Stokesville Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Stokesville Observatory clear sky chart from 2005-11-06 to 2024-10-24.

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	12% 6% 2 6% 5% 5% 5% 4 6% 8% 40%	100799
	Night	13% 6% 2 6% 4 4 4 4 6% 7% 44%	97879
Transparency	Day	41% 7% 12% 22% 15% 4	100611
	Night	39% 6% 12% 23% 16% 3	97737
Seeing	Day	17% 12% 24% 25% 16% 6%	14935
	Night	16% 8% 25% 33% 15% 2	24740

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 6% 6% 5% 4 4 4 5% 44%	2836
	11th to 20th	Day	12% 10% 2 9% 6% 5% 4 4 5% 5% 38%	2840
	21st to end	Day	14% 10% 3 8% 4 4 4 3 5% 5% 40%	3124
February	1st to 10th	Day	11% 7% 3 7% 5% 5% 5% 4 6% 6% 41%	1710
	11th to 20th	Day	13% 8% 3 7% 4 3 4 5% 5% 7% 42%	1663
	21st to end	Day	14% 8% 2 6% 4 4 4 4 6% 7% 41%	1633
March	1st to 10th	Day	17% 9% 3 6% 5% 4 4 4 5% 6% 36%	3435
	11th to 20th	Day	8% 6% 2 5% 4 3 4 3 6% 6% 52%	3480
	21st to end	Day	14% 9% 3 7% 5% 5% 5% 4 5% 5% 39%	3815
April	1st to 10th	Day	9% 6% 2 6% 5% 4 6% 4 6% 7% 45%	2213
	11th to 20th	Day	13% 5% 2 5% 5% 4 4 4 5% 7% 46%	2254
	21st to end	Day	16% 6% 2 6% 5% 5% 4 3 5% 7% 41%	2369
May	1st to 10th	Day	16% 7% 3 8% 6% 6% 6% 4 7% 8% 29%	4082
	11th to 20th	Day	22% 7% 3 7% 5% 4 5% 3 5% 6% 34%	4081
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 5% 8% 10% 40%	4601
June	1st to 10th	Day	11% 4 2 6% 5% 6% 6% 4 7% 9% 41%	2660
	11th to 20th	Day	9% 5% 2 6% 6% 5% 6% 6% 7% 10% 36%	2660
	21st to end	Day	7% 5% 2 6% 6% 5% 6% 5% 7% 11% 41%	2660
July	1st to 10th	Day	6% 5% 2 6% 6% 5% 6% 5% 7% 10% 41%	4124
	11th to 20th	Day	8% 5% 2 6% 6% 6% 7% 5% 9% 11% 35%	4120
	21st to end	Day	11% 8% 3 9% 6% 6% 6% 5% 7% 9% 29%	4466
August	1st to 10th	Day	12% 4 2 8% 6% 6% 6% 6% 8% 10% 32%	4104
	11th to 20th	Day	8% 4 2 7% 5% 6% 7% 5% 9% 9% 37%	4026
	21st to end	Day	8% 4 2 5% 5% 5% 5% 5% 6% 10% 45%	4180
September	1st to 10th	Day	12% 7% 2 6% 4 4 4 4 5% 6% 45%	2280
	11th to 20th	Day	14% 7% 2 5% 4 5% 5% 4 5% 7% 43%	2148
	21st to end	Day	23% 5% 2 6% 4 4 4 4 6% 6% 37%	2054
October	1st to 10th	Day	15% 5% 2 5% 3 4 4 4 5% 7% 45%	1900
	11th to 20th	Day	15% 4 1 5% 3 4 4 3 5% 6% 50%	1900
	21st to end	Day	14% 5% 2 4 5% 3 3 4 3 6% 51%	2010
November	1st to 10th	Day	10% 6% 2 4 3 4 3 3 5% 6% 55%	1857
	11th to 20th	Day	13% 5% 2 5% 3 4 4 3 6% 5% 50%	1682
	21st to end	Day	13% 5% 2 5% 4 4 3 3 5% 6% 50%	1520
December	1st to 10th	Day	14% 6% 3 8% 5% 4 5% 4 6% 7% 39%	1520
	11th to 20th	Day	14% 4 1 4 4 4 3 2 4 7% 53%	1910
	21st to end	Day	16% 6% 3 7% 4 5% 5% 5% 6% 7% 35%	2882
January	1st to 10th	Night	10% 7% 2 5% 4 4 5% 4 6% 6% 46%	4109
	11th to 20th	Night	14% 9% 2 5% 4 4 4 2 5% 5% 45%	4120
	21st to end	Night	17% 9% 3 6% 4 4 4 3 5% 5% 42%	4532
February	1st to 10th	Night	10% 7% 2 5% 4 4 4 5% 6% 8% 44%	2470
	11th to 20th	Night	16% 7% 2 6% 4 4 4 3 5% 7% 41%	2403
	21st to end	Night	14% 7% 2 6% 4 4 4 4 6% 8% 41%	1817
