Kennard Dale High School
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kennard Dale High School clear sky chart from 2005-11-06 to 2025-10-04.

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	15% 6% 2 6% 4 4 5% 4 6% 8% 40%	126521
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	122878
Transparency	Day	40% 6% 12% 23% 16% 3	130111
	Night	40% 5% 11% 23% 17% 3	127358
Seeing	Day	21% 15% 29% 21% 10% 3	16136
	Night	19% 14% 29% 26% 11% 1	25488

By Month

Percentage Cloud Cover SE (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	13% 6% 2 4 4 4 4 3 6% 6% 49%	3597
	11th to 20th	Day	13% 8% 3 8% 6% 5% 4 2 4 4 42%	3944
	21st to end	Day	15% 8% 3 7% 4 4 4 3 5% 6% 41%	4466
February	1st to 10th	Day	14% 9% 2 7% 5% 4 4 4 6% 8% 38%	1800
	11th to 20th	Day	16% 8% 3 6% 5% 5% 4 3 6% 6% 39%	1838
	21st to end	Day	17% 10% 3 6% 5% 3 3 2 4 5% 40%	1650
March	1st to 10th	Day	19% 5% 2 5% 4 4 4 3 4 5% 46%	4703
	11th to 20th	Day	11% 7% 2 7% 4 4 4 4 5% 7% 46%	4980
	21st to end	Day	16% 7% 2 6% 4 4 4 4 5% 6% 41%	5647
April	1st to 10th	Day	16% 8% 2 6% 5% 4 4 4 6% 7% 38%	2400
	11th to 20th	Day	14% 6% 2 6% 4 4 5% 4 5% 7% 43%	2374
	21st to end	Day	17% 6% 2 5% 4 4 4 3 6% 7% 41%	2400
May	1st to 10th	Day	26% 7% 2 5% 4 4 4 4 6% 8% 30%	5756
	11th to 20th	Day	24% 7% 3 6% 4 4 4 3 6% 8% 31%	6318
	21st to end	Day	17% 5% 2 6% 4 4 5% 4 7% 9% 36%	6934
June	1st to 10th	Day	12% 5% 2 6% 4 5% 5% 5% 8% 10% 38%	2800
	11th to 20th	Day	14% 5% 2 7% 5% 5% 6% 4 7% 9% 38%	2800
	21st to end	Day	10% 4 2 6% 4 5% 6% 4 7% 11% 42%	2800
July	1st to 10th	Day	7% 5% 2 7% 4 5% 6% 5% 8% 11% 41%	6360
	11th to 20th	Day	11% 7% 3 8% 5% 6% 6% 6% 8% 11% 30%	6360
	21st to end	Day	9% 6% 3 7% 5% 5% 5% 5% 7% 10% 39%	6517
August	1st to 10th	Day	18% 5% 2 7% 5% 6% 5% 5% 6% 8% 34%	4234
	11th to 20th	Day	12% 5% 2 6% 5% 4 6% 4 7% 9% 39%	3953
	21st to end	Day	11% 5% 2 5% 4 4 4 4 6% 8% 47%	4312
September	1st to 10th	Day	15% 5% 2 5% 4 4 5% 3 5% 5% 46%	2400
	11th to 20th	Day	13% 5% 1 4 5% 3 4 3 5% 8% 48%	2400
	21st to end	Day	21% 7% 3 6% 4 4 4 4 4 7% 36%	2130
October	1st to 10th	Day	17% 7% 2 5% 4 3 4 3 4 7% 45%	1930
	11th to 20th	Day	16% 5% 1 5% 3 3 3 4 5% 6% 47%	1900
	21st to end	Day	15% 7% 2 5% 4 3 4 3 5% 6% 46%	2090
November	1st to 10th	Day	12% 6% 2 5% 4 3 4 3 4 7% 51%	1778
	11th to 20th	Day	16% 5% 2 5% 3 4 4 4 5% 6% 48%	1800
