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 2025-01-07.

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% 5% 5% 5% 4 5% 6% 28%	104642
	Night	19% 12% 4 9% 5% 4 4 3 5% 6% 29%	104371
Transparency	Day	57% 3 12% 19% 8% 1	108103
	Night	58% 3 12% 19% 8% 1	109000
Seeing	Day	28% 16% 30% 17% 6% 1	15114
	Night	27% 13% 27% 24% 8% 1	23890

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% 18% 6% 14% 8% 5% 5% 4 5% 5% 17%	2565
	11th to 20th	Day	12% 15% 7% 17% 9% 4 4 2 3 4 23%	2520
	21st to end	Day	15% 11% 6% 10% 5% 7% 4 4 5% 8% 24%	2772
February	1st to 10th	Day	11% 18% 5% 12% 9% 6% 6% 3 3 5% 22%	1546
	11th to 20th	Day	11% 18% 7% 11% 6% 6% 4 3 5% 6% 22%	1799
	21st to end	Day	14% 17% 5% 12% 5% 5% 5% 3 4 4 25%	1570
March	1st to 10th	Day	20% 15% 4 9% 5% 4 4 3 4 4 27%	3116
	11th to 20th	Day	15% 19% 6% 12% 5% 5% 4 3 4 4 24%	3256
	21st to end	Day	14% 15% 4 9% 5% 4 4 3 4 5% 34%	4134
April	1st to 10th	Day	22% 15% 3 9% 5% 4 3 3 4 4 27%	2280
	11th to 20th	Day	22% 11% 3 6% 4 4 4 3 3 5% 34%	2312
	21st to end	Day	22% 12% 3 7% 5% 5% 4 3 4 5% 30%	2470
May	1st to 10th	Day	23% 9% 3 6% 5% 4 4 3 5% 5% 32%	4298
	11th to 20th	Day	18% 7% 3 7% 5% 4 5% 4 6% 8% 33%	4398
	21st to end	Day	19% 8% 3 8% 5% 6% 5% 4 6% 7% 30%	4837
June	1st to 10th	Day	24% 8% 3 8% 5% 4 5% 5% 6% 6% 25%	2780
	11th to 20th	Day	21% 7% 3 6% 4 5% 5% 4 6% 7% 32%	2850
	21st to end	Day	26% 9% 3 7% 5% 5% 5% 3 6% 6% 26%	2788
July	1st to 10th	Day	17% 8% 3 8% 6% 6% 6% 4 6% 7% 29%	4440
	11th to 20th	Day	20% 7% 3 8% 5% 5% 5% 5% 7% 8% 27%	4440
	21st to end	Day	15% 6% 2 6% 5% 5% 5% 4 6% 8% 37%	4814
August	1st to 10th	Day	17% 7% 3 8% 6% 6% 6% 5% 7% 9% 27%	4423
	11th to 20th	Day	22% 7% 3 6% 4 5% 5% 5% 7% 8% 27%	4089
	21st to end	Day	21% 7% 3 6% 5% 4 5% 4 6% 7% 32%	4254
September	1st to 10th	Day	19% 6% 2 6% 4 4 5% 4 6% 7% 37%	2280
	11th to 20th	Day	18% 6% 2 5% 4 4 4 3 6% 6% 41%	2146
	21st to end	Day	25% 8% 2 5% 3 4 3 4 5% 6% 34%	2090
October	1st to 10th	Day	26% 7% 3 7% 4 4 5% 3 5% 6% 30%	2036
	11th to 20th	Day	27% 11% 3 8% 6% 5% 4 3 4 6% 22%	1772
	21st to end	Day	29% 14% 3 7% 5% 3 5% 2 4 6% 22%	1881
November	1st to 10th	Day	22% 14% 3 7% 6% 5% 3 2 4 5% 29%	1761
	11th to 20th	Day	21% 16% 6% 9% 6% 4 4 2 3 5% 23%	1745
	21st to end	Day	21% 21% 4 10% 5% 4 3 4 5% 6% 18%	1515
December	1st to 10th	Day	20% 18% 6% 9% 8% 5% 5% 3 4 4 18%	2280
	11th to 20th	Day	21% 15% 7% 9% 7% 4 3 2 4 5% 24%	2618
	21st to end	Day	19% 18% 5% 8% 5% 4 5% 4 4 5% 23%	3767
January	1st to 10th	Night	15% 19% 7% 12% 6% 4 4 3 5% 5% 19%	4514
	11th to 20th	Night	13% 16% 6% 12% 7% 5% 5% 3 5% 6% 22%	4440
	21st to end	Night	11% 15% 5% 11% 7% 7% 5% 4 6% 6% 22%	4884
February	1st to 10th	Night	12% 14% 5% 11% 7% 5% 5% 3 5% 6% 27%	2632
	11th to 20th	Night	13% 16% 5% 12% 7% 5% 5% 3 5% 5% 24%	2266
