Towns County Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Towns County Park clear sky chart from 2005-11-06 to 2025-05-26.

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	13% 8% 3 7% 5% 5% 5% 4 6% 7% 38%	114345
	Night	13% 8% 3 6% 4 4 4 4 6% 7% 40%	114925
Transparency	Day	41% 7% 11% 19% 17% 5%	118152
	Night	40% 7% 11% 19% 18% 5%	119257
Seeing	Day	20% 12% 22% 21% 16% 9%	15603
	Night	18% 11% 18% 29% 20% 4	25696

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% 11% 5% 5% 3 3 3 3 5% 6% 41%	4056
	11th to 20th	Day	13% 8% 5% 9% 4 3 3 2 4 4 47%	4060
	21st to end	Day	17% 12% 3 6% 4 3 3 3 4 5% 39%	4481
February	1st to 10th	Day	17% 11% 3 6% 4 4 4 4 4 5% 37%	2000
	11th to 20th	Day	21% 9% 3 7% 6% 3 3 3 5% 5% 35%	1948
	21st to end	Day	22% 9% 2 7% 4 4 3 3 4 5% 38%	1650
March	1st to 10th	Day	19% 8% 3 6% 5% 4 4 3 5% 6% 36%	4664
	11th to 20th	Day	11% 7% 2 6% 4 3 3 3 4 6% 51%	4980
	21st to end	Day	14% 8% 3 7% 5% 4 4 3 4 5% 43%	5465
April	1st to 10th	Day	13% 7% 1 7% 5% 4 5% 5% 7% 7% 40%	2225
	11th to 20th	Day	13% 6% 3 7% 5% 4 4 4 5% 7% 42%	2389
	21st to end	Day	13% 6% 3 6% 6% 4 5% 4 5% 7% 42%	2600
May	1st to 10th	Day	16% 9% 3 7% 5% 5% 5% 4 6% 7% 34%	4212
	11th to 20th	Day	16% 11% 3 9% 6% 5% 5% 4 6% 7% 28%	4211
	21st to end	Day	9% 7% 3 7% 5% 5% 6% 5% 7% 10% 37%	4541
June	1st to 10th	Day	10% 7% 4 8% 7% 6% 7% 5% 7% 9% 30%	2470
	11th to 20th	Day	7% 6% 2 7% 7% 6% 6% 6% 9% 9% 35%	2470
	21st to end	Day	8% 6% 2 8% 7% 5% 6% 6% 8% 10% 33%	2470
July	1st to 10th	Day	7% 6% 2 8% 7% 7% 7% 6% 9% 11% 30%	4120
	11th to 20th	Day	10% 6% 2 7% 6% 6% 7% 5% 8% 9% 32%	4120
	21st to end	Day	15% 10% 4 11% 8% 8% 8% 6% 8% 7% 16%	4466
August	1st to 10th	Day	8% 7% 3 7% 6% 6% 7% 5% 9% 11% 32%	4104
	11th to 20th	Day	9% 5% 2 6% 5% 5% 6% 5% 9% 13% 35%	3932
	21st to end	Day	8% 5% 2 7% 5% 5% 6% 4 7% 7% 45%	4158
September	1st to 10th	Day	11% 8% 3 7% 5% 7% 5% 5% 7% 8% 34%	2090
	11th to 20th	Day	13% 7% 2 8% 6% 6% 5% 4 7% 8% 34%	2090
	21st to end	Day	12% 6% 2 6% 5% 4 5% 4 7% 7% 42%	2090
October	1st to 10th	Day	11% 5% 2 5% 4 4 4 3 5% 6% 51%	2090
	11th to 20th	Day	12% 7% 1 4 3 3 4 3 3 5% 53%	1943
	21st to end	Day	13% 5% 2 5% 3 3 3 2 4 6% 53%	2090
November	1st to 10th	Day	12% 5% 1 5% 2 3 4 3 5% 6% 55%	1791
	11th to 20th	Day	13% 6% 3 4 3 4 4 3 6% 7% 49%	1800
	21st to end	Day	14% 8% 2 6% 4 3 4 3 4 6% 45%	1800
December	1st to 10th	Day	18% 7% 2 4 3 3 4 3 5% 5% 45%	2930
	11th to 20th	Day	19% 9% 3 6% 4 5% 5% 4 5% 6% 35%	3373
	21st to end	Day	13% 8% 5% 8% 4 4 4 3 5% 8% 38%	4466
January	1st to 10th	Night	13% 12% 3 6% 4 4 3 3 3 6% 41%	5889
	11th to 20th	Night	17% 9% 3 6% 4 3 3 2 5% 6% 42%	5900
	21st to end	Night	15% 12% 3 6% 3 3 3 2 6% 6% 39%	6472
February	1st to 10th	Night	15% 9% 3 6% 4 4 4 3 5% 7% 40%	2400
	11th to 20th	Night	20% 10% 4 6% 4 4 4 3 4 5% 36%	2338
	21st to end	Night	21% 10% 4 6% 3 4 4 3 4 6% 35%	1980
