LAAS -- Boy Scout Camp Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the LAAS -- Boy Scout Camp Road clear sky chart from 2005-11-06 to 2024-06-30.

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	2 4 1 4 3 3 3 3 4 6% 67%	89428
	Night	2 4 2 5% 3 3 3 3 4 6% 64%	89854
Transparency	Day	16% 4 6% 17% 31% 26%	89148
	Night	16% 4 6% 17% 31% 26%	89655
Seeing	Day	8% 11% 27% 33% 15% 5%	15042
	Night	6% 7% 18% 33% 29% 7%	24791

By Month

Percentage Cloud Cover SW (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	3 4 2 7% 3 3 3 3 5% 7% 59%	2543
	11th to 20th	Day	4 6% 2 6% 4 3 4 4 6% 10% 51%	2860
	21st to end	Day	5% 8% 3 8% 4 4 4 4 6% 8% 46%	3220
February	1st to 10th	Day	5% 8% 3 6% 3 2 4 3 4 5% 56%	1900
	11th to 20th	Day	4 7% 2 6% 3 3 3 3 6% 7% 55%	1850
	21st to end	Day	5% 8% 3 6% 4 3 4 2 4 5% 55%	1570
March	1st to 10th	Day	3 9% 3 8% 4 4 4 3 5% 7% 50%	3138
	11th to 20th	Day	2 7% 2 3 3 3 4 3 5% 9% 60%	3379
	21st to end	Day	2 8% 3 6% 4 4 5% 5% 7% 8% 48%	4124
April	1st to 10th	Day	4 6% 2 5% 3 3 3 3 5% 8% 57%	2280
	11th to 20th	Day	3 4 1 5% 3 2 3 3 4 6% 66%	2249
	21st to end	Day	3 3 1 3 2 2 3 3 5% 7% 69%	2280
May	1st to 10th	Day	2 2 1 2 2 2 2 2 3 5% 78%	3800
	11th to 20th	Day	1 2 2 1 2 2 3 3 6% 78%	4071
	21st to end	Day	2 2 1 2 1 2 2 2 3 4 80%	4500
June	1st to 10th	Day	1 3 1 3 2 2 2 3 5% 6% 72%	2660
	11th to 20th	Day	1 1 1 1 2 2 3 4 85%	2660
	21st to end	Day	1 1 1 1 1 2 2 3 4 85%	2647
July	1st to 10th	Day	1 1 1 1 2 2 3 4 4 80%	2520
	11th to 20th	Day	2 2 1 3 2 2 2 3 5% 5% 74%	2483
	21st to end	Day	2 2 1 2 2 2 3 3 4 6% 72%	2470
August	1st to 10th	Day	1 2 1 2 2 2 2 2 3 4 78%	2149
	11th to 20th	Day	1 1 1 1 1 2 2 3 5% 83%	2122
	21st to end	Day	1 1 1 2 2 2 2 2 3 4 80%	2376
September	1st to 10th	Day	1 1 2 1 2 3 2 4 4 80%	2160
	11th to 20th	Day	1 1 1 1 1 2 1 3 3 86%	2080
	21st to end	Day	1 2 1 2 2 2 2 2 3 3 82%	1980
October	1st to 10th	Day	3 3 1 3 2 2 3 2 3 5% 73%	1945
	11th to 20th	Day	1 2 1 3 1 3 3 2 2 5% 78%	1800
	21st to end	Day	1 3 1 3 2 2 3 3 4 6% 74%	1980
November	1st to 10th	Day	2 4 1 4 3 2 3 3 5% 6% 69%	1688
	11th to 20th	Day	2 4 1 4 3 3 4 4 5% 5% 66%	1710