March	1st to 10th	Night	19% 7% 3 7% 4 4 4 4 6% 6% 36%	3418
	11th to 20th	Night	9% 4 2 5% 4 5% 4 4 5% 7% 51%	3480
	21st to end	Night	14% 7% 2 5% 3 3 3 3 5% 6% 48%	3817
April	1st to 10th	Night	13% 7% 2 4 4 5% 5% 4 6% 6% 44%	1965
	11th to 20th	Night	11% 4 2 5% 4 5% 4 3 7% 8% 47%	1875
	21st to end	Night	16% 4 2 5% 4 4 4 4 6% 7% 44%	1826
May	1st to 10th	Night	18% 7% 2 6% 5% 5% 5% 4 6% 9% 33%	2813
	11th to 20th	Night	23% 7% 3 6% 4 3 4 4 5% 6% 35%	2812
	21st to end	Night	10% 5% 1 6% 4 4 5% 5% 6% 11% 44%	2935
June	1st to 10th	Night	9% 5% 2 5% 5% 3 4 4 8% 12% 43%	1520
	11th to 20th	Night	10% 5% 2 5% 4 4 6% 5% 7% 10% 44%	1520
	21st to end	Night	8% 4 2 5% 4 3 6% 5% 7% 10% 46%	1520
July	1st to 10th	Night	6% 4 1 5% 5% 4 5% 4 8% 11% 45%	2829
	11th to 20th	Night	7% 7% 3 6% 5% 5% 6% 5% 8% 11% 38%	2840
	21st to end	Night	9% 8% 3 9% 7% 6% 5% 4 6% 10% 34%	3087
August	1st to 10th	Night	15% 5% 2 6% 5% 5% 4 5% 7% 10% 37%	2825
	11th to 20th	Night	9% 6% 3 7% 5% 5% 6% 5% 7% 8% 39%	2785
	21st to end	Night	9% 4 2 6% 4 4 4 4 6% 9% 48%	3460
September	1st to 10th	Night	12% 5% 2 6% 4 4 4 4 4 7% 49%	1900
	11th to 20th	Night	14% 6% 2 6% 4 4 4 3 5% 7% 46%	2028
	21st to end	Night	23% 6% 2 5% 3 3 4 3 5% 6% 40%	2125
October	1st to 10th	Night	16% 6% 2 5% 4 4 4 2 4 6% 46%	2280
	11th to 20th	Night	13% 5% 1 5% 4 3 4 3 5% 6% 51%	2280
	21st to end	Night	14% 3 1 4 4 3 4 3 5% 6% 52%	2413
November	1st to 10th	Night	11% 7% 3 4 4 4 3 3 4 5% 53%	2221
	11th to 20th	Night	12% 6% 1 5% 3 3 4 3 4 7% 51%	2493
	21st to end	Night	14% 5% 2 4 4 3 4 4 6% 6% 49%	2660
December	1st to 10th	Night	14% 7% 3 7% 4 4 5% 4 5% 5% 43%	2660
	11th to 20th	Night	13% 6% 3 6% 4 4 4 3 4 6% 47%	3285
	21st to end	Night	15% 5% 2 6% 5% 4 5% 4 7% 8% 38%	4756

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	42% 4 8% 22% 18% 6%	2837
	11th to 20th	Day	47% 4 8% 17% 18% 7%	2840
	21st to end	Day	47% 4 7% 21% 18% 3	3124
February	1st to 10th	Day	43% 5% 10% 21% 17% 4	1710
	11th to 20th	Day	42% 5% 11% 20% 18% 5%	1672
	21st to end	Day	43% 6% 11% 17% 18% 6%	1633
March	1st to 10th	Day	49% 5% 10% 19% 13% 5%	3435
	11th to 20th	Day	32% 6% 8% 26% 20% 8%	3480
	21st to end	Day	47% 7% 9% 19% 14% 4	3815
April	1st to 10th	Day	37% 7% 12% 19% 18% 8%	2213
	11th to 20th	Day	37% 6% 11% 21% 20% 5%	2254
	21st to end	Day	43% 7% 11% 22% 14% 4	2369
May	1st to 10th	Day	50% 9% 10% 20% 10% 1	4120
	11th to 20th	Day	51% 7% 10% 21% 10% 1	4085
	21st to end	Day	36% 9% 15% 21% 16% 3	4615
June	1st to 10th	Day	38% 8% 14% 24% 15% 1	2660
	11th to 20th	Day	40% 10% 15% 20% 14% 2	2660
	21st to end	Day	36% 8% 15% 25% 13% 2	2660
July	1st to 10th	Day	36% 10% 17% 21% 9% 6%	4059
	11th to 20th	Day	38% 10% 16% 27% 8% 1	4051
	21st to end	Day	49% 9% 11% 21% 10% 1	4324
August	1st to 10th	Day	44% 10% 17% 22% 7%	4091
	11th to 20th	Day	37% 9% 13% 28% 12% 1	4065