	21st to end	Night	14% 16% 6% 8% 6% 4 4 3 5% 6% 28%	1884
March	1st to 10th	Night	22% 14% 4 8% 6% 3 6% 3 4 5% 25%	3724
	11th to 20th	Night	17% 17% 5% 11% 5% 5% 4 3 4 5% 24%	3689
	21st to end	Night	14% 14% 5% 8% 4 5% 5% 4 4 5% 31%	3483
April	1st to 10th	Night	22% 14% 3 8% 4 4 4 3 4 5% 27%	1900
	11th to 20th	Night	22% 9% 2 6% 5% 4 3 3 5% 6% 34%	1816
	21st to end	Night	22% 11% 2 7% 4 3 4 2 5% 5% 34%	1710
May	1st to 10th	Night	22% 9% 3 7% 5% 4 4 3 4 5% 33%	2657
	11th to 20th	Night	20% 7% 2 6% 4 3 4 4 5% 8% 38%	2495
	21st to end	Night	21% 6% 2 6% 4 5% 5% 4 6% 8% 32%	2738
June	1st to 10th	Night	22% 8% 2 7% 4 5% 4 4 6% 7% 31%	1394
	11th to 20th	Night	20% 7% 2 6% 4 3 5% 4 5% 8% 35%	1330
	21st to end	Night	24% 9% 2 7% 5% 4 4 3 6% 6% 29%	1385
July	1st to 10th	Night	17% 6% 3 8% 6% 6% 5% 5% 7% 8% 31%	2520
	11th to 20th	Night	18% 7% 2 7% 5% 5% 5% 4 5% 8% 34%	2520
	21st to end	Night	13% 4 2 5% 5% 5% 5% 4 6% 7% 46%	2739
August	1st to 10th	Night	16% 8% 3 6% 5% 5% 5% 4 5% 7% 35%	2506
	11th to 20th	Night	20% 8% 3 6% 5% 4 5% 4 5% 7% 32%	2706
	21st to end	Night	18% 7% 3 7% 4 5% 4 4 5% 7% 34%	3399
September	1st to 10th	Night	19% 6% 2 6% 4 4 3 3 4 6% 43%	1900
	11th to 20th	Night	18% 6% 2 5% 3 4 4 3 5% 6% 43%	2033
	21st to end	Night	21% 6% 2 5% 4 4 4 2 4 6% 41%	2090
October	1st to 10th	Night	21% 10% 2 6% 3 4 3 3 5% 6% 37%	2142
	11th to 20th	Night	27% 9% 3 6% 4 4 4 2 5% 5% 31%	2408
	21st to end	Night	27% 11% 3 7% 4 4 4 3 4 7% 25%	2717
November	1st to 10th	Night	21% 13% 4 8% 5% 4 4 2 5% 6% 29%	2537
	11th to 20th	Night	21% 12% 4 8% 5% 4 4 3 4 6% 28%	2651
	21st to end	Night	23% 18% 4 9% 5% 4 4 3 5% 5% 22%	2881
December	1st to 10th	Night	16% 14% 8% 15% 9% 5% 5% 3 3 5% 17%	4910
	11th to 20th	Night	23% 15% 4 11% 8% 4 4 3 3 3 20%	5591
	21st to end	Night	21% 18% 5% 10% 5% 3 4 3 3 3 25%	7180

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% 2 9% 14% 4	2566
	11th to 20th	Day	67% 2 7% 18% 6% 1	2520
	21st to end	Day	60% 2 8% 20% 10% 1	2772
February	1st to 10th	Day	66% 3 7% 14% 8% 2	1546
	11th to 20th	Day	64% 2 9% 14% 10% 1	1808
	21st to end	Day	63% 3 6% 17% 8% 3	1570
March	1st to 10th	Day	63% 1 9% 15% 10% 2	3119
	11th to 20th	Day	66% 2 7% 16% 9%	3256
	21st to end	Day	55% 2 5% 20% 15% 4	4134
April	1st to 10th	Day	62% 3 9% 14% 10% 3	2280
	11th to 20th	Day	55% 2 8% 22% 11% 2	2312
	21st to end	Day	59% 2 8% 16% 13% 2	2470
May	1st to 10th	Day	55% 2 9% 17% 16% 2	4312
	11th to 20th	Day	50% 2 15% 23% 9% 1	4402
	21st to end	Day	54% 3 7% 19% 15% 1	4837
June	1st to 10th	Day	58% 4 9% 20% 7% 2	2780
	11th to 20th	Day	50% 4 13% 20% 11% 2	2850
	21st to end	Day	59% 4 12% 15% 10%	2788
July	1st to 10th	Day	54% 4 13% 23% 6%	4370
	11th to 20th	Day	54% 3 19% 19% 5%	4365
	21st to end	Day	46% 4 19% 25% 6%	4661
August	1st to 10th	Day	52% 5% 18% 21% 4	4409