	21st to end	Day	3 5% 2 6% 4 4 4 3 5% 6% 58%	1710
December	1st to 10th	Day	3 6% 2 6% 3 4 4 4 6% 7% 55%	1710
	11th to 20th	Day	6% 10% 2 7% 5% 4 5% 4 6% 8% 43%	2020
	21st to end	Day	5% 10% 3 9% 6% 5% 4 4 4 7% 42%	2794
January	1st to 10th	Night	3 6% 2 8% 3 4 4 3 5% 7% 55%	4397
	11th to 20th	Night	2 5% 3 9% 5% 4 4 4 6% 9% 50%	4110
	21st to end	Night	6% 7% 3 11% 4 4 4 4 5% 7% 46%	4445
February	1st to 10th	Night	4 7% 3 8% 4 3 3 3 4 6% 53%	2280
	11th to 20th	Night	4 6% 2 6% 4 3 4 4 5% 6% 57%	2218
	21st to end	Night	4 5% 3 8% 5% 3 4 3 5% 7% 54%	1884
March	1st to 10th	Night	2 6% 2 8% 4 4 5% 4 8% 10% 46%	3736
	11th to 20th	Night	1 4 2 5% 4 4 4 4 5% 8% 60%	3597
	21st to end	Night	3 7% 2 9% 4 4 5% 3 6% 9% 48%	3527
April	1st to 10th	Night	3 6% 3 6% 4 3 4 4 6% 7% 56%	1900
	11th to 20th	Night	2 4 1 5% 4 2 3 3 4 6% 66%	1879
	21st to end	Night	2 2 1 4 2 3 3 2 5% 8% 68%	1900
May	1st to 10th	Night	1 1 1 3 2 2 2 2 2 4 79%	3162
	11th to 20th	Night	1 1 1 2 1 1 2 2 4 5% 80%	2834
	21st to end	Night	1 1 2 1 1 1 1 2 3 85%	3080
June	1st to 10th	Night	1 2 1 2 2 2 2 2 5% 5% 76%	1520
	11th to 20th	Night	1 2 1 1 1 1 2 4 88%	1520
	21st to end	Night	1 1 1 1 1 1 1 2 3 90%	1512
July	1st to 10th	Night	1 1 1 1 2 2 2 3 4 83%	1440
	11th to 20th	Night	1 1 1 2 1 2 2 2 3 4 81%	1473
	21st to end	Night	1 2 1 2 1 2 2 2 3 3 80%	1845
August	1st to 10th	Night	2 1 1 2 1 1 2 2 3 4 82%	1790
	11th to 20th	Night	1 1 1 1 2 1 3 3 87%	1780
	21st to end	Night	1 1 1 1 1 1 1 1 2 3 87%	1980
September	1st to 10th	Night	1 1 2 1 1 1 1 2 3 87%	1800
	11th to 20th	Night	1 1 1 1 2 1 2 4 87%	1879
	21st to end	Night	2 1 2 2 2 3 4 84%	1980
October	1st to 10th	Night	1 2 1 2 2 3 4 2 4 5% 75%	2011
	11th to 20th	Night	1 2 1 3 2 2 3 3 4 6% 73%	2160
	21st to end	Night	1 2 1 3 2 2 2 3 4 5% 75%	2376
November	1st to 10th	Night	1 3 1 6% 3 3 3 3 5% 8% 64%	2388
	11th to 20th	Night	2 3 2 5% 3 3 3 4 5% 7% 64%	2470
	21st to end	Night	2 4 2 7% 4 4 4 3 6% 7% 57%	2470
December	1st to 10th	Night	4 5% 2 6% 5% 3 4 3 6% 8% 55%	2470
	11th to 20th	Night	6% 10% 4 8% 6% 4 5% 4 6% 7% 40%	3179
	21st to end	Night	6% 9% 2 8% 5% 5% 5% 5% 6% 8% 42%	4862