March	1st to 10th	Night	18% 13% 3 7% 5% 5% 4 4 4 5% 32%	5174
	11th to 20th	Night	11% 6% 1 4 3 3 4 4 5% 8% 49%	4980
	21st to end	Night	11% 9% 3 7% 5% 4 4 4 5% 6% 42%	5467
April	1st to 10th	Night	13% 7% 3 5% 4 4 4 3 6% 7% 45%	2190
	11th to 20th	Night	12% 6% 3 6% 3 3 4 3 5% 7% 47%	1960
	21st to end	Night	11% 6% 3 6% 4 5% 5% 4 5% 6% 46%	1800
May	1st to 10th	Night	13% 9% 3 7% 6% 5% 4 4 6% 8% 35%	2903
	11th to 20th	Night	16% 10% 3 9% 5% 4 5% 3 6% 7% 32%	2902
	21st to end	Night	7% 5% 2 7% 5% 5% 6% 5% 7% 11% 40%	3130
June	1st to 10th	Night	8% 8% 2 8% 6% 5% 5% 5% 8% 9% 35%	1710
	11th to 20th	Night	5% 6% 1 5% 5% 4 6% 4 8% 11% 45%	1710
	21st to end	Night	7% 6% 2 5% 5% 4 6% 5% 7% 10% 42%	1710
July	1st to 10th	Night	8% 6% 3 7% 6% 7% 6% 5% 7% 11% 32%	2840
	11th to 20th	Night	8% 6% 2 6% 5% 5% 6% 5% 9% 11% 36%	2840
	21st to end	Night	14% 10% 4 10% 7% 6% 6% 5% 7% 8% 23%	3087
August	1st to 10th	Night	7% 6% 2 7% 6% 5% 5% 5% 9% 13% 35%	2825
	11th to 20th	Night	12% 6% 2 7% 4 5% 4 4 6% 8% 41%	2879
	21st to end	Night	6% 5% 2 5% 4 4 4 4 7% 9% 48%	3476
September	1st to 10th	Night	9% 7% 2 7% 5% 5% 5% 4 7% 9% 39%	2080
	11th to 20th	Night	11% 7% 3 7% 5% 5% 5% 5% 7% 9% 39%	2090
	21st to end	Night	9% 6% 2 7% 4 4 5% 4 6% 8% 46%	2090
October	1st to 10th	Night	11% 5% 3 5% 3 3 3 3 4 6% 55%	2090
	11th to 20th	Night	12% 6% 2 5% 4 3 4 3 5% 6% 50%	2237
	21st to end	Night	10% 7% 2 5% 3 4 4 2 4 5% 54%	2508
November	1st to 10th	Night	11% 5% 2 5% 4 3 4 3 6% 7% 51%	2506
	11th to 20th	Night	14% 8% 2 5% 4 3 3 3 4 6% 48%	2600
	21st to end	Night	15% 9% 2 5% 4 3 3 4 5% 6% 43%	2600
December	1st to 10th	Night	17% 8% 3 6% 4 3 3 3 6% 6% 41%	4250
	11th to 20th	Night	19% 11% 4 7% 4 3 4 3 4 6% 35%	4822
	21st to end	Night	13% 11% 5% 9% 5% 4 4 3 6% 7% 33%	6490

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	41% 5% 5% 17% 26% 5%	4057
	11th to 20th	Day	37% 7% 6% 13% 28% 9%	4060
	21st to end	Day	46% 5% 5% 16% 19% 9%	4481
February	1st to 10th	Day	47% 5% 7% 18% 18% 5%	2000
	11th to 20th	Day	50% 5% 6% 16% 18% 6%	1958
	21st to end	Day	48% 5% 7% 13% 20% 7%	1650
March	1st to 10th	Day	47% 4 7% 13% 20% 8%	4664
	11th to 20th	Day	34% 5% 5% 16% 21% 19%	4980
	21st to end	Day	44% 4 7% 26% 15% 5%	5465
April	1st to 10th	Day	40% 6% 12% 21% 17% 4	2225
	11th to 20th	Day	40% 6% 10% 17% 23% 5%	2389
	21st to end	Day	40% 6% 11% 26% 15% 3	2600
May	1st to 10th	Day	46% 8% 13% 19% 13% 2	4250
	11th to 20th	Day	51% 9% 11% 20% 8% 1	4215
	21st to end	Day	39% 10% 14% 22% 15% 1	4554
June	1st to 10th	Day	47% 10% 16% 20% 6% 1	2470
	11th to 20th	Day	40% 10% 18% 20% 11% 1	2470
	21st to end	Day	41% 11% 17% 17% 11% 2	2470
July	1st to 10th	Day	43% 13% 21% 19% 5% 1	4055
	11th to 20th	Day	45% 11% 21% 17% 5% 1	4051
	21st to end	Day	64% 10% 13% 9% 4	4324
August	1st to 10th	Day	41% 10% 18% 24% 6%	4091
	11th to 20th	Day	36% 10% 22% 18% 12% 2	3971
	21st to end	Day	35% 9% 12% 28% 14% 1	4158
