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 2024-01-14.

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% 3 5% 5% 3 5% 5% 6% 7% 41%	74856
	Night	14% 5% 2 5% 5% 3 4 4 5% 7% 45%	74917
Transparency	Day	41% 4 11% 21% 18% 4	74579
	Night	39% 4 10% 21% 20% 5%	74713
Seeing	Day	17% 9% 21% 23% 20% 10%	13556
	Night	16% 8% 21% 29% 21% 4	23637

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	20% 7% 3 4 3 3 4 5% 4 6% 41%	1706
	11th to 20th	Day	23% 8% 3 5% 4 2 3 4 4 5% 40%	1647
	21st to end	Day	18% 5% 2 5% 5% 3 4 3 5% 6% 45%	1940
February	1st to 10th	Day	20% 9% 3 4 4 3 4 4 4 7% 38%	1800
	11th to 20th	Day	24% 6% 3 5% 5% 3 4 3 4 5% 38%	1748
	21st to end	Day	23% 8% 3 6% 4 2 4 3 4 5% 38%	1480
March	1st to 10th	Day	16% 5% 2 5% 4 3 6% 4 5% 6% 42%	1800
	11th to 20th	Day	22% 7% 3 5% 6% 3 5% 4 5% 6% 35%	1953
	21st to end	Day	15% 7% 3 6% 5% 3 4 5% 6% 7% 37%	2185
April	1st to 10th	Day	14% 6% 2 4 5% 3 4 5% 6% 8% 44%	2160
	11th to 20th	Day	14% 6% 3 5% 5% 4 4 5% 4 6% 46%	2134
	21st to end	Day	11% 4 2 5% 5% 4 5% 5% 6% 7% 47%	2222
May	1st to 10th	Day	12% 5% 2 5% 4 4 4 4 6% 7% 48%	2340
	11th to 20th	Day	13% 6% 2 6% 5% 4 5% 4 6% 7% 42%	2301
	21st to end	Day	11% 5% 2 5% 5% 4 5% 6% 7% 9% 41%	2531
June	1st to 10th	Day	11% 7% 3 6% 6% 4 6% 7% 8% 9% 35%	2340
	11th to 20th	Day	6% 4 2 5% 5% 4 6% 7% 8% 10% 44%	2340
	21st to end	Day	8% 5% 3 6% 5% 4 6% 7% 8% 10% 38%	2340
July	1st to 10th	Day	9% 6% 3 7% 6% 4 9% 7% 8% 10% 31%	2340
	11th to 20th	Day	9% 6% 2 5% 6% 5% 7% 9% 8% 12% 30%	2340
	21st to end	Day	7% 6% 3 6% 7% 5% 7% 8% 9% 11% 31%	2547
August	1st to 10th	Day	8% 4 2 5% 7% 5% 7% 8% 10% 11% 32%	2245
	11th to 20th	Day	10% 5% 3 7% 7% 4 6% 7% 9% 11% 32%	2125
	21st to end	Day	14% 6% 2 6% 7% 4 6% 6% 7% 8% 33%	2376
September	1st to 10th	Day	11% 7% 2 5% 5% 3 6% 6% 7% 9% 39%	2065
	11th to 20th	Day	15% 5% 2 5% 5% 4 5% 5% 6% 6% 42%	1980
	21st to end	Day	13% 5% 2 4 4 2 4 4 5% 6% 50%	1980
October	1st to 10th	Day	12% 5% 3 5% 4 3 3 3 4 5% 54%	1980
	11th to 20th	Day	11% 6% 2 4 4 2 4 3 4 6% 54%	1958
	21st to end	Day	15% 4 2 4 3 3 4 4 3 5% 53%	1874
November	1st to 10th	Day	13% 5% 2 3 4 2 5% 3 4 5% 55%	1672
	11th to 20th	Day	14% 4 2 5% 4 3 4 4 4 6% 51%	1710
	21st to end	Day	18% 5% 2 4 4 2 4 4 5% 6% 45%	1710
December	1st to 10th	Day	24% 7% 2 5% 3 3 4 4 4 6% 37%	1710
	11th to 20th	Day	19% 6% 3 5% 5% 3 4 5% 4 5% 41%	2153
	21st to end	Day	21% 8% 3 6% 5% 3 4 4 5% 6% 34%	3124
January	1st to 10th	Night	20% 6% 3 5% 4 2 4 4 3 5% 43%	2459
	11th to 20th	Night	19% 8% 3 5% 5% 3 5% 4 5% 6% 37%	2391
	21st to end	Night	17% 7% 3 5% 4 3 3 3 3 6% 46%	2412
February	1st to 10th	Night	19% 7% 3 5% 4 2 4 4 4 7% 42%	2160
	11th to 20th	Night	21% 5% 4 5% 5% 3 4 3 4 6% 42%	2098
	21st to end	Night	23% 6% 2 6% 4 3 4 4 5% 7% 35%	1776
March	1st to 10th	Night	16% 6% 2 5% 4 2 5% 4 5% 6% 45%	2160
