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 2024-01-16.

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 6% 6% 3 5% 5% 5% 7% 33%	74771
	Night	18% 10% 4 7% 6% 3 5% 4 5% 6% 32%	75031
Transparency	Day	50% 5% 12% 21% 10% 1	74476
	Night	53% 5% 11% 20% 10% 1	74860
Seeing	Day	21% 8% 27% 26% 14% 5%	13402
	Night	22% 7% 27% 32% 11% 1	22595

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	18% 16% 6% 12% 6% 4 4 4 4 4 21%	1517
	11th to 20th	Day	18% 16% 5% 9% 8% 3 4 5% 3 6% 23%	1486
	21st to end	Day	14% 12% 5% 10% 7% 6% 5% 5% 5% 6% 24%	1629
February	1st to 10th	Day	15% 16% 5% 10% 7% 4 4 5% 5% 5% 24%	1620
	11th to 20th	Day	15% 13% 5% 9% 7% 2 4 5% 5% 7% 27%	1602
	21st to end	Day	19% 13% 4 8% 6% 3 6% 5% 5% 5% 25%	1480
March	1st to 10th	Day	15% 10% 5% 9% 9% 4 6% 4 4 6% 29%	1797
	11th to 20th	Day	17% 11% 5% 6% 6% 3 5% 5% 4 6% 31%	1949
	21st to end	Day	19% 9% 4 5% 4 3 4 4 5% 6% 36%	2313
April	1st to 10th	Day	21% 9% 4 6% 6% 3 4 3 4 6% 33%	2160
	11th to 20th	Day	21% 7% 3 6% 5% 3 4 3 4 6% 37%	2134
	21st to end	Day	23% 9% 3 7% 6% 3 5% 4 5% 5% 31%	2274
May	1st to 10th	Day	20% 8% 4 5% 5% 3 6% 4 5% 7% 34%	2520
	11th to 20th	Day	16% 7% 3 5% 6% 4 4 4 5% 6% 40%	2478
	21st to end	Day	16% 6% 3 5% 6% 4 5% 5% 6% 7% 38%	2725
June	1st to 10th	Day	23% 7% 3 6% 6% 4 5% 5% 5% 8% 29%	2520
	11th to 20th	Day	14% 6% 2 5% 6% 3 6% 5% 6% 8% 39%	2520
	21st to end	Day	19% 7% 3 5% 6% 3 5% 5% 6% 8% 32%	2520
July	1st to 10th	Day	11% 5% 3 5% 5% 4 5% 6% 6% 8% 42%	2520
	11th to 20th	Day	12% 6% 2 5% 5% 3 5% 6% 7% 10% 38%	2520
	21st to end	Day	12% 5% 3 5% 5% 4 6% 6% 7% 9% 38%	2744
August	1st to 10th	Day	11% 6% 2 6% 7% 4 5% 5% 5% 9% 39%	2498
	11th to 20th	Day	12% 5% 2 6% 5% 3 5% 6% 7% 9% 40%	2254
	21st to end	Day	13% 6% 2 5% 5% 3 5% 5% 6% 9% 41%	2376
September	1st to 10th	Day	13% 5% 2 6% 6% 3 5% 6% 5% 8% 42%	2160
	11th to 20th	Day	14% 4 2 4 5% 3 4 4 5% 8% 47%	2142
	21st to end	Day	17% 6% 3 5% 5% 3 4 5% 5% 7% 40%	1952
October	1st to 10th	Day	20% 8% 2 6% 5% 3 5% 5% 5% 6% 35%	1800
	11th to 20th	Day	21% 8% 3 7% 7% 4 5% 4 6% 6% 28%	1800
	21st to end	Day	26% 9% 4 5% 6% 4 5% 4 4 5% 27%	1814
November	1st to 10th	Day	16% 8% 3 6% 5% 4 6% 6% 7% 6% 33%	1671
	11th to 20th	Day	19% 11% 4 7% 6% 3 4 4 5% 7% 28%	1558
	21st to end	Day	20% 13% 5% 8% 6% 4 6% 5% 5% 6% 23%	1520
December	1st to 10th	Day	23% 14% 5% 10% 6% 3 6% 5% 5% 5% 17%	1520
	11th to 20th	Day	22% 15% 5% 7% 6% 3 4 5% 5% 5% 24%	1906
	21st to end	Day	27% 16% 5% 10% 5% 3 4 2 3 3 20%	2772
January	1st to 10th	Night	19% 16% 6% 10% 7% 4 5% 4 4 5% 19%	2649
	11th to 20th	Night	19% 16% 5% 10% 7% 3 4 4 4 4 22%	2602
	21st to end	Night	13% 14% 5% 9% 7% 3 5% 3 4 6% 29%	2722
February	1st to 10th	Night	16% 13% 6% 11% 7% 4 7% 5% 5% 5% 22%	2340
