St-Pierre de la rivière du sud, portail étoilé de la côte du sud
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the St-Pierre de la rivière du sud, portail étoilé de la côte du sud clear sky chart from 2005-11-06 to 2024-02-25.

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% 3 4 4 5% 6% 30%	77998
	Night	18% 13% 5% 8% 6% 3 4 4 4 5% 28%	81299
Transparency	Day	55% 6% 13% 18% 8% 1	77701
	Night	58% 6% 11% 17% 8% 1	81131
Seeing	Day	26% 16% 30% 20% 7% 1	14405
	Night	25% 15% 31% 22% 6% 1	22981

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	13% 18% 7% 14% 9% 4 5% 4 4 5% 17%	2493
	11th to 20th	Day	12% 13% 7% 15% 10% 4 5% 3 3 4 23%	2520
	21st to end	Day	9% 10% 8% 12% 8% 4 4 4 5% 6% 29%	2772
February	1st to 10th	Day	12% 15% 6% 10% 9% 4 5% 4 5% 5% 24%	1553
	11th to 20th	Day	14% 16% 7% 11% 7% 4 4 3 4 5% 25%	1797
	21st to end	Day	13% 15% 6% 10% 7% 3 5% 3 4 5% 29%	1520
March	1st to 10th	Day	15% 13% 6% 9% 7% 4 4 3 4 6% 28%	1797
	11th to 20th	Day	18% 12% 6% 7% 7% 4 4 4 4 5% 29%	1913
	21st to end	Day	16% 12% 5% 8% 5% 4 5% 4 5% 5% 31%	2272
April	1st to 10th	Day	25% 12% 4 7% 6% 2 4 3 4 6% 26%	2160
	11th to 20th	Day	21% 11% 3 5% 5% 2 3 4 3 5% 38%	2248
	21st to end	Day	24% 11% 4 6% 5% 3 3 4 4 5% 30%	2340
May	1st to 10th	Day	23% 9% 4 5% 5% 3 4 4 3 7% 33%	2353
	11th to 20th	Day	21% 8% 3 6% 5% 3 5% 4 4 7% 34%	2478
	21st to end	Day	21% 8% 3 6% 6% 3 5% 4 5% 8% 31%	2824
June	1st to 10th	Day	22% 7% 3 6% 6% 4 5% 6% 7% 9% 26%	2700
	11th to 20th	Day	21% 6% 3 5% 5% 3 5% 5% 5% 7% 34%	2700
	21st to end	Day	23% 9% 4 7% 6% 3 5% 6% 5% 7% 26%	2700
July	1st to 10th	Day	17% 7% 3 6% 6% 3 5% 6% 6% 9% 32%	2638
	11th to 20th	Day	16% 7% 3 7% 6% 3 5% 5% 6% 9% 32%	2520
	21st to end	Day	18% 8% 2 6% 6% 4 5% 5% 6% 8% 32%	2744
August	1st to 10th	Day	19% 7% 3 7% 6% 5% 6% 6% 6% 10% 27%	2463
	11th to 20th	Day	16% 7% 3 6% 6% 4 4 4 6% 8% 36%	2304
	21st to end	Day	18% 7% 2 5% 6% 4 5% 5% 5% 7% 37%	2510
September	1st to 10th	Day	20% 6% 3 6% 5% 3 3 4 5% 8% 38%	2155
	11th to 20th	Day	21% 5% 2 5% 4 2 3 3 4 5% 45%	1980
	21st to end	Day	23% 7% 2 5% 3 3 3 3 5% 6% 39%	1980
October	1st to 10th	Day	21% 9% 3 6% 5% 2 4 4 5% 6% 35%	1979
	11th to 20th	Day	25% 12% 4 7% 6% 4 4 5% 4 5% 24%	1655
	21st to end	Day	30% 13% 3 6% 5% 3 4 3 4 6% 23%	1782
November	1st to 10th	Day	19% 13% 5% 8% 6% 3 4 4 5% 4 29%	1671
	11th to 20th	Day	21% 15% 5% 9% 6% 3 4 3 4 5% 24%	1677
	21st to end	Day	21% 18% 7% 9% 6% 3 3 4 3 4 23%	1371
December	1st to 10th	Day	23% 18% 6% 10% 5% 3 5% 4 4 4 18%	1330
	11th to 20th	Day	20% 16% 5% 9% 6% 4 3 3 3 3 26%	1668
	21st to end	Day	23% 14% 6% 10% 6% 3 4 3 3 6% 23%	2431
January	1st to 10th	Night	14% 20% 8% 11% 10% 4 4 3 3 3 20%	4451
	11th to 20th	Night	12% 16% 7% 13% 9% 4 5% 4 4 4 21%	4440
	21st to end	Night	10% 13% 7% 11% 9% 4 6% 5% 5% 5% 25%	4884
February	1st to 10th	Night	12% 14% 6% 11% 8% 4 5% 5% 5% 5% 25%	2625
