Beauceville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Beauceville clear sky chart from 2005-11-06 to 2024-01-22.

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	19% 11% 4 8% 6% 4 5% 4 5% 6% 28%	74619
	Night	17% 12% 5% 8% 7% 4 5% 4 5% 5% 29%	75307
Transparency	Day	57% 6% 11% 17% 8% 1	74324
	Night	58% 6% 11% 17% 8% 1	75137
Seeing	Day	27% 17% 28% 18% 8% 2	14180
	Night	25% 14% 28% 24% 8% 1	22845

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	15% 17% 8% 13% 10% 5% 5% 4 4 5% 13%	1517
	11th to 20th	Day	15% 18% 8% 12% 8% 4 4 4 4 4 21%	1520
	21st to end	Day	8% 13% 6% 12% 9% 4 6% 4 4 6% 27%	1592
February	1st to 10th	Day	12% 17% 7% 12% 11% 5% 6% 4 4 4 18%	1478
	11th to 20th	Day	13% 19% 8% 12% 7% 5% 5% 4 3 4 20%	1727
	21st to end	Day	13% 16% 6% 12% 8% 4 5% 5% 4 6% 23%	1480
March	1st to 10th	Day	15% 15% 7% 10% 8% 4 4 3 4 5% 26%	1797
	11th to 20th	Day	17% 15% 7% 8% 7% 3 4 4 4 4 28%	1908
	21st to end	Day	17% 12% 6% 9% 7% 4 5% 4 4 5% 28%	2281
April	1st to 10th	Day	22% 14% 5% 9% 6% 3 4 3 4 5% 26%	2160
	11th to 20th	Day	20% 11% 3 6% 5% 2 5% 4 3 5% 37%	2230
	21st to end	Day	25% 12% 3 7% 4 3 4 4 5% 5% 28%	2340
May	1st to 10th	Day	22% 10% 4 6% 6% 3 5% 4 4 5% 31%	2340
	11th to 20th	Day	22% 10% 3 5% 5% 3 5% 5% 5% 7% 31%	2478
	21st to end	Day	20% 6% 3 7% 6% 4 5% 6% 6% 8% 28%	2743
June	1st to 10th	Day	24% 8% 3 6% 6% 3 4 5% 7% 8% 26%	2700
	11th to 20th	Day	20% 6% 2 6% 6% 3 6% 5% 6% 8% 33%	2700
	21st to end	Day	21% 10% 4 9% 7% 4 5% 5% 5% 6% 25%	2700
July	1st to 10th	Day	16% 7% 3 7% 6% 5% 6% 6% 7% 8% 30%	2544
	11th to 20th	Day	16% 6% 3 7% 6% 4 6% 5% 7% 9% 31%	2520
	21st to end	Day	18% 7% 3 7% 6% 4 5% 6% 5% 8% 30%	2744
August	1st to 10th	Day	19% 7% 3 7% 6% 4 7% 5% 7% 8% 27%	2455
	11th to 20th	Day	16% 6% 3 7% 6% 3 6% 5% 5% 9% 32%	2304
	21st to end	Day	17% 7% 2 6% 5% 4 5% 6% 6% 8% 35%	2481
September	1st to 10th	Day	16% 7% 3 6% 6% 4 5% 6% 5% 7% 35%	2159
	11th to 20th	Day	19% 6% 3 5% 5% 2 4 4 5% 6% 42%	1980
	21st to end	Day	18% 8% 3 5% 3 3 4 4 6% 9% 35%	1980
October	1st to 10th	Day	20% 10% 3 6% 6% 4 4 5% 5% 6% 31%	1980
	11th to 20th	Day	21% 12% 3 8% 8% 3 6% 4 5% 5% 26%	1666
	21st to end	Day	26% 15% 5% 7% 7% 3 4 3 5% 5% 21%	1782
November	1st to 10th	Day	19% 14% 4 6% 7% 4 4 4 4 5% 28%	1671
	11th to 20th	Day	20% 13% 7% 9% 7% 3 4 3 4 5% 23%	1710
	21st to end	Day	19% 17% 4 10% 7% 3 5% 4 4 6% 20%	1421
December	1st to 10th	Day	22% 18% 7% 12% 7% 3 4 4 3 4 16%	1330
	11th to 20th	Day	19% 15% 7% 11% 8% 4 4 4 3 4 22%	1668
	21st to end	Day	22% 19% 6% 13% 7% 3 5% 3 3 3 17%	2533
January	1st to 10th	Night	15% 15% 9% 14% 10% 4 5% 4 4 4 15%	2649
	11th to 20th	Night	14% 16% 7% 12% 10% 4 5% 5% 4 3 20%	2660
	21st to end	Night	9% 12% 6% 12% 9% 4 6% 5% 5% 6% 25%	2798
February	1st to 10th	Night	12% 14% 6% 11% 10% 5% 7% 4 4 5% 22%	2480
	11th to 20th	Night	12% 15% 7% 12% 10% 5% 7% 4 3 4 21%	2116
