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 2024-04-25.

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 5% 5% 3 5% 5% 6% 7% 41%	83357
	Night	15% 6% 3 5% 5% 3 4 4 5% 7% 43%	85757
Transparency	Day	41% 6% 12% 23% 15% 3	83064
	Night	41% 5% 11% 24% 16% 3	85569
Seeing	Day	21% 15% 28% 21% 11% 3	14189
	Night	19% 14% 29% 26% 11% 1	23736

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	15% 6% 2 4 4 3 4 5% 5% 6% 46%	2517
	11th to 20th	Day	14% 9% 3 8% 7% 4 5% 3 4 5% 36%	2752
	21st to end	Day	18% 9% 4 6% 6% 3 5% 4 5% 5% 35%	3124
February	1st to 10th	Day	14% 8% 3 6% 5% 3 5% 5% 5% 8% 38%	1710
	11th to 20th	Day	16% 7% 3 5% 6% 4 3 4 6% 7% 40%	1743
	21st to end	Day	18% 9% 3 6% 6% 2 4 3 4 5% 39%	1570
March	1st to 10th	Day	23% 6% 2 4 4 3 4 4 4 6% 39%	3273
	11th to 20th	Day	9% 5% 2 6% 6% 3 5% 6% 6% 7% 46%	3480
	21st to end	Day	20% 8% 3 5% 4 2 4 3 4 4 42%	3941
April	1st to 10th	Day	15% 6% 3 5% 5% 3 5% 5% 6% 8% 38%	2280
	11th to 20th	Day	14% 5% 2 5% 5% 3 5% 4 5% 7% 44%	2254
	21st to end	Day	18% 5% 2 4 5% 3 4 4 6% 6% 41%	2210
May	1st to 10th	Day	17% 7% 3 5% 5% 3 4 5% 6% 7% 37%	2288
	11th to 20th	Day	21% 6% 3 4 5% 3 4 5% 5% 8% 36%	2478
	21st to end	Day	14% 6% 2 5% 5% 3 4 5% 5% 10% 39%	2725
June	1st to 10th	Day	13% 5% 2 6% 5% 3 5% 6% 7% 11% 37%	2520
	11th to 20th	Day	13% 5% 2 6% 5% 4 6% 5% 7% 9% 38%	2520
	21st to end	Day	10% 3 2 5% 5% 3 5% 6% 7% 11% 42%	2520
July	1st to 10th	Day	9% 5% 2 5% 5% 4 6% 6% 8% 10% 40%	2520
	11th to 20th	Day	6% 3 2 5% 5% 4 6% 8% 8% 11% 43%	2520
	21st to end	Day	9% 6% 3 6% 6% 4 6% 5% 8% 9% 36%	2584
August	1st to 10th	Day	9% 6% 2 6% 6% 5% 7% 6% 7% 9% 38%	2327
	11th to 20th	Day	10% 6% 3 5% 7% 3 6% 6% 7% 9% 38%	2187
	21st to end	Day	12% 5% 2 5% 5% 3 5% 6% 6% 9% 40%	2376
September	1st to 10th	Day	16% 6% 2 5% 5% 3 5% 5% 5% 6% 43%	2160
	11th to 20th	Day	13% 4 1 4 5% 2 4 3 5% 8% 49%	2160
	21st to end	Day	19% 7% 3 5% 4 3 4 5% 5% 7% 39%	1918
October	1st to 10th	Day	18% 6% 2 5% 4 3 4 4 4 7% 43%	1800
	11th to 20th	Day	18% 5% 2 4 4 3 3 5% 5% 6% 46%	1800
	21st to end	Day	16% 7% 3 5% 5% 2 4 4 5% 6% 44%	1980
November	1st to 10th	Day	13% 5% 2 5% 3 2 4 4 4 6% 51%	1688
	11th to 20th	Day	16% 5% 2 4 3 3 4 5% 5% 6% 48%	1710
	21st to end	Day	16% 5% 3 4 4 3 5% 3 4 7% 45%	1520
December	1st to 10th	Day	17% 7% 3 5% 5% 4 4 4 4 8% 38%	1520
	11th to 20th	Day	18% 8% 2 5% 4 2 5% 4 5% 7% 40%	1910
	21st to end	Day	15% 7% 3 6% 6% 3 5% 5% 5% 6% 36%	2772
January	1st to 10th	Night	15% 7% 3 6% 5% 3 4 4 5% 7% 42%	4429
	11th to 20th	Night	18% 8% 3 5% 4 2 3 3 4 6% 44%	4206
	21st to end	Night	21% 8% 3 5% 5% 2 3 3 4 6% 39%	4532
February	1st to 10th	Night	16% 8% 3 6% 5% 3 4 4 5% 6% 41%	2470
	11th to 20th	Night	17% 7% 3 5% 4 3 4 4 4 6% 42%	2321
	21st to end	Night	16% 8% 3 6% 5% 4 4 4 4 6% 41%	1884
March	1st to 10th	Night	21% 8% 3 6% 4 3 3 4 4 6% 39%	3577
