Little River Canyon National Preserve
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little River Canyon National Preserve clear sky chart from 2005-11-06 to 2026-02-01.

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	14% 6% 2 6% 4 4 5% 4 6% 7% 40%	127258
	Night	15% 6% 2 6% 4 4 4 3 5% 7% 44%	124800
Transparency	Day	41% 4 11% 22% 18% 5%	131022
	Night	39% 4 10% 22% 20% 6%	129106
Seeing	Day	18% 9% 22% 24% 18% 9%	16259
	Night	17% 8% 22% 29% 20% 4	26313

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	19% 9% 5% 5% 2 3 3 3 4 4 44%	4146
	11th to 20th	Day	15% 6% 4 6% 3 3 3 2 3 4 51%	4150
	21st to end	Day	23% 8% 2 6% 4 3 3 2 4 6% 39%	4970
February	1st to 10th	Day	19% 10% 3 4 4 4 3 3 5% 7% 38%	2000
	11th to 20th	Day	24% 7% 2 5% 5% 4 3 2 5% 4 38%	1948
	21st to end	Day	22% 8% 3 6% 4 3 4 2 4 5% 39%	1650
March	1st to 10th	Day	20% 8% 3 7% 5% 5% 5% 4 5% 5% 33%	4480
	11th to 20th	Day	14% 7% 2 4 4 3 4 3 5% 6% 47%	4925
	21st to end	Day	16% 6% 3 7% 4 4 4 3 5% 6% 42%	5497
April	1st to 10th	Day	14% 6% 2 6% 4 4 5% 4 6% 7% 43%	2400
	11th to 20th	Day	13% 6% 3 5% 4 5% 4 4 4 6% 47%	2374
	21st to end	Day	11% 4 1 6% 4 5% 5% 4 7% 7% 45%	2470
May	1st to 10th	Day	17% 7% 2 6% 4 5% 5% 4 7% 8% 35%	5862
	11th to 20th	Day	19% 8% 2 8% 5% 5% 5% 4 7% 8% 30%	5861
	21st to end	Day	16% 6% 2 6% 4 4 4 4 6% 8% 39%	6433
June	1st to 10th	Day	11% 7% 2 7% 5% 6% 6% 5% 8% 9% 35%	2600
	11th to 20th	Day	6% 4 2 6% 5% 5% 6% 6% 8% 10% 42%	2600
	21st to end	Day	8% 5% 2 7% 5% 6% 6% 5% 9% 10% 38%	2600
July	1st to 10th	Day	8% 5% 2 7% 5% 6% 7% 6% 8% 11% 36%	5900
	11th to 20th	Day	7% 5% 2 6% 6% 7% 7% 7% 9% 13% 32%	5900
	21st to end	Day	12% 8% 3 9% 7% 7% 7% 6% 8% 11% 22%	6424
August	1st to 10th	Day	6% 3 2 5% 4 5% 6% 6% 8% 11% 46%	4077
	11th to 20th	Day	7% 4 2 7% 4 4 6% 5% 8% 11% 42%	3849
	21st to end	Day	8% 4 2 5% 4 4 5% 4 6% 7% 51%	4312
September	1st to 10th	Day	11% 7% 2 5% 4 4 5% 5% 7% 9% 40%	2293
	11th to 20th	Day	15% 4 2 6% 4 5% 5% 4 6% 7% 42%	2200
	21st to end	Day	13% 6% 2 5% 3 3 4 4 6% 7% 48%	2200
October	1st to 10th	Day	11% 5% 2 5% 4 4 3 3 4 5% 54%	2200
	11th to 20th	Day	10% 5% 1 5% 3 3 4 3 4 6% 57%	2175
	21st to end	Day	15% 5% 2 4 3 4 3 3 3 5% 54%	2082
November	1st to 10th	Day	13% 6% 2 4 3 3 5% 2 4 5% 53%	1852
	11th to 20th	Day	14% 4 2 5% 3 3 4 3 4 6% 51%	1890
	21st to end	Day	18% 6% 1 5% 3 3 4 4 5% 6% 46%	1890
December	1st to 10th	Day	21% 6% 2 5% 4 3 3 3 4 5% 43%	3020
	11th to 20th	Day	20% 9% 3 7% 3 4 4 3 4 4 38%	3463
	21st to end	Day	21% 7% 3 6% 4 4 3 3 4 7% 37%	4565
January	1st to 10th	Night	16% 9% 3 6% 3 3 4 3 4 5% 44%	6019
	11th to 20th	Night	17% 7% 3 6% 3 3 3 2 4 5% 47%	6030
	21st to end	Night	20% 9% 2 4 3 3 3 3 4 5% 44%	6210
February	1st to 10th	Night	18% 7% 2 6% 4 3 3 3 4 6% 43%	2401
	11th to 20th	Night	22% 7% 3 6% 4 3 3 3 3 5% 40%	2338
	21st to end	Night	21% 7% 2 6% 3 4 4 3 5% 6% 38%	1980
