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 2026-05-02.

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 9% 5% 5% 5% 4 5% 6% 28%	131201
	Night	18% 13% 4 10% 6% 5% 5% 3 5% 6% 27%	131272
Transparency	Day	58% 3 11% 18% 9% 1	134644
	Night	59% 2 11% 18% 8% 1	135917
Seeing	Day	29% 16% 30% 17% 6% 1	16782
	Night	27% 13% 27% 24% 8% 1	25597

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	14% 16% 6% 16% 7% 5% 6% 4 5% 5% 17%	4661
	11th to 20th	Day	12% 17% 8% 19% 10% 5% 4 2 3 4 18%	4650
	21st to end	Day	8% 10% 7% 12% 6% 7% 6% 5% 7% 8% 24%	5124
February	1st to 10th	Day	10% 16% 5% 12% 9% 6% 5% 3 4 5% 24%	1710
	11th to 20th	Day	11% 18% 7% 11% 6% 6% 4 3 5% 7% 23%	1995
	21st to end	Day	13% 17% 5% 12% 5% 5% 5% 3 4 4 25%	1730
March	1st to 10th	Day	21% 17% 5% 11% 5% 3 3 2 3 4 24%	4576
	11th to 20th	Day	15% 16% 5% 10% 6% 5% 4 3 4 5% 27%	4761
	21st to end	Day	17% 16% 4 8% 5% 4 3 3 4 5% 31%	6055
April	1st to 10th	Day	22% 15% 3 9% 5% 4 3 3 3 4 27%	2520
	11th to 20th	Day	23% 11% 3 7% 4 4 4 3 4 5% 33%	2558
	21st to end	Day	22% 12% 3 8% 5% 5% 4 3 4 5% 29%	2730
May	1st to 10th	Day	28% 10% 3 6% 4 4 4 3 5% 6% 27%	6175
	11th to 20th	Day	24% 7% 3 6% 4 4 4 4 6% 7% 32%	6318
	21st to end	Day	21% 10% 3 8% 5% 5% 5% 4 5% 6% 27%	6949
June	1st to 10th	Day	24% 8% 3 8% 5% 4 5% 4 6% 6% 26%	2927
	11th to 20th	Day	21% 7% 3 6% 5% 5% 5% 4 6% 8% 31%	3000
	21st to end	Day	25% 9% 3 6% 5% 5% 4 3 6% 6% 26%	2934
July	1st to 10th	Day	18% 8% 3 8% 6% 6% 6% 5% 7% 8% 26%	6360
	11th to 20th	Day	18% 7% 3 7% 5% 5% 5% 5% 7% 9% 29%	6360
	21st to end	Day	12% 5% 2 6% 5% 6% 6% 4 7% 9% 37%	6926
August	1st to 10th	Day	16% 7% 3 8% 6% 6% 6% 4 7% 9% 28%	4563
	11th to 20th	Day	22% 7% 3 6% 4 5% 5% 5% 6% 8% 29%	4221
	21st to end	Day	21% 7% 3 6% 5% 4 5% 4 6% 7% 32%	4388
September	1st to 10th	Day	18% 6% 2 6% 4 4 5% 4 6% 8% 37%	2400
	11th to 20th	Day	18% 6% 2 5% 4 4 4 3 6% 6% 42%	2259
	21st to end	Day	25% 8% 2 5% 3 4 3 4 5% 6% 35%	2200
October	1st to 10th	Day	25% 7% 3 7% 4 4 5% 3 5% 6% 31%	2143
	11th to 20th	Day	26% 11% 3 8% 6% 5% 5% 3 4 6% 23%	1865
	21st to end	Day	29% 14% 3 7% 5% 3 4 2 4 6% 22%	1980
November	1st to 10th	Day	22% 14% 4 7% 6% 5% 3 3 4 5% 27%	1851
	11th to 20th	Day	21% 17% 7% 9% 6% 4 4 2 3 5% 23%	1832
	21st to end	Day	20% 21% 5% 10% 5% 4 3 4 5% 5% 17%	1591
December	1st to 10th	Day	20% 18% 6% 10% 7% 5% 5% 3 4 4 18%	2350
	11th to 20th	Day	21% 15% 7% 10% 7% 4 3 2 4 5% 24%	2688
	21st to end	Day	19% 18% 5% 8% 5% 4 5% 4 4 5% 23%	3851
January	1st to 10th	Night	12% 19% 8% 16% 7% 5% 5% 3 5% 5% 16%	8234
	11th to 20th	Night	11% 22% 8% 17% 8% 4 4 3 4 4 15%	8235
	21st to end	Night	7% 13% 6% 13% 8% 8% 6% 4 7% 7% 23%	9057
February	1st to 10th	Night	11% 13% 6% 12% 7% 5% 5% 3 5% 6% 28%	2908
	11th to 20th	Night	13% 16% 5% 12% 7% 5% 5% 3 5% 5% 24%	2510
