Loup Canal
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Loup Canal clear sky chart from 2005-11-06 to 2026-01-17.

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	11% 7% 2 7% 4 4 4 3 5% 7% 46%	127376
	Night	9% 6% 2 6% 4 4 4 3 5% 7% 49%	124508
Transparency	Day	37% 4 13% 26% 17% 3	130998
	Night	35% 4 12% 27% 19% 3	128953
Seeing	Day	14% 9% 31% 30% 14% 3	17421
	Night	12% 9% 34% 34% 10%	27400

By Month

Percentage Cloud Cover SE (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	9% 12% 5% 14% 7% 5% 6% 4 4 5% 28%	3820
	11th to 20th	Day	6% 9% 4 9% 5% 4 6% 4 4 6% 41%	4134
	21st to end	Day	6% 7% 4 11% 5% 4 4 4 5% 6% 45%	4488
February	1st to 10th	Day	9% 13% 4 9% 6% 4 4 2 4 7% 37%	1800
	11th to 20th	Day	8% 10% 3 7% 5% 4 5% 3 5% 8% 42%	1868
	21st to end	Day	8% 10% 2 6% 4 3 4 4 6% 6% 47%	1650
March	1st to 10th	Day	13% 8% 2 6% 3 3 3 2 3 4 54%	4713
	11th to 20th	Day	10% 7% 2 5% 3 3 4 3 4 6% 53%	4980
	21st to end	Day	19% 10% 3 9% 4 4 5% 4 6% 7% 29%	5462
April	1st to 10th	Day	13% 8% 3 6% 4 3 3 3 5% 7% 44%	2230
	11th to 20th	Day	15% 8% 3 6% 5% 3 4 4 4 6% 43%	2563
	21st to end	Day	19% 8% 2 6% 4 3 4 3 5% 6% 39%	2600
May	1st to 10th	Day	12% 6% 2 6% 4 4 4 3 5% 7% 48%	5862
	11th to 20th	Day	13% 5% 2 5% 3 3 3 3 4 6% 51%	5862
	21st to end	Day	19% 6% 3 7% 4 4 4 4 5% 6% 38%	6434
June	1st to 10th	Day	7% 4 2 5% 4 4 4 4 7% 9% 50%	2635
	11th to 20th	Day	10% 5% 2 4 5% 4 4 4 6% 9% 48%	2962
	21st to end	Day	7% 4 1 5% 4 4 4 4 7% 9% 52%	2800
July	1st to 10th	Day	11% 4 2 5% 4 4 4 4 6% 9% 48%	6340
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 6% 8% 49%	6039
	21st to end	Day	6% 4 2 5% 4 5% 5% 5% 6% 9% 48%	6422
August	1st to 10th	Day	6% 5% 2 6% 5% 5% 6% 4 6% 9% 45%	4234
	11th to 20th	Day	15% 6% 2 6% 4 4 4 4 6% 7% 41%	4171
	21st to end	Day	7% 5% 2 6% 4 4 4 3 5% 7% 54%	4675
September	1st to 10th	Day	13% 5% 2 5% 3 3 4 3 4 6% 53%	2243
	11th to 20th	Day	10% 4 2 5% 3 3 3 3 4 7% 56%	2200
	21st to end	Day	10% 4 1 3 3 3 3 3 5% 7% 59%	2200
October	1st to 10th	Day	14% 6% 2 4 3 3 3 3 3 5% 53%	2113
	11th to 20th	Day	10% 5% 1 4 3 3 3 2 5% 5% 59%	2000
	21st to end	Day	16% 6% 3 5% 3 3 2 3 5% 5% 50%	2120
November	1st to 10th	Day	9% 5% 2 5% 4 3 3 3 5% 8% 54%	1853
	11th to 20th	Day	9% 6% 2 6% 4 4 3 3 6% 6% 52%	1890