March	1st to 10th	Night	24% 9% 2 7% 4 4 4 3 4 6% 32%	5373
	11th to 20th	Night	12% 5% 1 5% 3 3 4 3 6% 7% 49%	5034
	21st to end	Night	16% 7% 3 6% 4 4 4 3 4 5% 43%	5467
April	1st to 10th	Night	12% 4 2 5% 3 4 4 4 6% 8% 48%	2007
	11th to 20th	Night	14% 5% 2 5% 3 3 3 3 5% 7% 50%	1975
	21st to end	Night	10% 4 3 5% 5% 3 4 3 5% 6% 51%	1929
May	1st to 10th	Night	13% 7% 3 7% 5% 5% 5% 5% 7% 8% 35%	4033
	11th to 20th	Night	21% 7% 3 7% 5% 5% 5% 4 6% 7% 30%	4032
	21st to end	Night	13% 6% 2 6% 4 4 4 4 6% 10% 41%	4421
June	1st to 10th	Night	8% 5% 2 7% 4 6% 5% 5% 7% 10% 40%	1800
	11th to 20th	Night	5% 3 2 5% 5% 4 4 4 6% 12% 51%	1800
	21st to end	Night	6% 5% 1 5% 4 5% 6% 5% 7% 11% 46%	1800
July	1st to 10th	Night	6% 5% 2 7% 6% 5% 6% 5% 8% 12% 38%	4058
	11th to 20th	Night	7% 4 2 6% 5% 5% 5% 5% 8% 14% 41%	4057
	21st to end	Night	10% 7% 3 8% 5% 5% 6% 5% 8% 11% 30%	4427
August	1st to 10th	Night	5% 4 2 4 3 3 5% 4 8% 11% 51%	3068
	11th to 20th	Night	8% 5% 2 5% 3 4 4 4 6% 9% 50%	3200
	21st to end	Night	9% 4 2 4 3 3 4 3 5% 7% 56%	3586
September	1st to 10th	Night	9% 5% 2 6% 6% 5% 5% 4 6% 8% 44%	2085
	11th to 20th	Night	13% 5% 2 6% 5% 4 4 4 5% 8% 43%	2200
	21st to end	Night	12% 4 2 5% 4 4 4 3 5% 7% 51%	2200
October	1st to 10th	Night	11% 4 2 5% 3 2 3 2 4 6% 59%	2200
	11th to 20th	Night	12% 5% 2 5% 3 3 3 3 4 4 57%	2225
	21st to end	Night	13% 5% 2 5% 3 3 3 2 4 6% 54%	2754
November	1st to 10th	Night	13% 4 2 5% 3 3 3 3 4 5% 54%	2666
	11th to 20th	Night	13% 6% 2 4 3 3 3 3 4 5% 54%	2730
	21st to end	Night	16% 7% 2 5% 3 3 3 4 5% 6% 46%	2730
December	1st to 10th	Night	20% 6% 2 5% 3 3 3 3 4 5% 46%	4380
	11th to 20th	Night	20% 8% 2 6% 4 3 3 2 3 5% 43%	4952
	21st to end	Night	22% 6% 3 6% 4 4 4 3 5% 6% 37%	6633

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	45% 2 4 23% 23% 3	4147
	11th to 20th	Day	39% 2 5% 24% 27% 4	4150
	21st to end	Day	48% 2 6% 19% 20% 5%	4970
February	1st to 10th	Day	47% 3 7% 21% 19% 3	2000
	11th to 20th	Day	51% 2 4 20% 18% 5%	1958
	21st to end	Day	49% 2 6% 16% 21% 6%	1650
March	1st to 10th	Day	52% 3 7% 13% 17% 8%	4480
	11th to 20th	Day	38% 3 5% 19% 23% 13%	4925
	21st to end	Day	44% 2 9% 25% 18% 3	5499
April	1st to 10th	Day	39% 4 11% 23% 19% 6%	2400
	11th to 20th	Day	38% 3 7% 21% 24% 7%	2374
	21st to end	Day	36% 3 11% 28% 19% 3	2470
May	1st to 10th	Day	46% 4 15% 23% 11% 2	5897
	11th to 20th	Day	51% 4 15% 21% 9%	5865
	21st to end	Day	44% 4 10% 24% 17% 2	6447
June	1st to 10th	Day	43% 5% 16% 22% 13% 1	2600
	11th to 20th	Day	33% 6% 18% 25% 15% 2	2600
	21st to end	Day	38% 8% 16% 23% 13% 3	2600
July	1st to 10th	Day	38% 9% 20% 23% 10% 1	5835
	11th to 20th	Day	38% 10% 30% 18% 4 1	5831
	21st to end	Day	52% 9% 19% 16% 4	6240
August	1st to 10th	Day	28% 7% 14% 37% 14% 1	4064
	11th to 20th	Day	33% 7% 17% 27% 14% 3	3885
	21st to end	Day	31% 5% 14% 24% 23% 3	4311