	11th to 20th	Night	15% 11% 5% 10% 7% 4 5% 5% 5% 5% 29%	2242
	21st to end	Night	16% 14% 5% 7% 6% 4 4 4 4 5% 31%	1776
March	1st to 10th	Night	17% 13% 5% 7% 8% 4 5% 4 4 4 29%	2150
	11th to 20th	Night	17% 11% 4 8% 7% 4 3 3 4 4 33%	2007
	21st to end	Night	18% 9% 4 7% 5% 3 4 4 3 5% 39%	2042
April	1st to 10th	Night	23% 9% 3 6% 6% 3 4 4 4 6% 33%	1800
	11th to 20th	Night	20% 7% 4 6% 6% 4 4 4 4 5% 36%	1775
	21st to end	Night	21% 9% 3 6% 5% 3 4 4 5% 7% 33%	1699
May	1st to 10th	Night	22% 8% 2 5% 5% 3 4 4 5% 7% 36%	1440
	11th to 20th	Night	18% 7% 3 6% 4 3 4 3 6% 5% 41%	1415
	21st to end	Night	14% 5% 3 5% 4 3 5% 5% 6% 7% 43%	1550
June	1st to 10th	Night	17% 6% 3 6% 5% 4 6% 6% 6% 9% 31%	1440
	11th to 20th	Night	15% 6% 3 5% 5% 2 5% 5% 6% 7% 41%	1440
	21st to end	Night	17% 6% 3 6% 5% 3 5% 5% 6% 9% 36%	1440
July	1st to 10th	Night	10% 5% 2 5% 5% 3 6% 5% 5% 9% 44%	1440
	11th to 20th	Night	11% 7% 2 5% 5% 2 5% 5% 7% 8% 43%	1440
	21st to end	Night	10% 5% 3 6% 5% 3 5% 5% 7% 9% 43%	1574
August	1st to 10th	Night	10% 7% 2 5% 6% 4 4 4 6% 9% 42%	1436
	11th to 20th	Night	11% 5% 2 6% 5% 3 4 5% 6% 8% 44%	1629
	21st to end	Night	12% 5% 3 5% 4 2 4 5% 6% 8% 44%	1980
September	1st to 10th	Night	12% 5% 3 6% 6% 3 5% 4 5% 7% 44%	1800
	11th to 20th	Night	15% 5% 2 4 4 2 3 4 5% 8% 49%	1818
	21st to end	Night	16% 6% 2 5% 5% 3 4 5% 4 6% 44%	2006
October	1st to 10th	Night	20% 6% 3 6% 5% 3 5% 4 5% 7% 37%	2160
	11th to 20th	Night	20% 8% 3 7% 6% 4 4 4 5% 7% 31%	2160
	21st to end	Night	23% 9% 4 7% 6% 4 5% 4 4 7% 28%	2542
November	1st to 10th	Night	19% 11% 3 6% 5% 3 4 3 4 6% 35%	2407
	11th to 20th	Night	19% 9% 3 7% 7% 3 5% 4 5% 5% 32%	2618
	21st to end	Night	22% 12% 5% 8% 6% 3 4 4 4 6% 25%	2660
December	1st to 10th	Night	20% 15% 5% 10% 8% 4 5% 5% 4 6% 18%	2660
	11th to 20th	Night	24% 13% 4 8% 6% 3 4 4 4 4 26%	3288
	21st to end	Night	31% 16% 4 9% 5% 3 4 4 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	66% 3 10% 14% 5%	1518
	11th to 20th	Day	64% 4 9% 13% 9% 1	1486
	21st to end	Day	60% 5% 13% 14% 8% 1	1629
February	1st to 10th	Day	61% 4 10% 19% 4 2	1620
	11th to 20th	Day	56% 4 13% 17% 8% 1	1611
	21st to end	Day	61% 3 12% 14% 10% 1	1480
March	1st to 10th	Day	58% 4 11% 17% 10% 1	1800
	11th to 20th	Day	53% 4 12% 17% 11% 3	1949
	21st to end	Day	48% 5% 10% 18% 14% 4	2313
April	1st to 10th	Day	53% 4 8% 20% 13% 3	2160
	11th to 20th	Day	49% 4 8% 22% 15% 2	2134
	21st to end	Day	55% 4 9% 15% 14% 3	2274
May	1st to 10th	Day	50% 4 8% 21% 14% 4	2520
	11th to 20th	Day	45% 5% 9% 23% 15% 3	2482
	21st to end	Day	45% 5% 14% 20% 13% 2	2725
June	1st to 10th	Day	53% 6% 11% 18% 11% 1	2520
	11th to 20th	Day	41% 7% 13% 25% 12% 2	2520
	21st to end	Day	49% 6% 14% 20% 10% 1	2520
July	1st to 10th	Day	38% 6% 14% 27% 15% 1	2450