	21st to end	Day	33% 9% 16% 27% 12% 1	4180
September	1st to 10th	Day	39% 7% 13% 18% 19% 4	2280
	11th to 20th	Day	40% 5% 8% 24% 19% 4	2148
	21st to end	Day	47% 7% 9% 18% 17% 3	2054
October	1st to 10th	Day	39% 6% 9% 24% 18% 5%	1900
	11th to 20th	Day	36% 4 9% 25% 21% 5%	1900
	21st to end	Day	36% 4 9% 24% 21% 7%	2010
November	1st to 10th	Day	32% 4 9% 24% 26% 5%	1857
	11th to 20th	Day	35% 5% 9% 20% 22% 9%	1682
	21st to end	Day	36% 4 10% 24% 23% 3	1520
December	1st to 10th	Day	44% 6% 11% 21% 15% 3	1520
	11th to 20th	Day	33% 4 9% 27% 20% 7%	1906
	21st to end	Day	45% 6% 13% 22% 12% 2	2882
January	1st to 10th	Night	37% 5% 11% 21% 22% 4	4109
	11th to 20th	Night	41% 4 8% 22% 19% 6%	4120
	21st to end	Night	44% 4 7% 24% 17% 4	4532
February	1st to 10th	Night	38% 6% 12% 25% 17% 2	2470
	11th to 20th	Night	44% 5% 8% 20% 17% 6%	2405
	21st to end	Night	40% 6% 12% 21% 14% 6%	1817
March	1st to 10th	Night	49% 7% 8% 20% 13% 4	3418
	11th to 20th	Night	31% 5% 10% 24% 25% 5%	3480
	21st to end	Night	37% 6% 12% 22% 18% 4	3817
April	1st to 10th	Night	39% 7% 10% 20% 19% 5%	1965
	11th to 20th	Night	33% 6% 16% 21% 20% 5%	1875
	21st to end	Night	38% 6% 12% 25% 15% 3	1826
May	1st to 10th	Night	47% 9% 13% 19% 10% 2	2840
	11th to 20th	Night	48% 9% 11% 23% 9% 1	2813
	21st to end	Night	33% 10% 19% 26% 9% 3	2942
June	1st to 10th	Night	33% 9% 16% 27% 14%	1520
	11th to 20th	Night	34% 10% 18% 23% 13% 2	1520
	21st to end	Night	30% 10% 18% 22% 17% 2	1520
July	1st to 10th	Night	31% 11% 22% 20% 14% 3	2784
	11th to 20th	Night	38% 9% 19% 23% 9% 1	2786
	21st to end	Night	45% 9% 17% 20% 9%	2988
August	1st to 10th	Night	42% 9% 18% 25% 6% 1	2814
	11th to 20th	Night	39% 8% 14% 25% 13%	2812
	21st to end	Night	33% 7% 17% 32% 10% 2	3460
September	1st to 10th	Night	35% 7% 14% 20% 18% 4	1900
	11th to 20th	Night	39% 5% 9% 26% 18% 3	2028
	21st to end	Night	46% 6% 9% 20% 17% 2	2125
October	1st to 10th	Night	40% 5% 9% 24% 18% 4	2280
	11th to 20th	Night	34% 4 10% 25% 22% 4	2280
	21st to end	Night	34% 5% 10% 22% 26% 5%	2413
November	1st to 10th	Night	35% 4 8% 22% 24% 7%	2221
	11th to 20th	Night	34% 4 9% 23% 25% 6%	2493
	21st to end	Night	35% 5% 10% 24% 21% 5%	2660
December	1st to 10th	Night	43% 5% 10% 24% 14% 4	2660
	11th to 20th	Night	38% 4 10% 21% 20% 6%	3288
	21st to end	Night	40% 7% 13% 21% 17% 2	4756

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	21% 29% 29% 17% 5% 1	270
	11th to 20th	Day	25% 29% 29% 16% 2	270
	21st to end	Day	24% 25% 32% 16% 2	297
February	1st to 10th	Day	21% 25% 33% 16% 4	270
	11th to 20th	Day	30% 26% 34% 8% 1	270
	21st to end	Day	26% 19% 35% 17% 4	333
March	1st to 10th	Day	17% 23% 32% 22% 6%	460
	11th to 20th	Day	19% 22% 32% 19% 6% 2	460
	21st to end	Day	20% 17% 33% 23% 7% 1	506
April	1st to 10th	Day	20% 22% 27% 20% 10% 1	460
	11th to 20th	Day	17% 15% 28% 24% 13% 4	452
	21st to end	Day	23% 14% 28% 22% 10% 3	460