	21st to end	Night	13% 15% 6% 9% 7% 3 4 5% 4 5% 28%	1776
March	1st to 10th	Night	14% 14% 6% 9% 7% 4 5% 4 4 6% 28%	2150
	11th to 20th	Night	16% 13% 4 9% 6% 3 5% 5% 5% 4 30%	2051
	21st to end	Night	17% 11% 5% 8% 5% 3 5% 4 5% 5% 31%	2071
April	1st to 10th	Night	21% 13% 5% 8% 5% 3 3 4 6% 5% 28%	1800
	11th to 20th	Night	18% 10% 3 6% 5% 4 4 5% 5% 6% 34%	1679
	21st to end	Night	22% 10% 5% 6% 6% 3 5% 5% 4 5% 30%	1620
May	1st to 10th	Night	22% 10% 5% 6% 6% 2 4 4 5% 6% 32%	1620
	11th to 20th	Night	19% 8% 4 6% 5% 4 4 5% 4 6% 35%	1430
	21st to end	Night	19% 7% 3 6% 5% 3 4 5% 5% 6% 38%	1528
June	1st to 10th	Night	22% 9% 3 7% 6% 3 6% 4 5% 6% 30%	1260
	11th to 20th	Night	17% 7% 3 6% 5% 4 5% 5% 5% 7% 37%	1260
	21st to end	Night	18% 7% 3 7% 6% 3 6% 4 5% 7% 33%	1260
July	1st to 10th	Night	14% 7% 3 6% 6% 3 5% 6% 6% 8% 36%	1411
	11th to 20th	Night	15% 5% 3 5% 5% 4 5% 5% 7% 9% 37%	1440
	21st to end	Night	14% 6% 4 6% 6% 4 5% 6% 7% 7% 36%	1574
August	1st to 10th	Night	14% 5% 2 6% 5% 3 5% 5% 6% 9% 41%	1464
	11th to 20th	Night	16% 7% 3 6% 5% 4 5% 6% 5% 8% 36%	1596
	21st to end	Night	14% 5% 3 4 5% 4 5% 5% 6% 7% 42%	1872
September	1st to 10th	Night	15% 6% 3 6% 6% 4 5% 5% 6% 7% 39%	1800
	11th to 20th	Night	17% 6% 2 5% 4 2 4 4 5% 6% 45%	1980
	21st to end	Night	17% 6% 3 5% 5% 3 4 5% 4 6% 42%	1980
October	1st to 10th	Night	18% 8% 3 6% 4 3 5% 5% 5% 7% 37%	1980
	11th to 20th	Night	21% 9% 3 7% 7% 4 5% 4 5% 6% 30%	2292
	21st to end	Night	22% 13% 4 8% 5% 3 4 4 4 5% 27%	2574
November	1st to 10th	Night	19% 12% 4 8% 5% 3 5% 4 5% 6% 29%	2407
	11th to 20th	Night	18% 11% 5% 8% 7% 4 5% 5% 5% 5% 29%	2470
	21st to end	Night	18% 16% 7% 9% 6% 3 4 4 4 5% 24%	2751
December	1st to 10th	Night	21% 15% 8% 10% 8% 5% 4 4 4 3 17%	2850
	11th to 20th	Night	20% 15% 7% 13% 8% 4 4 4 3 4 18%	3531
	21st to end	Night	23% 20% 5% 9% 6% 2 4 3 3 3 23%	5127

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	75% 4 8% 8% 4	1518
	11th to 20th	Day	69% 4 8% 13% 5% 1	1520
	21st to end	Day	61% 4 9% 16% 9% 1	1592
February	1st to 10th	Day	71% 4 7% 10% 6% 1	1478
	11th to 20th	Day	70% 4 9% 9% 7% 1	1736
	21st to end	Day	63% 4 8% 16% 7% 2	1480
March	1st to 10th	Day	62% 3 9% 13% 10% 2	1800
	11th to 20th	Day	60% 4 9% 15% 11% 1	1908
	21st to end	Day	59% 4 10% 15% 9% 2	2281
April	1st to 10th	Day	62% 4 9% 13% 9% 3	2160
	11th to 20th	Day	51% 5% 9% 21% 13% 1	2230
	21st to end	Day	59% 5% 9% 15% 10% 3	2340
May	1st to 10th	Day	55% 4 9% 16% 13% 2	2340
	11th to 20th	Day	52% 6% 11% 19% 10% 1	2482
	21st to end	Day	53% 8% 11% 17% 10% 1	2743
June	1st to 10th	Day	55% 7% 12% 20% 6% 1	2700
	11th to 20th	Day	49% 7% 12% 21% 10% 1	2700
	21st to end	Day	59% 8% 9% 15% 8%	2700
July	1st to 10th	Day	49% 10% 15% 20% 7%	2474
	11th to 20th	Day	48% 9% 16% 20% 7%	2445
	21st to end	Day	52% 9% 13% 20% 5% 1	2591