	11th to 20th	Night	13% 16% 7% 11% 7% 4 6% 4 4 4 24%	2266
	21st to end	Night	14% 16% 5% 9% 7% 4 4 4 3 5% 29%	1831
March	1st to 10th	Night	16% 15% 5% 8% 6% 3 5% 3 4 6% 29%	2150
	11th to 20th	Night	18% 13% 4 8% 6% 3 5% 4 4 5% 29%	2045
	21st to end	Night	19% 12% 5% 8% 6% 3 4 3 4 5% 31%	2081
April	1st to 10th	Night	24% 16% 5% 7% 4 3 3 3 4 5% 26%	1800
	11th to 20th	Night	22% 10% 3 5% 5% 2 4 5% 6% 6% 32%	1660
	21st to end	Night	24% 13% 4 6% 5% 2 4 4 3 4 32%	1620
May	1st to 10th	Night	26% 10% 3 6% 5% 3 3 3 5% 5% 31%	1620
	11th to 20th	Night	22% 5% 4 6% 7% 3 4 5% 4 5% 36%	1417
	21st to end	Night	21% 7% 3 5% 6% 3 4 5% 5% 4 36%	1448
June	1st to 10th	Night	23% 8% 3 5% 8% 5% 6% 5% 7% 6% 25%	1260
	11th to 20th	Night	18% 7% 3 5% 6% 2 4 5% 5% 7% 37%	1260
	21st to end	Night	22% 10% 3 5% 5% 4 5% 4 5% 7% 31%	1260
July	1st to 10th	Night	17% 7% 3 7% 5% 3 4 4 5% 9% 34%	1318
	11th to 20th	Night	17% 7% 3 6% 5% 4 5% 5% 7% 9% 33%	1440
	21st to end	Night	15% 7% 2 6% 7% 4 6% 5% 6% 7% 33%	1574
August	1st to 10th	Night	16% 6% 2 4 5% 2 5% 5% 6% 9% 38%	1456
	11th to 20th	Night	18% 8% 3 6% 5% 4 5% 4 7% 8% 32%	1596
	21st to end	Night	17% 6% 2 5% 5% 3 5% 5% 5% 7% 38%	1844
September	1st to 10th	Night	19% 7% 2 6% 6% 3 4 4 5% 6% 38%	1804
	11th to 20th	Night	19% 8% 3 5% 4 2 3 3 4 6% 41%	1980
	21st to end	Night	22% 7% 3 5% 4 3 3 4 4 5% 40%	1980
October	1st to 10th	Night	21% 9% 3 6% 4 2 4 4 5% 5% 37%	1980
	11th to 20th	Night	26% 12% 4 6% 5% 3 3 3 4 5% 29%	2304
	21st to end	Night	26% 13% 4 5% 5% 3 4 4 4 7% 26%	2574
November	1st to 10th	Night	20% 14% 5% 7% 6% 3 4 4 4 5% 27%	2407
	11th to 20th	Night	19% 12% 5% 9% 7% 3 5% 3 4 5% 28%	2500
	21st to end	Night	20% 17% 7% 9% 5% 3 4 4 3 4 23%	2807
December	1st to 10th	Night	22% 18% 6% 10% 7% 3 4 3 4 4 18%	2850
	11th to 20th	Night	18% 17% 7% 9% 7% 4 3 4 3 5% 22%	3531
	21st to end	Night	22% 20% 6% 8% 5% 2 3 2 3 3 26%	5236

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	66% 7% 12% 12% 3	2494
	11th to 20th	Day	63% 4 11% 16% 6% 1	2520
	21st to end	Day	55% 8% 10% 19% 8%	2772
February	1st to 10th	Day	62% 4 11% 14% 7% 1	1553
	11th to 20th	Day	63% 4 10% 15% 8% 1	1806
	21st to end	Day	59% 4 8% 19% 8% 2	1520
March	1st to 10th	Day	58% 5% 9% 16% 11% 1	1800
	11th to 20th	Day	58% 5% 9% 17% 11% 1	1913
	21st to end	Day	55% 5% 12% 17% 9% 2	2272
April	1st to 10th	Day	61% 3 11% 13% 9% 2	2160
	11th to 20th	Day	50% 4 10% 22% 12% 2	2248
	21st to end	Day	56% 4 10% 16% 11% 3	2340
May	1st to 10th	Day	52% 5% 12% 16% 13% 2	2353
	11th to 20th	Day	51% 5% 13% 20% 10% 1	2482
	21st to end	Day	52% 7% 11% 19% 10%	2824
June	1st to 10th	Day	52% 9% 13% 18% 7% 1	2700
	11th to 20th	Day	49% 7% 13% 20% 10% 1	2700
	21st to end	Day	57% 7% 11% 16% 8%	2700
July	1st to 10th	Day	47% 8% 18% 20% 6%	2566
	11th to 20th	Day	47% 7% 18% 22% 7%	2445
