La Seigneurie du Triton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the La Seigneurie du Triton clear sky chart from 2005-11-06 to 2024-03-06.

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	20% 13% 5% 9% 7% 4 5% 4 5% 6% 23%	78108
	Night	18% 14% 6% 9% 8% 4 5% 4 4 5% 23%	81407
Transparency	Day	62% 7% 10% 14% 7% 1	77813
	Night	63% 7% 10% 14% 6% 1	81237
Seeing	Day	28% 18% 30% 17% 6% 2	14100
	Night	27% 14% 30% 22% 7% 1	22858

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% 19% 9% 17% 11% 4 4 5% 4 3 11%	2517
	11th to 20th	Day	13% 13% 7% 16% 14% 7% 5% 4 4 4 13%	2520
	21st to end	Day	9% 15% 9% 13% 8% 4 7% 5% 4 6% 19%	2772
February	1st to 10th	Day	9% 14% 7% 14% 13% 7% 8% 5% 4 4 16%	1530
	11th to 20th	Day	13% 18% 7% 14% 8% 5% 6% 5% 5% 5% 15%	1782
	21st to end	Day	13% 15% 7% 12% 8% 4 7% 5% 4 5% 20%	1570
March	1st to 10th	Day	13% 15% 7% 12% 10% 3 5% 4 3 4 24%	1847
	11th to 20th	Day	17% 15% 7% 10% 6% 4 6% 4 4 4 23%	1852
	21st to end	Day	17% 15% 6% 9% 7% 3 4 4 4 4 27%	2361
April	1st to 10th	Day	24% 15% 6% 9% 6% 3 4 3 3 5% 22%	2160
	11th to 20th	Day	21% 12% 4 7% 5% 3 4 3 4 6% 31%	2195
	21st to end	Day	22% 13% 3 9% 5% 3 4 3 4 6% 28%	2340
May	1st to 10th	Day	23% 11% 4 7% 5% 3 4 4 5% 6% 30%	2474
	11th to 20th	Day	19% 9% 4 6% 6% 3 5% 4 5% 7% 33%	2478
	21st to end	Day	23% 8% 3 6% 6% 4 4 4 5% 6% 29%	2733
June	1st to 10th	Day	23% 10% 3 6% 7% 4 5% 4 5% 7% 25%	2700
	11th to 20th	Day	22% 8% 3 5% 6% 4 5% 5% 5% 8% 29%	2700
	21st to end	Day	25% 8% 4 7% 7% 4 5% 4 5% 6% 25%	2700
July	1st to 10th	Day	21% 8% 3 7% 7% 3 5% 5% 7% 8% 26%	2545
	11th to 20th	Day	18% 8% 4 8% 8% 4 6% 5% 6% 8% 25%	2520
	21st to end	Day	19% 8% 3 7% 7% 4 6% 6% 6% 7% 26%	2744
August	1st to 10th	Day	22% 9% 4 9% 7% 4 5% 6% 6% 8% 20%	2506
	11th to 20th	Day	21% 9% 3 6% 6% 3 5% 6% 6% 8% 25%	2354
	21st to end	Day	21% 8% 4 7% 7% 4 5% 6% 6% 7% 26%	2435
September	1st to 10th	Day	22% 8% 3 7% 4 3 5% 4 6% 6% 32%	2160
	11th to 20th	Day	21% 8% 3 6% 4 3 3 4 6% 7% 34%	2039
	21st to end	Day	27% 9% 3 5% 5% 3 4 4 5% 6% 30%	1980
October	1st to 10th	Day	26% 11% 4 7% 5% 2 4 4 4 5% 28%	1919
	11th to 20th	Day	27% 19% 5% 9% 5% 2 4 4 4 4 17%	1674
	21st to end	Day	30% 19% 4 8% 5% 2 3 3 3 4 20%	1782
November	1st to 10th	Day	23% 18% 6% 8% 5% 3 4 4 3 5% 21%	1671
	11th to 20th	Day	23% 21% 6% 11% 6% 3 3 3 3 4 17%	1630
	21st to end	Day	20% 22% 8% 13% 8% 3 3 3 3 5% 12%	1387
December	1st to 10th	Day	21% 20% 7% 13% 11% 4 4 3 3 3 11%	1330
	11th to 20th	Day	20% 19% 7% 13% 8% 3 4 4 3 4 16%	1668
	21st to end	Day	21% 20% 8% 9% 12% 4 4 4 4 5% 11%	2533
January	1st to 10th	Night	14% 20% 9% 13% 11% 7% 6% 5% 4 3 10%	4429
	11th to 20th	Night	12% 14% 6% 15% 16% 6% 6% 3 4 3 14%	4440
	21st to end	Night	9% 14% 8% 13% 10% 7% 7% 6% 5% 5% 17%	4884
February	1st to 10th	Night	10% 15% 7% 10% 11% 5% 7% 6% 4 5% 19%	2646
