Embrun
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Embrun clear sky chart from 2005-11-06 to 2024-12-09.

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	17% 9% 3 8% 5% 5% 5% 4 5% 7% 33%	101849
	Night	18% 11% 4 8% 5% 4 4 3 5% 6% 31%	97938
Transparency	Day	50% 5% 13% 22% 9% 1	105319
	Night	53% 4 12% 20% 10% 1	102557
Seeing	Day	21% 8% 27% 26% 14% 5%	14589
	Night	22% 7% 27% 32% 11% 1	23689

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	16% 15% 5% 13% 6% 5% 5% 3 5% 4 23%	2517
	11th to 20th	Day	14% 14% 5% 12% 8% 6% 5% 4 5% 5% 22%	2520
	21st to end	Day	15% 17% 6% 12% 6% 7% 6% 4 5% 5% 18%	2845
February	1st to 10th	Day	15% 17% 4 10% 7% 4 4 4 5% 5% 24%	1710
	11th to 20th	Day	14% 13% 5% 11% 7% 4 4 4 5% 6% 27%	1693
	21st to end	Day	18% 14% 4 8% 5% 5% 5% 4 5% 5% 26%	1570
March	1st to 10th	Day	19% 11% 4 9% 7% 5% 5% 3 5% 6% 26%	3116
	11th to 20th	Day	13% 16% 5% 9% 5% 5% 5% 4 5% 6% 28%	3435
	21st to end	Day	14% 7% 3 7% 5% 4 4 3 5% 7% 40%	4061
April	1st to 10th	Day	21% 11% 3 7% 5% 4 4 3 4 6% 33%	2280
	11th to 20th	Day	21% 8% 3 7% 4 4 4 3 4 6% 36%	2254
	21st to end	Day	22% 10% 3 7% 5% 4 4 3 4 5% 31%	2401
May	1st to 10th	Day	20% 9% 3 7% 4 4 5% 4 6% 7% 31%	4426
	11th to 20th	Day	18% 8% 3 7% 5% 5% 4 3 5% 7% 33%	4398
	21st to end	Day	15% 7% 2 7% 5% 5% 5% 4 6% 7% 38%	4837
June	1st to 10th	Day	22% 8% 2 7% 5% 5% 4 3 5% 8% 29%	2660
	11th to 20th	Day	13% 6% 2 6% 5% 5% 5% 4 7% 8% 38%	2660
	21st to end	Day	20% 8% 2 6% 5% 5% 4 5% 6% 8% 32%	2660
July	1st to 10th	Day	12% 6% 2 7% 5% 6% 6% 4 7% 9% 36%	4440
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 5% 7% 9% 38%	4440
	21st to end	Day	11% 6% 2 5% 4 4 5% 4 7% 9% 43%	4814
August	1st to 10th	Day	14% 7% 3 8% 5% 5% 5% 4 6% 8% 35%	4401
	11th to 20th	Day	16% 6% 2 6% 4 4 4 4 7% 9% 38%	3953
	21st to end	Day	16% 5% 2 6% 4 4 4 4 6% 9% 39%	4180
September	1st to 10th	Day	13% 5% 1 7% 5% 4 5% 4 6% 8% 43%	2280
	11th to 20th	Day	13% 5% 2 5% 4 3 4 3 5% 8% 48%	2261
	21st to end	Day	17% 6% 2 6% 4 3 4 4 5% 7% 41%	2060
October	1st to 10th	Day	19% 8% 2 6% 5% 5% 4 4 5% 6% 35%	1900
	11th to 20th	Day	20% 9% 3 8% 5% 5% 5% 4 6% 6% 30%	1900
	21st to end	Day	25% 10% 3 6% 4 5% 5% 4 4 5% 28%	1914
November	1st to 10th	Day	16% 9% 3 7% 5% 5% 5% 5% 7% 6% 33%	1761
	11th to 20th	Day	18% 12% 4 8% 5% 4 5% 4 5% 7% 30%	1640
	21st to end	Day	21% 14% 5% 9% 5% 6% 5% 4 5% 5% 22%	1600
December	1st to 10th	Day	22% 16% 5% 10% 5% 5% 5% 4 5% 6% 17%	1584
	11th to 20th	Day	21% 16% 5% 8% 5% 4 4 4 5% 5% 24%	1906
	21st to end	Day	27% 17% 5% 11% 4 4 4 2 3 3 20%	2772
January	1st to 10th	Night	18% 17% 6% 12% 6% 5% 4 3 5% 5% 21%	4429
	11th to 20th	Night	13% 14% 5% 14% 7% 5% 5% 4 5% 6% 21%	4440
	21st to end	Night	17% 19% 7% 11% 5% 5% 4 2 3 5% 21%	4806
February	1st to 10th	Night	15% 14% 5% 11% 6% 6% 6% 4 5% 6% 23%	2470
	11th to 20th	Night	14% 13% 4 11% 6% 5% 4 4 5% 5% 28%	2371
