Kile Knob Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kile Knob Observatory clear sky chart from 2005-11-06 to 2025-01-07.

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	12% 8% 3 8% 5% 5% 5% 4 6% 7% 36%	104624
	Night	11% 7% 3 7% 5% 5% 5% 4 6% 8% 38%	104328
Transparency	Day	24% 45% 7% 14% 8% 2	108274
	Night	24% 45% 8% 14% 8% 2	108817
Seeing	Day	22% 16% 26% 20% 11% 4	15101
	Night	20% 15% 25% 27% 12% 1	25029

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	11% 10% 3 9% 7% 5% 5% 4 5% 6% 35%	2890
	11th to 20th	Day	8% 13% 7% 12% 7% 7% 5% 3 4 4 29%	2840
	21st to end	Day	11% 12% 5% 10% 5% 4 5% 3 5% 6% 34%	3124
February	1st to 10th	Day	9% 10% 3 8% 6% 6% 6% 4 5% 8% 35%	1710
	11th to 20th	Day	10% 9% 4 10% 5% 5% 4 4 6% 7% 36%	1663
	21st to end	Day	10% 11% 4 8% 5% 5% 4 3 6% 6% 38%	1628
March	1st to 10th	Day	15% 8% 5% 8% 5% 5% 4 4 6% 7% 34%	3435
	11th to 20th	Day	8% 8% 2 8% 5% 4 4 4 5% 6% 46%	3480
	21st to end	Day	13% 10% 3 8% 6% 5% 5% 4 5% 5% 36%	3815
April	1st to 10th	Day	9% 8% 4 8% 7% 6% 5% 3 6% 7% 38%	2199
	11th to 20th	Day	12% 8% 3 7% 4 4 4 4 5% 7% 42%	2254
	21st to end	Day	16% 8% 2 7% 5% 5% 4 4 6% 6% 36%	2403
May	1st to 10th	Day	18% 9% 3 9% 6% 5% 6% 4 6% 6% 28%	4082
	11th to 20th	Day	22% 9% 3 7% 4 4 5% 4 6% 7% 30%	4081
	21st to end	Day	10% 6% 3 8% 6% 6% 7% 5% 8% 9% 33%	4562
June	1st to 10th	Day	13% 6% 2 6% 5% 5% 6% 5% 7% 7% 38%	2660
	11th to 20th	Day	11% 7% 2 6% 6% 6% 6% 5% 7% 9% 34%	2660
	21st to end	Day	8% 5% 3 7% 6% 6% 7% 5% 7% 9% 37%	2640
July	1st to 10th	Day	7% 6% 2 8% 6% 7% 7% 5% 7% 9% 37%	4120
	11th to 20th	Day	9% 5% 2 7% 6% 5% 6% 5% 8% 10% 36%	4120
	21st to end	Day	12% 10% 4 10% 6% 6% 5% 5% 7% 8% 27%	4466
August	1st to 10th	Day	13% 6% 3 8% 6% 6% 7% 6% 7% 10% 28%	4104
	11th to 20th	Day	8% 5% 3 8% 7% 8% 8% 5% 8% 9% 31%	4044
	21st to end	Day	7% 5% 2 6% 5% 6% 6% 5% 6% 9% 43%	4212
September	1st to 10th	Day	14% 6% 2 6% 5% 6% 5% 4 5% 7% 40%	2280
	11th to 20th	Day	13% 6% 3 7% 4 5% 5% 4 5% 7% 41%	2122
	21st to end	Day	21% 7% 3 6% 5% 4 5% 3 5% 6% 35%	2069
October	1st to 10th	Day	15% 5% 2 6% 4 5% 5% 3 5% 7% 44%	1900
	11th to 20th	Day	14% 10% 3 6% 5% 4 3 3 4 5% 44%	1900
	21st to end	Day	12% 7% 3 6% 4 4 4 4 5% 7% 46%	2090
November	1st to 10th	Day	8% 7% 2 5% 3 4 4 4 6% 6% 50%	1957
	11th to 20th	Day	12% 7% 3 6% 4 4 5% 3 6% 7% 43%	1755
	21st to end	Day	11% 9% 3 7% 5% 4 5% 4 5% 6% 42%	1600
December	1st to 10th	Day	7% 7% 3 8% 5% 6% 4 4 5% 8% 44%	2600
	11th to 20th	Day	13% 8% 3 7% 4 5% 4 4 5% 7% 38%	2990
	21st to end	Day	14% 9% 3 9% 5% 5% 6% 4 7% 7% 30%	4169
January	1st to 10th	Night	8% 10% 6% 10% 7% 6% 6% 4 6% 6% 30%	4188
	11th to 20th	Night	10% 10% 3 10% 7% 4 5% 3 5% 6% 38%	4120
	21st to end	Night	13% 11% 4 7% 4 4 5% 4 5% 6% 36%	4532
February	1st to 10th	Night	8% 8% 3 7% 6% 5% 5% 5% 7% 9% 37%	2470
	11th to 20th	Night	11% 9% 3 8% 6% 5% 6% 5% 6% 6% 34%	2403