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	19% 5% 6% 27% 34% 10%	2543
	11th to 20th	Day	23% 6% 15% 15% 27% 13%	2860
	21st to end	Day	30% 5% 9% 19% 26% 11%	3220
February	1st to 10th	Day	26% 3 3 18% 27% 22%	1900
	11th to 20th	Day	22% 5% 5% 19% 30% 19%	1860
	21st to end	Day	28% 4 6% 19% 28% 14%	1570
March	1st to 10th	Day	29% 6% 8% 20% 24% 14%	3138
	11th to 20th	Day	19% 6% 10% 30% 22% 14%	3379
	21st to end	Day	27% 8% 10% 24% 25% 6%	4124
April	1st to 10th	Day	22% 5% 9% 25% 26% 13%	2280
	11th to 20th	Day	17% 4 7% 26% 32% 15%	2252
	21st to end	Day	12% 5% 8% 25% 39% 11%	2280
May	1st to 10th	Day	11% 3 6% 17% 39% 23%	3800
	11th to 20th	Day	8% 3 5% 20% 48% 16%	4074
	21st to end	Day	9% 2 5% 25% 41% 18%	4500
June	1st to 10th	Day	13% 4 6% 20% 33% 25%	2660
	11th to 20th	Day	5% 3 5% 14% 33% 40%	2660
	21st to end	Day	6% 2 2 7% 29% 54%	2647
July	1st to 10th	Day	7% 2 3 7% 23% 59%	2451
	11th to 20th	Day	11% 3 4 15% 30% 38%	2408
	21st to end	Day	11% 3 6% 17% 32% 31%	2333
August	1st to 10th	Day	10% 3 3 7% 27% 51%	2135
	11th to 20th	Day	6% 1 2 11% 31% 48%	2122
	21st to end	Day	9% 2 2 7% 34% 46%	2376
September	1st to 10th	Day	7% 3 3 8% 28% 50%	2160
	11th to 20th	Day	5% 2 2 11% 33% 47%	2080
	21st to end	Day	9% 2 2 11% 40% 36%	1980
October	1st to 10th	Day	13% 3 4 15% 26% 37%	1945
	11th to 20th	Day	11% 3 3 13% 34% 37%	1800
	21st to end	Day	12% 4 4 11% 31% 38%	1980
November	1st to 10th	Day	14% 3 3 18% 35% 27%	1688
	11th to 20th	Day	16% 4 5% 15% 31% 29%	1710
	21st to end	Day	23% 4 6% 14% 27% 27%	1710
December	1st to 10th	Day	25% 5% 6% 15% 28% 21%	1710
	11th to 20th	Day	35% 6% 6% 19% 21% 13%	2019
	21st to end	Day	36% 6% 6% 18% 23% 12%	2794
January	1st to 10th	Night	22% 5% 5% 18% 36% 15%	4397
	11th to 20th	Night	24% 7% 9% 20% 28% 12%	4110
	21st to end	Night	28% 5% 8% 18% 26% 15%	4445
February	1st to 10th	Night	24% 6% 5% 16% 25% 25%	2280
	11th to 20th	Night	20% 4 5% 19% 31% 20%	2219
	21st to end	Night	24% 6% 6% 19% 28% 17%	1884
March	1st to 10th	Night	24% 6% 11% 19% 25% 15%	3736
	11th to 20th	Night	16% 5% 9% 33% 23% 14%	3597
	21st to end	Night	22% 4 10% 24% 33% 7%	3527
April	1st to 10th	Night	21% 5% 9% 26% 26% 14%	1900
	11th to 20th	Night	13% 3 8% 25% 32% 18%	1879
	21st to end	Night	10% 4 9% 28% 38% 11%	1900
May	1st to 10th	Night	7% 3 8% 17% 35% 30%	3162
	11th to 20th	Night	7% 2 3 20% 45% 22%	2835
	21st to end	Night	6% 2 6% 23% 45% 18%	3080
June	1st to 10th	Night	10% 3 7% 21% 36% 23%	1520
	11th to 20th	Night	4 2 4 14% 33% 42%	1520
	21st to end	Night	3 1 2 7% 29% 58%	1512
July	1st to 10th	Night	7% 2 2 7% 24% 58%	1400
	11th to 20th	Night	7% 3 4 16% 30% 40%	1425
	21st to end	Night	9% 3 5% 18% 30% 35%	1742
August	1st to 10th	Night	7% 3 2 9% 29% 51%	1780
	11th to 20th	Night	5% 2 2 10% 31% 50%	1780
	21st to end	Night	6% 1 1 8% 33% 51%	1980
September	1st to 10th	Night	6% 2 2 8% 29% 54%	1800
	11th to 20th	Night	5% 2 2 11% 36% 45%	1879
	21st to end	Night	5% 2 2 13% 39% 40%	1980
October	1st to 10th	Night	11% 3 3 15% 30% 38%	2011
	11th to 20th	Night	11% 3 3 15% 31% 38%	2160
	21st to end	Night	10% 3 5% 10% 33% 40%	2376
November	1st to 10th	Night	13% 4 4 15% 35% 28%	2388
	11th to 20th	Night	15% 4 5% 14% 29% 33%	2470
	21st to end	Night	20% 4 6% 17% 25% 28%	2470
December	1st to 10th	Night	23% 5% 6% 13% 27% 26%	2470
	11th to 20th	Night	38% 5% 7% 14% 22% 15%	3179
	21st to end	Night	31% 7% 5% 18% 26% 12%	4862