	11th to 20th	Day	38% 7% 16% 28% 10%	2445
	21st to end	Day	40% 7% 17% 26% 10%	2591
August	1st to 10th	Day	41% 7% 17% 25% 10%	2484
	11th to 20th	Day	39% 7% 19% 26% 9% 1	2254
	21st to end	Day	39% 6% 15% 28% 12% 1	2376
September	1st to 10th	Day	38% 6% 15% 28% 12%	2160
	11th to 20th	Day	36% 5% 12% 33% 13% 1	2142
	21st to end	Day	43% 5% 16% 28% 9%	1952
October	1st to 10th	Day	50% 5% 11% 23% 11% 1	1800
	11th to 20th	Day	56% 6% 15% 17% 6% 1	1800
	21st to end	Day	59% 5% 11% 17% 7% 1	1814
November	1st to 10th	Day	49% 6% 14% 22% 7% 1	1671
	11th to 20th	Day	55% 5% 14% 17% 9% 1	1558
	21st to end	Day	62% 6% 13% 13% 6%	1520
December	1st to 10th	Day	68% 6% 13% 11% 2	1520
	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	68% 4 10% 12% 6%	2649
	11th to 20th	Night	66% 4 10% 11% 8% 1	2602
	21st to end	Night	58% 4 9% 17% 10% 1	2722
February	1st to 10th	Night	64% 5% 10% 15% 6% 1	2340
	11th to 20th	Night	57% 4 11% 20% 8%	2244
	21st to end	Night	57% 4 9% 19% 11% 1	1776
March	1st to 10th	Night	59% 4 9% 16% 10% 2	2160
	11th to 20th	Night	55% 4 9% 19% 11% 3	2008
	21st to end	Night	49% 3 7% 20% 15% 4	2042
April	1st to 10th	Night	53% 4 9% 19% 14% 2	1800
	11th to 20th	Night	50% 4 9% 21% 15% 2	1775
	21st to end	Night	51% 4 9% 17% 15% 4	1699
May	1st to 10th	Night	49% 4 8% 18% 16% 5%	1440
	11th to 20th	Night	44% 5% 8% 22% 19% 3	1416
	21st to end	Night	38% 7% 15% 20% 17% 3	1551
June	1st to 10th	Night	48% 7% 13% 21% 11% 1	1440
	11th to 20th	Night	41% 5% 13% 22% 17% 2	1440
	21st to end	Night	44% 7% 15% 20% 14% 1	1440
July	1st to 10th	Night	35% 8% 13% 27% 16% 2	1400
	11th to 20th	Night	36% 6% 15% 31% 12%	1392
	21st to end	Night	36% 9% 15% 26% 14%	1486
August	1st to 10th	Night	38% 7% 19% 23% 12% 1	1426
	11th to 20th	Night	38% 6% 16% 29% 11% 1	1629
	21st to end	Night	37% 6% 16% 29% 12% 1	1980
September	1st to 10th	Night	39% 6% 11% 27% 15% 1	1800
	11th to 20th	Night	35% 5% 14% 34% 11% 1	1818
	21st to end	Night	41% 6% 13% 30% 11%	2006
October	1st to 10th	Night	47% 6% 10% 24% 13% 1	2160
	11th to 20th	Night	52% 5% 13% 21% 8%	2160
	21st to end	Night	57% 5% 13% 17% 8% 1	2542
November	1st to 10th	Night	51% 4 14% 21% 9% 1	2407
	11th to 20th	Night	54% 4 13% 18% 10% 1	2618
	21st to end	Night	61% 5% 13% 16% 5%	2660
December	1st to 10th	Night	67% 5% 10% 14% 4	2660
	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	27% 9% 31% 24% 8% 2	172
	21st to end	Day	18% 7% 33% 31% 9% 2	196
February	1st to 10th	Day	32% 11% 37% 17% 3	240
	11th to 20th	Day	22% 12% 39% 24% 4	269
	21st to end	Day	28% 8% 29% 29% 4	346
March	1st to 10th	Day	21% 9% 30% 31% 9%	420
	11th to 20th	Day	20% 13% 34% 25% 7%	420
	21st to end	Day	27% 8% 27% 24% 10% 3	462
April	1st to 10th	Day	24% 10% 31% 23% 10% 2	420
	11th to 20th	Day	25% 14% 25% 19% 13% 4	412