	11th to 20th	Night	10% 5% 2 4 4 3 4 5% 5% 6% 51%	3480
	21st to end	Night	15% 9% 3 5% 4 2 3 3 3 5% 47%	3690
April	1st to 10th	Night	16% 7% 2 7% 5% 3 4 4 5% 8% 39%	1900
	11th to 20th	Night	15% 6% 2 5% 5% 2 4 5% 5% 8% 43%	1875
	21st to end	Night	19% 7% 2 4 4 2 3 5% 5% 6% 43%	1850
May	1st to 10th	Night	18% 7% 3 5% 5% 2 5% 4 6% 8% 39%	1684
	11th to 20th	Night	19% 7% 2 6% 5% 2 5% 4 5% 7% 38%	1415
	21st to end	Night	14% 6% 3 3 4 3 5% 5% 6% 10% 41%	1550
June	1st to 10th	Night	12% 5% 2 5% 5% 4 4 4 5% 9% 46%	1440
	11th to 20th	Night	11% 6% 2 5% 6% 3 5% 6% 6% 10% 39%	1440
	21st to end	Night	11% 3 2 4 5% 3 5% 7% 7% 10% 44%	1440
July	1st to 10th	Night	9% 6% 3 7% 6% 4 6% 6% 7% 9% 37%	1440
	11th to 20th	Night	6% 3 2 5% 5% 4 6% 6% 6% 12% 46%	1440
	21st to end	Night	9% 3 2 5% 5% 4 6% 6% 6% 10% 45%	1729
August	1st to 10th	Night	10% 4 2 4 6% 4 5% 6% 7% 10% 42%	1611
	11th to 20th	Night	11% 7% 2 6% 6% 3 6% 5% 6% 9% 39%	1695
	21st to end	Night	13% 5% 2 4 5% 3 5% 5% 6% 9% 44%	1980
September	1st to 10th	Night	15% 6% 3 4 6% 2 4 3 5% 7% 46%	1800
	11th to 20th	Night	12% 6% 2 5% 3 2 4 3 4 7% 54%	1800
	21st to end	Night	17% 7% 2 5% 5% 3 4 4 4 6% 43%	2038
October	1st to 10th	Night	21% 6% 3 4 3 2 3 4 5% 5% 44%	2160
	11th to 20th	Night	17% 5% 2 3 4 2 3 4 5% 6% 50%	2160
	21st to end	Night	17% 6% 2 3 3 2 4 4 5% 7% 47%	2376
November	1st to 10th	Night	11% 5% 2 4 4 3 4 4 4 6% 53%	2389
	11th to 20th	Night	16% 5% 3 5% 4 2 4 3 4 6% 48%	2470
	21st to end	Night	13% 5% 2 5% 4 3 4 4 5% 7% 47%	2657
December	1st to 10th	Night	17% 7% 3 5% 5% 4 4 5% 5% 7% 39%	2660
	11th to 20th	Night	17% 6% 2 5% 5% 3 4 4 5% 7% 42%	3285
	21st to end	Night	16% 7% 3 6% 6% 4 5% 6% 6% 8% 34%	4884

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	38% 5% 12% 28% 14% 4	2518
	11th to 20th	Day	50% 4 10% 19% 13% 4	2752
	21st to end	Day	51% 4 12% 23% 9% 2	3124
February	1st to 10th	Day	43% 5% 13% 25% 11% 2	1710
	11th to 20th	Day	44% 4 10% 26% 14% 3	1752
	21st to end	Day	48% 3 10% 21% 13% 4	1570
March	1st to 10th	Day	45% 4 11% 26% 12% 3	3273
	11th to 20th	Day	34% 6% 10% 27% 19% 4	3480
	21st to end	Day	46% 3 9% 21% 18% 4	3941
April	1st to 10th	Day	42% 5% 12% 20% 16% 5%	2280
	11th to 20th	Day	39% 6% 12% 21% 17% 5%	2254
	21st to end	Day	41% 5% 11% 20% 18% 4	2210
May	1st to 10th	Day	46% 5% 10% 21% 15% 3	2288
	11th to 20th	Day	47% 6% 12% 20% 12% 3	2482
	21st to end	Day	40% 6% 16% 22% 13% 2	2725
June	1st to 10th	Day	40% 7% 14% 23% 15% 2	2520
	11th to 20th	Day	41% 7% 13% 23% 13% 2	2520
	21st to end	Day	33% 8% 15% 25% 17% 1	2520
July	1st to 10th	Day	37% 9% 14% 22% 15% 3	2450
	11th to 20th	Day	31% 8% 17% 27% 14% 3	2445
	21st to end	Day	39% 9% 13% 22% 15% 2	2439
August	1st to 10th	Day	40% 8% 14% 24% 13% 1	2314
	11th to 20th	Day	39% 8% 14% 22% 15% 2	2187
	21st to end	Day	38% 7% 14% 24% 14% 4	2376
