High Knob Overlook
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the High Knob Overlook clear sky chart from 2005-11-06 to 2024-12-24.

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	18% 10% 4 7% 5% 4 4 4 5% 7% 32%	101859
	Night	18% 11% 3 7% 5% 4 4 3 5% 6% 34%	98260
Transparency	Day	49% 7% 11% 21% 11% 1	105446
	Night	49% 7% 11% 20% 11% 1	102761
Seeing	Day	25% 18% 29% 18% 8% 2	14888
	Night	22% 18% 30% 22% 8% 1	24272

By Month

Percentage Cloud Cover NE (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	14% 18% 7% 9% 5% 5% 4 3 4 5% 27%	2517
	11th to 20th	Day	14% 16% 9% 16% 5% 4 3 3 4 4 20%	2648
	21st to end	Day	21% 17% 9% 10% 6% 3 3 3 3 4 20%	3124
February	1st to 10th	Day	17% 16% 5% 8% 6% 6% 5% 4 4 5% 25%	1710
	11th to 20th	Day	14% 13% 5% 9% 6% 5% 5% 4 5% 6% 28%	1696
	21st to end	Day	19% 14% 4 9% 6% 4 4 3 5% 6% 28%	1570
March	1st to 10th	Day	24% 13% 4 8% 4 4 4 2 3 4 29%	3266
	11th to 20th	Day	11% 13% 5% 8% 5% 4 3 3 5% 5% 36%	3480
	21st to end	Day	17% 13% 3 7% 4 3 3 3 5% 6% 36%	3937
April	1st to 10th	Day	18% 13% 3 9% 4 4 4 3 4 6% 32%	2280
	11th to 20th	Day	18% 11% 3 7% 5% 4 4 4 5% 6% 33%	2254
	21st to end	Day	19% 8% 3 7% 4 4 5% 4 5% 6% 35%	2287
May	1st to 10th	Day	28% 8% 3 6% 4 4 4 3 5% 6% 31%	4231
	11th to 20th	Day	25% 9% 3 8% 5% 5% 5% 3 5% 6% 25%	4398
	21st to end	Day	16% 6% 2 5% 4 4 4 4 6% 9% 40%	4837
June	1st to 10th	Day	15% 6% 2 6% 6% 5% 6% 4 6% 8% 34%	2660
	11th to 20th	Day	16% 7% 2 6% 5% 5% 5% 5% 6% 7% 35%	2660
	21st to end	Day	14% 6% 2 6% 5% 4 6% 5% 7% 9% 36%	2660
July	1st to 10th	Day	9% 6% 3 7% 6% 6% 6% 5% 7% 10% 36%	4440
	11th to 20th	Day	9% 5% 3 7% 5% 6% 6% 4 9% 10% 37%	4440
	21st to end	Day	13% 7% 3 8% 6% 6% 6% 4 7% 7% 34%	4661
August	1st to 10th	Day	21% 8% 3 8% 5% 5% 4 4 5% 8% 30%	4104
	11th to 20th	Day	17% 7% 2 7% 5% 5% 6% 5% 7% 9% 31%	3921
	21st to end	Day	18% 5% 2 5% 4 4 5% 4 7% 8% 39%	4180
September	1st to 10th	Day	17% 6% 2 6% 4 4 4 3 4 9% 40%	2280
	11th to 20th	Day	15% 5% 2 5% 4 3 4 4 5% 6% 46%	2280
	21st to end	Day	24% 8% 3 5% 4 3 3 3 5% 6% 35%	2013
October	1st to 10th	Day	20% 8% 2 5% 4 4 4 4 5% 7% 39%	1900
	11th to 20th	Day	22% 8% 2 7% 4 4 5% 3 5% 6% 35%	1900
	21st to end	Day	21% 11% 3 6% 5% 4 4 4 5% 6% 31%	2072
November	1st to 10th	Day	14% 9% 2 7% 4 4 4 4 5% 6% 41%	1761
	11th to 20th	Day	17% 13% 3 7% 5% 3 4 4 5% 5% 33%	1710
