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 2024-11-02.

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% 13% 4 10% 6% 5% 5% 4 5% 6% 24%	101421
	Night	18% 14% 5% 10% 6% 5% 4 3 4 5% 23%	97567
Transparency	Day	59% 7% 11% 15% 7% 1	101181
	Night	62% 7% 11% 14% 6% 1	97428
Seeing	Day	27% 18% 30% 17% 6% 2	15077
	Night	27% 14% 30% 22% 7% 1	23589

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% 20% 8% 19% 9% 5% 4 4 4 3 10%	2517
	11th to 20th	Day	13% 14% 7% 19% 11% 8% 4 3 4 4 13%	2520
	21st to end	Day	9% 16% 9% 15% 6% 6% 6% 4 5% 6% 19%	2772
February	1st to 10th	Day	8% 16% 6% 16% 12% 8% 7% 3 4 4 16%	1530
	11th to 20th	Day	12% 19% 6% 16% 7% 7% 5% 4 5% 4 15%	1782
	21st to end	Day	13% 16% 6% 13% 7% 6% 5% 4 4 5% 20%	1570
March	1st to 10th	Day	14% 17% 5% 12% 7% 4 4 3 3 4 26%	3116
	11th to 20th	Day	15% 20% 6% 15% 5% 5% 4 3 3 4 19%	3254
	21st to end	Day	12% 17% 5% 12% 5% 3 4 3 4 5% 31%	4151
April	1st to 10th	Day	23% 16% 5% 10% 5% 4 4 2 3 5% 24%	2280
	11th to 20th	Day	20% 13% 4 9% 5% 4 4 3 4 5% 30%	2319
	21st to end	Day	21% 14% 3 10% 4 4 4 2 4 6% 27%	2470
May	1st to 10th	Day	21% 11% 4 8% 5% 5% 5% 3 5% 6% 25%	4352
	11th to 20th	Day	17% 9% 4 8% 5% 5% 5% 4 6% 8% 30%	4398
	21st to end	Day	19% 8% 3 8% 5% 5% 5% 4 6% 7% 28%	4859
June	1st to 10th	Day	22% 10% 3 8% 6% 5% 5% 4 5% 7% 25%	2850
	11th to 20th	Day	21% 8% 3 6% 5% 5% 4 5% 5% 8% 29%	2850
	21st to end	Day	26% 9% 3 8% 6% 6% 5% 4 5% 6% 24%	2850
July	1st to 10th	Day	19% 8% 3 9% 6% 4 5% 4 7% 8% 26%	4479
	11th to 20th	Day	19% 8% 3 9% 7% 5% 5% 4 6% 7% 26%	4440
	21st to end	Day	16% 7% 2 7% 5% 5% 6% 5% 7% 8% 31%	4814
August	1st to 10th	Day	19% 8% 3 8% 5% 6% 5% 5% 7% 10% 25%	4423
	11th to 20th	Day	22% 9% 3 8% 5% 5% 5% 5% 7% 8% 23%	4121
	21st to end	Day	22% 8% 3 8% 5% 5% 4 4 4 6% 30%	4281
September	1st to 10th	Day	21% 8% 3 7% 4 4 5% 3 6% 7% 32%	2280
	11th to 20th	Day	20% 8% 3 7% 3 4 3 3 6% 7% 36%	2152
	21st to end	Day	27% 9% 3 6% 4 4 4 3 5% 6% 30%	2090
October	1st to 10th	Day	26% 11% 3 8% 4 3 4 3 4 5% 28%	2025
	11th to 20th	Day	25% 21% 5% 9% 4 4 3 3 5% 4 18%	1767
	21st to end	Day	29% 19% 4 8% 4 3 3 2 4 4 20%	1881
November	1st to 10th	Day	22% 20% 5% 10% 3 4 4 3 3 5% 21%	1680
	11th to 20th	Day	22% 22% 6% 12% 5% 3 4 2 3 4 17%	1630
	21st to end	Day	19% 23% 8% 14% 6% 4 3 3 3 5% 12%	1387
December	1st to 10th	Day	20% 21% 6% 15% 10% 4 4 2 3 3 11%	1330
