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 2026-04-02.

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	16% 10% 3 8% 5% 5% 5% 4 5% 7% 32%	131561
	Night	17% 12% 4 9% 5% 5% 4 3 5% 6% 30%	130264
Transparency	Day	52% 4 12% 22% 9% 1	135013
	Night	55% 4 11% 20% 10% 1	134899
Seeing	Day	21% 8% 28% 25% 13% 5%	16186
	Night	22% 7% 27% 32% 11% 1	25386

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% 16% 6% 15% 6% 5% 4 3 5% 5% 21%	4661
	11th to 20th	Day	12% 17% 7% 14% 7% 6% 5% 4 5% 5% 20%	4650
	21st to end	Day	9% 14% 6% 13% 9% 8% 6% 4 5% 5% 20%	5281
February	1st to 10th	Day	14% 16% 4 11% 7% 4 4 4 5% 5% 25%	1890
	11th to 20th	Day	14% 13% 5% 11% 7% 4 4 4 6% 6% 26%	1877
	21st to end	Day	18% 14% 4 9% 6% 5% 5% 4 5% 5% 25%	1730
March	1st to 10th	Day	17% 11% 4 10% 6% 5% 5% 3 6% 6% 25%	4576
	11th to 20th	Day	12% 13% 4 8% 5% 5% 6% 4 5% 7% 30%	5029
	21st to end	Day	18% 10% 3 8% 5% 4 4 3 4 5% 36%	5952
April	1st to 10th	Day	21% 11% 3 7% 5% 4 4 3 4 6% 33%	2412
	11th to 20th	Day	21% 9% 3 7% 4 4 4 3 4 6% 36%	2374
	21st to end	Day	22% 9% 3 7% 5% 4 5% 3 5% 5% 32%	2528
May	1st to 10th	Day	24% 11% 4 8% 5% 4 5% 4 5% 6% 25%	6346
	11th to 20th	Day	17% 9% 3 9% 6% 5% 5% 3 5% 6% 31%	6318
	21st to end	Day	21% 8% 2 7% 5% 4 4 4 5% 6% 33%	6949
June	1st to 10th	Day	22% 8% 2 7% 5% 5% 4 3 5% 7% 30%	2800
	11th to 20th	Day	13% 6% 2 6% 5% 5% 5% 4 7% 8% 39%	2800
	21st to end	Day	19% 8% 2 6% 5% 5% 4 5% 7% 8% 32%	2800
July	1st to 10th	Day	13% 7% 3 7% 5% 6% 6% 5% 6% 9% 34%	6360
	11th to 20th	Day	11% 6% 2 7% 4 5% 5% 4 6% 9% 42%	6360
	21st to end	Day	10% 5% 2 5% 4 4 5% 4 7% 10% 45%	6926
August	1st to 10th	Day	14% 7% 3 8% 5% 5% 5% 4 5% 8% 36%	4540
	11th to 20th	Day	16% 6% 2 6% 4 4 4 4 7% 9% 39%	4080
	21st to end	Day	16% 5% 2 6% 4 4 4 4 6% 9% 39%	4312
September	1st to 10th	Day	12% 5% 1 7% 5% 4 5% 4 6% 8% 43%	2400
	11th to 20th	Day	13% 4 2 5% 4 3 4 3 5% 8% 49%	2380
	21st to end	Day	17% 6% 2 6% 4 4 4 4 5% 7% 40%	2168
October	1st to 10th	Day	18% 8% 2 6% 4 5% 4 3 5% 6% 38%	2000
	11th to 20th	Day	19% 9% 3 8% 5% 5% 5% 4 6% 6% 30%	2000
	21st to end	Day	25% 10% 3 6% 4 6% 5% 4 4 5% 28%	2015
November	1st to 10th	Day	16% 9% 4 7% 5% 5% 5% 5% 6% 6% 32%	1851
	11th to 20th	Day	18% 12% 3 8% 6% 4 5% 4 5% 7% 29%	1722
	21st to end	Day	21% 14% 5% 8% 5% 6% 5% 4 5% 5% 22%	1680
December	1st to 10th	Day	20% 19% 5% 11% 5% 5% 5% 5% 5% 6% 14%	2680
	11th to 20th	Day	18% 15% 5% 10% 6% 4 4 4 5% 5% 24%	3066
	21st to end	Day	22% 15% 4 12% 5% 5% 5% 3 4 4 21%	4048
January	1st to 10th	Night	13% 18% 7% 16% 6% 4 4 2 4 5% 21%	8234
	11th to 20th	Night	12% 16% 7% 15% 8% 6% 5% 4 5% 5% 18%	8235
	21st to end	Night	12% 16% 5% 12% 6% 6% 5% 4 5% 6% 22%	8895
February	1st to 10th	Night	14% 14% 5% 11% 7% 6% 6% 3 5% 5% 24%	2730
	11th to 20th	Night	14% 13% 4 12% 7% 5% 4 4 5% 5% 28%	2627