	21st to end	Day	19% 13% 3 6% 5% 4 4 5% 5% 6% 30%	1600
December	1st to 10th	Day	21% 14% 6% 11% 6% 5% 4 3 4 5% 23%	1600
	11th to 20th	Day	22% 14% 5% 7% 3 4 4 2 5% 6% 28%	1986
	21st to end	Day	21% 18% 7% 11% 5% 5% 4 3 4 5% 19%	2796
January	1st to 10th	Night	15% 15% 5% 9% 5% 4 4 3 5% 6% 28%	4429
	11th to 20th	Night	15% 16% 7% 13% 5% 4 3 4 4 5% 24%	4312
	21st to end	Night	21% 14% 6% 12% 7% 4 4 3 4 5% 21%	4532
February	1st to 10th	Night	15% 13% 4 8% 6% 5% 5% 4 5% 6% 29%	2470
	11th to 20th	Night	14% 12% 5% 10% 6% 5% 5% 4 5% 6% 29%	2368
	21st to end	Night	17% 13% 3 10% 6% 4 4 3 5% 5% 29%	1884
March	1st to 10th	Night	22% 17% 3 6% 4 3 3 3 4 5% 29%	3571
	11th to 20th	Night	12% 15% 6% 8% 4 4 4 4 5% 6% 32%	3479
	21st to end	Night	15% 12% 2 7% 5% 4 3 3 4 4 40%	3694
April	1st to 10th	Night	19% 14% 3 7% 5% 4 4 3 5% 7% 30%	1900
	11th to 20th	Night	18% 8% 3 6% 4 4 4 4 5% 7% 37%	1875
	21st to end	Night	18% 6% 3 6% 4 4 4 3 5% 6% 40%	1900
May	1st to 10th	Night	30% 9% 2 6% 4 3 3 2 4 6% 30%	2717
	11th to 20th	Night	25% 11% 2 6% 4 4 5% 4 4 6% 29%	2495
	21st to end	Night	16% 7% 2 6% 4 4 4 3 6% 8% 39%	2738
June	1st to 10th	Night	16% 6% 2 6% 4 3 5% 4 5% 7% 42%	1520
	11th to 20th	Night	13% 7% 2 6% 5% 5% 5% 4 6% 9% 38%	1520
	21st to end	Night	14% 5% 2 5% 4 4 5% 4 7% 8% 41%	1520
July	1st to 10th	Night	11% 6% 3 7% 4 4 4 4 6% 8% 42%	2520
	11th to 20th	Night	12% 5% 2 5% 4 4 5% 4 7% 10% 41%	2520
	21st to end	Night	16% 6% 2 6% 4 3 4 3 5% 7% 42%	2888
August	1st to 10th	Night	21% 7% 2 7% 4 4 4 4 5% 7% 34%	2825
	11th to 20th	Night	19% 7% 3 5% 4 3 3 2 4 6% 43%	2876
	21st to end	Night	14% 5% 2 5% 3 4 4 4 6% 8% 45%	3476
September	1st to 10th	Night	16% 6% 2 6% 4 4 4 3 4 6% 44%	1900
	11th to 20th	Night	14% 5% 2 5% 3 3 3 3 4 7% 50%	1900
	21st to end	Night	20% 7% 2 6% 4 4 3 3 5% 6% 40%	2163
October	1st to 10th	Night	20% 8% 3 6% 4 3 3 3 5% 5% 42%	2280
	11th to 20th	Night	19% 8% 3 6% 4 3 3 3 4 5% 41%	2280
	21st to end	Night	22% 10% 3 7% 4 3 4 3 4 7% 34%	2524
November	1st to 10th	Night	12% 9% 3 5% 4 4 4 3 5% 6% 44%	2537
	11th to 20th	Night	19% 12% 3 7% 5% 4 4 4 5% 6% 32%	2686
	21st to end	Night	16% 14% 3 7% 5% 4 4 3 6% 6% 31%	2800
December	1st to 10th	Night	19% 14% 5% 9% 5% 5% 4 3 5% 6% 24%	2800
	11th to 20th	Night	20% 13% 4 9% 6% 5% 4 3 4 5% 27%	3428
	21st to end	Night	22% 15% 6% 8% 5% 4 4 3 5% 6% 21%	4933