	11th to 20th	Day	54% 3 21% 18% 4	4129
	21st to end	Day	51% 3 14% 17% 14%	4254
September	1st to 10th	Day	46% 4 15% 25% 9%	2280
	11th to 20th	Day	44% 2 16% 27% 10%	2146
	21st to end	Day	52% 3 12% 25% 8%	2090
October	1st to 10th	Day	56% 4 12% 22% 5%	3387
	11th to 20th	Day	61% 2 15% 20% 2	2923
	21st to end	Day	57% 3 17% 18% 4	3081
November	1st to 10th	Day	59% 3 10% 20% 7% 1	1761
	11th to 20th	Day	66% 2 9% 17% 6% 1	1745
	21st to end	Day	68% 4 11% 14% 3	1515
December	1st to 10th	Day	72% 1 9% 13% 4	2280
	11th to 20th	Day	66% 1 6% 19% 8%	2618
	21st to end	Day	65% 3 7% 14% 11% 1	3767
January	1st to 10th	Night	68% 1 10% 15% 5%	4514
	11th to 20th	Night	65% 2 9% 19% 5% 1	4440
	21st to end	Night	63% 2 10% 14% 10%	4884
February	1st to 10th	Night	58% 3 8% 20% 9% 1	2632
	11th to 20th	Night	63% 2 10% 15% 9% 1	2268
	21st to end	Night	58% 3 8% 18% 12% 1	1884
March	1st to 10th	Night	63% 3 10% 14% 8% 2	3734
	11th to 20th	Night	64% 2 7% 17% 9% 1	3690
	21st to end	Night	57% 2 7% 22% 10% 3	3483
April	1st to 10th	Night	59% 3 7% 16% 13% 2	1900
	11th to 20th	Night	52% 3 8% 23% 13% 2	1816
	21st to end	Night	53% 3 9% 20% 14% 2	1710
May	1st to 10th	Night	56% 2 9% 22% 10% 2	2663
	11th to 20th	Night	47% 2 15% 23% 12% 1	2496
	21st to end	Night	51% 3 10% 20% 15% 1	2739
June	1st to 10th	Night	52% 3 12% 23% 8% 1	1394
	11th to 20th	Night	47% 5% 13% 20% 12% 3	1330
	21st to end	Night	56% 4 12% 17% 11%	1385
July	1st to 10th	Night	50% 4 19% 21% 6%	2480
	11th to 20th	Night	49% 4 22% 20% 4	2472
	21st to end	Night	38% 4 25% 26% 7%	2651
August	1st to 10th	Night	49% 4 19% 21% 7%	2496
	11th to 20th	Night	52% 4 22% 17% 4	2732
	21st to end	Night	49% 4 14% 23% 10%	3399
September	1st to 10th	Night	44% 3 14% 27% 10% 1	1900
	11th to 20th	Night	42% 3 18% 30% 7% 1	2033
	21st to end	Night	46% 3 12% 29% 10%	2090
October	1st to 10th	Night	53% 3 13% 23% 8%	3571
	11th to 20th	Night	54% 2 16% 25% 4	3996
	21st to end	Night	55% 3 16% 18% 8%	4467
November	1st to 10th	Night	58% 3 12% 19% 7% 1	2537
	11th to 20th	Night	58% 3 10% 20% 8%	2651
	21st to end	Night	66% 3 10% 15% 6%	2881
December	1st to 10th	Night	72% 2 13% 11% 3	4910
	11th to 20th	Night	70% 2 5% 17% 5%	5592
	21st to end	Night	66% 2 5% 15% 11% 1	7180

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% 37% 11% 3	192
	11th to 20th	Day	29% 17% 35% 16% 3	180
	21st to end	Day	19% 18% 43% 14% 6% 1	198
February	1st to 10th	Day	30% 24% 36% 8% 1 1	193
	11th to 20th	Day	27% 26% 33% 12% 2	407
	21st to end	Day	29% 26% 27% 13% 4	382
March	1st to 10th	Day	28% 20% 32% 15% 4	460
	11th to 20th	Day	30% 21% 30% 15% 3 1	460
	21st to end	Day	28% 24% 27% 15% 6% 1	506
April	1st to 10th	Day	34% 17% 31% 13% 4 1	460
	11th to 20th	Day	33% 21% 28% 12% 4 2	452
	21st to end	Day	35% 20% 29% 11% 4 1	460
May	1st to 10th	Day	34% 17% 32% 13% 5%	463