	21st to end	Night	11% 9% 3 9% 6% 5% 5% 4 6% 7% 36%	1822
March	1st to 10th	Night	18% 10% 3 7% 5% 5% 5% 4 6% 6% 30%	3418
	11th to 20th	Night	8% 7% 5% 9% 4 4 4 3 5% 7% 43%	3480
	21st to end	Night	11% 10% 2 6% 5% 3 4 4 5% 7% 43%	3817
April	1st to 10th	Night	9% 8% 4 7% 6% 5% 5% 4 5% 7% 40%	1979
	11th to 20th	Night	11% 7% 2 5% 5% 5% 4 4 5% 9% 42%	1875
	21st to end	Night	14% 6% 2 6% 5% 4 4 3 7% 7% 41%	1791
May	1st to 10th	Night	18% 9% 3 9% 5% 5% 5% 4 6% 7% 28%	2813
	11th to 20th	Night	22% 10% 2 6% 5% 4 3 3 5% 6% 33%	2812
	21st to end	Night	9% 5% 2 8% 5% 6% 6% 5% 7% 9% 37%	2986
June	1st to 10th	Night	10% 4 1 5% 4 5% 6% 5% 8% 10% 43%	1520
	11th to 20th	Night	9% 5% 2 5% 5% 5% 5% 5% 7% 11% 41%	1520
	21st to end	Night	7% 4 2 5% 5% 4 5% 4 8% 10% 46%	1531
July	1st to 10th	Night	6% 4 2 6% 4 5% 6% 5% 9% 11% 43%	2840
	11th to 20th	Night	8% 5% 3 8% 5% 5% 6% 4 7% 10% 40%	2840
	21st to end	Night	10% 8% 3 10% 6% 6% 6% 5% 7% 8% 32%	3087
August	1st to 10th	Night	15% 5% 2 7% 5% 5% 6% 5% 7% 9% 36%	2825
	11th to 20th	Night	9% 7% 3 7% 6% 7% 6% 4 7% 7% 38%	2785
	21st to end	Night	7% 4 2 6% 5% 5% 5% 4 6% 10% 47%	3411
September	1st to 10th	Night	13% 5% 2 6% 4 4 5% 5% 5% 7% 46%	1900
	11th to 20th	Night	12% 6% 2 6% 5% 4 4 3 5% 6% 46%	2055
	21st to end	Night	20% 7% 2 5% 5% 4 5% 4 5% 6% 38%	2109
October	1st to 10th	Night	15% 6% 2 5% 3 4 5% 4 5% 7% 44%	2280
	11th to 20th	Night	11% 7% 2 6% 4 4 4 3 5% 7% 46%	2280
	21st to end	Night	13% 6% 2 5% 4 4 4 4 5% 6% 46%	2508
November	1st to 10th	Night	7% 8% 2 6% 5% 4 5% 4 5% 7% 46%	2341
	11th to 20th	Night	11% 7% 3 6% 5% 4 5% 4 6% 7% 42%	2637
	21st to end	Night	10% 8% 2 7% 5% 5% 6% 4 6% 6% 40%	2800
December	1st to 10th	Night	7% 7% 2 8% 5% 5% 5% 4 7% 8% 42%	4580
	11th to 20th	Night	12% 9% 4 9% 5% 4 5% 4 6% 6% 36%	5205
	21st to end	Night	11% 6% 6% 9% 6% 6% 6% 5% 7% 9% 30%	6768

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	33% 36% 2 16% 10% 3	2891
	11th to 20th	Day	38% 36% 3 10% 10% 3	2840
	21st to end	Day	33% 39% 4 13% 11% 1	3124
February	1st to 10th	Day	17% 66% 4 7% 6% 1	1710
	11th to 20th	Day	18% 65% 3 6% 7% 1	1672
	21st to end	Day	18% 64% 4 6% 6% 1	1628
March	1st to 10th	Day	36% 41% 3 14% 6% 1	3435
	11th to 20th	Day	20% 39% 4 21% 15% 1	3480
	21st to end	Day	29% 40% 6% 13% 10% 2	3815
April	1st to 10th	Day	17% 66% 4 8% 5% 1	2199
	11th to 20th	Day	14% 66% 4 10% 5% 1	2254
	21st to end	Day	18% 65% 4 10% 3 1	2403
May	1st to 10th	Day	36% 40% 6% 14% 3	4120
	11th to 20th	Day	32% 40% 6% 16% 5%	4085
	21st to end	Day	26% 40% 9% 13% 8% 3	4576
June	1st to 10th	Day	16% 66% 4 9% 5%	2660
	11th to 20th	Day	15% 67% 6% 8% 4	2660
	21st to end	Day	16% 65% 6% 9% 4 1	2640
July	1st to 10th	Day	24% 40% 13% 14% 5% 4	4055
	11th to 20th	Day	24% 39% 11% 20% 5%	4051
	21st to end	Day	36% 37% 6% 14% 7%	4324
August	1st to 10th	Day	31% 41% 11% 13% 4	4091
