Reserve Faunique La Verendrye
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Reserve Faunique La Verendrye 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	24% 7% 6% 5% 6% 5% 6% 26%	8779
	Night	23% 7% 6% 5% 5% 6% 6% 25%	8393
Transparency	Day	18% 23% 39% 16%	3735
	Night	18% 22% 41% 16%	3411
Seeing	Day	16% 34% 26% 18%	494
	Night	17% 35% 33% 13%	2153

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% 9% 7% 6% 6% 7% 13% 21%	495
	Night	17% 10% 9% 6% 6% 8% 5% 8% 8% 14%	858
February	Day	20% 9% 8% 7% 5% 5% 27%	525
	Night	20% 7% 7% 7% 6% 6% 6% 24%	729
March	Day	25% 8% 5% 8% 32%	676
	Night	20% 8% 5% 7% 7% 5% 5% 6% 27%	688
April	Day	32% 7% 5% 26%	745
	Night	28% 6% 5% 5% 5% 29%	577
May	Day	26% 7% 6% 5% 6% 5% 5% 24%	863
	Night	29% 6% 7% 30%	490
June	Day	17% 5% 6% 5% 5% 9% 5% 9% 28%	860
	Night	19% 7% 6% 5% 6% 6% 5% 8% 28%	456
July	Day	18% 5% 5% 7% 5% 5% 6% 31%	869
	Night	18% 5% 6% 5% 8% 38%	492
August	Day	21% 7% 6% 6% 5% 7% 7% 27%	1208
	Night	20% 7% 5% 7% 6% 31%	830
September	Day	17% 5% 5% 6% 5% 8% 36%	1019
	Night	19% 5% 5% 7% 5% 7% 34%	926
October	Day	28% 10% 7% 5% 5% 23%	602
	Night	26% 10% 7% 5% 5% 5% 6% 21%	760
November	Day	39% 9% 9% 6% 5% 5% 11%	431
	Night	35% 10% 8% 5% 5% 5% 16%	735
December	Day	37% 10% 5% 5% 5% 6% 15%	486
	Night	32% 9% 5% 7% 10% 15%	852

Transparency (when cloud cover <= 30%)
Color Meanings: Poor Below Average Average Above average Transparent
Month		Occurrence of each Forecast	Data Points
January	Day	17% 14% 56% 10%	231
	Night	10% 20% 56% 12%	296
February	Day	38% 23% 27% 10%	204
	Night	22% 22% 33% 20%	276
March	Day	19% 33% 31% 13%	292
	Night	14% 37% 36% 8%	296
April	Day	16% 11% 38% 32%	269
	Night	18% 11% 31% 36%	226
May	Day	21% 20% 42% 13%	332
	Night	18% 19% 42% 16%	205
June	Day	17% 17% 47% 14%	392
	Night	24% 13% 45% 14%	201
July	Day	16% 17% 35% 25%	408
	Night	15% 14% 38% 30%	272
August	Day	16% 26% 45% 9%	533
	Night	19% 26% 39% 13%	378
September	Day	12% 32% 37% 16%	538
	Night	16% 19% 48% 15%	467
October	Day	23% 26% 33% 16%	299
	Night	26% 24% 38% 9%	406
November	Day	24% 37% 33%	109
	Night	23% 27% 39% 10%	192
December	Day	17% 17% 39% 18% 6%	128
	Night	9% 25% 39% 23%	196

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	Night	21% 45% 25% 7%	186
February	Day	10% 30% 10% 20% 30%	10
	Night	12% 37% 32% 12%	177
March	Day	20% 26% 24% 24%	49
	Night	19% 32% 32% 14%	199
April	Day	11% 45% 30% 9%	42
	Night	15% 43% 35% 6%	153
May	Day	11% 37% 32% 11% 6%	43
	Night	17% 28% 43% 7%	91
June	Day	20% 50% 16% 11%	68
	Night	18% 43% 25% 11%	101
July	Day	7% 25% 47% 19%	51
	Night	9% 33% 38% 16%	106
August	Day	17% 29% 20% 28%	78
	Night	12% 30% 35% 19%	221
September	Day	11% 42% 20% 17% 7%	78
	Night	15% 33% 32% 17%	306
October	Day	23% 18% 33% 21%	65
	Night	18% 26% 38% 15%	285
November	Day	50% 30% 20%	10
	Night	28% 39% 29%	167
December	Night	14% 34% 34% 14%	161

Page generated at 2008-09-30 05:41:01. Version ab11