	11th to 20th	Day	26% 18% 31% 20% 4 1	487
	21st to end	Day	27% 23% 30% 16% 4	529
June	1st to 10th	Day	26% 16% 32% 18% 7%	610
	11th to 20th	Day	25% 14% 30% 21% 8% 1	680
	21st to end	Day	28% 12% 30% 21% 8% 1	618
July	1st to 10th	Day	22% 13% 35% 20% 8% 1	485
	11th to 20th	Day	21% 10% 37% 24% 7% 1	484
	21st to end	Day	20% 11% 33% 26% 8% 2	532
August	1st to 10th	Day	21% 10% 33% 26% 9% 2	486
	11th to 20th	Day	24% 8% 28% 26% 12% 3	479
	21st to end	Day	25% 12% 27% 20% 11% 5%	539
September	1st to 10th	Day	23% 12% 32% 20% 10% 2	490
	11th to 20th	Day	21% 10% 27% 26% 12% 5%	490
	21st to end	Day	26% 16% 27% 17% 11% 5%	490
October	1st to 10th	Day	29% 16% 26% 17% 10% 2	490
	11th to 20th	Day	33% 17% 28% 13% 7% 1	423
	21st to end	Day	38% 15% 25% 17% 5%	429
November	1st to 10th	Day	36% 15% 26% 16% 6% 1	395
	11th to 20th	Day	32% 17% 31% 15% 4 1	345
	21st to end	Day	39% 18% 29% 14% 1	200
December	1st to 10th	Day	33% 17% 32% 14% 6%	200
	11th to 20th	Day	37% 23% 28% 10% 2 1	200
	21st to end	Day	36% 21% 25% 13% 4 1	220
January	1st to 10th	Night	29% 16% 32% 18% 4 1	785
	11th to 20th	Night	28% 19% 29% 18% 5%	760
	21st to end	Night	19% 17% 33% 25% 6% 1	836
February	1st to 10th	Night	20% 19% 34% 21% 6%	760
	11th to 20th	Night	24% 17% 36% 18% 4	743
	21st to end	Night	25% 18% 31% 20% 6% 1	628
March	1st to 10th	Night	24% 17% 33% 21% 4	760
	11th to 20th	Night	28% 17% 31% 19% 5% 1	760
	21st to end	Night	25% 19% 27% 21% 6% 1	836
April	1st to 10th	Night	32% 12% 30% 19% 6% 1	760
	11th to 20th	Night	29% 15% 26% 24% 5% 1	692
	21st to end	Night	30% 19% 28% 18% 5%	570
May	1st to 10th	Night	28% 15% 28% 21% 8%	471
	11th to 20th	Night	25% 10% 26% 29% 9%	374
	21st to end	Night	27% 10% 33% 22% 8%	411
June	1st to 10th	Night	25% 8% 27% 32% 9%	380
	11th to 20th	Night	24% 7% 23% 35% 10% 1	380
	21st to end	Night	26% 5% 22% 34% 12% 1	380
July	1st to 10th	Night	19% 6% 27% 35% 13%	370
	11th to 20th	Night	18% 2 21% 41% 17% 1	368
	21st to end	Night	18% 4 22% 38% 17% 1	416
August	1st to 10th	Night	18% 4 17% 44% 17%	378
	11th to 20th	Night	20% 5% 21% 35% 18% 1	510
	21st to end	Night	22% 10% 20% 31% 16% 2	785
September	1st to 10th	Night	22% 7% 28% 31% 10% 1	760
	11th to 20th	Night	23% 7% 23% 28% 18% 2	760
	21st to end	Night	24% 10% 26% 24% 15% 1	760
October	1st to 10th	Night	26% 12% 24% 27% 10% 1	760
	11th to 20th	Night	32% 11% 25% 23% 8% 1	760
	21st to end	Night	34% 13% 26% 22% 5%	836
November	1st to 10th	Night	31% 13% 27% 22% 6% 1	780
	11th to 20th	Night	30% 15% 29% 17% 7% 2	800
	21st to end	Night	34% 18% 22% 21% 5%	841
December	1st to 10th	Night	32% 16% 24% 22% 5%	900
	11th to 20th	Night	31% 18% 26% 20% 5% 1	900
	21st to end	Night	34% 17% 30% 15% 4 1	920

Page generated at 2025-01-04 03:24:02. Version ac07

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