Kansas City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kansas City clear sky chart from 2005-11-05 to 2008-11-27.

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	13% 6% 5% 5% 7% 40%	12239
	Night	11% 5% 8% 45%	12191
Transparency	Day	20% 31% 17%	8918
	Night	19% 32% 20%	9273
Seeing	Day	7% 27% 34% 20%	743
	Night	12% 36% 32% 10%	3758

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	13% 6% 5% 5% 6% 5% 42%	833
	Night	8% 9% 49%	1207
February	Day	11% 11% 7% 6% 6% 7% 34%	759
	Night	12% 8% 6% 5% 5% 7% 37%	1022
March	Day	20% 9% 5% 6% 6% 7% 28%	1022
	Night	15% 6% 5% 5% 8% 38%	1021
April	Day	18% 8% 5% 39%	1085
	Night	16% 5% 5% 47%	890
May	Day	16% 7% 5% 5% 7% 5% 6% 33%	1221
	Night	10% 6% 6% 5% 5% 8% 41%	824
June	Day	10% 7% 5% 7% 10% 40%	1260
	Night	7% 5% 5% 12% 51%	720
July	Day	7% 5% 6% 5% 7% 5% 10% 41%	1212
	Night	5% 6% 5% 9% 11% 43%	829
August	Day	9% 6% 6% 11% 45%	1171
	Night	6% 5% 5% 5% 9% 47%	861
September	Day	13% 5% 5% 5% 6% 45%	1019
	Night	11% 5% 7% 51%	955
October	Day	18% 5% 5% 6% 48%	922
	Night	16% 52%	1111
November	Day	13% 7% 6% 49%	982
	Night	10% 6% 6% 52%	1460
December	Day	14% 10% 5% 6% 5% 8% 33%	753
	Night	16% 8% 5% 5% 5% 8% 34%	1291

Transparency (when cloud cover <= 30%)
Color Meanings: Poor Below Average Average Above average Transparent
Month		Occurrence of each Forecast	Data Points
January	Day	24% 31% 18%	579
	Night	19% 37% 24%	911
February	Day	34% 24% 8%	542
	Night	27% 31% 11%	725
March	Day	28% 24% 10%	625
	Night	6% 24% 28% 16%	718
April	Day	16% 31% 22%	779
	Night	11% 32% 28%	689
May	Day	8% 20% 27% 17%	790
	Night	5% 25% 24% 20%	591
June	Day	24% 39% 17%	923
	Night	5% 24% 34% 20%	593
July	Day	22% 33% 13% 6%	743
	Night	18% 34% 16% 6%	527
August	Day	5% 16% 31% 20%	974
	Night	16% 30% 26%	708
September	Day	13% 29% 20%	882
	Night	11% 32% 25%	832
October	Day	12% 26% 26%	784
	Night	11% 25% 27% 7%	947
November	Day	19% 39% 16%	781
	Night	19% 39% 18%	1144
December	Day	28% 33% 6%	516
	Night	26% 32% 9%	888

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% 52% 19%	439
February	Night	15% 44% 28%	338
March	Night	19% 39% 26% 5%	252
April	Day	13% 35% 31% 7%	82
	Night	16% 34% 35%	245
May	Day	10% 40% 28% 12%	169
	Night	5% 41% 34% 10%	268
June	Day	7% 31% 31% 21%	161
	Night	5% 21% 51% 17%	243
July	Day	23% 45% 22%	151
	Night	17% 48% 24%	233
August	Day	5% 12% 36% 32% 6%	149
	Night	15% 46% 27%	259
September	Day	38% 22% 12%	31
	Night	18% 33% 25% 6%	255
October	Night	13% 37% 26% 10%	339
November	Night	15% 44% 29%	478
December	Night	14% 42% 27%	409

Page generated at 2008-11-27 12:47:34. Version ab11