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	19% 19% 31% 22% 8% 1	184
	11th to 20th	Day	18% 18% 30% 26% 7% 1	370
	21st to end	Day	17% 23% 32% 18% 8% 2	430
February	1st to 10th	Day	15% 17% 35% 23% 8% 3	460
	11th to 20th	Day	19% 18% 31% 23% 8% 2	455
	21st to end	Day	17% 20% 34% 23% 6% 1	382
March	1st to 10th	Day	16% 23% 33% 22% 5% 1	460
	11th to 20th	Day	16% 20% 31% 25% 7% 1	460
	21st to end	Day	16% 22% 33% 23% 6%	506
April	1st to 10th	Day	15% 14% 33% 25% 12% 1	460
	11th to 20th	Day	14% 16% 32% 26% 10% 1	452
	21st to end	Day	8% 15% 30% 27% 14% 5%	460
May	1st to 10th	Day	12% 14% 33% 26% 13% 2	463
	11th to 20th	Day	7% 11% 31% 31% 14% 5%	488
	21st to end	Day	10% 9% 27% 33% 15% 6%	529
June	1st to 10th	Day	4 8% 26% 33% 22% 7%	490
	11th to 20th	Day	2 7% 26% 38% 20% 7%	490
	21st to end	Day	2 6% 27% 37% 19% 10%	487
July	1st to 10th	Day	2 1 15% 45% 25% 12%	446
	11th to 20th	Day	3 1 10% 43% 27% 16%	444
	21st to end	Day	2 1 12% 43% 28% 15%	487
August	1st to 10th	Day	2 1 20% 43% 21% 13%	447
	11th to 20th	Day	2 2 14% 43% 31% 9%	437
	21st to end	Day	1 1 15% 49% 23% 10%	495
September	1st to 10th	Day	2 3 23% 44% 22% 6%	450
	11th to 20th	Day	6% 30% 45% 17% 2	450
	21st to end	Day	1 8% 27% 42% 17% 4	450
October	1st to 10th	Day	4 9% 32% 36% 17% 2	450
	11th to 20th	Day	4 9% 36% 35% 14% 3	450
	21st to end	Day	5% 11% 31% 36% 14% 3	495
November	1st to 10th	Day	7% 11% 29% 31% 19% 3	284
	11th to 20th	Day	8% 11% 29% 34% 15% 4	270
	21st to end	Day	10% 14% 32% 27% 13% 3	270
December	1st to 10th	Day	8% 13% 34% 30% 13% 1	270
	11th to 20th	Day	12% 17% 24% 27% 16% 4	223
	21st to end	Day	18% 25% 24% 21% 10% 3	198
January	1st to 10th	Night	12% 9% 24% 30% 17% 7%	760
	11th to 20th	Night	8% 8% 29% 34% 16% 5%	760
	21st to end	Night	12% 12% 28% 29% 14% 5%	836
February	1st to 10th	Night	12% 10% 25% 31% 17% 5%	760
	11th to 20th	Night	10% 9% 26% 31% 16% 8%	744
	21st to end	Night	10% 13% 24% 33% 16% 3	628
March	1st to 10th	Night	10% 13% 24% 33% 18% 2	760
	11th to 20th	Night	8% 10% 23% 33% 22% 4	760
	21st to end	Night	9% 13% 22% 34% 20% 3	836
April	1st to 10th	Night	7% 10% 28% 34% 18% 4	760
	11th to 20th	Night	6% 9% 24% 34% 24% 3	751
	21st to end	Night	5% 8% 25% 32% 23% 7%	760
May	1st to 10th	Night	5% 6% 25% 34% 26% 5%	755
	11th to 20th	Night	4 7% 17% 36% 33% 3	561
	21st to end	Night	5% 6% 22% 32% 31% 5%	600
June	1st to 10th	Night	2 4 14% 39% 35% 5%	380
	11th to 20th	Night	2 12% 43% 37% 7%	380
	21st to end	Night	1 1 9% 40% 42% 7%	378
July	1st to 10th	Night	1 1 30% 58% 11%	350
	11th to 20th	Night	2 1 27% 56% 14%	381
	21st to end	Night	2 2 22% 55% 18%	663
August	1st to 10th	Night	2 4 31% 52% 10%	716
	11th to 20th	Night	2 27% 57% 13%	712
	21st to end	Night	2 1 28% 55% 14%	792
September	1st to 10th	Night	1 2 6% 28% 50% 14%	720
	11th to 20th	Night	1 7% 44% 38% 10%	720
	21st to end	Night	1 2 12% 36% 41% 9%	720
October	1st to 10th	Night	2 2 15% 44% 32% 5%	720
	11th to 20th	Night	3 4 18% 37% 30% 9%	720
	21st to end	Night	3 6% 19% 32% 30% 10%	792
November	1st to 10th	Night	3 9% 17% 38% 24% 9%	740
	11th to 20th	Night	5% 4 21% 38% 24% 8%	760
	21st to end	Night	6% 8% 26% 31% 23% 6%	760
December	1st to 10th	Night	8% 9% 25% 33% 21% 4	760
	11th to 20th	Night	12% 10% 20% 38% 15% 5%	760
	21st to end	Night	12% 11% 23% 33% 15% 6%	836

Page generated at 2024-06-26 19:18:46. Version ac07

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