	21st to end	Day	12% 8% 2 6% 4 3 4 3 5% 7% 46%	1769
December	1st to 10th	Day	5% 4 2 6% 5% 4 4 3 5% 6% 55%	2690
	11th to 20th	Day	7% 9% 3 9% 5% 4 4 4 6% 7% 42%	3088
	21st to end	Day	13% 10% 3 11% 4 4 4 3 4 6% 37%	4466
January	1st to 10th	Night	9% 11% 4 14% 7% 5% 5% 5% 6% 6% 28%	6337
	11th to 20th	Night	4 8% 3 7% 5% 5% 7% 4 6% 6% 45%	5979
	21st to end	Night	5% 8% 4 11% 5% 4 5% 3 4 6% 44%	6490
February	1st to 10th	Night	10% 11% 3 8% 6% 4 4 4 4 5% 41%	2600
	11th to 20th	Night	8% 8% 3 8% 5% 4 5% 5% 5% 7% 42%	2435
	21st to end	Night	7% 6% 3 7% 4 5% 4 3 5% 7% 50%	1980
March	1st to 10th	Night	12% 6% 2 5% 3 3 3 3 4 6% 54%	5150
	11th to 20th	Night	10% 6% 2 5% 2 3 3 3 4 6% 56%	4980
	21st to end	Night	14% 8% 2 6% 5% 5% 4 4 6% 9% 37%	5467
April	1st to 10th	Night	13% 7% 2 6% 4 4 4 4 5% 6% 46%	2168
	11th to 20th	Night	12% 7% 3 6% 5% 4 4 3 5% 7% 45%	1786
	21st to end	Night	16% 6% 2 6% 4 4 4 3 5% 6% 46%	1800
May	1st to 10th	Night	13% 5% 2 5% 3 3 3 3 5% 6% 50%	4053
	11th to 20th	Night	11% 4 2 5% 3 3 3 4 5% 6% 53%	4053
	21st to end	Night	16% 7% 2 6% 4 4 4 4 5% 7% 42%	4443
June	1st to 10th	Night	6% 4 2 4 3 4 4 4 6% 8% 55%	1751
	11th to 20th	Night	6% 6% 2 5% 4 4 4 3 5% 9% 53%	1415
	21st to end	Night	5% 3 1 4 4 4 5% 3 6% 8% 58%	1600
July	1st to 10th	Night	8% 4 2 5% 3 3 3 3 5% 7% 57%	3638
	11th to 20th	Night	8% 4 2 6% 4 4 5% 4 6% 9% 49%	3935
	21st to end	Night	5% 4 1 4 3 3 4 4 6% 10% 56%	4449
August	1st to 10th	Night	4 3 1 5% 3 4 4 4 7% 11% 53%	2926
	11th to 20th	Night	12% 5% 2 5% 4 3 4 3 6% 7% 50%	2888
	21st to end	Night	5% 3 2 5% 4 4 4 4 5% 9% 54%	3234
September	1st to 10th	Night	9% 3 1 4 2 3 3 3 5% 6% 61%	2150
	11th to 20th	Night	8% 4 1 4 3 4 3 3 5% 7% 59%	2200
	21st to end	Night	9% 3 1 4 4 3 3 3 5% 6% 60%	2200
October	1st to 10th	Night	14% 5% 2 5% 3 2 3 3 5% 7% 52%	2266
	11th to 20th	Night	11% 5% 2 4 3 2 3 2 4 5% 59%	2400
	21st to end	Night	15% 5% 2 4 2 3 3 3 4 6% 54%	2717
November	1st to 10th	Night	7% 5% 2 4 3 3 3 3 5% 6% 58%	2665
	11th to 20th	Night	9% 6% 1 5% 4 3 3 3 4 7% 54%	2730
	21st to end	Night	10% 7% 2 5% 4 3 3 3 5% 6% 52%	2846
December	1st to 10th	Night	4 5% 2 5% 4 4 4 3 5% 8% 56%	4720
	11th to 20th	Night	9% 6% 3 7% 4 3 3 3 6% 8% 48%	5339
	21st to end	Night	14% 11% 3 10% 4 4 4 3 4 5% 38%	6718