	21st to end	Night	15% 15% 4 8% 7% 4 4 3 4 6% 29%	2076
March	1st to 10th	Night	21% 14% 4 8% 5% 5% 4 2 4 4 29%	5484
	11th to 20th	Night	13% 12% 4 8% 6% 5% 4 3 6% 7% 30%	5147
	21st to end	Night	18% 11% 3 8% 5% 4 4 3 4 5% 33%	5221
April	1st to 10th	Night	22% 10% 3 7% 6% 4 4 4 4 6% 32%	2011
	11th to 20th	Night	20% 9% 3 7% 5% 4 4 4 4 5% 35%	1975
	21st to end	Night	21% 9% 3 7% 4 4 3 3 5% 6% 34%	1887
May	1st to 10th	Night	24% 9% 3 9% 5% 5% 5% 4 6% 7% 23%	3594
	11th to 20th	Night	17% 8% 2 7% 4 4 5% 4 5% 7% 37%	3575
	21st to end	Night	16% 10% 3 8% 5% 5% 5% 4 6% 7% 31%	3926
June	1st to 10th	Night	16% 7% 2 8% 5% 6% 6% 5% 6% 8% 31%	1600
	11th to 20th	Night	15% 6% 3 6% 4 4 4 4 6% 7% 41%	1600
	21st to end	Night	18% 7% 2 7% 4 4 4 4 6% 8% 35%	1600
July	1st to 10th	Night	14% 7% 2 8% 4 5% 6% 4 7% 9% 33%	3600
	11th to 20th	Night	12% 6% 2 6% 4 4 5% 4 6% 7% 43%	3600
	21st to end	Night	9% 6% 2 7% 4 4 5% 4 6% 7% 45%	3926
August	1st to 10th	Night	12% 8% 2 6% 5% 5% 3 4 6% 8% 40%	2605
	11th to 20th	Night	14% 6% 2 7% 4 4 4 4 7% 7% 42%	2936
	21st to end	Night	12% 6% 3 7% 5% 4 5% 4 6% 8% 41%	3586
September	1st to 10th	Night	11% 5% 2 6% 5% 4 5% 3 5% 7% 46%	2000
	11th to 20th	Night	13% 5% 2 4 3 3 3 3 5% 7% 51%	2020
	21st to end	Night	16% 6% 3 6% 4 4 4 4 4 6% 44%	2230
October	1st to 10th	Night	18% 6% 2 6% 4 4 4 3 5% 7% 39%	2400
	11th to 20th	Night	19% 8% 3 8% 5% 5% 4 4 5% 7% 33%	2400
	21st to end	Night	22% 9% 3 8% 5% 5% 4 3 4 7% 29%	2825
November	1st to 10th	Night	19% 11% 3 7% 5% 4 4 3 5% 6% 33%	2667
	11th to 20th	Night	18% 9% 4 8% 6% 4 5% 3 5% 5% 32%	2894
	21st to end	Night	21% 13% 4 10% 5% 4 4 4 4 6% 25%	2940
December	1st to 10th	Night	18% 17% 4 12% 7% 6% 5% 4 5% 6% 17%	4720
	11th to 20th	Night	23% 14% 4 9% 5% 4 4 3 4 4 25%	5348
	21st to end	Night	26% 17% 4 10% 4 4 4 3 4 4 20%	7150

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	65% 3 12% 15% 4 1	4662
	11th to 20th	Day	66% 3 9% 12% 9% 1	4680
	21st to end	Day	65% 3 11% 11% 8% 1	5281
February	1st to 10th	Day	59% 4 9% 21% 5% 1	1890
	11th to 20th	Day	57% 4 13% 18% 7% 1	1886
	21st to end	Day	61% 3 11% 14% 10% 1	1730
March	1st to 10th	Day	58% 4 10% 15% 11% 3	4579
	11th to 20th	Day	53% 4 17% 17% 9% 1	5029
	21st to end	Day	50% 4 7% 20% 16% 2	5952
April	1st to 10th	Day	53% 4 7% 20% 13% 3	2412
	11th to 20th	Day	50% 4 8% 22% 15% 2	2374
	21st to end	Day	55% 4 9% 16% 14% 3	2528
May	1st to 10th	Day	59% 4 8% 19% 8% 2	6357
	11th to 20th	Day	54% 4 13% 19% 9% 1	6322
	21st to end	Day	51% 4 13% 21% 10% 1	6949
June	1st to 10th	Day	53% 5% 11% 19% 11% 1	2800
	11th to 20th	Day	41% 6% 13% 25% 12% 2	2800
	21st to end	Day	48% 6% 14% 22% 10% 1	2800
July	1st to 10th	Day	47% 2 14% 27% 9%	6290
	11th to 20th	Day	39% 3 14% 31% 13%	6285
	21st to end	Day	35% 4 14% 38% 9%	6728
August	1st to 10th	Day	46% 4 16% 24% 9%	4526
	11th to 20th	Day	42% 4 16% 30% 8% 1	4119