	21st to end	Night	14% 16% 6% 8% 6% 4 4 3 5% 5% 28%	2076
March	1st to 10th	Night	21% 15% 5% 11% 7% 4 5% 3 4 5% 21%	5484
	11th to 20th	Night	15% 13% 5% 10% 5% 6% 5% 4 5% 6% 24%	5404
	21st to end	Night	16% 16% 4 8% 5% 5% 4 3 5% 5% 29%	5104
April	1st to 10th	Night	22% 14% 3 9% 4 4 4 3 4 6% 27%	2100
	11th to 20th	Night	21% 10% 3 6% 5% 4 4 3 5% 6% 33%	2010
	21st to end	Night	22% 11% 2 7% 4 3 4 2 5% 5% 35%	1890
May	1st to 10th	Night	25% 10% 3 7% 5% 4 4 3 4 5% 30%	3817
	11th to 20th	Night	25% 6% 2 6% 4 3 4 3 5% 7% 34%	3575
	21st to end	Night	20% 8% 3 7% 5% 5% 5% 4 5% 7% 30%	3926
June	1st to 10th	Night	22% 8% 2 7% 4 4 4 4 6% 7% 32%	1467
	11th to 20th	Night	21% 7% 2 6% 4 3 5% 4 5% 8% 35%	1400
	21st to end	Night	24% 9% 2 7% 5% 4 4 3 6% 6% 29%	1458
July	1st to 10th	Night	15% 6% 3 7% 6% 6% 6% 5% 8% 10% 30%	3600
	11th to 20th	Night	19% 7% 2 7% 4 4 4 4 5% 7% 36%	3600
	21st to end	Night	12% 5% 2 6% 5% 5% 5% 4 6% 7% 45%	3926
August	1st to 10th	Night	15% 8% 3 6% 5% 5% 5% 4 5% 7% 36%	2586
	11th to 20th	Night	19% 8% 3 6% 5% 4 5% 4 5% 7% 33%	2793
	21st to end	Night	19% 7% 3 7% 4 5% 4 4 5% 7% 34%	3507
September	1st to 10th	Night	19% 6% 2 6% 4 4 3 3 4 6% 44%	2000
	11th to 20th	Night	17% 6% 2 5% 3 4 4 3 5% 6% 43%	2140
	21st to end	Night	21% 6% 2 5% 4 4 4 2 4 6% 41%	2200
October	1st to 10th	Night	20% 9% 2 6% 3 4 3 3 5% 6% 39%	2255
	11th to 20th	Night	26% 9% 3 6% 4 4 5% 2 5% 5% 32%	2535
	21st to end	Night	27% 11% 3 7% 4 4 4 3 4 7% 25%	2860
November	1st to 10th	Night	21% 13% 4 8% 5% 4 4 3 5% 6% 28%	2667
	11th to 20th	Night	20% 13% 5% 9% 5% 4 4 3 4 6% 27%	2784
	21st to end	Night	23% 18% 4 9% 5% 4 4 3 4 4 21%	3025
December	1st to 10th	Night	16% 14% 8% 15% 9% 5% 4 3 3 4 18%	5060
	11th to 20th	Night	23% 15% 4 11% 8% 4 4 3 3 3 20%	5741
	21st to end	Night	21% 18% 5% 10% 5% 3 4 3 3 3 25%	7338

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% 1 8% 14% 6%	4662
	11th to 20th	Day	74% 1 5% 13% 7% 1	4680
	21st to end	Day	57% 2 6% 20% 14%	5124
February	1st to 10th	Day	64% 3 6% 16% 9% 2	1710
	11th to 20th	Day	63% 2 9% 16% 10% 1	2004
	21st to end	Day	62% 3 6% 17% 9% 2	1730
March	1st to 10th	Day	68% 1 6% 11% 11% 3	4579
	11th to 20th	Day	61% 2 12% 14% 11% 1	4761
	21st to end	Day	58% 1 4 17% 16% 3	6055
April	1st to 10th	Day	62% 2 9% 15% 10% 3	2520
	11th to 20th	Day	56% 2 8% 21% 11% 2	2558
	21st to end	Day	58% 2 8% 17% 12% 2	2730
May	1st to 10th	Day	60% 2 7% 16% 14% 1	6186
	11th to 20th	Day	53% 3 15% 20% 8% 2	6322
	21st to end	Day	59% 3 7% 15% 13% 3	6949
June	1st to 10th	Day	57% 4 9% 20% 8% 2	2927
	11th to 20th	Day	51% 4 13% 20% 11% 2	3000
	21st to end	Day	59% 4 12% 15% 10% 1	2934
July	1st to 10th	Day	56% 3 15% 21% 5%	6290
	11th to 20th	Day	51% 3 20% 22% 4	6285
	21st to end	Day	43% 4 19% 28% 7%	6728
August	1st to 10th	Day	51% 5% 19% 21% 5%	4549
