Rivière-à-Pierre Village
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rivière-à-Pierre Village clear sky chart from 2005-11-06 to 2024-01-17.

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	21% 10% 4 7% 6% 3 5% 4 5% 6% 28%	74568
	Night	20% 11% 4 7% 6% 3 5% 4 5% 6% 29%	75233
Transparency	Day	58% 3 11% 19% 9% 1	74273
	Night	57% 3 11% 20% 9% 1	75063
Seeing	Day	28% 16% 30% 17% 7% 1	13854
	Night	27% 13% 27% 24% 8% 1	22668

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	18% 17% 7% 11% 9% 4 5% 5% 5% 3 17%	1517
	11th to 20th	Day	17% 17% 7% 9% 7% 2 5% 4 4 4 23%	1488
	21st to end	Day	12% 12% 7% 10% 7% 4 6% 5% 5% 7% 25%	1584
February	1st to 10th	Day	11% 17% 6% 11% 10% 5% 5% 5% 4 5% 21%	1465
	11th to 20th	Day	12% 17% 8% 10% 6% 4 4 4 5% 7% 23%	1702
	21st to end	Day	14% 16% 6% 12% 7% 4 5% 5% 4 4 24%	1480
March	1st to 10th	Day	16% 12% 6% 10% 6% 4 5% 4 5% 5% 29%	1797
	11th to 20th	Day	18% 13% 6% 8% 7% 4 4 4 4 5% 29%	1854
	21st to end	Day	16% 12% 4 8% 7% 4 5% 4 4 5% 30%	2358
April	1st to 10th	Day	23% 13% 4 9% 6% 3 4 3 4 4 27%	2160
	11th to 20th	Day	22% 10% 3 5% 5% 3 4 4 3 5% 35%	2188
	21st to end	Day	23% 12% 3 6% 6% 4 4 4 4 5% 30%	2340
May	1st to 10th	Day	23% 9% 3 5% 6% 3 5% 4 4 5% 33%	2448
	11th to 20th	Day	19% 8% 3 7% 5% 3 5% 4 6% 6% 33%	2478
	21st to end	Day	22% 7% 3 7% 5% 3 5% 4 5% 7% 30%	2725
June	1st to 10th	Day	24% 7% 3 7% 6% 3 5% 6% 6% 7% 25%	2633
	11th to 20th	Day	21% 7% 3 6% 5% 4 6% 5% 5% 8% 32%	2700
	21st to end	Day	26% 8% 4 6% 6% 4 5% 4 6% 6% 26%	2642
July	1st to 10th	Day	19% 7% 3 6% 7% 4 6% 6% 5% 8% 30%	2520
	11th to 20th	Day	19% 6% 3 6% 6% 4 5% 6% 7% 9% 28%	2520
	21st to end	Day	17% 6% 3 6% 7% 5% 6% 6% 7% 8% 28%	2744
August	1st to 10th	Day	19% 7% 3 8% 7% 4 6% 6% 7% 8% 25%	2506
	11th to 20th	Day	19% 7% 3 6% 5% 4 5% 6% 6% 8% 32%	2335
	21st to end	Day	18% 7% 3 5% 6% 4 6% 5% 7% 8% 32%	2422
September	1st to 10th	Day	20% 6% 2 5% 5% 3 5% 5% 6% 7% 36%	2160
	11th to 20th	Day	20% 6% 3 5% 5% 3 4 4 6% 6% 40%	2034
	21st to end	Day	26% 7% 2 4 4 3 4 4 5% 6% 35%	1980
October	1st to 10th	Day	27% 7% 3 6% 5% 3 5% 3 4 6% 30%	1929
	11th to 20th	Day	28% 11% 3 7% 7% 4 5% 4 4 6% 21%	1679
	21st to end	Day	30% 13% 3 6% 6% 3 5% 3 4 7% 21%	1782
November	1st to 10th	Day	22% 12% 4 6% 7% 4 4 3 4 5% 29%	1671
	11th to 20th	Day	23% 15% 7% 8% 7% 3 4 3 3 5% 23%	1658
	21st to end	Day	22% 18% 5% 8% 7% 3 3 5% 5% 6% 19%	1440
December	1st to 10th	Day	25% 17% 5% 8% 6% 3 3 3 3 4 21%	1330
	11th to 20th	Day	23% 15% 5% 9% 7% 3 3 3 4 4 25%	1668
	21st to end	Day	21% 19% 7% 8% 5% 2 4 4 4 5% 20%	2631
January	1st to 10th	Night	18% 20% 7% 9% 7% 3 5% 4 6% 6% 15%	2649
	11th to 20th	Night	17% 17% 6% 10% 5% 3 4 4 5% 5% 23%	2616
	21st to end	Night	10% 14% 5% 9% 9% 4 5% 4 5% 6% 28%	2772
February	1st to 10th	Night	12% 13% 6% 10% 9% 4 5% 4 4 7% 26%	2493
