Lake Riverside Estates
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Riverside Estates clear sky chart from 2003-08-01 to 2005-11-07.

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	8% 66%	8664
	Night	10% 5% 59%	8504
Transparency	Day	18% 33% 38%	6895
	Night	6% 19% 32% 37%	6426
Seeing	Day	17% 39% 37% 5%	623
	Night	6% 16% 31% 37% 8%	2928

By Month

Percentage Cloud Cover
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month		Occurrence of each Forecast	Data Points
January	Day	17% 5% 5% 47%	578
	Night	19% 5% 5% 5% 44%	775
February	Day	30% 8% 5% 7% 5% 29%	561
	Night	31% 6% 6% 5% 31%	684
March	Day	10% 5% 5% 59%	662
	Night	12% 6% 54%	698
April	Day	5% 6% 5% 66%	720
	Night	7% 5% 6% 57%	600
May	Day	69%	802
	Night	5% 7% 7% 57%	562
June	Day	88%	780
	Night	8% 76%	537
July	Day	74%	788
	Night	5% 5% 5% 71%	564
August	Day	5% 7% 67%	1114
	Night	5% 6% 67%	929
September	Day	81%	994
	Night	79%	951
October	Day	12% 70%	648
	Night	8% 64%	716
November	Day	14% 56%	468
	Night	11% 5% 5% 56%	698
December	Day	23% 54%	549
	Night	20% 51%	790

Transparency (when cloud cover <= 30%)
Color Meanings: Poor Below Average Average Above average Transparent
Month		Occurrence of each Forecast	Data Points
January	Day	10% 5% 33% 36% 13%	342
	Night	9% 6% 21% 42% 21%	442
February	Day	13% 6% 30% 30% 19%	222
	Night	10% 10% 31% 31% 15%	269
March	Day	8% 9% 23% 30% 28%	459
	Night	7% 7% 22% 28% 35%	440
April	Day	6% 6% 26% 37% 22%	565
	Night	26% 32% 30%	423
May	Day	9% 21% 32% 35%	641
	Night	7% 10% 14% 28% 39%	428
June	Day	18% 40% 35%	745
	Night	7% 23% 39% 26%	491
July	Day	16% 31% 46%	663
	Night	18% 30% 45%	466
August	Day	7% 5% 16% 28% 41%	885
	Night	8% 19% 32% 38%	723
September	Day	7% 24% 64%	923
	Night	9% 28% 57%	866
October	Day	12% 38% 40%	777
	Night	7% 16% 30% 42%	833
November	Day	9% 6% 27% 33% 24%	333
	Night	6% 9% 32% 24% 27%	543
December	Day	10% 34% 50%	340
	Night	5% 8% 43% 40%	502

Seeing (when cloud cover <= 80%)
Color Meanings: Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month		Occurrence of each Forecast	Data Points
January	Day	26% 42% 26%	26
	Night	9% 22% 35% 27%	214
February	Day	45% 36% 15%	44
	Night	17% 37% 29% 16%	172
March	Day	22% 35% 27% 15%	59
	Night	13% 20% 28% 31% 5%	234
April	Day	35% 46% 16%	60
	Night	11% 25% 34% 25%	228
May	Day	24% 44% 29%	61
	Night	27% 39% 25% 5%	185
June	Day	6% 41% 50%	60
	Night	10% 33% 51%	180
July	Day	40% 51%	62
	Night	23% 59% 14%	192
August	Day	27% 63%	91
	Night	18% 56% 20%	364
September	Day	10% 43% 40% 6%	90
	Night	6% 32% 48% 11%	360
October	Day	17% 38% 31% 11%	70
	Night	9% 32% 42% 9%	355
November	Night	11% 26% 39% 19%	233
December	Night	14% 23% 36% 20%	211

Page generated at 2008-09-30 02:41:08. Version ab11