	21st to end	Night	16% 15% 4 7% 7% 4 4 3 4 5% 30%	1884
March	1st to 10th	Night	20% 12% 4 8% 5% 5% 4 3 4 5% 32%	3724
	11th to 20th	Night	17% 16% 4 10% 6% 5% 3 2 5% 5% 27%	3521
	21st to end	Night	15% 11% 3 7% 4 4 4 3 4 5% 40%	3570
April	1st to 10th	Night	22% 10% 3 7% 6% 4 4 3 4 6% 32%	1900
	11th to 20th	Night	20% 9% 3 7% 5% 4 4 4 4 5% 35%	1875
	21st to end	Night	21% 9% 3 7% 4 4 3 3 5% 6% 34%	1793
May	1st to 10th	Night	20% 9% 2 8% 5% 5% 5% 4 6% 7% 28%	2514
	11th to 20th	Night	20% 9% 3 6% 4 5% 4 3 5% 6% 35%	2495
	21st to end	Night	14% 7% 2 7% 4 5% 5% 4 6% 8% 38%	2738
June	1st to 10th	Night	16% 7% 2 8% 5% 5% 6% 5% 6% 8% 31%	1520
	11th to 20th	Night	15% 6% 3 6% 4 4 4 4 6% 7% 41%	1520
	21st to end	Night	18% 7% 2 7% 4 4 4 4 6% 8% 35%	1520
July	1st to 10th	Night	13% 8% 3 8% 5% 5% 6% 4 6% 7% 34%	2520
	11th to 20th	Night	13% 6% 2 6% 4 5% 4 4 7% 7% 42%	2520
	21st to end	Night	11% 7% 2 7% 4 4 5% 4 7% 7% 42%	2739
August	1st to 10th	Night	13% 8% 2 7% 5% 5% 3 4 6% 8% 40%	2524
	11th to 20th	Night	14% 6% 2 7% 4 4 4 4 7% 7% 41%	2844
	21st to end	Night	12% 6% 3 7% 5% 4 5% 4 6% 8% 41%	3476
September	1st to 10th	Night	11% 5% 3 7% 5% 4 5% 3 5% 7% 45%	1900
	11th to 20th	Night	14% 5% 2 4 3 3 3 3 5% 7% 50%	1919
	21st to end	Night	16% 6% 2 6% 4 4 4 4 4 6% 44%	2118
October	1st to 10th	Night	19% 6% 2 6% 4 4 4 3 6% 7% 37%	2280
	11th to 20th	Night	20% 8% 3 8% 5% 6% 4 4 5% 7% 33%	2280
	21st to end	Night	22% 10% 4 8% 5% 5% 4 3 4 7% 29%	2684
November	1st to 10th	Night	19% 11% 3 7% 5% 4 4 3 5% 6% 34%	2537
	11th to 20th	Night	18% 9% 3 8% 6% 5% 5% 3 5% 5% 32%	2756
	21st to end	Night	21% 13% 4 10% 5% 4 4 4 5% 6% 25%	2800
December	1st to 10th	Night	20% 16% 5% 11% 7% 6% 5% 4 4 5% 17%	2779
	11th to 20th	Night	23% 14% 4 9% 5% 4 4 3 4 4 26%	3288
	21st to end	Night	31% 16% 4 10% 4 3 4 3 3 4 18%	4884

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	63% 4 16% 10% 5% 1	2518
	11th to 20th	Day	61% 5% 13% 13% 7% 1	2520
	21st to end	Day	67% 5% 13% 9% 5%	2845
February	1st to 10th	Day	60% 5% 10% 20% 4 2	1710
	11th to 20th	Day	56% 5% 14% 17% 8% 1	1702
	21st to end	Day	59% 3 13% 14% 10% 1	1570
March	1st to 10th	Day	59% 4 10% 18% 8% 1	3119
	11th to 20th	Day	56% 5% 13% 16% 9% 1	3435
	21st to end	Day	41% 6% 9% 24% 16% 3	4061
April	1st to 10th	Day	53% 4 8% 20% 12% 3	2280
	11th to 20th	Day	50% 4 8% 22% 15% 2	2254
	21st to end	Day	55% 4 9% 15% 14% 3	2401
May	1st to 10th	Day	50% 5% 11% 22% 9% 2	4440
	11th to 20th	Day	51% 5% 14% 19% 9% 1	4402
	21st to end	Day	43% 6% 13% 23% 14% 1	4837
June	1st to 10th	Day	53% 6% 11% 18% 11% 1	2660
	11th to 20th	Day	42% 6% 13% 25% 12% 2	2660
	21st to end	Day	49% 6% 14% 21% 9% 1	2660
July	1st to 10th	Day	44% 3 15% 27% 12% 1	4370
	11th to 20th	Day	41% 4 15% 31% 8%	4365
	21st to end	Day	37% 5% 14% 34% 10%	4661
August	1st to 10th	Day	47% 4 16% 24% 9%	4387