	11th to 20th	Day	19% 21% 6% 14% 7% 4 4 3 3 4 15%	1668
	21st to end	Day	20% 21% 7% 11% 10% 5% 4 2 4 5% 11%	2533
January	1st to 10th	Night	13% 21% 8% 14% 9% 8% 6% 3 4 3 10%	4429
	11th to 20th	Night	12% 15% 6% 18% 13% 9% 5% 2 4 3 14%	4440
	21st to end	Night	8% 15% 7% 14% 8% 9% 6% 5% 5% 5% 17%	4884
February	1st to 10th	Night	10% 16% 6% 12% 9% 7% 7% 5% 5% 5% 19%	2646
	11th to 20th	Night	11% 20% 7% 14% 8% 6% 6% 4 5% 5% 16%	2284
	21st to end	Night	11% 19% 6% 12% 6% 6% 6% 3 4 5% 22%	1884
March	1st to 10th	Night	19% 16% 4 11% 5% 5% 6% 4 4 5% 22%	3724
	11th to 20th	Night	14% 21% 6% 13% 6% 5% 5% 2 4 4 20%	3704
	21st to end	Night	13% 15% 5% 11% 6% 5% 4 3 5% 5% 26%	3480
April	1st to 10th	Night	20% 19% 5% 9% 5% 4 3 3 4 4 23%	1900
	11th to 20th	Night	22% 13% 3 7% 4 4 4 4 5% 6% 29%	1808
	21st to end	Night	20% 13% 4 8% 4 4 3 3 5% 5% 31%	1710
May	1st to 10th	Night	21% 10% 3 8% 5% 5% 4 4 4 5% 30%	2619
	11th to 20th	Night	19% 10% 3 6% 4 4 4 4 6% 8% 33%	2495
	21st to end	Night	22% 7% 3 7% 5% 5% 4 4 6% 7% 30%	2712
June	1st to 10th	Night	21% 10% 4 7% 5% 4 5% 3 5% 7% 29%	1330
	11th to 20th	Night	19% 8% 3 6% 6% 4 3 4 5% 7% 34%	1330
	21st to end	Night	23% 9% 4 7% 5% 5% 4 3 6% 7% 28%	1330
July	1st to 10th	Night	19% 8% 3 9% 6% 5% 5% 4 6% 7% 27%	2477
	11th to 20th	Night	18% 8% 3 8% 6% 4 5% 4 6% 8% 30%	2520
	21st to end	Night	14% 6% 2 5% 4 4 4 4 6% 8% 43%	2739
August	1st to 10th	Night	16% 8% 2 8% 5% 5% 6% 3 7% 8% 32%	2506
	11th to 20th	Night	20% 9% 3 8% 4 5% 4 4 6% 7% 29%	2675
	21st to end	Night	20% 8% 3 7% 5% 5% 5% 4 4 6% 33%	3373
September	1st to 10th	Night	22% 7% 2 5% 4 4 3 2 5% 5% 40%	1900
	11th to 20th	Night	20% 9% 3 7% 4 4 3 3 5% 6% 37%	2028
	21st to end	Night	21% 9% 3 7% 4 4 4 3 4 5% 36%	2090
October	1st to 10th	Night	21% 12% 3 7% 4 3 3 3 4 6% 33%	2152
	11th to 20th	Night	28% 15% 3 8% 5% 3 4 3 4 5% 23%	2413
	21st to end	Night	26% 18% 4 8% 4 4 4 3 4 5% 20%	2717
November	1st to 10th	Night	21% 19% 5% 8% 5% 4 4 3 4 5% 21%	2421
	11th to 20th	Night	21% 18% 5% 12% 5% 4 5% 3 4 4 18%	2548
	21st to end	Night	22% 20% 7% 14% 7% 5% 3 3 3 4 13%	2792
December	1st to 10th	Night	19% 21% 8% 15% 8% 5% 3 3 3 4 12%	2850
	11th to 20th	Night	21% 16% 7% 15% 8% 5% 4 3 4 3 15%	3531
	21st to end	Night	19% 24% 7% 12% 7% 5% 4 3 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	61% 6% 8% 14% 10% 2	3119