	11th to 20th	Day	53% 3 21% 18% 5%	4261
	21st to end	Day	51% 3 15% 17% 13%	4388
September	1st to 10th	Day	45% 4 16% 26% 9%	2400
	11th to 20th	Day	43% 2 16% 28% 10%	2259
	21st to end	Day	51% 3 12% 25% 8%	2200
October	1st to 10th	Day	55% 4 12% 23% 6%	3494
	11th to 20th	Day	61% 2 15% 20% 2	3016
	21st to end	Day	57% 3 17% 18% 4	3180
November	1st to 10th	Day	61% 3 10% 19% 6%	1851
	11th to 20th	Day	67% 2 8% 16% 6%	1832
	21st to end	Day	69% 4 10% 14% 3	1591
December	1st to 10th	Day	72% 1 9% 13% 4	2350
	11th to 20th	Day	67% 1 5% 19% 8%	2688
	21st to end	Day	65% 3 7% 14% 11% 1	3851
January	1st to 10th	Night	72% 1 9% 14% 5%	8234
	11th to 20th	Night	75% 1 7% 13% 4	8280
	21st to end	Night	61% 2 8% 15% 13%	9057
February	1st to 10th	Night	57% 3 8% 21% 10% 1	2908
	11th to 20th	Night	63% 2 9% 15% 10% 1	2512
	21st to end	Night	58% 3 7% 18% 12% 1	2076
March	1st to 10th	Night	68% 3 7% 11% 10% 2	5494
	11th to 20th	Night	62% 2 11% 16% 8% 1	5405
	21st to end	Night	59% 2 5% 22% 9% 2	5104
April	1st to 10th	Night	59% 3 7% 16% 13% 2	2100
	11th to 20th	Night	53% 3 8% 22% 12% 2	2010
	21st to end	Night	53% 2 9% 21% 13% 2	1890
May	1st to 10th	Night	59% 2 8% 20% 11% 1	3823
	11th to 20th	Night	52% 2 14% 22% 10% 1	3576
	21st to end	Night	55% 2 10% 17% 13% 2	3927
June	1st to 10th	Night	52% 3 12% 23% 9% 1	1467
	11th to 20th	Night	47% 5% 14% 20% 12% 3	1400
	21st to end	Night	55% 4 12% 17% 11%	1458
July	1st to 10th	Night	49% 4 22% 21% 4	3560
	11th to 20th	Night	49% 3 22% 23% 3	3552
	21st to end	Night	39% 3 22% 29% 7%	3809
August	1st to 10th	Night	48% 4 19% 22% 8%	2576
	11th to 20th	Night	51% 4 21% 18% 5% 1	2819
	21st to end	Night	49% 4 14% 23% 10%	3507
September	1st to 10th	Night	43% 3 15% 28% 10% 1	2000
	11th to 20th	Night	42% 3 18% 30% 7% 1	2140
	21st to end	Night	46% 3 12% 29% 10%	2200
October	1st to 10th	Night	52% 3 13% 24% 8%	3684
	11th to 20th	Night	53% 2 16% 26% 4	4123
	21st to end	Night	55% 3 16% 18% 8%	4610
November	1st to 10th	Night	59% 3 12% 18% 7% 1	2667
	11th to 20th	Night	59% 3 10% 19% 8%	2784
	21st to end	Night	67% 3 9% 15% 5%	3025
December	1st to 10th	Night	71% 1 12% 12% 3	5060
	11th to 20th	Night	70% 2 5% 17% 5%	5742
	21st to end	Night	67% 2 5% 15% 11% 1	7338

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% 18% 38% 11% 2	220
	11th to 20th	Day	29% 18% 33% 17% 3	220
	21st to end	Day	19% 19% 42% 14% 5% 1	242
February	1st to 10th	Day	28% 23% 38% 8% 2 1	237
	11th to 20th	Day	28% 24% 34% 12% 2	483
	21st to end	Day	28% 25% 30% 13% 4	446
March	1st to 10th	Day	31% 20% 31% 14% 4	540
	11th to 20th	Day	31% 21% 30% 14% 2 1	540
	21st to end	Day	30% 23% 27% 14% 5% 1	594
April	1st to 10th	Day	36% 16% 31% 12% 3 1	540
	11th to 20th	Day	36% 20% 28% 12% 3 2	532
	21st to end	Day	36% 20% 28% 11% 5% 1	540
May	1st to 10th	Day	35% 16% 31% 13% 5%	507