	11th to 20th	Night	17% 6% 2 6% 5% 3 4 4 6% 6% 41%	2006
	21st to end	Night	15% 7% 3 5% 5% 3 4 5% 4 6% 43%	2178
April	1st to 10th	Night	12% 4 2 4 3 3 5% 5% 5% 8% 49%	1807
	11th to 20th	Night	15% 5% 2 4 4 2 3 4 4 7% 51%	1775
	21st to end	Night	10% 4 3 4 6% 2 4 4 5% 7% 53%	1737
May	1st to 10th	Night	10% 4 2 4 4 3 4 5% 5% 8% 51%	1620
	11th to 20th	Night	11% 5% 3 4 5% 3 6% 5% 7% 9% 43%	1592
	21st to end	Night	9% 5% 3 4 5% 3 5% 6% 5% 9% 46%	1744
June	1st to 10th	Night	8% 5% 2 6% 5% 4 6% 6% 8% 10% 40%	1620
	11th to 20th	Night	3 3 2 4 5% 3 5% 5% 6% 12% 53%	1620
	21st to end	Night	6% 4 2 4 5% 3 7% 6% 6% 12% 45%	1620
July	1st to 10th	Night	7% 5% 2 5% 6% 4 6% 5% 8% 12% 39%	1620
	11th to 20th	Night	6% 4 2 4 6% 4 5% 7% 7% 13% 41%	1620
	21st to end	Night	7% 5% 3 5% 5% 4 6% 6% 9% 11% 38%	1771
August	1st to 10th	Night	6% 5% 3 5% 5% 2 6% 6% 8% 12% 43%	1689
	11th to 20th	Night	11% 6% 3 5% 5% 3 6% 6% 6% 10% 40%	1776
	21st to end	Night	14% 5% 2 5% 5% 3 5% 5% 7% 8% 41%	1980
September	1st to 10th	Night	9% 5% 2 5% 7% 4 4 6% 7% 9% 44%	1876
	11th to 20th	Night	13% 5% 2 5% 6% 3 4 5% 5% 8% 43%	1980
	21st to end	Night	11% 5% 2 4 4 3 4 4 4 7% 54%	1980
October	1st to 10th	Night	11% 4 2 4 3 1 2 3 4 6% 60%	1980
	11th to 20th	Night	13% 5% 2 4 4 2 4 3 4 5% 54%	2002
	21st to end	Night	13% 5% 2 4 4 2 4 3 4 6% 53%	2478
November	1st to 10th	Night	13% 3 2 4 3 2 3 4 4 5% 55%	2406
	11th to 20th	Night	13% 5% 2 4 4 2 2 4 4 5% 54%	2470
	21st to end	Night	17% 6% 2 4 4 2 4 5% 5% 6% 46%	2470
December	1st to 10th	Night	21% 7% 3 6% 4 3 4 4 5% 5% 38%	2470
	11th to 20th	Night	18% 6% 2 5% 4 2 3 3 3 6% 48%	3042
	21st to end	Night	21% 6% 3 6% 5% 3 4 4 6% 8% 32%	4532

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	46% 3 7% 20% 20% 4	1707
	11th to 20th	Day	48% 3 7% 20% 19% 4	1647
	21st to end	Day	41% 3 6% 24% 21% 5%	1940
February	1st to 10th	Day	48% 3 7% 21% 19% 3	1800
	11th to 20th	Day	51% 2 5% 21% 18% 5%	1758
	21st to end	Day	50% 2 7% 15% 20% 6%	1480
March	1st to 10th	Day	43% 4 7% 16% 22% 8%	1800
	11th to 20th	Day	51% 4 9% 15% 17% 4	1953
	21st to end	Day	45% 4 10% 24% 14% 2	2185
April	1st to 10th	Day	38% 3 11% 23% 19% 6%	2160
	11th to 20th	Day	40% 3 7% 20% 24% 7%	2134
	21st to end	Day	35% 3 11% 29% 20% 3	2222
May	1st to 10th	Day	36% 3 12% 27% 18% 4	2340
	11th to 20th	Day	41% 4 16% 23% 14% 1	2305
	21st to end	Day	38% 5% 14% 27% 14% 3	2531
June	1st to 10th	Day	43% 6% 15% 21% 14% 1	2340
	11th to 20th	Day	33% 6% 19% 26% 15% 2	2340
	21st to end	Day	39% 7% 16% 22% 12% 3	2340
July	1st to 10th	Day	43% 8% 18% 20% 10% 2	2275
	11th to 20th	Day	41% 9% 21% 18% 9% 2	2271
	21st to end	Day	42% 8% 21% 20% 9%	2405
August	1st to 10th	Day	39% 8% 22% 24% 7% 1	2232
	11th to 20th	Day	42% 7% 17% 21% 11% 1	2125
	21st to end	Day	46% 6% 16% 17% 11% 4	2376
September	1st to 10th	Day	40% 5% 16% 18% 15% 6%	2065