September	1st to 10th	Day	44% 9% 12% 17% 15% 3	2090
	11th to 20th	Day	46% 8% 11% 18% 16% 2	2090
	21st to end	Day	41% 7% 13% 16% 18% 6%	2090
October	1st to 10th	Day	26% 4 7% 16% 36% 10%	3480
	11th to 20th	Day	22% 3 6% 18% 26% 25%	3209
	21st to end	Day	26% 4 7% 25% 24% 14%	3428
November	1st to 10th	Day	32% 4 8% 16% 29% 11%	1791
	11th to 20th	Day	35% 4 6% 20% 26% 10%	1800
	21st to end	Day	40% 5% 7% 17% 26% 6%	1800
December	1st to 10th	Day	41% 4 6% 17% 26% 7%	2930
	11th to 20th	Day	49% 5% 7% 17% 18% 5%	3370
	21st to end	Day	41% 7% 11% 25% 14% 2	4466
January	1st to 10th	Night	42% 5% 7% 15% 26% 5%	5889
	11th to 20th	Night	41% 4 6% 16% 23% 9%	5900
	21st to end	Night	43% 5% 6% 16% 21% 8%	6472
February	1st to 10th	Night	44% 4 9% 19% 19% 5%	2400
	11th to 20th	Night	51% 4 6% 17% 18% 5%	2339
	21st to end	Night	50% 5% 8% 15% 18% 5%	1980
March	1st to 10th	Night	49% 8% 6% 13% 19% 5%	5174
	11th to 20th	Night	32% 5% 9% 18% 20% 16%	4980
	21st to end	Night	43% 4 9% 24% 14% 5%	5467
April	1st to 10th	Night	37% 6% 12% 20% 20% 4	2190
	11th to 20th	Night	37% 4 9% 22% 21% 6%	1960
	21st to end	Night	37% 7% 13% 26% 16% 2	1800
May	1st to 10th	Night	43% 11% 15% 20% 11% 1	2930
	11th to 20th	Night	46% 10% 15% 19% 10%	2903
	21st to end	Night	31% 12% 19% 25% 12% 1	3138
June	1st to 10th	Night	41% 11% 19% 20% 8% 1	1710
	11th to 20th	Night	30% 10% 24% 25% 9% 1	1710
	21st to end	Night	33% 12% 19% 21% 12% 3	1710
July	1st to 10th	Night	44% 11% 21% 19% 4	2795
	11th to 20th	Night	38% 13% 26% 18% 4 1	2786
	21st to end	Night	56% 12% 15% 11% 4 1	2988
August	1st to 10th	Night	36% 12% 26% 22% 4	2814
	11th to 20th	Night	38% 9% 25% 16% 12% 1	2906
	21st to end	Night	30% 8% 20% 28% 13% 1	3476
September	1st to 10th	Night	38% 11% 16% 18% 15% 3	2080
	11th to 20th	Night	41% 10% 13% 20% 16% 1	2090
	21st to end	Night	35% 8% 13% 20% 18% 6%	2090
October	1st to 10th	Night	26% 6% 9% 18% 34% 7%	3480
	11th to 20th	Night	23% 4 7% 18% 28% 20%	3710
	21st to end	Night	24% 6% 4 27% 26% 13%	4120
November	1st to 10th	Night	32% 5% 8% 21% 24% 10%	2506
	11th to 20th	Night	37% 5% 6% 18% 25% 10%	2600
	21st to end	Night	40% 5% 7% 21% 22% 6%	2600
December	1st to 10th	Night	43% 4 6% 17% 24% 6%	4250
	11th to 20th	Night	48% 7% 7% 14% 19% 5%	4824
	21st to end	Night	46% 7% 14% 19% 14% 2	6490

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	35% 23% 32% 9% 2	300
	11th to 20th	Day	38% 20% 25% 11% 5%	300
	21st to end	Day	30% 26% 32% 8% 4	330
February	1st to 10th	Day	28% 21% 37% 12% 2	300
	11th to 20th	Day	43% 24% 26% 6% 1	300
	21st to end	Day	36% 24% 30% 8% 2	249
March	1st to 10th	Day	31% 18% 28% 18% 4 1	380
	11th to 20th	Day	28% 17% 27% 22% 5% 1	500
	21st to end	Day	27% 21% 26% 20% 5% 1	550
April	1st to 10th	Day	26% 14% 28% 20% 10% 2	500
	11th to 20th	Day	17% 22% 26% 20% 13% 2	492
	21st to end	Day	20% 14% 23% 24% 15% 4	500