	21st to end	Day	42% 4 17% 26% 11%	4312
September	1st to 10th	Day	37% 5% 15% 31% 12%	2400
	11th to 20th	Day	35% 4 12% 34% 14% 1	2380
	21st to end	Day	43% 5% 15% 27% 11%	2168
October	1st to 10th	Day	46% 3 10% 31% 9%	3260
	11th to 20th	Day	47% 3 15% 27% 7% 1	3240
	21st to end	Day	49% 3 17% 24% 7%	3227
November	1st to 10th	Day	50% 6% 13% 23% 7% 1	1851
	11th to 20th	Day	55% 4 13% 17% 10%	1722
	21st to end	Day	63% 6% 13% 12% 6%	1680
December	1st to 10th	Day	71% 3 12% 12% 1	2680
	11th to 20th	Day	63% 5% 10% 16% 7%	3066
	21st to end	Day	68% 3 8% 17% 5%	4048
January	1st to 10th	Night	68% 2 11% 13% 5%	8234
	11th to 20th	Night	70% 3 9% 11% 6%	8280
	21st to end	Night	64% 3 7% 14% 11% 1	8895
February	1st to 10th	Night	62% 4 10% 17% 7% 1	2730
	11th to 20th	Night	58% 4 10% 20% 8%	2629
	21st to end	Night	58% 4 9% 19% 10% 1	2076
March	1st to 10th	Night	59% 3 6% 15% 12% 3	5494
	11th to 20th	Night	53% 3 16% 16% 8% 3	5148
	21st to end	Night	53% 3 6% 23% 13% 2	5221
April	1st to 10th	Night	54% 4 8% 18% 13% 2	2011
	11th to 20th	Night	51% 4 8% 20% 15% 1	1975
	21st to end	Night	50% 4 9% 18% 16% 3	1887
May	1st to 10th	Night	59% 5% 9% 17% 8% 3	3600
	11th to 20th	Night	47% 5% 14% 19% 14% 1	3576
	21st to end	Night	51% 5% 12% 18% 13% 1	3927
June	1st to 10th	Night	48% 7% 12% 20% 12% 1	1600
	11th to 20th	Night	41% 5% 13% 22% 17% 2	1600
	21st to end	Night	46% 6% 13% 20% 14% 1	1600
July	1st to 10th	Night	47% 3 17% 21% 11% 1	3560
	11th to 20th	Night	39% 3 14% 32% 12%	3552
	21st to end	Night	38% 4 12% 30% 15%	3809
August	1st to 10th	Night	43% 4 16% 26% 10%	2595
	11th to 20th	Night	42% 3 16% 31% 8%	2963
	21st to end	Night	41% 3 16% 26% 12% 2	3586
September	1st to 10th	Night	38% 6% 12% 29% 15% 1	2000
	11th to 20th	Night	34% 5% 13% 35% 13%	2020
	21st to end	Night	41% 5% 13% 28% 13%	2230
October	1st to 10th	Night	42% 3 13% 31% 11% 1	3920
	11th to 20th	Night	44% 3 15% 29% 9%	3899
	21st to end	Night	49% 4 15% 22% 9%	4563
November	1st to 10th	Night	52% 3 14% 22% 8% 1	2667
	11th to 20th	Night	54% 4 12% 18% 10% 1	2894
	21st to end	Night	61% 4 13% 17% 5%	2940
December	1st to 10th	Night	69% 3 12% 13% 3	4720
	11th to 20th	Night	64% 3 8% 15% 10% 1	5348
	21st to end	Night	69% 3 7% 13% 9%	7150

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% 8% 30% 27% 9% 1	220
	11th to 20th	Day	26% 9% 33% 23% 7% 1	220
	21st to end	Day	16% 7% 35% 32% 8% 1	270
February	1st to 10th	Day	27% 11% 34% 20% 8%	330
	11th to 20th	Day	21% 12% 37% 26% 4	364
	21st to end	Day	27% 7% 31% 31% 4	446
March	1st to 10th	Day	21% 9% 32% 29% 8%	540
	11th to 20th	Day	21% 12% 34% 25% 7%	540
	21st to end	Day	26% 9% 33% 21% 9% 3	594
April	1st to 10th	Day	25% 12% 31% 22% 9% 1	504
	11th to 20th	Day	27% 14% 27% 17% 11% 4	492
	21st to end	Day	28% 10% 30% 19% 10% 3	500
May	1st to 10th	Day	26% 7% 28% 25% 10% 3	503