	11th to 20th	Night	14% 15% 6% 11% 7% 4 6% 4 4 5% 24%	2143
	21st to end	Night	14% 15% 6% 9% 6% 3 4 4 5% 6% 28%	1776
March	1st to 10th	Night	15% 14% 5% 8% 8% 3 6% 4 4 6% 28%	2150
	11th to 20th	Night	17% 13% 5% 7% 6% 4 6% 4 4 6% 29%	2105
	21st to end	Night	15% 11% 4 7% 5% 3 5% 5% 5% 6% 34%	1997
April	1st to 10th	Night	24% 13% 4 8% 5% 3 4 4 4 5% 26%	1800
	11th to 20th	Night	21% 8% 3 5% 6% 3 4 4 5% 6% 36%	1720
	21st to end	Night	23% 11% 3 6% 5% 2 4 3 5% 6% 34%	1620
May	1st to 10th	Night	23% 9% 3 5% 5% 3 4 3 4 5% 35%	1527
	11th to 20th	Night	19% 8% 3 6% 5% 3 5% 4 4 6% 37%	1415
	21st to end	Night	24% 6% 3 5% 4 2 4 4 4 6% 36%	1550
June	1st to 10th	Night	23% 6% 3 6% 5% 3 4 5% 6% 7% 30%	1321
	11th to 20th	Night	21% 6% 3 5% 4 2 5% 5% 5% 9% 35%	1260
	21st to end	Night	23% 8% 3 6% 6% 3 5% 4 7% 7% 29%	1312
July	1st to 10th	Night	18% 6% 3 6% 4 3 6% 5% 6% 8% 35%	1440
	11th to 20th	Night	16% 5% 2 6% 5% 4 6% 6% 6% 8% 36%	1440
	21st to end	Night	16% 6% 2 5% 6% 4 6% 5% 6% 7% 37%	1574
August	1st to 10th	Night	15% 5% 2 5% 5% 4 5% 7% 6% 10% 37%	1432
	11th to 20th	Night	16% 6% 3 6% 6% 4 5% 5% 5% 7% 36%	1546
	21st to end	Night	19% 6% 2 5% 4 3 4 4 5% 9% 39%	1931
September	1st to 10th	Night	19% 6% 2 5% 5% 2 3 4 4 6% 43%	1800
	11th to 20th	Night	19% 6% 2 4 4 3 5% 3 5% 6% 42%	1926
	21st to end	Night	22% 6% 2 4 4 3 4 3 4 6% 41%	1980
October	1st to 10th	Night	21% 8% 3 5% 4 3 3 4 5% 6% 38%	2029
	11th to 20th	Night	27% 9% 3 5% 5% 3 4 3 4 5% 30%	2281
	21st to end	Night	28% 11% 3 6% 5% 3 4 4 4 7% 25%	2574
November	1st to 10th	Night	21% 12% 4 7% 6% 3 4 3 5% 6% 29%	2407
	11th to 20th	Night	22% 12% 4 7% 5% 3 4 4 4 6% 27%	2518
	21st to end	Night	24% 15% 4 7% 5% 3 5% 4 4 5% 23%	2736
December	1st to 10th	Night	24% 15% 6% 10% 6% 3 5% 4 3 5% 19%	2850
	11th to 20th	Night	22% 14% 5% 10% 7% 3 4 4 4 4 22%	3531
	21st to end	Night	22% 20% 6% 8% 6% 3 4 3 3 4 22%	5012

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	71% 3 6% 13% 6%	1518
	11th to 20th	Day	65% 3 9% 15% 7% 1	1488
	21st to end	Day	59% 3 6% 18% 13% 1	1584
February	1st to 10th	Day	66% 3 7% 14% 8% 2	1465
	11th to 20th	Day	64% 3 10% 13% 10% 1	1711
	21st to end	Day	63% 3 6% 17% 8% 2	1480
March	1st to 10th	Day	60% 2 7% 17% 12% 2	1800
	11th to 20th	Day	59% 3 8% 16% 13% 1	1854
	21st to end	Day	57% 3 7% 18% 13% 2	2358
April	1st to 10th	Day	63% 3 9% 14% 9% 3	2160
	11th to 20th	Day	54% 2 8% 22% 11% 3	2188
	21st to end	Day	59% 2 8% 16% 13% 2	2340
May	1st to 10th	Day	54% 3 8% 18% 14% 3	2448
	11th to 20th	Day	52% 3 9% 21% 14% 1	2482
	21st to end	Day	54% 5% 8% 18% 13% 1	2725
June	1st to 10th	Day	58% 4 9% 20% 7% 2	2633
	11th to 20th	Day	51% 4 12% 20% 11% 2	2700
	21st to end	Day	59% 4 12% 15% 10%	2642
July	1st to 10th	Day	51% 5% 15% 23% 6%	2450
	11th to 20th	Day	51% 5% 15% 22% 8%	2445
	21st to end	Day	54% 5% 16% 19% 6%	2591
August	1st to 10th	Day	54% 6% 17% 19% 3	2492