	21st to end	Day	29% 8% 28% 21% 10% 3	420
May	1st to 10th	Day	25% 8% 28% 25% 11% 4	423
	11th to 20th	Day	15% 10% 32% 26% 11% 6%	447
	21st to end	Day	18% 6% 31% 26% 14% 5%	485
June	1st to 10th	Day	25% 8% 23% 28% 11% 5%	450
	11th to 20th	Day	16% 10% 25% 25% 18% 6%	450
	21st to end	Day	21% 8% 22% 28% 15% 6%	450
July	1st to 10th	Day	16% 3 19% 33% 20% 8%	445
	11th to 20th	Day	12% 5% 27% 30% 20% 6%	444
	21st to end	Day	14% 6% 23% 32% 20% 6%	488
August	1st to 10th	Day	14% 4 17% 35% 23% 7%	446
	11th to 20th	Day	14% 3 18% 26% 27% 12%	439
	21st to end	Day	14% 7% 22% 26% 20% 11%	495
September	1st to 10th	Day	14% 7% 23% 25% 18% 14%	450
	11th to 20th	Day	14% 4 21% 24% 24% 14%	450
	21st to end	Day	18% 7% 25% 24% 18% 8%	450
October	1st to 10th	Day	24% 8% 24% 20% 17% 7%	450
	11th to 20th	Day	23% 10% 32% 22% 10% 3	450
	21st to end	Day	32% 9% 22% 28% 9%	412
November	1st to 10th	Day	24% 13% 26% 24% 12% 1	365
	11th to 20th	Day	27% 8% 35% 21% 7% 3	218
	21st to end	Day	25% 13% 31% 22% 7% 2	180
December	1st to 10th	Day	28% 11% 27% 26% 7% 1	180
	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% 5% 1	744
	21st to end	Night	21% 6% 30% 34% 9% 1	792
February	1st to 10th	Night	23% 7% 36% 28% 6%	720
	11th to 20th	Night	21% 9% 35% 29% 6%	703
	21st to end	Night	23% 7% 33% 31% 5%	592
March	1st to 10th	Night	23% 9% 31% 31% 7%	720
	11th to 20th	Night	23% 10% 32% 29% 6%	720
	21st to end	Night	22% 9% 26% 32% 10% 1	792
April	1st to 10th	Night	26% 8% 29% 30% 6%	720
	11th to 20th	Night	23% 10% 31% 27% 10%	711
	21st to end	Night	25% 8% 27% 29% 10% 1	619
May	1st to 10th	Night	25% 7% 24% 32% 10% 3	360
	11th to 20th	Night	20% 6% 31% 33% 10% 1	354
	21st to end	Night	16% 3 32% 35% 14%	389
June	1st to 10th	Night	19% 5% 25% 41% 10% 1	360
	11th to 20th	Night	16% 6% 25% 40% 13% 1	360
	21st to end	Night	18% 4 25% 37% 16% 1	360
July	1st to 10th	Night	10% 3 23% 45% 19%	350
	11th to 20th	Night	11% 3 20% 45% 19% 1	348
	21st to end	Night	12% 2 20% 49% 15% 1	394
August	1st to 10th	Night	14% 3 19% 43% 21% 1	362
	11th to 20th	Night	14% 2 13% 40% 29% 2	565
	21st to end	Night	15% 4 20% 38% 21% 2	792
September	1st to 10th	Night	15% 4 19% 41% 20% 1	720
	11th to 20th	Night	17% 4 18% 34% 23% 3	720
	21st to end	Night	18% 5% 24% 29% 23% 2	720
October	1st to 10th	Night	24% 4 25% 30% 16% 2	720
	11th to 20th	Night	23% 6% 29% 30% 10% 1	720
	21st to end	Night	28% 9% 26% 30% 8%	792
November	1st to 10th	Night	26% 8% 26% 29% 11% 1	740
	11th to 20th	Night	23% 10% 33% 23% 10% 1	760
	21st to end	Night	26% 9% 30% 27% 8%	760
December	1st to 10th	Night	29% 8% 31% 26% 6% 1	760
	11th to 20th	Night	27% 10% 31% 25% 5% 1	760
	21st to end	Night	33% 8% 30% 24% 6%	836

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