	11th to 20th	Day	42% 4 17% 29% 7%	3992
	21st to end	Day	42% 4 17% 25% 11% 1	4180
September	1st to 10th	Day	38% 5% 15% 29% 12%	2280
	11th to 20th	Day	36% 4 13% 33% 14% 1	2261
	21st to end	Day	42% 5% 16% 27% 10%	2060
October	1st to 10th	Day	47% 3 11% 31% 8%	3160
	11th to 20th	Day	47% 3 15% 27% 7%	3140
	21st to end	Day	49% 3 17% 24% 7%	3126
November	1st to 10th	Day	49% 6% 14% 23% 7% 1	1761
	11th to 20th	Day	54% 5% 13% 18% 10%	1640
	21st to end	Day	63% 6% 13% 13% 6%	1600
December	1st to 10th	Day	68% 6% 13% 11% 2	1584
	11th to 20th	Day	63% 6% 13% 14% 4	1906
	21st to end	Day	72% 3 8% 15% 3	2772
January	1st to 10th	Night	66% 3 16% 11% 4	4429
	11th to 20th	Night	63% 5% 16% 11% 5%	4440
	21st to end	Night	68% 4 11% 11% 6% 1	4806
February	1st to 10th	Night	62% 5% 10% 16% 6% 1	2470
	11th to 20th	Night	57% 4 11% 20% 8%	2373
	21st to end	Night	57% 4 9% 19% 10% 1	1884
March	1st to 10th	Night	55% 4 9% 20% 10% 2	3734
	11th to 20th	Night	60% 4 13% 15% 8% 2	3522
	21st to end	Night	45% 4 6% 24% 17% 3	3570
April	1st to 10th	Night	54% 4 9% 18% 14% 2	1900
	11th to 20th	Night	51% 4 8% 21% 15% 1	1875
	21st to end	Night	50% 4 9% 18% 16% 3	1793
May	1st to 10th	Night	53% 6% 11% 18% 9% 3	2520
	11th to 20th	Night	48% 6% 12% 19% 13% 2	2496
	21st to end	Night	40% 7% 13% 20% 17% 2	2739
June	1st to 10th	Night	48% 7% 13% 20% 11% 1	1520
	11th to 20th	Night	41% 5% 13% 22% 17% 2	1520
	21st to end	Night	46% 6% 14% 20% 14% 1	1520
July	1st to 10th	Night	47% 5% 14% 21% 13% 1	2480
	11th to 20th	Night	40% 4 15% 33% 8%	2472
	21st to end	Night	40% 6% 15% 24% 14%	2651
August	1st to 10th	Night	44% 4 16% 26% 10%	2514
	11th to 20th	Night	42% 3 16% 31% 7%	2871
	21st to end	Night	41% 4 16% 26% 12% 2	3476
September	1st to 10th	Night	38% 6% 11% 28% 15% 1	1900
	11th to 20th	Night	34% 5% 13% 35% 12% 1	1919
	21st to end	Night	41% 5% 13% 29% 12%	2118
October	1st to 10th	Night	43% 3 13% 31% 10%	3800
	11th to 20th	Night	44% 3 15% 29% 9%	3779
	21st to end	Night	49% 4 16% 22% 9%	4422
November	1st to 10th	Night	52% 4 14% 21% 9% 1	2537
	11th to 20th	Night	53% 4 12% 18% 10% 1	2756
	21st to end	Night	61% 5% 13% 17% 5%	2800
December	1st to 10th	Night	68% 5% 10% 14% 3	2779
	11th to 20th	Night	62% 4 9% 16% 7% 1	3288
	21st to end	Night	72% 3 9% 13% 3	4884

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% 10% 24% 28% 9% 1	180
	11th to 20th	Day	26% 8% 32% 24% 8% 2	180
	21st to end	Day	19% 7% 31% 33% 9% 1	220
February	1st to 10th	Day	30% 11% 34% 19% 6%	270
	11th to 20th	Day	21% 12% 39% 25% 3	300
	21st to end	Day	27% 8% 31% 29% 5%	382
March	1st to 10th	Day	22% 9% 30% 30% 9%	460
	11th to 20th	Day	19% 13% 35% 25% 7%	460
	21st to end	Day	26% 8% 31% 22% 9% 3	506
April	1st to 10th	Day	25% 10% 31% 23% 10% 2	460
	11th to 20th	Day	26% 14% 27% 18% 12% 4	452
	21st to end	Day	28% 9% 29% 20% 10% 3	460
