34% 9% 1	380
	11th to 20th	Night	23% 5% 23% 39% 10% 1	380
	21st to end	Night	22% 6% 23% 37% 13%	380
July	1st to 10th	Night	15% 4 26% 37% 16% 1	370
	11th to 20th	Night	16% 1 24% 42% 15% 1	368
	21st to end	Night	17% 3 21% 42% 16% 1	416
August	1st to 10th	Night	14% 2 16% 47% 19% 1	378
	11th to 20th	Night	18% 4 19% 36% 21% 2	494
	21st to end	Night	19% 5% 23% 34% 18% 1	831
September	1st to 10th	Night	17% 4 28% 36% 14% 1	760
	11th to 20th	Night	18% 6% 23% 31% 21% 1	760
	21st to end	Night	23% 5% 27% 28% 16% 2	760
October	1st to 10th	Night	22% 9% 28% 31% 10% 1	760
	11th to 20th	Night	26% 8% 27% 28% 10% 1	760
	21st to end	Night	31% 8% 31% 25% 5%	836
November	1st to 10th	Night	26% 9% 30% 27% 7% 1	780
	11th to 20th	Night	26% 11% 30% 23% 11% 1	800
	21st to end	Night	33% 12% 25% 25% 6% 1	800
December	1st to 10th	Night	30% 8% 28% 26% 8%	833
	11th to 20th	Night	29% 9% 31% 23% 6% 1	805
	21st to end	Night	33% 11% 28% 23% 5%	836

Page generated at 2024-12-03 06:45:08. Version ac07

Copyright © 2024 Attilla Danko.