	11th to 20th	Day	50% 4 18% 21% 7%	2335
	21st to end	Day	49% 5% 13% 23% 8%	2422
September	1st to 10th	Day	47% 4 15% 25% 9%	2160
	11th to 20th	Day	46% 3 16% 25% 10%	2034
	21st to end	Day	52% 3 12% 25% 8%	1980
October	1st to 10th	Day	56% 3 12% 20% 9%	1929
	11th to 20th	Day	66% 4 12% 17% 2	1679
	21st to end	Day	65% 3 10% 16% 5% 1	1782
November	1st to 10th	Day	59% 3 10% 20% 7% 1	1671
	11th to 20th	Day	67% 2 9% 16% 5% 1	1658
	21st to end	Day	67% 5% 11% 15% 3	1440
December	1st to 10th	Day	69% 2 9% 16% 5%	1330
	11th to 20th	Day	65% 2 6% 20% 7%	1668
	21st to end	Day	68% 3 8% 14% 7% 1	2631
January	1st to 10th	Night	70% 2 7% 16% 5%	2649
	11th to 20th	Night	64% 3 10% 14% 8% 1	2616
	21st to end	Night	58% 3 8% 18% 12% 1	2772
February	1st to 10th	Night	59% 3 8% 19% 9% 1	2493
	11th to 20th	Night	64% 2 10% 14% 9% 1	2145
	21st to end	Night	59% 3 7% 18% 13% 1	1776
March	1st to 10th	Night	59% 4 8% 17% 11% 2	2160
	11th to 20th	Night	59% 3 8% 15% 14% 2	2106
	21st to end	Night	52% 3 8% 21% 12% 4	1997
April	1st to 10th	Night	61% 3 7% 16% 11% 2	1800
	11th to 20th	Night	50% 3 8% 23% 14% 2	1720
	21st to end	Night	54% 3 9% 20% 13% 2	1620
May	1st to 10th	Night	53% 3 9% 19% 14% 3	1527
	11th to 20th	Night	49% 3 11% 21% 14% 2	1416
	21st to end	Night	50% 4 10% 20% 14% 2	1551
June	1st to 10th	Night	53% 3 13% 22% 9% 1	1321
	11th to 20th	Night	47% 5% 12% 21% 12% 3	1260
	21st to end	Night	55% 4 13% 18% 11%	1312
July	1st to 10th	Night	45% 6% 19% 23% 8%	1400
	11th to 20th	Night	45% 5% 19% 23% 8% 1	1392
	21st to end	Night	47% 6% 16% 24% 7%	1486
August	1st to 10th	Night	42% 7% 21% 25% 5%	1422
	11th to 20th	Night	48% 4 21% 21% 6%	1546
	21st to end	Night	43% 5% 16% 29% 7%	1931
September	1st to 10th	Night	44% 3 14% 27% 10% 1	1800
	11th to 20th	Night	44% 3 18% 28% 7% 1	1926
	21st to end	Night	46% 4 12% 29% 10%	1980
October	1st to 10th	Night	48% 3 12% 25% 12% 1	2029
	11th to 20th	Night	58% 3 13% 20% 6%	2281
	21st to end	Night	60% 4 11% 19% 6% 1	2574
November	1st to 10th	Night	58% 3 12% 19% 7% 1	2407
	11th to 20th	Night	59% 4 11% 19% 8%	2518
	21st to end	Night	64% 3 10% 16% 6%	2736
December	1st to 10th	Night	70% 2 10% 14% 5%	2850
	11th to 20th	Night	67% 3 5% 17% 8%	3532
	21st to end	Night	69% 2 6% 16% 6% 1	5012

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	30% 19% 36% 12% 3	180
	11th to 20th	Day	28% 16% 36% 16% 3	172
	21st to end	Day	19% 18% 43% 13% 6% 1	176
February	1st to 10th	Day	31% 25% 34% 7% 1 1	172
	11th to 20th	Day	28% 26% 32% 12% 2	370
	21st to end	Day	27% 27% 27% 13% 4	346
March	1st to 10th	Day	28% 20% 32% 15% 4	420
	11th to 20th	Day	31% 20% 29% 15% 3 1	420
	21st to end	Day	26% 24% 27% 16% 6% 1	462
April	1st to 10th	Day	35% 16% 30% 14% 4 1	420
	11th to 20th	Day	33% 19% 28% 12% 4 2	412
	21st to end	Day	34% 19% 29% 11% 5% 1	420