	11th to 20th	Night	11% 18% 7% 13% 9% 5% 6% 4 4 5% 16%	2284
	21st to end	Night	11% 17% 7% 10% 7% 4 6% 5% 4 6% 22%	1884
March	1st to 10th	Night	15% 13% 5% 12% 7% 4 6% 4 5% 6% 23%	2217
	11th to 20th	Night	17% 16% 5% 8% 8% 4 5% 4 4 5% 23%	2106
	21st to end	Night	14% 14% 5% 10% 7% 4 4 4 4 4 28%	1994
April	1st to 10th	Night	22% 17% 6% 9% 6% 3 4 4 4 5% 22%	1800
	11th to 20th	Night	22% 11% 3 6% 5% 3 4 5% 4 6% 30%	1712
	21st to end	Night	21% 12% 5% 7% 5% 3 4 3 4 5% 31%	1620
May	1st to 10th	Night	24% 9% 3 6% 5% 3 5% 4 4 5% 31%	1503
	11th to 20th	Night	19% 11% 3 5% 6% 3 4 5% 4 6% 34%	1415
	21st to end	Night	25% 7% 3 6% 5% 3 3 3 4 5% 36%	1537
June	1st to 10th	Night	21% 9% 5% 6% 6% 3 5% 5% 5% 7% 28%	1260
	11th to 20th	Night	19% 7% 3 5% 7% 2 4 5% 5% 8% 34%	1260
	21st to end	Night	22% 8% 4 7% 5% 4 4 4 6% 8% 29%	1260
July	1st to 10th	Night	19% 7% 4 7% 7% 4 4 5% 6% 8% 29%	1410
	11th to 20th	Night	16% 7% 3 6% 7% 3 5% 6% 7% 8% 32%	1440
	21st to end	Night	18% 8% 3 6% 5% 3 5% 6% 6% 8% 32%	1574
August	1st to 10th	Night	16% 9% 2 6% 5% 3 5% 5% 8% 8% 33%	1432
	11th to 20th	Night	19% 9% 3 7% 6% 3 4 4 6% 8% 30%	1528
	21st to end	Night	20% 8% 3 5% 5% 2 4 4 5% 7% 35%	1919
September	1st to 10th	Night	21% 7% 2 4 5% 3 3 4 5% 5% 39%	1800
	11th to 20th	Night	21% 9% 3 6% 5% 3 4 4 5% 6% 35%	1921
	21st to end	Night	21% 9% 3 6% 5% 3 4 4 4 5% 37%	1980
October	1st to 10th	Night	21% 11% 3 6% 5% 2 4 4 4 6% 34%	2038
	11th to 20th	Night	28% 14% 4 7% 5% 3 4 4 4 6% 22%	2286
	21st to end	Night	27% 18% 4 6% 6% 2 5% 3 4 4 20%	2574
November	1st to 10th	Night	21% 18% 6% 7% 6% 3 4 4 4 5% 21%	2407
	11th to 20th	Night	21% 16% 6% 10% 7% 3 5% 4 4 4 19%	2548
	21st to end	Night	22% 19% 7% 12% 9% 3 4 3 3 4 13%	2792
December	1st to 10th	Night	19% 19% 8% 14% 9% 4 4 4 3 4 12%	2850
	11th to 20th	Night	21% 15% 7% 13% 9% 4 5% 4 4 3 15%	3531
	21st to end	Night	20% 23% 8% 10% 9% 4 4 4 3 3 13%	5126

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	78% 5% 7% 8% 2	2518
	11th to 20th	Day	75% 4 7% 10% 4	2520
	21st to end	Day	65% 6% 6% 13% 9%	2772
February	1st to 10th	Day	71% 5% 6% 10% 6% 2	1530
	11th to 20th	Day	71% 5% 7% 9% 8% 1	1791
	21st to end	Day	66% 4 9% 14% 5% 2	1570
March	1st to 10th	Day	65% 5% 6% 13% 10% 2	1850
	11th to 20th	Day	66% 5% 6% 13% 9% 1	1852
	21st to end	Day	62% 4 7% 15% 10% 2	2361
April	1st to 10th	Day	67% 4 10% 10% 7% 3	2160
	11th to 20th	Day	55% 5% 8% 17% 12% 3	2195
	21st to end	Day	60% 5% 9% 13% 12% 2	2340
May	1st to 10th	Day	55% 6% 9% 15% 12% 3	2474
	11th to 20th	Day	51% 7% 10% 18% 12% 1	2482
	21st to end	Day	55% 8% 8% 16% 11% 1	2733
June	1st to 10th	Day	58% 8% 9% 16% 8% 2	2700
	11th to 20th	Day	52% 8% 12% 17% 9% 2	2700
	21st to end	Day	60% 8% 10% 13% 9%	2700
July	1st to 10th	Day	53% 9% 14% 18% 5%	2475
	11th to 20th	Day	55% 9% 13% 17% 5%	2445
	21st to end	Day	57% 10% 13% 15% 5%	2591