	11th to 20th	Day	23% 40% 9% 19% 9%	4083
	21st to end	Day	18% 40% 12% 20% 10%	4212
September	1st to 10th	Day	16% 61% 7% 7% 7% 2	2280
	11th to 20th	Day	17% 60% 3 9% 8% 2	2122
	21st to end	Day	22% 60% 5% 9% 4	2069
October	1st to 10th	Day	15% 38% 6% 14% 22% 5%	3160
	11th to 20th	Day	16% 37% 5% 19% 11% 12%	3140
	21st to end	Day	13% 36% 6% 21% 14% 9%	3428
November	1st to 10th	Day	17% 57% 5% 11% 9% 2	1957
	11th to 20th	Day	14% 56% 4 9% 14% 3	1755
	21st to end	Day	18% 56% 5% 13% 7% 1	1600
December	1st to 10th	Day	21% 38% 7% 16% 15% 4	2600
	11th to 20th	Day	29% 32% 11% 13% 13% 2	2986
	21st to end	Day	37% 28% 11% 13% 11% 1	4169
January	1st to 10th	Night	35% 35% 3 14% 11% 2	4188
	11th to 20th	Night	30% 36% 5% 15% 10% 4	4120
	21st to end	Night	31% 39% 4 15% 10% 1	4532
February	1st to 10th	Night	14% 66% 7% 8% 4 1	2470
	11th to 20th	Night	18% 65% 2 8% 5% 1	2405
	21st to end	Night	17% 64% 5% 7% 5% 2	1822
March	1st to 10th	Night	38% 42% 4 11% 4 1	3418
	11th to 20th	Night	21% 39% 5% 20% 13% 1	3480
	21st to end	Night	23% 40% 7% 17% 11% 2	3817
April	1st to 10th	Night	15% 66% 5% 9% 5%	1979
	11th to 20th	Night	13% 67% 7% 9% 4 1	1875
	21st to end	Night	15% 65% 5% 11% 4	1791
May	1st to 10th	Night	35% 41% 8% 12% 3 1	2840
	11th to 20th	Night	34% 40% 7% 18% 2	2813
	21st to end	Night	25% 41% 12% 16% 3 3	2993
June	1st to 10th	Night	13% 67% 7% 10% 3	1520
	11th to 20th	Night	12% 67% 6% 10% 4	1520
	21st to end	Night	12% 66% 8% 10% 5%	1531
July	1st to 10th	Night	20% 42% 18% 12% 7% 2	2795
	11th to 20th	Night	26% 39% 14% 17% 4	2786
	21st to end	Night	33% 40% 10% 12% 5%	2988
August	1st to 10th	Night	29% 41% 13% 14% 2	2814
	11th to 20th	Night	24% 41% 13% 14% 8%	2812
	21st to end	Night	17% 38% 13% 24% 7%	3411
September	1st to 10th	Night	15% 61% 8% 9% 5% 2	1900
	11th to 20th	Night	18% 60% 4 11% 7%	2055
	21st to end	Night	22% 60% 5% 9% 4	2109
October	1st to 10th	Night	21% 38% 6% 17% 16% 3	3800
	11th to 20th	Night	17% 38% 7% 12% 18% 9%	3779
	21st to end	Night	11% 37% 8% 22% 16% 7%	4120
November	1st to 10th	Night	18% 56% 7% 10% 7% 2	2341
	11th to 20th	Night	15% 56% 3 10% 13% 3	2637
	21st to end	Night	17% 57% 6% 11% 7% 1	2800
December	1st to 10th	Night	21% 37% 10% 19% 12% 1	4580
	11th to 20th	Night	33% 33% 10% 10% 12% 2	5208
	21st to end	Night	36% 28% 10% 16% 10%	6768

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	38% 26% 23% 9% 3	288
	11th to 20th	Day	34% 26% 29% 9% 2	270
	21st to end	Day	36% 29% 27% 7% 1	297
February	1st to 10th	Day	35% 28% 29% 7% 1	270
	11th to 20th	Day	45% 29% 21% 5% 1	270
	21st to end	Day	40% 25% 26% 9%	310
March	1st to 10th	Day	30% 23% 28% 14% 5%	460
	11th to 20th	Day	33% 24% 21% 17% 4 1	460
	21st to end	Day	28% 23% 28% 16% 4 1	506
April	1st to 10th	Day	25% 31% 23% 16% 4 1	460
	11th to 20th	Day	25% 21% 26% 17% 8% 2	452
	21st to end	Day	29% 20% 28% 13% 7% 2	460