August	1st to 10th	Day	51% 11% 16% 19% 3	2441
	11th to 20th	Day	49% 10% 15% 18% 9%	2304
	21st to end	Day	47% 8% 12% 23% 9%	2481
September	1st to 10th	Day	46% 8% 14% 20% 10% 1	2159
	11th to 20th	Day	43% 6% 13% 26% 12% 1	1980
	21st to end	Day	45% 8% 13% 23% 10%	1980
October	1st to 10th	Day	53% 6% 11% 23% 7%	1980
	11th to 20th	Day	61% 7% 13% 17% 3	1666
	21st to end	Day	67% 5% 9% 15% 4 1	1782
November	1st to 10th	Day	60% 5% 12% 17% 6%	1671
	11th to 20th	Day	65% 4 10% 13% 6% 1	1710
	21st to end	Day	67% 7% 11% 12% 3	1421
December	1st to 10th	Day	73% 5% 8% 10% 4	1330
	11th to 20th	Day	68% 4 8% 13% 6%	1668
	21st to end	Day	73% 5% 6% 9% 5% 2	2533
January	1st to 10th	Night	74% 5% 8% 9% 4	2649
	11th to 20th	Night	70% 5% 8% 10% 5% 1	2660
	21st to end	Night	61% 6% 11% 13% 8% 2	2798
February	1st to 10th	Night	66% 5% 8% 13% 7% 1	2480
	11th to 20th	Night	70% 4 8% 11% 7% 1	2118
	21st to end	Night	61% 4 8% 15% 11% 1	1776
March	1st to 10th	Night	59% 4 10% 17% 8% 1	2160
	11th to 20th	Night	58% 5% 10% 13% 13% 2	2052
	21st to end	Night	56% 4 9% 19% 9% 3	2071
April	1st to 10th	Night	60% 5% 7% 15% 11% 3	1800
	11th to 20th	Night	51% 3 10% 21% 12% 2	1679
	21st to end	Night	58% 5% 9% 14% 11% 2	1620
May	1st to 10th	Night	54% 5% 10% 16% 14% 2	1620
	11th to 20th	Night	51% 6% 10% 20% 13% 1	1431
	21st to end	Night	48% 7% 12% 18% 13% 1	1529
June	1st to 10th	Night	55% 7% 10% 19% 8%	1260
	11th to 20th	Night	47% 6% 10% 23% 11% 2	1260
	21st to end	Night	50% 8% 14% 19% 9%	1260
July	1st to 10th	Night	42% 10% 18% 22% 8%	1371
	11th to 20th	Night	43% 10% 18% 21% 9%	1392
	21st to end	Night	46% 9% 16% 20% 8%	1486
August	1st to 10th	Night	39% 11% 20% 26% 4	1454
	11th to 20th	Night	45% 10% 16% 22% 6% 1	1596
	21st to end	Night	40% 8% 15% 27% 9%	1872
September	1st to 10th	Night	43% 7% 16% 24% 9% 1	1800
	11th to 20th	Night	41% 5% 17% 28% 9% 1	1980
	21st to end	Night	42% 8% 13% 24% 13%	1980
October	1st to 10th	Night	47% 6% 13% 23% 11%	1980
	11th to 20th	Night	56% 6% 13% 19% 5%	2292
	21st to end	Night	61% 5% 11% 15% 7%	2574
November	1st to 10th	Night	57% 6% 14% 17% 6%	2407
	11th to 20th	Night	58% 5% 13% 14% 9% 1	2470
	21st to end	Night	64% 6% 11% 14% 4	2751
December	1st to 10th	Night	73% 5% 9% 10% 3	2850
	11th to 20th	Night	71% 5% 8% 11% 4	3532
	21st to end	Night	68% 5% 7% 14% 6%	5127

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% 19% 36% 15% 2	180
	11th to 20th	Day	34% 22% 31% 10% 3	180
	21st to end	Day	20% 28% 33% 15% 4 1	178
February	1st to 10th	Day	36% 24% 27% 9% 4	198
	11th to 20th	Day	28% 25% 32% 13% 2	407
	21st to end	Day	27% 27% 27% 16% 3	346
March	1st to 10th	Day	29% 24% 29% 13% 5%	420
	11th to 20th	Day	30% 22% 27% 15% 5% 1	420
	21st to end	Day	32% 21% 23% 14% 7% 2	462
April	1st to 10th	Day	39% 17% 26% 12% 6% 1	420
	11th to 20th	Day	34% 20% 24% 15% 6% 1	412
	21st to end	Day	34% 20% 28% 11% 5% 1	420