	11th to 20th	Day	16% 9% 31% 26% 11% 6%	527
	21st to end	Day	20% 7% 29% 24% 16% 4	573
June	1st to 10th	Day	24% 8% 25% 28% 11% 4	530
	11th to 20th	Day	15% 9% 28% 25% 18% 5%	530
	21st to end	Day	22% 8% 25% 27% 13% 5%	530
July	1st to 10th	Day	15% 4 22% 33% 19% 7%	525
	11th to 20th	Day	13% 5% 28% 29% 19% 6%	524
	21st to end	Day	13% 5% 26% 31% 20% 6%	576
August	1st to 10th	Day	14% 3 17% 36% 24% 6%	526
	11th to 20th	Day	15% 3 18% 26% 26% 12%	519
	21st to end	Day	15% 6% 22% 27% 20% 10%	583
September	1st to 10th	Day	13% 7% 23% 25% 18% 13%	530
	11th to 20th	Day	12% 3 19% 24% 26% 17%	530
	21st to end	Day	19% 6% 25% 24% 18% 7%	530
October	1st to 10th	Day	22% 7% 25% 22% 17% 7%	530
	11th to 20th	Day	21% 11% 33% 23% 10% 3	530
	21st to end	Day	31% 9% 24% 27% 9%	481
November	1st to 10th	Day	24% 14% 28% 24% 10% 1	425
	11th to 20th	Day	25% 8% 36% 21% 6% 3	262
	21st to end	Day	28% 13% 31% 20% 6% 2	220
December	1st to 10th	Day	27% 10% 29% 26% 7% 1	220
	11th to 20th	Day	25% 15% 36% 19% 4 1	220
	21st to end	Day	31% 8% 31% 19% 8% 2	242
January	1st to 10th	Night	26% 8% 31% 30% 5%	840
	11th to 20th	Night	26% 10% 29% 29% 5% 1	840
	21st to end	Night	21% 6% 30% 34% 9% 1	924
February	1st to 10th	Night	21% 6% 35% 30% 7%	840
	11th to 20th	Night	20% 10% 35% 29% 5%	823
	21st to end	Night	23% 8% 33% 32% 5%	692
March	1st to 10th	Night	23% 9% 33% 29% 6%	840
	11th to 20th	Night	24% 10% 32% 29% 5%	840
	21st to end	Night	24% 10% 27% 30% 9%	924
April	1st to 10th	Night	26% 9% 30% 30% 5%	805
	11th to 20th	Night	23% 10% 31% 26% 9%	791
	21st to end	Night	26% 7% 27% 29% 10% 1	687
May	1st to 10th	Night	25% 6% 25% 32% 10% 2	400
	11th to 20th	Night	20% 6% 30% 34% 10% 1	394
	21st to end	Night	16% 3 32% 36% 13%	433
June	1st to 10th	Night	18% 5% 25% 42% 11% 1	400
	11th to 20th	Night	16% 6% 26% 40% 12% 1	400
	21st to end	Night	19% 4 25% 37% 14% 1	400
July	1st to 10th	Night	10% 4 22% 46% 18%	390
	11th to 20th	Night	12% 3 19% 47% 19% 1	388
	21st to end	Night	13% 2 20% 49% 16% 1	438
August	1st to 10th	Night	13% 3 17% 44% 22% 1	404
	11th to 20th	Night	15% 2 13% 39% 29% 2	629
	21st to end	Night	15% 4 19% 39% 21% 2	880
September	1st to 10th	Night	14% 4 20% 41% 20% 1	800
	11th to 20th	Night	16% 4 17% 34% 26% 4	800
	21st to end	Night	18% 4 23% 30% 23% 2	800
October	1st to 10th	Night	23% 4 24% 32% 17% 2	800
	11th to 20th	Night	22% 6% 29% 32% 10% 1	800
	21st to end	Night	28% 8% 26% 30% 9%	880
November	1st to 10th	Night	26% 9% 25% 29% 10% 1	820
	11th to 20th	Night	23% 10% 34% 24% 9% 1	840
	21st to end	Night	26% 9% 31% 26% 8%	840
December	1st to 10th	Night	28% 8% 31% 27% 6% 1	840
	11th to 20th	Night	27% 10% 32% 25% 5% 1	840
	21st to end	Night	32% 8% 29% 24% 6%	924

Page generated at 2026-03-30 02:18:43. Version ac07

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