Lake Taghkanic State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Taghkanic State Park clear sky chart from 2005-11-05 to 2009-12-29.

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	17% 6% 5% 5% 6% 5% 5% 7% 32%	16468
	Night	18% 7% 5% 5% 5% 5% 6% 33%	16464
Cloud Cover	Day	17% 6% 5% 5% 6% 5% 5% 7% 32%	16478
	Night	18% 7% 5% 5% 5% 5% 6% 33%	16484
Transparency	Day	8% 16% 23% 12%	12563
	Night	8% 16% 24% 13%	12777
Seeing	Day	11% 25% 26% 16%	1060
	Night	16% 34% 26% 6%	4819

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	15% 5% 5% 5% 9% 6% 6% 6% 30%	995
	Night	19% 8% 6% 5% 5% 5% 5% 6% 29%	1704
February	Day	14% 7% 6% 8% 8% 7% 5% 6% 27%	1052
	Night	14% 8% 5% 6% 7% 7% 5% 5% 6% 27%	1355
March	Day	16% 7% 5% 5% 5% 6% 37%	1320
	Night	18% 6% 5% 6% 5% 5% 35%	1358
April	Day	22% 6% 6% 36%	1434
	Night	19% 7% 5% 6% 5% 5% 33%	1170
May	Day	20% 5% 5% 5% 6% 6% 33%	1688
	Night	23% 5% 5% 5% 6% 36%	1025
June	Day	22% 5% 6% 6% 7% 6% 6% 9% 22%	1663
	Night	19% 5% 6% 5% 6% 6% 8% 29%	956
July	Day	13% 5% 5% 5% 8% 6% 6% 10% 30%	1716
	Night	17% 6% 5% 6% 9% 33%	974
August	Day	12% 5% 6% 6% 6% 5% 5% 8% 38%	1549
	Night	12% 5% 5% 6% 6% 6% 6% 39%	1163
September	Day	15% 5% 5% 7% 44%	1363
	Night	15% 6% 48%	1240
October	Day	18% 8% 5% 5% 5% 6% 34%	1202
	Night	22% 6% 5% 6% 35%	1491
November	Day	21% 9% 6% 5% 5% 31%	1269
	Night	22% 9% 7% 5% 5% 6% 27%	1902
December	Day	21% 8% 7% 6% 5% 8% 24%	1217
	Night	19% 9% 6% 5% 5% 6% 30%	2126

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	15% 5% 6% 9% 6% 6% 6% 30%	993
	Night	18% 9% 5% 6% 5% 5% 5% 6% 29%	1705
February	Day	14% 7% 5% 9% 8% 6% 5% 7% 28%	1049
	Night	14% 8% 5% 7% 7% 7% 5% 5% 6% 27%	1347
March	Day	16% 7% 5% 5% 5% 5% 6% 36%	1341
	Night	18% 6% 5% 5% 6% 5% 5% 34%	1382
April	Day	22% 7% 6% 36%	1433
	Night	18% 8% 5% 6% 5% 5% 33%	1170
May	Day	20% 6% 5% 6% 5% 6% 32%	1682
	Night	22% 6% 5% 5% 6% 36%	1019
June	Day	21% 5% 6% 6% 7% 6% 7% 9% 21%	1672
	Night	19% 5% 6% 5% 5% 6% 7% 7% 29%	958
July	Day	12% 5% 6% 5% 8% 6% 6% 9% 31%	1716
	Night	17% 7% 5% 7% 9% 33%	975
August	Day	12% 5% 5% 6% 6% 5% 5% 8% 38%	1544
	Night	12% 5% 5% 6% 6% 5% 6% 39%	1165
September	Day	15% 6% 7% 44%	1362
	Night	15% 6% 48%	1241
October	Day	18% 8% 5% 5% 5% 6% 35%	1202
	Night	22% 6% 5% 6% 35%	1491
November	Day	21% 8% 6% 5% 5% 5% 31%	1267
	Night	22% 9% 7% 5% 5% 6% 27%	1901
December	Day	20% 8% 7% 5% 6% 8% 24%	1217
	Night	19% 9% 6% 5% 5% 5% 6% 30%	2130

Transparency (when cloud cover <= 30%)
Color Meanings: Poor Below Average Average Above average Transparent
Month		Occurrence of each Forecast	Data Points
January	Day	12% 23% 24% 9%	717
	Night	9% 17% 25% 11%	1187
February	Day	8% 19% 20% 10%	774
	Night	10% 20% 23% 7%	992
March	Day	6% 15% 27% 17%	991
	Night	7% 17% 25% 14%	1051
April	Day	6% 13% 25% 16% 6%	1053
	Night	6% 12% 23% 19%	851
May	Day	8% 13% 26% 11%	1253
	Night	7% 15% 22% 17%	791
June	Day	12% 25% 18%	1174
	Night	13% 22% 23% 7%	684
July	Day	10% 20% 20% 12%	1093
	Night	10% 19% 28% 9%	655
August	Day	9% 12% 25% 16%	1351
	Night	7% 13% 27% 15%	1017
September	Day	7% 15% 24% 21%	1183
	Night	6% 9% 31% 23%	1084
October	Day	5% 11% 23% 14%	1053
	Night	17% 19% 14%	1296
November	Day	8% 14% 23% 10%	989
	Night	6% 17% 19% 9%	1463
December	Day	9% 20% 19% 6%	932
	Night	9% 18% 21% 8%	1706

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	17% 46% 22%	439
February	Day	20% 37% 26%	64
	Night	22% 40% 21%	402
March	Day	21% 27% 27% 6%	118
	Night	26% 40% 15%	462
April	Day	14% 29% 20% 11% 7%	109
	Night	19% 38% 23% 6%	420
May	Day	12% 32% 24% 11%	114
	Night	17% 33% 28% 5%	267
June	Day	6% 21% 32% 24%	102
	Night	8% 25% 39% 14%	209
July	Day	7% 23% 32% 24%	109
	Night	7% 24% 41% 14%	212
August	Day	14% 29% 21% 13%	116
	Night	26% 37% 16%	393
September	Day	6% 17% 26% 22% 12%	108
	Night	7% 28% 34% 12%	448
October	Day	12% 28% 23% 18%	117
	Night	12% 31% 28% 8%	470
November	Day	9% 32% 27% 9%	103
	Night	15% 33% 24% 6%	524
December	Night	24% 35% 19%	573

Page generated at 2009-12-30 05:20:34. Version ab11