August	1st to 10th	Day	60% 11% 13% 13% 2	2492
	11th to 20th	Day	53% 11% 15% 15% 6%	2354
	21st to end	Day	55% 10% 12% 18% 5%	2435
September	1st to 10th	Day	51% 7% 14% 19% 7%	2160
	11th to 20th	Day	49% 7% 18% 18% 7%	2039
	21st to end	Day	55% 7% 14% 17% 7%	1980
October	1st to 10th	Day	59% 6% 11% 17% 8%	1919
	11th to 20th	Day	70% 7% 10% 11% 2	1674
	21st to end	Day	69% 5% 10% 12% 4	1782
November	1st to 10th	Day	67% 6% 9% 13% 4	1671
	11th to 20th	Day	73% 5% 8% 10% 3 1	1630
	21st to end	Day	77% 6% 8% 7% 1	1387
December	1st to 10th	Day	79% 5% 5% 9% 2	1330
	11th to 20th	Day	72% 4 7% 11% 5%	1668
	21st to end	Day	75% 6% 7% 8% 3	2533
January	1st to 10th	Night	77% 6% 8% 6% 2	4429
	11th to 20th	Night	76% 5% 7% 9% 3 1	4440
	21st to end	Night	66% 7% 9% 10% 8%	4884
February	1st to 10th	Night	65% 7% 8% 13% 7% 1	2646
	11th to 20th	Night	71% 5% 7% 10% 5% 1	2286
	21st to end	Night	65% 4 8% 14% 8% 1	1884
March	1st to 10th	Night	63% 6% 8% 15% 7% 1	2227
	11th to 20th	Night	63% 5% 9% 13% 9% 1	2107
	21st to end	Night	60% 5% 9% 16% 8% 2	1994
April	1st to 10th	Night	66% 5% 9% 10% 8% 2	1800
	11th to 20th	Night	54% 6% 9% 18% 11% 1	1712
	21st to end	Night	55% 6% 9% 18% 11% 1	1620
May	1st to 10th	Night	55% 7% 10% 14% 13% 2	1503
	11th to 20th	Night	51% 6% 12% 18% 13% 1	1416
	21st to end	Night	52% 6% 10% 19% 11% 2	1538
June	1st to 10th	Night	55% 9% 10% 18% 7% 2	1260
	11th to 20th	Night	48% 9% 13% 18% 10% 3	1260
	21st to end	Night	52% 9% 13% 15% 10%	1260
July	1st to 10th	Night	51% 9% 17% 17% 6%	1370
	11th to 20th	Night	46% 11% 16% 20% 6%	1392
	21st to end	Night	49% 11% 14% 20% 6%	1486
August	1st to 10th	Night	46% 13% 17% 21% 3	1422
	11th to 20th	Night	50% 11% 19% 16% 4	1528
	21st to end	Night	48% 10% 15% 23% 4	1919
September	1st to 10th	Night	47% 8% 13% 23% 9%	1800
	11th to 20th	Night	51% 7% 16% 21% 5%	1921
	21st to end	Night	50% 7% 13% 24% 6%	1980
October	1st to 10th	Night	52% 6% 14% 18% 9% 1	2038
	11th to 20th	Night	64% 8% 11% 13% 4	2286
	21st to end	Night	69% 6% 9% 11% 4 1	2574
November	1st to 10th	Night	65% 7% 11% 13% 4 1	2407
	11th to 20th	Night	69% 6% 9% 11% 5%	2548
	21st to end	Night	77% 6% 7% 8% 2	2792
December	1st to 10th	Night	78% 5% 8% 7% 2	2850
	11th to 20th	Night	74% 5% 6% 10% 5%	3532
	21st to end	Night	77% 5% 7% 9% 2	5126

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	26% 22% 41% 10% 2	180
	11th to 20th	Day	23% 19% 37% 14% 6%	180
	21st to end	Day	21% 17% 34% 20% 8% 1	198
February	1st to 10th	Day	21% 28% 41% 9% 1 1	185
	11th to 20th	Day	22% 30% 33% 13% 2	390
	21st to end	Day	25% 27% 32% 11% 4 1	382
March	1st to 10th	Day	24% 20% 34% 17% 5%	440
	11th to 20th	Day	28% 19% 31% 15% 6%	420
	21st to end	Day	26% 24% 29% 15% 5% 2	462
April	1st to 10th	Day	32% 22% 28% 12% 5% 1	420
	11th to 20th	Day	32% 20% 26% 12% 7% 2	412
	21st to end	Day	30% 21% 33% 12% 3 1	420