May	1st to 10th	Day	21% 16% 24% 21% 12% 5%	503
	11th to 20th	Day	17% 9% 23% 24% 15% 10%	527
	21st to end	Day	15% 8% 23% 22% 19% 13%	549
June	1st to 10th	Day	13% 5% 19% 26% 24% 12%	490
	11th to 20th	Day	9% 6% 19% 24% 26% 17%	490
	21st to end	Day	12% 4 21% 25% 21% 17%	490
July	1st to 10th	Day	9% 5% 10% 25% 29% 21%	485
	11th to 20th	Day	9% 4 11% 23% 29% 24%	484
	21st to end	Day	12% 3 11% 22% 27% 25%	532
August	1st to 10th	Day	15% 6% 13% 24% 20% 22%	486
	11th to 20th	Day	12% 6% 10% 24% 29% 19%	479
	21st to end	Day	14% 3 10% 23% 30% 20%	539
September	1st to 10th	Day	11% 3 15% 23% 34% 14%	490
	11th to 20th	Day	16% 4 16% 22% 29% 13%	490
	21st to end	Day	14% 6% 19% 26% 27% 8%	490
October	1st to 10th	Day	15% 6% 20% 30% 20% 8%	490
	11th to 20th	Day	18% 12% 22% 27% 18% 3	490
	21st to end	Day	18% 10% 26% 26% 18% 2	539
November	1st to 10th	Day	17% 14% 33% 23% 10% 4	329
	11th to 20th	Day	21% 21% 31% 20% 6%	300
	21st to end	Day	17% 22% 36% 16% 8% 1	300
December	1st to 10th	Day	34% 20% 28% 13% 4 1	300
	11th to 20th	Day	29% 17% 33% 15% 5% 1	300
	21st to end	Day	28% 22% 31% 14% 4 1	330
January	1st to 10th	Night	28% 16% 26% 25% 5% 1	800
	11th to 20th	Night	25% 20% 22% 25% 7%	800
	21st to end	Night	23% 18% 29% 27% 3	880
February	1st to 10th	Night	22% 16% 24% 33% 6%	800
	11th to 20th	Night	30% 18% 27% 23% 2	783
	21st to end	Night	28% 20% 25% 24% 3	660
March	1st to 10th	Night	22% 16% 28% 28% 6%	800
	11th to 20th	Night	22% 17% 23% 30% 8% 1	800
	21st to end	Night	20% 17% 25% 28% 10%	880
April	1st to 10th	Night	19% 15% 27% 28% 10% 1	790
	11th to 20th	Night	17% 12% 21% 33% 16% 1	593
	21st to end	Night	14% 10% 22% 35% 18% 2	600
May	1st to 10th	Night	16% 8% 19% 35% 21% 2	600
	11th to 20th	Night	16% 8% 14% 33% 25% 4	591
	21st to end	Night	12% 4 10% 34% 33% 8%	634
June	1st to 10th	Night	11% 4 9% 34% 34% 8%	570
	11th to 20th	Night	7% 4 8% 32% 35% 15%	570
	21st to end	Night	9% 2 7% 31% 42% 9%	570
July	1st to 10th	Night	9% 3 6% 23% 46% 11%	555
	11th to 20th	Night	10% 3 6% 21% 43% 17%	552
	21st to end	Night	11% 3 4 21% 45% 16%	624
August	1st to 10th	Night	10% 4 5% 23% 45% 14%	567
	11th to 20th	Night	11% 3 6% 29% 42% 9%	564
	21st to end	Night	13% 2 7% 23% 43% 13%	627
September	1st to 10th	Night	11% 3 10% 27% 39% 10%	750
	11th to 20th	Night	15% 3 12% 29% 34% 6%	760
	21st to end	Night	13% 5% 12% 34% 33% 4	760
October	1st to 10th	Night	14% 6% 17% 29% 27% 7%	760
	11th to 20th	Night	16% 9% 19% 33% 21% 3	760
	21st to end	Night	15% 13% 16% 35% 18% 3	836
November	1st to 10th	Night	13% 10% 20% 34% 20% 3	780
	11th to 20th	Night	19% 15% 19% 32% 13% 2	800
	21st to end	Night	21% 16% 17% 32% 13% 1	800
December	1st to 10th	Night	26% 15% 22% 28% 8% 1	800
	11th to 20th	Night	23% 15% 22% 32% 8% 1	800
	21st to end	Night	26% 15% 22% 31% 5%	880

Page generated at 2025-05-23 09:21:04. Version ac07

Copyright © 2025 Attilla Danko.