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	56% 9% 11% 17% 5% 2	2518
	11th to 20th	Day	67% 5% 6% 14% 6% 1	2648
	21st to end	Day	68% 6% 7% 14% 5% 1	3124
February	1st to 10th	Day	61% 6% 10% 14% 8% 1	1710
	11th to 20th	Day	56% 6% 7% 22% 8% 1	1705
	21st to end	Day	57% 6% 8% 19% 8% 2	1570
March	1st to 10th	Day	57% 7% 9% 19% 7% 1	3269
	11th to 20th	Day	46% 8% 14% 21% 9% 3	3480
	21st to end	Day	49% 6% 8% 18% 17% 2	3937
April	1st to 10th	Day	53% 6% 8% 19% 10% 3	2280
	11th to 20th	Day	49% 7% 10% 19% 13% 2	2254
	21st to end	Day	47% 7% 9% 20% 14% 3	2287
May	1st to 10th	Day	53% 5% 9% 22% 9% 1	4243
	11th to 20th	Day	56% 9% 11% 16% 6% 1	4402
	21st to end	Day	36% 10% 13% 25% 14% 1	4837
June	1st to 10th	Day	45% 9% 12% 20% 13% 1	2660
	11th to 20th	Day	46% 9% 13% 20% 11% 1	2660
	21st to end	Day	41% 9% 14% 25% 11%	2660
July	1st to 10th	Day	41% 9% 15% 24% 11%	4370
	11th to 20th	Day	38% 9% 18% 23% 12%	4365
	21st to end	Day	46% 8% 12% 20% 13% 1	4512
August	1st to 10th	Day	52% 7% 13% 18% 9%	4091
	11th to 20th	Day	46% 9% 13% 25% 7%	3960
	21st to end	Day	40% 7% 11% 32% 9% 1	4180
September	1st to 10th	Day	42% 6% 12% 23% 15% 2	2280
	11th to 20th	Day	37% 6% 12% 22% 21% 2	2280
	21st to end	Day	49% 6% 10% 18% 15% 1	2013
October	1st to 10th	Day	42% 6% 9% 22% 19% 3	3160
	11th to 20th	Day	44% 5% 7% 25% 15% 5%	3140
	21st to end	Day	37% 4 15% 28% 14% 1	3398
November	1st to 10th	Day	43% 7% 12% 20% 16% 3	1761
	11th to 20th	Day	51% 7% 10% 19% 11% 2	1710
	21st to end	Day	53% 8% 12% 20% 7% 1	1600
December	1st to 10th	Day	65% 4 11% 12% 7% 1	1600
	11th to 20th	Day	58% 6% 13% 18% 5%	1986
	21st to end	Day	67% 6% 9% 13% 5%	2796
January	1st to 10th	Night	55% 8% 10% 18% 7% 1	4429
	11th to 20th	Night	60% 8% 10% 14% 6% 1	4312
	21st to end	Night	65% 7% 7% 13% 7% 1	4532
February	1st to 10th	Night	54% 7% 10% 19% 9% 1	2470
	11th to 20th	Night	55% 7% 9% 17% 10% 1	2370
	21st to end	Night	55% 5% 9% 18% 11% 2	1884
March	1st to 10th	Night	57% 6% 9% 17% 9% 1	3581
	11th to 20th	Night	48% 10% 14% 20% 8% 1	3480
	21st to end	Night	46% 7% 8% 19% 17% 4	3694
April	1st to 10th	Night	54% 5% 10% 18% 11% 2	1900
	11th to 20th	Night	46% 7% 11% 20% 14% 1	1875
	21st to end	Night	44% 7% 11% 20% 16% 2	1900
May	1st to 10th	Night	55% 5% 9% 22% 7% 2	2724
	11th to 20th	Night	54% 9% 13% 15% 8% 1	2496
	21st to end	Night	39% 11% 14% 18% 15% 3	2739
June	1st to 10th	Night	41% 7% 12% 25% 14% 1	1520
	11th to 20th	Night	39% 9% 15% 26% 10% 2	1520
	21st to end	Night	38% 9% 13% 27% 12% 1	1520
July	1st to 10th	Night	39% 7% 14% 22% 16% 1	2480
	11th to 20th	Night	37% 8% 16% 25% 13% 1	2472
	21st to end	Night	40% 8% 13% 19% 19% 1	2796
August	1st to 10th	Night	48% 8% 15% 21% 7% 1	2814
	11th to 20th	Night	43% 5% 14% 26% 13%	2903
	21st to end	Night	36% 7% 12% 33% 11% 1	3476
September	1st to 10th	Night	41% 7% 10% 25% 15% 2	1900
	11th to 20th	Night	34% 5% 12% 26% 21% 2	1900
	21st to end	Night	45% 5% 11% 23% 16% 1	2163
October	1st to 10th	Night	45% 6% 10% 21% 18% 1	3800
	11th to 20th	Night	37% 5% 11% 24% 17% 7%	3779
	21st to end	Night	37% 4 15% 26% 15% 2	4148
November	1st to 10th	Night	40% 7% 12% 23% 16% 3	2537
	11th to 20th	Night	52% 6% 10% 18% 11% 3	2686
	21st to end	Night	51% 7% 14% 21% 7% 1	2800
December	1st to 10th	Night	59% 8% 11% 16% 5%	2800
	11th to 20th	Night	59% 5% 11% 16% 9%	3428
	21st to end	Night	61% 9% 10% 15% 4	4933