	21st to end	Day	50% 8% 16% 19% 7%	2591
August	1st to 10th	Day	52% 9% 19% 18% 2	2449
	11th to 20th	Day	45% 8% 20% 20% 8%	2304
	21st to end	Day	46% 7% 16% 23% 8%	2510
September	1st to 10th	Day	45% 5% 16% 22% 11% 1	2155
	11th to 20th	Day	42% 4 16% 27% 11%	1980
	21st to end	Day	46% 4 14% 25% 10%	1980
October	1st to 10th	Day	50% 4 12% 25% 8%	1979
	11th to 20th	Day	62% 6% 15% 15% 2	1655
	21st to end	Day	63% 5% 11% 16% 4 1	1782
November	1st to 10th	Day	57% 6% 13% 17% 6%	1671
	11th to 20th	Day	62% 5% 12% 15% 5%	1677
	21st to end	Day	66% 5% 12% 13% 4	1371
December	1st to 10th	Day	69% 6% 9% 12% 4	1330
	11th to 20th	Day	64% 3 9% 18% 6%	1668
	21st to end	Day	65% 6% 11% 12% 5% 2	2431
January	1st to 10th	Night	69% 6% 9% 11% 5%	4451
	11th to 20th	Night	65% 4 11% 15% 5%	4440
	21st to end	Night	59% 6% 11% 14% 9% 1	4884
February	1st to 10th	Night	60% 5% 10% 15% 9% 1	2625
	11th to 20th	Night	63% 4 8% 15% 9% 1	2268
	21st to end	Night	59% 4 7% 17% 12% 1	1831
March	1st to 10th	Night	58% 5% 8% 17% 10% 1	2160
	11th to 20th	Night	57% 6% 9% 16% 10% 2	2046
	21st to end	Night	57% 4 10% 17% 10% 3	2081
April	1st to 10th	Night	62% 3 8% 13% 12% 3	1800
	11th to 20th	Night	50% 5% 10% 21% 12% 2	1660
	21st to end	Night	57% 4 7% 16% 13% 2	1620
May	1st to 10th	Night	56% 3 10% 16% 13% 2	1620
	11th to 20th	Night	50% 6% 11% 19% 14% 1	1418
	21st to end	Night	50% 6% 11% 17% 14% 1	1449
June	1st to 10th	Night	56% 8% 12% 17% 6%	1260
	11th to 20th	Night	46% 8% 10% 24% 10% 3	1260
	21st to end	Night	54% 7% 14% 16% 10%	1260
July	1st to 10th	Night	46% 8% 18% 20% 8%	1280
	11th to 20th	Night	46% 7% 18% 22% 6% 1	1392
	21st to end	Night	48% 10% 15% 20% 7%	1486
August	1st to 10th	Night	41% 9% 20% 27% 3	1446
	11th to 20th	Night	49% 8% 19% 18% 7%	1596
	21st to end	Night	43% 8% 14% 27% 8%	1844
September	1st to 10th	Night	47% 6% 13% 22% 10% 1	1804
	11th to 20th	Night	45% 6% 16% 24% 9%	1980
	21st to end	Night	46% 6% 11% 25% 11%	1980
October	1st to 10th	Night	49% 5% 11% 25% 10% 1	1980
	11th to 20th	Night	58% 6% 12% 19% 5%	2304
	21st to end	Night	59% 5% 13% 15% 7%	2574
November	1st to 10th	Night	59% 5% 12% 18% 5%	2407
	11th to 20th	Night	58% 6% 11% 16% 8%	2500
	21st to end	Night	65% 5% 11% 14% 5%	2807
December	1st to 10th	Night	69% 5% 10% 12% 3	2850
	11th to 20th	Night	65% 4 7% 17% 6%	3532
	21st to end	Night	65% 4 10% 14% 7% 1	5236

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	27% 27% 31% 13% 2 1	180
	11th to 20th	Day	32% 24% 32% 9% 3	180
	21st to end	Day	16% 28% 35% 16% 4 1	198
February	1st to 10th	Day	29% 27% 31% 11% 2	213
	11th to 20th	Day	23% 30% 33% 12% 2	432
	21st to end	Day	27% 23% 30% 18% 3	362
March	1st to 10th	Day	28% 21% 28% 18% 4 1	420
	11th to 20th	Day	26% 20% 30% 18% 5% 1	420
	21st to end	Day	23% 22% 28% 18% 7% 2	462
April	1st to 10th	Day	33% 20% 26% 15% 6%	420
	11th to 20th	Day	30% 20% 25% 20% 5% 1	412