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	58% 4 10% 18% 8% 1	3821
	11th to 20th	Day	44% 3 14% 18% 18% 2	4134
	21st to end	Day	41% 4 14% 25% 16% 1	4488
February	1st to 10th	Day	48% 4 14% 21% 11% 2	1800
	11th to 20th	Day	42% 5% 12% 22% 16% 3	1877
	21st to end	Day	37% 5% 13% 25% 16% 4	1650
March	1st to 10th	Day	36% 3 8% 26% 22% 5%	4713
	11th to 20th	Day	34% 3 7% 25% 25% 5%	4980
	21st to end	Day	53% 4 19% 17% 5% 2	5464
April	1st to 10th	Day	39% 5% 12% 27% 14% 2	2230
	11th to 20th	Day	42% 4 13% 24% 15% 3	2563
	21st to end	Day	46% 5% 11% 24% 14% 1	2600
May	1st to 10th	Day	36% 4 11% 26% 21% 2	5900
	11th to 20th	Day	35% 4 11% 22% 19% 8%	5866
	21st to end	Day	46% 5% 9% 26% 13% 1	6447
June	1st to 10th	Day	29% 6% 18% 32% 12% 2	2635
	11th to 20th	Day	31% 6% 15% 28% 17% 2	2962
	21st to end	Day	28% 6% 15% 31% 16% 4	2800
July	1st to 10th	Day	35% 3 12% 33% 16% 1	6271
	11th to 20th	Day	34% 3 13% 32% 15% 2	5966
	21st to end	Day	32% 4 19% 27% 17% 3	6240
August	1st to 10th	Day	36% 5% 14% 27% 14% 3	4220
	11th to 20th	Day	41% 4 14% 25% 15% 1	4210
	21st to end	Day	31% 4 13% 26% 20% 6%	4674
September	1st to 10th	Day	33% 4 12% 27% 20% 5%	2243
	11th to 20th	Day	29% 4 14% 33% 18% 2	2200
	21st to end	Day	26% 3 9% 33% 27% 2	2200
October	1st to 10th	Day	22% 2 5% 21% 43% 6%	3438
	11th to 20th	Day	23% 2 13% 33% 23% 8%	3240
	21st to end	Day	34% 2 11% 29% 22% 3	3413
November	1st to 10th	Day	30% 3 14% 28% 21% 3	1853
	11th to 20th	Day	32% 4 13% 27% 22% 2	1890
	21st to end	Day	39% 4 12% 28% 15% 2	1769
December	1st to 10th	Day	32% 2 17% 29% 19% 2	2690
	11th to 20th	Day	41% 3 19% 25% 11% 1	3085
	21st to end	Day	49% 4 10% 26% 10% 1	4466
January	1st to 10th	Night	54% 5% 10% 19% 12% 1	6337
	11th to 20th	Night	40% 4 12% 25% 16% 2	5979
	21st to end	Night	41% 4 10% 23% 19% 2	6490
February	1st to 10th	Night	45% 4 13% 22% 14% 2	2600
	11th to 20th	Night	40% 5% 13% 23% 14% 3	2436
	21st to end	Night	33% 4 11% 26% 21% 5%	1980
March	1st to 10th	Night	33% 3 7% 29% 24% 4	5150
	11th to 20th	Night	30% 3 6% 23% 31% 7%	4980
	21st to end	Night	45% 4 18% 26% 6% 1	5467
April	1st to 10th	Night	38% 5% 11% 26% 18% 2	2168
	11th to 20th	Night	38% 5% 11% 25% 17% 3	1786
	21st to end	Night	39% 6% 12% 25% 17% 1	1800
May	1st to 10th	Night	35% 4 9% 28% 23% 1	4080
	11th to 20th	Night	32% 4 14% 20% 23% 8%	4054
	21st to end	Night	42% 4 12% 24% 16% 2	4452
June	1st to 10th	Night	27% 6% 17% 31% 16% 3	1751
	11th to 20th	Night	28% 5% 15% 28% 19% 5%	1415
	21st to end	Night	25% 4 17% 31% 20% 3	1600
July	1st to 10th	Night	29% 2 13% 39% 15% 2	3600
	11th to 20th	Night	33% 5% 13% 30% 17% 2	3888
	21st to end	Night	25% 4 20% 28% 21% 2	4320
August	1st to 10th	Night	25% 5% 16% 34% 15% 4	2916
	11th to 20th	Night	34% 4 17% 29% 15% 1	2915
	21st to end	Night	28% 4 14% 28% 19% 7%	3234
September	1st to 10th	Night	26% 4 11% 30% 22% 8%	2150
	11th to 20th	Night	24% 5% 12% 34% 22% 3	2200
	21st to end	Night	26% 4 8% 30% 27% 5%	2200
October	1st to 10th	Night	21% 3 6% 17% 48% 6%	3708
	11th to 20th	Night	23% 2 10% 31% 28% 7%	3899
	21st to end	Night	31% 2 9% 32% 23% 3	4378
November	1st to 10th	Night	26% 4 13% 28% 24% 4	2665
	11th to 20th	Night	31% 3 12% 29% 21% 4	2730
	21st to end	Night	34% 3 13% 28% 18% 3	2846
December	1st to 10th	Night	28% 3 16% 34% 18% 1	4720
	11th to 20th	Night	36% 3 15% 32% 14%	5341
	21st to end	Night	50% 4 10% 26% 9% 1	6718