September	1st to 10th	Day	41% 6% 11% 21% 18% 4	2160
	11th to 20th	Day	34% 5% 10% 26% 21% 4	2160
	21st to end	Day	44% 5% 8% 20% 20% 2	1918
October	1st to 10th	Day	41% 5% 10% 25% 17% 2	1800
	11th to 20th	Day	39% 4 11% 23% 21% 2	1800
	21st to end	Day	41% 4 9% 27% 18% 2	1980
November	1st to 10th	Day	34% 4 13% 25% 20% 4	1688
	11th to 20th	Day	37% 4 10% 24% 22% 3	1710
	21st to end	Day	40% 3 11% 30% 13% 3	1520
December	1st to 10th	Day	45% 4 14% 23% 12% 1	1520
	11th to 20th	Day	42% 5% 11% 31% 10% 1	1906
	21st to end	Day	47% 5% 15% 21% 12% 1	2772
January	1st to 10th	Night	41% 5% 11% 27% 13% 3	4429
	11th to 20th	Night	42% 5% 10% 26% 14% 2	4206
	21st to end	Night	47% 4 8% 28% 12% 2	4532
February	1st to 10th	Night	44% 4 13% 24% 12% 1	2470
	11th to 20th	Night	44% 4 9% 21% 18% 4	2323
	21st to end	Night	45% 4 10% 20% 15% 5%	1884
March	1st to 10th	Night	47% 4 9% 25% 12% 2	3577
	11th to 20th	Night	33% 6% 10% 32% 16% 3	3480
	21st to end	Night	41% 4 8% 20% 22% 5%	3690
April	1st to 10th	Night	44% 3 10% 20% 18% 4	1900
	11th to 20th	Night	38% 5% 12% 21% 19% 5%	1875
	21st to end	Night	40% 6% 10% 22% 18% 5%	1850
May	1st to 10th	Night	44% 5% 11% 20% 16% 4	1684
	11th to 20th	Night	46% 6% 12% 15% 19% 2	1416
	21st to end	Night	37% 10% 17% 21% 12% 3	1551
June	1st to 10th	Night	37% 7% 12% 25% 18% 2	1440
	11th to 20th	Night	40% 6% 14% 23% 15% 1	1440
	21st to end	Night	34% 7% 13% 28% 15% 2	1440
July	1st to 10th	Night	41% 8% 16% 18% 13% 3	1400
	11th to 20th	Night	30% 9% 18% 24% 17% 2	1392
	21st to end	Night	33% 8% 16% 23% 18% 2	1633
August	1st to 10th	Night	36% 7% 17% 24% 15% 1	1600
	11th to 20th	Night	42% 7% 14% 20% 15% 2	1695
	21st to end	Night	38% 7% 13% 23% 16% 4	1980
September	1st to 10th	Night	40% 5% 11% 21% 19% 5%	1800
	11th to 20th	Night	32% 4 10% 25% 25% 4	1800
	21st to end	Night	42% 5% 9% 20% 21% 3	2038
October	1st to 10th	Night	43% 5% 11% 22% 18% 2	2160
	11th to 20th	Night	36% 4 11% 28% 19% 3	2160
	21st to end	Night	38% 4 10% 26% 20% 3	2376
November	1st to 10th	Night	33% 4 10% 27% 20% 5%	2389
	11th to 20th	Night	39% 3 9% 23% 20% 5%	2470
	21st to end	Night	37% 4 11% 27% 18% 2	2657
December	1st to 10th	Night	46% 4 12% 23% 14% 1	2660
	11th to 20th	Night	41% 5% 11% 22% 17% 3	3288
	21st to end	Night	44% 7% 15% 22% 10% 1	4884

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	30% 27% 27% 13% 2 1	180
	11th to 20th	Day	36% 24% 26% 13% 1	247
	21st to end	Day	24% 33% 30% 10% 3	297
February	1st to 10th	Day	26% 27% 35% 9% 2 1	270
	11th to 20th	Day	35% 25% 35% 5% 1	350
	21st to end	Day	36% 22% 27% 13% 2	382
March	1st to 10th	Day	27% 24% 30% 16% 3	460
	11th to 20th	Day	28% 24% 32% 12% 3 1	460
	21st to end	Day	26% 24% 31% 14% 4 1	506
April	1st to 10th	Day	24% 25% 35% 11% 5% 1	460
	11th to 20th	Day	22% 21% 30% 17% 7% 2	452
	21st to end	Day	28% 18% 34% 13% 5% 2	437