September	1st to 10th	Day	39% 5% 16% 18% 16% 6%	2293
	11th to 20th	Day	41% 5% 11% 23% 17% 3	2200
	21st to end	Day	36% 4 12% 20% 21% 7%	2200
October	1st to 10th	Day	25% 4 4 14% 39% 14%	3590
	11th to 20th	Day	22% 2 5% 19% 30% 23%	3519
	21st to end	Day	27% 3 6% 24% 30% 11%	3345
November	1st to 10th	Day	35% 3 6% 19% 28% 9%	1852
	11th to 20th	Day	35% 3 7% 21% 26% 9%	1890
	21st to end	Day	39% 4 7% 21% 24% 6%	1890
December	1st to 10th	Day	44% 3 5% 18% 26% 5%	3020
	11th to 20th	Day	51% 2 6% 20% 16% 5%	3460
	21st to end	Day	49% 2 7% 27% 15% 2	4565
January	1st to 10th	Night	44% 2 5% 25% 21% 4	6019
	11th to 20th	Night	41% 2 4 22% 24% 6%	6030
	21st to end	Night	45% 1 4 20% 24% 7%	6210
February	1st to 10th	Night	44% 2 6% 21% 22% 5%	2401
	11th to 20th	Night	49% 2 6% 19% 18% 7%	2339
	21st to end	Night	47% 3 6% 17% 20% 7%	1980
March	1st to 10th	Night	54% 2 6% 14% 19% 5%	5373
	11th to 20th	Night	34% 2 7% 18% 23% 15%	5034
	21st to end	Night	45% 2 5% 23% 19% 5%	5467
April	1st to 10th	Night	34% 3 13% 22% 21% 6%	2007
	11th to 20th	Night	35% 3 6% 23% 23% 11%	1975
	21st to end	Night	35% 3 10% 28% 20% 4	1929
May	1st to 10th	Night	46% 4 15% 19% 13% 1	4060
	11th to 20th	Night	53% 4 14% 21% 8% 1	4033
	21st to end	Night	40% 4 13% 25% 17% 2	4429
June	1st to 10th	Night	38% 5% 15% 23% 16% 2	1800
	11th to 20th	Night	27% 5% 22% 26% 18% 3	1800
	21st to end	Night	31% 7% 19% 23% 16% 5%	1800
July	1st to 10th	Night	36% 9% 20% 23% 10% 1	4015
	11th to 20th	Night	31% 9% 31% 21% 5% 1	4006
	21st to end	Night	46% 10% 22% 18% 4 1	4297
August	1st to 10th	Night	25% 6% 15% 39% 14% 1	3057
	11th to 20th	Night	31% 6% 17% 27% 17% 2	3230
	21st to end	Night	27% 5% 14% 20% 29% 4	3586
September	1st to 10th	Night	38% 5% 16% 19% 16% 6%	2085
	11th to 20th	Night	38% 6% 11% 21% 21% 3	2200
	21st to end	Night	33% 5% 10% 22% 22% 8%	2200
October	1st to 10th	Night	22% 5% 6% 18% 34% 16%	3590
	11th to 20th	Night	20% 1 3 19% 31% 26%	3620
	21st to end	Night	25% 2 4 26% 31% 13%	4441
November	1st to 10th	Night	33% 3 8% 20% 25% 11%	2666
	11th to 20th	Night	33% 2 5% 21% 28% 11%	2730
	21st to end	Night	39% 3 6% 22% 23% 7%	2730
December	1st to 10th	Night	42% 2 5% 20% 27% 4	4380
	11th to 20th	Night	46% 3 5% 19% 24% 4	4954
	21st to end	Night	48% 2 6% 27% 15% 1	6633

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	28% 23% 33% 13% 3	330
	11th to 20th	Day	28% 22% 32% 13% 4 2	330
	21st to end	Day	25% 22% 37% 12% 4	363
February	1st to 10th	Day	27% 18% 32% 18% 5%	300
	11th to 20th	Day	40% 17% 31% 10% 2	300
	21st to end	Day	29% 22% 38% 10% 1	249
March	1st to 10th	Day	27% 18% 33% 18% 3 1	300
	11th to 20th	Day	25% 18% 29% 20% 7% 1	471
	21st to end	Day	20% 17% 35% 21% 7%	550
April	1st to 10th	Day	22% 14% 30% 19% 14% 2	500
	11th to 20th	Day	16% 13% 33% 24% 12% 1	492
	21st to end	Day	15% 12% 28% 27% 15% 4	500