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	31% 27% 31% 9% 1 1	180
	11th to 20th	Day	40% 28% 26% 4	216
	21st to end	Day	27% 31% 30% 9% 2	297
February	1st to 10th	Day	38% 28% 29% 5%	270
	11th to 20th	Day	34% 31% 32% 4	303
	21st to end	Day	36% 26% 30% 8% 1	382
March	1st to 10th	Day	34% 25% 27% 11% 2	460
	11th to 20th	Day	30% 27% 29% 11% 2 1	460
	21st to end	Day	34% 25% 26% 10% 3 2	506
April	1st to 10th	Day	31% 27% 27% 11% 4	460
	11th to 20th	Day	26% 30% 24% 12% 6% 2	452
	21st to end	Day	27% 23% 33% 12% 3 2	460
May	1st to 10th	Day	33% 16% 30% 11% 8% 2	463
	11th to 20th	Day	26% 17% 31% 16% 8% 2	487
	21st to end	Day	21% 14% 28% 21% 14% 3	529
June	1st to 10th	Day	20% 16% 32% 23% 9% 1	490
	11th to 20th	Day	18% 15% 30% 26% 10% 1	490
	21st to end	Day	17% 13% 38% 22% 9% 1	490
July	1st to 10th	Day	14% 9% 30% 29% 14% 4	485
	11th to 20th	Day	9% 9% 31% 32% 14% 5%	484
	21st to end	Day	14% 9% 35% 27% 12% 3	532
August	1st to 10th	Day	15% 10% 26% 28% 17% 5%	486
	11th to 20th	Day	16% 7% 27% 30% 13% 6%	479
	21st to end	Day	17% 9% 27% 26% 12% 8%	539
September	1st to 10th	Day	21% 10% 25% 22% 16% 6%	490
	11th to 20th	Day	14% 9% 27% 23% 19% 8%	490
	21st to end	Day	27% 12% 29% 18% 11% 4	490
October	1st to 10th	Day	26% 12% 25% 22% 12% 4	490
	11th to 20th	Day	25% 16% 34% 17% 7% 1	490
	21st to end	Day	29% 21% 28% 16% 5%	529
November	1st to 10th	Day	24% 22% 28% 19% 6% 1	395
	11th to 20th	Day	28% 25% 30% 14% 3	310
	21st to end	Day	35% 25% 33% 7% 1	200
December	1st to 10th	Day	35% 30% 25% 8% 3 1	200
	11th to 20th	Day	38% 27% 27% 9%	200
	21st to end	Day	33% 26% 35% 5% 1	204
January	1st to 10th	Night	22% 28% 38% 10% 3	760
	11th to 20th	Night	23% 24% 34% 16% 2	760
	21st to end	Night	21% 29% 35% 14% 1	836
February	1st to 10th	Night	24% 26% 35% 14% 1	760
	11th to 20th	Night	24% 29% 37% 9% 1	743
	21st to end	Night	30% 22% 34% 13% 1	628
March	1st to 10th	Night	25% 27% 32% 14% 2	760
	11th to 20th	Night	27% 24% 30% 15% 4	760
	21st to end	Night	24% 25% 33% 12% 5%	836
April	1st to 10th	Night	24% 25% 31% 16% 3	760
	11th to 20th	Night	22% 23% 32% 17% 6%	751
	21st to end	Night	23% 19% 32% 21% 5%	760
May	1st to 10th	Night	28% 14% 25% 24% 9%	506
	11th to 20th	Night	18% 11% 37% 25% 8% 1	374
	21st to end	Night	18% 9% 28% 30% 14% 1	411
June	1st to 10th	Night	16% 8% 27% 35% 14% 1	380
	11th to 20th	Night	15% 7% 27% 38% 12%	380
	21st to end	Night	14% 5% 33% 38% 9% 1	380
July	1st to 10th	Night	12% 5% 26% 38% 17% 2	370
	11th to 20th	Night	11% 2 27% 39% 19% 2	368
	21st to end	Night	15% 5% 19% 43% 18% 1	503
August	1st to 10th	Night	14% 2 21% 43% 19% 1	567
	11th to 20th	Night	15% 5% 16% 36% 25% 3	616
	21st to end	Night	13% 6% 22% 36% 21% 3	836
September	1st to 10th	Night	16% 9% 24% 32% 16% 2	760
	11th to 20th	Night	15% 8% 22% 27% 24% 4	760
	21st to end	Night	22% 10% 23% 27% 15% 3	760
October	1st to 10th	Night	23% 12% 24% 23% 17% 2	760
	11th to 20th	Night	23% 13% 31% 25% 7% 1	760
	21st to end	Night	27% 15% 32% 20% 5%	836
November	1st to 10th	Night	17% 20% 34% 23% 6%	780
	11th to 20th	Night	26% 20% 30% 18% 4 1	800
	21st to end	Night	24% 21% 34% 18% 3 1	800
December	1st to 10th	Night	26% 24% 32% 14% 4	800
	11th to 20th	Night	23% 25% 33% 16% 3	800
	21st to end	Night	27% 24% 35% 12% 2	851

Page generated at 2024-12-21 04:13:53. Version ac07

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