May	1st to 10th	Day	28% 18% 30% 14% 8% 2	423
	11th to 20th	Day	24% 16% 30% 21% 7% 2	447
	21st to end	Day	20% 8% 23% 27% 18% 4	485
June	1st to 10th	Day	15% 11% 32% 26% 12% 4	450
	11th to 20th	Day	18% 10% 29% 27% 13% 3	450
	21st to end	Day	13% 10% 32% 29% 12% 5%	450
July	1st to 10th	Day	13% 4 20% 31% 23% 8%	445
	11th to 20th	Day	5% 4 25% 36% 23% 7%	444
	21st to end	Day	14% 6% 26% 31% 19% 5%	488
August	1st to 10th	Day	11% 4 26% 32% 20% 7%	446
	11th to 20th	Day	10% 7% 18% 35% 20% 10%	439
	21st to end	Day	12% 5% 25% 31% 18% 9%	495
September	1st to 10th	Day	21% 6% 21% 25% 19% 9%	450
	11th to 20th	Day	16% 7% 24% 27% 17% 9%	450
	21st to end	Day	27% 9% 24% 25% 12% 4	450
October	1st to 10th	Day	25% 7% 23% 25% 13% 7%	450
	11th to 20th	Day	21% 14% 28% 23% 13% 1	450
	21st to end	Day	19% 18% 37% 17% 7% 2	495
November	1st to 10th	Day	19% 14% 32% 22% 11% 2	373
	11th to 20th	Day	20% 21% 32% 19% 7% 1	370
	21st to end	Day	27% 19% 32% 17% 4 1	180
December	1st to 10th	Day	26% 24% 33% 12% 3 1	180
	11th to 20th	Day	29% 26% 29% 12% 3	180
	21st to end	Day	26% 19% 33% 15% 7%	198
January	1st to 10th	Night	22% 20% 38% 17% 3	760
	11th to 20th	Night	26% 18% 32% 21% 3	760
	21st to end	Night	20% 23% 38% 19% 1	836
February	1st to 10th	Night	23% 19% 34% 21% 3	760
	11th to 20th	Night	26% 24% 34% 14% 1	743
	21st to end	Night	24% 24% 33% 16% 3	628
March	1st to 10th	Night	22% 22% 35% 17% 4	760
	11th to 20th	Night	23% 23% 32% 17% 5%	760
	21st to end	Night	22% 18% 38% 17% 4	836
April	1st to 10th	Night	22% 22% 35% 18% 3	760
	11th to 20th	Night	19% 16% 35% 24% 6%	751
	21st to end	Night	24% 15% 30% 24% 7%	740
May	1st to 10th	Night	23% 11% 31% 28% 7% 1	604
	11th to 20th	Night	22% 11% 30% 29% 8%	354
	21st to end	Night	19% 5% 21% 38% 17% 2	389
June	1st to 10th	Night	14% 2 28% 39% 16% 1	360
	11th to 20th	Night	12% 5% 28% 40% 15% 1	360
	21st to end	Night	11% 3 25% 44% 17%	360
July	1st to 10th	Night	11% 4 19% 38% 26% 3	350
	11th to 20th	Night	7% 3 18% 40% 28% 3	348
	21st to end	Night	8% 3 20% 45% 22% 3	549
August	1st to 10th	Night	12% 2 16% 42% 25% 2	537
	11th to 20th	Night	15% 4 15% 35% 28% 2	631
	21st to end	Night	14% 4 16% 39% 24% 4	792
September	1st to 10th	Night	17% 5% 21% 32% 22% 4	720
	11th to 20th	Night	15% 5% 18% 33% 25% 5%	720
	21st to end	Night	20% 6% 24% 31% 18% 2	720
October	1st to 10th	Night	24% 8% 21% 26% 17% 5%	720
	11th to 20th	Night	19% 12% 26% 30% 12% 1	720
	21st to end	Night	21% 14% 31% 22% 11%	792
November	1st to 10th	Night	15% 13% 34% 28% 10% 1	740
	11th to 20th	Night	20% 19% 30% 23% 7% 1	760
	21st to end	Night	17% 19% 32% 25% 7%	760
December	1st to 10th	Night	24% 19% 33% 17% 7%	760
	11th to 20th	Night	19% 18% 38% 20% 4	760
	21st to end	Night	21% 19% 32% 25% 3	836

Page generated at 2024-04-22 09:25:40. Version ac07

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