May	1st to 10th	Day	25% 7% 28% 25% 11% 3	463
	11th to 20th	Day	16% 10% 31% 26% 11% 7%	487
	21st to end	Day	18% 7% 30% 25% 15% 4	529
June	1st to 10th	Day	25% 7% 23% 29% 11% 5%	490
	11th to 20th	Day	15% 9% 27% 25% 19% 6%	490
	21st to end	Day	22% 9% 23% 27% 14% 5%	490
July	1st to 10th	Day	15% 4 21% 33% 20% 7%	485
	11th to 20th	Day	13% 5% 27% 29% 19% 6%	484
	21st to end	Day	14% 5% 22% 33% 20% 6%	532
August	1st to 10th	Day	15% 4 17% 34% 23% 6%	486
	11th to 20th	Day	15% 3 18% 26% 26% 12%	479
	21st to end	Day	15% 6% 22% 27% 20% 10%	539
September	1st to 10th	Day	14% 7% 23% 25% 18% 13%	490
	11th to 20th	Day	13% 4 20% 23% 25% 17%	490
	21st to end	Day	19% 7% 25% 24% 18% 8%	490
October	1st to 10th	Day	23% 8% 25% 21% 17% 7%	490
	11th to 20th	Day	22% 11% 32% 22% 11% 3	490
	21st to end	Day	31% 9% 23% 27% 9%	446
November	1st to 10th	Day	23% 13% 27% 24% 11% 1	395
	11th to 20th	Day	24% 9% 36% 22% 6% 3	240
	21st to end	Day	27% 14% 31% 21% 7% 2	200
December	1st to 10th	Day	28% 10% 27% 27% 7% 2	196
	11th to 20th	Day	26% 16% 34% 21% 4 1	180
	21st to end	Day	32% 9% 33% 18% 7% 2	198
January	1st to 10th	Night	26% 9% 29% 30% 6%	760
	11th to 20th	Night	26% 9% 29% 30% 6% 1	760
	21st to end	Night	21% 6% 30% 34% 9% 1	836
February	1st to 10th	Night	22% 7% 36% 29% 6%	760
	11th to 20th	Night	21% 10% 35% 29% 6%	743
	21st to end	Night	23% 8% 33% 31% 5%	628
March	1st to 10th	Night	23% 9% 30% 31% 7%	760
	11th to 20th	Night	24% 10% 32% 29% 6%	760
	21st to end	Night	22% 9% 27% 31% 10%	836
April	1st to 10th	Night	26% 9% 29% 30% 6%	760
	11th to 20th	Night	23% 10% 31% 26% 10%	751
	21st to end	Night	25% 8% 27% 29% 10% 1	653
May	1st to 10th	Night	24% 6% 24% 33% 10% 2	380
	11th to 20th	Night	20% 6% 30% 34% 9% 1	374
	21st to end	Night	16% 3 33% 35% 13%	411
June	1st to 10th	Night	18% 5% 24% 41% 12% 1	380
	11th to 20th	Night	16% 6% 25% 40% 13% 1	380
	21st to end	Night	19% 4 24% 37% 15% 1	380
July	1st to 10th	Night	10% 4 23% 45% 19%	370
	11th to 20th	Night	12% 3 19% 46% 19% 1	368
	21st to end	Night	13% 2 19% 48% 16% 1	416
August	1st to 10th	Night	14% 3 18% 44% 20% 1	383
	11th to 20th	Night	15% 2 13% 39% 29% 2	597
	21st to end	Night	15% 4 19% 39% 21% 2	836
September	1st to 10th	Night	14% 4 20% 41% 20% 1	760
	11th to 20th	Night	16% 4 17% 33% 26% 4	760
	21st to end	Night	18% 4 23% 29% 23% 2	760
October	1st to 10th	Night	23% 4 24% 30% 17% 2	760
	11th to 20th	Night	23% 6% 29% 31% 11% 1	760
	21st to end	Night	28% 9% 26% 29% 8%	836
November	1st to 10th	Night	26% 9% 26% 28% 10% 1	780
	11th to 20th	Night	23% 10% 33% 24% 10% 1	800
	21st to end	Night	26% 9% 31% 26% 8%	800
December	1st to 10th	Night	29% 7% 31% 26% 6% 1	795
	11th to 20th	Night	27% 10% 31% 25% 5% 1	760
	21st to end	Night	33% 8% 30% 24% 6%	836

Page generated at 2024-12-06 03:54:48. Version ac07

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