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	15% 13% 35% 25% 10% 2	330
	11th to 20th	Day	17% 18% 32% 28% 5%	318
	21st to end	Day	15% 6% 47% 24% 8% 1	330
February	1st to 10th	Day	16% 16% 38% 27% 3	300
	11th to 20th	Day	14% 14% 41% 21% 9% 1	300
	21st to end	Day	14% 16% 43% 22% 4 1	249
March	1st to 10th	Day	15% 16% 42% 20% 6% 1	300
	11th to 20th	Day	23% 11% 36% 22% 7% 1	300
	21st to end	Day	29% 14% 35% 16% 4 1	330
April	1st to 10th	Day	20% 22% 36% 17% 4	330
	11th to 20th	Day	19% 16% 37% 22% 6%	681
	21st to end	Day	24% 16% 30% 21% 9% 1	700
May	1st to 10th	Day	17% 11% 33% 26% 10% 2	703
	11th to 20th	Day	19% 12% 29% 23% 14% 3	725
	21st to end	Day	18% 9% 29% 31% 11% 3	789
June	1st to 10th	Day	7% 7% 26% 35% 21% 5%	730
	11th to 20th	Day	10% 6% 34% 32% 15% 3	730
	21st to end	Day	8% 6% 33% 35% 16% 2	730
July	1st to 10th	Day	10% 3 18% 35% 28% 6%	721
	11th to 20th	Day	6% 3 21% 43% 22% 5%	718
	21st to end	Day	8% 2 18% 44% 23% 4	794
August	1st to 10th	Day	8% 3 21% 42% 23% 3	726
	11th to 20th	Day	10% 4 19% 41% 23% 4	715
	21st to end	Day	10% 3 24% 36% 23% 4	803
September	1st to 10th	Day	15% 4 26% 35% 16% 4	373
	11th to 20th	Day	8% 5% 36% 30% 16% 6%	330
	21st to end	Day	16% 5% 30% 28% 14% 6%	330
October	1st to 10th	Day	19% 8% 28% 27% 14% 4	330
	11th to 20th	Day	15% 11% 42% 22% 9% 1	330
	21st to end	Day	22% 16% 33% 21% 8% 1	363
November	1st to 10th	Day	13% 17% 38% 22% 8% 2	330
	11th to 20th	Day	13% 15% 42% 23% 7%	330
	21st to end	Day	20% 15% 32% 22% 10% 2	330
December	1st to 10th	Day	11% 10% 45% 27% 6% 1	330
	11th to 20th	Day	15% 13% 39% 25% 8%	330
	21st to end	Day	19% 12% 40% 23% 6%	363
January	1st to 10th	Night	13% 12% 35% 32% 7% 1	1050
	11th to 20th	Night	12% 13% 39% 29% 6% 1	1031
	21st to end	Night	13% 8% 42% 31% 6%	1100
February	1st to 10th	Night	16% 12% 40% 29% 4	1000
	11th to 20th	Night	12% 11% 42% 30% 4	881
	21st to end	Night	10% 11% 47% 25% 6%	660
March	1st to 10th	Night	14% 13% 37% 31% 4 1	706
	11th to 20th	Night	17% 12% 37% 29% 6%	600
	21st to end	Night	19% 10% 41% 24% 5%	660
April	1st to 10th	Night	18% 13% 41% 25% 3	600
	11th to 20th	Night	15% 14% 39% 27% 4	593
	21st to end	Night	19% 10% 33% 31% 7%	600
May	1st to 10th	Night	16% 9% 36% 31% 10%	600
	11th to 20th	Night	13% 9% 33% 34% 11%	591
	21st to end	Night	16% 7% 32% 33% 12%	650
June	1st to 10th	Night	7% 3 25% 50% 14% 1	600
	11th to 20th	Night	8% 6% 33% 41% 12%	600
	21st to end	Night	6% 3 31% 47% 13%	600
July	1st to 10th	Night	8% 3 20% 42% 26% 1	585
	11th to 20th	Night	3 2 23% 49% 23% 1	582
	21st to end	Night	5% 2 17% 54% 21%	657
August	1st to 10th	Night	6% 2 19% 49% 23% 2	597
	11th to 20th	Night	7% 2 20% 48% 22% 1	594
	21st to end	Night	9% 1 27% 42% 20% 2	660
September	1st to 10th	Night	11% 3 24% 41% 19% 2	600
	11th to 20th	Night	9% 3 30% 42% 14% 1	600
	21st to end	Night	10% 5% 32% 36% 17% 1	600
October	1st to 10th	Night	17% 7% 31% 32% 12% 1	666
	11th to 20th	Night	13% 12% 38% 31% 6%	800
	21st to end	Night	17% 11% 31% 32% 9% 1	957
November	1st to 10th	Night	10% 10% 37% 36% 7% 1	1025
	11th to 20th	Night	12% 12% 40% 31% 6%	1050
	21st to end	Night	14% 11% 36% 29% 10%	1050
December	1st to 10th	Night	10% 12% 41% 30% 6%	1050
	11th to 20th	Night	15% 10% 38% 31% 7%	1050
	21st to end	Night	16% 12% 38% 29% 5%	1155

Page generated at 2026-01-14 00:14:26. Version ac07

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