	11th to 20th	Day	70% 5% 6% 13% 6%	3254
	21st to end	Day	55% 5% 6% 17% 13% 4	4151
April	1st to 10th	Day	65% 4 10% 11% 8% 3	2280
	11th to 20th	Day	56% 5% 8% 17% 11% 2	2319
	21st to end	Day	59% 5% 9% 13% 12% 2	2470
May	1st to 10th	Day	55% 9% 11% 13% 10% 1	4366
	11th to 20th	Day	48% 11% 15% 18% 7% 1	4402
	21st to end	Day	52% 8% 10% 15% 13% 2	4859
June	1st to 10th	Day	57% 8% 9% 16% 8% 2	2850
	11th to 20th	Day	51% 8% 13% 17% 9% 2	2850
	21st to end	Day	60% 8% 10% 13% 9%	2850
July	1st to 10th	Day	53% 8% 13% 23% 4	4409
	11th to 20th	Day	55% 8% 17% 16% 3	4365
	21st to end	Day	48% 9% 17% 21% 5%	4661
August	1st to 10th	Day	53% 9% 17% 17% 3	4409
	11th to 20th	Day	55% 10% 19% 13% 3	4162
	21st to end	Day	54% 8% 13% 15% 11%	4281
September	1st to 10th	Day	51% 7% 15% 19% 7%	2280
	11th to 20th	Day	48% 7% 18% 20% 7%	2152
	21st to end	Day	56% 7% 13% 17% 7%	2090
October	1st to 10th	Day	59% 6% 11% 17% 7%	2025
	11th to 20th	Day	70% 7% 10% 12% 1	1767
	21st to end	Day	67% 5% 11% 13% 3	1881
November	1st to 10th	Day	67% 6% 9% 13% 4	1680
	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	65% 6% 7% 13% 8% 1	3734
	11th to 20th	Night	68% 6% 9% 12% 5% 1	3705
	21st to end	Night	57% 6% 8% 18% 8% 3	3480
April	1st to 10th	Night	64% 5% 9% 12% 9% 2	1900
	11th to 20th	Night	55% 6% 9% 18% 11% 1	1808
	21st to end	Night	55% 6% 9% 18% 11% 1	1710
May	1st to 10th	Night	52% 9% 10% 18% 9% 1	2625
	11th to 20th	Night	45% 10% 17% 20% 8%	2496
	21st to end	Night	50% 9% 12% 17% 11% 1	2713
June	1st to 10th	Night	54% 8% 10% 19% 6% 2	1330
	11th to 20th	Night	47% 9% 13% 17% 11% 2	1330
	21st to end	Night	54% 9% 13% 15% 10%	1330
July	1st to 10th	Night	54% 8% 15% 19% 4	2437
	11th to 20th	Night	50% 9% 20% 17% 4	2472
	21st to end	Night	38% 9% 23% 22% 8%	2651
August	1st to 10th	Night	49% 9% 18% 18% 6%	2496
	11th to 20th	Night	53% 10% 20% 14% 3	2700
	21st to end	Night	50% 8% 13% 22% 7%	3373
September	1st to 10th	Night	46% 8% 13% 24% 9%	1900
	11th to 20th	Night	49% 7% 16% 22% 5%	2028
	21st to end	Night	50% 7% 13% 24% 6%	2090
October	1st to 10th	Night	53% 6% 14% 18% 9% 1	2152
	11th to 20th	Night	63% 8% 11% 14% 4	2413
	21st to end	Night	68% 5% 10% 11% 5% 1	2717
November	1st to 10th	Night	65% 7% 11% 13% 4 1	2421
	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%	460
	11th to 20th	Day	27% 19% 33% 15% 6%	460