	21st to end	Day	15% 7% 2 5% 4 4 4 3 4 7% 45%	1600
December	1st to 10th	Day	12% 7% 3 7% 4 4 4 3 5% 7% 44%	2600
	11th to 20th	Day	19% 10% 2 5% 3 4 4 3 5% 6% 40%	2990
	21st to end	Day	15% 8% 3 7% 5% 4 5% 4 6% 7% 38%	3960
January	1st to 10th	Night	12% 7% 2 5% 4 4 4 3 5% 7% 47%	6349
	11th to 20th	Night	14% 7% 2 5% 4 3 3 3 5% 6% 50%	6014
	21st to end	Night	16% 8% 2 6% 4 3 3 3 5% 5% 46%	6490
February	1st to 10th	Night	16% 8% 3 7% 4 4 3 3 5% 6% 40%	2600
	11th to 20th	Night	17% 8% 3 6% 4 4 4 3 4 6% 42%	2446
	21st to end	Night	15% 8% 3 6% 5% 5% 4 3 4 6% 41%	1980
March	1st to 10th	Night	16% 7% 2 6% 4 3 3 3 4 5% 47%	5147
	11th to 20th	Night	10% 7% 3 4 3 4 4 3 5% 6% 51%	4980
	21st to end	Night	13% 8% 3 6% 4 4 4 3 4 6% 45%	5284
April	1st to 10th	Night	17% 8% 2 8% 4 4 4 3 5% 7% 38%	2000
	11th to 20th	Night	15% 6% 2 6% 5% 3 4 4 5% 8% 42%	1975
	21st to end	Night	18% 7% 2 5% 4 2 4 4 5% 6% 44%	2000
May	1st to 10th	Night	25% 8% 3 6% 4 4 4 3 6% 8% 30%	4164
	11th to 20th	Night	24% 10% 3 6% 4 2 4 3 6% 7% 30%	3575
	21st to end	Night	19% 6% 2 5% 3 3 5% 4 6% 9% 37%	3920
June	1st to 10th	Night	12% 5% 2 6% 5% 4 3 4 6% 9% 45%	1600
	11th to 20th	Night	12% 6% 2 6% 5% 5% 5% 4 7% 9% 40%	1600
	21st to end	Night	11% 4 1 6% 4 5% 5% 5% 7% 10% 43%	1600
July	1st to 10th	Night	8% 6% 2 8% 5% 5% 6% 4 7% 9% 39%	3598
	11th to 20th	Night	11% 7% 3 8% 6% 6% 6% 6% 7% 10% 30%	3597
	21st to end	Night	10% 6% 2 6% 4 5% 4 5% 6% 8% 44%	4329
August	1st to 10th	Night	19% 6% 2 6% 4 4 5% 4 5% 10% 35%	2915
	11th to 20th	Night	12% 7% 2 7% 5% 4 5% 4 5% 8% 39%	3062
	21st to end	Night	12% 5% 2 5% 4 3 4 3 5% 8% 48%	3586
September	1st to 10th	Night	13% 6% 3 5% 5% 3 3 3 5% 7% 47%	2000
	11th to 20th	Night	12% 6% 2 6% 3 3 3 3 4 7% 52%	2000
	21st to end	Night	20% 8% 2 6% 4 3 4 3 4 6% 40%	2266
October	1st to 10th	Night	20% 6% 3 5% 3 3 3 3 5% 5% 44%	2317
	11th to 20th	Night	16% 5% 2 4 3 3 3 3 5% 6% 51%	2280
	21st to end	Night	16% 6% 2 4 3 3 4 3 5% 7% 48%	2508
November	1st to 10th	Night	10% 6% 2 4 4 4 3 3 4 6% 53%	2518
	11th to 20th	Night	16% 6% 2 5% 4 3 4 3 4 6% 47%	2600
	21st to end	Night	13% 5% 2 5% 4 4 4 4 5% 7% 47%	2797
December	1st to 10th	Night	11% 6% 2 6% 4 4 4 3 5% 7% 48%	4580
	11th to 20th	Night	21% 7% 2 5% 4 3 4 3 5% 6% 40%	5205
	21st to end	Night	17% 7% 3 7% 4 4 5% 4 6% 7% 36%	6996