May	1st to 10th	Day	17% 10% 27% 26% 15% 5%	503
	11th to 20th	Day	15% 7% 20% 29% 19% 10%	527
	21st to end	Day	16% 6% 14% 26% 23% 15%	573
June	1st to 10th	Day	15% 4 16% 28% 24% 13%	530
	11th to 20th	Day	7% 3 16% 28% 24% 22%	530
	21st to end	Day	11% 3 10% 28% 28% 19%	530
July	1st to 10th	Day	10% 3 8% 26% 32% 22%	525
	11th to 20th	Day	10% 2 7% 22% 32% 27%	524
	21st to end	Day	10% 3 9% 19% 34% 25%	576
August	1st to 10th	Day	13% 4 9% 25% 31% 19%	526
	11th to 20th	Day	13% 2 7% 31% 30% 17%	519
	21st to end	Day	16% 4 7% 27% 27% 20%	583
September	1st to 10th	Day	12% 5% 12% 26% 29% 15%	530
	11th to 20th	Day	16% 2 12% 25% 32% 13%	530
	21st to end	Day	15% 4 15% 28% 29% 9%	530
October	1st to 10th	Day	12% 4 23% 32% 21% 9%	530
	11th to 20th	Day	12% 8% 25% 32% 21% 2	530
	21st to end	Day	18% 11% 22% 31% 16% 2	465
November	1st to 10th	Day	23% 9% 26% 29% 11% 2	330
	11th to 20th	Day	17% 15% 37% 23% 8%	330
	21st to end	Day	19% 16% 35% 21% 8% 2	330
December	1st to 10th	Day	30% 16% 33% 16% 5% 1	330
	11th to 20th	Day	26% 17% 31% 20% 6% 1	330
	21st to end	Day	31% 16% 31% 16% 6%	363
January	1st to 10th	Night	25% 15% 33% 22% 5%	840
	11th to 20th	Night	22% 17% 28% 27% 6%	840
	21st to end	Night	23% 13% 36% 25% 3	924
February	1st to 10th	Night	22% 12% 31% 31% 4	801
	11th to 20th	Night	27% 16% 30% 25% 2	783
	21st to end	Night	23% 15% 35% 25% 2	660
March	1st to 10th	Night	20% 14% 32% 29% 4	800
	11th to 20th	Night	19% 13% 31% 28% 9% 1	800
	21st to end	Night	19% 13% 26% 31% 10%	880
April	1st to 10th	Night	14% 12% 29% 29% 15%	607
	11th to 20th	Night	17% 10% 27% 31% 14% 1	593
	21st to end	Night	13% 6% 24% 37% 19% 1	600
May	1st to 10th	Night	11% 6% 23% 35% 23% 2	600
	11th to 20th	Night	15% 5% 18% 33% 24% 6%	591
	21st to end	Night	13% 2 11% 33% 35% 6%	650
June	1st to 10th	Night	10% 3 10% 37% 34% 6%	600
	11th to 20th	Night	5% 2 10% 31% 38% 14%	600
	21st to end	Night	7% 3 8% 29% 43% 11%	600
July	1st to 10th	Night	8% 2 6% 23% 46% 15%	585
	11th to 20th	Night	8% 2 5% 20% 46% 19%	582
	21st to end	Night	9% 3 6% 23% 44% 14%	657
August	1st to 10th	Night	9% 2 5% 27% 44% 14%	597
	11th to 20th	Night	13% 3 9% 25% 41% 9%	594
	21st to end	Night	15% 3 8% 25% 40% 9%	660
September	1st to 10th	Night	10% 2 10% 31% 36% 10%	685
	11th to 20th	Night	15% 3 11% 29% 38% 5%	800
	21st to end	Night	14% 3 15% 30% 35% 3	800
October	1st to 10th	Night	12% 3 21% 34% 24% 6%	800
	11th to 20th	Night	14% 7% 23% 35% 20% 2	800
	21st to end	Night	16% 7% 23% 34% 18% 2	880
November	1st to 10th	Night	14% 7% 23% 34% 19% 2	820
	11th to 20th	Night	15% 9% 31% 31% 13% 1	840
	21st to end	Night	19% 12% 26% 31% 11%	840
December	1st to 10th	Night	25% 13% 27% 27% 8% 1	840
	11th to 20th	Night	23% 10% 30% 27% 9%	840
	21st to end	Night	28% 12% 26% 28% 6%	924

Page generated at 2026-01-29 00:21:44. Version ac07

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