	21st to end	Day	27% 25% 28% 14% 4 1	506
April	1st to 10th	Day	31% 22% 28% 12% 5% 1	460
	11th to 20th	Day	31% 22% 26% 12% 7% 2	452
	21st to end	Day	30% 21% 33% 12% 3 1	460
May	1st to 10th	Day	32% 20% 28% 12% 6% 2	463
	11th to 20th	Day	25% 18% 31% 20% 6% 1	487
	21st to end	Day	30% 22% 29% 15% 4 1	538
June	1st to 10th	Day	27% 16% 31% 19% 6% 1	680
	11th to 20th	Day	26% 17% 28% 20% 9% 1	680
	21st to end	Day	30% 11% 31% 20% 7% 1	680
July	1st to 10th	Day	21% 15% 33% 24% 6% 1	511
	11th to 20th	Day	20% 14% 34% 23% 7% 2	484
	21st to end	Day	24% 12% 29% 25% 10% 1	532
August	1st to 10th	Day	24% 12% 32% 22% 7% 3	486
	11th to 20th	Day	22% 7% 30% 27% 11% 3	479
	21st to end	Day	25% 16% 28% 15% 10% 6%	539
September	1st to 10th	Day	27% 15% 29% 19% 7% 4	490
	11th to 20th	Day	21% 14% 27% 22% 11% 4	490
	21st to end	Day	26% 17% 26% 16% 11% 4	490
October	1st to 10th	Day	27% 18% 25% 19% 7% 3	490
	11th to 20th	Day	39% 17% 25% 10% 8% 2	420
	21st to end	Day	39% 16% 28% 13% 4	429
November	1st to 10th	Day	35% 21% 28% 11% 4	368
	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% 16% 35% 22% 5%	760
	11th to 20th	Night	27% 18% 30% 19% 5% 1	760
	21st to end	Night	23% 19% 32% 19% 6% 1	836
April	1st to 10th	Night	31% 14% 29% 22% 4	760
	11th to 20th	Night	31% 15% 27% 20% 6% 1	684
	21st to end	Night	29% 19% 31% 18% 4	570
May	1st to 10th	Night	29% 14% 29% 24% 5%	446
	11th to 20th	Night	25% 10% 33% 25% 7%	374
	21st to end	Night	29% 13% 32% 20% 5%	411
June	1st to 10th	Night	25% 9% 34% 25% 5% 1	380
	11th to 20th	Night	23% 9% 29% 29% 9% 1	380
	21st to end	Night	24% 10% 28% 29% 8%	380
July	1st to 10th	Night	20% 8% 32% 30% 9% 1	370
	11th to 20th	Night	16% 10% 28% 32% 13% 1	368
	21st to end	Night	20% 6% 27% 36% 11% 1	416
August	1st to 10th	Night	19% 7% 26% 35% 13% 1	378
	11th to 20th	Night	21% 8% 26% 30% 15% 1	491
	21st to end	Night	25% 10% 26% 24% 14% 2	772
September	1st to 10th	Night	27% 7% 26% 31% 9% 1	760
	11th to 20th	Night	24% 8% 25% 28% 13% 2	760
	21st to end	Night	26% 13% 26% 23% 12% 1	760
October	1st to 10th	Night	27% 13% 26% 26% 8% 1	760
	11th to 20th	Night	37% 11% 26% 17% 8%	760
	21st to end	Night	38% 13% 27% 17% 4	836
November	1st to 10th	Night	34% 15% 29% 18% 4 1	745
	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 2024-10-30 01:22:57. Version ac07

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