May	1st to 10th	Day	28% 20% 25% 13% 10% 3	463
	11th to 20th	Day	25% 15% 29% 18% 9% 3	487
	21st to end	Day	19% 10% 23% 28% 14% 6%	529
June	1st to 10th	Day	17% 13% 27% 24% 14% 5%	490
	11th to 20th	Day	17% 10% 30% 20% 17% 6%	490
	21st to end	Day	11% 12% 31% 30% 12% 4	490
July	1st to 10th	Day	9% 9% 25% 28% 21% 8%	485
	11th to 20th	Day	6% 6% 26% 35% 18% 9%	484
	21st to end	Day	13% 6% 25% 28% 20% 8%	532
August	1st to 10th	Day	13% 8% 23% 27% 19% 10%	486
	11th to 20th	Day	11% 5% 26% 27% 20% 11%	479
	21st to end	Day	10% 6% 21% 27% 23% 13%	539
September	1st to 10th	Day	16% 9% 19% 25% 20% 10%	490
	11th to 20th	Day	15% 6% 20% 28% 20% 11%	490
	21st to end	Day	28% 12% 20% 23% 14% 3	490
October	1st to 10th	Day	19% 9% 24% 27% 18% 3	490
	11th to 20th	Day	20% 18% 24% 24% 10% 3	490
	21st to end	Day	21% 17% 32% 21% 8% 1	539
November	1st to 10th	Day	18% 18% 32% 21% 11% 1	495
	11th to 20th	Day	27% 18% 29% 20% 6%	293
	21st to end	Day	34% 17% 33% 15% 2 1	200
December	1st to 10th	Day	31% 23% 32% 11% 3 1	200
	11th to 20th	Day	33% 21% 27% 14% 6%	200
	21st to end	Day	32% 21% 31% 10% 5%	267
January	1st to 10th	Night	29% 26% 29% 14% 3	785
	11th to 20th	Night	28% 21% 28% 21% 1	760
	21st to end	Night	24% 24% 35% 15% 2	836
February	1st to 10th	Night	24% 24% 31% 19% 1	760
	11th to 20th	Night	29% 28% 30% 13% 1	743
	21st to end	Night	27% 24% 34% 14% 1	628
March	1st to 10th	Night	24% 22% 33% 19% 3	760
	11th to 20th	Night	28% 21% 25% 20% 4 1	760
	21st to end	Night	23% 21% 30% 21% 5% 1	836
April	1st to 10th	Night	21% 22% 31% 22% 4	760
	11th to 20th	Night	19% 18% 29% 25% 8% 1	751
	21st to end	Night	20% 16% 29% 28% 7%	651
May	1st to 10th	Night	20% 10% 25% 30% 13% 2	570
	11th to 20th	Night	19% 8% 24% 34% 13% 1	561
	21st to end	Night	14% 5% 25% 33% 21% 3	562
June	1st to 10th	Night	11% 4 27% 36% 21% 2	380
	11th to 20th	Night	10% 5% 19% 46% 18% 1	380
	21st to end	Night	7% 5% 25% 46% 16% 1	391
July	1st to 10th	Night	12% 2 14% 42% 26% 5%	555
	11th to 20th	Night	6% 2 16% 42% 30% 4	552
	21st to end	Night	9% 4 16% 38% 30% 3	624
August	1st to 10th	Night	9% 2 15% 43% 30% 2	567
	11th to 20th	Night	11% 3 12% 41% 30% 3	564
	21st to end	Night	11% 4 16% 37% 29% 3	797
September	1st to 10th	Night	14% 4 14% 37% 25% 6%	760
	11th to 20th	Night	13% 7% 14% 33% 29% 4	760
	21st to end	Night	23% 7% 21% 28% 19% 2	760
October	1st to 10th	Night	20% 9% 18% 29% 21% 3	760
	11th to 20th	Night	18% 16% 25% 27% 13% 1	760
	21st to end	Night	21% 13% 28% 28% 9% 1	836
November	1st to 10th	Night	16% 14% 30% 29% 10% 1	780
	11th to 20th	Night	23% 16% 28% 24% 8% 1	800
	21st to end	Night	22% 20% 29% 23% 6% 1	800
December	1st to 10th	Night	25% 23% 27% 21% 4	800
	11th to 20th	Night	21% 23% 29% 24% 3 1	800
	21st to end	Night	23% 19% 30% 27% 2	880

Page generated at 2025-01-04 03:24:03. Version ac07

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