May	1st to 10th	Day	31% 21% 28% 13% 7%	423
	11th to 20th	Day	26% 19% 31% 18% 6% 1	447
	21st to end	Day	31% 20% 30% 14% 4 1	493
June	1st to 10th	Day	28% 16% 32% 17% 6% 1	630
	11th to 20th	Day	27% 17% 26% 20% 9% 1	630
	21st to end	Day	29% 11% 30% 21% 8% 1	630
July	1st to 10th	Day	21% 15% 32% 25% 6% 1	470
	11th to 20th	Day	20% 14% 33% 23% 7% 2	444
	21st to end	Day	25% 12% 28% 25% 10% 1	488
August	1st to 10th	Day	25% 11% 32% 22% 7% 3	446
	11th to 20th	Day	21% 8% 31% 27% 11% 3	439
	21st to end	Day	25% 17% 27% 15% 10% 6%	495
September	1st to 10th	Day	28% 14% 27% 18% 8% 5%	450
	11th to 20th	Day	23% 15% 29% 21% 9% 3	450
	21st to end	Day	26% 18% 26% 15% 12% 4	450
October	1st to 10th	Day	26% 18% 26% 20% 8% 3	450
	11th to 20th	Day	39% 17% 24% 10% 7% 2	387
	21st to end	Day	40% 16% 27% 13% 4 1	396
November	1st to 10th	Day	35% 22% 28% 12% 4	365
	11th to 20th	Day	32% 20% 30% 13% 3 1	290
	21st to end	Day	33% 22% 31% 12% 2 1	180
December	1st to 10th	Day	36% 14% 28% 19% 3	180
	11th to 20th	Day	28% 26% 35% 7% 3 1	180
	21st to end	Day	34% 19% 29% 11% 6% 1	198
January	1st to 10th	Night	26% 17% 34% 17% 5%	760
	11th to 20th	Night	25% 18% 32% 19% 5%	760
	21st to end	Night	15% 15% 35% 26% 7% 1	836
February	1st to 10th	Night	17% 20% 37% 21% 5%	760
	11th to 20th	Night	23% 17% 38% 16% 5%	743
	21st to end	Night	24% 17% 35% 20% 4	628
March	1st to 10th	Night	22% 17% 35% 22% 5%	743
	11th to 20th	Night	28% 18% 30% 18% 6% 1	720
	21st to end	Night	23% 18% 31% 20% 6% 1	792
April	1st to 10th	Night	32% 14% 28% 22% 4	720
	11th to 20th	Night	30% 15% 27% 21% 7% 1	648
	21st to end	Night	28% 19% 31% 18% 4	540
May	1st to 10th	Night	29% 13% 29% 24% 5%	423
	11th to 20th	Night	25% 10% 33% 25% 7%	354
	21st to end	Night	30% 12% 32% 21% 5% 1	389
June	1st to 10th	Night	25% 8% 35% 25% 5% 1	360
	11th to 20th	Night	23% 9% 29% 29% 10%	360
	21st to end	Night	23% 10% 29% 30% 8%	360
July	1st to 10th	Night	20% 8% 32% 30% 10% 1	350
	11th to 20th	Night	16% 10% 28% 31% 14% 1	348
	21st to end	Night	21% 6% 26% 35% 11% 1	394
August	1st to 10th	Night	19% 7% 26% 34% 13% 1	358
	11th to 20th	Night	21% 8% 27% 30% 14% 1	464
	21st to end	Night	25% 10% 26% 24% 13% 2	731
September	1st to 10th	Night	27% 7% 25% 32% 9% 1	720
	11th to 20th	Night	26% 8% 26% 27% 11% 2	720
	21st to end	Night	26% 13% 26% 23% 11% 1	720
October	1st to 10th	Night	27% 12% 26% 27% 7% 1	720
	11th to 20th	Night	37% 12% 26% 17% 8%	720
	21st to end	Night	39% 13% 27% 16% 4	792
November	1st to 10th	Night	33% 15% 29% 18% 4 1	740
	11th to 20th	Night	31% 17% 28% 17% 7% 1	760
	21st to end	Night	34% 17% 29% 16% 4	823
December	1st to 10th	Night	32% 15% 28% 19% 6% 1	850
	11th to 20th	Night	26% 17% 32% 19% 5% 1	850
	21st to end	Night	31% 18% 30% 17% 4 1	902

Page generated at 2024-03-03 06:28:55. Version ac07

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