	11th to 20th	Day	27% 18% 30% 20% 4 1	527
	21st to end	Day	28% 22% 29% 17% 4	573
June	1st to 10th	Day	27% 16% 32% 18% 7%	657
	11th to 20th	Day	26% 14% 30% 21% 7% 1	730
	21st to end	Day	28% 12% 30% 20% 8% 1	664
July	1st to 10th	Day	23% 13% 35% 20% 8% 1	525
	11th to 20th	Day	21% 10% 38% 23% 7% 1	524
	21st to end	Day	20% 13% 34% 24% 8% 2	576
August	1st to 10th	Day	20% 9% 33% 27% 9% 2	526
	11th to 20th	Day	23% 8% 29% 26% 12% 3	519
	21st to end	Day	26% 12% 27% 21% 10% 4	583
September	1st to 10th	Day	22% 13% 33% 20% 10% 2	530
	11th to 20th	Day	21% 10% 26% 26% 12% 5%	530
	21st to end	Day	27% 15% 26% 17% 10% 5%	530
October	1st to 10th	Day	28% 17% 26% 18% 10% 2	530
	11th to 20th	Day	32% 17% 29% 14% 7% 1	456
	21st to end	Day	39% 15% 25% 17% 4	462
November	1st to 10th	Day	37% 16% 26% 16% 5%	425
	11th to 20th	Day	33% 18% 30% 15% 4 1	372
	21st to end	Day	38% 19% 29% 13% 1	220
December	1st to 10th	Day	31% 18% 32% 13% 5%	220
	11th to 20th	Day	35% 23% 29% 10% 2 1	220
	21st to end	Day	34% 21% 27% 12% 4 1	242
January	1st to 10th	Night	29% 16% 32% 19% 5%	840
	11th to 20th	Night	29% 19% 28% 18% 5%	840
	21st to end	Night	19% 17% 32% 25% 6% 1	924
February	1st to 10th	Night	19% 19% 34% 21% 6%	840
	11th to 20th	Night	25% 18% 35% 18% 4	823
	21st to end	Night	25% 16% 32% 21% 6% 1	692
March	1st to 10th	Night	26% 17% 33% 20% 4	840
	11th to 20th	Night	28% 18% 31% 18% 4 1	840
	21st to end	Night	26% 19% 28% 21% 6% 1	924
April	1st to 10th	Night	33% 12% 30% 19% 5%	840
	11th to 20th	Night	29% 15% 27% 24% 5% 1	766
	21st to end	Night	31% 18% 28% 17% 5%	630
May	1st to 10th	Night	29% 15% 27% 21% 7%	500
	11th to 20th	Night	25% 10% 27% 28% 9%	394
	21st to end	Night	27% 9% 32% 23% 8%	433
June	1st to 10th	Night	25% 8% 27% 33% 8%	400
	11th to 20th	Night	24% 8% 24% 35% 10% 1	400
	21st to end	Night	26% 5% 23% 34% 12% 1	400
July	1st to 10th	Night	19% 6% 26% 35% 13%	390
	11th to 20th	Night	18% 3 22% 40% 16% 1	388
	21st to end	Night	17% 5% 23% 38% 16% 1	438
August	1st to 10th	Night	18% 4 18% 43% 18%	398
	11th to 20th	Night	19% 5% 22% 35% 18% 1	537
	21st to end	Night	22% 10% 19% 31% 15% 2	827
September	1st to 10th	Night	22% 7% 28% 32% 10% 1	800
	11th to 20th	Night	21% 7% 23% 28% 19% 2	800
	21st to end	Night	24% 10% 26% 25% 14% 2	800
October	1st to 10th	Night	25% 12% 25% 27% 10% 1	800
	11th to 20th	Night	31% 11% 26% 24% 8% 1	800
	21st to end	Night	34% 13% 26% 22% 5%	880
November	1st to 10th	Night	31% 13% 27% 21% 6% 1	820
	11th to 20th	Night	30% 15% 29% 17% 8% 2	840
	21st to end	Night	34% 18% 22% 21% 5%	885
December	1st to 10th	Night	32% 16% 25% 22% 5%	950
	11th to 20th	Night	30% 19% 26% 20% 5% 1	950
	21st to end	Night	34% 17% 30% 15% 4 1	968

Page generated at 2026-04-29 02:21:43. Version ac07

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