May	1st to 10th	Day	34% 17% 32% 13% 5%	423
	11th to 20th	Day	26% 19% 31% 19% 4 1	447
	21st to end	Day	28% 23% 29% 16% 4	485
June	1st to 10th	Day	27% 16% 33% 17% 7% 1	563
	11th to 20th	Day	26% 14% 29% 21% 8% 1	630
	21st to end	Day	26% 11% 31% 22% 9% 2	572
July	1st to 10th	Day	22% 12% 35% 21% 9% 1	445
	11th to 20th	Day	21% 10% 36% 25% 7% 1	444
	21st to end	Day	21% 11% 33% 25% 8% 2	488
August	1st to 10th	Day	21% 9% 33% 26% 9% 2	446
	11th to 20th	Day	23% 8% 29% 25% 12% 3	439
	21st to end	Day	24% 13% 28% 19% 11% 5%	495
September	1st to 10th	Day	24% 11% 33% 20% 10% 2	450
	11th to 20th	Day	23% 10% 28% 24% 10% 5%	450
	21st to end	Day	25% 17% 26% 16% 11% 5%	450
October	1st to 10th	Day	29% 17% 27% 16% 10% 2	450
	11th to 20th	Day	34% 17% 28% 13% 7% 1	390
	21st to end	Day	39% 15% 24% 17% 5%	396
November	1st to 10th	Day	35% 16% 25% 16% 6% 1	365
	11th to 20th	Day	32% 18% 31% 14% 4 1	318
	21st to end	Day	38% 18% 27% 15% 1	180
December	1st to 10th	Day	32% 17% 33% 13% 6%	180
	11th to 20th	Day	36% 22% 28% 11% 2 1	180
	21st to end	Day	37% 22% 24% 13% 4 1	198
January	1st to 10th	Night	29% 16% 32% 18% 4 1	760
	11th to 20th	Night	28% 18% 29% 19% 5%	748
	21st to end	Night	19% 17% 32% 24% 6% 1	792
February	1st to 10th	Night	20% 19% 34% 20% 6%	720
	11th to 20th	Night	25% 17% 35% 18% 4	703
	21st to end	Night	24% 18% 31% 21% 6% 1	592
March	1st to 10th	Night	24% 17% 34% 20% 5%	720
	11th to 20th	Night	28% 17% 31% 18% 5% 1	720
	21st to end	Night	25% 19% 26% 22% 7% 1	792
April	1st to 10th	Night	33% 12% 29% 19% 6% 1	720
	11th to 20th	Night	28% 15% 27% 24% 5% 1	656
	21st to end	Night	30% 19% 28% 17% 5%	540
May	1st to 10th	Night	28% 15% 28% 21% 8%	447
	11th to 20th	Night	26% 10% 27% 27% 9%	354
	21st to end	Night	28% 10% 32% 22% 8% 1	389
June	1st to 10th	Night	25% 8% 27% 32% 8%	360
	11th to 20th	Night	24% 8% 22% 36% 10%	360
	21st to end	Night	24% 5% 23% 35% 13% 1	360
July	1st to 10th	Night	19% 6% 27% 35% 13%	350
	11th to 20th	Night	18% 2 22% 41% 17% 1	348
	21st to end	Night	18% 4 22% 37% 17% 1	394
August	1st to 10th	Night	18% 4 16% 45% 16%	358
	11th to 20th	Night	19% 6% 22% 34% 18% 1	482
	21st to end	Night	22% 10% 20% 31% 15% 2	743
September	1st to 10th	Night	22% 7% 28% 32% 11% 1	720
	11th to 20th	Night	24% 7% 24% 28% 16% 2	720
	21st to end	Night	24% 10% 27% 23% 14% 2	720
October	1st to 10th	Night	26% 12% 24% 27% 10% 1	720
	11th to 20th	Night	32% 10% 25% 23% 8% 1	720
	21st to end	Night	35% 13% 25% 22% 6%	792
November	1st to 10th	Night	30% 13% 28% 21% 7% 1	740
	11th to 20th	Night	30% 15% 29% 17% 8% 2	760
	21st to end	Night	33% 18% 22% 21% 5%	796
December	1st to 10th	Night	33% 16% 25% 21% 5%	850
	11th to 20th	Night	30% 18% 26% 20% 5% 1	850
	21st to end	Night	34% 17% 30% 15% 3	872

Page generated at 2024-01-14 09:55:04. Version ac07

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