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	34% 4 9% 26% 23% 4	3598
	11th to 20th	Day	45% 3 8% 20% 16% 6%	3944
	21st to end	Day	44% 4 12% 25% 13% 2	4466
February	1st to 10th	Day	43% 5% 13% 26% 11% 2	1800
	11th to 20th	Day	45% 4 10% 25% 14% 3	1847
	21st to end	Day	47% 3 10% 22% 13% 4	1650
March	1st to 10th	Day	39% 4 9% 24% 17% 7%	4703
	11th to 20th	Day	36% 5% 10% 27% 16% 6%	4980
	21st to end	Day	44% 4 9% 18% 19% 5%	5647
April	1st to 10th	Day	43% 5% 12% 20% 16% 5%	2400
	11th to 20th	Day	40% 6% 12% 21% 17% 5%	2374
	21st to end	Day	41% 5% 10% 21% 19% 4	2400
May	1st to 10th	Day	50% 7% 13% 17% 11% 2	5789
	11th to 20th	Day	51% 7% 11% 21% 10% 1	6322
	21st to end	Day	42% 6% 12% 23% 15% 1	6949
June	1st to 10th	Day	39% 7% 13% 23% 16% 2	2800
	11th to 20th	Day	41% 7% 13% 24% 12% 3	2800
	21st to end	Day	33% 8% 15% 25% 17% 2	2800
July	1st to 10th	Day	35% 11% 16% 20% 16% 3	6290
	11th to 20th	Day	43% 11% 16% 20% 8% 1	6285
	21st to end	Day	37% 8% 11% 22% 21% 1	6330
August	1st to 10th	Day	46% 8% 13% 24% 9%	4221
	11th to 20th	Day	38% 8% 12% 27% 14% 1	3992
	21st to end	Day	33% 6% 12% 28% 18% 2	4312
September	1st to 10th	Day	39% 6% 11% 21% 20% 4	2400
	11th to 20th	Day	34% 5% 10% 27% 21% 3	2400
	21st to end	Day	48% 5% 8% 19% 18% 2	2130
October	1st to 10th	Day	37% 4 7% 19% 28% 5%	3190
	11th to 20th	Day	26% 4 10% 25% 24% 10%	3140
	21st to end	Day	25% 3 11% 30% 28% 4	3428
November	1st to 10th	Day	34% 3 13% 24% 21% 4	1778
	11th to 20th	Day	36% 5% 10% 24% 22% 3	1800
	21st to end	Day	40% 4 11% 30% 13% 2	1600
December	1st to 10th	Day	40% 4 16% 26% 12% 3	2600
	11th to 20th	Day	44% 5% 12% 29% 10% 1	2986
	21st to end	Day	44% 6% 15% 19% 15% 2	3960
January	1st to 10th	Night	36% 4 9% 26% 21% 4	6349
	11th to 20th	Night	36% 4 10% 25% 18% 7%	6014
	21st to end	Night	41% 3 9% 27% 18% 2	6490
February	1st to 10th	Night	44% 4 14% 24% 12% 1	2600
	11th to 20th	Night	44% 4 9% 21% 18% 4	2448
	21st to end	Night	45% 4 10% 20% 16% 5%	1980
March	1st to 10th	Night	40% 4 9% 26% 12% 10%	5147
	11th to 20th	Night	33% 5% 12% 30% 14% 6%	4980
	21st to end	Night	40% 4 8% 19% 25% 4	5284
April	1st to 10th	Night	45% 4 10% 19% 18% 4	2000
	11th to 20th	Night	39% 5% 12% 20% 19% 5%	1975
	21st to end	Night	39% 5% 10% 22% 19% 5%	2000
May	1st to 10th	Night	53% 5% 12% 16% 11% 3	4194
	11th to 20th	Night	52% 6% 11% 19% 11% 1	3576
	21st to end	Night	43% 7% 12% 23% 12% 2	3927
June	1st to 10th	Night	37% 7% 11% 24% 18% 2	1600
	11th to 20th	Night	40% 6% 14% 24% 15% 1	1600
	21st to end	Night	35% 7% 13% 27% 16% 3	1600
July	1st to 10th	Night	40% 9% 17% 17% 14% 3	3560
	11th to 20th	Night	44% 11% 17% 17% 9% 1	3552
	21st to end	Night	36% 8% 12% 23% 20% 1	4202
August	1st to 10th	Night	45% 7% 18% 21% 9% 1	2904
	11th to 20th	Night	42% 6% 11% 27% 14% 1	3089
	21st to end	Night	34% 5% 11% 31% 17% 2	3586
September	1st to 10th	Night	38% 6% 11% 21% 21% 4	2000
	11th to 20th	Night	33% 4 10% 24% 25% 4	2000
	21st to end	Night	46% 5% 9% 19% 19% 2	2266
October	1st to 10th	Night	42% 5% 10% 19% 21% 2	3837
	11th to 20th	Night	24% 3 11% 26% 29% 6%	3779
	21st to end	Night	25% 3 11% 32% 24% 5%	4120
November	1st to 10th	Night	32% 4 10% 26% 22% 5%	2518
	11th to 20th	Night	39% 3 9% 24% 20% 5%	2600
	21st to end	Night	37% 4 12% 27% 18% 2	2797
December	1st to 10th	Night	36% 4 13% 30% 15% 2	4580
	11th to 20th	Night	45% 4 13% 19% 16% 3	5208
	21st to end	Night	45% 6% 12% 19% 17% 1	6996