	11th to 20th	Day	42% 4 11% 22% 18% 3	1980
	21st to end	Day	35% 4 10% 20% 23% 8%	1980
October	1st to 10th	Day	34% 4 7% 19% 27% 9%	1980
	11th to 20th	Day	32% 3 8% 23% 25% 9%	1958
	21st to end	Day	35% 2 5% 20% 29% 9%	1874
November	1st to 10th	Day	33% 3 6% 19% 30% 10%	1672
	11th to 20th	Day	36% 3 6% 20% 26% 9%	1710
	21st to end	Day	40% 3 7% 20% 24% 6%	1710
December	1st to 10th	Day	49% 3 6% 18% 19% 5%	1710
	11th to 20th	Day	48% 2 5% 20% 20% 6%	2150
	21st to end	Day	51% 2 7% 21% 17% 2	3124
January	1st to 10th	Night	45% 3 7% 21% 20% 4	2459
	11th to 20th	Night	48% 3 8% 19% 18% 4	2391
	21st to end	Night	43% 2 5% 23% 23% 5%	2412
February	1st to 10th	Night	43% 2 7% 21% 21% 5%	2160
	11th to 20th	Night	47% 2 6% 20% 18% 7%	2099
	21st to end	Night	50% 3 6% 16% 18% 7%	1776
March	1st to 10th	Night	41% 3 6% 17% 22% 10%	2160
	11th to 20th	Night	44% 4 11% 18% 19% 5%	2006
	21st to end	Night	43% 3 8% 25% 19% 3	2178
April	1st to 10th	Night	34% 3 13% 23% 21% 6%	1807
	11th to 20th	Night	35% 3 6% 22% 22% 11%	1775
	21st to end	Night	33% 3 9% 29% 20% 4	1737
May	1st to 10th	Night	31% 4 12% 23% 26% 4	1620
	11th to 20th	Night	36% 6% 18% 23% 16% 1	1593
	21st to end	Night	35% 6% 14% 24% 18% 3	1745
June	1st to 10th	Night	38% 6% 16% 23% 15% 2	1620
	11th to 20th	Night	25% 5% 23% 27% 17% 3	1620
	21st to end	Night	31% 7% 20% 23% 16% 5%	1620
July	1st to 10th	Night	36% 7% 19% 22% 12% 3	1575
	11th to 20th	Night	31% 9% 25% 20% 12% 4	1566
	21st to end	Night	36% 8% 19% 24% 10% 2	1672
August	1st to 10th	Night	32% 7% 23% 26% 11% 1	1678
	11th to 20th	Night	39% 7% 20% 17% 15% 2	1776
	21st to end	Night	40% 7% 16% 20% 13% 3	1980
September	1st to 10th	Night	37% 5% 17% 20% 16% 5%	1876
	11th to 20th	Night	38% 6% 12% 19% 22% 3	1980
	21st to end	Night	32% 4 9% 22% 24% 9%	1980
October	1st to 10th	Night	28% 4 8% 25% 27% 10%	1980
	11th to 20th	Night	35% 2 6% 23% 23% 11%	2002
	21st to end	Night	34% 2 4 20% 29% 10%	2478
November	1st to 10th	Night	32% 3 7% 20% 26% 12%	2406
	11th to 20th	Night	34% 2 5% 20% 28% 11%	2470
	21st to end	Night	40% 3 6% 22% 23% 7%	2470
December	1st to 10th	Night	49% 2 8% 19% 19% 4	2470
	11th to 20th	Night	40% 2 6% 20% 28% 5%	3044
	21st to end	Night	51% 2 6% 22% 17% 2	4532

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% 23% 34% 13% 3	270
	11th to 20th	Day	29% 19% 32% 14% 5% 2	249
	21st to end	Day	21% 22% 39% 13% 5%	264
February	1st to 10th	Day	28% 19% 32% 17% 3	240
	11th to 20th	Day	40% 18% 32% 10%	240
	21st to end	Day	32% 18% 38% 10% 2 1	198
March	1st to 10th	Day	24% 15% 38% 20% 2 2	240
	11th to 20th	Day	25% 18% 30% 19% 7% 1	393
	21st to end	Day	20% 17% 33% 22% 8%	462
April	1st to 10th	Day	20% 14% 27% 21% 16% 2	420
	11th to 20th	Day	17% 13% 30% 25% 14% 1	412
	21st to end	Day	15% 11% 27% 25% 16% 4	420
May	1st to 10th	Day	16% 9% 28% 25% 17% 5%	423