May	1st to 10th	Day	19% 15% 28% 22% 11% 4	463
	11th to 20th	Day	23% 9% 25% 23% 15% 5%	487
	21st to end	Day	16% 6% 21% 26% 21% 10%	529
June	1st to 10th	Day	13% 4 25% 28% 22% 8%	490
	11th to 20th	Day	12% 7% 20% 30% 19% 12%	490
	21st to end	Day	8% 5% 26% 34% 21% 6%	490
July	1st to 10th	Day	11% 3 17% 25% 30% 13%	485
	11th to 20th	Day	4 2 16% 32% 31% 14%	484
	21st to end	Day	12% 3 15% 33% 24% 13%	532
August	1st to 10th	Day	12% 5% 16% 28% 23% 16%	486
	11th to 20th	Day	13% 3 17% 27% 26% 14%	479
	21st to end	Day	10% 2 12% 30% 29% 18%	539
September	1st to 10th	Day	15% 5% 15% 27% 22% 17%	490
	11th to 20th	Day	15% 4 15% 26% 29% 12%	490
	21st to end	Day	27% 7% 18% 24% 18% 5%	490
October	1st to 10th	Day	19% 6% 20% 28% 22% 5%	490
	11th to 20th	Day	14% 12% 26% 28% 17% 3	490
	21st to end	Day	16% 12% 30% 28% 11% 3	507
November	1st to 10th	Day	17% 9% 28% 30% 14% 3	455
	11th to 20th	Day	19% 16% 30% 23% 11% 1	290
	21st to end	Day	18% 17% 33% 22% 9% 1	180
December	1st to 10th	Day	19% 19% 33% 23% 5% 1	180
	11th to 20th	Day	21% 19% 29% 22% 8% 1	180
	21st to end	Day	19% 20% 34% 16% 10% 1	231
January	1st to 10th	Night	17% 17% 36% 26% 4	760
	11th to 20th	Night	19% 15% 33% 29% 4	760
	21st to end	Night	17% 13% 41% 27% 3	836
February	1st to 10th	Night	15% 14% 38% 30% 4	760
	11th to 20th	Night	24% 15% 38% 22% 1	743
	21st to end	Night	21% 14% 37% 25% 3	628
March	1st to 10th	Night	16% 12% 37% 30% 4	760
	11th to 20th	Night	20% 15% 33% 24% 7% 1	760
	21st to end	Night	20% 10% 33% 30% 6% 1	836
April	1st to 10th	Night	18% 15% 33% 28% 6%	760
	11th to 20th	Night	14% 11% 33% 30% 12% 1	751
	21st to end	Night	19% 6% 29% 36% 9% 1	686
May	1st to 10th	Night	17% 6% 24% 36% 16% 1	570
	11th to 20th	Night	20% 4 23% 34% 17% 2	561
	21st to end	Night	15% 2 15% 38% 28% 2	537
June	1st to 10th	Night	10% 1 16% 48% 23% 2	380
	11th to 20th	Night	10% 3 14% 46% 26% 2	380
	21st to end	Night	9% 1 18% 45% 26% 2	380
July	1st to 10th	Night	12% 2 8% 37% 36% 5%	544
	11th to 20th	Night	6% 1 7% 39% 39% 7%	552
	21st to end	Night	8% 2 10% 41% 34% 5%	624
August	1st to 10th	Night	13% 1 8% 43% 31% 4	567
	11th to 20th	Night	12% 2 11% 38% 32% 5%	564
	21st to end	Night	12% 2 13% 34% 35% 5%	820
September	1st to 10th	Night	13% 1 11% 37% 30% 8%	760
	11th to 20th	Night	17% 2 11% 34% 31% 6%	760
	21st to end	Night	26% 3 17% 32% 21% 2	760
October	1st to 10th	Night	18% 5% 18% 32% 23% 4	760
	11th to 20th	Night	15% 8% 28% 32% 16% 1	760
	21st to end	Night	16% 9% 23% 36% 13% 2	805
November	1st to 10th	Night	15% 6% 26% 37% 13% 2	740
	11th to 20th	Night	16% 11% 28% 35% 10% 1	760
	21st to end	Night	17% 11% 29% 34% 8% 1	760
December	1st to 10th	Night	18% 11% 33% 31% 6%	760
	11th to 20th	Night	14% 9% 35% 36% 6%	760
	21st to end	Night	18% 12% 32% 35% 4	836

Page generated at 2024-10-21 02:20:06. Version ac07

Copyright © 2024 Attilla Danko.