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	32% 28% 26% 12% 2 1	200
	11th to 20th	Day	37% 23% 27% 12% 1	275
	21st to end	Day	24% 32% 31% 10% 3	330
February	1st to 10th	Day	28% 27% 33% 9% 2 1	300
	11th to 20th	Day	38% 25% 32% 4 1	385
	21st to end	Day	34% 23% 29% 13% 2	414
March	1st to 10th	Day	28% 24% 31% 15% 3	500
	11th to 20th	Day	28% 23% 32% 12% 4 1	500
	21st to end	Day	26% 25% 31% 13% 4 1	550
April	1st to 10th	Day	26% 25% 33% 11% 4 1	500
	11th to 20th	Day	24% 22% 29% 16% 6% 2	492
	21st to end	Day	27% 19% 33% 14% 6% 1	500
May	1st to 10th	Day	29% 17% 30% 15% 7% 2	503
	11th to 20th	Day	25% 15% 31% 20% 7% 2	527
	21st to end	Day	21% 9% 25% 26% 16% 3	573
June	1st to 10th	Day	16% 12% 31% 25% 12% 4	530
	11th to 20th	Day	18% 11% 27% 28% 13% 3	530
	21st to end	Day	13% 9% 32% 28% 12% 5%	530
July	1st to 10th	Day	12% 5% 22% 33% 22% 7%	525
	11th to 20th	Day	6% 5% 25% 35% 22% 6%	524
	21st to end	Day	12% 7% 26% 33% 18% 4	576
August	1st to 10th	Day	12% 5% 26% 32% 19% 7%	526
	11th to 20th	Day	11% 7% 21% 34% 19% 8%	519
	21st to end	Day	11% 6% 26% 31% 18% 8%	583
September	1st to 10th	Day	19% 8% 22% 25% 18% 8%	530
	11th to 20th	Day	15% 7% 24% 29% 17% 8%	530
	21st to end	Day	29% 9% 23% 24% 11% 3	530
October	1st to 10th	Day	24% 8% 24% 24% 13% 7%	502
	11th to 20th	Day	20% 15% 28% 23% 12% 2	490
	21st to end	Day	17% 18% 36% 18% 9% 2	539
November	1st to 10th	Day	18% 15% 33% 21% 10% 2	403
	11th to 20th	Day	19% 22% 33% 20% 7% 1	400
	21st to end	Day	30% 20% 31% 16% 5% 1	200
December	1st to 10th	Day	25% 25% 36% 11% 3 1	200
	11th to 20th	Day	30% 26% 30% 12% 4	200
	21st to end	Day	25% 20% 33% 15% 6%	220
January	1st to 10th	Night	22% 22% 38% 16% 3	800
	11th to 20th	Night	26% 19% 33% 20% 3	800
	21st to end	Night	20% 22% 38% 18% 1	880
February	1st to 10th	Night	24% 19% 35% 20% 3	800
	11th to 20th	Night	28% 24% 34% 14% 1	783
	21st to end	Night	24% 23% 34% 16% 3	660
March	1st to 10th	Night	22% 23% 35% 17% 4	800
	11th to 20th	Night	23% 22% 32% 17% 5%	800
	21st to end	Night	22% 18% 38% 16% 4	880
April	1st to 10th	Night	23% 22% 34% 18% 3	800
	11th to 20th	Night	20% 16% 35% 24% 6%	791
	21st to end	Night	23% 15% 31% 25% 6%	800
May	1st to 10th	Night	23% 10% 30% 28% 7% 1	669
	11th to 20th	Night	22% 11% 30% 28% 8%	394
	21st to end	Night	18% 6% 22% 37% 15% 1	433
June	1st to 10th	Night	14% 3 27% 40% 16% 1	400
	11th to 20th	Night	13% 5% 27% 40% 14% 1	400
	21st to end	Night	11% 3 26% 42% 17%	400
July	1st to 10th	Night	10% 5% 19% 39% 25% 3	390
	11th to 20th	Night	7% 3 18% 40% 28% 3	388
	21st to end	Night	8% 3 20% 44% 22% 3	611
August	1st to 10th	Night	13% 3 15% 42% 25% 2	597
	11th to 20th	Night	15% 5% 15% 36% 27% 2	703
	21st to end	Night	14% 4 17% 39% 24% 4	880
September	1st to 10th	Night	15% 5% 22% 33% 21% 3	800
	11th to 20th	Night	15% 5% 18% 34% 24% 5%	800
	21st to end	Night	23% 6% 22% 30% 18% 2	800
October	1st to 10th	Night	23% 8% 22% 25% 17% 5%	773
	11th to 20th	Night	19% 12% 27% 30% 13% 1	760
	21st to end	Night	20% 13% 31% 24% 12%	836
November	1st to 10th	Night	14% 13% 34% 28% 10% 1	780
	11th to 20th	Night	21% 19% 31% 23% 7% 1	800
	21st to end	Night	17% 19% 32% 24% 7%	800
December	1st to 10th	Night	24% 18% 33% 18% 7%	800
	11th to 20th	Night	21% 18% 37% 20% 4	800
	21st to end	Night	21% 19% 31% 25% 3	880

Page generated at 2025-10-01 01:39:06. Version ac07

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