	11th to 20th	Day	14% 5% 18% 29% 22% 12%	447
	21st to end	Day	15% 3 11% 27% 26% 18%	485
June	1st to 10th	Day	15% 3 14% 28% 25% 15%	450
	11th to 20th	Day	7% 3 14% 26% 26% 24%	450
	21st to end	Day	12% 3 11% 27% 27% 20%	450
July	1st to 10th	Day	10% 2 8% 23% 32% 25%	445
	11th to 20th	Day	10% 2 8% 20% 32% 28%	444
	21st to end	Day	8% 3 9% 18% 34% 28%	488
August	1st to 10th	Day	11% 4 8% 23% 33% 22%	446
	11th to 20th	Day	13% 2 5% 31% 32% 18%	439
	21st to end	Day	17% 3 5% 26% 27% 21%	495
September	1st to 10th	Day	12% 5% 8% 23% 33% 18%	450
	11th to 20th	Day	16% 3 12% 23% 33% 14%	450
	21st to end	Day	14% 3 13% 28% 31% 11%	450
October	1st to 10th	Day	14% 3 21% 30% 22% 10%	450
	11th to 20th	Day	13% 8% 25% 30% 21% 2	450
	21st to end	Day	18% 11% 21% 32% 16% 3	389
November	1st to 10th	Day	21% 9% 25% 29% 13% 3	270
	11th to 20th	Day	18% 14% 36% 24% 8%	270
	21st to end	Day	17% 14% 36% 22% 9% 2	270
December	1st to 10th	Day	29% 15% 32% 18% 5% 1	270
	11th to 20th	Day	25% 16% 32% 20% 6% 1	270
	21st to end	Day	32% 15% 30% 16% 6%	297
January	1st to 10th	Night	25% 15% 33% 22% 6%	760
	11th to 20th	Night	22% 16% 26% 29% 7%	736
	21st to end	Night	23% 12% 36% 26% 3	792
February	1st to 10th	Night	22% 12% 31% 31% 4	720
	11th to 20th	Night	25% 16% 32% 26% 2	703
	21st to end	Night	25% 13% 35% 24% 2	592
March	1st to 10th	Night	19% 14% 33% 31% 4	720
	11th to 20th	Night	19% 13% 31% 27% 9% 1	720
	21st to end	Night	19% 14% 25% 31% 11%	792
April	1st to 10th	Night	13% 11% 29% 30% 16% 1	547
	11th to 20th	Night	18% 9% 27% 30% 15% 1	533
	21st to end	Night	12% 5% 25% 37% 19% 1	540
May	1st to 10th	Night	11% 6% 22% 35% 24% 2	540
	11th to 20th	Night	13% 5% 16% 34% 26% 6%	531
	21st to end	Night	12% 1 9% 32% 39% 7%	584
June	1st to 10th	Night	9% 2 9% 37% 36% 6%	540
	11th to 20th	Night	4 2 10% 31% 38% 16%	540
	21st to end	Night	7% 2 8% 30% 43% 10%	540
July	1st to 10th	Night	8% 2 6% 21% 47% 17%	525
	11th to 20th	Night	8% 2 5% 21% 46% 19%	522
	21st to end	Night	9% 2 6% 23% 45% 15%	591
August	1st to 10th	Night	7% 1 5% 25% 48% 15%	537
	11th to 20th	Night	14% 2 7% 26% 42% 9%	534
	21st to end	Night	16% 3 6% 24% 41% 10%	594
September	1st to 10th	Night	10% 2 7% 31% 39% 12%	616
	11th to 20th	Night	14% 3 12% 28% 38% 6%	720
	21st to end	Night	13% 3 15% 30% 35% 3	720
October	1st to 10th	Night	12% 3 19% 34% 24% 7%	720
	11th to 20th	Night	15% 7% 23% 33% 21% 2	720
	21st to end	Night	16% 7% 22% 34% 18% 3	792
November	1st to 10th	Night	13% 7% 23% 34% 21% 2	740
	11th to 20th	Night	15% 9% 31% 31% 13% 1	760
	21st to end	Night	20% 10% 25% 33% 11% 1	760
December	1st to 10th	Night	25% 12% 26% 27% 9% 1	760
	11th to 20th	Night	23% 10% 30% 27% 9%	760
	21st to end	Night	28% 11% 26% 28% 7%	836

Page generated at 2024-01-11 12:32:00. Version ac07

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