	21st to end	Day	28% 20% 31% 15% 5% 2	420
May	1st to 10th	Day	30% 14% 35% 14% 5% 1	423
	11th to 20th	Day	23% 13% 31% 24% 8% 1	447
	21st to end	Day	23% 16% 37% 17% 7%	584
June	1st to 10th	Day	25% 15% 31% 22% 7%	630
	11th to 20th	Day	23% 13% 30% 25% 9%	630
	21st to end	Day	26% 10% 30% 24% 10% 1	630
July	1st to 10th	Day	20% 11% 33% 26% 9% 1	561
	11th to 20th	Day	18% 13% 36% 25% 7% 1	444
	21st to end	Day	20% 8% 37% 25% 8% 1	488
August	1st to 10th	Day	20% 10% 32% 25% 11% 2	446
	11th to 20th	Day	18% 10% 29% 28% 13% 1	439
	21st to end	Day	22% 14% 23% 24% 14% 4	495
September	1st to 10th	Day	23% 12% 28% 24% 10% 3	450
	11th to 20th	Day	24% 11% 32% 21% 10% 2	450
	21st to end	Day	23% 14% 30% 20% 8% 5%	450
October	1st to 10th	Day	24% 16% 30% 20% 8% 2	449
	11th to 20th	Day	32% 13% 28% 18% 8% 1	360
	21st to end	Day	36% 18% 29% 13% 3	396
November	1st to 10th	Day	31% 18% 34% 15% 2 1	365
	11th to 20th	Day	29% 21% 26% 16% 7% 1	370
	21st to end	Day	32% 21% 34% 12%	221
December	1st to 10th	Day	33% 16% 27% 19% 3 1	180
	11th to 20th	Day	34% 26% 24% 12% 2 1	180
	21st to end	Day	39% 21% 27% 13% 1	198
January	1st to 10th	Night	27% 21% 34% 15% 2	764
	11th to 20th	Night	25% 22% 33% 17% 3	760
	21st to end	Night	17% 21% 36% 21% 5%	836
February	1st to 10th	Night	18% 23% 35% 18% 5%	760
	11th to 20th	Night	24% 22% 37% 12% 4	743
	21st to end	Night	25% 18% 32% 21% 4	611
March	1st to 10th	Night	23% 15% 39% 19% 4	720
	11th to 20th	Night	23% 16% 36% 18% 5% 1	720
	21st to end	Night	23% 14% 33% 23% 7% 1	792
April	1st to 10th	Night	32% 16% 26% 22% 5%	720
	11th to 20th	Night	27% 12% 33% 22% 6% 1	596
	21st to end	Night	31% 12% 26% 23% 7%	540
May	1st to 10th	Night	29% 9% 29% 25% 8%	540
	11th to 20th	Night	26% 7% 29% 30% 8% 1	356
	21st to end	Night	26% 9% 32% 25% 7%	389
June	1st to 10th	Night	27% 6% 29% 32% 6%	360
	11th to 20th	Night	20% 6% 26% 37% 11%	360
	21st to end	Night	23% 11% 28% 29% 8%	360
July	1st to 10th	Night	20% 6% 35% 29% 10%	350
	11th to 20th	Night	18% 5% 31% 34% 11% 1	348
	21st to end	Night	17% 7% 30% 36% 11%	394
August	1st to 10th	Night	17% 4 29% 36% 14% 1	382
	11th to 20th	Night	20% 6% 27% 33% 13% 1	532
	21st to end	Night	20% 8% 29% 30% 12% 2	656
September	1st to 10th	Night	23% 7% 29% 29% 10% 1	720
	11th to 20th	Night	23% 9% 31% 26% 11% 1	720
	21st to end	Night	23% 11% 28% 27% 11%	720
October	1st to 10th	Night	25% 12% 31% 25% 6% 1	720
	11th to 20th	Night	31% 16% 25% 21% 7% 1	720
	21st to end	Night	33% 14% 30% 18% 5%	792
November	1st to 10th	Night	30% 17% 28% 21% 4	740
	11th to 20th	Night	27% 20% 27% 19% 7% 1	775
	21st to end	Night	29% 18% 32% 16% 4 1	850
December	1st to 10th	Night	32% 18% 30% 16% 5%	850
	11th to 20th	Night	28% 22% 29% 14% 6%	850
	21st to end	Night	33% 21% 27% 16% 3	935

Page generated at 2024-02-22 06:05:48. Version ac07

Copyright 2024 Attilla Danko