May	1st to 10th	Day	32% 18% 30% 16% 3 1	423
	11th to 20th	Day	28% 17% 30% 19% 4 1	447
	21st to end	Day	21% 22% 35% 15% 6% 1	503
June	1st to 10th	Day	28% 14% 30% 20% 7% 1	630
	11th to 20th	Day	23% 16% 25% 24% 11% 1	630
	21st to end	Day	24% 13% 31% 20% 10% 2	630
July	1st to 10th	Day	21% 11% 34% 24% 9% 1	469
	11th to 20th	Day	19% 12% 37% 20% 11% 1	444
	21st to end	Day	23% 10% 34% 23% 9% 1	488
August	1st to 10th	Day	19% 13% 31% 24% 11% 2	446
	11th to 20th	Day	22% 9% 28% 25% 14% 2	439
	21st to end	Day	25% 13% 25% 20% 12% 6%	495
September	1st to 10th	Day	19% 14% 30% 21% 11% 5%	450
	11th to 20th	Day	25% 11% 26% 18% 15% 5%	450
	21st to end	Day	21% 16% 25% 20% 11% 6%	450
October	1st to 10th	Day	24% 18% 22% 21% 12% 4	450
	11th to 20th	Day	34% 14% 26% 14% 10% 1	367
	21st to end	Day	37% 17% 26% 16% 4	396
November	1st to 10th	Day	34% 14% 28% 19% 4	365
	11th to 20th	Day	28% 21% 25% 16% 9% 1	370
	21st to end	Day	35% 21% 25% 15% 3 1	237
December	1st to 10th	Day	36% 18% 25% 16% 4 2	180
	11th to 20th	Day	38% 22% 23% 13% 2 1	180
	21st to end	Day	37% 21% 26% 12% 4 1	198
January	1st to 10th	Night	27% 21% 31% 18% 3	760
	11th to 20th	Night	28% 19% 33% 16% 4	760
	21st to end	Night	20% 16% 35% 23% 5% 1	800
February	1st to 10th	Night	22% 23% 34% 18% 5%	720
	11th to 20th	Night	25% 22% 32% 17% 3	703
	21st to end	Night	26% 17% 31% 22% 3	592
March	1st to 10th	Night	23% 19% 34% 21% 3	720
	11th to 20th	Night	26% 20% 32% 17% 5% 1	720
	21st to end	Night	25% 17% 27% 24% 6% 1	792
April	1st to 10th	Night	33% 16% 27% 19% 5%	720
	11th to 20th	Night	26% 14% 28% 25% 7%	615
	21st to end	Night	29% 17% 29% 20% 6%	540
May	1st to 10th	Night	27% 13% 28% 24% 8% 1	540
	11th to 20th	Night	24% 9% 31% 30% 5% 1	369
	21st to end	Night	23% 8% 31% 28% 9%	389
June	1st to 10th	Night	26% 8% 28% 30% 8% 1	360
	11th to 20th	Night	21% 8% 24% 33% 14%	360
	21st to end	Night	20% 8% 29% 31% 12%	360
July	1st to 10th	Night	17% 6% 33% 31% 12% 1	350
	11th to 20th	Night	18% 3 25% 40% 14%	348
	21st to end	Night	15% 5% 25% 42% 12%	394
August	1st to 10th	Night	17% 3 19% 40% 20%	390
	11th to 20th	Night	17% 5% 26% 33% 18% 1	532
	21st to end	Night	16% 7% 28% 31% 17% 2	684
September	1st to 10th	Night	18% 8% 29% 30% 14% 2	720
	11th to 20th	Night	23% 9% 21% 30% 17% 2	720
	21st to end	Night	22% 9% 28% 24% 15% 1	720
October	1st to 10th	Night	24% 10% 25% 28% 12%	720
	11th to 20th	Night	29% 12% 26% 21% 10% 1	720
	21st to end	Night	33% 17% 26% 19% 6%	792
November	1st to 10th	Night	31% 14% 25% 24% 6%	740
	11th to 20th	Night	28% 15% 28% 19% 10% 1	760
	21st to end	Night	31% 17% 28% 19% 5% 1	833
December	1st to 10th	Night	33% 17% 26% 19% 4	850
	11th to 20th	Night	30% 21% 23% 20% 6%	850
	21st to end	Night	34% 20% 24% 17% 4	902

Page generated at 2024-01-19 09:28:31. Version ac07

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